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Petitioner’s Environmental Report for Dicamba-Tolerant Soybean MON 87708 and 

Dicamba- and Glufosinate-Tolerant Cotton MON 88701

The undersigned submits this petition under 7 CFR §340.6 to request that the Administrator make a 

determination that the article should not be regulated under 7 CFR Part 340

November 22, 2013

OECD Unique Identifiers: MON-877Ø8-9 (soybean) and MON-887Ø1-3 (cotton)

Monsanto Petition Numbers: 10-SY-210U (soybean) and 12-CT-244U/12-CT-244U-S (cotton)

USDA Petition Numbers: 10-188-01p (soybean) and 12-185-01p_a1 (cotton)

Submitted by:

Rhonda M. Mannion, B.S.

Marianne Malven, M.S.

Monsanto Company

800 North Lindbergh Blvd.

St. Louis, MO 63167

Phone: (314) 694-8785

Fax: (314) 694-3080

E-mail: rhonda.m.mannion@monsanto.com

E-mail: marianne.malven@monsanto.com

Prepared by:

L.A. Burzio, Ph.D., B.A. Comstock, B.S., A. Deffenbaugh, B.S., K.S. Giddings, Ph.D., R.L. Girault M.S., 

G.G. Harrigan, Ph.D., J.L. Honegger, Ph.D., D.L. Kendrick, M.S., R.M. Mannion B.S., M.C. McCann, M.S., 

B. Morrison, M.S., K.E. Niemeyer B.S., G.J. Rogan, M.S., R.W. Schneider, B.S., J.K. Soteres Ph.D., 

C. Wang, Ph.D., G. Watson, Ph.D., J. Wright, Ph.D.

Contributors and/or Principal Investigators:

C. Arnevik, M.S., J. Berry, M.S., M. Bleeke, Ph.D., S.L. Bollman, Ph.D., C.R. Brown, M.S., K. Carr, M.S., 

D. Carson, Ph.D., C.M. Dalton, B.A., R.C. Dobert, Ph.D, A.J. Evans, M.P.H., M.J. Granto, B.A., 

R.A. Heeren, B.S., S. Hill, M.S., A.C. Hood, B.S., K.M. Huizinga, Ph.D., J. Kronenberg, Ph.D., T.C. Laufer, 

M.S., K.D. Lawry, M.S., V. Leopold, M.S., F. Lloyd, M.S., S.L. Phillips, M.S., J.F. Rice, Ph.D., Z. Song, M.S., 

R.S. Thoma, M.S., Q. Tian, Ph.D. M. Miller, Ph.D., M. Starke, Ph.D., J. Whitsel, M.S., M.A. Wideman
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 2 of 946

Release of Information

Monsanto is submitting the information in this petition for review by the USDA as part of the 

regulatory process. By submitting this information, Monsanto does not authorize its release to any 

third party. In the event the USDA receives a Freedom of Information Act request, pursuant to 5 

U.S.C. § 552, and 7 CFR Part 1, covering all or some of this information, Monsanto expects that, in 

advance of the release of the document(s), USDA will provide Monsanto with a copy of the material 

proposed to be released and the opportunity to object to the release of any information based on 

appropriate legal grounds, e.g., responsiveness, confidentiality, and/or competitive concerns. 

Monsanto understands that a copy of this information may be made available to the public in a 

reading room and upon individual request as part of a public comment period. Except in 

accordance with the foregoing, Monsanto does not authorize the release, publication or other 

distribution of this information (including website posting) without Monsanto's prior notice and 

consent.

©2013 Monsanto Company. All Rights Reserved.

This document is protected under copyright law. This document is for use only by the regulatory 

authority to which it has been submitted by Monsanto Company and only in support of actions 

requested by Monsanto Company. Any other use of this material, without prior written consent of 

Monsanto, is strictly prohibited. By submitting this document, Monsanto does not grant any party 

or entity any right to use or license the information or intellectual property described in this 

document.
Certification 

The undersigned certifies that, to the best knowledge and belief of the undersigned, this report 

includes all information and views on which to base a determination, and that it includes all relevant 

data and information known to the petitioner that are unfavorable to the petition. 

Rhonda Mannion, B.S. 

Regulatory Affairs Manager 

Tel: (314) 694-8785 

Fax: (314) 694-8414 

Marianne Malven, M.S. 

Regulatory Affairs Manager 

Tel: (314) 694-2225 

Fax: (314) 694-8414 

Address: 

Monsanto Company 

800 North Lindbergh Blvd. 

St. Louis, MO 63167 

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TABLE OF CONTENTS

I. Purpose and Need........................................................................................................................................13

I.A. Purpose of MON 87708 Soybean (DT Soybean) and MON 88701 Cotton 

(DGT Cotton).......................................................................................................................14

I.B. Regulatory Authority..................................................................................................................14

I.B.1. USDA-APHIS Authority..........................................................................................14

I.B.2. FDA Authority ...........................................................................................................17

I.B.3. EPA Authority............................................................................................................17

I.B.4. Center for Food Safety v. Vilsack and APHIS’s Regulatory Authority ....................19

I.B.5. Threatened and Endangered Species......................................................................22

I.C. Purpose and Need for Aphis Action .......................................................................................24

I.D. Scoping for the Environmental Report..................................................................................24

II. Affected Environment...............................................................................................................................25

II.A. Introduction...............................................................................................................................25

II.B. Agricultural Production of Soybeans & Cotton ...................................................................26

II.B.1. Agricultural Production of Soybeans.....................................................................26

II.B.2. Agricultural Production of Cotton ........................................................................50

II.C. Physical Environment ..............................................................................................................77

II.C.1. Land Use and Soil Quality ......................................................................................77

II.C.2. Water Resources.......................................................................................................80

II.C.3. Air Quality.................................................................................................................83

II.C.4. Climate Change.........................................................................................................85

II.D. Biological Resources ................................................................................................................86

II.D.1. Biological Resources - Soybean .............................................................................86

II.D.2. Biological Resources – Cotton...............................................................................93

II.E. Human Health...........................................................................................................................99
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II.E.1. Consumer Health ...................................................................................................100

II.E.2. Worker Health........................................................................................................103

II.F. Animal Health..........................................................................................................................104

II.F.1. Animal Feed: Soybean ...........................................................................................104

II.F.2. Animal Feed: Cotton..............................................................................................105

II.F.3. FDA Consultation Process ...................................................................................106

II.F.4. EPA Dicamba Tolerance Assessment.................................................................106

II.G. Socioeconomics......................................................................................................................107

II.G.1. Domestic Economic Environments of Soybean and Cotton.........................107

II.G.2. Trade Economic Environments of Soybean and Cotton................................128

II.G.3. Public Perceptions of Genetically Engineered Crops in Food .......................132

III. Alternatives..............................................................................................................................................134

III.A. Introduction & Description of Alternatives......................................................................134

III.B. Alternative 1 – Deny Both Petitions for Determination of Nonregulated Status 

(No Action Alternative).....................................................................................................135

III.C. Alternative 2 - Approve the Petition for Determination of Nonregulated Status 

of DT Soybean, and Deny the Petition for Determination of Nonregulated 

Status of DGT Cotton.......................................................................................................136

III.D. Alternative 3 - Approve the Petition for Determination of Nonregulated 

Status of DGT Cotton, and Deny the Petition for Determination of 

Nonregulated Status of DT Soybean...............................................................................137

III.E. Alternative 4 – Grant Both Petitions for Determination of Nonregulated 

Status (Full Deregulation of DT Soybean and DGT Cotton) .....................................138

III.F. Alternatives Considered But Eliminated from Detailed Evaluation..............................139

III.F.1. Approve Both Petitions For Determination of Nonregulated Status 

Only in Part (Isolation Distances, Geographic Restrictions, and 

Other Restrictions On Use).................................................................................139

III.F.2. Require Testing for DT Soybean and DGT Cotton........................................140

III.F.3. Ban All Planting of DT Soybean and DGT Cotton ........................................140

III.G. Comparison of Impacts By Alternative Matrix ................................................................141
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IV. Environmental Consequences...............................................................................................................154

IV.A. Methodologies and Assumptions Used in the Analysis...................................................156

IV.A.1. Methodology and Assumptions Used for DT Soybean..................................156

IV.A.2. Methodology and Assumptions Used for DGT Cotton ................................163

IV.B. Agricultural Production of Soybeans & Cotton................................................................169

IV.B.1. Crop Use and Biology ..........................................................................................169

IV.B.2. General Agronomic Practices.............................................................................173

IV.B.3. Tillage......................................................................................................................174

IV.B.4. Pest Management..................................................................................................176

IV.B.5. Weed Management ...............................................................................................177

IV.B.6. Weed Resistance....................................................................................................186

IV.B.7. Organic Production ..............................................................................................191

IV.B.8. Other Specialty Market Production....................................................................195

IV.B.9. Seed Production ....................................................................................................197

IV.C. Physical Environment...........................................................................................................199

IV.C.1. Land Use Impacts.................................................................................................200

IV.C.2. Soil Quality Impacts.............................................................................................203

IV.C.3. Water Quality Impacts.........................................................................................208

IV.C.4. Air Quality Impacts..............................................................................................217

IV.C.5. Climate Change Impacts......................................................................................221

IV.D. Biological Impacts From DT Soybean & DGT Cotton .................................................223

IV.D.1. Animal Communities...........................................................................................223

IV.D.2. Plant Communities...............................................................................................226

IV.D.3. Gene Flow and Weediness .................................................................................232

IV.D.4. Microorganisms....................................................................................................234

IV.D.5. Bioiversity..............................................................................................................236
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IV.E. Human Health and Safety Impacts.....................................................................................237

IV.E.1. Human Health.......................................................................................................237

IV.E.2. Worker Health.......................................................................................................245

IV.F. Animal Feed and Animal Health .........................................................................................248

IV.F.1. No Action Alternative for Both DGT Cotton and DT Soybean ..................249

IV.F.2. Approval in Whole of DT Soybean, but not DGT Cotton............................249

IV.F.3. Approval In Whole of DGT Cotton, but not DT Soybean ...........................250

IV.F.4. Approval in Whole of DT Soybean and DGT Cotton ...................................251

IV.G. Socioeconomic Impacts.......................................................................................................252

IV.G.1. Domestic Economic Environment: Soybean and Cotton .............................252

IV.G.2. Trade Economic Environment..........................................................................256

IV.G.3. The Organic Segment..........................................................................................260

IV.H. Other Impacts and Mitigation Measures...........................................................................262

IV.H.1. Unavoidable Impacts...........................................................................................262

IV.H.2. Short-term vs. Long-term Productivity of the Environment........................264

IV.H.3. Irreversible Resource Commitments.................................................................265

IV.H.4. Mitigation Measures.............................................................................................265

V. Cumulative Impacts..................................................................................................................................271

V.A. Structure of the Cumulative Impacts Analysis ...................................................................272

V.B. Class of Actions to be Analyzed ...........................................................................................272

V.C. Geographical and Temporal Boundaries for the Analysis................................................272

V.D. Resources Analyzed................................................................................................................273

V.E. Magnitude of Effects on Resources.....................................................................................273

V.F. Assumptions Used for Cumulative Impacts Analysis........................................................273

V.G. Conventional Breeding with Other GE-derived or non-GE Crops...............................274

V.H. Demonstrated Genetic and Phenotypic Stability...............................................................276
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V.I. Combined Trait Product Performance in Principle and in Practice .................................277

V.J. Cumulative Impacts: Acreage and Area of Soybean and Cotton Production .................278

V.J.1. Cumulative Impacts: Agronomic Practices..........................................................279

V.J.2. Soybean .....................................................................................................................279

V.J.3. Cotton........................................................................................................................280

V.J.4. Cumulative Impacts of Herbicides........................................................................280

V.K. Net Impact of DT soybean and DGT Cotton on overall herbicide use........................282

V.L. Cumulative Impacts: Seed Production.................................................................................284

V.M. Cumulative Impacts: Organic Production..........................................................................284

V.N. Cumulative Impacts: Soil Quality.........................................................................................285

V.O. Cumulative Impacts: Water Resources................................................................................286

V.P. Cumulative Impacts: Air Quality...........................................................................................288

V.Q. Cumulative Impacts: Climate Change .................................................................................289

V.R. Cumulative Impacts: Animal Communities........................................................................289

V.S. Cumulative Impacts: Plants Communities...........................................................................290

V.T. Cumulative Impacts: Gene Flow and Weediness...............................................................292

V.T.1. Soybean....................................................................................................................292

V.T.2. Cotton ......................................................................................................................293

V.T.3. Conclusion...............................................................................................................293

V.U. Cumulative Impacts: Microorganisms.................................................................................294

V.V. Cumulative Impacts: Biodiversity.........................................................................................295

V.W. Cumulative Impacts: Human Health ..................................................................................296

V.X. Cumulative Impacts: Animal Feed .......................................................................................297

V.Y. Cumulative Impacts: Domestic Economic Environment.................................................298

V.Z. Cumulative Impacts: Trade Economic Environment .......................................................299

VI. Threatened and Endangered Species Analysis....................................................................................300
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VI.A. Potential for GE Plant to Affect Threatened or Endangered Species..........................301

VI.B. Potential for DT soybean to Affect Threatened or Endangered Species .....................301

VI.C. Potential for DGT cotton to Affect Threatened or Endangered Species.....................303

VI.D. Potential Impacts of Dicamba Use on Threatened and endangered species...............304

VII. Consideration of Executive Orders, Standards, And Treaties Relating To 

Environmental Impacts...................................................................................................................309

VII.A. Executive Orders (EO) with Domestic Implications.....................................................309

VII.B. International Implications...................................................................................................311

VII.C. Impacts On Unique Characteristics of Geographic Areas ............................................313

VII.D. National Historic Preservation Act (NHPA) of 1966 As Amended ...........................314

VIII. REFERENCES ...................................................................................................................................316

Appendix A: Dicamba Herbicide Usage, Herbicide Displacement, and Comparative 

Analysis of Alternative Registered Herbicides.............................................................................356

Appendix B: Herbicide Resistance ..............................................................................................................522

Appendix C: Effects of Changes in Farming Practices on Water, Soil and Air Due to Use of 

DT Soybeans and DGT Cotton.....................................................................................................626

Appendix D: Potential for Spray Drift and Volatilization to Affect Adjacent Crop 

& Non-Crop Areas, and Mitigation Measures.............................................................................685

Appendix E: Health and Safety Risks of Dicamba to the General Population & Workers..............708

Appendix F: Potential Impacts on Wildlife, Plants, Ecosystems, and Threatened or 

Endangered Species from Dicamba Usage ..................................................................................730

Appendix G: Character and Quality of DT Soybean and DGT Cotton Traits...................................861

Appendix H: Presence of Dicamba-Tolerant Soybean and Dicamba-and-GlufosinateTolerant Cotton in Human Food or Animal Feed......................................................................884
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TABLE OF TABLES

Table II.B-1 Soybean Production in the U.S., 1999 – 20121....................................................................30

Table II.B-2. U.S. Soybean Production by Region and State in 20121....................................................31

Table II.B-3. Common Weeds in Soybean Production: Midwest Region ............................................37

Table II.B-4. Common Weeds in Soybean Production: Southeast Region ..........................................37

Table II.B-5. Common Weeds in Soybean Production: Eastern Coastal Region................................38

Table II.B-6. Ten Most Widely Used Alternative Herbicides in U.S. Soybean Production in 

2012 ......................................................................................................................................................40

Table II.B-9. Known Weed Resistance in the Southern U.S.1.................................................................45

Table II.B-10. Known Weed Resistance in the Midwest U.S. 1...............................................................46

Table II.B-11. Deregulated Biotechnology-derived Soybean Products1.................................................47

Table II.B-12. Cotton Production in the U.S., 2000-20111......................................................................55

Table II.B-13. U.S. Cotton Production by Region and State in 20111....................................................56

Table II.B-14. Common weeds in Cotton Production in the Southeast Region of the U.S.1,2............61

Table II.B-15. Common weeds in Cotton Production in the Midsouth Region of the U.S.1,2.............62

Table II.B-16. Common weeds in Cotton Production in the Southwest Region of the U.S.1,2...........62

Table II.B-17. Common weeds in Cotton Production in the West Region of the U.S.1,2.....................62

Table II.B-18. Ten Most Widely Used Alternative Herbicides in U.S. Cotton Production ................66

Table II.B-19. Known Weed Resistance in the Southern U.S. in 20121.................................................72

Table II.B-20. Deregulated Biotechnology-derived Cotton Products1...................................................73

Table II.D-1. Summary of Published Literature on Soybean Cross Pollination ...................................91

Table II.D-2. Summary of Published Literature on Cotton Cross Pollination .....................................97

Table II.G-1. U.S. soybean supply and disappearance12009/10...........................................................109

Table II.G-2. Soybean crop value by state1................................................................................................111

Table II.G-3. Soybean commodity costs and returns, 2011. ...................................................................115

Table II.G-4. Percentage of soybean acreage planted with GE herbicide-tolerant soybean 

varieties by state and for the U.S....................................................................................................117
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Table II.G-5. Common U.S. Glyphosate-Resistant Weeds.....................................................................118

Table II.G-6. U.S. Cotton Production Costs and Returns From 2006 to 20111.................................122

Table II.G-7. Regional U.S. Cotton Production Costs and Returns in 20111.....................................123

Table II.G-8. Cotton Production in the U.S., 2000-20101.......................................................................126

Table II.G-9. U.S. Cotton Production by Region and State in 20101....................................................127

Table II.G-10. U.S. Export Markets for Soybean and Soybean Products.............................................129

Table II.G-11. World Soybean Exports in 2009/2010. ...........................................................................130

Table II.G-12. Top 10 U.S. Soybean Export Markets in 2010/2011.....................................................130

Table II.G-13. U.S. and Rest of World (ROW) Soybean Supply and Disappearance1

2009/10..............................................................................................................................................131

Table II.G-14. World Soybean Production in 2009/2010.......................................................................131

Table III.G-1 Summary of Impacts of Each Alternative.........................................................................141

Table IV.A-1. Summary of Dicamba Uses on Soybean..........................................................................157

Table IV.A-2. Proposed Weed Management System Recommendations for DT Soybean 

Combined with Glyphosate-Tolerant Soybean............................................................................159

Table IV.A-3. Projected Dicamba Use on DT Soybean.........................................................................161

Table IV.A-4. Anticipated Weed Management Recommendations for DGT Cotton 

Combined with Glyphosate-Tolerant Cotton Systems for MO, AR, TN, AL, FL, 

GA, NC, SC, VA, LA, MS, eastern TXand CA.1,2......................................................................166

Table IV.A-5. Anticipated Weed Management Recommendations for DGT Cotton 

Combined with Glyphosate-Tolerant Cotton Systems for western TX, NM, KS, OK, 

and AZ 1,2...........................................................................................................................................167

Table IV.G-1. Status of Import Approvals of DT Soybean in Key US Soybean Export 

Markets ..............................................................................................................................................258

Table IV.G-2. Status of Import Approvals of DGT Cotton in Key US Cotton Export 

Markets ..............................................................................................................................................259
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TABLE OF FIGURES

Figure II.B-1. Planted Soybean Acres by County in the U.S. in 2012. ...................................................29

Figure II.B-2. Planted Upland Cotton Acres by County in the U.S. in 2012..........................................53

Figure II.B-3. Planted Pima Cotton Acres by County in the U.S. in 2012..............................................54

Figure II.G-1. Distribution of U.S. Soybean Oil Consumption in 2010. .............................................110

Figure II.G-2. Planted Soybean Acreage by County in the U.S. in 20121.............................................112

Figure II.G-3. General flow of U.S. soybean commodities.....................................................................113
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I. PURPOSE AND NEED

Monsanto has developed a new biotechnology-derived soybean (Glycine max), designated as event 

MON 87708 (“DT soybean”), that is tolerant to dicamba herbicide, and a new biotechnologyderived cotton (Gossypium spp.), designated as event MON 88701 (“DGT cotton”), that is tolerant to 

dicamba and glufosinate herbicides. Monsanto submitted petitions for determinations of 

nonregulated status for DT soybean and DGT cotton three and one years ago, respectively. At the 

time of the initial submissions, Monsanto provided the U.S. Department of Agriculture (USDA) 

Animal and Plant Health Inspection Service (APHIS) with lengthy scientific materials and 

Environmental Reports. In the years that followed, APHIS has reviewed those materials in detail. 

The appropriate framework for APHIS’s review of such petitions is the Plant Protection Act (PPA) 

and associated regulations at 7 CFR Part 340. For more than two decades, through many dozens of 

Environmental Assessments, two Environmental Impact Statements (EIS), and in multiple litigation

matters, APHIS has explained that its regulatory role in the Coordinated Framework under the PPA 

is limited to assessing whether the subject organisms present a “plant pest risk.” See Section I.B.1.

From 2007-2013, litigation in the U.S. District Court for the Northern District of California and 

appellate proceedings in the U.S. Court of Appeals for the Ninth Circuit focused on the scope of 

APHIS’s authority under the PPA and APHIS’s related obligations, if any, under the National 

Environmental Policy Act (NEPA) and the Endangered Species Act (ESA). One of the principal 

questions in those suits was whether APHIS has a responsibility under NEPA or ESA to examine 

the effects of herbicide uses in connection with the genetically engineered (GE) crop at issue, or 

instead whether the U.S. Environmental Protection Agency (EPA) has such responsibility. 

Monsanto intervened in that litigation, and together Monsanto and APHIS succeeded in winning 

both at the district court level and before the appellate court. See Section I.B.4 for more discussion. 

The court decision left no doubt that APHIS’s traditional interpretation of its authority under the 

PPA was indeed correct, and that APHIS was not required by the PPA, NEPA or the ESA to 

address such herbicide uses in the manner plaintiffs in the litigation alleged. However, just days 

before the ultimate conclusion of that litigation APHIS issued a notice announcing that it would 

indeed prepare an EIS related, at least in part, to such herbicide uses.

Monsanto does not believe that the type of EIS described by APHIS’s May 16, 2013, Notice of 

Intent (NOI) to prepare an EIS addressing herbicide uses is necessary or appropriate, particularly in 

light of these recent litigation decisions. Indeed, such an EIS could duplicate many of the analyses 

to be performed by EPA under its authorities. Both DT soybean and DGT cotton are needed by 

American farmers as soon as possible, and Monsanto has found it difficult to justify a delay in 

review of these technologies simply to perform duplicative analyses. 

That said, Monsanto is consolidating information in this updated Environmental Report to ensure 

that there is no doubt the record is complete, and so that APHIS can refer to this material and can 

finish its intended EIS for DT soybean and DGT cotton as soon as possible. Accordingly, this 

updated Environmental Report for both technologies integrates and supplements the materials 

previously provided to APHIS on July 2010 (for DT soybean petition and Environmental Report), 

October 2012 (supplemental NEPA analysis for DT soybean), December 2012 (supplemental 

NEPA analysis for DT soybean), January 2013 (supplemental NEPA analysis for DT soybean), July 

2012 (for DGT cotton petition), and May 2013 (for DGT cotton Environmental Report). 
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I.A. PURPOSE OF MON 87708 SOYBEAN (DT SOYBEAN) AND MON 88701 

COTTON (DGT COTTON)

Monsanto has developed a new biotechnology-derived soybean (Glycine max), designated as event 

MON 87708 (“DT soybean”), that is tolerant to dicamba herbicide, and a new biotechnologyderived cotton (Gossypium spp.), designated as event MON 88701 (“DGT cotton”), that is tolerant to 

dicamba and glufosinate herbicides. DT soybean and DGT cotton are genetically engineered to be 

resistant to dicamba through the insertion of a gene (from Stenotrophomonas maltophilia) that expresses 

a mono-oxygenase enzyme that rapidly demethylates dicamba and renders it inactive, thereby 

conferring tolerance to dicamba. DGT cotton also contains a bialaphos resistance (bar) gene (from 

Streptomyces hygroscopicus) that expresses the phosphinothricin N-acetyltransferase (PAT) protein to 

confer tolerance to glufosinate herbicide. Both DT soybean and DGT cotton combined will be 

combined with glyphosate-tolerance traits utilizing traditional breeding techniques.

The in-crop use of dicamba for soybean and dicamba and glufosinate herbicides for cotton, in 

addition to glyphosate herbicide, provides enhanced weed management options in soybean and 

cotton cultivation to control a broad spectrum of grass and broadleaf weed species. These uses of 

dicamba and glufosinate also provide effective control of weeds resistant to several herbicide 

families, where such weeds may occur. Effective weed management practices in agricultural systems

helps ensure that herbicide-resistant weeds do not become a limiting factor in crop production. One 

of the most recommended weed management practices by weed scientists is the use of multiple 

herbicide modes-of-action when appropriate, especially to mitigate the evolution and development 

of herbicide resistant weeds. Successful integration of DT soybean and DGT cotton can enhance 

weed management systems by providing additional in-crop herbicide modes-of-action, while 

fostering growers’ use of established production practices, reduced tillage systems, and the same 

planting and harvesting machinery. DT soybean and DGT cotton will also help growers maintain 

yield and quality to meet the growing need for food, feed and fiber, both domestically and for export 

markets.

I.B. REGULATORY AUTHORITY

Since 1986, the U.S. Government has regulated genetically engineered (GE) organisms pursuant to a 

regulatory framework known as the Coordinated Framework for the Regulation of Biotechnology 

(Coordinated Framework) (U.S. FDA 1986; 1992). Under the Coordinated Framework, the 

responsibility for regulatory oversight falls on three federal agencies: the U.S. Food and Drug 

Administration (FDA), the Animal and Plant Health Inspection Service (APHIS) of the U.S. 

Department of Agriculture (USDA), and the U.S. Environmental Protection Agency (EPA). The 

FDA reviews the safety of food consumed by humans and animals under the Federal Food, Drug 

and Cosmetic Act (FFDCA) (21 U.S.C. §§ 301 et seq.); APHIS examines whether a plant itself 

presents a “plant pest” risk under the Plant Protection Act (PPA) (7 U.S.C. §§ 7701 et seq.); and EPA 

regulates potential environmental and human-health concerns regarding pesticide use by setting 

maximum permissible pesticide residues on crops under the FFDCA and prescribing the conditions 

under which associated herbicides and other pesticides can be used under the Federal Insecticide, 

Fungicide and Rodenticide Act (FIFRA) (7 U.S.C. §§ 136 et seq.).

I.B.1. USDA-APHIS Authority 

APHIS regulates GE crops under its “plant pest” PPA authority. Under the PPA, to constitute a 

plant pest under the PPA, defined by 7 U.S.C. §7702(14), an organism must (1) fall within certain 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 15 of 946

enumerated categories of living things and (2) injure or cause disease in plants. To meet the first 

requirement, an organism must be:

[the] living stage of any of the following ... (A) A protozoan. (B) A 

nonhuman animal. (C) A parasitic plant. (D) A bacterium. (E) A 

fungus. (F) A virus or viroid. (G) An infectious agent or other 

pathogen. (H) Any article similar to or allied with any of the articles 

specified in the preceding subparagraphs.

7 U.S.C. §7702(14). 

Facially, GE plants do not satisfy this first requirement. The only type of plant that can even be a 

plant pest is a parasitic one (i.e., a plant that depends on other plants for sustenance). The genetic 

elements used in many GE plants, however, are derived from (or inserted into target plants using) 

bacteria or viruses—organisms that may qualify as plant pests. It is therefore theoretically possible 

for a GE plant to present a plant-pest risk, and for that reason APHIS presumes under its governing 

GE/plant-pest regulations that these GE crops pose plant-pest risks. 

As to the second requirement, APHIS has never considered potential gene flow between 

commercial crops to constitute the sort of “injury” or “disease” for purposes of the definition of 

“plant pest.” That interpretation is based in part on the fact that cross-pollination is a natural 

reproductive process that has no effect on existing plants. Instead, any such “effect” would only be 

to the character of the offspring and is not in any ordinary sense considered injurious. APHIS has

also never considered the pesticides applied to a crop—which are separately regulated by EPA—to 

be relevant to the analysis of the plant-pest risk of a GE plant. APHIS’s interpretations of its plantpest authority have been upheld by federal courts. Center for Food Safety v. Vilsack, 718 F.3d 829 (9th 

Cir. 2013); Center for Food Safety v. Vilsack, 844 F. Supp. 2d 1006 (N.D. Cal. 2012). ); see also Brief for 

Federal Appellees at 17-18, Vilsack, 718 F.3d 829 (June 6, 2013) available at 2012 WL 2313232 (“The 

harms cited by plaintiffs [i.e., herbicide impacts and potential cross-pollination] have never been 

treated as APHIS’s statutory justification for regulation under its plant pest authority, and APHIS 

reasonably concluded that they do not qualify as plant pest risks pursuant to the Plant Protection 

Act.”); id. at 29-30 (“Herbicides are not plant pests. Moreover, risks from glyphosate do not qualify 

as plant pest risks because glyphosate application does not result from Roundup Ready Alfalfa itself, 

but rather from independent human action.” (citations omitted)); id. at 30 (APHIS “has not 

considered increased herbicide use to be a plant pest harm in its analyses of other genetically 

engineered herbicide resistant crops.”).

In contrast to gene flow, the types of injuries that typically fall within USDA plant-pest authority are 

substantial threats to plants from organisms such as insects and mites (like the Asian Longhorned 

Beetle and Mediterranean fruit fly) and viruses and bacteria (like the potato virus and Ralstonia), 

which can devastate entire crops and forests.1 

 

1 See APHIS, Plant Health, http://www.aphis.usda.gov/plant_health/plant_pest_info/ (listing plant pests); 7 U.S.C. §7702(14); 

APHIS, About APHIS, http://www.aphis.usda.gov/about_aphis/. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 16 of 946

APHIS’s GE crop/plant-pest regulations are found at 7 CFR Part 340. Those regulations were 

promulgated pursuant to APHIS authority under statutes that were ultimately recodified as the PPA. 

Specifically, Congress enacted the PPA in 2000 to replace and supersede the Plant Quarantine Act, 

the Federal Plant Pest Act, and the Federal Noxious Weed Act. See Pub. L. No. 106-224, 114 Stat. 

438 (codified at 42 U.S.C. § 7701 et seq.); see also Ctr. for Food Safety v. Vilsack, 844 F. Supp. 2d 1006, 

1013 (N.D. Cal. 2012). “The PPA’s definition of ‘plant pest’ is materially the same as the 1957 

Federal Plant Pest Act’s definition of plant pest,” however. Ctr. for Food Safety v. Vilsack, 718 F.3d 

829, 834 (9th Cir. 2013). In addition, Congress expressly provided that APHIS’s preexisting 

regulations “shall remain in effect until” APHIS replaces them. 7 U.S.C. §7758(c). APHIS has not 

amended its Part 340 regulations since enactment of the PPA and thus the PPA expressly provides 

that they shall continue to govern.

Under the PPA, APHIS has authority to regulate the introduction (importation, interstate 

movement, or release into the environment) of certain plants pests and products. Certain GE 

organisms are initially presumed to be regulated articles by regulation if the donor organism, 

recipient organism, vector, or vector agent used in engineering the organism belongs to one of the 

taxa listed in the regulation (7 CFR 340.2) and the donor, recipient, or vector organism is considered 

a plant pest, or its plant pest status is unknown. 

Any person may petition the agency for a determination that a regulated article is unlikely to pose a 

plant pest risk and, therefore, should be no longer regulated under the plant pest provisions of the 

PPA or the regulations at 7 CFR Part 340. The petitioner is required to provide information under § 

340.6(c)(4) related to plant pest risk that the agency may use to determine whether the regulated 

article is unlikely to present a greater plant pest risk than the unmodified organism. A GE organism 

is no longer subject to the regulatory requirements of 7 CFR Part 340 or the plant pest provisions of 

the PPA when APHIS reaches a final determination that it is unlikely to pose a plant pest risk and 

grants a petition for nonregulated status. In such a case, APHIS authorizations—including permits 

and modifications—are no longer required for the environmental release, importation, or interstate 

movement of the nonregulated article or its progeny. 

It was pursuant to these APHIS regulations that Monsanto submitted in 2010 a petition for a 

determination of nonregulated status for DT soybean,2and in 2012 a petition for a determination of 

nonregulated status for DGT cotton.3 Monsanto’s petitions also sought determinations of 

nonregulated status for any progeny derived from crosses between DT soybean and conventional 

soybean, DGT cotton and conventional cotton, and any progeny derived from crosses of DT 

 

2 Petition for the Determination of Nonregulated Status for Dicamba-Tolerant Soybean MON 87708, Monsanto Petition 

Number: 10-SY-201U (July 6, 2010) ; Supplemental Information to Support the NEPA Analysis for the Determination of 

Nonregulated Status of Dicamba-Tolerant Soybean MON 87708, Petition # 10-188-01p (Oct. 11, 2012); Supplemental 

Information to Support the NEPA Analysis for the Determination of Nonregulated Status of Dicamba-Tolerant Soybean MON 

87708, Petition # 10-188-01p (Dec. 14, 2012); Supplemental Information to Support the NEPA Analysis for the Determination 

of Nonregulated Status of Dicamba-Tolerant Soybean MON 87708, Petition # 10-188-01p (Jan. 31, 2013).

3 Petition for the Determination of Nonregulated Status for Dicamba and Glufosinate-Tolerant Cotton MON 88701, Monsanto 

Petition Number: 12-CT-244U (July 2, 2012); Petitioner’s Environmental Report for Dicamba and Glufosinate-Tolerant Cotton 

MON 88701, Monsanto Petition Number: 12-CT-244U-S (USDA Petition #12-185-01p_al) (May 6, 2013).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 17 of 946

soybean and DGT cotton with other biotechnology-derived soybean and cotton that has been 

granted nonregulated status under 7 CFR Part 340. 

I.B.2. FDA Authority

The FDA regulates GE organisms under the authority of the FFDCA. The FDA is responsible for 

ensuring the safety and proper labeling of all plant-derived foods and feeds, including those 

developed through genetic engineering such as DT soybean and DGT cotton. All foods and feeds, 

whether imported or domestic and whether derived from plants modified by conventional breeding 

techniques or by genetic engineering techniques, must meet the same rigorous safety standards. 

Under the FFDCA, food and feed manufacturers are responsible for ensuring that the products they 

market are safe and properly labeled. In addition, the FDA must approve the use of any food 

additives, including those introduced into food or feed through plant breeding, before marketing. 

To help developers of GE plants that can used for food and feed comply with their obligations 

under the FFDCA, the FDA encourages them to participate in a voluntary, pre-market consultation 

process. In that process, developers submit to FDA a summary of data and information that 

provide the basis for a conclusion that a food and feed derived from GE plants is as safe as 

comparable non-GE food in the food supply. The goal of the consultation process is to ensure that 

human food and animal feed safety issues or other regulatory issues (e.g., labeling) are resolved prior 

to commercial distribution of food or feed derived from GE plants. 

Monsanto completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DT soybean on October 11, 2011 (BNF No. 

00125, Monsanto, 2011). As part of its evaluation, the FDA reviewed information on the identity, 

function, and characterization of the genes, including expression of the gene products in DT 

soybean, as well as information on the safety of the dicamba monooxygenase (DMO) protein and 

DT soybean itself, including a dietary risk assessment. Monsanto also submitted a summary of its 

safety and nutritional assessment of genetically engineered DGT cotton to FDA on April 6, 2012, 

and supplemented its submission with additional information on May 22, July 18, and September 10, 

2012. The FDA issued its Biotechnology Consultation Agency Response Letter on April 24, 2013, 

finalizing the consultation (BNF No. 000135, Monsanto, 2013). As part of its evaluation, the FDA 

reviewed information on the identity, function, and characterization of the genes, including 

expression of the gene products in DGT cotton, as well as information on the safety of the DMO 

protein and DGT cotton, including a dietary risk assessment (BNF No. 000135, Monsanto, 2013).

I.B.3. EPA Authority 

EPA regulates under FIFRA the pesticides (including herbicides) that are used with crops, including

GE herbicide-tolerant crops like DT soybean and DGT cotton. FIFRA requires all pesticides to be 

registered before distribution or sale, unless they are exempted. Under FIFRA, EPA must approve 

each distinct pesticide product, each distinct use pattern, and each distinct use site. Each crop for 

example, consititues a unique use site and no registered pesticide may be applied to any crop unless 

EPA has approved that specific pesticide/crop use. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 18 of 946

Each pesticide must be labeled with enforceable directions for use on a crop by crop basis. It is a 

violation of FIFRA to use any registered pesticide in a manner inconsistent with its labeling, subject 

to criminal and civil penalty. 4 For that reason, an approved herbicide cannot be lawfully used on a 

corresponding herbicide-tolerant crop, unless EPA approves a label amendment for such use.

Before EPA can approve any pesticide registration or label amendment, EPA must determine there 

will be no “unreasonable adverse effects on humans and the environment.” Bates v. Dow Agrosciences 

L.L.C., 544 U.S. 431, 438 (2005). In addition, if EPA finds that an approved herbicide use presents 

“unreasonable hazard to ... species declared endangered or threatened by the [Endangered Species 

Act],” EPA may immediately suspend the pesticide’s registration. 7 U.S.C. §§136(l), 136d(c). In 

deciding whether to register a pesticide, EPA also analyzes whether consulation under §7 of the ESA 

is warranted. See generally See Wash. Toxics Coal. v. EPA, 413 F.3d 1024, 1031-34 (9th Cir. 2005).

In addition to EPA’s FIFRA authority, EPA also regulates potential human-health impacts from 

pesticides under the FFDCA. EPA does so by establishing “tolerance levels” (i.e., “the amount of 

pesticide that may remain on food products”) under the FFDCA. CropLife Am. v. EPA, 329 F.3d 

876, 879 (D.C. Cir. 2003). The FFDCA “defines pesticide tolerances as ‘safe’ when there is ‘a 

reasonable certainty that no harm will result from aggregate exposure to the pesticide chemical 

residue.’” Id. (quoting 21 U.S.C. §346a(b)(2)(A)(ii)). 

In summary, in order to approve any use of a herbicide EPA must conclude that the herbicide, when 

used according to the label, does not pose an unreasonable adverse effect to humans or the 

environment, and, in order to establish a tolerance for the use of a herbicide on a food or feed crop, 

find there is a reasonable certainty of no harm to human health from non-occupational (food, water 

and residential/recreational) exposures to the herbicide. Therefore, all herbicides approved for use

in soybean and cotton production can be used safely, and do not pose an unreasonable risk to 

humans or the environment. 

In 2010, Monsanto has submitted to an application to amend Registration Number 524-582 to 

register a new use pattern for dicamba on DT soybean that facilitates a wider window of application, 

allowing dicamba to be applied pre-emergence through crop emergence and in-crop post-emergence 

through the early R1 reproductive phase, subject to a number of application requirements on the 

proposed label, which is currently pending before EPA, and the establishment of new tolerances for 

dicamba in soybean forage and hay. EPA has reviewed the safety of dicamba and the primary 

metabolite of dicamba (3.6-dichlorosalicylic acid or “DCSA”), during the reregistration of dicamba 

in 2006. EPA concluded in the 2006 dicamba Reregistration Eligibility Decision (RED) document 

that risks to human health and the environment associated with exposure to dicamba and its 

metabolites, including DCSA, were below the Agency’s level of concern for all registered uses of 

dicamba, including conventional soybean (U.S. EPA 2009d). 

Monsanto has also submitted (in July 2012) an amendment to its dicamba label to register a new use 

pattern for dicamba on DGT cotton that facilitates a wider window of application by removing all 

existing preemergence planting restrictions and allowing in-crop postemergence applications 

 

4 FIFRA §12(a)(2)(G) and §14
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 19 of 946

through seven days prior to harvest. This application also requests the establishment of a tolerance 

for cotton gin by-products, and the inclusion of DCSA in the residue definitions for both 

cottonseed and gin by-products.

The use pattern and rate of glufosinate on DGT cotton will follow the existing glufosinate-tolerant 

cotton uses outlined on the glufosinate herbicide label. The glufosinate residues in DGT cotton 

treated with commercial glufosinate rates are below the established pesticide residue tolerances for 

both cottonseed and gin by-products. Currently, glufosinate is undergoing registration review at 

EPA, which is expected to conclude by the end of 2013. It is expected that EPA will affirm the 

continued use of glufinsate in the marketplace upon completion of the registration review process. 

Therefore, Monsanto will not seek any changes in the glufosinate label or the established tolerances 

for its use on DGT cotton.

I.B.4. Center for Food Safety v. Vilsack and APHIS’s Regulatory Authority

On May 16, 2013, APHIS announced its intention to prepare a full Environmental Impact 

Statement (EIS) not only to address jurisdictional plant pest issues under the PPA, but also to 

examine the possible environmental impacts of dicamba herbicide uses, including the selection of 

herbicide-resistant weeds.5 The PPA does not give APHIS regulatory authority over herbicide uses. 

Indeed, Congress has expressly transferred regulatory authority over herbicides from APHIS to EPA 

over four decades ago, and APHIS itself has long recognized the strict limits on its PPA authority.6 

EPA’s authority to regulate herbicides under FIFRA includes an evaluation of, and measures to 

address, the development of herbicide resistance in weeds associated with the use of those 

products.7 Further, EPA’s review under FIFRA has been held to be the “functional equivalent” of 

NEPA review by multiple federal courts.8 Accordingly, APHIS has no jurisdiction over herbicides 

or the development of herbicide resistance in weeds that may be associated with herbicide use, and 

no authority to consider herbicide impacts under the PPA. Nor does APHIS have any obligation 

under NEPA to consider the environmental impacts of dicamba or glufosinate use, or alternatives to 

 

5 78 Fed. Reg. 28796.

6 Ruckelshaus v. Monsanto Co., 467 U.S. 986, 991(1984) (observing that “the Department of Agriculture’s FIFRA responsibilities 

were transferred to the then newly created Environmental Protection Agency....”); see also Pub.L. No. 92-516, 86 Stat. 973 

(1972).

7 See, e.g., EPA, Pesticide Registration (PR) Notice 2001-5, “Guidance for Pesticide Registrants on Pesticide Resistance 

Management Labeling,” p. 2 (2001), available at http://www.epa.gov/PR_Notices/pr2001-5.pdf (labeling measures to assist in 

pesticide resistance management). Additionally, pesticide registrants must report resistance to EPA as an adverse effect in order 

to ensure the pesticide continues to meet FIFRA requirements for registration. 40 C.F.R. § 159.188(c).

8 Envtl. Def. Fund, Inc. v EPA, 489 F.2d 1247, 1256 (D.C. Cir. 1973) (holding that FIFRA’s standard and processes are the 

“functional equivalent of a NEPA investigation” and that “[t]he law requires no more”); Envtl. Def. Fund, Inc. v. Blum, 458 F. 

Supp. 650, 662 n.6 (D.D.C. 1978) (“If the ‘functional equivalent’ requirement means anything, it surely means that the EPA [in 

conducting analysis under FIFRA] did not have to follow the detailed procedural requirements laid out by NEPA.”); Douglas 

Cnty. v. Babbitt, 48 F.3d 1495, 1502-03 (9th Cir. 1995) (“FIFRA procedures ... displace[] NEPA’s procedural and informational 

requirements” because “Congress did not intend for NEPA to apply to FIFRA.”); Merrell v. Thomas, 807 F.2d 776, 782 (9th Cir. 

1986) (“FIFRA’s review provisions do afford the public some opportunity to participate in pesticide registration decisions.... 

[And while that] opportunity would be greater if NEPA [also] applied[,] Congress has made its choice [not to do so].”). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 20 of 946

deregulation since there is no reasonable alternative to deregulation once APHIS finds DT soybean 

and DGT cotton do not pose a pose a greater plant pest risk than their conventional counterparts.

9

 

The Ninth Circuit recently addressed APHIS’ authority under the PPA in Center for Food Safety v. 

Vilsack and concluded that APHIS does not have authority to regulate herbicide issues pertaining to 

GE crops.10 That case involved a challenge to the Record of Decision (ROD) and supporting EIS

APHIS issued unconditionally deregulating Roundup Ready® Alfalfa (RRA) on the ground that 

RRA was not a “plant pest” within the meaning of the PPA.11 This litigation has a lengthy history.

That ROD and EIS were prepared as a result of prior litigation, which resulted in APHIS’s initial 

deregulation of RRA being vacated. Monsanto and Forage Genetics filed a petition in April 2004 

seeking a determination that RRA is not a plant pest.12 In response to the petition, APHIS 

considered whether RRA caused any plant pest harms and concluded that RRA is not a plant pest, 

and therefore should not be regulated.13 APHIS also prepared an Environmental Assessment (EA) 

under NEPA and issued a Finding of No Significant Impact (FONSI).14 The agency accordingly did 

not prepare an Environmental Impact Statement (EIS) in support of its initial deregulation decision. 

On June 14, 2005, APHIS unconditionally deregulated RRA.

Plaintiffs sued the agency in the United States District Court for the Northern District of California 

to challenge the June 2005 deregulation, contending that APHIS violated the PPA, the Endangered 

Species Act (ESA), and NEPA.15 The district court initially found APHIS’s initial deregulation 

violated NEPA, vacated that deregulation, and enjoined APHIS from deregulating RRA in any 

manner, and any further planting of RRA, pending completion of an EIS addressing the 

environmental effects of gene flow, glyphosate-resistant weeds, and other potential issues.16 The 

Ninth Circuit affirmed the district court’s order.17 The Supreme Court, however, granted certiorari 

 

9 DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an agency has no ability to prevent a certain effect due to its limited 

statutory authority over the relevant actions, the agency cannot be considered a legally relevant “cause” of the effect, and is 

therefore not required to analyze the environmental impact of an action it could not refuse to perform).

10 718 F.3d 829, 832-33 (9th Cir. 2013).

11 Id. at 832.

12 See 70 Fed. Reg. 36917.

13 Id. at 36917-18.

14 Id. at 36919.

15 Geertson Seed Farms v. Johanns, No. C06-01075, 2007 U.S. Dist. LEXIS 14533 at *10-12 (N.D. Cal. Feb. 13, 2007). 

16 Geertson Seed Farms v. Johanns, 2007 U.S. Dist. LEXIS 21491 at *2-3 (N.D. Cal. Mar. 12, 2007); Geertson Farms v. Johanns, 2007 U.S. 

Dist. LEXIS 32701 at *9 (N.D. Cal. May 3, 2007). 

17 Geertson Seed Farms v. Johanns, 570 F.3d 1130, 1133-34 (9th Cir. 2009). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 21 of 946

and reversed, and remanded, holding that the injunction prohibiting partial deregulation and/or 

further RRA planting was an abuse of discretion and must be dissolved in its entirety.

18

 

APHIS released its final EIS for RRA in December 2010. APHIS explained in the ROD that it was 

required under the PPA to deregulate RRA because RRA was not a plant pest and APHIS 

accordingly lacked authority to continue to regulate it as such.

Plaintiffs then filed another action in U.S. District Court for the Northern District of California,

challenging APHIS’s 2011 unconditional deregulation of RRA.19 The district court rejected 

plaintiffs’ challenges entirely. The court held that the alleged impacts of gene flow from GE crops 

and increased glyphosate usage are not plant pest harms under the PPA.20 Once APHIS correctly 

concluded that it no longer had jurisdiction to regulate RRA as a plant pest, the regulation of RRA 

was a nondiscretionary act that did not obligate the agency to consult with the U.S. Fish and Wildlife 

Service (USFWS) under the ESA regarding the potential impacts on threatened and endangered 

species from glyphosate use.21 The district court held that APHIS’ EIS satisfied NEPA’s procedural 

requirements and entered summary judgment in favor of defendants on all claims.22 Plaintiffs 

appealed to the Ninth Circuit, challenging the district court’s conclusion that gene flow and the 

impacts associated with increased herbicide use are not plant pest harms under the PPA, and that 

RRA was therefore not a “plant pest” within the agency’s regulatory jurisdiction.23 The Ninth 

Circuit unanimously affirmed the district court’s ruling, concluding that the PPA does not regulate 

the types of alleged harms of which the plaintiffs complained.24 Plaintiffs sought rehearing and 

rehearing en banc, but their petition was denied. 

Specifically, the Ninth Circuit concurred with the Government’s position that APHIS does not have 

general authority over agricultural issues, and instead only possesses specific, narrow authority to 

reduce the risk of dissemination of plant pests or noxious weeds.25 The Ninth Circuit also agreed 

with the Government that risks from herbicide uses do not constitute plant pest risks because 

herbicide use does not result from the GE organism itself, but instead from independent human 

action.26 Indeed, the Court specifically held that APHIS “has ... never considered the possible 

consequences associated with increased herbicide use, including creation of herbicide-resistant 

 

18 Monsanto Co. v. Geertson Seed Farms, 130 S. Ct. 2743, 2761-62, 177 L. Ed. 2d 461 (2010). 

19 Ctr. for Food Safety v. Vilsack, 844 F. Supp. 2d 1006 (N.D. Cal. Jan. 5, 2012).

20 Id. at 1017.

21 Id. at 1020-21.

22 Id. at 1024-25.

23 Ctr. for Food Safety v. Vilsack, 718 F.3d at 839.

24 Id. at 832.

25 Id. at 834-35.

26 Id.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 22 of 946

weeds, to be ‘plant pest’ injuries,” and that APHIS’s interpretation is “the best interpretation of this 

particular statutory language.”27 Accordingly, the Ninth Circuit held that APHIS has no regulatory 

authority or discretion to deny the petition for nonregulated status because of alleged herbicide 

impacts or harms.

28

 

Because the Ninth Circuit upheld APHIS’ determination that RRA is not a plant pest under the 

meaning of the term in the PPA and the accompanying regulations, APHIS no longer had 

jurisdiction to regulate RRA, and accordingly had no obligation to consult with the USFWS under 

the Endangered Species Act (ESA) or to consider the effects of glyphosate use in RRA or other 

glyphosate tolerant crops in its EIS. Nor did APHIS have an obligation to consider alternatives to 

unconditional regulation under NEPA because APHIS’s limited plant-pest authority denied APHIS 

any discretion to continue regulating RRA as a plant pest. 

Likewise, APHIS has no obligation here under NEPA to prepare an EIS to consider the potential 

environmental impacts of dicamba (or glufosinate) use on DT soybean or DGT cotton crops 

because APHIS lacks authority (and hence discretion) to regulate herbicide uses under the PPA or 

other APHIS authority. Monsanto is nevertheless including a limited discussion of herbicide use and 

effects in this Environmental Report and its Appendices to address statements made and questions 

raised by APHIS about herbicide uses in its May 2013 Notice of Intent (NOI), even though 

Monsanto believes the NOI seeks information beyond the scope of APHIS’ statutory authority 

under the PPA.

I.B.5. Threatened and Endangered Species 

Section 7(a)(2) of the ESA requires that the Federal action agency, in consultation with the USFWS 

or the National Marine Fisheries Service (NMFS), ensure that any discretionary action the agency 

authorizes, funds, or carries out is not likely to jeopardize the continued existence of a listed species 

or result in the destruction or adverse modification of designated critical habitat. A species is added 

to the list of threatened and endangered plant and wildlife species when the USFWS/NMFS 

determines that it is threatened or endangered because of any of the following factors: the present or 

threatened destruction, modification, or curtailment of its habitat or range; overutilization for 

commercial, recreational, scientific, or educational purposes; disease or predation; the inadequacy of 

existing regulatory mechanisms; and the natural or manmade factors affecting its survival. Once an 

animal or plant is added to the list, protective measures under the ESA apply to the species and its 

habitat—including protection from adverse effects of discretionary Federal activities. The agency 

taking the discretionary action must assess the effects of its action and consult with the USFWS or 

NMFS if it determines the action “may affect” listed species or critical habitat.

APHIS’ regulatory authority over certain GE organisms under the PPA is limited to those GE 

organisms which it has reason to believe might be a plant pest or those for which APHIS does not 

have sufficient information to determine that the GE organism is unlikely to pose a plant pest risk. 

APHIS does not have statutory authority to authorize or regulate the use of herbicides. Instead, 

 

27 Alfalfa II, 2013 U.S. App. LEXIS 9920, at *29-30 (9th Cir. May 17, 2013). 

28 Id.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 23 of 946

EPA has the sole authority to regulate the use of any herbicide, including dicamba, glufosinate, and 

glyphosate. APHIS’ ESA responsibilities thus are limited to ensuring that the plant for which 

nonregulated status is sought (here, DT soybean and DGT cotton) will not itself affect listed species 

or critical habitat. 

As part of the NEPA process, APHIS met with USFWS officials on June 15, 2011, to discuss 

whether APHIS has any obligations under the ESA to analyze the impacts of herbicide use 

associated with all GE crops on threatened and endangered species (TES). As a result of those

discussions, the USFWS and APHIS agreed that it is not necessary for APHIS to perform an ESA 

effects analysis on herbicide use associated with GE crops. Again, EPA has the sole authority to 

authorize or regulate the use of dicamba, or any other herbicide, by growers. Under 7 CFR Part 340, 

APHIS only has the authority to regulate GE organisms if the agency believes the organism may 

pose a plant pest risk. The Ninth Circuit in Center for Food Safety v. Vilsack confirmed this point 

specifically regarding herbicide uses, concluding that the ESA’s consultation duty is triggered only 

when the agency has authority to take action and discretion to decide what action to take.29 In that 

case, APHIS had reached an ESA “no effect” conclusion as to the plant specifically, which was not 

challenged. The plaintiffs contended however that APHIS was required to perform an ESA 

consultation as to the herbicide. But APHIS lacked authority over the herbicide uses. Once APHIS 

concluded that RRA was not a plant pest, the agency had no jurisdiction to continue regulating the 

crop as a plant pest.30 The agency’s deregulation of RRA was thus a nondiscretionary act that did 

not trigger the agency’s duty to consult under the ESA regarding herbicide uses.31 In this instance, 

APHIS has no obligation under NEPA or the ESA to consider the effects on TES of herbicide use 

associated with DT soybean or DGT cotton crops. Nor does APHIS have an obligation to consult 

with the USFWS under the ESA given that the GE crops do not constitute plant pest risks. 

In this Environmental Report, Monsanto has supplied information demonstrating that the biology 

of DT soybean and DGT cotton and the agricultural practices associated with their cultivation will 

have no impacts on TES and their critical habitats. 32 Additionally, though not required by law, 

Monsanto has provided in Appendix F information also available to the EPA in the context of the 

dicamba herbicide that addresses the potential indirect effects of dicamba application on TES 

associated with either the introduction or non-introduction of DT soybean and DGT cotton. 

 

29 Ctr. for Food Safety v. Vilsack, 718 F.3d at 842.

30 Id. 

31 Id.

32 Petition for the Determination of Nonregulated Status for Dicamba-Tolerant Soybean MON 87708, Monsanto Petition 

Number: 10-SY-201U (July 6, 2010); Petitioner’s Environmental Report for Dicamba and Glufosinate-Tolerant Cotton MON 

88701, Monsanto Petition Number: 12-CT-244U-S (USDA Petition #12-185-01p_al) (May 6, 2013).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 24 of 946

I.C. PURPOSE AND NEED FOR APHIS ACTION

The National Environmental Policy Act (NEPA) requires federal agencies to examine the potential 

environmental impacts of any proposed major federal action that may significantly affect the quality 

of the human environment. The federal action being considered here is the potential deregulation 

of DT soybean and DGT cotton. These products provide improved weed management options in 

soybean and cotton cultivation to control a broad spectrum of grass and broadleaf weed species. 

These uses of dicamba and glufosinate also provide effective control of herbicide resistant weeds 

that have arisen in certain areas of the U.S. which are impacting both conventional and existing GE 

crops. Existing GE crops have provided enormous benefits to farmers in recent decades, including 

improved yields, lower costs, decreased emissions from farm equipment, increased use of 

conservation tillage and associated environmental benefits, and the ability to use herbicides with a 

more benign human health and environmental profile. These new soybean and cotton GE crop 

products will provide another tool for farmers in certain areas of the U.S. who are encountering 

weed resistance and other weed management challenges, but seek to maintain yield and quality while 

using established production practices and conservation tillage.

Under the authority of the plant pest provisions of the PPA and 7 CFR Part 340, APHIS has issued 

regulations for the safe development and use of GE organisms. Any party can petition APHIS to 

deregulate an organism that is regulated under 7 CFR Part 340 by documenting the evidence that the 

GE organism is unlikely to pose a greater plant pest risk than the unmodified organism from which 

it was derived. As required by 7 CFR § 340.6, APHIS must respond to a petitioner that requests a 

determination of the regulated status of GE organisms, including GE plants such as DT soybean 

and DGT cotton. To do so, APHIS must conduct a Plant Pest Risk Assessment (PPRA) to 

determine whether the GE organism is likely to pose a plant pest risk. If APHIS concludes that the 

GE organism is unlikely to pose a plant pest risk, APHIS must grant the petition for nonregulated 

status, and the GE organism is no longer subject to the plant pest provisions of the PPA and 7 CFR 

Part 340. Here, APHIS must respond to the July 2010 petition from Monsanto requesting a 

determination of nonregulated status of DT soybean, and the July 2012 petition from Monsanto 

requesting a determination of nonregulated status of DGT cotton.

I.D. SCOPING FOR THE ENVIRONMENTAL REPORT

Public scoping is required under NEPA, as amended, Council on Environmental Quality (CEQ) 

regulations for implementing NEPA, the USDA regulations implementing NEPA, and the APHIS 

Implementing Procedures. Scoping for this environmental report began on May 16, 2013, when 

APHIS gave notice in the Federal Register (78 Fed. Reg. 28796-28798) of its intent to prepare a 

draft EIS. 

The Federal Register notice solicited public involvement in the form of written comments regarding 

the above issues and alternatives for regulatory action. Written comments were accepted from the 

public during a comment period, which lasted until June 17, 2013. 

Critically, all of the issues on which APHIS solicited comment relate to the herbicide—and not to 

the plants (DT soybean and DGT cotton) for which Monsanto has sought nonregulated status from 

APHIS. As discussed above, Congress transferred regulatory authority over herbicides from APHIS 

to EPA. Accordingly, APHIS has no jurisdiction over herbicides or herbicide resistance, and no 

authority to consider herbicide impacts under the PPA. Monsanto believes that APHIS has no legal 

obligation under NEPA to consider herbicide impacts or herbicide resistance in any Environmental 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 25 of 946

Impact Statement or Environmental Assessment. See DOT v. Public Citizen, 541 U.S. 752, 770, 769 

(2004) (where an agency has no ability to prevent a certain effect due to its limited statutory 

authority over the relevant actions, the agency cannot be considered a legally relevant “cause” of the 

effect, and is therefore not required to analyze the environmental impact of an action it could not 

refuse to perform). See also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 

9920, at *16-17 (9th Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not 

exhibit any risk of plant pest harm, APHIS must deregulate it since the agency does not have 

jurisdiction to regulate organisms that are not plant pests.”). Nonetheless, because APHIS has 

announced its intention to address these herbicide-related issues in an Environmental Impact 

Statement, this Environmental Report similarly includes discussion of these issues. In addition, 

however, this report also addresses the key questions posed by the petitions for nonregulated status 

that are within APHIS’ jurisdiction, i.e., issues specifically related to potential plant pest risks or 

impacts, as well as issues related to potential impacts on agricultural production of soybeans and 

cotton, socioeconomic impacts and potential impacts on biological resources.

The alternatives that are discussed in Section III and analyzed in this Environmental Report result 

directly from this scoping effort. 

II. AFFECTED ENVIRONMENT

II.A. INTRODUCTION

For the purpose of this environmental report, the affected environment for DT soybean and DGT 

cotton grown in the United States is described in the context of the production practices used to 

farm and process soybean and cotton, specifically the practices related to, among other things, pest 

management (including weed control) and the genetic environment that could potentially be 

influenced by gene flow from DT soybean and DGT cotton. These practices and conditions are 

described in this chapter to set the stage for the chapter IV (Environmental Consequences) 

discussion of how the different action alternatives may change activities and potentially have impacts 

on the human environment. The production practices under each alternative also determine how 

the various “resource areas” of the affected environment are affected by the decisions of growers 

and producers. Those resource areas have been grouped into the physical environment (land use, 

soil, water, air quality, and climate change), biological resources (wildlife and ecosystems), human 

health, animal health, and socioeconomics. 

As discussed elsewhere in this report, Congress transferred regulatory authority over herbicides from 

USDA to EPA several decades ago. Accordingly, USDA-APHIS has no jurisdiction over herbicides 

or herbicide resistance, and no authority to consider herbicide impacts under the PPA. Nonetheless, 

because APHIS indicated in its Notice of Intent to Prepare an Environmental Impact Statement (78 

Fed. Reg. 28796, May 16, 2013) that it would be considering herbicide effects and herbicide 

resistance as part of the NEPA process, Monsanto has included a limited discussion of herbicide 

impacts in the following sections and has provided detailed herbicide information in an Appendix to 

this report. Importantly, however, Monsanto believes that APHIS has no legal obligation under 

NEPA to consider herbicide impacts or herbicide resistance in any Environmental Impact Statement 

or Environmental Assessment. See DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an 

agency has no ability to prevent a certain effect due to its limited statutory authority over the 

relevant actions, the agency cannot be considered a legally relevant “cause” of the effect, and is 

therefore not required to analyze the environmental impact of an action it could not refuse to 

perform). See also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 26 of 946

*16-17 (9th Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not exhibit any 

risk of plant pest harm, APHIS must deregulate it since the agency does not have jurisdiction to 

regulate organisms that are not plant pests.”).

This chapter is organized into six main sections, as follows:

Section II.B, Agricultural Production of Soybean & Cotton, describes how soybean and cotton are farmed, 

including an overview of how the crops are used (e.g., food, feed, fiber). Section II.B also discusses 

weed management practices in soybean and cotton farming because the DT and DGT traits may 

influence weed management options. 

Section II.C, Physical Environment, describes how soybean and cotton farming practices (e.g., tillage 

and herbicide usage) impact land uses, and how they interact with soil, air, and water bodies.

Section II.D, Biological Resources, describes how soybean and cotton, and the practices related to 

soybean and cotton production, interact with living organisms in ecological and agricultural settings. 

The biological resources are divided into animal communities, plant communities, and 

microorganisms. Section II.D also discusses gene flow and weediness, including the potential for 

hybridization with cultivated soybean and cotton plants, as well as with feral species. Section II.D 

also considers the potential impacts on adjacent agricultural crops and non-agricultural plants from

the offsite movement of herbicides.

Section II.E, Human Health, describes both consumer and worker health and safety with respect to 

the production and use of soybean, cotton, and related products, and the use of pesticides that are 

applied before or during the production of soybean and cotton. Section II.E. addresses the direct 

ingestion of the products of soybean and cotton, such as cooking oils, food additives, and nutritional 

supplements, as well as the potential for inhalation of cotton dust by workers during cotton handling 

and processing.

Section II.F, Animal Health, describes the use of soybean, cotton, and derivative products in animal 

agriculture, and in particular in the animal feed industry. Section II.F also describes the 

biotechnology consultation process with FDA for soybean and cotton, and the dicamba tolerance 

assessment of the dicamba herbicide conducted by EPA.

Section II.G, Socioeconomics, describes the domestic economic environments of soybean and cotton, 

the trade economic environments of soybean and cotton, and public perceptions regarding 

genetically modified ingredients in food. These markets are described from seed to consumer. 

II.B. AGRICULTURAL PRODUCTION OF SOYBEANS & COTTON

II.B.1. Agricultural Production of Soybeans

II.B.1.a. Crop Use and Biology

Soybean: Soybean belongs to the genus Glycine, which has approximately nine species, with 

commercial soybean (G. max) being placed in the subgenus Soja along with one other species, G. 

soja. G. max is sexually compatible only with G. soja and no other Glycine species. Wild soybean 

species are endemic throughout much of Asia, but do not exist naturally in North America (OECD 

2000b). G. max is the only Glycine species located in the United States. G. soja is found in China, 
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Taiwan, Japan, Korea, and Russia and can hybridize naturally with the cultivated soybean, G. max

(Hymowitz 2004; Lu 2004).

Soybean Biology: Soybean is a “short day plant”, meaning it flowers more quickly when day length 

is shorter. As a result, day length is important in determining areas of cultivar adaptation. Soybean 

cultivars are identified based on bands of adaptation (maturity groups) that run east-west, 

determined by latitude and day length. In the Americas north of the equator, there are 13 maturity 

groups (MG), from MG 000 at approximately 45 degrees latitude to MG X near the equator (OECD 

2000b).

The soybean plant is a member of the legume family like alfalfa and clover and fixes a significant 

portion of its own nitrogen through the symbiotic relationship with the nitrogen-fixing 

Bradyrhizobia bacteria (Bradyrhizobium japonicum) that live in the nodules on its roots. Bradyrhizobia 

are unicellar, microscopic bacteria that invade the soybean plant through its root hairs (Hoeft, et al. 

2000a; b). The plant responds to this invasion by forming nodules which contain colonies of 

bacteria. Once established on the soybean root, bacteria in the nodule take gaseous nitrogen from 

the atmosphere and fix it in forms easily used by the soybean plant. These bacteria can provide up to 

50% of nitrogen needed by soybean (Pedersen 2007).

Soybean is considered a self-pollinating species, propagated commercially by seed. The anthers 

mature in the bud and directly pollinate the stigma of the same flower (OECD 2000b). Cross 

pollination is very rare, usually less than one percent (Caviness 1966).

The soybean plant is not weedy in character and in North America is not found outside of 

cultivation (OECD 2000b).

Soybean Use: Soybean is grown as a commercial crop in over 35 countries and is one of the most 

valued agricultural commodities because of its high protein and oil content. In 2011, soybean 

represented 56% of world oilseed production (ASA 2012), and approximately 41% of those 

soybeans were produced in the U.S. (USDA-FAS 2013a). 

Approximately 95% of the world’s soybean seed supply was crushed to produce soybean meal and 

oil in 2011 (Soyatech 2013), and the majority was used to supply the feed industry for livestock use 

or the food industry for edible vegetable oil and soybean protein isolates.

II.B.1.b. Land Use

Soybean Production: The productivity of soybean is highly dependent upon soil and climatic 

conditions. In the U.S., the soil and climatic requirements for growing soybean are very similar to 

corn. Planted acres by county are shown in Figure II.B-1. The soils and climate in the Midwestern, 

Eastern, and portions of the Great Plains regions of the U.S. provide sufficient water under normal 

climatic conditions to produce a soybean crop. 

The U.S. soybean acreage in the past thirteen years has varied from approximately 64.7 to 77.5

million acres, with the lowest acreage recorded in 2007 and the highest in 2009 (Table II.B-1). 

Average soybean yields have varied from 33.9 to 44.0 bushels per acre over this same time period. 

Annual soybean production ranged from 2.5-3.4 billion bushels over the past thirteen years. 

According to data from USDA-NASS (2013b), soybean was planted on approximately 77.2 million 

acres in the U.S. in 2012, producing 3.0 billion bushels of soybean (Table II.B-1). 
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In 2013, 93% of soybean planted in the U.S. was genetically engineered (GE) to be herbicide 

tolerant. USDA listed no other types of GE soybean (USDA-ERS 2013). There is no indication 

that the introduction and widespread adoption of GE-derived crops in general has resulted in a 

significant change to the total U.S. acreage devoted to agricultural production. The cumulative land 

area in the U.S. planted to principal crops, which include corn, sorghum, oats, barley, winter wheat, 

rye, durum, spring wheat, rice, soybean, peanuts, sunflower, cotton, dry edible beans, potatoes, 

canola, proso millet, and sugar beets, has remained relatively constant over the past 27 years. From 

1982 to 1995, the average yearly acreage of principal crops was 323 million. This average is 

essentially unchanged at 326 million acres since the introduction of GE-derived crops in 1996 

(USDA-NASS 1984; 1990; 1992; 1995; 1998; 2000; 2003; 2006). 

For purposes of this discussion, soybean production is divided into four major soybean growing 

regions: Midwest region (IL, IN, IA, KS, KY, MI, MN, MO, NE, ND, OH, SD, and WI), Southeast 

region (AL, AR, FL, GA, LA, MS, NC, SC, and TN), Eastern Coastal region (DE, MD, NJ, NY, PA, 

VA, and WV), and Plains region (OK and TX) (Table II.B.-2). The vast majority of soybean was 

grown in the Midwest region, representing 83.3% of the total U.S. acreage. The Southeast, Eastern 

Coastal, and Plains regions represented 13.1%, 92.9%, and 0.7% of the acreage, respectively. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 29 of 946

Figure II.B-1. Planted Soybean Acres by County in the U.S. in 2012.

Source: (USDA-NASS 2012f).
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Table II.B-1 Soybean Production in the U.S., 1999 – 20121

Year

Acres 

Planted

(×1000)

Acres 

Harvested

(×1000)

Average

Yield

(bushels/acre)

Total

Production

(×1000 bushels)

Value

(billions $)

2012 77,198 76,104 39.6 3,014,998 43.19

2011 75,046 73,776 41.9 3,093,524 38.50

2010 77,404 76,610 43.5 3,329,181 37.55

2009 77,451 76,372 44.0 3,359,011 32.15

2008 75,718 74,681 39.7 2,967,007 29.46

2007 64,741 64,146 41.7 2,677,117 26.97

2006 75,522 74,602 42.9 3,196,726 20.47

2005 72,032 71,251 43.1 3,068,342 17.30

2004 75,208 73,958 42.2 3,123,790 17.90

2003 73,404 72,476 33.9 2,453,845 18.02

2002 73,963 72,497 38.0 2,756,147 15.25

2001 74,075 72,975 39.6 2,890,682 12.61

2000 74,266 72,408 38.1 2,757,810 12.47

Ave. 74,310 73,220 40.6 2,976,014 24.76

1

Source is (USDA-NASS 2012f)
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Table II.B-2. U.S. Soybean Production by Region and State in 20121

Region/State

Acres 

Planted

(thousands)

Acres 

Harvested

(thousands)

Average Yield

(bushels/acre)

Total Production

(×1000 bushels)

Value

(billions $)

Midwest Region

Illinois 9,050 8,920 43.0 383,560 5.60

Indiana 5,150 5,140 43.5 223,590 3.26

Iowa 9,350 9,300 44.5 413,850 5.92

Kansas 4,000 3,810 22.0 83,820 1.20

Kentucky 1,480 1,470 40.0 58,800 0.85

Michigan 2,000 1,990 43.0 85,570 1.20

Minnesota 7,050 6,990 43.0 300,570 4.27

Missouri 5,400 5,260 29.5 155,170 2.25

Nebraska 5,050 4,990 41.5 207,085 2.90

North Dakota 4,750 4,730 34.0 160,820 2.28

Ohio 4,600 4,580 45.0 206,100 2.99

South Dakota 4,750 4,710 30.0 141,300 1.99

Wisconsin 1,710 1,700 41.5 70,550 0.98

Region Totals 64,340 63,590 39.2 2,490,785 35.69

Southeast Region

Alabama 340 335 45.0 15,075 0.22

Arkansas 3,200 3,160 43.0 135,880 1.96

Florida 21 20 39.0 780 0.01

Georgia 220 215 37.0 7,955 0.12

Louisiana 1,130 1,115 46.0 51,290 0.75

Mississippi 1,970 1,950 45.0 87,750 1.26

North Carolina 1,590 1,580 39.0 61,620 0.86

South Carolina 380 370 34.0 12,580 0.18

Tennessee 1,260 1,230 38.0 46,740 0.68

Region Totals 10,111 9,975 42.1 419,670 6.04

Eastern Coastal Region

Delaware 170 168 42.5 7,140 0.10

Maryland 480 475 47.0 22,325 0.32

New Jersey 96 94 39.0 3,666 0.05

New York 315 312 46.0 14,352 0.20

Pennsylvania 530 520 48.0 24,960 0.35

Virginia 590 580 42.0 24,360 0.33

West Virginia 21 20 49.0 980 0.01

Region Totals 2,202 2,169 45.1 97,783 1.36
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Table II.B-2 (continued). U.S. Soybean Production by Region and State in 2012 

Region/State

Acres Planted

(thousands)

Acres 

Harvested

(thousands)

Average Yield

(bushels/acre)

Total Production

(×1000 bushels)

Value

(billions $)

Plains Region

Oklahoma 420 260 15.0 3,900 0.06

Texas 125 110 26.0 2,860 0.04

Region Totals 545 370 18.3 6,760 0.10

U.S. Totals 77,198 76,104 39.6 3,014,998 43.19

1

Source: (USDA 2013).

Seed Production Areas: Soybean seed is produced throughout most of the U.S. soybean-growing 

regions by companies that produce and sell seed, and by toll seed producers, or tollers, which are 

companies that produce certified seed for other companies pursuant to a contract. Seeds for a given 

maturity group are produced within the same geographic area where they will be planted for 

commercial production. 

II.B.1.c. General Agronomic Practices

Below is a summary of information pertaining to the agronomic practices and management of 

soybean.

Life Cycle: Soybean is generally planted from early to mid-May and harvested in the fall. Soybean is 

photoperiod sensitive, which means that it transitions from vegetative to flowering stage in direct 

response to length of daylight (Scott and Aldrich 1970). Soybean can be harvested when the 

moisture content of the seed drops below 15%. (Scott and Aldrich 1970). Timely harvest when the 

moisture content is 13 to 14% also will minimize losses. 

Soybean is considered a self-pollinating species, propagated commercially by seed. The anthers 

mature in the bud and directly pollinate the stigma of the same flower (OECD 2000b). 

Varieties: Hundreds of soybean varieties are tested each year in performance trials conducted by 

universities and private companies in all the major soybean growing states. The following properties 

can typically be obtained from the results of variety trials, and considered by growers in variety 

selection: maturity group, disease resistance, insecticide seed treatment, yield, maturity date, percent 

lodging (plant fallen over on the ground), height, and herbicide resistance (Tylka, et al. 2010). In 

different parts of the country and/or in other trials, additional properties may be identified, such as 

iron deficiency tolerance or protein or oil content (Pedersen 2008b).

Water Use: The general water requirement for a high-yielding soybean crop is approximately 20 

inches of water during the growing season (Hoeft et al. 2000a; b). Soil texture and structure are key 

components determining water availability in soils, where medium-textured soils hold more water, 

allowing soybean roots to penetrate deeper in medium-textured soils than in clay soils. 

Supplemental irrigation is used on approximately 7% of U.S. soybean acreage, primarily in the 

western and southern soybean growing regions (USDA-NASS 2008b). The highest concentrations 

of irrigated soybeans are in the sandy soils of eastern Nebraska and the Mississippi River Delta 
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region of Arkansas and neighboring states (USDA-NASS 2009b). In 2006, an average of 8.4 inches 

of water per acre was applied to irrigated fields. Groundwater was the source for 92% of irrigated 

acres and surface water for the remainder (USDA-ERS 2012f).

Yields: Planting date has the greatest impact on yield, according to research conducted in the 

Northern states (Hoeft et al. 2000a; b). Highest yields are generally obtained when planting in early 

to mid-May. Yields begin to decline quite rapidly when planting is delayed until late May. Average 

U.S. soybean yields in the past ten years (2003 to 2012) have varied from 33.9 to 43.5 bushels per 

acre. Soybean production ranged from 2.45 to 3.36 billion bushels over the past ten years, with 2009 

being the largest production year on record. Soybean yield (39.6 bushels per acre) and production 

(3.0 billion bushels) in 2012 was down slightly from the record level in 2009, mainly as a result of 

drought conditions in the Midwest and South regions (USDA-NASS 2013b). Average crop yield on 

irrigated land was 51.4 bushels per acre (USDA-ERS 2012f).

Crop Nutrition: The three most important soil-supplied nutrients are nitrogen, phosphate, and 

potash. Other nutrients important for plant growth such as calcium, magnesium, iron, boron, 

manganese, zinc, copper, and molybdenum are needed at much lower concentrations and are 

limiting only in certain environments (Pedersen 2007). Approximately half the nitrogen need of 

soybean is obtained from the soil and half from the air (Pedersen 2007). One bushel of soybean 

contains approximately 4.0 lb of nitrogen, 0.8 lb of phosphate, and 1.4 lbs of potash (Purdue 

Extension 2012).

Crop Rotation: The well-established farming practice of crop rotation is a key management tool 

for soybean growers. The purposes of growing soybean in rotation include:

 improving yield and profitability of one or both crops over time;

 decreasing the need for nitrogen fertilizer on the crop following soybean;

 mitigating or breaking disease, insect, and weed cycles;

 improving soil tilth and soil physical properties;

 increasing residue cover;

 reducing soil erosion;

 increasing soil organic matter; and

 reducing runoff of nutrients, herbicides, and insecticides (Al-Kaisi, et al. 2003; 

Boerma, et al. 2004; Heatherly and Elmore 2004). 

According to USDA Economic Research Service, 95% of the soybean-planted acreage has been in 

some form of a crop rotation system since 1991 (USDA-ERS 2001). Corn- and wheat-planted 

acreage has been rotated at a slightly lower level of 75% and 70%, respectively. Although the 

benefits of crop rotations can be substantial, growers must make cropping decisions by evaluating 

agronomics, economic returns of various cropping systems, and other related factors. Crop 

rotations also afford growers the opportunity to diversify farm production in order to minimize 

market risks. 

Agronomic practices such as rotation patterns for soybean vary from state to state. However, there 

are similarities among states within certain growing regions. The majority of the U.S. soybean 
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acreage (68.6%) is rotated to corn, with approximately 14.5% of the soybean acreage rotated back to 

soybean the following year. Wheat follows soybean on approximately 11.2% of the U.S. soybean 

acreage.

Continuous soybean production is uncommon in the Midwest. Soybean extension specialists 

encourage growers to avoid the practice as a way to reduce the risk of damage from diseases and 

nematodes (Al-Kaisi et al. 2003; Hoeft et al. 2000a; b). Corn and soybean occupy more than 80% of 

the farmland in many of the Midwestern states, and the two-year cropping sequence of soybeancorn is used most extensively in this region. However, a soybean crop sometimes is grown after 

soybean and then rotated to corn in a 3-year rotation sequence (soybean-soybean-corn) in the 

Midwest. Compared to corn, soybean shows a greater yield response to being grown after a number 

of years without soybean. The yield of both corn and soybean is approximately 10% higher when 

grown in rotation than when either crop is grown continuously (Hoeft et al. 2000a; b). 

A combination of conservation tillage practices and crop rotation has been shown to be very 

effective in improving soil physical properties. Long-term studies in the Midwest indicate that the 

corn-soybean rotation improves yield potential of no-till systems compared to continuous corn 

production (Al-Kaisi 2001).

Soil Types: The productivity of soybean is highly dependent upon soil and climatic conditions. In 

the U.S., the soil and climatic requirements for growing soybean are very similar to corn. Soil 

texture and structure are key components determining water availability in soils, where mediumtextured soils hold more water, allowing soybean roots to penetrate deeper in medium-textured soils 

than in clay soils (USDA-ERS 2008).

Tillage: Tillage in soybean production systems is used to prepare a seedbed, address soil 

compaction, incorporate fertilizers and herbicides, manage water movement both within and out of 

a production field, and control weeds (CAST 2009), depending on tillage type. The benefits of 

conservation tillage or no-till systems relative to conventional tillage are well documented and 

include reduced soil erosion, reduced fuel and labor costs, conservation of soil moisture, 

improvement of soil structure, reduction of soil compaction and improvement of soil organic matter 

content. In 2008, approximately 30.1 million acres (41.3 %) of soybean were planted in a no-till 

system (CTIC 2008). 

Conventional tillage is associated with intensive plowing and less than 15% crop residue at the soil 

surface; reduced tillage is associated with 15 to 30% crop residue; and conservation tillage, including 

no-till practices, is associated with at least 30% crop residue and substantially less soil erosion than 

other tillage practices (CTIC 2010; U.S. EPA 2010a). In 2011, over 65% of U.S. soybean acres used 

some form of conservation tillage (USB 2011c). The decision to plant soybean in a conservation 

tillage or no-till system is made long before planting as it may require special equipment. In 

addition, this decision is usually a long-term commitment, provided the system is successful. 

Slow soybean emergence and growth, plus lower yields, have been some of the concerns associated 

with adoption of conservation tillage systems in soybean, especially no-till. Research in Wisconsin 

and Minnesota shows that soil temperatures can be four to five degrees colder in no-till systems than 

in conventional tillage systems, which can slow emergence, but have little effect on soybean yield 

(Pedersen 2008a). Improved planters for establishment of good soybean populations and planting 

glyphosate-tolerant soybean varieties to effectively control weeds in no-till fields have made no-till a 

more viable production system for soybean. In 1995, before the introduction of glyphosate-tolerant 
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soybean, approximately 27% of the U.S. soybean acres used no-till production. In 2004, nine years 

after the introduction of glyphosate-tolerant soybean, no-till acreage increased to 36% of the total 

soybean acres (Sankula 2006). Using a data set covering 12 states and 11 years, Fernandez-Cornejo, 

et al. (2013) found that herbicide tolerant soybean adoption leads to a significant increase in the 

adoption of conservation tillage. The most recent surveys indicate that 41% of the soybean acres are 

produced using no-till methods (CTIC 2008). Researchers still recommend some spring tillage on 

fine-textured and poorly drained soils for proper seedbed preparation (Pedersen 2008a).

II.B.1.d. Pest Management

The use of pesticides, including fungicides, herbicides, and insecticides, is a key component of an 

integrated pest management (IPM) system in soybean. The various pesticides used in soybean, along 

with other IPM elements, are addressed in the two subsections below.

Disease Management: More than 100 pathogens are known to affect soybean, of which 35 are 

considered to be of economic importance (Bowers and Russin 1999). The estimated yield losses to 

soybean diseases in the U.S. were 12.5, 13.2, and 13.0 million metric tons in 2008, 2009, and 2010, 

respectively (Wrather and Koenning 2011), which equates to 15.5%, 14.4% and 14.4% losses of total 

soybean production, respectively (ASA 2011). Pathogens can affect all parts of the soybean plant, 

resulting in reduced quality and yield. The extent of losses depends upon the pathogen, the state of 

plant development and health when infection occurs, the severity of the disease on individual plants, 

and the number of plants affected (Bowers and Russin 1999). 

According to field surveys conducted in fifteen soybean-producing states during 1996 to 2010,

soybean cyst nematode (Heterodera glycines) caused the greatest soybean yield losses (Wrather and 

Koenning 2011). Phytophthora root and stem rot (Phytophthora sojae), brown spot (Septoria glycines), 

charcoal rot (Macrophomina phaseolina), sclerotinia stem rot (Sclerotinia sclerotiorum), seedling diseases, 

and sudden death syndrome (Fusarium solani f.sp. glycines) followed in economic importance (Wrather 

and Koenning 2011). 

Selecting resistant varieties is the primary tool growers have for disease control (Bowers and Russin 

1999). Resistant varieties may have morphological or physiological characteristics that provide 

immunity, resistance, tolerance or avoidance to certain pathogens. Cultural practices can also play 

an important role in disease management by reducing initial inoculums or reducing the rate of 

disease development (Bowers and Russin 1999). Rotation with non-host crops can help break 

disease cycles, particularly for soybean cyst nematode (Pederson, undated). High-quality seed is 

essential for controlling seedling diseases. Treating soybean seed with a fungicide (e.g., metalaxyl or 

mefenoxam) is effective against damping-off disease (seedling blight) caused by common soil fungi, 

such as Phytophthora and Pythium. Fungicide seed treatments are recommended where there is a 

history of these seedling diseases. 

Management of Insects: Although insects are rated as less problematic than weeds in U.S. 

soybean production, management of insect pests during the growth and development of soybean is 

important for protecting the yield of soybean (Aref and Pike 1998). Understanding the impact of 

insects on soybean growth is essential for proper management (Higley 1994; Steffey, et al. 1994; Way 

1994; Yeargan 1994). It is also important to understand the way that insects injure soybean as well 

as how the soybean plant responds to insect injury. Insect injury can impact yield, plant maturity, or 

seed quality. The ultimate impact of injury is damage, as a measurable reduction in plant growth,

development or reproduction. Insect injury in soybean seldom reaches levels to cause an economic 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 36 of 946

loss in the primary soybean production areas, as indicated by the low percentage (16%) of soybean 

acreage that receives an insecticide treatment (USDA-NASS 2008c).

Characterizing soybean responses to insect injury is essential in establishing economic injury levels 

(Higley 1994; Steffey et al. 1994; Way 1994; Yeargan 1994). Most often, soybean insects pests are 

categorized or defined by the plant parts they injure, namely root-feeding, stem-feeding, leaf-feeding, 

or pod-feeding insects. The root- and stem-feeding insect groups are often the hardest to scout and 

typically are not detected until after they have caused their damage. The leaf-feeding insects 

comprise the biggest group of soybean insect pests, but not necessarily the most economically 

damaging insects. Recent research on defoliation has determined that a major effect of leaf injury is 

to reduce light interception by the soybean canopy which in turn can have a significant effect on 

yield (Higley 1994; Steffey et al. 1994; Way 1994; Yeargan 1994). Soybean, however, has an 

extraordinary capacity to withstand considerable defoliation early in the season without significant 

yield loss. By contrast, defoliation during the flowering and pod filling stages poses a greater threat 

to yield, because the soybean plant has less time to compensate for injury compared to other growth 

stages. Research indicates that the soybean plant can sustain a 35% leaf loss prior to the pre-bloom 

period without lowering yield (NDSU 2002). However, from pod-set to maturity, the plant can 

tolerate only a 20% defoliation level before yield is impacted.

Weeds in Soybeans: Annual weeds are perceived to be the greatest pest problem in soybean 

production, followed by perennial weeds (Aref and Pike 1998). Weed control in soybean is essential 

to optimizing yields because weeds compete with soybean for light, nutrients, and soil moisture. 

Weeds can also harbor insects and diseases, and can interfere with harvest, causing extra wear on 

harvest equipment. 

Foxtail spp. (Setaria spp.), pigweed (Amaranthus spp.), velvetleaf (Abutilon theophrasti), lambsquarters 

(Chenopodium album), and cocklebur (Xanthium strumarium) are common weeds in Midwest corn and 

soybean fields. Certain growers in Indiana have reported giant ragweed (Ambrosia artemisiifolia), 

lambsquarters, Canada thistle (Cirsium arvense), cocklebur, and velvetleaf to be difficult-to-control

weeds in corn and soybean (Nice and Johnson 2005). Giant and/or common ragweed are also 

common and problematic in Minnesota, Missouri, Arkansas, Wisconsin and Illinois (Anderson 2012; 

Boerboom and Owen 2006; Iowa State University 2003). In a 2005-2006 survey of 1,200 growers of 

glyphosate-tolerant crops (soybean, corn and cotton) in six Midwestern and southern states, growers 

in Illinois and Iowa, the two leading soybean-producing states, most frequently named common 

waterhemp (Amaranthus tuberculatus) as most difficult to control (Kruger, et al. 2009). Waterhemp is 

also reported to be a problematic in Minnesota, Indiana, Nebraska, Wisconsin and Missouri 

(Anderson 2012; Boerboom and Owen 2006; Iowa State University 2003; Kruger et al. 2009; 

Legleiter, et al. 2009). Horseweed (Conyza canadensis, also called marestail) has been reported to be

problematic in Ohio, Arkansas, Tennessee, Kansas, Wisconsin and Illinois (Boerboom and Owen 

2006; Mueller, et al. 2005; Peterson and Shoup 2012). 

Tables II.B-3 through II.B-5 summarize the most common weeds for the three primary major 

soybean growing regions (Midwest, Southeast and Eastern Coastal). The Plains region is not 

discussed due to the low levels of soybean cultivation, < 1% U.S. soybean acres.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 37 of 946

Table II.B-3. Common Weeds in Soybean Production: Midwest Region

Foxtail spp. (12)1 Ragweed, giant (3) Dandelion (1)

Pigweed spp. (11) Shattercane (3) Johnson grass (1)

Velvetleaf (11) Quackgrass (3) Milkweed, honeyvine (1)

Lambsquarters (10) Buckwheat, wild (2) Nightshade, hairy (1)

Cocklebur (9) Crabgrass spp. (2) Oats, wild (1)

Ragweed, common (7) Kochia (2) Pokeweed, common (1)

Smartweed spp. (6) Mustard, wild (2) Prickly sida (1)

Morningglory spp. (5) Nightshade, Eastern black (2) Proso millet, wild (1)

Sunflower, spp. (5) Palmer pigweed (2) Sandbur, field (1)

Waterhemp spp. (5) Canada thistle (1) Venice mallow (1)

Horseweed (marestail) (3) Chickweed (1) Volunteer cereal (1)

Panicum, fall (3) Cupgrass, woolly (1) Volunteer corn (1)

1 Number provided in parenthesis is the number of states out of the thirteen total states in the Midwest

region reporting each weed as a common weed.

Sources: 

IL: University of Illinois (2002) and Aaron Hager, Extension Weed Specialist, University of Illinois -

Personal Communication (2006).

IN: 2003-2005 Statewide Purdue Horseweed Weed Survey, Special database query and personal 

communication (2006), Bill Johnson, Extension Weed Specialist, Purdue University.

IA, MN, OH, WI: (WSSA 1992). 

KS: Dallas Petersen, Extension Weed Specialist, Kansas State - Personal communication (2006).

KY, MO: (Webster, et al. 2005).

MI: (Davis, et al. 2005). 

NE: Alex Martin, Extension Weed Specialist, University of Nebraska – Personal communication (2006).

ND: (Zollinger and Lym 2000).

SD: Michael Moechnig, Extension Weed Specialist, South Dakota State University – Personal 

communication (2006).

Table II.B-4. Common Weeds in Soybean Production: Southeast Region

Morningglory spp. (8)1 Goosegrass (3) Cutleaf evening-primrose (1)

Crabgrass spp. (6) Johnsongrass (3) Groundcherry (1)

Prickly sida (6) Ragweed, common (3) Henbit (1)

Nutsedge spp. (6) Cocklebur (2) Lambsquarters (1)

Sicklepod (5) Florida beggarweed (2) Ragweed, giant (1)

Signalgrass, broadleaf (5) Hemp sesbania (2) Smartweed (1)

Palmer pigweed (4) Horseweed (marestail) (2) Spurge, nodding/hyssop (1)

Pigweed spp. (4) Texas millet (2) Spurge, Prostrate (1)

Barnyard grass (3) Browntop millet (1) Tropic croton (1)

Florida pusely (3) Copperleaf, hophorn (1)

1 Number provided in parenthesis is the number of states out of the eight total states in the Southeast 

region reporting each weed as a common weed. 

Sources:

AL, AR, GA, LA, NC, SC: (Webster, et al. 2009). 

MS, TN: (Webster et al. 2005).
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Table II.B-5. Common Weeds in Soybean Production: Eastern Coastal Region

Foxtail spp. (6)1 Morningglory spp. (4) Dandelion (1)

Ragweed, common (6) Panicum, fall (4) Goosegrass (1)

Velvetleaf (6) Crabgrass spp. (3) Johnson grass (1)

Lambsquarters (5) Nutsedge spp. (3) Nightshade, Eastern black (1)

Pigweed spp. (5) Quackgrass (2) Prickly sida (1)

Cocklebur (4) Canada thistle (1) Shattercane (1)

Jimson weed (4) Burcucumber (1) Smartweed spp. (1)

1 Number provided in parenthesis is the number of states out of the six total states in the Eastern 

Coastal region reporting each weed as a common weed. Data were not available for DE in soybean. 

Sources:

DE, MD, NJ, PA: (WSSA 1992). 

NY: Russell Hahn, Extension Weed Specialist, Cornell University – Personal Communication (2006). 

VA: (Webster et al. 2009).

Benefits of Herbicide Use in Agriculture: A study by CropLife America demonstrated that in 

2005 the use of herbicides saved U.S. farmers 337 million gallons of fuel, produced $16 billion in 

crop yield increases, and cut weed control costs by $10 billion as compared to production without 

the use of herbicides (Gianessi and Reigner 2006). Additionally, without herbicides growers would 

have to abandon no-till or other conservation tillage production practices, which reduce soil erosion. 

If U.S. growers stopped using herbicides and resumed tillage on the number of acres not tilled in 

2005, an additional 356 billion pounds of sediments would be deposited in streams and rivers, 

resulting in an estimated $1.4 billion in downstream damage (Gianessi and Reigner 2006).

Weed Management in Soybean: The factors that affect a potential yield loss in soybean from 

weed competition are the weed species, weed density, and the duration of the competition. When 

weeds are left to compete with soybean for the entire growing season, yield losses can exceed 75% 

(Dalley, et al. 2001). Generally, the competition between crops and weeds increases with increasing 

weed density. The time period that weeds compete with the soybean crop influences the level of 

yield loss. In general, the later the weeds emerge, the less impact the weeds will have on yield. 

Soybean plants withstand early-season weed competition longer than corn, and the canopy generally 

closes earlier in soybean than corn (i.e., plants in adjacent rows grow to a sufficient size such that 

their foliage touches between the rows blocking the sunlight from reaching the ground and prevents 

weed seeds from germinating). In addition, canopy closure is much sooner when soybean is planted 

in narrow rows. 

The most effective weed management programs in soybean use a combination of cultural, 

mechanical, and/or herbicide control practices, hereafter called diversified weed management 

practices, instead of relying on one particular method of weed control (Beckie, et al. 2011; University 

of California 2009; Vargas, et al. 1996). Herbicide application practices that are compatible with 

diversified weed management practices include the use of several herbicides with different modes of 

action, either within or across seasons, applying herbicides at the labeled rate at the correct timing, 

and proper application of the herbicide. Cultural and mechanical practices can also be important 

components of an effective diversified weed management program (Ashigh, et al. 2012). Cultural 

practices such as crop rotation, narrow row spacing and planting date are a few of the crop 

management practices that are implemented to provide the crop with a competitive edge over 

weeds. Mechanical methods of weed control, including tillage, have been used for centuries to 

control weeds in crop production. Spring or fall preplant tillage and in-crop shallow cultivation can 
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effectively reduce the competitive ability of weeds by burying the plants, disturbing or weakening 

their root systems, or causing sufficient physical injury to kill the plants. A consequence of in-crop 

cultivation for weed control is that it can injure crop roots and cause moisture loss. The planting of 

winter cover crops is another cultural practice that can also be utilized. The planting of cover crops, 

such as grasses, legumes or small grains, can protect and improve soil quality, help reduce erosion, 

and can serve as surface mulch in no-till cropping practices (Mannering, et al. 2007). Although in 

recent years there has been a resurgence in interest by crop experts and academics in the use of 

cover crops, the planting of a cover crop incurs additional costs to the grower and therefore is not

currently a major weed management practice in major soybean growing areas (Singer 2006). 

The use of herbicides has become an important part of managing weeds in soybean. Approximately 

98 percent of the soybean acreage received an herbicide application in 2012 (USDA-NASS 2012d). 

The availability of herbicide-tolerant soybean products is an important aspect of weed management 

in U.S. soybean production. Herbicide-tolerant soybean was introduced to provide growers with 

additional options by improving crop safety (no herbicide damage to the crop) and improving weed 

control. In 2013, 93% of the U.S. soybean crop was herbicide-tolerant (USDA-ERS 2013); almost 

all is glyphosate-tolerant. As a result and as shown by the 2012 use data shown in Appendix A, 

Table A-8, glyphosate is the most widely used herbicide, being applied on 98 percent of the soybean 

acreage in 2012, including for preplant burndown and postemergence in crop applications (USDANASS 2012d). In 2012, dicamba-treated acres in soybean accounted for only 87 thousand acres, or 

0.07% of the total preemergent treated acres (USDA-NASS 2012d). This is primarily because 

dicamba is phytotoxic to current soybean varieties and is therefore currently only labeled for 

application at timings that avoid contact with the growing plant, such as preplant treatments prior to 

planting, depending on rate and rainfall.

Over 35 different herbicide active ingredients are registered and available for use by soybean 

growers to control weeds. The ten most widely used alternative herbicides in soybean are listed in 

Table II.B-6. Alternative soybean herbicide use has almost doubled between 2009 and 2012. 

Integration of DT soybean into the glyphosate-tolerant soybean system and the subsequent use of 

dicamba will result in the displacement of some currently used, or foreseeable future use, 

non-glyphosate herbicides. Some non-glyphosate alternative herbicides have less benign human 

health and environmental characteristics as compared to dicamba, and reduced agronomic flexibility 

due to soybean planting restrictions, rotational crop planting restrictions, the need for adequate soil 

moisture for activation, or the need to apply prior to planting to minimize crop injury.

33

 The 

properties of these alternative herbicides are summarized in Appendices A and C to provide a 

baseline for comparison to dicamba use on DT soybean.

Herbicide weed control programs in conventional soybean consist of preemergence herbicides used 

alone or in mixtures. Mixtures of two preemergence herbicides are used to broaden the spectrum of 

control to both grasses and broadleaf weed species. Preemergence herbicides are followed by 

 

33 In order to approve a new use of a herbicide EPA must conclude that the herbicide, when used according to the label, does not 

pose an unreasonable adverse effect to humans or the environment, and, in order to establish a tolerance for the use of a 

herbicide on a food or feed crop, find there is a reasonable certainty of no harm to human health from non-occupational (food, 

water and residential/recreational) exposures to the herbicide. Therefore, all alternative herbicides used in soybean production 

can be used safely, and do not pose an unreasonable risk to humans or the environment. 
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postemergence applications to control weeds that emerge later in the crop. Total postemergence 

weed control programs were seldom used in conventional soybean prior to 1995 when 

glyphosate-tolerant soybean was first introduced. Prior to glyphosate-tolerant soybean, soybean 

planted in a no-till system would receive a preplant burndown herbicide application for broadspectrum control of existing weeds at time of planting, followed by different soil residual herbicides 

at planting and possibly still other herbicides applied postemergence to the crop and the weeds. In 

conventional soybeans, the typical herbicide program consisted of multiple soil residual herbicides 

applied preemergence to the crop and weeds and, possibly, other herbicides applied postemergence 

to the crop and weeds. Therefore, multiple herbicides and/or multiple applications were generally

used in conventional and no-till non-glyphosate-tolerant soybean. The average number of herbicide 

applications per acre in soybean rose from 1.5 in 1990 to 1.7 applications in 1995, reflecting the use 

of at-plant and postemergence applications or two postemergence applications (Gianessi, et al. 

2002).

Table II.B-6. Ten Most Widely Used Alternative Herbicides in U.S. Soybean Production in 

2012

Herbicide Treated Acres 

(millions)1

Pounds Applied

(millions)1

2,4-D (acid, salts, and esters, 

combined)

11.58 6.02

Flumioxazin 8.49 1.56

Imazethapyr 3.86 1.35

cloransulam-methyl 3.09 0.60

chlorimuron-ethyl 8.49 0.52

Fomesafen 6.18 0.22

Clethodim 6.95 0.19

pendimethalin 1.54 0.08

Tribenuron 0.77 0.04

flumiclorac-pentyl 0.77 0.01

1 (USDA-NASS 2012d)

Selective herbicides are designed to kill specific types of plants, usually grasses or broadleaf weeds, 

and have proven effective to reduce in-crop tillage or cultivation to control weeds in soybean 

production. The development of selective herbicides has progressed since the introduction of the 

first herbicide (2,4-D) for weed control in corn in early 1940s. Although the primary purpose of 

tillage is for seedbed preparation, tillage still is used to supplement weed control with selective 

herbicides in soybean production. Refer to Appendix A for details on alternative herbicides used in 

soybean production.

Dicamba Herbicide Use: Dicamba is a broadleaf selective herbicide that was approved by the 

U.S. Environmental Protection Agency (EPA) for agricultural application uses in 1967 (U.S. EPA 

2009d). Dicamba is formulated as a standalone herbicide product and marketed by several 

companies under various trade names such as Banvel®, Clarity®, Diablo®, Rifle®, Sterling®, and 

Vision®. These dicamba products can also be tank-mixed with one or more active ingredients 

depending on the crop to be treated. For example, Clarity® can be tank mixed with over 75 

herbicide products in labeled crops. Additionally, dicamba is currently formulated as a premix 

product with one or more other herbicide active ingredients, including glyphosate, 2,4-D, 
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diflufenzopyr, atrazine, nicosulfuron, metsulfuron, primsulfuron, triazulfuron, rimsulfuron, and 

halosulfuron. 

Dicamba is currently labeled for weed control in corn, soybean, cotton, sorghum, wheat, barley, 

oats, millet, pasture, rangeland, asparagus, sugarcane, turf, grass grown for seed, conservation reserve 

programs, and fallow croplands. Dicamba-treated acreage has ranged from 17.4 to 36.3 million 

acres between 1990 and 2011. Usage of dicamba peaked during the period of 1994 through 1997, 

where 1994 was the peak year when 36 million crop acres were treated with 9.4 million pounds of 

dicamba. Since then, the use of dicamba has steadily declined to 17.4 million treated acres with 2.7 

million pounds applied in 2006. The reduction in dicamba use has been attributed to the 

competitive market introductions of sulfonylurea herbicides (chlorsulfuron, metsulfuron-methyl, and 

thifensulfuron-methyl) in wheat, new broadleaf herbicide active ingredients in corn, and 

introduction of glyphosate-tolerant corn. More recently, however, dicamba-treated acres have been 

on the rise and have increased by as much as 7.9 million acres between 2006 to 2011; see Appendix 

A, Table A-1 for additional details. Most of this increase has occurred in fallow, pastureland, 

sorghum, and cotton (preplant) (Monsanto 2012). 

Based on farm survey data generated in 2011 by a private market research company, dicamba 

application rates across agricultural row crops ranged from 0.07 to 0.27 pounds per acre with the

average number of applications ranging from 1 to 1.4 applications per cropping season (Monsanto 

2012). Dicamba rates (pounds per acre) are lowest in spring wheat where more than one application 

is typically made per cropping season. 

Dicamba is currently labeled for use in conventional or glyphosate-tolerant soybean, although 

dicamba use is extremely limited because applications are restricted to very early preplant and/or 

preharvest applications due to soybean (crop) injury concerns. The dicamba-treated acreage in 2008 

soybean production was approximately 872,000 acres, representing 1.2 % of the total soybean 

acreage (Monsanto 2009); see Appendix A, Table A-2 for additional details.

Dicamba belongs to the auxin class of herbicides, which is the oldest class of known synthetic 

herbicides. This class includes 2,4-D, 2,4-DB, mecoprop, MCPA, clopyralid, and several other active 

ingredients, and is WSSA Herbicide Group Number 4 (HRAC 2009).

34

 On the basis of their 

structural and chemical properties, auxinic herbicides have been classified into several sub-groups, 

viz., phenoxyalkanoic acids (e.g., 2,4-D, MCPA), benzoic acids (e.g., dicamba, chloramben), 

pyridines (e.g., picloram, clopyralid), and quinolinecarboxylic acids (e.g., quinclorac, quinmerac). 

Generally, auxinic herbicides are effective against broadleaf (dicotyledonous) plant species, allowing 

them to often be used in production of narrow leaf (monocotyledonous) crops. Refer to Appendix 

A for details on dicamba herbicide.

Herbicide Resistance: Herbicide resistance is “the inherited ability of a plant to survive and 

reproduce following exposure to a dose of herbicide normally lethal to the wild type” (WSSA 1998). 

In the mid-1950s, Harper (1957) theorized that annual, repeated use of a herbicide could potentially 

lead to shifts in weed species composition within a crop-weed community if other weed 

 

34 There are several systems of herbicide mode-of action classification. Among the most widely used are those of the Herbicide 

Resistance Action Committee (HRAC) and the Weed Science Society of America. 
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management methods are not utilized. Similarly, Bandeen et al. (1982) suggested that a normal 

variability in response to herbicides exists among plant species and tolerance can increase with 

repeated use of a herbicide in the absence of other weed management methods. To simplify, 

herbicide resistance in weeds is a result of natural selection. Plants of a given species are not all 

identical, but are made up of “biotypes” with various genetic traits. The repeated use of a herbicide 

may potentially lead to the selection of weed biotypes resistant to that herbicide, particularly when 

the herbicide is not used as part of a diversified weed management program. Within a weed species, 

individuals may possess an inherent ability to withstand the effects of a particular herbicide. 

Repeated use of that herbicide in the absence of other weed control herbicides or practices has the 

potential to expose the weed population to a “selection pressure,” which may potentially lead to an 

increase in the number of surviving resistant individuals in the population (HRAC 2011). With 

repeated application of the same herbicide over time and no other appropriate herbicide or weed 

management practices, the resistant biotypes have the potential to become the dominant biotype in 

that weed community. As of April 2013, 400 herbicide-resistant weed biotypes have been reported 

to be resistant to 21 different herbicide modes-of-action worldwide (Heap 2013b). Glyphosateresistant weeds account for approximately 6% of the herbicide-resistant biotypes while weeds 

resistant to herbicides that inhibit acetolactate synthase (ALS) account for 32% of the herbicideresistant biotypes. Dicamba-resistant and glufosinate-resistant weeds account for <1% and 0.5% of 

resistant biotypes respectively (Heap 2012c; d; 2013b). See Appendix B of this environmental report 

for details of effects of weed resistance. 

For as long as herbicide resistance has been a known phenomenon, public-sector weed scientists, 

private-sector weed scientists, and growers have been identifying methods to address the problem. 

For instance, when a farmer uses multiple weed control tools, resistant biotypes generally will not 

become the dominant biotype within a population (Gunsolus 2008). By contrast, there is a great 

potential for weed resistance in areas where there is a sole reliance on a single herbicide used 

repeatedly over multiple crop generations for the management of a specific weed spectrum, and 

where appropriate weed management practices are not utilized.

On agricultural land which contains a weed biotype that is resistant to a particular herbicide, the 

grower must use alternate methods of weed control. Management practices that can be used to 

mitigate the potential for development of resistance include herbicide mixtures, herbicide rotation, 

and crop rotation. Since many soybean farmers practice conservation tillage and some may choose 

to plant soybeans repeatedly on the same land, the use of multiple herbicide modes of action with 

overlapping effectiveness on the targeted weed spectrum will be an important method 

recommended, and there are an increasing number of farmers who are following such

recommendations. The WSSA reports: “Weed scientists know that the best defense against weed 

resistance is to proactively use a combination of agronomic practices, including the judicious use of 

herbicides with alternative modes-of-action either concurrently or sequentially” (WSSA 2010). 

Studies have demonstrated that using the same combination of herbicides with multiple modes of 

action and overlapping effectiveness over multiple seasons is an effective way to proactively manage 

resistance (Beckie and Reboud 2009; Neve, et al. 2011).

Due to the broad spectrum activity of glyphosate, it has been possible for growers to rely on 

glyphosate for weed management without utilizing other weed management practices such as crop 

rotation, cultivation, or use of multiple herbicide modes of action; these practices have resulted in 

the selection of certain glyphosate-resistant weed biotypes in certain areas of the U.S. 
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As with other herbicide-resistant weeds that have developed, the emergence of herbicide-resistant

weeds over the past decade, including glyphosate-resistant weed biotypes in certain areas of the U.S.

has meant that growers have needed to adapt and implement various weed management strategies. 

Glyphosate-resistant weed biotypes that can be found in soybean fields in certain areas of the U.S.,

include Palmer pigweed (Amaranthus palmeri), spiny pigweed (Amaranthus spinosus), tall waterhemp 

(Amaranthus tuberculatus), common ragweed (Ambrosia artemisiifolia), giant ragweed (Ambrosia trifida), 

horseweed (Conyza canadensis), kochia (Kochia scoparia), goosegrass (Eleusine indica), Italian ryegrass 

(Lolium multifloru), and Johnsongrass (Sorghum halepe) (Heap, 2013). 

Tables II.B-9 and II.B-10 summarize known resistance among the major weed species present in 

soybean within each of the key soybean herbicide groups and herbicide classes active on broadleaf 

weeds (Heap 2013b). Resistance to the ALS group of herbicides is present in most of the major 

broadleaf weed species commonly found in soybeans. For common ragweed and waterhemp there 

is known resistance to at least one member for several of the major soybean herbicide chemistry 

classes. While many effective options exist for managing common ragweed, waterhemp, Palmer 

pigweed and other key broadleaf weeds, the availability of additional herbicide modes-of-action will 

help mitigate the potential for development of future resistance in soybeans and manage existing 

herbicide-resistant weed populations. There has also been an increase in the detection of weed 

populations with multiple resistance (i.e., resistance to multiple herbicide modes-of-action) in certain

weed species, for example, Amaranthus spp. (Tranel, et al. 2010). The emergence of these resistant 

biotypes demonstrates the continued need to utilize diversified weed management practices, 

including the need for additional herbicide modes-of-action in major crops such as soybeans. 

The relative occurrence of herbicide-resistant weeds varies between the different sub-groups of 

auxinic (phenoxy in Tables II.B.9 and II.B-10) herbicides. Considering that auxin herbicides have 

been widely used in agriculture for more than 60 years, weed resistance to this class is relatively low 

(29 species, to date, worldwide) and its development has been slow, especially when compared to the 

speed of appearance of resistance to ALS inhibitors (107 species) or triazine-resistant populations 

(68 species) (Heap 2012d). The relatively low incidence of auxinic herbicide resistance is believed to 

be attributable to the fact that there are multiple target sites for these herbicides (Gressel and Segel 

1982; Morrison and Devine 1993).

Monsanto scientists and academics recommend the use of multiple herbicide modes-of-action for 

glyphosate-tolerant soybean regardless of whether glyphosate-resistant or hard –to-control broadleaf 

weeds are present. Monsanto specifically recommends the use of a soil residual as part of the weed 

management system. Growers may also choose to switch to other weed management systems in 

their soybean fields. APHIS has approved other herbicide tolerant soybean including 

phosphinothricin-tolerant, ALS-tolerant and HPPD tolerant soybean events (Table II.B-11). For 

growers who choose to use glyphosate-tolerant soybean, Monsanto and university extension agents 

provide recommended control options for glyphosate-resistant weeds. These options include the 

use of residual and postemergent herbicides such as synthetic auxins (2,4-D), ACCase inhibitors 

(clethodim, sethoxydim), PPO inhibitors (lactofen, fomesafen), and ALS inhibitors (cloransulam).35 

 

35 Monsanto Technology Use Guide; www.weedresistancemanagement.com.
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These herbicides alone or combinations of these herbicides as well as traditional tillage methods are 

and will continue to be used to control glyphosate-resistant or hard-to-control broadleaf weeds.

While the utilization of additional weed management practices has occurred particularly in 

glyphosate-tolerant corn and cotton, such practices are also occurring in glyphosate-tolerant 

soybeans. In a 2005 survey of growers in six states, 15 to 21% of growers applied non-glyphosate 

herbicides in addition to glyphosate for weed control in glyphosate-tolerant soybean (Givens, et al. 

2009a). These non-glyphosate herbicides were applied prior to planting, at planting and/or 

postemergence in soybean. In another grower survey conducted at the end of the 2009 growing 

season, in certain areas of the U.S., the percent of growers applying non-glyphosate herbicides rose 

to 33% for those growing continuous glyphosate-tolerant soybean, and to 33% and 52% for growers 

growing glyphosate-tolerant soybean in rotation with only glyphosate-tolerant corn and only cotton, 

respectively (personal communication from Dr. David Shaw, December 2011). More recently, a 

survey indicated that approximately 30 and 43% of glyphosate-tolerant soybean planted acres are 

using non-glyphosate postemergence and soil applied residual herbicides, respectively, in addition to 

glyphosate in 2011 (See Appendix A, Table A-12 and A-13) (Monsanto 2009). These data indicate a 

trend towards increased diversification of weed management practices in glyphosate-tolerant crops. 

Further evidence of increased adoption of diversified weed management practices, including 

incorporation of multiple herbicide modes-of-action, across glyphosate-tolerant corn, cotton and 

soybean is presented by Prince et. al. (2011b). Furthermore, researchers report that approximately 

40 to 50% of the growers utilizing glyphosate-tolerant crops in major soy- and cotton-growing areas

indicate that rotating herbicides or tank mixing glyphosate with other herbicides is an effective 

management practice to minimize the development of glyphosate resistance (Beckie 2006; Beckie 

and Reboud 2009; Diggle, et al. 2003; Powles, et al. 1996). Indeed, as described in detail below, a 

prominent strategy to mitigate the potential for development of herbicide-resistant weeds is to 

increase the diversity of weed management options in agriculture, including use of herbicides with 

different modes-of-action in a grower’s weed management program (Duke and Powles 2009). Refer

to Appendix B for details on herbicide resistance.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 45 of 946

Table II.B-9. Known Weed Resistance in the Southern U.S.1

Most 

Common 

Broadleaf 

Weeds 

(# states 

where 

listed as a 

top 

weed)

Resistance 

Group 2

ALS

(Group 2)

PPO 

(Group 14)

PS II 

(Group 5)

Glycine 

(Group 9)

Phenoxy 

(Group 4)

Chemistry 

Class 2

Sulfonyl 

Urea

Imidazolinones Triazoles Diphenyl 

ether

N-phenyl 

thalimide

Triazinones - Phenoxy Benzoic 

acid

Example chlorimuron imazethapyr chloransulam lactofen

fomesafen

flumioxazin metribuzin glyphosate 2,4 D dicamba

Morning glory (5)

Sida (prickly sida (5) X

Sicklepod (4)

Hemp sesbania (3)

Pigweed spp. 3(3) X X X X X X X

Palmer pigweed (2) X X X X

Cocklebur (1) X X X

Horseweed (marestail) 

(1)

X X X

1 Source: www.weedscience.org

2 Cross resistance is possible within a resistance group and/or chemistry class

3 Includes redroot pigweed, common waterhemp, spiny amaranth and smooth pigweed
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Table II.B-10. Known Weed Resistance in the Midwest U.S. 1

Most 

Common 

Broadleaf 

Weeds 

(# states 

where 

listed as a 

top 

weed)

Resistance 

Group 2

ALS

(Group 2)

PPO 

(Group 14)

PS II 

(Group 5)

Glycine (Group 9) Phenoxy 

(Group 

4)

Chemistry 

Class 2

Sulfonyl 

Urea

Imidazolinones Triazoles Diphenyl 

ether

N-phenyl 

thalimide

Triazinones - Phenoxy Benzoic 

acid

Example chlorimuron imazethapyr chloransulam lactofen

fomesafen

flumioxazin metribuzin glyphosate 2,4 D dicamba

Pigweed spp. 3 (12) X X X X X

Velvetleaf (11)

Lambsquarters (10) X X X

Cocklebur (9) X X X

Common ragweed (7) X X X X X X

Smartweed spp. (6)

Morning glory (5)

Waterhemp (5) X X X X X X

Horesweed (marestail) 

(3)

X X X

Giant ragweed (3) X X X X

Kochia (2) X X X X

1 Source: www.weedscience.org

2 Cross resistance is possible within a resistance group and/or chemistry class

3 Includes redroot pigweed and smooth pigweed
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Table II.B-11. Deregulated Biotechnology-derived Soybean Products1

Phenotype Event Institution Date Deregulated

Herbicide-tolerant

(Glyphosate/Isoxaflutole)

FG72 Bayer

Crop Sciences

August, 2013

Omega 3 Fatty Acid MON 87769 Monsanto July, 2013

High Oleic Acid, Low 

Saturated Fat

MON 87705 Monsanto December, 2011

Lepidopteran Resistant MON 87701 Monsanto June, 2011 

High Oleic Acid DP-3Ø5423-1 Pioneer June, 2010

Glyphosate- and ALStolerantDP-356043-5 Pioneer July, 2008

Glyphosate-tolerant MON 89788 Monsanto February, 2007

Phosphinothricin-tolerant GU262 AgrEvo October, 1998

Phosphinothricin-tolerant A5547-127 AgrEvo May, 1998

Altered Oil Profile G94-1, G94-19, G-168 DuPont May, 1997

Phosphinothricin-tolerant W62, W98, A2704-12, 

A2704-21, A5547-35

AgrEvo August, 1996

Glyphosate-tolerant 40-3-2 Monsanto May, 1994

1

(USDA-APHIS 2013b)

II.B.1.e. Organic Production Practices 

National Organic Program and Organic Soybean Farming: In the U.S., only products 

produced using specific methods and certified under the USDA’s Agricultural Marketing Service 

(AMS) National Organic Program (NOP) definition of organic farming can be marketed and labeled 

as “organic” (USDA-AMS 2010). Organic certification is a process-based certification, not a 

certification of the end product; the certification process specifies and audits the methods and 

procedures by which the product is produced.

In accordance with NOP, an accredited organic certifying agent conducts an annual review of the 

certified operation’s organic system plan and makes on-site inspections of the certified operation 

and its records. Organic growers must maintain records to show that production and handling 

procedures comply with USDA organic standards.

The NOP regulations preclude the use of excluded methods. The NOP provides the following 

guidance under 7 CFR § 205.105:

“...to be sold or labeled as ‘100 percent organic’, ‘organic’ or ‘made 

with organic (specified ingredients or group(s)),’ the product must be 

produced and handled without the use of:
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 48 of 946

(a) Synthetic substances and ingredients,...

(e) Excluded methods,...”

Synthetic Substances are defined in 7 CFR § 205.2 as:

“A substance that is formulated or manufactured by a chemical 

process or by a process that chemically changes a substance extracted 

from naturally occurring plant, animal, or mineral sources, except that 

such term shall not apply to substances created by naturally occurring 

biological processes.” This includes synthetic herbicides, insecticides, 

and fertilizers.

Finally, excluded methods are defined as:

“A variety of methods used to genetically modify organisms or 

influence their growth and development by means that are not 

possible under natural conditions or processes and are not considered 

compatible with organic production...”

Organic farming operations, as described by the NOP, are required to have distinct, defined 

boundaries and buffer zones to prevent unintended contact with prohibited substances and excluded 

methods from adjoining land that is not under organic management. Organic production operations 

must also develop and maintain an organic production system plan approved by their accredited 

certifying agent. This plan enables the production operation to achieve and document compliance 

with the National Organic Standards, including the avoidance of use of prohibited substances and 

excluded methods (USDA-AMS 2010).

Most EPA-registered synthetic pesticides are prohibited in organic production; however, there is the 

potential for inadvertent or indirect contact from neighboring conventional farms or shared 

handling facilities. As long as the operator has not directly applied prohibited pesticides and has 

documented efforts to minimize exposure to them, the USDA organic regulations allow for residues 

of prohibited pesticides at or below 5 percent of the EPA tolerance. (USDA-AMS 2012b). 

Although the National Organic Standards preclude the use of excluded methods, they do not require 

testing of inputs or products for the presence of excluded methods. The presence of a detectable 

residue of a product of excluded methods alone does not necessarily constitute a violation of the 

National Organic Standards (USDA-AMS 2011). The current NOP regulations do not specify an 

acceptable threshold level for the adventitious presence of GE materials in an organic-labeled 

product. The unintentional presence of the products of excluded methods will not affect the status 

of an organic product or operation when the operation has not used excluded methods and has 

taken reasonable steps to avoid contact with the products of excluded methods as detailed in their 

approved organic system plan (USDA-AMS 2011).

Organic soybean producers use production practices designed to prevent commingling of their 

value-added crop with neighboring crops treated with herbicides and other pesticides or that may be 

using plant varieties produced by excluded methods. In addition, steps are taken to avoid spray drift 

from neighboring fields. These well-established practices include isolation zones, use of buffer rows 

surrounding the organic crop, adjusted planting dates, and varietal selection (Kuepper 2006). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 49 of 946

The efficacy of management practices utilized to avoid pollen movement from a GE crop to organic 

soybean production operations is facilitated by the nature of soybean pollination. Soybean is a 

highly self-pollinated species and exhibits a very low level of outcrossing (see Section II.D.1.c) 

Outcrossing most commonly results from cross-pollination. Since soybean is highly self-pollinating, 

organic or conventional soybean producers can and have effectively implemented practices (e.g., 

isolation during the growing season, equipment cleaning during harvest, and post-harvest separation 

of harvested seed) that allow them to reasonably avoid biotechnology-derived soybean and maintain 

organic or conventional production status (Brookes and Barfoot 2004).

U.S. Organic Soybean Production: Organic soybean was produced on 96,080 acres in 2011 and 

yielded 2.9 million bushels, equal to approximately 0.09% of U.S. soybean production (USDA-NASS 

2013b). The average yield was 30 bushels per acre. Major production states are Iowa, Minnesota, 

Michigan, New York, Illinois, Nebraska, and Wisconsin (USDA-NASS 2012d). Based upon recent 

trend information, the presence of GE soybean varieties on the market has not affected the ability 

of organic production systems to maintain their market share. 

Organic soybean production practices include crop rotation, use of cover crops, green and animal 

manures, application of rock minerals such as lime, other soil additives, mechanical weed control, 

biological control of pests, and disease control primarily through management practices (CAST 

2009; Kuepper 2003; USDA-AMS 2011).

II.B.1.f. Other Specialty Market Production

Other specialty soybean include those used for specific food products (e.g., fermented soy food, 

tofu, soymilk, sprouts, soy nuts [roasted seed] and edamame [green seed]), those grown for special 

oil or seed traits (e.g., reduced linolenic acid, high oleic acid, and high protein) and non-GE soybean 

(Lee and Herbek 2004; University of Kentucky 2009). These specialty soybeans are typically grown 

under contract for a specific market.

Specialty soybean are grown on fewer acres than commercial or commodity soybean and are grown, 

harvested and handled separately from commodity soybean. Specialty soybean must be segregated 

from other soybean throughout the production, storage and shipping process to preserve its identity.

II.B.1.g. Seed Production Services

Seed quality (including genetic purity, vigor, and presence of weed seed, seed-borne diseases, and 

inert materials such as dirt) is a major factor in crop yields. If natural variability in seed production 

is not carefully controlled, the value of a new variety or cultivar may be lost (Hartmann, et al. 1975). 

Genetic purity in commercial seed production is generally regulated through a system of seed 

certification which is intended to ensure that the desired traits in the seed are maintained throughout 

all stages in cultivation (Hartmann et al. 1975).

States have developed seed laws and certification agencies to ensure that purchasers who received 

certified seed can be assured that the seed meets established seed quality standards (Bradford 2006). 

The U.S. Federal Seed Act of 1939 recognizes seed certification and official certifying agencies. 

Implementing regulations further recognize land history, field isolation, and varietal purity standards 

for Foundation, Registered, and Certified seed.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 50 of 946

In a seed certification program, classes of seed are identified to designate the seed generation from 

the original breeder source (Hartmann et al. 1975). Foundation seed, Registered seed, and Certified 

seed production is controlled by public or private seed certification programs (AOSCA 2009a). The 

original seed breeder seed stock is controlled by the developer of the variety (Adam 2005; Hartmann 

et al. 1975). The breeder stock is used to produce Foundation seed stock (Adam 2005). The 

institution associated with the breeder controls the production of Foundation seed stock. 

Foundation seed stock, in turn, is used to produce Registered seed for distribution to licensees, such 

as seed companies (Adam 2005). Registered seed is used by seed companies to produce large 

quantities of Certified seed (Adam 2005; Hartmann et al. 1975). The Certified (or Select) seed is 

then sold to growers through commercial channels (Adam 2005; Hartmann et al. 1975). 

Seed certification cultivation practices commonly include recommendations for minimum isolation 

distances between various seed lines and planting border or barrier rows to prevent pollen 

movement (Hartmann et al. 1975; Wozniak and Martinez 2011). The isolation distance for 

Foundation, Registered, and Certified seeds, as dictated by the USDA Agricultural Marketing 

Service’s (AMS) Federal Seed Act, is 1,320, 1,320, and 660 feet, respectively (7 CFR Part 201.76). 

During the growing season, seed certification agencies will monitor the fields for off-types, other 

crops, weeds, and disease (Wozniak and Martinez 2011). These certifying agencies also establish 

seed handling standards to reduce the likelihood of seed source mixing during production stages, 

including planting, harvesting, transporting, storage, cleaning, and ginning (Wozniak and Martinez 

2011). Further discussion of cross-pollination, gene transfer, and weediness is presented in Section 

II.D.1.c. 

II.B.2. Agricultural Production of Cotton

II.B.2.a. Crop Use and Biology

Cotton: Cotton belongs to the genus Gossypium, which currently encompasses approximately 50 

species widely cultivated in tropical and subtropical regions around the world (OECD 2008; 

Percival, et al. 1999). There are four cultivated species, two diploid species G. arboretum and G. 

herbaceum, which evolved from Africa and the Middle East, and two allotetraploid species G. hirsutum

and G. barbadense, which evolved in the Americas (Brubaker, et al. 1999). Upland cotton (G. 

hirsutum) and Pima cotton (G. barbadense) species account for more than 95% of world cotton 

production. 

Improved modern varieties of G. hirsutum and G. barbadense are currently cultivated in the southern 

U.S., with G. barbadense grown primarily in the western states of Arizona, California, New Mexico, 

and Texas. G. hirsutum is produced throughout the 17 states comprising the U.S. cotton growing 

region. 

Commercial cotton, including G. hirsutum and G. barbadense, has a long history of agricultural 

production (Lee 1984; USDA-AMS 2001; USDA-NASS 2012c). The extra-long staple lint produced 

from G. barbadense is segregated and classed separately from G. hirsutum and is sold at a premium 

(USDA-AMS 2001). However, cottonseed and cottonseed by-products (e.g., oil and meal) are not 

generally distinguished by species (OECD 2008; USDA-FAS 2005). 

Cotton Biology and Weed Management: In contrast to other crops, including corn and soybean, 

cotton emergence and above ground growth is relatively slow during the first few weeks after 

planting. The slow early growth of cotton does not permit the crop to aggressively compete against 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 51 of 946

weed species that often grow more rapidly (Smith and Cothren 1999). Weeds in cotton are 

controlled through the diversified use of various cultural, mechanical, and chemical methods (Hake, 

et al. 1996b). Historically, mechanical tillage and hand-weeding were the most important tools in 

cotton weed control due to the limited application window afforded to most chemical applications. 

Today with the advent of GE cotton, approximately 38% of the total cotton acres are post-plant 

cultivated. In fields classified as employing conventional tillage systems, over 50% cotton acres are 

cultivated for weed control (USDA-ERS 2012c). 

Due to the biology and planting practices of cotton, in the U.S., whereby complete crop canopy 

closure is at times never achieved, herbicides are used at multiple intervals throughout the entire 

growing season on essentially all (>99%) the cotton acres in the U.S. (Brookes and Barfoot 2012; 

Monsanto 2012). Weed management and herbicide use are discussed in Section II.B.2.d. 

Cotton Use: Cotton is a crop that produces two main commodities: fiber and seed. Fiber (lint) 

accounts for approximately 85% of the crop value. The development of the mechanized cotton gin 

in 1793 greatly contributed to the value of cotton as a crop by separating the fiber from the seed and 

by removing objectionable foreign matter, while generally preserving the inherent qualities of the 

fiber and seed (Smith and Cothren 1999). Approximately 57% of the cotton fiber produced is used 

in the manufacture of apparel, 36% is used in home furnishings, and 7% is used in industrial 

products (NCCA 2010a). For every 100 pounds of fiber produced by the cotton plant, it also 

produces approximately 162 pounds of cottonseed (NCCA 2010b). Roughly one-third of the 

cottonseed is crushed for oil and meal used in food products and in livestock feed. The extracted oil 

from cottonseed is further processed to produce cooking oil, salad dressing, shortening and 

margarine. Limited quantities of the cottonseed oil are used in soaps, pharmaceuticals, cosmetics, 

textile finishes, and other products.

II.B.2.b. Land Use

Cotton Production: Cotton is a warm-season plant. Successful production requires 200 frost-free 

days and more than 160 days above 15°C. Thus, continental U.S. production is limited to the 

southern portions of the country (Waddle 1984). Two species of cotton (genus Gossypium) are 

grown in the U.S.: upland cotton (G. hirsutum), which comprises the vast majority of U.S. cotton 

production with nearly 11 million acres planted and 18 million bales harvested, and Pima cotton (G. 

barbadense), which accounted for approximately 200,000 acres and half a million bales in 2010 

(USDA-NASS 2011b). Planted acres by county are shown in Figures II.B-2 (upland cotton) and 

II.B-3 (Pima cotton).

U.S. upland cotton production occurs in 17 states, primarily across the southern portion of the U.S. 

where the climate is warmer and the season is longer (USDA-NASS 2010a). In the U.S., Pima 

cotton is grown primarily in California with small acreages in Arizona, New Mexico, and Texas 

(USDA-NASS 2013c). Cotton can be grown adjacent to or near large acre crops such as corn, 

soybeans, sorghum, wheat, peanuts, and other cotton; near vegetables, orchards, and pastures; and 

adjacent to non-agricultural lands, such as forests, grasslands, streams, lakes, and rivers; and 

occasionally near urban areas. Cotton fields are typically highly managed agricultural areas that can 

be expected to be dedicated to crop production for many years. 

Total U.S. cotton acreage since 2000 has varied from approximately 9 to 16 million planted acres, 

with the lowest acreage recorded in 2009 and the highest in 2001 (Table II.B-12). Average cotton 

yields have varied from 632 to 879 pounds per acre over this same time period (Table II.B-12). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 52 of 946

Approximately 7.6 million acres of cotton were planted in Texas in 2011, representing roughly 50% 

of the total U.S. cotton acres. Georgia was the second largest state for cotton acreage, with 1.6 

million total acres (Table II.B-13). The variations observed in cotton acreage and production are 

primarily driven by current market conditions, rather than agronomic considerations.

Herbicide-tolerant cotton was grown on 73% of U.S. cotton acres in 2011 (USDA-NASS 2013b). 

Only 3% was planted to glufosinate-tolerant cotton (USDA-NASS 2010a). GE-derived varieties of 

cotton, containing either a herbicide tolerance, insect resistance, or both traits, comprise 90% of all 

cotton acreage in 2011 (USDA-NASS 2010a; 2013b). There is no indication that the introduction 

and widespread adoption of GE-derived crops in general has resulted in a significant change to the 

total U.S. acreage devoted to agricultural production. The cumulative land area in the U.S. planted 

to principal crops, which include corn, sorghum, oats, barley, winter wheat, rye, durum, spring 

wheat, rice, soybean, peanuts, sunflower, cotton, dry edible beans, potatoes, canola, proso millet, and 

sugar beets, has remained relatively constant over the past 27 years. From 1982 to 1995, the average 

yearly acreage of principal crops was 323 million. This average is essentially unchanged at 326 

million acres since the introduction of GE-derived crops in 1996 (USDA-NASS 1984; 1990; 1992; 

1995; 1998; 2000; 2003; 2006; 2009a).

For the purposes of this environmental report, cotton production is divided into four major cottongrowing regions: Southeast (AL, FL, GA, NC, SC, and VA), Midsouth (AR, LA, MS, MO, and TN), 

Southwest (KS, NM, OK, and TX), and West (AZ and CA) (Table II.B-13).

Seed Production Areas: Seed is produced in the same general areas as the cotton crop. The 

majority of the cotton seed crop is produced in Texas, with significant quantities produced in 

Arizona, Arkansas, California, and Mississippi (McDonald and Copeland 1997). Seed companies 

minimize the risk of crop loss due to weather events by producing seed in multiple regions.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 53 of 946

Figure II.B-2. Planted Upland Cotton Acres by County in the U.S. in 2012

(USDA-NASS 2013d). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 54 of 946

Figure II.B-3. Planted Pima Cotton Acres by County in the U.S. in 2012

(USDA-NASS 2013c).
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Table II.B-12. Cotton Production in the U.S., 2000-20111

Year

Acres 

Planted

(×1000)

Acres 

Harvested

(×1000)

Average 

Yield

(lbs/acre)

Total

Production

(480 lb bales)

Value

(billions $)

20112

2010

14,735

10,973

9,461

10,707

790

821

15,573,200

18,314,500

7.262

7.318

2009 9,150 7,529 777 12,187,500 3.788

2008 9,471 7,569 813 12,815,300 3.021

2007 10,827 10,489 879 19,206,900 5.653

2006 15,274 12,732 814 21,587,800 5.013

2005 14,245 13,803 831 23,890,200 5.695

2004 13,659 13,057 855 23,250,700 4.994

2003 13,480 12,003 730 18,255,200 5.517

2002 13,958 12,417 665 17,208,600 3.777

2001 15,769 13,828 705 20,302,800 3.122

2000 15,517 13,053 632 17,188,300 4.260

1

(USDA-NASS 2011e).

2

(USDA-NASS 2012b).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 56 of 946

Table II.B-13. U.S. Cotton Production by Region and State in 20111

Region/State

Acres Planted

(thousands)

Acres Harvested

(thousands)

Average Yield

(pounds/acre)

Alabama 460 447 762

Florida 122 120 660

Georgia 1,600 1,520 805

North Carolina 805 800 630

South Carolina 303 301 773

Virginia 116 115 689

Region Totals 3,406 3,303 720

Arkansas 680 660 938

Louisiana 295 290 852

Mississippi 630 605 968

Missouri 375 367 961

Tennessee 495 490 813

Region Totals 2,475 2,412 906

Kansas 80 68 494

New Mexico 68 62 1,084

Oklahoma 415 70 432

Texas 7,550 3,100 542

Region Totals 8,113 3,300 638

Arizona 250 248 1,526

California 637 634 1,399

Region Totals 887 882 1,463

U.S. Total 14,881 9,897 932

1

(USDA-NASS 2012b).

II.B.2.c. General Agronomic Practices

Life Cycle: Botanically, cotton is a perennial that is cultivated as an annual (Smith and Cothren 

1999). Depending on the region and variety, cotton is planted in the U.S. between April and June 

and harvested between September and December (USDA-NASS 2010b). Cotton is normally 

considered to be a self-pollinating crop (Niles and Feaster 1984), although a low level of natural 

outcrossing has the potential to occur. Cotton pollen movement by wind is very limited due to it is 

large and sticky nature; several studies have demonstrated that cross-pollination, even in the 

presence of high pollinator activity, is limited by distance (OECD 2008) (see Subsection II.D.2.c for 

additional details). 

Varieties: In a given year, more than 100 different cotton varieties are grown in the U.S. (USDAAMS 2012a), with new varieties introduced every year. Varieties are evaluated in performance tests 

(variety trials) that are conducted across the cotton-growing region. Lint (fiber) yield potential has 

generally been the most important factor considered by growers in variety selection (Smith and 
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Cothren 1999). Growers also consider properties such as fiber length and strength, cold tolerance, 

seedling vigor, heat tolerance, leaf hairiness, insect and disease resistance, herbicide tolerance, storm 

resistance, maturity, and a number of other factors when selecting commercial varieties. 

Water Use: Depending upon the U.S. cotton growing region and access to supplemental irrigation 

the water requirement for cotton to produce high yields varies. The humid Southeast region of the 

U.S. requires a minimum of 18 inches of water per year to produce maximum yields (Bednarz, et al. 

2002). The desert Southwest region requires a maximum of roughly 40 inches of water per year 

(Hunsaker 1999). The water requirements of cotton are greater than the annual rainfall in the U.S. 

west of Central Texas; irrigation is a key component of the cotton production system to maximize 

yield. Approximately 45% of the cotton production in the U.S. is irrigated (USDA-ERS 2007). 

Yields: The yield potential of a cotton crop is determined in the first 30 to 40 days after seed is 

placed in the ground (Deterling and El-Zik 1982). Planting date management is an important step 

to getting the crop established, achieving early fruit set, and establishing a strong yield potential 

(Smith and Cothren 1999). Cotton should be planted into prepared seedbeds that are firm, warm, 

and moist. Early season insect and mite damage, or damage to the terminal bud from hail, insects, 

or equipment, can negatively impact yields. The period between first bloom and the cessation of 

vegetative growth is the period when the greatest potential in crop yield is either gained or lost. 

Approximately 85% of the total bolls that are harvested come from floral buds (squares) set during 

the first four to five weeks of squaring (Deterling and El-Zik 1982). Production practices are 

optimized to favor reproductive growth at the expense of vegetative growth. Available options to 

influence cotton plant growth include the use of a plant growth regulator(s) such as mepiquat 

chloride, fertility management (primarily nitrogen and potassium), and overall water management. 

In addition, insect pest control is important throughout the growing season as pest populations 

exceed economic thresholds which dramatically decrease both square and immature boll retention. 

Weed control is equally important throughout the growing season to maximize yields by eliminating 

weeds that complete for available light, water, and nutrients.

Average 2011 cotton yields across the four cotton-growing regions ranged from 638 to 1463 pounds 

of cotton lint per acre, with the highest yields in the West with full irrigation, and the lowest yields in 

areas such as Kansas, Oklahoma, and Texas, where little to no irrigation is available (Table II.B-13). 

Crop Nutrition: Thirteen essential minerals and nutrients are needed for cotton growth and 

development. Nitrogen is the nutrient to which cotton most consistently responds (Mullins and 

Burmester 2010). The key to management of nitrogen in the soil is to provide adequate amounts to 

correct deficiencies, but not excess amounts. Excess nitrogen fertilization can promote excess 

vegetative growth (at the expense of fruiting) and delayed maturity, which results in lower yields 

(Smith and Cothren 1999). In the Southwest and West regions, monitoring soil salinity is of 

additional importance because cotton is most sensitive to salts during the germination and seedling 

growth stage (Hake et al. 1996b). Soil salinity will severely delay emergence, which can make the 

plants more vulnerable to seedling disease. Pre-season soil test results for nitrogen, phosphorus, and 

potassium, determination of pH, and previous cropping and fertilization history determine the 

fertilizer and liming needs for the upcoming cotton crop.

Use of Plant Growth Regulators: Cotton is a perennial and has an indeterminate growth pattern 

(i.e. flowering and fruiting does not occur all at once, but rather it is an ongoing process that 

continues until harvest or frost). A consequence of this growth habit is that vegetative and 

reproductive growth occur at the same time and thus compete for photosynthetic products (Norton 
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and Silvertooth 2000). Cotton growers commonly used mepiquat chloride and other plant growth 

regulators to control vegetative growth and thereby enhance reproductive growth (Norton and 

Silvertooth 2000). 

Crop Rotation: Cotton rotation with other crops on a regular basis can help maintain soil 

productivity and reduce the incidence of various weeds, insect pests, or diseases (Hake et al. 1996b). 

Rotating cotton with monocot crops, such as corn, can help to reduce the soil inoculum level of the 

seedling disease fungi Pythium and Rhizoctonia. These seedling diseases can increase in continuous 

cotton cropping systems (Smith and Cothren 1999). However, production costs, relative rate of 

return, and the current market conditions dictate which crops to rotate with cotton or whether to 

grow continuous cotton. These economic factors may outweigh the agronomic benefits of crop 

rotation. In 2003, the USDA reported that cotton was grown in a continuous cropping system on 

73% of the acreage in the major cotton-growing states (Norton and Silvertooth 2000; USDA-ERS 

2006). However, more recent state-specific information from interviews with university extension 

crop production specialists and extension weed control specialists indicates that the percentage of 

cotton acres in continuous cropping is decreasing across the Cotton Belt. Based on interviews 

conducted by Monsanto in 2010, approximately 54% of U.S. cotton acres are followed by cotton in 

the crop rotation sequence. By region, this percent is highest in the Southwest (61%) and lowest in 

the West (30%). Only in the West region is cotton rotated to another crop, wheat, on the majority 

of cotton acres. Corn (16%), wheat (9%), soybean (8%), sorghum (8%), and peanuts (4%) are the 

other crops most frequently following cotton. When rotational crops are planted, the most 

common rotation crops by region are as follows: Southeast, soybean; Midsouth, corn; Southwest, 

sorghum; and West, wheat. 

Winter cover crops are also utilized in cotton production. These cover crops are used to provide 

winter soil cover and protection, build soil nitrogen and organic matter, reduce nitrogen leaching, 

suppress weeds, and provide a habitat for beneficial predatory and parasitic insects and spiders 

(Guerena and Sullivan 2003).

Soil Types: Cotton has broad adaptability to a wide range of soil types, provided that sufficient 

nutrition and moisture are available through the growing season (Hake and Kerby 1996). In general, 

where annual rainfall is less than 20 inches, fine-textured soils (loam and clay loam) will be more 

productive because of their ability to store water in the soil profile. Where rainfall exceeds 30 inches 

per year, coarse-textured soil provides better internal drainage and greater productivity. 

Preharvest and Harvest: Defoliants are applied prior to harvesting, as the complete removal or 

desiccation of leaf tissue in preparation for harvest is a necessity with machine harvesting (Hake, et 

al. 1996a). An additional objective of defoliation is to control or desiccate weeds that can reduce 

harvest efficiency, contribute to the weed seed bank, and reduce both the quality and value of the 

lint because of staining by vegetation (University of Georgia 2012). 

Tillage: Tillage is used for seedbed preparation and may also be used for weed control. The 

primary purposes of preplant tillage are to incorporate residue from the previous crop, reduce wheel 

traffic compaction from the previous season, improve water filtration and soil aeration, control 

weeds, loosen the soil for root penetration, and provide a suitable environment for the planting and 

germination of cottonseed (Hake et al. 1996b). Decreased profitability in cotton production, as well 

as soil erosion concerns, have increased interest in conservation tillage systems. The benefits of 

conservation tillage or no-till systems are well documented and include reduced soil erosion, reduced 

fuel and labor costs, improved soil tilth (including structure improvement and reduction in 
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compaction), increased organic matter, improved water quality, and conservation of soil moisture 

(CTIC 2011). 

Conventional tillage is associated with intensive plowing and less than 15% crop residue at the soil 

surface; reduced tillage is associated with 15 to 30% crop residue; and conservation tillage, including 

no-till practices, is associated with at least 30% crop residue and substantially less soil erosion than 

other tillage practices (CTIC 2010; U.S. EPA 2010a). As of 2008, approximately 21% of cotton 

acres were planted in a conservation tillage system, which included no-tillage, mulch-till, and reduced 

tillage systems (CTIC 2010). Over 17% of the cotton acres were in no-tillage systems which rely 

solely on chemical means for weed control. The adoption of glyphosate-tolerant cotton has 

facilitated the transition from conventional tillage to conservation tillage systems over the last decade 

(Givens, et al. 2009b). Increases in total acres dedicated to conservation tillage have been attributed 

to increased planting of herbicide-tolerant cotton, which reduces the need for mechanical weed 

control (McClelland, et al. 2000; Towery and Werblow 2010). 

Some growers have been slow to transition to conservation tillage systems because of equipment 

costs, compaction, flooding or poor drainage, delays in planting because fields are too wet or too 

cold, or carryover of diseases or pests in crop residue (Shurley 2006). However, in a 2000-2004 

USDA Mississippi study that compared net economic returns with five different tillage methods, the 

no-till treatment regime (without cover crops) resulted in the highest returns per acre, primarily due 

to the reduction in the number of trips across the field (Perry 2009). 

As a result of weed shifts and the existence of weeds resistant to glyphosate and other herbicides in 

certain areas of the U.S., there is the potential for the loss of soil conservation gains resulting from 

conservation tillage, because of the need to manage such weeds through additional means, including 

tillage. For example, mechanical methods (machine tillage or hand-weeding) have been found to be 

one of the few consistent control options for Palmer amaranth, which has become a frequent hardto-control weed in certain areas of southeastern cotton production (CAST 2012). 

II.B.2.d. Pest Management

The use of pesticides, including fungicides, herbicides, and insecticides, is a key component of an 

integrated pest management (IPM) system in cotton. The various pesticides used in cotton, along 

with other IPM elements, are addressed in the two subsections below.

Disease Management: Plant pathologists have estimated that diseases cause annual losses in U.S. 

cotton production of 1.8 million bales, which represents a yield reduction of approximately 9.0% 

(Blasingame, et al. 2008). Cotton must be protected from diseases during the early period of slow 

growth to prevent yield loses (Smith and Cothren 1999).

The major seedling diseases are caused by fungal pathogens that occur on or in cottonseed prior to 

planting and soil-borne pathogens that reside in soil (Smith and Cothren 1999). The soil-borne 

pathogens are the most important causes of seedling disease and the most difficult to control. Other 

fungal pathogens cause wilt diseases, resulting in yield losses. Verticillium and Fusarium wilt are the 

two major fungal wilt diseases which result in yield loss in cotton production. Phymatotrichum root 

rot, macrophomina root rot, Agrobacterium root rot, and root gall are the primary pathogens that may 

attack the roots of older cotton plants (Smith and Cothren 1999). The foliar diseases are caused by 

fungal and bacterial pathogens that infect leaves, stems, bolls, and occasionally seedling roots. 
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Bacterial blight, boll rot, fungal leaf spots, fungal boll rots, viran, and mycoplasmal make up the 

primary foliar diseases.

An integrated management system, utilizing agronomic and cultural practices, is the best means of

controlling disease in cotton, including the selection of resistant varieties, and applications of 

biocontrol agents (Smith and Cothren 1999). The single most important practice for minimizing 

damage from seedling diseases is selection of high-quality planting seed that has minimal seed coat 

damage and high germination rates (Smith and Cothren 1999). Seedbed conditions that encourage 

rapid germination and emergence will minimize seedling disease losses (NCCA 2007). Various 

cultural practices such as crop rotation, proper fertility and water management, clean tillage systems, 

early planting, eliminating weeds (which are host plants to the pathogen), and practices that increase 

decomposition of crop residues can reduce the severity of diseases (Smith and Cothren 1999). 

Cottonseed is normally treated with a mixture of fungicides and biological control agents to protect 

seeds and seedlings from seed- and soil-borne pathogens during their first few weeks of growth. 

Fungicides are also used to prevent spread of foliar diseases when these infestations approach 

economically damaging levels. An average of three fungicide treatments were made in cotton in 

2007 (USDA-ERS 2012a). Foliar fungicides are applied to approximately 3% of the cotton acreage 

(USDA-NASS 2008c). 

Management of Insect and Other Pests: Insect and mite pests, which can result in decreased 

yield and reduced quality, are a common and continuous threat to cotton production in all regions 

where it is produced in the U.S. Nearly every stage of cotton growth is susceptible to injury; as a 

consequence, cotton fields must be monitored regularly. Insects caused yield losses of 

approximately 986 thousand bales of cotton in 2010, equating to a 3.9% yield loss (Williams 2010). 

Lepidopteran pests, specifically tobacco budworm and cotton bollworm result in the greatest yield 

reductions followed by stink bugs and lygus insects. 

Successful and economical management of insect pests in cotton is accomplished through an 

integrated pest management approach of variety selection and implementation of cultural, biological, 

and chemical strategies (University of Georgia 2011). Preplant tillage and crop rotation are 

important agronomic and cultural practices utilized to reduce insect populations prior to planting 

cotton. Other agronomic practices are utilized to promote early maturity and reduce that period of 

time the crop is susceptible to insect and mite pests, and to increase the probability that an 

acceptable yield can be produced before insect pest densities exceed economic threshold levels 

(Smith and Cothren 1999). Selection of short-season determinate varieties, adherence to optimum 

planting periods, and early season insect and disease management strategies can shorten the 

production season and limit crop exposure to late season insect pressure. In addition, 

implementation of conservation tillage systems usually provide timely planting and crop 

management, to promote an earlier-maturing crop. Conservation tillage systems mediate soil 

moisture and temperature conditions to decrease the probability of delays in planting caused by 

adverse weather conditions (Smith and Cothren 1999). Biological control involves the importation, 

conservation, and/or augmentation of natural enemies (predators, parasites, and pathogens) of 

insect pests of cotton and is a major component of integrated pest management programs in cotton 

production (Smith and Cothren 1999). 

The annual application of insecticide to cotton has decreased from 10-20 insect treatments per year 

to four to five treatments since the successful elimination of the boll weevil as an economic pest and 

the commercialization of insect-protected Bt cotton varieties in 1996 (University of Georgia 2012). 
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GE insect-protected cotton varieties were used on approximately 65% of the planted acres of cotton 

in 2011 (USDA-NASS 2012e).

Insecticides were applied to 66% of the U.S. cotton acreage in 2007, with an average of three 

insecticide treatments per treated acre (USDA-NASS 2008c). 

In addition to cotton insect and mite pests, nematodes are present throughout the Cotton Belt and 

cause significant loss of yield and impact fiber quality. Nematodes are microscopic, wormlike 

animals that feed on cotton roots. Yield losses in cotton from nematodes exceed $400 million 

annually in the U.S (NCCA 2007). Management options are primarily pre-season and include 

planting tolerant or resistant cotton varieties, crop rotation, cultural practices and the use of a 

nematicide (NCCA 2007). 

Weeds in Cotton: Across the Cotton Belt many annual and perennial weeds occur, resulting in 

economic damage to cotton yield, fiber quality, and economic returns. Barnyardgrass, crabgrass, 

pigweed spp. (including Palmer amaranth), morningglory spp., common cocklebur, and common 

lambsquarters are common annual weed species in almost all cotton-growing regions. Johnsongrass, 

bermudagrass, and nutsedge are common perennial weed species. Nightshade spp. and 

groundcherry are more common in the Southwest and West regions. Palmer amaranth, 

morningglory spp., and nutsedge spp. have been frequently reported as hard-to-control weed species 

in cotton (Webster et al. 2009). Tables II.B-14 through II.B-17 summarize the most common weeds 

for each of the four major cotton growing regions (Southeast, Midsouth, Southwest and West).

Table II.B-14. Common weeds in Cotton Production in the Southeast Region of the U.S.1,2

Crabgrass spp. (6) Pigweed spp (3) Crowfootgrass (1)

Morningglory spp (6) Common cocklebur (2) Horseweed (marestail) (1)

Prickly sida (5) Common lambsquarters 

(2)

Jimsonweed (1)

Florida pusley (4) Common ragweed (2) Johnsongrass (1)

Nutsedge spp. (4) Florida beggarweed (2) Smartweed spp. (1)

Sicklepod (4) Palmer amaranth (2) Spurge spp (1)

Broadleaf signalgrass (3) Texas millet (2) Volunteer peanut (1)

Goosegrass (3) Bermudagrass (1)

1 Source: (Webster et al. 2009). 

2 Number provided in parenthesis is the number of states out of the six total states (AL, FL, GA, NC, SC, & VA) in the Southeast 

Region reporting each weed as one of the ten most common weeds.
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Table II.B-15. Common weeds in Cotton Production in the Midsouth Region of the U.S.1,2

Morningglory spp (5) Velvetleaf (3) Common cockleburr (1)

Broadleaf signalgrass (4) Barnyardgrass (2) Cutleaf evening-primrose (1)

Crabgrass spp (4) Horseweed (marestail) (2) Goosegrass (1)

Nutsedge spp (4) Johnsongrass (2) Hemp sesbania (1)

Prickly sida (4) Palmer amaranth (2) Henbit (1)

Spurge spp (4) Bermudagrass (1) Spurred anoda (1)

Pigweed spp (3) Browntop millet (1)

1 Source: (Webster et al. 2005; Webster et al. 2009) Webster et al., 2005 (MS & TN); Webster et al., 2009 (AR, LA, & MO).

2 Number provided in parenthesis is the number of states out of the five total states (AR, LA, MS, MO, & TN) in the Midsouth 

Region reporting each weed as one of the ten most common weeds.

Table II.B-16. Common weeds in Cotton Production in the Southwest Region of the U.S.1,2

Johnsongrass (4) Pigweed spp (2) Smartweed (1)

Nutsedge spp (4) Russian thistle (2) Smellmelon (1)

Common cockleburr (3) Barnyardgrass (1) Spurred anoda (1)

Palmer amaranth (3) Bermudagrass (1) Red Sprangletop (1)

Silverleaf Nightshade (3) Bindweed, field (1) Sunflower (1)

Common lambsquarters (2) Foxtail spp (1) Texas blueweed (1)

Large Crabgrass (2) Groundcherry spp (1) Texas millet (2)

Devil’s claw (2) Kochia (1) Velvetleaf (1)

Morningglory spp (2) Horseweed (marestail) (1) Woolyleaf bursage (1)

Mustard spp (2) Shepardspurse (1)

1 Source: OK - Webster et al., 2009; KS – Dr. Stewart Duncan, Kansas State University – Personal Communication 11/4/2010; 

NM – Dr. Jamshid Ashigh, New Mexico State University – Personal Communications 11/12/2010; TX – Dr. Wayne Keeling 

and Dr. Gaylon Morgan, Texas A&M University - Personal communications 11/4/2010.

2 Number provided in parenthesis is the number of states out of the four total states (KS, OK, TX, & NM) in the Southwest 

Region reporting each weed as one of the ten most common weeds.

Table II.B-17. Common weeds in Cotton Production in the West Region of the U.S.1,2

Barnyardgrass (2) Common lambsquarters (1) Silverleaf Nightshade (1)

Morningglory spp (2) Johnsongrass (1) Palmer amaranth (1)

Sprangletop (2) Junglerice (1) Common Purslane (1)

Bermudagrass (1) Nutsedge spp (1) Horse Purslane (1)

Field Bindweed (1) Pigweed spp (1) Volunteer corn (1)

Cupgrass, southwestern (1) Black Nightshade (1)

Groundcherry spp (1) Hairy Nightshade (1)

1 Source: AZ – Bill McCloskey, University of Arizona – Personal Communication 11/5/2010; CA – Steven Wright, University of 

California - Personal Communication 11/16/2010.
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2 Number provided in parenthesis is the number of states out of the two total states (AZ & CA) in the West Region reporting 

each weed as one of the ten most common weeds.

Benefits of Herbicide Use in Agriculture: A study by CropLife America demonstrated that in 

2005 the use of herbicides saved U.S. farmers 337 million gallons of fuel, produced $16 billion in 

crop yield increases, and cut weed control costs by $10 billion as compared to production without 

the use of herbicides (Gianessi and Reigner 2006). Additionally, without herbicides growers would 

have to abandon no-till production practices, which reduce soil erosion. If U.S. growers stopped 

using herbicides and resumed tillage on the number of acres not tilled in 2005, an additional 356 

billion pounds of sediments would be deposited in streams and rivers, resulting in an estimated $1.4 

billion in downstream damage (Gianessi and Reigner 2006). 

Weed Management in Cotton: Weed control in cotton is essential to maximize both yield and 

quality of cotton fiber. The slow early growth of cotton does not permit the crop to aggressively 

compete against weed species that often grow more rapidly and utilize the available water, nutrients, 

light, and other resources for growth (Smith and Cothren 1999). Cotton yields can be reduced 

substantially if weeds are uncontrolled. Palmer amaranth has been reported to cause yield losses as 

high as 54% (Morgan, et al. 2001) and johnsongrass and barnyardgrass have been reported to reduce 

yields by 90% and 98%, respectively (Vargas et al. 1996). Based on 2005 data, not using herbicides 

in cotton would result in an increased production cost of approximately $2.3 billion annually and an 

estimated yield loss of 27% (Gianessi and Reigner 2006). 

Weed-crop competition studies have demonstrated that the control of weeds during the first four to 

eight weeks after cotton planting is critical as weeds compete against the crop for water, nutrients, 

light and other resources necessary for growth (Smith and Cothren 1999). The primary weed 

competition factors affecting yield loss potential are the weed species, weed density, and the 

timing/duration of weed competition. Cotton emergence and above ground growth is relatively 

slow during the first few weeks after planting, and does not permit the crop to aggressively compete 

against often more rapidly developing weed species (Smith and Cothren 1999). In addition, cotton 

is primarily planted using wide row spacing which delays crop canopy closure until layby stage of 

cotton and extends the window of weed-crop competition. 

While late-season infestations may not impact yield, they reduce harvesting efficiency, contribute to 

the weed seed bank and lower the lint grade (McWhorter and Bryson 1992; Vargas et al. 1996). 

Weeds can also increase cotton disease and insect management issues because certain weed species 

can be a host for pathogens, such as Rhizoctonia and Verticillium, and harbor insects such as lygus 

bugs. 

The most effective weed management programs in cotton use diversified weed management

practices, a combination of cultural, mechanical, and/or herbicide control practices, instead of 

relying on one particular method of weed control (Beckie et al. 2011; Norsworthy, et al. 2012; 

University of California 2009; Vargas et al. 1996). Herbicide application practices that are 

compatible with diversified weed management include the use of several herbicides with different 

modes-of-action, either within or across seasons, applying herbicides at the labeled rate at the 

correct timing, and proper application of the herbicide. Cultural and mechanical practices can also 

be important components of an effective diversified weed management program (Ashigh et al. 

2012). Cultural practices such as crop rotation, use of optimal planting dates, and the use of cover 

crops, when implemented, can increase the crop’s ability to compete with weeds. Crop rotation 
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(limiting continuous cotton planting), in conjunction with other weed control methods, can play a 

role in the overall weed spectrum and can drastically reduce the overall weed population observed 

(Smith and Cothren 1999). Approximately 38% of the total cotton acres are post-plant cultivated 

for weed control and in conventional tillage systems, and over 50% of cotton acres are cultivated for 

weed control with as many as five tillage operations occurring after emergence to harvest (USDAERS 2012c). Spring preplant or fall postplant tillage and in-crop shallow cultivation can effectively 

reduce the competitive ability of weeds. A consequence of in-crop cultivation for weed control is 

that tillage equipment can damage crop roots or apical meristem, cause soil moisture loss. More 

recently, cotton growers have begun utilizing more hand-weeding to control glyphosate-resistant

Palmer amaranth in fields. For example, Georgia cotton growers have increased hand-weeding from 

17% of the state cotton acreage in 2000-2005 to 52% of the acreage in 2006-2010. Hand-weeding 

has current cost of $23 per acre (Sosnoskie and Culpepper 2012). A survey of Georgia cotton 

growers conducted in 2010 found that 92% of growers spent $16 million on hand-weeding 53% of 

the total Georgia cotton crop; similarly, at least 20% of the cotton acres in Tennessee were handweeded at cost of more than $3 million (Culpepper, et al. 2011). 

The planting of winter cover crops can be utilized as part of a diversified weed management 

strategy. The planting of cover crops, such as grasses, legumes, or small grains can protect and 

improve soil quality, help reduce erosion, serve as surface mulch in no-till cropping practices, and 

provide habitat for beneficial insects (Guerena and Sullivan 2003; Hitt and Roos 2007; Mannering et 

al. 2007). Small grain crops such as rye are commonly used as a cover crop; incorporating rye or 

oats as a cover crop have been shown to suppress Palmer amaranth germination and growth (Price, 

et al. 2011). However the planting of cover crops in general incurs additional costs to the grower 

and therefore cover crops are not presently a major weed management practice utilized in cotton 

production systems (Singer 2006). 

Herbicides are used on essentially all (>99%) cotton acres, and in 2011 approximately 39 million 

pounds of herbicides were applied pre- or postemergence in cotton production (Brookes and 

Barfoot 2012; Monsanto 2012). According to 2010 market data36, there were approximately 46.3 

million herbicide-treated cotton acres. Herbicides were applied to 21.8 million acres prior to the 

planting or emergence of cotton (preemergent) and to 24.5 million acres after the emergence of 

cotton (postemergent). For clarification, the market survey data counts one treated acre as the 

application of one active ingredient (a.i.) one time to an acre. If the same a.i. is applied a second 

time to that same acre or if two a.i.s are applied, it counts as two treated acres. USDA reports that 

11.0 million acres of cotton were planted in 2010,37 so that the 46.3 million herbicide-treated cotton 

acres means that on average each planted acre received at least 4 herbicide treatments. Cotton acres 

also received on average four treatments with herbicides during the 2011 growing season (USDAERS 2012a). 

Of these treatments, 50% (23.3 million acres) were made with glyphosate herbicides, and the 

remaining 50% of treatments were made with more than 25 other active ingredients. The number of 

 

36 Monsanto Company. 2011. Farmer Survey Data. St. Louis, MO.

37 USDA Statistics for crops and geographic regions are available at http://www.nass.usda.gov/index.asp.
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glyphosate applications on an average cotton acre was between 2 and 3 applications per year at an 

average rate of 2.0 pounds acid equivalent (a.e.) of glyphosate active ingredient per acre per crop 

year. 

Herbicide-tolerant cotton is planted on the majority of U.S. cotton acres (73% in 2011), which 

allows for the postemergence in-crop use of glyphosate for control a broad spectrum of weeds. 

Glyphosate is the most widely used herbicide in cotton, applied on 91% of cotton acres with an 

average of 2.4 applications per growing season (Monsanto 2012). In 2010, between 49 and 76% of 

the growers who plant glyphosate-tolerant (GT) cotton applied non-glyphosate herbicides prior to 

planting, at planting, or postemergence. Percentages varied among cropping systems, with 76% of 

GT cotton in a rotation system with GT soybean receiving non-glyphosate herbicide applications, 

whereas non-glyphosate herbicides were only applied 49% of the time in continuous cotton 

cropping systems (Prince, et al. 2011a). Non-glyphosate herbicides with different modes-of-action 

are also frequently used to provide residual weed control, improve control on certain weed species, 

and extend weed control or control resistant weed species (Prince et al. 2011a). The non-glyphosate 

herbicides applied, on cotton in 2011, included ALS inhibitors (trifloxysulfuron, pyrithiobac), 

longchain fatty acid inhibitors (acetochlor, metolachlor), microtubule inhibitors (pendimethalin, 

trifluralin), PSII inhibitors (prometryn, fluometuron, diuron), PPO inhibitors (flumioxazin, 

fomesafen), synthetic auxins (2,4-D, dicamba), glufosinate, MSMA and paraquat (Monsanto 2012).

In 2010, dicamba-treated acres in cotton accounted for only 0.85 million acres, or 3.9% of the total 

preemergent treated acres.38 This is primarily because dicamba is phytotoxic to current cotton 

varieties and is currently only labeled for application at timings that avoid contact with the growing 

plant, such as preplant treatments prior to planting, depending on rate and rainfall.

Over 30 different herbicide active ingredients are registered and available for use by cotton growers 

to control weeds. The ten most widely used alternative herbicides in cotton in 2010 are listed in 

Table II.B-18, compared to 2007 use. Integration of DGT cotton into the glyphosate-tolerant

cotton system and the subsequent use of dicamba will result in the displacement of some currently 

used, or foreseeable future use herbicides, and therefore the properties of these alternative 

herbicides are summarized in this section to provide a baseline for comparison to dicamba use on 

DGT cotton. Some non-glyphosate alternative herbicides have a less benign human health and 

environmental characteristics compared to dicamba, and reduced agronomic flexibility due to cotton 

planting restrictions, rotational crop planting restrictions, the need for adequate soil moisture for 

activation, and the need to apply prior to planting or with hooded sprayers in-crop to minimize crop 

injury.

39

 

 

38 Monsanto Company. 2011. Farmer Survey Data. St. Louis, MO.

39 In order to approve a new use of a herbicide EPA must conclude that the herbicide, when used according to the label, does not 

pose an unreasonable adverse effect to humans or the environment, and, in order to establish a tolerance for the use of a 

herbicide on a food or feed crop, find there is a reasonable certainty of no harm to human health from non-occupational (food, 

water and residential/recreational) exposures to the herbicide. Therefore, all alternative herbicides used in cotton production can 

be used safely, and do not pose an unreasonable risk to humans or the environment.
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Table II.B-18. Ten Most Widely Used Alternative Herbicides in U.S. Cotton Production

Herbicide 2007 Applications (million 

lbs)1

2010 Applications 

(million lbs)1

Trifluralin 2.8 3.1

Diuron 1.3 1.3

Pendimenthalin 1.3 1.2

S-metolachlor 0.6 1.1

Prometryn 0.6 0.4

2,4D, dimethylamine salt 0.3 0.4

Fluormeturon 0.3 0.4

MSMA 0.4 0.3

Fomesafen 0.05 0.2

2,4-D, ethylhexyl ester 0.1 0.1

1(USDA-NASS 2012d)

Soil residual herbicides play an important role in cotton weed management by providing control of a 

number of weeds species that continuously germinate in cotton prior to canopy closure (Wilcut, et 

al. 2003). Soil residual herbicides, such as pendimethalin, trifluralin, diuron, fluometuron, 

acetochlor, and metolachlor, are applied to more than 40% of the current cotton acres (Monsanto 

2012). In addition, many of the soil residual herbicides are limited by application restrictions, plantback restrictions, the need for adequate soil moisture for activation, and the need to apply prior to 

planting or with hooded sprayers in-crop to minimize crop injury. Approximately 20% of growers 

applied a fall residual herbicide to control weeds prior to planting the following spring, and 60% 

(continuous cotton system) to 75% (GR cotton/GR soybean rotation) applied a mixture of 

glyphosate and a synthetic auxin herbicide (2,4-D or dicamba) as a spring burndown application 

(Prince et al. 2011a). Post emergent residual herbicides, such as metolachlor and acetochlor, were 

applied on over 25% of cotton acres in 2010 (Monsanto 2012). 

Further details on the use of non-glyphosate herbicides in cotton producing states can be found in 

Prince et al. (2011a; 2011c), where it is reported that approximately 50% of surveyed growers who 

did not have glyphosate-resistant weeds on their farm used a non-glyphosate residual and/or 

postemergence herbicide in the 2009 growing season. For growers who have on-farm herbicideresistant weed populations, the percentage of growers was higher, with 72% to 75% reporting the 

use of non-glyphosate herbicides. Older studies report that approximately 40 to 50% of the growers 

utilizing glyphosate-tolerant crops indicate that applying herbicides with different modes-of-action in 

sequence, rotating herbicides with different modes-of-action across the season, or tank mixing 

glyphosate with other herbicide modes-of-action are effective management practices to minimize the 

evolution and/or development of glyphosate resistance (Beckie 2006; Beckie and Reboud 2009; 

Diggle et al. 2003; Powles et al. 1996). The use of non-glyphosate herbicides in cotton production is 

expected to continue to increase as more growers adopt more diversified weed management 

strategies. Refer to Appendix A for details on alternative herbicides used in cotton production.

Dicamba Herbicide Use: Dicamba is a broadleaf selective herbicide that was approved by the 

U.S. Environmental Protection Agency (EPA) for agricultural application uses in 1967 (U.S. EPA 

2009d). Dicamba is formulated as a standalone herbicide product and marketed by several 
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companies under various trade names such as Banvel®, Clarity®, Diablo®, Rifle®, Sterling®, and 

Vision®. These dicamba products can also be tank-mixed with one or more active ingredients 

depending on the treated crop. For example, Clarity®can be tank mixed with over 75 herbicide 

products in labeled crops. Additionally, dicamba is currently formulated as a premix product with 

one or more other herbicide active ingredients, including glyphosate, 2,4-D, diflufenzopyr, atrazine, 

nicosulfuron, metsulfuron, primsulfuron, triazulfuron, rimsulfuron, and halosulfuron. 

Dicamba is currently labeled for weed control in corn, soybean, cotton, sorghum, wheat, barley, 

oats, millet, pasture, rangeland, asparagus, sugarcane, turf, grass grown for seed, conservation reserve 

programs, and fallow croplands. Dicamba-treated acreage has ranged from 17.4 to 36.3 million 

acres between 1990 and 2011. Usage of dicamba peaked during the period of 1994 through 1997, 

where 1994 was the peak year when 36 million crop acres were treated with 9.4 million pounds of 

dicamba. Since then, the use of dicamba has steadily declined to 17.4 million treated acres with 2.7 

million pounds applied in 2006. The reduction in dicamba use has been attributed to the 

competitive market introductions of sulfonylurea herbicides (chlorsulfuron, metsulfuron-methyl, and 

thifensulfuron-methyl) in wheat, new broadleaf herbicide active ingredients in corn, and 

introduction of glyphosate-tolerant corn. More recently, however, dicamba-treated acres have been 

on the rise and have increased by as much as 7.9 million acres from 2006 to 2011. Most of this 

increase has occurred in fallow, pastureland, sorghum, and cotton (preplant) (Monsanto 2012). 

Based on farm survey data generated in 2011 by a private market research company, dicamba 

application rates across agricultural row crops ranged from 0.07 to 0.27 pounds per acre with the 

average number of applications ranging from 1 to 1.4 applications per cropping season (Monsanto 

2012). Dicamba rates (pounds per acre) are lowest in spring wheat where more than one application 

is typically made per cropping season. 

Dicamba is currently labeled for use in cotton although its use is limited to preplant applications due 

to cotton’s susceptibility to dicamba. Consequently, the average application rate preplant in cotton 

is 0.26 pounds of dicamba per acre with one application per season. Dicamba preplant use in cotton 

has been on the rise in recent years, increasing from 140,000 acres in 2004, to 590,000 acres in 2008, 

and 1.4 million acres, or 9.6% of U.S. cotton acres, in 2011 (Monsanto 2012). This is primarily 

because it is a leading recommended herbicide for control of glyphosate-resistant marestail and 

Palmer amaranth in the Southeast and Midsouth region (AgWatch 2011; McClelland, et al. 2006; 

University of Georgia 2012). 

Dicamba belongs to the auxin class of herbicides, which is the oldest class of known synthetic 

herbicides. This class includes 2,4-D, 2,4-DB, mecoprop, MCPA, clopyralid, and several other active 

ingredients, and is WSSA Herbicide Group Number 4 (HRAC 2009).

40

 On the basis of their 

structural and chemical properties, auxinic herbicides have been classified into several sub-groups, 

viz., phenoxyalkanoic acids (e.g., 2,4-D, MCPA), benzoic acids (e.g., dicamba, chloramben), pyridines 

(e.g., picloram, clopyralid), and quinolinecarboxylic acids (e.g., quinclorac, quinmerac). Generally, 

auxinic herbicides are effective against broadleaf (dicotyledonous) plant species, allowing them to 

 

40 There are several systems of herbicide mode-of action classification. Among the most widely used are those of the Herbicide 

Resistance Action Committee (HRAC) and the Weed Science Society of America. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 68 of 946

often be used in production of narrow leaf (monocotyledonous) crops. Refer to Appendix A for 

details on dicamba herbicide.

Glufosinate Herbicide Use: Glufosinate was approved by the U.S. EPA for agricultural uses in 

1989 (U.S. EPA 2013b). Glufosinate is a non-selective foliar herbicide that is used for preplant and 

postemergence control of grass and broadleaf weeds. Glufosinate is formulated as a stand-alone 

herbicide product and marketed under the trade names Liberty®, IgniteTM, Ignite®280, RelyTM 200, 

and Rely®280. All products contain either 1.67 or 2.34 lbs per gallon of glufosinate-ammonium. 

Glufosinate (Rely®280 and Ignite®280) is used for postemergence weed control in canola, corn, 

cotton, and soybean varieties that are glufosinate-tolerant. Glufosinate may be used for weed control 

in non-glufosinate-tolerant cotton when applied with a hood sprayer in-crop. It may also be applied 

as a preplant burndown application in commercial varieties of canola, corn, cotton, soybean, or 

sugar beet. In addition, glufosinate (Rely®200 and Rely®280) may be used for postemergence weed 

control in apples, berries, grapes, tree nuts, and applied for potato vine desiccation. Glufosinate 

products can be tank mixed with other active ingredients depending on the treated crop. For 

example, IgniteTM can be tank mixed with metolachlor or fluometuron for in-crop applications in 

glufosinate-tolerant cotton. However, reduced weed control has been observed when glufosinate is 

tank mixed with glyphosate (Dotray, et al. 2011b; Reed, et al. 2011; Reed, et al. 2012). 

Glufosinate-treated acreage across all crops has steadily increased from 1.6 million acres in 1998 to 

7.0 million acres in 2011. Increased weed resistance is one factor responsible for the increased use 

of glufosinate (Roberson 2012). Glufosinate is currently labeled for in-crop application on 

glufosinate-tolerant cotton from emergence through early bloom growth stage at 0.402 to 0.530 lbs 

a.i. per acre, seasonal maximum of 1.59 lbs a.i. per acre (Bayer Crop Science 2007). The average 

application rate in cotton is 0.39 pounds of glufosinate per acre with an average of 1.5 applications 

per season. 

Herbicide Resistance: Herbicide resistance is “the inherited ability of a plant to survive and 

reproduce following exposure to a dose of herbicide normally lethal to the wild type” (WSSA 1998). 

In the mid-1950s, Harper (1957) theorized that annual, repeated use of a herbicide could potentially 

lead to shifts in weed species composition within a crop-weed community if other weed 

management methods are not utilized. Similarly, Bandeen et al. (1982) suggested that a normal 

variability in response to herbicides exists among plant species and tolerance can increase with 

repeated use of a herbicide in the absence of other weed management methods. To simplify, 

herbicide resistance in weeds is a result of natural selection. Plants of a given species are not 

identical, but are made up of “biotypes” with various genetic traits. The repeated use of a herbicide 

may potentially lead to the selection of weed biotypes resistant to that herbicide, particularly when 

the herbicide is not used as part of a diversified weed management program. Within a weed species, 

individuals may possess an inherent ability to withstand the effects of a particular herbicide. 

Repeated use of that herbicide in the absence of other weed control herbicides or practices has the 

potential to expose the weed population to a “selection pressure,” which may potentially lead to an 

increase in the number of surviving resistant individuals in the population (HRAC 2011). With 

repeated application of the same herbicide over time and no other appropriate herbicide or weed 

management practices, the resistant biotypes have the potential to become the dominant biotype in 

that weed community. As of April 2013, 400 herbicide-resistant weed biotypes have been reported 

to be resistant to 21 different herbicide modes-of-action worldwide (Heap 2013b). Glyphosateresistant weeds account for approximately 6% of the herbicide-resistant biotypes while weeds 

resistant to herbicides that inhibit acetolactate synthase (ALS) account for 32% of the herbicideresistant biotypes. Dicamba-resistant and glufosinate-resistant weeds account for <1% and 0.5% of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 69 of 946

resistant biotypes respectively (Heap 2012c; d; 2013b). See Appendix B for details of effects of 

weed resistance in agricultural systems. 

For as long as herbicide resistance has been a known phenomenon, public-sector weed scientists, 

private-sector weed scientists, and growers have been identifying methods to address the problem. 

For instance, when a farmer uses multiple weed control tools, resistant biotypes generally will not 

become the dominant biotype within a population (Gunsolus 2008). By contrast, there is a greater 

potential for weed resistance in areas where there is a sole reliance on a single herbicide used 

repeatedly over multiple crop generations for the management of a specific weed spectrum and 

where other appropriate weed management practices are not utilized.

On agricultural land which contains a weed biotype that is resistant to a particular herbicide, the 

grower must use alternate methods of weed control. Management practices that can be used to 

mitigate the potential for development of resistance include, among other things, herbicide mixtures, 

herbicide rotation, and crop rotation. The WSSA reports: “Weed scientists know that the best 

defense against weed resistance is to proactively use a combination of agronomic practices, including 

the judicious use of herbicides with alternative modes-of-action either concurrently or sequentially”

(WSSA 2010). Studies have demonstrated that using the same combination of herbicides with 

multiple modes of action and overlapping effectiveness over multiple seasons is an effective way to 

proactively manage weed resistance (Beckie and Reboud 2009; Neve et al. 2011). 

Due to the broad spectrum activity of glyphosate, it has been possible for growers to rely on 

glyphosate for weed management without utilizing other weed management practices such as crop 

rotation, cultivation, or use of multiple herbicide modes-of-action; these practices have resulted in 

the selection of certain glyphosate-resistant weed biotypes. 

Glyphosate-resistant weed biotypes that can be found in cotton fields in certain areas of the U.S.

may include broadleaf biotypes of Palmer amaranth, waterhemp, common ragweed, giant ragweed, 

marestail, spiny amaranth (Amaranthus spinosus), and grass biotypes of ryegress, Johnsongrass 

(Sorghum halapense) and goosegrass (Elusine indica) (Heap 2012e). As with other herbicide-resistant

weeds that have developed, the existence of herbicide-resistant weeds, including glyphosate-resistant

weed biotypes, over the past decade has required growers to adapt and implement diversified weed 

management strategies.

The occurrence of weed-resistant biotypes varies across the cotton growing regions, with more 

resistance issues observed more frequently in the Southeast and Midsouth cotton growing regions. 

Table II.B-19 summarizes known resistance among the major weed species present in the southern 

U.S. for each of the key herbicide groups and herbicide classes that are efficacious on broadleaf 

weeds (Heap 2013b). Amaranthus spp., in particular Palmer amaranth, are weeds that present 

challenges in the mid-south and southeastern U.S. Palmer amaranth is considered to be one of the 

hard-to-control of the Amaranthus spp. because of its rapid growth and prolific seed production. In 

addition, it has developed resistance to multiple herbicide classes (glycines, ALS, and dinitroanilines) 

(Culpepper et al. 2011; Heap 2013a). Managing herbicide-resistant Palmer amaranth has proven to 

be challenging due to the biology of this particular weed, including its dioecious nature (the male and 

female flowers occur on separate plants), which leads to greater genetic diversity in the plant 

population and increases the potential for spreading herbicide resistance (Sosnoskie, et al. 2011). 

Resistance to the ALS group of herbicides is present in most of the major broadleaf weed species 

commonly found in cotton. For Amaranthus spp. and Ambrosia spp., there is known resistance to at 
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least one member for several of the major herbicide chemistry classes. In an effort to manage 

glyphosate-resistant Palmer amaranth, certain non-glyphosate herbicides have been reported as 

being used in conditions and practices that have the potential to result in increased selection of 

resistant biotypes to those herbicides, thereby putting certain agricultural herbicides in some major 

herbicide classes at risk (Nichols, et al. 2010; Prostko 2011a; b) (Dr. Larry Steckel and Dr. Stanley 

Culpepper, personal communications, August 2012). While effective options for managing Ambrosia

spp., and Amaranthus spp., including Palmer amaranth and other key broadleaf weeds exist, there is a 

need for additional herbicide modes-of-action to mitigate potential future resistance of the key 

herbicides needed for weed management in cotton. In addition, there has been an increase in the 

detection of weed populations with multiple resistances (i.e., resistance to multiple herbicide modesof-action) in certain weed species, for example, Amaranthus spp. (Tranel et al. 2010). The emergence 

of these resistant biotypes demonstrates the continued need to utilize diversified weed management 

practices, including the need for additional herbicide modes-of-action that are effective in major 

crops. 

The relative occurrence of herbicide-resistant weeds varies between the different sub-groups of 

auxinic (phenoxy in Table II.B-19) herbicides. Considering that auxin herbicides have been widely 

used in agriculture for more than 60 years, weed resistance to this class is relatively low (29 species, 

to date, worldwide) and its development has been slow especially when compared to the speed of 

appearance of resistance to ALS inhibitors (107 species) or triazine-resistant populations (68 species) 

(Heap 2012d). The relatively low incidence of auxinic herbicide resistance is believed to be 

attributable to the fact that there are multiple target sites for these herbicides (Gressel and Segel 

1982; Morrison and Devine 1993).

Specific weed management recommendations by area or farm are often made by local experts versed 

in effective methods for both proactive and reactive resistance management. Since more than 

53.4% of cotton is repeatedly grown on the same land the use of multiple herbicide modes-of-action 

with overlapping effectiveness on the targeted weed spectrum is an important method 

recommended and employed for weed resistance management. Studies have shown that using the 

same combination of herbicides with multiple modes-of-action and overlapping effectiveness over 

multiple seasons can effectively manage resistance (Beckie and Reboud 2009). Monsanto and the 

weed scientist community recommend the use of multiple herbicide modes-of-action in herbicidetolerant cotton systems regardless of whether glyphosate-resistant or hard-to-control broadleaf 

weeds are present (University of Georgia 2012; University of Tennessee 2012). APHIS has 

deregulated multiple herbicide-tolerant cotton traits (Table II.B-20), and the use of diversified weed 

management systems with these traits helps ensure sustained profitable cotton production across the 

Cotton Belt. For growers using the herbicide-tolerant cotton systems, Monsanto and university 

extension weed scientists provide recommended control options for herbicide-resistant weeds41 

(Bond, et al. 2011; Culpepper, et al. 2013; Ferrell, et al. 2012; Jordan, et al. 2011; Monsanto 

Company 2012b; Norsworthy et al. 2012; Price et al. 2011; Prostko 2011b; University of Tennessee 

2012). These options include the use of residual and postemergence herbicides such as microtubule 

inhibitors (pendimethalin, trifluralin), PSII inhibitors (diuron, fluometuron, prometryn), PPO 

inhibitors (flumioxazin, fomesafen), long-chain fatty acid inhibitors (acetochlor, metolachlor), 

 

41 https://www.roundupreadyplus.com
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synthetic auxins (2,4-D, dicamba), and ALS inhibitors (pyrithiobac).42 These herbicides alone or in 

combinations, as well as traditional tillage methods, are and will continue to be used to control 

herbicide-resistant or hard-to-control broadleaf weeds. Refer to Appendix B for details on weed 

resistance.

 

42 Monsanto Technology Use Guide; www.weedresistancemanagement.com.
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Table II.B-19. Known Weed Resistance in the Southern U.S. in 20121 

Resistance 

(Group) 2 

ALS 

(Group 2)

PPO 

(Group 14) 

PSI 

(Group 22) 

PS II 

(Group 5) 

PS II 

(Group 7) 

Organoarsenicals 

(Group 

25) 

Microtubule 

Assembly 

Inhibitors 

(Group 3)

Glycine 

(Group 9) 

Phenoxy 

(Group 4) 

Chemistry Class 2 

sulfonylurea

diphenyl 

ether

N-phenyl 

thalimide bipyridiliums triazine ureas 

organoarsenicals dinitroaniline glycine phenoxy benzoic 

acid 

Cotton Herbicide 

Examples

Trifloxysulfuron Fomesafen Flumioxazin Paraquat Prometryn Diuron 

Fluometuron MSMA Trifluralin Glyphosate 2,4 D Dicamba

Most Common Broadleaf Weeds in Southeast / Midsouth ( # of states listing as a top weed) 

morningglory

(11) 

Ipomoea spp. 

prickly sida (9) 

Sida spinosa

pigweed spp. (6) 

Amaranthus spp.3 

X X X X X

Palmer 

amaranth (4) 

Amaranthus 

palmeri

X X X X

Florida Pusley

(4) 

Richardia scabra 

sicklepod (4) 

Senna obtusifolia 

cocklebur (3) 

Xanthium 

strumarium

X X

horseweed 

(marestail) (3) 

Conyza canadensis

X X X X X

Ragweed spp.

(2) 

Ambrosia spp. 

X X X X

Florida 

Beggarweed (2) 

Desmodium 

tortuosum

1 Source: (Heap 2012e), www.weedscience.org

2 Cross resistance is possible within a resistance group and/or chemistry class.

3 Includes redroot pigweed, smooth pigweed and common waterhemp.

Note: Blank boxes indicate no resistant biotypes for weed species/ herbicide combination in Southern U.S.
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Table II.B-20. Deregulated Biotechnology-derived Cotton Products1

Phenotype Event Institution

Deregulation 

Effective Date 

Glufosinate tolerant, 

Lepidopteran resistant T303-3XGHB119 Bayer CropScience August, 2012

Glufosinate tolerant, 

Lepidopteran resistant T304-40XGHB119 Bayer CropScience October, 2011

Lepidopteran resistant COT 67B Syngenta September, 2011

Glyphosate tolerant GHB614 Bayer CropScience May, 2009

Glyphosate tolerant MON 88913 Monsanto December, 2004

Lepidopteran resistant COT 102 Syngenta July, 2005

Lepidopteran resistant 281-24-236 Mycogen/Dow July, 2004

Lepidopteran resistant 3006-210-23 Mycogen/Dow July, 2004

Phosphinothricin tolerant2 LLCotton25 Aventis March, 2003

Lepidopteran resistant Cotton 15985 Monsanto November, 2002

Bromoxynil tolerant and 

lepidopteran resistant 31807 and 31808 Calgene April, 1997

Sulfonylurea tolerant 19-51a DuPont January, 1996

Glyphosate tolerant 1445, 1698 Monsanto July, 1995

Lepidopteran resistant 531, 757, 1076 Monsanto June, 1995

Bromoxynil tolerant BXN Calgene February, 1994

1

(USDA-APHIS 2013b).

2

 Glufosinate tolerant.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 74 of 946

II.B.2.e. Organic Production Practices

National Organic Program and Organic Cotton Farming: In the U.S., only products 

produced using specific methods and certified under the USDA’s Agricultural Marketing 

Service (AMS) National Organic Program (NOP) definition of organic farming can be 

marketed and labeled as “organic” (USDA-AMS 2010). Organic certification is a process-based 

certification, not a certification of the end product; the certification process specifies and audits 

the methods and procedures by which the product is produced.

In accordance with NOP, an accredited organic certifying agent conducts an annual review of 

the certified operation’s organic system plan and makes on-site inspections of the certified 

operation and its records. Organic growers must maintain records to show that production and 

handling procedures comply with USDA organic standards.

The NOP regulations preclude the use of excluded methods. The NOP provides the following 

guidance under 7 CFR § 205.105:

“...to be sold or labeled as ‘100 percent organic’, ‘organic’ or 

‘made with organic (specified ingredients or group(s)),’ the 

product must be produced and handled without the use of:

(a) Synthetic substances and ingredients,...

(e) Excluded methods,...”

Synthetic Substances are defined in 7 CFR § 205.2 as:

“A substance that is formulated or manufactured by a chemical 

process or by a process that chemically changes a substance 

extracted from naturally occurring plant, animal, or mineral 

sources, except that such term shall not apply to substances 

created by naturally occurring biological processes.” This 

includes synthetic herbicides, insecticides, and fertilizers.

Finally, Excluded methods are defined as:

“A variety of methods used to genetically modify organisms or 

influence their growth and development by means that are not 

possible under natural conditions or processes and are not 

considered compatible with organic production...”

Organic farming operations, as described by the NOP, are required to have distinct, defined 

boundaries and buffer zones to prevent unintended contact with prohibited substances and 

excluded methods from adjoining land that is not under organic management. Organic 

production operations must also develop and maintain an organic production system plan 

approved by their accredited certifying agent. This plan enables the production operation to 

achieve and document compliance with the National Organic Standards, including the 

avoidance of use of prohibited substances and excluded methods (USDA-AMS 2010).
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Most EPA-registered pesticides are prohibited in organic production; however, there is the 

potential for inadvertent or indirect contact from neighboring conventional farms or shared 

handling facilities. As long as the operator has not directly applied prohibited pesticides and has 

documented efforts to minimize exposure to them, the USDA organic regulations allow for 

residues of prohibited pesticides at or below 5 percent of the EPA tolerance. (USDA-AMS 

2012b). 

Although the National Organic Standards preclude the use of excluded methods, they do not 

require testing of inputs or products for the presence of excluded methods. The presence of a 

detectable residue of a product of excluded methods alone does not necessarily constitute a 

violation of the National Organic Standards (USDA-AMS 2011). The current NOP regulations 

do not specify an acceptable threshold level for the adventitious presence of GE materials in an 

organic-labeled product. The unintentional presence of the products of excluded methods will 

not affect the status of an organic product or operation when the operation has not used 

excluded methods and has taken reasonable steps to avoid contact with the products of 

excluded methods as detailed in their approved organic system plan (USDA-AMS 2011).

Organic cotton producers use production practices designed to prevent commingling of their 

value-added crop with neighboring crops treated with herbicides and other pesticides or that 

may be using plant varieties produced by excluded methods. In addition, steps are taken to 

avoid spray drift from neighboring fields. These well-established practices include isolation 

zones, use of buffer rows surrounding the organic crop, adjusted planting dates, and varietal 

selection (Kuepper 2006). 

The efficacy of management practices utilized to avoid pollen movement from a GE crop to 

organic cotton production operations is facilitated by the nature of cotton pollination. Cotton 

is a self-pollinated species and exhibits a low level of outcrossing (Section II.D.2.c). 

U.S. Organic Cotton Production: The USDA census of organic agriculture reported organic 

cotton farming on 30 farms in the U.S. in 2008, two in Arizona, three in New Mexico, four in 

California, and 21 in Texas (USDA-NASS 2008a). Texas (66%) and New Mexico (20%) 

together accounted for approximately 86% of the production. Based on USDA-ERS data, 

between 1997 and 2008, organic cotton acreage ranged from 9,213 acres in 2004 to 15,377 acres 

in 2008 (USDA-ERS 2008). In 2008 about 0.16% of the total 9.41 million acres of cotton was 

produced organically (USDA-ERS 2008). In recent years, small and sporadic acreages of 

organic cotton production have been cultivated in other states, including Missouri, Illinois, 

Kansas, Tennessee, and Colorado (USDA-ERS 2010c). Based upon recent trend information, 

the presence of GE cotton varieties on the market has not affected the ability of organic 

production systems to maintain their market share. Between 2000 and 2008, although 11 GE 

cotton events were no longer subject to regulation under the Plant Protection Act and 7 CFR 

Part 340, the acreage of organic cotton production remained at approximately 15,000 acres 

(USDA-APHIS 2013a; USDA-ERS 2008).

The South Plains area of Texas is one of the primary regions for organic cotton production 

(TOCMC 2011b). Features that make the South Plains well-suited for organic cotton 

production include cold enough winter temperatures to limit insect pressure and to provide a 

hard freeze to defoliate the cotton plants prior to harvesting, and a sunny climate and quick-
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drying soils to facilitate timely mechanical weed control. As many of these farmers do not 

irrigate, yields are heavily dependent upon rainfall (TOCMC 2011b).

Organic cotton growing practices include the use of natural defoliants; beneficial insects for 

pest control; compost, manure, and crop rotations for fertilizers; and hand-weeding, mechanical 

cultivation, cover crops and mulching for weed control. The same gins and spinning mills used 

for non-organic cotton are also used for organic cotton; however, they must be shut down and

cleaned before processing the organic cotton, which adds to production costs (TOCMC 2011a).

Most U.S. organic cotton growers sell their cotton products through a marketing cooperative, 

the largest of which is the TOCMC, with approximately 30 members (OTA 2012; TOCMC 

2011b). Cottonseed is marketed to organic dairies for feed (TOCMC 2011b). According to a 

survey conducted by OTA, organic cotton growers’ biggest barriers to planting more organic 

cotton are finding a market willing to pay the added costs of organic products, production 

challenges such as weed and insect control, and labor costs. “Growers also cited competition 

from international organic cotton producers, as well as the cost of transition to organic.” (OTA 

2010). 

II.B.2.f. Other Specialty Market Production

Production systems designed prior to the introduction of GE-derived cotton have allowed for 

production of cotton to meet varied customer demands. In addition to the market segments 

that produce organic cotton and non-GE cotton, distinct identity-preserved specialty cotton 

has also been grown and successfully marketed for many years.

Specialty cottons cultivated in the U.S. include organic cotton (discussed above), non-GE 

cotton, and naturally colored cotton (Lee 2007). Naturally colored cotton acreage is grown on 

between 5,000 and 7,000 acres, according to 1995 estimates (Lee 2007).

Specialty crop growers employ practices and standards for seed production, cultivation, and 

product handling and processing to ensure that their products are not pollinated by or 

commingled with other cotton crops (which includes GE crops) (Bradford 2006). These 

management practices include maintaining isolation distances to prevent pollen movement 

from other cotton sources, planting border or barrier rows to intercept pollen, and employing 

natural barriers to pollen (Bradford 2006; Kuepper 2006; Wozniak and Martinez 2011). These 

management practices allow the grower to meet standards for the production of specialty crop 

seed, maintain genetic purity, and protect the genetic diversity of cotton (Bradford 2006).

II.B.2.g. Seed Production Practices

On an annual basis, the supply of certified seed of all varieties of cotton combined must be able 

to plant over 10 million acres in the U.S. alone (NCPA 2013; USDA-NASS 2010a). This 

requires between 60,000 and 70,000 short tons of planting seed (NCPA 2011).

The majority of the cotton seed crop is produced in Texas, with significant quantities produced 

in Arizona, Arkansas, California, and Mississippi (McDonald and Copeland 1997). Seed 

companies minimize the risk of crop loss due to weather events by producing seed in multiple 

regions.
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Seed quality (including genetic purity, vigor, and presence of weed seed, seed-borne diseases, 

and inert materials such as dirt) is a major factor in crop yields. If natural variability in seed 

production is not carefully controlled, the value of a new variety or cultivar may be lost 

(Hartmann et al. 1975). Genetic purity in commercial seed production is generally regulated 

through a system of seed certification which is intended to ensure that the desired traits in the 

seed are maintained throughout all stages in cultivation (Hartmann et al. 1975).

States have developed seed laws and certification agencies to ensure that purchasers who 

received certified seed can be assured that the seed meets established seed quality standards 

(Bradford 2006). The U.S. Federal Seed Act of 1939 recognizes seed certification and official 

certifying agencies. Implementing regulations further recognize land history, field isolation, and 

varietal purity standards for Foundation, Registered, and Certified seed.

In a seed certification program, classes of seed are identified to designate the seed generation 

from the original breeder source (Hartmann et al. 1975). Foundation seed, Registered seed, and 

Certified seed production is controlled by public or private seed certification programs 

(AOSCA 2009a). The original seed breeder seed stock is controlled by the developer of the 

variety (Adam 2005; Hartmann et al. 1975). The breeder stock is used to produce Foundation 

seed stock (Adam 2005). The institution associated with the breeder controls the production of 

Foundation seed stock. Foundation seed stock, in turn, is used to produce Registered seed for 

distribution to licensees, such as seed companies (Adam 2005). Registered seed is used by seed 

companies to produce large quantities of Certified seed (Adam 2005; Hartmann et al. 1975). 

The Certified (or Select) seed is then sold to growers through commercial channels (Adam 

2005; Hartmann et al. 1975). 

Seed certification cultivation practices commonly include recommendations for minimum 

isolation distances between various seed lines and planting border or barrier rows to prevent 

pollen movement (Hartmann et al. 1975; Wozniak and Martinez 2011). The isolation distance 

for Foundation, Registered, and Certified seeds, as dictated by the USDA Agricultural 

Marketing Service’s (AMS) Federal Seed Act, is 1,320, 1,320, and 660 feet, respectively 

(7 CFR Part 201.76). During the growing season, seed certification agencies will monitor the 

fields for off-types, other crops, weeds, and disease (Wozniak and Martinez 2011). These 

certifying agencies also establish seed handling standards to reduce the likelihood of seed source 

mixing during production stages, including planting, harvesting, transporting, storage, cleaning, 

and ginning (Wozniak and Martinez 2011). Further discussion of cross-pollination, gene 

transfer, and weediness is presented in Subsection II.D.2.c. 

II.C. PHYSICAL ENVIRONMENT

II.C.1. Land Use and Soil Quality

The cumulative land area in the U.S. planted to principal crops, which include corn, sorghum, 

oats, barley, winter wheat, rye, durum, spring wheat, rice, soybean, peanuts, sunflower, cotton, 

dry edible beans, potatoes, canola, proso millet, and sugar beets, has remained relatively 

constant over the past 27 years. From 1982 to 1995, the average yearly acreage of principal 

crops was 323 million. This average is essentially unchanged at 326 million acres since the 

introduction of biotechnology-derived crops in 1996 (USDA-NASS 1984; 1990; 1992; 1995; 

1998; 2000; 2003; 2006; 2009a). Thus, there is no indication that the introduction and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 78 of 946

widespread adoption of biotechnology-derived crops in general has resulted in a significant 

change to the total U.S. acreage devoted to agricultural production. 

Soil consists of solids (minerals and organic matter), liquids, and gases. This body of inorganic 

and organic matter is home to a wide variety of fungi, bacteria, and arthropods, as well as the 

growth medium for terrestrial plant life (USDA-NRCS 2003). Soil is characterized by its layers 

that can be distinguished from the initial parent material due to additions, losses, transfers, and 

transformations of energy and matter. It is further distinguished by its ability to support rooted 

plants in a natural environment. Soil plays a key role in determining the capacity of a site for 

biomass vigor and production in terms of physical support, air, water, temperature moderation, 

protection from toxins, and nutrient availability. Soils also determine a site’s susceptibility to 

erosion by wind and water, and flood attenuation capacity.

Cultivation and tillage practices can directly impact soil, including its physical and biological 

properties. Conventional tillage traditionally requires that the producer remove all plant 

residues and weeds from the soil surface prior to planting, and then continue to cultivate the 

soil while the crop is growing in order to control late emerging weeds (Cotton Inc. 2010a). 

This practice results in soil loss due to wind and water erosion. Microbial populations and

associated biochemical processes are critical to maintaining soil health and quality. 

Conservation practices developed to reduce field tillage have reduced the corresponding soil 

loss (USDA-NRCS 2005). 

Conservation practices cause increases in soil organic matter that help bind soil nutrients and 

significantly reduce the loss of cropland soil from runoff, erosion, and leaching over time 

(Leep, et al. 2003; USDA-NRCS 2005). Total soil loss on highly erodible croplands and nonhighly erodible croplands decreased from 3.06 billion tons per year in 1982 to 1.7 billion tons 

per year in 2007, or by 43% (USDA-NRCS 2010). This decrease in soil erosion accompanies a 

corresponding decrease in non-point source pollution of surface water by fertilizer and 

pesticides (Reicosky 2008). Soil tillage can also affect water resources and air quality.

The introduction of glyphosate-tolerant crops accelerated the growth of conservation tillage in 

the U.S., in large part because of the broad spectrum postemergence control offered by 

glyphosate (Price et al. 2011). 

By definition, conservation tillage leaves at least 30% of the soil covered by crop residue (Peet 

2001). The new crop is planted into the plant residue or in narrow strips of tilled soil. This is 

in comparison to conventional tillage where the seedbed is prepared through plowing (to turn 

the soil surface over), disking (to reduce the size of soil clods created by plowing), and 

harrowing (to reduce the size of clods left by disking) (Peet 2001). Benefits of reduced tillage 

practices include maintenance of soil organic matter and beneficial insects, increased soil waterholding capacity, less soil and nutrient loss from the field, reduced soil compaction, and less 

time and labor required to prepare the field for planting (Peet 2001). Weed control in 

conservation tillage crops is primarily through the use of herbicides (ACES 1996). Winter and 

cover crops are also utilized in conservation tillage for the purpose of suppressing weeds 

(Alabama Cooperative Extension System, 1996). 

Although soil erosion rates are dependent on numerous local conditions such as soil texture 

and crop, a comparison of 39 studies contrasting conventional and no-till practices illustrates 
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that, on average, no-till practices reduce erosion 488 times over conventional tillage 

(Montgomery 2007). This reduction is enough to bring soil production more in line with losses 

from erosion. From 1982 through 2003, erosion on U.S. cropland dropped from 3.1 billion 

tons per year to 1.7 billion tons per year (USDA-NRCS 2006a). This can partially be attributed 

to the increased effectiveness of weed control through the use of herbicides and the 

corresponding reduction in the need for mechanical weed control (Carpenter, et al. 2002). 

Conservation tillage also minimizes soil compaction due to the reduced number of tillage trips.

In some regions, conservation tillage is required. Farmers producing crops on highly erodible 

land are required by law to maintain a soil conservation plan approved by the USDA National 

Resources Conservation Service (NRCS) (USDA-ERS 2010a). These soil conservation plans 

are prepared by the grower pursuant to the 1985 Food Security Act Conservation Compliance 

and Sodbuster programs to minimize soil erosion (USDA-ERS 2010a).

While conservation tillage does have several benefits for soil health, some management 

concerns are associated with its use. Under no-till practices, soil compaction may become a 

problem as tillage is useful for breaking up compacted areas (USDA-NRCS 1996). Likewise, 

not all soils (such as wet and heavy clay soils) are suited for no-till. Also, no-till practices may 

lead to increased pest occurrences that conventional tillage is better suited to managing (NRC 

2010). Other methods to improve soil quality include careful management of fertilizers and 

pesticides; use of cover crops to increase plant diversity and limit the time soil is exposed to 

wind and rain; and, increased landscape diversity with buffer strips, contour strips, wind breaks, 

crop rotations, and varying tillage practices (USDA-NRCS 2006b).

Soybeans

In 2012, soybean was grown as a commercial crop on over 77 million acres in at least 31 states 

in the U.S. (USDA-NASS 2013b). Soybean acreage in the past five years has been relatively 

stable, varying from 75.0 million to 77.5 million acres with a 10-year average of 74.3 million 

acres. Soybean fields are typically highly managed and are dedicated to crop production for 

many years. However, small fluctuations in soybean acreage do occur because of 

environmental, agronomic and economic factors, as well as government programs such as the 

conservation reserve program (CRP). 

Approximately 93% of the soybean acreage in the U.S. is planted with GE herbicide-tolerant 

soybean varieties (USDA-ERS 2012b), and the Glyphosate-tolerant soybean system has 

become the standard weed control program in U.S. soybean production. 

Soybean is cultivated across a wide variety of soils in the U.S. but grows best in a loose, welldrained loam (NSRL 2013). Cultivation and tillage practices can directly impact the attributes 

of soil, including its physical and biological properties. Microbial populations and associated 

biochemical processes are critical to maintaining soil health and quality. Additionally, 

maintaining soil pH in the range of 6.0 to 7.0 will enhance the availability of inherent and 

fertilizer nutrients, reduce the availability of toxic elements – particularly aluminum and 

manganese – and enhance microbial activity (Hoeft, et al. 2000b; c; Hoeft et al. 2000a; Hoeft, et 

al. 2000a; Hoeft et al. 2000b). The increased microbial activity that is associated with the 

optimum pH level results in oxidation of organic matter and increased release of nutrients from 

the organic matter. Soybeans need a variety of macronutrients, such as nitrogen, phosphorus, 
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potassium, calcium, magnesium, and sulfur, at various levels (NSRL 2013). They also require 

smaller amounts of micronutrients such as iron, zinc, copper, boron, manganese, molybdenum, 

cobalt, and chlorine. These micronutrients may be deficient in poor, weathered soils, sandy 

soils, alkaline soils, or soils excessively high in organic matter.

In 2008, approximately 30.1 million acres (46.3%) of soybean were planted in a no-till system 

(CTIC 2008). In 2011, approximately 65% of U.S. soybean acres used some form of 

conservation tillage (ASA 2011; CTIC 2008). 

Cotton

Cotton is cultivated in a wide variety of soils, but develops best in deep, arable soils with good 

drainage, high organic content, and a high moisture-retention capacity (OECD 2008). 

Irrigation allows cultivation in poor-quality soils with necessary nutrients provided in the 

irrigation water (OECD 2008).

Tillage is the aspect of cotton farming that has the greatest potential impact on soil. 

Glyphosate-tolerant cotton has facilitated the growth of conservation tillage systems in cotton 

production (Baldwin and Baldwin 2002; Carpenter and Gianessi 2001). As of 2008, 

conservation tillage systems are used on approximately 21% of the U.S. cotton acres (CTIC 

2008). Wheat and rye are commonly employed as cover crops because of their ease in killing

prior to cotton planting. The use of herbicide-resistant cotton has allowed cotton growers to 

more readily adopt soil conservation practices because it provides an economical, effective 

means of controlling weeds in post-plant cotton (ACES 1996; McClelland et al. 2000)

II.C.2. Water Resources

The principal law governing pollution of the nation’s water resources is the Federal Water 

Pollution Control Act of 1972, better known as the Clean Water Act (CWA). The Act utilizes 

water quality standards, permitting requirements, and monitoring to protect water quality. The 

EPA sets the standards for water pollution abatement for all waters of the U.S. under the 

programs contained in the CWA, but, in most cases, gives qualified states the authority to issue 

and enforce permits. Drinking water is protected under the Safe Drinking Water Act of 1974 

(Public Law 93-523, 42 U.S.C. 300 et seq.). 

Surface water in rivers, streams, creeks, lakes, and reservoirs supports everyday life through the 

provision of water for drinking and other public uses, irrigation, and industry. Surface runoff 

from rain, snowmelt, or irrigation water can affect surface water quality by depositing sediment, 

minerals, or contaminants into surface water bodies. Surface runoff is influenced by 

meteorological factors such as rainfall intensity and duration, and physical factors such as 

vegetation, soil type, and topography.

Groundwater is the water that flows underground and is stored in natural geologic formations 

called aquifers. It sustains ecosystems by releasing a constant supply of water into wetlands and 

contributes a sizeable amount of flow to permanent streams and rivers. Based on 2005 data, 

the largest use of groundwater in the U.S. is irrigation, representing approximately 67.2% of all 

the groundwater pumped each day (McCray 2009). Approximately 47% of the U.S. population 

depends on groundwater for its drinking water supply. The EPA defines a sole source aquifer 
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(SSA) as an aquifer that supplies at least 50% of the drinking water consumed in the area 

overlying the aquifer. An SSA designation is one tool to protect drinking water supplies in 

areas where there are few or no alternative sources to the groundwater resource. There are 77 

designated SSAs in the U.S. and its territories (U.S. EPA 2011a). 

Unlike a point source, which is a “discernible, confined and discrete conveyance”, nonpoint 

source pollution (NSP) comes from many diffuse sources. Rainfall or snowmelt moving over 

the ground, also known as runoff, picks up and carries away natural and human-made 

pollutants, creating NSP. The pollutants may eventually be transported by runoff into lakes, 

rivers, wetlands, coastal waters and ground waters. Agricultural NPS pollution includes 

agricultural sediments transported by erosion that may also include pesticides, fertilizers, and 

sometimes fuel and pathogens. Cotton and soybean production may impact groundwater due 

to movement of pesticides and fertilizers vertically through soil. Surface water may also be 

impacted from production by runoff from fields that carries soil particles, nutrients, and 

herbicides or other pesticides to streams, rivers, lakes, wetlands and other water bodies. 

Pesticides are a relatively minor contributor to impairment of surface water in the U.S., 

according to an analysis of states’ water quality reports to EPA, which EPA makes available 

through its National Assessment Database (U.S. EPA 2008a). As discussed below, based on 

existing data, the soil component of runoff is a much more important contributor to surface 

water impacts than is the pesticide component. 

Dicamba has been widely used in agriculture over the last four decades with dicamba’s peak use 

occurring in 1994 (see Appendix A of this Environmental Report for more detail). In the 

dicamba Reregistration Eligibility Decision (RED) document, EPA considered potential risks 

associated with dicamba use, and its degradate DCSA when appropriate, to surface or ground 

water using screening level (high-end exposure) models to estimate environmental 

concentrations. The EPA then compared these exposure estimates to appropriate endpoints 

from mammalian and aquatic animal and plant ecotoxicity studies to determine potential 

impacts on human health and the environment. The EPA used the models PRZM/EXAMS 

and SCIGROW to estimate levels of dicamba in surface and ground water, respectively, using 

the physical, chemical, and environmental fate properties, and subsequently concluded that all 

uses of dicamba, including high-end use patterns, were eligible for continued registration (see 

Appendix C of this Environmental Report for more detail).

While pesticides are relatively minor contributors to surface water impairment, existing data 

indicates that soil runoff is a more important contributor to surface water impacts. Tillage 

causes widespread soil disturbance; increased tillage therefore likely causes increased erosion, 

topsoil loss, sedimentation and turbidity. EPA has identified sedimentation and turbidity as 

two of the top ten causes of surface water impairment in general and sedimentation/siltation as 

a leading cause of impairment to rivers and streams in particular (U.S. EPA 2007a; 2009b). 

Tillage causes widespread soil disturbance. Vegetative residues protect the soil surface from the 

impact of raindrops and slow the movement of water, reducing its load-carrying potential. 

Slower moving water leads to water absorption and less runoff. Runoff may carry soil particles, 

nutrients and pesticides away from fields to water bodies. Even as little as 30% residue cover 

typically reduces soil erosion rates by >50 % compared to bare ground (University of Missouri 

1993). Typical soil loss from a field with a 93% residue cover may be only 2% of the loss from 
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a field with 0% residue cover (Hill and Mannering 1995). Thus, erosion of topsoil, nutrient 

loss, and the resulting sedimentation, turbidity, and transport of nutrients to streams are likely 

to increase with increased tillage. Sediments and nutrients, primarily from agricultural crops, are 

the second and third leading causes of impairment in U.S. streams and rivers (pathogens are the 

leading cause), accounting for 21% and 20% of the miles of impaired streams and rivers, 

respectively. By comparison, pesticides account for 3% of miles of impaired streams and rivers, 

and these are primarily persistent pesticides such as DDT, chlordane, and DDE, which are no 

longer used in the U.S. (U.S. EPA 2012b; 2013c). EPA has projected conservation tillage to be 

“the major soil protection method and candidate best management practice for improving 

surface water quality” (U.S. EPA 2002). EPA identifies conservation tillage as the first of its 

CORE4 agricultural management practices for water quality protection (U.S. EPA 2013d). 

Growth of conservation tillage in the U.S. was greatly accelerated with the introduction of 

glyphosate-tolerant crops, in large part because of the broad spectrum postemergence control 

offered by glyphosate (Price et al. 2011). By 2008 conservation tillage (no-till, reduced till and 

other conservation tillage methods) was employed on approximately 63% of the crop acres, 

compared to 48% in 1994 prior to the introduction of herbicide-tolerant crops (CTIC 2008). 

As noted above, conservation tillage systems are used on approximately 21% of U.S. cotton 

acres (CTIC 2008). 

Soybeans

In regions of the U.S. that experience low amounts of rainfall during the growing season or 

during drought, soybean yields benefit from proper irrigation. Soybeans require approximately 

20-25 inches of water during the growing season to produce a relatively high yield of 40-50 

bushels per acre (University of Arkansas 2006). In 2006 and 2008, approximately 9% of the 

planted acres of soybeans in the U.S. were irrigated (USDA-ERS 2011b; USDA-NASS 2008b; 

2010c). A majority (approximately 73%) of irrigated soybean farms occur in the Missouri and 

Lower Mississippi Water Resource Regions, with soybean farms in the states of Nebraska, 

Arkansas, Mississippi, Missouri, and Kansas accounting for 85% of all irrigated acres (USDANASS 2008b). In 2006, approximately 8.4 inches of water per irrigated acre was used, 

producing an average of over 51 bushels per irrigated acre (USDA-ERS 2011b). This yield was 

approximately 19.8% higher than the national average (42.9 bushels per acre) for that year 

(USDA-NASS 2010c). The soils and climate in the Midwestern, Eastern and portions of the 

Great Plains regions of the U.S. provide sufficient water under normal climatic conditions to 

produce a soybean crop. 

Pesticides accounted for less than one percent of reported causes of surface water impairment 

in all but four of the 17 leading U.S. soybean-producing states. In those four states, pesticides 

accounted for two to eight percent of reported causes of impairment. Of the pesticides that 

were reported as contributing to impairment among the 17 leading soybean-producing states, 

almost all are highly persistent chemicals that are no longer registered for use in the U.S. (U.S. 

EPA 2008a). Dicamba is not included on this list. 

Cotton

Cotton has been developed as a drought-tolerant crop. Cotton’s global water footprint 

represents about 2.6% of the world’s water use and is lower than soybeans, maize, wheat, and 

rice (Cotton Inc. 2010b). Cotton production water use varies according to the growing 
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environment (Cotton Inc. 2010b). Successful cultivation of dryland (non-irrigated) cotton 

requires at least 500 millimeters (mm) (40 inches) of rainfall during the growing season (OECD 

2008). Cotton cultivated in the southwestern region of the U.S., including west Texas, southern 

New Mexico, southern Arizona, and southern California, requires irrigation (USDA-APHIS 

2010a). Where irrigation water is needed (approximately 35% of the U.S. cotton grown), cotton 

yields are also much higher (Cotton Inc. 2010b). The desert southwest requires a maximum of 

40 inches of irrigation per year, although the humid southeast may only require about 18 inches 

of irrigation per year (Cotton Inc. 2010b). Carefully timing the application of irrigation water 

optimizes the plant’s vegetative growth, flowering, and boll production (OECD 2008). The lack 

of affordable water has been noted as one factor in the reduction of acres of cotton grown in 

California, Arizona, and New Mexico in the past decade (Cotton Inc. 2010b). In these areas, 

cotton has been displaced by higher value crops and land uses (Cotton Inc. 2010b).

II.C.3. Air Quality 

The Clean Air Act (CAA) requires the attainment and maintenance of National Ambient Air 

Quality Standards (NAAQS) in all areas of the U.S. The NAAQS, developed by the EPA to 

protect public health, establish limits for six criteria pollutants: ozone (O3), nitrogen dioxide 

(NO2), carbon monoxide (CO), sulfur dioxide (SO2), lead (Pb), and inhalable particulates 

(coarse particulate matter [PM] greater than 2.5 micrometers and less than 10 micrometers in 

diameter [PM10] and fine particles less than 2.5 micrometers in diameter [PM2.5]). The CAA 

requires states to achieve and maintain the NAAQS within their jurisdiction. Each state may 

adopt requirements stricter than those of the national standard and each is also required by 

EPA to prepare a State Implementation Plan (SIP) containing strategies to achieve and 

maintain the national standard of air quality within the state. Areas that violate air quality 

standards are designated as non-attainment areas for the criteria pollutant(s), whereas areas that 

comply with air quality standards are designated as attainment areas. 

Primary sources of emissions associated with crop production include vehicle exhaust from 

motorized equipment such as tractors and irrigation equipment, suspended soil particulates 

from tillage and wind induced erosion, smoke from burning of fields, drift from sprayed 

herbicides and other pesticides, and nitrous oxide emissions from the use of nitrogen fertilizer 

(Aneja, et al. 2009; Hoeft et al. 2000a; b; U.S. EPA 2011c; USDA-NRCS 2006a). 

Volatilization of fertilizers, herbicides and other pesticides from soil and plant surfaces also 

introduces certain chemicals to the air (Vogel, et al. 2008). A substance is volatile if it is likely 

to vaporize at atmospheric pressure. The USDA Agricultural Research Service (ARS) is 

conducting a long-term study to identify factors that affect pesticide levels in the Chesapeake 

Bay region airshed (USDA-ARS 2011). This study has determined volatilization is highly 

dependent upon exposure of disturbed unconsolidated soils and variability in measured 

compound levels is correlated with temperature and wind conditions. Another ARS study of 

volatilization of certain herbicides after application to fields has found moisture in dew and 

soils in higher temperature regimes significantly increases volatilization rates (USDA-ARS 

2011). For example, low-volatility forumations can reduce volatility and offsite movement. 

The DGA salt formulation of dicamba, which is one low-volatility formulation, has been

proposed for use on DT soybean and DGT cotton. For example, side-by-side field 

experiments have indicated that a formulation of the diglycolamine (DGA) salt of dicamba 

volatilized significantly less than a similar formulation of the DMA salt form (Egan and 
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Mortensen 2012). In the publication, the authors state, “Our data demonstrate that the 

diglycolamine formulation has a dramatic effect on reducing dicamba vapor drift. Estimates of 

total g acid equivalent vapor drift outside of the treated area were reduced 94% relative to the 

dimethylamine formulation, and the dose-distance curves indicate that predicted mean 

exposures drop close to zero only short distances away from the treated area.” Measured air 

concentrations when using the DGA salt, for example, were 30- to 50-fold lower than those in 

the potassium and DMA salt laboratory studies EFED evaluated, even though the application 

rate was twice that of DMA (Mueller 2010). See Appendix D for additional details.

Pesticide spraying may impact air quality from drift. EPA defines drift as “the movement of 

pesticide through air at the time of application or soon thereafter, to any site other than that 

intended for application” (U.S. EPA 2000). Factors affecting drift include application 

equipment and method, weather conditions, topography, and the type of crop being sprayed 

(U.S. EPA 2000). EPA’s Office of Pesticide Programs (OPP), which regulates pesticides in the 

U.S., encourages pesticide applicators to use all feasible means available to them to minimize 

drift. The Agency has introduced several initiatives to help address and prevent the problems 

associated with drift. Currently, EPA is evaluating new regulations for pesticide drift labeling 

and the identification of best management practices to control such drift (U.S. EPA 2009e), as 

well as identifying scientific issues surrounding field volatility of conventional pesticides (U.S. 

EPA 2010b). Additionally, OPP and EPA’s Office of Research and Development are 

developing a new voluntary program, the Drift Reduction Technology (DRT) Program, which 

encourages the development, marketing and use of application technologies verified to 

significantly reduce spray drift (U.S. EPA 2009e). 

Depending upon the herbicide being used, factors for managing the potential for spray drift 

include the selectivity and sensitivity of the herbicide, local weather conditions at the time of 

application (wind, temperature, humidity, inversion potential), droplet size distribution, 

application volume, boom height (height of the application equipment above the crop canopy), 

sprayer speed, and distance from the edge of the application area (Felsot, et al. 2010; SDTF 

1997). The minimization of droplets less than 150 microns is important in reducing any 

potential for spray drift. Droplet size can be increased by requiring the use of certain nozzle 

types, increasing volume per minute spray rates, and by specifying an application volume per 

acre rate of at least 10 gallons. (SDTF 1997; TeeJet Technologies 2011). Arvidsson et al. (2011)

investigated meteorological and technical factors affecting total spray drift and determined that 

boom height and wind speed were the primary factors affecting the potential for spray drift 

among those tested, followed by air temperature, driving speed and vapor pressure deficit. 

Arvidsson et al. (2011) demonstrated that drift increased with driving speed. This increase was 

attributed to either air flows associated with the forward movement of the sprayer or to 

increased vertical boom movement. Aerial application of pesticides may cause air quality 

impacts from drift and diffusion; however, aerial applications would not be permissible under 

Monsanto’s proposed dicamba label amendment application—currently pending before EPA—

for both DT soybean or DGT cotton, so there will be no issues with aerial application of 

pesticides potentially causing air quality impacts from drift and diffusion. 

Soybeans

The majority of soybean grown in the U.S. is rotated with corn on a two-year rotation. Soybean 

fields typically are tilled and the new crop rotation planted in the following year. Use of 
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herbicide-tolerant soybeans has facilitated conservation tillage and/or no-till soybean 

production, as it diminishes the need to till for weed control. Longer intervals between rotating 

crops and minimized earth disturbance from decreased tillage reduce the use of emissionproducing equipment. This is demonstrated by the NRCS Energy Estimator: Tillage Tool 

(USDA-NRCS 2011). For example, the tool estimates potential fuel savings of 3,010 gallons or 

60% savings per year based upon producing 1,000 acres of no-till soybean compared to 

conventional till soybean in the Urbana, Illinois postal code. NRCS is careful to note that this 

estimate is only approximate, as many variables could affect an individual operation’s actual 

savings. Reduced tillage also generates fewer particulates (dust) and potentially contributes to 

lower rates of wind erosion releasing soil particulates into the air, benefitting air quality (Towery 

and Werblow 2010).

Cotton

Cotton ginning produces particulate matter, such as lint, dust, fine leaves and other trash that 

affect air quality (EPA AP-42 chapter 9). The effects of cotton ginning on air quality are being 

assessed in a comprehensive four-year cotton gin dust sampling study by USDA and cotton 

academics (USDA-ARS 2013a; b).

II.C.4. Climate Change

Climate change represents a statistical change in climate conditions, and may be measured 

across both time and space. Agriculture may influence climate change through various facets of 

the production process. Combustion of fossil fuels in mechanized farm equipment, fertilizer 

application, and decomposition of agricultural waste products may all contribute greenhouse 

gases to the atmosphere. Greenhouse gases collectively function as retainers of solar radiation, 

and agriculture-related activities are recognized as both direct (e.g., exhaust from equipment) 

and indirect (e.g., agricultural-related soil disturbance) sources of carbon dioxide (CO2), methane 

(CH4), and N2O.

The major sources of GHG emissions associated with crop production are soil N2O emissions, 

soil CO2and CH4fluxes, and CO2emissions associated with agricultural inputs and farm 

equipment operation (Adler, et al. 2007; Del Grosso, et al. 2002; Robertson, et al. 2000; West 

and Marland 2002). Over the twenty-year period of 1990 to 2009, total emissions from the 

agricultural sector grew by 8.7%, with 7% of the total U.S. GHG emissions in 2009 generated 

from this sector (U.S. EPA 2011d). Agriculture, including land-use changes for farming, is 

responsible for an estimated 17% to 32% of all human-induced GHG emissions worldwide

(USDA Petition Number 09-082-01p). Generation of GHGs may have long term impacts on 

climate change as they function as retainers of solar radiation. 

CH4and N2O are the primary GHGs emitted by agricultural activities. Emissions from 

intestinal (enteric) fermentation and manure management represent about 20% and 7% of total 

CH4emissions from anthropogenic activities, respectively. Agricultural soil management 

activities including fertilizer application and cropping practices were the largest source of N2O 

emissions, accounting for 69% of all U.S. N2O emissions (U.S. EPA 2011d). 

Tillage contributes to the release of greenhouse gases (GHG) because of the loss of carbon 

dioxide to the atmosphere and the exposure and oxidation of soil organic matter (Baker, et al., 
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2005). In general, conservation tillage strategies are associated with more stable and increased 

carbon sequestration due to a net reduction in CO2emissions (Lal and Bruce 1999; West and 

Marland 2002). Conservation tillage is also associated with reduced CO2emissions from lower 

farm equipment operations. Herro (Herro 2008) proposes that if agriculture practices were 

modified, significant reductions in the release of GHGs could be achieved. 

Global climate change may also affect agricultural crop production (Karl, et al. 2009). These 

potential impacts on the agro-environment and individual crops may be direct, including 

changing patterns in precipitation, temperature, and duration of growing season, or may cause 

indirect impacts influencing weed and pest pressure (Rosenzweig, et al. 2001; Schmidhuber and 

Tubiello 2007). The impacts of GE crop varieties on climate change are unclear, though it is 

likely dependent on cropping systems, production practices, geographic distribution of 

activities, and individual grower decisions. The potential impact of climate change on 

agricultural output, however, has been examined in more detail. A recent Intergovernmental 

Panel on Climate Change (IPCC) forecast (2007) for aggregate North American impacts on 

agriculture from climate change actually projects yield increases of 5 to 20 percent for this 

century. The IPCC report notes that certain regions of the U.S. will be more heavily impacted 

because water resources may be substantially reduced. While agricultural impacts on existing 

crops may be substantial, North American production is expected to adapt with improved 

cultivars and responsive farm management (2007).

II.D. BIOLOGICAL RESOURCES

II.D.1. Biological Resources - Soybean

II.D.1.a. Animal Communities

Soybean production systems in agriculture are host to many animal species including deer, 

groundhogs, rabbits, raccoons, geese and small rodents. Mammals and birds, including 

migratory mammals and birds, may seasonally consume grain (Galle, et al. 2009), and 

invertebrates can feed on the plant during the entire growing season. Management of insects in 

soybean production fields is discussed in Section II.B.1.d. Animals protected as threatened or 

endangered species are discussed in Section VI.

Animals that feed primarily on soybean are seed-feeding insects and rodents found in 

agricultural fields. Crop pest insects are considered less problematic than weeds in U.S. 

soybean production as indicated by the low percentage (14%) of soybean acreage that receives 

insecticide treatment (USDA-NASS 2007). Some rodents, such as mice or squirrels, may 

seasonally feed exclusively on soybean seeds. Thus, these animals may have a diet containing 

significant amounts of soybean seeds. Deer may also browse in soybean fields on the forage 

and on seed left after harvest. 

Intensive agricultural lands, such as those used in crop production, usually have low levels of 

biodiversity compared with adjacent natural areas (Lovett, et al. 2003). Tillage, seed bed 

preparation, planting of a monoculture crop, pesticide use, fertilizer use, and harvest result in 

limited habitat and a correspondingly limited diversity of plants and animals on agricultural land 

(Lovett et al. 2003). However, the implementation of cropland management strategies can 

increase the value of crop fields to wildlife (Sharpe 2010). Some of these strategies include:
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 Conservation tillage and no-till practices have a positive impact on wildlife 

(Towery and Werblow 2010). Benefits include improved water quality, 

retention of cover, availability of waste grain on the soil surface for feed, and 

increased populations of invertebrates as a food source for turkey, quail, and 

songbirds (Sharpe 2010).

 Crop rotations can reduce the likelihood of crop disease, insect pests, weed 

pests, and the need for pesticides (University of California 2008). 

Beneficial insects within and near a soybean field include a wide variety of predators, which 

catch and eat smaller insects and parasitic insects that live on or in the body of other insects 

during at least one stage of their life cycle. Pollinators are important for some crops; however, 

soybean generally is not a preferred plant for pollinators (Abrams, et al. 1978; Erickson 1975; 

Jaycox 1970a; c; b). Other beneficial organisms, including earthworms, termites, ants, beetles, 

millipedes, and others contribute to the decay of organic matter and the cycling of soil nutrients 

(Ruiz, et al. 2008).

Animals that feed outside soybean fields are also considered in this section. The environment 

surrounding a soybean field, which may vary in plant composition depending on the region, 

may serve as a food source and habitat for mammals, birds, fish and insects. In certain areas, 

soybean fields may be bordered by other soybean, corn, or other crops; soybean fields may also 

be surrounded by woods and/or pasture/grassland areas, as well as aquatic environments. 

Therefore, the types of vegetation, including weeds, around a soybean field depend on the area 

where the soybean is planted. Fertilizers and/or water containing pesticides have the potential 

to run off into adjacent lands, pesticides also have the potential to move outside of the 

agroecosystem from drift and offsite movement. Regardless of the agricultural operation, 

animals and insects outside the field have the potential to be impacted directly from the use of 

fertilizers, pesticides, and erosion caused from agricultural operations, or indirectly, both 

positively and negatively, from effects on the plant community outside the soybean field.

II.D.1.b. Plant Communities 

The affected environment for growing soybean plants can generally be considered the 

agroecosystem (managed agricultural fields) plus some area extending beyond intended 

plantings. Plants, extraneous to the crop, which grow in planted fields can be considered weeds 

and are addressed in Section II.B.1.d. Animals protected as threatened or endangered species 

are discussed in Section VI.

Plants growing outside soybean fields are considered in this section. The environment 

surrounding a soybean field varies in plant composition depending on the region. In certain 

areas, soybean fields may be bordered by other soybean, corn, or other crops; fields may also be 

surrounded by woods and/or pasture/grassland areas, as well as aquatic environments. 

Therefore, the types of vegetation, including weeds, around a soybean field depend on the area 

where the soybean is planted. A variety of weeds and other vegetation dwell in and around 

soybean fields; those species may also vary depending on the region where the soybean is 

planted. These plants may be found in ditches, hedge rows, fence rows, wind breaks, yards, and 

other uncultivated areas, and may be annuals, biennials or perennials. Regardless of the 

agricultural operation, these plants may be impacted, both positively and negatively, by 
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agricultural operations. Fertilizers and/or water have the potential to run off into adjacent 

lands, resulting in increased plant growth outside the agroecosystem. Herbicides are commonly 

used in the production of soybean; a more detailed discussion of their use can be found in 

Section II.B.1.d and in Appendix A. Impacts on adjacent agricultural crops and nonagricultural plants can occur from offsite movement of any herbicide. These impacts are 

actively managed by farmers and applicators trained to use such products consistent with 

product labels and other state or local restrictions. Depending upon the herbicide, factors for 

managing the potential for drift and offsite movement include the selectivity and sensitivity of 

the herbicide, local weather conditions at the time of application (e.g., wind, temperature, 

humidity, inversion potential), droplet size distribution, application volume, boom height (i.e., 

height of the application equipment above the crop canopy), sprayer speed, and distance from 

the edge of the application area (Felsot et al. 2010; SDTF 1997). A variety of measures can be 

employed to effectively control the potential for spray drift and offsite movement, including 

nozzle selection and application techniques and restrictions. 

Another potential component of herbicide offsite movement is volatility, which is primarily a 

function of the physicochemical properties of the chemical, (e.g., vapor pressure, Henry’s Law 

constant, etc.), method of application (e.g., soil-incorporated or not), and the local 

environmental conditions (e.g., temperature, humidity, wind speed). Low-volatility forumations 

can reduce volatility and offsite movement. For example, side-by-side field experiments have 

indicated that a formulation of the diglycolamine (DGA) salt of dicamba volatilized significantly 

less than a similar formulation of the DMA salt form (Egan and Mortensen 2012). Measured 

air concentrations when using the DGA salt were 30- to 50-fold lower than concentrations of

the potassium and DMA salts of dicamba from laboratory studies EFED evaluated, even 

though the application rate was twice that of DMA (Mueller 2010).

Additionally, pesticide registrants must report drift incidents to EPA as an adverse effect in 

order to ensure the pesticide continues to meet FIFRA requirements for registration. 40 C.F.R. 

§ 159.195(a)(2). Before any registered herbicide can be applied to any new use site (including 

any deregulated GE-derived crop), EPA must approve a label amendment setting out the use 

pattern and specific application requirements for that new use site. Specifically, in order to 

approve a new use of a pesticide , EPA must conclude that no unreasonable adverse effects will 

result from the new use when applied according to label directions, which includes potential 

offsite movement. Offsite impacts are diminished when herbicides are applied in accordance 

with label instructions. Registered herbicides, including dicamba and glufosinate, are assessed 

by EPA for potential risks to non-target plants. A detailed discussion of the use of dicamba 

herbicide in the U.S. can be found in Appendix A.

Finally, soybeans infrequently occur as a volunteer when soybean seeds remain in a field 

following harvesting and may be considered a weed in the subsequent crop. Volunteer soybean 

in rotational crops is not a concern in the Midwest region because the soybean seed is typically 

not viable after the winter period (Carpenter et al. 2002; OECD 2000b). In southern soybean 

growing areas of the U.S. where the winter temperatures are milder, it is possible for soybean 

seed to remain viable over the winter and germinate the following spring. If volunteer soybean 

should emerge after planting, shallow cultivation and/or use of another herbicide will control 

volunteers and effectively reduce competition with the crop. Several postemergence herbicides 

are also available to control volunteer soybean (either conventional or herbicide-tolerant 

soybean) in each of the major soybean rotational crops. Therefore, due to the availability of 
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adequate control measures for volunteer soybean, volunteer soybean normally is not a concern 

in rotational crops, such as corn, cotton, rice and small grains (e.g., wheat, barley, sorghum and 

oats), which are the primary rotational crops following soybean (Carpenter et al. 2002; OECD 

2000b).

II.D.1.c. Gene Flow and Weediness

Gene introgression is a process whereby one or more genes successfully integrate into the 

genome of a recipient plant population. Introgression is affected by many factors, including the 

frequency of the initial pollination event, environmental factors, sexual compatibility of pollen 

donor and recipient plants, pollination biology, flowering phenology, hybrid stability and 

fertility, selection, and the ability to backcross repeatedly. Because gene introgression is a 

natural biological process, it does not constitute an environmental risk in and of itself 

(Sutherland and Poppy 2005). Gene introgression must be considered in the context of the 

transgene(s) inserted into the biotechnology-derived plant, and the likelihood that the presence 

of the transgene(s) and their subsequent transfer to recipient plants will result in increased plant 

pest potential. The potential for gene introgression from DT soybean is discussed below.

The assessment for gene introgression from DT soybean with other cultivated or wild relatives 

of soybean, discussed in detail below, indicates that DT soybean is no more likely to become a 

weed than conventional soybean, and DT soybean is expected to be similar to conventional 

soybean regarding its potential for and impacts from gene flow. Soybean lacks sexuallycompatible relatives in the U.S.; therefore, the only pollen-mediated gene flow would be within 

cultivated soybean.

Hybridization with Cultivated Soybean: Although soybean is largely a self-pollinated 

species, low levels of natural cross-pollination can occur (Caviness 1966; OECD 2000b; Ray, et 

al. 2003; Yoshimura, et al. 2006). In studies with cultivated soybean, where conditions have 

been optimized to ensure close proximity and flowering synchrony, natural cross-pollination 

generally has been found to be very low. Most outcrossing occurred with surrounding plants, 

and cross-pollination frequencies varied depending on growing season and genotype. Insect 

activity does increase the outcrossing rate, but soybean generally is not a preferred plant for 

pollinators (Abrams et al. 1978; Erickson 1975; Jaycox 1970a; c; b). 

Numerous studies on soybean cross-pollination have been conducted, and the published 

results, with and without supplemental pollinators, are summarized in Table II.D-1. Under 

natural conditions, cross-pollination among adjacent plants in a row or among plants in 

adjacent rows ranged from 0 to 6.3%. In experiments where supplemental pollinators (usually 

bees) were added to the experimental area, cross-pollination ranged from 0.5 to 7.74% in 

adjacent plants or adjacent rows. However, cross-pollination does not occur at these levels 

over long distances. Cross-pollination rates decrease to less than 1.5% beyond one meter from 

the pollen source, and rapidly decrease with greater distances from the source. The following 

cross-pollination rates at extended distances have been reported: 0.05% at 5.4 meters (Ray et al. 

2003), 0% at 6.5 meters (Abud, et al. 2003), 0% at 10.5 m (Yoshimura et al. 2006), and 0.004% 

at 13.7 meters of separation (Caviness 1966). 

The potential for cross-pollination in soybean is limited. This is recognized in certified seed 

regulations for foundation seed in the U.S., which permit any distance between different 
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soybean cultivars in the field as long as the distance is adequate to prevent mechanical mixing 

(USDA-APHIS 2006).

The consequence of introgression of the dicamba tolerance trait from DT soybean into other 

soybean is negligible since soybean gene flow is naturally low; therefore the dicamba tolerance 

trait confers no increased plant pest potential to cultivated soybean.
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Table II.D-1. Summary of Published Literature on Soybean Cross Pollination

Distance from 

Pollen Source 

(meters)

CrossPollination (%) Comments Reference

0.3 0.04 (estimated 

per pod)

Interspaced plants within a row. Experiment 

conducted in a single year. Single male and 

female parental varieties. Percent outcrossing 

calculated per pod rather than per seed. 

(Woodworth 

1922)

0.8 0.07 to 0.18 Adjacent rows. Experiment conducted over two 

years. Several male and female parental varieties. 

(Garber and 

Odland 1926)

0.1 0.38 to 2.43 Adjacent plants within a row. Experiment 

conducted in a single year. Several male and 

female parental varieties.

(Cutler 1934)

0.1 0.2 to 1.2 Adjacent plants within a row. Experiment 

conducted in single year at two locations. 

Several male and female parental varieties.

(Weber and 

Hanson 1961)

0.9

2.7–4.6 

6.4–8.2 

10–15.5 

0.03 to 0.44 

0.007 to 0.06

0 to 0.02

0 to 0.01

Frequency by distance was investigated. 

Experiment conducted over three years. Single 

male and female parental varieties.

(Caviness 

1966)

0.8 m 0.3 to 3.62 Various arrangements within and among 

adjacent rows. Experiment conducted over 

three years. Several male and female parental 

varieties.

(Beard and 

Knowles 1971)

One row

(undefined)

1.15 to 7.74 Bee pollination of single-row, small-plots of 

pollen receptor surrounded by large fields 

(several acres) of pollen donor soybean. 

Soybean is not a preferred flower for alfalfa 

leafcutting bees. 

(Abrams et al. 

1978)

0.1–0.6 0.5 to 1.03 

(depending on 

planting design)

Bee pollination of soybean grown in various 

spatial arrangements. Experiment conducted 

over four years. Several soybean cultivars. 

(Chiang and 

Kiang 1987)

1.0 0.09 to 1.63 Adjacent rows. Experiment conducted over two 

years. Several male and female parental varieties. 

(Ahrent and 

Caviness 1994)

0.5 

1.0 

6.5 

0.44 to 0.45

0.04 to 0.14

none detected

Frequency by distance was investigated. 

Experiment conducted in a single year. 

Single male and female parental varieties.

(Abud et al. 

2003)

0.9 

5.4 

0.29 to 0.41

0.03 to 0.05

Frequency by distance was investigated. 

Experiment conducted in a single year. Single 

male and female parental varieties.

(Ray et al. 

2003)

0.15 0.65 to 6.32

(avg. 1.8)

Interspaced plants within a row. Experiment 

conducted in a single year. Single male and 

female parental varieties.

(Ray et al. 

2003)

0.7 

1.4 

2.1 

2.8 

3.5 

7.0 

10.5 

0 to 0.19

0 to 0.04

0 to 0.05

0 to 0.08

0 to 0.04

0 to 0.04

0

Interspaced plants within a row arranged in small 

plots. Experiment conducted in a four year 

period. Single male and two female parental 

varieties.

(Yoshimura et 

al. 2006)
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Hybridization with Wild Species of Glycine Subgenus: As discussed in Section II.B.1.1, 

wild (native) Glycine species are endemic throughout much of Asia, but do not exist naturally in 

North America (OECD 2000b). Therefore, there is no potential for hybridization of soybean 

with wild species in the Americas.

The subgenus Soja includes the cultivated soybean Glycine max and the wild annual species 

Glycine soja. Glycine soja is found in China, Taiwan, Japan, Korea, and Russia and can hybridize 

naturally with the cultivated soybean, G. max (Hymowitz 2004; Lu 2004). However, Abe et al. 

(1999) note that “natural hybrids between G. max and G. soja are rare and hybrid swarms 

involving both species have never been reported.” This is also supported by work from 

Kuroda et al. (2008) in which molecular markers were used and no gene flow from G. max to 

G. soja was detected. Many barriers to natural hybridization exist between soybean and wild 

relatives, including the highly selfing nature of both plants, required proximity of wild soybean 

to cultivated soybean, synchrony of flowering, and presence of pollinators. As such, it is highly 

unlikely that naturally occurring, pollen-mediated gene flow and transgene introgression into 

wild soybean relatives from incidentally released biotechnology-derived soybean will occur at 

any meaningful frequency. 

Hybridization with Feral Species of Glycine Subgenus: Cultivated soybean seed rarely 

displays any dormancy characteristics and only under certain environmental conditions grows as 

a volunteer in the year following cultivation. If this should occur, volunteers do not compete 

well with the succeeding crop, and can easily be controlled mechanically or chemically. The 

soybean plant is not weedy in character. In North America, it is not found outside of 

cultivation. In managed ecosystems, soybean does not effectively compete with other 

cultivated plants or primary colonizers (OECD 2000a). 

II.D.1.d. Microorganisms

Soil microorganisms play a key role in soil structure formation, decomposition of organic 

matter, toxin removal, nutrient cycling, and most biochemical soil (Garbeva, et al. 2004). These 

microorganisms also suppress soil-borne plant diseases and promote plant growth (Doran, et al. 

1996). The main factors affecting microbial population size and diversity include soil type 

(texture, structure, organic matter, aggregate stability, pH, and nutrient content), plant type 

(providers of specific carbon and energy sources into the soil), and agricultural management 

practices (crop rotation, tillage, application of herbicide and fertilizer, and irrigation) (Garbeva 

et al. 2004). The occurrence and abundance of soil microorganisms are affected by 1) soil 

characteristics like tilth, organic matter, nutrient content, and moisture capacity, 2) typical 

physico-chemical factors such as temperature, pH, and redox potential, and 3) soil management 

practices. Agricultural practices such as fertilization and cultivation may also have profound 

effects on soil microbial populations, species composition, colonization, and associated 

biochemical processes (Buckley and Schmidt 2001; Buckley and Schmidt 2003). Consequently, 

significant variation in microbial populations is expected in agricultural fields.

Members of the bacterial family Rhizobiaceae and Bradyrhizobiaceae form a highly complex and 

specific symbiotic relationship with leguminous plants, including soybean (Gage 2004). The 

nitrogen-fixing plant-microbe symbiosis results in the formation of root nodules, which provide 

an environment in which differentiated bacteria called bacteroids are capable of reducing or 

“fixing” atmospheric nitrogen. The product of nitrogen fixation, ammonia, can then be utilized 
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by the plant. As a result of this relationship, nitrogen inputs are typically not necessary for 

agricultural production of soybeans.

II.D.1.e. Biodiversity

Tillage, seed bed preparation, planting of a monoculture crop, pesticide use, fertilizer use, and 

harvest may all limit the diversity of plants and animals on agricultural land (Lovett et al. 2003). 

Agricultural land subject to intensive farming practices, such as that used in crop production, 

generally has low levels of biodiversity compared with adjacent natural areas. Herbicide use in 

agricultural fields can indirectly impact biodiversity by decreasing weed species present in the 

field and those insects, birds and mammals that potentially rely on these weeds.

Conservation tillage practices can have a positive impact on wildlife, including beneficial 

arthropods (Landis, et al. 2005; Towery and Werblow 2010). Conservation tillage practices 

benefit biodiversity on agricultural land due to decreased soil erosion, improved surface water 

quality, retention of vegetative cover, increased food sources from crop residues and increased 

populations of invertebrates (Landis et al. 2005; Sharpe 2010).

Species diversity and abundance in soybean agroecosystems may differ between non-GE, GE, 

and organic production systems. Many studies over the last ten years have investigated the 

differences in biological diversity and abundance between GE and non-GE fields, particularly 

those GE crops that are resistant to insects (e.g., Bt crops) or herbicides (e.g., glyphosate-tolerant 

or glufosinate-tolerant crops). Among the numerous studies, conflicting results are often 

reported. The literature has demonstrated decreases in biological diversity or abundance due to 

GE crops engineered to accumulate insecticidal proteins or tolerate herbicide application for 

weed management (Pilcher, et al. 2005). Alternatively, other studies of GE crops, such as Bt

corn, when compared to non-GE crops sprayed with insecticides, demonstrate that GE crops 

do not cause any changes in arthropod abundance or diversity (Romeis, et al. 2004; Torres and 

Ruberson 2005; Wolfenbarger, et al. 2008). Some reports show that GE crops may even 

increase biological diversity in agroecosystems (Marvier, et al. 2007; Romeis, et al. 2006). Due 

to the multiple definitions of biological diversity, the determination of the level of biological 

diversity in any crop is complex; consensus on the measurement of diversity can be difficult to 

achieve. It can likewise be difficult in biodiversity studies to separate expected impacts from 

indirect ones. For example, reductions of biological control organisms are seen in some Btexpressing GE crops, but are caused by reduction of the pest population following cultivation 

of the insect-resistant GE crop plant.

II.D.2. Biological Resources – Cotton 

Modern conservation practices incorporated in cotton cultivation have brought a positive 

impact to animal and plant communities through reduced tillage, more carefully controlled and 

targeted chemical placement (fertilizers and pesticides), and better control of irrigation systems 

(CCI 2013; Cotton Inc. 2013). GE-based crop systems provide opportunities to optimize the 

introduction and implementation of many of these practices. For example, herbicide tolerance 

allows cultivation with minimal tillage required to control volunteers and weeds (Towery and 

Werblow 2010). This subsection provides an overview of the relationships of these practices to 

the biotic community.
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II.D.2.a. Animal Communities

Cotton production systems in agriculture are host to many animal species. Mammals and birds 

may use cotton fields and the surrounding vegetation for food and habitat throughout the year. 

Invertebrates can feed on cotton plants or prey upon other insects living on cotton plants, as 

well as in the vegetation surrounding cotton fields. Insects considered pests to cotton area 

addressed in Section II.B.2.d. Animals protected as threatened or endangered species are 

discussed in Section VI.

Intensive agricultural lands, such as those used in crop production, usually have low levels of 

biodiversity compared with adjacent natural areas (Lovett et al. 2003). Tillage, seed bed 

preparation, planting of a monoculture crop, pesticide use, fertilizer use, and harvest result in 

limited habitat and a correspondingly limited diversity of plants and animals on agricultural land 

(Lovett et al. 2003). However, the implementation of cropland management strategies can

increase the value of crop fields to wildlife (Sharpe 2010). Some of these strategies include:

 Conservation tillage and no-till practices have a positive impact on wildlife 

(Towery and Werblow 2010). Benefits include improved water quality, 

retention of cover, availability of waste grain on the soil surface for feed and 

increased populations of invertebrates as a food source for turkey, quail, and 

songbirds (Sharpe 2010).

 Crop rotations reduce the likelihood of crop disease, insect pests, weed pests, 

and the need for pesticides (University of California 2008). 

Although many of the invertebrate organisms found in or near cotton production fields are 

considered pests, such as the cotton bollworm and tobacco budworm, most invertebrates are 

considered beneficial (University of Arkansas 2006). Beneficial insects include a wide variety of 

predators, which catch and eat smaller insects and parasitic insects that live on or in the body of 

other insects during at least one stage of their life cycle. Other beneficial insects function as 

pollinators. Major pollinators of G. hirsutum are bumble bees (Bombus spp.), black bees 

(Melissodes spp.), and honey bees (Apis mellifera) (McGregor 1976). Other beneficial organisms, 

including earthworms, termites, ants, beetles, millipedes, and others contribute to the decay of 

organic matter and the cycling of soil nutrients (Ruiz et al. 2008).

Since the mid-1990s, GE herbicide-tolerant cotton lines have been commercialized without 

substantiated reports of significant deleterious impacts on non-target organisms (OECD 2007; 

U.S. EPA 2008a; USDA-APHIS 2010b).

II.D.2.b. Plant Communities

The affected environment for growing cotton plants can generally be considered the 

agroecosystem (managed agricultural fields), plus some area extending beyond intended 

plantings. Plants, extraneous to the crops that grow in planted fields, can be considered weeds 

and are addressed in Section II.B.2.d. Plants protected as threatened or endangered species are 

discussed in Section VI.
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The landscape surrounding a cotton field varies depending on the region. In certain areas, 

cotton fields may be bordered by other cotton (or other crop) fields or may also be surrounded 

by woodland, rangelands, and/or pasture/grassland areas. These plant communities may be 

natural or managed plant habitats for the control of soil and wind erosion and serve as wildlife 

habitats.

Surrounding plants may be impacted, both positively and negatively, by agricultural operations. 

Fertilizers and/or water may run off into adjacent lands, resulting in increased plant growth 

outside the field margins. 

Herbicides are commonly used in the production of cotton; a more detailed discussion of their 

use can be found in Section II.B.2.d and Appendix A. Impacts on adjacent agricultural crops 

and non-agricultural plants can occur from offsite movement of any herbicide. These impacts 

are actively managed by farmers and applicators trained to use such products consistent with 

product labels and other state or local restrictions. Depending upon the herbicide, factors for 

managing the potential for drift and offsite movement include the selectivity and sensitivity of 

the herbicide, local weather conditions at the time of application (e.g., wind, temperature, 

humidity, inversion potential), droplet size distribution, application volume, boom height (i.e., 

height of the application equipment above the crop canopy), sprayer speed, and distance from 

the edge of the application area (Felsot et al. 2010; SDTF 1997). A variety of measures can be 

employed to effectively control the potential for spray drift and offsite movement, including 

nozzle selection and application techniques and restrictions, see Appendix D for additional 

detail.

Another potential component of herbicide offsite movement is volatility, which is primarily a 

function of the physicochemical properties of the chemical, (e.g., vapor pressure, Henry’s Law 

constant, etc.), method of application (e.g., soil-incorporated or not), and the local 

environmental conditions (e.g., temperature, humidity, wind speed). Low-volatility forumations 

can reduce volatility and offsite movement. For example, side-by-side field experiments have 

indicated that a formulation of the diglycolamine (DGA) salt of dicamba volatilized significantly 

less than a similar formulation of the DMA salt form (Egan and Mortensen 2012). Measured 

air concentrations when using the DGA salt were 30- to 50-fold lower than those in the 

potassium and DMA salt laboratory studies EFED evaluated, even though the application rate 

was twice that of DMA (Mueller 2010).

EPA considers possible effects from offsite movement as part of the pesticide registration 

process required under FIFRA. Additionally, pesticide registrants must report drift incidents to 

EPA as an adverse effect in order to ensure the pesticide continues to meet FIFRA 

requirements for registration. 40 C.F.R. § 159.195(a)(2). Before any registered herbicide can be 

applied to any new use site (including any deregulated GE-derived crop), EPA must approve a 

label amendment setting out the use pattern and specific application requirementsfor that new 

use site. Specifically, in order to approve a new use of a pesticide , EPA must conclude that no 

unreasonable adverse effects will result from the new use when applied according to label 

directions, which includes potential offsite movement. Offsite impacts are diminished when 

herbicides are applied in accordance with label instructions. Registered herbicides, including 

dicamba and glufosinate, are reassessed by EPA for potential risks to non-target plants. A 

detailed discussion of the use of dicamba and glufosinate herbicides in the U.S. can be found in 

Section II.B.2.d.
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II.D.2.c. Gene Flow and Weediness

Gene flow is a biological process that facilitates the production of hybrid plants, introgression 

of novel alleles (i.e., versions of a gene) into a population, and the evolution of new plant 

genotypes. Gene flow to and from an agro-ecosystem can occur on both spatial and temporal 

scales. In general, plant pollen tends to represent the major reproductive method for moving 

across areas, while both seed and vegetative propagation tend to promote the movement of 

genes across time and space. 

The rate and success of gene flow is dependent on numerous external factors in addition to the 

donor/recipient plant. General external factors related to pollen-mediated gene flow include 

the presence/abundance/distance of sexually-compatible plant species; overlap of flowering 

phenology between populations; the method of pollination; the biology and amount of pollen 

produced; and weather conditions, including temperature, wind, and humidity (Mallory-Smith 

and Zapiola 2008). Seed-mediated gene flow also depends on many factors, including the 

absence/presence/magnitude of seed dormancy; contribution and participation in various 

dispersal pathways; and environmental conditions and events.

Hybridization with Cultivated Cotton: Although natural outcrossing can occur, cotton is 

normally considered to be a self-pollinating crop (Niles and Feaster 1984; OECD 2008). There 

are no morphological barriers to cross-pollination based on flower structure. However, the 

pollen is heavy and sticky, and transfer by wind is limited. Pollen is transferred instead by 

insects, and particularly by various wild bees, bumble bees (Bombus spp.), and honeybees (Apis 

mellifera). Numerous studies on cotton cross-pollination have been conducted, and the 

published results, with and without supplemental pollinators, are summarized in Table II.D-2. 

The recent cotton literature discussed below shows that the frequency of cross-pollination 

decreases with distance from the pollen source. McGregor (1976) traced movement of pollen 

by means of fluorescent particles and found that, even among flowers located only 150 to 200 

feet from a cotton field that was surrounded by a large number of bee colonies to ensure ample 

opportunity for transfer of pollen, fluorescent particles were detected on only 1.6% of the 

flowers. In a 1996 study with various field designs, Llewellyn and Fitt (1996) also found low 

levels of cross-pollination in cotton. At one meter from the source they observed crosspollination frequencies of 0.15 to 0.4%, decreasing to below 0.3% at 16 meters from the source. 

Umbeck et al. (1991) used a selectable marker to examine cross-pollination from a 30 x 136 

meter source of GE-derived cotton. Cross-pollination decreased from five to less than one 

percent from one to seven meters, respectively, away from the source plot. A low level of 

cross-pollination (less than one percent) was sporadically detected to the furthest sampling 

distance of 25 meters. Berkey et al. (2002) reported that cross pollination between fields 

separated by a 13 foot road decreased from 1.89% in the row nearest the source to zero percent 

in the 24th row. Van Deynze et al. (2005) conducted a two year study on pollen-mediated gene 

flow with high and low pollinator activity. In the presence of high pollinator activity, the 

pollination frequency was 7.65% at 0.3 meters and less than 1% at greater than nine meters, 

whereas the pollination frequency with low pollinator activity was below 1% at just over a 

meter. In a 2008 study pollination frequencies of 5.00% and 0.00% were demonstrated at 1 and 

8 meters, respectively (Kairichi, et al. 2008). By comparison, the isolation distances for 

Foundation, Registered, and Certified seeds in 7 CFR Part 201 are 1320, 1320, and 660 feet, 

respectively(USDA-AMS 2010). 
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Table II.D-2. Summary of Published Literature on Cotton Cross Pollination

Distance 

from Pollen 

Source 

(meters)

CrossPollination 

(%) Comments Reference

45-61 1.60%

Used fluorescent particles to follow 

pollinator movement in cotton fields 

over one season.

(McGregor 1976)

1 0.15-0.4% Used a selectable marker to examine 

cross-pollination in the progeny of 

buffer row plants over one season.

(Llewellyn and Fitt 

1996)

4 <0.08%

16 <0.03%

1 5% Used a selectable marker to examine 

cross-pollination from a 20 x 136 meter 

source of biotechnology-derived cotton 

over one season.

(Umbeck et al. 1991)

1-25

<1%

5 1.89%

Used herbicide bioefficacy to examine 

pollen flow between fields separated by 

a 13 foot road over one season. 

(Berkey et al. 2002)

10.5 0.77%

17 0.13%

25 0.00%

0.3 7.65% * Used herbicide bioefficacy confirmed 

by DNA testing to measured pollenmediated gene flowing in four 

directions over 2 years.

(Van Deynze et al. 

2005)

>9 < 1% *

>1 < 1% **

1625 0.04% **

1 5.00% Used ELISA strips to examine pollenmediated gene flow in four directions 

from Bt source over a period of one 

season.

(Kairichi et al. 2008)

2-7 2.00%

8 0.00%

* High pollinator activity

** Low pollinator activity

Hybridization with Wild Gossypium Species: Only two ‘wild’ (native) Gossypium species 

related to cultivated cotton are known to be present in the U.S.: G. thurberi Todaro, which is 

found in Arizona (Fryxell 1984) and G. tomentosum, which is endemic to Hawaii. Based on 

cytological evidence, seven genomic types, A through G, many with subtypes, have been 

identified for the genus Gossypium (Endrizzi, et al. 1984). The domesticated species G. hirsutum 

and G. barbadense are allotetraploid (AADD, 2n=4x=52), while G. thurberi is a diploid (DD, 

2n=2x=26), and G. tomentosum is an allotetraploid (AADD, 2n=4x=52). Only G. tomentosum is 

considered to be capable of crossing with domesticated cotton to produce fertile offspring 

(Waghmare, et al. 2005). 
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However, domesticated cotton is not grown commercially in Hawaii, with the exception of 

potential counter-season breeding nurseries where appropriate isolation distances and practices 

are utilized (Bates 1990). Thus, the potential for gene flow to these wild relatives is limited. 

Hybridization with Feral Gossypium Species: The inability of plants or seeds of either G. 

hirsutum or G. barbadense to survive freezing temperatures restricts their persistence as perennials 

or recurrent annuals to tropical areas (U.S. EPA 2013e), where cotton is not grown. Feral G. 

hirsutum occurs in parts of southern Florida in the Everglades National Park and the Florida 

Keys and in Puerto Rico, several hundred miles from commercial cotton production areas 

(Brubaker et al. 1999; U.S. EPA 2013e).

II.D.2.d. Microorganisms

Soil microorganisms play a key role in soil structure formation, decomposition of organic 

matter, toxin removal, nutrient cycling, and most biochemical soil (Garbeva et al. 2004). These 

microorganisms also suppress soil-borne plant diseases and promote plant growth (Doran et al. 

1996). The main factors affecting microbial population size and diversity include soil type 

(texture, structure, organic matter, aggregate stability, pH, and nutrient content), plant type 

(providers of specific carbon and energy sources into the soil), and agricultural management 

practices (crop rotation, tillage, application of herbicide and fertilizer, and irrigation) (Garbeva 

et al. 2004). Plant roots, including those of cotton, release a variety of compounds into the soil, 

creating a unique environment for microorganisms in the rhizosphere. Microbial diversity in the 

rhizosphere may be extensive and differs from the microbial community in the bulk soil 

(Garbeva et al. 2004). 

The occurrence and abundance of soil microorganisms are affected by 1) soil characteristics like 

tilth, organic matter, nutrient content, and moisture capacity, 2) typical physico-chemical factors 

such as temperature, pH, and redox potential, and 3) soil management practices. Agricultural 

practices such as fertilization and cultivation may also have profound effects on soil microbial 

populations, species composition, colonization, and associated biochemical processes (Buckley 

and Schmidt 2001; Buckley and Schmidt 2003). Consequently, significant variation in microbial 

populations is expected in agricultural fields. Agricultural practices such as fertilization and 

cultivation may also have profound effects on soil microbial populations, species composition, 

colonization, and associated biochemical processes (Buckley and Schmidt 2001; Buckley and 

Schmidt 2003). Consequently, significant variation in microbial populations is expected in 

agricultural fields.

II.D.2.e. Biodiversity

Biodiversity is strongly impacted by agricultural practices, including the type of cultivated plant 

and its associated management practices. Agricultural land subject to intensive farming 

practices, such as that used in crop production, generally has low levels of biodiversity 

compared with adjacent natural areas. 

Tillage, seed bed preparation, planting of a monoculture crop, pesticide use, fertilizer use, and 

harvest may all limit the diversity of plants and animals on agricultural land (Lovett et al. 2003). 

Herbicide use in agricultural fields can indirectly impact biodiversity by decreasing weed species 

present in the field and those insects, birds and mammals that potentially rely on these weeds.
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Conservation tillage practices can have a positive impact on wildlife, including beneficial 

arthropods (Landis et al. 2005; Towery and Werblow 2010). Conservation tillage practices 

benefit biodiversity due to decreased soil erosion, improved surface water quality, retention of 

vegetative cover, increased food sources from crop residues and increased populations of 

invertebrates (Landis et al. 2005; Sharpe 2010).

Species diversity and abundance in cotton agroecosystems may differ between non-GE, GE, 

and organic production systems. Many studies over the last ten years have investigated the 

differences in biological diversity and abundance between GE and non-GE fields, particularly 

those GE crops that are resistant to insects (e.g., Bt crops) or herbicides (e.g., glyphosate-tolerant 

or glufosinate-tolerant crops). Among the numerous studies, conflicting results are often 

reported. The literature has demonstrated decreases in biological diversity or abundance due to 

GE crops engineered to accumulate insecticidal proteins or tolerate herbicide application for 

weed management (Pilcher et al. 2005)). Alternatively, other studies of GE crops, such as Bt

corn, when compared to non-GE crops sprayed with insecticides, demonstrate that GE crops 

do not cause any changes in arthropod abundance or diversity (Romeis et al. 2004; Torres and 

Ruberson 2005; Wolfenbarger et al. 2008). Some reports show that GE crops may even 

increase biological diversity in agroecosystems (Marvier et al. 2007; Romeis et al. 2006). Insectresistant cotton, when compared to non-GE cotton production, may not result in changes in 

non-target arthropod abundance and may increase species diversity during different times of 

the year (Carpenter 2011; Sisterson, et al. 2007). Due to the multiple definitions of biological 

diversity, the determination of the level of biological diversity in any crop is complex; 

consensus on the measurement of diversity can be difficult to achieve. It can likewise be 

difficult in biodiversity studies to separate expected impacts from indirect ones. For example, 

reductions of biological control organisms are seen in some Bt-expressing GE crops, but are 

caused by reduction of the pest population following cultivation of the insect-resistant GE crop 

plant.

II.E. HUMAN HEALTH

The affected environment in terms of human health and safety related to soybeans and cotton 

includes all aspects of direct and indirect human contact with soybeans and cotton. Pesticide 

use on soybean and cotton products is also relevant both from a human consumption and 

worker safety standpoint. 

As discussed elsewhere in this report, Congress transferred regulatory authority over herbicides 

from USDA to EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or 

herbicide resistance, and no authority to consider herbicide impacts under the PPA. APHIS 

indicated in its Notice of Intent to Prepare an Environmental Impact Statement (78 Fed. Reg. 

28796, May 16, 2013) that it would be considering herbicide effects and herbicide resistance as 

part of the NEPA process, however Monsanto believes that APHIS has no legal obligation 

under NEPA to consider herbicide impacts or herbicide resistance in any Environmental 

Impact Statement or Environmental Assessment. See DOT v. Public Citizen, 541 U.S. 752, 770, 

769 (2004) (where an agency has no ability to prevent a certain effect due to its limited statutory 

authority over the relevant actions, the agency cannot be considered a legally relevant “cause” 

of the effect, and is therefore not required to analyze the environmental impact of an action it 

could not refuse to perform). See also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. 

App. LEXIS 9920, at *16-17 (9th Cir. 2013) (“If APHIS concludes that the presumptive plant 
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pest does not exhibit any risk of plant pest harm, APHIS must deregulate it since the agency 

does not have jurisdiction to regulate organisms that are not plant pests.”). Nonetheless, 

because APHIS indicated its intention to address herbicide-related impacts, Monsanto has 

included a discussion of herbicide impacts in Appendix F.

II.E.1. Consumer Health

Under the Federal Food, Drug, and Cosmetic Act (FFDCA), it is the responsibility of food 

manufacturers to ensure that the ingredients and products they market are safe and properly 

labeled. Food and feeds derived from GE cotton and GE soybeans must be in compliance 

with all applicable legal and regulatory requirements. GE crops used for food or feed purposes 

undergo a voluntary consultation process with the FDA prior to release onto the market (21 

CFR Parts 192 and 592) (U.S. FDA 2001b). Although this consultation is a voluntary process, 

thus far developers who intend to commercialize a GE crop that will be used for food or feed 

have completed a consultation with the FDA. In a consultation, a developer who intends to 

commercialize a GE crop meets with the agency to identify and discuss relevant safety, 

nutritional, or other regulatory issues regarding the food and feed derived from that crop. The 

developer then submits to FDA a scientific and regulatory assessment summary of the food and 

feed safety of the product. FDA evaluates the submission and responds to the developer by 

letter (U.S. FDA 2010). All GE cotton and soybean products on the market today have 

satisfactorily completed the FDA consultation process established to review the safety of foods 

and feeds derived from GE crops for human and animal consumption. Several international 

agencies also review food safety associated with GE-derived food items, including the 

European Food Safety Agency (EFSA) and the Food Standards Australia and New Zealand 

(FSANZ). Food safety reviews frequently will compare the compositional characteristics of the 

GE crop with nontransgenic, conventional varieties of that crop (Aumaitre, et al. 2002; Codex 

Alimentarius 2009). Moreover, this comparison also evaluates the composition of the modified 

crop under actual agronomic conditions, including various agronomic inputs. Composition 

characteristics evaluated in these comparative tests include moisture, protein, fat, carbohydrates, 

ash, minerals, dietary fiber, essential and non-essential amino acids, fatty acids, vitamins, and 

antinutrients.

As noted by the National Research Council (NRC), compositional changes can arise with all 

forms of genetic modification, including both traditional breeding and genetic engineering 

(NRC 2004). However, the NRC also noted that no adverse health effects attributed to genetic 

engineering had been documented in the human population. Reviews on the nutritional quality 

of GE-derived foods have generally concluded that there are no significant nutritional 

differences in conventional versus GE-derived plants for food or animal feed (Faust 2002; 

Flachowsky, et al. 2005). 

II.E.1.a. Soybeans

Humans consume soybeans and have done so for thousands of years. Soybean is a highly 

versatile crop which can be processed into a wide variety of food products. Soybean protein is 

used to enhance nutrition in a wide variety of food products, such as breakfast cereals and 

pasta. Soybean protein is also an important component in baked goods, alternative meat 

products, soups, energy bars, nutritional beverages, infant formula and dairy replacement 

products (USB 2011a). Soybean oil constitutes the majority (68%) of consumed edible fats and 
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oils in the U.S. (ASA 2011). It is present in numerous food products including cooking oils, 

shortening, margarine, mayonnaise, salad dressings and a wide variety of fat or oil-based 

products (USB 2011a). Soybean improved with new traits produced by biotechnology pose no 

unique risks relative to other soybean developed using traditional breeding methods. 

Biotechnology-derived soybean is evaluated extensively prior to commercial introduction. 

II.E.1.b. Cotton

Cotton fiber is most often used in the manufacture of a variety of textiles, and processed cotton 

fibers are used in pharmaceutical and medical applications because of their low capacity to 

cause irritation (OECD 2008). The highest grade linters, highly processed fiber, can also be 

used in the manufacturing of absorbent cotton, medical pads, and gauze (NCPA 2002). After 

ginning to remove fibers for textile manufacturing, cottonseed is processed into four major 

products: oil, meal, hulls, and linters. Processing of cottonseed typically yields (by weight): 16% 

oil, 45% meal, 26% hulls, and 9% linters, with 4% lost during processing (Cherry 1983). Due 

to the presence of anti-nutrients in cottonseed, including gossypol, and cyclopropenoid fatty

acids, only highly refined products (refined, bleached, and deodorized (RBD) oil and linters) are 

suitable for human consumption. The levels of these anti-nutrients are drastically reduced 

during processing (AOCS 2009; Harris 1981; NCPA 1993). 

Approximately 56% of cottonseed oil is used for salad or cooking oil, 36% for baking and 

frying fats, and the remaining 8% goes into margarine and other uses (OECD 2009). In 

addition, linters or cotton fiber may be minor ingredients in processed meats (sausage casing), 

ice cream, salad oil and other foods (OECD 2009). Approximately 835 million pounds of 

cottonseed oil was produced in the U.S. in 2010/2011. By comparison, U.S. production of 

soybean oil for the same period was 19 billion pounds (Ash 2013). RBD oil contains 

undetectable amounts of protein (Reeves and Weihrauch 1979) and linters are a highly 

processed product composed of nearly pure (i.e., >99.9%) cellulose (NCPA 2002; Nida, et al. 

1996). Food and food ingredients derived from cotton have been used safely for human food 

for more than 100 years in most cotton producing countries (NCPA 1993).

II.E.1.c. Pesticide Exposure

Pesticides have been used extensively in the production of cotton and soybeans (see Appendix

A of this Environmental Report). Consumers of cotton and soybean-derived food products 

may be exposed to residual levels of pesticides in those foods or from the consumption of 

animal-based food products containing residual levels of pesticides. Consumer exposure to 

pesticides used in cotton and soybean production may also potentially occur through ingestion 

of drinking water with residual levels of pesticides, and through contact with pesticides when 

applying them for residential purposes, such as through contact with lawns or other targets of 

consumer pesticide application (see Appendix E of this Environmental Report). 

The use of pesticides is regulated by EPA under the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA). The purpose of the Agency’s review is to ensure that the pesticide, 

“when used in accordance with widespread and commonly recognized practice,” will not cause 

“unreasonable adverse effects on the environment.” FIFRA 3(c)(5)(D). 
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If the pesticide may be used on food or feed crops, EPA ensures the safety of the food supply 

by establishing the amount of each pesticide that may safely remain in or on foods. These 

maximum pesticide residue levels (called “tolerances”) limit the amount of the pesticide residue 

that can legally remain in or on foods. EPA undertakes this analysis under the authority of the 

Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection 

Act of 1996 (FQPA), and must conclude that such tolerances will be safe, meaning that there is 

a reasonable certainty that no harm will result from aggregate (food, water and nonoccupational residential/recreational) exposure to the pesticide residues. (U.S. EPA 2013a). In 

addition, when multiple pesticides affect the same target organs through the same toxicological

mode- of-action, EPA considers the cumulative effect of those pesticides. In addition, the 

FDA and the USDA monitor foods for pesticide residues and work with the EPA to enforce 

these tolerances (USDA-AMS 2013).

The use of registered pesticides is further governed by labels, which are legally enforceable and 

define maximum application rates, total annual application limits, methods of application, and 

other use restrictions. The FIFRA registration process is discussed in more detail in Appendix 

E of this Environmental Report. 

To register a new pesticide product, EPA evaluates potential risks to humans and the 

environment, and typically requires applicants to submit more than 100 different scientific 

studies conducted according to EPA guidelines. The data required by EPA are used to evaluate 

whether a pesticide has the potential to cause adverse effects on humans (including acute, 

chronic, reproductive, and carcinogenic risk), wildlife, fish, and plants (including endangered 

species and other non-target organisms, i.e., organisms against which the pesticide is not 

intended to act). FIFRA was amended in 1988 to require the reregistration of products with 

active ingredients registered prior to November 1, 1984. In 1996, FIFRA was amended by the 

FQPA to require reevaluation of all pesticide active ingredient at fifteen year (or shorter) 

intervals thereafter (a process called Registration Review). The amendments called for the 

development and submission of data to support the continued registration of the active 

ingredient, as well as a review of all data submitted to the EPA. During the reregistration and 

registration review processes, EPA thoroughly reviews the scientific database since a pesticide’s 

original registration.

Dicamba: EPA has evaluated dicamba and has concluded that it has a complete and 

comprehensive regulatory database (toxicity, environmental fate, and ecological toxicity). EPA 

completed the reregistration process for dicamba and a Registration Eligibility Decision (RED) 

was issued in 2006 and subsequently amended in 2008 and 2009 (U.S. EPA 2009d). EPA 

concluded there is a reasonable certainty that no harm will result to the general population, or 

to infants and children, as a result of aggregate (combined) exposure to dicamba residues; and

that the available data submitted for dicamba are complete and adequate to support the 

continued registration of dicamba products and uses including current uses on commercial 

cotton and soybean. Part of EPA’s risk assessment included exposure to drinking water using a 

conservative modeled scenario that assumed that essentially all (87%) crop acres within the 

watershed were treated with dicamba (U.S. EPA 2009d; 2011b). 

Dicamba residue levels in soybean seed harvested from DT soybean treated with dicamba at 

more than twice the anticipated commercial in-crop application rate were less than 0.1 ppm, 

which is well below the established 10 ppm pesticide residue tolerance supporting dicamba use 
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on commercial soybean. Soybean forage and hay, which can be feed to livestock, have no 

established tolerance, for that reason Monsanto is also petitioning (Pesticide Petition # 

0F7725) the agency for the establishment of new tolerances on forage (45 ppm) and hay (70 

ppm). 

Dicamba residue levels in cottonseed harvested from DGT cotton treated with dicamba at the 

anticipated commercial in-crop application rate, and were 0.54 ppm, which is greater than the 

established 0.2 ppm pesticide residue tolerance supporting dicamba use on commercial cotton

(40 CFR § 180.227) which is for the combined residues of parent dicamba and its metabolite 5-

hydroxy dicamba. Cotton gin by-products, which serve as a ruminant feed supplement, have 

no established dicamba tolerance PP 2F8067 for the expanded use of dicamba on MON 

88701, an increase in the dicamba residue tolerance from 0.2 ppm to 3 ppm for cottonseed, the 

establishment of a tolerance of 70 ppm for cotton gin by-products, and the inclusion of DCSA 

in the residue definitions for cottonseed and gin by-products.

Glufosinate: The safety of glufosinate use on many crops, including cotton, was reviewed by the 

EPA as part of the food, feed, and environmental safety reassessment in 2000 (U.S. EPA 2003). 

In addition, glufosinate has been used for in-crop application in glufosinate-tolerant crops since 

1995 with no significant adverse effects reported. Glufosinate is currently labeled for in-crop 

application with glufosinate-tolerant cotton from emergence through early bloom growth stage. 

Currently glufosinate is undergoing Registration Review at EPA with a decision expected by the 

end of 2013 (U.S. EPA 2008b). It is expected that EPA will affirm the safety and efficacy of 

glufosinate and approve its continued use in the marketplace upon completion of the 

registration process.

The EPA-established glufosinate residue tolerances are 4.0 ppm and 15.0 ppm for cottonseed 

and gin by-products, respectively (40 CFR 180.473). Both of these tolerances include the 

combined residues of parent glufosinate and its metabolites N-acetyl glufosinate and 3-

methylphosphinico-propionic acid.

II.E.2. Worker Health

Agriculture is a relatively hazardous industry, with machinery-related injuries – often from 

tilling equipment – as the primary hazard. Other fairly common hazards in agriculture include 

injuries related to animal contact, motor vehicles, and falls (CDC 2010). 

Pesticides have been used extensively in cotton and soybean production; see Appendix A for 

details on current pesticide use. In the agricultural production of soybeans and cotton, growers 

and workers may be exposed to pesticides applied to soybeans and cotton by mixing, loading, 

or applying chemicals, or by entering a previously treated site. EPA conducts a comprehensive 

occupational worker safety evaluation and risk assessment of pesticides to assess the risk to 

agricultural workers during mixing, loading, and applying. See Appendix E for additional 

information on worker health characteristics of current cotton and soybean herbicides.

Dicamba: EPA evaluated occupational risk to workers as a part of the dicamba RED and 

concluded that worker exposure to dicamba for all registered agricultural uses – including 

exposures associated with current cotton and soybean uses – meet the “no unreasonable 

adverse effects” criteria of FIFRA (U.S. EPA 2009d). 
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Glufosinate: EPA evaluated risk to workers as a part of the food, feed, and environmental safety 

reassessment of glufosinate in 2000 (U.S. EPA 2003) and EPA is expected to provide a 

Registration Review by the end of 2013. In addition, glufosinate is currently labeled for in-crop 

application with glufosinate-tolerant cotton from emergence through early bloom growth stage.

In addition, the Worker Protection Standard (WPS) provides additional regulatory protections 

to agricultural workers and pesticide applicators.43 The WPS contains requirements for 

pesticide safety training, notification of pesticide applications, use of personal protective 

equipment (PPE), restricted-entry intervals (REI) after pesticide application, decontamination 

supplies, and emergency medical assistance. Under the WPS, EPA requires the pesticide label 

to specify PPE and REI that will provide an appropriate level of protection, based on the 

properties of the pesticide product. 

II.E.2.a. Soybean

The grain handling and processing operations are a highly hazardous work environment. 

Workers can be exposed to a number of serious hazards including fires and explosions from 

dust accumulation, suffocation from entrapment, falls, and crushing/amputating injuries. 

OSHA has developed specific guidance for grain processors and handlers to reduce these risks 

to workers (OSHA 2013). No unique soybean-specific worker hazards currently exist.

II.E.2.b. Cotton

A worker health hazard specific to cotton production is the cotton dust generated during 

cotton handing and processing, which has been identified as a chemical hazard by the National 

Institute for Occupational Safety and Health (NIOSH) (CDC 2013). The inhalation of cotton 

dust by mill workers can lead to asthma-like conditions called byssinosis (Salvaggio, et al. 1986). 

Adverse health effects, such as ergonomic injuries, may potentially occur as a result of handweeding due to the repetitive nature and prolonged exertions of the hands (OSHA 2013). In 

some cases, farmers have had to resort to hand-weeding in order to achieve satisfactory control 

of Palmer amaranth. Georgia cotton growers have increased hand-weeding on 17% of the 

acreage in 2000-2005 to 52% of the acreage in 2006-2010 (Sosnoskie and Culpepper 2012). 

Similarly, in 2010, at least 20% of the cotton acres in Tennessee were hand-weeded (Culpepper 

et al. 2011).

II.F. ANIMAL HEALTH

II.F.1. Animal Feed: Soybean

Soybean meal is the most valuable component obtained from processing soybean, accounting 

for roughly 50-75% of its overall value (USDA-ERS 2005). Soybean meal is a substantial part 

of animal feed rations in the United States. Animal agriculture consumes 98% of the U.S. 

 

43 40 CFR 170, http://www.epa.gov/pesticides/safety/workers/PART170.htm
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soybean meal produced (Soyatech 2013) and 70% of soybeans worldwide (USB 2011b). In 

2011, approximately 39 million tons of soybean meal were produced, 27.3 million tons of which 

were marketed for animal feed, with the largest volumes consumed by poultry (48 percent), 

swine (26 percent), and beef (12 percent) (ASA 2012). Soybean meal can serve as an excellent 

protein source that can complement the limited amino acid profile of feeds derived from corn 

(Kerley and Allee 2003). 

Dairy and livestock producers also use soybean forage as feed. Soybean forage is an 

inexpensive, readily available, on-farm source of high-quality, high-protein forage adapted to 

growth during the summer months when other forage legume species typically are restricted in 

growth (USDA-ARS, 2006). Soybean forage can be used as hay or to produce silage (MAFRI, 

2004). An additional use of soybean for feed can be full-fat (whole) soybean for dairy cattle 

and swine, but for swine it is limited to a maximum of 20% of the total diet due to the high oil 

content (Yacentiuk, 2008). 

II.F.2. Animal Feed: Cotton

Seed residue remaining after fiber removal for textile production (cottonseed meal and hulls) is 

marketed as cottonseed meal, cottonseed hulls, and whole cottonseed and utilized in the animal 

feed industry as sources of protein, fiber and energy (NCPA 2002; OECD 2009). The value of 

cottonseed as animal feed represents a substantial portion of the grower’s income from cotton 

(Blasi and Drouillard 2002).

Cottonseed meal, which makes up over a third of the value of cottonseed, is an excellent source 

of protein for ruminant animals and is widely used in animal feed (Blasi and Drouillard 2002; 

Calhoun 2011). As mentioned in Section II.E.1.b, cottonseed contains the anti-nutrients 

gossypol and cyclopropenoid fatty acids. Gossypol helps protect the cotton plant from 

pathogens, but is an anti-nutrient for which sensitivity is species-dependent. Gossypol is also 

toxic to some species (Gadberry 2011). 

Cottonseed is typically fed to ruminants (i.e., cattle), because they have a relatively low 

sensitivity to gossypol and can tolerate moderate gossypol inclusion in their diets. Highly 

processed cottonseed meal is also fed to non-ruminant farm animals in limited quantities 

(OECD 2009). Cyclopropenoid fatty acids interfere with the metabolism of saturated fats (Cao, 

et al. 1993; Rolph, et al. 1990) and reportedly have adverse effects on egg yolk discoloration and 

reduced hatchability in chickens (Lordelo, et al. 2007; OECD 2004; 2008). 

The hull is the tough, protective covering of the cottonseed that is removed prior to processing 

the seed for oil and meal. It is used as feed for livestock and can be an economical roughage 

that provides fiber, as well as serving as a good carrier for cottonseed meal and grain (NCPA 

2002). Gin by-products, the dried plant material cleaned from the fiber during ginning, is also 

used as a source of roughage for livestock feeds.

Cottonseed is an animal food source most commonly in the form of cottonseed meal. NonGE cotton varieties, both those developed for conventional use and for use in organic 

production systems, are not routinely required to be evaluated by any regulatory agency in the 

U.S. for feed safety prior to release in the market. 
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II.F.3. FDA Consultation Process

Under the FFDCA, it is the responsibility of feed manufacturers to ensure that the products 

they market are safe and properly labeled. Feed derived from GE soybean and cotton must 

comply with all applicable legal and regulatory requirements, which are designed to protect 

human health. GE crops used for food or feed purposes undergo a voluntary consultation 

process with the FDA prior to release onto the market (U.S. FDA 2001b). Although this 

consultation is a voluntary process, thus far developers who intend to commercialize a GE crop 

that will be used for food or feed have completed a consultation with the FDA. In a 

consultation, a developer who intends to commercialize a GE crop meets with the agency to 

identify and discuss relevant safety, nutritional, or other regulatory issues regarding the food 

and feed derived from that crop. The developer then submits to FDA a scientific and 

regulatory assessment summary of the food and feed safety of the product. FDA evaluates the 

submission and responds to the developer by letter (U.S. FDA 2010).

II.F.3.a. FDA Consultation Process: Soybean

Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DT soybean on October 11, 2011 (BNF 

No. 00125, Monsanto, 2011). As a part of its evaluation, FDA reviewed information on the 

identity, function, and characterization of the genes, including expression of the gene products 

in DT soybean , as well as information on the safety of the MON 87708 DMO and DT 

soybean including a dietary risk assessment. 

II.F.3.b. FDA Consultation Process: Cotton

Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DGT Cotton on April 24, 2013 (FDA 

2013). As a part of its evaluation, FDA reviewed information on the identity, function, and 

characterization of the genes, including expression of the gene products in DGT cotton, as well 

as information on the safety of DGT Cotton including a dietary risk assessment. 

II.F.4. EPA Dicamba Tolerance Assessment

As discussed elsewhere in this report, Congress transferred regulatory authority over pesticides 

from USDA to EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or 

herbicide resistance, and no authority to consider herbicide impacts under the PPA. 

EPA has responsibility to regulate the use of pesticides (including herbicides) that may be used 

on feed crops, and must establish pesticide tolerances (maximum pesticide residue levels) for 

the amount of pesticide residue that can legally remain in or on the feed crop. EPA undertakes 

this analysis under the authority of the Federal Food, Drug, and Cosmetic Act (FFDCA), and 

must conclude that such tolerances will be safe, meaning that there is a “reasonable certainty 

that no harm” to human health will result from the use of the pesticide. This finding of 

reasonable certainty of no harm is obligated under the FFDCA, as amended by the FQPA of 

1996. Similar to the establishment of pesticide tolerances for food, the EPA will consider the 

toxicity of the pesticide and its break-down products, pesticide use rate and frequency of 
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application; and how much of the pesticide (i.e., the residue) remains in or on food by the time 

is it marketed and prepared in its establishment of tolerance for animal feed (U.S. EPA 2013a).

DT Soybean: EPA reassessed all dicamba pesticide food and feed tolerances as part of the 

dicamba RED, including the 10 ppm soybean seed tolerance supporting the existing use in 

conventional soybean (U.S. EPA 2009d). A complete listing of dicamba feed tolerances can be 

found at 40 CFR § 180.227. Monsanto has requested a registration of an expanded use of a 

low-volatility DGA dicamba formulation on DT soybean, and petitioned (Pesticide Petition # 

0F7725) the EPA to establish new feed tolerances on soybean forage (45 ppm) and soybean hay 

(70 ppm). Tolerances for soybean forage and hay for current dicamba uses in conventional 

soybean were not previously established because the current preharvest application is made past 

the stage where the crop would be useful as forage or hay. No other revisions to dicamba 

pesticide residue tolerances are needed including animal products such as meat or milk. 

DGT cotton: Monsanto has requested a registration from U.S. EPA for the expanded use of a 

low-volatility DGA dicamba formulation on DGT cotton, an increase in the dicamba residue 

tolerance from 0.2 ppm to 3 ppm for cottonseed, the establishment of a tolerance of 70 ppm 

for cotton gin by-products, and the inclusion of DCSA in the residue definitions for cottonseed 

and gin by-products. No other revisions to dicamba pesticide residue tolerances are needed 

including animal products such as meat or milk. 

II.G. SOCIOECONOMICS

This section addresses: (1) the domestic economic environment of soybean and cotton; (2) the 

trade economic environments of soybean and cotton; and (3) public perceptions regarding 

genetically modified ingredients in food.

The economics of cotton and soybean are presented below, divided into discussion of: (1) 

soybean market overview; (2) soybean production costs and revenue, including a discussion of 

the impacts of genetically-engineered (GE) soybean; (3) U.S. cotton market overview; (4) 

cotton production costs and revenue, including a discussion of GE cotton production; and (5) 

the organic market segments. 

II.G.1. Domestic Economic Environments of Soybean and Cotton

II.G.1.a. Domestic Economic Environment: Soybean

In 2012, 77 million acres of soybeans were cultivated in the United States (USDA-NASS 

2012e), yielding approximately 3.0 billion bushels at a value of 43.2 billion U.S. 

dollars0020(USDA-NASS 2013a). Total 2012 U.S. inventory (2011 remaining stocks plus 2012 

production) totaled 3.2 billion bushels, with 43 percent of U.S. soybean destined for the export 

market (Ash 2013). The remaining 57 percent of U.S. soybean inventory was primarily utilized 

to produce soybean meal intended for feed, with lesser amounts processed for soybean oil 

intended for industrial or consumption purposes; seed and residuals; or ending stock for 

storage. The majority of domestic soybean use in the United States is used for animal feed or 

secondary industrial products, with only a small proportion of the soybean crop being 

consumed directly by humans.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 108 of 946

Almost all of the U.S. soybean supply (95.6% in 2009/10) comes from domestic production 

and almost all of this supply (96.8%) is either exported or crushed for meal and oil (Table II.G1). In any given year, the resulting meal and oil is modestly supplemented with carryover stocks 

and imports before being consumed domestically or exported. In the U.S., almost all of the 

soybean meal is used for animal feed (97.5% in 2002/03) (SMIC 2006). The vast majority of 

the oil (86% in 2010) is used for human consumption, with the balance going to industrial 

products (Figure II.G-1). Soybean oil represents almost 70% of the oils consumed by U.S. 

households. It is notable that higher petroleum prices and an increased interest in biofuels are 

increasing the demand for soybean-based biodiesel. From 1999 to 2009, the consumption of 

soybean biodiesel has increased from 0.5 to 545 million gallons (Soy Stats 2010).

The top ten soybean producing states (Iowa, Illinois, Minnesota, Indiana, Nebraska, Ohio, 

Missouri, South Dakota, Kansas, and North Dakota) accounted for more than 80% of this 

production (Table II.G-2). These states are located in the USDA-ERS’s Heartland (Iowa, 

Illinois, Indiana, Minnesota, Missouri, Nebraska, Ohio, and South Dakota), Northern Crescent 

(Minnesota and Ohio), Northern Great Plains (Nebraska, Minnesota, North Dakota, and South 

Dakota), Prairie Gateway (Kansas and Nebraska), and Eastern Uplands (Missouri and Ohio) 

resource regions (Fernandez-Cornejo and McBride 2002), which vary in terms of land 

productivity and cost of production (Figure II.G-2). The most productive of these regions are 

the Heartland and Northern Crescent. While these regions have higher production cost, their 

higher productivity still results in greater profitability. In 2010, the U.S. total gross average value 

of soybean production per planted acre was $449.32 and the average price of a bushel of 

soybeans at harvest was $9.56 (USDA-ERS 2012b).

The domestic soybean industry is primarily composed of commodity production businesses and 

the users of soybean products (Figure II.G-3). Ultimately, the profitability of a soybean field is 

dependent on the suitability of a soybean harvest for its target market and the production costs 

for that particular harvest. 

Because domestic utilization of soybean is focused on animal feed and oil production, the 

chemical composition of a soybean at harvest is important. Soy meal typically contains about 

50 percent protein by dry weight, and is the most important product of soybean production. 

Of the domestically crushed soybean, 53 percent of soybean by weight produces meal and 19 

percent produces oil (USB, 2011a). Changes in the fatty acid profile may impact food and 

industrial uses of the soybean oil. Fatty acid composition of the soybean oil affects melting 

point, oxidative stability, and chemical functionality, and changes in any of these can impact the 

market sector of the product (APAG, 2011). These fatty acid properties influence the market 

applications for the oil, and various foods and industrial products are formulated to take these 

properties into consideration (Cahoon 2003; Cargill 2011; USB 2011a)
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Table II.G-1. U.S. soybean supply and disappearance12009/10.

Soybeans Soybean Meal

(Million Metric Tons)

Soybean Oil

Total 95.58 38.19 10.24

-------------------------------------Supply--------------------------------------

Beginning Stocks 3.76 0.21 1.3

Production 91.42 37.83 8.90

Imports 0,40 0.15 0.05

---------------------------------Disappearance--------------------------------

Crush 47.67 --

2

--

Feed, Seed & Residual 2.95 -- --

Domestic -- 27.78 7.20

Exports 40.85 10.14 7.54

Ending Stocks 4.11 0.27 1.53

Source: USDA-ERS (USDA-ERS 2011e)

1Disappearance is the consumed supply

2 No data
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Figure II.G-1. Distribution of U.S. Soybean Oil Consumption in 2010.

Source: (ASA 2011)

58% 23%

14%

5%

Salad or Cooking Oil Baking & Frying Fats

Industrial Products Other Edible Products
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Table II.G-2. Soybean crop value by state1.

State Crop Value 

($ millions)

Percent of Total

Soybean Crop Value

2008 2009 2010 2008 2009 2010

Alabama 126 172 100 0.4 0.5 0.3

Arkansas 1,191 1,185 1,246 4.0 3.7 3.2

Delaware 50 74 66 0.2 0.2 0.2

Florida 9 12 8 0.03 0.04 0.02

Georgia 122 155 76 0.4 0.5 0.2

Illinois 4,372 4,215 5,779 14.8 13.1 14.9

Indiana 2,492 2,612 3,050 8.5 8.1 7.8

Iowa 4,586 4,627 5,806 15.6 14.4 14.9

Kansas 1,129 1,506 1,658 3.8 4.7 4.3

Kentucky 476 675 572 1.6 2.1 1.5

Louisiana 298 354 456 1.0 1.1 1.2

Maryland 134 190 188 0.5 0.6 0.5

Michigan 687 759 1,012 2.3 2.4 2.6

Minnesota 2,675 2,674 3,717 9.1 8.3 9.6

Mississippi 728 713 846 2.5 2.2 2.2

Missouri 1,862 2,216 2,546 6.3 6.9 6.5

Nebraska 2,212 2,459 3,026 7.5 7.7 7.8

New Jersey 26 34 25 0.1 0.1 0.1

New York 107 99 147 0.4 0.3 0.4

North Carolina 514 571 496 1.7 1.8 1.3

North Dakota 1,022 1,075 1,564 3.5 3.3 4.0

1

(USDA-NASS 2011a)
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Figure II.G-2. Planted Soybean Acreage by County in the U.S. in 20121

1

Source is USDA-NASS (2012f).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 113 of 946

Figure II.G-3. General flow of U.S. soybean commodities.

Size of directional arrows is approximately proportional to use. For example, bold arrows represent 

the primary path of soybean commodities, whereas dashed arrows represent paths of soybean use 

that are relatively minor. Businesses are boxed in gray, while commodities are unboxed.

Seed

Agrichem

ical Retailers Growers Grain

Elevators

Soybean 

purchasers/

crushers

Soybean oil refining

and processing

Industrial oil

producers

Consumable

oil producers

Animal feed 

producers

Animal

feed

Consumable 

oil products

Industrial 

oil products

Animal

feed In-house

processing

Soybean

meal

Soybean

oil

Consumable soybean

products Exports

Primary 

Users

Commodity 

Production

Secondary 

Users

Out-of-house

processing

+
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II.G.1.a.(1) Soybean Production Costs and Revenue

Managing input costs is a major component to the economics of producing a soybean crop (Helsel 

and Minor 1993). Key decisions on input costs include choosing what soybean varieties to plant, 

amounts of fertilizer to apply, and what herbicide program to use. 

Production cost data are provided by USDA-ERS and collected in surveys conducted every four to 

eight years for each commodity as part of the annual ARMS (USDA-ERS 2011c). In general, 

operating costs represented 26% ($137/acre) of soybean farm gross income and may include 

expenses related to seed purchases, agronomic inputs (e.g., fertilizers, irrigation, and pesticides), and 

the maintenance of farm equipment. Allocated overhead costs, on the other hand, represented 

approximately 49% ($260/acre) of soybean farm gross income and include expenses related to labor, 

acquisition of farming equipment, land rental rates, taxes, and insurance premiums (USDA-ERS 

2011c). 

Gross value of production on a typical U.S. soybean farm in 2011 was approximately $525/acre 

(Table II.G-3). In total, net profit of a typical U.S. soybean farm, minus operating and overhead 

costs, was $129/acre in 2011 (USDA-ERS 2011c). 
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Table II.G-3. Soybean commodity costs and returns, 2011.

Soybean Cost/Return per Planted Acre

($ USD)

Gross value of production

Primary Product 525.36

Total, gross value of production 525.36

Operating costs:

Seed 55.55

Fertilizer 22.84

Chemicals 16.42

Custom operations 7.18

Fuel, lube, and electricity 20.98

Repairs 13.68

Purchased irrigation water 0.15

Interest on operating capital 0.07

Total, operating costs 136.87

Allocated overhead

Hired labor 2.07

Opportunity cost of unpaid labor 17.09

Capital recovery of machinery and equipment 81.34

Taxes and insurance 134.30

General farm overhead 9.93

Total, allocated overhead 15.10

Total costs listed 259.83

Value of production less total costs listed 128.66

Value of production less operating costs 388.49

Source: USDA-ERS (2012c)

Soybean production practices and economic related to weed control have changed over the past 

fifteen years following the commercial release of Roundup Ready® soybean varieties in 1996 and 

LibertyLink® soybean varieties in 2009. Roundup Ready® soybeans are genetically engineered to 

be tolerant to glyphosate, while LibertyLink® soybeans are engineered to be tolerant to glufosinate. 

GE soybeans were planted on 94% of U.S. soybean acreage in 2011 (see Table II.G-4). In terms of 

weed control costs, Johnson et al. (2008) estimated a $1.562 billion reduction in production costs 

associated with grower’s adoption of herbicide-tolerant soybeans in 2006. A more recent study 

found a $17.75 net cost saving per U.S. GE soybean acre in 2008 (Brookes and Barfoot 2012).

As of the 2010 growing season, there were 10 different weed species with glyphosate-resistant 

populations ranging across 25 different U.S. states (Table II.G-5) (Heap 2011). Resistant weed 

populations have been found in all but 1 (South Dakota) of the 10 major soybean producing states. 

Surveys show that farmers expect glyphosate resistance will or has increased the cost of weed 

control from $10.87 to $16.30 per acre (Foresman and Glasgow 2008; Hurley, et al. 2009b), and that 

farmers prefer to address the problem by using additional herbicides with different modes of action 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 116 of 946

(Foresman and Glasgow 2008; Johnson and Gibson 2006; Johnson, et al. 2009; Scott and VanGessel 

2007).

In response to the increased incidence of glyphosate-resistant weeds, herbicide manufacturers and 

distributors offer incentive programs and promote diversified weed management practices. One 

example of such a program is the Roundup Ready PLUS TM program that builds on the continued 

benefits of the Roundup Ready weed management system with glyphosate-based agricultural 

herbicides, but also promotes and incentives the use of additional registered herbicides to target hard 

to control and glyphosate-resistant weeds in soybean and cotton. The Roundup Ready PLUS 

program was developed by Monsanto in conjunction with academics and industry partners to help 

farmers improve their weed control. Herbicide providers included in the Roundup Ready PLUS 

program are Monsanto, Valent, Syngenta, FMC Agricultural Products, AMVAC Chemical 

Corporation and Makhteshim Agan of North America, Inc. 

(www.roundupreadyplus.com/Pages/Home.aspx)

There is consistent evidence that farmers obtain substantial financial and non-financial benefits as a 

result of adoption of GE crops. These benefits include an opportunity to increase income from offfarm labor; increased flexibility and simplicity in the application of pesticides; an ability to adopt 

more environmentally friendly farming practices; increased consistency of weed control; increased 

human safety; equipment savings; and labor savings (Duke and Powles 2009; Fernandez-Cornejo, et 

al. 2005; Fernandez-Cornejo and McBride 2002; Fernandez-Cornejo and W.D. McBride 2000; 

Hurley, et al. 2009a; Marra, et al. 2004).
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Table II.G-4. Percentage of soybean acreage planted with GE herbicide-tolerant soybean 

varieties by state and for the U.S.

State 200

0

200

1

200

2

200

3

200

4

200

5

200

6

200

7

200

8

200

9

201

0

201

1

Arkansas 43 60 68 84 92 92 92 92 94 94 96 95

Illinois 44 64 71 77 81 81 87 88 87 90 89 92

Indiana 63 78 83 88 87 89 92 94 96 94 95 96

Iowa 59 73 75 84 89 91 91 94 95 94 96 97

Kansas 66 80 83 87 87 90 85 92 95 94 95 96

Michigan 50 59 72 73 75 76 81 87 84 83 85 91

Minnesota 46 63 71 79 82 83 88 92 91 92 93 95

Mississippi 48 63 80 89 93 96 96 96 97 94 98 98

Missouri 62 69 72 83 87 89 93 91 92 89 94 91

Nebraska 72 76 85 86 92 91 90 96 97 96 94 97

North 

Dakota 22 49 61 74 82 89 90 92 94 94 94 94

Ohio 48 64 73 74 76 77 82 87 89 83 86 85

South 

Dakota 68 80 89 91 95 95 93 97 97 98 98 98

Wisconsin 51 63 78 84 82 84 85 88 90 85 88 91

Other1

States 54 64 70 76 82 84 86 86 87 87 90 92

U.S. 54 68 75 81 85 87 89 91 92 91 93 94

Source: USDA-ERS (2011a)

1

Includes all other states in the soybean estimating program.
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Table II.G-5. Common U.S. Glyphosate-Resistant Weeds1

Genus and Species (Common Name) 1

st Report

Country (Year) U.S. Occurrence (Year Reported)

Glycine (G/9) Resistant (i.e., glyphosate and sulfosate)

Amaranthus palmeri (Palmer Amaranth) U.S. (2005)

Georgia & North Carolina (2005)

Arkansas & Tennessee (2006)

New Mexico (2007)

Mississippi & Missouri (2008)

Louisiana (2010)

Amaranthus tuberculatus 

(Common Waterhemp) U.S. (2005)

Missouri (2005)

Illinois & Kansas (2006)

Minnesota (2007)

Indiana & Iowa (2009)

Mississippi (2010)

Ambrosia artemisiifolia (Common Ragweed) U.S. (2004)

Arkansas & Missouri (2004)

Ohio (2006)

Indiana, Kansas & North Dakota (2007)

Minnesota (2008)

Ambrosia trifida (Giant Ragweed) U.S. (2004)

Ohio (2004)

Arkansas & Indiana (2005)

Kansas & Minnesota (2006)

Tennessee (2007)

Iowa & Missouri (2009)

Mississippi 2010)

Conyza canadensis (Horseweed) U.S. (2000)

Delaware (2000)

Kentucky & Tennessee (2001)

Indiana, Maryland, Missouri, New Jersey & Ohio (2002)

Arkansas, Mississippi, North Carolina & Pennsylvania 

(2003)

California, Illinois & Kansas (2005)

Nebraska (2006) Michigan (2007) Oklahoma (2009)

1 Heap, 2011
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 119 of 946

II.G.1.b.

II.G.1.b.(1) Organic Soybean Production

Organic soybean was produced on 96,080 acres in 2011 and yielded 2.9 million bushels, equal to 

approximately 0.09% of U.S. soybean production (USDA-NASS 2012a). The average yield was 30 

bushels per acre. Major production states are Iowa, Minnesota, Michigan, New York, Illinois, 

Nebraska, and Wisconsin (USDA-NASS 2012d). Organic soybean production acreage has ranged 

from 96,080 to 136,000 acres since 2000 (USDA-ERS 2010d). Organic farming operations as 

described by the National Organic Program, which is administered by USDA’s Agricultural 

Marketing Service (AMS), requires organic production operations to have distinct, defined 

boundaries and buffer zones to prevent unintended contact with prohibited substances or products 

of excluded methods from adjoining land that is not under an organic production management plan. 

Organic production operations must also develop and maintain an organic production system plan 

approved by an accredited certifying agent. This plan enables the production operation to achieve 

and document compliance with the National Organic Standards, including the prohibition of the use 

of excluded methods. Excluded methods include a variety of methods used to genetically engineer 

organisms or influence their growth and development by means that are not possible under natural 

conditions or processes. The use of biotechnology such as that used to produce MON 87708 is an 

excluded method under the National Organic Program. 

Organic certification involves oversight by an accredited certifying agent of the materials and 

practices used to produce or handle an organic agricultural product. This oversight includes an 

annual review of the certified operation’s organic system plan and on-site inspections of the certified 

operation and its records. Although the National Organic Standards prohibit the use of excluded 

methods, they do not require testing of inputs or products for the presence of excluded methods. 

The presence of a detectable residue of a product of excluded methods alone does not necessarily 

constitute a violation of the National Organic Standards (USDA-AMS 2010). The unintentional 

presence of the products of excluded methods will not affect the status of an organic product or 

operation when the operation has not used excluded methods and has taken reasonable steps to 

avoid contact with the products of excluded methods as detailed in an approved organic system 

plan. Organic certification indicates that organic production and handling processes have been 

followed, not that the product itself is “free” from any particular substance. 

Organic soybean producers use production practices designed to prevent commingling of their crop 

with neighboring crops treated with herbicides and other pesticides (spray drift), or that may be 

using plant varieties produced by excluded methods (pollen movement). These well established 

practices include isolation zones, use of buffer rows surrounding the organic crop, adjusted planting 

dates, and varietal selection. The implementation of management practices to avoid pollen from a 

biotechnology-derived crop in organic or conventional soybean production operations is facilitated 

by the nature of soybean pollination. Soybean is a highly self-pollinated species and exhibits a very 

low level of outcrossing (see Section IX.D). Outcrossing is the genetic transmission of a defined 

heritable characteristic from one group of individuals (population, crop variety) to another. 

Outcrossing most commonly results from cross-pollination. Since soybean is highly self-pollinating, 

organic or conventional soybean producers can and have effectively implemented practices (e.g., 

isolation during the growing season, equipment cleaning during harvest, and post-harvest separation 

of harvested seed) that allow them to reasonably avoid biotechnology-derived soybean and maintain 

organic or conventional production status (Brookes 2004). Information about the National Organic 

Program, organic standards, and practices can be viewed on line (USDA-AMS 2010).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 120 of 946

II.G.1.c. Domestic Economic Environment: Cotton

In 2010/2011, most of the world’s cotton production (116.40 million bales annually) was grown in 

China (30.5 million bales), India (26.4 million bales), the United States (18.1 million bales), Pakistan 

(8.6 million bales) and Brazil (9.0 million). In 2010/2011, the U.S. supplied over 14 million bales of 

the world’s cotton exports, accounting for approximately 40% of the total world export market for 

cotton (USDA-FAS 2011b). China, Bangladesh, Indonesia, and Turkey are major importers of 

cotton. The largest customers for U.S. cotton are Asian countries and Mexico, due to the 

prevalence of textile manufacturing (NCCA 2010a; b). Cottonseed production currently results in 

approximately 10% of the world’s oilseed production (USDA-FAS 2011a), and is exceeded by 

soybean (58%) and rapeseed (13%).

Gossypium hirsutum (upland cotton) cultivars account for more than 90% of the world’s annual cotton 

crop and 97% of the U.S. cotton production (Smith and Cothren 1999; USDA-NASS 2012c). G. 

barbadense, known as extra-long staple, Pima, or Egyptian cotton, is also grown in the U.S, and 

accounts for approximately 3% of U.S. acreage (USDA-NASS 2012c). The long, strong, fine fibers 

produced by Pima are ideal for specialized uses, but due to the geographic limitation for optimum 

production in the U.S., it is economically less viable than the G. hirsutum cultivars. Pima cotton 

requires a longer growing season than upland cotton, and production is limited to the Southwestern 

states.

Cotton is a crop that produces two commodities: fiber and seed. The modern cotton gin has 

enhanced the value of cotton commodities by separating the fiber from the seed and by removing 

foreign matter, while preserving the inherent qualities of the fiber and seed (Smith and Cothren 

1999). The fiber is the more valuable product of the crop, normally accounting for approximately 

85% of the value of the harvested cotton. For every 100 pounds of fiber produced by the cotton 

plant, it also produces about 162 pounds of cottonseed (NCCA 2010a; b). Approximately one-third 

of the cottonseed is crushed for oil and meal used in both food products and in livestock feed. The 

oil is the most valuable by-product of cottonseed (NCCA 2010a). The extracted oil from cottonseed 

is further processed to produce cooking oil, salad dressing, shortening, and margarine. Limited

quantities of the oil are used in soaps, pharmaceuticals, cosmetics, textile finishes, and other 

products.

II.G.1.c.(1) Cotton Production Costs and Revenue

The value of cotton production reached $7.27 billion in the U.S. in 2011 (USDA-NASS 2012a). In 

comparison, corn and soybean production values in 2011 were $76.46 and $35.78 billion, 

respectively (USDA-NASS 2012a).

The average operating cost for producing cotton in the U.S. was $465 per planted acre in 2011. The 

return or the value of the production less operating cost was reported to be $123 per planted acre in 

2011 (USDA-ERS 2012e). The fluctuation in cotton price is the main factor contributing to the 

variation in value of cotton production from year to year. See Table II.G-6. These production 

returns for cotton do not include revenue from government program payments, which would 

significantly improve the return values presented for cotton. Comparable operating costs for 

producing corn and soybean in 2011 were $332 and $137 per acre, respectfully (USDA-ERS 2012d; 

b). Comparable returns for producing corn and soybean were $505 and $388 per acre, respectively.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 121 of 946

Revenue, cost, and returns vary among cotton growing regions (Table II.G-7). The cotton growing 

area in Missouri (“Heartland”) had the highest 2011 return per acre with $397. This region also had 

one of the highest average cotton and cottonseed yields (941 and 1522 pounds/planted acre, 

respectively). Operating costs were the highest in the Fruitful Rim region primarily due to the 

higher ginning costs. In the Prairie Gateway region, which is the largest cotton growing region 

(Kansas, New Mexico, Oklahoma, and Northern Texas), the returns on cotton were -$61 per acre in 

2011. The negative returns in the Prairie Gateway region are the result of the severe drought 

conditions in Texas, which caused many growers not to harvest their fields.

In the Southeast, many farmers have implemented additional manual labor, such as hand-weeding, in 

order to achieve satisfactory control of Palmer amaranth. Georgia cotton growers have increased 

hand-weeding from 17% of the state cotton acreage in 2000-2005 to 52% of the acreage in 2006-

2010. Hand-weeding has a current cost of $23 per acre (Sosnoskie and Culpepper 2012). A survey 

of Georgia cotton growers conducted in 2010 found that 92% of growers spent $16 million on 

hand-weeding 53% of the total Georgia cotton crop. Similarly, at least 20% of the cotton acres in 

Tennessee were hand-weeded at cost of more than $3 million. 

The cotton industry continues to face many of the supply and demand concerns confronting other 

field crops. However, because cotton is used primarily in manufactured products, such as clothing 

and home furnishings, the industry faces additional challenges associated with the economic wellbeing of downstream manufacturing industries, as well as the general economic well-being of the 

final consumer (USDA-ERS 2009).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 122 of 946

Table II.G-6. U.S. Cotton Production Costs and Returns From 2006 to 20111

Cotton Cost/Return per Planted Acre

($ USD)

Production Cost or Return Category/ 

Itemized Costs 2006 2007 2008 2009 2010 2011

Gross Value of Production (cotton and 

cottonseed) 384.61 637.2 491.78 444.28 740.82 588.01

Operating Costs:

Seed 61.69 60.34 64.78 73.17 80.98 96.61

Fertilizer2 44.55 62.81 98.25 90.77 72.86 95.06

Chemicals 62.99 63.35 62.68 67.93 67.12 66.72

Ginning 91.65 137.17 96.24 99.30 129.88 80.85

Other3 95.58 113.19 121.68 99.89 113.06 125.79

Total, operating costs 356.46 436.9 443.63 431.06 463.90 465.03

Allocated overhead4 198.61 229.5 244.57 259.43 269.34 283.82

Total cost listed 555.07 666.4 688.2 690.5 733.24 748.85

Value of production less total cost listed -170.5 -29.2 -196.4 -246.2 7.58 -160.8

Value of production less operating costs 28.15 200.3 48.15 13.22 276.92 122.98

Supporting Information:

Cotton yield: lbs/planted acre 686 911 632 618 780 496

Price: $/pound 0.47 0.57 0.6 0.59 0.82 0.96

Cottonseed yield: lbs./planted acre 1,113 1,474 1,023 999 1,262 802

Price: $/pound 0.06 0.08 0.11 0.08 0.08 0.14

Enterprise size (planted acres) 740 687 687 687 687 687

Production Practices:

Irrigated (%) 31 43 43 43 43 43

Dryland (%) 69 57 57 57 57 57

1

(USDA-ERS 2012f)

2Commercial fertilizer, soil conditioners, and manure.

3Custom operations, fuel, lube, electricity, repairs, purchased irrigation water, and interest on 

operating costs.

4Hired labor, opportunity cost of unpaid labor, capital recovery of machinery and equipment, 

opportunity cost of land, taxes and insurance and general farm overhead.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 123 of 946

Table II.G-7. Regional U.S. Cotton Production Costs and Returns in 20111

Cotton Cost/Return per Planted Acre

($ USD)

Production Cost or Return 

Category/ Itemized Costs Heartland

Prairie 

Gateway

Southern 

Seaboard

Fruitful 

Rim

Mississippi 

Portal

Gross Value of Production 

(cotton and cottonseed) 1,062.10 266.40 776.23 1,074.31 982.26

Operating Costs:

Seed 159.42 74.72 108.38 99.98 135.96

Fertilizer2 119.06 54.67 147.84 123.74 126.38

Chemicals 87.03 41.14 88.13 95.41 101.85

Ginning 149.58 38.21 101.04 137.56 143.55

Other3 126.02 110.75 112.92 259.09 121.86

Total, operating costs 641.11 319.49 558.31 715.78 629.60

Allocated overhead4 375.44 235.46 296.37 393.22 348.02

Total cost listed 1,016.55 554.46 854.68 1,109.00 977.62

Value of production less total 

cost listed 45.55 -288.55 -78.45 -34.69 4.64

Value of production less 

operating costs 420.99 -53.09 217.92 358.53 352.66

Supporting Information:

Cotton yield: lbs/planted acre 948 224 711 671 869

Price: $/pound 0.91 0.93 0.93 1.31 0.92

Cottonseed yield: lbs./planted 

acre

1,534 363 1,150 1,085 1,406

Price: $/pound 0.13 0.16 0.10 0.18 0.13

Enterprise size (planted acres) 861 770 453 507 954

Production Practices:

Irrigated (%) 61 46 28 57 45

Dryland (%) 39 54 72 43 55

1 (USDA-ERS 2012e). Production regions are Farm Resource Regions defined by USDA-ERS. Heartland region includes MO 

cotton; Prairie Gateway includes KS, NM, OK, and Northern TX cotton; Southern Seaboard includes AL, GA, NC, SC, and VA 

cotton; Fruitful Rim includes AZ, CA, FL, Southern TX, Mississippi Portal includes AR, LA, MS, and TN cotton.

2 Commercial fertilizer, soil conditioners, and manure.

3 Custom operations, fuel, lube, electricity, repairs, purchased irrigation water, and interest on operating costs.

4 Hired labor, opportunity cost of unpaid labor, capital recovery of machinery and equipment, opportunity cost of land, taxes and 

insurance and general farm overhead.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 124 of 946

Cotton (Gossypium spp.) is grown in the U.S. across southern states where the climate is warmer and 

the season is longer (see Figures II.B-2 and II.B-3). The total U.S. cotton acreage in the past 10 

years has varied from approximately 9.15 to 15.77 million planted acres, with the lowest acreage 

recorded in 2009 and the highest in 2001 (Table II.G-8).

Average cotton yields have varied from 632 to 879 pounds per acre over this same time period. 

Total annual cotton production ranged from 12.19 to 23.89 million bales (480 pounds/bale) over the 

past ten years. The variations observed in cotton acreage and production is driven by current 

market conditions, rather than agronomic considerations. According to data from USDA-NASS 

(USDA-NASS, 2011b), cotton was planted on approximately 11 million acres in the U.S. in 2010, 

producing approximately 18 million bales of cotton (Table II.G-8). The value of cotton production 

reached $7.32 billion in the U.S. in 2010 (USDA-NASS, 2011b).

U.S. cotton production is divided into the following four major cotton growing regions, which span 

the southern and southwestern states: Southeast region (AL, FL, GA, NC, SC, and VA), Midsouth 

region (AR, LA, MS, MO, and TN), Southwest region (KS, NM, OK, and TX), and West region 

(AZ and CA) (Table II.G-9). Cotton planting and production figures for these regions in 2010 are 

shown in Table II.G-9 and discussed below (USDANASS, 2011e). Approximately 5.6 million acres 

of cotton were planted in Texas, representing about 51% of the total U.S. cotton acres. Texas 

produced 8.1 million bales (480 pounds/bale) of cotton, which represents approximately 44% of the 

U.S. cotton production. The second largest production state for cotton was Georgia with 

approximately 12% of U.S. cotton production. Average cotton yields across the four cotton 

growing regions ranged from 727 to 1416 pounds cotton lint per acre, with the highest yields in the 

West with full irrigation, and the lowest yields in areas such as Alabama, Oklahoma, and Texas, 

where little to no irrigation is employed (Table II.G-9). The average cotton yield across all regions is 

821 pounds cotton lint per acre. The value of the cotton lint production among the four regions 

ranged from $0.86 billion in the West region to $3.35 billion in the Southwest region. The total 

value of the cottonseed production in the U.S. in 2010 was $1 billion with the value among the 

regions ranging from $134 million in the West region to $461 million in the Southwest region. 

II.G.1.c.(2) Organic Cotton Production

The USDA census of organic agriculture reported organic cotton farming on 30 farms in the U.S. in 

2008, two in Arizona, three in New Mexico, four in California, and 21 in Texas (USDA-NASS 

2008a). Texas (66%) and New Mexico (20%) together accounted for approximately 86% of the 

production. Based on USDA-ERS data, between 1997 and 2008, organic cotton acreage ranged 

from 9,213 acres in 2004 to 15,377 acres in 2008 (USDA-ERS 2008). In 2008 about 0.16% of the 

total 9.41 million acres of cotton was produced organically (USDA-ERS 2008). In recent years, 

small and sporadic acreages of organic cotton production have been cultivated in other states, 

including Missouri, Illinois, Kansas, Tennessee, and Colorado (USDA-ERS 2010c). Based upon 

recent trend information, the presence of GE cotton varieties on the market has not affected the 

ability of organic production systems to maintain their market share. Between 2000 and 2008, 

although 11 GE cotton events were deregulated and the percent of GE cotton in the market was 

near or above 90% and the acreage of organic cotton production remained at approximately 15,000 

acres (USDA-APHIS 2013c; USDA-ERS 2008).

The South Plains area of Texas is one of the primary regions for organic cotton production 

(TOCMC 2011b). Features that make the South Plains well-suited for organic cotton production 

include cold enough winter temperatures to limit insect pressure and to provide a hard freeze to 
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defoliate the cotton plants prior to harvesting, and a sunny climate and quick-drying soils to facilitate 

timely mechanical weed control. As many of these farmers do not irrigate, yields are heavily 

dependent upon rainfall (TOCMC 2011b).

Organic cotton growing practices include the use of natural defoliants; beneficial insects for pest 

control; compost, manure, and crop rotations for fertilizers; and hand-weeding, mechanical 

cultivation, cover crops and mulching for weed control. The same gins and spinning mills used for 

non-organic cotton are also used for organic cotton; however, they must be shut down and cleaned 

before processing the organic cotton, which adds to production costs (TOCMC 2011a).

Most U.S. organic cotton growers sell their cotton products through a marketing cooperative, the 

largest of which is the TOCMC, with approximately 30 members (OTA 2012; TOCMC 2011b). 

Cottonseed is marketed to organic dairies for feed (TOCMC 2011b). According to a survey 

conducted by OTA, organic cotton growers’ biggest barriers to planting more organic cotton are 

finding a market willing to pay the added costs of organic products, production challenges such as 

weed and insect control, and labor costs. “Growers also cited competition from international 

organic cotton producers, as well as the cost of transition to organic” (OTA 2010).
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Table II.G-8. Cotton Production in the U.S., 2000-20101

Year

Acres Planted 

(×1000)

Acres 

Harvested 

(×1000)

Average 

Yield 

(lbs/acre)

Total Production 

(480 lb bales)

Value 

(billions $)

2010 10,973 10,707 821 18,314,500 7.318

2009 9,150 7,691 777 12,187,500 3.788

2008 9,471 7,569 813 12,815,300 3.021

2007 10,872 10,489 879 19,206,900 5.653

2006 15,274 12,732 814 21,587,800 5.013

2005 14,245 13,803 831 23,890,200 5.695

2004 13,659 13,057 855 23,250,700 4.853

2003 13,480 12,003 730 18,255,200 5.517

2002 13,958 12,417 665 17,208,600 3.777

2001 15,769 13,828 705 20,302,800 3.122

2000 15,517 13,053 632 17,188,300 4.260

1

(USDA-NASS 2011d)
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Table II.G-9. U.S. Cotton Production by Region and State in 20101

Region/State

Acres 

Planted 

(thousands)

Acres 

Harvested 

(thousands)

Average Yield 

(pounds/acre)

Total 

Production 

(thousand 

bales)

Cotton Lint 

$ Value 

(thousands)

Cottonseed 

$ Value 

(thousands)

Southeast 

Region

Alabama 340 337 684 480 199,066 20,856

Florida 92 89 809 150 54,792 5,720

Georgia 1,330 1,320 811 2,230 926,966 91,120

North 

Carolina

550 545 854 970 338,957 44,992

South 

Carolina

202 201 872 365 136,656 16,756

Virginia 83 82 685 117 46,051 6,300

Region 

Totals

2,597 2,574 804 4312 1,702,488 185,744

Midsouth 

Region

Arkansas 545 540 1,049 1,180 395,914 71,400

Louisiana 255 250 864 450 174,960 24,024

Mississippi 420 415 983 850 308,856 44,616

Missouri 310 308 1,068 685 226,214 40,630

Tennessee 390 387 843 680 275,482 42,180

Region 

Totals

1,920 1,900 971 3,845 1,381,426 222,850

Southwest 

Region

Kansas 51 49 784 80 34,675 3,712

New Mexico 50 49 1,084 110 46,721 7,215

Oklahoma 285 270 738 415 180,276 20,727

Texas 5,567 5,367 723 8,082 3,083,472 429,814

Region 

Totals

5,953 5,734 727 8,687 3,345,144 461,468

West

Arizona 198 196 1,460 595 246384 46,200

California 306 303 1,388 876 610042 87,599

Region 

Totals

504 499 1,416 1,471 856,426 133,799

U.S. Total 10,973 10,707 821 18,315 7,317,704 1,003,861

1

(USDA-NASS 2011e)
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II.G.2. Trade Economic Environments of Soybean and Cotton

II.G.2.a. Trade Economic Environment: Soybean

The United States produces approximately one-third of the global soybean supply (ASA 2012). In 

2011, the U.S. exported 1.3 billion bushels of soybean, which accounted for 37 percent of the 

world’s soybean exports. In total, the U.S. exported $30.7 billion worth of soybean and soybean 

products globally in 2012 (ASA 2011; USDA-FAS 2013a). China is the largest export market for 

U.S. soybean with purchases totaling $15 billion. Mexico is the second largest export market with 

sales of $1.9 billion in the same year (Table II.G-10). Other important markets include Japan and 

the EU. 

The U.S., along with Brazil, Argentina, Paraguay, and Canada, account for 97% of the bulk soybean 

exported, while Argentina, Brazil, the U.S., India, and Paraguay account for 94.1% of the soybean 

meal exported (Table II.G-11). Argentina, the U.S., and Brazil are the dominant countries in terms 

of soybean oil exports accounting for 80.2% (Table II.G-11). Table II.G-12 presents the top ten

U.S. export markets for soybean by volume for 2010 and 2011, during which China, Mexico, and the 

European Union’s 27 member countries (EU-27) were the top 3 importers (USDA-ERS 2011d). As 

of March 2011, U.S. exports of soybean valued $13.79 billion, soybean meal approximately $2.1 

billion, and soybean oil approximately $1.2 billion (USDA-ERS-FAS 2011). China, the EU-27, 

Mexico, and Japan are the major importers of world bulk soybean, accounting for 80.1% of total 

imports, whereas the EU-27, Vietnam, Thailand, Indonesia, and Japan are the largest importers of 

soybean meal with a world share of 57.6% (USDA-FAS, 2011a). For soybean oil, China and India 

are the major importers with a world share of 35.8% (USDA-FAS 2011a). U.S. soybean exports are 

projected to increase to approximately 1.5 billion bushels (33.2 million metric tons) in 2020 (USDA 

2011).

Approximately 94% of the world’s soybean seed supply was crushed to produce soybean meal and 

oil in 2008 (Soyatech 2010), and the majority was used to supply the feed industry for livestock use 

or the food industry for edible vegetable oil and soybean protein isolates.

Soybean exports in the form of bulk beans, meal, and oil are a major share of the total agricultural 

exports for the U.S., representing 20.1% of the total value of U.S. exports. The value of U.S. 

agricultural exports was $108.67 billion in 2010 (USDA-ERS 2011c). Bulk soybeans accounted for 

$16.9 billion of this total, ranking first among all agricultural commodities, while soybean meal, at a 

value of $3.78 billion, and soybean oil, at a value of $1.35 billion, ranked 6th and 16th, respectively 

(USDA-ERS 2011c). The U.S. was responsible for 44.0% of the world’s bulk soybean exports, 

18.2% of the world’s soybean meal exports, and 16.8% of the world’s soybean oil exports (Tables 

II.G-13, II.G-14). 

Soybean meal represented 68% of the protein meal produced worldwide, though soybean ranked 

behind palm in terms of worldwide vegetable oil production (USDA-FAS 2011c). Similarly, soybean 

held the largest share of protein meal consumed worldwide, mainly as animal feed (USDA-FAS 

2011c), with soybean oil again coming in second behind palm oil in terms of worldwide vegetable oil 

consumption (USDA-FAS 2011c).
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Table II.G-10. U.S. Export Markets for Soybean and Soybean Products.

Top Ten U.S. Export Customers 2012 (millions of dollars)*

Soybean Exports Soybean Meal Exports Soybean Oil Exports

China 14,973 Mexico 654 China 265

Mexico 1,862 Philippines 599 Mexico 209

Japan 1,127 Canada 485 Morocco 162

Indonesia 994 Venezuela 348 India 96

Germany 867 Ecuador 258 Nicaragua 60

Taiwan 768 Morocco 218 Venezuela 54

Egypt 739 Egypt 212 Canada 39

Turkey 457 Dominican Republic 194 Colombia 34

Thailand 407 Guatemala 150 Jamaica 32

South Korea 395 Japan 149 Domican Republic 27

Other 2,116 Other 1,589 Other 181

Total 24,705 Total 4,856 Total 1,159

*Values of exports are listed in millions of dollars

Source: (USDA-FAS 2013b)
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Table II.G-11. World Soybean Exports in 2009/2010.

Location Soybean Bulk Soybean Meal Soybean Oil

(million metric tons)

Argentina 13.09 24.91 4.45

Bolivia --

1

-- 0.26

Brazil 28.58 12.99 1.45

Canada 2.25 -- --

EU-272-- -- 0.38

India -- 3.15 --

Paraguay 5.35 1.12 0.24

Russia -- -- 0.17

United States 40.85 10.14 1.52

Other 2.53 3.29 0.79

Source: USDA-FAS (2011c).

1

-- = No Data

2 European Union 27 member countries

Table II.G-12. Top 10 U.S. Soybean Export Markets in 2010/2011.

Location

January-October

2010

January-October

2011 October 2010 October 2011

(million metric tons)

China 15.65 13.86 5.58 3.88

Mexico 3.02 2.76 0.56 0.51

EU-2711.30 1.41 0.99 0.12

Japan 2.03 1.39 0.24 0.11

Taiwan 2.03 1.32 0.44 0.067

Indonesia 1.18 1.11 0.16 0.081

Egypt 0.86 0.57 0.12 0.14

Turkey 0.58 0.42 0.17 0.0029

South Korea 0.26 0.31 0.036 0.012

Syria 0.14 0.23 0.039 0.018

World Total 29.92 25.26 8.00 5.26

Source: (USDA-ERS 2011d)

1 European Union 27 member countries
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Table II.G-13. U.S. and Rest of World (ROW) Soybean Supply and Disappearance12009/10.

Soybeans Soybean Meal Soybean Oil

U.S. ROW U.S. ROW U.S. ROW

(Million Metric Tons)

Total 95.58 294.71 38.19 184.03 10.24 40.13

------------------------------------Supply------------------------------------

Beginning Stocks 3.76 38.82 0.21 4.20 1.30 1.62

Production 91.42 168.85 37.83 127.45 8.90 29.87

Imports 0.40 87.04 0.15 52.38 0.05 8.64

-------------------------------Disappearance-------------------------------

Crush 47.67 161.84 --

2

-- -- --

Feed, Seed & 

Residual 2.95 26.09 -- -- -- --

Domestic -- -- 27.78 132.84 7.20 31.06

Exports 40.85 51.89 10.14 45.56 1.52 7.54

Ending Stocks 4.11 54.89 0.27 5.63 1.52 1.53

Source: USDA-ERS (USDA-ERS 2011e).

1 Disappearance is the consumed supply 2No data

Table II.G-14. World Soybean Production in 2009/2010.

Location Soybean Soybean Meal Soybean Oil

(million metric tons)

Argentina 55 26.62 6.48

Brazil 69 26.12 6.47

Canada 4 --

1

--

China 15 38.64 8.73

EU-272-- 9.88 2.28

India 10 5.99 1.34

Mexico -- 2.83 0.64

Paraguay 7 -- --

United States 91 37.83 8.90

Other 11 17.37 4.06

Source: USDA-FAS (2011c).

1

-- = No Data

2 European Union 27 member countries
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II.G.2.b. Trade Economic Environment: Cotton

Cotton is a crop that is primarily grown for fiber used in textiles. After ginning of the primary 

commodity, fiber, the cottonseed and cottonseed by-products (meal, hulls, linters, and oil) are 

utilized for various feed and industrial components.

Cottonseed currently comprises 10% of the world’s oilseed production (USDA-FAS 2010), 

exceeded only by soybean (58%) and rapeseed (13%). Cottonseed is processed into four major byproducts: oil, meal, hulls, and linters. Cottonseed oil is used as a primary source of vegetable oil, in 

the United States, and is utilized in many food applications. Cottonseed meal, hulls and whole 

cottonseed are natural sources of protein, fiber, and energy. Cottonseed meal can be used in both 

ruminant and monogastric rations while hulls serves as a source of roughage for ruminant feeds and 

fiber for monogastric rations. In addition, cottonseed is concentrated as feed, providing protein and 

energy for ruminant rations. Consequently, cottonseed and cottonseed by-products are primarily 

used domestically with approximate volumes of 1.3% of whole cottonseed, 10.8% of meal, 28.7% 

oil from US production being exported (Monsanto 2013).

Trade of cotton lint or fiber is particularly important for cotton. About 38% of the world’s 

consumption of cotton fiber, a larger share than for wheat, corn, soybeans, or rice, crosses 

international borders before processing (Meyer, et al. 2007). Through trade in yarn, fabric, and 

clothing, much of the world’s cotton again crosses international borders at least once more before 

reaching the final consumer (Meyer et al. 2007).

Starting in the 1930s, the U.S., Canada, and Europe entered into trade agreements that set limits on 

the amount of foreign-made apparel and textiles that could be imported into the U.S. The last of 

these agreements, the Multifibre Arrangement (MFA), ended in 2005 (Meyer et al. 2007). 

Consumption of cotton by U.S. textile mills peaked in 1997. Since then, U.S. mill use of cotton has 

dropped by approximately 50% in 2005 and by nearly 70% in 2009 (USDA-ERS 2009). This change 

in foreign-made textile imports resulted in increased global competition for import and export of 

raw cotton, as well as finished textiles (Meyer et al. 2007). U.S. consumer demand for cotton 

products remains strong, but imported clothing now accounts for most purchases by U.S. 

consumers (USDA-ERS 2009). The USDA-ERS reports that U.S. cotton mills consumed 60% of 

the domestic cotton through the 1990s, but not long after the end of MFA quotas, 70% of the U.S. 

cotton lint was exported (Meyer et al. 2007).

The cotton industry continues to face many of the supply and demand concerns confronting other 

field crops. However, because cotton is used primarily in manufactured products, such as clothing 

and home furnishings, the industry faces additional challenges associated with the economic wellbeing of downstream manufacturing industries, as well as the general economic well-being of the 

final consumer (USDA-ERS 2009).

II.G.3. Public Perceptions of Genetically Engineered Crops in Food

Growing urbanization over the last century and a half has left the American population 

geographically and generationally removed from the farm. Fewer than 2% of the American 

population live and work on farms. Surveys indicate that consumers understand very little about the 

food they consume (Godwin, et al. 2005; Lusk 2011). 
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The food production system is complex, comprised of a number of actors and institutions along an 

extensive value chain. The system increasingly relies on scientifically and technically complex 

production methods and inputs to achieve production efficiencies to meet demand (Lang 2013). 

These rapid technological changes create uncertainties for the public (Arnot 2011; 2013; Ryan and 

Doerksen 2013). Rapid growth in internet usage and rapid adoption of mobile devices and use of 

social media offers the consumer immediate access to an information-rich environment. The role of 

mass media and the rise of citizen journalist as well as the influence of celebrity have created an 

environment where distorted or misleading information about food and the food production system 

rapidly circulates. This has led to staunch and vocal opposition to products of genetic engineering 

(Chassy 2007) which in turn has had an impact on the general public’s perception of genetically 

engineered (also referred to as GM) crops. This shift in consumer perceptions also plays out in other 

ways economically and politically. In recent years, there have been a number of state ballot initiatives 

in the US that would require mandatory labeling of genetically engineered-derived products. For 

example, California’s Proposition 37, which would have required labeling of GM foods, was 

presented and defeated on the November 2012 ballot. Proposition 37 has spurred another two 

dozen state and municipal level initiatives (Clark, et al. 2013). The FDA provides guidelines on 

voluntary labeling of foods derived from genetically engineered crops (U.S. FDA 2001a; 2013).

Studies on consumer preferences of food derived from genetically engineered crops (“GM food”) 

have been conducted in over 20 countries based on a number of factors including willingness to pay 

(Colson, et al. 2011). Yet, consumer preferences of GM food play out in different ways under 

different survey conditions which speak to “wildly differing results” of studies (Colson et al. 2011). 

Results are significantly influenced by the methods used to elicit those preferences, e.g., mail, phone 

surveys, experimental auctions, in-person surveys (Lusk 2011). Given the differing results, it is 

difficult to draw any definitive conclusions on consumer perceptions about GM foods (Lusk 2011). 

It has been reported, however, that US consumers are more accepting of GM foods that their 

European counterparts (Lusk 2011). This has been confirmed through economic experiments 

involving real food and real money by Lusk et al (2006). 

Although scientific literacy, overall, has been rising in the United States, the level of public 

confusion is greatest in the area of the life sciences. Public understanding of biotechnology and 

food, in general, is very low (The Mellman Group 2006). Lusk (2011) reports on a survey by the Pew 

Initiative on Food and Biotechnology (The Mellman Group 2006). Only 26% of consumers 

surveyed believe that they had consumed a GM food and 74% indicated that they had little to no 

knowledge about the government regulation of food. Lusk et al (2006) conducted a meta-analysis 

where 82% of the 57 studies demonstrated a willingness to pay a premium to avoid non-GM foods. 

Other results of the meta-analysis suggest that consumers are most averse to the use of genetic 

engineering in meat product and least averse to its use in oil (Lusk 2011). Despite ‘stated’ low to no 

preference for GM foods, the market for “GM-free” food remains quite small in the United States 

(Lusk 2011). 

While some studies reveal that information can shift consumer preferences (Colson et al. 2011; 

Huffman, et al. 2003). Others suggest that top-down, fact-focused approaches are a flawed 

approach to influencing consumer perceptions (Ryan 2013; Sapp, et al. 2009). Public opinion or 
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consumer preferences are clearly not formed on scientific evidence alone. In a world of 

uncertainties, choices in the marketplace are influenced not only by preferences but also by beliefs 

(Lusk 2011).

44

III. ALTERNATIVES

III.A. INTRODUCTION & DESCRIPTION OF ALTERNATIVES

The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service 

(APHIS) is responsible for regulating the introduction (importation, interstate movement, and 

environmental release) of genetically engineered (GE) organisms that are known to, or could, pose a 

plant pest risk. GE organisms are considered to be regulated articles if the donor organism, 

recipient organism, vector, or vector agent used in their creation is a member of a taxonomic group 

listed in the regulations in 7 CFR Part 340 and is known to be a plant pest, or the plant pest status of 

that organism is not known. A person may petition APHIS to evaluate submitted data and assess 

whether a particular regulated article is unlikely to pose a plant pest risk and, therefore, should no 

longer be subject to the regulations in 7 CFR Part 340. Pursuant to 7 CFR § 340.6, the petitioner is 

required to provide information related to plant pest risk that the agency uses to assess whether the 

regulated article is unlikely to present a greater plant pest risk than the unmodified organism. If, 

based on this information, the agency concludes that the article is unlikely to pose a greater plant 

pest risk, the agency may make a determination to approve the petition and confer nonregulated 

status on the regulated article. Thereafter, APHIS would no longer require permits or notifications 

for the introduction of the GE organism. 

This assessment considers whether to approve two petitions seeking a determination of 

nonregulated status for soybean and cotton cultivars genetically engineered to be resistant to 

herbicides. The first petition, APHIS Petition Number 10-188-01p, seeks a determination of 

nonregulated status of soybean (Glycine max) designated as event Dicamba Tolerant Soybean MON 

87708 (hereinafter referred to as DT soybean), which has been genetically engineered for tolerance 

to the herbicide dicamba. The second petition, APHIS Petition Number 12-185-01p, seeks a 

determination of nonregulated status of cotton (Gossypium spp.) designated as event Dicamba 

Glufosinate Tolerant Cotton MON 87701 (hereinafter referred to as DGT cotton), which has been 

genetically engineered for tolerance to the herbicides dicamba and glufosinate. 

This assessment concludes that both DT soybean and DGT cotton are no more likely to pose a 

plant pest risk than other soybean or cotton varieties. This assessment also addresses the potential 

impacts on the human environment of DT soybean and DGT cotton use in American agriculture—

including the potential selection of dicamba resistant weeds as a potential effect of altered herbicide 

use— if DT soybean and DGT cotton are granted nonregulated status. These effects are considered 

in four reasonable alternatives discussed in greater detail below. The alternatives represent a full 

range of reasonable alternatives in reference to the petitions for nonregulated status, and are framed 

to highlight the issues associated with the cultivation of DT soybean and DGT cotton if each 

 

44 Lusk (2011) suggests that consumer beliefs have not been studied in a theoretically consistent manner by economists. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 135 of 946

determined to have met the criteria to be deregulated. These alternatives vary in their feasibility 

based on regulatory and economic considerations. The four reasonable and appropriate alternatives 

include: 

 Deny both petitions for determination of nonregulated status (No Action 

Alternative);

 Approve the petition for determination of nonregulated status of DT soybean, and 

deny the petition for determination of nonregulated status of DGT cotton; and

 Approve the petition for determination of nonregulated status of DGT cotton, and 

deny the petition for determination of nonregulated status of DT soybean;

 Grant both petitions for determination of nonregulated status (full deregulation of 

DT soybean and DGT cotton) (preferred alternative).

Additional alternatives (described in Section III.F) were considered but eliminated from further 

consideration because they were either unreasonable or inappropriate since they failed to meet the 

regulatory program’s legally authorized purpose and need.

III.B. ALTERNATIVE 1 – DENY BOTH PETITIONS FOR DETERMINATION OF

NONREGULATED STATUS (NO ACTION ALTERNATIVE)

Under Alternative 1, the petitions seeking a determination of nonregulated status of DT soybean 

and DGT cotton would be denied. DT soybean and DGT cotton would accordingly remain 

regulated articles under 7 CFR Part 340, and all environmental releases and interstate movements of 

DT soybean and DGT cotton would continue to be subject to APHIS’ biotechnology regulations 

and the requirements of 7 CFR Part 340. Because DT soybean and DGT cotton and progeny 

derived from DT soybean and DGT cotton would remain regulated articles under 7 CFR Part 340, 

Alternative 1 would maintain the status quo. Alternative 1 therefore constitutes the No Action 

Alternative. Notifications or permits with conditions specified by APHIS would be required to 

move viable plant material and to plant DT soybean or DGT cotton outdoors, and measures to 

ensure physical and reproductive confinement would continue to be implemented. Deregulation of 

DT soybean and DGT cotton would not be permitted under Alternative 1.

This alternative is not the preferred alternative because, as demonstrated in the petitions for 

deregulation and Appendix G of this Environmental Report DT soybean and DGT cotton are 

unlikely to present a greater plant pest risk than the conventional counterparts. Choosing this 

alternative therefore would not satisfy the purpose and need of making a determination of plant pest 

risk status and responding to the petition for nonregulated status. Under the no-action alternative, 

growers will likely continue to use biotechnology-derived herbicide-tolerant soybean and cotton 

products that have been deregulated by APHIS, as well as herbicides to control weeds in soybean 

and cotton fields. Biotechnology-derived herbicide-tolerant varieties currently account for 

approximately 94% of soybean production and 73% percent of cotton production in the United 

States. Deregulated varieties would continue to be available commercially, and would be expected to 

continue to be widely grown, under this alternative. Because of existing resistance to currently 

available herbicides used in soybean and cotton production, and in the absence of new herbicide 

options, the number of weed populations and species with multiple resistances in soybean and 
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cotton production areas may increase. So too may resistance to herbicide classes that are being 

relied on to manage current levels of resistance to glyphosate and other herbicides. 

III.C. ALTERNATIVE 2 - APPROVE THE PETITION FOR DETERMINATION OF

NONREGULATED STATUS OF DT SOYBEAN, AND DENY THE 

PETITION FOR DETERMINATION OF NONREGULATED STATUS 

OF DGT COTTON

Under Alternative 2, the petition seeking a determination of nonregulated status of DT soybean 

would be granted, and DT soybean and its progeny would no longer be regulated articles under 7 

CFR Part 340. Permits issued or notifications acknowledged by APHIS would no longer be 

required for introductions of DT soybean, and growers could freely move and plant DT soybean 

without further oversight from the agency. The petition seeking a determination of nonregulated 

status of DGT cotton, however, would be denied, and DGT cotton and its progeny would remain 

regulated articles under 7 CFR Part 340. All environmental releases and interstate movements of 

DGT cotton would continue to be subject to APHIS’ biotechnology regulations and the 

requirements of 7 CFR Part 340. Notifications or permits with conditions specified by APHIS 

would be required to move viable plant material and to plant DGT cotton outdoors, and measures 

to ensure physical and reproductive confinement would continue to be implemented.

As demonstrated in the petitions for deregulation and Appendix G of this Environmental Report, 

DT soybean is unlikely to pose a greater plant pest risk than its conventional counterpart. 

Accordingly, it would be appropriate to conclude that a determination of nonregulated status of DT 

soybean is consistent with the plant pest provisions of the PPA, the regulations codified at 7 CFR 

Part 340, and the biotechnology regulatory policies in the Coordinated Framework. Approving the 

petition for DT soybean is also consistent with recent Ninth Circuit precedent, which provides that 

once a GE organism is determined not to pose a plant pest risk, it can no longer be subject to the 

plant pest provisions of the PPA or regulation under 7 CFR Part 340.45 

However, this alternative is not the preferred alternative because, as demonstrated in the petitions 

for deregulation and Appendix G of this Environmental Report, DGT cotton is unlikely to pose a 

greater plant pest risk than its conventional counterpart. It would therefore be appropriate to 

conclude that choosing this alternative would not satisfy the purpose and need of making a 

determination of plant pest risk status and responding to the petition for nonregulated status. The 

plant pest provisions of the PPA and the regulations at 7 CFR Part 340 do not justify denying a 

petition for determination of nonregulated status of DGT cotton where DGT cotton has not been 

found to pose a greater plant pest risk than its conventional counterpart. Moreover, under this 

alternative, growers will continue to use biotechnology-derived herbicide-tolerant cotton products 

that have been deregulated by APHIS, as well as herbicides to control weeds in cotton fields. 

Biotechnology-derived herbicide-tolerant varieties currently account for approximately 73% of 

cotton production in the United States. Deregulated varieties would continue to be available 

commercially, and would be expected to continue to be widely grown, under this alternative. 

Because of existing resistance to currently available herbicides used in cotton production, and in the 

 

45 Id.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 137 of 946

absence of new herbicide options, the number of weed populations and species with multiple 

resistance in cotton production areas may increase. So too may resistance to herbicide classes that 

are being relied on to manage current levels of resistance to glyphosate and other herbicides.

III.D. ALTERNATIVE 3 - APPROVE THE PETITION FOR DETERMINATION OF

NONREGULATED STATUS OF DGT COTTON, AND DENY THE 

PETITION FOR DETERMINATION OF NONREGULATED STATUS 

OF DT SOYBEAN

Under Alternative 3, the petition seeking a determination of nonregulated status of DGT cotton 

would be granted, and DGT cotton and its progeny would no longer be regulated articles under 7 

CFR Part 340. Permits issued or notifications acknowledged by APHIS would no longer be 

required for introductions of DGT cotton, and growers could freely move and plant DGT cotton 

without further oversight from the agency. The petition seeking a determination of nonregulated 

status of DT soybean, however, would be denied, and DT soybean and its progeny would remain 

regulated articles under 7 CFR Part 340. All environmental releases and interstate movements of 

DT soybean would continue to be subject to APHIS’ biotechnology regulations and the 

requirements of 7 CFR Part 340. Notifications or permits with conditions specified by APHIS 

would be required to move viable plant material and to plant DT soybean outdoors, and measures to 

ensure physical and reproductive confinement would continue to be implemented.

DGT cotton is unlikely to pose a greater plant pest risk than conventional cotton, as demonstrated 

in the petitions for deregulation and Appendix G of this Environmental Report. Accordingly, it 

would be appropriate to determine that nonregulated status of DGT cotton is consistent with the 

plant pest provisions of the PPA, the regulations codified at 7 CFR Part 340, and the biotechnology 

regulatory policies in the Coordinated Framework. A determination of nonregulated status is also 

consistent with recent Ninth Circuit precedent, which provides that once a GE organism is 

determined not to pose a plant pest risk, it can no longer be subject to the plant pest provisions of 

the PPA or regulation under 7 CFR Part 340.46 

However, this alternative is not the preferred alternative because as demonstrated in the petitions for 

deregulation DT soybean is unlikely to present a greater plant pest risk than the unmodified parental 

organism. Choosing this alternative would not satisfy the purpose and need of making a 

determination of plant pest risk status and responding to the petition for nonregulated status. The 

plant pest provisions of the PPA and the regulations at 7 CFR Part 340 do not justify denying a 

petition for determination of nonregulated status of DT soybean where DT soybean has not been 

found to pose a greater plant pest risk than conventional soybean. Moreover, under this alternative, 

growers will continue to use biotechnology-derived herbicide-tolerant soybean products that have 

been deregulated by APHIS, as well as herbicides to control weeds in soybean fields. 

Biotechnology-derived herbicide-tolerant varieties currently account for approximately 94% of 

soybean production in the United States. Deregulated varieties would continue to be available 

commercially, and would be expected to continue to be widely grown, under this alternative. 

Because of existing resistance to currently available herbicides used in soybean productions, and in 

 

46 Id.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 138 of 946

the absence of new herbicide options, the number of weed populations and species with multiple 

resistance in soybean production areas may increase. So too may resistance to herbicide classes that 

are being relied on to manage current levels of resistance to glyphosate and other herbicides.

III.E. ALTERNATIVE 4 – GRANT BOTH PETITIONS FOR DETERMINATION OF

NONREGULATED STATUS (FULL DEREGULATION OF DT 

SOYBEAN AND DGT COTTON)

Under Alternative 4, the petitions seeking a determination of nonregulated status of DT soybean 

and DGT cotton, and all progeny derived from each, would be granted, and DT soybean and DGT 

cotton would no longer be regulated articles under 7 CFR Part 340. Permits issued or notifications 

acknowledged by APHIS would no longer be required for introductions of DT soybean and DGT 

cotton. Growers could therefore freely move and plant DT soybean and DGT cotton without 

further oversight from APHIS. It would be appropriate to conclude that this alternative best meets 

the purpose and need to respond appropriately to a petition for nonregulated status based on the 

requirements of 7 CFR Part 340 and the agency’s authority under the plant pest provisions of the 

Plant Protection Act (PPA). Because, as demonstrated in the petitions for deregulation and 

Appendix G of this Environmental Report, DT soybean and DGT cotton are unlikely to pose a 

greater plant pest risk than their conventional counterparts, a determination of nonregulated status 

of DT soybean and DGT cotton is a response that is consistent with the plant pest provisions of the 

PPA, the regulations codified at 7 CFR Part 340, and the biotechnology regulatory policies in the 

Coordinated Framework. This alternative is also consistent with recent Ninth Circuit precedent, 

which provides that once a GE organism is determined not to pose a plant pest risk, it can no longer 

subject to the plant pest provisions of the PPA or regulation under 7 CFR Part 340.47

Under this alternative, growers may have future access to DT soybean and DGT cotton and 

progeny derived from these events if the developer decides to commercialize DT soybean and DGT 

cotton. With the approval by EPA for the use of dicamba on DT soybean and DGT cotton48, and 

the integration of DT soybean and DGT cotton into the glyphosate-tolerant soybean and cotton 

systems through traditional breeding, the combined crop-tolerances to glyphosate, dicamba, and, for 

DGT cotton, glufosinate, would allow growers to utilize glyphosate, dicamba, and glufosinate 

herbicides in their weed management systems, as well as other herbicides currently registered for use 

in soybean and cotton. 

 

47 See Ctr. for Food Safety v. Vilsack, 718 F.3d 829 (9th Cir. 2013).

48 EPA has previously approved the use of glufosinate over the top of glufosinate tolerant cotton.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 139 of 946

III.F. ALTERNATIVES CONSIDERED BUT ELIMINATED FROM DETAILED 

EVALUATION

III.F.1. Approve Both Petitions For Determination of Nonregulated Status Only in Part 

(Isolation Distances, Geographic Restrictions, and Other 

Restrictions On Use)

In response to public concerns of gene flow between GE and non-GE plants, this analysis 

considered requiring an isolation distance separating DT soybean and DGT cotton from non-GE 

soybean and non-GE cotton production, respectively. Given that the petitions for deregulation DT 

soybean and DGT cotton demonstrate that they are unlikely to present a greater plant pest risk than 

their conventional counterparts, an alternative based on requiring isolation distances would be 

inconsistent with the statutory authority under the plant pest provisions of the PPA and regulations 

in 7 CFR Part 340.

This analysis also considered geographically restricting the production of DT soybean and/ or DGT 

cotton based on the location of production of non-DT soybean and non-DGT cotton in organic 

production systems or production systems for GE-sensitive markets. However, there are no 

geographic differences associated with any identifiable plant pest risks for DT soybean and DGT 

cotton. This alternative was rejected and not analyzed in detail because this analysis has concluded 

that DT soybean and DGT cotton do not pose a greater plant pest risk than their conventional 

counterparts, and will not exhibit a greater plant pest risk in any geographically restricted area. 

Therefore, such an alternative would not be consistent with the statutory authority conferred by the 

plant pest provisions of the PPA and regulations in 7 CFR Part 340, as well as the biotechnology 

regulatory policies embodied in the Coordinated Framework.

The imposition of isolation distances or geographic restrictions would not meet the purpose and 

need to respond appropriately to a petition for nonregulated status based on the requirements of 7 

CFR Part 340 and the plant pest provisions of the PPA. Nor would deregulating (approval whole)

DT soybean and DGT cotton only in part, under certain circumstances, absent a finding that DT 

soybean and DGT cotton pose a greater plant pest risk than their conventional counterparts. 

Consideration of a partial approval alternative is dependent upon a finding that the products in 

question have the potential to pose a plant pest risk in certain geographies or under certain 

conditions. It may then be appropriate to impose conditions upon the cultivation or use of the 

products in specific geographies or under conditions that mitigate the potential plant pest risk. 

However, DT soybean and DGT cotton have been thoroughly characterized, and extensive 

information has been presented demonstrating that DT soybean and DGT cotton do not present a 

plant pest risk under any circumstance. (See DT Soybean Petition for Deregulation #10-188-01p; 

DGT Cotton Petition for Deregulation #12-185-01p_1a; and Appendix G of this Environmental 

Report Therefore, from a plant pest risk perspective, there is no basis for imposing geographic or 

other restrictions on DT soybean and DGT cotton.

Moreover, the use of dicamba for agricultural purposes was first established in 1967, and, with the 

reregistration in 2006, the U.S. Environmental Protection Agency (EPA) recently reaffirmed that its 

use presents no unreasonable adverse effectswhen applied according to label directions, including in 

soybean and cotton production. The authority to determine whether and how dicamba may be used 

belongs solely to EPA; no other agency has the regulatory authority to restrict the use of pesticides 

or impose measures to mitigate their risk. Monsanto has applied for a label amendment for use of 

dicamba on DT soybean and DGT cotton. EPA will review the proposed label amendments and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 140 of 946

assess if the requested use pattern and use instructions meet the FIFRA standard of no unreasonable 

adverse effects. On the basis of this analysis demonstrating that there is no plant pest risk 

consideration or other risk that would lead to approval in part, and because only EPA has authority 

to regulate pesticides like dicamba and glufosinate, the alternative of approval in part was not 

considered further in this analysis. Any request to consider the effects of herbicide drift on 

downwind crops should properly be directed to EPA, which is the sole agency with authority to 

regulate pesticides.

III.F.2. Require Testing for DT Soybean and DGT Cotton

This analysis considered the appropriateness of requiring or providing testing for GE products in 

non-GE production systems. However, there are no nationally-established regulations involving 

testing, criteria, or limits of GE material in non-GE systems. Such a requirement would be 

extremely difficult to implement and maintain. Additionally, because DT soybean and DGT cotton 

do not pose a pose a greater plant pest risk than their conventional counterparts, the imposition of 

any type of testing requirement is inconsistent with the plant pest provisions of the PPA, the 

regulations at 7 CFR Part 340, and the biotechnology regulatory policies embodied in the 

Coordinated Framework. Moreover, this alternative is outside the scope of the decision being made 

by APHIS, which is whether or not to grant the petitions for nonregulated status of DT soybean 

and DGT cotton. An alternative with testing for GE products in non-GE production systems 

would be a regulatory program and not an alternative to full deregulation. Moreover, requiring 

testing of non-GE organisms would burden growers of conventional soybean and cotton crops who 

are not currently subject to the regulations of 7 CFR Part 340. Such a requirement would have no 

bearing on the introduction and dissemination of plant pests, and it is inconsistent with an equitable 

coexistence policy. Imposing such a requirement for DT soybean and DGT cotton, therefore, 

would not meet the purpose and need to respond appropriately to the petitions in accordance with 

regulatory authorities.

III.F.3. Ban All Planting of DT Soybean and DGT Cotton

Another alternative considered but rejected was to prohibit the growth of DT soybean and DGT 

cotton in the United States. This alternative would require current planting of DT soybean and 

DGT cotton to be removed from fields. Current seed stores would also need to be destroyed or 

shipped to countries that permit the use of these products. Non-DT soybean and non-DGT cotton 

varieties would not be available to growers who wish to grow soybean and cotton. Research and 

development of DT soybean and DGT cotton varieties would not be permitted.

This analysis rejected this alternative from further consideration because it does not meet the 

purpose and need to respond appropriately to the petitions in accordance with regulatory 

authorities. APHIS currently regulates DT soybean and DGT cotton under 7 CFR Part 340. Under 

this alternative, APHIS would not be able to authorize their introduction even with permits and 

notifications, which is currently done under the regulations. APHIS has issued many of these 

regulatory authorizations in the past and has not identified any plant pest-related justification to 

discontinue issuing permits or acknowledging notifications for DT soybean and DGT cotton. To 

prohibit all planting and growth of DT soybean and DGT cotton would be inconsistent with the 

government’s policies to allow the safe development of GE organisms. Further, this alternative 

would be inconsistent with the government’s policy and need to support the coexistence of GE and 

non-GE production systems.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 141 of 946

III.G. COMPARISON OF IMPACTS BY ALTERNATIVE MATRIX

Table III.G-1 below summarizes the environmental impacts of the proposed action and alternatives by resource area.

Table III.G-1 Summary of Impacts of Each Alternative

No Action Alternative 

For Both

Approval in Whole of 

DT Soybean But Not 

DGT Cotton

Approval in Whole of 

DGT Cotton But Not 

DT Soybean

Approval in Whole of 

Both

Agricultural Production

Crops Use & 

Biology

The use of herbicides in 

soybean and cotton 

production is expected to 

continue to increase as 

more growers in certain 

areas of the U.S. adopt 

diversified weed 

management strategies to 

combat hard-to-control 

herbicide-resistant weeds.

Some of the available 

herbicides may pose 

greater potential risks to 

animals or insects than 

dicamba. 

Conventional tillage 

practices may increase; 

increased use of tillage 

could have a small 

Effects to mammals that 

consume DT soybean 

seed would be no 

different than those 

possible from the 

consumption of 

commercially cultivated 

soybean. 

The impact to birds or 

other animals, including 

migratory birds and 

animals that may 

consume soybean forage 

or seed from DT 

soybean would be no 

different than possible 

impacts from 

commercially cultivated 

soybean. 

Effects to mammals that 

consume DGT cotton 

seed would be no 

different than those 

possible from the 

consumption of 

commercially cultivated 

cotton. 

The impact to birds or 

other animals, including 

migratory birds and 

animals that may 

consume seed from 

DGT cotton would be 

no different than 

possible impacts from 

commercially cultivated 

cotton. 

Use of herbicides is 

expected to increase as 

No effects to animals are 

anticipated from 

consumption of DT 

soybean or DGT cotton 

seed or forage.

Use of herbicides is 

expected to increase as 

more growers adopt 

diversified weed 

management strategies to 

combat hard-to-control 

and herbicide-resistant 

weeds, but dicamba is 

expected to displace 

some herbicides that 

would otherwise be used, 

and which could have a 

more significant 

environmental footprint.

The increased ability to 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 142 of 946

adverse impact on 

wildlife, as the crop 

residues that remain with 

the use of conservation 

tillage may provide shelter 

and food for wildlife, 

such as game birds and 

small animals.

Use of herbicides is 

expected to increase as 

more growers adopt 

diversified weed 

management strategies to 

combat hard-to-control 

and an increased number 

of herbicide-resistant 

weeds, but dicamba is 

expected to displace 

some herbicides that 

would otherwise be used, 

and which could have a 

more significant 

environmental footprint.

The increased ability to 

sustain use of 

conservation tillage is 

expected to result in a 

small positive impact on 

wildlife, as the crop 

residues that remain with 

the use of conservation 

tillage may provide 

shelter and food for 

wildlife, such as game 

birds and small animals.

more growers adopt 

diversified weed 

management strategies to 

combat hard-to-control 

and an increased number 

of herbicide-resistant 

weeds, but dicamba is 

expected to displace 

some herbicides that 

would otherwise be used, 

and which could have a 

more significant 

environmental footprint.

The increased ability to 

sustain use of 

conservation tillage is 

expected to result in a 

small positive impact on 

wildlife, as the crop 

residues that remain with 

the use of conservation 

tillage may provide 

shelter and food for 

wildlife, such as game 

birds and small animals.

sustain use of 

conservation tillage is 

expected to result in a 

small positive impact on 

wildlife, as the crop 

residues that remain with 

the use of conservation 

tillage may provide 

shelter and food for 

wildlife, such as game 

birds and small animals.

General 

Agronomic 

Practices 

Unchanged Unchanged Unchanged Unchanged

Tillage Increased tillage is likely 

to control problematic 

herbicide-resistant weeds

Conservation tillage 

levels should be 

preserved on soybean 

Conservation tillage 

levels should be 

preserved on cotton 

Conservation tillage 

levels should be 

preserved on soybean 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 143 of 946

acres because dicamba 

will provide an additional 

mode-of-action herbicide 

to combat resistant 

weeds

acres because dicamba 

will provide an additional 

mode-of-action herbicide 

to combat resistant 

weeds

and cotton acres because 

dicamba will provide an 

additional mode-ofaction herbicide to 

combat resistant weeds

Pest 

Management 

Unchanged Unchanged Unchanged Unchanged

Weed 

Management 

Growers would continue 

to use the glyphosatetolerant soybean system 

for broad spectrum weed 

control, other registered 

alternative herbicides 

alone or in combination 

with other herbicidetolerant soybean and/or 

cotton varieties for 

targeted hard-to-control 

weeds, and/or 

incorporate tillage into 

their practices.

The inability to integrate 

DT soybean or DGT 

cotton into the 

glyphosate-tolerant 

soybean and cotton 

systems could increase 

the potential for 

herbicide-resistant weed 

populations to evolve and 

spread in certain soybeanand cotton- producing 

Conservation tillage 

practices are expected to 

be sustained and 

potentially increase, and 

the DT soybean system 

will provide soybean 

growers with a more 

flexible and reliable weed 

management options and 

an additional mode-ofaction herbicide to 

combat resistant weeds. 

Hand weeding is 

expected to decrease as a 

result of the effective and 

reliable weed 

management option 

provided by DT soybean.

Cotton growers in 

certain areas of the U.S. 

would continue to 

experience weed control 

challenges with hard-tocontrol (e.g., 

morningglory) and 

Conservation tillage 

practices are expected to 

be sustained and 

potentially increase, and 

the DT soybean system 

will provide soybean 

growers with a more 

flexible and reliable weed 

management options and 

an additional mode-ofaction herbicide to 

combat resistant weeds. 

Hand weeding is 

expected to decrease as a 

result of the effective and 

reliable weed 

management option 

provided by DGT 

cotton.

Soybean growers in 

certain areas of the U.S. 

would continue to 

experience weed control 

challenges with hard-toSoybean and cotton 

growers would have the 

option of using dicamba 

for treatment of hard-tocontrol and glyphosateresistant weeds, 

providing an alternative 

mode-of-action with a 

more benign toxicity 

profile as compared to 

some alternative 

herbicides. 

Use of dicamba can 

mitigate the potential for 

development of 

resistance to other 

herbicides on soybean 

and cotton acres because 

of its broad activity on 

broadleaf weeds and low 

level of weed resistance.

Conservation tillage 

practices on soybean and 

cotton acreage are 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 144 of 946

areas of the U.S., resulting 

in the need for increased 

tillage, with 

corresponding adverse 

effects.

Growers in certain areas 

of the U.S. would 

continue to experience 

weed control challenges 

with hard-to-control (e.g., 

morningglory) and 

resistant weed species 

(eg., Palmer amaranth and 

waterhemp); the number 

of acres with resistant 

weeds is projected to 

increase due to lack of 

adequate weed control 

solutions.

The use of herbicides in 

soybean and cotton 

production is expected to 

continue to increase as 

more growers adopt 

diversified weed 

management strategies to 

combat hard-to-control 

and an increased number 

of herbicide-resistant 

weeds.

Some of the available 

herbicides may pose 

resistant weed species 

(eg., Palmer amaranth); 

the number of acres with 

resistant weeds is 

projected to increase due 

to lack of adequate weed 

control solutions.

Soybean growers would 

have the option of using 

dicamba for treatment of 

hard-to-control (e.g., 

morningglory) and 

resistant weed species 

(eg., waterhemp);, 

providing an alternative 

mode-of-action with a 

more benign toxicity 

profile as compared to 

some alternative 

herbicides. 

Use of dicamba can 

mitigate the potential for 

development of

resistance to other 

herbicides because of its 

broad activity on 

broadleaf weeds and low 

level of weed resistance, 

specifically on the 

summer spectrum of 

weeds known to infest 

soybean acres.

control and resistant 

weed species; the 

number of acres with 

resistant weeds is 

projected to increase due 

to lack of adequate weed 

control solutions.

Cotton growers would 

have the option of using 

dicamba for treatment of 

hard-to-control weeds, 

providing an alternative 

mode-of-action with a 

more benign toxicity 

profile as compared to 

some alternative 

herbicides.

Use of dicamba can 

mitigate the potential for 

development of 

resistance to other 

herbicides on cotton 

acres because of its 

broad activity on 

broadleaf weeds and low 

level of weed resistance.

Conservation tillage 

practices on cotton 

acreage are expected to 

be sustained and 

potentially increase, and 

expected to be sustained 

and potentially increase, 

and the DT soybean and 

DGT cotton systems will 

provide growers with 

more flexible and reliable 

weed management 

options. Hand weeding 

is expected to decrease as 

a result of the effective 

and reliable weed 

management option 

provided by DT soybean 

and DGT cotton.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 145 of 946

greater potential risks to 

animals or insects than 

dicamba. 

 

the DGT cotton system 

will provide cotton 

growers with more 

flexible and reliable weed 

management options. 

Weed Resistance Growers would continue 

to cultivate available 

herbicide-tolerant GE 

and non-GE soybean and 

cotton, using glyphosate 

alone or in combination 

with other nonglyphosate herbicides 

(including glufosinate) for 

weed management.

For soybean and cotton 

in certain areas of the 

U.S., there is a potential 

for glyphosate-resistant 

weed populations to 

evolve and develop, as 

well as the potential 

resistant populations to 

other alternative soybean 

herbicides to evolve and 

develop. 

The use of existing 

herbicides presents 

challenges to the grower’s 

ability to effectively 

achieve consistent control 

of problematic weeds in 

Growers would continue 

to cultivate available 

herbicide-tolerant GE 

and non-GE cotton, 

using glyphosate alone or 

in combination with 

other non-glyphosate 

herbicides (including 

glufosinate) for weed 

management.

The use of existing 

herbicides presents 

challenges to the 

grower’s ability to 

effectively achieve 

consistent control of 

problematic weeds in 

cotton such as Palmer 

amaranth. Thus, it is 

foreseeable that under 

the No Action 

Alternative, the inability 

to cultivate cotton 

varieties containing DGT 

cotton combined with 

the glyphosate tolerance 

trait could increase the 

potential for glyphosateGrowers would continue 

to cultivate available 

herbicide-tolerant GE 

and non-GE soybeans,

using glyphosate alone or 

in combination with 

other non-glyphosate 

herbicides for weed 

management, but 

additional weed 

resistance could develop 

in certain soybean 

acreage of the U.S. 

With respect to cotton, 

the ability to cultivate 

cotton varieties 

containing DGT cotton 

combined with the 

glyphosate tolerance trait 

could offer significant 

benefits in the effort to 

achieve consistent 

control of problematic 

weeds in cotton, such as 

Palmer amaranth. 

Even though dicamba 

has been used extensively 

on millions of acres for 

For soybean and cotton, 

the ability to cultivate 

varieties containing DT 

soybean and DGT 

cotton combined with 

the glyphosate tolerance 

trait could offer 

significant benefits in the 

effort to achieve 

consistent control of 

problematic weeds in 

cotton, such as Palmer 

amaranth and 

waterhemp. 

DT soybean and DGT 

cotton combined with 

glyphosate-tolerant 

soybean would provide 

the tools to directly 

mitigate the development 

of glyphosate- and other 

herbicide-resistant 

weeds.

Even though dicamba 

has been used extensively 

on millions of acres for 

over 40 years, to date 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 146 of 946

cotton such as Palmer 

amaranth. Thus, it is 

foreseeable that under the 

No Action Alternative, 

the inability to cultivate 

varieties containing DT 

soybean and DGT cotton 

combined with the 

glyphosate tolerance trait 

could increase the 

potential for glyphosateresistant weed 

populations to evolve and 

spread in certain cotton 

producing areas of the 

U.S. 

resistant weed 

populations to evolve 

and spread in certain 

cotton producing areas 

of the U.S. 

DT soybean combined 

with glyphosate-tolerant 

soybean would provide 

the tools to directly 

mitigate the development 

of glyphosate- and other 

herbicide-resistant 

weeds.

Even though dicamba 

has been used extensively 

on millions of acres for 

over 40 years, to date 

there are only four 

species in North America 

with known biotypes that 

are resistant to dicamba. 

Thus, DT soybean offer 

an excellent option to 

mitigate the development 

of herbicide-resistant 

weeds, or to manage 

weeds that are resistant 

to other herbicides.

over 40 years, to date 

there are only four 

species in North America 

with known biotypes that 

are resistant to dicamba. 

Thus, DGT cotton 

offers an excellent option 

to mitigate the 

development of 

herbicide-resistant 

weeds, or to manage 

weeds that are resistant 

to other herbicides.

there are only four 

species in North America 

with known biotypes that 

are resistant to dicamba. 

Thus, DT soybean and 

DGT cotton offer 

excellent options to 

mitigate the development 

of herbicide-resistant 

weeds, or to manage 

weeds that are resistant 

to other herbicides.

Organic 

Production

Unchanged Unchanged Unchanged Unchanged

Other Specialty 

Markets

Unchanged Unchanged Unchanged Unchanged
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 147 of 946

Seed Production Unchanged Unchanged Unchanged Unchanged

Physical Environment

Land Use 

Impacts

Unchanged Unchanged Unchanged Unchanged

Soil Quality 

Impacts

An increase in tillage, 

which is likely under the 

No Action Alternative, 

would negate many of the 

benefits of conservation 

tillage to soil, including 

improvement of soil 

structure, reduction of 

soil compaction, 

conservation of soil 

moisture, reduction of 

soil erosion and 

improvement of soil 

organic matter content. 

Conservation tillage acres 

are likely to remain the 

same, or potentially 

increase, on soybean 

acreage owing to the 

introduction of DT 

soybean combined with 

the glyphosate tolerance 

trait. Conservation 

tillage improves soil 

structure, reduces soil 

compaction, conserves 

soil moisture, reduces 

soil erosion and

improves soil organic 

matter content.

An increase in tillage is 

likely in cotton acreage, 

with corresponding 

adverse impacts on soil 

quality.

Conservation tillage acres 

are likely to remain the 

same, or potentially 

increase, on cotton 

acreage owing to the 

introduction of DGT 

cotton combined with 

the glyphosate tolerance 

trait. Conservation 

tillage improves soil 

structure, reduces soil 

compaction, conserves 

soil moisture, reduces 

soil erosion and 

improves soil organic 

matter content.

An increase in tillage is 

likely in soybean acreage, 

with corresponding 

adverse impacts on soil 

quality.

Conservation tillage acres 

are likely to remain the 

same, or potentially 

increase, on soybean and 

cotton acreage owing to 

the introduction of DT 

soybean and DGT 

cotton combined with 

the glyphosate tolerance 

trait.. Conservation 

tillage improves soil 

structure, reduces soil 

compaction, conserves 

soil moisture, reduces 

soil erosion and 

improves soil organic 

matter content.

Water Quality 

Impacts

An increase in tillage, 

which is likely under the 

No Action Alternative, 

would result in increased 

transport of sediments, 

nutrients and pesticides 

into surface water bodies, 

Conservation tillage acres 

are likely to remain the 

same, or potentially 

increase, on soybean 

acreage owing to the 

introduction of DT 

soybean combined with 

Conservation tillage acres 

are likely to remain the 

same, or potentially 

increase, on cotton 

acreage owing to the 

introduction of DGT 

cotton combined with 

Conservation tillage acres 

are likely to remain the 

same, or potentially 

increase, on soybean and 

cotton acreage owing to 

the introduction of DT 

soybean and DGT 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 148 of 946

resulting in overall 

adverse surface water 

impacts. 

the glyphosate tolerance 

trait., with corresponding 

benefits to surface water. 

An increase in tillage is 

likely in cotton acreage, 

with corresponding 

adverse impacts on water 

quality.

the glyphosate tolerance 

trait., with corresponding 

benefits to surface water. 

An increase in tillage is 

likely in soybean acreage, 

with corresponding 

adverse impacts on water 

quality.

cotton combined with 

the glyphosate tolerance 

trait., with corresponding 

benefits to surface water. 

Air Quality 

Impacts

The no action alternative 

may result in increased 

tillage, which could cause 

some adverse air quality 

impacts compared with 

full deregulation, but the 

differences may not be 

significant. 

Emissions from farm 

equipment, airborne soil 

erosion and pesticide

drift, as well as indirect air 

quality effects, e.g., 

nitrous oxide emissions 

associated with the use of 

nitrogen fertilizers, may 

also result under the no 

action alternative.

Not deregulating DGT 

cotton may result in 

increased tillage on 

cotton acreage, which 

could cause some 

adverse air quality 

impacts compared with 

full deregulation, but the 

differences may not be 

significant. 

Emissions may also be 

higher on cotton acreage 

from farm equipment, 

airborne soil erosion and 

pesticide drift, as well as 

indirect air quality 

effects, e.g., nitrous oxide 

emissions associated with 

the use of nitrogen 

fertilizers, under the no 

action alternative.

Air quality impacts are 

expected to be reduced 

Not deregulating DT 

soybean may result in 

increased tillage on 

soybean acreage, which 

could cause some 

adverse air quality 

impacts compared with 

full deregulation, but the 

differences may not be 

significant. 

Emissions may also be 

higher on soybean 

acreage from farm 

equipment, airborne soil 

erosion and pesticide

drift, as well as indirect 

air quality effects, e.g., 

nitrous oxide emissions 

associated with the use 

of nitrogen fertilizers, 

under the no action 

alternative.

Air quality impacts are 

Air quality impacts are 

expected to be reduced 

on soybean and cotton 

acres as a result of 

deregulation, but the 

differences may not be 

significant.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 149 of 946

on soybean acres as a 

result of deregulation, 

but the differences may 

not be significant.

expected to be reduced 

on cotton acres as a 

result of deregulation, 

but the differences may 

not be significant.

Climate Change 

Impacts

The no action alternative 

may result in increased 

tillage, which could cause 

some adverse climate 

impacts compared with 

full deregulation owing to 

reduced carbon emissions 

from lower farm 

equipment operations and 

increased carbon 

sequestration in the soil, 

but the differences are 

difficult to quantify.

Not deregulating DGT 

cotton may result in 

increased tillage, which 

could cause some 

adverse climate impacts 

compared with full 

deregulation owing to 

reduced carbon 

emissions from lower 

farm equipment 

operations and increased 

carbon sequestration in 

the soil, but the 

differences are difficult 

to quantify.

Climate change impacts 

on soybean acreage are 

expected to be improved 

after introduction of DT 

soybean combined with 

the glyphosate tolerance 

trait., but the differences 

are difficult to quantify.

Not deregulating DT 

soybean may result in 

increased tillage, which 

could cause some 

adverse climate impacts 

compared with full 

deregulation owing to 

reduced carbon 

emissions from lower 

farm equipment 

operations and increased 

carbon sequestration in 

the soil, but the 

differences are difficult 

to quantify.

Climate change impacts 

on cotton acreage are 

expected to be improved 

after introduction of 

DGT cotton combined 

with the glyphosate 

tolerance trait., but the 

differences are difficult 

to quantify.

Reduced tillage may 

provide climate change 

benefits, including 

reduced carbon 

emissions from lower 

farm equipment 

operations and increased 

carbon sequestration in 

the soil. Thus, climate 

change impacts on 

soybean and cotton 

acreage are expected to 

be improved after 

introduction of DT 

soybean and DGT 

cotton combined with 

the glyphosate tolerance 

trait., but the differences 

are difficult to quantify.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 150 of 946

Biological Impacts

Animal 

Communities

Increased use of tillage 

could have a small 

adverse impact on 

wildlife, as the crop 

residues that remain with 

the use of conservation 

tillage may provide shelter 

and food for wildlife, 

such as game birds and 

small animals. 

Reduced tillage on DT 

soybean acreage could 

have a small beneficial 

impact on wildlife. 

Potential impacts from 

dietary exposure to DT 

soybean are not expected 

to have any impact on 

animal communities. 

Reduced tillage on DGT 

cotton acreage could 

have a small beneficial 

impact on wildlife. 

Potential impacts from 

dietary exposure to DGT 

cotton are not expected 

to have any impact on 

animal communities. 

Reduced tillage on DT 

soybean and DGT 

cotton acreage could 

have a small beneficial 

impact on wildlife.

Potential impacts from 

dietary exposure to DT 

soybean or DGT cotton 

are not expected to have 

any impact on animal 

communities. 

Plant 

Communities

Unchanged Unchanged; there is no 

expectation that the 

introduction of DT 

soybean will alter the 

geographical range of 

commercial soybean 

cultivation and the 

potential environmental 

consequences of pollen 

transfer from DT 

soybean to other 

soybean or related Glycine

species is considered to 

be negligible because of 

the safety of the 

introduced proteins and 

lack of any selective 

advantage by the 

dicamba trait that might 

be conferred on the 

recipient feral soybean or 

Unchanged; there is no 

expectation that the 

introduction of DGT 

cotton will alter the 

geographical range of 

commercial cotton 

cultivation and the 

potential environmental 

consequences of pollen 

transfer from DGT 

cotton to other cotton or 

related Gossypium 

species is considered to 

be negligible because 

there are no native 

species of Gossypium 

found in cotton-growing 

areas, and because of the 

safety of the introduced 

proteins and lack of any 

selective advantage by 

Unchanged; introduction 

of DT soybean and 

DGT cotton are not 

expected to the 

geographical range of 

commercial soybean or 

cotton cultivation, or to 

pose significant risk of 

gene transfer. 

EPA regulates the use of 

herbicides and has 

concluded that dicamba 

and glufosinate offsite 

movement from labeled 

uses do not pose 

unreasonable adverse 

effects to non-target 

vegetation.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 151 of 946

wild relatives.

EPA regulates the use of 

herbicides and has 

concluded that dicamba 

offsite movement from 

labeled uses do not pose 

unreasonable adverse 

effects to non-target 

vegetation.

the dicamba and 

glufosinate traits that 

might be conferred on 

the recipient feral cotton 

or wild relatives. 

EPA regulates the use of 

herbicides and has 

concluded that dicamba 

and glufosinate offsite 

movement from labeled 

uses do not pose 

unreasonable adverse 

effects to non-target 

vegetation.

Gene Flow & 

Weediness

Unchanged Unchanged Unchanged Unchanged

Microorganisms Unchanged Unchanged Unchanged Unchanged

Biodiversity Unchanged Unchanged Unchanged Unchanged

Human Health

Consumer 

Health

Unchanged Unchanged; FDA has 

assessed the safety and 

nutritional characteristics 

of food and feed derived 

from DT soybean and 

concluded that it does 

not differ from 

conventional soybeans. 

EPA has set the 

tolerances of dicamba on 

food and feed to ensure a 

reasonable certainty of 

Unchanged; FDA has 

assessed the safety and 

nutritional characteristics 

of food and feed derived 

from DGT cotton and 

concluded that it does 

not differ from 

conventional cotton. 

EPA has set the 

tolerances of dicamba on 

food and feed to ensure a 

reasonable certainty of 

Unchanged; FDA has 

assessed the safety and 

nutritional characteristics 

of food and feed derived 

from DT soybean and 

DGT cotton and 

concluded that they do 

not differ from 

conventional soybeans 

or cotton. EPA has set 

the tolerances of 

dicamba on food and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 152 of 946

no harm. no harm. feed to ensure a 

reasonable certainty of 

no harm.

Worker Health Use of increased tillage 

may represent a small 

increase in risk for 

workers, as the major 

hazard for agricultural 

workers is injury related 

to machinery. Increased 

use of hand weeding 

represents an increase in 

risks for workers.

Reduced tillage on DT 

soybean acreage could 

have a small beneficial 

impact on workers. 

Decreased reliance on 

hand weeding on DT 

soybean acreage would 

have a positive benefit on 

worker health

Unchanged, or potential 

slight improvement on 

soybean acreage to the 

extent that dicamba may 

reduce the use of 

herbicides with less 

benign toxicity profiles.

Not deregulating DGT 

cotton may result in 

increased tillage and hand 

weeding, which could 

cause adverse impact on 

worker health.

Reduced tillage on DGT 

cotton acreage could 

have a small beneficial 

impact on workers. 

Decreased reliance on 

hand weeding on DGT 

cotton acreage would 

have a positive benefit on 

worker health

Unchanged, or potential 

slight improvement on 

cotton acreage to the 

extent that dicamba may 

reduce the use of 

herbicides with less 

benign toxicity profiles.

Not deregulating DT 

soybean may result in 

increased tillage and hand 

weeding, which could 

cause adverse impact on 

worker health.

Reduced tillage on DT 

soybean and DGT 

cotton acreage could 

have a small beneficial 

impact on workers. 

Decreased reliance on 

hand weeding on DT 

soybean and DGT 

cotton acreage would 

have a positive benefit 

on worker health. 

Unchanged, or potential 

slight improvement on 

soybean and cotton 

acreage to the extent that 

dicamba may reduce the 

use of herbicides with 

less benign toxicity 

profiles.

Animal Feed & Animal 

Health

Unchanged Unchanged; FDA has 

assessed the safety and 

nutritional characteristics 

of food and feed derived 

Unchanged; FDA has 

assessed the safety and 

nutritional characteristics 

of food and feed derived 

Unchanged; FDA has 

assessed the safety and 

nutritional characteristics 

of food and feed derived 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 153 of 946

from DT soybean and 

concluded that it does 

differ from conventional 

soybeans. 

EPA has set the 

tolerances of dicamba on 

food and feed to ensure a 

reasonable certainty of 

no harm.

from DGT cotton and 

concluded that it does 

differ from conventional 

cotton. 

EPA has set the 

tolerances of dicamba on 

food and feed to ensure a 

reasonable certainty of 

no harm.

from DT soybean and 

DGT cotton and 

concluded that they do 

not differ from 

conventional soybeans 

or cotton. 

EPA has set the 

tolerances of dicamba on 

food and feed to ensure 

a reasonable certainty of 

no harm.

Socioeconomic Impacts

Domestic 

Economic 

Environment

The lack of effective 

weed management 

programs combined with 

the potential for 

additional herbicideresistant weeds to develop 

in certain areas in the U.S. 

could adversely impact

the overall profitability 

and sustainability of U.S. 

soybean and cotton 

production.

Unchanged Unchanged Unchanged

Trade Economic 

Environment

Unchanged Unchanged Unchanged Unchanged

Organic and 

Specialty 

Segments

Unchanged Unchanged Unchanged Unchanged

Notes: GT = glyphosate tolerant; GR = glyphosate resistant; GE = genetically engineered; T&E = threatened and endangered; NOP = 

National Organic Program; EIQ = environmental impact quotient
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 154 of 946

IV. ENVIRONMENTAL CONSEQUENCES

This analysis of potential environmental consequences addresses the potential impacts to the 

human environment from the regulatory alternatives discussed in this environmental report. 

Potential environmental impacts from the No Action Alternative and different action alternatives 

for DT soybean and DGT cotton are described in detail throughout this section. 

An environmental impact would be a change, positive or negative, from the existing conditions of 

the affected environment, described for each resource area in Section II. Impacts may be categorized 

as direct, indirect, or cumulative. A direct impact is an effect that results solely from a proposed 

action without intermediate steps or processes. Possible examples include soil disturbance, air 

emissions, and water use. An indirect impact may be an effect that is related to but removed from a 

proposed action by an intermediate step or process. Potential examples include surface water quality 

changes resulting from soil erosion due to increased tillage, and worker safety impacts resulting from 

a change in herbicide use.

The production practices under each alternative determine how the various “resource areas” of the 

affected environment are affected by the decisions of the growers and producers. Those resource 

areas have been grouped into the physical environment (land use, soil, water, and air quality, and 

climate change), biological resources (wildlife and ecosystems), human health, animal health, and 

socioeconomics. For all alternatives discussed in each of the resources areas below, the terms DT 

soybean and DGT cotton are inclusive of the single GE events, any progeny derived from crosses 

between DT soybean or DGT cotton and conventional varieties, and crosses of DT soybean and 

DGT cotton with other GE-derived varieties that have previously been previously deregulated by 

APHIS. 

As discussed elsewhere in this report, Congress transferred regulatory authority over herbicides from 

USDA to EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or herbicide 

resistance, and no authority to consider direct, indirect, or cumulative herbicide impacts under the 

PPA, that may be associated with the deregulation and use of DT soybean or DGT cotton. 

Nonetheless, because APHIS indicated in its Notice of Intent to Prepare an Environmental Impact 

Statement (78 Fed. Reg. 28796, May 16, 2013) that it would be considering herbicide effects and 

herbicide resistance as part of the NEPA process, this document includes a discussion of herbicide 

impacts in the following sections, with more details in an Appendix. Importantly, however, 

Monsanto believes that APHIS has no legal obligation under NEPA to consider direct, indirect, or 

cumulative herbicide impacts or herbicide resistance in any Environmental Impact Statement or 

Environmental Assessment. See DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an 

agency has no ability to prevent a certain effect due to its limited statutory authority over the 

relevant actions, the agency cannot be considered a legally relevant “cause” of the effect, and is 

therefore not required to analyze the environmental impact of an action it could not refuse to 

perform). See also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at 

*16-17 (9th Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not exhibit any 

risk of plant pest harm, APHIS must deregulate it since the agency does not have jurisdiction to 

regulate organisms that are not plant pests.”).

This chapter is organized into nine main sections, as follows:
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 155 of 946

Section IV.A, Methodologies and Assumptions Used in the Analysis, describes the methodology and 

assumptions used in analyses of environmental impacts of DT soybean and DGT cotton.

Section IV.B, Agricultural Production of Soybeans and Cotton, discusses the potential impacts of the No 

Action Alternative and different action alternatives for DT soybean and DGT cotton on how 

soybean and cotton are farmed. The analysis considers potential impacts on crop use and biology, 

land use, agronomic practices, and tillage. The analysis also addresses potential impacts to weed 

management, pest management, and weed resistance, although considered out of scope of the 

authority of USDA as stated above. Section IV.C. also discusses potential impacts on organic 

production, specialty market production, and seed production.

Section IV.C, Physical Environment, discusses the potential impacts of the No Action Alternative and 

different action alternatives for DT soybean and DGT cotton on the physical environment, 

including impacts on land use, soil quality, water quality, air quality and climate change. In addition 

to discussing the potential impacts of the plants themselves, this section also discusses potential 

impacts associated with the use of dicamba, although considered out of scope of the authority of 

USDA as stated above. 

Section IV.D, Biological Resources, discusses the potential impacts of the No Action Alternative and 

different action alternatives for DT soybean and DGT cotton on living organisms in ecological and 

agricultural settings. The biological resources are divided into animal communities, plant 

communities, and microorganisms. Section IV.E also discusses potential impacts related to gene 

flow and weediness, as well as hybridization with cultivated soybean and cotton plants, and 

hybridization with feral species. Section IV.E also considers the impacts on adjacent agricultural 

crops and non-agricultural plants of the offsite movement of herbicides, although considered out of 

scope of the authority of USDA as stated above.

Section IV.E, Human Health, discusses the potential impacts of the No Action Alternative and 

different action alternatives for DT soybean and DGT cotton on consumer and worker health and 

safety. Section IV.F. also addresses potential impacts on human health from the use of pesticides 

that are applied before or during the production of soybean and cotton. Section IV.F. discusses 

potential impacts to human health from the direct ingestion of the products of DT soybean and 

DGT cotton, such as cooking oils, food additives, and nutritional supplements, as well as the 

inhalation of cotton dust by workers during cotton handling and processing.

Section IV.F, Animal Feed and Animal Health, discusses the potential impacts of the No Action 

Alternative and different action alternatives for DT soybean and DGT cotton on animal agriculture, 

and in particular in the animal feed industry. Section IV.G also addresses potential impacts of 

herbicide residues on animal feed, although considered out of scope of the authority of USDA as 

stated above. 

Section IV.G, Socioeconomics, discusses the potential impacts of the No Action Alternative and 

different action alternatives for DT soybean and DGT cotton on the domestic economic 

environments of soybean and cotton and the trade economic environments of soybean and cotton. 

Section IV.H also discusses potential impacts on organic cotton production and organic soybean 

production. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 156 of 946

Section IV.H, Other Impacts and Mitigation Measures discusses other potential impacts associated 

with the implementation of the alternatives, including unavoidable impacts; short-term versus longterm productivity of the environment; and irreversible/irretrievable commitment of resources. The 

section also describes potential mitigation measures, as applicable, beyond what is already built into 

the alternatives.

IV.A. METHODOLOGIES AND ASSUMPTIONS USED IN THE ANALYSIS

IV.A.1. Methodology and Assumptions Used for DT Soybean 

Area of Proposed Use. DT soybean is a crop with a trait that will have intended utility across all of 

the acreage upon which soybean is currently grown and could be widely available in soybean 

varieties sold to growers. 

Over the past decade, glyphosate-tolerant soybean varieties have been widely adopted in the 

marketplace. In most cases, glyphosate was applied to control narrowleaf and broadleaf weeds in 

U.S. soybean fields, where glyphosate provided excellent control of most weeds. In recent years, the 

development, in certain areas of the U.S., of glyphosate-resistant weeds and shifts in broadleaf weed 

populations to species that are inherently more tolerant to glyphosate have increased the use of 

additional herbicides that work through a different mode-of-action to achieve an acceptable level of 

weed control. As a result of the ongoing need to control weed species present in soybean fields, 

additional herbicides are being used, and multiple herbicide-tolerance traits are being developed to 

provide growers with additional weed control options that will compete with DT soybean. If USDA 

were to deregulate DT soybean, these herbicides and traits will likely continue to be available at the 

time DT soybean is introduced to the marketplace; thus, DT soybean would compete for market 

share with established products, like glyphosate-tolerant soybean 40-3-2 first introduced in 1996, 

Roundup Ready 2 Yield soybean, and other new herbicide-tolerance traits that would be available in 

the foreseeable future. Growers will ultimately select weed control systems that fit the needs for 

their individual farming operation, such that some proportion of growers will choose to use DT 

soybean integrated into the glyphosate-tolerant soybean system.

Summary of Genetic Modification. DT soybean was developed through Agrobacterium-mediated 

transformation of conventional soybean tissue based on well-established published methods. DT 

soybean contains a gene from Stenotrophomonas maltophilia that expresses a dicamba mono-oxygenase 

(DMO) protein to confer tolerance to dicamba herbicide. DMO protein rapidly demethylates 

dicamba to the inactive metabolite 3,6-dichlorosalicylic acid (DCSA), a known metabolite of 

dicamba in non-GE soybean, cotton, livestock and soil. The genetic modification is described in 

detail in Appendix G of this Environmental Report.

Basis for Discussion of Pesticide Impacts. As discussed elsewhere in this report, Congress 

transferred regulatory authority over herbicides from USDA to EPA. Accordingly, USDA-APHIS 

has no jurisdiction over herbicides or herbicide resistance, and no authority to consider herbicide 

impacts under the PPA. Nonetheless, because APHIS indicated in its Notice of Intent to Prepare 

an Environmental Impact Statement (78 Fed. Reg. 28796, May 16, 2013) that it would be 

considering herbicide effects and herbicide resistance as part of the NEPA process, Monsanto has 

included a discussion of herbicide impacts in the following section. Importantly, however, 

Monsanto believes that APHIS has no legal obligation under NEPA to consider herbicide impacts 

or herbicide resistance in any Environmental Impact Statement or Environmental Assessment. See
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 157 of 946

DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an agency has no ability to prevent a 

certain effect due to its limited statutory authority over the relevant actions, the agency cannot be 

considered a legally relevant “cause” of the effect, and is therefore not required to analyze the 

environmental impact of an action it could not refuse to perform). See also Center for Food Safety v. 

Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at *16-17 (9th Cir. 2013) (“If APHIS concludes 

that the presumptive plant pest does not exhibit any risk of plant pest harm, APHIS must deregulate 

it since the agency does not have jurisdiction to regulate organisms that are not plant pests.”).. 

Use of Low-Volatility DGA Salt of Dicamba – Proposed Changes in Dicamba Registration: 

Monsanto has submitted to EPA an application to amend EPA Reg. No. 524-582 to register a new 

use pattern for dicamba on DT soybean. The current and proposed uses are summarized in Table

IV.A-1.

In the pending application to EPA, Monsanto requested approval only for the low volatility DGA 

salt formulation of dicamba (U.S. EPA Reg. No. 524-582) for use on DT soybean, and has proposed 

that dicamba applications be limited to ground applications only (i.e., no aerial spraying), as well as 

proposing additional enforceable directions for use. Monsanto has also requested the establishment 

of a tolerance for soybean forage and hay; no other revisions to the dicamba residue tolerances are 

necessary, including animal products such as meat and milk. The use of dicamba on DT soybean

does not present any new environmental exposure scenarios not previously evaluated in the RED 

and deemed acceptable by EPA.

Table IV.A-1. Summary of Dicamba Uses on Soybean

Current Approved Uses Proposed Uses on DT soybean 

Application 

Timing 

Maximum 

Single 

Application 

Rate

(lbs a.e./acre)

Maximum 

Annual 

Application 

Rate

(lbs a.e./acre)

Maximum 

Single 

Application 

Rate

(lbs a.e./acre)

Maximum 

Annual 

Application 

Rate

(lbs a.e./acre)

Preemergence 0.501

2.0

1.02

2.0

Postemergence 

Not labeled

0.50 (V3) 

+ 

0.50 (R1/R2)3

Pre-harvest 

(7 days prior to 

harvest)

1.0 Not labeled

1

 14-28 day planting interval based on product application rate

2

 No planting interval

3

 In-crop application through V3 with a sequential application through R1/R2 growth stage as 

needed. Total of all in-crop applications from emergence up to R1/R2 is 1.0 lb a.e./acre.

Combination with Glyphosate-Tolerant Soybean. DT soybean is intended to be combined with 

glyphosate-tolerant soybean utilizing traditional breeding techniques. Soybean containing both DT 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 158 of 946

soybean and glyphosate tolerance will allow the use of glyphosate and dicamba herbicides in a 

diversified weed management program, which includes the use of residual herbicides or other 

cultural practices, to control a broad spectrum of grasses and broadleaf weed species, and to sustain 

and complement the benefits and value of the glyphosate use in the glyphosate-tolerant systems. 

The combined system will support long-term sustainability of weed management in soybean and, in 

turn, support sustained, economic soybean production.

Inclusion of Potential Impacts from Herbicide Use: As discussed above, it is EPA’s regulatory 

authority under FIFRA to register pesticide products for their intended uses. EPA has sole 

authority to regulate the use of any herbicide. Nonetheless, for the reasons discussed above, this 

environmental report evaluates potential impacts of dicamba use associated with DT soybean on the 

human environment. 

Anticipated Weed Management Recommendations for DT Soybean: Monsanto’s weed 

management system recommendations are shown in(Table IV.A-2. The recommended use patterns 

for dicamba on DT soybean will vary across U.S. soybean growing regions based on differences in 

growth habits and competitiveness of certain glyphosate-resistant weed species. Option 1 would be 

recommended for more aggressive glyphosate-resistant weed species, such as Palmer amaranth 

(Amaranthus palmeri) and waterhemp (Amaranthus rudis). These weed species are very fast growing, 

highly competitive with crops, high seed producers, very densely populated, and germinate and 

emerge throughout the growing season (Fast, et al. 2009; Keeley, et al. 1987; Nordby, et al. 2007; 

Sprague 2012). Two sequential postemergence applications will generally be required to control lateseason emergence of these weed species. However, low rainfall conditions and/or early crop 

canopy closure that can be associated with narrow row spacing of soybean can reduce late-season 

weed emergence and potentially reduce the number of dicamba postemergence applications. Option 

2 would be used for less aggressive glyphosate resistant weed species, such as horseweed (Conyza 

canadensis), common ragweed (Ambrosia artemisiifolia) and giant ragweed (Ambrosia trifida). 

These weed management system recommendations represent a high-end proposal for dicamba use 

associated with DT soybean when combined with glyphosate-tolerant soybean. The actual number 

of applications and timing of applications of dicamba or glyphosate that the grower will make will 

vary depending on the specific weed spectrum, weed infestation levels, and the agronomic situation 

of the individual soybean field. Applying a residual herbicide preemergence in sequence with 

glyphosate plus dicamba postemergence, or tank mixing a residual herbicide with glyphosate plus 

dicamba postemergence could be considered as an alternative to two postemergence applications of 

glyphosate plus dicamba for season long weed control.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 159 of 946

Table IV.A-2. Proposed Weed Management System Recommendations for DT Soybean 

Combined with Glyphosate-Tolerant Soybean. 

Application 

Timing

Conventional Tillage1 Conservation Tillage

(No-till or reduced till) 1

No GR 

Weeds

GR Weeds or 

Suspected GR Weeds2 No GR 

Weeds

GR Weeds or Suspected 

GR Weeds2

Option 14 Option 25 Option 14 Option 25

Preemergence/

Preplant 

Burndown3

Residual Residual Residual

Residual

plus

Glyphosat

e

plus

Dicamba

Residual

plus

Glyphosa

te

plus

Dicamba

Residual

plus

Glyphosate

plus

Dicamba

Postemergence 

1 (V1-V3)

Glyphosa

te

plus

Dicamba

Glyphosa

te

plus

Dicamba

Glyphosa

te

plus

Dicamba

Glyphosat

e

plus

Dicamba

Glyphosa

te

plus

Dicamba

Glyphosate

plus

Dicamba

Postemergence 

2 (V4-R1)

---

Glyphosa

te

plus

Dicamba

--- ---

Glyphosa

te

plus

Dicamba

---

1 Anticipated average rate for dicamba is 0.38 pound a.e. per acre except for fields with glyphosate 

resistant (GR) species where a 0.5 pound a.e. per acre postemergence application rate will be 

recommended in most situations. See Appendix A.

2GR indicates glyphosate-resistant

3 Monsanto and academics recommend the use of soil residuals as part of a comprehensive weed 

resistance management program to ensure that at least two effective herbicide modes-of-action are 

used in soybean and to provide protection against additional resistance development to existing 

herbicides used in soybean production. When a residual plus glyphosate plus dicamba is 

recommended the residual may be applied separately or in tank mixture with glyphosate plus 

dicamba.

4 Option 1 would be used for more aggressive glyphosate resistant weed species, such as Amaranthus

spp.

5 Option 2 would be used for less aggressive glyphosate resistant weed species, such as horseweed.

Potential Additional Dicamba Use. It is impossible to determine the exact amount of acreage on 

which DT soybean may be grown if deregulated. Projections on the annual application of dicamba 

used on DT soybean are based on market adoption rates and the dicamba use pattern on DT

soybean. The maximum possible annual application of dicamba on DT soybean, based on 100% 

adoption of across all U.S. soybean acreage (75 million acres) and applications of dicamba at the 

maximum labeled rates (proposed at 2.0 lbs a.e. per acre per year), would be 150 million pounds 

dicamba (as acid equivalent or a.e.). However, as discussed below, the actual total anticipated

application will be much lower.

For the purposes of this assessment, it is assumed that DT soybean will occupy 40% of the U.S. 

soybean acreage at peak penetration. This estimate is based on a number of factors: 1) the 

percentage of non-glyphosate herbicides currently used in glyphosate-tolerant soybean, 2) current 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 160 of 946

and historical use of dicamba in corn, 3) the development of glyphosate-resistant weeds in soybean 

cultivation areas, 4) the effectiveness of other non-glyphosate herbicides used in glyphosate-tolerant 

soybean, s; and 5) the foreseeable future introduction of new competitive biotechnology-derived 

traits in soybean.

Similarly the anticipated use patterns for dicamba on DT soybean will vary across U.S. soybean

growing regions. This variability is dictated by growth habits and competitiveness of certain 

glyphosate-resistant weed species. As discussed above in Anticipated Weed Management Recommendations 

for DT Soybean, weed management recommendations will vary based on cultivation practices (i.e., 

tillage) and spectrum of glyphosate-resistant weeds present in the field. Based on weed management 

trials conducted across regions and weed spectrum a single early season in-crop application per year 

of dicamba at 0.38 lb a.e. per acre is expected on the majority of DT soybean acres. However, in 

no-till or conservation tillage soybean systems, an additional preplant application at 0.50 lb a.e. per 

acre could also be common practice, and in areas where glyphosate resistant weeds, especially 

Ambrosia and Amaranthus species, are present two in-crop applications at 0.5 lb a.e. each may be 

needed in some situations. See Appendix A for additional information supporting these anticipated

use patterns.

Based on the anticipate dicamba application and use rate analysis summarized above, use of DT 

soybean on 40% of U.S. soybean acres would result in approximately 20.5 million lbs a.e. of dicamba 

applied to DT soybean annually (including preplant, preemergence and in-crop applications), see 

Table IV.A-3 . Currently 233,000 lbs a.e. of dicamba are applied preplant to commercially available 

soybean (Monsanto 2012).

The potential increase in dicamba usage associated with DT soybean production is expected to 

displace, in part, some of the current herbicides used in soybean today. Dicamba offers a relative 

reduction of risk potential in comparison to some of the alternative non-glyphosate herbicides 

currently available to soybean growers (see Appendices E and F) to this environmental report. 

Dicamba could be expected to conservatively replace approximately 21% of the projected total acres 

treated (TAT)49 for all non-glyphosate herbicides used in preplant/preemergence application timing 

and 56% of the projected TAT for all non-glyphosate herbicides used in postemergence application 

timing at peak dicamba use based on a projection that 40% of total planted soybean acres may be 

treated with dicamba following the introduction of DT soybean. At projected peak penetration of 

dicamba use in DT soybean, an increase in both total soybean acres treated and total pounds of nonglyphosate herbicides applied to soybean is projected, however estimated increases are 12% or less 

of the total herbicide use projections if DT soybean is not commercialized.

 

49 The use of TAT provides a way to look at herbicide use that is independent of the various use rates of herbicides. If a herbicide 

is used more than once on an acre the TAT will reflect this multiple use, and consequently the TAT may exceed the number of 

crop acres planted. This provides a more complete view of herbicide use.
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Table IV.A-3. Projected Dicamba Use on DT Soybean 

Dicamba 

Treated 

MON 

87708 

Acres 

Use Scenario (000,000) a

# PRE 

applications

PRE 

application 

rate 

(lb/acre 

a.e.)

# POST 

applications 

(V3 or V3 

& R1)

POST 

application 

rate 

(lb/acre 

a.e.)

Total lbs 

of Dicamba

(000,000)b

Total 

Annual lbs 

of Dicamba 

Maximum labeled use pattern, 100% adoption

75 1 1.0 2 0.50 150 150

Anticipated use pattern, 100% adoption

no-till acres c30 1 0.5 1 0.38 26.4

conventional tillage acresd45 1 0.38 17.1

44

Anticipated use pattern, anticipated peak adoption of dicamba-treated MON 87708 acres

no-till acres c12e1 0.5 1 0.38 10.6

conventional tillage acresd18e1 0.38 6.8

Resistant Amaranthus spp. 

Acresf5

a 2 0.31g

3.1

20.5h

a

See Section Anticipated Weed Management Recommendations for DT Soybean and Appendix A for additional details regarding projected use 

pattern scenarios for dicamba on DT soybean.

b Total lbs dicamba is calculated combining the lbs of dicamba PRE and POST, where the lbs dicamba used either PRE or POST is 

calculated by multiplying the number of applications by the application rate for the respective application timing.

c No-tillage is practiced on 40% of the U.S. soybean acres (CTIC 2007).

d Conventional tillage acres also includes acres where reduced or minimum tillage is practiced and where it is assumed that a preemergent 

application of dicamba will be needed for weed control.

e Monsanto projects dicamba to be used on 40% of U.S. soybean acres (i.e., 30 million acres).

fThese acres are a subset of the no-till and conventional tillage acres.
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g Monsanto anticipates that two POST applications at 0.5 lb/acre a.e. each will be needed on acres resistant with Amaranthus spp. Since 

these acres are a subset of the no-till and conventional tillage acres where a single POST application at 0.38 lb/acre dicamba a.e. has already 

been accounted for, the POST application rate is adjusted to avoid double counting of dicamba use on this subset of acres (i.e., adjusted 

POST application rate = 0.5 lb/acre – (0.38÷2) lb/acre).

h This figure is slightly less than the estimate of 22 million pounds described in Section VIII.H of the petition because it subtracts out the 

single 0.38 lb/acre a.e. application already accounted for in the no-till and conventional tillage calculations.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 163 of 946

IV.A.2. Methodology and Assumptions Used for DGT Cotton

Area of Proposed Use: The DGT cotton herbicide tolerance traits are intended to have utility 

across all of the acreage upon which cotton is currently grown. If deregulated, varieties 

containing DGT cotton would be widely available to cotton growers. 

Summary of Genetic Modification: DGT cotton was developed through Agrobacteriummediated transformation of cotton tissue based on well-established published methods. A 

description of the genetic modification is included in Appendix G to this Environmental 

Report. DGT cotton contains a demethylase gene from Stenotrophomonas maltophilia that 

expresses a dicamba mono-oxygenase (DMO) protein to confer tolerance to dicamba herbicide 

and a bialaphos resistance (bar) gene from Streptomyces hygroscopicus that expresses the 

phosphinothricin N-acetyltransferase [PAT (bar)] protein to confer tolerance to glufosinate 

herbicide. DMO protein rapidly demethylates dicamba to the inactive metabolite 3,6-

dichlorosalicylic acid (DCSA), a known metabolite of dicamba in non-GE cotton, soybean, 

livestock and soil. The PAT (bar) protein acetylates the free amino group of glufosinate to 

produce non-herbicidal N-acetyl glufosinate, a known metabolite in glufosinate-tolerant plants 

(OECD 2002). 

Basis for Discussion of Pesticide Impacts. As discussed elsewhere in this report, Congress 

transferred regulatory authority over herbicides from USDA to EPA. Accordingly, USDAAPHIS has no jurisdiction over herbicides or herbicide resistance, and no authority to consider 

herbicide impacts under the PPA. Nonetheless, because APHIS indicated in its Notice of 

Intent to Prepare an Environmental Impact Statement (78 Fed. Reg. 28796, May 16, 2013) that 

it would be considering herbicide effects and herbicide resistance as part of the NEPA process, 

Monsanto has included a discussion of herbicide impacts in the following section. Importantly, 

however, Monsanto believes that APHIS has no legal obligation under NEPA to consider 

herbicide impacts or herbicide resistance in any Environmental Impact Statement or 

Environmental Assessment. See DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an 

agency has no ability to prevent a certain effect due to its limited statutory authority over the 

relevant actions, the agency cannot be considered a legally relevant “cause” of the effect, and is 

therefore not required to analyze the environmental impact of an action it could not refuse to 

perform). See also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at 

*16-17 (9th Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not exhibit 

any risk of plant pest harm, APHIS must deregulate it since the agency does not have 

jurisdiction to regulate organisms that are not plant pests.”). 

Use of Low-Volatility DGA Salt of Dicamba – Proposed Changes in Dicamba 

Registration: Monsanto has requested a registration from U.S. EPA for the expanded use of a 

low volatility diglycolamine (DGA) salt of dicamba on DGT cotton, limited dicamba 

application to ground application equipment, as well as proposing additional stewardship 

measures. Monsanto plans to further address the use of dicamba on DGT cotton with U.S.

EPA to evaluate whether any additional measures may be appropriate to further address 

potential drift and offsite movement. Monsanto has also requested an increase in the dicamba 

residue tolerance for cottonseed, the establishment of a tolerance for cotton gin by-products, 

and the inclusion of DCSA in the residue definitions for both cottonseed and gin by-products. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 164 of 946

Monsanto submitted an application to EPA to amend Registration number 524-582, a lowvolatility DGA salt formulation, to remove all existing preemergence planting restrictions 

(application intervals, rainfall, and geographic) and to allow in-crop postemergence dicamba 

applications to DGT cotton containing varieties.50 Before any application of dicamba can be 

made onto commercially cultivated DGT cotton, the EPA must first approve a label describing 

the conditions of use of the herbicide on DGT cotton – including the appropriate application 

rates and timing, and other measures necessary to address potential impacts of dicamba drift 

and offsite movement. Dicamba can currently be applied to cotton in the U.S. as a preplant 

application, at least 21 days prior to planting. Following EPA approval of the dicamba label 

amendment, growers would be authorized to apply dicamba alone or in mixtures with 

glyphosate, glufosinate, or other registered herbicides for preplant or postemergence in-crop 

applications on DGT cotton. If the proposed label is approved by EPA, dicamba would be 

authorized to be applied up to 1.0 lb a.e. per acre any time prior to cotton emergence, and 

postemergence in-crop up to 0.5 lbs a.e. per acre per application up through seven days prior to 

harvest. Maximum application amounts for dicamba would be 1.0 lb a.e. per acre for 

preplant/preemergence applications and 0.5 lb a.e. per acre per in-crop application with the 

combined total not to exceed 2.0 lbs a.e. dicamba per year for all applications. The proposed 

application rates on DGT cotton would be less than or equivalent to rates for dicamba 

established for other uses in the dicamba RED including the 2.0 lbs a.e. dicamba per year for all 

applications (U.S. EPA 2009a). Based on Monsanto’s proposed dicamba label, aerial 

applications of dicamba will not be allowed on DGT cotton, thereby reducing spray drift 

potential (BASF 2008). Monsanto has requested a registration from U.S. EPA for the 

expanded use of dicamba on DGT cotton, an increase in the dicamba residue tolerance from 

0.2 ppm to 3 ppm for cottonseed, the establishment of a tolerance of 70 ppm for cotton gin byproducts, and the inclusion of DCSA in the residue definitions for cottonseed and gin byproducts. No other revisions to the dicamba residue tolerances are necessary, including animal 

products such as meat and milk. Furthermore, the use of dicamba on DGT cotton does not 

present any new environmental exposure scenarios not previously evaluated in the RED and 

deemed acceptable by EPA. 

Use of Glufosinate – No Changes in Registration: The PAT (bar) protein acetylates the free 

amino group of glufosinate to produce non-herbicidal N-acetyl glufosinate, a known metabolite 

in glufosinate-tolerant plants (OECD 2002). The use pattern and rate of glufosinate application 

on DGT cotton will follow the existing glufosinate-tolerant cotton uses outlined on the existing 

glufosinate herbicide label (Bayer Crop Science 2007) and Monsanto has confirmed that 

glufosinate residues on DGT cotton treated with commercial glufosinate rates are below the 

established pesticide residue tolerances established by U.S. EPA for both cottonseed and gin 

by-products (40 CFR 180.473). Consequently, Monsanto has not and will not pursue any 

changes in the glufosinate label or the established tolerances for its use on DGT cotton. 

Because there will be no changes in the use pattern and rate of glufosinate on DGT cotton

 

50 The current dicamba label approved by EPA prohibits dicamba preplant application on cotton west of the Rockies due to 

the potential for direct crop injury caused by dicamba in conjuction with the environmental conditions in this area. This 

restriction will not be included on the amended label for application of dicamba on DGT cotton since DGT cotton is 

tolerant to dicamba.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 165 of 946

from the current baseline, these aspects related to the associated use of glufosinate on DGT

cotton are not discussed in detail in this analysis.

Combination with Glyphosate-Tolerant Cotton. DGT cotton is intended to be combined 

with glyphosate-tolerant cotton utilizing traditional breeding techniques. Cotton containing 

both DGT cotton and glyphosate tolerance will allow the use of glyphosate, dicamba, and 

glufosinate herbicides in a diversified weed management program, which includes the use of 

residual herbicides or other cultural practices, to control a broad spectrum of grasses and 

broadleaf weed species, and to sustain and complement the benefits and value of the glyphosate 

use in the glyphosate-tolerant systems. The combined system will support long term 

sustainability of weed management in cotton and, in turn, support sustained, economic cotton 

production.

Use of Multiple Herbicide-Tolerant Traits. In recent years, the development, in certain 

areas of the U.S., of glyphosate-resistant weeds, as well as shifts in broadleaf weed populations 

to species that are inherently more tolerant to glyphosate, have increased the use of nonglyphosate herbicides that work through different modes-of-action to achieve an acceptable 

level of weed control. As a result, multiple herbicide-tolerant traits are and have been 

developed to provide cotton growers with additional weed control options that will compete 

with DGT cotton. These herbicides and traits will be available at the time DGT cotton is 

introduced to the marketplace; thus, DGT cotton will compete for market share with approved 

herbicide tolerance traits, including LibertyLink®, GlyTol®, and TwinLinkcombined-trait 

products, and new herbicide-tolerance traits that will be available in the foreseeable future. 

Growers will ultimately select weed control systems that fit the needs for their individual 

farming operation, such that some proportion of growers will choose to use DGT cottoncontaining varieties integrated into glyphosate-tolerant cotton systems.

Anticipated Weed Management Recommendations for DGT Cotton: The expected use 

patterns for dicamba and glufosinate on DGT cotton will vary across U.S. cotton growing 

regions. This variability is dictated by the environment and weed spectrum variations across 

these regions. Monsanto’s recommendations for the Midsouth and Southeast regions are 

shown in (Table IV.A-4). In these regions, conventional tillage planted acres are expected to 

receive a single in-crop application per season of dicamba at 0.5 lbs a.e. per acre and 

conservation tillage or no-tillage acres are expected to receive two applications (one preplant 

application at 0.375 lbs a.e. per acre and one in-crop application at 0.50 lbs a.e. per acre). All 

acres in this region where glyphosate-resistant weeds are present, regardless of tillage, are 

expected to receive a single in-crop application of glufosinate as 0.53 lbs a.i. per acre. For the 

remaining acres where glyphosate-resistant weeds are not present, glyphosate will likely be used 

for control of late-emerging weeds. Dicamba and glufosinate use in eastern Texas and 

California is expected to be similar to that described for the Midsouth and Southeast regions. 

 



LibertyLink, GlyTol, and TwinLink are registered trademarks of Bayer CropSciences.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 166 of 946

Table IV.A-4. Anticipated Weed Management Recommendations for DGT Cotton

Combined with Glyphosate-Tolerant Cotton Systems for MO, AR, TN, AL, FL, GA, 

NC, SC, VA, LA, MS, eastern TXand CA.1,2

Application 

Timing Conventional Tillage Conservation Tillage (No-till or reduced till)

Preplant burndown 

and/or 

Preemergence 

Residual Dicamba + Glyphosate + 

Residual

Postemergence 1 Dicamba + Glyphosate 

+ Residual3

Dicamba + Glyphosate + 

Residual

Postemergence 2 Glyphosate OR 

Glufosinate4,5

Glyphosate OR Glufosinate 

+ Residual5,6

1 Recommendations modified from those presented in Petition 12-185-01p_a1.

2 Monsanto and academics recommend the use of soil residuals as part of a comprehensive weed resistance 

management program to ensure that two effective herbicide modes-of-action are used in cotton and to provide 

protections against additional resistance development to existing herbicides used in cotton production.

3 Residual recommended if GR weeds present.

4 Glyphosate recommended if no GR weeds present, glufosinate recommended in the presence of GR weeds.

5 Tank mixes of glyphosate and glufosinate will not be recommended, because reduced weed control has been 

observed with the glyphosate and glufosinate tank mix as compared to each individual herbicide (Dotray, et al. 

2011a; Reed et al. 2011; Reed et al. 2012).

6 Glyphosate only if no GR weeds present, glufosinate and residual recommended in the presence of GR weeds.

In western Texas, New Mexico, Kansas, Oklahoma, and Arizona, dicamba is expected to be 

utilized more extensively than glufosinate for management of hard-to-control and/or 

glyphosate-resistant weeds in DGT cotton. Glufosinate is considered less effective on the 

weed spectrum under the high temperature and low humidity environmental conditions in these 

regions (Bayer CropScience 2011). The recommendations for these cotton growing areas are 

shown in Table IV.A-5. All acres are expected to receive one preplant application of dicamba 

(0.375 lbs a.e. per acre). Areas with glyphosate-resistant weeds are also expected to receive two 

in-crop applications of dicamba (0. 50 lbs a.e./acre) per season, whereas areas without 

glyphosate-resistant weeds will only receive one in-crop application of dicamba (0.50 lbs 

a.e./acre). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 167 of 946

Table IV.A-5. Anticipated Weed Management Recommendations for DGT Cotton

Combined with Glyphosate-Tolerant Cotton Systems for western TX, NM, KS, OK, and 

AZ 1,2

Application Timing Conventional Tillage Conservation Tillage 

(No-till or reduced till)

Preplant burndown 

and/or Preemergence 

Dicamba + Glyphosate 

+ Residual

Dicamba + Glyphosate 

+ Residual

Postemergence 1 Dicamba + Glyphosate Dicamba + Glyphosate 

Postemergence 2 Glyphosate ± Dicamba3 Glyphosate ± Dicamba3

1 Recommendations modified from those presented in Petition 12-185-01p_a1.

2 Monsanto and academics recommend the use of soil residuals as part of a comprehensive 

weed resistance management program to ensure that two effective herbicide modes-of-action 

are used in cotton and to provide protections against additional resistance development to 

existing herbicides used in cotton production.

3 Dicamba recommended when GR weeds present.

Inclusion of Potential Impacts from Herbicide Use: As discussed above, it is EPA’s 

regulatory authority under FIFRA to register pesticide products for their intended uses. EPA 

has sole authority to regulate the use of any herbicide. Nonetheless, for the reasons discussed 

above, this environmental report evaluates potential impacts of dicamba use associated with 

DGT cotton on the human environment. Glufosinate will not be discussed in detail because 

glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and will be considered baseline. 

Potential Additional Dicamba Use: The maximum possible annual application of dicamba 

on cotton, with 100% adoption of DGT cotton across all U.S. upland cotton acreage (14.8 

million acres)51 and applications of dicamba at the maximum labeled rates (proposed at 2.0 lbs 

a.e. per acre per year), would be 29.6 million pounds a.e. However, as discussed below, the 

actual total anticipated application will be much lower and will not likely be additive with the 

current application of herbicides currently used on cotton, as dicamba will displace some of the 

current herbicide usage in cotton.

As discussed above, in the Midsouth, and Southeast regions, conventional tillage-planted acres 

are expected to receive a single in-crop application per season of dicamba at 0.5 lbs a.e. per acre 

and conservation tillage or no-tillage acres are expected to receive two applications (one 

preplant application at 0.375 lbs a.e. per acre and one in-crop application at 0.50 lbs a.e. per 

acre). Dicamba use in East Texas and California is expected to be similar to that described for 

 

51 Based on approximately 14.8 million acres planted to cotton in 2011, see Table II.B-12.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 168 of 946

the Midsouth and Southeast regions. In West Texas, Kansas, Oklahoma, New Mexico, and 

Arizona dicamba is expected to be utilized more extensively than glufosinate for management 

of troublesome and/or glyphosate-resistant weeds. Glufosinate is considered less effective on 

the weed spectrum under the high temperature and low humidity environmental conditions in 

these regions (Bayer CropScience 2011). In West Texas, Kansas, Oklahoma, New Mexico, and 

Arizona conventional tillage acres are expected to receive two in-crop applications of dicamba 

per season at 0.50 lbs a.e. per acre. No-till or conservation tillage cotton acres will realistically 

receive three applications per season (one preplant application at 0.375 lbs a.e. per acre and two 

in-crop applications at 0.50 lbs a.e. per acre. Assuming these anticipated applications and use 

rates of dicamba, and using the assumption that DGT cotton has 100% adoption across all U.S. 

cotton acres and conservation tillage systems are used on approximately 21% of the U.S. cotton 

acres (CTIC 2008), dicamba use on DGT cotton would total approximately 10.5 million 

pounds. 

It is impossible to determine the exact amount of acreage on which DGT cotton may be grown 

if deregulated. A 100% adoption rate of DGT cotton among cotton growers is unrealistic. 

Monsanto estimates dicamba-treated acres could eventually reach 50% of the total U.S. cotton 

acres. Growers will ultimately select weed control systems that fit the needs for their individual 

farming operations such that some proportion of growers will choose to use DGT cotton

integrated into the glyphosate-tolerant cotton systems. As discussed in Section II.B.2.d, 

growers produced herbicide-tolerant cotton on approximately 73% of U.S. cotton acres in 

2011, with almost all of this cotton being glyphosate-tolerant and approximately 3% being 

glufosinate tolerant. Growers currently producing herbicide-tolerant cotton are the growers 

most likely to adopt DGT cotton. Some of these growers may continue to grow the currentlyavailable types of herbicide-tolerant cotton, and use other herbicides for hard-to-control weeds. 

For example, approximately 53 to 64% of growers of glyphosate-tolerant cotton used a nonglyphosate herbicide in addition to glyphosate in their cotton crops in 2005 (Givens et al. 

2009a). An additional factor influencing the number of dicamba-treated cotton acres in the 

future will be the introduction of competing herbicide-tolerant traits in cotton. 

Based on the dicamba application and use rate analysis summarized above, use of DGT cotton

on 50% of U.S. cotton acres would result in approximately 5.2 million lbs a.e. of dicamba 

applied to DGT cotton annually (including preplant, preemergence and in-crop applications). 

Currently 364,000 lbs a.e. of dicamba are applied preplant to commercially available cotton 

(Monsanto 2012).

It is anticipated that dicamba applications will continue for all other currently labeled crops at 

the current annual level of approximately 3.8 million pounds (Monsanto 2012). Therefore, the 

addition of the estimated 5.2 million pounds of dicamba that would be applied to DGT cotton

would result in a total estimated U.S. dicamba use of approximately 9.0 million pounds 

annually. This does not include the additional amount from DT soybean (Section IV.A.1).

The potential increase in dicamba usage associated with DGT cotton production is expected to 

displace a number of the current herbicides used in cotton today, particularly applications of 

fluometuron, fomesafen, MSMA, and paraquat. Dicamba offers a relative reduction of risk 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 169 of 946

potential in comparison to some of the alternative non-glyphosate herbicides currently available 

to cotton growers (see Appendices E and F. Dicamba could be expected to conservatively 

replace approximately 34% of the projected total acres treated (TAT)52 for all non-glyphosate 

herbicides used in preplant/preemergence application timing and 37% of the projected TAT 

for all non-glyphosate herbicides used in postemergence application timing at peak dicamba use 

based on a projection that 50% of total planted cotton acres may be treated with dicamba 

following the introduction of DGT cotton. At projected peak penetration of dicamba use in 

DGT cotton an increase in both total cotton acres treated and total pounds of non-glyphosate 

herbicide active ingredient applied to cotton is projected, however estimated increases are 16% 

or less of the total herbicide use projections (16% for TAT and 12% of total pounds of active 

ingredient) if DGT cotton is not commercialized. 

IV.B. AGRICULTURAL PRODUCTION OF SOYBEANS & COTTON

IV.B.1. Crop Use and Biology

IV.B.1.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially cultivated (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. Under this alternative DT soybean and DGT cotton would not become integrated 

into the glyphosate-tolerant soybean and cotton systems, respectively, and dicamba use would 

likely remain similar to today’s use pattern in soybean and cotton. Adding alternative herbicides 

with different modes-of-action into the glyphosate-tolerant systems to manage the development 

of glyphosate-resistant weeds and control glyphosate-resistant weeds would continue to remain 

an option. Additionally, conventional tillage may increase in some instances as an additional 

means to control problematic weeds. 

Currently herbicides are used on nearly all (~98%) soybean acres, and over 35 different 

herbicide active ingredients are registered and available for use by soybean growers to control 

weeds. (See Section II.B.1.d); herbicides are used on nearly all (>99%) cotton acres, and 

approximately 39 million pounds of 30 different herbicides are applied pre- or postemergence 

in cotton production (Monsanto 2012) (See Section II.B.2.d). The use of herbicides in soybean 

and cotton production is expected to continue to increase as more growers adopt, in certain 

areas of the U.S., diversified weed management strategies to combat hard-to-control and 

herbicide-resistant weeds. Some of the available herbicides may pose greater potential risks to 

humans, and wildlife than dicamba; and conventional tillage practices may increase. Increased 

use of tillage could have a small adverse impact on wildlife, as the crop residues that remain 

with the use of conservation tillage may provide shelter and food for wildlife, such as game 

birds and small animals, and soil erosion associated with tillage can increase sedimentation and 

turbidity in surface water bodies and impact aquatic wildlife (CTIC 2011).

 

52 The use of TAT provides a way to look at herbicide use that is independent of the various use rates of herbicides. If a 

herbicide is used more than once on an acre the TAT will reflect this multiple use, and consequently the TAT may exceed 

the number of crop acres planted. This provides a more complete view of herbicide use.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 170 of 946

IV.B.1.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes to crop use and biology. 

The Deregulation in Whole Alternatives would be the gradual integration of the 

dicamba-tolerant event DT soybean with the current glyphosate-tolerant soybean systems using 

traditional breeding techniques. As discussed in Section IV.B.1, under the Deregulation in 

Whole Alternative, the cultivation of DT soybean is not expected to impact soybean agronomic 

practices, with the exception of a change in herbicide use pattern. Cultivation of DT soybean 

would not alter agronomic inputs or the number of soybean acres under cultivation, and will 

help maintain current levels of conservation tillage adoption and may have a small positive 

effect on the use of conservation tillage. 

Potential Impacts from the Genetic Modification. Potential impacts from dietary exposure 

to DT soybean are discussed in detail in Sections IV.E.1 and IV.F. All the information in 

Sections IV.E.1 and IV.F.1 is relevant to dietary exposure for any animal that may consume DT 

soybean. As discussed in those sections, there is no meaningful risk to animal or human health 

from dietary exposure to the MON 87708 DMO protein and there are no known toxic 

properties associated with MON 87708 DMO protein. Furthermore, the seed produced by DT 

soybean is compositionally equivalent to commercially cultivated soybean, whether or not it is 

treated with dicamba. This information on the safety of MON 87708 DMO protein and the 

composition of DT soybean seed and forage, as detailed in Appendices F and H to this 

environmental report, indicate that the effects to mammals that consume DT soybean forage or 

seed would be no different than those from the consumption of commercially cultivated 

soybean. Similarly, the impact to birds or other animals, including migratory birds and animals 

that may consume soybean forage or seed from DT soybean would be no different than 

possible impacts from commercially cultivated soybean. During field trials with DT soybean, 

no biologically relevant changes in arthropod feeding damage were observed (see Appendix G)

indicating similar arthropod susceptibility for DT soybean compared to commercially cultivated 

soybean. DT soybean exhibits no differences in toxic effects on insects or other animals as 

compared to commercially cultivated soybean. In addition, the cultivation of DT soybean does 

not impact the nutritional quality, safety, or availability of animal feed derived from DT 

soybean (see Section IV.F.). 

Potential Impacts from Dicamba. To support the introduction of DT soybean, Monsanto 

has submitted to EPA an application to amend EPA Reg. No. 524-582, a low-volatility DGA 

salt formulation, to register a new use pattern for dicamba on DT soybean. The current and 

proposed uses are summarized in Table IV.A-1 (see Section IV.A.1). However, a 

comprehensive safety evaluation and risk assessment conducted by EPA concluded that 

dicamba has low toxicity to mammals, is not a carcinogen, does not adversely affect 

reproduction and development, and does not bioaccumulate in mammals (U.S. EPA 2009a; d). 

Similarly, an ecotoxicological risk assessment concluded that the use of dicamba does not pose 

an unreasonable risk of adverse effects to non-target species, such as birds and fish, when used 

according to label directions, nor does it pose an unreasonable risk of adverse effects to insects 

outside of the application area (U.S. EPA 2009a; d). Furthermore, outside the cultivated 

soybean field, dicamba is unlikely to affect forbs and beneficial arthropods that are dependent 

on plants for survival (U.S. EPA 2009a; d). 
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In summary, in terms of potential impacts to animal communities, including insects, beneficial 

arthropods, and all other animals that live in or near soybean fields containing DT soybean, the 

difference between the No Action and Deregulation in Whole Alternatives is primarily the 

difference in the types of herbicides that may be used. EPA has determined that when 

herbicides are used in accordance with their labels, no unreasonable adverse impacts will result. 

As discussed above, EPA’s conclusions are based on comprehensive safety evaluations and risk 

assessments. Compared to the Deregulation in Whole Alternative, the No Action Alternative 

may pose a small increase in adverse impact on animal communities if it results in increased 

tillage, as crop residue provides shelter and food for wildlife, such as game birds and small 

animals, and soil erosion associated with tillage can increase sedimentation and turbidity in 

surface water bodies and impact aquatic wildlife (CTIC 2011).

IV.B.1.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed in Section IV.B.1.a, the No Action Alternative for DT soybean is not expected to 

result in significant changes to crop use and biology. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. As discussed 

in IV.B.2, the cultivation of DGT cotton is not expected to impact cotton agronomic practices, 

with the exception of a change in herbicide use pattern. Cultivation of DGT cotton would not 

alter agronomic inputs or the number of cotton acres under cultivation, and will help maintain 

current levels of conservation tillage adoption and may have a small positive effect on the use 

of conservation tillage. 

Potential Impacts from the Genetic Modification. Potential impacts from dietary exposure 

to DGT cotton are discussed in detail in Sections IV.E.1 and IV.F. Except for the discussion 

specific to cottonseed oil and linters in Section IV.F.2, all the information in Sections IV.E.1 

and IV.F is relevant to dietary exposure for any animals that may consume DGT cotton. As 

discussed in those sections, there is no meaningful risk to animal or human health from dietary 

exposure to MON 88701 DMO or PAT (bar). There are no known toxic properties associated 

with MON 88701 DMO or PAT (bar). Furthermore, the seed produced by DGT cotton is 

compositionally equivalent to commercially cultivated cotton, whether or not it is treated with 

dicamba and/or glufosinate. This information on the safety of MON 88701 DMO and PAT 

(bar) and composition of DGT cottonseed, as detailed Appendices F and H to this 

environmental report, indicate that the effects to mammals that consume DGT cotton seed 

would be no different than those possible from the consumption of commercially cultivated 

cotton. Similarly, the impact to birds or other animals, including migratory birds and animals 

that may consume cotton forage or cottonseed from DGT cotton would be no different than 

possible impacts from commercially cultivated cotton. During field trials with DGT cotton, no 

biologically relevant changes in arthropod feeding damage were observed (see Appendix G)

indicating similar arthropod susceptibility for DGT cotton compared to commercially 

cultivated cotton. DGT cotton exhibits no differences in toxic effects on insects or other 

animals as compared to commercially cultivated cotton. In addition, the cultivation of DGT 

cotton does not impact the nutritional quality, safety, or availability of animal feed derived from 

DGT cotton (see Section IV.F). 
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Potential Impacts from Dicamba. To support the introduction of DGT cotton, Monsanto 

has submitted an application to EPA to amend Registration number 524-582, a low-volatility 

DGA salt formulation, to remove all preemergence planting restrictions (application intervals, 

rainfall, and geographic) and to allow in-crop postemergence dicamba applications to DGT 

cotton. However, a comprehensive safety evaluation and risk assessment conducted by EPA 

concluded that dicamba has low toxicity to mammals, is not a carcinogen, does not adversely 

affect reproduction and development, and does not bioaccumulate in mammals (U.S. EPA 

2009a; d). Similarly, an ecotoxicological risk assessment concluded that the use of dicamba 

does not pose an unreasonable risk of adverse effects to non-target species, such as birds and 

fish, when used according to label directions, nor does it pose an unreasonable risk of adverse 

effects to insects outside of the application area (U.S. EPA 2009a; d). Furthermore, outside the 

cultivated cotton field, dicamba is unlikely to affect forbs and beneficial arthropods that are 

dependent on plants for survival (U.S. EPA 2009a; d). 

Glufosinate has been used over-the-top of glufosinate-tolerant crops since 1995. Glufosinate is 

currently labeled for in-crop application with glufosinate-tolerant cotton from emergence 

through early bloom growth stage. The use pattern and rate of glufosinate on DGT cotton will 

follow the existing glufosinate-tolerant cotton uses outlined on the glufosinate herbicide label.

In summary, in terms of potential impacts to animal communities, including insects, beneficial 

arthropods, and all other animals that live in or near cotton fields containing DGT cotton, the 

difference between the No Action and Deregulation in Whole Alternatives is primarily the 

difference in the types of herbicides that may be used. EPA has determined that when 

herbicides are used in accordance with their labels, no unreasonable adverse impacts will result. 

As discussed above, EPA’s conclusions are based on comprehensive safety evaluations and risk 

assessments. Compared to the Deregulation in Whole Alternative, the No Action Alternative 

may pose a small increase in adverse impact on animal communities if it results in increased 

tillage, as crop residue provides shelter and food for wildlife, such as game birds and small 

animals, and soil erosion can increase sedimentation and turbidity in surface water bodies and 

impact aquatic wildlife, and soil erosion associated with tillage can increase sedimentation and 

turbidity in surface water bodies and impact aquatic wildlife (CTIC 2011).

IV.B.1.d. Approval in Whole of DT Soybean and DGT Cotton. 

As discussed in detail above, in terms of potential impacts to animal communities, including 

insects, beneficial arthropods, and all other animals that live in or near soybean and cotton 

fields containing DT soybean / DGT cotton, the difference between the No Action and 

Deregulation in Whole Alternatives is primarily the difference in the types of herbicides that 

may be used. EPA has determined that when herbicides are used in accordance with their 

labels, no unreasonable adverse impacts will result. As discussed above, EPA’s conclusions are 

based on comprehensive safety evaluations and risk assessments. Further discussion of the 

difference in the types of herbicides used and associated impacts is included at Appendix A. 

Compared to the Deregulation in Whole Alternative for DT Soybean and DGT Cotton, the No 

Action Alternative may pose a small increase in adverse impact on animal communities if it 

results in increased tillage, as crop residue provides shelter and food for wildlife, such as game 

birds and small animals, and soil erosion can increase sedimentation and turbidity in surface 

water bodies and impact aquatic wildlife, and soil erosion associated with tillage can increase 

sedimentation and turbidity in surface water bodies and impact aquatic wildlife (CTIC 2011). 
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IV.B.2. General Agronomic Practices

IV.B.2.a. No Action Alternative for Both DT Soybean and DGT Cotton. 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially cultivated (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. General agronomic practices such as planting and harvesting times, crop nutrition, 

use of plant growth regulators, and preharvest and harvest practices are expected to remain the 

same as described in Section II.B.1.c. Specialized agronomic practices such as row spacing, the 

use of cover crops and crop rotation practices, as well as adoption of precision agriculture may 

change over time. There is a potential for increased use of non-glyphosate herbicides and 

potential increased use of tillage for weed control or hand-weeding. There may be increased 

potential for development of herbicide-resistant weeds in certain areas of the U.S.

IV.B.2.b. Approval in Whole of DT Soybean, but not DGT Cotton.

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes in general agronomic practices except for a potential for increased use of 

non-glyphosate herbicides and potential increased use of tillage or hand-weeding for weed 

control. There may be increased potential for development of herbicide-resistant weeds in 

certain areas of the U.S. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with the current 

glyphosate-tolerant soybean systems using traditional breeding techniques. As discussed in 

Appendix G, with the exception of the tolerance to dicamba, DT soybean is phenotypically and 

agronomically unchanged from other commercially cultivated soybean. No impact on 

agronomic practices and attributes such as planting and harvesting times, crop nutrition, use of 

plant growth regulators, preharvest and harvest practices, row spacing, use of cover crops, crop 

rotation, yield and introduction of new varieties would be anticipated. Therefore, the 

Deregulation in Whole and No Action Alternatives are the same regarding their potential 

impact on general agronomic practices, with the exception of potential increased use of nonglyphosate herbicides and increased use of tillage or hand-weeding for weed control under the 

No Action Alternative. There may also be increased potential for development of herbicideresistant weeds in certain areas of the U.S. under the No Action Alternative.

IV.B.2.c. Approval In Whole of DGT Cotton, but not DT Soybean

As discussed above, under the No Action Alternative for DT soybean, there is a potential for 

increased use of non-glyphosate herbicides and potential increased use of tillage or handweeding for weed control. There may be increased potential for development of herbicideresistant weeds in certain areas of the U.S.

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. As discussed 

in Appendix G, with the exception of the tolerances to both dicamba and glufosinate, DGT 

cotton is phenotypically and agronomically unchanged from other commercially cultivated 
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cotton. No impact on agronomic practices and attributes such as planting and harvesting times, 

crop nutrition, use of plant growth regulators, preharvest and harvest practices, row spacing, 

use of cover crops, crop rotation, yield and introduction of new varieties would be anticipated. 

Therefore, the Deregulation in Whole and No Action Alternatives are the same regarding their 

potential impact on general agronomic practices, with the exception of potential increased use 

of non-glyphosate herbicides and increased use of tillage or hand-weeding for weed control 

under the No Action Alternative. There may also be increased potential for development of 

herbicide-resistant weeds in certain areas of the U.S. under the No Action Alternative.

IV.B.2.d. Approval In Whole of DT Soybean and DGT Cotton.

As discussed above, the difference between the No Action and the Deregulation in Whole 

Alternatives would be the gradual integration of the dicamba-tolerant event DT soybean with 

the current glyphosate-tolerant soybean systems using traditional breeding techniques, and of 

dicamba and glufosinate-tolerant event DGT cotton with the current glyphosate-tolerant cotton 

systems using traditional breeding techniques. As discussed in Appendix G, with the exception 

of the tolerance to both dicamba (and glufosinate in the case of DGT cotton) DT soybean and 

DGT cotton are phenotypically and agronomically unchanged from other commercially 

cultivated soybean and cotton. No impact on agronomic practices and attributes such as 

planting and harvesting times, crop nutrition, use of plant growth regulators, preharvest and 

harvest practices, row spacing, use of cover crops, crop rotation, yield and introduction of new 

varieties would be anticipated. Therefore, the Deregulation in Whole of DT soybean and DGT 

cotton and No Action Alternatives are the same regarding their potential impact on general 

agronomic practices, with the exception of potential increased use of non-glyphosate herbicides 

and increased use of tillage or hand-weeding for weed control under the No Action Alternative. 

There may also be increased potential for development of herbicide-resistant weeds in certain 

areas of the U.S. under the No Action Alternative. 

IV.B.3. Tillage 

IV.B.3.a. No Action Alternative for Both DT Soybean and DGT Cotton. 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially available (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. Soybean and cotton growers will not have access to DT soybean and DGT cotton 

and some combination of herbicides already used in soybean and cotton production acres, in 

certain areas of the U.S., and possibly increased tillage or hand-weeding may be used to control 

problematic weeds, including glyphosate-resistant weeds. Increased tillage would negate many 

of the benefits of conservation tillage to soil including improvement of soil structure, reduction 

of soil compaction, conservation of soil moisture, reduction of soil erosion and the inherent 

benefits to water resources, and improvement of soil organic matter content (CTIC 2011; U.S. 

EPA 2008c). 

IV.B.3.b. Approval In Whole of DT Soybean, but Not DGT Cotton.

As discussed above, under the No Action Alternative for DGT cotton, it is possible that 

increased tillage or hand-weeding may be used to control problematic weeds, including 

glyphosate-resistant weeds. Increased tillage would negate many of the benefits of conservation 
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tillage to soil including improvement of soil structure, reduction of soil compaction, 

conservation of soil moisture, reduction of soil erosion and the inherent benefits to water 

resources, and improvement of soil organic matter content (CTIC 2011; U.S. EPA 2008c). 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with the current 

glyphosate-tolerant soybean systems using traditional breeding techniques. DT soybean would 

allow the additional use of dicamba herbicide in a diversified weed management program to 

control a broad spectrum of grasses and broadleaf weed species, including glyphosate-resistant 

biotypes of Palmer amaranth, marestail, common ragweed, giant ragweed, and waterhemp. The 

availability of DT soybean should help preserve the current acreage of soybean grown using 

conservation tillage and potentially help increase conservation tillage acreage. As discussed in 

Appendix B, increases in total soybean acres dedicated to conservation tillage have been 

attributed to an increased use of herbicide-tolerant soybean that reduces the need for 

mechanical weed control. Dicamba would provide additional modes-of-action for managing 

herbicide-resistant species. Therefore, the Deregulation in Whole Alternative would better 

sustain and potentially increase the use of conservation tillage practices as compared to the No 

Action Alternative.

IV.B.3.c. Approval In Whole of DGT Cotton, but Not DT Soybean.

As discussed above, under the No Action Alternative for DT soybean, it is possible that 

increased tillage may be used to control problematic weeds, including glyphosate-resistant 

weeds. Increased tillage would negate many of the benefits of conservation tillage to soil 

including improvement of soil structure, reduction of soil compaction, conservation of soil 

moisture, reduction of soil erosion and the inherent benefits to water resources, and 

improvement of soil organic matter content (CTIC 2011; U.S. EPA 2008c). 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. DGT cotton

would allow the additional use of dicamba herbicide in a diversified weed management program 

to control a broad spectrum of grasses and broadleaf weed species, including glyphosateresistant biotypes of Palmer amaranth, marestail, common ragweed, giant ragweed, and 

waterhemp. The availability of DGT cotton should help preserve the current acreage of cotton 

grown using conservation tillage and potentially help increase conservation tillage acreage, and 

reduce need for hand-weeding. As discussed in Appendix B, increases in total cotton acres 

dedicated to conservation tillage have been attributed to an increased use of herbicide-tolerant 

cotton that reduces the need for mechanical weed control. Dicamba would provide additional 

modes-of-action for managing herbicide-resistant species. Therefore, the Deregulation in 

Whole Alternative would better sustain and potentially increase the use of conservation tillage 

practices as compared to the No Action Alternative.

IV.B.3.d. Approval In Whole of DT Soybean and DGT Cotton.

As discussed above, Deregulation in Whole of DT soybean and DGT cotton would result in 

the gradual integration of the dicamba-tolerant event DT soybean and the dicamba and 

glufosinate-tolerant event DGT cotton with the current glyphosate-tolerant soybean systems 

using traditional breeding techniques. DT soybean and DGT cotton would allow the additional 
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use of dicamba herbicide (and glufosinate in the case of cotton) in a diversified weed 

management program to control a broad spectrum of grasses and broadleaf weed species, 

including glyphosate-resistant biotypes of Palmer amaranth, marestail, common ragweed, giant 

ragweed, and waterhemp. The availability of DT soybean and DGT cotton should help 

preserve the current acreage of soybean and cotton grown using conservation tillage and 

potentially help increase conservation tillage acreage. As discussed in Appendix B, increases in 

total soybean and cotton acres dedicated to conservation tillage have been attributed to an 

increased use of herbicide-tolerant soybean and cotton that reduce the need for mechanical 

weed control or hand-weeding. Dicamba would provide additional modes-of-action for 

managing herbicide-resistant species. Therefore, the Deregulation in Whole Alternatives would 

better sustain and potentially increase the use of conservation tillage practices as compared to 

the No Action Alternative.

IV.B.4. Pest Management

IV.B.4.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially available (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. While specific diseases and pests in soybean and cotton change in significance over 

time and geography, the general management practices summarized in Section II.B.1.c would 

be expected to continue under the No Action Alternative.

IV.B.4.b. Approval of DT Soybean, but not DGT Cotton

As discussed above, under the No Action Alternative for DGT cotton, general pest 

management practices would be expected to continue under the No Action Alternative. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with the current glyphosatetolerant soybean systems using traditional breeding techniques. As discussed in Appendix G, 

with the exception of the tolerance to dicamba, DT soybean is phenotypically, agronomically 

and compositionally unchanged from other commercially cultivated soybean. Phenotypic and 

agronomic information collected from field trials in 2008 using the same agricultural inputs 

showed no biologically meaningful differences between DT soybean and the conventional 

control. In an individual-site assessment of disease damage conducted in the field trials, no 

differences were observed between DT soybean and the conventional control for any of the 

comparisons for the assessed diseases among all observations across the U.S. In an assessment 

of arthropod-related damage, no statistically significant differences (5% level of significance) 

were detected between DT soybean and the conventional control for any of the comparisons 

for the assessed arthropods. See Appendix G for details. The lack of significant biological 

differences in plant responses to disease damage and arthropod-related damage for DT soybean 

support the conclusion that the Deregulation in Whole Alternative is the same as the No 

Action Alternative in terms of impacts on disease and pest management.
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IV.B.4.c. Approval of DGT Cotton, but not DT Soybean

As discussed above, under the No Action Alternative for DT soybean, general pest 

management practices would be expected to continue under the No Action Alternative. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. As discussed 

in Appendix G, with the exception of the tolerances to both dicamba and glufosinate, DGT 

cotton is phenotypically, agronomically and compositionally unchanged from other 

commercially cultivated cotton. Phenotypic and agronomic information collected from field 

trials conducted in 2010 using the same agricultural inputs showed no biologically meaningful 

differences between DGT cotton and the conventional control. In an individual-site 

assessment of disease damage conducted in the 2010 field trials, no differences were observed 

between DGT cotton and the conventional control for any of the comparisons for the assessed 

diseases among all observations across the U.S. In an assessment of arthropod-related damage, 

no statistically significant differences (5% level of significance) were detected between DGT 

cotton and the conventional control for any of the 288 comparisons for the assessed 

arthropods. See Appendix G for details. The lack of significant biological differences in plant 

responses to disease damage and arthropod-related damage for DGT cotton support the 

conclusion that the Deregulation in Whole Alternative is the same as the No Action Alternative 

in terms of impacts on disease and pest management.

IV.B.4.d. Approval in Whole of DT Soybean and DGT Cotton

As discussed above, field trials demonstrate that are no significant biological differences in plant 

responses to disease damage and arthropod-related damage in DT soybean and DGT cotton as 

compared to conventional controls. Thus, the Deregulation in Whole Alternative for DT 

soybean and DGT cotton is the same as the No Action Alternative in terms of impacts on 

disease and pest management.

IV.B.5. Weed Management

IV.B.5.a. No Action Alternative for DT Soybean and DGT Cotton

Under the No Action Alternative, DT soybean would continue to be regulated by APHIS. 

Under this alternative DT soybean combined with glyphosate-tolerant soybean would not be 

available. Growers would continue to cultivate available GE and non-GE soybean, using 

glyphosate alone or in combination with other non-glyphosate herbicides used in soybean 

production for weed management, and/or incorporating mechanical tillage into their cultural 

practices. Under this alternative dicamba herbicide would not become integrated into the 

glyphosate-tolerant soybean system and dicamba use would likely remain similar to today’s use 

pattern in soybean. Growers would continue to use the glyphosate-tolerant soybean system for 

broad spectrum weed control, other registered non-glyphosate herbicides alone or in 

combination with other herbicide-tolerant soybean for management of hard-to-control and/or 

glyphosate-resistant weeds, and/or incorporate tillage into their practices. Some non-glyphosate 

alternative herbicides have a less benign human health and environmental profile compared to 

dicamba, and reduced agronomic flexibility due to soybean planting restrictions, rotational crop 
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planting restrictions, the need for adequate soil moisture for activation, and the need to apply 

prior to planting to minimize crop injury (See Section II.B.1.d for additional information).53 

Integration of DT soybean into the glyphosate-tolerant soybean system has the potential to 

mitigate the evolution and development of herbicide-resistant weeds (see Appendix B for 

additional detail). The use of dicamba in conjunction with glyphosate and other residual 

herbicides provides growers with an herbicide system with two to three different modes of 

action with activity on the major target weeds including biotypes with resistance to glyphosate. 

Thus, it is foreseeable that under the No Action Alternative, the inability to integrate DT 

soybean into the glyphosate-tolerant soybean system could increase the potential for 

glyphosate-resistant weed populations to evolve and spread in soybean producing areas in 

certain parts of the U.S. In addition, the potential for resistance to evolve and spread in certain 

parts of the U.S. for other herbicides used in soybean production could also potentially increase 

in these areas where growers do not use multiple modes-of-action or other weed management 

methods. Also under the No Action Alternative, increased use of other non-glyphosate 

alternative herbicides, some with a less benign human health and environmental characteristics 

compared to dicamba, and reduced flexibility for the grower (e.g., restricted plant-back 

intervals, rotational crop restrictions) would be expected (Tables II.B-7 and II.B-8). A number 

of weeds commonly found in the Midwestern and southern portions of the U.S. already display 

resistance to many of these alternative herbicides (Tables II.B-9 and II.B-10), while only four 

broadleaf weed species have been confirmed to be resistant to dicamba in North the 

U.S./Canada, even though dicamba has been widely in use for over 40 years. Increasing the 

number of weed management options available to soybean growers, including other herbicide 

tolerant traits pending deregulation, is an important element to mitigate evolution and 

development of resistant weed populations.

Given these observations, the No Action Alternative for DT soybean and corresponding lack

of effective alternative modes of action may lead to an increase in weed resistant populations 

for these alternative herbicides in some areas of the U.S. Herbicides are a critical element of 

conservation tillage practices. Since weed management is a primary reason for tillage, herbicides 

are the primary tool to replace tillage and thus are critical to the sustainability of conservation 

tillage practices. Under the No Action Alternative, increased use of traditional tillage methods 

for management of hard-to-control and/or glyphosate-resistant weeds may occur in some 

situations and result in the potential loss of many of the benefits of conservation tillage.

Growers would continue to use the glyphosate-tolerant soybean system for broad spectrum 

weed control, other registered non-glyphosate herbicides, including dicamba, alone or in 

combination with other herbicide-tolerant soybean for management of hard-to-control and/or 

glyphosate-resistant weeds, and/or incorporate tillage into their practices. 

 

53 As previously discussed, all alternative herbicides used in soybean production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human 

health or environmental profile compared to some alternative herbicides in the same risk category (e.g., aquatic plant risk). 

In other instances dicamba presents a similar risk potential compared to some alternatives. In a few cases, dicamba 

presents a greater risk potential compared to some alternatives. This comparative assessment serves to demonstrate that 

the use of dicamba on DT soybean is unlikely to result in a significant impact/risk to human health or the environment 

compared to current herbicide agronomic practices, and in some instances its use may impart additional benefits as 

described in this Environmental Report.
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Under the No Action Alternative, DGT cotton would continue to be regulated by APHIS. 

Under this alternative DGT cotton combined with glyphosate-tolerant cotton would not be 

available. Growers would continue to cultivate available GE and non-GE cotton, using 

glyphosate alone or in combination with other non-glyphosate herbicides used in cotton 

production, including glufosinate, for weed management, and/or incorporating mechanical 

tillage or hand-weeding into their cultural practices. Dicamba will continue to be applied 

preplant for control of broadleaf weeds. The use of alternative non-glyphosate herbicides,

tillage practices or hand-weeding is expected to continue to increase as growers in certain areas 

of the U.S. seek additional herbicide or cultural options to manage hard-to-control and/or 

herbicide-resistant weeds in their fields (CAST 2012; Sosnoskie and Culpepper 2012). While all 

pesticides must meet the FIFRA standard ensuring that they do not pose unreasonable adverse 

effects to humans or the environment before they can be registered, some non-glyphosate 

alternative herbicides have less favorable human health and environmental characteristics 

compared to dicamba, and may have more restrictive application requirements or use rates to 

mitigate human health or environmental hazards. In addition, some non-glyphosate alternative 

herbicides have reduced agronomic flexibility due to cotton planting restrictions, rotational crop 

planting restrictions, the need for adequate soil moisture for activation, and the need to apply 

prior to planting or with hooded sprayers in-crop to minimize crop injury, as compared to 

dicamba. (See Section II.B.2.d and Appendix A for additional information.).

54 Growers in 

certain parts of the U.S. would continue to experience weed control challenges with hard-tocontrol and resistant weed species, such as morningglory and glyphosate-resistant Palmer 

amaranth; the number of acres with resistant weeds is projected to increase due to lack of 

adequate weed control solutions (Hartzler 2013; Owen 2006). Growers will continue to use 

alternative non-glyphosate herbicides that do not provide consistent or adequate control of 

resistant broadleaf weeds, likely leading to the development, in certain areas of the U.S., of new 

resistant weed populations to alternative herbicides such as glufosinate, ALS inhibitors and 

PPO inhibitors (Prostko 2011b; Sosnoskie and Culpepper 2012) (Dr. Larry Steckel and Dr. 

Stanley Culpepper, personal communications, August 2012). The lack of effective weed 

management programs combined with the potential for additional herbicide-resistant weeds to 

develop in certain areas in the U.S. can adversely impact the overall profitability and 

sustainability of U.S. cotton production (Culpepper, et al. 2008; Jordan et al. 2011; Nichols et al. 

2010). Growers would continue to use the glyphosate-tolerant cotton system for broad 

spectrum weed control, other registered non-glyphosate herbicides, including dicamba, alone or 

in combination with other herbicide-tolerant cotton for management of hard-to-control and/or 

glyphosate-resistant weeds, and/or incorporate tillage or hand-weeding into their practices. 

 

54 As previously discussed, all alternative herbicides used in cotton production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human 

health or environmental profile compared to some alternative herbicides in the same risk category (e.g., aquatic plant risk). 

In other instances dicamba presents a similar risk potential compared to some alternatives. In a few cases, dicamba 

presents a greater risk potential compared to some alternatives. This comparative assessment serves to demonstrate that 

the use of dicamba on DGT cotton is unlikely to result in a significant impact/risk to human health or the environment 

compared to current herbicide agronomic practices, and in some instances its use may impart additional benefits as 

described in this Environmental Report.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 180 of 946

IV.B.5.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, Under the No Action Alternative, DGT cotton combined with glyphosatetolerant cotton would not be available. Growers would continue to cultivate available GE and 

non-GE cotton, using glyphosate alone or in combination with other non-glyphosate herbicides 

used in cotton production, including glufosinate, for weed management, and/or incorporating 

mechanical tillage or hand-weeding into their cultural practices. Dicamba will continue to be 

applied preplant for control of broadleaf weeds. The use of alternative non-glyphosate 

herbicides or tillage practices/hand-weeding is expected to continue to increase as growers in 

certain areas of the U.S. seek additional herbicide or cultural options to manage hard-to-control 

and/or herbicide-resistant weeds in their fields (CAST 2012; Sosnoskie and Culpepper 2012). 

Some non-glyphosate alternative herbicides have a less benign human health and the 

environment profile compared to dicamba, and reduced agronomic flexibility due to cotton 

planting restrictions, rotational crop planting restrictions, the need for adequate soil moisture 

for activation, and the need to apply prior to planting or with hooded sprayers in-crop to 

minimize crop injury (See Section II.B.2.d and Appendix A for additional information).55 

Cotton growers in certain areas of the U.S. would continue to experience weed control 

challenges with hard-to-control and resistant weed species, such as morningglory and 

glyphosate-resistant Palmer amaranth; the number of acres with resistant weeds is projected to 

increase due to lack of adequate weed control solutions (Hartzler 2013; Owen 2006). Cotton 

growers will continue to use alternative non-glyphosate herbicides that do not provide 

consistent or adequate control of resistant broadleaf weeds, likely leading to the development, 

in certain areas of the U.S., of new resistant weed populations to alternative herbicides such as 

glufosinate, ALS inhibitors and PPO inhibitors (Prostko 2011b; Sosnoskie and Culpepper 2012)

(Dr. Larry Steckel and Dr. Stanley Culpepper, personal communications, August 2012). The 

lack of effective weed management programs combined with the potential for additional 

herbicide-resistant weeds to develop in certain areas in the U.S. can adversely impact the overall 

profitability and sustainability of U.S. cotton production (Culpepper et al. 2008; Jordan et al. 

2011; Nichols et al. 2010).

With respect to DT soybean, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba-tolerant event DT soybean 

with the current glyphosate-tolerant soybean systems using traditional breeding techniques. DT 

soybean would allow the expanded use of dicamba in a diversified weed management program 

to control a broad spectrum of grasses and broadleaf weed species including glyphosateresistant biotypes of Palmer amaranth, marestail, common ragweed, giant ragweed and 

waterhemp. Under the Deregulation in Whole Alternative, soybean growers will have the 

option to cultivate soybean containing the combination of dicamba and glyphosate tolerance 

traits.

Under the Deregulation in Whole Alternative, soybean growers would have the option of a 

wider window for treating their soybean crop with dicamba pending U.S. EPA approval of the 

 

55 As previously discussed, all alternative herbicides used in cotton production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human 

health or environmental profile compared to some alternative herbicides in the same risk category (e.g., aquatic plant risk).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 181 of 946

new use pattern. As discussed in detail in Section IV.A.1, Monsanto submitted an application 

to U.S. EPA to amend Registration number 524-582, a low-volatility DGA salt formulation, to 

remove all existing preemergence planting restrictions and to allow in-crop postemergence 

dicamba applications to DT soybean. Before any application of dicamba can be made onto 

commercially cultivated DT soybean, the EPA must first approve a label describing the 

conditions of use of the herbicide in connection with DT soybean – including the appropriate 

application rates and timing, and other measures necessary to address potential impacts of 

dicamba offsite movement. The number of acres upon which dicamba is used will likely 

increase under this alternative. As described in Section IV.A.1, DT soybean could eventually 

occupy 40% of U.S. soybean acres at peak penetration. The potential use of dicamba on DT

soybean would result in a total of 50.2 million acres treated with dicamba. Similarly, the total 

amount of dicamba applied in overall agriculture would also increase. Based upon an upper-end 

estimation of the anticipated commercial use pattern for dicamba in DT soybean, an additional 

20.5 million pounds of dicamba is estimated (high-end) to be added to U.S. soybean fields each 

season. According to NASS statistics, approximately 103 million pounds of herbicides were 

used on soybean in 2006, and more recently 133 million pounds of herbicides in 2012, 

demonstrating the trend towards increasing herbicide use for the management of problematic 

weeds including resistant populations as well as the incorporation of diversified weed 

management practices in soybean growing areas (USDA-NASS 2012d). As discussed 

previously, dicamba will displace in part the use of some existing herbicides used in soybean 

production.

Dicamba has a more benign human health and environmental profile in comparison to some of 

the alternative non-glyphosate herbicides currently available to soybean growers. The rationale 

and supporting information for the comparative alternative analysis is summarized below, 

additional details are presented in Appendices A:

Dicamba has a more favorable toxicity profile and poses a lower health risk potential to 

applicators and consumers compared to some alternative herbicides;

Dicamba has lower toxicity to aquatic animals and plants and poses lower risk potential to 

aquatic organisms compared to some alternative herbicides;

Dicamba when used in conjunction with glyphosate integrated into the glyphosate-tolerant 

soybean system provides growers with a more flexible and reliable weed management system 

(Peterson, et al. 2011).

Dicamba could be expected to conservatively replace approximately 14% of the projected total 

acres treated (TAT) for all non-glyphosate herbicides used in preplant/preemergence 

application timing and 15% of the projected TAT for all non-glyphosate herbicides used in 

postemergence application timing at peak dicamba use based on the 40% of total planted 

soybean acres where dicamba is projected to be used. At projected peak penetration of 

dicamba use in DT soybean an increase in both total acres treated and total pounds of herbicide 

active ingredient applied is projected, however estimated increases are 12% or less of the total 

herbicide use projections (11% for TAT and 12% of total pounds of active ingredient) if DT 

soybean is not commercialized. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 182 of 946

Dicamba is an excellent option to mitigate the potential for development of resistance to other 

herbicides because of its broad activity on broadleaf weeds and low level of weed resistance, 

specifically on the summer spectrum of weeds known to infest soybean acres. 

In summary, with the cultivation of DT soybean and the associated use of dicamba, shifts in 

herbicide use will occur, with dicamba displacing some of the alternative herbicides currently 

used by growers. Conservation tillage practices are expected to be sustained and potentially 

increase, and the DT soybean system will provide soybean growers with a more flexible and 

reliable weed management options. On the basis of the above analysis, the Deregulation in 

Whole and No Action Alternatives are similar regarding weed management for soybean 

growers. However, the No Action Alternative would not provide as many options to manage 

weeds and address the potential for the development of herbicide-resistant weeds, and would 

not take advantage of DT soybean to help sustain the long-term agronomic, environmental, and 

economic value and benefits of glyphosate as a weed control tool in soybean.

IV.B.5.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, under the No Action Alternative, DT soybean would continue to be 

regulated by APHIS. Under this alternative DT soybean combined with glyphosate-tolerant 

soybean would not be available. Growers would continue to cultivate available GE and nonGE soybean, using glyphosate alone or in combination with other non-glyphosate herbicides 

used in soybean production for weed management, and/or incorporating mechanical tillage 

into their cultural practices. Under this alternative dicamba herbicide would not become 

integrated into the glyphosate-tolerant soybean system and dicamba use would likely remain 

similar to today’s use pattern in soybean. Growers would continue to use the glyphosatetolerant soybean system for broad spectrum weed control, other registered alternative 

herbicides alone or in combination with other herbicide-tolerant soybean for targeted hard-tocontrol weeds, and/or incorporate tillage into their practices. 

Integration of DT soybean into the glyphosate-tolerant soybean system has the potential to 

mitigate the evolution and development of glyphosate- and other herbicide-resistant weeds (see 

Appendix B for additional detail). For soybean, the use of dicamba in conjunction with 

glyphosate and other residual herbicides provides growers with an herbicide system with two to 

three different modes of action with activity on the major target weeds including biotypes with

resistance to glyphosate. Thus, it is foreseeable that under the No Action Alternative, the 

inability to integrate DT soybean into the glyphosate-tolerant soybean system could increase, in 

certain areas of the U.S., the potential for glyphosate-resistant weed populations to evolve and 

spread in soybean producing areas. In addition, the potential for resistance to evolve and spread 

for other herbicides used in soybean production could also increase in these areas where 

growers do not use multiple modes-of-action or other weed management methods. Also under 

the No Action Alternative, increased use of other non-glyphosate alternative herbicides, some 

with a less benign human health and environmental profile compared to dicamba, and reduced 

flexibility for the grower (e.g., restricted plant-back intervals, rotational crop restrictions) would 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 183 of 946

be expected (See Section II.B.1.d and Appendices A & B).

56 A number of weeds commonly 

found in the Midwestern and southern portions of the U.S. already display resistance to many 

of these alternative herbicides (Tables II.B-9 and II.B-10), while only four broadleaf weed 

species have been confirmed to be resistant to dicamba in the U.S./Canada, even though 

dicamba has been widely in use for over 40 years. Increasing the number of weed management 

options available to soybean growers, including other herbicide tolerant traits pending 

deregulation, is an important element to mitigate evolution and development of resistant weed 

populations.

Given these observations, the No Action Alternative for DT soybean and corresponding lack 

of effective alternative modes of action may, in some areas of the U.S., lead to an increase in 

weed resistant populations for these alternative herbicides. Herbicides are a critical element of 

conservation tillage practices. Since weed management is a primary reason for tillage, herbicides 

are the primary tool to replace tillage and thus are critical to the sustainability of conservation 

tillage practices. Under the No Action Alternative for DT soybean, increased use of traditional 

tillage methods for the control of problematic weeds may occur in some situations and result in 

the potential loss of many of the benefits of conservation tillage.

With respect to cotton, the difference between the No Action and the Deregulation in Whole 

Alternatives would be the gradual integration of the dicamba and glufosinate-tolerant event 

DGT cotton with the current glyphosate-tolerant cotton systems using traditional breeding 

techniques. DGT cotton would allow the expanded use of dicamba, along with glufosinate 

herbicide in a diversified weed management program to control a broad spectrum of grasses 

and broadleaf weed species including glyphosate-resistant biotypes of Palmer amaranth, 

marestail, common ragweed, giant ragweed and waterhemp. Under the Deregulation in Whole 

Alternative growers will have the option to cultivate cotton containing the combination of 

dicamba, glufosinate, and glyphosate tolerance traits. Monsanto is not seeking changes to the 

current labeled use pattern for glufosinate with glufosinate-tolerant cotton, thus the 

deregulation of DGT cotton will only result in changes in the dicamba use pattern on cotton. 

For those acres where glyphosate-resistant broadleaf weeds may already be present and where 

dicamba could be used for control of resistant or hard-to-control broadleaf weeds, the 

cultivation of cotton containing the DGT cotton traits would be a new option for growers. 

With the exception of its tolerance to both dicamba and glufosinate, DGT cotton has been 

shown to be no different from commercially available (both GE and non-GE) cotton in its 

agronomic characteristics. A summary of current cotton agronomic practices is presented in 

Section II.B.2.c.

 

56 All alternative herbicides used in soybean production can be used safely, and do not pose an unreasonable risk to humans 

or the environment. Nonetheless, in some instances dicamba has a more benign human health or environmental profile

compared to some alternative herbicides in the same risk category (e.g., aquatic plant risk). In other instances dicamba 

presents a similar risk potential compared to some alternatives. In a few cases, dicamba presents a greater risk potential 

compared to some alternatives. This comparative assessment serves to demonstrate that the use of dicamba on DT 

soybean is unlikely to result in a significant impact/risk to human health or the environment compared to current 

herbicide agronomic practices, and in some instances its use may impart additional benefits as described in this 

Environmental Report.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 184 of 946

The cultivation of DGT cotton combined with glyphosate tolerant cotton will provide growers 

with the ability to use dicamba, glufosinate and glyphosate as part of an effective diversified

weed management system. Dicamba tolerance provides an important tool for the management 

of hard-to-control and resistant weed species, in particular glyphosate-resistant Amaranthus 

species such as Palmer amaranth, which pose major weed control challenges in cotton 

production and threaten cotton quality and yield (CAST 2012). Soil residual herbicides will 

continue to be recommended by academics and Monsanto, especially in fields where 

glyphosate-resistant Amaranthus species such as Palmer amaranth and waterhemp may be 

present to aid in the control of these weed species, which are prolific seed producers, fast 

growing, highly competitive with cotton, densely populated, and germinate and emerge 

throughout the growing season (Chandi, et al. 2013; Jha 2008; Liu, et al. 2012; New Mexico 

State University 2013; Nordby et al. 2007; Sosnoskie et al. 2011). Dicamba, when used in 

conjunction with DGT cotton combined with glyphosate-tolerant cotton and proper 

management practices, would provide growers with a more flexible and reliable weed 

management system (Marshall 2012; York, et al. 2012). Combining DGT cotton with 

glyphosate-tolerant cotton would allow for in-season application of glyphosate, glufosinate, 

and/or dicamba, and increase the diversity of in-crop herbicide control options which, in turn, 

supports the long term sustainability of glyphosate-tolerant cotton. 

In addition, the availability of DGT cotton combined with glyphosate-tolerant cotton is 

expected to help preserve the current acreage of cotton grown using conservation tillage and 

potentially help increase conservation tillage acreage. As discussed in Section II.B.2.c, 3.1.3, 

increases in total acres dedicated to conservation tillage have been attributed to an increased use 

of herbicide-tolerant cotton which reduces the need for mechanical weed control, such as tillage 

and hand-weeding (McClelland et al. 2000; Towery and Werblow 2010). 

Under the Deregulation in Whole Alternative, growers would have expanded dicamba use 

options pending U.S. EPA approval of the new use pattern. As discussed in detail in Section 

IV.A.2, Monsanto submitted an application to U.S. EPA to amend Registration number 524-

582, a low-volatility DGA salt formulation, to remove all existing preemergence planting 

restrictions (application intervals, rainfall, and geographic) and to allow in-crop postemergence 

dicamba applications to DGT cotton. Before any application of dicamba can be made onto 

commercially cultivated DGT cotton, the EPA must first approve a label describing the 

conditions of use of the herbicide in connection with DGT cotton – including the appropriate 

application rates and timing, and other measures necessary to address potential impacts of 

dicamba offsite movement. As described in Section IV.A.2, the number of cotton acres treated 

with dicamba will likely increase under this Alternative; Monsanto estimates as much as 50% of 

cotton acres could eventually be treated with dicamba herbicide. Based on the analysis 

described in Section IV.A.2., use of DGT cotton on 50% of U.S. cotton acres would result in 

approximately 5.2 million lbs a.e. of dicamba applied to DGT cotton annually (including 

preplant, preemergence and in-crop applications). Currently 364,000 lbs a.e. of dicamba are 

applied preplant to commercially available cotton (Monsanto 2012). With this potential 

addition of dicamba applied to DGT cotton, the total U.S. dicamba use is estimated to be 9.0 

million pounds annually. 

In comparison, approximately 39 million pounds of herbicides were used on over 99% of 

cotton acres in 2011 (see Section II.B.2.d), and herbicide usage in cotton has been trending up 

due to the growth and spread of problematic weeds, including herbicide-resistant populations 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 185 of 946

and the implementation of diversified weed management practices (see Section II.B.2.d and 

Appendix A for additional details regarding recent trends). Additionally, dicamba will displace 

the use of some existing herbicides used in cotton production, which may have a less benign

human health and the environment profile compared to dicamba.

57 In addition, many of the 

registered alternative herbicides are limited by application restrictions, plant back restrictions, 

the need for adequate soil moisture for activation, and the need to apply prior to planting or 

with hooded sprayers in-crop to minimize crop injury (See Tables II.B-179 and II.B-2018 for 

additional information). 

Dicamba could be expected to conservatively replace approximately 34% of the projected total 

acres treated (TAT) for all non-glyphosate herbicides used in preplant/preemergence 

application timing and 37% of the projected TAT for all non-glyphosate herbicides used in 

postemergence application timing at peak dicamba use based on the 50% of total planted 

cotton acres where dicamba is projected to be used. At projected peak penetration of dicamba 

use in DGT cotton an increase in both total acres treated and total pounds of herbicide active 

ingredient applied is projected, however estimated increases are 16% or less of the total 

herbicide use projections (16% for TAT and 12% of total pounds of active ingredient) if DGT 

cotton is not commercialized. 

In summary, with the cultivation of DGT cotton and the associated use of dicamba, shifts in 

herbicide use will occur, with dicamba displacing some of the alternative herbicides currently 

used by growers. Conservation tillage practices are expected to be sustained and potentially 

increase, and the DGT cotton system will provide cotton growers with a more flexible and 

reliable weed management options. On the basis of the above analysis, the Deregulation in 

Whole and No Action Alternatives are similar regarding weed management for cotton growers. 

However, the No Action Alternative would not provide as many options to manage weeds and 

address the development of herbicide-resistant weeds, and would not take advantage of DGT 

cotton to help sustain the long-term agronomic, environmental, and economic value and 

benefits of glyphosate as a weed control tool in cotton.

IV.B.5.d. Approval in Whole of DT Soybean and DGT Cotton

As discussed above, the cultivation of DT soybean and DGT cotton and the associated use of 

dicamba, shifts in herbicide use will occur, with dicamba displacing some of the alternative 

herbicides currently used by growers. Conservation tillage practices are expected to be 

sustained and potentially increase, and the DT soybean and DGT cotton systems will provide 

growers with a more flexible and reliable weed management options. On the basis of the above 

analysis, the Deregulation in Whole and No Action Alternatives are similar regarding weed 

 

57 All alternative herbicides used in soybean production can be used safely, and do not pose an unreasonable risk to humans 

or the environment. Nonetheless, in some instances dicamba has a more benign human health or environmental profile

compared to some alternative herbicides in the same risk category (e.g., aquatic plant risk). In other instances dicamba 

presents a similar risk potential compared to some alternatives. In a few cases, dicamba presents a greater risk potential 

compared to some alternatives. This comparative assessment serves to demonstrate that the use of dicamba on DT 

soybean is unlikely to result in a significant impact/risk to human health or the environment compared to current 

herbicide agronomic practices, and in some instances its use may impart additional benefits as described in this 

Environmental Report.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 186 of 946

management for cotton growers. However, the No Action Alternative would not provide as 

many options to manage weeds and address the development of herbicide-resistant weeds, and 

would not take advantage of DGT cotton to help sustain the long-term agronomic, 

environmental, and economic value and benefits of glyphosate as a weed control tool in cotton. 

Additional discussion of weed management impacts is set forth at Cumulative Impacts Section 

V.I. and Appendix B.

IV.B.6. Weed Resistance

IV.B.6.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Under this alternative, DT soybean and DGT cotton combined with 

glyphosate-tolerant soybean would not be available. Growers would continue to cultivate 

available herbicide-tolerant GE and non-GE soybean and cotton, using glyphosate alone or in 

combination with other non-glyphosate herbicides (including glufosinate) for weed 

management. 

Growers would continue to use the glyphosate-tolerant soybean system for broad spectrum 

weed control, other registered alternative herbicides alone or in combination with other 

herbicide-tolerant soybean, and/or incorporate tillage into their practices. The use of existing

herbicide options presents increasing challenges to the grower’s ability to achieve consistent 

control of problematic weeds such as glyphosate-resistant waterhemp and Palmer amaranth. It 

is foreseeable that under the No Action Alternative, there is a potential for an increase in the 

evolution and development of glyphosate-resistant weed populations in soybean cultivation 

areas, as well as the potential for the evolution and development of resistant populations to 

other alternative herbicides used in soybean production (see Appendix B for additional details).

With respect to cotton, the use of existing herbicides presents challenges to the grower’s ability 

to effectively achieve consistent control of problematic weeds in cotton such as Palmer 

amaranth. Thus, it is foreseeable that under the No Action Alternative, the inability to cultivate 

cotton varieties containing DGT cotton combined with the glyphosate tolerance trait could 

increase the potential for glyphosate-resistant weed populations to evolve and spread in certain 

cotton producing areas of the U.S. In addition, the potential for resistance to continue to 

evolve and spread for other popular herbicides used in cotton production, such as ALS and 

PPO herbicides, could also increase in these areas where growers do not use multiple effective 

modes of action (Prostko 2011a) (Dr. Larry Steckel and Dr. Stanley Culpepper, personal 

communications, August 2012). 

Monsanto and the weed scientist community recommend the use of multiple herbicide modesof-action in herbicide-tolerant soybean and cotton systems regardless of whether glyphosateresistant or hard to control broadleaf weeds are present (Jordan et al. 2011; Monsanto 

Company 2012a; Price et al. 2011; Prostko 2011b; University of Tennessee 2012). These 

options include the use of residual and postemergence herbicides such as microtubule 

inhibitors (pendimethalin, trifluralin), PPO inhibitors (flumioxazin, fomesafen), long chain fatty 

acid inhibitors (metolachlor), synthetic auxins (2,4-D, dicamba), ALS inhibitors 

(thifensulfuron), and PSII inhibitors (metribuzin, sulfentrazone- soybean; diuron, fluometuron, 

prometryn- cotton). Monsanto’s Roundup Ready PLUS program, which encourages soybean 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 187 of 946

and cotton growers to use multiple herbicide modes-of-action in their weed management 

programs, will continue under the No Action Alternative. 

Academics recommend that all cotton acres in the South and Midsouth be treated as though 

there are existing glyphosate-resistant Palmer amaranth weed populations present (University of 

Georgia 2012; University of Tennessee 2012). This is because the spread of glyphosate 

resistance alleles via outcrossing among Palmer amaranth populations is highly probable. 

Additionally, a number of weeds commonly found in the cotton production areas of the U.S. 

already display resistance to several alternative non-glyphosate herbicides used in cotton 

production, which are commonly recommended to control glyphosate-resistant Amaranthus 

species, specifically the ALS and PPO inhibitors. In the absence o a diversified weed 

management system that employs multiple herbicide modes-of-action, new resistant weed 

biotypes, including biotypes resistant to multiple herbicides, are likely to evolve and increase 

leading to fewer herbicide options available for control of key weed species in cotton. The 

more extensive use and, in some situations, use in the absence of other herbicide modes-ofaction effective at controlling Palmer amaranth, raises the risk level for additional resistance to 

develop. In addition, a number of current herbicides used in cotton today are limited by 

application restrictions, plant back restrictions, the need for adequate soil moisture for 

activation, and the need to apply prior to planting or with hooded sprayers in-crop to minimize 

crop injury (See Appendices A & B for additional details).

The evolution and development of resistance to alternative herbicides can be mitigated through 

the use of diversified weed resistance management strategies that utilize different mechanisms 

of control as part of weed management practices, such as mechanical tillage or other cultural 

practices.

IV.B.6.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, it is foreseeable that under the No Action Alternative, the inability to 

cultivate cotton varieties containing DGT cotton combined with the glyphosate tolerance trait 

could increase the potential for glyphosate-resistant weed populations to evolve and spread in 

certain cotton producing areas of the U.S. In addition, the potential for resistance to continue 

to evolve and spread for other popular herbicides used in cotton production, such as ALS and 

PPO herbicides, could also increase in these areas where growers do not use multiple effective 

modes of action (Prostko 2011a) (Dr. Larry Steckel and Dr. Stanley Culpepper, personal 

communications, August 2012).

With respect to DT soybean, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba-tolerant event DT soybean 

with the current glyphosate-tolerant soybean systems using traditional breeding techniques. For 

those acres where glyphosate-resistant broadleaf weeds may already be present and where 

dicamba could be used for control of resistant or hard-to-control broadleaf weeds, the 

cultivation of soybean containing the DT soybean traits would be an option for growers. DT 

soybean combined with glyphosate-tolerant soybean would provide the tools to directly manage 

the development of glyphosate- and other herbicide-resistant weeds (see Section II.B.2.d and 

Appendices B and C for more detail). The use of dicamba in conjunction with glyphosate and 

residual herbicides provides growers with an effective herbicide system with two to three 

distinct modes-of-action with activity on the major target weeds including biotypes with 

resistance to glyphosate. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 188 of 946

To support the introduction of varieties containing DT soybean, Monsanto will use multiple 

methods to distribute technical and stewardship information to growers, academics and grower 

advisors regarding the use of the product as part of a diversified weed management system. 

Growers who purchase Monsanto varieties containing DT soybean sign a limited use license 

known as the Monsanto Technology Stewardship Agreement (MTSA). The MTSA obligates

growers to comply with certain requirements, including the Monsanto Technology Use Guide 

(TUG). The TUG will set forth the requirements and best practices for the cultivation of DT 

soybean including recommendations on weed resistance management practices. 

The weed resistance management practices that are designed to minimize the potential for the 

development of herbicide-resistant weeds will be articulated in the TUG and also be broadly 

communicated to growers and retailers. These practices will be communicated through a 

variety of means, including direct communications to each grower authorized to purchase and 

plant a soybean variety containing DT soybean, a public website, and reports in farm media 

publications. The overall weed resistance management program will be reinforced through 

collaborations with U.S. academics, who will provide their recommendations for appropriate 

stewardship of dicamba and glyphosate in soybean production, as well as by collaboration with 

crop commodity groups who have launched web-based weed resistance educational modules. 

Dicamba has been used extensively on millions of acres for over 40 years. To date, there are 

four species with known resistant biotypes to dicamba in the U.S./Canada: common 

hempnettle, kochia, prickly lettuce, and wild mustard (Heap 2012a). Additionally, a population 

of common lambsquarters has been confirmed to be resistant in New Zealand, for a total of 

five species worldwide with confirmed resistant biotypes to dicamba. See Appendix B for 

additional information on dicamba-resistant biotypes. However, the introduction of DT 

soybean is not likely to result in a substantial risk for the development of dicamba-resistant 

weeds for several reasons: 

 The use of glyphosate in addition to dicamba would provide multiple herbicide modesof-action on key broadleaf weeds which would diminish the chance for selection of 

dicamba-resistant broadleaf weeds when species are not resistant to glyphosate; 

 In fields where glyphosate-resistant broadleaf weeds are present or suspected, 

glyphosate plus dicamba will be recommended. In addition, Monsanto will recommend 

an additional herbicide with a 3rd mode-of-action that also has activity on the 

glyphosate-resistant broadleaf weed, thereby providing two effective modes-of-action to 

control glyphosate-resistant weeds; and 

 The proposed dicamba herbicide label for DT soybean, existing glyphosate herbicide 

labels, and separate Monsanto weed management recommendations (e.g., Monsanto’s 

annual TUG and publicly available websites) will specify the effective rate and timing of 

dicamba and glyphosate applications for optimal weed control, reducing the selection 

pressure for dicamba as well as glyphosate. The new use pattern and draft label for 

dicamba to be used on DT soybean are subject to regulatory approval by EPA.

DT soybean integrated into the glyphosate-tolerant cotton systems provides a simple, effective 

weed management system to control existing resistant weeds and allows for an easy way to 

incorporate multiple effective herbicide modes-of-action for effective weed resistance 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 189 of 946

management. In the unlikely case that broadleaf weeds were to evolve or develop with 

resistance to dicamba, existing cultivation and alternative herbicide tools (see Section II.B.2.d 

for a description of alternative herbicides) would remain potential options to provide effective 

control (see Appendix A for a description of alternative herbicides). Furthermore, under the 

Deregulation in Whole Alternative, the potential for resistance to continue to evolve and spread 

for other popular herbicides used in soybean production, such as ALS and PPO herbicides, is 

expected to be reduced. However, the development of resistance to alternative herbicides can 

be managed through the use of diversified weed resistance management strategies that utilize 

different mechanisms of control as part of weed management practices, such as mechanical 

tillage or other cultural practices. On the basis of the above analysis, the Deregulation in Whole 

and No Action Alternatives are similar regarding potential increased costs and complexity in 

weed control for soybean growers. However, the No Action Alternative would not provide as 

many management options for addressing the development of herbicide-resistant weeds, and 

would not take advantage of DT soybean to help sustain the long-term agronomic, 

environmental and economic value and benefits of glyphosate-tolerant soybean.

IV.B.6.c. Approval in Whole of DGT Cotton, but not DT Soybean 

Under the No Action Alternative, DT soybean would continue to be regulated by APHIS. 

Under this alternative DT soybean combined with glyphosate-tolerant soybean would not be 

available. Growers would continue to cultivate available herbicide-tolerant GE and non-GE 

soybean, using glyphosate alone or in combination with other non-glyphosate herbicides for 

weed management. Growers would continue to use the glyphosate-tolerant soybean system for 

broad spectrum weed control, other registered alternative herbicides alone or in combination 

with other herbicide-tolerant soybean, and/or incorporate tillage into their practices. There is a 

potential for glyphosate-resistant weed populations to increase and spread in soybean 

cultivation areas, as well as the potential for the development and spread of resistant 

populations to other alternative herbicides used in soybean production.

With respect to DGT cotton, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba and glufosinate-tolerant 

event DGT cotton with the current glyphosate-tolerant cotton systems using traditional 

breeding techniques. For those acres where glyphosate-resistant broadleaf weeds may already 

be present and where dicamba could be used for control of resistant or hard-to-control 

broadleaf weeds, the cultivation of cotton containing the DGT cotton traits would be an option 

for growers. DGT cotton combined with glyphosate-tolerant cotton would provide the tools 

to manage dicamba-, glufosinate-, and glyphosate-resistant weeds and mitigate evolution and 

development of resistant weed populations (see Section II.B.2.d and Appendix B of this 

Environmental Report for more detail). The use of dicamba and glufosinate, plus residuals, in 

select situations in conjunction with glyphosate provides growers with an effective herbicide 

system with three distinct modes-of-action. 

To support the introduction of varieties containing DGT cotton, Monsanto will use multiple 

methods to distribute technical and stewardship information to growers, academics and grower 

advisors regarding the use of the product as part of a diversified weed management system. 

Growers who purchase Monsanto varieties containing DGT cotton sign a limited use license 

known as the Monsanto Technology Stewardship Agreement (MTSA). The MTSA obligates

growers to comply with certain requirements, including the Monsanto Technology Use Guide 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 190 of 946

(TUG). The TUG will set forth the requirements and best practices for the cultivation of DGT 

cotton including recommendations on weed resistance management practices. 

The weed resistance management practices that are designed to minimize the potential for the 

development of herbicide-resistant weeds will be articulated in the TUG and also be broadly 

communicated to growers and retailers. These practices will be communicated through a 

variety of means, including direct communications to each grower authorized to purchase and 

plant a cotton variety containing DGT cotton, a public website, and reports in farm media 

publications. The overall weed resistance management program will be reinforced through 

collaborations with U.S. academics, who will provide their recommendations for appropriate 

stewardship of dicamba and glufosinate in cotton production, as well as by collaboration with 

crop commodity groups who have launched web-based weed resistance educational modules 

(WSSA 2012). 

Dicamba has been used extensively on millions of acres for over 40 years. To date, there are 

four species with known resistant biotypes to dicamba in the U.S./Canada: common 

hempnettle, kochia, prickly lettuce, and wild mustard (Heap 2012d). Additionally, a population 

of common lambsquarters has been confirmed to be resistant in New Zealand, for a total of 

five species worldwide with confirmed resistant biotypes to dicamba. Glufosinate has been 

used since 1994 and, to date, there are two weed species with confirmed resistance to 

glufosinate: goosegrass in Malaysia and Italian ryegress in Oregon, U.S.(Heap 2012b). See 

Appendix B of this Environmental Report, for additional information on dicamba- and 

glufosinate-resistant biotypes. However, the introduction of DGT cotton is not likely to result 

in a substantial risk for the development of dicamba- or glufosinate-resistant weeds for several 

reasons: 

The use of residuals in select situations, plus glyphosate or glufosinate, in addition to dicamba, 

would provide multiple modes-of-action on key broadleaf weeds which would diminish the 

chance for selection of dicamba- or glufosinate-resistant broadleaf weeds; 

In fields where glyphosate-resistant broadleaf weeds are present or suspected, glyphosate plus 

dicamba and/or glufosinate will be recommended. In addition, it will be recommended that an 

additional herbicide with a 3rd mode-of-action that also has activity on the glyphosate-resistant 

broadleaf weed be used, thereby providing two effective modes-of-action to control glyphosateresistant weeds; and 

The proposed dicamba herbicide label for DGT cotton, existing glyphosate herbicide labels, 

and separate Monsanto weed management recommendations (e.g., Monsanto’s annual TUG 

and publicly available websites) will specify the effective rate and timing of dicamba, glyphosate, 

and glufosinate applications for optimal weed control, reducing the selection pressure for 

dicamba as well as glyphosate and glufosinate. The new use pattern and draft label for dicamba 

to be used on DGT cotton are subject to regulatory approval by EPA.

DGT cotton integrated into the glyphosate-tolerant cotton systems provides a simple, effective 

weed management system to control existing resistant weeds and allows for an easy way to 

incorporate multiple effective herbicide modes-of-action for effective weed resistance 

management. In the unlikely case that broadleaf weeds were to evolve or develop resistance to 

dicamba or glufosinate, existing cultivation and alternative herbicide tools (see Section II.B.2.d 

for a description of alternative herbicides) would remain potential options to provide effective 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 191 of 946

control. Furthermore, under the Deregulation in Whole Alternative, the potential for resistance 

to continue to evolve and develop for other popular herbicides used in cotton production, such 

as ALS and PPO herbicides, is expected to be reduced. However, the development of 

resistance to alternative herbicides can be managed through the use of diversified weed 

resistance management strategies that utilize different mechanisms of control as part of weed 

management practices, such as mechanical tillage or other cultural practices. On the basis of 

the above analysis, the Deregulation in Whole and No Action Alternatives are similar regarding 

potential increased costs and complexity in weed control for cotton growers. However, the No 

Action Alternative would not provide as many management options for addressing the 

development of herbicide-resistant weeds, and would not take advantage of DGT cotton to 

help sustain the long-term agronomic, environmental and economic value and benefits of 

glyphosate-tolerant cotton.

IV.B.6.d. Approval in Whole of DT Soybean and DGT Cotton 

As discussed above, DT soybean and DGT cotton integrated into the glyphosate-tolerant

soybean and cotton systems provides a simple, effective weed management system to control 

existing resistant weeds and allows for an easy way to incorporate multiple effective herbicide 

modes-of-action for effective weed resistance management. In the unlikely case that broadleaf 

weeds were to evolve or develop with resistance to dicamba, existing cultivation and alternative 

herbicide tools (see Appendix A for a description of alternative herbicides) would remain 

potential options to provide effective control. Furthermore, under the Deregulation in Whole 

Alternative, the potential for resistance to continue to evolve and develop for other popular 

herbicides used in soybean and cotton production, such as ALS and PPO herbicides, is 

expected to be reduced. However, the development of resistance to alternative herbicides can 

be managed through the use of diversified weed resistance management strategies that utilize 

different mechanisms of control as part of weed management practices, such as mechanical 

tillage or other cultural practices. On the basis of the above analysis, the Deregulation in Whole 

and No Action Alternatives are similar regarding potential increased costs and complexity in 

weed control for cotton growers. However, the No Action Alternative would not provide as 

many management options for addressing the development of herbicide-resistant weeds, and 

would not take advantage of DT soybean and DGT cotton to help sustain the long-term 

agronomic, environmental and economic value and benefits of glyphosate-tolerant soybean and 

cotton.

IV.B.7. Organic Production

IV.B.7.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would remain subject to the 

regulatory requirements of 7 CFR part 340 and the plant pest provisions of the Plant Protection 

Act. The availability of GE, non-GE and organic soybean and cotton would not change as a 

result of the continued regulation of DT soybean or DGT cotton. Organic seed producers 

would continue to utilize the same methods as applied in certified seed production systems 

designed to maintain soybean and cotton seed identity and meet National Organic Standards as 

established by the NOP. 

As described in Section II.B., organic soybean production is a very small portion of the soybean 

market which would not be expected to change under the No Action Alternative. Also, 
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agronomic practices employed to produce organic soybean would remain unaffected by 

selection of the No Action Alternative. 

Acreage devoted to organic cotton production is small relative to that of total cotton acres, the 

majority of which is planted with GE varieties. Total organic cotton acres have remained 

relatively steady at ~15,000 acres between 2000 and 2008 (USDA-APHIS 2013). As described 

in Section II.B.2.e, organic cotton production is a very small portion of the cotton market 

which would not be expected to change under the No Action Alternative. Also, agronomic 

practices employed to produce organic cotton would remain unaffected by selection of the No 

Action Alternative. 

It is important to note that the current NOP regulations do not specify an acceptable threshold 

level for the adventitious presence of GE materials in an organic-labeled product. The 

unintentional presence of the products of excluded methods does not affect the status of an 

organic product or operation when the operation has not used excluded methods and has taken 

reasonable steps to avoid contact with the products of excluded methods as detailed in their 

approved organic system plan (Ronald and Fouche 2006; USDA-AMS 2010; 2011). However, 

certain markets or contracts may have defined thresholds regarding levels of GE presence 

(Non-GMO Project 2012).

IV.B.7.b. Approval in Whole of DT Soybean, but not DGT Cotton 

As described above, the availability of GE, non-GE and organic cotton seed would not change 

as a result of the continued regulation of DGT cotton. Organic seed producers would continue 

to utilize the same methods as applied in certified seed production systems designed to 

maintain cotton seed identity and meet National Organic Standards as established by the NOP. 

Acreage devoted to organic cotton production is small relative to that of total cotton acres, the 

majority of which is planted with GE varieties. Total organic cotton acres have remained 

relatively steady at ~15,000 acres between 2000 and 2008 (USDA-APHIS 2013). As described 

in Section II.B., organic cotton production is a very small portion of the cotton market which 

would not be expected to change under the No Action Alternative. Also, agronomic practices 

employed to produce organic cotton would remain unaffected by selection of the No Action 

Alternative. It is important to note that the current NOP regulations do not specify an 

acceptable threshold level for the adventitious presence of GE materials in an organic-labeled 

product. The unintentional presence of the products of excluded methods does not affect the 

status of an organic product or operation when the operation has not used excluded methods 

and has taken reasonable steps to avoid contact with the products of excluded methods as 

detailed in their approved organic system plan (Ronald and Fouche 2006; USDA-AMS 2010; 

2011). However, certain markets or contracts may have defined thresholds regarding levels of 

GE presence (Non-GMO Project 2012).

With respect to DT soybean, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba-tolerant event DT soybean 

with the current glyphosate-tolerant soybean systems using traditional breeding techniques. GE 

herbicide-tolerant soybean lines are already extensively used by farmers, while organic soybean 

production represents a small percentage of the total U.S. soybean acreage. Similar to the No 

Action Alternative, organic soybean acreage is likely to remain small, regardless of whether new 

varieties of GE or non-GE soybean varieties, including DT soybean, become available for 

commercial soybean production.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 193 of 946

When compared to other GE varieties of soybean, DT soybean should not present any new or 

different issues and impacts for organic and other specialty soybean producers and consumers. 

Organic producers employ a variety of measures to manage identity and preserve the integrity 

of organic production systems (Guerena and Sullivan 2003). Agronomic tests conducted by 

Monsanto found DT soybean to be substantially equivalent to the non-GE control variety; 

hence, pollination characteristics would be similar to other soybean varieties currently available 

to growers (Appendix G to this environmental report). Given the largely self-pollinating nature 

and the limited pollen movement of soybean, it is not likely that organic farmers will be 

substantially affected by a determination of nonregulated status of DT soybean when organic 

soybean is produced in accordance with agronomic practices designed to meet National 

Organic Standards. This is particularly the case given that 93% of all soybean acres currently 

are already GE. The Deregulation in Whole Alternative is not anticipated to increase the 

overall acreage of GE soybean, but rather is anticipated to be adopted by growers already using 

another GE variety, but who are interested in adopting an alternative mode-of-action herbicide 

to control herbicide-resistant or hard-to-control broadleaf weeds or to mitigate the potential for 

development of herbicide-resistant weeds.

The trend in the cultivation of GE soybean, non-GE, and organic soybean varieties, and the 

corresponding production systems to maintain varietal integrity are likely to remain the same as 

the No Action Alternative. Accordingly, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on organic soybean production.

IV.B.7.c. Approval in Whole of DGT Cotton, but not DT Soybean 

As described above, the availability of GE, non-GE and organic soybean seed would not 

change as a result of the continued regulation of DT soybean. Organic seed producers would 

continue to utilize the same methods as applied in certified seed production systems designed 

to maintain soybean seed identity and meet National Organic Standards as established by the 

NOP. As described in Section II.B.1.e, organic soybean production is a very small portion of 

the soybean market which would not be expected to change under the No Action Alternative. 

Also, agronomic practices employed to produce organic soybean would remain unaffected by 

selection of the No Action Alternative. It is important to note that the current NOP 

regulations do not specify an acceptable threshold level for the adventitious presence of GE 

materials in an organic-labeled product. The unintentional presence of the products of 

excluded methods does not affect the status of an organic product or operation when the 

operation has not used excluded methods and has taken reasonable steps to avoid contact with 

the products of excluded methods as detailed in their approved organic system plan (Ronald 

and Fouche 2006; USDA-AMS 2010; 2011). However, certain markets or contracts may have 

defined thresholds regarding levels of GE presence (Non-GMO Project 2012).

With respect to DGT cotton, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba and glufosinate-tolerant 

event DGT cotton with the current glyphosate-tolerant cotton systems using traditional 

breeding techniques. GE herbicide-tolerant cotton lines are already extensively used by 

farmers, while organic cotton production represents a small percentage (less than 0.2%) of the 

total U.S. cotton acreage (USDA-ERS 2008). Similar to the No Action Alternative, organic 

cotton acreage is likely to remain small, regardless of whether new varieties of GE or non-GE 

cotton varieties, including DGT cotton, become available for commercial cotton production.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 194 of 946

When compared to other GE varieties of cotton, DGT cotton should not present any new or 

different issues and impacts for organic cotton producers and consumers. Organic producers 

employ a variety of measures to manage identity and preserve the integrity of organic 

production systems (Guerena and Sullivan 2003). Agronomic tests conducted by Monsanto 

found DGT cotton substantially equivalent to the non-GE control variety; hence, pollination 

characteristics would be similar to other cotton varieties currently available to growers (see 

Appendix G). Given the largely self-pollinating nature and the limited pollen movement of 

cotton (Niles and Feaster 1984; OECD 2008), it is not likely that organic farmers will be 

substantially affected by a determination of nonregulated status of DGT cotton when organic 

cotton is produced in accordance with agronomic practices designed to meet National Organic 

Standards. This is particularly the case given that 90% of all cotton acres currently are already 

GE. The Deregulation in Whole Alternative is not anticipated to increase the overall acreage of 

GE cotton, but rather is anticipated to be adopted by growers already using another GE variety, 

but who are interested in adopting an alternative mode-of-action herbicide to control herbicideresistant weeds or to mitigate the potential for development of herbicide-resistant weeds.

The trend in the cultivation of GE cotton, non-GE, and organic cotton varieties, and the 

corresponding production systems to maintain varietal integrity are likely to remain the same as 

the No Action Alternative. Accordingly, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on organic cotton production.

IV.B.7.d. Approval in Whole of DT Soybean and DGT Cotton

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of DT soybean and DGT cotton with the current glyphosate-tolerant 

soybean and cotton systems using traditional breeding techniques. GE herbicide-tolerant 

soybean and cotton varieties are already extensively used by farmers, while organic soybean and 

cotton production represents a small percentage of the total U.S. soybean and cotton acreage. 

Similar to the No Action Alternative, combined organic soybean and cotton acreage is likely to 

remain small, regardless of whether new varieties of GE or non-GE soybean varieties, including 

DT soybean and DGT cotton, become available for commercial production.

When compared to other GE varieties of soybean and cotton, DT soybean and DGT cotton 

should not present any new or different issues and impacts for organic and other specialty 

producers and consumers. Organic producers employ a variety of measures to manage identity 

and preserve the integrity of organic production systems (Guerena and Sullivan 2003). 

Agronomic tests conducted by Monsanto found DT soybean and DGT cotton to be

substantially equivalent to the non-GE control variety; hence, pollination characteristics would 

be similar to other soybean varieties currently available to growers (Appendix G to this 

Environmental Report). Given the largely self-pollinating nature and the limited pollen 

movement of soybean and cotton (see Sections II.B.1.c and II.B.2.c), it is not likely that organic 

farmers will be substantially affected by a determination of nonregulated status of DT soybean 

and DGT cotton when organic soybean and cotton is produced in accordance with agronomic 

practices designed to meet National Organic Standards. This is particularly the case given that 

93% of all soybean acres and 90% of all cotton acres currently are already GE. The 

Deregulation in Whole Alternative is not anticipated to increase the overall acreage of GE 

soybean and GE cotton, but rather is anticipated to be adopted by growers already using 

another GE variety, but who are interested in adopting an alternative mode-of-action herbicide 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 195 of 946

to control herbicide-resistant weeds or to mitigate the potential for development of herbicideresistant weeds.

The trend in the cultivation of GE, non-GE, and organic soybean and cotton varieties, and the 

corresponding production systems to maintain varietal integrity are likely to remain the same as 

the No Action Alternative. Accordingly, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on organic soybean and cotton 

production.

IV.B.8. Other Specialty Market Production

IV.B.8.a. No Action Alternative for DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. As discussed in Section II.B., specialty soybean and cotton is cultivated in 

the U.S. Current availability and usage of commercially cultivated (both GE and non-GE) 

soybean and cotton, as well as identity preserved specialty soybean and cotton, are expected to 

remain the same under the No Action Alternative. Under the No Action Alternative, specialty 

soybean and cotton production would be expected to continue much as it is currently, with 

continuing fluctuations in production based on supply and demand and other economic 

considerations.

IV.B.8.b. Approval in Whole of DT Soybean, but not DGT Cotton 

As discussed above, under the No Action Alternative, specialty cotton production would be 

expected to continue much as it is currently, with continuing fluctuations in production based 

on supply and demand and other economic considerations.

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with the current 

glyphosate-tolerant soybean systems using traditional breeding techniques. As discussed in 

Section II.B, GE soybean lines are grown on approximately 93% of U.S. soybean acres. It is 

possible that DT soybean could be incorporated using conventional breeding with a range of

specialty soybean products, including those which have been developed using biotechnology,

such as high oleic soybean. Its use would not be expected to present any new or different 

issues or impacts for specialty soybean producers and consumers.

With the exception of its tolerance to dicamba, DT soybean has been shown to be no different 

from non-GE soybean in its agronomic and reproductive characteristics, including pollen 

diameter, viability and morphology (see Appendix G for details). Thus, DT soybean is 

expected to be no different from other soybean in its ability to cross-pollinate with other 

soybean; therefore, no additional means beyond those already used to produce GE-derived and 

specialty soybean will be needed if DT soybean were grown commercially. 

A determination of nonregulated status of DT soybean would not change the availability and 

quality of seed for specialty soybean varieties. Conventional management practices and 

procedures, as described previously for soybean seed production and seed handling are in place 

to maintain the quality of various types of soybean. Soybean growers have utilized these 

methods effectively to meet the standards for the production of specialty crop seed. Therefore, 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 196 of 946

the Deregulation in Whole and No Action Alternatives are the same regarding their potential 

impact on specialty soybean growers.

IV.B.8.c. Approval in Whole of DGT Cotton, but not DT Soybean 

As discussed above, under the No Action Alternative, specialty soybean production would be 

expected to continue much as it is currently, with continuing fluctuations in production based 

on supply and demand and other economic considerations.

With respect to DGT cotton, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba and glufosinate-tolerant 

event DGT cotton with the current glyphosate-tolerant cotton systems using traditional 

breeding techniques. As discussed in Section II.B., GE cotton lines are grown on 

approximately 90% of U.S. cotton acres. Like other GE traits to date, DGT cotton is not 

planned for incorporation into specialty cotton. Its use would not be expected to present any 

new or different issues or impacts for specialty cotton producers and consumers.

With the exception of its tolerances to both dicamba and glufosinate, DGT cotton has been 

shown to be no different from non-GE cotton in its agronomic and reproductive 

characteristics, including pollen diameter, viability and morphology (see Appendix G for

details). Thus, DGT cotton is expected to be no different from other cotton in its ability to 

cross-pollinate with other cotton; therefore, no additional means beyond those already used to 

produce GE-derived and specialty cotton will be needed if DGT cotton were grown 

commercially. 

A determination of nonregulated status of DGT cotton would not change the availability and 

quality of seed for specialty cotton varieties. Conventional management practices and 

procedures, as described previously for cotton seed production and seed handling are in place 

to maintain the quality of various types of cottonseed. Cotton growers have utilized these 

methods effectively to meet the standards for the production of specialty crop seed. Therefore, 

the Deregulation in Whole and No Action Alternatives are the same regarding their potential 

impact on specialty cotton growers.

IV.B.8.d. Approval in Whole of DT Soybean and DGT Cotton 

As discussed above, the difference between the No Action and the Deregulation in Whole 

Alternatives would be the gradual integration of DT soybean and DGT cotton with the current 

glyphosate-tolerant cotton systems using traditional breeding techniques. As discussed in 

Section II.B.2.b, GE lines are grown on approximately 93% of U.S. soybean and 90% of U.S. 

cotton acres. DT soybean could be incorporated using conventional breeding with a range of 

specialty soybean products, including those which have been developed using biotechnology 

such as high oleic soybean. DGT cotton is not planned for incorporation into specialty cotton. 

Their use would not be expected to present any new or different issues or impacts for specialty 

producers and consumers.

With the exception of their tolerances to dicamba (and glufosinate in the case of cotton), DT 

soybean and DGT cotton have been shown to be no different from non-GE cotton in its 

agronomic and reproductive characteristics, including pollen diameter, viability and morphology 

(see Appendix G for details). Thus, DT soybean and DGT cotton are expected to be no 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 197 of 946

different from other soybean and cotton in their ability to cross-pollinate with other soybean 

and cotton; therefore, no additional means beyond those already used to produce GE-derived 

and specialty soybean and cotton will be needed if DT soybean and DGT cotton were grown 

commercially. 

A determination of nonregulated status of DT soybean and DGT cotton would not change the 

availability and quality of seed for specialty soybean and cotton varieties. Conventional 

management practices and procedures, as described previously for soybean and cotton seed 

production and seed handling are in place to maintain the quality of various types of soybean 

and cottonseed. Soybean and cotton growers have utilized these methods effectively to meet 

the standards for the production of specialty crop seed. Therefore, the Deregulation in Whole 

and No Action Alternatives are the same regarding their potential impact on specialty soybean 

and cotton growers.

IV.B.9. Seed Production

IV.B.9.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially cultivated (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. DT soybean and DGT cotton would not be propagated to any extent by seed 

producers because there would be no commercial demand for seed containing DT soybean and 

DGT cotton. Under the No Action Alternative, current soybeans and cotton seed production 

practices are not expected to change.

IV.B.9.b. Approval in Whole of DT Soybean, but not DGT Cotton 

As described above, under the No Action Alternative, current cotton seed production practices 

are not expected to change because DGT cotton would not be propagated to any extent by 

seed producers as there would be no commercial demand for seed containing DGT cotton.

With respect to DT soybean, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba-tolerant event DT soybean 

with the current glyphosate-tolerant soybean systems using traditional breeding techniques. 

Certified seed production is a carefully managed process (see Section II.B. for additional detail). 

DT soybean is not expected to impact certified seed production practices or production of 

specialty soybean seed for reasons described in this section.

If DT soybean is deregulated, seed production would occur within production systems 

previously developed by seed producers for certified soybean seed, using standards specified by 

AOSCA to assure compliance with the Federal Seed Act. DT soybean has been thoroughly 

characterized and (with the exception of its tolerances to dicamba) is not agronomically or 

phenotypically different from commercial soybean (as detailed in Appendix G). The difference 

between the Deregulation in Whole and the No Action Alternative is expected to be integration 

of DT soybean into glyphosate-tolerant soybean varieties using traditional breeding techniques. 

For those seed production acres where glyphosate-resistant weeds may already be present or 

where application of a herbicide with a different mode-of-action would aid in weed control or 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 198 of 946

the implementation of weed resistant management practices, the cultivation of soybean 

containing the DT soybean traits would be an option for seed producers. 

Certified soybean seed producers can and have effectively implemented practices (e.g., isolation 

distances during the growing season, equipment cleaning during harvest, and post-harvest 

separation of harvested seed) that allow them to maintain commercially acceptable levels of 

varietal purity. Achieving these purity standards is facilitated by the fact that soybean is a highly 

self-pollinated species that exhibits very low levels of outcrossing. Because DT soybean has 

been shown to be no different from commercial soybean relative to pollen morphology and 

viability, the cultivation of DT soybean will not impact the ability to implement production 

practices required for the production of certified seed. Therefore, the Deregulation in Whole 

and No Action Alternatives are the same regarding their potential impact on certified seed 

production practices.

IV.B.9.c. Approval in Whole of DGT Cotton, but not DT Soybean 

As described above, under the No Action Alternative, current soybean seed production 

practices are not expected to change because DT soybean would not be propagated to any 

extent by seed producers as there would be no commercial demand for seed containing DT 

soybean.

With respect to DGT cotton, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba and glufosinate-tolerant 

event DGT cotton with the current glyphosate-tolerant cotton systems using traditional 

breeding techniques. Certified seed production is a carefully managed process (see Section II.B 

for additional detail). DGT cotton is not expected to impact certified seed production practices 

or production of specialty cottonseed for reasons described in this section.

If DGT cotton is deregulated, seed production would occur within production systems 

previously developed by seed producers for certified cotton seed, using standards specified by 

AOSCA to assure compliance with the Federal Seed Act. DGT cotton has been thoroughly 

characterized and (with the exception of its tolerances to both dicamba and glufosinate) is not 

agronomically or phenotypically different from commercial cotton (as detailed in Appendix G). 

The difference between the Deregulation in Whole and the No Action Alternative is expected 

to be integration of DGT cotton into glyphosate-tolerant cotton varieties using traditional 

breeding techniques. For those seed production acres where glyphosate-resistant weeds may 

already be present or where application of a herbicide with a different mode-of-action would 

aid in weed control or the implementation of weed resistant management practices, the 

cultivation of cotton containing the DGT cotton traits would be an option for seed producers. 

Certified cotton seed producers can and have effectively implemented practices (e.g., isolation 

distances during the growing season, equipment cleaning during harvest, and post-harvest 

separation of harvested seed) that allow them to maintain commercially acceptable levels of 

varietal purity. Achieving these purity standards is facilitated by the fact that cotton is a selfpollinated species that exhibits low levels of outcrossing. Because DGT cotton has been shown 

to be no different from commercial cotton relative to pollen morphology and viability, the 

cultivation of DGT cotton will not impact the ability to implement production practices 

required for the production of certified seed. Therefore, the Deregulation in Whole and No 
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Action Alternatives are the same regarding their potential impact on certified seed production 

practices.

IV.B.9.d. Approval in Whole of DT Soybean and DGT Cotton 

As discussed above, the difference between the No Action and the Deregulation in Whole 

Alternatives would be the gradual integration of DT soybean and DGT cotton with the current 

glyphosate-tolerant cotton systems using traditional breeding techniques. Certified seed 

production is a carefully managed process (see Section II.B for additional detail). DT soybean 

and DGT cotton are not expected to impact certified seed production practices of soybean or 

cottonseed for reasons described in this section.

If DT soybean and DGT cotton are deregulated, seed production would occur within 

production systems previously developed by seed producers for certified cotton seed, using 

standards specified by AOSCA to assure compliance with the Federal Seed Act. DT soybean 

and DGT cotton have been thoroughly characterized and with the exception of their herbicide 

tolerances are not agronomically or phenotypically different from commercial soybean and 

cotton (as detailed in Appendix G). The difference between the Deregulation in Whole and the 

No Action Alternative is expected to be integration of DT soybean and DGT cotton into 

glyphosate-tolerant varieties using traditional breeding techniques. For those seed production 

acres where glyphosate-resistant weeds may already be present or where application of a 

herbicide with a different mode-of-action would aid in weed control or the implementation of 

weed resistant management practices, the cultivation of soybean and cotton containing the DT 

soybean and DGT cotton traits would be an option for seed producers. 

Certified soybean and cotton seed producers can and have effectively implemented practices 

(e.g., isolation distances during the growing season, equipment cleaning during harvest, and 

post-harvest separation of harvested seed) that allow them to maintain commercially acceptable 

levels of varietal purity. Achieving these purity standards is facilitated by the fact that soybean 

and cotton are self-pollinated species that exhibits low levels of outcrossing. Because DT 

soybean and DGT cotton have been shown to be no different from commercial cotton relative 

to pollen morphology and viability, the cultivation of DT soybean and DGT cotton will not 

impact the ability to implement production practices required for the production of certified 

seed. Therefore, the Deregulation in Whole and No Action Alternatives are the same regarding 

their potential impact on certified seed production practices.

IV.C. PHYSICAL ENVIRONMENT

The following section discusses the potential impacts of the No Action Alternative and 

Deregulation in Whole of either DT soybean, DGT cotton or both on the physical 

environment, including impacts on land use, soil quality, water quality, air quality and climate 

change. In addition to discussing the potential impacts of the plants themselves, this section 

also discusses potential impacts associated with the use of dicamba. As discussed elsewhere in 

this report, however, Congress transferred regulatory authority over herbicides from USDA to 

EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or herbicide resistance, 

and no authority to consider herbicide impacts under the PPA. Nonetheless, because APHIS 

indicated in its Notice of Intent to Prepare an Environmental Impact Statement (78 Fed. Reg. 

28796, May 16, 2013) that it would be considering herbicide effects and herbicide resistance as 

part of the NEPA process, Monsanto has included a discussion of herbicide impacts in the 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 200 of 946

following section. Importantly, however, Monsanto believes that APHIS has no legal 

obligation under NEPA to consider herbicide impacts or herbicide resistance in any 

Environmental Impact Statement or Environmental Assessment. See DOT v. Public Citizen, 

541 U.S. 752, 770, 769 (2004) (where an agency has no ability to prevent a certain effect due to 

its limited statutory authority over the relevant actions, the agency cannot be considered a 

legally relevant “cause” of the effect, and is therefore not required to analyze the environmental 

impact of an action it could not refuse to perform). See also Center for Food Safety v. Vilsack, 

No. 12-15052, 2013 U.S. App. LEXIS 9920, at *16-17 (9th Cir. 2013) (“If APHIS concludes 

that the presumptive plant pest does not exhibit any risk of plant pest harm, APHIS must 

deregulate it since the agency does not have jurisdiction to regulate organisms that are not plant 

pests.”).

IV.C.1. Land Use Impacts

IV.C.1.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated articles and would not be widely grown. Under this alternative, dicamba and 

glufosinate use would likely remain similar to today’s use pattern. Land use changes would not 

be expected with the No Action Alternative. Relatively minor fluctuations in soybean and 

cotton acreage would be expected, resulting from environmental, agronomic, economic and 

governmental influences. 

IV.C.1.b. Approval in Whole of DT Soybean, But Not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes to land use. Growers likely would continue to use glyphosate and 

glufosinate-tolerant cotton in the same areas and with the same weed control options as 

currently used.

With respect to DT soybean, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba-tolerant event DT soybean 

with the current glyphosate-tolerant soybean systems using traditional breeding techniques. For 

those acres where glyphosate-resistant weeds may already be present, where application of an 

herbicide with a different mode-of-action would aid in weed control, or for grower 

implementation of weed resistant management practices, the cultivation of soybeans containing 

the DT soybean trait would be an option for growers. 

Herbicide-tolerant soybean has been deregulated and grown in the U.S. since 1996. 

Glyphosate-tolerant soybean currently occupies greater than 90% of total soybean acres. 

Fluctuations in total soybean acreage before and after herbicide-tolerant soybean was 

commercialized(USDA-NASS 2011d) indicates that factors unrelated to the availability of the 

herbicide-tolerant trait play a role in total soybean acres planted. Agricultural land use, and 

consequently crop production, is dictated by many factors, the most significant of which is 

commodity prices. Accordingly, growers may increase acres dedicated to soybean production 

to meet increased demand, but they do so in response to commodity prices and market 

demand, not in response to availability or adoption of biotechnology-derived traits.
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With the exception of tolerance to dicamba, DT soybean is phenotypically and agronomically 

unchanged from conventional soybean. Phenotypic and agronomic information collected from 

field trials conducted in 2008 using the same agricultural inputs showed no meaningful changes 

between DT soybean and the conventional control (see Appendix G of this Environmental 

Report). Compared to conventional soybean, DT soybean does not display increased 

susceptibility to pests or diseases, and is not changed regarding crop emergence, growth 

development or yield. Additional laboratory and greenhouse-based experiments reached the 

same conclusion; DT soybean was unchanged compared to the conventional control for seed 

germination and symbiotic relationship parameters. Therefore, production management 

practices (e.g., planting and harvest timing, fertilizer inputs, and pesticide use other than 

dicamba) are not expected to change with the introduction of DT soybean. Similarly, because 

there are no changes in growth and development or yield, there is no expectation that the 

introduction of DT soybean will significantly alter the geographical range of commercial 

soybean cultivation. Thus, the introduction of DT soybean is not anticipated to facilitate 

production of soybean in areas where it is not currently grown or have significant impact on 

total soybean production acres. Therefore, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on land use.

IV.C.1.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to land use. 

With respect to DGT cotton, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba-tolerant event DGT cotton

with the current glyphosate-tolerant cotton systems using traditional breeding techniques. For 

those acres where glyphosate-resistant weeds may already be present, where application of an 

herbicide with a different mode-of-action would aid in weed control, or for grower 

implementation of weed resistant management practices, the cultivation of cotton containing 

the DGT cotton trait would be an option for growers. 

Currently, herbicides are used on nearly all (>99%) U.S. cotton acres and GE cotton lines are 

grown on approximately 90% of U.S. cotton acres. Agricultural land use, and consequently 

crop production, is dictated by many factors, the most significant of which is commodity prices. 

Accordingly, growers may increase acres dedicated to cotton production to meet increased 

demand, but they do so in response to commodity prices and market demand, not in response 

to availability or adoption of biotechnology-derived traits.

With the exception of tolerance to dicamba and glufosinate, DGT cotton is phenotypically and 

agronomically unchanged from conventional cotton. Phenotypic and agronomic information 

collected from field trials conducted in 2010 using the same agricultural inputs showed no 

meaningful changes between DGT cotton and the conventional control (see Appendix G of 

this Environmental Report). Compared to conventional cotton, DGT cotton does not display 

increased susceptibility to pests or diseases, and is not changed regarding crop emergence, 

growth development or yield. Additional laboratory and greenhouse-based experiments 

reached the same conclusion; DGT cotton was unchanged compared to the conventional 

control for seed germination and symbiotic relationship parameters. Therefore, production 

management practices (e.g., planting and harvest timing, fertilizer inputs, and pesticide use other 

than dicamba and glufosinate) are not expected to change with the introduction of DGT 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 202 of 946

cotton. Similarly, because there are no changes in growth and development or yield, there is no 

expectation that the introduction of DGT cotton and its use in development of cotton varieties 

will significantly alter the geographical range of commercial soybean cultivation. Thus, the 

introduction of DGT cotton is not anticipated to facilitate production of cotton in areas where 

it is not currently grown or have significant impact on total cotton production acres. 

Therefore, the Deregulation in Whole and No Action Alternatives are the same regarding their 

potential impact on land use.

IV.C.1.d. Approval in Whole of DT Soybean and DGT Cotton

Deregulation in Whole of DT soybean and DGT cotton is expected to result in the gradual 

integration of the dicamba tolerance with the current glyphosate-tolerant soybean and cotton

systems using traditional breeding techniques. For those acres where glyphosate-resistant

weeds may already be present, where application of an herbicide with a different 

mode-of-action would aid in weed control, or for grower implementation of weed resistant 

management practices, the cultivation of soybean or cotton containing the DT soybean or 

DGT cotton traits would be an option for growers. 

Agricultural land use, and consequently crop production, is dictated by many factors, the most 

significant of which is commodity prices. Accordingly, growers may increase acres dedicated to 

soybean or cotton production to meet increased demand, but they do so in response to 

commodity prices and market demand, not in response to availability or adoption of 

biotechnology-derived traits.

With the exception of tolerance to dicamba (and glufosinate in the case of DGT cotton), DT 

soybean and DGT cotton are phenotypically and agronomically unchanged from conventional 

soybeans and cotton. Phenotypic and agronomic information collected from field trials 

conducted in 2008 and 2010, respectively for DT soybean and DGT cotton, using the same 

agricultural inputs showed no meaningful changes between DT soybean and DGT cotton and 

the conventional control. Compared to conventional soybeans and cotton, DT soybean and 

DGT cotton does not display increased susceptibility to pests or diseases, and is not changed 

regarding crop emergence, growth development or yield. Additional laboratory and 

greenhouse-based experiments reached the same conclusion; DT soybean and DGT cotton 

were unchanged compared to the conventional control for seed germination and symbiotic 

relationship parameters. Therefore, production management practices (e.g., planting and 

harvest timing, fertilizer inputs, and pesticide use other than dicamba and glufosinate) are not 

expected to change with the introduction of DT soybean and DGT cotton. Similarly, because 

there are no changes in growth and development or yield, there is no expectation that the 

introduction of DT soybean and DGT cotton and their use in development of soybean and 

cotton varieties will significantly alter the geographical range of commercial soybean and cotton 

cultivation. Thus, the introduction of DT soybean and DGT cotton is not anticipated to 

facilitate production of soybean and cotton in areas where it is not currently grown or have 

significant impact on total soybean and cotton production acres. Therefore, the Deregulation 

in Whole and No Action Alternatives are the same regarding their potential impact on land use.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 203 of 946

IV.C.2. Soil Quality Impacts

IV.C.2.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, both DT soybean and DGT Cotton would continue to be 

regulated by APHIS. Agronomic practices currently utilized in the cultivation of soybeans and 

cotton would not be altered. However, some combination of herbicides already used in 

soybean and cotton production acres likely would continue to increase in order to control 

problematic weeds. Under the no-action alternative, some growers in certain areas of the U.S.

may reincorporate the use of conventional tillage practices to manage problematic weed 

populations (NRC 2010). An increase in tillage would negate many of the benefits of 

conservation tillage to soil, including improvement of soil structure, reduction of soil 

compaction, conservation of soil moisture, reduction of soil erosion and improvement of soil 

organic matter content. DT soybean and DGT cotton have the potential to mitigate the

evolution and development of glyphosate-resistant weeds because they provide growers with an 

herbicide system with multiple modes-of-action. Thus, it is foreseeable that under the No 

Action Alternative, the inability to integrate DT soybean and DGT cotton into the 

glyphosate-tolerant soybean and cotton systems could, in certain areas of the U.S., increase the 

potential for glyphosate-resistant weed populations to evolve and spread. Under the No Action 

Alternative, adding other herbicides with different modes-of-action into the glyphosate-tolerant 

systems to mitigate development of glyphosate-resistant weeds and control glyphosate-resistant 

weeds would continue to remain an option. Additionally, conventional tillage may increase in 

some instances as an additional means to control problematic weeds. 

IV.C.2.b. Approval in Whole of DT Soybean, But Not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is expected to result in minimal 

changes to soil quality. 

The difference between the Deregulation in Whole of DT soybean and the No Action 

Alternative is expected to be integration of DT soybean into the glyphosate-tolerant soybean 

system using traditional breeding techniques. For those acres where glyphosate-resistant weeds 

may already be present, where application of an herbicide with a different mode-of-action 

would aid in weed control, or for grower implementation of weed resistant management 

practices, the cultivation of soybean containing the DT soybean trait would be an option for 

growers. Approval of DT soybean is likely to encourage use of conservation tillage.

Other than changes associated with herbicide use, DT soybean will not alter the agronomic 

practices typically utilized in the cultivation of soybean. DT soybean has been found to be 

compositionally, agronomically and phenotypically equivalent to conventional soybean. 

Therefore, microbial populations and associated biochemical processes in soil are not expected 

to change with the introduction of DT soybean. The DT soybean-produced protein DMO

(MON 87708 DMO) demonstrates a high level of substrate specificity and is not expected to 

persist in the environment. Studies have shown no impact to the symbiont interactions of DT 

soybean, or to NTOs such as beneficial and pest arthropods when exposed to MON87707

DMO in the field (see DT Soybean Petition and Appendix G of this Environmental Report). 

Based on these data, the cultivation of DT soybean is not expected to impact microbial 

populations and associated biochemical processes. 
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Multiple herbicides are already used in soybean production. Agricultural fields are purposefully 

managed to be weed-free resulting in greater economic benefit to the grower. A discussion of 

weed management practices is provided in Section II.B.1.d. In the U.S., 98% of soybean 

acreage was treated with an herbicide in 2006 (USDA-NASS 2007). Therefore, introduction of 

DT soybean and treatment with dicamba is unlikely to affect soil quality in commercial soybean 

production systems differently than those herbicides already used in soybean. Dicamba has 

been registered by the EPA for use on a wide range of agricultural uses since 1967 (see

Appendices G and H of this Environmental Report). The EPA evaluated dicamba and its 

metabolites as part of the RED (U.S. EPA 2009d), and concluded that dicamba may accumulate 

with frequent and intensive use (2.0 and 2.8 lb per acre a.e. single application and 7.7 lb per acre 

a.e. annually). The EPA mandated reductions in dicamba use rates as part of dicamba’s 

continued registration to effect these and other potential impacts (U.S. EPA 2009d). The 

proposed label submitted by Monsanto, which is currently pending before EPA for application 

of dicamba on DT soybean follows the reduced application rates set by EPA in 2009. Based on 

the proposed application rates (1.0 lb per acre a.e. with a maximum annual rate of 2.0 lb a.e. per 

acre), dicamba is unlikely accumulate or persist in the environment. In addition, results of 

standardized tests with, dicamba and dicamba formulations indicate no long-term effects on 

functional processes of soil microorganisms (carbon respiration and nitrogen transformation) at 

rates proposed for dicamba on DT soybean (EC 2008). 

A reasonably foreseeable impact under full deregulation is mitigation of the evolution and 

development of glyphosate-resistant broadleaf weeds as well as weeds resistant to other 

soybean herbicide classes, such as PPO herbicides, in soybean producing areas. This is because 

growers will likely use dicamba together with glyphosate on the combined dicamba- and 

glyphosate-tolerant soybean product because of the excellent crop tolerance and compatibility 

of the two herbicides. In addition, other herbicides will be recommended and used by growers 

especially in areas in the U.S. where the grower is managing a weed population already resistant 

to glyphosate. This will further assist in mitigating the potential for resistance to dicamba and 

other herbicides used in the DT soybean system. 

Dicamba is an excellent option to mitigate the potential for resistance to other herbicides 

because of its broad spectrum activity on broadleaf weeds and low level of weed resistance, 

specifically on the summer spectrum of weeds known to infest soybean acres. A prominent 

strategy to mitigate the evolution and development of herbicide-resistant weeds is to increase 

the diversity of weed management practices used in a particular cropping system. Diversified 

weed management practices use a combination of cultural (e.g., crop rotation), mechanical (e.g., 

cultivation), and herbicide control practices, including use of herbicides with different modesof-action (Duke and Powles 2009). Thus, DT soybean integrated into the glyphosate-tolerant

soybean system provides the opportunity to increase the diversity of in-crop herbicide control 

options for growers and, in turn, supports the long term sustainability of the glyphosatetolerant soybean system with its established benefits.

Based on this analysis, conservation tillage acres are likely to remain the same, or potentially 

increase, with the introduction of DT soybean. Conservation tillage improves soil structure, 

reduces soil compaction, conserves soil moisture, reduces soil erosion and improves soil 

organic matter content. An increase in tillage is likely in cotton acreage, with corresponding 

adverse impacts on soil quality. Therefore, the approval in whole of DT soybean and No 

Action Alternatives are not significantly different regarding their impact on soil quality.
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IV.C.2.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to soil quality. 

The difference between the No Action and Deregulation in Whole Alternatives for DGT 

cotton would be the gradual integration of the dicamba and glufosinate-tolerant event DGT 

cotton with the current glyphosate-tolerant cotton systems using traditional breeding 

techniques. For those acres where glyphosate-resistant weeds may already be present, where 

application of a herbicide with a different mode-of-action would aid in weed control, or for 

grower implementation of weed resistant management practices, the cultivation of cotton 

containing the DGT cotton trait would be an option for growers. 

DGT cotton will allow the additional use of dicamba and glufosinate herbicides in a diversified

weed management program to control a broad spectrum of grasses and broadleaf weed species 

including glyphosate-resistant biotypes. The availability of DGT cotton could help preserve the 

current acreage of cotton grown using conservation tillage and potentially lead to increased 

conservation tillage adoption. As discussed in Section II.B.2.c of this Environmental Report, 

increases in total acres dedicated to conservation tillage have been attributed to an increased use 

of herbicide-tolerant cotton, which reduces the need for mechanical weed control (McClelland 

et al. 2000; Towery and Werblow 2010). 

A reasonably foreseeable impact under full deregulation is the mitigation of the evolution and 

development of glyphosate-resistant broadleaf weeds as well as weeds resistant to other 

soybean herbicide classes, such as PPO herbicides, in soybean producing areas. This is because 

growers will likely use dicamba together with glyphosate on the combined dicamba- and 

glyphosate-tolerant cotton product because of the excellent crop tolerance and compatibility of 

the two herbicides. In addition, other herbicides will be recommended and used by growers 

especially in cetain areas in the U.S. where the grower is managing a weed population already 

resistant to glyphosate. This will further assist in mitigating the potential for resistance to 

dicamba and other herbicides used in the DGT cotton system. 

Dicamba is an excellent option to mitigate the potential for resistance to other herbicides 

because of its broad spectrum activity on broadleaf weeds and low level of weed resistance, 

specifically on the summer spectrum of weeds known to infest soybean acres. A prominent 

strategy to mitigate the evolution and development of herbicide-resistant weeds is to increase 

the diversity of weed management practices used in a particular cropping system. Diversified 

weed management practices use a combination of cultural (e.g., crop rotation), mechanical (e.g., 

cultivation), and herbicide control practices, including use of herbicides with different modesof-action (Duke and Powles 2009). Thus, DGT cotton integrated into the glyphosate-tolerant 

cotton system provides the opportunity to increase the diversity of in-crop herbicide control 

options for growers and, in turn, supports the long term sustainability of the glyphosatetolerant cotton system with its established benefits.

DGT cotton has been found to be compositionally, agronomically, and phenotypically 

equivalent to commercially cultivated cotton (see Appendix G of this Environmental Report). 

Therefore the physiochemical characteristics of the soil are not expected to change with the 

introduction of DGT cotton. Field studies have shown that DGT cotton is no different than 

commercial cotton in terms of response to abiotic stress (such as compaction, drought, high 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 206 of 946

winds, nutritional deficiency, etc.), disease damage, arthropod-related damage, and pest- and 

beneficial-arthropod abundance (see Appendix G of this Environmental Report). The donor 

organisms for the MON 88701 DMO and PAT (bar) protein coding sequences, Stenotrophomonas 

maltophilia and Streptomyces hygroscopicus, respectively, are bacteria that are ubiquitous in the 

environment, including in soil. Based on these data, the cultivation of DGT cotton is not 

expected to impact physiochemical characteristics of the soil. Impacts associated with DGT 

cotton are expected to be essentially the same as those associated with the No Action 

Alternative. 

Multiple herbicides are already used in nearly all cotton production fields. Agricultural fields are 

purposefully managed for weed control, to provide economic benefit to the grower resulting 

from increased yields (see Section II.B.2.d) Herbicides are used on nearly all (>99%) the cotton 

acres in the U.S., and 30 herbicides, including dicamba and glufosinate, are registered for use on 

cotton (Table A-23). 

Dicamba has been registered by the EPA for a wide range of agricultural uses since 1967 (see 

Appendix A). The EPA evaluated dicamba and its metabolites as part of the RED (U.S. EPA 

2005a; b), and concluded that dicamba may accumulate in soil at the application rates registered 

for use at that time (2.0 and 2.8 lbs per acre a.e. single application and up to 7.7 lbs per acre a.e. 

annually). To prevent dicamba accumulation in soils and to minimize other potential impacts, 

the EPA mandated reductions in dicamba use rates (1.0 lb per acre a.e. with a maximum annual 

rate of 2.0 lbs a.e. per acre) as part of dicamba’s continued registration (U.S. EPA 2009d). The 

proposed label submitted by Monsanto, which is currently pending before EPA for application 

of dicamba on DGT cotton, follows the reduced application rates set by EPA in 2009. In 

addition, results of standardized tests with dicamba and dicamba formulations indicate no longterm effects on functional processes of soil microorganisms (carbon respiration and nitrogen 

transformation) at rates proposed for dicamba on DGT cotton (EFSA 2007c). 

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. No changes in potential impacts of glufosinate on soil 

quality are anticipated. 

Based on this analysis, conservation tillage acres are likely to remain the same, or potentially 

increase, with the introduction of DGT cotton. Conservation tillage improves soil structure, 

reduces soil compaction, conserves soil moisture, reduces soil erosion and improves soil 

organic matter content. An increase in tillage is likely in soybean acreage, with corresponding 

adverse impacts on soil quality. Based on this analysis, the approval in whole and No Action 

Alternatives are not significantly different regarding their impact on soil quality.

IV.C.2.d. Approval in Whole of both DT soybean and DGT cotton

Deregulation in Whole of both DT soybean and DGT cotton is expected result in the 

integration of DT soybean and DGT cotton into the glyphosate-tolerant soybean and cotton 

systems using traditional breeding techniques. For those acres where glyphosate-resistant

weeds may already be present, where application of an herbicide with a different 

mode-of-action would aid in weed control, or for grower implementation of weed resistant 

management practices, the cultivation of soybeans or cotton containing the DT soybean or 

DGT cotton traits would be an option for growers. 
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Other than changes associated with herbicide use, DT soybean and DGT cotton will not alter 

the agronomic practices typically utilized in the cultivation of soybeans and cotton. DT 

soybean and DGT cotton have been found to be compositionally, agronomically and 

phenotypically equivalent to conventional soybean and cotton. Therefore, microbial 

populations and associated biochemical processes in soil are not expected to change with the 

introduction of DT soybean and DGT cotton. Approval of DT soybean and DGT cotton is 

likely to encourage use of conservation tillage. 

Multiple herbicides are already used in soybean and cotton production. Agricultural fields are 

purposefully managed to be weed-free resulting in greater economic benefit to the grower. 

Introduction of DT soybean and DGT cotton and treatment with dicamba and glufosinate is 

unlikely to affect soil quality in commercial soybean and cotton production systems differently 

than those herbicides already used in soybean and cotton. Dicamba has been registered by the 

EPA for use on a wide range of agricultural uses since 1967. The EPA evaluated dicamba and 

its metabolites as part of the RED (U.S. EPA 2009d), and concluded that dicamba may 

accumulate with frequent and intensive use (2.0 and 2.8 lb per acre a.e. single application and 

7.7 lb per acre a.e. annually). The EPA mandated reductions in dicamba use rates as part of 

dicamba’s continued registration to effect these and other potential impacts (U.S. EPA 2009d). 

The proposed labels submitted by Monsanto, which are currently pending before EPA for 

application of dicamba on DT soybean and DGT cotton, follow the reduced application rates 

set by EPA in 2009. Based on the proposed application rates (1.0 lb per acre a.e. with a 

maximum annual rate of 2.0 lb a.e. per acre), dicamba is unlikely accumulate or persist in the 

environment. In addition, results of standardized tests with dicamba and dicamba formulations 

indicate no long-term effects on functional processes of soil microorganisms (carbon 

respiration and nitrogen transformation) at rates proposed for dicamba on DT soybean and 

DGT cotton (EC 2008; EFSA 2007c). 

A reasonably foreseeable impact under full deregulation is mitigation of the evolution and 

development of glyphosate-resistant broadleaf weeds as well as weeds resistant to other 

soybean and cotton herbicide classes, such as PPO herbicides, in certain soybean and cotton 

producing areas of the U.S. This is because growers will likely use dicamba together with 

glyphosate on the combined dicamba- and glyphosate-tolerant soybean and cotton products 

because of the crop tolerance and compatibility of the two herbicides. In addition, other 

herbicides will be recommended and used by growers especially in cases where the grower is 

managing a weed population already resistant to glyphosate. This will further assist in 

mitigating the potential for resistance to dicamba and other herbicides used in the DT soybean 

and DGT cotton systems. 

Dicamba is an excellent option to mitigate the potential for resistance to other herbicides 

because of its broad spectrum activity on broadleaf weeds and low level of weed resistance, 

specifically on the summer spectrum of weeds known to infest soybean acres. A prominent 

strategy to mitigate the evolution and development of herbicide-resistant weeds is to increase 

the diversity of weed management practices used in a particular cropping system. Diversified 

weed management practices use a combination of cultural (e.g., crop rotation), mechanical (e.g., 

cultivation), and herbicide control practices, including use of herbicides with different modesof-action (Duke and Powles 2009). Thus, DT soybean and DGT cotton integrated into the 

glyphosate-tolerant soybean and cotton systems provide the opportunity to increase the 

diversity of in-crop herbicide control options for growers and, in turn, support the long term 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 208 of 946

sustainability of the glyphosate-tolerant soybean and cotton systems with their established 

benefits.

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. No changes in potential impacts of glufosinate on soil 

quality are anticipated. 

Based on this analysis, conservation tillage acres are likely to remain the same, or potentially 

increase, on soybean and cotton acreage with the introduction of DT soybean and DGT 

cotton, as compared to the No Action Alternative. The potential increase in conservation 

tillage acres is the most likely under this scenario. Conservation tillage improves soil structure, 

reduces soil compaction, conserves soil moisture, reduces soil erosion and improves soil 

organic matter content. Based on this analysis, the approval in whole and No Action 

Alternatives for DT soybean and DGT cotton are not significantly different regarding their 

impact on soil quality.

IV.C.3. Water Quality Impacts

IV.C.3.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, both DT soybean and DGT Cotton would continue to be 

regulated by APHIS. Land acreage and agronomic practices (including irrigation) associated 

with soybean and cotton production would not be substantially impacted. Therefore, water 

resources and irrigation practices associated with soybean and cotton production are not likely 

to be substantially affected. 

Surface water has the potential to be impacted from soybean and cotton production by runoff 

from soybean and cotton fields that may carry soil particles and herbicides or other pesticides 

to streams, rivers, lakes, wetlands and other water bodies. As discussed, based on existing data, 

the soil component of runoff is a much more important contributor to surface water impacts 

than is the pesticide component. Similarly, ground water has the potential to be impacted from 

soybean and cotton production due to the use of herbicides or other pesticides for weed 

management.

Growers will continue to choose certain pesticides based on weed, insect and disease pressures, 

cost of seed and other inputs, technology fees, human safety, potential for crop injury, and ease 

and flexibility of the production system (Farnham, 2001; Heiniger, 2000; University of 

Arkansas, 2008). Agricultural production of existing nonregulated herbicide-tolerant GE and 

non-GE soybean and cotton would continue to utilize EPA-registered pesticides, including 

glyphosate, dicamba and glufosinate for weed management. Dicamba would continue to be 

used as currently authorized by EPA for pre-plant applications. Glufosinate use is likely to 

continue to follow the recent trend of increased use associated with the adoption of 

glufosinate-tolerant soybeans and cotton. The environmental risks of pesticide use are assessed 

by EPA in the pesticide registration process and are regularly reevaluated by EPA for each 

pesticide to maintain its registered status under FIFRA. Additionally, pesticide registrants must 

report to EPA the detection of certain amounts of pesticides in surface water, ground water, 

and drinking water as an adverse effect in order to ensure the pesticide continues to meet 

FIFRA requirements for registration. 40 C.F.R. § 159.178(b). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 209 of 946

EPA’s reregistration and registration review process ensures that each registered pesticide 

continues to meet the FIFRA registration standard, i.e., that pesticides will not cause 

unreasonable adverse effects when used as directed on product labels.

Under full deregulation, growers’ use of dicamba and glufosinate for managing hard-to-control 

and herbicide-resistant broadleaf weeds in soybean and cotton fields would be expected to 

increase. Under the No Action Alternative, growers would need to use other practices for 

dealing with hard-to-control and herbicide-resistant broadleaf weeds. These practices would 

likely consist of some combination of herbicide use and traditional tillage. However, the 

specific combination of herbicides used would likely be different than with full deregulation, as 

dicamba would not be able to be used late preemergence or postemergence on DT soybean or 

DGT cotton. Growers would likely use some combination of herbicides currently in use for 

soybean and cotton (see Section II.B.1.d and II.B.2.d).

If the No Action Alternative resulted in increased use of conventional tillage practices for weed 

control, overall adverse surface water impacts may be greater under the No Action Alternative

than under the full deregulation alternative. Tillage causes widespread soil disturbance. Thus, 

erosion, topsoil loss and the resulting sedimentation and turbidity in streams are likely to 

increase with increased tillage. Based on the states’ water quality reports to EPA, which EPA 

makes available through its National Assessment Database, pesticides in general and herbicides 

in particular are a relatively minor contributor to impairment of surface water in the U.S., 

compared to sedimentation/siltation and turbidity (U.S. EPA 2012a). Pesticides accounted for 

less than one percent of reported causes of surface water impairment in all but four of the 17 

leading U.S. soybean-producing states. In those four states, pesticides accounted for 2% to 8% 

of reported causes of impairment. Of the pesticides that were reported as contributing to 

impairment among the 17 leading soybean-producing states, almost all are highly persistent 

chemicals that are no longer registered for use in the U.S. Only one currently used herbicide, 

atrazine, was reported (U.S. EPA 2012a). 

In summary, based on EPA data, herbicides in general are minor contributors to surface water 

impairment in the U.S., while sedimentation/siltation and turbidity are more significant

contributors. The No Action, compared to Deregulation in Whole of DT soybean and DGT 

cotton, would likely result in a different combination of alternative herbicides being used and 

may result in increased tillage to obtain effective weed control. Weed management is a primary 

reason for tillage, and reduced herbicide options due to existing herbicide resistance, in some 

cases, may increase the need for tillage (CAST 2011). Increased tillage could contribute to 

adverse surface water impacts through increased runoff of soil particles to surface water bodies. 

IV.C.3.b. Approval In Whole of DT Soybean, But Not DGT Cotton

As discussed above, approval of the No Action Alternative for DGT cotton is not expected to 

result in significant changes to water quality. 

Land acreage and agronomic practices (including irrigation) associated with soybean production 

would not be substantially impacted by the Deregulation in Whole of DT soybean. Therefore, 

water resources and irrigation associated with soybean production are not likely to be 

substantially affected, and the impacts on water use of the Deregulation in Whole Alternative

would be the same as the No Action Alternative.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 210 of 946

The difference between the Deregulation in Whole and the No Action Alternative for DT 

soybean is expected to be integration of DT soybean into the glyphosate-tolerant soybean 

system using traditional breeding techniques. For those acres where glyphosate-resistant weeds 

may already be present, where application of an herbicide with a different mode-of-action 

would aid in weed control, or for grower implementation of weed resistant management 

practices, the cultivation of soybean containing the DT soybean trait would be an option for 

growers. 

Water quality could be impacted either directly by DT soybean via plant material impacts on 

water resources, or indirectly via impacts from the use of dicamba or tillage practices associated 

with the planting of DT soybean. Conservation tillage, a system that leaves 30% or more of the 

previous crop residue covering the soil when planting another crop has been increasingly 

employed in commercial soybean acres, and helps minimize any impacts of soybean production 

on water quality by reducing soil erosion. 

In terms of potential direct impacts on water quality, DT soybean has been shown to be 

compositionally, agronomically and phenotypically equivalent to conventional soybean and is 

therefore unlikely to have any significant impact on surface water quality. The DMO protein 

contained in DT soybean is a member of the larger family of oxygenase proteins that are 

ubiquitous in plants and bacteria in the environment. The mode-of-action of this family of 

proteins is well known, and the introduced DMO protein itself was derived from a common 

soil bacterium (Stenotrophomonas maltophilia). MON 87708 DMO has been shown to have a high 

level of substrate specificity, and characterization data provided in Appendix G of this 

Environmental Report demonstrate the safety of the MON 87708 DMO protein. Therefore, it 

is unlikely that the presence of MON 87708 DMO protein in DT soybean will have a 

significant impact on water quality.

Under full deregulation of DT soybean, there will be a decreased need for farmers employing 

conventional tillage practices in order to manage certain weed situations. There is a potential 

impact to soil conservation in those situations where tillage has been employed to manage 

resistant weeds (CAST 2011). Dicamba’s complementary and supplementary postemergence 

activity to glyphosate will provide improved postemergence weed management options and 

thus support more sustainable conservation tillage practices because postemergence herbicide 

options are generally preferred by growers (Fawcett and Towery 2002). Tillage causes 

widespread soil disturbance causing erosion and topsoil loss, impacting the sedimentation and 

turbidity of streams. EPA identified sedimentation and turbidity as two of the top 10 causes of 

impairment to surface water in the U.S.; similarly in 2007, EPA identified 

sedimentation/siltation as a leading cause of impairment to rivers and streams in particular 

(U.S. EPA, 2007a; 2009a). EPA has projected conservation tillage to be “the major soil 

protection method and candidate best management practice for improving surface water 

quality” (U.S. EPA, 2002). EPA identifies conservation tillage as the first of its CORE4 

agricultural management practices for water quality protection (U.S. EPA, 2008a). Therefore, 

the Deregulation in Whole and No Action Alternatives are not significantly different regarding 

the impact of the cultivation of DT soybean on water quality.

Under full deregulation of DT soybean, dicamba would be an additional weed management tool 

for managing hard-to-control and herbicide-resistant broadleaf weeds found in soybean fields.

The use of dicamba on soybean would be expected to increase relative to current and historical 

levels of use, up to 2.6 times the maximum historical annual level in 1994. However, potential 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 211 of 946

impacts associated with any increased use of dicamba from the cultivation of DT soybean have 

been adequately assessed by EPA as part of the dicamba Reregistration Eligibility Decision 

(RED); therefore it is reasonably foreseeable that EPA will register this specific use of dicamba 

under FIFRA. EPA considered potential risks associated with dicamba use, including its 

degradate DCSA when appropriate, on surface or ground water using screening level (high-end 

exposure) models to estimate environmental concentrations. The EPA then compared these 

exposure estimates to appropriate endpoints from mammalian, aquatic animal and plant 

ecotoxicity studies, and concluded dicamba meets the FIFRA standard for no unreasonable 

adverse effects on human health and the environment (see Appendices G and H of this 

Environmental Report. The EPA analysis, based on use patterns that exceed the proposed 

single and annual maximum use rates for dicamba on DT soybean, does not take into account 

normal variation in environmental concentrations that can occur, and assumes that greater than 

85% of the watershed is treated with the herbicide at the maximum labeled rate on the same 

day. In addition, the EPA examined and considered available monitoring data as part of the 

dicamba RED, where concentrations of dicamba in ground and surface water were detected at 

levels up to 44 μg/L and 1.76 μg/L, respectively. Furthermore, potential impacts on ground 

and surface water from dicamba use on DT soybean will be considered by EPA as part of 

Monsanto’s pending application to register the use of dicamba on DT soybean, and must meet 

the FIFRA standard for no unreasonable adverse effects on human health or the environment 

prior to approval. 

It is foreseeable that the frequency of dicamba detections in ground and surface water could 

increase as a result of the cultivation of DT soybean; however, levels of dicamba in water are 

not expected to increase above the levels already evaluated and considered by EPA. Existing 

monitoring data provides additional support that water resources will not be impacted from any 

potential increase in dicamba use. Monsanto has compiled publicly available surface and 

ground water monitoring data from across the United States from 1990 through 2010, including 

sampling sites in areas where soybean and corn are grown and where dicamba use has 

historically been most intense (see Appendix C of this Environmental Report. Maximum 

labeled use rates during most of this timeframe (2.8 lb a.e. per acre single maximum and 7.7 lb 

a.e. per acre annual maximum) were much higher than presently allowed rates (1.0 lb a.e. per 

acre single maximum and 2.0 lb a.e. per acre annual maximum) and the rates proposed on 

Monsanto’s dicamba label for use on DT soybean. Therefore, an examination of available 

surface and groundwater monitoring data in these areas during the mid-1990s would be 

indicative of the anticipated levels of dicamba that may occur from the use on DT soybean.

An evaluation of the compiled surface water data from 1994 through 1998 for the major 

soybean areas during the primary dicamba application months of April through July indicates 

that detected levels of dicamba (90th percentile concentration for all samples where dicamba 

was detected58) were less than 1 μg/L. Monitoring data from April through July were evaluated 

because these are the months where the majority of dicamba applications are made to soybean 

(preemergence) and corn (pre- and postemergence), and when surface water concentrations 

from with these applications would be expected to peak. The maximum level of dicamba in 

 

58 EPA uses the 90th percentile as the relevant high-end endpoint when analyzing water monitoring data.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 212 of 946

surface water during this same timeframe was 9.4 μg/L. Similarly, the evaluation of the 

groundwater data for major soybean growing areas from 1994 through 1998 indicates that 

detected levels of dicamba (90th percentile concentration of all samples where dicamba was 

detected) were 0.25 μg/L or less. The maximum level of dicamba in groundwater during this 

same timeframe was 2.2 μg/L. Furthermore, dicamba has been used in crops grown in rotation 

with soybean (e.g., cotton and corn) for decades with no significant adverse effects reported.

Considering the available monitoring data for ground and surface water during the period of 

dicamba’s most intensive use and when application rates were significantly higher than the rates 

proposed for use on DT soybean, it is reasonable to assume that levels in ground and surface 

water that may result from the use of dicamba on DT soybean would be below the levels (highend exposure modeling and monitoring data) considered by the EPA in the dicamba RED, and 

where EPA concluded would no unreasonable adverse effects on human health or the 

environment. 

Based on the above, the Deregulation in Whole and No Action Alternatives are similar 

regarding their potential impact on surface and ground water quality from the use of dicamba 

on DT soybean.

IV.C.3.c. Approval in Whole of DGT cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to water quality. 

As discussed in Section IV.B.2.b, DGT cotton would not change cultivation practices for 

cotton production, nor would it increase the total acres and range of U.S. cotton production 

areas. Therefore, Deregulation in Whole of DGT cotton would not change the current use of 

irrigation practices in commercial cotton production, and the impacts on water use of the 

Deregulation in Whole Alternative would be the same as the No Action Alternative.

Conservation tillage has been increasingly employed on commercial herbicide-tolerant cotton 

acres and helps minimize the impact of cotton production on water quality by reducing erosion 

(Price et al. 2011). It is therefore anticipated that the introduction of DGT cotton will help 

maintain current levels of conservation tillage adoption and may further increase the number of 

cotton acres in conservation tillage, resulting in improved water quality. 

Under full deregulation, dicamba would be an additional weed management tool for managing 

hard-to-control and herbicide-resistant broadleaf weeds found in cotton fields. As discussed in 

Section IV.A.2, the use of dicamba on cotton may increase by approximately 5.2 million 

pounds a.e. annually; combined with current crop uses of approximately 3.8 million pounds a.e. 

dicamba, the total would still be less than the maximum historical pounds of dicamba in 1994 

(See Table A-7 in Appendix A). The increase in dicamba usage is expected to displace some of 

the current herbicide usage in cotton today, particularly applications of diuron, fomesafen, 

fluometuron, and paraquat. Dicamba offers a more benign human health and environmental 

profile in comparison to some of the alternative non-glyphosate herbicides currently available

to cotton growers (see Appendix A).

If EPA approves the registration of dicamba for use on DGT cotton, then it will have reviewed 

the data and found no unreasonable adverse environmental impacts from that use. Dicamba 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 213 of 946

use on DGT cotton will only be permitted following EPA approval. The EPA considered 

potential risks associated with dicamba use, including its degradate DCSA on surface or ground 

water using screening level (high-end theoretical exposure) models to estimate potential 

environmental concentrations of dicamba and DCSA. The EPA then compared these exposure 

estimates to appropriate endpoints from mammalian, aquatic animal and plant ecotoxicity 

studies conducted with dicamba, and concluded dicamba meets the FIFRA standard for no 

unreasonable adverse effects on human health and the environment. The EPA modeling 

predictions and the NAWQA monitoring results (see Appendices E and F of this 

Environmental Report) demonstrate that dicamba concentrations that might occur in drinking 

water are orders of magnitude below the lifetime Health Advisory Level (HAL) of 4000 ug/L 

for dicamba. Thus, confirming that the potential risk of dicamba leaching into groundwater or 

running off into surface water is low and does not threaten human health or acceptable water

quality. In addition, dicamba has been used in crops grown in rotation with cotton (e.g., corn

and soybean) for decades with no significant adverse effects reported.

Furthermore, potential impacts on ground and surface water from dicamba use on DGT cotton 

will be considered by EPA as part of Monsanto’s pending application to register the use of a 

low volatility DGA dicamba formulation on DGT cotton, and must meet the FIFRA standard 

for no unreasonable adverse effects on human health or the environment prior to approval. 

It is possible that the frequency of dicamba detections in ground and surface water could 

increase as a result of the cultivation of DGT cotton. However, the EPA models for dicamba 

movement and accumulation assume greater than 85% of the acres are treated with dicamba 

and the maximum use rates on DGT cotton would be less than or equal to rates previously 

evaluated by EPA. Therefore, the levels of dicamba in water following the introduction of 

DGT cotton may increase, but are not expected to increase above the levels already evaluated 

and considered acceptable by EPA. See Appendix C of this Environmental Report for 

additional information on the EPA models use to evaluate dicamba. 

Considering the available monitoring data for levels of dicamba in ground and surface water 

during the period of dicamba’s most intensive use (1994) and that application rates at that time 

were substantially higher than the rates proposed for use on DGT cotton, it is reasonable to 

conclude that levels of dicamba in ground and surface water that may result from the use of 

dicamba on DGT cotton would be below the levels (high-end exposure modeling and 

monitoring data) considered by the EPA in the dicamba RED. In the RED assessment, EPA 

concluded that all uses of dicamba contemplated would not result in an unreasonable adverse 

effect on human health or the environment.

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. Glufosinate use on many crops, including cotton, was 

reviewed by the EPA as part of the food, feed, and environmental safety reassessment in 2000 

(U.S. EPA 2003). In addition, glufosinate has been used over-the-top of glufosinate-tolerant 

crops since 1995 with no significant adverse effects reported. Glufosinate is currently labeled 

for in-crop application with glufosinate-tolerant cotton from emergence through early bloom 

growth stage (Bayer Crop Science 2007). The use pattern and rate of glufosinate on DGT

cotton will follow the existing glufosinate-tolerant cotton uses outlined on the glufosinate 

herbicide label. Currently glufosinate is undergoing Registration Review at EPA with with a 

forthcoming final decision scheduled in 2013 (U.S. EPA 2009d). It is likely that EPA will 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 214 of 946

approve the continued use of glufosinate in the marketplace upon completion of the 

Registration Review process. 

Therefore, the Deregulation in Whole and No Action Alternatives are similar regarding their 

potential impact on ground water quality from the use of dicamba on DGT cotton.

IV.C.3.d. Approval in whole of both DT soybean and DGT cotton

The difference between the Deregulation in Whole and the No Action Alternative for DT 

soybean and DGT cotton is expected to be integration of DT soybean and DGT cotton into 

the glyphosate-tolerant soybean and cotton systems using traditional breeding techniques. For 

those acres where glyphosate-resistant weeds may already be present, where application of an 

herbicide with a different mode-of-action would aid in weed control, or for grower 

implementation of weed resistant management practices, the cultivation of soybean or cotton 

containing the DT soybean or DGT cotton traits would be an option for growers. 

Approval in whole of DT soybean and DGT cotton would not change cultivation practices for 

soybean or cotton production, nor would it increase the total acres and range of U.S. soybean 

and cotton production areas. Therefore, Deregulation in Whole of DT soybean and DGT 

cotton would not change the current use of irrigation practices in commercial soybean and 

cotton production, and the impacts on water use of the Deregulation in Whole Alternative

would be the same as the No Action Alternative.

Water quality could be impacted either directly by DT soybean and DGT cotton via plant 

material impacts on water resources, or indirectly via impacts from the use of dicamba or tillage 

practices associated with the planting of DT soybean and DGT cotton. Conservation tillage, a 

system that leaves 30% or more of the previous crop residue covering the soil when planting 

another crop has been increasingly employed in commercial soybean acres, and helps minimize 

any impacts of soybean production on water quality by reducing soil erosion. 

In terms of potential direct impacts on water quality, DT soybean and DGT cotton have been 

shown to be compositionally, agronomically and phenotypically equivalent to conventional 

soybean and cotton and therefore are unlikely to have any significant impact on surface water 

quality. 

Under full deregulation of DT soybean and DGT cotton, there will be a decreased need for 

farmers employing conventional tillage practices in order to manage certain weed situations. 

There is a potential impact to soil conservation in those situations where tillage has been 

employed to manage resistant weeds (CAST 2011). Dicamba’s complementary and 

supplementary postemergence activity to glyphosate will provide improved postemergence 

weed management options and thus support more sustainable conservation tillage practices 

because postemergence herbicide options are generally preferred by growers (Fawcett and 

Towery 2002). Tillage causes widespread soil disturbance causing erosion and topsoil loss, 

impacting the sedimentation and turbidity of streams. EPA identified sedimentation and 

turbidity as two of the top 10 causes of impairment to surface water in the U.S.; similarly in 

2007, EPA identified sedimentation/siltation as a leading cause of impairment to rivers and 

streams in particular (U.S. EPA 2007b; 2009c). EPA has projected conservation tillage to be 

“the major soil protection method and candidate best management practice for improving 

surface water quality” (U.S. EPA 2007a). EPA identifies conservation tillage as the first of its 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 215 of 946

CORE4 agricultural management practices for water quality protection (U.S. EPA 2013d). 

Therefore, the Deregulation in Whole and No Action Alternatives are not significantly different 

regarding the impact of the cultivation of DT soybean and DGT cotton on water quality.

Under full deregulation, dicamba would be an additional weed management tool for managing

hard-to-control and herbicide-resistant broadleaf weeds found in soybean and cotton fields.

The use of dicamba on soybean would be expected to increase relative to current and historical 

levels of use, and the use of dicamba on cotton would be expected to increase relative to 

current levels but stay below the historical maximum. Potential impacts associated with any 

increased use of dicamba from the cultivation of DT soybean and DGT cotton have been 

adequately assessed by EPA as part of the dicamba Reregistration Eligibility Decision (RED); 

therefore it is reasonably foreseeable that EPA will register this specific use of dicamba under 

FIFRA. EPA considered potential risks associated with dicamba use, including its degradate 

DCSA when appropriate, on surface or ground water using screening level (high-end exposure) 

models to estimate environmental concentrations. The EPA then compared these exposure 

estimates to appropriate endpoints from mammalian, aquatic animal and plant ecotoxicity 

studies, and concluded dicamba meets the FIFRA standard for no unreasonable adverse effects 

on human health and the environment. The EPA analysis, based on use patterns that exceed 

the proposed single and annual maximum use rates for dicamba, does not take into account 

normal variation in environmental concentrations that can occur, and assumes that greater than 

85% of the water shed is treated with the herbicide at the maximum labeled rate on the same 

day. In addition, the EPA examined and considered available monitoring data as part of the 

dicamba RED, where concentrations of dicamba in ground and surface water were detected at 

levels up to 44 μg/L and 1.76 μg/L, respectively. Furthermore, potential impacts on ground 

and surface water from dicamba use on DT soybean and DGT cotton will be considered by 

EPA as part of Monsanto’s pending application to register the use of dicamba on DT soybean 

and DGT cotton, and must meet the FIFRA standard for no unreasonable adverse effects on 

human health or the environment prior to approval. 

It is foreseeable that the frequency of dicamba detections in ground and surface water could 

increase as a result of the cultivation of DT soybean and DGT cotton; however, levels of 

dicamba in water are not expected to increase above the levels already evaluated and considered 

by EPA. Existing monitoring data provides additional support that water resources will not be 

impacted from any potential increase in dicamba use. Monsanto has compiled publicly 

available surface and ground water monitoring data from across the United States from 1990 

through 2010, including sampling sites in areas where soybean and corn are grown and where 

dicamba use has historically been most intense (see Appendices C and F of this Environmental 

Report). Maximum labeled use rates during most of this timeframe (2.8 lb a.e. per acre single 

maximum and 7.7 lb a.e. per acre annual maximum) were much higher than presently allowed 

rates (1.0 lb a.e. per acre single maximum and 2.0 lb a.e. per acre annual maximum) and the 

rates proposed on Monsanto’s dicamba label for use on DT soybean and DGT cotton. 

Therefore, an examination of available surface and groundwater monitoring data in these areas 

during the mid-1990s would be indicative of the anticipated levels of dicamba that may occur 

from the use on DT soybean. 

An evaluation of the compiled surface water data from 1994 through 1998 for the major 

soybean areas during the primary dicamba application months of April through July indicates 

that detected levels of dicamba (90th percentile concentration for all samples where dicamba 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 216 of 946

was detected59) were less than 1 μg/L. Monitoring data from April through July were evaluated 

because these are the months where the majority of dicamba applications are made to soybean 

(preemergence) and corn (pre- and postemergence), and when surface water concentrations 

from with these applications would be expected to peak. The maximum level of dicamba in 

surface water during this same timeframe was 9.4 μg/L. Similarly, the evaluation of the 

groundwater data for major soybean growing areas from 1994 through 1998 indicates that 

detected levels of dicamba (90th percentile concentration of all samples where dicamba was 

detected) were 0.25 μg/L or less. The maximum level of dicamba in groundwater during this 

same timeframe was 2.2 μg/L. 

Considering the available monitoring data for ground and surface water during the period of 

dicamba’s most intensive use and when application rates were significantly higher than the rates 

proposed for us on DT soybean, it is reasonable to assume that levels in ground and surface 

water that may result from the use of dicamba on DT soybean would be below the levels (highend exposure modeling and monitoring data) considered by the EPA in the dicamba RED, and 

where EPA concluded would have no unreasonable adverse effects on human health or the 

environment. Compiled water monitoring data were not inclusive of cotton production areas, 

except for surface water sources in the Delta region, however the high-end modeling predicted 

concentrations evaluated by EPA included cropping scenarios representative of cotton growing 

region.

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. Glufosinate use on many crops, including cotton, was 

reviewed by the Environmental Protection Agency (EPA) as part of the food, feed, and 

environmental safety reassessment in 2000 (U.S. EPA 2003). In addition, glufosinate has been 

used over-the-top of glufosinate-tolerant crops since 1995 with no significant adverse effects 

reported. Glufosinate is currently labeled for in-crop application with glufosinate-tolerant 

cotton from emergence through early bloom growth stage (Bayer Crop Science 2007; 2013). 

The use pattern and rate of glufosinate on DGT cotton will follow the existing glufosinatetolerant cotton uses outlined on the glufosinate herbicide label. Currently glufosinate is 

undergoing Registration Review at EPA with a forthcoming final decision scheduled in 2013 

(U.S. EPA 2008b; 2009d). It is likely that EPA will approve the continued use of glufosinate in 

the marketplace upon completion of the Registration Review process. Therefore, Monsanto 

will not pursue any changes in the glufosinate label, use pattern, or the established tolerances 

for its use on DGT cotton.

Because conservation tillage acres are likely to remain the same, or potentially increase, on 

soybean and cotton acreage with the introduction of DT soybean and DGT cotton, 

corresponding benefits to surface water are expected as compared to the No Action 

Alternative. Therefore, the approval in whole and No Action Alternatives are similar regarding 

their potential impact on surface and ground water quality from the use of dicamba on DT

soybean and DGT cotton and glufosinate on DGT cotton.

 

59 EPA uses the 90th percentile as the relevant high-end endpoint when analyzing water monitoring data.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 217 of 946

IV.C.4. Air Quality Impacts

IV.C.4.a. No action alternative for both DT soybean and DGT cotton

Under the No Action Alternative, both DT soybean and DGT Cotton would continue to be 

regulated by APHIS. Several agricultural practices have the potential to cause negative impacts 

to air quality. Agricultural emission sources include smoke from agricultural burning, tillage, 

heavy equipment emissions, pesticide drift from spraying, and indirect emissions from carbon 

dioxide and nitrous oxide emissions from the use of nitrogen fertilizer and degradation of 

organic materials (Aneja et al. 2009; U.S. EPA 2010c; USDA-NRCS, 2006; U.S. EPA, 2011d).

As discussed above, compared with full deregulation of DT soybean and DGT cotton, the No 

Action Alternative may result in increased tillage, and decreases in conservation tillage. EPA 

reports conservation tillage as an agricultural practice that “increases carbon storage through 

enhanced soil sequestration” and that “may reduce energy-related CO2emissions from farm 

equipment” (U.S. EPA 2010a). When carbon is stored, it is not available to be emitted in the 

form of carbon dioxide (CO2), a greenhouse gas. Thus, the No Action Alternative may result in 

increased tillage, which could cause some adverse air quality impacts compared with full 

deregulation.

Adoption of GE soybean and cotton varieties is expected to continue. To the extent that the 

adoption and cultivation of GE soybean and cotton varieties allows the grower to implement 

soil conservation practices, air quality improvements associated with these practices would be 

expected to follow. This would include both direct air quality effects, e.g., emissions from farm 

equipment, airborne soil erosion and pesticide drift, as well as indirect air quality effects, e.g., 

nitrous oxide emissions associated with the use of nitrogen fertilizers (Aneja et al. 2009; USDANRCS, 2006; EPA, 2011d). Under the No Action Alternative, growers would still likely 

practice conservation tillage, and in certain situations they would rely on tillage and/or other 

herbicides used in soybean and cotton production. Other herbicide-tolerant soybean and 

cotton events have been deregulated by APHIS or have been submitted to APHIS for 

deregulation. These events and their companion herbicides may be used to promote 

conservation tillage practices under the No Action Alternative. Therefore, the No Action and 

Deregulation in Whole Alternatives may not be significantly different regarding their potential 

impact on air quality.

IV.C.4.b. Approval in whole of DT soybean, but not DGT cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes to air quality. 

The difference between the Deregulation in Whole and the No Action Alternative is expected 

to be the integration of DT soybean into the glyphosate-tolerant soybean system using 

traditional breeding techniques. For those acres where glyphosate-resistant weeds may already 

be present, where application of an herbicide with a different mode-of-action would aid in 

weed control, or for grower implementation of weed resistant management practices, the 

cultivation of soybean containing the DT soybean trait would be an option for growers. 

General management strategies currently employed to manage and mitigate herbicide drift and 

volatilization would not differ from those currently employed throughout the industry under 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 218 of 946

the No Action Alternative. Depending upon the site-specific application requirements, growers 

would continue to select from a range of strategies to effectively reduce drift and volatilization 

currently provided and enforced on herbicide labels (see e.g., Monsanto, 2010; Bayer, 2011b). 

Agricultural practices are not expected to change significantly with the introduction of DT 

soybean. A discussion of the agricultural practices associated with soybean production in the 

U.S. is provided in Section II.B.1.c, and includes discussion of cultural, mechanical and 

herbicide practices for weed management. Deregulation of DT soybean is expected to facilitate 

the trend toward increased adoption of conservation tillage methods by soybean growers 

because conservation tillage (specifically no-till) relies on the use of herbicides to control weeds 

that emerge in a field prior to or after planting the soybean seed into the previous crop stubble, 

thus avoiding disturbance of the soil. DT soybean would help to maintain existing 

conservation tillage practices and facilitate the adoption of conservation tillage practices by 

simplifying weed control options for growers utilizing a non-glyphosate herbicide or where 

there are glyphosate-resistant or hard-to-control broadleaf weeds present. Soybean represents 

the greatest number of acres of the major field crops utilizing conservation tillage and the 

highest percentage of total crop acres devoted to conservation tillage practices (CTIC 2007). 

Considerable benefits to the physical environment, including those related to air quality, are 

obtained from use of conservation tillage methods including (CTIC 2011; USDA-NRCS 2005):

 Dramatic reduction in soil erosion from wind and water;

 Less herbicide, water, and soil runoff from soils improving the quality of 

streams and lakes;

 Overall healthier soils;

 Increased carbon sequestration leading to reduced greenhouse gases;

 Decreased fuel emissions due to reduced use of tractors to plow fields;

 Reduced nitrogen applications (much of which is made from fossil fuels); and

 Less overall water usage for agricultural purposes. 

While Deregulation in Whole of DT soybean may facilitate some trend towards increasing 

conservation tillage, it is not expected to significantly impact air quality. Therefore 

Deregulation in Whole and No Action Alternatives may not be significantly different regarding 

their impacts on air quality. 

IV.C.4.c. Approval in whole of DGT cotton, but not DT soybean

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to air quality. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. For those 

acres where glyphosate-resistant weeds may already be present, where application of a herbicide 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 219 of 946

with a different mode-of-action would aid in weed control, or for grower implementation of 

weed resistant management practices, the cultivation of cotton containing the DGT cotton 

traits would be an option for growers. 

General management strategies currently employed to manage and mitigate herbicide drift and 

volatilization would not differ from those currently employed throughout the industry under 

the No Action Alternative. Depending upon the site-specific application requirements, growers 

would continue to select from a range of strategies to effectively reduce drift and volatilization 

currently provided and enforced on herbicide labels (see e.g., Monsanto, 2010; Bayer, 2011b).

Agricultural practices that may affect air quality are not expected to change substantially with 

the introduction of DGT cotton. Deregulation of DGT cotton is expected to sustain or 

possibly increase current adoption levels of conservation tillage methods by cotton growers 

because conservation tillage (in particular, no-till) relies on the use of herbicides to control

weeds that emerge in a field prior to or after planting the cotton seed into the previous crop 

stubble, thus avoiding disturbance of the soil. DGT cotton would help to maintain existing 

conservation tillage practices and facilitate the adoption of conservation tillage practices by 

simplifying weed control options for growers utilizing a non-glyphosate herbicide where there 

are glyphosate-resistant or hard-to-control broadleaf weeds present. Considerable benefits to 

the physical environment, including those related to air quality, are obtained from use of 

conservation tillage methods including (CTIC 2011; USDA-NRCS 2005):

 Dramatic reduction in soil erosion from wind and water;

 Less herbicide, water, and soil runoff from soils improving the quality of 

streams and lakes;

 Overall healthier soils;

 Increased carbon sequestration leading to reduced greenhouse gases;

 Decreased fuel emissions due to reduced use of tractors to plow fields;

 Reduced nitrogen applications (much of which is made from fossil fuels); and

 Less overall water usage for agricultural purposes. 

While Deregulation in Whole of DGT cotton may facilitate some trend towards increasing 

conservation tillage, it is not expected to significantly impact air quality. In summary, compared 

with the No Action Alternative, the Deregulation in Whole Alternative of the DGT cotton 

alternative is expected to result in localized and short-term increases in emissions from 

application of dicamba and glufosinate, and localized and short-term decreases in emissions of 

other herbicides used in cotton and/or decreases in emissions from vehicles and dust resulting 

from higher levels of conservation tillage. Thus, the Deregulation in Whole and No Action 

Alternatives may not be significantly different regarding their impacts on air quality.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 220 of 946

IV.C.4.d. Approval in whole of both DT soybean and DGT cotton

The difference between the Deregulation in Whole and the No Action Alternative is expected 

to be the integration of DT soybean and DGT cotton into the glyphosate-tolerant soybean and 

cotton systems using traditional breeding techniques. For those acres where glyphosateresistant weeds may already be present, where application of an herbicide with a different 

mode-of-action would aid in weed control, or for grower implementation of weed resistant 

management practices, the cultivation of soybean or cotton containing the DT soybean or 

DGT cotton traits would be an option for growers. 

General management strategies currently employed to manage and mitigate herbicide drift and 

volatilization would not differ from those currently employed throughout the industry under 

the No Action Alternative. Depending upon the site-specific application requirements, growers 

would continue to select from a range of strategies to effectively reduce drift and volatilization 

currently provided and enforced on herbicide labels (see e.g., Monsanto, 2010; Bayer, 2011b). 

Agricultural practices are not expected to change significantly with the introduction of DT 

soybean and DGT cotton. Deregulation of DT soybean and DGT cotton is expected to 

facilitate the trend toward increased adoption of conservation tillage methods by soybean and 

cotton growers because conservation tillage (specifically no-till) relies on the use of herbicides 

to control weeds that emerge in a field prior to or after planting the soybean seed into the 

previous crop stubble, thus avoiding disturbance of the soil. DT soybean and DGT cotton 

would help to maintain existing conservation tillage practices and facilitate the adoption of 

conservation tillage practices by simplifying weed control options for growers utilizing a nonglyphosate herbicide or where there are glyphosate-resistant or hard-to-control broadleaf weeds 

present. Considerable benefits to the physical environment, including those related to air 

quality, are obtained from use of conservation tillage methods including (CTIC 2011; USDANRCS 2005):

 Dramatic reduction in soil erosion from wind and water;

 Less herbicide, water, and soil runoff from soils improving the quality of 

streams and lakes;

 Overall healthier soils;

 Increased carbon sequestration leading to reduced greenhouse gases;

 Decreased fuel emissions due to reduced use of tractors to plow fields;

 Reduced nitrogen applications (much of which is made from fossil fuels); and

 Less overall water usage for agricultural purposes. 

While Deregulation in Whole of DT soybean and DGT cotton may facilitate some trend 

towards increasing conservation tillage, it is not expected to significantly impact air quality. In 

summary, compared with the No Action Alternative, the Deregulation in Whole Alternative is 

expected to result in localized and short-term increases in emissions from application of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 221 of 946

dicamba and glufosinate, and localized and short-term decreases in emissions of other 

herbicides used in cotton and/or decreases in emissions from vehicles and dust resulting from 

higher levels of conservation tillage. Thus, the Deregulation in Whole and No Action 

Alternatives may not be significantly different regarding their impacts on air quality. 

IV.C.5. Climate Change Impacts

IV.C.5.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially cultivated (both GE and 

non-GE) soybeans and cotton are expected to remain the same under the No Action 

Alternative. 

Under the No Action Alternative, contributions of agriculture, including soybean and cotton 

production, to greenhouse gas emissions would be expected to continue. Climate change is 

likely to impact agriculture, including cotton production; however, the specific impacts are 

speculative.

Conservation tillage practices used in U.S. soybean and cotton production have been identified 

as providing climate change benefits (Brenner et al., 2001). Conservation tillage, in addition to 

providing benefits to soil quality, has the benefit of increasing carbon sequestration in soils. 

Conservation tillage is also associated with reduced carbon emissions from lower farm 

equipment operations. Switching from conventional tillage to a no-till corn-soybean rotation in 

Iowa, for example, has been estimated to increase carbon sequestration by 550 kg/hectare (485 

lb./acre) per year (Towery and Werblow 2010; Paustian et al., 2000; Brenner et al., 2001).

Under the No Action Alternative, current impacts on climate change associated with soybean 

and cotton production would not be affected. Agronomic practices associated with soybean

and cotton production such as tillage, cultivation, irrigation, pesticide application, fertilizer 

applications and use of agriculture equipment would continue on soybeans and cotton grown 

throughout the region.

IV.C.5.b. Approval in Whole of DT Soybean, But Not DGT Cotton

As discussed, approval of the No Action Alternative for DGT cotton is not expected to result 

in significant climate change impacts.

A determination of nonregulated status of DT soybean is not expected to result in changes in 

the current soybean cropping practices, with the exception of potential changes in the use of 

certain herbicides for weed management. DT soybean is essentially indistinguishable from 

other soybean varieties in terms of agronomic characteristics and cultivation practices. As DT 

soybean is essentially equivalent to other GE herbicide-tolerant and non-GE soybeans, no 

changes in agronomic practices (such as crop rotation), cultivation, geographic range, 

seasonality or insect susceptibility, are expected to occur. Based on individual grower needs, DT 

soybean could provide growers with an alternative to intensive tillage practices that may be used 

to address herbicide weed resistance challenges. This in turn could reduce the need for 

conventional tillage practices that may impact conservation tillage practices. The continued use 

of conservation tillage associated with GE crops may reduce GHG emissions as a result of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 222 of 946

increased carbon sequestration in soils, decreased fuel consumption, and the reduction of 

nitrogen soil amendments (Towery and Werblow 2010). 

Based on the above information, the availability of DT soybean is not expected to change the 

cultivation or agronomic practices or agricultural land acreage associated with growing soybean. 

It may provide some benefit to reducing GHG contributions to climate change in the form of 

sustaining the adoption of conservation tillage practices, but overall the impacts to climate 

change is expected to be similar to the No Action Alternative. 

IV.C.5.c. Approval in whole of DGT cotton, but not DT soybean

As discussed, approval of the No Action Alternative for DT soybean is not expected to result 

in significant climate change impacts.

A determination of nonregulated status of DGT cotton is not expected to result in changes in 

the current cotton cropping practices, with the exception of potential changes in the use of 

certain herbicides for weed management. DGT cotton is essentially indistinguishable from 

other cotton varieties in terms of agronomic characteristics and cultivation practices. As DGT 

cotton is essentially equivalent to other GE herbicide-tolerant and non-GE cotton, no changes 

in agronomic practices (such as crop rotation), cultivation, geographic range, seasonality or 

insect susceptibility, are expected to occur. Based on individual grower needs, DGT cotton 

could provide growers with an alternative to intensive tillage practices that may be used to 

address herbicide weed resistance challenges. This in turn this could reduce the need for 

conventional tillage practices that may impact conservation tillage practices. The continued use 

of conservation tillage associated with GE crops may reduce GHG emissions as a result of 

increased carbon sequestration in soils, decreased fuel consumption, and the reduction of 

nitrogen soil amendments (Towery and Werblow 2010). 

Based on the above information, the availability of DGT cotton is not expected to change the 

cultivation or agronomic practices or agricultural land acreage associated with growing cotton. 

It may provide some benefit to reducing GHG contributions to climate change in the form of 

sustaining the adoption of conservation tillage practices, but overall the impacts to climate 

change is expected to be similar to the No Action Alternative. 

IV.C.5.d. Approval in whole of both DT soybean and DGT cotton

A determination of nonregulated status of DT soybean and DGT cotton is not expected to 

result in changes in the current cotton cropping practices, with the exception of potential 

changes in the use of certain herbicides for weed management. DT soybean and DGT cotton 

are essentially indistinguishable from other soybean and cotton varieties in terms of agronomic 

characteristics and cultivation practices. As DT soybean and DGT cotton are essentially 

equivalent to other GE herbicide-tolerant and non-GE soybeans and cotton, no changes in 

agronomic practices (such as crop rotation), cultivation, geographic range, seasonality or insect 

susceptibility, are expected to occur. Based on individual grower needs, DT soybean and DGT 

cotton could provide growers with an alternative to intensive tillage practices that may be used 

to address herbicide weed resistance challenges. This in turn this could reduce the need for 

conventional tillage practices that may impact conservation tillage practices. The continued use 

of conservation tillage associated with GE crops may reduce GHG emissions as a result of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 223 of 946

increased carbon sequestration in soils, decreased fuel consumption, and the reduction of 

nitrogen soil amendments (Towery and Werblow 2010). 

Based on the above information, the availability of DT soybean and DGT cotton is not 

expected to change the cultivation or agronomic practices or agricultural land acreage 

associated with growing soybeans and cotton. It may provide some benefit to reducing GHG 

contributions to climate change in the form of sustaining the adoption of conservation tillage 

practices, but overall the impacts to climate change is expected to be similar to the No Action 

Alternative. 

IV.D. BIOLOGICAL IMPACTS FROM DT SOYBEAN & DGT COTTON

IV.D.1. Animal Communities 

IV.D.1.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, both DT soybean and DGT Cotton would continue to be 

regulated by APHIS. The availability and usage of commercially cultivated (both GE and nonGE) soybean and cotton are expected to remain the same under the No Action Alternative. 

Under this alternative DT soybean and DGT Cotton would not become integrated into the 

glyphosate-tolerant soybean and cotton systems and dicamba use would likely remain similar to 

today’s use pattern in soybean and cotton. Adding alternative herbicides with different modesof-action into the glyphosate-tolerant systems to manage the development of glyphosateresistant weeds and control glyphosate-resistant weeds would continue to remain an option. 

Additionally, conventional tillage may increase in some instances as an additional means to 

control problematic weeds. 

Currently herbicides are used on nearly all (~98%) soybean acres, and over 35 different 

herbicide active ingredients are registered and available for use by soybean growers to control 

weeds (See Section II.B.1.d). Currently herbicides are used on nearly all (>99%) cotton acres, 

and approximately 39 million pounds of 30 different herbicides are applied pre- or 

postemergence in cotton production (Monsanto, 2012) (See Section II.B.2.d). The use of 

herbicides in both soybean and cotton production is expected to continue to increase as more 

growers adopt diversified weed management strategies to combat hard-to-control herbicideresistant weeds. Although all herbicides must meet the FIFRA standard of no unreasonable 

adverse effects to humans or the environment, some available herbicides may pose greater 

potential risks to animals or insects than dicamba; moreover, conventional tillage practices may 

increase as a result of weed management challenges. Increased use of tillage could have a small 

adverse impact on wildlife, as the crop residues that remain with the use of conservation tillage 

may provide shelter and food for wildlife, such as game birds and small animals (CTIC 2011).

IV.D.1.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes to animal communities. 

The difference between the No Action and the Deregulation in Whole Alternatives for DT 

soybean would be the gradual integration of the dicamba-tolerant event DT soybean with the 

current glyphosate-tolerant soybean systems using traditional breeding techniques. As 
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discussed in Section IV.B.1, under the Deregulation in Whole Alternative, the cultivation of DT 

soybean is not expected to impact soybean agronomic practices, with the exception of a change 

in herbicide use pattern. Cultivation of DT soybean would not alter agronomic inputs or the 

number of soybean acres under cultivation, and will help maintain current levels of 

conservation tillage adoption and may have a small positive effect on the use of conservation 

tillage. 

Potential Impacts from the Genetic Modification. Potential impacts from dietary exposure 

to DT soybean are discussed in detail in Sections IV.E.1 and IV.F. All the information in 

Sections IV.E.1 and IV.F.1 is relevant to dietary exposure for any animals that may consume 

DT soybean. As discussed in those sections, there is no meaningful risk to animal or human 

health from dietary exposure to the MON 87708 DMO protein. There are no known toxic 

properties associated with the MON 87708 DMO protein. Furthermore, grain and forage 

produced by DT soybean is compositionally equivalent to commercially cultivated soybean, 

whether or not it is treated with dicamba. Additional information on the safety of the 

MON 87708 DMO protein and composition of DT soybean grain and forage, as detailed in 

Appendix G of this Environmental Report indicate that the effects to mammals that consume 

DT soybean seed would be no different than those possible from the consumption of 

commercially cultivated soybean. Similarly, the impact to birds or other animals, including 

migratory birds and animals that may consume soybean forage or seed from DT soybean would 

be no different than possible impacts from commercially cultivated soybean. During field trials 

with DT soybean, no biologically relevant changes in arthropod feeding damage were observed 

(see Appendix G of this Environmental Report) indicating similar arthropod susceptibility for 

DT soybean compared to commercially cultivated soybean. DT soybean exhibits no 

differences in toxic effects on insects or other animals as compared to commercially cultivated 

soybean. In addition, the cultivation of DT soybean does not impact the nutritional quality, 

safety, or availability of animal feed derived from DT soybean (see Section IV.F.). 

Potential Impacts from Dicamba. To support the introduction of DT soybean, Monsanto 

has submitted to EPA an application to amend EPA Reg. No. 524-582, a low-volatility DGA 

salt formulation, to register a new use pattern for dicamba. The current and proposed uses are 

summarized in Table IV.A-1 (see Section IV.A.1). However, a comprehensive evaluation and 

risk assessment conducted by EPA concluded that dicamba has low toxicity to mammals, is not 

a carcinogen, does not adversely affect reproduction and development, and does not 

bioaccumulate in mammals (U.S. EPA 2009a; d). An ecotoxicological risk assessment 

concluded that the use of dicamba does not pose an unreasonable risk of adverse effects to 

non-target species, such as birds and fish, when used according to label directions, nor does it 

pose an unreasonable risk of adverse effects to insects outside of the application area (U.S. 

EPA 2009a; d). Furthermore, outside the cultivated cotton field, dicamba is unlikely to affect 

forbs and beneficial arthropods that are dependent on plants for survival (U.S. EPA 2009a; d). 

In summary, in terms of potential impacts to animal communities, including insects, beneficial 

arthropods, and all other animals that live in or near soybean fields containing DT soybean, the 

difference between the No Action and Deregulation in Whole Alternatives is primarily the 

difference in the types of herbicides that may be used. As with the No Action Alternative, use 

of herbicides is expected to increase as more growers adopt diversified weed management 

strategies to combat hard-to-control and herbicide-resistant weeds, but dicamba is expected to 

displace some herbicides that would otherwise be used, and which could have a more 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 225 of 946

significant environmental footprint. EPA has determined that when herbicides are used in 

accordance with their labels, no unreasonable adverse impacts will result. As discussed above, 

EPA’s conclusions are based on comprehensive evaluations and risk assessments. Compared 

to the Deregulation in Whole Alternative, the No Action Alternative may pose a small increase 

in adverse impacts on animal communities if it results in increased tillage, because crop residue

provides shelter and food for wildlife, such as game birds and small animals (CTIC 2011). 

IV.D.1.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to animal communities. 

The difference between the No Action and the Deregulation in Whole Alternatives for DGT 

cotton would be the gradual integration of the dicamba and glufosinate-tolerant event DGT 

cotton with the current glyphosate-tolerant cotton systems using traditional breeding 

techniques. As discussed in Section IV.B.2, the cultivation of DGT cotton is not expected to 

impact cotton agronomic practices, with the exception of a change in herbicide use pattern. 

Cultivation of DGT cotton would not alter agronomic inputs or the number of cotton acres 

under cultivation, and will help maintain current levels of conservation tillage adoption and may 

have a small positive effect on the use of conservation tillage. 

Potential Impacts from the Genetic Modification. Potential impacts from dietary exposure 

to DGT cotton are discussed in detail in Sections IV.E.1 and IV.F. Except for the discussion 

specific to cottonseed oil and linters in Section IV.F.2, all the information in Sections IV.E.1 

and IV.F is relevant to dietary exposure for any animals that may consume DGT cotton. As 

discussed in those sections, there is no meaningful risk to animal or human health from dietary 

exposure to MON 88701 DMO or PAT (bar). There are no known toxic properties associated 

with MON 88701 DMO or PAT (bar). Furthermore, the seed produced by DGT cotton is 

compositionally equivalent to commercially cultivated cotton, whether or not it is treated with 

dicamba and/or glufosinate. This information on the safety of MON 88701 DMO and PAT 

(bar) and composition of DGT cottonseed, as detailed in Appendix G of this Environmental 

Report, indicate that the effects to mammals that consume DGT cotton seed would be no 

different than those possible from the consumption of commercially cultivated cotton. 

Similarly, the impact to birds or other animals, including migratory birds and animals that may 

consume cottonseed from DGT cotton would be no different than possible impacts from 

commercially cultivated cotton. During field trials with DGT cotton, no biologically relevant 

changes in arthropod feeding damage were observed (see Appendix G of this Environmental 

Report) indicating similar arthropod susceptibility for DGT cotton compared to commercially 

cultivated cotton. DGT cotton exhibits no differences in toxic effects on insects or other 

animals as compared to commercially cultivated cotton. In addition, the cultivation of DGT 

cotton does not impact the nutritional quality, safety, or availability of animal feed derived from 

DGT cotton (see Section IV.F). 

Potential Impacts from Dicamba. To support the introduction of DGT cotton, Monsanto 

has submitted an application to EPA to amend Registration number 524-582, a low-volatility 

DGA salt formulation, to remove all preemergence planting restrictions (application intervals, 

rainfall, and geographic) and to allow in-crop postemergence dicamba applications to DGT 

cotton. However, a comprehensive evaluation and risk assessment conducted by EPA 

concluded that dicamba has low toxicity to mammals, is not a carcinogen, does not adversely 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 226 of 946

affect reproduction and development, and does not bioaccumulate in mammals (U.S. EPA 

2009a; d). An ecotoxicological risk assessment concluded that the use of dicamba does not 

pose an unreasonable risk of adverse effects to non-target species, such as birds and fish, when 

used according to label directions, nor does it pose an unreasonable risk of adverse effects to 

insects outside of the application area (U.S. EPA 2009b; a). Furthermore, outside the cultivated 

cotton field, dicamba is unlikely to affect forbs and beneficial arthropods that are dependent on 

plants for survival (U.S. EPA 2009a; d). As with the No Action Alternative, use of herbicides is 

expected to increase as more growers adopt diversified weed management strategies to combat 

hard-to-control and herbicide-resistant weeds, but dicamba is expected to displace some 

herbicides that would otherwise be used, and which could have a more significant 

environmental footprint. Nonetheless, EPA has determined that when herbicides are used in 

accordance with their labels, no unreasonable adverse impacts will result. As discussed above, 

EPA’s conclusions are based on comprehensive evaluations and risk assessments. 

Glufosinate has been used over-the-top of glufosinate-tolerant crops since 1995. Glufosinate is 

currently labeled for in-crop application with glufosinate-tolerant cotton from emergence 

through early bloom growth stage. The use pattern and rate of glufosinate on DGT cotton will 

follow the existing glufosinate-tolerant cotton uses outlined on the glufosinate herbicide label.

In summary, in terms of potential impacts to animal communities, including insects, beneficial 

arthropods, and all other animals that live in or near cotton fields containing DGT cotton, the 

difference between the No Action and Deregulation in Whole Alternatives is primarily the 

difference in the types of herbicides that may be used. EPA has determined that when 

herbicides are used in accordance with their labels, no unreasonable adverse impacts will result. 

As discussed above, EPA’s conclusions are based on comprehensive evaluations and risk 

assessments. Compared to the Deregulation in Whole Alternative, the No Action Alternative 

may pose a small increase in adverse impact on animal communities if it results in increased 

tillage, because crop residue provides shelter and food for wildlife, such as game birds and small 

animals (CTIC 2011).

IV.D.1.d. Approval in Whole of DT Soybean and DGT Cotton 

As discussed in detail above, in terms of potential impacts to animal communities, including 

insects, beneficial arthropods, and all other animals that live in or near soybean and cotton 

fields containing DT soybean and DGT cotton, the difference between the No Action and 

Deregulation in Whole Alternatives is primarily the difference in the types of herbicides that 

may be used. EPA has determined that when herbicides are used in accordance with their 

labels, no unreasonable adverse impacts will result. As discussed above, EPA’s conclusions are 

based on comprehensive evaluations and risk assessments. Compared to the Deregulation in 

Whole Alternative, the No Action Alternative may pose a small increase in adverse impact on 

animal communities if it results in increased tillage, as crop residue provides shelter and food 

for wildlife, such as game birds and small animals (CTIC 2011).

IV.D.2. Plant Communities

Consistent with the Plant Communities discussion in Section II.D.1.b, this discussion considers 

both agricultural and non-agricultural plants outside the soybean and cotton fields that may

have the potential to be affected by the use of DT soybean and DGT cotton. Non-soybean 

and non-cotton plants within the field are considered weeds and are addressed in Section 
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II.B.1.d and Section II.B.2.d. Potential impacts to plant communities through gene flow and 

increased weediness characteristics are addressed in Section II.D.1.c and Section II.D.2.c.

Plants on adjacent land, including agricultural crops, have the potential to be affected by 

herbicide transported in surface water runoff and in air. A herbicide could undergo air 

transport from the intended application site either by particle drift during spray application or 

by post-application volatilization from treated surfaces if appropriate mitigation measures are 

not taken. Spray drift of herbicides is a familiar and well-studied phenomenon (Felsot et al. 

2010). Aerial application is associated with increased drift potential compared to ground spray 

application because the herbicide is released at a greater distance above the crop canopy.

IV.D.2.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially available (both GE and 

non-GE) soybean and commercially available (both GE and non-GE) cotton are expected to 

remain the same under the No Action Alternative. Under this alternative DT soybean and 

DGT cotton would not become integrated into the glyphosate-tolerant soybean or cotton 

systems and dicamba use would likely remain similar to today’s use pattern in soybean and 

cotton. 

As discussed under in Section II.D.1.c, cultivated soybean and cultivated cotton are largely selfpollinating, and no wild (native) or feral species of Glycine or Gossypium have been found in 

soybean-growing or cotton-growing areas in North America. Gene flow to sexually compatible 

plants and weediness are not concerns with existing commercial soybean and cotton, and would 

not be expected to be concerns with new varieties that may be introduced.

Currently herbicides are used on nearly all (~98%) soybean acres, and over 35 different 

herbicide active ingredients are approved for use in soybean (Section II.B.1.d). Currently 

herbicides are used on nearly all (>99%) cotton acres, and approximately 39 million pounds of 

30 different herbicides are applied pre- or postemergence in cotton production (Monsanto, 

2012) (Section II.B.2.d). The use of herbicides in soybean and cotton production is expected to 

continue to increase as more growers adopt diversified weed management strategies to combat 

hard-to-control weeds and herbicide-resistant biotypes. Adding additional herbicides with 

different modes-of-action into the soybean and cotton production systems to mitigate 

development of glyphosate-resistant weeds and control glyphosate-resistant weeds would 

continue to remain an option. Potential offsite impacts to adjacent plants from these 

alternative herbicides would vary, depending on active ingredients, weather conditions, 

formulations, application methods, and other factors.

IV.D.2.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes to plant communities. 

The difference between the No Action and the Deregulation in Whole Alternatives for DT 

soybean would be the gradual integration of the dicamba-tolerant event DT soybean with the 

current glyphosate-tolerant soybean systems using traditional breeding techniques. As gene 

flow and weediness are not currently concerns in existing commercial soybean production, no 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 228 of 946

concern would be expected under the Deregulation in Whole Alternative unless DT soybean 

has characteristics that make it more likely to cross-pollinate and introgress with cultivated 

soybean, establish feral populations in soybean-growing regions, or allow it to be commercially 

produced in areas where it is not currently grown. 

Potential Impacts from the Genetic Modification. With the exception of its tolerance to 

dicamba, DT soybean has been shown to be no different from non-GE soybean in its 

phenotypic, agronomic, and ecological characteristics including pollen diameter, viability and 

morphology (see Appendix G of this Environmental Report). Thus, DT soybean is expected 

to be no different from other soybean in its ability to cross pollinate with other soybean. In 

addition, DT soybean is not different from non-GE soybean in terms of seed dormancy and 

germination, susceptibility to or tolerance of disease or insect pests, and response to abiotic 

stressors (such as compaction, drought, high winds, nutrient deficiency, etc.), and would 

therefore be no different than non-GE soybean in its potential for volunteers and feral 

populations. In particular, the lack of hard seed, a well-accepted characteristic often associated 

with plants that are weeds, supports a conclusion of no increased weediness of DT soybean

compared to commercially cultivated soybean (see Appendix G of this Environmental Report).

Phenotypic and agronomic information collected from field trials conducted in 2008 using the 

same agricultural inputs showed no meaningful changes between DT soybean and the 

conventional control (see Appendix G of this Environmental Report). Information presented 

in the petition demonstrates that compared to other commercially cultivated soybean, DT 

soybean does not display increased susceptibility to pests or diseases, and is not changed 

regarding crop emergence, growth and development, or yield. Additional laboratory and 

greenhouse-based experiments reached the same conclusion. Therefore, there is no expectation 

that the introduction of DT soybean and its use in development of soybean varieties will alter 

the geographical range of commercial soybean cultivation. Thus, the introduction of DT 

soybean is not anticipated to facilitate production of soybean in areas where it is not currently 

grown or have a notable impact on total soybean production acres. 

Importantly, the potential environmental consequences of pollen transfer from DT soybean to 

other soybean or related Glycine species is considered to be negligible because of the safety of 

the introduced proteins and lack of any selective advantage by the dicamba trait that might be 

conferred on the recipient feral soybean or wild relatives. Furthermore, no wild (native) or feral 

species of Glycine have been found in soybean-growing areas (Section II.D.1.c).

Based on these characteristics of DT soybean, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on other plants as a result of the 

genetic modification.

Potential Impacts from Dicamba. The Deregulation in Whole Alternative would likely result 

in an increase in dicamba use compared to current levels. 

When proper mitigation measures and pesticide application techniques are utilized, offsite 

impacts to non-target vegetation as a result of offsite movement can be avoided. Such 

mitigation measures and techniques often focus on reducing potential impacts to non-target 

vegetation from offsite movement from particle (spray) and vapor (volatility). U.S. EPA 

considers possible effects from offsite movement as part of the pesticide registration process. 

In order to approve the use of a pesticide (herbicide) under FIFRA, U.S. EPA must conclude 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 229 of 946

that no unreasonable adverse effects on non-target vegetation will result from offsite 

movement when the herbicide is used according to the product label. 

A detailed discussion about offsite movement is provided in Appendix D to this 

Environmental Report. As discussed therein, experimental testing has shown that, in the 

absence of proper mitigation measures and pesticide techniques, offsite movement of dicamba 

can result in visual symptoms and/or injury to trees and certain sensitive crops, particularly 

beans (e.g., dry and snap beans), cotton, flowers, fruit trees, grapes, ornamentals, peas, potatoes, 

soybean, sunflower, tobacco, tomatoes, and other broadleaf plants when contacting their roots, 

stems or foliage (BASF Corporation 2008; Jordan, et al. 2009). These plants are most sensitive 

to dicamba during their development or growing stage (BASF Corporation 2008). 

However when herbicides are applied according to the FIFRA label application instructions, 

offsite impacts can be avoided. EPA concluded in the dicamba RED (U.S. EPA 2009a) that 

existing FIFRA label language to mitigate offsite movement was sufficient to reduce the 

potential risk of damage to adjacent vegetation. Because the proposed application rates for 

dicamba on DT soybean are less than or equivalent to rates for dicamba established for other 

uses in the dicamba RED, and because these uses were evaluated by EPA as part of the RED 

and the proposed label contains the offsite movement mitigation language, it is reasonable to 

conclude that the use of dicamba on DT soybean also meets the FIFRA no unreasonable 

effects standard for drift and offsite movement (U.S. EPA 2009a). Monsanto’s request for the 

use of dicamba on DT soybean only for low-volatility salts such as the DGA salt formulation 

(U.S. EPA Reg. No. 524-582) is currently pending before EPA. The proposed FIFRA label’s 

inclusion of specific application requirements, such as a no-spray buffer to protect dicambasensitive areas (see Appendix D of this Environmental Report for additional details), and/or 

any other measures imposed by EPA, will reduce dicamba offsite movement and potential 

impacts to adjacent sensitive areas. Furthermore, to further minimize potential impacts from 

post application volatilitzation, Monsanto will not allow growers to use dimethylamine salt 

(DMA) of dicamba and/or dicamba acid on DT soybean.

Growers and commercial applicators are aware of the sensitivity of certain crops to herbicides, 

including dicamba, and the extra precautions that should be taken in making applications when 

these crops are nearby. In addition, growers and commercial applicators follow label directions 

and restrictions, and growers are educated by university specialists and industry representatives 

on the proper application equipment, equipment setup, and climatic conditions to maximize 

herbicide performance and minimize offsite movement of herbicides. To provide growers with 

specific information for dicamba applications to dicamba-tolerant crops, Monsanto is 

implementing a robust stewardship program that will include a strong emphasis on grower and 

applicator training. In addition, U.S. EPA and state agencies have enforcement authority over 

the use of any registered pesticide in a manner inconsistent with its labeling.

In summary, EPA regulates the use of herbicides and has concluded that dicamba offsite 

movement from labeled uses similar to those proposed on DT soybean do not pose 

unreasonable adverse effects to non-target vegetation. Furthermore, as indicated above, when 

herbicides are applied in accordance with the FIFRA label application use instructions, which 

are legally enforceable, impacts on adjacent agricultural crops and non-agricultural plants can be 

avoided. Monsanto has submitted a proposed label to EPA for the use of dicamba on DT

soybean, and EPA must approve the product label before any applications can be made. Thus, 

potential impacts to these adjacent areas due to deregulation of DT soybean and use of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 230 of 946

dicamba are similar when compared to the No Action Alternative. Therefore, the Deregulation 

in Whole and No Action Alternatives are similar regarding potential impacts on adjacent 

agricultural and non-agricultural areas.

IV.D.2.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to plant communities. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. As gene flow 

and weediness are not currently concerns in existing commercial cotton production, no concern 

would be expected under the Deregulation in Whole Alternative unless DGT cotton has 

characteristics that make it more likely to cross-pollinate and introgress with cultivated cotton, 

establish feral populations in cotton-growing regions, or allow it to be commercially produced 

in areas where it is not currently grown. 

Potential Impacts from the Genetic Modification. With the exception of its tolerances to 

both dicamba and glufosinate, DGT cotton has been shown to be no different from non-GE 

cotton in its phenotypic, agronomic, and ecological characteristics including pollen diameter, 

viability and morphology (see Appendix G of this Environmental Report). Thus, DGT cotton 

is expected to be no different from other cotton in its ability to cross pollinate with other 

cotton. In addition, DGT cotton is not different from non-GE cotton in terms of seed 

dormancy and germination, susceptibility to or tolerance of disease or insect pests, and 

response to abiotic stressors (such as compaction, drought, high winds, nutrient deficiency, 

etc.), and would therefore be no different than non-GE cotton in its potential for volunteers 

and feral populations. In particular, the lack of hard seed, a well-accepted characteristic often 

associated with plants that are weeds, supports a conclusion of no increased weediness of DGT 

cotton compared to commercially cultivated cotton (see Appendix G of this Environmental 

Report).

Phenotypic and agronomic information collected from field trials conducted in 2010 using the 

same agricultural inputs showed no meaningful changes between DGT cotton and the 

conventional control (see Appendix G of this Environmental Report). Information presented 

in the petition demonstrates that compared to other commercially cultivated cotton, DGT 

cotton does not display increased susceptibility to pests or diseases, and is not changed 

regarding crop emergence, growth and development, or yield. Additional laboratory and 

greenhouse-based experiments reached the same conclusion. Therefore, there is no expectation 

that the introduction of DGT cotton and its use in development of cotton varieties will alter 

the geographical range of commercial cotton cultivation. Thus, the introduction of DGT 

cotton is not anticipated to facilitate production of cotton in areas where it is not currently 

grown or have a notable impact on total cotton production acres. 

Importantly, the potential environmental consequences of pollen transfer from DGT cotton to 

other cotton or related Gossypium species is considered to be negligible because of the safety of 

the introduced proteins and lack of any selective advantage by the dicamba and glufosinate 

traits that might be conferred on the recipient feral cotton or wild relatives. Furthermore, no 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 231 of 946

wild (native) or feral species of Gossypium have been found in cotton-growing areas (Fryxell 

1984; Waghmare et al. 2005).

Based on these characteristics of DGT cotton, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on other plants as a result of the 

genetic modification.

Potential Impacts from Dicamba. The Deregulation in Whole Alternative would likely result 

in an increase in dicamba use in cotton compared to its current use. This discussion focuses 

on dicamba, as no changes to allowable glufosinate use on cotton are expected.

As discussed in Approval in Whole of DT Soybean, but not DGT Cotton, when herbicides are applied 

according to the FIFRA label application instructions, offsite impacts can be avoided. The 

proposed application rates for dicamba on DGT cotton are less than or equivalent to rates for 

dicamba established for other uses in the dicamba RED, and because these uses were evaluated 

by EPA as part of the RED and the proposed label contains the offsite movement mitigation 

language, discussed above, it is reasonable to conclude that the use of dicamba on DGT cotton 

also meets the FIFRA no unreasonable effects standard for drift and offsite movement (U.S. 

EPA 2009a; d). Monsanto’s request for the use of dicamba on DGT cotton only for lowvolatility salts such as the DGA salt formulation (U.S. EPA Reg. No. 524-582) is currently 

pending before EPA. The proposed FIFRA label’s inclusion of specific application 

requirements, such as a no-spray buffer to protect dicamba-sensitive areas (see Appendix D of 

this Environmental Report for additional details), and/or any other measures imposed by EPA, 

will reduce dicamba offsite movement and potential impacts to adjacent sensitive areas. 

Furthermore, to further minimize potential impacts from post application volatilitzation, 

Monsanto will not allow growers to use dimethylamine salt (DMA) of dicamba and/or dicamba 

acid on DGT cotton.

In summary, EPA regulates the use of herbicides and has concluded that dicamba offsite 

movement from labeled uses similar to those proposed on DGT cotton do not pose 

unreasonable adverse effects to non-target vegetation. Furthermore, as indicated above, when 

herbicides are applied in accordance with the FIFRA label application use instructions, which 

are legally enforceable, impacts on adjacent agricultural crops and non-agricultural plants can be 

avoided. Monsanto has submitted a proposed label to EPA for the use of dicamba on DGT

cotton, EPA must approve the product label before any applications can be made. Thus, 

potential impacts to these adjacent areas due to deregulation of DGT cotton and use of 

dicamba are similar when compared to the No Action Alternative. Therefore, the Deregulation 

in Whole and No Action Alternatives are similar regarding potential impacts on adjacent 

agricultural and non-agricultural areas.

IV.D.2.d. Approval in Whole of DT Soybean and DGT Cotton 

As discussed in detail above, in terms of potential impacts to plant communities, the difference 

between the No Action and the Deregulation in Whole Alternatives would be the gradual 

integration of the dicamba and glufosinate-tolerant event DT soybean and DGT cotton with 

the current glyphosate-tolerant soybean and cotton systems using traditional breeding 

techniques. Gene flow and weediness are not concerns in existing commercial soybean and 

cotton production. EPA regulates the use of herbicides and has concluded that dicamba offsite 

movement from labeled uses do not pose unreasonable adverse effects to non-target 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 232 of 946

vegetation. Furthermore, as indicated above, when herbicides are applied in accordance with 

the FIFRA label application use instructions, which are legally enforceable, impacts on adjacent 

agricultural crops and non-agricultural plants can be avoided. Thus, potential impacts to these 

adjacent areas due to deregulation of DT soybean and use of dicamba are similar when 

compared to the No Action Alternative. Therefore, the Deregulation in Whole and No Action 

Alternatives are similar regarding potential impacts on adjacent agricultural and non-agricultural 

areas.

IV.D.3. Gene Flow and Weediness

IV.D.3.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT Cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially available (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. Under this alternative DT soybean and DGT cotton would not become integrated 

into the glyphosate-tolerant soybean and cotton systems and dicamba use would likely remain 

similar to today’s use pattern in soybean and cotton. 

As discussed below in Section V.J, cultivated soybean and cotton are largely self-pollinating, 

and no wild (native) or feral species of Glycine or wild (native) or feral species of Gossypium have 

been found in soybean-growing or cotton-growing regions of the U.S. Gene flow to sexually 

compatible plants and weediness are not concerns with existing commercial soybeans or with 

existing commercial cotton, and would not be expected to be concerns with new varieties that 

may be introduced.

IV.D.3.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, No Action Alternatives for DGT cotton is not expected to result in 

significant changes to animal communities. 

With the exception of its tolerance to dicamba, DT soybean has been shown to be no different 

from non-GE soybean in its phenotypic, agronomic, and ecological characteristics including 

pollen diameter, viability and morphology (see Appendix G of this Environmental Report). 

Thus, DT soybean is expected to be no different from other soybean in its ability to cross 

pollinate with other soybean. In addition, DT soybean is not different from non-GE soybean 

in terms of seed dormancy and germination, susceptibility to or tolerance of disease or insect 

pests, and response to abiotic stressors (such as compaction, drought, high winds, nutrient 

deficiency, etc.), and would therefore be no different than non-GE soybean in its potential for 

volunteers and feral populations. In particular, the lack of hard seed, a well-accepted 

characteristic often associated with plants that are weeds, supports a conclusion of no increased 

weediness of DT soybean compared to commercially cultivated soybean (see Appendix G of 

this Environmental Report).

Phenotypic and agronomic information collected from field trials conducted in 2008 using the 

same agricultural inputs showed no meaningful changes between DT soybean and the 

conventional control (see Appendix G of this Environmental Report). Information presented 

in the petition demonstrates that compared to other commercially cultivated soybean, DT 

soybean does not display increased susceptibility to pests or diseases, and is not changed 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 233 of 946

regarding crop emergence, growth and development, or yield. Additional laboratory and 

greenhouse-based experiments reached the same conclusion. Therefore, there is no expectation 

that the introduction of DT soybean and its use in development of soybean varieties will alter 

the geographical range of commercial soybean cultivation. Thus, the introduction of DT 

soybean is not anticipated to facilitate production of soybean in areas where it is not currently 

grown or have a notable impact on total soybean production acres. 

Importantly, the potential environmental consequences of pollen transfer from DT soybean to

other soybean or related Glycine species is considered to be negligible because of the safety of 

the introduced proteins and lack of any selective advantage by the dicamba trait that might be 

conferred on the recipient feral soybean or wild relatives. Furthermore, no wild (native) or feral 

species of Glycine have been found in soybean-growing areas Section II.D.1.c.

Based on these characteristics of DT soybean, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on other plants as a result of the gene 

flow or weediness.

IV.D.3.c. Approval in Whole of DGT Cotton, but not DT Soybean

With the exception of its tolerances to both dicamba and glufosinate, DGT cotton has been 

shown to be no different from non-GE cotton in its phenotypic, agronomic, and ecological 

characteristics including pollen diameter, viability and morphology (see Appendix G of this 

Environmental Report for details). Thus, DGT cotton is expected to be no different from 

other cotton in its ability to cross pollinate with other cotton. In addition, DGT cotton is not 

different from non-GE cotton in terms of seed dormancy and germination, susceptibility to or 

tolerance of disease or insect pests, and response to abiotic stressors (such as compaction, 

drought, high winds, nutrient deficiency, etc.), and would therefore be no different than nonGE cotton in its potential for volunteers and feral populations. In particular, the lack of hard 

seed, a well-accepted characteristic often associated with plants that are weeds, supports a 

conclusion of no increased weediness of DGT cotton compared to commercially cultivated 

cotton (see Appendix G of this Environmental Report).

Phenotypic and agronomic information collected from field trials conducted in 2010 using the 

same agricultural inputs showed no meaningful changes between DGT cotton and the 

conventional control (see Appendix G of this Environmental Report). Information presented 

in the petition demonstrates that compared to other commercially cultivated cotton, DGT 

cotton does not display increased susceptibility to pests or diseases, and is not changed 

regarding crop emergence, growth and development, or yield. Additional laboratory and 

greenhouse-based experiments reached the same conclusion. Therefore, there is no expectation 

that the introduction of DGT cotton and its use in development of cotton varieties will alter 

the geographical range of commercial cotton cultivation. Thus, the introduction of DGT 

cotton is not anticipated to facilitate production of cotton in areas where it is not currently 

grown or have a notable impact on total cotton production acres. 

Importantly, the potential environmental consequences of pollen transfer from DGT cotton to 

other cotton or related Gossypium species is considered to be negligible because of the safety 

of the introduced proteins and lack of any selective advantage by the dicamba and glufosinate 

traits that might be conferred on the recipient feral cotton or wild relatives. Furthermore, no 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 234 of 946

wild (native) or feral species of Gossypium have been found in cotton-growing areas (Fryxell 

1984; Waghmare et al. 2005). Additional details are provided in Section IV.D.2.c.

Based on these characteristics of DGT cotton, the Deregulation in Whole and No Action 

Alternatives are the same regarding their potential impact on gene flow and weediness.

IV.D.3.d. Approval in Whole of DT Soybean and DGT Cotton 

As discussed in detail above, in terms of potential impacts to gene flow and weediness, there is 

no substantial difference between the No Action and Deregulation in Whole Alternatives for 

DT soybean and DGT cotton. EPA has determined that when herbicides are used in 

accordance with their labels, no unreasonable adverse impacts will result. As discussed above, 

EPA’s conclusions are based on comprehensive evaluations and risk assessments. Further 

discussion of the difference in the types of herbicides used and associated impacts is included in 

Appendix A. Therefore, the Deregulation in Whole and the No Action Alternatives are similar 

regarding potential impacts on gene flow and weediness.

IV.D.4. Microorganisms

IV.D.4.a. No Action Alternative for Both DT Soybean and DGT Cotton 

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially available (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. Under this alternative DT soybean and DGT cotton would not become integrated 

into the glyphosate-tolerant soybean and cotton systems and dicamba use would likely remain 

similar to today’s use pattern in soybean and cotton. 

Adding other herbicides with different modes-of-action into the glyphosate-tolerant systems to

mitigate development of glyphosate-resistant weeds and control glyphosate-resistant weeds 

would continue to remain an option. Additionally, conventional tillage may increase in some 

instances as an additional means to control problematic weeds. 

Agricultural practices such as pesticide applications and tillage are known to impact soil 

microbial populations, species composition, colonization, and associated biochemical processes. 

However, alternative herbicides are already available and are used in soybean and cotton, and 

would likely be used instead of dicamba under the No Action Alternative. 

IV.D.4.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, No Action Alternatives for DGT cotton is not expected to result in 

significant changes to soil microorganisms.

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba -tolerant event DT soybean with the current glyphosatetolerant soybean systems using traditional breeding techniques. As discussed in Section 

II.B.1.c, DT soybean is not expected to alter the current agronomic practices for soybean

cultivation. No adverse effects on soil microorganisms, including agronomically important 

rhizosphere-inhabiting soil bacteria such as Bradyrhizobiaceae japonicum, are associated with DT 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 235 of 946

soybean or its cultivation, nor do the characteristics of the MON 87708 DMO protein pose any 

concern to soil microorganisms.

The use of dicamba for agricultural purposes was first established in 1967, and with the 

reregistration in 2006, EPA recently reaffirmed its conclusion that use of dicamba does not 

result in unreasonable adverse effects when applied according to label directions, including for 

soybean production (U.S. EPA 2009a). Impacts on soil microorganisms have not been raised 

as an important concern, and results of standardized tests with dicamba and dicamba 

formulations did not indicate any long term effects on soil microorganisms (Durkin and Bosch 

2004). Results of standardized tests with dicamba and dicamba formulations indicate no longterm effects on functional processes of soil microorganisms (carbon respiration and nitrogen 

transformation) at rates proposed for dicamba on DT soybean. 

On the basis of these observations and in conjunction with related phenotypic measurements 

for DT soybean, no impact on soil microorganisms is expected from the cultivation of DT 

soybean. Therefore, the Deregulation in Whole and No Action Alternatives are similar 

regarding potential impacts on soil microorganisms.

IV.D.4.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, No Action Alternatives for DT soybean is not expected to result in 

significant changes to soil microorganisms.

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. As discussed 

in Section IV.B.2.c, DGT cotton is not expected to alter the current agronomic practices for 

cotton cultivation. No adverse effects on soil microorganisms are associated with DGT cotton 

or its cultivation, nor do the characteristics of the MON 88701 DMO or PAT (bar) pose any 

concern to soil microorganisms.

The use of dicamba for agricultural purposes was first established in 1967, and with the 

reregistration in 2006, EPA recently reaffirmed its conclusion that use of dicamba does not 

result in unreasonable adverse effects when applied according to label directions, including for 

cotton production (U.S. EPA 2009a). Impacts on soil microorganisms have not been raised as 

an important concern, and results of standardized tests with dicamba and dicamba formulations 

did not indicate any long term effects on soil microorganisms (Durkin and Bosch 2004). 

Results of standardized tests with dicamba and dicamba formulations indicate no long-term 

effects on functional processes of soil microorganisms (carbon respiration and nitrogen 

transformation) at rates proposed for dicamba on DGT cotton (EFSA 2007c). Glufosinate is 

currently used on cotton at the rates that would be the same as those used on DGT cotton.

On the basis of these observations and in conjunction with related phenotypic measurements 

for DGT cotton, no impact on soil microorganisms is expected from the cultivation of DGT 

cotton. Therefore, the Deregulation in Whole and No Action Alternatives are similar regarding 

potential impacts on soil microorganisms. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 236 of 946

IV.D.4.d. Approval in Whole of DT Soybean and DGT Cotton

As discussed in detail above, in terms of potential impacts to soil microorganisms in or near 

soybean and cotton fields containing DT soybean or DGT cotton, the there is no substantial 

difference between the No Action and Deregulation in Whole Alternatives for potential 

impacts on soil microorganisms. No adverse effects on soil microorganisms are associated with 

DT soybean or its cultivation, nor do the characteristics of the MON 87708 DMO protein pose 

any concern to soil microorganisms. No adverse effects on soil microorganisms are associated 

with DGT cotton or its cultivation, nor do the characteristics of the MON 88701 DMO or 

PAT (bar) pose any concern to soil microorganisms. Therefore, the Deregulation in Whole of 

DT soybean and DGT cotton and No Action Alternatives are the same regarding their 

potential impact on soil microorganisms. 

IV.D.5. Bioiversity

IV.D.5.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, DT soybean and DGT Cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially available (both GE and 

non-GE) soybean and cotton are expected to remain the same under the No Action 

Alternative. Under this alternative DT soybean and DGT cotton would not become integrated 

into the glyphosate-tolerant soybean and cotton systems and dicamba use would likely remain 

similar to today’s use pattern in soybean and cotton. As discussed in Sections III.D.1.e and 

III.D.2.e, the use of herbicides in agricultural fields impacts biodiversity within the field by 

decreasing weed species. It is the grower’s goal, for his economic well-being, to cultivate a 

single plant species in the field, to the exclusion of other species. 

Currently 98% of soybean fields are treated with herbicides and 99% of cotton fields are treated 

with herbicides, averaging four applications per year. Soybean fields and cotton fields would be 

expected to continue to have low plant diversity, and associated low animal diversity.

IV.D.5.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to result in 

significant changes to plant or animal biodiversity. 

For DT soybean, the difference between the No Action and the Deregulation in Whole 

Alternatives would be the gradual integration of the dicamba -tolerant event DT soybean with

the current glyphosate-tolerant soybean systems using traditional breeding techniques. Except 

for tolerances to dicamba, DT soybean is phenotypically and agronomically the same as its nonGE counterpart (Appendix G of this Environmental Report). Therefore, DT soybean would

not be expected to have direct impacts on biodiversity any different than other commercially 

available soybean. 

U.S. soybean fields currently have low plant (and associated animal) diversity by intent and 98% 

of soybean fields are treated with herbicides. Therefore, introduction of DT soybean and 

treatment with dicamba and is unlikely to affect the animal or plant communities found in 

soybean fields differently than today’s practices. Based on this analysis, it is concluded that the 

potential effect of Deregulation in Whole of DT soybean on biodiversity would not differ from 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 237 of 946

impacts associated with current agricultural practices used for production of soybean. 

Therefore, the Deregulation in Whole and the No Action Alternatives are similar regarding 

potential impacts on biodiversity.

IV.D.5.c. Approval in Whole of DGT Cotton, but not DT Soybean 

As discussed above, the No Action Alternative for DT soybean is not expected to result in 

significant changes to plant or animal biodiversity. 

With respect to DGT cotton, the difference between the No Action and the Deregulation in 

Whole Alternatives would be the gradual integration of the dicamba and glufosinate-tolerant 

event DGT cotton with the current glyphosate-tolerant cotton systems using traditional 

breeding techniques. Except for tolerances to both dicamba and glufosinate, DGT cotton is 

phenotypically and agronomically the same as its non-GE counterpart (Appendix G to this 

Environmental Report). Therefore, DGT cotton would not be expected to have direct impacts

on biodiversity any different than other commercially available cotton. 

U.S. cotton fields currently have low plant (and associated animal) diversity by intent and over 

99% of cotton fields are treated with herbicides, averaging four applications per year. 

Therefore, introduction of DGT cotton and treatment with dicamba and or glufosinate is 

unlikely to affect the animal or plant communities found in cotton fields differently than today’s 

practices. Based on this analysis, it is concluded that the potential effect of Deregulation in 

Whole of DGT cotton on biodiversity would not differ from impacts associated with current 

agricultural practices used for production of cotton. Therefore, the Deregulation in Whole and 

the No Action Alternatives are similar regarding potential impacts on biodiversity.

IV.D.5.d. Approval in Whole of DT Soybean and DGT Cotton

As discussed in detail above, in terms of potential impacts to plant and animal diversity in or 

near soybean and cotton fields containing DT soybean or DGT cotton, there is no substantial 

difference between the No Action and Deregulation in Whole Alternatives for potential 

impacts on plant and animal diversity. U.S. soybean and cotton fields currently have low plant 

(and associated animal) diversity by intent and 98% of soybean fields are treated with herbicides 

and 99% of cotton fields are treated with herbicides, averaging four applications per year. 

Therefore, the Deregulation in Whole and the No Action Alternatives are similar regarding 

potential impacts on biodiversity.

IV.E. HUMAN HEALTH AND SAFETY IMPACTS

IV.E.1. Human Health

IV.E.1.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially cultivated (both GE and 

non-GE) soybeans and cotton would be expected to remain the same under the No Action 

Alternative. Thus, exposure to DT soybean and DGT cotton would also remain unchanged. 

Consumer exposure to existing conventional and GE soybeans and cotton would remain 

unchanged, with continued exposure to currently used herbicides in soybeans and cotton. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 238 of 946

IV.E.1.b. Approval of DT Soybean, but not DGT Cotton

As discussed above, approval of the No Action Alternative for DGT cotton is not expected to 

have significant impacts on human health.

Under full deregulation, DT soybean could be grown broadly across the U.S. Soybean and 

forage produced from DT soybean would enter the food and feed chain and would be 

consumed by humans and animals. Agricultural workers would be exposed to DT soybean and 

its associated agricultural practices. Monsanto has completed the U.S. FDA consultation 

process for DT soybean, with FDA confirming the safety of DT soybean-derived food and 

feed on October 11, 2011. 

The potential human health impacts associated with the introduction of DT soybean and 

increased applications of dicamba are separately discussed below. As discussed elsewhere in 

this report, however, Congress transferred regulatory authority over herbicides from USDA to 

EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or herbicide resistance, 

and no authority to consider herbicide impacts under the PPA. Nonetheless, because APHIS 

indicated in its Notice of Intent to Prepare an Environmental Impact Statement (78 Fed. Reg. 

28796, May 16, 2013) that it would be considering herbicide effects and herbicide resistance as 

part of the NEPA process, Monsanto has included a discussion of herbicide impacts in the 

following section. Importantly, however, Monsanto believes that APHIS has no legal 

obligation under NEPA to consider herbicide impacts or herbicide resistance in any 

Environmental Impact Statement or Environmental Assessment. See DOT v. Public Citizen, 

541 U.S. 752, 770, 769 (2004) (where an agency has no ability to prevent a certain effect due to 

its limited statutory authority over the relevant actions, the agency cannot be considered a 

legally relevant “cause” of the effect, and is therefore not required to analyze the environmental 

impact of an action it could not refuse to perform). See also Center for Food Safety v. Vilsack, 

No. 12-15052, 2013 U.S. App. LEXIS 9920, at *16-17 (9th Cir. 2013) (“If APHIS concludes 

that the presumptive plant pest does not exhibit any risk of plant pest harm, APHIS must 

deregulate it since the agency does not have jurisdiction to regulate organisms that are not plant 

pests.”).

DT Soybean: DT soybean was developed through Agrobacterium-mediated transformation of 

soybean meristem tissue using the binary transformation plasmid PV-GMHT4355. DT 

soybean contains one copy of the insert at a single integration locus. No additional genetic 

elements from the transformation vector were detected in the genome of DT soybean, 

including backbone sequence from plasmid PV-GMHT4355. Additionally, the data confirm 

the organization and sequence of the insert, and demonstrate the stability of the insert over 

several generations. On the basis of these data, it is concluded that only the MON 87708

DMO is produced from the inserted DNA. 

For DT soybean, the available data demonstrate that harvested seed is as safe as conventional 

soybean for food and feed uses; thus it is safe and wholesome for consumption. To assess the 

impact of the DMO protein in DT soybean on food and feed safety, bioinformatic analyses 

were used to establish the lack of both structurally and immunologically-relevant similarities 

between DT soybean and allergens or toxins, based on the amino acid sequence of 

MON 87708 DMO. Furthermore, digestive fate experiments conducted with MON 87707 

DMO demonstrate rapid digestion in simulated gastric fluid (SGF), a characteristic shared 

among many proteins with a history of safe consumption. Rapid digestion of MON 87708 in
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SGF indicates that it is highly unlikely that DT soybean DMO will reach absorptive cells of the 

intestinal mucosa. This, combined with the history of safe consumption of mono oxygenases 

(the class of enzymes to MON 87708 DMO belongs) and the lack of homology of the amino 

acid sequence to known allergens and toxins, supports a conclusion that MON 87708 DMO 

has low allergenic and toxic potential. Finally, a high dose of MON 87708 DMO in a mouse 

acute oral toxicity evaluation demonstrated that it is not acutely toxic, and does not cause any 

adverse effect. The safety assessment supports the conclusion that exposure to MON 87708 

DMO poses no meaningful risk to human or animal health. 

Extensive analysis of the composition of DT soybean seed and forage demonstrated that no 

biologically relevant changes were detectable. A detailed compositional assessment of soybean 

harvested seed and forage is presented in the DT Soybean Petition and Appendix G of this 

Environmental Report. The levels of key nutrients, anti-nutrients, and other components in 

DT soybean were examined and compared to that of the near-isogenic conventional soybean 

control, A3525, a conventional soybean variety with background genetics representative of DT 

soybean, but without the genetic modification. Additionally, tolerance intervals representing

99% of the values of each analyte for a commercial soybean population were established. 

Results demonstrate that the levels of key nutrients, anti-nutrients, and other components of 

DT soybean are compositionally equivalent to the conventional control and within the range of 

variability of commercial soybean that were grown concurrently in the same trial. Furthermore, 

FDA completed its consultation on the food, feed and nutritional safety assessment on DT 

soybean on October 11, 2011, confirming Monsanto’s conclusion on the safety of DT soybean 

derived food and feed.

On the basis of the characteristics of MON 88701 DMO and the extensive compositional 

characterization of DT soybean harvested seed, no impacts to human health are expected from 

the Deregulation in Whole Alternative. 

Dicamba: The toxicology or risk profile of dicamba has been extensively reviewed (U.S. EPA 

2009a; d). Dicamba does not pose any unusual toxicological concerns and is not carcinogenic 

(Durkin and Bosch 2004; European Commission 2007; U.S. EPA 2009d). EPA completed the 

reregistration of dicamba in 2006. The Reregistration Eligibility Decision (RED) document for 

dicamba and its associated salts concluded that a high level of confidence exists for the dicamba 

hazard data base and the reliability of these data necessary to support the required finding for 

continued registration, including the pre-harvest use on commercial soybean. The dicamba 

RED document, and the related EPA Health Effects Division (HED) chapter (U.S. EPA 

2005d), provide a detailed overview of the toxicological properties of dicamba. Dicamba’s 

toxicity profile is presented in Appendix L of the DT Soybean Petition, and summarized in 

Appendices A and E of this Environmental Report. 

EPA evaluated the potential risks to humans from the use of dicamba as a part of the dicamba 

RED, concluding that aggregate exposure to dicamba, defined as dietary (food and water) and 

non-occupational (residential and recreational) exposures, meet the FIFRA determination of no 

unreasonable adverse effects and the FFDCA determination for reasonable certainty of no 

harm to human health. EPA has conducted acute and chronic dietary (food and water) risk 

assessments for dicamba based on a theoretical worst case exposure estimate. For food, this 

estimate assumes that dicamba is used on 100 percent of all the crops on which the pesticide is 

currently approved for use. It further assumes that the resulting pesticide residues found on all 

harvested food and feed crops and derived animal food commodities (e.g., meat and milk) are 
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at the level of the legally established tolerance (i.e., the maximum allowable pesticide residue 

level). Residues of dicamba are defined as dicamba and its metabolites 5-hydroxy dicamba and 

3,6-dichlorosalicylic acid (DCSA) in soybean commodities, and as dicamba and DCSA in 

animal food commodities, as currently regulated in 40 CFR § 180.227. For water, EPA 

assumed that dicamba could potentially move offsite to adjacent surface water bodies as a result 

of drift or runoff, or move through soil to groundwater. Since the estimated concentrations in 

groundwater were significantly lower compared to surface water, surface water estimates were 

used in the worst case dietary assessments. Surface water estimates were generated with the 

conservative screening level models SCIGROW and PRZM/EXAM using an exaggerated 

application rate that is 2.8 times higher than the current 1.0 lb a.e./A maximum single 

application rate established in the dicamba RED (U.S. EPA 2005a; d; c; 2009d), and the 

maximum single application rate proposed for DT soybean . EPA mandated reductions in 

dicamba use rates as part of the dicamba RED (1 lb a.e./A and 2 lb a.e./A for a single 

application and for annual application, respectively) (See Appendices A and C of this 

Environmental Report for more detail on dicamba levels in water resources). 

Based on the worst-case assumptions outlined above and in Appendix H, acute and chronic 

dietary exposure was well below the Agency’s level of concern to satisfy the FIFRA and 

FFDCA standards (U.S. EPA 2009d).

Characterization of the nature of dicamba residues in DT soybean confirms no additional 

residues of concern are created in DT soybean, and the current soybean seed dicamba residue 

definition is applicable for DT soybean. Residue levels in soybean seed harvested from DT 

soybean treated with dicamba at the proposed maximum allowable application use pattern (1.0 

pound a.e. per acre preemergence and two 0.5 pound a.e. per acre postemergence applications) 

were less than 0.1 ppm, well below the established 10 ppm tolerance supporting the current use 

of dicamba on conventional soybean. These dicamba residue data for DT soybean were 

submitted to the U.S. EPA on April 28, 2010 (OPP Decision Number: D-432753, Registration 

Number 524-582), along with a proposed label for the use of dicamba on DT soybean. 

Presently, dicamba is applied to less than 1% of soybean acres using pre-plant and pre-harvest 

burndown applications (see Appendix A to this Environmental Report). Under the 

Deregulation in Whole Alternative, dicamba will be used on more soybean acres and a higher 

percentage of soybean and soybean-derived foods will contain dicamba residues; however, 

dicamba residue levels in DT soybean harvested seed or processed foods will be significantly 

lower compared to levels originating from the current pre-harvest soybean use (approximately 

100-fold lower, based on <0.1 ppm. residue in DT soybean seed compared to established 10 

ppm tolerance (see Section II.E.1.c). It is difficult to determine the exact impact on actual 

dietary exposure from the expanded use of dicamba on DT soybean; however, the EPA 

concluded that residues of dicamba up to 10 ppm in soybean seed are safe (reasonable certainty 

of no harm as defined by FFDCA) for human and animal consumption, based on the EPA’s 

Tier 1 dietary and aggregate (dietary plus other non-occupational) exposure assessments which 

assume 100% of soybean foods contain dicamba residues at the 10 ppm tolerance level. 

Additionally, Monsanto has petitioned the EPA to establish new feed tolerances for soybean 

forage and hay to allow DT soybean forage and hay to be fed to livestock, a practice that is 

presently prohibited for dicamba-treated commercial soybean. This practice is presently not 

allowed because the current preharvest application is made past the stage where the crop would 

be useful as forage or hay. Thus, there has been no reason for pursuing these tolerances until 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 241 of 946

earlier in-crop applications of dicamba were possible, as with DT soybean. Dietary exposure to 

livestock from the feeding of DT soybean forage and hay does not result in an exceedance of 

the livestock maximum theoretical dietary burden established by the EPA, which is used to 

establish animal by-product commodity tolerances (e.g., meat and milk). Therefore, the 

approval of soybean forage and hay tolerances does not result in a change to the current animal 

by-product commodity (food) tolerances and as a result does not increase potential dietary 

exposure of dicamba. 

Since no changes to the current dicamba food tolerances (soybean seed and animal byproducts) are needed, the dietary and aggregate risk assessments conducted in the RED are 

inclusive of the incremental exposure resulting from the use of dicamba on DT soybean. 

Therefore, the deregulation of DT soybean would not present a significant impact to human 

health, and the Deregulation in Whole and No Action Alternatives are the similar regarding 

potential impacts on human health. 

IV.E.1.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, approval of the No Action Alternative for DT soybean is not expected to 

have significant impacts on human health.

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba and glufosinate-tolerant event DGT cotton with the 

current glyphosate-tolerant cotton systems using traditional breeding techniques. Prior to the 

introduction of a GE-derived crop product to the marketplace, Monsanto conducts tests to 

assure that the product is as safe as its conventional counterpart under the intended use 

conditions. GE-derived crops for food and feed use undergo a voluntary consultation process 

with the U.S. FDA prior to release into the market. Monsanto has completed the U.S. FDA 

consultation process for DGT cotton, with FDA confirming on April 24, 2013 the safety of 

food and feed derived from DGT cotton. 

DGT Cotton: Under the Deregulation in Whole Alternative, consumers could be exposed to 

food products derived from DGT cotton. As discussed in the DGT Cotton Petition and 

Appendices H and I to this Environmental Report, the only human food currently produced 

from cottonseed is refined, bleached, and deodorized (RBD) oil, and to a smaller extent, linters. 

RBD oil and linters are processed fractions that contain negligible amounts of total protein and 

the DGT cotton DMO and PAT (bar) proteins represents a very small portion of the total 

protein in the cottonseed of DGT cotton; therefore no exposure to MON 88701 DMO or 

PAT (bar) proteins is anticipated for food uses of DGT cotton.

Assessment of DGT cotton included a molecular assessment of the genetic insert to verify that 

only the intended genetic changes occurred and that the insert is stable, an assessment of the 

safety of the inserted proteins, and a compositional analysis to assess the comparability of DGT 

cotton with existing commercial counterparts. The summaries below are from the petition and 

the food and feed safety and nutritional assessment of DGT cotton that Monsanto submitted 

to FDA in April 2012, petition BNF 135.

DGT cotton was developed through Agrobacterium-mediated transformation of cotton tissue. 

Agrobacterium is a soil microbe with the ability to transfer part of its DNA into a host plant. The 

Agrobacterium transformation system has been utilized in the development of a large number of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 242 of 946

genetically engineered plants in commercial production (IOM-NRC 2004). Molecular analyses 

demonstrated that DGT cotton contains one copy of the inserted transferred DNA at a single 

integration locus. No backbone sequences from the plasmid vector were detected in the 

genome of DGT cotton. Additionally, the data confirmed the organization and sequence of the 

insert and demonstrated the stability of the insert over several generations. These data 

demonstrated that there are no unintended changes in the DGT cotton genome as a result of 

the insertion of transferred DNA encoding the MON 88701 DMO and PAT (bar) proteins. 

On the basis of these data, it is concluded that only the MON 88701 DMO and PAT (bar) are 

produced from the inserted DNA. A description of the genetic modification is included in 

Appendix G of this Environmental Report.

Monsanto has provided the FDA with information on the identity, function, and 

characterization of the genes, including expression of the gene products MON 88701 DMO 

and PAT (bar). The submittal to the FDA included information on the safety of the 

MON 88701 DMO and PAT (bar) proteins, as well as the safety of DGT cotton, including a 

dietary risk assessment. Monsanto initiated the consultation process with FDA for the 

commercial distribution of DGT cotton and submitted a safety and nutritional assessment of 

food and feed derived from DGT cotton to the FDA in April 2012. FDA completed the 

consultation process for DGT cotton on April 24, 2013. 

The safety of PAT proteins present in commercial GE-derived crops has been extensively 

assessed and in 1997 a tolerance exemption was issued for PAT proteins by U.S. EPA. 

Numerous glufosinate-tolerant products, including those in cotton, corn, soy, canola, sugarbeet, 

and rice, have been reviewed by the FDA with no concerns identified. MON 88701 DMO and 

PAT (bar) were fully characterized and the enzymatic activity of MON 88701 DMO was found 

to be specific for dicamba when tested using structurally similar cotton endogenous substrates 

(see Appendix G of this Environmental Report). The specificity of PAT proteins has been 

extensively documented in the literature. Neither protein has relevant amino acid sequence 

similarities to known allergens, toxins or other proteins that may have adverse effects on 

mammals. MON 88701 DMO and PAT (bar) were each rapidly digested in simulated gastric 

and intestinal fluids, a characteristic shared among many proteins with a history of safe 

consumption. Rapid digestion of MON 88701 DMO and PAT (bar) in simulated gastric and 

intestinal fluids indicates that it is highly unlikely that MON 88701 DMO or PAT (bar) would 

reach absorptive cells of the intestinal mucosa. Neither MON 88701 DMO nor PAT (bar) 

caused any observable adverse effects when tested in mouse acute oral toxicity analyses. In 

addition, the only fractions derived from cottonseed that are used in food applications are oil 

and linters, which contain undetectable and negligible amounts of protein, respectively. 

Therefore, MON 88701 DMO and PAT (bar) proteins comprise a very low, non-detectable 

portion of the total protein present in food derived from DGT cotton. The safety assessment 

supports the conclusion that exposure to MON 88701 DMO and PAT (bar) from DGT cotton 

poses no meaningful risk to human and animal health.

Detailed compositional analyses, in accordance with OECD guidelines, were conducted to 

assess whether levels of key nutrients and anti-nutrients in DGT cottonseed were comparable 

to levels in the conventional cotton control, Coker 130, and several commercial reference 

cotton varieties. 

Cottonseed were harvested from eight sites in which DGT cotton (treated sequentially with 

glufosinate and dicamba herbicides), the conventional control and a range of commercial 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 243 of 946

reference varieties were grown concurrently in the same field trial. The commercial reference 

varieties were used to establish a range of natural variability of the key nutrients and antinutrients in commercial cotton varieties that have a long history of safe consumption. 

Nutrients assessed in this analysis included proximates (ash, fat, moisture, protein, and 

carbohydrates by calculation), calories by calculation, acid detergent fiber, neutral detergent 

fiber, crude fiber, total dietary fiber, amino acids (18 components), fatty acids (C8-C22), 

minerals (calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, and 

zinc) and vitamin E. The key anti-nutrients assessed included gossypol and cyclopropenoid 

fatty acids (CPFA).

Based on statistical analysis of the analyzed nutrient and anti-nutrient levels, herbicide-treated 

DGT cotton is compositionally equivalent to commercially cultivated cotton and therefore the 

food and feed safety and nutritional quality of this product is comparable to that of the 

commercially cultivated cotton. These results support the overall food and feed safety of DGT 

cotton.

Based on the overall assessment of DGT cotton as related to consumer health, including the 

integrity and stability of the inserted DNA, the safety of the inserted MON 88701 DMO and 

PAT(bar) proteins, and the compositional equivalence of DGT cotton to currently available 

commercial cotton, impacts on consumer health from the Deregulation in Whole Alternative

are not expected to differ from those of the No Action Alternative.

Dicamba and Glufosinate: Under the Federal Food, Drug, and Cosmetic Act (FFDCA), 

pesticide residues in or on raw agricultural commodities or processed foods are allowed only 

after a tolerance or exemption from tolerance has been established. Residue tolerances and 

exemptions for pesticides are established by the U.S. EPA under the FFDCA. The U.S. FDA 

enforces the tolerances set by the U.S. EPA. The U.S. EPA also reviews the proposed use 

pattern for all herbicides and prior to approval and placement on herbicide labels determines 

that no unreasonable risk exists for the environment.

To support the introduction of DGT cotton, Monsanto submitted an application to EPA to 

amend Registration Number 524-582, a low-volatility DGA salt formulation, to remove all preemergence planting restrictions (application intervals, rainfall, and geographic) and to allow incrop post-emergence dicamba applications to DGT cotton. The toxicology or risk profile of 

dicamba has been extensively reviewed (U.S. EPA 2009d). Dicamba does not pose any unusual 

toxicological concerns and is not carcinogenic (Durkin and Bosch 2004; EFSA 2007a; U.S. 

EPA 2009d). EPA completed the reregistration of dicamba in 2006. The RED document for 

dicamba and its associated salts concluded a high level of confidence exists for the dicamba 

hazard data base and the reliability of these data necessary to support the required finding for 

continued registration, including the preharvest use on commercial cotton. The dicamba RED 

document, and the related EPA Health Effects Division (HED) chapter (U.S. EPA 2005a; d), 

provide a detailed overview of the toxicological properties of dicamba. A summary of 

dicamba’s toxicity profile is presented in Appendix A, Section A.4 of the DGT Cotton Petition

and Appendix E of this Environmental Report.

EPA evaluated the potential risks to humans from the use of dicamba as a part of the dicamba 

RED, concluding that aggregate exposure to dicamba, defined as dietary (food and water) and 

non-occupational (residential and recreational) exposures, meet the FIFRA determination of no 

unreasonable adverse effect (see Appendix A, Sections A.3-A.4, of the DGT Cotton Petition
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 244 of 946

and Appendix E of this Environmental Report) and the FFDCA determination for reasonable 

certainty of no harm to human health. EPA has conducted acute and chronic dietary (food and 

water) risk assessments for dicamba based on a theoretical worst case exposure estimate. For 

food, this estimate assumes that dicamba is used on 100 percent of all the crops on which the 

pesticide is currently approved for use. It further assumes that the resulting pesticide residues 

found on all harvested food and feed crops and derived animal food commodities (e.g., meat 

and milk) are at the level of the legally established tolerance (i.e., the maximum allowable 

pesticide residue level). Residues of dicamba are defined as dicamba and its metabolite 3,6-

dichloro-5-hydroxy-o-anisic acid (5-hydroxy dicamba) in cottonseed commodities, as currently 

regulated in 40 CFR § 180.227. For water, EPA assumed that dicamba could potentially move 

offsite to adjacent surface water bodies as a result of drift or runoff, or move through soil to 

groundwater. Since the estimated concentrations in groundwater were significantly lower 

compared to surface water, surface water estimates were used in the worst case dietary 

assessments. Surface water estimates were generated with the conservative screening level 

models SCIGROW and PRZM/EXAM using an exaggerated application rate that is 2.8 times 

higher than the current 1.0 lb a.e./A maximum single application rate established in the 

dicamba RED (U.S. EPA 2005d; 2009d), and the maximum single application rate proposed for 

DT soybean . EPA mandated reductions in dicamba use rates as part of the dicamba RED (1 

lb a.e./A and 2 lb a.e./A for a single application and for annual application, respectively). (See 

Appendices C and F of this Environmental Report for more detail on dicamba levels in water 

resources). 

Based on the worst-case assumptions outlined above and in Appendix H, acute and chronic 

dietary exposure was well below the Agency’s level of concern to satisfy the FIFRA and 

FFDCA standards (U.S. EPA 2009d). 

Dicamba can currently be applied to cotton in the U.S. as a preplant application, at least 21 days 

prior to planting. The tolerance of DGT cotton to dicamba facilitates a wider window of 

application on cotton, allowing preemergence application of the herbicide up to the day of crop 

emergence and post-emergence in-crop applications through seven days preharvest. Monsanto 

has requested a registration from U.S. EPA for the expanded use of dicamba on DGT cotton, 

an increase in the dicamba residue tolerance for cottonseed, the establishment of a tolerance for 

cotton gin by-products, and the inclusion of DCSA in the residue definitions for both 

cottonseed and gin by-products. No other revisions to the dicamba pesticide residue tolerances 

are necessary, including animal products such as meat and milk. Furthermore, the use of 

dicamba on DGT cotton does not present any new environmental exposure scenarios not 

previously evaluated and deemed acceptable by EPA. The potential dietary exposure to 

dicamba associated with these proposed changes in cotton tolerances are minimal, because 

cottonseed-derived food (i.e., oil and linters) goes through extensive processing, and 

consumption of cotton gin by-product by livestock will not result in a change to the current 

animal by-product commodity (food) tolerances.

The proposed use pattern for dicamba on DGT cotton falls within the use patterns evaluated 

by EPA in the dicamba RED; therefore, the proposed use of dicamba on DGT cotton does not 

present any new environmental exposure scenarios not previously evaluated and deemed 

acceptable by EPA, including estimates of drinking water exposure.

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 245 of 946

On the basis of the above analysis, the Deregulation in Whole and No Action Alternatives are 

similar regarding impacts on consumer health.

IV.E.1.d. Approval in Whole of DT Soybean and DGT Cotton

As discussed in detail above, there is no substantial difference for potential impacts to human 

health between the No Action and Deregulation in Whole Alternatives for DT soybean and 

DGT cotton. 

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with current glyphosatetolerant soybean systems and the dicamba and glufosinate-tolerant event DGT cotton with 

current glyphosate-tolerant cotton systems using traditional breeding techniques. Prior to the 

introduction of a GE-derived crop product to the marketplace, Monsanto conducts tests to 

assure that the product is as safe as its conventional counterpart under the intended use 

conditions. GE-derived crops for food and feed use undergo a voluntary consultation process 

with the U.S. FDA prior to release into the market. Monsanto completed the U.S. FDA 

consultation process for both DT soybean and DGT cotton. 

On the basis of the characteristics of MON 87708 DMO, MON 88701 DMO, PAT (bar), the 

extensive compositional characterization of DT soybean and DGT cotton harvested seed, and 

the overall assessment of DT soybean and DGT cotton as related to human health, impacts on 

consumer health from the Deregulation in Whole Alternative are not expected to differ from 

those of the No Action Alternative.

Monsanto has submitted to EPA applications to amend EPA Reg. No. 524-582, a low-volatility 

DGA salt formulation, to register a new use patterns for dicamba on DT soybean and DGT 

cotton as mentioned above. The proposed use patterns fall within the use patterns evaluated 

by EPA in the dicamba RED, therefore the proposed use of dicamba on DT soybean and 

DGT cotton does not present any new environmental exposure scenarios not previously 

evaluated and deemed acceptable by EPA, including estimates of drinking water exposure.

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. 

On the basis of the above analysis, the Deregulation in Whole and No Action Alternatives for 

DT soybean and DGT cotton are similar regarding impacts on consumer health.

IV.E.2. Worker Health

IV.E.2.a. No action alternative

Under the No Action Alternative, DT soybean and DGT cotton would remain regulated 

articles and would not be commercially available to growers. It is likely that growers will 

continue to use herbicides in soybean and cotton production, and use the glyphosate-tolerant

soybean and cotton systems along with additional herbicides where needed or recommended to 

control hard-to-control or glyphosate-resistant weeds. Growers may also choose to use other 

herbicide-tolerant soybean and cotton varieties, use a combination of alternative herbicides 

registered for use in soybean or cotton, use traditional tillage practices or use hand-weeding 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 246 of 946

especially in cotton. The continued use of dicamba on a small number of soybean and cotton 

acres would also be expected. Therefore, agricultural workers will be exposed to residues of

dicamba as well as other herbicides under the No Action Alternative. Use of increased tillage 

may represent a small increase in risk of machinery-related injury, if it results in increased trips 

across the field, and/or a small increase in strains and repetitive motion injury, if it results in 

increased hand-weeding, for agricultural workers. On the basis of the analysis above, the 

deregulation in whole and No Action Alternatives involve the continued use of herbicides for 

production of soybean and cotton. Thus the impacts to agricultural worker health for 

Deregulation in Whole and the No Action Alternative are not considered materially different. 

IV.E.2.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to have 

significant impacts on worker health. Cotton farmers would continue to implement manual 

labor, such as hand-weeding, in order to achieve satisfactory control of Palmer amaranth. 

It is expected that under the Deregulation in Whole Alternative for DT soybean, DT soybean 

will be integrated into the glyphosate-tolerant soybean system using traditional breeding 

techniques. DT soybean would be an option for growers where glyphosate-resistant weeds may 

already be present or where application of an herbicide with a different mode-of-action would 

aid in weed control or the implementation of weed resistant management practices.

There is no notable worker safety issue related directly to exposure to DT soybean. As 

described elsewhere, DT soybean is as safe as conventional soybean for use as food or feed. 

MON 88701 DMO has no safety concerns that would result in adverse effects to workers 

exposed to DT soybean plant tissues. 

Agricultural workers can be exposed to dicamba during the herbicide application or upon 

re-entry into treated DT soybean fields. Under the proposed label, which is currently pending 

before EPA, dicamba could be applied as a preemergent treatment on DT soybean at rates up 

to 1 lb a.e. per acre and then again in two sequential 0.5 lb a.e. per acre postemergent 

treatments up to the R1/R2 growth stage using a ground application method. The EPA 

conducted a comprehensive occupational exposure assessment as part of the dicamba 

reregistration in 2006 and concluded no unreasonable risk to agricultural workers from ground 

and aerial dicamba applications to soybean at rates up to 2 lb a.e. per acre when required 

personal protective equipment is worn (U.S. EPA 2009d). The application scenario evaluated 

by EPA encompasses the application method and rates for dicamba applied to DT soybean. 

Therefore, the deregulation of DT soybean does not present a significant impact to the health 

of agricultural workers.

Overall, when compared to the Deregulation in Whole Alternative, the No Action Alternative

may represent a small increase in risk of machinery-related injury, if it results in increased trips 

across the field, the No Action Alternative for DGT cotton and DT soybean may also result in 

a small increase in strains and repetitive motion injury, if it results in increased hand-weeding.

The deregulation of DT soybean does not present a significant impact to the health of 

agricultural workers.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 247 of 946

IV.E.2.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to have 

significant impacts on worker health.

It is expected that under the Deregulation in Whole Alternative for DGT cotton, DGT cotton 

will be integrated into the current glyphosate-tolerant cotton systems using traditional breeding 

techniques. DGT cotton would be an option for growers where glyphosate-resistant weeds 

may already be present or where application of an herbicide with a different mode-of-action 

would aid in weed control or the implementation of weed resistant management practices. 

As discussed above, DGT cotton is as safe as commercially cultivated cotton for use as food or 

feed. MON 88701 DMO and PAT (bar) have no safety concerns that would result in adverse 

effects to workers exposed to DGT cotton plant tissues.

Agricultural workers can be exposed to dicamba and/or glufosinate during the herbicide 

application or upon re-entry into treated DGT cotton fields. Pending EPA approval, dicamba 

would be authorized to be applied up to 1.0 lb a.e. per acre prior to planting up to the 

emergence of cotton, and post-emergence in-crop up to 0.5 lbs a.e. per acre per application, 

could be applied up through seven days prior to harvest. The EPA conducted a comprehensive 

occupational exposure assessment as part of the dicamba reregistration in 2006 and concluded 

no unreasonable risk to agricultural workers from ground and aerial dicamba applications at 

rates up to 2 lbs a.e. per acre when required personal protective equipment is worn (U.S. EPA 

2009d). The application scenario evaluated by EPA encompasses the application method and 

rates for dicamba applied to DGT cotton. No label changes will be needed for glufosinate. 

Therefore, the deregulation of DGT cotton does not present a significant impact to the health 

of agricultural workers. 

In summary, in terms of impacts to workers, the difference between the No Action and the 

Deregulation in Whole Alternatives is primarily the difference in the types of herbicides that 

may be used, tillage operations, and hand-weeding for DGT cotton. EPA has determined that 

when herbicides are used in accordance with their labels, no unreasonable adverse impacts will 

result. As discussed above, EPA’s conclusions are based on comprehensive evaluations and 

risk assessments. 

Overall, when compared to the Deregulation in Whole Alternative, the No Action Alternative

may represent a small increase in risk of machinery-related injury, if it results in increased trips 

across the field, and/or a small increase in strains and repetitive motion injury, if it results in 

increased hand-weeding. The deregulation of DT soybean does not present a significant impact 

to the health of agricultural workers.

IV.E.2.d. Approval in whole of both DT soybean and DGT cotton

It is expected that under the Deregulation in Whole, DT and DGT cotton would be integrated 

into the glyphosate-tolerant soybean and cotton systems using traditional breeding techniques. 

DT soybean and DGT cotton would be options for growers where glyphosate-resistant weeds 

may already be present or where application of an herbicide with a different mode-of-action 

would aid in weed control or the implementation of weed resistant management practices. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 248 of 946

As discussed above, DT soybean and DGT cotton are as safe as commercially cultivated 

soybeans and cotton for use as food or feed. MON 88701 DMO and PAT (bar) proteins have 

no safety concerns that would result in adverse effects to workers exposed to DT soybean or 

DGT cotton plant tissues.

Agricultural workers can be exposed to dicamba during the herbicide application or upon 

re-entry into treated DT soybean and DGT cotton fields. Monsanto has submitted to EPA 

applications to amend EPA Reg. No. 524-582, a low-volatility DGA salt formulation, to register 

a new use patterns for dicamba on DT soybean and DGT cotton as mentioned above. The 

proposed use patterns fall within the use patterns evaluated by EPA in the dicamba RED, 

therefore the proposed use of dicamba on DT soybean and DGT cotton does not present any 

worker health exposure scenarios not previously evaluated and deemed acceptable by EPA, 

including estimates of drinking water exposure.

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant 

cotton and is considered baseline. 

In summary, in terms of impacts to workers, the difference between the No Action and the 

Deregulation in Whole Alternatives is primarily the difference in the types of herbicides that 

may be used, tillage practices and the use of hand-weeding. EPA has determined that when 

herbicides are used in accordance with their labels, no unreasonable adverse impacts will result. 

As discussed above, EPA’s conclusions are based on comprehensive evaluations and risk 

assessments. 

Overall, when compared to the Deregulation in Whole, the No Action Alternative may 

represent a small increase in risk of machinery-related injury, if it results in increased trips 

across the field. The No Action Alternative for DGT cotton and DT soybean may also result 

in a small increase in strains and repetitive motion injury, if it results in increased hand-weeding.

The deregulation of DT soybean and DGT cotton does not present a significant impact to the 

health of agricultural workers.

IV.F. ANIMAL FEED AND ANIMAL HEALTH

This section discusses the environmental consequences of deregulating DT soybean and/or

DGT cotton or taking No Action. Potential impacts from the cultivation of DT soybean and 

DGT cotton occur from exposure to the inserted genes and proteins in DT soybean and DGT 

cotton and from dicamba residues in animal feed from the use of dicamba in soybean and 

cotton.

The potential impacts on animal feed associated with the introduction of DT soybean and 

DGT cotton and increased applications of dicamba are separately discussed below. However, as 

discussed elsewhere in this report, Congress transferred regulatory authority over herbicides 

from USDA to EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or 

herbicide resistance, and no authority to consider herbicide impacts under the PPA. 

Nonetheless, because APHIS indicated in its Notice of Intent to Prepare an Environmental 

Impact Statement (78 Fed. Reg. 28796, May 16, 2013) that it would be considering herbicide 

effects and herbicide resistance as part of the NEPA process, Monsanto has included a 

discussion of herbicide impacts in the following section. Importantly, however, Monsanto 
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believes that APHIS has no legal obligation under NEPA to consider herbicide impacts or 

herbicide resistance in any Environmental Impact Statement or Environmental Assessment. 

See DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an agency has no ability to 

prevent a certain effect due to its limited statutory authority over the relevant actions, the 

agency cannot be considered a legally relevant “cause” of the effect, and is therefore not 

required to analyze the environmental impact of an action it could not refuse to perform). See

also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at *16-17 (9th 

Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not exhibit any risk of 

plant pest harm, APHIS must deregulate it since the agency does not have jurisdiction to 

regulate organisms that are not plant pests.”).

IV.F.1. No Action Alternative for Both DGT Cotton and DT Soybean

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated by APHIS. Current availability and usage of commercially cultivated (both GE and 

non-GE) soybean and cotton are expected to remain the same, and the use of dicamba 

herbicide in soybean and cotton would remain unchanged, including the pre-harvest treatments

in soybean which result in dicamba residues in soybean seed up to the 10 ppm tolerance. 

Exposure to existing conventional and GE soybean and cotton products used for animal feed 

would remain unchanged (see Section II.F. for a description of the use of soybean and cottonderived products for animal feed). Other herbicides are available and would be used in soybean

and cotton as needed to control weeds in conventional and herbicide-tolerant soybean and 

cotton. The availability of safe and nutritional animal feed from existing soybean and cotton 

crops, including crops containing dicamba (soybean only) or other herbicide residues from 

currently established uses, will continue

IV.F.2. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the No Action Alternative for DGT cotton is not expected to have 

significant impacts on animal feed or animal health.

The difference between the Deregulation in Whole and the No Action Alternative is expected 

to be integration of DT soybean into the glyphosate-tolerant soybean system using traditional 

breeding techniques. Under the Deregulation in Whole Alternative, there is potential for 

cultivation of soybean seed containing the DT trait to proactively manage and prevent the 

evolution and development of herbicide-resistant weeds. For those acres where glyphosateresistant weeds may already be present or where application of an herbicide with a different 

mode-of-action would aid in weed control or the implementation of weed resistant 

management practices, the cultivation of soybean containing the DT trait would be an option 

for growers.

Potential impacts to the safety of animal feed from widespread cultivation of DT soybean 

would be primarily based on the possible effects of the introduced MON87708 DMO protein

that provides tolerance to dicamba and the dicamba residues from the application of dicamba 

that would be present in animal feed. There is no meaningful risk to animal health from dietary 

exposure to MON 87708 DMO or toxic properties associated with MON 87708 DMO. 

Furthermore, the composition of the grain and forage produced by DT soybean is equivalent to 

conventional soybean. This information on the safety of MON 87708 DMO and composition 
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of DT soybean seed as detailed in Appendix G indicate that there would be no negative impact 

on the safety or nutritional quality of animal feed from the cultivation of DT soybean. 

Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DT soybean on October 11, 2011 (BNF 

No. 00125, Monsanto, 2011). As a part of its evaluation, FDA reviewed information on the 

identity, function, and characterization of the genes, including expression of the gene products 

in DT soybean, as well as information on the safety of MON 87708 DMO, including a dietary 

risk assessment.

Dicamba is presently applied to less than 1% of soybean acres using pre-plant and pre-harvest 

burn down applications. Under the Deregulation in Whole Alternative, dicamba will be used 

on more soybean acres and a higher percentage of soybean-derived animal feeds will contain 

dicamba residues. However, dicamba residue levels in DT soybean harvested seed or processed 

meal will be significantly lower compared to levels originating from the current pre-harvest 

soybean use (approximately 100-fold lower, based on <0.1 ppm residue in DT soybean seed 

compared to established 10 ppm tolerance - see Appendix E for residue levels in seed). As part 

of the pesticide tolerance setting process for dicamba (40 CFR 180.227), the EPA concluded 

that residues of dicamba up to 10 ppm in soybean seed (grain) are safe (reasonable certainty of 

no harm as defined by FFDCA) for animal consumption. Additionally, Monsanto has 

petitioned the EPA to establish new feed tolerances for soybean forage and hay to allow DT 

soybean forage and hay to be fed to livestock. Dietary exposure to livestock from the feeding 

of DT soybean forage and hay does not result in an increase in the maximum dietary (feed) 

exposure of dicamba evaluated and deemed safe by EPA. 

DT soybean, MON 87708 DMO and dicamba residues in DT soybean-derived feed 

components do not affect the safety or nutritional quality of animal feed. The deregulation of 

DT soybean will not result in a significant impact on animal feed, and consequently to animal 

health. Therefore, the Deregulation in Whole and the No Action Alternatives are the same 

regarding their effects an animal feed.

IV.F.3. Approval In Whole of DGT Cotton, but not DT Soybean

As discussed above, the No Action Alternative for DT soybean is not expected to have 

significant impacts on animal feed or animal health.

The difference between the No Action and the Deregulation in Whole Alternatives for DGT 

cotton would be the gradual integration of the dicamba and glufosinate-tolerant event DGT 

cotton with the current glyphosate-tolerant cotton systems using traditional breeding 

techniques. Under the Deregulation in Whole Alternative, domestic animals, mainly ruminants, 

would be exposed to feed products derived from DGT cotton. As discussed in Section II.F, 

cottonseed meal is an excellent protein source for ruminants, and hulls and gin by-products 

may be used for roughage. 

Potential impacts to the safety of animal feed from widespread cultivation of DGT cotton

would be primarily based on the possible effects of the introduced MON 88701 DMO and 

PAT (bar) proteins that provide tolerance to dicamba and glufosinate, respectively and the 

dicamba and glufosinate residue that would be in animal feed. 
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Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DGT cotton in April 2013. As a part of 

its evaluation, FDA reviewed information on the safety of the MON 88701 DMO and PAT 

(bar) protein and DGT cotton seed, including a dietary risk assessment. MON 88701 DMO 

and PAT (bar) were fully characterized and the enzymatic activity of MON 88701 DMO was 

found to be specific for dicamba when tested using structurally similar cotton endogenous 

substrates (see Appendix G of this Environmental Report). The specificity of PAT proteins 

has been extensively documented in the literature. Neither protein has relevant amino acid 

sequence similarities to known allergens, toxins or other proteins that may have adverse effects 

on mammals. MON 88701 DMO and PAT (bar) were each rapidly digested in simulated gastric 

and intestinal fluids, a characteristic shared among many proteins with a history of safe 

consumption. Rapid digestion of MON 88701 DMO and PAT (bar) in simulated gastric and 

intestinal fluids indicates that it is highly unlikely that MON 88701 DMO or PAT (bar) would 

reach absorptive cells of the intestinal mucosa. Neither MON 88701 DMO nor PAT (bar) 

caused any observable adverse effects when tested in mouse acute oral toxicity analyses. 

Furthermore, detailed compositional analyses, in accordance with OECD guidelines, 

demonstrated that levels of key nutrients and anti-nutrients in DGT cottonseed are comparable 

to levels in the conventional cotton control, Coker 130, and several commercial reference 

cotton varieties. This information on the safety of DMO and composition of DGT cotton as 

detailed in Appendix G indicate that there would be no negative impact on the safety or 

nutritional quality of animal feed from the cultivation of DGT cotton. 

The cultivation of DGT cotton will not change the number of cotton acres cultivated in the 

U.S., and the extent in which cotton acres are cultivated will continue to be based on the same 

market-based drivers that exist today.

The DMO protein allows for a broadened application window of dicamba to DGT cotton. The 

PAT (bar) protein is the same protein present in commercial glufosinate-tolerant cotton; and 

the use of glufosinate on DGT cotton is also the same as for existing commercial glufosinatetolerant cotton varieties. Upon deregulation, DGT cottonseed produced for animal feed may 

contain dicamba and or glufosinate residues from the application of dicamba and/or 

glufosinate. Dicamba is presently applied to approximately 10% of cotton acres using pre-plant 

burn down applications. Under the Deregulation in Whole Alternative, dicamba will be used 

on more cotton acres and a higher percentage of cotton-derived animal feeds will contain 

dicamba residues. 

Under the Deregulation in Whole Alternative, domestic animals, mainly ruminants, would be 

exposed to feed products derived from DGT cotton. DGT cotton, MON 88701 DMO, PAT 

(bar), as well as dicamba and glufosinate residues in DGT cotton-derived feed components do 

not affect the safety or nutritional quality of animal feed. The deregulation of DGT cotton will 

not result in a significant impact on animal feed, and consequently to animal health. Therefore, 

the Deregulation in Whole and the No Action Alternatives are the same regarding their effects 

an animal feed.

IV.F.4. Approval in Whole of DT Soybean and DGT Cotton

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with current glyphosatetolerant soybean systems and the dicamba and glufosinate-tolerant event DGT cotton with 
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current glyphosate-tolerant cotton systems using traditional breeding techniques. DT soybean 

and DGT cotton would be an option for growers where glyphosate-resistant weeds may already 

be present or where application of an herbicide with a different mode-of-action would aid in 

weed control or the implementation of weed resistant management practices. 

As discussed above, DT soybean and DGT cotton are as safe as commercially cultivated 

soybeans and cotton for use as animal feed. Information on the safety of MON 87708 DMO, 

MON 88701, PAT (bar), and DT soybean and DGT cotton compositional analyses indicate that 

there would be no negative impact on the safety or nutritional quality of animal feed from the 

cultivation of DT soybean or DGT cotton. The deregulation of DT soybean and DGT cotton

will not result in a significant impact on animal feed, and consequently to animal health. 

Therefore, the Deregulation in Whole and the No Action Alternatives are the same regarding 

their effects an animal feed.

IV.G. SOCIOECONOMIC IMPACTS

IV.G.1. Domestic Economic Environment: Soybean and Cotton

In 2012, 77 million acres of soybeans were cultivated in the U.S., yielding 3.0 billion bushels at a 

value of 43.2 billion U.S. dollars (USDA-NASS, 2013h). The majority of soybeans produced in 

the U.S. are utilized domestically for animal feed, with lesser amounts and by-products used for 

oil or fresh consumption (USDA-ERS, 2012b). Total acreage planted to soybeans in the US is 

projected to remain at 2012 levels in 2013, then falling slightly to 76 million acres for 2014 

through 2021. Average yields are projected to increase from 44.5 bushels per acre in 2013 to 

48.1 bushels/acre in 2021 (USDA-OCE, 2012).

The value of cotton production reached $7.27 billion in the U.S. in 2011 (USDA-NASS 2012a). 

In comparison, corn and soybean production values in 2011 were $76.46 and $35.78 billion, 

respectively (USDA-NASS 2012a).

Cotton producers in the U.S. are among the most technically advanced in the world, annually 

harvesting about 17 million bales or 7.2 billion pounds of cotton (US-EPA, 2009). The USDA 

ERS notes that U.S. cotton productivity has increased in recent years as a result of 

technological advancements, including biotechnology-derived varieties (Meyer et al. 2007). 

Herbicide-tolerant cotton is one of the most widely and rapidly adopted crops in the U.S., 

followed by insect-resistant cotton (Fernandez-Cornejo and Caswell 2006; USDA-ERS 2010b). 

By the adoption of new technologies, including agronomic traits delivered through 

biotechnology, the yields of cotton lint per acre in the U.S. ranks among the highest in the 

world (USDA-NASS 2011c). The adoption of postemergent herbicide-tolerant varieties 

provides opportunities to apply fewer herbicides and to reduce field cultivation (University of 

California 2009; USDA-NASS 2011c).

IV.G.1.a. No Action Alternative for Both DGT Cotton and DT Soybean

Under the No Action Alternative, DT soybean and DGT cotton would continue to be 

regulated. Growers and other parties who are involved in production, handling, processing, or 

consumption of soybean and cotton would not have access to DT soybean or DGT cotton, but 

would continue to have access to commercial soybean and cotton varieties, including GE 

soybean and cotton varieties that are no longer subject to the regulatory requirements of 7 CFR 
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part 340 or the plant pest provisions of the Plant Protection Act. Domestic growers will 

continue to utilize conventional soybean and cotton varieties based upon availability and market 

demand.

Contemporary soybean and cotton crop management practices include specific measures to 

protect and preserve varietal identity, as well as a wide range of agronomic inputs. These 

management practices vary from grower to grower, and are unaffected by the No Action 

Alternative. Management practice considerations associated with the current cultivation of 

herbicide-tolerant soybeans would include adherence to label use restrictions for any herbicides 

applied to the crop. Growers adopting GE varieties incur a cost premium to acquire the seed 

(NRC 2010). These technology fees are imposed by the product developer to cover their 

research and development costs, and GE seeds are traditionally more expensive than 

conventional seed (NRC 2010).

Growers cultivating GE crops all pay such technology fees. The NRC suggests that the benefits 

associated with the adoption of GE crops, including a reduction in agronomic inputs and 

increases in yield outweigh the extra costs of the GE seed (NRC 2010). All growers adopting 

GE crops would incur these fees. These costs are unaffected by the No Action Alternative.

The existence of glyphosate-resistant weed biotypes has been identified as an economic 

concern (NRC 2010). In the areas of the U.S. where they occur, glyphosate-resistant weed 

biotypes have the potential to reduce the effectiveness and economic benefits of glyphosatetolerant crop systems (Owen, et al. 2011) (Weirich, et al. 2011). However, growers continue to 

use glyphosate and build their weed management programs around glyphosate, because even in 

the presence of certain resistant weed biotypes, glyphosate continues to provide many benefits 

to farmers. Current research advocates using herbicides presenting multiple modes of action to 

manage these weeds (Owen et al. 2011). Growers would select other herbicides based on the 

targeted weed spectrum and types and level of herbicide resistance present in a particular field

(Purdue Extension 2012). Dicamba is one such herbicide offering another mode-of-action to 

control glyphosate-resistant weeds.

Where necessary to manage herbicide-resistant weeds, growers in certain areas of the U.S. have 

increased herbicide application rates, increased the number of herbicide applications, and have 

returned to more traditional tillage practices (NRC 2010). The economic impacts of 

glyphosate-resistant weeds in certain areas of the U.S. are a direct result of increased inputs: 

additional herbicides are required to control the weeds; fuel costs increase as heavy equipment 

is used more frequently in the field for chemical application; and tillage and labor and 

management hours increase in association with the application of additional herbicides and 

machinery use (NRC 2010; Weirich et al. 2011). There is also the potential additional cost from 

the reduction in yield that can occur as a result of competition of the crop with the weeds 

(NRC 2010; Weirich et al. 2011).

Under the No Action Alternative, growers will continue to benefit from the adoption and 

cultivation of GE crops, including the commensurate reduction in costs associated with tillage 

and pesticide applications (Duke and Powles 2009). At the same time, those growers in certain 

areas of the U.S. managing herbicide-resistant weeds have the potential to incur increased costs 

to employ management techniques, which may include increased pesticide use and increased 

tillage. These trends are unaffected by the No Action Alternative.
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IV.G.1.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, approval of the No Action Alternative for DGT cotton growers will 

continue to benefit from the adoption and cultivation of GE crops, including the 

commensurate reduction in costs associated with tillage and pesticide applications (Duke and 

Powles 2009). Those growers in certain areas of the U.S. managing herbicide-resistant weeds 

have the potential to incur increased costs to employ a wide range of management techniques, 

which may include increased pesticide use, increased tillage and/or hand-weeding. 

It is expected that under the Deregulation in Whole Alternative for DT soybean, DT soybean 

will be integrated into the glyphosate-tolerant soybean system using traditional breeding 

techniques. DT soybean would be an option for growers where glyphosate-resistant weeds may 

already be present or where application of an herbicide with a different mode-of-action would 

aid in weed control or the implementation of weed resistant management practices. 

The adoption of DT soybean is expected to help maintain the economic and non-pecuniary 

benefits growers have realized using the glyphosate-tolerant system. Adopters of DT soybean 

may realize savings in weed management costs through reduced expenditure on herbicides,

reduced application costs for growers who reduce the number of trips across the field, and 

reduced tillage costs. In addition, growers who may be experiencing yield losses due to 

competition from glyphosate-resistant weeds may avoid these losses through improved weed 

control. The short term benefits of the introduction of the technology will be highly dependent 

on the price of the technology and herbicide to growers, which will also impact the extent of 

adoption. Other benefits include time and labor savings to growers through the simplicity and 

flexibility of the dicamba and glyphosate weed control system over alternative herbicides that 

are authorized for use in soybean production. In addition, the ability to use dicamba in 

combination with glyphosate will further preserve the benefits the glyphosate-tolerant system 

has provided in the form of increasing adoption of conservation tillage acres. Monsanto and 

academics recommend the use of a third herbicide mode-of-action with soil residual activity as 

part of a comprehensive weed resistance management program to assure that at least two 

effective modes-of-action are always used in the cultivated soybean field. The cultivation of 

DT soybean provides a method to mitigate the evolution and development of glyphosateresistant weeds and resistance to other herbicide classes due to the use of multiple herbicide 

modes-of-action in the DT soybean weed management system. This benefit is expected to 

outweigh additional costs of controlling resistant weeds through the dicamba and glyphosate 

weed control system.

Monsanto anticipates that DT soybean could replace currently available soybean varieties and 

may be selected by growers of conventional soybean varieties making a change to a GE variety. 

The commercialization of DT Soybean, however, is unlikely to have significant impact on the 

total acreage planted to soybeans, since larger market forces that influence the price of soybeans 

are more influential in the planting decisions that growers make. 

Soybean composition greatly affects its viability as a component of animal feed. Soybean meal 

generally contains 50 percent protein by dry weight and is an important component of soybean 

production. An additional 19 percent (by weight) of domestically produced soybeans are used 

to produce oil (USB, 2011a). The fatty acid content of soybean grain is important for the 

domestic soybean oil industry, as the soybean oil profile affects melting point, oxidative 
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stability, and chemical functionality, ultimately determining the market value/marketability of 

the product (APAG 2011). 

A determination of nonregulated status of DT soybean is expected to have similar impacts on 

the domestic economic environment as the No Action Alternative. Comparison of DT 

soybean with conventional soybean demonstrated no significant differences in fatty acid or 

crude protein content. Thus, market sector use of DT soybean under the Preferred Alternative 

is unlikely to be substantially different from market use of conventional soybean, as the primary 

factors of oil and protein content are not substantially different between the two soybean 

varieties.

Under the Approval in Whole Alternative, trends related to the domestic economic 

environment are unlikely to be substantially different than what would occur in the No Action 

Alternative.

IV.G.1.c. Approval in Whole of DGT Cotton, but not DT Soybean

Under the No Action Alternative, DT soybean and growers will continue to benefit from the 

adoption and cultivation of GE crops, including the commensurate reduction in costs 

associated with tillage and pesticide applications (Duke and Powles 2009). Those growers in 

certain areas of the U.S. managing herbicide-resistant weeds have the potential to incur 

increased costs to employ a wide range of management techniques, which may include

increased pesticide use, increased tillage, and hand weeding.

The adoption of DGT cotton is expected to help maintain the economic and non-pecuniary 

benefits growers have realized using the glyphosate-tolerant system. Adopters of DGT cotton 

may realize savings in weed management costs through reduced expenditure on herbicides, 

reduced application costs for growers who reduce the number of trips across the field, and 

reduced tillage costs. In addition, growers in certain areas of the U.S. who are experiencing 

yield losses due to competition from glyphosate-resistant weeds may avoid these losses through 

improved weed control. The short term benefits of the introduction of the technology will be 

highly dependent on the price of the technology and herbicide to growers, which will also 

impact the extent of adoption. Other benefits include time and labor savings to growers 

through the simplicity and flexibility of the dicamba, glufosinate, and glyphosate weed control 

system over alternative herbicides that are authorized for use in cotton production. In addition, 

the ability to use dicamba in combination with glyphosate or glufosinate will further preserve 

the benefits the glyphosate-tolerant system has provided in the form of increasing adoption of 

conservation tillage acres. Monsanto and academics recommend the use of a third herbicide 

mode-of-action with soil residual activity as part of a comprehensive weed resistance 

management program to assure that at least two effective modes-of-action are always used in 

the cultivated cotton field. The cultivation of DGT cotton provides a method to mitigate the 

evolution and development of glyphosate-resistant weeds and resistance to other herbicide 

classes due to the use of multiple herbicide modes-of-action in the DT soybean weed 

management system. This benefit is expected to outweigh additional costs of controlling 

resistant weeds through the dicamba, glufosinate, and glyphosate weed control system.

Monsanto anticipates that DGT cotton could replace currently available cotton varieties and 

may be selected by growers of conventional cotton varieties making a change to a GE variety. 

However, availability of DGT cotton is not expected to result in an increase in cotton acreage; 
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as discussed in Section II.G.2. of this Environmental Report, global cotton prices are the main 

factor contributing to the variation in value of the cotton production from year to year—and 

thus is likely to be the primary determinant of cotton acreage. 

While Monsanto anticipates that DGT cotton could replace existing GE cotton varieties 

currently in the market, specific economic projections are not provided. To the extent that the 

planting of DGT cotton results in a potential decrease in herbicide applications, farms adopting 

DGT cotton might experience an increase in net income. However, net income differentials 

cannot be projected. However, as Monsanto anticipates that DGT cotton would only replace 

existing GE cotton varieties and not result in increased cotton acreage, resulting socioeconomic

impacts are expected to be similar to the No Action Alternative.

IV.G.1.d. Approval in Whole of Both DGT Cotton and DT Soybean

As discussed in detail above, in terms of potential impacts of DT soybean or DGT cotton on 

domestic economic factors, there is no substantial difference between the No Action and 

Deregulation in Whole Alternatives. While Monsanto anticipates that DT soybean and DGT 

cotton could replace existing GE soybean and cotton varieties currently in the market, specific 

economic projections are not provided. To the extent that the planting of DT soybean and 

DGT cotton results in a potential decrease in herbicide applications, farms adopting DT 

soybean and DGT cotton might experience an increase in net income. However, net income 

differentials cannot be projected. However, as Monsanto anticipates that DT soybean and 

DGT cotton would only replace existing GE soybean and cotton varieties and not result in 

increased soybean or cotton acreage, resulting socioeconomic impacts are expected to be 

similar to the No Action Alternative.

IV.G.2. Trade Economic Environment

The U.S. produces approximately one-third of the global soybean supply (ASA 2012). In 2011, 

the U.S. exported 1.3 billion bushels of soybean, which accounted for 37 percent of the world’s 

soybean exports (USDA-FAS 2013b). The global demand for soybeans is expected to increase 

by a full third over 2011 consumption in the next ten years. China is expected to account for 

91 percent of the increased demand (FAPRI 2012; Hartnell 2010). China is predicted to import 

69 percent of the total soybean market by 2021/2022 (FAPRI, 2012). The USDA has predicted 

that U.S. exports will remain flat during much of this period, as a result of increase in domestic 

consumption and competition from South America (FAPRI 2012; USDA-ERS, 2013d).

Cotton is a crop that is primarily grown for fiber used in textiles. After ginning of the primary 

commodity, fiber, the cottonseed and cottonseed by-products (meal, hulls, linters, and oil) are 

utilized for various feed and industrial components. Data from 2010/2011 show that most of 

the world’s cotton production (116.40 million bales annually) is grown in China (30.5 million 

bales), India (26.4 million bales), the United States (18.1 million bales), Brazil (9.0 million), and 

Pakistan (8.6 million bales)(USDA-FAS 2012) . In 2010/2011, the U.S. supplied over 14 

million bales of the world’s cotton exports, accounting for approximately 40% of the total 

world export market for cotton (USDA-FAS 2011b). China, Bangladesh, Indonesia, and 

Turkey are major importers of cotton fiber. The largest customers for U.S. cotton fiber are 

Asia and Mexico, due to the relatively large textile manufacturing industry in those areas 

(NCCA 2010a).
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Starting in the 1930s, the U.S., Canada, and Europe entered into trade agreements that set limits 

on the amount of foreign-made apparel and textiles that could be imported into the U.S. The 

last of these agreements, the Multifibre Arrangement (MFA), ended in 2005 (Meyer et al. 2007). 

Consumption of cotton by U.S. textile mills peaked in 1997. Since then, U.S. mill use of cotton 

has dropped by approximately 50% in 2005 and by nearly 70% in 2009 (USDA-ERS 2009). 

This change in foreign-made textile imports resulted in increased global competition for import 

and export of raw cotton, as well as finished textiles (Meyer et al. 2007). U.S. consumer 

demand for cotton products remains strong, but imported clothing now accounts for most 

purchases by U.S. consumers (USDA-ERS 2009). The USDA-ERS reports that U.S. cotton 

mills consumed 60% of the domestic cotton through the 1990s, but not long after the end of 

MFA quotas, 70% of the U.S. cotton lint was exported (Meyer et al. 2007).

IV.G.2.a. No Action Alternative for Both DT Soybean and DGT Cotton

Under the No Action Alternative, there is unlikely to be any change to the current soybean or 

cotton markets. Most (91%) of the soybean varieties currently cultivated in the U.S. are GE 

varieties and it is predicted that this will not change substantially (USDA-ERS, 2012a). It is 

projected that approximately 90% of the cotton produced will continue to be planted with the 

currently available GE cotton (USDA-ERS, 2010c). Both U.S. soybean and cotton will 

continue to play a role in global production, and the U.S. will continue to be a supplier of 

soybeans and cotton in the international market but the extent of use will be subject to global 

market conditions.

Economic evidence shows that international trade and productivity is enhanced by the 

adoption of GE cotton and that these products can be channeled into suitable export markets. 

For example, increased global production of Bt cotton adoption led to a 3% reduction in the 

world cotton price (Frisvold and Reeves, 2007). This research also showed that individual 

countries obtained greater economic gains by adopting Bt cotton technology than if they did 

not adopt it, and further, found non-adopting regions to lose cotton market share to the 

adopting regions (Frisvold and Reeves, 2007). These conditions are not expected to change if 

DGT cotton remains a regulated article.

IV.G.2.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, the cropping and marketing decisions made by cotton growers are unlikely 

to be impacted by the No Action Alternative and it is expected that approximately 90% of the 

cotton produced will continue to be planted with the currently available GE cotton (USDAERS, 2010c). U.S. cotton will continue to play a role in global cotton production, and will 

continue to be a supplier in the international market but the extent of use will be subject to 

global market conditions.

A determination of nonregulated status of DT soybean is not expected to adversely impact 

international soybean markets. To the extent that adoption of DT soybean allows growers to 

reduce weed control costs, its introduction may enhance U.S. competitiveness in global

markets. To support commercial introduction of DT soybean in the U.S., Monsanto requested

import approval of DT soybean in key soybean export markets of the United States that have 

functioining regulatory systems. These include, but are not limited to: Canada, Mexico, Japan, 

the EU, South Korea, and China. Table IV.G-1 lists the current status of import approvals in 

key U.S. soybean export markets.
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Table IV.G-1. Status of Import Approvals of DT Soybean in Key US Soybean Export 

Markets

DT Soybean DT Soybean Stack1,2

Country Submission Approval Submission Approval

Canada Nov. 2010 Oct. 2012 Nov. 2012 Jan. 2013

Mexico Nov. 2011 July 2012 June 2012 Feb. 2013

Japan March 2011 Oct 2013 Sept. 2012 In review

Korea Feb. 2011 Oct. 2013 Jan. 2013 In review

Australia May 2011 May 2012 NA

EU Jan. 2011 In review March 2012 In review

China Oct. 2012 In review NA

Taiwan March 2011 April 2013 April 2013 In review

India April 2013 In review NA 

1

 DT soybean will be stacked with Roundup Ready 2 Yield (MON 89788). 

2

 Progeny (breeding stacks) of GE crops are not regulated by APHIS.

In general, a global launch (i.e., commercialization) may not be undertaken until the proper 

regulatory approvals have been obtained (I. Coates, 2012, Personal Communication). Approval 

in these export countries is intended to mitigate global sensitivities to GE productions and 

work in accordance with international regulations. The trade economic impacts associated with 

a determination of nonregulated status of DT soybean are anticipated to be very similar to the 

No Action Alternative.

IV.G.2.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, under the No Action Alternative, there is unlikely to be any change to the 

current soybean market. Most (91 %) of the soybean varieties currently cultivated in the U.S. 

are GE varieties and it is predicted that this will not change substantially (USDA-ERS, 2012a).

U.S. soybeans will continue to play a role in global soybean production, and the U.S. will 

continue to be a supplier in the international market.

A determination of nonregulated status of DGT cotton is not expected to adversely impact 

international cotton markets. To the extent that adoption of DGT cotton allows growers to 

reduce weed control costs, its introduction may enhance U.S. competitiveness in global 

markets. To support commercial introduction of DGT cotton in the U.S., Monsanto requested

import approval of DGT cotton in key cotton export markets of the United States that have 

functioining regulatory systems. These include submissions to the relevant regulatory 

authorities in Canada, Mexico, the European Union (EU), and Japan, among others. Table 

IV.G-2 lists the current status of import approvals in U.S. cotton export markets.
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Table IV.G-2. Status of Import Approvals of DGT Cotton in Key US Cotton Export 

Markets

DGT Cotton DGT Cotton Stacks1,2

Country Submission Approval Submission Approval

Canada June 2012 In review

Not yet 

submitted -

Mexico May 2013 In review

Not yet 

submitted -

Japan Nov. 2012 In review June 2013 In review

Korea Oct. 2012 In review

Not yet 

submitted -

Australia Jan. 2013 In review NA -

EU Feb. 2013 In review

Not yet 

submitted -

China Not yet submitted - NA

Philippines Not yet submitted -

Not yet 

submitted -

1

 DGT will be stacked with Roundup Ready Flex Cotton and Bollgard II (MON 88913 and 

MON 15985).

2

 Progeny (breeding stacks) of GE crops are not regulated by APHIS.

A determination of nonregulated status of DGT cotton is not expected to adversely impact the 

trade economic environment and may potentially enhance it through the subsequent 

development and global adoption of DGT cotton could provide another herbicide-tolerant 

management choice for growers. A reduction in costs for domestic growers associated with the 

reduction herbicide use may make U.S. producers more competitive in the global market. The 

trade economic impacts associated with a determination of nonregulated status of DGT cotton 

are anticipated to be very similar to the No Action Alternative.

IV.G.2.d. Approval in Whole of Both DT Soybean and DGT Cotton

It is expected that under the Deregulation in Whole, DT soybean and DGT cotton would be 

integrated into the glyphosate-tolerant soybean and cotton systems using traditional breeding 

techniques. DT soybean and DGT cotton would be options for growers where glyphosateresistant weeds may already be present or where application of an herbicide with a different 

mode-of-action would aid in weed control or the implementation of weed resistant 

management practices. 

To the extent that adoption of DT soybean allows growers to reduce weed control costs, its 

introduction may enhance US competitiveness in global markets. To support commercial 

introduction of DT soybean and DGT cotton in the U.S., Monsanto intends to submit dossiers 

to request import approval of DT soybean and DGT cotton to the proper regulatory 

authorities of several countries that already have regulatory processes for GE soybean and 

cotton in place.
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In general, a global launch (i.e., commercialization) may not be undertaken until the proper 

regulatory approvals have been obtained (I. Coates, 2012, Personal Communication). Approval 

in these export countries is intended to mitigate global sensitivities to GE productions and 

work in accordance with international regulations. The trade economic impacts associated with 

a determination of nonregulated status of DT soybean and DGT cotton are anticipated to be 

very similar to the No Action Alternative.

IV.G.3. The Organic Segment

IV.G.3.a. No Action Alternative for Both DT Soybean and DGT Cotton

Current availability, market demand, and acreage of organic soybean and cotton are anticipated 

to remain unchanged under the No Action Alternative. Similar to market trends for other U.S. 

organic products, demand of organic soybean and cotton is likely to increase (USDA-ERS, 

2007). Despite this increasing demand, however, the share of U.S. organic soybean and cotton 

production remains relatively small and steady. While this flat production of U.S. organic 

soybean and cotton correlates with an increase in GE soybean adoption, there is little or no 

evidence to suggest a cause-and-effect relationship. These trends are expected to be unaffected 

by the No Action Alternative.

IV.G.3.b. Approval in Whole of DT Soybean, but not DGT Cotton

As discussed above, approval of the No Action Alternative for DGT cotton is not expected to 

impact organic cotton production.

In 2011, out of 77 million acres of total soybean production, there were approximately 96,000 

acres of organic soybean produced across 1,203 farms in the United States (USDA-NASS 

2012e). This represented about 0.13 percent of total U.S. soybean production in 2011 (USDANASS 2011b; 2012e). This proportion is not anticipated to substantially change in spite of 

rising domestic demand, due in part to increasing competition and imports from international 

organic soybean producers (USDA-ERS, 2007). Therefore, domestic demand for organic 

soybean and organic soybean products appear to be sustained by increasing imports from 

international organic soybean producers (USDA 2007)( USDA-ERS, 2007).

It is not likely that organic farmers will be substantially affected by a determination of 

nonregulated status of DT soybean. Soybean is primarily a self-pollinated plant (OECD 2010), 

and there is no reason to suspect that the biology of DT soybean will increase its potential to 

outcross with soybean varieties utilized in organic soybean production (USDA-APHIS, 2012d). 

As set forth in Monsanto’s Petition for Nonregulated Status, field studies of DT soybean 

reproductive biology revealed no substantial differences in factors influencing reproductive 

potential, including pollen viability, date of emergence, date of 50 percent flowering, and date 

of maturity (See DT soybean petition). 

It is important to note that the current NOP regulations do not specify an acceptable threshold 

level for the adventitious presence of GE materials in a product labeled organic (USDA-AMS 

2010). The unintentional presence of the products of excluded methods will not affect the 

status of an organic product or operation when the operation has not used excluded methods 
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and has taken reasonable steps to avoid contact with the products of excluded methods 

(Ronald and Fouche 2006; USDA-AMS 2010). However, certain markets or contracts may 

have defined thresholds (Non-GMO Project 2012).

A determination of nonregulated status of DT soybean is unlikely to substantially affect U.S. 

organic soybean market conditions. In contrast to other U.S. organic crops, U.S. organic 

soybean production has not kept pace with demand, as discussed above (USDA-ERS 2010d). 

The increased demand for organic soybean in the U.S. has generally been met by increasing 

imports from international organic soybean producers (USDA 2007; USDA-ERS, 2007).

IV.G.3.c. Approval in Whole of DGT Cotton, but not DT Soybean

As discussed above, approval of the No Action Alternative for DT soybean is not expected to 

impact organic cotton production.

The USDA census of organic agriculture reported organic cotton farming on 30 farms in the 

U.S. in 2008, two in Arizona, three in New Mexico, four in California, and 21 in Texas (USDANASS 2008a). Texas (66%) and New Mexico (20%) together accounted for approximately 86% 

of the production. Based on USDA-ERS data, between 1997 and 2008, organic cotton acreage 

ranged from 9,213 acres in 2004 to 15,377 acres in 2008 (USDA-ERS 2008). In 2008 about 

0.16% of the total 9.41 million acres of cotton was produced organically (USDA-ERS 2008). In 

recent years, small and sporadic acreages of organic cotton production have been cultivated in 

other states, including Missouri, Illinois, Kansas, Tennessee, and Colorado (USDA-ERS 2010c). 

Based upon recent trend information, the presence of GE cotton varieties on the market has 

not affected the ability of organic production systems to maintain their market share. Between 

2000 and 2008, although 11 GE cotton events were deregulated and the percent of GE cotton 

in the market was near or above 90% and the acreage of organic cotton production remained at 

approximately 15,000 acres (USDA-APHIS 2013c; USDA-ERS 2008).

Most U.S. organic cotton growers sell their cotton products through a marketing cooperative, 

the largest of which is the TOCMC, with approximately 30 members (OTA 2012; TOCMC 

2011b). Cottonseed is marketed to organic dairies for feed (TOCMC 2011b). According to a 

survey conducted by OTA, organic cotton growers’ biggest barriers to planting more organic 

cotton are finding a market willing to pay the added costs of organic products, production 

challenges such as weed and insect control, and labor costs. “Growers also cited competition 

from international organic cotton producers, as well as the cost of transition to organic” (OTA 

2010).

It is not likely that organic farmers will be substantially affected by a determination of 

nonregulated status of DGT Cotton. Cotton is primarily a self-pollinated plant (OECD 2010), 

and there is no reason to suspect that the biology of DGT cotton will increase its potential to 

outcross with cotton varieties utilized in organic soybean production (USDA-APHIS, 2012d). 

As set forth in Monsanto’s Petition for Nonregulated Status, field studies of DGT cotton

reproductive biology revealed no substantial differences in factors influencing reproductive 

potential, including pollen viability, date of emergence, date of 50 percent flowering, and date 

of maturity (Monsanto, 2010). 

It is important to note that the current NOP regulations do not specify an acceptable threshold 

level for the adventitious presence of GE materials in a product labeled organic (USDA-AMS 
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2010). The unintentional presence of the products of excluded methods will not affect the 

status of an organic product or operation when the operation has not used excluded methods 

and has taken reasonable steps to avoid contact with the products of excluded methods 

(Ronald and Fouche 2006; USDA-AMS 2010). However, certain markets or contracts may 

have defined thresholds (Non-GMO Project 2012).

A determination of nonregulated status of DGT cotton is unlikely to substantially affect U.S. 

organic cotton market conditions. 

IV.G.3.d. Approval in Whole of Both DT Soybean and DGT Cotton

The difference between the No Action and the Deregulation in Whole Alternatives would be 

the gradual integration of the dicamba-tolerant event DT soybean with current glyphosatetolerant soybean systems and the dicamba and glufosinate-tolerant event DGT cotton with 

current glyphosate-tolerant cotton systems using traditional breeding techniques. On the basis 

of the above information, the Deregulation in Whole and No Action Alternatives for DT 

soybean and DGT cotton are similar regarding impacts on organic production.

IV.H. OTHER IMPACTS AND MITIGATION MEASURES

This section describes other potential impacts associated with the implementation of the 

alternatives, including unavoidable impacts; short-term versus long-term productivity of the 

environment; and irreversible/irretrievable commitment of resources. This section also 

describes potential impact mitigation measures, as applicable, beyond what is already built into 

the alternatives.

IV.H.1. Unavoidable Impacts

Unavoidable impacts are any adverse environmental effects which cannot be avoided should 

the proposal be implemented (40 CFR § 1502.16).

IV.H.1.a. Production Management

In order to generally maintain economic feasibility, soybean and cotton production practices 

require herbicide usage. As a result, herbicide application is essentially unavoidable for all of the 

alternatives. Likewise, even though the adoption of DT soybean and DGT cotton is likely to 

increase the use of conservation tillage (including strip-till) methods, some degree of tillage and 

its resulting disturbance of soil is also unavoidable.

As discussed elsewhere in this report, due to the lack of sexually compatible species with 

soybean and cotton in the areas where these crops are grown and the very low levels of pollen 

transfer from those species, gene flow from DT soybean and/or DGT cotton to other species 

is not expected. A negligible level of gene flow to other varieties of the same species may be

unavoidable but can be easily addressed with proper mitigation measures in place and existing 

technologies for removing unwanted volunteers.
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IV.H.1.b. Biological Resources

While there are many mechanisms that can mitigate the potential for the occurrence of 

herbicide resistance in weed populations, depending on applicator choices, the selection of 

herbicide-resistant weeds in certain areas of the U.S. may be unavoidable under all four 

alternatives. Selection of herbicide-resistant weeds is greatly influenced by applicator choices 

such as weed control strategies. The selection of herbicide-resistant weeds can be mitigated to 

the extent that applicator behaviors can be influenced.

Under the No Action Alternative, growers are expected to continue using glyphosate-resistant 

soybean and cotton systems, and to use other registered alternative herbicides alone or in 

combination with other herbicide-tolerant soybean or cotton varieties for targeted hard-tocontrol weeds, and/or to incorporate tillage into their practices. Under this alternative growers 

will not have the additional option of applying dicamba to soybean, or dicamba and/or

glufosinate to cotton in order to provide an additional herbicide with an alternative mode-ofaction. Thus, although the selection of herbicide-resistant weeds may be unavoidable in certain 

areas of the U.S., this impact may be expected to be mitigated in part under the deregulation 

alternatives. 

Under all scenarios, the application of non-glyphosate herbicides is expected. As discussed 

above, APHIS has no jurisdiction over risks resulting from the use of herbicides or other 

pesticides; these risks fall instead within the jurisdiction of EPA’s oversight of pesticide usage. 

See Section I.B. Potential toxic effects from these herbicides on animals are likely to be 

prevented by adherence to the EPA-mandated label conditions, which are designed to ensure 

no unreasonable adverse effects on the environment. Moreover, none of the herbicides is 

expected to pose risks of population-level effects when used within label limits. Although 

unlikely, there could be a short-term loss of groundcover for those species using soy or cotton 

fields if farmers allow the land to go fallow for a few years. Potential impacts on aquatic species 

from conventional tillage include impaired habitat conditions from soil erosion.

Under the no-action alternative, comparatively greater conventional tillage practices could result 

in decreased microbial biomass and activity.

Application of herbicides according to EPA label requirements will ensure no unreasonable 

adverse effects to plant communities at the population level in the vicinity of treated crops, but 

there is the potential for presence of herbicides in unintended areas on some occasions and at 

some locations is possible under all the alternatives. 

IV.H.1.c. Socioeconomic impacts

Under the no-action alternative soy and cotton seed growers would need to discard any DT 

soybean and DGT cotton seed grown for future expected crop production cycles. Returns to 

past investments in the development of these varieties that depend on production in the United 

States would no longer be realized. Also, soy and cotton growers and processors would not be 

able to benefit from any increased returns provided by DT soybean and DGT cotton as 

compared to alternate deregulated varieties. 
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IV.H.1.d. Physical environment

Under the no-action alternative, use of more intensive tillage practices (conventional/traditional 

tillage) by growers in certain areas in the U.S. in an attempt to manage glyphosate-resistant 

weeds would likely increase compared to practices used in planting of DT soybean and/or 

DGT cotton. Adoption of conventional tillage would be expected to result in greater soil 

erosion, loss of organic matter, soil compaction, and reduced moisture holding capacity, as 

compared to conservation or reduced tillage methods. This would lead to an increase in 

potential sedimentation and turbidity in nearby surface waters during rain and irrigation events. 

A return to more conventional tillage methods would also lead to more limited micro-organism 

diversity and possible elimination of some micro-organisms. 

As discussed above, under all alternatives, growers would be expected to apply non-glyphosate 

herbicides. As discussed above, APHIS has no jurisdiction over risks resulting from the use of 

herbicides or other pesticides; these risks fall instead within the jurisdiction of EPA’s oversight 

of pesticide usage. See Section I.B. Application of these herbicides could potentially impact 

micro-organisms in soil. This could limit micro-organism diversity or possibly eliminate some 

micro-organisms.

IV.H.1.e. Human Health

Under the no-action alternative, it is expected that the use of cultivation and other equipment 

would be greater than in the deregulation alternatives, which could increase adverse health 

effects from exposure to engine exhaust and fugitive soil particulates. Under all alternatives, 

growers would be expected to apply non-glyphosate herbicides. Workers would likely be 

exposed to a higher rate of potential equipment accidents due to the production practices 

associated with the no-action alternative, and they would be likely exposed to higher rates and 

amounts of engine emissions and soil particulates, as compared to practices used in growing 

DT soybean and DGT cotton. Also under the no-action alternative, the number of workers in 

the field would likely be greater, given the different production practices, which could increase 

the numbers exposed to equipment emissions, soil particulates, and pesticides.

IV.H.2. Short-term vs. Long-term Productivity of the Environment

Short-term uses and long-term productivity of the environment are linked, and opportunities 

that are acted upon have corollary opportunity costs in terms of foregone options and 

productivity could have continuing effects well into the future.

An issue with respect to long-term productivity is the extent to which herbicide-resistant weeds 

in certain areas of the U.S. will result from the agronomic practices related to each of the 

alternatives. These issues exist with respect to all herbicides used, including those used outside 

of glyphosate-tolerant cropping systems. That said, as glyphosate-resistant weeds have 

developed, the question of how to effectively control these weeds in glyphosate-tolerant 

cropping systems has emerged. Stacking DT soybean and/or DGT cotton with glyphosatetolerant traits, as Monsanto has indicated that it intends to do, would enable use of a 

combination of different herbicide modes of action to be applied to these crops, an approach 

that is expected to mitigate the potential for future development of herbicide-resistant weeds 

(Duke and Powles, 2009). Based on individual grower needs, this approach may reduce the 

need to use conventional tillage to control glyphosate-resistant weeds (Owen et al. 2011), which 
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could potentially lead to a reduction in crop residue and SOM (Towery and Werblow 2010). 

Increased tillage could subsequently decrease soil stability, soil structure, and infiltration and 

water holding capacity, as well as increase the potential for wind and water erosion (USDANRCS, 1996). By helping to manage glyphosate-resistant weeds in certain areas of the U.S., the 

deregulation alternatives may benefit the long-term productivity of the environment. 

In addition, Best Management Practices can help control the development of herbicide-resistant 

weeds. These include: a) identifying weeds and monitoring for escapes to determine if current 

practices need to be modified to achieve acceptable levels of weed control; b) using proper 

herbicide rates and timing; c) using crop rotation to facilitate use of different modes of action 

over time; d) using agronomic management practices to supplement herbicide weed control; e) 

alternating herbicides with different modes of action; and f) tank mixing herbicides of different 

modes of action. 

IV.H.3. Irreversible Resource Commitments

Irreversible resource commitments represent a loss of future options. It applies primarily to the 

use of nonrenewable resources and to factors that are renewable only over long time spans, or 

to adverse impacts that cannot be reversed once they are set in motion. An irretrievable

commitment of resources represents opportunities that are foregone for the period of the 

proposed action.

No irreversible or irretrievable commitments of resources were identified with respect to 

production and management of soy or cotton crops and physical environmental resources for 

any alternative. It is expected that much of the land that would be used for DT soybean and/or 

DGT cotton production under the deregulation alternatives is already in use for soy and/or 

cotton production respectively, or for other agricultural production. Land currently used for soy 

or cotton production could be allowed to go fallow or could be used for crops other than soy 

or cotton. Acreage used for soy or cotton production does not represent an irreversible or 

irretrievable commitment of resources because the land can be easily converted to serve other 

purposes such as growing other crops or for commercial or residential use. Soil used for soy 

and/or cotton production does not represent an irreversible or irretrievable commitment of 

resources because the soil composition can be amended through changes in production 

management (e.g., tillage practices, chemical application) or converted to serve other purposes 

such as growing other crops or going fallow. Surface water and groundwater used for irrigation 

purposes would be replenished through the natural water cycle as long as sustainable use of 

water resources is practiced.

IV.H.4. Mitigation Measures

As defined in the CEQ regulations for implementing NEPA (40 CFR § 1508.20) mitigation 

includes:

 avoiding the impact altogether by not taking a certain action or parts of an action;

 minimizing impacts by limiting the degree or magnitude of the action and its 

implementation;

 rectifying the impact by repairing, rehabilitating, or restoring the affected environment;
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 266 of 946

 reducing or eliminating the impact over time by preservation and maintenance 

operations during the life of the action; and

 compensating for the impact by replacing or providing substitute resources or 

environments.

The measures listed below, if employed, would mitigate possible adverse impacts that may be

associated with the deregulation alternatives. Whether these mitigation methods are required 

through a regulatory program or are used as part of industry led stewardship programs, they can 

be effective. A summary of mitigation measures are presented by resource area below. Note 

that not all mitigation measures would work for all users. The mitigation measures discussed 

below do not apply to the No Action Alternative because DT soybean and DGT cotton would 

be grown under the regulations in 7 CFR part 340. Conditions would be used to confine the 

plantings. Many of the recommendations below would be incorporated into the conditions. 

Any DT soy or DGT cotton grown under the No Action Alternative would be subject to 

conditions in the associated growing permit for the regulated biotechnology crops. The 

mitigation measures described below focus primarily on measures that are not built into the 

alternatives. 

As discussed elsewhere in this report, Congress transferred regulatory authority over herbicides 

from USDA to EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or 

herbicide resistance, and no authority to consider herbicide impacts under the PPA. 

Nonetheless, because APHIS indicated in its Notice of Intent to Prepare an Environmental 

Impact Statement (78 Fed. Reg. 28796, May 16, 2013) that it would be considering herbicide 

effects and herbicide resistance as part of the NEPA process, Monsanto has included a 

discussion of herbicide impacts in the following section. Importantly, however, Monsanto 

believes that APHIS has no legal obligation under NEPA to consider herbicide impacts or 

herbicide resistance in any Environmental Impact Statement or Environmental Assessment. 

See DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an agency has no ability to 

prevent a certain effect due to its limited statutory authority over the relevant actions, the 

agency cannot be considered a legally relevant “cause” of the effect, and is therefore not 

required to analyze the environmental impact of an action it could not refuse to perform). See

also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at *16-17 (9th 

Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not exhibit any risk of 

plant pest harm, APHIS must deregulate it since the agency does not have jurisdiction to 

regulate organisms that are not plant pests.”).

IV.H.4.a. Production Management

IV.H.4.a.(1) Measures to Mitigate Herbicide Impacts

Mitigation measures to oversee the proper usage of herbicides are determined by EPA and are 

disseminated to the herbicide users through EPA approved labels. Under the No-Action 

Alternative, glyphosate and non-glyphosate herbicides would continue to be used on soy and

cotton crops, potentially at similar levels as prior to deregulation, but more likely at greater

levels, as non-glyphosate pesticide applications are likely to increase in certain areas of the U.S. 

as efforts to control glyphosate-resistant weeds occur in such areas. Under the deregulation 

alternative, more dicamba and potentially glufosinate, but less of other herbicides, would be 

used than under the No-Action Alternative. Adhering to herbicide label requirements, including 
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application rates and other requirements, following industry stewardship programs, and U.S. 

EPA’s and the states’ overnight of pesticides will largely minimize improper herbicide usage.

IV.H.4.a.(2) Measures to Mitigate Gene Flow to Other Crops

As discussed above, soybean lacks sexually-compatible relatives in the U.S.; therefore, the only 

pollen-mediated gene flow would be within cultivated soybean. Similarly, of the two “wild”

(native) species of cotton that exist in the U.S., one cannot produce sexually fertile offspring 

when crossed with domesticated cotton, and the other is endemic to Hawaii, where 

domesticated cotton is not produced, with the exception of potential counter-season breeding 

nurseries where appropriate isolation distances and practices are utilized. As a result, gene flow 

to wild species of soy and/or cotton is not expected. 

With respect to gene flow to other domesticated populations, as discussed above, this is 

unlikely due to the biology of the soybean and cotton plants. Under the No-Action Alternative, 

there would be no further commercial release of DT soybean and DGT cotton and existing DT 

soybean and DGT cotton plants would eventually be harvested. Research and development 

permits would not be affected by this alternative. Therefore, research and development 

plantings under APHIS permits could still occur. Those plantings would be subject to the 

permit conditions, which have gene flow mitigation stipulations.

Under the deregulation alternatives, DT soybean and/or DGT cotton could be grown by 

farmers across the country. Mitigation measures to reduce the potential impact of gene flow 

include geographic separation of seed production regions and isolation distances. Specialty 

crop growers employ practices and standards for seed production, cultivation, and product 

handling and processing to ensure that their products are not pollinated by or commingled with 

other soy or cotton crops (which includes GE crops) (Bradford 2006). These management 

practices include maintaining isolation distances to prevent pollen movement from other cotton 

sources, planting border or barrier rows to intercept pollen, equipment cleaning during harvest, 

post-harvest separation of harvested seed, and employing natural barriers to pollen (Bradford 

2006; Kuepper 2006; Wozniak and Martinez 2011). These management practices allow the 

grower to meet standards for the production of specialty crop seed, maintain genetic purity, and 

protect the genetic diversity of soy and/or cotton (Bradford 2006). Similarly, seed certification 

cultivation practices commonly include recommendations for minimum isolation distances 

between various seed lines and planting border or barrier rows to prevent pollen movement 

(Hartmann et al. 1975; Wozniak and Martinez 2011). The isolation distance for Foundation, 

Registered, and Certified seeds, as dictated by the USDA Agricultural Marketing Service’s 

(AMS) Federal Seed Act, is 1,320, 1,320, and 660 feet, respectively (7 CFR Part 201.76). During 

the growing season, seed certification agencies will monitor the fields for off-types, other crops, 

weeds, and disease (Wozniak and Martinez 2011). These certifying agencies also establish seed 

handling standards to reduce the likelihood of seed source mixing during production stages, 

including planting, harvesting, transporting, storage, cleaning, and ginning (Wozniak and 

Martinez 2011). Soybean seed fields are also mapped to ensure the seed field has the minimum 

federal isolation requirement of five feet as a physical barrier (AOSCA 2009b).
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IV.H.4.a.(3) Measures to Mitigate Gene flow to Wild Soy and/or Cotton Populations

As discussed above, soybean does not grow in the wild in North America. Similarly, no feral 

species of Gossypium have been found in cotton-growing areas (Fryxell 1984; Waghmare et al. 

2005). As a result, gene flow to wild soy and/or cotton populations is not expected. 

IV.H.4.a.(4) Measures to Mitigate Volunteer DT Soybean and DGT cotton Plants

Correct application of herbicides would allow for control of volunteer DT soybean and/or 

DGT cotton plants. As discussed in Appendix A of this Environmental Report, a substantial 

number of alternative herbicides exist for the control of volunteer DT soybean and/or DGT 

cotton. 

IV.H.4.b. Biological Resources

IV.H.4.b.(1) Measures to Minimize Impacts on Animals and Non-target Plants

Mitigation measures to minimize the potential impacts on animals, micro-organisms, and nontarget plants under all of the alternatives include measures that already are a part of standard 

production practices for soybean and cotton. Complying with herbicide label instructions as 

required by EPA should minimize potential toxic effects from all alternatives. Unless EPA 

otherwise directs through the registration, Monsanto will take several steps to manage dicamba 

offsite movement including: the use of only low volatility dicamba formulations, for example

the DGA salt of dicamba; requiring growers to consult a website like Pre-Serve.org to confirm 

whether threatened or endangered species may be in proximity to the application area; and 

specifying requirements on the product label intended to reduce the potential for drift, 

including a wind-directional no-spray buffer when sensitive areas including areas where 

threatened and endangered species may be present, to ensure protection of these sensitive 

areas. These restrictions, and/or any other measures imposed by EPA, will minimize the impact 

on animals and non-target plants from the use of dicamba on DT soybean and DGT cotton.

To mitigate potential adverse effects due to herbicide drift during applications, EPA imposes 

specific application requirements on product labels. Depending upon the herbicide, relevant 

factors in managing the potential for spray drift include the selectivity and sensitivity of the 

herbicide, local weather conditions at the time of application (wind, temperature, humidity, 

inversion potential), droplet size distribution, application volume, boom height (height of the 

application equipment above the crop canopy), sprayer speed, and distance from the edge of 

the application area (Felsot et al. 2010; SDTF 1997). A variety of measures can be employed to 

control the potential for spray drift and offsite movement, including nozzle selection and 

application techniques and restrictions. Additionally, ground-based application of herbicides 

minimizes the potential for spray drift to occur. Monsanto’s proposed label for dicamba —

which is currently pending before EPA—does not allow aerial application on DT soybean or 

DGT cotton. This label restriction, and/or other measures imposed by EPA, will minimize the 

potential for spray drift. For the deregulation alternatives, conservation tillage practices likely 

associated with DT soybean and DGT cotton production maximize retention of crop residues 

and minimize soil disturbance erosion, thereby minimizing potential adverse effects on microorganisms from soil disturbance and crop residue removal, and minimizing potential adverse 

effects on aquatic plants and animals from sedimentation, turbidity, and chemical inputs from 

runoff.
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IV.H.4.b.(2) Measures to Mitigate the Evolution and Development of Resistant Weeds

Glyphosate-resistant weeds have developed in some cropping systems in certain areas of the 

U.S. The deployment of several other practices by growers, including the use of herbicides 

with different mechanisms of action and BMPs (as discussed in Section IV.H) may also help 

mitigate selection of herbicide-resistant weeds. (Norsworthy et al. 2012). The deregulation 

alternatives are expected to expand growers’ options to utilize weed control systems with 

different mechanisms of action. 

As discussed elsewhere in this report, Congress transferred regulatory authority over herbicides 

from USDA to EPA. Accordingly, USDA-APHIS has no jurisdiction over herbicides or 

herbicide resistance, and no authority to consider direct, indirect, or cumulative herbicide 

impacts under the PPA that may be associated with the deregulation and use of DT soybean or 

DGT cotton. Nonetheless, because APHIS indicated in its Notice of Intent to Prepare an 

Environmental Impact Statement (78 Fed. Reg. 28796, May 16, 2013) that it would be 

considering herbicide effects and herbicide resistance as part of the NEPA process, this 

document includes a discussion of herbicide impacts in the following sections, with more 

details in the Appendices. Importantly, however, Monsanto believes that APHIS has no legal 

obligation under NEPA to consider direct, indirect, or cumulative herbicide impacts or 

herbicide resistance in any Environmental Impact Statement or Environmental Assessment. 

See DOT v. Public Citizen, 541 U.S. 752, 770, 769 (2004) (where an agency has no ability to 

prevent a certain effect due to its limited statutory authority over the relevant actions, the 

agency cannot be considered a legally relevant “cause” of the effect, and is therefore not 

required to analyze the environmental impact of an action it could not refuse to perform). See 

also Center for Food Safety v. Vilsack, No. 12-15052, 2013 U.S. App. LEXIS 9920, at *16-17 (9th 

Cir. 2013) (“If APHIS concludes that the presumptive plant pest does not exhibit any risk of 

plant pest harm, APHIS must deregulate it since the agency does not have jurisdiction to 

regulate organisms that are not plant pests.”).

Once resistant weeds are observed, mechanisms that can help mitigate weed persistence include 

the implementation of diversified weed management systems (such as tillage) in addition to 

implementing other best management practices, such as field scouting and other management 

practices that can identify weeds that appear to have resisted the herbicide. Among growers 

there is increasing awareness of herbicide stewardship needs. Industry is providing more tools 

to help growers adopt the farming practices that will both mitigate the development of 

herbicide resistance where it exists and help control the spread of herbicide-resistant weeds. 

The likely future commercialization of DT soybean and DGT cotton varietals with stacked 

glyphosate tolerance is one such option. 

As discussed further in Appendix B, DT soybean and DGT cotton combined with glyphosatetolerant soybean and cotton will provide the tools to directly manage the development of 

dicamba-, glufosinate-, and glyphosate-resistant weeds. One of the most recommended weed 

management practices by experts is the use of multiple herbicide modes-of-action when 

appropriate. The WSSA reports: “Weed scientists know that the best defense against weed 

resistance is to proactively use a combination of agronomic practices, including the judicious 

use of herbicides with alternative modes-of-action either concurrently or sequentially” (WSSA 

2010). Studies have demonstrated that using the same combination of herbicides with multiple 

modes of action and overlapping effectiveness over multiple seasons is an effective way to 

proactively manage resistance (Beckie and Reboud 2009). In soybeans, the use of dicamba in 
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conjunction with glyphosate and other residual herbicides provides growers with an effective 

herbicide system with two to three distinct modes-of-action with activity on the major target 

weeds including biotypes with resistance to glyphosate. In cotton, the use of dicamba and 

glufosinate in conjunction with glyphosate provides growers with an effective herbicide system 

with three distinct modes-of-action.

To support the introduction of varieties containing DT soybean and DGT cotton, Monsanto 

will use multiple methods to distribute technical and stewardship information to growers, 

academics and grower advisors regarding the use of the product as part of a diversified weed 

management system. Monsanto’s Technology Use Guide (TUG), which is signed by all 

growers that utilize traits like those in DT soybean and DGT cotton, will set forth the 

requirements and best practices for the cultivation including recommendations on weed 

resistance management practices. Growers who purchase varieties containing DT soybean and 

DGT cotton will be required to enter into a limited use license with Monsanto and must sign 

and comply with the Monsanto Technology Stewardship Agreement (MTSA), which requires 

the grower to follow the TUG.

The weed resistance management practices that are designed to minimize the potential for the 

development of herbicide-resistant weeds will be articulated in the TUG and also be broadly 

communicated to growers and retailers. These practices will be communicated through a 

variety of means, including direct communications to each grower authorized to purchase and 

plant a variety containing DT soybean and DGT cotton, a public website, and reports in farm 

media publications. The overall weed resistance management program will be reinforced 

through collaborations with U.S. academics, who will provide their recommendations for 

appropriate stewardship of dicamba in soybean production and dicamba and glufosinate in 

cotton production, as well as by collaboration with crop commodity groups who have launched 

web-based weed resistance educational modules (WSSA 2012).

IV.H.4.c. Socioeconomic Impacts

No options to mitigate any socioeconomic impacts have been identified.

IV.H.4.d. Physical Environment

In general, impacts on the physical environment from soy and cotton farming, as with any crop, 

are minimized through implementation of proper management practices for each agricultural 

activity, such as tillage, erosion control, and pesticide application.

As described in Section V.A, increases in the acreage of DT soybean and/or DGT cotton are 

expected under the deregulation alternatives. To the extent they are concerns, land use-related 

impacts such as potential for gene flow can be minimized by adherence to the management 

practices and isolation distances.

Impacts on soil quality are an expected consequence of farming in general. As described in 

Section V.D, soil impacts can vary with the tillage practices in use, and can be reduced through 

increased use of conservation and reduced tillage techniques. Adoption of DT soybean and/or 

DGT cotton would facilitate increased use of conservation and reduced tillage and thus would

lead to reduced adverse impacts on soil quality.
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As described in Section II.C.3, the use of tractors and other equipment to cultivate the soil and 

conduct other activities involved with growing soybean and/or cotton can result in engine 

emissions and fugitive soil particulates being carried by the wind to the neighboring public. 

These emissions and particulates are an expected consequence of farming in general, but they 

can be reduced by changes in farming practices. Under the deregulation alternatives, there is 

evidence that the increased use of conservation and reduced tillage associated with adoption of 

DT soybean and/or DGT cotton can decrease usage of fossil fuel-burning equipment, decrease 

soil erosion by wind, and decrease pesticide usage.

As with other agricultural crops, the effects of soybean and cotton farming on surface water 

and groundwater (e.g., lakes, streams, aquifers) depend on multiple factors or activities related 

to crop production, which can include soil preparation, planting and harvesting; tillage 

practices; tractor and other equipment use; the use of herbicides and fertilizers; and the 

frequency of irrigation necessary to produce a viable crop. Under the deregulation alternatives 

and as discussed in Section II.C.1, adoption of DT soybean and/or DGT cotton facilitates 

increased use of conservation and reduced tillage practices which, compared to typical tillage 

practices for conventional soybean and/or cotton, decreases soil erosion, reduces water runoff, 

and reduces contaminant levels in runoff, all of which lead to improved surface water and 

groundwater quality.

IV.H.4.e. Human Health

For the potential adverse effects to human health from the use of pesticides that may occur 

under all of the alternatives, mitigation measures include the handling and use requirements and 

precautionary statements on pesticide labels required by EPA. Pesticide labels convey the 

necessary information developed by EPA on how to handle, store, apply, and dispose of 

pesticides with a reasonable certainty of no harm to human health. Using a pesticide in a 

manner that is inconsistent with these directions on the label is a violation of FIFRA and EPA, 

and state regulatory bodies have enforcement authority over such misuse. For the potential 

higher equipment use under the No-Action Alternative, safety labels and equipment already are 

used and no additional mitigation measures could be identified.

V. CUMULATIVE IMPACTS

This section describes potential cumulative impacts in connection with deregulating DT 

soybean and DGT cotton. Below, this section considers potential direct and indirect impacts 

of the proposed action and alternatives in combination with the potential impacts of other 

relevant past, present, and reasonably foreseeable future actions that may have an impact on the 

same resources. These combined impacts are called cumulative impacts. 

CEQ regulations (40 CFR § 1500 to 1508) that implement the procedural requirements of 

NEPA (42 U.S.C. § 4321 et seq.) require a cumulative impacts analysis of the action as part of 

the Environmental Impact Statement (EIS) process. CFR § 1508.7 defines cumulative impacts 

as:

[T]he impact on the environment which results from the

incremental impact of the action when added to other past, 

present, and reasonably foreseeable future actions regardless of

what agency (Federal or non-Federal) or person undertakes such
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other actions. Cumulative impacts can result from individually

minor but collectively significant actions taking place over a

period of time.

In this section, actions that could have effects that coincided in time and space with the effects 

from the proposed deregulation and associated activities, are identified and considered in 

combination with the impacts of other Federal, non-Federal, and private actions.

V.A. STRUCTURE OF THE CUMULATIVE IMPACTS ANALYSIS

For this report, the analysis of cumulative impacts follows the analysis steps described in 

Considering Cumulative Effects Under the National Environmental Policy Act (CEQ, 1997):

Specify the class of actions for which effects are to be analyzed.

Designate the appropriate time and space domain in which the relevant actions occur.

Identify and characterize the set of receptors to be assessed.

Determine the magnitude of effects on the receptors and whether those effects are 

accumulating.

V.B. CLASS OF ACTIONS TO BE ANALYZED

This analysis addresses large, regional, and national-scale trends and issues that have impacts 

that may accumulate with those of the Deregulation Alternative. This analysis does not 

evaluate site-specific cumulative impacts, primarily because DT soybean and DGT cotton are

grown widely and are rotated with other crops in agricultural system. The decision to be made 

by APHIS does not dictate specific locations for planting; therefore, site specific analysis is not 

possible. 

V.C. GEOGRAPHICAL AND TEMPORAL BOUNDARIES FOR THE ANALYSIS

The alternatives are discussed in Section III. For the Deregulation Alternative, Monsanto has 

requested the deregulation of DT soybean and DGT cotton without geographic restrictions. 

DT soybean and DGT cotton would be potentially cultivated throughout the continental U.S. 

Therefore, the spatial domain for past, present, and reasonably foreseeable future actions 

considers the entire nation and in some cases, has international implications. This analysis 

focuses more on geographic interaction of activities than timing of interactions because the 

actual timeframes for many of the reasonably foreseeable future actions are uncertain. 

Reasonably foreseeable actions are generally those future actions for which there is a reasonable 

expectation that the action could occur, such as a project that has already started or a future 

action that has obligated funding. Monsanto has identified activities relevant to the cumulative 

impacts analysis from reviews of information available from government agencies, such as 

Environmental Impact Statements, land-use and natural resource management plans, and from 

private organizations. Not all actions identified in this analysis would have cumulative impacts 

on all resource areas.
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V.D. RESOURCES ANALYZED

Resources evaluated in this cumulative impacts analysis include the resource areas discussed in 

Sections II and IV: Land Use and Production Practices; Physical Environment; Biological; 

Human Health and Safety; and Socioeconomic. However, as discussed in Sections II and IV,

resources that would experience impacts from the deregulation of DT soybean and DGT 

cotton in combination with other actions are described, and an analysis of the cumulative 

effects to the resource is presented below.

V.E. MAGNITUDE OF EFFECTS ON RESOURCES

The potential extent of the impacts of the deregulation alternatives combined with other 

actions, and the duration of those impacts are considered in determining the magnitude of 

cumulative effects that impact each resource area. When possible, the assessment of the effects 

on a resource is based on quantitative analysis; however, many effects are difficult to quantify. 

In these cases, a qualitative assessment of cumulative impacts is made. CEQ regulations at 40 

CFR § 1502.22—incomplete or unavailable information, directs agencies on how to proceed 

when evaluating effects on the human environment in an EIS when there is incomplete or 

unavailable information. While information describing the characteristics and potential effects 

of other projects and activities within the time and space domain is primarily qualitative and in 

some cases is incomplete or unavailable, there is enough information to consider the cumulative 

effects of the deregulation of DT soybean and DGT cotton. This qualitative approach is used 

when necessary throughout this section and for each resource area. For this section if a topic is 

discussed qualitatively, further quantitative details about the topic are either incomplete or 

unavailable.

As suggested by the CEQ (1997) handbook, Considering Cumulative Effects Under the National 

Environmental Policy Act, this report considered the following basic types of cumulative effects 

that might occur due to the deregulation alternatives:

 Additive — loss of a resource from more than one incident.

 Countervailing — adverse effects are compensated by beneficial effects.

 Synergistic — total effect is greater than the sum of effects when considered 

independently.

In the following analysis, cumulative impacts should be considered additive unless designated as 

otherwise. In the case of most resources that may experience cumulative impacts, the 

Deregulation Alternative is only responsible for a contribution of an incremental portion the 

total impact on the resource. The past, present, and reasonably foreseeable connected actions 

typically contribute to the majority of impacts experienced by the resource, and would continue 

to have impacts on the resource even if the No Action Alternative were implemented.

V.F. ASSUMPTIONS USED FOR CUMULATIVE IMPACTS ANALYSIS

As described and analyzed throughout Section V, DT soybean and DGT cotton, if deregulated, 

are not expected to have direct effects on the environment that differ from current 

commercially cultivated soybeans and cotton, because they are phenotypically, agronomically 
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and ecologically the same as current commercial cotton, except for their tolerances to dicamba 

and dicamba and glufosinate, respectively. The difference between the Deregulation in Whole 

and the No Action Alternative is expected to be integration of DT soybean and DGT cotton 

into the glyphosate-tolerant soybean cotton systems (GE-derived systems) using traditional 

breeding techniques. Therefore, the only foreseeable potential impacts are related to changes in 

weed management (herbicide use and tillage). Nevertheless, while the focus of this discussion 

is on potential cumulative impacts related to changes in weed management, it also addresses 

potential cumulative impacts related to combination of DT soybean and DGT cotton with crop 

varieties with different GE traits that are no longer subject to the regulatory requirements of 7 

CFR part 340 (i.e., “stacked” traits). 

Cumulative effects have been analyzed for each environmental issue assessed in Section V. In 

this report, the cumulative effects analysis is focused on the incremental impacts of the 

deregulation of DT soybean and/or DGT cotton taken in consideration with related activities, 

including past, present, and reasonably foreseeable future actions. Certain aspects of these 

products and their cultivation would be no different from other conventional or previously 

deregulated variants of these crops; these instances are described below. In this analysis, if there 

are no direct or indirect impacts identified, then it is assumed that there can be no cumulative 

impacts. Where it is not possible to quantify impacts, a qualitative assessment of potential 

cumulative impacts is provided. 

V.G. CONVENTIONAL BREEDING WITH OTHER GE-DERIVED OR NON-GE 

CROPS

Stacked soybean and cotton varieties may contain more than one GE trait as the result of 

crossing two GE plants. DT soybean and/or DGT cotton may be crossed with non-GE or GE 

varieties of those plants that are no longer subject to the regulatory requirements of 7 CFR part 

340 or the plant pest provisions of the Plant Protection Act. APHIS regulations at 7 CFR Part 

340 do not provide for Agency oversight of GE soybean and cotton varieties no longer subject 

to the requirement of Part 340 and the plant pest provisions of the Plant Protection Act, or 

over stacked varieties combining these GE varieties, unless it can be positively shown that such 

stacked varieties were to pose a likely plant pest risk. Monsanto has indicated that it will likely 

develop “stacked” hybrids with DT soybean and/or DGT cotton and other commercially 

available traits, expected to initially be GE glyphosate tolerance. In this process, the dicamba 

tolerance from DT soybean and the dicamba and glufosinate tolerance from DGT cotton will 

be combined with glyphosate tolerance from other varieties that are no longer subject to the 

regulatory requirements of 7 CFR part 340 or the plant pest provisions of the Plant Protection 

Act. Such a stacked variety could provide growers with the option to combine several 

herbicides with different modes of action for control of weeds. Therefore, this cumulative 

impacts analysis will assume that DT soybean and/or DGT cotton could be combined with 

commercially available glyphosate tolerant varietals as a reasonably foreseeable future action.

Deregulated GE glyphosate-tolerant (e.g., Roundup Ready®) crop varieties have been in the 

market since 1996, when glyphosate-tolerant soybean became commercially available. The 

potential effects from the cultivation of glyphosate-tolerant crops, with a corresponding 

analysis of the implications of the use of glyphosate, have been thoroughly evaluated in APHIS 

EAs since the 1993 introduction of the first glyphosate-tolerant crop product (see 

http://www.aphis.usda.gov/biotechnology/not_reg.html). 
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Several of these evaluations included crops conferring tolerance to multiple herbicides and have 

concluded there is no finding of significant impact from the deregulation in whole of the crop. 

Specific crop examples include:

 Sugar Beet, 2011. Monsanto and KWS SAAT AG Glyphosate-tolerant Sugar 

Beet (Petition No. 03-023-01p).

 Soybean, 2011. Monsanto Improved Fatty Acid Profile Soybean (which includes 

glyphosate tolerance) (Petition No. 09-201-01p).

 Alfalfa, 2011. Monsanto Glyphosate-tolerant Alfalfa (Petition 04-110-01p).

 Corn, 2009. Pioneer Glyphosate and Imadazolinone-tolerant Corn (Petition 07-

152-01p).

 Cotton, 2009. Bayer Crop Science Glyphosate-tolerant Cotton (Petition 06-332-

01p).

 Soybean, 2008. Pioneer Glyphosate and Acetolactate Synthase-tolerant Soybean 

(Petition No. 06-271-01p).

 Soybean, 2007. Monsanto Glyphosate-tolerant Soybean (Petition 06-178-01p).

 Cotton, 2005. Monsanto Glyphosate-tolerant Cotton (Petition 04-086-01p).

 Rapeseed 2001. Monsanto Glyphosate-tolerant Rapeseed (Petition 01-324-01p).

 Corn, 2000. Monsanto Glyphosate-tolerant Corn (Petitions No. 97-099-01p and 

00-011-01p).

 Rapeseed 1998. Monsanto Glyphosate-tolerant Rapeseed (Petition 98-216-01p).

 Sugar Beet, 1998. Novartis Seeds and Monsanto Glyphosate-tolerant Sugar Beet 

(Petition No. 98-173-01p).

 Corn, 1997. Monsanto Glyphosate-tolerant Corn (Petition No. 97-099-01p).

 Corn, 1996. Monsanto Glyphosate-tolerant and European Corn Borer-resistant 

Corn (Petition No. 96-317-01p).

 Cotton, 1995. Monsanto Glyphosate-tolerant Cotton (Petition 95-045-01p).

 Soybean, 1993. Monsanto Glyphosate-tolerant Soybean (Petition 93-258-01p).

The first glyphosate-tolerant soybean became commercially available to growers in 1996 after 

Monsanto’s Roundup Ready® Soybean (GTS 40-3-2) was determined to be no longer subject 

to the regulatory requirements of 7 CFR part 340 or the plant pest provisions of the Plant 

Protection Act (see APHIS Petition File 93-258-01p at 
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http://www.aphis.usda.gov/biotechnology/not_reg.html). Similarly, the first glyphosatetolerant cotton to be deregulated by APHIS was Roundup Ready® cotton lines 1445 and 1698, 

which were submitted as Petition 95-045-01p by Monsanto and deregulated by APHIS in July, 

1995.

Other stacked varieties of either of these crops might also be developed at a later time which 

also derive tolerance to dicamba from the DT soybean or to dicamba and glufosinate from 

DGT cotton. Currently, all GE soybean varieties are herbicide-tolerant, namely to glyphosate, 

with a smaller (i.e., approximately 1.3% of planted acres in 2011) but growing number of 

glufosinate-tolerant varieties available since 2010. In addition to tolerance to glyphosate and 

glufosinate, other GE soybean traits no longer subject to the regulatory requirements of 7 CFR 

part 340 or the plant pest provisions of the Plant Protection Act include lepidopteran 

resistance, high oleic acid content, and acetolactate synthase tolerance (see 

http://www.aphis.usda.gov/biotechnology/not_reg.html). Similarly, other GE cotton traits no 

longer subject to the regulatory requirements of 7 CFR part 340 or the plant pest provisions of 

the Plant Protection Act include lepidopteran resistance, glufosinate tolerance, and 

phosphinothricin tolerance. Issues associated with potential future stacking, particularly 

cultivation of a stacked hybrid incorporating glyphosate resistance from varieties previously 

determined to be nonregulated, are presented and discussed in the cumulative effects analyses 

where appropriate.

APHIS has determined that none of the individual biotechnology-derived products it has 

previously deregulated displays increased plant pest characteristics or creates potentially 

significant impacts on the human environment. APHIS has also concluded that any progeny 

derived from crosses of these deregulated biotechnology-derived soybean products with 

conventional or previously deregulated biotechnology-derived soybean are unlikely to exhibit 

new plant pest properties. This presumption that combined trait biotechnology products are 

unlikely to exhibit new characteristics that would pose new plant pest risks or potential 

environmental impacts not observed in the single event biotech product is based upon several 

facts, including: 1) stability of the genetic inserts is confirmed in each single event product 

across multiple generations; 2) stability of each of the introduced traits is continually and 

repeatedly assessed as new combined trait varieties are created by plant breeders and tested over 

multiple seasons prior to commercial release; 3) combined trait products are developed using 

the well established process of conventional breeding that has been safely used for thousands 

of years to generate new varieties; and 4) in both principle and practical application in the field, 

it has been shown that two unrelated biotechnology traits combined together by conventional 

breeding, do not display new characteristics or properties distinct from those present in the 

single event biotech products. (Brookes and Barfoot 2012; James 2010; Lemaux 2008; 

Pilacinski, et al. 2011).

V.H. DEMONSTRATED GENETIC AND PHENOTYPIC STABILITY

An assessment of the stability of the genetic inserts in DT soybean and DGT cotton are 

discussed in Appendix G to this environmental report and are summarized here; refer to the 

Appendix for more detail. Generational stability analysis was assessed by Southern blot analysis 

and demonstrated that the genetic inserts present in DT soybean and DGT cotton were

maintained across the five breeding generations evaluated. These data demonstrate that DT 

soybean and DGT cotton are stable in their progeny. Having established that the genetic 

material is stable and inherited in a Mendelian fashion, and based on experience with DT 
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soybean and DGT cotton in Monsanto’s plant breeding program over the course of many 

generations, it is concluded that the phenotypes of DT soybean and DGT cotton are likewise 

stable. There are numerous examples in the literature that confirm that GE events and their 

associated phenotypes and overall characteristics are stably inherited across generations and 

across genetic backgrounds, including when they are combined by conventional breeding to 

produce combined trait products (McCann, et al. 2005; Ridley, et al. 2011; Zhou, et al. 2011). 

V.I. COMBINED TRAIT PRODUCT PERFORMANCE IN PRINCIPLE AND IN 

PRACTICE

Conventional plant breeding is routinely used to improve crop performance and is specifically 

employed to develop plant varieties that fit particular environments and production practices 

(Powell et al., 2003). The same biological and selective principles used for conventional and 

single GE event variety development are used to combine previously approved GE events. 

When conventional breeding is used to generate varieties with combined GE events, these 

varieties are screened over multiple generations and across diverse growing environments. 

Typically, product performance and agronomic features are evaluated and crop characteristics 

such as yield, field performance, and disease resistance are measured and tested to ensure that 

the traits are stable, heritable, and express the desired phenotype under a wide range of 

environmental conditions. The phenotypic characteristics evaluated during the screening of 

new combined GE event candidate varieties are the result of the plant’s genotype and are the 

culmination of the complex metabolic pathways that are activated in response to environmental 

conditions. The evaluation of phenotypic characteristics allows breeders to assess and screen 

for potential unintended effects produced as a result of the various traits (both GE traits and 

other inherent traits) combined in the variety. Selection during the conventional breeding 

process is valuable in removing undesirable characteristics and thereby helps to maintain the 

safety and quality of the food and/or feed product (Cellini et al., 2004; NRC, 2004; WHO, 

1995).

When assessing the safety of combined GE events, it is important to consider international 

guidance regarding conventional breeding and assessments of the substantial equivalence of GE 

events combined by conventional breeding. For example, the World Health Organization 

concludes that a substantial equivalence conclusion can be maintained in a combined GE trait 

variety if substantial equivalence had been demonstrated for each of the single event parents. 

Specifically, they argue that ‘‘...if substantial equivalence has been demonstrated both for a 

[genetically engineered] tomato with a gene producing a delayed ripening phenotype and for a 

[genetically engineered] tomato with a gene for herbicide resistance, then crossing these two 

varieties would result in a new variety that would be expected to be substantially equivalent to 

the parents’’ (WHO, 1995). Additional international groups, including the Food and Agriculture 

Organization/World Health Organization (FAO, 1996), International Seed Federation (ISF, 

2005), and CropLife International (CLI, 2005) similarly advocate basing the safety of combined 

GE events on the safety of the parental GE events. The FDA has stated that ‘‘narrow crosses 

are unlikely to result in unintended changes to foods that raise safety or other regulatory 

questions’’ – ‘‘including narrow crosses between different rDNA-modified [GE] lines’’ (U.S. 

FDA, 2001).

Thus, the data packages that are developed for single GE events are useful in establishing the 

safety of the combined GE event product. Accordingly, single GE events previously assessed 

to be as safe as their conventional counterparts should continue to be safe when combined 
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through conventional plant breeding. As a result, the rigorous safety assessments and plant 

pest risk assessments conducted on single GE events, which were deemed to pose no more risk 

than their conventional counterparts, also can be used to predict the safety and potential risk of 

the combined GE event product. As described below, this assertion is supported by direct 

experience gained through the commercial planting and utilization of combined GE event 

products as well as a body of information collected to support authorizations where combined 

GE event products require additional assessment. 

There are many examples of combined trait biotech products that have been produced 

commercially on millions of acres without incident over the past decade in both the US and in 

other countries60. In the US, there are over 30 combined trait products that have been made 

commercially available. In 2011, 49% of the total corn acres planted (92 M acres) and 58% of 

total cotton planted (13M acres) contained multiple (2 or more) GE events (USDA-ERS, 

2011).

61

 Combined trait biotech products were planted on 40 million hectares or 25% of the 

global biotech area of 160 million hectares in 2011.

62

 The safety of commercially available 

combined trait biotech products has been well-demonstrated in multiple independent reports 

that document the continually increasing acceptance and use of these products by farmers 

globally (Brookes and Barfoot, 2009; James, 2009; Lemaux, 2008; Sankula, 2006). 

In addition, regulatory agencies in some countries request additional characterization of 

combined GE events and comparisons to single event parental controls and conventional 

comparators. These additional studies may include analysis of phenotype, molecular 

characteristics, protein characteristics, morphology and compositional evaluation. Analyses of 

combined GE events compared to parental controls have consistently revealed the following: 

no phenotypic differences from parental events; molecular characteristics that are the same as 

parental events with all events inherited stably; levels of introduced proteins comparable to the 

single event parents; no morphological differences compared to parental events; compositional 

equivalence based on nutrient and anti-nutrient evaluations, and no pleiotropic or toxic effects 

compared to the conventional non-GE crop (Pilacinski et al., 2011).

V.J. CUMULATIVE IMPACTS: ACREAGE AND AREA OF SOYBEAN AND 

COTTON PRODUCTION

Cumulative effects associated with a determination of nonregulated status of DT soybean to 

acreage and areas of soybean production are unlikely. Deregulation is not expected to directly 

cause a change in agricultural acreage devoted to conventional or GE soybean cultivation in the 

U.S. and there are no anticipated changes to the availability of GE and non-GE soybean 

varieties on the market. The potential future development and cultivation of a stacked soybean 

variety presenting tolerance to dicamba and glyphosate is not likely to change the current 

number of acres of soybean being treated with glyphosate, since currently more than 90% of 

 

60 See http://www.biotradestatus.com for list of combined trait products that have previously been commercialized. 

61 See http://www.ers.usda.gov/data/biotechcrops/adoption.htm.

62 http://www.isaaa.org/resources/publications/briefs/43/executivesummary/default.asp
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 279 of 946

soybean acres are planted with GE glyphosate-tolerant soybeans (USDA-ERS, 2011b). Rather, 

DT soybean is anticipated to be adopted by growers already using a GE variety, but who are 

interested in utilizing an herbicide with a different mode-of-action, either to control existing 

herbicide-resistant weeds, or to mitigate the potential for future development of herbicideresistant weeds. Additionally, the availability of a stacked variety of DT soybean for 

commercial production is not expected to change the areas where soybean can be grown for 

soybean production in the U.S. since the agronomic characteristics of DT soybean are 

essentially indistinguishable from other available soybean varieties. 

Similarly, cumulative effects associated with a determination of nonregulated status of DGT 

cotton to acreage and areas of cotton production are unlikely. Deregulation is not expected to 

directly cause a change in agricultural acreage devoted to conventional or GE cotton cultivation 

in the U.S. and there are no anticipated changes to the availability of GE and non-GE cotton 

varieties on the market. Rather, DGT cotton is anticipated to be adopted by growers already 

using a GE variety, but who are interested in utilizing an herbicide with a different mode-ofaction, either to control existing herbicide-resistant weeds, or to mitigate the potential for future 

development of herbicide-resistant weeds. The potential future development and cultivation of 

a stacked cotton variety presenting tolerance to dicamba, glufosinate, and glyphosate is similarly 

not likely to change the areas where cotton can be grown for cotton production in the U.S. 

since the agronomic characteristics of DGT cotton are essentially indistinguishable from other 

available cotton varieties. Although total U.S. cotton acreage since 2000 has varied from 

approximately 9 to 16 million planted acres, the variations observed in cotton acreage and 

production are primarily driven by current market conditions, rather than agronomic 

considerations. 

For these reasons, there are no past, present, or reasonably foreseeable actions that would 

aggregate with effects of the proposed action to impact soybean and cotton acreage and areas 

of production.

V.J.1. Cumulative Impacts: Agronomic Practices

A determination of nonregulated status of DT soybean and/or DGT cotton is not expected to 

result in changes in the current soybean and cotton cropping practices, with the exception of 

potential changes in the use of certain herbicides. As discussed above, potential impacts from 

changes to herbicide usage are addressed herein even though such impacts are outside the 

scope of APHIS’s action and fall instead within the jurisdiction of EPA’s oversight of pesticide 

usage. 

V.J.2. Soybean

DT soybean would provide soybean growers with the option to use dicamba post-emergence. 

Similar to the current use of dicamba, the use of dicamba on soybean would be in accordance 

with the per application and per year rates approved by EPA. Studies conducted by Monsanto 

demonstrate that, in terms of agronomic characteristics and cultivation practices, DT soybean is 

essentially indistinguishable from other soybean varieties currently grown. Consequently, 

impacts to cropping practices associated with the adoption of DT soybean are not expected.

Monsanto has indicated its intention to develop a stacked hybrid with DT soybean and 

commercially available soybean varieties conferring glyphosate tolerance. If combined with a 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 280 of 946

glyphosate tolerance trait, DT soybean would enable growers to use a combination of 

herbicides with different modes of action on soybean, an approach proposed to mitigate the 

future development of herbicide-resistant weeds (Duke and Powles, 2009). The future 

development and cultivation of a stacked DT soybean variety presenting the additional 

tolerance to glyphosate is not likely to increase the number of acres of soybean being treated 

with glyphosate, since, in 2011, more than 90% of soybean acres were planted with GE 

glyphosate-tolerant soybeans (USDA-ERS, 2011b). DT soybean, either alone or combined with 

other traits, would likely replace these other GE herbicide-tolerant soybeans currently being 

cultivated. Therefore, it is expected that combining other herbicide tolerance traits with those 

of DT soybean would not increase the overall number of acres that herbicide would be applied 

to. Herbicide use would be in accordance with per application and per year rates approved by 

EPA. 

V.J.3. Cotton

A determination of nonregulated status of DGT cotton is not expected to result in changes in 

the current cotton cropping practices, with the exception of potential changes in the use of 

certain herbicides. 

DGT cotton would provide cotton growers with the option to use dicamba post-emergence in 

addition to using glufosinate, which would provide different modes of action to control 

glyphosate-resistant weeds. Similar to the current use of dicamba and glufosinate, the use of 

dicamba and glufosinate on cotton would be in accordance with the per application and per 

year rates approved by EPA. Studies conducted by Monsanto demonstrate that, in terms of 

agronomic characteristics and cultivation practices, DGT cotton is essentially indistinguishable 

from other cotton varieties currently grown. Consequently, impacts to cropping practices 

associated with the adoption of DGT cotton are not expected.

Monsanto has indicated its intention to develop a stacked hybrid with DGT cotton and 

commercially available cotton varieties conferring glyphosate tolerance. If combined with a 

glyphosate tolerance trait, DGT cotton would enable growers to use a combination of 

herbicides with different modes of action on cotton, an approach proposed to mitigate the 

future development of herbicide-resistant weeds (Duke and Powles, 2009). The future 

development and cultivation of a stacked DGT cotton variety presenting the additional 

tolerance to glyphosate is not likely to increase the number of acres of cotton being treated with 

glyphosate. Glyphosate is the most widely used herbicide in cotton, applied on 91% of cotton 

acres with an average of 2.4 applications per growing season (Monsanto 2012). Therefore, it is 

expected that combining other herbicide tolerance traits with those of DGT cotton would not 

increase the overall number of acres to which herbicides would be applied. Herbicide use 

would be in accordance with per application and per year rates approved by EPA. 

V.J.4. Cumulative Impacts of Herbicides

Based on the dicamba applications and use rate analysis discussed in Appendix A to this 

Environmental Report, use of DGT cotton on 50% of U.S. cotton acres would result in 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 281 of 946

approximately 5.2 million lbs a.e. of dicamba applied to DGT cotton annually (including 

preplant, preemergence and in-crop applications). With respect to DT soybean, Monsanto 

estimates a potential increased use of dicamba by approximately 20.5 million pounds annually. 

Considering the adoption rates of DGT cotton (50%) and DT soybean (40%)63 and the current 

use of 3.8 million lbs of dicamba per year, the total U.S. dicamba use would be 

approximately29.5 million pounds annually. This level of dicamba use would be approximately 

3 times the historical peak levels experienced since dicamba’s introduction in 1967. See 

Appendix A to this Environmental Report for additional details on projected dicamba use on 

DT soybean and DGT cotton. 

However, dicamba (and glufosinate, in the case of cotton) are expected to replace the use of 

other herbicides in soybeans and cotton, such as fluometuron, fomesafen, MSMA, and 

paraquat. See Appendix A for a more comprehensive list of herbicides dicamba is expected to 

replace. The commercialization of soybean and cotton products containing dicamba-tolerance 

will allow for an increase in the use of dicamba for weed control in soybean and cotton due to 

the elimination of in-crop (POST segment) and preplant (PRE segment) crop safety concerns. 

With crop safety no longer a barrier, farmers will be able to incorporate dicamba into their 

weed management programs because of the advantages it offers versus other herbicides. The 

following are some of the most significant advantages dicamba offers over other alternative 

herbicides: 

 Improved efficacy compared to other commercially available herbicides to 

control tough broadleaf weeds and weeds that are resistant to glyphosate and 

other herbicides used in soybean and production (Johnson et al., 2010)

 Greater convenience and flexibility due to the elimination of plant back and 

rotational crop restrictions

 Improved crop safety relative to other herbicide options

 Reduced handling restrictions relative to other herbicide options

 A more benign toxicity profile and lower risk potential to applicators, 

consumers, and aquatic organisms compared to some alternative herbicides 

(Appendix A).64

These advantages will translate into dicamba replacing certain non-glyphosate herbicides 

currently used preplant and/or postemergent in soybeans and cotton. In addition, the ability to 

use dicamba to manage existing resistant weeds will drive an overall reduction in herbicide use 

in some situations. For example, Monsanto and academics currently recommend that farmers 

with glyphosate resistant weeds apply a residual product, such as flumioxazin, or fomesafen 

preplant to the crop, followed by fluometuron preemergence, and followed by glyphosate plus 

 

63 Monsanto projects dicamba to be conservatively used on 40% of U.S. soybean acres. This estimate was incorrectly listed 

as 50% in Tables VIII-21 through VIII-24 in petition 12-185-01p_a1.

64 In order to approve a new use of a herbicide EPA must conclude that the herbicide, when used according to the label, 

does not pose an unreasonable adverse effect to humans or the environment, and, in order to establish a tolerance for the 

use of a herbicide on a food or feed crop, find there is a reasonable certainty of no harm to human health from nonoccupational (food, water and residential/recreational) exposures to the herbicide. Therefore, all alternative herbicides 

used in cotton production can be used safely, and do not pose an unreasonable risk to humans or the environment.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 282 of 946

acetochlor or metolachlor after planting, and then conclude with hooded applications of 

paraquat and/or directed applications of MSMA or diruon to control escapes.65 With the ability 

of farmers to use dicamba in crop, dicamba would replace the need for some of these products, 

and others currently being used, thus resulting in a shift and replacement of herbicide use and 

applications. Monsanto will continue to recommend the use of multiple herbicide modes-ofaction in the dicamba systems, including residual herbicide products.

Glyphosate is not expected to be replaced by dicamba in either the PRE or the POST segment. 

Dicamba will primarily be used in combination with glyphosate and this combination will 

simply displace glyphosate combinations with other non-glyphosate herbicides and/or 

glyphosate herbicide used alone. 

With respect to soybeans, the projected total pounds of herbicides in each application segment 

(PRE and POST) that would be replaced by dicamba were determined using the methodology 

and data source as the total area treated (TAT) analysis described in Appendix A. The same 

herbicide growth projections for the PRE and POST application segments (i.e., 101% and 

132%) were applied to the 2011 pounds of herbicide applied data. Based on this analysis, we 

project that dicamba would replace an estimated 3.6 million pounds of PRE non-glyphosate 

herbicides and 1.6 million pounds of POST non-glyphosate herbicides in 2015 (See Appendix 

A to this Environmental Report). 

With respect to cotton, the projected total pounds of herbicides in each application segment 

(PRE and POST) that would be replaced by dicamba were determined using the methodology 

and data source as used in the TAT analysis described in Appendix A. Based on this analysis, 

we project that dicamba would replace an estimated 1.35 million lbs of PRE non-glyphosate 

herbicides and 0.5 million lbs of POST non-glyphosate herbicides at peak market penetration. 

See Appendix A to this Environmental Report for details on DT soybean and DGT cotton 

herbicide use analysis.

V.K. NET IMPACT OF DT SOYBEAN AND DGT COTTON ON OVERALL 

HERBICIDE USE

The analysis set forth above and described in great detail in Appendix A, was completed to 

evaluate the assertions made in recent publications by Benbrook (2012) and Mortensen et al. 

(2012), which suggest the commercialization of dicamba-tolerant soybeans and associated use 

of dicamba will only be additive to current herbicide use and, according to Mortensen, could 

result in a ‘profound’ increase in overall herbicide use. The main reasons for their conclusions 

are (1) overall herbicide use in 2007 was projected to not change through 2013, and (2) dicamba 

use would be entirely additive to use of existing herbicides. However, the analysis above and in 

Appendix A highlight the inaccuracy of these conclusions and clearly demonstrates two key 

conclusions:

 

65 www.roundupreadyplus.com. Warrant is a trademark of Monsanto Technology LLC. All other trademarks are the 

property of their respective owners.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 283 of 946

(1) The overall use of non-glyphosate herbicides in soybean and cotton production has grown 

since 2007, and this growth is expected to continue and eventually plateau. The current and 

projected future growth is due in large part to the adoption of best management practices as 

recommended by public and private sector weed scientists and the development of weed 

resistance in certain areas of the U.S. This increase in non-glyphosate herbicide use would 

occur regardless of the commercialization of dicamba-tolerant soybeans and cotton, and 

(2) When dicamba-tolerant soybean and cotton systems are available, dicamba would displace a 

significant amount of non-glyphosate herbicides used for weed management. Based on 

expectations by Monsanto and academic weed scientists that farmers will continue to 

implement diversified weed management programs that utilize multiple herbicide modes-ofaction and dicamba would be an important weed management tool in future soybean and 

cotton production.

The deregulation and subsequent commercialization of dicamba-tolerant soybean and cotton 

will not alter the number of cultivated soybean or cotton acres or the geographical areas where 

soybean and cotton are cultivated in the U.S. Consequently, dicamba-tolerant soybeans and 

cotton will be grown on land that is already highly managed for agricultural crop production 

and where herbicides are widely used today. As described previously, the commercialization of 

dicamba-tolerant soybeans and cotton will result in a slight increase in herbicide use (treated 

acres and pounds of dicamba) on those acres where it is planted and the grower chooses to use 

dicamba in their weed management program. However the increase in dicamba relative to 

overall herbicide use in soybean and cotton production is relatively low, contributing less than 

15% to the overall herbicide use in glyphosate-tolerant soybean production and 16 % to the 

overall herbicide use in glyphosate-tolerant cotton production. 

While an increase in overall herbicide use in soybean and cotton growing areas is projected for 

the commercialization of DT soybean and DGT cotton, assuming growers adopt 

recommended weed management practices, these practices provide numerous economic and 

environmental benefits, which are detailed in Appendices A & B and summarized below.

 Effective tool for sustainable management of glyphosate resistant weeds where 

they exist

 Mitigate the evolution and development of weed resistance for all classes of 

herbicides used in soybean and cotton production

 Improved consistency of hard-to-control weeds thereby reducing the potential 

for new resistant biotypes to develop

 Increased application flexibility 

 Preserve the benefits of the glyphosate-tolerant weed control system

 Preserve the many environmental and economic benefits of conservation tillage 

Furthermore, the projected increase in the amount of dicamba used in soybean and cotton 

production is not expected to result in adverse impacts to human health or the environment. 

The U.S. EPA regulates pesticide use and under FIFRA must reach a conclusion of no 

unreasonable adverse effects to human health and the environment before dicamba can be 

approved for use with DT soybean and/or DGT cotton. Monsanto has submitted an 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 284 of 946

application to EPA to approve the use of dicamba with DT soybean and DGT cotton. EPA 

concluded in the dicamba Reregistration Eligibility Decision document that all then-registered 

uses of dicamba can be used without resulting in unreasonable adverse effects (U.S. EPA, 

2009). Because the use patterns for dicamba with DT soybean and DGT cotton are consistent 

with the use patterns and assumptions on herbicide use intensification evaluated in the RED, 

any projected increase in dicamba use from the commercialization of DT soybean and DGT 

cotton is not expected to result in potential adverse impacts to the human health or the 

environment, and EPA will reconfirm that dicamba’s use does not result in unreasonable 

adverse effects as part of its review of the Monsanto application.

Due to the overlap of areas planted to cotton and soybeans there is the possibility for a crop 

rotation that includes both DT soy and DGT cotton. While this will increase selection pressure 

on dicamba the risk of resistance to dicamba will be effectively mitigated by the implementation 

of diversified weed management programs in both DT soy and DGT cotton. Field studies by 

Beckie and Reboud, 2009 and modeling studies by Neve et. al. (2011) both clearly demonstrate 

the effectiveness of repeated applications of the same herbicide or combinations of herbicides 

to retard the evolution of resistance when used in diversified weed management programs. In 

the case of both DT soy and DGT cotton, dicamba will be used in combinations with residual 

herbicides that are effective on targeted glyphosate resistant species and with glyphosate and/or 

glufosinate both of which would add an additional herbicide mode-of-action to control of 

certain weeds common in each crop.

Based on EPA’s assessment, adverse impacts from cumulative effects of herbicide use are not 

expected under the Deregulation in Whole Alternative.

V.L. CUMULATIVE IMPACTS: SEED PRODUCTION

Based on current trends, GE products are likely to continue to dominate soybean and cotton 

production. GE soybean varieties were grown on more than 93% of soybean acres in 2011 

(USDA-ERS, 2011b). Similarly, GE cotton lines are grown on approximately 90% of U.S. 

cotton acres. To the extent that growers see value in the traits offered by stacked DT soybean 

or stacked DGT cotton varieties, these varieties may replace existing soybean and cotton 

varieties. The availability of stacked DT soybean and DGT cotton are not anticipated to change 

cultivation areas for soybean and cotton production in the U.S. Because changes in the 

agronomic practices and locations for soybean and cotton seed production are not expected, 

there are no cumulative effects identified for either GE or non-GE seed production with the 

potential commercial availability of stacked DT soybean or DGT cotton. 

V.M. CUMULATIVE IMPACTS: ORGANIC PRODUCTION

A determination of nonregulated status of DT soybean and/or DGT cotton is not expected to 

change the market demands for GE soybean and cotton or soybean and cotton produced using 

organic methods. Data from USDA-ERS indicates that in 2011, 93% of all soybean grown in 

the U.S. were GE varieties (USDA-ERS, 2011b). GE cotton lines are grown on approximately 

90% of U.S. cotton acres. In 2008, organic soybean varieties were grown on less than 1% of the 

75.2 million acres planted with soybean in the U.S. (USDA-ERS, 2010b), and organic cotton 

was grown on approximately 0.16% of the total 9.41 million acres planted with cotton (USDAERS 2008). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 285 of 946

Based upon information on recent trends, adding GE varieties to the market is not related to 

the ability of organic production systems to maintain their market share. Since 1994, fourteen 

GE soybean events or lines and fifteen GE cotton events or lines have been determined by 

APHIS to be no longer subject to the regulatory requirements of 7 CFR part 340 or the plant 

pest provisions of the Plant Protection Act. Organic production of soybeans grew from 82,143 

acres in 1997 to a maximum of 174,467 acres in 2001. Since 2001, the total acreage of organic 

soybean production has experienced a slight decline in growth over time, with 125,621 acres 

planted in 2008 (USDA-ERS, 2010b). The decline of organic soybean acreage has been 

attributed to high prices being paid for conventional soybean and high fuel costs (McBride and 

Greene, 2008) and not the adoption rate of GE soybean. Organic cotton production has 

similarly maintained its market share. Based on USDA-ERS data, between 1997 and 2008, 

organic cotton acreage ranged from 9,213 acres in 2004 to a maximum of 15,377 acres in 2008

(USDA-ERS 2008). Based on the trends in the cultivation of GE, non-GE, and organic 

varieties, and the fact that the pressures on the corresponding production systems to maintain 

varietal integrity are likely to remain the same, there are no cumulative impacts to organic 

soybean and cotton production from a determination of nonregulated status of DT soybean 

and DGT cotton. 

V.N. CUMULATIVE IMPACTS: SOIL QUALITY

No negative cumulative effects on soil quality have been identified associated with a 

determination of nonregulated status of DT soybean and/or DGT cotton. A determination of 

nonregulated status for DT soybean and/or DGT cotton would not change agronomic 

practices affecting the quality of soil cultivated in commercial soybean and/or cotton 

production. DT soybean and DGT cotton are not expected to result in changes in the current 

soybean or cotton cropping practices, with the exception of potential changes in the use of 

certain herbicides for weed management, and a potential decrease in conventional tillage 

practices. As discussed above, potential impacts from changes to herbicide usage are outside 

the scope of APHIS’s action and fall instead within the jurisdiction of EPA’s oversight of 

pesticide usage. See Section I.B. 

If DT soybean and/or DGT cotton became commercially available and were stacked with 

other transgenic herbicide-tolerance traits, depending on the extent of adoption, they may 

contribute to sustaining conservation tillage in U.S. soybean and cotton production that both 

directly and indirectly impacts soil quality. The single most damaging effect on land due to 

agriculture is loss of soil caused by tillage. Tillage is primarily performed for seed bed 

preparation and has the added benefit as a weed control measure. Herbicide-tolerant crops 

have enabled significant implementation/adoption of no-till or reduced tillage methods for 

weed control (Duke and Powles 2009). As discussed in Section II.B.2.c, increases in total acres 

dedicated to conservation tillage have been attributed to an increased use of herbicide-tolerant 

cotton, which reduces the need for mechanical weed control (McClelland et al. 2000; Towery 

and Werblow 2010). DT soybean and DGT cotton would allow the additional use of dicamba 

and glufosinate herbicides in case of DGT cotton, in a diversified weed management program 

to control a broad spectrum of grasses and broadleaf weed species. As such, the availability of 

DT soybean and DGT cotton could help preserve the current acreage of cotton grown using 

conservation tillage and potentially help increase conservation tillage acreage. The Deregulation 

in Whole Alternative would provide another herbicide-tolerant crop option and thus could help 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 286 of 946

continued adoption and preservation of conservation tillage methods, resulting in a small 

positive cumulative environmental impact. 

As discussed above, use of herbicides alone or stacked with other herbicide-tolerant or other 

traits is not expected to increase the overall number of acres to which herbicide would be 

applied. See Sections V.A.2 and V.A.3. The total amount of the mix of herbicides that may be 

applied to DT soybean and/or DGT cotton or subsequent varieties derived therefrom would 

be used in accordance with per application and per year rates approved by EPA. EPA’s 

reregistration and registration review process ensures that each registered pesticide continues to 

meet the FIFRA registration standard, i.e., that pesticides will not cause unreasonable adverse 

effects when used as directed on product labels.

Based on the above information, there are no past, present, or reasonably foreseeable actions 

that would aggregate with effects of deregulation that would have a negative impact on soil 

resources; rather, there may be slight beneficial cumulative impacts to soil quality from 

sustaining conservation tillage rates in soybean and cotton production.

V.O. CUMULATIVE IMPACTS: WATER RESOURCES

A determination of nonregulated status of DT soybean and/or DGT cotton is not expected to 

result in changes in the current cropping practices, with the exception of potential changes in 

the use of certain herbicides, and, as discussed above, a potential decrease in conventional

tillage practices. As discussed above, potential impacts from changes to herbicide usage are 

outside the scope of APHIS’s action and fall instead within the jurisdiction of EPA’s oversight 

of pesticide usage. See Section I.B. No changes in water use or irrigation practices currently 

used in commercial soybean or cotton production are expected.

Monsanto has indicated its intention to stack DT soybean and/or DGT cotton with other 

nonregulated soy and cotton varieties, particularly varieties conferring tolerance to the herbicide 

glyphosate. Some glyphosate-tolerant crops have had nonregulated status since 1994 when 

glyphosate-tolerant soybean was determined to be no longer subject to the regulatory 

requirements of 7 CFR part 340 or the plant pest provisions of the Plant Protection Act (see 

http://www.aphis.usda.gov/biotechnology/not_reg.html) (USDA-APHIS, 1994). As discussed 

above, use of herbicides with DT soybean and/or DGT cotton alone or if stacked with other 

herbicide-tolerant or other traits is not expected to increase the overall number of acres to 

which herbicide would be applied. See Sections V.A.2 and V.A.3.

If DT soybean and/or DGT cotton became commercially available and were stacked with 

other transgenic herbicide-tolerance traits, depending on the extent of adoption, they may 

contribute to sustaining conservation tillage in U.S. soybean and cotton production that 

indirectly impacts water quality from soil erosion. The single most damaging effect on water 

quality due to agriculture is increased sedimentation and turbidity caused from erosion caused 

by tillage. Tillage is primarily performed for seed bed preparation and has the added benefit as 

a weed control measure. Herbicide-tolerant crops have enabled significant 

implementation/adoption of no-till or reduced tillage methods for weed control (Duke and 

Powles 2009). As discussed in Section II.B.2.c, increases in total acres dedicated to 

conservation tillage have been attributed to an increased use of herbicide-tolerant cotton, which 

reduces the need for mechanical weed control (McClelland et al. 2000; Towery and Werblow 

2010). DT soybean and DGT cotton would allow the additional use of dicamba, and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 287 of 946

glufosinate herbicides in case of DGT cotton, in a diversified weed management program to 

control a broad spectrum of grasses and broadleaf weed species. As such, the availability of DT 

soybean and DGT cotton could help preserve the current acreage of soybean and cotton grown 

using conservation tillage and potentially help increase conservation tillage acreage. Further, 

based on individual grower needs, this approach may reduce the need to use conventional

tillage to control glyphosate-resistant weeds (Owen, 2011), which could potentially lead to 

increased sedimentation and agricultural chemical pollutant offloading to surface water from 

soil erosion (Towery and Werblow, 2010). As a result, the Deregulation in Whole Alternative 

could help continued adoption and preservation of conservation tillage methods, resulting in a 

small positive cumulative environmental impact. 

Glyphosate is already used on soybean and cotton in both conventional and GE varieties and 

the impacts of glyphosate use on water resources are well documented. Although glyphosate is 

very soluble in water, it is strongly adsorbed to soils; consequently, glyphosate is unlikely to 

leach into groundwater or surface water runoff following application (Giesy et al., 2000; USEPA, 1993). Relying on toxicological data, bioaccumulation and biodegradation studies, and 

acute and chronic tests on fish and other aquatic organisms, EPA has determined that “the 

potential for environmental effects of glyphosate in surface water is minimal” (US-EPA, 

2002b). 

Dicamba has been widely used in agriculture over the last four decades with dicamba’s peak use 

occurring in 1994. In the dicamba Reregistration Eligibility Decision (RED) document, EPA 

considered potential risks associated with dicamba use, and its degradate DCSA when 

appropriate, due to surface or ground water using screening level (high-end exposure) models 

to estimate environmental concentrations. The EPA then compared these exposure estimates 

to appropriate endpoints from mammalian, aquatic animal and plant ecotoxicity studies, and 

concluded dicamba meets the FIFRA standard for no unreasonable adverse effects on human 

health and the environment (see Appendices E and F to this Environmental Report). It is 

foreseeable that the frequency of dicamba detections in ground and surface water has the 

potential to increase as a result of the cultivation of DT soybean and DGT cotton; however,

levels of dicamba in water are not expected to increase above the levels already evaluated and 

considered by EPA. Considering the available monitoring data for ground and surface water 

during the period of dicamba’s most intensive use and when application rates were significantly 

higher than the rates proposed for us on DT soybean and DGT cotton, it is reasonable to 

assume that levels in ground and surface water that may result from the use of dicamba on DT

soybean or DGT cotton would be below the levels (high-end exposure modeling and 

monitoring data) considered by the EPA in the dicamba RED, and where EPA concluded 

would have no unreasonable adverse effects on human health or the environment. The total 

amount of the mix of herbicides that may be applied to DT soybean, DGT cotton, or 

subsequent varieties derived therefrom would be used in accordance with per application and

per year rates approved by EPA. EPA’s reregistration and registration review process ensures 

that each registered pesticide continues to meet the FIFRA registration standard, i.e., that 

pesticides will not cause unreasonable adverse effects when used as directed on product labels.

The potential future cultivation of stacked soybean and/or cotton varieties and the associated 

use of glyphosate in addition to dicamba and glufosinate are not expected to result in 

cumulative effects to water resources. Therefore, there are no past, present, or reasonably 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 288 of 946

foreseeable actions that would aggregate with effects of the proposed action that would have a 

negative impact on water resources.

V.P. CUMULATIVE IMPACTS: AIR QUALITY

A determination of nonregulated status of DT soybean and DGT cotton is not expected to 

result in changes in the current soybean and cotton cropping practices, with the exception of 

potential changes in the use of certain herbicides, and a potential decrease in tillage practices. 

As discussed above, potential impacts from changes to herbicide usage are outside the scope of 

APHIS’s action and fall instead within the jurisdiction of EPA’s oversight of pesticide usage. 

See Section I.B. As a result, no changes in air quality are anticipated.

Monsanto has indicated its intention to stack DT soybean and/or DGT cotton with other 

nonregulated soy and cotton varieties, particularly varieties conferring tolerance to the herbicide 

glyphosate. If combined with a glyphosate tolerance trait, DT soybean and/or DGT cotton 

would enable growers to use a combination of herbicides with different modes of action on 

soybean and/or cotton, an approach proposed to mitigate the future development of herbicideresistant weeds (Duke and Powles, 2009). Based on individual grower needs, this approach may 

reduce the need to use conventional tillage to control glyphosate-resistant weeds that exist in 

certain areas of the U.S. (Owen, 2011), which could potentially impact conservation tillage. A 

decrease in tillage practices may have air quality benefits. As discussed above, use of herbicides 

on DT soybean and/or DGT cotton alone or if stacked with other herbicide-tolerant or other 

traits is not expected to increase the overall number of acres to which herbicide would be 

applied. It would be a violation of federal law to apply these pesticides at application rates or 

timing that are not approved by EPA.

Monsanto has sought approval of the DGA salt of dicamba only for use on DT soybean

and/or DGT cotton. As discussed above, the formulation of the diglycolamine (DGA) salt of 

dicamba volatilized significantly less than a similar formulation of the DMA salt form (Egan 

and Mortensen 2012). Coupled with other label restrictions, and/or any other measures 

imposed by EPA, this will minimize the impact on air quality from spray drift. The use of lowvolatility formulations, including the DGA salt of dicamba used on DT soybean or DGT 

cotton is not expected to result in predicted mean exposures “close to zero only short distances 

away from the treated area.”(Egan and Mortensen 2012).

Monsanto has also indicated that its proposed dicamba product label would impose enforceable 

spray drift application requiremets that exceed requirements EPA deemed appropriate in the 

dicamba RED. EPA defines drift as “the movement of pesticide through air at the time of 

application or soon thereafter, to any site other than that intended for application” (US-EPA, 

2000b). Factors affecting drift include application equipment and method, weather conditions, 

topography, and the type of crop being sprayed (US-EPA, 2000b). The proposed FIFRA label 

instructions would obligate the applicator to follow relevant spray-drift prevention measures 

such as: proper nozzle type to ensure larger droplet size, ground application, proper boom 

height, and awareness of wind direction and speed. These restrictions and/or any measures 

imposed by EPA would effectively prevent harm from spray drift.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 289 of 946

V.Q. CUMULATIVE IMPACTS: CLIMATE CHANGE

A determination of nonregulated status for DT soybean and DGT cotton is not expected to 

result in changes in the current soybean and cotton cropping practices, with the exception of 

potential changes in the use of certain herbicides for weed management, and a potential 

decrease in conventional tillage practices. As discussed above, potential impacts from changes 

to herbicide usage are outside the scope of APHIS’s action and fall instead within the 

jurisdiction of EPA’s oversight of pesticide usage. See Section I.B. 

Some agricultural practices, such as tillage, can contribute to climate change through releasing 

GHG emissions from soil and emissions from associated fuel-burning equipment (Brookes and 

Barfoot, 2006; CAST, 2009). Monsanto has indicated its intention to develop a stacked hybrid 

with DT soybean and/or DGT cotton and commercially available soybean and cotton varieties 

conferring glyphosate tolerance. If combined with a glyphosate tolerance trait, DT soybean

and/or DGT cotton would enable growers to use a combination of herbicides with different 

modes-of-action on soybean and cotton, an approach proposed to mitigate the future 

development of herbicide-resistant weeds (Duke and Powles, 2009). Based on individual grower 

needs, this approach may reduce the need to use conventional tillage to control glyphosateresistant weeds (Owen, 2011). The continued use of conservation tillage associated with GE 

crops may reduce GHG emissions as a result of increased carbon sequestration in soils, 

decreased fuel consumption, and the reduction of nitrogen soil amendments (Towery and 

Werblow, 2010). 

As discussed above, use of herbicides on DT soybean and/or DGT cotton alone or if stacked 

with other herbicide-tolerant or other traits is not expected to increase the overall number of 

acres to which herbicide would be applied. It would be a violation of federal law to apply these 

pesticides at application rates or timing that are not approved by EPA.

There are no past, present, or reasonably foreseeable actions that would aggregate with effects 

of the proposed action that would have a negative impact on climate change.

V.R. CUMULATIVE IMPACTS: ANIMAL COMMUNITIES

A determination of nonregulated status of DT soybean and/or DGT cotton is not expected to 

result in changes in the current soybean and cotton cropping practices, with the exception of 

potential changes in the use of certain herbicides for weed management, and a potential 

decrease in conventional tillage practices. As discussed above, potential impacts from changes 

to herbicide usage are outside the scope of APHIS’s action and fall instead within the 

jurisdiction of EPA’s oversight of pesticide usage. See Section I.B. 

Monsanto has indicated its intention to stack DT soybean and/or DGT cotton with other 

nonregulated soy and cotton varieties, particularly varieties conferring tolerance to the herbicide 

glyphosate. If combined with a glyphosate tolerance trait, DT soybean and/or DGT cotton 

would enable growers to use a combination of herbicides with different modes of action on 

soybean and/or cotton, an approach proposed to mitigate the future development of herbicideresistant weeds (Duke and Powles, 2009). Based on individual grower needs, this approach may 

reduce the need to use conventional tillage to control glyphosate-resistant weeds (Owen, 2011). 

Reduced tillage improves habitat value through increased water quality, availability of waste 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 290 of 946

grain, retention of cover in fields, and increased populations of invertebrates (Brady, 2007; 

Sharpe, 2010). 

Both DT soybean and DGT cotton have been shown to have no toxic effects to animals. The 

FDA has completed its consultations on the safety of DT soybean and/or DGT cotton as 

animal feed. Monsanto intends to stack DT soybean and DGT cotton with soybean and cotton 

lines containing the 5-enolpyruvylshikimate-3-phosphate synthase (cp4 epsps) gene encoding 

the CP4 EPSPS protein conferring glyphosate tolerance. FDA has previously evaluated the 

safety of the CP4 EPSPS protein for feed and found no toxic effects to animals (US-FDA, 

1995). 

Glyphosate is already used in soybean and cotton in both conventional and glyphosate-tolerant

varieties. The herbicide has been previously reviewed by EPA for impacts on non-target 

organisms and is currently being evaluated as part of the registration review process, scheduled 

to be completed in 2015 (US-EPA, 1993, 2009a, 2009d). Likewise, dicamba is widely used in 

agriculture and has been reviewed by EPA for impacts on non-target organisms (U.S. EPA 

2009b), and it would be a violation of federal law for any herbicide to be used by growers 

inconsistent with the EPA label application rate. The total amount of the herbicides that may 

be applied to DT soybean and DGT cotton or subsequent varieties derived therefrom would be 

determined in accordance with per application and per year rates approved by EPA. EPA’s 

reregistration and registration review process ensures that each registered pesticide continues to 

meet the FIFRA registration standard, i.e., that pesticides will not cause unreasonable adverse 

effects when used as directed on product labels. 

Monsanto is developing a stewardship program that would include technological advancements 

in application and off-target movement of dicamba for application to DT soybean and/or 

DGT cotton, with a strong emphasis on grower and applicator training. Monsanto is also 

seeking U.S. EPA registration of a low volatility dicamba formulation (DGA salt) for ground 

application only. Monsanto’s proposed product label – which is currently pending before EPA 

– includes specific application requirements, including a no-spray buffer to protect adjacent 

dicamba-sensitive areas. To further minimize potential impacts from post application 

volatilitzation, Monsanto would not allow growers to use dimethylamine salt (DMA) of 

dicamba and/or dicamba acid on DT soybean. These measures, and/or others identified by 

EPA, will effectively address any potential impact of off-site movement of these herbicides. 

As discussed above, use of herbicides on DT soybean and DGT cotton alone or if stacked with 

other herbicide-tolerant or other traits is not expected to increase the overall number of acres 

to which herbicide would be applied. It would be a violation of federal law to apply these 

pesticides at application rates or timing that are not approved by EPA.

There are no past, present, or reasonably foreseeable actions that would aggregate with effects 

of the proposed action that would have an adverse impact on animal communities.

V.S. CUMULATIVE IMPACTS: PLANTS COMMUNITIES

A determination of nonregulated status of DT soybean and/or DGT cotton is not expected to 

result in changes in the current soybean or cotton cropping practices, with the exception of 

potential changes in the use of certain herbicides for weed management, and a potential 

decrease in conventional tillage practices. As discussed above, potential impacts from changes 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 291 of 946

to herbicide usage are outside the scope of APHIS’s action and fall instead within the 

jurisdiction of EPA’s oversight of pesticide usage. See Section I.B. 

Monsanto has indicated its intention to stack DT soybean and DGT cotton with other 

nonregulated soy and cotton varieties, particularly varieties conferring tolerance to the herbicide 

glyphosate. If combined with a glyphosate tolerance trait, DT soybean and DGT cotton would 

enable growers to use a combination of herbicides with different modes of action on soybean 

and/or cotton, an approach proposed to mitigate the future development of herbicide-resistant 

weeds (Duke and Powles, 2009). Based on individual grower needs, this approach may reduce 

the need to use conventional tillage to control glyphosate-resistant weeds (Owen, 2011), which 

could potentially impact conservation tillage. Reduced tillage improves soil quality and reduces 

soil erosion, sustaining both crop and non-crop plants.

Glyphosate is already used in soybean and cotton in both conventional and glyphosate-tolerant 

varieties. The herbicide has been previously reviewed by EPA for impacts on non-target 

organisms and is currently being evaluated as part of the registration review process, scheduled 

to be completed in 2015 (US-EPA, 1993, 2009a, 2009d). Likewise, dicamba is widely used in 

agriculture and has been reviewed by EPA for impacts on non-target organisms (EPA 2009b), 

and it would be a violation of federal law for any herbicide to be used by growers inconsistent 

with the EPA label application rate. Therefore, the total amount of the herbicides that may be 

applied to DT soybean and DGT cotton or subsequent varieties derived therefrom would be 

determined in accordance with per application and per year rates approved by EPA. EPA’s 

reregistration and registration review process ensures that each registered pesticide continues to 

meet the FIFRA registration standard, i.e., that pesticides will not cause unreasonable adverse 

effects when used as directed on product labels.

DT soybean and DGT cotton would provide alternatives to glyphosate in weed management 

systems, as dicamba and/or glufosinate will control the already glyphosate-resistant and hard to 

control broadleaf weeds. Diversified weed management programs that use herbicides from 

different groups, as well as varying cropping systems, rotating crops, and using mechanical as 

well as chemical weed control methods will potentially mitigate the potential for selection of 

herbicide-resistant weed populations (Green and Owen, 2011; Gunsolus, 2002; Powles, 2008; 

Sellers et al., 2011). 

To support the introduction of varieties containing DT soybean and DGT cotton, Monsanto 

will use multiple methods to distribute technical and stewardship information to growers, 

academics and grower advisors regarding the use of the product as part of a diversified weed 

management system. Growers who purchase Monsanto varieties containing DT soybean sign a 

limited use license known as the Monsanto Technology Stewardship Agreement (MTSA). The 

MTSA obligates growers to comply with certain requirements, including the Monsanto 

Technology Use Guide (TUG). The TUG will set forth the requirements and best practices for 

the cultivation of DT soybean including recommendations on weed resistance management 

practices. 

The weed resistance management practices that are designed to minimize the potential for the 

development of herbicide-resistant weeds will be articulated in the TUG and also be broadly 

communicated to growers and retailers. These practices will be communicated through a 

variety of means, including direct communications to each grower authorized to purchase a 

soybean variety containing DT soybean or a cotton variety containing DGT cotton, a public 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 292 of 946

website66, and reports in farm media publications. The overall weed resistance management 

program will be reinforced through collaborations with U.S. academics, who will provide their 

recommendations for appropriate stewardship of dicamba and glufosinate in soybean and 

cotton production, as well as by collaboration with crop commodity groups who have launched 

web-based weed resistance educational modules (WSSA 2012).

As discussed above, use of herbicides on DT soybean and DGT cotton alone, or if stacked

with other herbicide-tolerant or other traits, is not expected to increase the overall number of 

acres to which herbicide would be applied. It would be a violation of federal law to apply these 

pesticides at application rates or timing that are not approved by EPA.

There are no past, present, or reasonably foreseeable actions that would aggregate with effects 

of the proposed action that would have an adverse impact on plant communities.

V.T. CUMULATIVE IMPACTS: GENE FLOW AND WEEDINESS

The reproductive characteristics of the DT soybean and DGT cotton are substantially 

equivalent to other GE and non-GE soybean varieties of the same crops. See Appendix G to 

this Environmental Report.

V.T.1. Soybean

Given the reproductive characteristics of soybean, the probability for cross-pollination is low 

(Caviness, 1966; Ray et al., 2003). While cross-pollination can occur between adjacent plants 

and adjacent rows, it is unlikely that DT soybean or potential future varieties of DT soybean

stacked with other traits would be grown in the same fields as other soybean varieties. Methods 

commonly used to ensure seed purity such as isolation distances and rotation cycles that specify 

a minimum number of years between crops (Conner et al., 2003) would further minimize 

vertical gene transfer. Gene movement between sexually compatible soybean varieties would be 

no greater for a stacked DT soybean than it is for other non-GE or GE cultivars. The potential 

for horizontal gene flow to other unrelated organisms would be highly unlikely (USDA-APHIS, 

2012).

As discussed elsewhere in this report, DT soybean does not have any substantial weediness 

characteristics. Similarly, a soybean variety including dicamba-tolerance with glyphosate 

tolerance traits would not be expected to exhibit any weediness characteristics that would pose 

a plant pest risk.

Soybeans seldom exhibit dormancy and require specific environmental conditions to grow the 

following year (OECD, 2000), although volunteer soybean has been known to occur in some of 

the warmer regions of the U.S. In addition, volunteer soybean do not compete well with other 

crops and are easily controlled with common agronomic practices. DT soybean stacked with 

other herbicide-tolerant traits may lead to the need to manage volunteer soybeans in certain 

regions, especially in crops with herbicide tolerance to the same mode(s) of action.. 

 

66 http://www.monsanto.com/weedmanagement/Pages/default.aspx
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 293 of 946

Management of these volunteer soybeans may require the use of more narrow spectrum 

herbicides (such as atrazine in maize), or conventional mechanical control methods. While 

additional management practices for the control of volunteer stacked soybean varieties in 

rotation with other crops may be needed, these requirements are not expected to be anything 

beyond common agronomic practices.

V.T.2. Cotton

Although natural outcrossing can occur, cotton is normally considered to be a self-pollinating 

crop (Niles and Feaster 1984; OECD 2008). Research on cotton cross-pollination reveals that 

the frequency of cross-pollination falls off rapidly with distance from the pollen source (see 

Subsection II.D.2.c for additional details). Methods commonly used to ensure seed purity such 

as isolation distances and rotation cycles that specify a minimum number of years between 

crops (Conner et al., 2003) would further minimize vertical gene transfer. Gene movement 

between sexually compatible cotton varieties would be no greater for stacked DGT cotton than 

it is for other non-GE or GE cultivars. The potential for horizontal gene flow to other 

unrelated organisms would be highly unlikely (USDA-APHIS, 2012). 

With the exception of its tolerances to both dicamba and glufosinate, DGT cotton has been 

shown to be no different from non-GE cotton in its phenotypic, agronomic, and ecological 

characteristics including pollen diameter, viability and morphology (see Section VII.C.3 of 

petition 12-185-01p_a1 for details). Thus, DGT cotton is expected to be no different from 

other cotton in its ability to cross pollinate with other cotton. In addition, DGT cotton is not 

different from non-GE cotton in terms of seed dormancy and germination, susceptibility to or 

tolerance of disease or insect pests, and response to abiotic stressors (such as compaction, 

drought, high winds, nutrient deficiency, etc.), and would therefore be no different than nonGE cotton in its potential for volunteers and feral populations. In particular, the lack of hard 

seed, a well-accepted characteristic often associated with plants that are weeds, supports a 

conclusion of no increased weediness of DGT cotton compared to commercially cultivated 

cotton (see Appendix G to this Environmental Report. Similarly, a cotton variety including 

DGT cotton herbicide-tolerance traits with glyphosate tolerance would not be expected to 

exhibit any weediness characteristics that would pose a plant pest risk. 

DGT cotton stacked with other herbicide-tolerant traits may lead to the need to manage 

volunteer cotton in certain regions, especially in crops with herbicide tolerance to the same 

mode(s) of action. Management of this cotton may require the use of more narrow spectrum 

herbicides (such as atrazine in maize), or conventional mechanical control methods. While 

additional management practices for the control of volunteer stacked cotton varieties in 

rotation with other crops may be needed, these requirements are not expected to be anything 

beyond common agronomic practices.

V.T.3. Conclusion

No substantial cumulative effects on gene movement and weediness that would occur from a 

determination of nonregulated status to DT soybean or DGT cotton have been identified.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 294 of 946

V.U. CUMULATIVE IMPACTS: MICROORGANISMS

The main factors affecting microbial population size and diversity include soil type (texture, 

structure, organic matter, aggregate stability, pH, and nutrient content), plant type (providers of 

specific carbon and energy sources into the soil), and agricultural management practices (crop 

rotation, tillage, herbicide and fertilizer application, and irrigation) (Garbeva et al., 2004). A 

determination of nonregulated status for DT soybean and/or DGT cotton is not expected to 

result in changes in the current soybean and/or cotton cropping practices, with the exception 

of potential changes in the use of certain herbicides for weed management and a potential 

decrease in conventional tillage practices. If DT soybean and/or DGT cotton became 

commercially available and were stacked with other transgenic herbicide-tolerance traits, 

depending on the extent of its adoption, it may contribute to sustaining conservation tillage. 

Stacking DT soybean and/or DGT cotton with glyphosate would enable use of a combination 

of rates of different herbicide modes of action to be applied to soybean or cotton, an approach 

proposed to mitigate the future development of herbicide-resistant weeds (Duke and Powles, 

2009). Based on individual grower needs, this approach may reduce the need to use 

conventional tillage to control glyphosate-resistant weeds (Owen, 2011), which could 

potentially lead to a reduction in crop residue and SOM (Towery and Werblow, 2010). 

Maintaining adequate residue in the first three inches of the surface provides for a cooler and 

moister environment, increasing substrates and food for microorganisms (USDA-NRCS, 1996). 

Nor do the characteristics of the MON 87708 DMO, MON 88701 DMO or PAT (bar) pose 

any concern to soil microorganisms. The use of dicamba for agricultural purposes was first 

established in 1967, and EPA recently reaffirmed that the use of dicamba for agricultural 

purposes does not result in unreasonable adverse effects when applied according to label 

direction , including soybean and cotton production, with the reregistration in 2006 (U.S. EPA 

2009a). Impacts on soil microorganisms have not been raised as an important concern, and 

results of standardized tests with dicamba and dicamba formulations did not indicate any long 

term effects on soil microorganisms (Durkin and Bosch 2004). Results of standardized tests 

with dicamba and dicamba formulations indicate no long-term effects on functional processes 

of soil microorganisms (carbon respiration and nitrogen transformation) at rates proposed for 

dicamba on DT soybean and DGT cotton (EFSA 2007b). Glufosinate is currently used on 

cotton at the rates that would be the same as those used on DGT cotton. 

Glyphosate is already used in soybean and cotton in both conventional and glyphosate-tolerant

varieties. The herbicide has been previously reviewed by EPA for impacts on the environment 

and is currently being evaluated as part of the registration review process, scheduled to be 

completed in 2015 (US-EPA, 1993, 2009a, 2009d). Investigations of the impact of glyphosate 

on microorganisms are mixed (Weaver et al., 2007). Haney et al. (2002) and Araujo et al. (2003) 

report that glyphosate is mineralized by microorganisms that leads to an increase in their 

population and activity, while Busse et al. (2001) and Weaver et al. (2007) found little evidence 

of changes to soil microorganism’s population and activity and any declines recorded were 

small and not consistent throughout the season. It also has been reported that the use of 

glyphosate increases the colonization of soil borne fungal pathogens such as Fusarium spp. 

(Fernandez et al., 2009; Huber, 2010; Kremer and Means, 2009); however, peer reviewed 

research that report a direct correlation of glyphosate use to an increase in plant disease is 

limited and any connection to impacts on yield has not been established (Camberato et al., 

2011). The total amount of the mix of herbicides that may be applied to DT soybean, DGT 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 295 of 946

cotton or subsequent varieties derived therefrom would be determined in accordance with per 

application and per year rates approved by EPA. EPA’s process ensures that each registered 

pesticide continues to meet the FIFRA registration standard for human health and the 

environmental safety. EPA’s reregistration and registration review process ensures that each 

registered pesticide continues to meet the FIFRA registration standard, i.e., that pesticides will 

not cause unreasonable adverse effects when used as directed on product labels.

As discussed above, use of herbicides on DT soybean and/or DGT cotton alone or if stacked 

with other herbicide-tolerant or other traits is not expected to increase the overall number of 

acres to which herbicide would be applied. It would be a violation of federal law to apply these 

pesticides at application rates or timing that are not approved by EPA.

Based on the above information, there are no past, present, or reasonably foreseeable actions 

that would aggregate with effects of the proposed action that would have a negative impact on 

microorganisms; rather, there may be slight beneficial cumulative impacts from sustaining 

conservation tillage rates in soybean and cotton production. 

V.V. CUMULATIVE IMPACTS: BIODIVERSITY

A determination of nonregulated status of DT soybean and DGT cotton is not expected to 

result in changes in the current soybean or cotton cropping practices, with the exception of 

potential changes in the use of certain herbicides for weed management, and a potential 

decrease in conventional tillage practices. As discussed above, potential impacts from changes 

to herbicide usage are outside the scope of APHIS’s action and fall instead within the 

jurisdiction of EPA’s oversight of pesticide usage. See Section I.B. 

Monsanto has indicated its intention to stack DT soybean and DGT cotton with other 

nonregulated soy and cotton varieties, particularly varieties conferring tolerance to the herbicide 

glyphosate. If combined with a glyphosate tolerance trait, DT soybean and DGT cotton would 

enable growers to use a combination of herbicides with different modes of action on soybean 

and/or cotton, an approach proposed to mitigate the future development of herbicide-resistant 

weeds (Duke and Powles, 2009). Based on individual grower needs, this approach may reduce 

the need to use conventional tillage to control glyphosate-resistant weeds (Owen, 2011). 

Reduced tillage improves habitat value through increased water quality, availability of waste 

grain, retention of cover in fields, and increased populations of invertebrates (Brady, 2007; 

Sharpe, 2010). Incorporation of herbicide tolerance in the crop may facilitate the grower 

adoption of conservation and no-till strategies, thereby improving soil characteristics enhancing 

soil fauna and flora (Towery and Werblow, 2010), increasing the flexibility of crop rotation, and 

facilitating strip cropping (Fernandez-Cornejo et al., 2002), all contributing to the health of the 

faunal and floral communities in and around soybean fields that promotes biodiversity (Palmer 

et al., No Date; Sharpe, 2010).

Glyphosate is already used in soybean and cotton in both conventional and glyphosate-tolerant 

varieties. The herbicide has been previously reviewed by EPA for impacts on the environment 

and is currently being evaluated as part of the registration review process, scheduled to be 

completed in 2015 (US-EPA, 1993, 2009a, 2009d). Likewise, dicamba is widely used in 

agriculture and has been reviewed by EPA for impacts on non-target organisms (U.S. EPA 

2009b). The total amount of the mix of herbicides that may be applied to DT soybean

soybean, DGT cotton, or subsequent varieties derived therefrom would be used in accordance 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 296 of 946

with per application and per year rates approved by EPA. EPA’s reregistration and registration 

review process ensures that each registered pesticide continues to meet the FIFRA registration 

standard, i.e., that pesticides will not cause unreasonable adverse effects when used as directed 

on product labels.

Monsanto is developing a stewardship program that would include technological advancements 

in application and off-target movement of dicamba for application to DT soybean and/or 

DGT cotton, with a strong emphasis on grower and applicator training. Monsanto is also 

seeking U.S. EPA registration of a low volatility dicamba formulation (DGA salt) for ground 

application only. Monsanto’s proposed product label – which is currently pending before EPA 

– includes specific application requirements, including a no-spray buffer to protect adjacent 

dicamba-sensitive areas. To further minimize potential impacts from post application 

volatilitzation, Monsanto would not allow growers to use dimethylamine salt (DMA) of 

dicamba and/or dicamba acid on DT soybean. These measures, and/or others identified by 

EPA, will effectively address any potential impact of off-site movement of these herbicides. 

As discussed above, use of herbicides on DT soybean soybean and/or DGT cotton alone or if 

stacked with other herbicide-tolerant or other traits is not expected to increase the overall 

number of acres to which herbicide would be applied. It would be a violation of federal law to 

apply these pesticides at application rates or timing that are not approved by EPA.

Based on the above information, there are no past, present, or reasonably foreseeable actions 

that would aggregate with effects of the proposed action that would have an adverse impact on 

biodiversity.

V.W. CUMULATIVE IMPACTS: HUMAN HEALTH

A determination of nonregulated status of DT soybean and/or DGT cotton would have no 

adverse impact on human health. The FDA has completed its consultations on the safety of 

DT soybean and DGT cotton as food and animal feed. Monsanto intends to stack DT soybean

and DGT cotton with soybean and cotton lines containing the 5-enolpyruvylshikimate-3-

phosphate synthase (cp4 epsps) gene encoding the CP4 EPSPS protein conferring glyphosate 

tolerance. FDA has previously evaluated the safety of the CP4 EPSPS protein for feed and 

found no toxic effects to animals (US-FDA, 1995). As specified in 40 CFR §174.523, EPA has 

reviewed the safety of the CP4 EPSPS protein and has established a tolerance exemption for 

the protein and the genetic material necessary for its production in or on all raw agricultural 

commodities (US-EPA, 2012b). This exemption is based on a safety assessment that included 

rapid digestion in simulated gastric fluids, lack of homology to known toxins and allergens, and 

lack of toxicity in an acute oral mouse gavage study. The lack of any documented reports of 

adverse effects since the introduction of other glyphosate crops in 1993 suggests the safety of 

its use.

Worker safety is taken into consideration by EPA in the pesticide registration process and 

reregistration process. Pesticides are regularly reevaluated by EPA for each pesticide to 

maintain its registered status under FIFRA. EPA’s process ensures that each registered pesticide 

continues to meet the FIFRA registration standard for human health. 

Glyphosate has been widely used on soybean since the first glyphosate-tolerant soybean variety 

in 1994 was determined to be no longer subject to the regulatory requirements of 7 CFR part 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 297 of 946

340 or the plant pest provisions of the Plant Protection Act (Heiniger 2000). The use of 

glyphosate herbicide in accordance with federal law does not result in adverse effects on 

development, reproduction, or endocrine systems in mammals. Under present and expected use 

conditions, and when used in accordance with the EPA label, glyphosate does not pose a 

human health risk. Pesticide residue tolerances for glyphosate are listed in 40 CFR § 180.364 

and include acceptable concentrations for soybean seeds (US-EPA, 2011b). 

Dicamba has been registered in the U.S. for use on food crops since 1967 (U.S. EPA 2009d)

and has been widely used in agricultural production for over forty years. The EPA concluded 

there is reasonable certainty that no harm will result to the general population, or to infants and 

children, as a result of aggregate (all) exposure to dicamba residues. Established food and feed 

tolerances for dicamba are listed at 40 CFR 180.227, and in addition to the crop plants, they 

include residue limits for meat, milk, and meat by-products that may arise when livestock 

consume dicamba-treated commodities. The total amount of the mix of herbicides that may be 

applied to DT soybean, DGT cotton, or subsequent varieties derived therefrom would be used 

in accordance with per application and per year rates approved by EPA. When used in 

compliance with the EPA label, pesticides do not cause unreasonable adverse effects to human 

health and worker safety. 

In light of the above information, there are no past, present, or reasonably foreseeable actions 

that would aggregate with effects of the proposed action that would have an adverse impact on 

human health.

V.X. CUMULATIVE IMPACTS: ANIMAL FEED

A determination of nonregulated status of DT soybean and/or DGT cotton would have no 

adverse impact on animal health. The FDA has completed its consultations on the safety of DT 

soybean and DGT cotton as animal feed. Monsanto intends to stack DT soybean and DGT 

cotton with soybean and cotton lines containing the 5-enolpyruvylshikimate-3-phosphate 

synthase (cp4 epsps) gene encoding the CP4 EPSPS protein conferring glyphosate tolerance. 

FDA has previously evaluated the safety of the CP4 EPSPS protein for feed and found no toxic 

effects to animals (US-FDA, 1995). As specified in 40 CFR §174.523, EPA has reviewed the 

safety of the CP4 EPSPS protein and has established a tolerance exemption for the protein and 

the genetic material necessary for its production in or on all raw agricultural commodities (USEPA, 2012b). This exemption is based on a safety assessment that included rapid digestion in 

simulated gastric fluids, lack of homology to known toxins and allergens, and lack of toxicity in 

an acute oral mouse gavage study. The lack of any documented reports of adverse effects since 

the introduction of other glyphosate crops in 1996 suggests the safety of its use.

Glyphosate has been widely used on soybean since the first glyphosate-tolerant soybean variety 

was determined to be no longer subject to the regulatory requirements of 7 CFR part 340 or the 

plant pest provisions of the Plant Protection Act in 1994. The use of glyphosate herbicide in 

accordance with federal law does not result in adverse effects on development, reproduction, or 

endocrine systems in mammals. Under present and expected use conditions, and when used in 

accordance with the EPA label, glyphosate does not pose a health risk to animals as an animal 

feed concern. Pesticide residue tolerances for glyphosate are listed in 40 CFR § 180.364 and 

include acceptable concentrations for soybean forage, hay, hulls, and seed (US-EPA, 2011b).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 298 of 946

Dicamba has been registered in the U.S. for use on food crops since 1967 (U.S. EPA 2009d)

and has been widely used in agricultural production for over forty years. A comprehensive 

safety evaluation and risk assessment conducted by EPA concluded that dicamba has low 

toxicity to mammals, is not a carcinogen, does not adversely affect reproduction and 

development, and does not bioaccumulate in mammals (U.S. EPA 2009d). An ecotoxicological 

risk assessment concluded that the use of dicamba does not pose an unreasonable risk of 

adverse effects to non-target species, such as birds and fish, when used according to label 

directions, nor does it pose an unreasonable risk of adverse effects to insects outside of the 

application area (U.S. EPA 2009d). Established food and feed tolerances for dicamba are 

listed at 40 CFR 180.227, and in addition to the crop plants, they include residue limits for 

meat, milk, and meat by-products that may arise when livestock consume dicamba-treated 

commodities.

The amount of different herbicides that may be applied to DT soybean, DGT cotton, or 

subsequent varieties derived therefrom would be used in accordance with per application and

per year rates approved by EPA. EPA’s reregistration and registration review process ensures 

that each registered pesticide continues to meet the FIFRA registration standard, i.e., that 

pesticides will not cause unreasonable adverse effects when used as directed on product labels. 

In light of the above information, there are no past, present, or reasonably foreseeable actions 

that would aggregate with effects of the proposed action that would have an adverse impact on 

animal health.

V.Y. CUMULATIVE IMPACTS: DOMESTIC ECONOMIC ENVIRONMENT

There are potential implications of the change in herbicide use as a result of a determination of 

non-regulated status of DT soybean and/or DGT cotton, particularly with regard to the 

management of glyphosate-resistant weeds. As discussed above, potential impacts from changes 

to herbicide usage are outside the scope of APHIS’s action and fall instead within the 

jurisdiction of EPA’s oversight of pesticide usage. See Section I.B.

Monsanto has indicated its intention to stack DT soybean and DGT cotton with commercially 

available soybean and cotton varieties conferring glyphosate tolerance. These stacked varietals 

have the potential to improve grower management strategies for control of glyphosate-resistant 

weeds and also improve grower economics.

DT soybean stacked with glyphosate tolerance would enable farmers to choose dicamba, 

glyphosate, and a mixture of the two for post-emergence weed control. DGT cotton stacked 

with glyphosate tolerance would allow for the same options, plus the additional ability to apply 

glufosinate. This herbicide management strategy is anticipated to sustain the long-term viability 

of the glyphosate-tolerant cropping system and preserve the benefits it provides to growers, the 

agricultural industry, and society. The adoption of such a diverse weed management strategy, 

incorporating several herbicides with alternative modes of action, may initially cost more than 

the conventional single-herbicide approach, but these costs are likely to be offset by an increase 

in yields in those fields where the weed pressure has been reduced (Weirich et al. 2011). 

As discussed previously, both glyphosate-tolerant soy and cotton were rapidly adopted 

following their introduction in the U.S. and now account for the majority of soy and cotton 

acres planted. Herbicide-tolerant crops, primarily glyphosate-tolerant, have affected agricultural 
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production globally and similar adoption profiles have occurred in other geographies where 

glyphosate-tolerant crops have been introduced (e.g., Argentina, Brazil, Canada). Early efforts 

to characterize the reasons that glyphosate-tolerant crops achieved such rapid adoption focused 

on profitability, yield, and costs (Carpenter and Gianessi 2001). Information from recent 

grower surveys cite other non-pecuniary advantages such as simplicity, convenience, flexibility 

and safety as some of the primary reasons for using glyphosate-tolerant crops (Hurley et al. 

2009b). One of the biggest advantages of glyphosate-tolerant cropping systems has been the 

reduction in labor. The reduction in labor allowed growers more free time to pursue other 

activities and freed up farm management time for non-farm income. 

The adoption of DT soybean and DGT cotton is expected to help maintain the economic and 

non-pecuniary benefits growers have realized using the glyphosate-tolerant system. These 

include time and labor savings to growers through the simplicity and flexibility of a dicamba, 

and glyphosate (and glufosinate for DGT cotton) weed control system over alternative 

herbicides that are authorized for use in soy and cotton production. In addition, the ability to 

use dicamba in combination with glyphosate (and glufosinate in the case of cotton) will further 

preserve the benefits the glyphosate-tolerant system has provided in the form of increasing 

adoption of conservation tillage acres. The cultivation of DT soybean DGT cotton provides a 

method to manage the development of glyphosate-, glufosinate- or dicamba-resistant weeds, as 

well as weeds resistant to other herbicide class of chemistries, and this benefit is expected to 

outweigh additional costs of controlling resistant weeds through the dicamba, glufosinate, and 

glyphosate weed control system.

Based on these factors, no net negative cumulative effects on domestic economics have been 

identified associated with the cultivation of DT soybean and/or DGT cotton. If growers adopt 

stacked varieties and take advantage of the weed management strategy incorporating herbicides 

with different modes of action to control glyphosate-resistant weeds, local farm economics may

be positively impacted. In light of the above information, there are no past, present, or 

reasonably foreseeable actions that would aggregate with effects of the proposed action that 

would have an adverse impact on the domestic economic environment.

V.Z. CUMULATIVE IMPACTS: TRADE ECONOMIC ENVIRONMENT

A determination of nonregulated status of DT soybean and DGT cotton, including subsequent 

stacked herbicide tolerant varieties, are not expected to adversely impact the trade economic 

environment and may have a positive impact through increased yields in soybean or cotton 

areas of the U.S. affected by glyphosate-resistant weeds. Current and historic economic 

evidence indicates that herbicide-tolerant soybean and cotton technology has the potential to 

increase domestic production at lower cost. This trend of lower production costs could 

enhance international soybean trade by making U.S. products more competitive in the global 

market.

The subsequent development and global adoption of these stacked varieties could provide 

another herbicide-tolerant management choice for growers. As the value and benefits of these 

products are realized, particularly in areas of the U.S. where glyphosate-resistant weeds have 

emerged, DT soybean, DGT cotton, and subsequent stacked varieties may have potential for 

export as a seed product.
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In light of the above, there are no past, present, or reasonable foreseeable actions that in 

aggregate with effects of the proposed action would negatively impact the trade economic 

environment.

VI. THREATENED AND ENDANGERED SPECIES ANALYSIS

Congress passed the Endangered Species Act (ESA) of 1973, as amended, to prevent 

extinctions facing many species of fish, wildlife, and plants. The purposes of the Endangered 

Species Act (ESA) are to provide a means for conserving the ecosystems upon which 

endangered and threatened species depend and a program for the conservation of such 

species.67 To implement the ESA, the U.S. Fish and Wildlife Service (USFWS) works in 

cooperation with the National Marine Fisheries Service (NMFS); other Federal, State, and local 

agencies; Tribes; non-governmental organizations; and private citizens. Before a plant or 

animal species can receive the protection provided by the ESA, it must first be added to the 

Federal list of threatened and endangered wildlife and plants. 

A species is added to the list when the USFWS and/or NMFS determined it to be endangered 

or threatened because of any of the following factors: 

The present or threatened destruction, modification, or curtailment of its habitat or range; 

Overutilization for commercial, recreational, scientific, or educational purposes; 

Disease or predation; 

The inadequacy of existing regulatory mechanisms; and 

The natural or manmade factors affecting its survival. 

In accordance with the ESA, once an animal or plant is added to the list, protective measures 

apply to the species and its habitat. These measures include protection from adverse effects of 

Federal activities. 

Section 7 (a)(2) of the ESA requires that Federal agencies, in consultation with USFWS and/or 

the NMFS, ensure that any action they authorize, fund, or carry out is not likely to jeopardize 

the continued existence of a listed species or result in the destruction or adverse modification 

of designated critical habitat. It is the responsibility of the Federal agency taking the action to 

assess the effects of its action and to consult with the USFWS and NMFS if it is determined 

that the action “may affect” listed species or critical habitat. To facilitate APHIS’ ESA 

consultation process, APHIS met with the USFWS from 1999 to 2003 to discuss factors 

relevant to APHIS’ regulatory authority and effects analysis for petitions for nonregulated 

status, and developed a process for conducting an effects determination consistent with the 

Plant Protection Act of 2000 (Title IV of Public Law 106-224). This process is described in a 

decision tree document, which has been included in recent Environmental Assessments and the 

 

67 Endangered Species Act of 1973 (as amended through Public Law 107-136), Section 2(b)
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Final Environmental Impact Statement for glyphosate-tolerant H7-1 sugar beet (USDA-APHIS 

2011; 2012). APHIS has used this process to help fulfill its obligations and responsibilities 

under Section 7 of the ESA for GE regulatory actions.

VI.A. POTENTIAL FOR GE PLANT TO AFFECT THREATENED OR 

ENDANGERED SPECIES

APHIS’ regulatory authority over genetically engineered (GE) organisms under the PPA is 

limited to those GE organisms for which it has reason to believe might be a plant pest or those 

for which APHIS does not have sufficient information to determine that the GE organism is 

unlikely to pose a plant pest risk (7 CFR 340.1). EPA has sole authority to regulate the use of

any herbicide. After completing a plant pest risk analysis, if APHIS determines that the GE 

organism does not pose a plant pest risk, then the GE organism would no longer be subject to 

the plant pest provisions of the PPA or to the regulatory requirements of 7 CFR part 340 and, 

therefore, APHIS will grant a determination of nonregulated status.

In accordance with the ESA, APHIS will review its action under the PPA relative to the GE 

organism to determine if its action may affect listed species or critical habitat just as EPA 

reviews and regulates herbicides to determine impact on threatened and endangered species 

and/or critical habitats. Monsanto has prepared the information in this Environmental Report 

to assist APHIS in making this determination from DT soybean and DGT cotton. In its

review, for each GE plant, APHIS considers the following information, data, and questions 

(USDA-APHIS 2012):

A review of the biology and taxonomy of the crop plant and its sexually compatible relatives; 

Characterization of each transgene with respect to its structure and function and the nature of 

the organism from which it was obtained; 

A determination of where the new transgene and its products (if any) are produced in the plant 

and their quantity; 

A review of the agronomic performance of the plant, including disease and pest susceptibilities, 

weediness potential, and agronomic and environmental impacts; 

Determination of the concentrations of known plant toxicants (if any are known in the plant); 

Analysis to determine if the transgenic plant is sexually compatible with any threatened or 

endangered plant species or a host of any threatened or endangered plant or animal species; and 

Any other information that may inform the potential for an organism to pose a plant pest risk.

VI.B. POTENTIAL FOR DT SOYBEAN TO AFFECT THREATENED OR 

ENDANGERED SPECIES

To identify any potential effects of DT soybean on threatened and endangered plant species, 

the potential for DT soybean to cross with a listed species was evaluated. Soybean is not native 

to the U.S., and DT soybean is not sexually compatible with any federally listed TES or a native 

species proposed for listing. Like other G. max, DT soybean will likely be a poor competitor 
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with native vegetation and will not survive outside of cultivation (Baker 1965). Thus, DT 

soybean is not expected to interbreed with any plant species or displace natural vegetation in 

the U.S. 

To identify potential effects on threatened and endangered animal species, the risks to 

threatened and endangered animals from consuming DT soybean or vegetative materials are 

considered. In this analysis, the biology of DT soybean and the agricultural practices associated 

with the cultivation of DT soybean have been considered for potential adverse impact on TES 

and their critical habitats. Bioinformatics analysis determined that MON 87708 DMO does not 

share amino acid sequence similarities with known allergens, gliadins, glutenins, or protein 

toxins. (See Appendix G to this Environmental Report) MON 87708 DMO was rapidly 

digested in in vitro assays using simulated gastric and intestinal fluids and did not show any 

adverse effects when administered to mice via oral gavage at levels far in excess of that 

reasonably expected to be consumed by humans or animals. Compared to commercially 

cultivated soybean, DT soybean does not express any additional proteins or natural toxicants 

that are known to directly or indirectly affect a listed TES or species proposed for listing by the 

U.S. Fish and Wildlife Service. Compositional analysis of DT soybean for nutrients and antinutrients indicated that the harvested seed and forage from DT soybean were compositionally 

equivalent to commercially cultivated soybean. Thus, DT soybean would not be expected to 

have any impacts on TES that would differ from commercially cultivated soybean.

The only TES animal listed that occupies habitat that is likely to include soybean fields and that 

might feed on soybean is the Federally Endangered Delmarva Peninsula Fox Squirrel, Sciurus 

niger cinereus, found in areas of the mid-Atlantic Eastern seaboard.68 It is known to utilize certain 

agricultural lands readily, and its diet includes acorns, nuts/seeds of hickory, beech, walnut, and 

loblolly pine, buds and flowers of trees, fungi, insects, fruit, and an occasional bird egg. Given 

its varied diet, the safety of MON 87708 DMO, and the demonstrated compositional, 

agronomic and phenotypic equivalence of DT soybean to commercially cultivated soybean, it is 

concluded that no biologically significant changes to the habitat or diet of the Delmarva 

Peninsula Fox Squirrel are expected. Consequently, the planting of DT soybean is not expected 

to impact the Delmarva Peninsula Fox Squirrel. 

As part of the analysis for TES and critical habitat, Monsanto considered whether DT soybean

has any characteristics that may allow the plant to naturalize in the environment and potentially 

have an effect on TES. In doing so, Monsanto assessed whether DT soybean is any more likely 

to become a weed than commercially cultivated soybean. Weediness could potentially affect 

TES or critical habitat if DT soybean were to become naturalized in the environment. As 

discussed in Section II.D.1.c., cultivated soybean is largely self-pollinating, with minimal gene 

movement, and no wild (native) or feral species of Glycine are found in the U.S. With the 

exception of its tolerance to dicamba and, DT soybean has been shown to be no different from 

commercially cultivated soybean in its phenotypic, agronomic and ecological characteristics, 

including pollen diameter, viability, and morphology. In addition, DT soybean is not different 

from commercially cultivated soybean in terms of seed dormancy and germination, 

 

68 Source is from website: http://ecos.fws.gov/tess_public/SpeciesReport.do; [Accessed May 14, 2009].
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susceptibility to or tolerance of disease or insect pests, and response to abiotic stressors (such as 

compaction, drought, high winds, nutrient deficiency, etc.), and would, therefore be no 

different than commercially cultivated soybean in its potential for volunteers and feral 

populations. In particular, the lack of hard seed, a well-accepted characteristic often associated 

with plants that are weeds, supports a conclusion of no increased weediness of DT soybean

compared to commercially cultivated soybean. Collectively, this information indicates that DT 

soybean is no different from commercially cultivated soybean in its weediness potential.

In summary, no stressor associated with the introduction of DT soybean is expected to affect 

the reproduction, numbers, or distribution of a listed TES, candidate species, or species 

proposed for listing. As a result, a detailed site-specific (or spatially explicit) exposure analysis 

for individually listed TES is not necessary. Collectively, all the laboratory and field trial data on 

DT soybean support the conclusion that there would be no difference with cultivation of DT

soybean from effects that would occur from the production of commercially cultivated 

soybean. Soybean is not native to the U.S., and DT soybean is not sexually compatible with any 

federally listed TES or a species proposed for listing. Like other G. max, DT soybean will likely 

be a poor competitor with native vegetation and will not survive outside of cultivation (Baker 

1965). Thus, DT soybean is not expected to interbreed with any plant species or displace 

natural vegetation in the U.S.

VI.C. POTENTIAL FOR DGT COTTON TO AFFECT THREATENED OR 

ENDANGERED SPECIES

To identify any potential effects of DGT cotton on threatened and endangered plant species, 

the potential for DGT cotton to cross with a listed species was evaluated. Cotton is in the 

genus Gossypium and has the ability to cross with some other species of cotton in the same 

genus (OECD 2008). A review of the list of threatened and endangered plant species in the 

U.S. shows that DGT cotton would not be sexually compatible with any listed threatened or 

endangered plant species, species proposed for listing, or candidate species, as none of these 

listed, proposed, or candidate species are in the same genus or known to cross pollinate with 

species of the genus Gossypium (USFWS 2012; 2013). As discussed in Section II.D.2.c., there is 

only one native Gossypium species found in U.S. cotton-growing regions, in Arizona, and crosspollination of that species with commercial cotton would not produce fertile offspring (Fryxell 

1984; Waghmare et al. 2005). 

To identify potential effects on threatened and endangered animal species, the risks to 

threatened and endangered animals from consuming DGT cotton, cottonseed or vegetative 

materials are considered. As discussed in Appendix G to this Environmental Report, there is 

no difference in the composition and nutritional quality of DGT cottonseed compared with 

commercially cultivated cottonseed. The allergenicity and toxicity of the MON 88701 DMO 

and PAT(bar) proteins were also evaluated. The research summarized and referenced in 

Appendix G found no differences in allergenicity and toxicity compared to the analogous 

protein in commercially cultivated cotton. Both types of proteins are ubiquitous in nature and 

normally present in food and feeds derived from these plant and microbial sources. As 

discussed in Appendix G, during field trials with DGT cotton, no biologically relevant changes 

in arthropod feeding damage were observed, indicating similar arthropod susceptibility for 

DGT cotton compared to commercially cultivated cotton. As DGT cotton exhibits no toxic 

effects on insects or other animals it is concluded that they will not be affected. In addition, the 

cultivation of DGT cotton does not impact the nutritional quality, safety or availability of 
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animal feed. Based on these results, no effects to any TES animal species (or candidate species, 

or species proposed for listing) that may feed on DGT cotton plant parts would be expected.

As part of the analysis for TES and critical habitat, Monsanto considered whether DGT cotton

has any characteristics that may allow the plant to naturalize in the environment and potentially 

have an effect on TES. In doing so, Monsanto assessed whether DGT cotton is any more 

likely to become a weed than commercially cultivated cotton. Weediness could potentially 

affect TES or critical habitat if DGT cotton were to become naturalized in the environment. 

As discussed in Section II.D.2.c, cultivated cotton is largely self-pollinating, and no wild (native) 

or feral species of Gossypium have been found in cotton-growing areas. As discussed in 

Appendix G, with the exception of its tolerances to both dicamba and glufosinate, DGT cotton

has been shown to be no different from commercially cultivated cotton in its phenotypic, 

agronomic and ecological characteristics, including pollen diameter, viability, and morphology. 

In addition, DGT cotton is not different from commercially cultivated cotton in terms of seed 

dormancy and germination, susceptibility to or tolerance of disease or insect pests, and 

response to abiotic stressors (such as compaction, drought, high winds, nutrient deficiency, 

etc.), and would, therefore be no different than commercially cultivated cotton in its potential 

for volunteers and feral populations. In particular, the lack of hard seed, a well-accepted 

characteristic often associated with plants that are weeds, supports a conclusion of no increased 

weediness of DGT cotton compared to commercially cultivated cotton. Collectively, this

information indicates that DGT cotton is no different from commercially cultivated cotton in 

its weediness potential.

In summary, no stressor associated with the introduction of DGT cotton is expected to affect 

the reproduction, numbers, or distribution of a listed TES, candidate species, or species 

proposed for listing. As a result, a detailed site-specific (or spatially explicit) exposure analysis 

for individually listed TES is not necessary. Collectively, all the laboratory and field trial data on 

DGT cotton support the conclusion that there would be no difference with cultivation of DGT 

cotton from effects that would occur from the production of commercially cultivated cotton. 

Cotton is not sexually compatible with, nor does it serve as a host species for, any listed species, 

candidate species or species proposed for listing. Based on the characteristics of the introduced 

protein and comparative compositional assessments, consumption of DGT cotton by any listed 

species or species proposed for listing will not result in a toxic or allergic reaction. 

VI.D. POTENTIAL IMPACTS OF DICAMBA USE ON THREATENED AND 

ENDANGERED SPECIES 

As discussed above, APHIS met with USFWS officials on June 15, 2011 to discuss whether 

APHIS has any obligations under the ESA to analyze the impacts of herbicide use associated 

with all GE crops on TES. As a result of these joint discussions, the USFWS and APHIS have 

agreed that it is not necessary for APHIS to perform an ESA effects analysis on herbicide use 

associated with GE crops. As discussed elsewhere in this document, EPA has the sole 

authority to authorize or regulate the use of dicamba, or any other herbicide, by soybean and 

cotton growers. Under 7 CFR 340, APHIS only has the authority to regulate DT soybean and 

DGT cotton or any GE organism if the agency believes it may pose a plant pest risk. The 
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Ninth Circuit in Center for Food Safety v. Vilsack confirmed this point specifically regarding 

herbicide uses, concluding that the ESA’s consultation duty is triggered only when the agency 

has authority to take action and discretion to decide what action to take.69 In that case, APHIS 

had reached an ESA “no effect” conclusion as to the plant specifically, which was not 

challenged. The plaintiffs contended, however, that APHIS was required to perform an ESA 

consultation as to the herbicide. But APHIS lacked authority over the herbicide uses. Once 

APHIS concluded that RRA was not a plant pest, the agency had no jurisdiction to continue 

regulating the crop as a plant pest.70 The agency’s deregulation of RRA was thus a 

nondiscretionary act that did not trigger the agency’s duty to consult under the ESA regarding 

herbicide uses.71 In this instance, APHIS has no obligation under NEPA or the ESA to 

consider the effects on TES of herbicide use associated with DT soybean or DGT cotton 

crops. Nor does APHIS have an obligation to consult with the USFWS under the ESA given 

that the GE crops do not constitute plant pest risks. EPA is responsible for evaluating the 

effects on TES of herbicides on cotton and soybean, and EPA will only approve the use of 

dicamba on DT soybean and DGT cotton if it determines that the uses will not affect 

threatened and endangered species. Details of EPA’s Endangered Species Protection Program 

(ESPP) and TES evaluation program, as well as the ecological risks of dicamba are discussed in 

Appendices A and F to this Environmental Report. 

It is important to note that the use of herbicides in the production of soybean and cotton 

would not be unique to the production of DT soybean and DGT cotton, and DT soybean and 

DGT cotton are not dependent on the use of dicamba for their production lifecycles. As noted 

in Section II.B.2.d, herbicides are used on over 99% of cotton acres. Various herbicides other 

than dicamba are typically used to control weeds during production of commercially cultivated 

cotton, and these herbicides could presumably be used in production of DGT cotton. An 

analysis of herbicide use in cotton and the associated risks are described in more detail in 

Appendices A and F to this Environmental Report. 

Conservation tillage and no-till practices have a positive impact on wildlife (Towery and 

Werblow 2010). Benefits include decreased soil erosion and improved water quality in 

receiving waters, retention of cover, availability of waste grain on the soil surface for feed, and 

increased populations of invertebrates as a food source (Sharpe 2010). As described in Sections 

II.B.1.c and II.B.2.c, the use of herbicides, particularly with herbicide-tolerant crops, facilitates 

the use of conservation tillage practices. 

Monsanto has requested approval of the use of a low-volatility DGA dicamba formulation on 

DT soybean and DGT cotton by amending the label for EPA Registration Number 524-582. 

In the EPA’s review of this registration request, they will apply the same statutory-based 

regulatory requirements as they do to all pesticides. Because the proposed use of dicamba on 

DT soybean and DGT cotton falls within the use rate limits established by EPA in the 2006 

 

69 Ctr. for Food Safety v. Vilsack, 718 F.3d at 842.

70 Id. 

71 Id.
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RED, it can be concluded that risks to non-target organisms from the use of dicamba on DT

soybean and DGT cotton have been assessed. Pending EPA approval, additional application 

requirements will be included in the FIFRA label to further limit dicamba offsite movement. In 

addition, Monsanto is implementing a robust stewardship program that will include a strong

emphasis on grower and applicator training. Furthermore, prior to commercialization of DT 

soybeans and DGT cotton, Monsanto will implement an endangered species mitigation system 

for dicamba. The implemented system will either be an EPA-specific system and/or a webbased system, similar to that currently available for glyphosate at PreServe.org. This will 

facilitate applicator and grower implementation of use restrictions for protection of threatened 

and endangered non-monocotyledonous terrestrial plant species. Glufosinate is currently 

undergoing Registration Review at EPA, which will take into consideration glufosinate’s 

potential impact on endangered species (U.S. EPA 2008b). 

In addition to the web-based endangered species mitigation system for dicamba, Monsanto will 

take steps to manage dicamba offsite movement through inclusion of specific application 

requirements on the proposed FIFRA as EPA directs. The authority to restrict the use of 

pesticides or impose measures to mitigate their risk belongs solely to EPA; no other agency has 

the regulatory authority. For example, Monsanto’s proposed label restrictions for in-crop use 

on DT soybean and DGT cotton—which are currently pending before EPA—include, but are 

not limited to: a ban on aerial applications; the use of low-volatility formulations; restrictions on 

spray nozzle use to ensure larger droplets are applied; restrictions on boom height for pesticide 

applications; and for certain limited use areas, buffers and other application limitations based on 

wind speed and other factors specifically designed to prevent spray drift from having any effect 

on threatened or endangered plants (or obligate plants or critical habitat relied on by a small 

number of endangered species). These label restrictions, and/or any other measures imposed 

by EPA, will ensure that there is no effect on threatened and endangered species from the use 

of dicamba on DT soybean and DGT cotton. Furthermore, to provide growers with specific 

information for dicamba applications to dicamba-tolerant crops, Monsanto is implementing a 

robust stewardship program that will include a strong emphasis on grower and applicator 

training.

In lengthy and detailed submissions to EPA over the past two years, Monsanto has established 

the scientific predicate for its conclusions that these specific measures will preclude the dicamba 

applications at issue from having an effect on threatened or endangered species. Specifically, 

Monsanto has submitted the following reports on the potential impacts on threatened and 

endangered species of dicamba use over the top of DT soybean: 

 Determination of Dicamba Residue Decline in Forage after Application to 

Dicamba-Tolerant Soybean MON 87708 × MON 89788. Feb. 27, 2012

 Honegger, Overview for Plant Taxa, Dec. 20, 2012 [“Plant Overview”];

 Frank and Kemman, A County-Level Analysis for Plant Taxa, Dec. 20, 2012; 

 Carr and Leopold, Sub-County Proximity Analysis for Listed Plants: Part 1 of 2: 

Western U.S. States and Hawaii, Dec. 20, 2012; 
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 Carr and Leopold, Sub-County Proximity Analysis for Listed Plants: Part 2 of 2: 

Eastern U.S. States, Dec. 20, 2012; 

 Carr and Leopold, Sub-County Proximity Analysis for Listed Plants: Iowa, Apr 

4, 2013; 

 Wright, et. al, An Evaluation of Potential Exposure and Biological Effects, Jan. 

25, 2013; 

 Honegger, Overview of an Evaluation of Potential Exposure and Biological 

Effects, Mar. 12, 2013 [hereinafter “Overview”]; 

 Schuler, et. al, Refined Analysis for Terrestrial Animals, Mar. 12, 2013; 

 Frank and Kemman, A County-Level Analysis for Animal Taxa (2013 Update), 

Mar. 12, 2013; 

 Schuler, et. al., Indirect Effects Analysis for Terrestrial Animals, Apr. 4, 2013; 

 Honegger, Overview of Proposed Approach to Address the Potential for Offsite Movement from Use of Dicamba on Dicamba-Tolerant Soybeans, Aug. 7, 

2012; 

 Orr, et. al., Concordance of MON 54140 Buffer Distances Determined using 

Field Spray Drift Studies and AgDRIFT®, Mar. 12, 2013; 

 Wright, Potential Effects of MON 54140 on Soybean Plants when Applied at 

Low Application Rates in the Field, Aug. 7, 2012; 

 Orr, et. al., Summary of Investigations of the Potential for Off-Site Movement 

through the Air of the Herbicide MON 54140 Following Ground Applications, 

Jul. 17, 2012; and 

 Sall, et. al., Measurement of the Volatile Flux of Dicamba under Field 

Conditions using the Theoretical Profile Shape Method, April 22, 2013. 

In addition, Monsanto has submitted the following reports on the potential impacts on 

threatened and endangered species of dicamba use over the top of DGT cotton:

Honegger et al., An Evaluation of Potential Exposure and Biological Effects. October 

8, 2013.

Honegger, Overview of an Evaluation of Potential Exposure and Biological Effects to 

Animals October 8, 2013.

Carr and Orr, Potential Exposure and Effects for Listed Plants, October 8, 2013.

Schuler, et al., Indirect Effects Analysis for Terrestrial Animals, October 8, 2013.

Schuler, et al., Refined Analysis for Terrestrial Animals, October 8, 2013.
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Frank and Kemman, A County-Level Analysis for Animal Taxa, October 8, 2013. 

Frank and Kemman, A County-Level Analysis for Plant Taxa, October 8, 2013.

The reports describe the risk assessment process prescribed by EPA to carry out its particular 

duties with respect to the ESA, i.e., analyzing the risk of direct effects of dicamba to threatened 

and endangered species in association with DT soybean and DGT cotton cultivation. As 

described therein, for both TES animals and plants, Monsanto first conducted the type of 

screening-level analyses set forth in EPA’s Overview Document. Using the maximum use pattern 

set out in the proposed label at issue, which is currently pending before EPA, Monsanto 

estimated exposure of designated animal and plant taxa using current EPA environmental 

exposure models. Monsanto then utilized these conservative exposure estimates, in 

conjunction with effects values for species of designated taxa derived from toxicity tests 

meeting EPA quality standards, to calculate risk quotients (RQs). If the RQ value, calculated by 

dividing the estimated exposure by the appropriate toxicity value, was less than the Level of 

Concern (LOC) for TES in the designated taxa, Monsanto concluded that risks to a taxonomic 

category could be excluded from concern because of the conservative nature of the screeninglevel assessment assumptions and, therefore, that there would be no effect on the relevant 

threatened or endangered species. Monsanto undertook a similar analysis at the screening level 

to evaluate potential indirect effects on threatened and endangered species and potential effects 

on critical habitat, thereby enabling Monsanto to exclude from concern such effects on certain 

species. 

Again, following EPA’s Overview Document, Monsanto next conducted a more detailed, countylevel analysis for taxonomic groups (and associated listed species) that could not be excluded 

from concern at the screening level. This analysis identified: (i) all counties indicated as having 

soybean / cotton farms in the last three Ag. Census (1997, 2002, and 2007) as having 

“potential” for soybean production, and (ii) every endangered species within those counties in 

the taxonomic groups that had not been excluded from concern at the screening level. A “no 

effect” determination could then be made for species “co-occurrences” based on a number of 

exclusions (e.g., product property, habitat, not of concern, proximity, diet, and feeding) or on 

state or federally recognized protections. 

For animals, this analysis expressly recognized and took into account the fact that the animals at 

issue may move from location to location. Specifically, the feeding and diet exclusions for 

animals are based on inherent characteristics of the individual endangered species and are not in 

any way impacted by where the species is physically present. The “not of concern” designation 

is provided only where the species has not been reported in the county in the past 35 years, or 

where FWS does not include the county on the list of counties where the species is known or 

believed to occur in the county (or where the species has been delisted). The habitat exclusion 

applies only where the individual endangered species’ habitat is not suitable for agricultural 

production. Finally, the proximity exclusion only applies when land relevant for soybean 

production is not within a relevant species’ “home range” – i.e., the area within which the 

species lives and travels, based on information from FWS and other sources. 

For co-occurrences of listed plant species not excluded from concern based on the county level 

analysis, a refined sub-county analysis was undertaken to assess the proximity of reported 

species observations to relevant land use for soybean / cotton production. In addition, 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 309 of 946

mitigation measures were proposed, where necessary, to prevent effects on such plant species 

in certain use limitation areas. For more details on Monsanto’s ESA assessment for dicamba, 

see Appendix F to this Environmental Report. Based on these analyses, and any further 

analysis conducted by Monsanto and/or US EPA, U.S. EPA, who has the sole authority to 

authorize or regulate the use of dicamba, or any other herbicide, will be positioned to comply 

fully with its ESA obligations with respect to dicamba use on DT soybean and DGT cotton.

VII. CONSIDERATION OF EXECUTIVE ORDERS, STANDARDS, AND

TREATIES RELATING TO ENVIRONMENTAL IMPACTS

VII.A. EXECUTIVE ORDERS (EO) WITH DOMESTIC IMPLICATIONS 

The following EOs require consideration of the potential impacts of the Federal action to 

various segments of the population. 

EO 12898 (US-NARA, 2010), “Federal Actions to Address 

Environmental Justice in Minority Populations and Low-Income 

Populations,” requires Federal agencies to conduct their 

programs, policies, and activities that substantially affect human 

health or the environment in a manner so as not to exclude 

persons and populations from participation in or benefiting 

from such programs. It also enforces existing statutes to 

prevent minority and low-income communities from being 

subjected to disproportionately high and adverse human health 

or environmental effects. 

EO 13045, “Protection of Children from Environmental 

Health Risks and Safety Risks,” acknowledges that children 

may suffer disproportionately from environmental health and 

safety risks because of their developmental stage, greater 

metabolic activity levels, and behavior patterns, as compared to 

adults. The EO (to the extent permitted by law and consistent 

with the agency’s mission) requires each Federal agency to 

identify, assess, and address environmental health risks and 

safety risks that may disproportionately affect children. 

The No Action and Deregulation in Whole Alternatives were analyzed with respect to EO 

12898 and EO 13045. Neither alternative is expected to have a disproportionate adverse effect 

on minorities, low-income populations, or children. 

Available mammalian toxicity data associated with the MON 88701 DMO and PAT (bar) 

proteins establish the safety of DT soybean and DGT cotton and their products to humans, 

including minorities, low-income populations, and children who might be exposed to them 

through agricultural production and/or processing. No additional safety precautions would 

need to be taken. 

Based on the information submitted Monsanto, DT soybean and DGT cotton are 

agronomically, phenotypically, and biochemically comparable to conventional soybean and 

cotton except for the introduced DMOs (both DT soybean and DGT cotton) and PAT (bar) 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 310 of 946

(DGT cotton) proteins. The information provided in the petition indicates that the proteins, 

DMO and PAT (bar), expressed in DT soybean and/or DGT cotton are not expected to be 

allergenic, toxic, or pathogenic in mammals (USDA Petitions 10-188-01p and 12-185-01p). 

Also, FDA has completed biotechnology consultations on both proteins in the context of other 

food and feeds and indicated that they had no questions (Appendix I). 

Human toxicity has also been thoroughly evaluated by the EPA in its development of pesticide 

labels for both dicamba (U.S. EPA 2009a; d). Pesticide labels include use precautions and 

restrictions intended to protect workers and their families from exposures.72 APHIS assumes 

that growers will adhere to these legally-binding herbicide use precautions and restrictions. As 

discussed in Subsection IV.E, Human Health and Safety Impacts, the potential use of dicamba 

on DT soybean and dicamba and glufosinate on DGT cotton at the proposed application rates 

would be no more than that currently approved for other crops and found by the EPA not to 

have adverse impacts to human health when used in accordance with label instructions. It is 

expected that EPA and USDA ERS would monitor the use of DT soybean and DGT cotton to 

determine impacts on agricultural practices, such as chemical use, as they have done previously 

for herbicide-tolerant products. 

Based on these factors, a determination of nonregulated status of DT soybean and DGT cotton 

is not expected to have a disproportionate adverse effect on minorities, low-income 

populations, or children. 

The following executive order addresses Federal responsibilities regarding the introduction and 

effects of invasive species: 

EO 1311 (US-NARA, 2010),”Invasive Species,” states that 

Federal agencies take action to prevent the introduction of 

invasive species, to provide for their control, and to minimize 

the economic, ecological, and human health impacts that 

invasive species cause. 

Soybean and cotton are not listed in the U.S. as a noxious weed species by the Federal 

government nor are they listed as an invasive species by major invasive plant data bases. 

Cultivated soybean and cottonseed do not usually exhibit dormancy and requires specific 

environmental conditions to grow as a volunteer the following year (OECD 2000b; 2008). Any 

volunteers that may become established do not compete well with the planted crop and are 

easily managed using standard weed control practices. Soybean and cotton are not considered 

invasive species. Based on the information submitted by the applicant and assessed by APHIS, 

DT soybean and DGT cotton are agronomically, phenotypically, and biochemically comparable 

to conventional soybean and cotton except for the introduced DMO and PAT (bar) proteins. 

 

72 In order to approve a new use of a herbicide EPA must conclude that the herbicide, when used according to the label, 

does not pose an unreasonable adverse effect to humans or the environment, including agricultural workers and 

bystanders (e.g., farm families). Furthermore, the Worker Protection Standard requires the inclusion of precautionary 

language in the Agricultural Use Requirments box on the pesticide label. This language includes directions for the use 

and handling of personal protective equipment (PPE) to manage exposure to the worker and also serves to reduce 

exposure to the farm family from contaiminated clothing. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 311 of 946

Therefore, they would not be expected to have invasive characteristics different from 

commercially available soybean and cotton. 

The following executive order requires the protection of migratory bird populations: 

EO 13186 (US-NARA, 2010), “Responsibilities of Federal 

Agencies to Protect Migratory Birds,” states that Federal 

agencies taking actions that have, or are likely to have, a 

measurable negative effect on migratory bird populations are 

directed to develop and implement, within two years, a 

Memorandum of Understanding (MOU) with the Fish and 

Wildlife Service that shall promote the conservation of 

migratory bird populations. 

Migratory birds may be found in soybean and cotton fields. While soybean and cotton do not

meet the nutritional requirements for many migratory birds (Krapu et al., 2004), they may 

forage for insects and weed seeds found in and adjacent to soybean and cotton fields. As 

discussed in Sections IV.D.1.a and IV.D.2.a (Animal Communities) data submitted by the 

applicant has shown no difference in compositional and nutritional quality of DT soybean and 

DGT cotton compared with other GE or non-GE soybean and cotton, apart from the 

presence of the introduced proteins. DT soybean and DGT cotton are not expected to be 

allergenic, toxic, or pathogenic in mammals. The expressed proteins in DT soybean and DGT 

cotton have a history of safe consumption in the context of other food and feeds. The FDA 

has completed its food safety consultation on the MON 87708 DMO protein in DT soybean 

and the MON 88701 DMO and PAT (bar) protein in DGT cotton (Appendix I). Based on 

APHIS’ assessment of DT soybean and DGT cotton, it is unlikely that a determination of 

nonregulated status of DT soybean and DGT cotton would have a negative effect on migratory 

bird populations. The environmental effects associated with dicamba are included in the EPA 

RED for the herbicide (U.S. EPA 2009a; d). Testing indicates that dicamba, when used as 

directed by the U.S. EPA label, does not pose an unreasonable risk of adverse effects to birds 

(U.S. EPA 2009a; d). Based on these factors, it is unlikely that the determination of 

nonregulated status of DT soybean and DGT cotton would have a negative effect on migratory 

bird populations. 

VII.B. INTERNATIONAL IMPLICATIONS

EO 12114 (US-NARA, 2010), “Environmental Effects Abroad of Major Federal Actions,”

requires Federal officials to take into consideration any potential environmental effects outside 

the U.S., its territories, and possessions that result from actions being taken. 

Significant environmental impacts outside the U.S. are not expected in the event of a 

determination of nonregulated status of DT soybean and DGT cotton. All existing national and 

international regulatory authorities and phytosanitary regimes that currently apply to 

introductions of new soybean and cotton cultivars internationally apply equally to those 

covered by an APHIS determination of nonregulated status under 7 CFR part 340. 

Any international trade of DT soybean and/or DGT cotton subsequent to a determination of 

nonregulated status would be fully subject to national phytosanitary requirements and be in 

accordance with phytosanitary standards developed under the International Plant Protection 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 312 of 946

Convention (IPPC) (IPPC, 2010). The purpose of the IPPC “is to secure a common and 

effective action to prevent the spread and introduction of pests of plants and plant products 

and to promote appropriate measures for their control” (IPPC, 2010). The protection it 

affords extends to natural flora and plant products and includes both direct and indirect 

damage by pests, including weeds. 

The IPPC establishes a standard for the reciprocal acceptance of phytosanitary certification 

among the nations that have signed or acceded to the Convention (172 countries as of March 

2010). In April 2004, a standard for Pest Risk Analysis (PRA) of living modified organisms 

(LMOs) was adopted at a meeting of the governing body of the IPPC as a supplement to an 

existing standard, International Standard for Phytosanitary Measure No. 11 (ISPM-11, Pest Risk 

Analysis for Quarantine Pests). The standard acknowledges that all LMOs will not present a 

pest risk and that a determination needs to be made early in the PRA for importation as to 

whether the LMO poses a potential pest risk resulting from the genetic modification. APHIS 

pest risk assessment procedures for genetically engineered organisms are consistent with the 

guidance developed under the IPPC. In addition, issues that may relate to commercialization 

and transboundary movement of particular agricultural commodities produced through The 

Cartagena Protocol on Biosafety is a treaty under the United Nations Convention on Biological 

Diversity (CBD) that established a framework for the safe transboundary movement, with 

respect to the environment and biodiversity of LMOs, which include those modified through 

biotechnology. The Protocol came into force on September 11, 2003, and 160 countries are 

Parties to it as of December 2010 (CBD, 2010). Although the U.S. is not a party to the CBD, 

and thus not a party to the Cartagena Protocol on Biosafety, U.S. exporters will still need to 

comply with those regulations that importing countries which are Parties to the Protocol have 

promulgated to comply with their obligations. The first intentional transboundary movement 

of LMOs intended for environmental release (field trials or commercial planting) will require 

consent from the importing country under an advanced informed agreement (AIA) provision, 

which includes a requirement for a risk assessment consistent with Annex III of the Protocol 

and the required documentation. LMOs imported for food, feed, or processing (FFP) are 

exempt from the AIA procedure, and are covered under Article 11 and Annex II of the 

Protocol. Under Article 11, Parties must post decisions to the Biosafety Clearinghouse 

database on domestic use of LMOs for FFP that may be subject to transboundary movement. 

To facilitate compliance with obligations to this protocol, the U.S. Government has developed 

a website that provides the status of all regulatory reviews completed for different uses of 

bioengineered products (NBII, 2010). These data will be available to the Biosafety 

Clearinghouse. 

APHIS continues to work toward harmonization of biosafety and biotechnology consensus 

documents, guidelines, and regulations, including within the North American Plant Protection 

Organization (NAPPO), which includes Mexico, Canada, and the U.S., and within the OECD. 

NAPPO has completed three modules of the Regional Standards for Phytosanitary Measures 

(RSPM) No. 14, Importation and Release into the Environment of Transgenic Plants in NAPPO Member 

Countries (NAPPO, 2009). 

APHIS also participates in the North American Biotechnology Initiative (NABI), a forum for 

information exchange and cooperation on agricultural biotechnology issues for the U.S., 

Mexico, and Canada. In addition, bilateral discussions on biotechnology regulatory issues are 

held regularly with other countries including Argentina, Brazil, Japan, China, and Korea. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 313 of 946

VII.C. IMPACTS ON UNIQUE CHARACTERISTICS OF GEOGRAPHIC AREAS

A determination of nonregulated status of DT soybean and DGT cotton is not expected to 

impact unique characteristics of geographic areas such as park lands, prime farmlands, wetlands, 

wild and scenic areas, or ecologically critical areas. 

Monsanto has presented results of agronomic field trials for DT soybean and DGT cotton 

(Appendix G). The results of these field trials demonstrate that there are no differences in 

agronomic practices in DT soybean and DGT cotton when compared to commercially available 

soybean and cotton. The common agricultural practices that would be carried out in the 

cultivation of DT soybean and DGT cotton are not expected to deviate from current practices, 

including the use of EPA-registered pesticides. There are no proposed major ground 

disturbances; no new physical destruction or damage to property; no alterations of property, 

wildlife habitat, or landscapes; and no prescribed sale, lease, or transfer of ownership of any 

property. This action is limited to a determination of nonregulated status of DT soybean and 

DGT cotton. This action would not convert land use to nonagricultural use and, therefore, 

would have no adverse impact on prime farmland. Standard agricultural practices for land 

preparation, planting, irrigation, and harvesting of plants would be used on agricultural lands 

planted DT soybean and DGT cotton, including the use of EPA-registered pesticides. The 

adherence to EPA label use restrictions for all pesticides is expected to mitigate potential 

impacts to the human environment. With regard to pesticide use, a determination of 

nonregulated status of DT soybean and DGT cotton is likely to result in changes to the use of 

dicamba on soybean and cotton. The potential changes in herbicide use, including application 

rates and annual maximum allowable applications, are discussed in Section IV.A. Monsanto has 

submitted applications to EPA to provide for this change in use for dicamba on DT soybean 

and DGT cotton (there is no expected change in glufosinate use from the currently approved 

application rate for cotton). APHIS assumes that any new EPA label would provide for label 

use restrictions intended to mitigate potential impacts to the human environment, including 

potential impacts to unique geographic areas. As noted above, APHIS further assumes that the 

grower will closely adhere to EPA label use restrictions for all pesticides. 

In 2009, the EPA completed a reregistration analysis for dicamba which considered human 

health risk and ecological risks associated with potential exposure to dicamba in multiple 

pathways (U.S. EPA 2009a; d). Although some risks were identified, the EPA determined that 

these risks could be mitigated by modifying the approved label application rates and spray 

droplet size (U.S. EPA 2005c). The EPA has also evaluated the potential effect of dicamba on 

salmon in eleven areas of California and Southern Oregon73 in response to the consent 

agreement reached in the Washington Toxics lawsuit.74 The conclusion of EPA’s risk 

assessment is as follows: 

 

73 These areas are called Evolutionarily Significant Units based on the salmonid populations present in these areas.

74 Washington Toxics Coalition v. Environmental Protection Agency, 413 F.3d 1024 (9th Cir. 2005).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 314 of 946

“Regardless of the specific dicamba compounds, I conclude that dicamba compounds 

with currently registered uses will have “no effect” on listed Pacific salmon and steelhead and 

their critical habitat...” (U.S. EPA 2003).

Glufosinate-ammonium was first registered for home use with the EPA in 1993 (OSTP, 2001). 

It is currently labeled under the trade name Ignite

®

280 SL by Bayer CropScience LP (Bayer 

Crop Science 2007). The EPA is currently conducting a Registration Review for glufosinate 

with a forthcoming final decision scheduled in 2013 (U.S. EPA 2008b). The Agency plans to 

conduct a comprehensive ecological risk assessment, including an endangered species 

assessment, for all glufosinate-ammonium uses. The Agency has requested additional aquatic 

nonvascular plant data to evaluate the extent of risk to aquatic plants imposed by the 

application of glufosinate-ammonium. The EPA’s Final Work Plan for Registration Review 

(U.S. EPA 2008b) states: 

“The planned ecological risk assessment will allow the Agency to determine whether 

glufosinate-ammonium use has “no effect” or “may affect” federally listed threatened or 

endangered species (listed species) or their designated critical habitat. If the assessment 

indicates that glufosinate-ammonium “may affect” a listed species or its designated critical 

habitat, the assessment will be refined. The refined assessment will allow the Agency to 

determine whether use of glufosinate-ammonium is “likely to adversely affect” the species or 

critical habitat or “not likely to adversely affect” the species or critical habitat. When an 

assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical 

habitat, the Agency will consult with the U.S. Fish and Wildlife Service and National Marine 

Fisheries Service (the Services), as appropriate.”

Submittals to this analysis can be found at the Regulations.gov website under docket 

designation EPA-HQ-OPP-2008-0190. Labeled uses of glufosinate are approved pending the 

outcome of the EPA’s ecological risk analysis. 

Based on these findings, including the assumption that label use restrictions are in place to 

protect unique geographic areas and that those label use restrictions are adhered to, a 

determination of nonregulated status DT soybean and DGT cotton is not expected to impact 

unique characteristics of geographic areas such as park lands, prime farm lands, wetlands, wild 

and scenic areas, or ecologically critical areas. 

VII.D. NATIONAL HISTORIC PRESERVATION ACT (NHPA) OF 1966 AS 

AMENDED

The NHPA of 1966 and its implementing regulations (36 CFR 800) require Federal agencies to: 

(1) determine whether activities they propose constitute “undertakings” that 

have the potential to cause effects on historic properties, and (2) if so, to 

evaluate the effects of such undertakings on such historic resources and consult 

with the Advisory Council on Historic Preservation (i.e., State Historic 

Preservation Office, Tribal Historic Preservation Officers), as appropriate. 

APHIS’ proposed action, a determination of nonregulated status of DT soybean and DGT

cotton is not expected to adversely impact cultural resources on tribal properties. Any farming 

activity that may be taken by farmers on tribal lands would only be conducted at the tribe’s 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 315 of 946

request; APHIS’ Preferred Alternative would have no impact on districts, sites, highways, 

structures, or objects listed in or eligible for listing in the National Register of Historic Places, 

nor would it likely cause any loss or destruction of significant scientific, cultural, or historical 

resources. This action is limited to a determination of non-regulated status of DT soybean and 

DGT cotton. APHIS’ proposed action is not an undertaking that may directly or indirectly 

cause alteration in the character or use of historic properties protected under the NHPA. In 

general, common agricultural activities conducted under this action do not have the potential to 

introduce visual, atmospheric, or noise elements to areas in which they are used that could 

result in effects on the character or use of historic properties. For example, there is potential 

for increased noise on the use and enjoyment of a historic property during the operation of 

tractors and other mechanical equipment close to such sites. A built-in mitigating factor for 

this issue is that virtually all of the methods involved would only have temporary effects on the 

audible nature of a site and can be ended at any time to restore the audible qualities of such 

sites to their original condition, with no further adverse effects. Additionally, these cultivation 

practices are already being conducted throughout the soybean production regions. The 

cultivation of DT soybean and DGT cotton is not expected to change any of these agronomic 

practices that would result in an adverse impact under the NHPA. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 316 of 946

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Appendix A: Dicamba Herbicide Usage, Herbicide Displacement, and Comparative 

Analysis of Alternative Registered Herbicides
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TABLE OF CONTENTS

A.1. Introduction and Overview................................................................................................................. 362

A.2. Background on Dicamba Use in the U.S. ......................................................................................... 363

A.3. Impact of DT Soybean Deregulation ................................................................................................ 366

A.3.1. Impact of DT Soybean Deregulation on Dicamba Use................................................. 366

A.3.2. Projections of dicamba use on DT Soybean.................................................................... 366

A.3.3. Benefits of DT Soybean for Weed Management ............................................................ 370

A.3.4. Herbicide Use Trends: Impact of DT Soybean on future herbicide use ..................... 376

A.3.4.1. Materials and Methods ....................................................................................... 376

A.3.4.2. Analysis of PRE Soybean Herbicide Use from 2002-2011........................... 384

A.3.4.3. Analysis of POST Soybean Herbicide Use from 2002-2011 ........................ 386

A.3.4.4. Projected Dicamba Use (TAT and Total Pounds) on DT 

Soybean.................................................................................................................. 388

A.3.5. Displacement of Other Non-Glyphosate Herbicides by Dicamba Use 

Following Deregulation of DT Soybean ........................................................................ 390

A.3.5.1. Materials and Methods ....................................................................................... 390

A.3.5.2. Analysis of Displacement of Other Non-Glyphosate Herbicides 

by Dicamba Use Following Deregulation of DT Soybean ............................ 393

A.3.6. Net Impact of DT Soybean on Overall Herbicide Use.................................................. 397

A.3.7. Comparative Analysis of Dicamba and Alternative Soybean Herbicides.................... 400

A.3.7.1. Introduction ......................................................................................................... 400

A.3.7.2. Properties of Alternative Herbicide Products................................................. 404

A.3.7.3. Comparison of Dicamba Use in the Dicamba-Tolerant Soybean 

System to Alternative Herbicides....................................................................... 432

A.4. Impact Of DGT Cotton Deregulation.............................................................................................. 446

A.4.1. Impact of DGT Cotton Deregulation on Dicamba Usage............................................ 446

A.4.1.1. Overview............................................................................................................... 446

A.4.1.2. Materials and Methods ....................................................................................... 450
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A.4.1.3. Analysis of PRE Cotton Herbicide Use From 2002-2011 ............................ 454

A.4.1.4. Analysis of POST Cotton Herbicide Use From 2002-2011 ......................... 458

A.4.1.5. Projected Dicamba Use (TAT and Total Pounds) on DGT 

Cotton .................................................................................................................... 460

A.4.2. Displacement of Other Non-Glyphosate Herbicides by Dicamba Use 

Following Deregulation of DGT Cotton ....................................................................... 463

A.4.2.1. Materials and Methods ....................................................................................... 463

A.4.2.2. Analysis of Displacement of Other Non-Glyphosate Herbicides 

by Dicamba Use Following Deregulation of DGT Cotton ........................... 466

A.4.3. Net Impact of DGT Cotton on Overall Herbicide Use ................................................ 471

A.4.4. Comparative Analysis of Dicamba and Alternative Cotton Herbicides ...................... 474

A.4.4.1. Background .......................................................................................................... 474

A.4.4.2. Alternative Registered Herbicides – Comparative Analysis.......................... 482

A.5. Summary and Conclusion.................................................................................................................... 504
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TABLES AND FIGURES

Table A-1. Dicamba Use in All Labeled Crops from 1990 to 20111.................................................... 364

Table A-2. Dicamba-Treated Acres and Amounts Applied to Labeled Crops and Uses 

in 20111.............................................................................................................................................. 365

Table A-3. Dicamba Applications – Average Number and Rates to Labeled Crops1....................... 365

Table A-4. Anticipated Weed Management Recommendations for DT Soybean 

Combined with Glyphosate-Tolerant Soybean 1......................................................................... 367

Table A-5. Projected Dicamba Use on DT Soybean.............................................................................. 369

Table A-6. Common Broadleaf Weed Responses to Preplant Burndown Herbicides...................... 372

Table A-7. Common Broadleaf Weed Responses to Dicamba Compared to Labeled 

Postemergence Herbicides in Soybean Production.................................................................... 373

Table A-8. Herbicide Use in Soybean Use in the U.S. in 20121............................................................ 374

Table A-9. Non-Glyphosate Herbicides Used in Glyphosate-Tolerant Soybeans from 

2002 to 2011a.................................................................................................................................... 378

Table A-10. Total Acres Treated (TAT) for PRE Applications – Soybean ........................................ 379

Table A-11: Total Acres Treated (TAT) for POST applications – Soybean....................................... 381

Figure A-1. Regression model and predictions for PRE non-glyphosate soybean 

herbicides.......................................................................................................................................... 383

Figure A-2. Regression model and predictions for POST non-glyphosate soybean 

herbicides.......................................................................................................................................... 383

Table A-12. Base acres and average number of applications for PRE segment –

Soybeana............................................................................................................................................ 385

Table A-13. Base acres and average number of applications for POST segment –

Soybeana............................................................................................................................................ 387

Table A-14. Anticipated Total Acres Treated (TAT) for PRE and POST applications of 

dicamba on DT Soybean ................................................................................................................ 389

Table A-15. Projected Total Acres Treated (TAT) for PRE herbicides most likely to be 

displaced by dicamba – Soybean ................................................................................................... 391

Table A-16. Projected Total Acres Treated (TAT) for POST herbicides most likely to 

be displaced by dicamba – Soybean.............................................................................................. 392
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Table A-17. Projected Total Pounds for PRE herbicides most likely to be displaced by 

dicamba – Soybean.......................................................................................................................... 395

Table A-18. Projected Total Pounds for POST herbicides most likely to be displaced 

by dicamba – Soybean..................................................................................................................... 396

Table A-19. Net impact of Dicamba-Tolerant soybean on overall herbicide use.............................. 399

Table A-20. Common Weeds in Soybean Production: Midwest Region............................................ 402

Table A-21. Common Weeds in Soybean Production: Southeast Region.......................................... 403

Table A-22. Common Weeds in Soybean Production: Eastern Coastal Region ............................... 403

Table A-23. Ten Most Widely Used Alternative Herbicides in U.S. Soybean Production 

in 2012............................................................................................................................................... 404

Table A-24. Dicamba and Alternative Registered Soybean Herbicides............................................... 405

Table A-25. Active Ingredients Contained in Alternative Herbicides.................................................. 411

Table A-26. Human Health Risk Parameters for Alternative Herbicides............................................ 414

Table A-27. Aquatic Toxicity Parameters for Fish and Aquatic Invertebrates for 

Alternative Herbicides .................................................................................................................... 419

Table A-28. Aquatic Toxicity Parameters for Aquatic Plants for Alternate Herbicide 

Active Ingredients............................................................................................................................ 423

Table A-29. Herbicide Efficacy Comparison: Herbicide Resistant Weeds and Hard-toControl Weeds in Soybean............................................................................................................. 429

Table A-30. Summary of Comparative Analysis of Dicamba and Alternative Herbicides 

Used in Soybean............................................................................................................................... 433

Table A-31. Planting Restrictions (months) for Alternative Herbicide Products............................... 441

Table A-32 Soybean Production in the U.S., 1999 – 20121................................................................... 445

Table A-33. Herbicide Applications Registered for Use in Cotton in 20111...................................... 448

Table A-34. Non-Glyphosate Herbicides Used in Cotton from 2002-2011 ........................................ 451

Table A-35. Total Treated Cotton Acres for PRE Herbicide Applications1........................................ 452

Table A-36. Total Treated Cotton Acres for POST Herbicide Applications1..................................... 453

Figure A-3. Average Number of Preplant/Preemergence and Postemergence Nonglyphosate herbicide applications in cotton 2002-2011 ............................................................. 455
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 361 of 946

Table A-37. Total Treated Cotton Acres for PRE Herbicide Applications1........................................ 456

Table A-38. Cotton Base Acres and Average Number of PRE and POST Herbicide 

Applications in Cotton from 2002-20111.................................................................................... 457

Table A-39. Total Treated Cotton Acres for POST Herbicide Applications1..................................... 459

Table A-40. Estimated Dicamba Total Acres Treated at Peak Dicamba Use on DGT 

Cotton ............................................................................................................................................... 461

Table A-41. Estimated Dicamba Total lbs a.i. at Peak Dicamba Use on DGT Cotton..................... 462

Table A-42. Projected Total Acres Treated for PRE Cotton Herbicides Likely to be 

Displaced by Dicamba .................................................................................................................... 464

Table A-43. Projected lbs a.i. for PRE Cotton Herbicides Likely to be Displaced by 

Dicamba ............................................................................................................................................ 465

Table A-44. Projected Total Acres Treated for POST Cotton Herbicides Likely to be 

Displaced by Dicamba .................................................................................................................... 468

Table A-45. Projected lbs a.i. for POST Cotton Herbicides Likely to be Displaced by 

Dicamba ............................................................................................................................................ 470

Table A-46. Net Impact of DGT Cotton on Overall Herbicide Use.................................................... 473

Table A-47. Dicamba and Alternative Registered Cotton Herbicides .................................................. 475

Table A-48. Dicamba Compared to Active Ingredients Contained in Alternative 

Herbicide Products.......................................................................................................................... 480

Table A-49. Human Health Risk Parameters for Acute Exposure to Dicamba and 

Alternate Herbicide Products ........................................................................................................ 484

Table A-50. Human Health Risk Parameters for Chronic Exposure to Dicamba and 

Alternative Herbicides .................................................................................................................... 487

Table A-51. Aquatic Toxicity for Fish and Aquatic Invertebrates from Acute Exposure................ 490

Table A-52. Aquatic Toxicity Parameters for Aquatic Plants for Dicamba and Alternate 

Herbicide Active Ingredients......................................................................................................... 492

Table A-53. Groundwater and Leaching Parameters for Dicamba and Alternate Active 

Ingredients........................................................................................................................................ 495

Table A-54. Summary of Comparative Analysis of Dicamba and Alternative Herbicides 

Used in Cotton................................................................................................................................. 498

Table A-55. Alternative Herbicide Agronomic Risk Measures............................................................. 500
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 362 of 946

Table A-56. Summary of Dicamba Reduced Risk Opportunities vs. Alternative 

Herbicides......................................................................................................................................... 503

A.1. INTRODUCTION AND OVERVIEW

Herbicides have provided soybean and cotton growers with the most cost-effective way to 

manage weeds. Herbicides are used on 98% of soybean acres and more than 35 different 

herbicides are approved for use in soybean cultivation. Herbicides are also used on 99% of 

cotton acres and more than 45 different herbicides have been used in cotton from 2002-2011. 

Glyphosate is the most widely used soybean and cotton herbicide, and it is used on 97% of 

soybean acres and 91% of cotton acres (USDA-NASS, 2007; Monsanto, 2012). 

Growers base their herbicide decisions on a number of factors including weed species, tillage 

practices, herbicide price and efficacy, and weed resistance considerations. Public and private 

sector weed scientists have recommended the use of multiple herbicide modes-of-action in 

agricultural crop production to provide broad spectrum weed control, to delay the evolution 

and development of weed resistance, and to control weeds that are already resistant to a 

particular herbicide or herbicide mode-of-action. Recent recommendations for the use of 

multiple modes-of-action in mixtures, sequences, and/or rotation are based on studies that 

have shown resistance can be mitigated, contained, and managed through good management 

practices (Beckie and Reboud 2009; Neve et al., 2011). In particular, simultaneously using two 

herbicides with different modes-of-action significantly reduces the probability of weeds 

developing resistance to either or both herbicides (Beckie and Reboud, 2009; Powles et al., 

1996). Consequently, soybean and cotton growers have increasingly incorporated herbicides 

with other modes-of-action (i.e., non-glyphosate herbicides) into their weed management 

practices. Current market research has demonstrated that growers are adopting weed 

management practices that utilize multiple herbicide modes-of-action (Givens et al., 2009; 

Hurley et al., 2009; Price et al., 2012). 

The use of non-glyphosate herbicides is expected to continue to grow. In fact, it is reasonable 

to expect that the use of non-glyphosate herbicides with other modes-of-action will continue 

with or without the deregulation of dicamba-tolerant soybean, designated as event MON 87708 

(“DT soybean”), or dicamba- and glufosinate-tolerant cotton, designated as event MON 88701( 

“DGT cotton”). However, the deregulation of DT soybean and DGT cotton will provide 

growers with the ability to integrate new uses of dicamba into soybean and cotton weed 

management systems that include other herbicides and/or mechanical and cultural practices, all 

of which contribute to mitigating the evolution and development of herbicide resistance.

Recent publications by Mortensen et al. (2012) and Benbrook (2012) suggest that the 

commercialization of dicamba-tolerant soybean and associated use of dicamba will only be 

additive to current herbicide use. Additionally, Mortensen claims that this use could result in a 

“profound” increase in overall herbicide use (Mortensen et al., 2012). Contrary to these 

publications, the available data support the conclusion that dicamba will displace some 

herbicides currently used in soybean and cotton cultivation, and that the increase in total 

herbicide use when DT soybean and DGT cotton are commercialized will be consistent with 

weed resistance best management practices being recommended by public and private sector 

weed scientists with the desire to maintain optimum crop yields. 
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A.2. BACKGROUND ON DICAMBA USE IN THE U.S.

Dicamba was approved by the U.S. Environmental Protection Agency (EPA) for agricultural 

uses in 1967 (EPA 2009b). Dicamba is formulated as a stand-alone herbicide product and 

marketed by several companies under various trade names—including Banvel®, Clarity®, 

Diablo®, Rifle®, and Sterling®—that are various salt formulations of dicamba. These dicamba 

products can be tank mixed with one or more active ingredients depending on the treated crop. 

For example, Clarity®can be tank mixed with over 75 herbicide products in labeled crops. 

Additionally, dicamba is formulated as a registered premix product with one or more other 

herbicide active ingredients such as 2,4-D, atrazine, diflufenzopyr, glyphosate, halosulfuron, 

metsulfuron, nicosulfuron, primsulfuron, rimsulfuron, and triasulfuron. Dicamba herbicide 

(e.g., Clarity®– diglycolamine [DGA] salt of dicamba) is currently labeled for weed control in 

soybean, corn, cotton, sorghum, wheat, barley, oats, millet, pasture, rangeland, asparagus, 

sugarcane, turf, grass grown for seed, conservation reserve programs, and fallow croplands. 

Table A-1 provides a summary of dicamba-treated acres (i.e., crop acreage that has dicamba 

applied to it) and the amount of dicamba acid equivalent applied for all labeled crops each year 

from 1990 through 2011. Dicamba-treated acreage has ranged from 17.4 to 36.3 million acres 

during this period. Usage of dicamba peaked during the period of 1994 through 1997 (1994 

being the peak year, with 36.3 million acres treated with 9.4 million pounds of dicamba). After 

1994, the use of dicamba steadily declined through 2006 to 17.4 million treated acres with 2.7 

million pounds used, due to the competitive market introductions of sulfonylurea herbicides 

(chlorsulfuron, metsulfuron-methyl, and thifensulfuron-methyl) in wheat, new broadleaf 

herbicide active ingredients in corn, and glyphosate-tolerant corn. However, dicamba-treated 

acres have increased by as much as 4.0 million acres since 2006. Most of the increase in 

dicamba-treated acres has occurred in fallow, pastureland, sorghum, and cotton (Monsanto, 

2012). Dicamba-treated acres have increased in cotton, in particular, because it is a common 

preplant herbicide recommendation for glyphosate-resistant marestail (horseweed) and Palmer 

amaranth in the Midsouth region (McClelland et al., 2006). Approximately 25.3 million acres of 

crops were treated with dicamba in 2011 (see Table A-2 for a summary of the dicamba-treated 

acres by crop in 2011). Based on USDA-NASS (2005, 2007, 2010, 2011, and 2012) statistics, 

dicamba application rates ranged from 0.07 to 0.24 pounds per acre with the average number of 

applications ranging from 1 to 1.9 applications per cropping season. Dicamba rates are lowest 

in barley, wheat and oats, where typically more than one application is made in these crops per 

cropping season (see Table A-3)
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Table A-1. Dicamba Use in All Labeled Crops from 1990 to 20111

Year

Treated Acres

(000,000 acres)

Dicamba (a.e.)

(000,000 lbs)

1990 26.8 6.7

1991 24.5 6.3

1992 30.3 7.4

1993 27.7 7.0

1994 36.3 9.4

1995 34.3 8.7

1996 33.3 8.2

1997 33.1 8.6

1998 32.2 8.0

1999 29.8 6.3

2000 29.4 5.4

2001 30.6 5.4

2002 29.4 5.0

2003 27.1 4.3

2004 22.3 3.9

2005 21.3 3.4

2006 17.4 2.7

2007 18.6 2.7

2008 20.2 2.7

2009 21.5 3.1

2010 20.3 3.3

2011 25.3 3.8

1 Source is Monsanto (2012).

Shaded bar indicates the year with maximum dicamba-treated acres.
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Table A-2. Dicamba-Treated Acres and Amounts Applied to Labeled Crops and Uses 

in 20111

Crop

Total Crop

Acres (000)

DicambaTreated 

Acres (000)

% U.S. 

DicambaTreated 

Acres2

% Crop 

Acres 

Treated with 

Dicamba3 

Dicamba 

(a.e.)

(000 lbs)

Asparagus 29 2 0.01 NA <1

Barley 2,460 80 0.3 3.2 6

Corn 92,146 10,880 43.0 10.3 1,531

Cotton 14,533 1,416 5.6 9.6 364

Fallow 14,899 3,966 15.7 18.7 597

Pastureland 95,532 2,009 7.9 2.0 438

Sorghum 5,315 1,316 5.2 18.1 206

Soybean 74,835 872 3.4 1.2 233

Sugarcane 825 163 0.6 15.6 36

Wheat, all 53,223 4,532 17.9 7.4 418

All other uses NA 65 0.3 NA 9

Total 25,301 100.0 3,837

NA denotes not applicable.

1 Source is Monsanto (2012).

2 The percentage of the total dicamba-treated acres for all labeled crops and uses.

3 Percentages calculated from crop acres treated with dicamba (data not shown).

Table A-3. Dicamba Applications – Average Number and Rates to Labeled Crops1

Crop

# of Dicamba 

Applications

Rate of Dicamba 

per Application

Rate of Dicamba 

per Crop Year

Corn 1.2 0.209 0.249

Cotton 1.0 0.244 0.244

Sorghum 1.9 0.159 0.298

Soybean 1.0 0.223 0.223

Barley 1.0 0.112 0.112

Wheat, spring - 0.110 0.113

Wheat, winter 1.7 0.149 0.247

Oats 1.00 0.066 0.066

1USDA-NASS, 2005 (oats), 2007 (cotton), 2010 (corn), 2011 (barley & sorghum), 2012 

(soybean & wheat)
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A.3. IMPACT OF DT SOYBEAN DEREGULATION 

A.3.1. Impact of DT Soybean Deregulation on Dicamba Use

Monsanto has developed DT soybean to offer growers an expanded use of the herbicide 

dicamba in soybean production. DT soybean will facilitate a wider window of dicamba 

application in soybean, allowing preemergence application up to the day of crop emergence 

(cracking) and in-crop postemergence applications through the R1/R2 growth stage. DT 

soybean will be combined with glyphosate-tolerant soybean utilizing traditional breeding 

techniques. The combination of herbicide-tolerance traits will allow the pre- and 

postemergence use of both dicamba and glyphosate herbicides in a diversified weed 

management program to control a broad spectrum of grass and broadleaf weed species 

(Johnson et al., 2010). Increasing postemergence herbicide options is important, especially in 

conservation tillage situations, where the performance consistency of postemergence herbicides 

has generally been greater than that of soil active residual products. Dicamba will offer an 

effective control option for glyphosate-resistant broadleaf weed species, namely marestail, 

common ragweed, giant ragweed, palmer pigweed, and waterhemp, as well as improve control 

of glyphosate’s hard-to-control broadleaf weeds (e.g., common lambsquarters, hemp sesbania, 

morningglory species, nightshade, Pennsylvania smartweed, prickly sida ̧ and wild buckwheat) 

(Johnson et al., 2010). Dicamba will also offer an effective control option for broadleaf species 

resistant to ALS and PPO chemistries. In the case of PPO resistance, a primary dicamba 

benefit will be to provide options for delaying the further spread of PPO resistant Amaranthus

species (University of Tennessee, 2010).

A.3.2. Projections of dicamba use on DT Soybean 

Current labeled uses of dicamba in soybean are limited to early preplant and late postemergence 

(preharvest) applications. Significant planting restrictions exist in soybean for preplant 

applications of dicamba, including a maximum application rate of 0.5 lbs a.e. per acre, a 28-day 

interval between application and planting soybean, and a minimum of one inch of rainfall must 

occur before planting soybean to avoid soybean injury. Monsanto has submitted an application 

to U.S. EPA to amend Registration Number 524-582, a low volatility DGA salt formulation, to 

remove all preemergence planting restrictions (intervals and rainfall) and to allow in-crop 

postemergence dicamba applications to DT soybean through the R1/R2 growth stage. Once 

approved, growers would be authorized to apply dicamba alone or in mixtures with glyphosate 

or other herbicides for preplant or in-crop postemergence applications on DT soybean. 

Dicamba would be authorized to be applied preemergence up to crop emergence as a single 

application or split applications up to a total of 1.0 lb a.e. per acre, and up to two 

postemergence applications up to 0.5 lb a.e. per acre each through the R1/R2 growth stage of 

soybean. The maximum annual application rate of dicamba on DT soybean is 2.0 lb dicamba 

a.e. per acre. 

Furthermore, consistent with recommendations by academics and weed scientists, Monsanto 

will recommend the use of a third herbicide mode-of-action with soil residual activity as part of 

a comprehensive weed resistance management program to assure that at least two effective 

modes-of-action are always used in the cultivated soybean field. A summary of the anticipated 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 367 of 946

weed control recommendations for the combined DT soybean and glyphosate-tolerant soybean 

system is provided in Table A-4.

In 2010, Monsanto conducted an informal survey of weed scientists across the country to 

estimate the number of crop acres with glyphosate resistant weed populations. Based upon this 

survey it was estimated that approximately 14-16 million acres of planted row-crops (i.e. corn, 

soybeans, cotton) had populations of glyphosate resistant weeds. Of these acres, the majority 

of acres (~ 10 million) are infested with glyphosate resistant marestail populations where a 

preplant application of dicamba and glyphosate described above will be effective for control.

The remainder of resistant acres (~5 million) have resistant Ambrosia (common and giant 

ragweed) and Amaranthus (palmer pigweed and water hemp,) species present. A conservative 

estimate of 5 million resistant acres is assumed for this assessment, which overestimates current 

resistant acres in soybean producing areas and also accounts for potential increases in resistant 

acres because not all resistant crop acres would be planted to soybean in any given year.

Table A-4. Anticipated Weed Management Recommendations for DT Soybean 

Combined with Glyphosate-Tolerant Soybean 1

Application 

Timing

Conventional Tillage2 Conservation Tillage 2

(No-till or reduced till)

No GR 

Weeds

GR Weeds or Suspected 

GR Weeds No GR 

Weeds

GR Weeds or Suspected 

GR Weeds

Option 13 Option 24 Option 13 Option 24

Preemergence 

(burndown, at 

planting) 5

Residual Residual Residual

Residual

+

Glyphosate

+

Dicamba

Residual

+

Glyphosate

+

Dicamba

Residual

+

Glyphosate

+

Dicamba

Postemergence 1 

(V1-V3)

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Postemergence 2

(V4-R2) ---

Glyphosate

+

Dicamba

--- ---

Glyphosate

+

Dicamba

---

1 The anticipated use patterns represent a high-end estimate for predicting dicamba use associated with DT 

soybean integrated with the glyphosate-tolerant soybean system. Actual weed control practices by growers will 

vary depending on the specific weed spectrum and agronomic situation of the individual soybean field, 

specifically dicamba use could be lower especially for the preemergence and second postemergence applications.

2 Average rate for dicamba is 0.38 pound a.e. per acre except for fields with glyphosate resistant (GR) species 

where a 0.5 pound a.e. per acre postemergence application rate will be recommended. In some situations, the 

second postemergence application may not be needed. See Section III.A.1 for additional information 

supporting the anticipated use pattern.

3 Option 1 would be used for more aggressive glyphosate resistant weed species, such as Ambrosia or Amaranthus

species. See Section III.A.1 for additional information supporting the anticipated use pattern.

4 Option 2 would be used for less aggressive glyphosate resistant weed species, such as marestail. See Section 

III.A.1 for additional information supporting the anticipated use pattern.

5 Monsanto and academics recommend the use of soil residuals as part of a comprehensive weed resistance 

management program to ensure that two effective herbicide modes-of-action are used in soybean and to provide 

protections against additional resistance development to existing herbicides used on soybeans.
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The potential increase in dicamba use in U.S. soybean production upon deregulation of DT 

soybean was assessed by estimating the total dicamba use across soybean acres. Assuming 

100% adoption of DT soybean across all U.S. soybean acreage75 and an application of dicamba 

at the maximum labeled use rate on all soybean acres, dicamba use on DT soybean could 

potentially total 150 million pounds. Assuming the anticipated use rate of 0.5 lb a.e. per acre 

dicamba for preemergence applications and 0.38 lb a.e. per acre dicamba for postemergence 

applications, and using a conservative assumption that DT soybean has 100% adoption across 

all U.S. geographies and conservation tillage systems are used on approximately 40% of the U.S. 

soybean acres (CTIC, 2007), dicamba use on DT soybean would total approximately 44 million 

pounds (See Table A-5). 

In practice, however, a single early season in-crop application per year of dicamba at 0.38 lb a.e. 

per acre is expected on the majority of DT soybean planted acres. However, in no-till or 

conservation tillage soybean systems, an additional preplant application at 0.50 lb a.e. per acre 

could also be common practice, and in areas where more aggressive glyphosate resistant weeds, 

such as Ambrosia and Amaranthus species, are present two in-crop applications at 0.5 lb a.e. each 

may be needed in some situations. These anticipated use patterns represent a high-end estimate 

for predicting dicamba use associated with DT soybean integrated with the glyphosate-tolerant 

soybean system. Thus, when considering a more realistic adoption rate for DT soybean of 

40%, dicamba use on DT soybean would total approximately 20.5 million pounds (See Table 

A-5). 

It is anticipated that dicamba applications will continue for currently labeled crops at the 

dicamba-treated acreage levels and amounts presented in Table A-1, such that the dicamba 

treatment to DT soybean will thereby result in a total U.S. dicamba use of approximately 24.3 

million pounds annually. This level of dicamba use would be approximately double the 

historical peak level experienced since dicamba’s introduction in 1967. 

Taking into consideration the above assessment, the potential dicamba-treated DT soybean 

acreage is estimated to be 40% of the U.S. soybean acres, and would represent approximately 

30 million dicamba-treated soybean acres. Considering the acreage currently treated with 

dicamba (25.3 million acres of which 0.87 million acres are soybean in 2011; see Table A-1 and 

A-2), this would potentially result in a total of 55.3 million acres treated with dicamba. As 

presented previously, dicamba was used on approximately 36 million acres at its peak use in 

1994.

 

75 Based on approximately 75 million acres planted to soybean in 2011 (USDA-NASS, 2013).
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Table A-5. Projected Dicamba Use on DT Soybean 

Dicamba 

Treated 

DT 

soybean 

Acres 

Use Scenario (000,000)

# PRE 

applications

PRE 

application 

rate 

(lb/acre 

a.e.)

# POST 

applications 

(V3 or V3 & 

R1)

POST 

application 

rate 

(lb/acre 

a.e.)

Total lbs 

of Dicamba

(000,000)a

Total 

Annual lbs 

of Dicamba 

Maximum labeled use pattern, 100% adoption

75 1 1.0 2 0.50 150 150

Anticipated use pattern, 100% adoption

no-till acres b 30 1 0.5 1 0.38 26.4

conventional tillage acresc 45 1 0.38 17.1

44

Anticipated use pattern, anticipated peak adoption of dicamba-treated DT soybean acres

no-till acres b 12d 1 0.5 1 0.38 10.6

conventional tillage acresc 18d 1 0.38 6.8

Resistant Amaranthus spp. Acres e 5 2 0.31f 3.1

20.5g

a Total lbs dicamba is calculated combining the lbs of dicamba PRE and POST, where the lbs dicamba used either PRE or POST is calculated by multiplying the number of applications 

by the application rate for the respective application timing. 

b No-tillage is practiced on 40% of the U.S. soybean acres (CTIC, 2007).

c Conventional tillage acres also includes acres where reduced or minimum tillage is practiced and where it is assumed that a preemergent application of dicamba will be needed for weed 

control.

d Monsanto projects dicamba to be used on 40% of U.S. soybean acres (i.e., 30 million acres).

e These acres are a subset of the no-till and conventional tillage acres.

f Monsanto anticipates that two POST applications at 0.5 lb/acre a.e. each will be needed on acres resistant with Amaranthus spp. Since these acres are a subset of the no-till and 

conventional tillage acres where a single POST application at 0.38 lb/acre dicamba a.e. has already been accounted for, the POST application rate is adjusted to avoid double counting 

of dicamba use on this subset of acres (i.e., adjusted POST application rate = 0.5 lb/acre – (0.38÷2) lb/acre).

g This figure is slightly less than the estimate of 22 million pounds described in Section VIII.H of the petition because it subtracts out the single 0.38 lb/acre a.e. application already 

accounted for in the no-till and conventional tillage calculations.
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A.3.3. Benefits of DT Soybean for Weed Management 

Upon integration of DT soybean into the glyphosate-tolerant soybean system, dicamba will 

provide excellent control of numerous annual and perennial broadleaf weed species, including 

populations of broadleaf weeds that are resistant to ALS, atrazine, or glyphosate herbicides. 

Table A-6 shows weed control ratings for dicamba, glyphosate and several glyphosate tank 

mixtures when applied as a preplant burndown application to common broadleaf weed species 

found in soybean fields of the Midwest and Southeast regions. An application of dicamba 

alone provides effective control of a broad spectrum of winter and summer annual and 

perennial broadleaf weed species. In comparison, glyphosate alone provides excellent control 

of many grass species in addition to many of the annual and perennial broadleaf species listed. 

However, dicamba provides a higher level of control of certain broadleaf weeds including 

common lambsquarters, Pennsylvania smartweed, red clover, alfalfa, marestail, hairy vetch, and 

prickly lettuce. Dicamba will be very complementary in mixtures with glyphosate for weed 

control in a preplant application (Johnson et al, 2010) and will offer growers equal or superior 

weed control to other glyphosate mixtures because it offers reduced potential herbicide 

antagonism, improved efficacy and broader weed spectrum. See Appendix B, Section B.2.5 for 

detailed benefit analysis of DT soybean.

The dicamba tolerance trait in DT soybean will permit in-crop applications of dicamba to 

soybean with excellent crop safety (crop tolerance). Dicamba will also complement the weed 

control of in-crop applications of glyphosate when applied as a mixture or in sequence. Table 

A-7 shows common broadleaf weed responses to dicamba compared to glyphosate and several 

glyphosate labeled tank mixtures in soybean. Since dicamba is not currently labeled for in-crop 

applications in soybean, weed control ratings for dicamba were taken from labeled in-crop 

applications of dicamba in corn for comparison purposes. Glyphosate will continue to provide 

broad spectrum control of annual grasses and broadleaf weeds, while dicamba will provide 

improved control of common ragweed, giant ragweed, hemp sesbania, morningglory species, 

and prickly sida. As presented in Table A-6, dicamba is more effective in controlling marestail 

then glyphosate. Likewise, in comparison to glyphosate, dicamba is expected to also improve 

the control of lambsquarters, eastern black nightshade, kochia, palmer pigweed, and wild 

buckwheat. In addition to complementing the weed control of glyphosate, dicamba will 

provide another mode of action in the Roundup Ready soybean system to lower the potential 

risk of weeds developing resistance to glyphosate (see discussion later in this appendix). 

Furthermore, dicamba will provide an alternative mode of action for control of broadleaf weeds 

with populations known to be resistant to ALS and PPO classes of herbicides (see Table A-8 

for herbicide listings).

Application of both dicamba and glyphosate to DT soybean combined with the glyphosate 

tolerant soybean system will provide effective control of both dicamba- and glyphosateresistant broadleaf weeds (Johnson et al, 2010). In the U.S., kochia (Kochia scoparia) and prickly 

lettuce (Lactula serriola) are the only species with biotypes confirmed to be resistant to dicamba 

after 40+ years of use (Heap, 2009). Additionally, a population of lambsquarters (Chenopodium 

album) has been confirmed as resistant in New Zealand, and in Canada common hempnettle 

(Galeopsis tetrahit) and wild mustard (Sinapis arvensis) have been confirmed as resistant, for a total 

of five species worldwide with confirmed resistance to dicamba. Glyphosate has been shown 

to provide good to excellent control of all five of these broadleaf weeds. In addition, there are 

3 species (spreading dayflower (Commelina diffusa), field bindweed (Convolvulus arvensis) and wild 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 371 of 946

carrot (Daucus carota)) in the U.S. with confirmed resistance to 2,4-D. Of the dicamba and 

2,4-D species with known resistance in the U.S. and Canada, cross resistance between dicamba 

and 2,4-D has only been documented in wild mustard. However, cross resistance within the 

other species can not be totally ruled out nor assumed to be present. Currently in the U.S., six 

grass species and seven broadleaf species have been confirmed to have resistance to glyphosate. 

Dicamba provides good to excellent control of all seven of these broadleaf species. None of 

these broadleaf weed biotypes have been shown to have populations that are resistant to both 

glyphosate and dicamba. However, there are known resistant populations of kochia that are 

either resistant to glyphosate or to dicamba, but no population with known resistance to both 

glyphosate and dicamba. Since there is no cross resistance between dicamba and glyphosate 

either product can be effective on kochia populations resistant to the other. A more detailed 

discussion regarding the potential development of dicamba resistance in weeds can be found in 

Appendix B of the Environmental Report.

 
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Table A-6. Common Broadleaf Weed Responses to Preplant Burndown Herbicides

Common Broadleaf Weeds1,2

Herbicide/Application LQ CR GR SW CC

M, 

SP CT RC AL HV MT PL

DN

, 

HB DL CG

Spring Preplant Application

2,4-D (0.5 lb/1.0 lb) - - - - - 9 -/6 6/8 -/7 6/8 8/9 8/9 -/8 6/7 9/9

Dicamba 9 9 9 9 6 7 - 9 8 8 7 9 - 7 -

Dicamba + 2,4-D 9 9 9 9 6 9 6 9 8 9 9 9 - 8 9

Glyphosate 8 9 8 7 7 8 6 7 6 6 6 8 - 7 7

Glyphosate + 2,4-D 9 9 9 8 7 9 6 8 8 8 8+ 9 6 8 9

Glyphosate + Canopy 8 9 9 9 7 8 6 7 6 6 8 8+ 9 8+ 9

Glyphosate + Canopy + 2,4-D 9 9 9 9 7 9 6 8 8 8 9 9 9 8+ 9

Glyphosate + Gangster + 2,4-D 9 9 9 9 7 9 6 8 8 8 9 9 8 8 9

Glyphosate + Python + 2,4-D 9 9 9 8 7 9 6 8 8 8 9 9 6 8 9

Glyphosate + Scepter + 2,4-D 9 9 9 8 7 9 6 8 8 8 8+ 9 6 8 9

Gly + Sonic/Authority First + 

2,4-D 9 9 9 9 7 9 6 8 8 8 9 9 8 8 9

Glyphosate + Valor + 2,4-D 9 9 9 8 7 9 6 8 8 8 8+ 9 8 7 9

1All weed control ratings are from the 2009 Weed Control Guide for Ohio and Indiana – Weed Responses to Burndown Herbicides, Ohio 

State University and Purdue University (Loux et al., 2009). Weed control ratings for weeds are: 9 = 90% to 100%, 8 = 80% to 90%, 7 = 

70% to 80%, 6 = 60% to 70%, and - = less than 60% control, not recommended. Ratings assume the herbicides are applied in the manner 

suggested in the guidelines and according to the label under optimum growing conditions.

2Weed species: LQ = lambsquarters, CR = common ragweed, GR = giant ragweed, SW = annual smartweed, CC = common chickweed, 

M & SP = mustard and shephard’s purse, CT = Canada thistle, RC = red clover, AL = alfalfa, HV = hairy vetch, MT = marestail, PL = 

prickly sida, DN & HB = deadnettle & henbit, DL = dandelion, and CG = crested groundsel
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Table A-7. Common Broadleaf Weed Responses to Dicamba Compared to Labeled Postemergence Herbicides in Soybean 

Production

Common Broadleaf Weeds1,2

Herbicide/Application BN CB CR GR HS LQ MG PA PW PS SP SW VL WH

Postemergence

Bentazon - 9 7 6 4 7 2-9 4 - 8 0 9 8+ -

Chlorimuron - 9 8 7+ 8 - 8-9 6 9 2 7 8 8 -

Cloransulam - 9 9 9 3 - 8-9 2 - 2 7 8 9 -

Chlorimuron/thifensulfuron - 9 8 7+ NA 8 NA NA 9 NA NA 9 9 -

Dicamba38 9 9 9 9 8 9 9 8 8 8 8 7+ 8

Flumiclorac - 7 7 - NA 7 NA NA 7 NA NA - 9 7

Fomesafen 8 7 8+ 8 9 - 8-9 8 9 2 3 7 6 9

Glyphosate 8 9 8+ 8 7 8 7-9 9 9 7 8 8 8 8

Glyphosate/imazethapyr 9 9 8+ 8+ NA 8+ NA NA 9 NA NA 9 9 8

Imazamox 9 8 7 8 NA 8 NA NA 9 NA NA 8 9 -

Imazethapyr 9 9 6 7 0 6 7-9 6 9 6 0 9 9 -

Lactofen 8+ 8 9 8 9 - 8-9 8 9 8 5 6 7 9

Thifensulfuron - 6 - - NA 8 NA NA 9 NA NA 8 9 -

1All weed control ratings except for HS, MG, PA, PS, and SP are from the 2009 Weed Control Guide for Ohio and Indiana – Ohio State 

University and Purdue University (Loux et al., 2009). Ratings for HS, MG, PA, PS, and SP are from the 2009 Weed Control Guidelines for 

Mississippi, Mississippi State University (MSU, 2010), except for dicamba ratings for PA are from the 2010 Weed Control Manual for 

Tennessee (University of Tennessee, 2010). Weed control ratings for weeds, except HS, MG, PA, PS, and SP, are: 9 = 90% to 100%, 8 = 

80% to 90%, 7 = 70% to 80%, 6 = 60% to 70%, and - = less than 60% control, not recommended. Weed control ratings for HS, MG, 

PA, PS, and SP are: 9-10 = excellent, 7-8 = good, 4-6 = fair, 0-3 = none to slight. Ratings assume the herbicides are applied in the manner 

suggested in the guidelines and according to the label under optimum growing conditions. NA denotes not available.

2Weed species: BN = black nightshade, CB = cocklebur, CR = common ragweed, GR = giant ragweed, LQ = lambsquarters, MG = 

morningglory spp., HS = hemp sesbania, PA = palmer and spiny pigweed, PW = pigweed, PS= prickly sida, SP = sicklepod, SW = 

smartweed, VL = velvetleaf, and WH = waterhemp 

3Weed control ratings for dicamba are from postemergence applications in corn.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 374 of 946

Table A-8. Herbicide Use in Soybean Use in the U.S. in 20121

Herbicide Chemical Family

Mode-of-Action 

(MOA)

PercentTreated Acres

Total Area 

Applied

(Percent/MOA)

Quantity 

Applied

(1000 lbs)

Total Quantity 

Applied

(1000 lbs/MOA)

Glyphosate glycine EPSPS inhibitor 98 100 109,336 110,589 Sulfosate glycine 3 1,253

Pendimethalin dinitroanaline Tubulin inhibitor 2

4

1,559 2,865 Trifluralin dinitroanaline 2 1,306

Metribuzin triazinone PSII inhibitor 3 11 675 1,753 Sulfentrazone triazolinone 8 1,078

Chlorimuron-ethyl sulfonylurea

ALS inhibitor

11

26

187

590

Cloransulam-methyl triazolopyrimidine 4 83

Flumetsulam triazolopyrimidine * 14

Imazamox imidazolinone * 6

Imazaquin imidazolinone * 34

Imazethapyr imidazolinone 5 221

Rimsulfuron Imidazolinone * 4

Thifensulfuron sulfonylurea 5 31

Tribenuron-methyl sulfonylurea 1 10

Acetochlor chloroacetamide Cell division

inhibitor

1

9

635

Metolachlor chloroacetamide 7 5,683 6,553

Dimethenamid chloroacetamide 1 235

Paraquat bipyridilium PSI disruption 3 3 813 813
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 375 of 946

Table A-8 (continued). Herbicide Use in Soybean Use in the U.S. in 20121

Herbicide Chemical Family

Mode-of-Action 

(MOA)

PercentTreated Acres

Total Area 

Applied

(Percent/MOA)

Quantity 

Applied

(1000 lbs)

Total Quantity 

Applied

(1000 lbs/MOA)

Clethodim cyclohexenone

ACCase inhibitor

9

14

524

907

Fenoxaprop aryloxyphenoxy 

propionate * 7

Fluazifop-P-butyl aryloxyphenoxy 

propionate 3 195

Quizalofop-P-ethyl aryloxyphenoxy 

propionate 2 118

Sethoxydim cyclohexenone * 63

Acifluorfen diphenylether

PPO inhibitor

1

29

210

2,477

Carfentrazone-ethyl triazolinones * 1

Fluthiacet thiadiazole 2 10

Flumiclorac-pentyl N-phenylphthalimide 1 35

Flumioxazin N-phenylphthalimide 11 602

Fomesafen diphenylether 8 1,347

Lactofen diphenylether 2 192

Saflufenacil pyrimidinedione 4 80

2,4-D phenoxy

Synthetic auxin

15

15

6,021

6,108 Dicamba benzoic acid * 87

Total 132,979

* Area receiving application is less than 0.5 percent.

1 Data derived from USDA-NASS (2013b). Planted acreage for the nineteen primary soybean production states was 72.9 million acres, which 

represented 96.5% of total planted acres
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 376 of 946

A.3.4. Herbicide Use Trends: Impact of DT Soybean on future herbicide use

The objective of this analysis is to provide information regarding: (1) the current and expected 

growth in use of non-glyphosate herbicides in glyphosate-tolerant soybean and cotton in the absence 

of DT soybean and DGT cotton; (2) the herbicides most likely to be replaced by dicamba, and the 

extent of this potential replacement when DT soybean and DGT cotton systems are 

commercialized; (3) the projected change in overall herbicide use when DT soybean and DGT 

cotton are commercialized; and (4) a comparative analysis of dicamba and alternative soybean and 

cotton herbicides, including an emphasis on herbicide risk profiles and comparative herbicide 

efficacy.

A.3.4.1. Materials and Methods

This analysis utilizes unpublished grower survey data obtained from an independent, private-market 

research company that provides farm-survey information on agricultural herbicide usage in the U.S. 

This information reflects the most current data available on U.S. herbicide usage, and presents data 

on glyphosate-tolerant soybean from 2002 through 2011 to represent herbicide use after widespread 

adoption of glyphosate-tolerant soybean and after glyphosate-resistant weeds had begun impacting 

weed control decisions in soybean cultivation. The majority of data are presented in terms of total 

acres treated (TAT), which is the number of acres treated with an herbicide. The use of TAT 

provides a way to look at herbicide use that is independent of the various use rates of herbicides. If 

an herbicide is used more than once on an acre, the TAT will reflect this multiple use, and 

consequently the TAT may exceed the number of crop acres planted. This method provides a more 

complete view of herbicide use. 

This analysis organizes data in two broad usage sets (Table A-9): preplant/pre-emergence to the 

crop (PRE) and post-emergence in-crop use (POST). The PRE set are herbicides applied prior to 

planting the crop through planting of the crop, but before crop emergence regardless of their modeof-activity. The POST set are herbicides applied after crop emergence regardless of their mode-ofactivity. In glyphosate-tolerant soybean, a total of 53 different non-glyphosate herbicides had been 

used in the PRE timing, while 37 different non-glyphosate herbicides had been used in the POST 

timing (Table A-9). The total PRE and POST herbicides used in glyphosate-tolerant soybean acres 

from 2002 through 2011 are presented in Table A-10 and Table A-11 below, respectively. 

To better understand how dicamba would impact overall herbicide use at peak penetration of 

dicamba-tolerant soybeans, projections of the growth of TAT for all herbicides including glyphosate 

after 2011 were developed using a four-parameter logistic regression model. The four-parameter 

logistic model is one of the most commonly used growth rate models because it has properties 

desirable for this analysis (i.e., monotonically increasing, symmetric about an inflection point, and 

upper/lower asymptotes). For this analysis, a major consideration is the ability to estimate the 

limiting maximum value of TAT, which is mathematically referred to as an upper asymptote. This 

means that the model estimates a potential maximum value of TAT which will not be exceeded at 

any point in time. Based on expected grower practices, which are based upon weed management 

needs and the acceptable level of management generally applied to soybean weed-control practices, 

including herbicide and mechanical tillage costs, it was assumed that a grower would be expected to 

make, on average, 1.5 applications of PRE herbicides and 2 applications of POST herbicides in 

glyphosate-tolerant soybeans by 2015. Specifically, the 1.5 PRE timing applications were estimated 

based on: (1) approximately 50% of soybean acres utilizing conservation tillage and receiving at least 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 377 of 946

1 preplant burndown herbicide application (e.g., glyphosate); and (2) all glyphosate-tolerant soybean 

acres receiving at least 1 herbicide application (soil residual or postemergence active) after planting 

but before crop emergence. Thus, 1.5 PRE herbicide applications are expected to be made on 

average across all glyphosate-tolerant soybean acres. Similarly, the estimate of 2 POST herbicide 

applications in glyphosate-tolerant soybeans was based on the expectation that, on average, 

glyphosate would be supplemented by either a postemergence grass or a postemergence broadleaf 

herbicide. These are projections for the average number of herbicide applications, for that reason, in 

some cases where aggressive glyphosate resistant weeds, such as Amaranthus spp., may be present 

an additional postemergence application of a non-glyphosate herbicide may be needed. Conversely, 

the non-glyphosate postemergence grass or broadleaf herbicide may not be needed in some cases 

based on the specific weed spectrum in the soybean field.

Growth modeling was conducted using existing TAT data for all herbicides in glyphosate-tolerant 

soybeans from 2002 through 2011 (Table A-10 and Table A-11) with an upper asymptote set at 109 

million acres for the PRE timing (Figure A-1) and 145 million acres for the POST timing (Figure A2). These asymptotes were estimated by multiplying the estimated maximum number of herbicide 

applications for each application timing (i.e., PRE or POST) by the anticipated number of 

glyphosate-tolerant soybean acres. The number of glyphosate-tolerant soybean acres planted after 

2011 was assumed to remain constant at 72.5 million acres, which was based on the average of 2008 

through 2011 planted glyphosate-tolerant soybean acres. To derive estimates from the model, an 

assumption was made that the total number of treated acres would reach 99% of its limiting 

maximum value (or upper asymptote) by 2015 because herbicide use is expected to plateau in 2015 

based on an aggressive adoption rate for diversified weed management practices. The projected 

TAT for the PRE and POST herbicides sets through 2020 are presented in Table A-10 and 

Table A-11, respectively. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 378 of 946

Table A-9. Non-Glyphosate Herbicides Used in Glyphosate-Tolerant Soybeans from 2002 to 2011a

Preemergence (PRE) Active Ingredients Postemergence (POST) Active Ingredients 

2,4-D

2,4-DB

Acifluorfen

Alachlor

Bentazone

Carfentrazone-ethyl

Chlorimuron 

Chlorsulfuron 

Clethodim

Clomazone

Cloransulam-methyl 

Dicamba

Diflufenzopyr 

Dimethenamid 

Dimethenamid-P

Ethalfluralin

Fenoxaprop

Fluazifop

Flufenacet

Flumetsulam

Flumiclorac 

Flumioxazin

Fluthiacet-methyl

Fomesafen

Glufosinate

Imazamox

Imazaquin

Imazethapyr

Iodosulfuron

Lactofen

Linuron

MCPA

Metolachlor

Metolachlor-S

Metribuzin

Metsulfuron

MSMA

Nicosulfuron

Norflurazon 

Paraquat

Pelargonic acid

Pendimethalin

Pyraflufen ethyl 

Quizalofop

Rimsulfuron 

Saflufenacil 

Sethoxydim

Simazine

Sulfentrazone 

Sulfosate

Thifensulfuron 

Tribenuron methyl 

Trifluralin

2,4-D

2,4-DB

Acetochlor

Acifluorfen

Alachlor

Bentazone

Carfentrazone-ethyl

Chlorimuron 

Clethodim

Cloransulam-methyl 

Dicamba

Dimethenamid 

Dimethenamid-P

Fenoxaprop

Fluazifop

Flumetsulam

Flumiclorac 

Flumioxazin

Fluthiacet-methyl

Fomesafen

Imazamox

Imazaquin

Imazethapyr

Lactofen

Linuron

Metolachlor

Metolachlor-S

Naptalam

Paraquat

Pelargonic acid

Pendimethalin

Pyraflufen ethyl 

Quizalofop

Sethoxydim

Sulfosate

Thifensulfuron 

Tribenuron methyl

a Unpublished market research data (Monsanto, 2011)
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 379 of 946

Table A-10. Total Acres Treated (TAT) for PRE Applications – Soybean

Total Acres Treated

Market Research Dataa

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

TAT nonglyphosate 

herbicides

13,193,707 14,840,690 14,668,394 13,212,012 15,174,490 14,638,461 22,202,786 26,395,565 29,864,690 40,536,350

% increase 2002-

2007 

11%

% increase 2007-

2011

177%

TAT for 

glyphosate only

15,717,762 14,961,613 15,786,481 18,506,336 20,714,073 21,483,177 29,008,410 28,038,773 25,344,134 24,895,051 

Total TAT (nonglyphosate + 

glyphosate 

herbicides)

 

28,911,469 

 

29,802,303 

 

30,454,875 

 

31,718,348 

 

35,888,563 

 

36,121,638 

 

51,211,196 

 

54,434,338 

 

55,208,824 

 

65,431,401 

Planted GT 

Soybean acres

60,349,592 64,979,824 67,387,514 66,589,441 70,243,541 61,116,671 71,592,623 73,219,834 74,059,185 71,734,537
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 380 of 946

Table A-10 (continued). Total Acres Treated (TAT) for PRE Applications – Soybean 

Total Acres Treated

Projected TAT Using Logistic Modeling to Estimate Growth

2012 2013 2014 2015 2016 2017 2018 2019 2020

TAT nonglyphosate 

herbicides

 

64,773,279 

 

74,715,994 

 

79,267,452 

 

81,087,544 

 

81,775,565 

 

82,030,078 

 

82,123,472 

 

82,157,642 

 

82,170,130 

% increase 2011-

2015 100%

TAT for 

glyphosate only

26,800,000 26,800,000 26,800,000 26,800,000 26,800,000 26,800,000 26,800,000 26,800,000 26,800,000 

Total TAT (nonglyphosate + 

glyphosate 

herbicides) 91,573,279 101,515,994 106,067,452 107,887,544 108,575,565 108,830,078 108,923,472 108,957,642 108,970,130

Planted GT 

Soybean acresb

72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 

a Unpublished market research data (Monsanto, 2011)

b Estimated
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 381 of 946

Table A-11: Total Acres Treated (TAT) for POST applications – Soybean 

Total Acres Treated

Market Research Dataa

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

TAT nonglyphosate 

herbicides

5,989,024 6,763,229 5,954,804 4,954,480 5,568,882 5,595,885 9,471,130 16,016,729 20,726,606 24,928,111

% increase 

2002-2007 

-7%

% increase 

2007-2011

345%

TAT for 

glyphosate 

only

69,983,206 78,770,855 81,581,659 78,442,879 73,746,629 69,000,104 85,111,702 86,217,950 92,455,945 86,782,777 

Total TAT 

(nonglyphosate 

+ 

glyphosate 

herbicides)

75,972,230 85,534,084 87,536,463 83,397,359 79,315,511 74,595,989 94,582,832 102,234,679 113,182,551 111,710,888 

Planted GT 

Soybean 

acres

60,349,592 64,979,824 67,387,514 66,589,441 70,243,541 61,116,671 71,592,623 73,219,834 74,059,185 71,734,537
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 382 of 946

Table A-11 (continued). Total Acres Treated (TAT) for POST Applications – Soybean 

Total Acres Treated

Projected TAT Using Logistic Modeling to Estimate Growth

2012 2013 2014 2015 2016 2017 2018 2019 2020

TAT nonglyphosate 

herbicides

46,043,835 52,619,725 56,137,061 57,850,059 58,646,207 59,008,178 59,171,102 59,244,102 59,276,743

% increase 

2007-2015

132%

TAT for 

glyphosate 

only

86,000,000 86,000,000 86,000,000 86,000,000 86,000,000 86,000,000 86,000,000 86,000,000 86,000,000 

Total TAT 

(nonglyphosate + 

glyphosate 

herbicides)

132,043,835 138,619,725 142,137,061 143,850,059 144,646,207 145,008,178 145,171,102 145,244,102 145,276,743

Planted GT 

Soybean 

acresb

72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000 72,500,000

a Unpublished market research data (Monsanto, 2011)

b Estimated
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 383 of 946

Figure A-1. Regression model and predictions for PRE non-glyphosate soybean herbicides

The shaded area represents the 95% confidence interval for the modeled projection.

Figure A-2. Regression model and predictions for POST non-glyphosate soybean herbicides

The shaded area represents the 95% confidence interval for the modeled projections.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 384 of 946

A.3.4.2. Analysis of PRE Soybean Herbicide Use from 2002-2011 

The use of non-glyphosate herbicides included in the PRE set is influenced by use of conservation 

tillage (i.e., reliance on herbicides to control emerged weeds prior to crop planting) and use of 

residual herbicides applied preplant and/or preemergent to crop emergence. The use of nonglyphosate PRE herbicides in glyphosate-tolerant soybeans was relatively flat from 2002 through 

2007, with only an 11% increase in TAT between 2002 and 2007 (Table A-10). In 2007, glyphosatetolerant soybeans were grown on 61 million acres. At that time, the primary non-glyphosate 

herbicides used were those providing postemergence control of broadleaf weeds. From 2008 to 

2011, there was a 177% increase in the use of non-glyphosate herbicides in the glyphosate-tolerant 

soybean PRE segment. In 2011, glyphosate-tolerant soybeans were grown on 72 million acres, an 

18% increase from 2007. It can be concluded from this data that the growth in non-glyphosate 

herbicide use was not driven just by an increase in the total planted acres of glyphosate-tolerant 

soybean. Instead, this increase in use of non-glyphosate herbicides in the 2008 through 2011 time 

period is consistent with the increased emphasis by the public and private sectors on promoting 

more diversified weed management and also the increase in glyphosate resistant weeds during this 

time period. Likewise, it can be concluded that non-glyphosate herbicide use will continue to 

increase and eventually plateau, regardless of the expected launch of dicamba-tolerant crops. 

Assuming no commercialization of dicamba-tolerant soybeans, the growth in PRE non-glyphosate 

TAT could be expected to increase to approximately 81 million acres by 2015, which is a further 

100% increase in non-glyphosate herbicide use from 2011 (Table A-10). Of the planted glyphosatetolerant soybean acres in 2011, approximately 43% received a non-glyphosate PRE herbicide 

application (Table A-12). The number of glyphosate applications in glyphosate-tolerant soybeans 

has been relatively flat since 2007 and is expected to remain flat in the foreseeable future regardless 

of the commercialization of dicamba-tolerant soybean (Table A-12).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 385 of 946

Table A-12. Base acres and average number of applications for PRE segment – Soybeana

Acres a

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Averages 

(2008-2011)

Non-glyphosate herbicides

Base acresb

19,516,983 17,903,463 16,760,037 15,406,031 15,420,411 14,290,515 19,622,747 23,552,933 26,610,180 31,144,934

Base acres as percent of 

GT planted acres 32% 28% 25% 23% 22% 23% 27% 32% 36% 43%

Avg # of nonglyphosate applications 

per treated acrec 1.19 1.24 1.24 1.20 1.19 1.17 1.23 1.25 1.26 1.39

Glyphosate herbicides

Base Acresb

14,967,089 14,123,133 15,013,484 17,446,790 19,509,232 19,800,590 25,978,778 25,660,098 24,190,709 23,414,531

Base acres as percent of 

GT planted acres 25% 22% 22% 26% 28% 32% 36% 35% 33% 33%

Avg # of glyphosate 

applications per treated 

acrec 1.05 1.06 1.05 1.06 1.06 1.08 1.12 1.09 1.05 1.06

Planted soybean acres

GT Soybean planted 

acres 60,349,592 64,979,824 67,387,514 66,589,441 70,243,541 61,116,671 71,592,623 73,219,834 74,059,185 71,734,537 72,651,545

Total soybeans planted 

acres 73,043,055 73,652,916 74,809,004 72,969,983 74,810,075 63,975,002 74,404,952 77,584,979 78,725,010 74,835,004 76,387,486

a Unpublished market research data (Monsanto, 2011).

b The base acre is the number of acres that receives at least 1 application of a herbicide.

c The reported average number of applications as tabulated in the market research data base does not allow values for individual segments (glyphosate and non-glyphosate 

herbicides) to be combined to generate a number representative of the total number of average applications in the segment (PRE or POST).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 386 of 946

A.3.4.3. Analysis of POST Soybean Herbicide Use from 2002-2011

The use of herbicides at this timing is primarily influenced by the need to control weeds after they 

emerge in the crop or to extend the preemergence residual control of weeds longer into the growing 

season. As in the case of non-glyphosate PRE herbicides, the use of non-glyphosate POST 

herbicides applied in glyphosate-tolerant soybeans was flat from 2002 through 2007, with essentially 

no growth in TAT between 2002 and 2007 (Table A-11). However, from 2008 to 2011 there was a 

345% increase in TAT for the use of non-glyphosate POST herbicides in the glyphosate-tolerant 

soybean. During the same time period, glyphosate-tolerant soybean acres grew approximately 18%. 

As in the case for the PRE herbicides, this data indicates that the increase in non-glyphosate 

herbicide use was not solely related to an increase in planted glyphosate-tolerant soybean acres. The 

increased use of non-glyphosate POST herbicides after 2008 is evidence of increased adoption of 

diversified weed management practices by farmers. These outcomes are consistent with farmer 

adoption of recommendations from the public and private sectors on how best to proactively and 

reactively manage resistance. Likewise, it can be concluded that non-glyphosate herbicide use will 

continue to increase and eventually plateau, regardless of the expected launch of dicamba-tolerant 

soybean. Assuming no commercialization of dicamba-tolerant soybean, the growth in TAT from 

non-glyphosate POST herbicides could be expected to increase to approximately 58 million acres by 

2015, which is a 132% increase in non-glyphosate herbicide use from 2011 (Table A-11). In 2011 

approximately 30% of glyphosate tolerant soybean acres received a non-glyphosate POST herbicide 

application (Table A-13). The number of glyphosate applications in glyphosate-tolerant soybean in 

the POST segment has been relatively flat since 2002 and is expected to remain at a stable rate in the 

future regardless of whether or not DT soybean is commercialized (Table A-13).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 387 of 946

Table A-13. Base acres and average number of applications for POST segment – Soybeana

Acres a

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Averages 

(2008-2011)

Non-glyphosate herbicides

Base acresb 5,112,506 5,825,154 5,428,650 4,491,573 4,996,258 4,921,061 8,485,432 14,085,236 17,177,978 21,455,105

Base acres as percent of 

GT planted acres 8% 9% 8% 7% 7% 8% 12% 19% 23% 30%

Avg # of non-glyphosate 

applications per treated 

acrec

1.17 1.16 1.10 1.10 1.11 1.14 1.12 1.14 1.21 1.16

Glyphosate herbicides

Base Acresb 58,357,957 62,808,659 65,942,923 63,966,600 65,823,639 59,949,798 69,491,079 71,727,511 71,962,333 68,739,858

Base acres as percent of 

GT planted acres 97% 97% 98% 96% 94% 98% 97% 98% 97% 96%

Avg # of glyphosate 

applications per treated 

acrec

1.20 1.25 1.24 1.23 1.12 1.15 1.22 1.20 1.28 1.26

Planted soybean acres

GT Soybean planted acres 60,349,592 64,979,824 67,387,514 66,589,441 70,243,541 61,116,671 71,592,623 73,219,834 74,059,185 71,734,537 72,651,545

Total soybeans planted 

acres

73,043,055 73,652,916 74,809,004 72,969,983 74,810,075 63,975,002 74,404,952 77,584,979 78,725,010 74,835,004 76,387,486

a Unpublished market research data (Monsanto, 2011).

b The base acre is the number of acres that receives at least 1 application of a herbicide.

c The reported average number of applications as tabulated in the market research data base does not allow values for individual segments (glyphosate and nonglyphosate herbicides) to be combined to generate a number representative of the total number of average applications in the segment (PRE or POST).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 388 of 946

A.3.4.4. Projected Dicamba Use (TAT and Total Pounds) on DT Soybean

Based upon anticipated use patterns for dicamba on DT soybean as described in Section VIII.H of 

petition #10-188-01p (Monsanto, 2010), projections on the number of dicamba TAT and total 

pounds of dicamba used on DT soybean were determined for the combined PRE and POST 

application timing. The anticipated use projections represent a high-end estimate of the incremental 

dicamba use as described in the petition. Projected dicamba use at peak penetration (assumed to be 

2015 for this analysis) is 47.1 million TAT and 20.5 million pounds (Table A-14). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 389 of 946

Table A-14. Anticipated Total Acres Treated (TAT) for PRE and POST applications of dicamba on DT Soybean

Agronomic Practice

Projected 

acres where 

dicamba 

may be 

useda

Number of 

PRE dicamba 

applicationsb

Average PRE 

application 

rate 

(lb/acre a.e.)b

Number of 

POST 

dicamba 

applicationsb

Average POST 

application rate 

(lb/acre a.e.)b

Projected 2015 

dicamba 

TATc

Projected 2015 

total lbs dicambad

No-Tillage Acres 12,032,000 1 0.5 1 0.38 24,064,000 10,588,160

Conventional Tillage 

Acres 18,048,000 - 1 0.38 18,048,000 6,858,240

Resistant Amaranthus spp.

Soybean Acrese

5,000,000 - 1

f 0.62g 5,000,000 3,100,000

Total high-end projection on dicamba use 47,112,000 20,546,400h

a Soybean is projected to be grown on 75.2 million acres in 2015. Monsanto projects dicamba to be conservatively used on 40% of U.S. soybean acres (i.e., 

30,080,000 acres). No-tillage is practiced on 40% of the U.S. soybean acres (CTIC, 2007). The remaining acres are conventional tillage. 

b See Section VIII.H of the Dicamba-Tolerant Soybean MON 87708 petition #10-188-01p for details regarding the anticipated use pattern for dicamba on 

DT soybean.

c Projected TAT = (Projected Acres x Number of PRE Applications) + (Projected Acres x Number of POST Applications). 

d Projected Total lbs = (Projected Acres x Number of PRE Applications x Avg. PRE rate) + (Projected Acres x Number of POST Applications x Avg. POST rate). 

e These acres are a subset of the no-till and conventional tillage acres

f Monsanto anticipates that two POST applications at 0.5 lb/acre a.e. each will be needed on acres resistant with Amaranthus spp. Since these acres are a 

subset of the no-till and conventional tillage acres where a single POST application has already been accounted for, the number of applications is adjusted 

to avoid double counting on this subset of acres.

g Monsanto anticipates that two POST applications at 0.5 lb/acre a.e. each will be needed on acres resistant with Amaranthus spp. The average application 

rate on these acres is determined by subtracting the 0.38 lb/acre a.e. POST application already accounted for in the no-till and conventional tillage 

calculations (i.e., 0.5 + 0.5 - 0.38 lb/acre).

h This figure is slightly less than the estimate of 22 million pounds described in Section VIII.H of the petition because it subtracts out the single 0.38 lb/acre a.e. 

application already accounted for in the calculation
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A.3.5. Displacement of Other Non-Glyphosate Herbicides by Dicamba Use Following 

Deregulation of DT Soybean 

A.3.5.1. Materials and Methods 

In order to estimate the amount of non-glyphosate herbicides that could be replaced by dicamba, 

Monsanto weed management scientists identified those herbicides most likely to be replaced by 

dicamba from the list of non-glyphosate herbicides currently being used in glyphosate-tolerant 

soybeans (Table A-9). These herbicides were selected based on criteria such as lower efficacy, 

carryover concerns, existing resistance, use restrictions, and/or crop safety. This exercise resulted in 

the selection of 7 and 15 non-glyphosate herbicides in the PRE and POST segments, respectively. 

The herbicides expected to be replaced by dicamba in the PRE set included imazethapyr, 

pendimethalin, metribuzin, trifluralin, 2,4-D, paraquat and glufosinate (Table A-15). The 

herbicides in the POST set included fomesafen, chlorimuron, fluthiacet-methyl, cloransulam-methyl, 

lactofen, flumiclorac, thifensulfuron, imazamox, acifluorfen, bentazone, imazethapyr, imazaquin, 

metolachlor-s, metolachlor and acetochlor (Table A-16). In addition, the percent replacement for 

each herbicide was estimated based upon a technical understanding of the herbicide products and 

the marketplace, and the herbicides were grouped based upon those estimates. The displacement 

analysis presented was conducted relative to the projected use of non-glyphosate herbicides in 2015 

because that was estimated to be the year when non-glyphosate herbicide use would plateau in 

glyphosate-tolerant soybeans based on an aggressive adoption rate for diversified weed resistant 

management practices. Glyphosate use in glyphosate-tolerant soybean has remained relatively 

constant over the last decade and is not projected to increase in the future.

To obtain an accurate estimate of the amount of herbicide that dicamba would potentially displace, 

it was necessary to estimate the number of acres that would be planted to DT soybean and the 

number of DT soybean acres that would be treated with dicamba at peak market penetration. 

Monsanto estimated that DT soybean varieties could be planted on up to 50% of the U.S. soybean 

acres at peak penetration, and that dicamba would be used on up to 80% of those planted acres (i.e., 

40% of U.S. soybean acres). That value represents a high-end estimate of incremental dicamba use 

as described in more detail above. It is reasonable to conclude that the actual market penetration 

and associated dicamba use could likely be lower.

Additional analyses were conducted for each application timing segment to allow for a comparison 

of the projected pounds of herbicide applied in 2015 with and without the commercialization of DT 

soybean. These analyses utilized the same market research as the TAT analysis.
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Table A-15. Projected Total Acres Treated (TAT) for PRE herbicides most likely to be 

displaced by dicamba – Soybean 

Active 

Ingredients

Projected 

% 

Replacem

ent

Primary 

Rationale

2011a2015 (Projected)

TATa TAT 

Replacedb

TATc TAT 

Replacedb

2,4-D, Paraquat, 

glufosinate

60% efficacy, 

carryover, 

and/or 

restricted use

11,441,812 2,746,035 22,883,624 5,492,070 

metribuzin, 

trifluralin

30% crop safety 4,026,148 483,138 8,052,296 966,276 

imazethapyr, 

pendimethalin

10% crop safety, 

carryover, 

and/or 

existing 

resistance

4,476,390 179,056 8,952,780 358,111 

Total Projected 

TAT Replaced

3,408,228 6,816,456 

a Unpublished market research data (Monsanto, 2011). TAT is only for those active ingredients within each 

herbicide grouping.

b TAT replaced = TAT x Projected % Replacement x 40%. Monsanto projects dicamba to be conservatively used on 

40% of U.S. soybean acres at market penetration.

c

2015 TAT is based on the projected growth rate of 100% for non-glyphosate PRE herbicide use taken from 

Table A-10.
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Table A-16. Projected Total Acres Treated (TAT) for POST herbicides most likely to be 

displaced by dicamba – Soybean 

Active 

Ingredients

Projected 

% 

Replacem

ent

Primary 

Rationale

2011 2015 (Projected)

TATa TAT 

Replacedb

TATc TAT 

Replacedb

fomesafen, 

chlorimuron, 

fluthiacet-methyl, 

cloransulammethyl, lactofen 

flumiclorac, 

thifensulfuron, 

imazamox, 

acifluorfen, 

bentazone

80% efficacy, 

carryover, 

crop safety, 

existing 

resistance

15,247,063 4,879,060 35,373,186 11,319,420 

imazethapyr, 

imazaquin

50% efficacy, 

carryover, 

existing 

resistance

2,969,428 593,886 6,889,073 1,377,815 

metolachlor-s, 

metolachlor, 

acetochlor

10% efficacy 4,110,272 164,411 9,535,831 381,433 

Total Projected 

TAT Replaced

 

5,637,357 

 

13,078,667 

a Unpublished market research data (Monsanto, 2011). TAT is only for those active ingredients within each 

herbicide grouping.

b TAT replaced = TAT x Projected % Replacement x 40%. Monsanto projects dicamba to be conservatively used on 

40% of U.S. soybean acres at market penetration.

c

2015 TAT is based on the projected growth rate of 132% for non-glyphosate POST herbicide use taken from 

Table A-11.
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A.3.5.2. Analysis of Displacement of Other Non-Glyphosate Herbicides by Dicamba Use 

Following Deregulation of DT Soybean

The commercialization of a soybean product containing dicamba-tolerance will allow for an increase 

in the use of dicamba for weed control in soybean due to the elimination of in-crop (POST 

segment) and preplant (PRE segment) crop safety concerns. While dicamba is presently labeled for 

preplant uses in soybean, that use is currently limited because the application must be made more 

than 14 days prior to planting in order to address crop safety risks. With crop safety no longer a 

barrier, farmers can incorporate dicamba into their weed management programs because of the 

advantages it offers versus other herbicides. 

Those advantages will translate into dicamba replacing certain non-glyphosate herbicides currently 

used preplant or postemergent in-crop in soybeans. In addition, the ability to use dicamba to 

manage existing resistant weeds will reduce the need for multiple residual herbicides and/or multiple 

postemergence herbicides in some situations. This will drive an overall reduction in herbicide use in 

some situations. For example, Monsanto and academics currently recommend that farmers with 

glyphosate-resistant weeds apply a residual product, such as Valor®(flumioxazin), Gangster®

(flumioxazin/cloransulam) or Authority® First (Cloransulam-methyl/sulfentrazone), preemergence 

to the crop and then follow with glyphosate plus Warrant®(acetochlor) plus either Cobra®(lactofen) 

or Flexstar®(fomesafen). With the ability of farmers to use dicamba in-crop, dicamba would replace 

the need to use acetochlor, lactofen or fomesafen, thus reducing overall herbicide use and 

applications.

Glyphosate is not expected to be replaced by dicamba in either the PRE or the POST segment. 

Dicamba will primarily be used in combination with glyphosate and this combination will simply 

displace glyphosate combinations with other non-glyphosate herbicides and/or glyphosate used 

alone.

A.3.5.2.1. Projected TAT Estimates for Replacement of Currently Used PRE Herbicides by 

Dicamba 

At peak use of DT soybean, dicamba is projected to be used on approximately 40% of total soybean 

acres. The projected 81.1 million TAT for all non-glyphosate PRE herbicides used in soybeans in 

2015 (Table A-10) adjusted for the dicamba use projection of 40% results in a theoretical maximum 

of 32.4 million TAT that could potentially be displaced by dicamba. The non-glyphosate herbicides 

most likely to be displaced by dicamba are listed in Table A-15 and include active ingredients that 

can be used for burndown, residual, or residual and burndown control. These herbicides were 

selected because of the advantages dicamba would offer relative to each selected herbicide and 

expected farmer preferences towards dicamba use (see Table A-15 for specific advantages). A 

projected percent replacement was then estimated for each herbicide based on criteria such as lower 

efficacy, carryover concerns, existing resistance, use restrictions, and/or crop safety. Reductions in 

use of each herbicide were then estimated and herbicides with the same projected percent 

replacement were grouped. In the case of the PRE herbicides, the groupings were 10%, 30%, or 

60%. Applying the projected percent reductions to the projected 2015 TAT for each reduction 

grouping provides an estimate for the number of treated acres that dicamba would replace. Based 

on these assumptions, it can be projected that dicamba would replace an estimated 6.8 million nonglyphosate PRE herbicide TAT in 2015 (Table A-15). Therefore, dicamba could be expected to 

conservatively replace approximately 21% of the projected TAT for all non-glyphosate herbicides 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 394 of 946

used in PRE application timing in 2015 based on the 40% of total planted soybean acres where 

dicamba is projected to be used (i.e., 32.4 million TAT). Note that 2015 is not selected based upon 

the expected year of introduction or peak use of dicamba tolerant soybeans; instead, it was based 

upon current trends and conservative projections on the growth and adoption of non-glyphosate 

herbicide use in glyphosate-tolerant soybeans.

A.3.5.2.2. Projected TAT Estimates for Replacement of Currently Used POST Herbicides by 

Dicamba 

As stated previously, a high-end estimate of dicamba use on soybean is 40% of total soybean acres at 

peak use of DT soybeans. The projected 57.9 million TAT for all non-glyphosate POST herbicides 

used in soybeans in 2015 (Table A-11) adjusted for the dicamba use projection of 40% results in a 

theoretical maximum of 23.1 million TAT that could potentially be displaced by dicamba. The nonglyphosate herbicides most likely to be displaced by dicamba are listed in Table A-16 and include 

active ingredients that can be used for burndown, residual, or residual and burndown control. These 

herbicides were selected because of the advantages dicamba would offer relative to each selected 

herbicide and expected farmer preferences towards dicamba use (see Table A-16 for specific 

advantages). A projected percent replacement was then estimated for each herbicide based on 

criteria such as lower efficacy, carryover concerns, existing resistance, use restrictions, and/or crop 

safety. Reductions in use of each herbicide were then estimated and herbicides with the same 

projected percent replacement were grouped. In the case of the POST herbicides, the groupings 

were 10%, 50%, or 80%. Applying the projected percent reductions to the projected 2015 TAT for 

each herbicide grouping provides an estimate for the number of treated acres that dicamba would 

replace. Based on these assumptions, it can be projected that dicamba would replace an estimated 

13.1 million non-glyphosate herbicide TAT in 2015. Therefore, dicamba could be expected to 

conservatively replace approximately 56% of the projected TAT for all non-glyphosate herbicides 

used in POST application timing in 2015 based upon the above assumption that dicamba will only 

be used on 40% of total planted soybean acres (i.e., 23.1 million TAT). 

A.3.5.2.3. Projected Total Pound Estimates for Replacement of Currently Used Herbicides 

By Dicamba 

The projected total pounds of herbicides in each application segment (PRE and POST) that would 

be replaced by dicamba were determined using the same methodology and data source as the TAT 

analysis described above. The same herbicide growth projections for the PRE and POST 

application segments (i.e., 101% and 132%; see Table A-10 and Table A-11, respectively) were 

applied to the 2011 pounds of herbicide applied data. Based on this analysis, it can be projected that 

dicamba would replace an estimated 3.6 million pounds of PRE non-glyphosate herbicides and 1.6 

million pounds of POST non-glyphosate herbicides in 2015 (Table A-17 and Table A-18, 

respectively). 
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Table A-17. Projected Total Pounds for PRE herbicides most likely to be displaced by 

dicamba – Soybean 

Active Ingredients

Projected 

% 

Replacem

ent

Primary 

Rationale

2011a 2015 (Projected)

Total 

Lbsa

Total Lbs 

Replacedb

Total

Lbsc

Total Lbs. 

Replacedb

2,4-D, Paraquat, 

glufosinate

60% efficacy, 

carryover, 

and/or 

restricted use

6,266,139 1,503,873 12,532,27

8 

3,007,747 

metribuzin, trifluralin 30% crop safety 1,680,767 201,692 3,361,534 403,384 

imazethapyr, 

pendimethalin

10% crop safety, 

carryover, 

and/or existing 

resistance

2,564,019 102,561 5,128,038 205,122 

Total Projected 

Pounds Replaced

1,808,126 3,616,252 

a Unpublished market research data (Monsanto, 2011). Total Lbs is only for those active ingredients within each 

herbicide grouping.

b Total Lbs replaced = Total Lbs x Projected % Replacement x 40%. Monsanto projects dicamba to be 

conservatively used on 40% of U.S. soybean acres at market penetration.

c

2015 Total Lbs is based on the projected growth rate of 100% for non-glyphosate PRE herbicide use taken from 

Table A-10.
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Table A-18. Projected Total Pounds for POST herbicides most likely to be displaced by 

dicamba – Soybean

Active Ingredients

Projected 

% 

Replacem

ent

Primary 

Rationale

2011 2015 (Projected)

Total 

Lbsa

Total 

Lbs 

Replace

d b

Total

Lbsc

Total 

Lbs. 

Replaced

b

fomesafen, chlorimuron, 

fluthiacet-methyl, 

cloransulam-methyl, 

lactofen flumiclorac, 

thifensulfuron, 

imazamox, acifluorfen, 

bentazone

80% efficacy, 

carryover, crop 

safety, existing 

resistance

1,536,012 491,524 3,563,548 1,140,335 

imazethapyr, imazaquin 50% efficacy, 

carryover, 

existing 

resistance

160,245 32,049 371,768 74,354 

metolachlor-s, 

metolachlor, acetochlor

10% efficacy 4,113,250 164,530 9,542,740 381,710 

Total Projected 

Pounds Replaced

688,103 1,596,399 

a Unpublished market research data (Monsanto, 2011). Total Lbs is only for those active ingredients within each 

herbicide grouping.

b Total Lbs replaced = Total Lbs x Projected % Replacement x 40%. Monsanto projects dicamba to be 

conservatively used on 40% of U.S. soybean acres at market penetration.

c

2015 Total Lbs is based on the projected growth rate of 132% for non-glyphosate PRE herbicide use taken from 

Table A-11.
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A.3.6. Net Impact of DT Soybean on Overall Herbicide Use

Table A-19 presents estimates of the net impact of DT soybean on future total acres treated and 

total pounds of active ingredients. At projected peak penetration of dicamba use in DT soybean, an 

increase in both total acres treated and total pounds of herbicide active ingredient applied is 

projected; however, estimated increases are less than 15% of the total herbicide use projections 

(TAT and pounds of active ingredient) if dicamba-tolerant soybean is not commercialized. The 

comprehensive analysis set forth in this appendix was completed to evaluate the assertions made in 

recent publications by Benbrook (2012) and Mortensen et al. (2012), which suggest that the 

commercialization of dicamba-tolerant soybeans and associated use of dicamba will only be additive 

to current herbicide use and, according to Mortensen, could result in a ‘profound’ increase in overall 

herbicide use. The main reasons for their conclusions are that: (1) overall herbicide use in 2007 was 

projected not to change through 2013; and (2) dicamba use would be entirely additive to use of 

existing herbicides. However, this analysis highlights the inaccuracy of these conclusions and clearly 

demonstrates two key conclusions:

(1) The overall use of non-glyphosate herbicides in soybean production has significantly 

grown since 2007, and this growth is expected to continue and eventually plateau. The 

current and projected future growth is due in large part to the adoption of best management 

practices as recommended by public and private sector weed scientists and the development 

and spread of weed resistance. This increase in non-glyphosate herbicide use would occur 

regardless of the commercialization of DT soybeans, and 

(2) When a DT soybean system is available, dicamba would displace a significant amount of 

non-glyphosate herbicides used for weed management. This analysis conservatively projects 

that on acres where DT soybean is planted and dicamba is used, dicamba will replace 

approximately 21% of the projected PRE non-glyphosate herbicide TAT and 56% of the 

projected POST non-glyphosate herbicide TAT. 

The deregulation and subsequent commercialization of DT soybean will not alter the number of 

cultivated soybean acres or the geographical areas where soybean is cultivated in the U.S. 

Consequently, DT soybean will be grown on land that is already highly managed for agricultural 

crop production and where herbicides are widely used today. As described previously, the 

commercialization of DT soybean will result in a slight increase in herbicide use (treated acres and 

pounds of dicamba) on those acres where it is planted and the grower chooses to use dicamba in 

their weed management program. However, the increase in dicamba relative to overall herbicide use 

in soybean production is relatively low, contributing less than 15% to the overall herbicide use in 

glyphosate-tolerant soybean production.

While an increase in overall herbicide use in soybean growing areas is projected for the 

commercialization of DT soybean, assuming growers adopt recommended weed management 

practices, these practices provide numerous economic and environmental benefits which are detailed 

in this Environmental Report and Appendices B, C, and F thereto, and summarized below:

 Providing an effective tool for sustainable management of glyphosate resistant weeds; 
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 Mitigating the potential for the evolution and development of weed resistance for all classes 

of herbicides used in soybean; 

 Improving the consistency of control over hard-to-control weeds, thereby reducing the 

potential for new resistant biotypes to develop;

 Increasing application flexibility; 

 Preserving the benefits of the glyphosate-tolerant weed control system; and

 Preserving the many environmental and economic benefits of conservation tillage 

Furthermore, the projected increase in the amount of dicamba used in soybean production is not 

expected to result in adverse impacts to human health or the environment. The EPA regulates 

pesticide use and is required under the Federal Insecticide Fungicide and Rodenticide Act (FIFRA) 

to reach a conclusion of no unreasonable adverse effects to human health and the environment 

before any application of dicamba can be made on DT soybean (see Appendices E and F to this 

Environmental Report). Monsanto has submitted an application to EPA to approve the use of 

dicamba on DT soybean. EPA concluded in the dicamba Reregistration Eligibility Decision 

document that all then-registered uses of dicamba can be used without resulting in unreasonable 

adverse effects when used according to the approved legal label (EPA, 2009). Because the use 

pattern for dicamba on DT soybean is consistent with the use patterns and assumptions on 

herbicide use intensification evaluated in the RED, any projected increase in dicamba use from the 

commercialization of DT soybean is not expected to result in potential adverse impacts to the 

human health or the environment, and EPA is expected to reconfirm dicamba’s safety as part of its 

review of the Monsanto application.
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Table A-19. Net impact of Dicamba-Tolerant soybean on overall herbicide use

2015 (Projected)

With Dicamba-tolerant soybean

Total Acres Treated (TAT)

(000 acres / year)

Total lbs a.i.

(000 lbs a.i. /year)

Projected increase in dicamba use (+) 47,112a(+) 20,546a

PRE herbicides replaced by dicamba (-) 6,816b(-) 3,616c

POST herbicides replaced by dicamba (-) 13,079d(-) 1,596e

Net change in herbicide use with 

introduction of dicamba (+) 27,217 (+)15,334

Without Dicamba-tolerant soybean

Projected total of non-glyphosate 

herbicides 138,938f33,844g

Projected total of glyphosate herbicides 112,800 h99,186 i

Total - non-glyphosate plus 

glyphosate 251,738 133,030

Dicamba as % of herbicide use in absence 

of dicamba 11% 12%

a Table A-14 

b Table A-15

c Table A-17 

d Table A-16 

e Table A-18 

f The sum of PRE and POST non-glyphosate herbicide projections from Table A-10 and Table A-11, respectively.

g

Projected total non-glyphosate herbicides is the sum of 2015 PRE and POST non-glyphosate herbicide projections 

for total lbs a.i. Projected total lbs a.i. are based on the 2011 unpublished market research data for total lbs a.i. 

(Monsanto, 2011) and the projected growth rates of 100% and 132% for the PRE and POST segments, respectively.

h The sum of PRE and POST glyphosate herbicide projections from Table A-10 and Table A-11, respectively.

i

Projected total glyphosate herbicides is the sum of 2015 PRE and POST glyphosate herbicide projections for total 

lbs a.i. Projected total lbs a.i. are based on the 2011 unpublished market research data for total lbs a.i. (Monsanto, 

2011) and the projected growth rates of 100% and 132% for the PRE and POST segments, respectively.
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A.3.7. Comparative Analysis of Dicamba and Alternative Soybean Herbicides 

A.3.7.1. Introduction

Dicamba is a selective broadleaf herbicide belonging to the auxin agonist class, the oldest known 

class of synthetic herbicides, and is a member of the benzoic acids sub-group. Dicamba mimics the 

action of the plant hormone indole acetic acid and causes rapid uncontrolled cell division, and 

growth leading to plant death. Dicamba has been registered for agricultural uses in the U.S. since 

1967 and has been widely used in agricultural production for over forty years. Dicamba is presently 

approved for use on asparagus, corn, cotton, grass seed production, pasture and rangeland grasses, 

small cereals including barley, oats, rye, and wheat, sorghum, soybean, and sugarcane. Dicamba is 

also used for industrial vegetation management (e.g., forestry and roadsides), professional turf 

management (e.g., golf courses, sports complexes), and residential turf (U.S. EPA, 2009b). 

Monsanto Company has developed a biotechnology-derived DT soybean that is tolerant to dicamba 

(3,6-dichloro-2-methoxybenzoic acid). DT soybean offers growers expanded use of dicamba in 

soybean production. The excellent crop tolerance of DT soybean to dicamba facilitates a wider 

window of application in soybean, allowing a preemergence application up to emergence (cracking) 

and in-crop postemergence applications through the R1/R2 stage of growth. Dicamba provides 

effective control of over 95 annual and biennial weed species, and control or suppression of over 

100 perennial broadleaf and woody plant species. The most common weeds found in soybean fields 

are listed in Tables A-14 (Midwest region), A-15 (Southeast region), and A-16 (Eastern Coastal 

region). Many of those weeds can be controlled effectively by dicamba. DT soybean will be 

combined with MON 89788 (Roundup Ready 2 Yield soybean) utilizing traditional breeding 

techniques. The combination of herbicide-tolerance traits allows the use of dicamba and glyphosate 

herbicides in an integrated weed management program to control a broad spectrum of grass and 

broadleaf weed species, such that the two herbicides can be used in sequence or tank-mixed. 

Monsanto has submitted an application to the Environmental Protection Agency (U.S. EPA) to 

register this new use pattern for dicamba on DT soybean (OPP Decision Number D-432752). 

The availability of DT soybean integrated into the Roundup Ready soybean system will result in a 

simple and effective dual mode-of-action herbicide system that will control hard-to-control 

broadleaf weeds, assist in the management of resistant broadleaf weeds, including glyphosateresistant biotypes, and subsequently displace some herbicides currently used in soybeans today 

(referred to here as alternative herbicides). 

The intent of this comparative analysis is to define current herbicide use in U.S. soybean production, 

and to compare dicamba’s efficacy and human health and environmental properties to herbicides 

currently used by growers for weed control. In order for a pesticide (herbicide) to be registered by 

EPA the U.S. EPA must conclude that the herbicide, when used according to the label, does not 

pose an unreasonable risk to humans or the environment, and, in order to establish a tolerance for 

the use of a herbicide on a food or feed crop, find there is a reasonable certainty of no harm to 

human health from aggregate non-occupational (food, water and residential/recreational) exposures 

to the herbicide. Consequently, EPA has determined that all alternative herbicides registered for use 

in soybean do not pose an unreasonable risk to humans or the environment. 

Nonetheless, in some instances dicamba offers a reduction in risk potential in the same risk category 

compared to some alternative herbicides (e.g., acute human risk, aquatic plant risks). In other 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 401 of 946

instances, dicamba presents a similar risk potential compared to the alternatives. In some instances, 

dicamba presents a greater risk potential compared to some alternatives. 

Overall, the use of dicamba on DT soybean incorporated into the Roundup Ready soybean system 

will offer a benefit compared to alternative soybean herbicides. For human health, aquatic plants 

and animals, and for preemergence application flexibility,. dicamba use on DT soybean provides an 

overall reduction of potential risk (combination of “Yes” and “No” entries in TableA-24) compared 

to the alternatives, except for flumiclorac-pentyl. Specifically: 

 Formulations based on the diglycolamine salt of dicamba, such as Clarity® or M1691 

herbicide, have favorable acute toxicity profiles that reduce the risk of acute adverse effects 

for applicators, agricultural workers and bystanders compared to six alternative herbicide 

products.

 The active ingredient (a.i.) dicamba has favorable chronic, reproduction, carcinogenicity and 

developmental toxicity characteristics, which reduce the potential for risks from exposure to 

applicators, agricultural workers and consumers, compared to exposure from eight 

alternative herbicide products.

 Dicamba has very low toxicity to fish and aquatic invertebrates, and based on EPA high-end 

exposure screening level assessment methodology, will not affect listed and non-listed 

aquatic plants and animals, which reduces the potential risk to aquatic organisms as 

compared to seven alternative products.

 Dicamba use on DT soybean will strengthen and extend the benefits of glyphosate-based 

weed control in soybean, which has many well-known and recognized environmental and 

human health benefits, as acknowledged in previous EPA Office of Pesticide Programs 

(OPP) decisions to grant reduced risk status to multiple glyphosate-tolerant crop uses, 

including corn, canola, and sugar beet. Additionally, the use of glyphosate-based weed 

control in soybean has provided growers with more profit opportunities than conventional 

soybean by reducing input costs (Gianessi, 2005). By utilizing both active ingredients, which 

have different herbicidal modes-of- action, the risk to soybean production posed by weeds 

that are hard-to-control with glyphosate alone, or have developed resistant to glyphosate, is 

reduced. Hard-to-control weeds generally require a higher rate and/or application at a 

smaller growth stage in order to consistently achieve commercially acceptable control, and 

includes copperleaf, hemp sesbania, morningglory, prickly sida, velvetleaf, waterhemp, and a 

number of other broadleaf and grassy weeds. (Table II.B-3 through Table II.B-5)

 Dicamba use on DT soybean will also provide growers with the option to use an herbicide 

with a different mode-of-action to manage weed species (e.g., Pigweed) where certain 

biotypes have demonstrated resistance to herbicide classes other than glyphosate, such as 

protoporphyrinogen oxidase (PPO) or acetolactate synthase (ALS) inhibitors. Herbicide 

resistant weeds are those listed on the International Survey of Resistant Weeds website 

(www.weedscience.org).

 Dicamba use on DT soybean will reduce the risk to soybean production that ensues when 

growers utilize alternate herbicides that have long rotation restriction periods or pose 

potential for substantial crop injury and loss of yield. 

 Planting glyphosate tolerant soybean, thereby allowing the use of glyphosate to effectively 

control weeds in no-till fields, has made no-till a viable production system for soybean 

(Pedersen, 2008). The use of dicamba on DT soybean will reduce the risk of growers 

reverting back to conventional tillage practices from conservation tillage practices due to 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 402 of 946

concerns over weed control or resistance, and thereby foster continued adoption of 

conservation tillage practices, which is an important goal for the agro-ecosystem and the 

long-term sustainability of U.S. agriculture. The integration of DT soybean into the 

Roundup Ready soybean system will allow the flexibility to incorporate a second herbicide 

and mode-of-action in preemergent or postemergent applications and support the continued 

use of conservation tillage production.

In conclusion, dicamba provides a similar, and in some cases a more benign, comparative risk profile 

compared to other alternative herbicide products; the use of dicamba on DT soybean will positively 

impact integrated pest management practices and sustainability of soybean production in the United 

States by providing a valuable weed management tool for this important agricultural crop. Dicamba 

imparts greater flexibility and weed control options and will help to mitigate the potential for 

selection for herbicide-resistant weed biotypes for all herbicide modes-of-action (i.e., ALS, HPPD, 

PPO, glyphosate) currently registered for use in soybean. DT soybean will continue to support 

adoption of no-till and conservational tillage practices. 

Table A-20. Common Weeds in Soybean Production: Midwest Region

Foxtail spp. (12)1 Ragweed, giant (3) Dandelion (1)

Pigweed spp. (11) Shattercane (3) Johnson grass (1)

Velvetleaf (11) Quackgrass (3) Milkweed, honeyvine (1)

Lambsquarters (10) Buckwheat, wild (2) Nightshade, hairy (1)

Cocklebur (9) Crabgrass spp. (2) Oats, wild (1)

Ragweed, common (7) Kochia (2) Pokeweed, common (1)

Smartweed spp. (6) Mustard, wild (2) Prickly sida (1)

Morningglory spp. (5) Nightshade, Eastern black (2) Proso millet, wild (1)

Sunflower, spp. (5) Palmer pigweed (2) Sandbur, field (1)

Waterhemp spp. (5) Canada thistle (1) Venice mallow (1)

Horseweed (marestail) (3) Chickweed (1) Volunteer cereal (1)

Panicum, fall (3) Cupgrass, woolly (1) Volunteer corn (1)

1 Number provided in parenthesis is the number of states out of the thirteen total states in the Midwest 

region reporting each weed as a common weed. 

Sources: 

IL: University of Illinois (2002) and Aaron Hager, Extension Weed Specialist, University of Illinois -

Personal Communication (2006).

IN: 2003-2005 Statewide Purdue Horseweed Weed Survey, Special database query and personal 

communication (2006), Bill Johnson, Extension Weed Specialist, Purdue University.

IA, MN, OH, WI: WSSA, 1992. 

KS: Dallas Petersen, Extension Weed Specialist, Kansas State - Personal communication (2006).

KY, MO: Webster et al., 2005.

MI: Davis et al., 2005. 

NE: Alex Martin, Extension Weed Specialist, University of Nebraska – Personal communication (2006).

ND: Zollinger, 2000.

SD: Michael Moechnig, Extension Weed Specialist, South Dakota State University – Personal 

communication (2006).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 403 of 946

Table A-21. Common Weeds in Soybean Production: Southeast Region

Morningglory spp. (8)1 Goosegrass (3) Cutleaf evening-primrose (1)

Crabgrass spp. (6) Johnsongrass (3) Groundcherry (1)

Prickly sida (6) Ragweed, common (3) Henbit (1)

Nutsedge spp. (6) Cocklebur (2) Lambsquarters (1)

Sicklepod (5) Florida beggarweed (2) Ragweed, giant (1)

Signalgrass, broadleaf (5) Hemp sesbania (2) Smartweed (1)

Palmer pigweed (4) Horseweed (marestail) (2) Spurge, nodding/hyssop (1)

Pigweed spp. (4) Texas millet (2) Spurge, Prostrate (1)

Barnyard grass (3) Browntop millet (1) Tropic croton (1)

Florida pusely (3) Copperleaf, hophorn (1)

1 Number provided in parenthesis is the number of states out of the eight total states in the Southeast 

region reporting each weed as a common weed. 

Sources:

AL, AR, GA, LA, NC, SC: Webster et al., 2009. 

MS, TN: Webster et al., 2005.

Table A-22. Common Weeds in Soybean Production: Eastern Coastal Region

Foxtail spp. (6)1 Morningglory spp. (4) Dandelion (1)

Ragweed, common (6) Panicum, fall (4) Goosegrass (1)

Velvetleaf (6) Crabgrass spp. (3) Johnson grass (1)

Lambsquarters (5) Nutsedge spp. (3) Nightshade, Eastern black (1)

Pigweed spp. (5) Quackgrass (2) Prickly sida (1)

Cocklebur (4) Canada thistle (1) Shattercane (1)

Jimson weed (4) Burcucumber (1) Smartweed spp. (1)

1 Number provided in parenthesis is the number of states out of the six total states in the Eastern 

Coastal region reporting each weed as a common weed. Data were not available for DE in soybean. 

Sources:

DE, MD, NJ, PA: WSSA, 1992. 

NY: Russell Hahn, Extension Weed Specialist, Cornell University – Personal Communication 

(2006).

VA: Webster et al., 2009.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 404 of 946

A.3.7.2. Properties of Alternative Herbicide Products

Ninety-seven percent (97%) of soybean treated acres receive an application of glyphosate, and the 

remaining acres are treated with more than 25 other active ingredients. In some of the soybean 

acres, these other active ingredients are applied on acres that also receive a glyphosate application. 

The ten most widely used herbicides are shown in Table A-23. Integration of DT soybean into the 

Roundup Ready soybean system and the subsequent use of dicamba will result in the displacement 

of some currently used, or foreseeable future use herbicides, and therefore the properties of these 

alternative herbicides are summarized in this section to provide a baseline for comparison to 

dicamba use on DT soybean. 

Table A-23. Ten Most Widely Used Alternative Herbicides in U.S. Soybean Production in 

2012

Herbicide Treated acres 

(millions)1

Pounds Applied

(million lbs)1

2,4-D (acid, salts, and esters, 

combined)

11.58 6.02

Flumioxazin 8.49 1.56

Imazethapyr 3.86 1.35

cloransulam-methyl 3.09 0.60

chlorimuron-ethyl 8.49 0.52

Fomesafen 6.18 0.22

Clethodim 6.95 0.19

pendimethalin 1.54 0.08

Tribenuron 0.77 0.04

flumiclorac-pentyl 0.77 0.01

1 USDA-NASS, 2013

Table A-24 summarizes key information from alternate herbicide product labels. Table A-25 lists 

the eighteen active ingredients that make up the products in Table A-24. 2,4-D, being used primarily 

as a pre-plant application, is the most widely-used herbicide in this alternate herbicide list,

representing about 10% of treated acres; whereas acifluorfen, carfentrazone-ethyl, and flufenacet are 

the least used among these, representing <0.5% of treated acres. Mesotrione has not been used in 

soybean production previously; the use on soybean was only recently registered by the EPA (2009d). 

Table A-25 also lists general regulatory information about each herbicide. Note that only paraquat is 

classified as a Restricted Use pesticide among this group, on the basis of acute toxicological concern. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 405 of 946

Table A-24. Dicamba and Alternative Registered Soybean Herbicides

Brand

(U.S. EPA Reg. 

No.) Active Ingredient Signal Word1

Active Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean lb/a 

(season)

Label Warnings or Special 

Directions4

Clarity (7969-137) Dicamba Caution 4.0 lb a.e./gal 24 hr 1.0 1 2.0 1 Known to leach; 50-foot buffer to 

wells; Runoff advisory; Drift 

advisory; State-specific limitations; 

Soil type limitations; Maximum crop 

rotation interval 3 – 6 months.

Aim® (279-3241) Carfentrazone-ethyl Caution 2 lb/gal 12 hr 0.008 5 0.023 “toxic to fish”; “toxic to algae”; V3 

- V10; do not feed foliage; some 

burn injury

Authority® First 

DF (279-3246)

Sulfentrazone Caution 0.62 lb/lb 12 hr 0.31 0.31 “known to leach”; “toxic to marine 

/ estuarine invertebrates”; 65-day 

PHI; crop rotation restrictions, up 

to 30 mts; soil O.M. limits (sands 

<1% organic matter)

Cloransulam-methyl 0.08 lb/lb 0.04 0.04

Authority MTZ 

(279-3340)

Sulfentrazone Caution 0.18 lb/lb 12 hr 0.028 0.046 “known to leach”; “toxic to marine 

/ estuarine invertebrates”; 120-day 

PHI (not Over The Top); sensitive 

varieties, injury possible

Metribuzin 0.27 lb/lb 0.042 0.07

Basagran®

(7969-45)

Bentazon Caution 4 lb/gal 48 hr 1 2 “known to leach”; 30-day PHI for 

feeding treated forage and hay; 

minor injury

Butoxone® 7500 

(71368-49)

2,4-DB Caution 0.75 lb/lb 48 hr 0.375 soil type limits

Butyrac® 200 

(42750-38)

2,4-DB DMA salt Danger 2 lb/gal 48 hr 0.4 0.4 “toxic to fish”; 60-day PHI; injury 

may occur, especially with tank 

mixtures
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 406 of 946

Table A-24 (continued). Dicamba and Alternative Registered Soybean Herbicides

Brand

(U.S. EPA Reg. 

No.) Active Ingredient Signal Word1

Active Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean lb/a 

(season)

Label Warnings or Special 

Directions4

Cadet® (279-

3338)

Fluthiacet-methyl Warning 0.91 lb/gal 12 hr 0.0065 0.009 do not feed foliage; minor injury

Callisto® (100-

1131) 

Mesotrione Caution 4 lb/gal 12 hr 0.1875 0.1875 “high potential for runoff”; crop 

rotation restrictions up to 18 mts; 

“transient bleaching” may occur; 

pre-emergence use only, no in crop 

use

Classic® (352-

436)

Chlorimuron-ethyl Caution 0.75 lb/lb 12 hr 0.14 0.14 6 60-day PHI; crop rotation 

restrictions up to 30 mts and 

complicated description of 3 

different intervals specific to US 

regions and soil pH; do not feed 

foliage; soil type limits; “temporary 

leaf yellowing”

Cobra® (59369-

34)

Lactofen Danger 2 lb/gal 12 hr 0.2 0.4 6 “toxic to fish”; do not apply past 

soybean growth stage R6/45-day 

PHI; minor injury

Extreme ®

(241-405)

Imazethapyr Warning 0.17 lb/gal 48 hr 0.064 6 0.064 6 “properties & characteristics 

associated with chemicals detected 

in ground water”; crop rotation 

limits

Glyphosate-IPA 2 lb/gal 0.75 0.75

FirstRate 

(62719-275)

Cloransulam-methyl Caution 0.84 lb/lb 12 hr 0.04 0.055 65-day PHI; crop rotation 

restrictions up to 30 mts; soil types; 

14-day forage and hay feeding 

restriction
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 407 of 946

Table A-24 (continued). Dicamba and Alternative Registered Soybean Herbicides 

Brand 

(U.S. EPA 

Reg. No.) Active Ingredient Signal Word1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. Soybean 

lb/a (season)

Label Warnings or Special 

Directions4

Flexstar ®

(100-1101)

Fomesafen Warning 1.88 lb/gal 24 hr 0.35 0.375 6 “cause tumors”; “known to leach”; 45-

day PHI; do not feed foliage; crop 

rotation limits

Gangster ® Copack (59639-

131)

Flumioxazin Caution 51% 12 hr 0.096 0.096 “toxic to aquatic invertebrates”; 

“Preemergent only”; “properties & 

characteristics Associated with 

chemicals detected in ground water”; 

“toxic to invertebrates.”

Cloransulam-methyl 84% 0.032 0.032

Gramaoxone 

Inteon ® (100-

1217)

Paraquat dichloride Danger 2 lb/gal (cation 

basis)

12 hr 1.5 2.9 “toxic to wildlife”; Restricted Use; no 

Over-the-Top use

Ignite® (264-

829)

GlufosinateammoniumWarning 2.34 lb/gal 12 hr 0.66 0.8 “runoff potential”; “toxic to vascular 

plants”; 70-day PHI; some crop 

rotation limits up to 180 days; only 

Over-the-Top to Liberty Link soybean

Liberty® (264-

660)

GlufosinateammoniumWarning 1.67 lb/gal 12 hr 0.44 0.8 “runoff potential”; “toxic to vascular 

plants”; 70-day PHI; do not feed 

foliage; crop rotation limits up to 120 

days;

Phoenix®

(59639-118)

Lactofen Caution 2 lb/gal 12 hr 0.3 0.4 6 “toxic to fish”; Do not apply past crop 

growth stage R6 / 45-day PHI; minor 

injury

Pursuit® (241-

310)

Imazethapyr Caution 2 lb/gal 4 hr 0.063 0.063 “properties & characteristics associated 

with chemicals detected in ground 

water”; 85-day PHI; do not feed forage 

and hay
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 408 of 946

Table A-24 (continued). Dicamba and Alternative Registered Soybean Herbicides 

Brand

(U.S. EPA Reg. 

No.) Active Ingredient

Signal Word

1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean lb/a 

(season)

Label Warnings or Special 

Directions4

Pursuit® Plus 

(241-331)

Pendimethalin Caution 2.7 lb/gal 24 hr 0.84 0.84 “properties & characteristics 

associated with chemicals detected in 

ground water”; “toxic to fish”; 85-day 

PHI; crop rotation limits up to 40 

months

Imazethapyr 0.2 lb/gal 0.063 0.063

Raptor ® (241-379) Imazamox-ammonium Caution 1 lb/gal 4 hr 0.04 0.04 “phytotoxic to all plants”; plantback / 

crop rotation limits up to 26 months, 

two regions with complicated 

warnings

Reflex® (100-993) Fomesafen Danger 2 lb/gal 24 hr 0.375 0.375 6 “known to leach”; 45-day PHI; crop 

rotation limits up to 18 mts; minor 

injury, significant geographical 

restrictions (5 regions each with 

different rate structure)

Resource®

(59639-82)

Flumiclorac-pentyl Warning 0.86 lb/gal 12 hr 0.081 0.11 “toxic to shrimp”; 60-day PHI; do 

not feed forage or hay to livestock; 

temporary spotting or burn to 

soybean

Scepter ®70 DG 

(241-306)

Imazaquin Caution 0.7 lb/lb 12 hr 0.123 0.123 6 “properties & characteristics 

associated with chemicals detected in 

ground water”; 90-day PHI; do not 

feed forage or hay to livestock; crop 

rotation limits up to 40 mts; regional 

limitations (3 regions)
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 409 of 946

Table A-24 (continued). Dicamba and Alternative Registered Soybean Herbicides

Brand

(U.S. EPA Reg. 

No.) Active Ingredient

Signal Word

1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean lb/a 

(season)

Label Warnings or Special 

Directions4

Sencor® (DF 75%) 

(264-738)

Metribuzin Caution 0.75lb/lb 12 hr 0.66 6 1.3 6 “can seep or leach”; 70-day grain PHI; 

40-day PHI on feeding forage to 

livestock; no Over-the-Top 

application, directed spray OK; injury 

in high pH or low O.M. soils or on 

certain crop varieties, crop rotation 

limits up to 18 mts

Synchrony® XP 

(352-648)

Thifensulfuron Caution 0.069 lb/lb 12 hr 0.013 0.013 45-day planting restriction applied 

prior to soybean planting/emergence; 

60-day PHI; complicated crop rotation 

restrictions (3 regions, 4 intervals) with 

limits up to 30 mts; do not feed forage 

or hay to livestock; soil types; injury if 

adjuvants or tank mixed

UltraBlazer 

(70506-60)

Acifluorfen sodium Danger 2 lb/gal 48 hr 0.374 0.5 50-day PHI; minor injury

Chlorimuron-ethyl 0.215 lb/lb 0.04 0.04

Valor® SX 

(59639-99)

Flumioxazin Caution 0.51 lb/lb 12 hr 0.096 0.096 “runoff potential”; “toxic to aquatic 

invertebrates”; preemergence use only, 

no in crop use; do not feed forage or 

hay to livestock; crop rotation limit up 

to 18 mts. & soil type limits; injury 

under cool wet conditions or poorly 

drained soil; restrictions on use with 

flufenacet, alachlor, metolachlor, or 

dimenthenamid
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 410 of 946

Table A-24 (continued). Dicamba and Alternative Registered Soybean Herbicides

Brand

(U.S. EPA Reg. 

No.) Active Ingredient

Signal Word

1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean lb/a 

(season)

Label Warnings or Special 

Directions4

Valor® XLT 

(59639-117)

Flumioxazin Caution 0.3 lb/lb 12 hr 0.094 0.094 “toxic to aquatic invertebrates”; 

preemergence only, no in crop use; 

do not feed forage or hay to livestock; 

crop rotation limits up to 30 mts; 

injury under cool wet conditions or 

poorly drained soil

Chlorimuron-ethyl 0.103 lb/lb 0.032 0.032

Weedone® (650, 

638, LV4, LV6) 

and other 2,4-D 

brands (71368-3, -

6, -10, -11, -14, -

19)

2,4-D; 2,4-D salts; 2,4-

D esters

Varies Varies 0.93 0.93 Weedone 650 as an example: “toxic 

to aquatic invertebrates”; do not use 

on sandy soils (<1% O. M.); preplant 

to emerged weeds only, no in crop 

use; do not feed forage or hay to 

livestock

1 The EPA-required statement to convey to applicators the overall acute toxicity hazard posed by the product. Caution is more favorable than Warning, which is more favorable than 

Danger.

2 The period of time following application during which worker reentry into the treated area is restricted, according to EPA’s Worker Protection Standard (WPS).

3 The highest single-treatment and seasonal rates that can be applied to soybean according to the product Directions for Use label.

4 Lists specific statements extracted from the product label that represent specific hazards or limitations that may reduce the utility of the product for soybean weed control

5 Higher rates with directed / hooded sprayers.

6 Regional or soil type limitations may lower this rate.

7 Soybean label not yet publically available. Corn label comments are cited

PHI – preharvest interval, O. M. – organic matter, mts - months.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 411 of 946

Table A-25. Active Ingredients Contained in Alternative Herbicides

Active Ingredient

First 

Registered1

2006 Treated 

Soybean 

Acreage

(%)2

Registration 

Review 

Status3 RED Date4

Max. 

Soybean lb/a 

(single 

treatment)5

Max. 

Soybean 

lb/a 

(season)

Tolerances 

(40 CFR 

180)6

Restricted 

Use7

glyphosate salts 3-May-76 97 open 2009 Sep-93 1.5 6 364 No

dicamba-diglycolamine 

salt

2-Feb-56 <0.5 NA Jun-09, corrected 1

9 29 227 No

2,4-D acid, salts, and 

esters

3-Jun-52 10 2013 Jun-05 0.93 0.93 142 No

Flumioxazin 12-Apr-2001 3 unscheduled NA 0.096 0.096 568 No

Imazethapyr 30-Jan-87 3 2014 Jun-06 0.0648 0.0648 447 No

cloransulam-methyl 29-Oct-1997 1 2011 NA 0.04 0.055 514 No

chlorimuron-ethyl 4-Apr-86 4 2011 Sep-04 TRED 0.14 0.148 429 No

Fomesafen 10-Apr-87 2 open 2007 TRED Aug-07 0.375 0.3758 433 No

flumiclorac-pentyl 23-Mar-94 1 open 2009 Aug-05 TRED 0.081 0.11 477 No

Sulfentrazone 22-Nov-93 1 open 2009 NA 0.31 0.31 498 No

Thifensulfuron 25-Apr-86 1 2011 NA 0.013 0.013 439 No

Imazaquin 20-Mar-86 1 2014 TRED Dec-05 0.123 0.1238 426 No

imazamox-ammonium 17-Apr-95 <0.5 2014 NA 0.04 0.04 1223 No

paraquat dichloride 8-Jan-80 1 2012 Aug-97 1.0 2.9 205 Yes

Lactofen 1-Apr-87 <0.5 open 2007 TRED Sep-03 0.3 0.4 432 No

glufosinate-ammonium 29-May-91 <0.5 open 2008 NA 0.66 0.8 473 No

2,4-DB 30-Jun-66 <0.5 2014 Jan-05 0.4 0.4 331 No

fluthiacet-methyl 14-Apr-99 <0.5 unknown NA 0.0065 0.009 551 No

acifluorfen sodium 29-May-81 <0.5 unscheduled Sep-09 0.374 0.5 383 No

Mesotrione 4-Jun-01 0.0 unscheduled NA 0.1875 0.1875 571 No
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 412 of 946

TRED denotes Tolerance Reregistration Eligibility Decision

1 The date the herbicide was first approved for any use (e.g., industrial) by U.S. EPA.

2 The percentage of the herbicide-treated soybean acres that were treated with each herbicide in AR, IA, IL, IN, KS, KY, LA, MI, MN, MS, MO, NE, NC, ND, OH, 

SD, TN, VA, and WI in 2006 (USDA-NASS, 2007b) .

3 The herbicide’s progress in the ongoing EPA program named as Registration Review. Year indicates when the official docket was or will be opened. EPA is required 

by law to re-evaluate pesticides periodically, generally every 10-15 years.

4 The date when EPA issued a Reregistration Eligibility Decision document. Reregistration was an earlier re-evaluation program designed to ensure that supporting 

data are up-to-date for a.i.s first registered before 1984. TRED means Tolerance Reassessment Eligibility Decision, which refers to an alternative review path that 

some post-1984 a.i.s followed.

5 The maximum amount of the herbicide that can be applied to soybean in a single treatment or during the entire season, according to product labels.

6 The number of the paragraph in the Code of Federal Regulations where that herbicide’s food and feed tolerances are listed.

7 An EPA pesticide classification that restricts a product, or its uses, to use by a certificated pesticide applicator or under the direct supervision of a certified applicator. 

See 40 CFR 152.160.

8 Regional or soil type limitations may lower this rate.

9 Maximum treatment rates for the proposed dicamba label.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 413 of 946

A.3.7.2.1. Human Health Effects of Alternative Herbicide Products

Table A-26 provides information concerning human health parameters for each alternative herbicide 

compared to dicamba. The listed parameters include:

 Acute Toxicity Categories for the herbicide.

 Cancer Classification of the herbicide.

 FQPA (Food Quality Protection Act) safety factor employed in EPA’s risk assessment 

process for the herbicide.

 Level of Exposure representing the acceptable safe range for acute (acute population adjusted 

dose, aPAD) and chronic (chronic population adjusted dose, cPAD) exposures. 

 Extent to which all presently approved uses exhaust the acceptable safe exposure range (% 

aPAD and % cPAD utilized for the most highly exposed population subgroups), according to 

recent Federal Register Rules or other public risk assessment documents.

A variety of chemical-specific public data sources were used to compile this comparison (See 

Alternative Herbicide-Specific References). Columns 9 to 11 in Table A-26 (to the right of the 

vertical gray bar) pertain to the use of the herbicide in soybean, specifically:

 The established soybean seed food tolerance in 40 CFR 180 that supports the uses in 

soybean.

 The Theoretical Maximum Residue Concentration (TMRC) arising from this soybean 

tolerance using the DEEM dietary exposure software, assuming that residues are at tolerance 

levels and that 100% of the crop has been treated.

 The percentage of the acceptable chronic exposure (cPAD) that is contributed by the soybean 

TMRC dietary exposure.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 414 of 946

Table A-26. Human Health Risk Parameters for Alternative Herbicides

Active Ingredient

Acute (Oral, Dermal, 

Inhalation, Eye Irr., 

Skin Irr., Sens.)1

Cancer

Classification2

cPAD 

mg/kg/day

3

% cPAD 

Utilized4,5

aPAD 

mg/kg/day

6

% aPAD 

Utilized

6,5

FQPA 

SF7

Soy Seed 

Tol. 

(ppm) 8,9

Soybean diet 

exposure 

μg/kg/day

5,8,10

% Soybean 

diet 

exposure / 

cPAD 8,11

glyphosate acid / 

potassium salt

IV / IV / NA / II / IV / 

N; IV / IV / III / III / 

IV / N

E 1.75 7 NA NA 1X 20 33.24 1.90%

dicamba acid

diglycolamine salt12

III / III / IV / II / II / 

N; III / III / IV / III / 

III / N

not likely 0.45 6.6 1 11 1X 10 16.62 3.69%

2,4-D acid /salts / 

esters

III / III / III/ I / III-IV 

/ N; 

III / III / IV / III / IV / 

N

D 0.005 38 0.067 58 1X 0.02 0.03 0.66%

flumioxazin IV/III/IV/III/IV/N not likely 0.02 18 0.03 8 1X 0.02 0.03 0.17%

imazethapyr

IV / III / IV / IV / III / 

N

not likely 2.5 < 1 NA NA 1X 0.1 0.17 0.01%

cloransulam-methyl

IV / III / III / III / IV / 

N

not likely 0.1 <1 NA NA 1X 0.02 0.03 0.03%

chlorimuron-ethyl IV / III / IV / III / IV / 

N

not likely 0.09 0 NA NA 1X 0.05 0.08 0.09%

fomesafen III / II /III / I / II-III / 

Y

not likely 0.0025 31 NA NA 1X 0.05 0.08 3.32%

flumiclorac-pentyl IV / III/ IV/ IV/ II/ Y no evidence 1 < 0.01 NA NA 1X 0.01 0.02 0.00%

sulfentrazone III/ III / IV / I / IV / Y not likely 0.14 <1 0.25 1 1X 0.05 0.08 0.06%

thifensulfuron IV / III / IV / IV / III / 

N

not likely 0.07 <1 1.59 <0.1 1X 0.1 0.17 0.24%

imazaquin IV / III / III / IV / IV / 

N

no evidence 0.25 <1 NA NA 1X 0.05 0.08 0.03%

imazamox-ammonium

IV / III / IV / III / IV / 

N

not likely NA NA NA NA 1X ex '03 NA NA

paraquat dichloride II / III / I /II / IV / N E 0.00045 26 0.0042 66 1X 0.7 1.16 258.53%
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Table A-26 (continued). Human Health Risk Parameters for Alternative Herbicides 

Active Ingredient

Acute (Oral, Dermal, 

Inhalation, Eye Irr., 

Skin Irr., Sens.)1

Cancer

Classification2

cPAD 

mg/kg/day

3

% cPAD 

Utilized4,5

aPAD 

mg/kg/day

6

% aPAD 

Utilized

6,5

FQPA 

SF7

Soy Seed 

Tol. 

(ppm) 8,9

Soybean diet 

exposure 

μg/kg/day

5,8,10

% Soybean 

diet 

exposure / 

cPAD 8,11

Lactofen IV / III / IV / III / IV / 

N

likely/unlikely 0.008 <0.1 0.17 <0.1 3X (A) 0.01 0.02 0.21%

glufosinateammoniumIII / III / III / III / IV / 

N

no evid. of 0.006 27 0.0063 48 1X 2 3.32 55.40%

2,4-DB III / III / IV / III / IV / not likely 0.03 2 0.6 <1 1X 0.5 0.83 2.77%

fluthiacet-methyl IV / III / IV / IV / IV 

/N

likely 

(7.5x10-7)

0.001 <1 NA NA 1X 0.01 0.02 1.66%

acifluorfen sodium III / III / IV / I / II / N likely/unlikely 0.013 <1 0.02 <1

1X/3X

/10X

0.1 0.17 1.28%

Mesotrione IV / III / IV / III / IV / 

N

not likely 0.007 5.8 NA NA 3X 0.01 0.02 0.23%

Sources of the information summarized in this table are listed in the Alternative Herbicide Specific References Section.

N denotes negative for dermal sensitization

NA stands for not applicable.

1 EPA categories for the standard six acute toxicity tests of the active ingredient. Categories I and IV denote the least and most favorable findings, respectively. 

Category I findings are highlighted in bold font.

2 The conclusion reached by the EPA Office of Pesticide Programs Cancer Assessment Review Committee. The system of classification has changed over the years, 

resulting in a combination of different terminology. Generally, Group E, “not likely” or “no evid.” are the most favorable conclusions, Group D indicates some 

uncertainty, and “likely/not likely” or “likely” indicate that a potential to induce cancer exists. More information can be found at 

http://www.epa.gov/opp00001/health/cancerfs.htm. “Likely” findings are highlighted in bold font.

3 The EPA-determined chronic Population Adjusted Dose, against which chronic exposure, primarily from combined food and water residues, are compared for 

human health risk assessment. This key risk assessment parameter is derived from consideration of all the chronic toxicity studies, and includes all necessary safety 

factors. Higher values indicate herbicides with less severe chronic toxicity effects.

4 The percentage of the cPAD that is represented by all presently approved uses of that herbicide for the most highly-exposed population subgroup. It is calculated by 

summing estimated chronic exposures from dietary and water, and dividing by the level of exposure that is considered safe (i.e., cPAD). Lower percentages indicate 

that current estimated exposure is a smaller proportion of the safe level, and therefore implies a greater margin of safety. EPA presents this calculation when new risk 

assessments are conducted, such as when a new food tolerance is petitioned.

5 Most highly exposed population subgroup.

6 The acute risk assessment parameters correspond to those described above for chronic exposure. In some cases, EPA’s review of the acute toxicity testing does not 

result in an acute effect of concern, and no aPAD is needed, indicated in the table as NA.
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7 The Safety Factor EPA has utilized according to the requirements of the Food Quality Protection Act. FQPA that requires EPA utilize an additional 10-fold (10x) 

safety factor to protect infants and children, unless the scientific results indicate that a different level is protective. If the database is complete, and the reproductive 

and developmental toxicity studies do not indicate that pre- and postnatal exposure results in increased sensitivity, EPA often reduces the FQPA SF to 1x. If there is 

indication of increased sensitivity, or the necessary data are lacking, SFs of 3X or 10X are sometimes used. These higher safety factors are considered in this analysis to 

denote higher risk to infants and children, and such cases are highlighted in bold font.

8 The 3 columns to the right of the gray bar pertain to the use of each herbicide on soybean only, other current uses are excluded from this analysis.

9 The soybean seed food tolerance established in the relevant numbered paragraph in 40 CFR 180.

10 The Monsanto-calculated theoretical maximum dietary exposure to the most highly-exposed U.S. population subgroup if 100% of all soybean were treated with that 

herbicide, and residues were at tolerance levels. This theoretical exposure does not occur in real life, but allows a consistent comparison for all alternate herbicides. 

The calculation is made using the same DEEM dietary exposure model that EPA routinely uses http://www.durango-software.com/software/deem.html.

11 The ratio of the prior column divided by the cPAD. It denotes the percentage of the safe exposure level that is attributed to soybean residues, as a soybean risk 

index. High numbers are less favorable. Any value above 100% requires further risk refinement to be deemed acceptable, such as that for paraquat. Values greater 

than 10-times that of dicamba are highlighted in bold font.

12 Dicamba diglycolamine data are for Clarity (U.S. EPA Reg. No. 7969-137) and M1691 formulations (U.S. EPA Reg. No. 524-582).
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A.3.7.2.2. Ecological Effects of Alternative Herbicide Products – Non-target Species

Fish and Aquatic Invertebrates

Table A-27 provides information about the hazards, exposures, and risks of dicamba and each of the 

eighteen alternative herbicides to fish and aquatic invertebrates (considering 2,4-D acid, salts, and 

esters as one alternative herbicide). The listed parameters include:

 LC50 endpoints from acute fish toxicity studies, as reported in EPA’s ecotoxicity database76, 

published in a RED or in Registration Review risk assessments. The highest and lowest 

available LC50 values for any fish study are listed, regardless of species, including both fresh 

and marine species together. The purpose is to define a range of concentrations that spans 

the expected fish toxicity levels.

 EC50 endpoints from acute aquatic invertebrate studies, as reported from the same sources 

cited above. The highest and lowest available EC50 values for any invertebrate study are 

listed, regardless of species, including both fresh and marine species together. The purpose 

is to define a range of concentrations that spans the expected aquatic invertebrate-toxic 

levels.

 Estimated environmental exposure concentrations (EECs) in surface water for each of the 

eighteen alternative herbicides. The third column in Table A-27, identified as “Calculated 

EEC”, provides a simple standard estimate based on the maximum single application rate in 

soybean, using EPA’s standard field-farm pond scenario. This scenario examines a 1-acre 

pond in a 10-acre field in which (1) 5% of the application drifts into the 6-foot-deep pond 

and (2) 5% of the application onto the 10 acres runs off into the same pond. The fourth 

column in Table A-27 lists other model estimates of surface water concentrations as 

provided by one or more modeling programs, as cited by EPA in public documents, such as 

Federal Register final tolerance rule drinking water assessments. The purpose is to define a 

range of concentrations that spans available estimates of potential aquatic exposure levels.

 Calculated Risk Quotients (RQs) for aquatic animals, comprised of fish and aquatic 

invertebrates combined together. Rather than calculate a single RQ for each species, 

Monsanto has calculated a range of potential RQs for each herbicide, bracketed by the bestand worst-case values. The “best” RQ is derived from the ratio of the lowest reported EEC 

concentration divided by the highest LC50 or EC50 for any aquatic animal. Conversely, the 

“worst” RQ is derived from the ratio of the highest EEC concentration divided by the 

lowest LC50 or EC50 for any aquatic animal. (Note: the RQ figures are rounded to two 

decimal places, so that entries that appear as “0.00” mean that the specific RQ is less than 

0.005.) The purpose is to define a range of RQs that span and describe the risk posed by the 

alternative herbicide to aquatic animals. The RQs that exceed the EPA’s Level of Concern 

(LOC) of 0.5 are marked in bold font.

Using the worst-case risk quotient, ten of 18 alternative herbicides have risk quotients greater than 

or equal to 0.01, while the worst-case risk quotient for dicamba and seven other herbicides is <0.01. 

 

76 National Information System – Regional IPM Centers. OPP Pesticide Ecotoxicity Database. 

http://www.ipmcenters.org/Ecotox/index.cfm [Accessed May 27, 2010].
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Only three of these 10 herbicides have risk quotients greater than 0.05 or 0.1, the levels of concern 

for threatened or endangered species and acute restricted use, respectively. Two of these 10 

herbicides have RQ values greater than 0.5, the highest acceptable level of concern. Monsanto 

believes that based on risk quotients, dicamba offers a lower potential risk to aquatic animals relative 

to at least three of the 18 alternative herbicides: 2,4-D esters, flumioxazin, and lactofen. This 

conclusion is tabulated in Table A-24, which summarizes the comparative analysis of dicamba and 

alternative herbicides.

In order to approve a new use of a herbicide EPA must conclude that the herbicide, when used 

according to the label, does not pose an unreasonable adverse effect to humans or the environment. 

In addition, in order to establish a tolerance for the use of a herbicide on a food or feed crop, EPA 

must find that there is a reasonable certainty of no harm to human health from non-occupational 

(food, water and residential/recreational) exposures to the herbicide. Therefore, all alternative 

herbicides used in soybean production, including those discussed above, can be used safely and do 

not pose an unreasonable risk to humans or the environment. Nonetheless, in some instances, such 

as those mentioned above, dicamba offers a reduction in risk potential (i.e., hazard) compared to 

some alternative herbicides in the same risk category (e.g., aquatic animal risk). In other instances 

dicamba presents a similar risk potential compared to some alternatives. In a few cases, dicamba 

presents a greater risk potential compared to some alternatives. This comparative analysis serves to 

demonstrate that the use of dicamba on DT soybean is unlikely to result in a significant impact/risk 

to human health or the environment compared to current herbicide agronomic practices and in 

some instances its use may impart additional benefits as described above.
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Table A-27. Aquatic Toxicity Parameters for Fish and Aquatic Invertebrates for Alternative Herbicides

Active Ingredient

Maximum 

Soybean 

lb/acre 

(single 

treatment)1

Calculated 

EEC (ppm)

2,3

FIRST, GENEEC 

or PRZX/EXAMS 

Surface Water ppm 

(RED or Tolerance 

Rule)4

Fish LC50 Range 

(ppm)5

Aquatic 

Invertebrate LC50 or 

EC50 Range (ppm)f

Risk Quotient for 

Aquatic Animals 

Range6 Label Warnings7

low high low high best worst

glyphosate salts 1.5 0.050 0.0008 - 0.021 45 >1000 55 780 0.00 0.00

dicamba /DGA salt 1 0.034 0.01 - 0.036 28 > 270 >100 >270 0.00 0.00

2,4-D acid + salts 0.93 0.031 0.064 - 0.118 >80 2244 25 820 0.00 0.00

2,4-D esters 0.93 0.031 0.064 - 0.118 >0.15 14.5 2.2 12 0.00 < 0.79

flumioxazin 0.096 0.003 0.018 - 0.034 2.3 21 0.23 5.5 0.00 0.15 "toxic to invertebrates”

imazethapyr 0.064 0.002 0.006 > 112 423 > 109 > 1000 0.00 0.00

cloransulam-methyl 0.04 0.001 0.002 > 86 > 154 > 111 > 121 0.00 0.00 "toxic to invertebrates”

chlorimuron-ethyl 0.14 0.005 0.003 - 0.005 > 2 8.4 >10a > 10 0.00 0.00

fomesafen 0.375 0.013 0.006 - 0.012 126 > 163 25 376 0.00 0.00

flumiclorac-pentyl 0.081 0.003 0.00024 >0.189 > 24 >0.189 >38 0.00 0.02 "toxic to shrimp"

sulfentrazone 0.31 0.010 0.004 - 0.016 94 > 120 1 60.4 0.00 0.02 "toxic to invertebrates”

thifensulfuron 0.013 0.000 0.0003 - 0.004 >100 > 100 >1000 > 1000 0.00 0.00
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Table A-27 (continued). Aquatic Toxicity Parameters for Fish and Aquatic Invertebrates for Alternative Herbicides

Active Ingredient

Maximum 

Soybean 

lb/acre 

(single 

treatment)1

Calculated 

EEC (ppm)

2,3

FIRST, GENEEC 

or PRZX/EXAMS 

Surface Water ppm 

(RED or Tolerance 

Rule)4

Fish LC50 Range 

(ppm)5

Aquatic 

Invertebrate LC50 or 

EC50 Range (ppm)5

Risk Quotient for 

Aquatic Animals 

Range6 Label Warnings7

low high low high best worst

imazaquin 0.123 0.004 0.004 - 0.008 280 420 280a 280 0.00 0.00

imazamox-ammonium 0.04 0.001 0.002 > 94.2 > 122 >94.3 > 122 0.00 0.00

paraquat dichloride 1.0 0.033 0.0015 > 1 156 1.2 1.2 0.00 < 0.05

lactofen 0.3 0.011 0.000008 - 0.4 0.46 0.46 0.02 4.85 0.00 20 "toxic to fish"

glufosinate-ammonium 0.66 0.022 0.043 - 0.094 > 320 > 1000 8 668 0.00 0.01

2,4-DB 0.4 0.013 0.013 - 0.015 2 18 25a 25 0.00 0.01 "toxic to fish"

fluthiacet-methyl 0.0065 0.000 0.0005 - 0.0008 0.043 0.16 0.3 >2.3 0.00 0.02

acifluorfen sodium 0.374 0.013 0.0024 - 0.010 31 204 28.1 > 1000 0.00 0.00

mesotrione 0.1875 0.011 0.004 - 0.02 > 114 520 3.3 840 0.00 0.01

1The highest single-treatment rate permitted by the herbicide’s product labels. This rate is used to calculate potential acute exposure to aquatic non-target species via 

spray drift or runoff.

2Based on the maximum single treatment rate, with 5% spray drift and 5% runoff from 10 treated acres into a 1-acre 6-foot-deep pond.

3The Estimated Environmental Concentration in surface water. It was calculated by Monsanto using the EPA’s “standard field-farm pond scenario” 

http://www.epa.gov/oppefed1/models/water/geneec2_description.htm. In this scenario, it is assumed that the herbicide is applied to a 10 acre farm field containing 

a 1 acre pond that is six feet deep. The pond experiences 5% of the application rate by spray drift and 5% of the application on the soil enters the pond via runoff. 

This concentration estimation is a simple, conservative Tier 1 procedure that utilizes only the application rate to estimate aquatic exposures, and allows quick 

comparison of many different herbicides. Other more increasingly-detailed computer models can be used to obtain more refined EEC estimates, but these require the 

user to input various physical chemical parameters and weather data for each product to be modeled. Examples of these methods are listed in the next column.

4Modeling estimates of potential aquatic exposure levels. When EPA conducts risk assessments, it uses computer models to obtain estimates of potential surface water 

concentrations. These are published in the RED for each herbicide, or in tolerance rules in the Federal Register. The range of estimates is listed, which can be 

compared to the single number in the prior column. Sources of these estimates are listed in the “ALTERNATIVE HERBICIDE-SPECIFIC REFERENCES” 

section.

5“Fish LC50 Range (ppm)” and “Aquatic Invertebrate LC50 or EC50 Range (ppm)”. These four columns describe the range of hazard data found in public data sources 

representing the toxicity of each herbicide versus freshwater and marine animals. The LC50 or EC50 means the water concentration needed to kill or immobilize half of 

the test species, which is a standard potency descriptor. The highest and lowest values found for any fish species (trout, bluegill, sheepshead, etc.) were tabulated. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 421 of 946

Likewise, the highest and lowest values found for any aquatic invertebrate species (Daphnia, shrimp, crab, etc.) were included. Sources of these data are listed in the 

“ALTERNATIVE HERBICIDE-SPECIFIC REFERENCES” section and in available public databases (National Information System – Regional IPM Centers. OPP 

Pesticide Ecotoxicity Database. http://www.ipmcenters.org/Ecotox/index.cfm).

6EPA’s EFED uses a Risk Quotient (RQ) method for ecological risk assessment. The RQ equals the potential exposure level divided by the hazard level. Higher 

exposures or more potent hazard findings lead to higher RQs. EFED has established Levels of Concern (LOCs) for various non-target species categories. When the 

RQ exceeds the LOC, further refinement is needed to determine whether risk mitigation might be needed. For non-listed aquatic animals, the LOC for acute risk is 

0.5, for acute risk restricted use is 0.1, and for threatened or endangered species it is 0.05. In this analysis, Monsanto calculated best-case RQs by dividing the lowest 

EEC estimate by the highest hazard (LC50 or EC50) value, and calculated the worst-case RQ from the highest EEC and lowest hazard value. The purpose was to 

bracket a range that typified the aquatic animal risk presented by each herbicide. When neither the worst-case nor the best-case RQs exceed a LOC of 0.05, Monsanto 

concluded that risk to aquatic animals is minimal. Instances where the LOC threshold of 0.5 is exceeded are highlighted in bold font.

7Lists instances where the product label includes warning statements about aquatic animal exposure.
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Aquatic Plants 

Table A-28 provides information about the hazards, exposures, and risks of dicamba and each of the 

eighteen (18) alternative herbicides to aquatic plant species, specifically duckweed and aquatic algae 

species (considering 2,4-D acid, salts, and esters as one alternative herbicide). The data format, 

sources, and methods of Estimated Environmental Exposure Concentration (EEC) calculation are 

identical to those described above for the aquatic animals (Table A-27). A Level of Concern (LOC) 

value of 1.0 has been used for judging RQ exceedances in the case of aquatic plants, consistent with 

EPA EFED’s normal practices.

The assessment and comparison summarized in Table A-28 establishes that dicamba poses little 

acute risk to aquatic plants at use rates of 0.05 – 1.0 lb dicamba a.e./acre, which is consistent with 

EFED’s assessment published in the RED EFED Chapter. Monsanto was unable to identify 

aquatic plant hazard data for three of the alternative herbicides (imazaquin, chlorimuron-ethyl, and 

flumiclorac-pentyl). For nine (9) of the eighteen (18) alternative herbicides, the range of RQs is 

< 0.005 to 0.75; that is, none of these nine a.i.’s present an aquatic plant risk, which even in the 

worst-case calculation, reach EFED’s Level of Concern (LOC) for aquatic plants. However, for 

seven of the alternative herbicides, the worst-case RQs did exceed EFED’s LOC of 1.0. It is not 

surprising that some herbicides are quite toxic to aquatic plants, and the worst-case RQs for three of 

the alternate herbicides (flumioxazin, lactofen, and paraquat dichloride) exceeded the LOC by a 

factor of more than 50-fold.

Monsanto believes that dicamba offers a lower potential risk to aquatic plants relative to at least 

seven of the 18 alternative herbicides (2,4-D, flumioxazin, sulfentrazone, thifenslufuron, paraquat 

dichloride, lactofen, and mesotrione).77 This conclusion is tabulated in Table A-24, which 

summarizes the comparative analysis of dicamba and alternative herbicides.

 

77 As discussed in section A.3.7.2.2, all alternative herbicides used in soybean production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category. 
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Table A-28. Aquatic Toxicity Parameters for Aquatic Plants for Alternate Herbicide Active Ingredients

Active Ingredient

Maximum 

Soybean 

lb/acre 

(single 

treatment)1

Calculated 

EEC 

(ppm) 2,3

FIRST, 

GENEEC or 

PRZX/EXAMS 

Surface Water 

ppm (RED or 

Tolerance Rule)4

Duckweed and 

Algae EC50 Range 

(ppm)5

Risk Quotient for 

Aquatic Plants 

Range6

low high best worst

glyphosate salts 1.5 0.050 0.0008 - 0.021 0.77 38.6 0.00 0.06

dicamba /DGA salt 1 0.034 0.01 - 0.036 0.06 > 3.7 0.00 0.60

2,4-D acid + salts 0.93 0.031 0.064 - 0.118 0.29 156 0.00 0.41

2,4-D esters 0.93 0.031 0.064 - 0.118 0.066 >19.8 0.00 1.79

flumioxazin 0.096 0.003 0.018 - 0.034 0.0005 0.019 0.16 68.00

imazethapyr 0.064 * 0.002 0.006 0.008 59.2 0.00 0.75

cloransulam-methyl 0.04 0.001 0.002 0.003 135 0.00 0.67

chlorimuron-ethyl 0.14 0.005 0.003 - 0.005 NA NA NA NA

fomesafen 0.375 0.013 0.006 - 0.012 0.09 71 0.00 0.14

flumiclorac-pentyl 0.081 0.003 0.00024 NA NA NA NA

sulfentrazone 0.31 0.010 0.004 - 0.016 0.002 0.033 0.12 8.0

thifensulfuron 0.013 0.000 0.0003 - 0.004 0.0016 > 0.026 0.02 2.50

imazaquin 0.123 0.004 0.004 - 0.008 NA NA NA NA

imazamox-ammonium 0.04 0.001 0.002 0.011 > 0.038 0.03 0.18

paraquat dichloride 1.0 0.033 0.0015 0.00055 2.84 0.00 90.9

lactofen 0.3 0.011 0.000008 - 0.4 0.001 0.001 0.00 400

glufosinate-ammonium 0.66 0.022 0.043 - 0.094 1.5 7.8 0.00 0.06

2,4-DB 0.4 0.013 0.013 - 0.015 >0.932 >0.932 <0.01 <0.02

fluthiacet-methyl 0.0065 0.000 0.0005 - 0.0008 0.0022 >0.018 <0.01 0.36

acifluorfen sodium 0.374 0.013 0.0024 - 0.010 > 0.26 0.38 0.01 <0.05

mesotrione 0.1875 0.011 0.004 - 0.02 0.018 132 0.00 1.11

The first three columns in this table are identical to- those in Table A-21.
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1The highest single-treatment rate permitted by the herbicide’s product labels. This rate is used to calculate potential acute exposure to aquatic non-target species via spray 

drift or runoff.

2Based on the maximum single treatment rate, with 5% spray drift and 5% runoff from 10 treated acres into a 1-acre 6-foot-deep pond.

3The Estimated Environmental Concentration in surface water. It was calculated by Monsanto using the EPA’s “standard field-farm pond scenario” 

http://www.epa.gov/oppefed1/models/water/geneec2_description.htm |Accessed May 28, 2010|. In this scenario, it is assumed that the herbicide is applied to a 10 

acre farm field containing a 1 acre pond that is six feet deep. The pond experiences 5% of the application rate by spray drift and 5% of the application on the soil enters 

the pond via runoff. This concentration estimation is a simple, conservative Tier 1 procedure that utilizes only the application rate to estimate aquatic exposures, and 

allows quick comparison of many different herbicides. Other more increasingly-detailed computer models can be used to obtain more refined EEC estimates, but these 

require the user to input various physical chemical parameters and weather data for each product to be modeled. Examples of these methods are listed in the next column.

4Modeling estimates of potential aquatic exposure levels. When EPA conducts risk assessments, it uses a computer models to obtain estimates of potential surface water 

concentrations. These are published in the RED for each herbicide, or in tolerance rules in the Federal Register. The range of estimates is listed, which can be compared 

to the single number in the prior column. Sources of these estimates are listed in the “ALTERNATIVE HERBICIDE-SPECIFIC REFERENCES” section.

5These two columns describe the range of hazard data found in public data sources representing the toxicity of each a.i. versus freshwater and marine plants. The EC50

means the water concentration needed to kill or prevent growth of half of the test species, which is a standard potency descriptor. The highest and lowest values found 

for any aquatic plant species (diatom, duckweed, alga, etc.) were tabulated. Sources of these data are listed in the “ALTERNATIVE HERBICIDE-SPECIFIC 

REFERENCES” section of this document and in available public databases cited in National Information System – Regional IPM Centers. OPP Pesticide Ecotoxicity 

Database. http://www.ipmcenters.org/Ecotox/index.cfm

6As described above for Table A-27, EPA’s EFED uses a Risk Quotient (RQ) method for ecological risk assessment. For non-listed aquatic plants or for threatened or 

endangered species the LOC is 1.0. In this analysis, Monsanto calculated best-case RQs by dividing the lowest EEC estimate by the highest hazard (EC50) value, and 

calculated the worst-case RQ from the highest EEC and lowest hazard value. The purpose was to bracket a range that typified the aquatic plant risk presented by each 

herbicide. When neither the worst-case nor the best-case RQs exceed a LOC of 1.0, Monsanto concluded that risk to aquatic plants is minimal. Instances where the LOC 

threshold of 1.0 is exceeded are highlighted in bold font.
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A.3.7.2.3. Looking Toward the Foreseeable Future

Weeds that are difficult to control with glyphosate and weeds that are glyphosate-resistant, PPOresistant, or ALS-resistant represent an opportunity for improved weed control in soybean. To 

address this need, Monsanto is seeking to commercialize DT soybean, which will allow dicamba to 

be used as a weed control tool in this important U.S. crop. Monsanto is also aware that other 

companies are developing biotechnology-derived soybean enhanced with other herbicide-tolerant 

traits. 

Biotechnology-derived soybean developed to be tolerant to applications of 2,4-D has been 

submitted to USDA-APHIS for deregulation.78 Monsanto believes that the data show that 2,4-D 

presents more relative risk than dicamba in the area of acute human health and chronic exposure 

risk, and, for 2,4-DB, relatively more ecological risk for aquatic animals. Applications of 2,4-D will 

also require management of offsite movement. 

In addition, biotechnology-derived soybean enhanced to be tolerant to herbicides that inhibit 4-

hydroxyphenylpyruvate dioxygenase (HPPD) has also been submitted to USDA-APHIS for 

deregulation,79 and EPA recently approved mesotrione for use on mesotrione-tolerant soybean (U.S. 

EPA, 2009e). HPPD-tolerance allows use of these broadleaf herbicides in soybean production, 

which is a good technical fit as highlighted by Table A-29 which shows many of the troublesome 

soybean weeds are effectively controlled by HPPD herbicide products such as Balance Pro (active 

ingredient: isoxaflutole), Laudis (active ingredient: tembotrione) or Callisto Herbicide (active 

ingredient: mesotrione). Since some of these products are not yet registered for soybean use, and 

the label for Callisto defining application parameters in soybean is not yet commercially available, it 

is not possible to undertake a rigorous application-rate-based risk comparison with dicamba; 

however, it is possible to make a hazard comparison, using isoxaflutole and tembotrione as typical 

examples. (Mesotrione is included above in the discussion of alternate herbicides, since has been 

approved by EPA). 

Inhibition of HPPD in plants results in a disruption of carotenoid biosynthesis, which leaves the 

plant’s chlorophyll pigments unprotected from rapid degradation via photooxidation, and results in a 

very characteristic white bleached symptomology of plant parts that are normally green. HPPD is 

also an animal liver enzyme involved in the catabolic breakdown of tyrosine, and its inhibition in 

laboratory animals results in elevated tyrosine plasma concentrations (tyrosinemia), which can cause 

adverse ocular, developmental, liver, and kidney effects. Stated simply, the mechanism of herbicidal 

efficacy based on HPPD inhibition is inherently linked to a potential for negative human health 

effects. 

Publicly available study results show that isoxaflutole and tembotrione both caused ocular and liver 

effects in test animals, and both caused developmental toxicity at non-maternally toxic levels. 

Because of the potent toxic effects, EPA has calculated cPADs for isoxaflutole and tembotrione that 

are lower than that of dicamba by factors of 225 and 1125, respectively. EPA is also considering the 

 

78 Dow Agrosciences press release, December 15, 2009. 

http://www.dowagro.com/newsroom/corporatenews/2009/20091215a.htm.

79 See http://www.aphis.usda.gov/biotechnology/petitions_table_pending.shtml.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 426 of 946

need for a cumulative risk assessment approach for these two chemicals, along with mesotrione and 

other HPPD-inhibiting herbicides, because they share a common toxic mechanism (U.S. EPA, 

2009d,e). In addition, both isoxaflutole and tembotrione had carcinogenic effects in long-term 

testing summarized by EPA. For tembotrione, carcinogenicity was limited to rats only, but 

isoxaflutole was found to have carcinogenic effects in two species, and was categorized by EPA as a 

B2 carcinogen in 1998 when first registered. Isoxaflutole products, such as Balance Pro, are 

Restricted Use pesticides because of a very high level of concern about damage to non-target plants 

caused by spray drift, and isoxaflutole labels also bear warning statements about the likelihood of 

persistence and leaching. There have also been concerns about isoxaflutole use leading to levels of 

herbicidally-active isoxaflutole metabolites in surface water utilized for irrigation purposes. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 427 of 946

A.3.7.2.4. Efficacy and Weed Management Practices of Alternative Herbicide Products

Table A-29 provides weed control effectiveness of formulated products containing dicamba, 

glyphosate and alternate herbicides. Weed control less than 70% is considered insufficient (white), 

control between 70 and 85% is considered as marginal effectiveness (black-white), and control of 

more than 85% is considered commercially acceptable (black). The data presented in Table A-29 are 

derived by combining state and dealer80 herbicide guidance for soybean production across major 

soybean-producing states (Ohio and Indiana81, Iowa

82, Tennessee83, North Dakota84). Weed control 

herbicide recommendations provided by University Extension scientists to control specific weeds 

were converted to a common scale and combined to reflect an average herbicide weed control rating 

across geographies. Weed control ratings specific to resistant weeds were based mainly on 

recommendations from Ohio and Indiana. Monsanto weed scientists applied their own expert 

scientific judgment during the conversion of University Extension recommendations into a common 

scale. The weeds chosen for inclusion in Table A-29 represent current problem weeds in soybean, 

either because they exhibit herbicide resistance or because they are generally hard-to-control species. 

(See Appendix B of this Environmental Report for more information on the most common 

herbicide-resistant weeds in soybean systems.)

As Table A-29 shows, the alternative herbicides can be used in preemergent applications, 

postemergent applications, or, like dicamba and glyphosate, as both pre- and postemergent 

applications. Several herbicides, such as 2,4-D, 2,4-DB, sulfentrazone and paraquat, do not have 

sufficient soybean safety for application in-crop, so their use is limited to control of existing weeds 

and preemergent control of later emerging weeds via soil residual activity, if any. Others, such as the 

protoporphyrinogen oxidase (PPO) inhibitors acifluorofen, lactofen, and fomesafen, are most 

effective as postemergent treatments, even though they may cause some soybean leaf injury. 

Acetolactate synthase (ALS) inhibitors like chlorimuron-ethyl and cloransulam-methyl can be used at 

either timing. Glufosinate, like glyphosate and dicamba, does not have intrinsic soybean selectivity 

and can only be used as a postemergent application over soybean that is genetically enhanced to 

provide glufosinate tolerance (e.g., Liberty Link®).

Table A-29 also highlights expected weed efficacy trends. Glyphosate does not provide commercial 

control of glyphosate-resistant weed biotypes such as common ragweed or horseweed, but does 

control the wild type plants of these species. Similarly, ALS-inhibiting herbicides provide poor 

control of ALS-resistant weeds, and PPO inhibitors do not adequately control PPO-resistant weeds. 

Table A-29 focuses on problem weeds found in soybean and does not include any weeds with auxin 

resistance, although 2,4-D provides good control of many herbicide-resistant broadleaf weed 

biotypes in this group. Extreme®, which contains two modes-of-action (glyphosate and 

 

80 2009 Crop Protection Guide - Information for Dealers http://www.agrisolutionsinfo.com/ Accessed May 28, 2010

81 2010 Ohio and Indiana Weed Control Guide (Bulletin 789; Pub. WS16) www.btny.purdue.edu/Pubs/WS/WS-16/ Accessed May 

28, 2010

82 2009 Herbicide Guide for Corn and Soybean Production - http://www.weeds.iastate.edu [Accessed May 28, 2010]

83

 2010 Weed Control Manual for Tennessee http://www.utextension.utk.edu/publications/pbfiles/pb1580.pdf Accessed may 28, 

2010

84 2010(a) NDSU Weed Control Guide - http://www.ndsu.edu/weeds Accessed May 28, 2010
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 428 of 946

imazethapyr), provides better control of this target weed spectrum than most of the herbicide 

products having only a single mode-of-action.
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Table A-29. Herbicide Efficacy Comparison: Herbicide Resistant Weeds and Hard-to-Control Weeds in Soybean

2 >85% control

1 70% - 85% control

0 < 70% control

Herbicide Herbicide Brand

Class GR Waterhemp GR Palmer amaranth GR Horseweed GR C. ragweed GR G. ragweed GR Johnsongrass ALS C. ragweed ALS+PPO C. ragweed ALS+GR C. ragweed ALS G. ragweed ALS+GR G. ragweed ALS+GR Horseweed ALS Kochia TRI Lambsquarters A. Morningglory B. Nightshade Cockelbur C. Ragweed G. Ragweed Hemp sesbania Kochia Lambsquarters Horseweed Palmer Amaranth Prickly Sida Sicklepod Velvetleaf Waterhemp

Glyphosate Roundup EPSPS

Dicamba Clarity auxin

2,4-D 2,4-D auxin

2,4 DB Butyrac 200 auxin

Chlorimuron + Metribuzin Canopy DF ALS/PSII

Chlorimuron + Tribenuron Canopy EX ALS

Imazaquin Scepter ALS

Sulfentrazone + Imazethapyr Authority Assist PPO/ALS

Sulfentrazone + Metribuzin Authority MTZ PPO/PSII

Sulfentrazone + Cloransulam Authority First / Sonic PPO/ALS

Flumioxazin Valor PPO

Flumioxazin + Chlorimuron Valor XLT PPO/ALS

Flumioxazin + Cloransulam Gangster PPO/ALS

Cloransulam Firstrate ALS

Paraquat Gramoxone Inteon PSI

Isoxaflutole Balance PRO HPPD

Mesotrione Callisto HPPD

Mesotrione Callisto HPPD

Tembotrione Laudis HPPD

Tropramezone Impact HPPD

Hard-to-Control Weeds2

HPPD POSTEMERGENCE5

Resistant Weeds1

PREEMERGENCE/BURNDOWN3

HPPD PREEMERGENCE4
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Table A-29 (continued). Herbicide Efficacy Comparison: Herbicide Resistant Weeds and Hard-to-Control Weeds in Soybean

2 >85% control

1 75% - 85% control

0 < 75% control

Herbicide Herbicide Brand

Class GR Waterhemp GR Palmer amaranth GR Horseweed GR C. ragweed GR G. ragweed GR Johnsongrass ALS C. ragweed ALS+PPO C. ragweed ALS+GR C. ragweed ALS G. ragweed ALS+GR G. ragweed ALS+GR Horseweed ALS Kochia TRI Lambsquarters A. Morningglory B. Nightshade Cockelbur C. Ragweed G. Ragweed Hemp sesbania Kochia Lambsquarters Horseweed Palmer Amaranth Prickly Sida Sicklepod Velvetleaf Waterhemp

Glyphosate Roundup EPSPS

Dicamba Clarity auxin

Imazethapyr + Glyphosate Extreme ALS/EPSPS

Fomesafen Flexstar PPO

Imazethapyr Pursuit ALS

Cloransulam Firstrate ALS

Flumiclorac Resource PPO

Chlorimuron Classic ALS

Imazamox Raptor ALS

Lactofen Cobra / Phoenix PPO

Fomesafen Reflex PPO

Acifluorfen Ultra Blazer PPO

Glufosinate Ignite Glu

Chlorimuron + Thifensulfuron Synchrony XP ALS

Fluthiacet Cadet PPO

Hard-to-Control Weeds2 Resistant Weeds1

POSTEMERGENCE5

Horseweed is synonymous to marestail.

GR = Glyphosate resistant

ALS = Acetolactate synthase

Tri = Triazine
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 431 of 946

PPO = protoporphyrinogen oxidase

Note: This table was based primarily on State University Extension weed control recommendations for soybean growing areas, Table A-29 indicates the degree to 

which each product controls the targeted weeds in soybean. The legend describes the meaning of the symbols. 

1 This section of the table describes control of populations (biotypes) of weeds that are known to have genetic resistance to specific herbicidal modes-of-action

2 This section describes control of weeds that are difficult to control in soybean with existing herbicide treatments. Generally these are broadleaf weeds whose removal 

would require herbicide rates that would severely damage the crop.

3 This section describes weed control by herbicides that are applied prior to soybean emergence. The weeds may or may not be emerged.

4 This section describes foreseen use of herbicides that are not yet approved for use in soybean that have inhibition of 4-hydroxyphenylpyruvate dioxygenase.

5 The section describes weed control by herbicides that are applied after the soybean emergence, generally over-the-top of the crop.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 432 of 946

A.3.7.3. Comparison of Dicamba Use in the Dicamba-Tolerant Soybean System to 

Alternative Herbicides

The intent of the comparative analysis is to define current herbicide use in U.S. soybean production, 

and to compare dicamba’s human health and environmental properties to herbicides currently used 

by growers for weed control. In order to approve a new use of a herbicide EPA must conclude that 

the herbicide, when used according to the label, does not pose an unreasonable adverse effect to 

humans or the environment. In addition, in order to establish a tolerance for the use of a herbicide 

on a food or feed crop, EPA must find there is a reasonable certainty of no harm to human health 

from non-occupational (food, water and residential/recreational) exposures to the herbicide.

Consequently all alternative soybean herbicides can be used safely, and do not pose an unreasonable 

risk to humans or the environment. 

Nonetheless, in some instances, dicamba offers a reduction in risk potential (i.e., hazard) compared 

to some alternative herbicides in the same risk category (e.g., aquatic plant risk). In other instances 

dicamba presents a similar risk potential compared to some alternatives. In a few cases, dicamba 

presents a greater risk potential compared to some alternatives. This comparative analysis serves to 

demonstrate that the use of dicamba on DT soybean is unlikely to result in a significant impact/risk 

to human health or the environment compared to current herbicide agronomic practices and in 

some instances, its use may impart additional benefits as described below. 

A.3.7.3.1. Comparisons for Human Health Risks

Table A-26 provides information concerning human health parameters for dicamba and the 

alternative herbicide products. These data allow a comparison of the relative human health safety 

among the optional weed control products on the basis of:

 Acute toxicity.

 Chronic toxicity.

 Cancer risks and classification.

 Risk to infants and children.

 Magnitude of potential exposure that is considered to be within the acceptable safe range.

 Extent to which all presently approved uses exhaust the acceptable safe acute and chronic 

dietary exposure ranges for the most highly exposed population subgroups.

 The proportion of present dietary exposure that arises through use on soybean.

A compilation of Monsanto’s comparative determinations of the risks posed by the 18 alternate 

herbicides compared to dicamba in the four basic human health risk categories (acute, cancer, 

chronic and infants/children) is tabulated in Table A-30. A “Yes” entry indicates a benefit for 

dicamba compared to that alternative herbicide. Entries not indicated with a “Yes” mean that 

dicamba is either comparable to or less benign than the alternative herbicide. A “Neutral” entry 

means that dicamba and the alternative herbicide have similar risks, and a “No” entry denotes 

alternative herbicides that have a benefit compared to dicamba. Table A-30 is intended as a 1-page 

scorecard summary of these benefit comparisons. Monsanto has concluded that dicamba use on DT 

soybean will provide benefits compared to the alternate herbicides used for soybean weed control.
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Table A-30. Summary of Comparative Analysis of Dicamba and Alternative Herbicides Used in Soybean

Active 

Ingredient

Mode-ofAction 

(WSSA 

Group1)

Human Health Risk Measures2

Aquatic Non-Target 

Species Risk 

Measures3 Known 

Resistant 

Weed 

Species4

Herbicidal 

Efficacy5

(< 50% of 

dicamba)

Long 

Rotational 

Crop 

Restriction6

Serious 

Crop 

Injury 

Potential7

Number 

of “Yes” 

Entries8

Acute 

Toxicity 

Risk

Cancer 

Risk

Chronic 

Risk

Infants & 

Children 

Risk

Aquatic 

Animal 

Risk

Aquatic 

Plant 

Risk

Number 

of “No” 

Entries9

2,4-D acid / 

esters Aux (4)

Yes Yes Yes Neutral Yes Yes

28

Neutral Neutral Neutral 6 0

2,4-DB Neutral Neutral Neutral Neutral Neutral Neutral Yes Neutral Neutral 2 0

imazethapyr ALS (2) No Neutral Neutral Neutral Neutral Neutral

107 (Yes)

Yes Yes Neutral 3 1

cloransulammethyl ALS (2) No Neutral Neutral Neutral Neutral Neutral Yes Yes Neutral 4 1

chlorimuronethyl

ALS (2) No Neutral Neutral Neutral Neutral NA Yes Yes Neutral 3 1

thifensulfuron ALS (2) No Neutral Neutral Neutral Neutral Yes Yes Yes Neutral 4 1

imazaquin ALS (2) No No Neutral Neutral Neutral NA Yes Yes Neutral 3 2

imazamoxammonium

ALS (2) No Neutral No Neutral Neutral Neutral Yes Yes Neutral 4 2

flumioxazin PPO (14) Neutral Neutral Yes Neutral Yes Yes Yes Yes Neutral 5 0

fomesafen PPO (14) Yes Neutral Yes Neutral Neutral Neutral Neutral Yes Yes 4 0

flumicloracpentyl PPO (14)No No Neutral Neutral Neutral NA Yes Neutral Neutral 1 2

sulfentrazone PPO (14) Yes Neutral Neutral Neutral Neutral Yes 5 Yes Neutral Neutral 4 0

lactofen PPO (14) No Yes Neutral Yes Yes Yes Neutral Neutral Yes 5 1

fluthiacetmethyl

PPO (14) No Yes Neutral Neutral Neutral Neutral Yes Neutral Yes 3

1

acifluorfen 

sodium PPO (14) Yes Yes Neutral Yes Neutral Neutral Yes Neutral Yes 5

0

paraquat 

dichloride BiPyr (22)

Yes No Yes Neutral Neutral Yes 24 Yes Neutral Neutral 4 0

glufosinateammonium Glu (10)Yes No Yes Neutral Neutral Neutral No reports Neutral Neutral Neutral 3 0

mesotrione HPPD (28) No Neutral Neutral Yes Neutral Yes No reports Yes Yes Neutral 4 1
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 434 of 946

Table A-30 is intended to be a 1-page scorecard to track the benefits of dicamba use on DT soybean according to the different listed criteria. Each “Yes” entry signifies 

that Monsanto has concluded that dicamba represents a benefit versus the relevant alternative herbicide on the basis of the risk factor in that column’s heading. The basis 

for entering a “Yes” under each risk factor is further explained in the relevant portions of this document. ”Neutral” entries indicate similar risks exist for dicamba and the 

alternative herbicide. “No” means the alternative herbicide offers a risk benefit compared to dicamba.

1The herbicidal biochemical mechanism of weed-killing activity, according to the Weed Science Society of America.

www.plantprotection.org/HRAC/Bindex.cfm?doc=MOA.html

2A tally of the benefits dicamba use on DT soybean offers over the alternative herbicide in the four categories of human health risk.

3A tally of the benefits dicamba use on DT soybean offers over the alternative herbicides in the two categories of aquatic non-target species risk.

4A listing of the worldwide numbers of known resistant weeds for each herbicide based on its mode-of-action group. Dicamba has 5 known resistant spp worldwide. A 

“Yes” indicates that the number of resistant weeds in this herbicide class is many more than the known five dicamba resistant species biotypes. A comparison of each 

individual herbicide in the class is not provided. www.weedscience.org/summary/MOASummary.asp

5Alternative herbicides that provide commercial control of fewer than 50% of targeted problem weeds in soybean compared to dicamba, according to the data in Table A23, where commercial control is considered to be >85%, as indicated by a fully-black circle symbol. 

6 Alternative herbicides that require long waiting periods between application and subsequent planting of a crop other than soybean. This constraint is a disadvantage to 

growers. See Table A-31.

7Alternative herbicides that can substantially injure the soybean crop when applied for weed control, potentially reducing soybean yield. 

8 Tabulation of the number of “Yes” entries in each row, indicating a total score for improved risk profile for dicamba use on DT soybean offers versus an alternative 

herbicide. This summation is not presented as a net value (i.e., subtracting where an alternative herbicide has a benefit over dicamba).

9 Tabulation of the number of “No” entries in each row, indicating a total score for worse risk profile for dicamba use on DT soybean offers versus an alternative 

herbicide. This summation is not presented as a net value (i.e., subtracting where an alternative herbicide has a benefit over dicamba).

NA – not available.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 435 of 946

Acute Health Risks

Dicamba acid has a Category II classification for eye and skin irritation, but once the acid is 

neutralized to form the DGA or other salt forms used in herbicide product formulations, all acute 

Categories are III or IV. These classifications are the most benign acute toxicity categories in EPA’s 

acute hazard paradigm. Several alternative herbicides (acifluorfen, sulfentrazone, and some forms of 

2,4-D) have high risk of eye irritation (Category I). Principal formulations of fomesafen, paraquat, 

lactofen, 2,4-DB (DMA salt), and acifluorfen have a “DANGER!” signal word (Table A-31). The 

18 alternate herbicide actives, as a group, also have relatively low acute (oral, dermal or inhalation) 

toxicity. For eight of the eighteen, EPA determined that an acute dietary risk assessment is not 

needed because there are no relevant acute toxicological effects. One notable exception is paraquat, 

which has high risk (Category I) of acute toxicity by the inhalation route; present uses of paraquat 

occupy 66% of the aPAD (the safe exposure level). 2,4-D and glufosinate have relatively low 

aPADs compared to their dietary residues, and present uses occupy 58% and 48% of their respective 

aPADs. Overall, Monsanto concludes that dicamba has a lower acute toxicity risk potential 

compared to six of the eighteen alternate herbicides and their formulated products (paraquat, 2,4-D, 

glufosinate, acifluorfen, sulfentrazone, and fomesafen).

85

 These six are indicated by a “Yes” in the 

“Acute Toxicity Risk” column of Table A-30. Flumioxazin and 2,4-DB were judged to have similar 

acute toxicity risk as dicamba, and are marked as “Neutral” in Table A-30. Ten herbicides, which 

either did not have relevant acute toxicological effects or which utilized 1% or less of the allowable 

acute exposure (aPAD), were judged to have less acute toxicity risk than dicamba, and are marked as 

“No” in Table A-30.

Chronic Risk

Chronic dietary risk can be evaluated by consideration and comparison of the percentage of the safe 

exposure level (chronic population adjusted dose: cPAD) that is used up by all currently registered 

uses of an active ingredient. Table A-30 summarizes the % cPAD utilized for each alternative

herbicide, according to recently published Federal Register Final Rule information. A number of the 

alternative herbicides have very low use rates, which results in very low residues in treated food or 

feed, and accordingly utilize only a small percentage of the cPAD. For dicamba and twelve of the 

alternate herbicides, the percentage of the cPAD utilized for all approved uses is <10%, so that this 

group has at least an added 10-fold margin of safety beyond that which EPA has determined is 

protective of human health. For imazamox, EPA has determined that residues in food or feed are 

not likely to approach levels of concern, and exempted it from the requirement of food and feed 

tolerances. The remaining five herbicides (2,4-D, flumioxazin, fomesafen, paraquat, and glufosinate) 

utilize a somewhat higher portion of the cPAD, ranging from 18% to 38%. Although the 10% 

cutoff is an arbitrary one, and the increased risk of even the worst-case alternative herbicide for 

chronic risk is only 6-fold greater than that of dicamba, Monsanto concludes that dicamba offers a 

lower chronic toxicity risk potential compared to 2,4-D, flumioxazin, fomesafen, paraquat and 

glufosinate.

 

85 As discussed in section A.3.7.2.2, all alternative herbicides used in soybean production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 436 of 946

Another way to compare chronic dietary risk would be to focus directly on the soybean seed 

residues and their contribution to cPAD utilization. In Table A-26, columns 9 to 11 (those to the 

right of the gray bar) present the established soybean seed tolerance for each herbicide. Using 

DEEM (a computer dietary exposure model used commonly by EPA) and a theoretical worst-case 

approach (assume 100% of soybean is treated with a given herbicide that results in residues at the 

tolerance level), Monsanto calculated the theoretical maximum residue contribution (TMRC, a 

standard Tier 1 dietary risk method) to dietary exposure of each herbicide via soybean seed in 

μg/kg/day and as a percentage of the cPAD, as shown in Table A-26. This analysis highlighted 

paraquat and glufosinate as alternative herbicides with notably higher cPAD utilization by the 

soybean residue component; both herbicides were considered to present more relative risk than 

dicamba in the previous comparative method as well. The TMRC soybean calculation for paraquat 

yields a number that is 2.6-fold higher than the cPAD, because the EPA’s risk assessment 

methodology for paraquat assumes a market penetration in soybean of <5%. If this market share 

were increased, the risk attributed to soybean residue could become a substantial portion of the 

cPAD.

Based on this reasoning, Monsanto concluded that dicamba offers lower chronic toxicity risk 

potential than five alternative herbicides (2,4-D, flumioxazin, fomesafen, paraquat and glufosinate), 

and these a.i.’s are marked with a “Yes” in the chronic toxicity column of Table A-30.85 Imazamoxammonium was considered by EPA to have such low toxicity that no food or feed tolerances were 

required by EPA, and therefore imazamox-ammonium was judged by Monsanto to have lower 

chronic toxicity risk potential than dicamba, as indicated by a “No” in Table A-24. The other 

alternative herbicide a.i.’s under consideration were judged to have similar chronic toxicity risk as 

dicamba, and are marked “Neutral” in Table A-30.

Cancer Risk

EPA classified dicamba as “not likely” for human carcinogenicity. Fourteen of the alternative 

herbicides are classified similarly – “not likely”, “no evidence”, or “Group E (Evidence of NonCarcinogenicity for Humans)”. 2,4-D is classified as “D”, meaning that although the studies are 

acceptable, the evidence is unclear and some uncertainty remains. Two of the alternative herbicides 

(lactofen and acifluorfen) are classified as “not likely” at low doses but “likely” at high doses, due to 

liver and other effects. A peroxisome proliferation mechanism is established for acifluorfen. Since 

acifluorfen is a metabolite of lactofen, the similarity in toxicology and cancer classification is 

appropriate. One alternative herbicide, fluthiacet-methyl, is categorized as a “likely” human 

carcinogen, due the occurrence of dose-related tumors in both rats and mice; a Q* of 7.5 X 10-7has 

been calculated, which is a measure of carcinogenic potency that EPA utilizes in risk assessment. 

Overall, Monsanto concludes that dicamba offers a lower cancer risk potential compared to four of 

the alternative herbicides (2,4-D, lactofen, acifluorfen, and fluthiacet-methyl), and this judgment is 

indicated by a “Yes” in the Cancer Risk column of Table A-30. Four alternative herbicide a.i.’s 

(flumiclorac-pentyl, glufosinate, imazaquin, and paraquat) have been categorized by EPA as Group 

E or “no evidence”, and Monsanto judges that these four have lower cancer risk potential than 

dicamba, and are marked as “No” in Table A-30. The other alternative herbicide a.i.’s that are in the 

“not likely” category have similar cancer risk potential to dicamba, and are marked as “Neutral” in 

table A-30.85
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 437 of 946

Risks to Infants and Children

The Food Quality Protection Act (FQPA) requires that EPA take special care in its risk assessments 

to establish that infants and children do not have increased sensitivity to pesticides and thereby 

experience greater risks from residues in food than the general U.S. population. EPA’s 

implementation of this requirement is embodied in the additional FQPA safety factor, which is 

established by the statute at 10-fold, unless there is evidence that another level is protective. When 

making determinations about the magnitude of the FQPA safety factor, the EPA considers the 

completeness of the database and specifically the findings from the developmental and reproductive 

toxicity studies to determine if there is evidence that infants and children are more sensitive than 

adults. Therefore, the magnitude of the FQPA safety factor (usually 1X, 3X, or 10X) is a 

comparative parameter that may be used as an indication of the potential risks to infants and 

children and for overall developmental and reproductive toxicity findings.

Dicamba risk assessments for both acute and chronic effects utilize an FQPA safety factor of 1X. 

This is also the case for 15 of the 18 alternate herbicides, although in some cases, an acute dietary 

risk assessment was not necessary due to a lack of acute toxicity effects. For lactofen, acifluorfen, 

and mesotrione, a 3X or 10X FQPA safety factor was used for the acute and/or chronic 

assessments, indicating a higher level of risk or uncertainty. Therefore, Monsanto concludes that 

dicamba offers an improved potential risk profile for infants and children compared to these three 

alternative herbicides, which are marked with a “Yes” in the Infants & Children Risk column in 

Table A-30. All other alternative herbicide a.i.’s which have an FQPA safety factor of 1X are judged 

to have similar potential risk as dicamba, and are marked with “Neutral” in Table A-30.85

A.3.7.3.2. Comparisons for Ecological Effects

DT soybean can be treated with preemergence and postemergence in-crop applications of dicamba. 

Such a weed control treatment regime has the opportunity to reduce risks to aquatic fish and 

invertebrates by: 

 Replacing currently-used or foreseeable future alternative herbicide products that have 

higher aquatic toxicity risk profiles; and

 Addressing hard-to-control broadleaf weeds or broadleaf weeds that are resistant to 

glyphosate, PPO inhibitors, or ALS inhibitors, thereby preserving the ability of growers to 

manage weed problems and maximize soybean yield in the least risky manner, recognizing 

the ecological benefits offered by the superior hazard and reduced risk profile of glyphosate 

and the more benign profile of dicamba compared to some of the alternative herbicides.

Aquatic Animals

As mentioned, Table A-27 provides information concerning hazards, potential exposures, and risks 

to fish and aquatic invertebrates for each alternate herbicide and for dicamba. These data allow a 

comparison of the relative aquatic animal safety among the optional weed control products on the 

basis of:

 Potency against the indicator species;

 Estimates of potential exposure to aquatic animals; and
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 438 of 946

 Calculated RQs for aquatic animals, by combining the hazard and exposure parameters. The 

RQs that exceed the EPA’s LOC for non-listed aquatic animal species of 0.5 are marked in 

bold font.

The assessment and comparisons summarized in Table A-30 establish that dicamba poses little acute 

risk to aquatic animals, which is consistent with EFED’s assessment published in the RED EFED 

Chapter. Furthermore, for 16 of the 18 alternate herbicides, aquatic animal RQs range from < 0.005 

to 0.05, and do not present a risk to aquatic animals even using a worst-case upper bound exposure 

estimation. Only 2,4-D (the esters form) and lactofen exceed the LOC of 0.5 using conservative 

“worst-case” exposure estimates. These are highlighted in bold font. Monsanto notes that EPA 

considers the LOC for aquatic animals that are listed as endangered or threatened species to be 0.05 

and the LOC for acute restricted use to be 0.1. If the 10-fold to 5-fold lower level of concern were 

applied, flumioxazin would also exceed the LOC based on this “worst-case” exposure estimate.

In addition to the calculated RQs, product labels for five of the alternative herbicides bear EPArequired warning statements for toxicity to fish or invertebrates, based on the hazard values (low 

LC50 or EC50) of those herbicides. These are flumioxazin, cloransulam-methyl, flumiclorac-pentyl, 

lactofen, and 2,4-DB.

Therefore, Monsanto concludes that dicamba presents a lower risk potential for aquatic animals 

compared to three of the 18 alternate herbicides: 2,4-D, flumioxazin, and lactofen. This conclusion 

is tabulated in the Table A-30 scorecard by a “Yes” in the relevant column. The alternative 

herbicide a.i.’s that have a “worst-case” RQ < 0.05 are similar to dicamba in regards to potential 

aquatic animal risk, and are marked “Neutral” in Table A-30.

85

Aquatic Plants

As mentioned, Table A-28 provides information concerning hazards, potential exposures, and risks 

to aquatic plants for each alternate herbicide and for dicamba. These data allow a comparison of the 

relative aquatic plant safety among available weed control products on the basis of:

 Potency against the indicator species;

 Estimates of potential exposure to aquatic plants; and

 Calculated RQs for aquatic plants, by combining hazard and exposure parameters. The RQs 

that exceed the EPA’s LOC for non-listed aquatic plant species of 1.0 are marked in bold 

font.

The data format, sources, and methods are identical to those described above for the aquatic animals 

(Table A-27). A Level of Concern (LOC) value of 1.0 has been used for judging RQ exceedances in 

the case of aquatic plants, consistent with EPA EFED’s normal practices.

The assessment and comparison summarized in Table A-30 establishes that dicamba poses little 

acute risk to aquatic plants, which is consistent with EFED’s assessment published in the RED 

EFED Chapter (U.S. EPA, 2005a) and discussed above. Monsanto was unable to locate public 

aquatic plant hazard data for three of the alternate herbicides (imazaquin, chlorimuron-ethyl, and 

flumiclorac-pentyl). For 9 of the 18 alternatives, the worst case RQs ranged between < 0.02 and 

0.75; and do not present a risk to aquatic plants even using a worst-case upper bound exposure 

estimation. However, for seven alternative herbicides, the worst-case RQs did exceed EFED’s LOC 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 439 of 946

of 1.0. It is not surprising that some herbicides are quite toxic to aquatic plants. The worst-case 

RQs for three of the alternate herbicides (flumioxazin, paraquat dichloride, and lactofen) exceeded 

the LOC by a factor of more than 50-fold.

Therefore, Monsanto concludes that dicamba presents a lower risk potential to aquatic plants 

compared to seven of the 18 alternative herbicides: 2,4-D (ester form), flumioxazin, sulfentrazone, 

thifensulfuron, paraquat dichloride, lactofen, and mesotrione.85 This conclusion is tabulated in the 

Table A-30 scorecard by a “Yes” in the relevant column. The other alternative herbicide a.i.’s, for 

which RQs are less than EPA’s LOC, have similar non-target aquatic plant risk potentials as 

dicamba, and are marked in Table A-30 with “Neutral”. The three herbicides for which no relevant 

data were available are marked as “NA”.

A.3.7.3.3. Comparison for Efficacy and Weed Management, Including Weed Resistance

Comparison of Weed Management Efficacy 

As mentioned, Table A-29 compares weed control effectiveness of formulated products containing 

dicamba and the alternative herbicides. The various products’ overall effectiveness can be compared 

using the simple method of counting the fully-black circle symbols, which identify instances of 

commercial level weed control. Dicamba provides commercial control for 23 of the listed weeds 

(primarily broadleaf species), which is the most of any of the herbicides in the table; dicamba offers 

commercial control for 13 of the herbicide-resistant biotypes and 10 of the hard-to-control species. 

After dicamba, preemergent treatments with 2,4-D, or postemergent treatments with glufosinate, 

tembotrione, and imazethapyr plus glyphosate, are the next most effective herbicides against this 

target group of weeds. The least effective herbicides in this analysis against these targeted weeds and 

resistant biotypes are 2,4-DB, paraquat, imazethapyr alone, flumiclorac-pentyl, chlorimuron-methyl 

and fluthiacet. To summarize the comparative herbicidal effectiveness in this analysis, the scorecard 

in Table A-29 contains a column in which those herbicides that provide commercial control of 50% 

or fewer weeds compared to the number of weeds controlled by dicamba (i.e., eleven or fewer fullyblack circles in Table A-29) are marked with a “Yes”, to denote a clear dicamba advantage. 

Alternative herbicide a.i.’s that provide commercial control of greater than 50% of the number of 

weeds controlled by dicamba (i.e., 12 or more fully-black circles in Table A-29) are marked in Table 

A-30 with “Neutral”, meaning are judged similar to dicamba. The 50% threshold criterion is 

Monsanto’s arbitrary choice that is intended to identify herbicide options that are expected to 

provide substantially poorer weed control compared to dicamba.

Comparison for Weed Management Practices

Beyond direct efficacy against the key weeds, other advantages of DT soybean treated with dicamba 

exist.

Increased Weed Control Flexibility 

DT soybean will allow more flexibility for control of weeds just prior to or at planting of the crop, 

due to elimination of preplant intervals or plant back restrictions on present dicamba labels. These 

restrictions were in place due to concern over potential soybean injury, which is not a concern for 

DT soybean. Current common practice is to use 2,4-D for preemergent burndown treatment. 

When applied too close to soybean planting, 2,4-D can potentially reduce crop stands and cause 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 440 of 946

injury to new seedlings (Thompson et al., 2007). Restrictions have been implemented for most 

products and are as follows: rates up to 0.5 lb a.i. per acre must be applied at least seven days prior 

to planting; rates between 0.5 and 1 lb a.i. per acre must be applied at least 30 days prior to planting. 

Additionally, several sulfonylurea herbicides can also be utilized for preemergent burndown weed 

control in soybean. For example, Canopy herbicide can be applied prior to planting with the 

following restrictions: rates of 2.2 oz per acre or less should be applied at least seven days prior to 

planting; rates of 2.2 to 3.3 oz per acre should be applied at least 14 days before planting. 

Current recommendations to control glyphosate-resistant biotypes of waterhemp and Palmer 

amaranth include the use of a residual herbicide treatment and postemergent applications of PPOinhibiting herbicides such as Cobra (lactofen), Ultra Blazer (acifluorfen), or Cadet (fluthiacet). It is 

commonly known that these postemergent herbicides can cause excessive injury to soybean, 

especially under hot and sunny conditions. Soybean injury, caused by acifluorfen from early (V2 to 

V3 growth stage) or late postemergence (V5 to V6) applications, was seen as increased chlorosis and 

stunting that translated into yield reduction (Young et al., 2003). Furthermore, Legleiter et al. (2009)

illustrated the effectiveness of preemergent herbicides for the control of resistant waterhemp 

populations and demonstrated inconsistent control with PPO-inhibiting herbicides or herbicide 

combinations for the control of waterhemp populations with multiple resistance to glyphosate and 

PPO-inhibiting herbicides. The introduction of DT soybean will provide an effective management 

option for herbicide-resistant biotypes of waterhemp and Palmer amaranth that is not expected to 

cause either crop injury or yield loss.

Residual herbicides containing sulfentrazone, dimethenamid, pendimethalin, metribuzin, or 

metolachlor have been shown to control waterhemp and Palmer amaranth; however, such products 

can present other challenges. Limitations include the need of adequate soil moisture for activation, 

potential crop injury, crop rotation restrictions, and use restrictions based on soil type. As an 

example, metribuzin should not be used on sands, loamy sands, and sandy loams with less than 1% 

organic matter86, and pendimethalin applied after crop-emergence can result in soybean injury.87

For some residual herbicides, there are extensive rotational crop restrictions, ranging from four to 40 

months after application, to avoid subsequent crop injury to the rotated crop caused by herbicide 

remaining in the soil. These limitations reduce the choice of crops that can be planted in case the 

soybean crop is destroyed by weather or even the following growing season. Examples of planting 

limitations among the alternate herbicides are shown in Table A-31.

 

86 Product label for Metribuzin 75 DF (http://www.cdms.net/LabelsMsds/LMDefault.aspx?pd=7614&t=). 

87 Product label for Pendimax 3.3 (http://aesop.rutgers.edu/~plantbiopath/links/bbcpestweb/GrapeLabels/pendimax33.pdf). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 441 of 946

Table A-31. Planting Restrictions (months) for Alternative Herbicide Products

CROP

Herbicide Product

(Active Ingredient)

Authority MTZ 

(sulfentrazone 

+ metribuzin)

Pursuit 

(imazethapyr)

CANOPY EX 

(chlorimuron + 

tribenuron)

Raptor 

(imazamox)

Field corn 4 8.5 8 8.5

Wheat 4 4 4 9

Cotton 12 18 8 9

Peanut 12 0 15 9

Sorghum 12 18 9 3

Onions 18 40 30 9

Dicamba does not have rotational restrictions for such extended time periods and provides a 

substantial advantage in flexibility. For the majority of crops, no rotational restrictions apply after 

120 days following dicamba applications. Specifically, there are no rotational restrictions for 

planting corn following a dicamba application. For cotton, a rotational restriction of 21 days is 

recommended. To summarize this advantage, Table A-30 includes a column in which a “Yes” is 

marked for those alternative herbicides that include substantial rotational or replanting restrictions. 

Entries for alternative herbicide a.i.’s that do not require long rotation intervals are judged similar to 

dicamba, and are marked in Table A-30 with a “Neutral” in the relevant column. 

Furthermore, in situations where sequential herbicide applications were employed to control 

common waterhemp populations, reduced soybean yields have been reported. Yield reductions up 

to 19% compared to a non-treated control were reported when acifluorfen or fomesafen was the 

postemergent herbicide (Soltani et al., 2009). These reduced yields were associated with crop injury 

(chlorosis and stunting) following postemergent applications of certain herbicides, especially PPO 

inhibitors (Baumann et al., 2010; Loux et al., 2009). 

Dicamba treatments in DT soybean provide excellent crop safety. Table A-30 includes a column in 

which the crop injury potential versus dicamba is summarized; a “Yes” entry indicates a substantial 

potential for visible soybean injury. Entries for alternative herbicide a.i.’s with good soybean crop 

safety are judged to be similar to dicamba, and are marked with a “Neutral” in the relevant column 

of Table A-30. In conclusion, the introduction of DT soybean will provide an additional mode-ofaction for postemergent weed control with excellent crop safety.

Weed Spectrum Benefits

Dicamba provides control of over 95 annual and biennial weed species, and control or suppression 

of over 100 perennial broadleaf and woody species. Dicamba provides more effective preemergent 

weed control than 2,4-D on cutleaf evening primrose, clover, and chickweed (Loux et al., 2009). 

Furthermore, dicamba provides excellent control compared to 2,4-D on summer annuals, including 

those with a prostrate growth habit such as knotweed and purslane. With regard to perennial weeds, 

research conducted at North Dakota State University indicates that dicamba is more effective in 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 442 of 946

controlling Canada thistle compared to 2,4-D and effectively controls field bindweed (Zollinger, 

2000; NDSU, 2010b).

Dicamba also provides excellent control of wild buckwheat, while 2,4-D has only limited activity and 

provides inadequate control (Zollinger et. al, 2006). Other preemergent or postemergent herbicides 

often provide incomplete control of wild buckwheat, including dinitroanilines or PPO inhibitors. 

The most effective herbicides for buckwheat are dicamba, and some sulfonylurea products; 

however, some of the sulfonylurea herbicides may persist and carry over for more than one growing 

season, especially in high pH soils. 

Dicamba has been valued as more efficacious on lambsquarters than fomesafen or acifluorfen based 

on university weed control guidelines (Moechnig et al., 2010; University of Illinois, 2008; Legleiter et 

al., 2009; Loux et al., 2009). In addition, dicamba exhibits improved control of sicklepod (Loux et 

al., 2009), kochia and common ragweed (Legleiter et al., 2009), and waterhemp (Soltani et al., 2009) 

compared to fomesafen and acifluorfen. 

Comparison for Herbicide-Resistant Weeds 

The development of weed resistance reduces the effectiveness of all major herbicide classes used in 

soybean production today, including glyphosate, thereby jeopardizing soybean yields and requiring 

the introduction of new tools to control populations of resistant weeds. It is widely recognized that 

utilizing herbicides with different modes-of-action in conjunction with established products is 

especially effective combating further weed resistance development and to provide control of 

existing populations (Beckie, 2006). Preplant / preemergent or early-postemergent in-crop 

applications of dicamba in DT soybean will introduce a new mode-of-action; thus the introduction 

of dicamba use on DT soybean holds great promise for addressing current and future weed 

management needs in soybean. The primary basis for this promise is the wide spectrum of activity 

of dicamba on broadleaf weed species, which are the most common hard-to-control species and 

resistant weed biotypes in soybean production today. 

Dicamba belongs to the auxin agonist class of herbicides, which is the oldest class of known 

synthetic herbicides. This class includes 2,4-D, 2,4-DB, mecoprop, MCPA, clopyralid, and several 

other active ingredients, and is WSSA Herbicide Group Number 4.88 On the basis of their structural 

and chemical properties, auxinic herbicides have been classified into several sub-groups, i.e., 

phenoxyalkanoic acids (e.g., 2,4-D, MCPA), benzoic acids (e.g., dicamba, chloramben), pyridines (e.g., 

picloram, clopyralid), and quinolinecarboxylic acids (e.g., quinclorac, quinmerac). Generally, auxinic 

herbicides are effective against broadleaf (dicotyledonous) plant species, allowing them to be used in 

production of narrow leaf (monocotyledonous) crops such as corn and wheat. The relative 

occurrence of herbicide-resistant weeds differs between the different sub-groups of auxinic 

herbicides. The largest number of resistant weed biotypes has been found for 2,4-D. Considering 

that auxinic herbicides have been widely used in agriculture for more than 60 years, the occurrence 

of weed resistance to this class is relatively low (28 species worldwide, to date) and its development 

 

88 There are several systems of herbicide mode-of action classification. Among the most widely used are those of the Herbicide 

Resistance Action Committee (HRAC) and the Weed Science Society of America. The classifications are compared in a chart at 

http://www.plantprotection.org/HRAC/Bindex.cfm?doc=MOA.html
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 443 of 946

has been slow, especially when compared to the speed of appearance of resistance to ALS inhibitors 

(107 species) or triazine-resistant populations (68 species).89 The relatively low incidence of auxinic 

herbicide resistance is believed to be attributable to the fact that there are multiple mechanisms of 

action for these herbicides (Gressel et al., 1982; Morrison and Devine, 1994). 

Only five weed species have been reported to date to be resistant to dicamba worldwide: kochia 

(Kochia scoparia)

90, lambsquarters (Chenopodium album)91, prickly lettuce (Lactuca serriola), common 

hempnettle (Galeopsis tetrahit) and wild mustard (Brassica caber)

92. Of these five species, resistant 

populations of lambsquarters have only been reported in New Zealand. Regarding the two species 

with resistant populations in the U.S. (kochia, prickly lettuce) and Canada (common hempnettle and 

wild mustard), all were common to cereal production areas in the Western U.S. and Canada. No 

dicamba-resistant populations have been reported in the main soybean production areas, including 

the Midwest, the South and the East coast of the U.S. Table A-30 shows the number of U.S. weed 

species known to have resistance to each of the major herbicide groups (or sub-groups within 

groups, as appropriate) to which the alternative herbicides belong. It also contains a “Yes” marker 

for those herbicides that have many more known resistant weed biotypes than the five known for 

dicamba, indicating a potential lower risk for weed resistance development for dicamba compared to 

alternative herbicides. Entries not indicated with a “Yes” mean that dicamba is either comparable or 

less benign than the alternative herbicide. A comparison of each individual herbicide in the class is 

not provided. 

Although dicamba resistance exists, weed populations that are resistant to dicamba in U.S. soybean 

cropping areas have not been problematic to date, possibly because selection pressure on summer 

annual weeds has been low. Dicamba has seen very limited use in soybean (1.2% of treated soybean 

acres as a preplant and pre-harvest applications) and currently has relatively low usage in the crops 

that are commonly rotated with soybean (10.3% of corn acres as preplant and in-crop applications, 

9.6% of cotton acres as a preplant application, and 7.4% of wheat acres, respectively) (Table A-2 of 

this appendix), although historically dicamba was used more extensively in corn. In addition, there 

are over 20 commercially-available pre-mixed multiple-herbicide formulations that contain dicamba, 

so dicamba is often used in combination with other herbicide modes-of-action. It is expected that 

selection pressure favoring the development of dicamba-resistant weeds will continue to be low even 

after in-crop use of dicamba on DT soybean is approved. Monsanto believes this is because 

dicamba will predominantly still be used in combination with other herbicides exhibiting different 

modes-of-action, principally glyphosate, but also with other soil-active herbicides. The presence of 

multiple herbicides in the weed management system greatly diminishes the likelihood of weed 

resistance to dicamba developing to a level of predominance in weed populations. Dicamba is an 

excellent complement to the weed control spectrum of glyphosate, and it has a relatively low cost 

 

89 Weed Science Society of America. http://www.weedscience.org/summary/MOASummary.asp [Accessed May 28, 210]

90 “Dicamba Resistance in Kochia”. H. J. Cranston, A. J. Kern, J. L. Hackett, E. K. Miller, B. D. Maxwell and W. E. Dyer, Weed 

Science 49:164-170, 2001.

91

 “Chemical Control Options for the Dicamba Resistant Biotype of Fathen (Chenopodium album)”. A. Rahman, T. K. James, and M. 

R. Trolove, New Zealand Plant Protection 61: 287-291, 2008.

92 “Inheritance of Dicamba Resistance in Wild Mustard (Brassica Kaber)”. M. Jasieniuk, I. N. Morrison and A. L. Brûlé-Babel, Weed 

Science 43:192-195, 1995.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 444 of 946

and low potential for crop injury to DT soybean relative to other broadleaf weed options. Taken 

together, these factors will help to ensure that more fields receive weed-control treatments using 

multiple herbicide modes-of-action, in a proactive way, aimed at mitigating the potential for 

development of resistance. In general, this will serve to further reduce the development of weed 

resistance to all herbicides, which target broadleaf weeds in soybean production, and in crops 

rotated with soybean. (See Appendix B of this EIR for more information on herbicide-resistant 

weeds in soybean systems.)

As part of the projected role of dicamba as a companion herbicide for glyphosate, dicamba will 

provide growers with a new mode-of-action for use in-crop against summer annual broadleaf weeds. 

Dicamba will help prevent and/or combat existing weed resistance issues that can limit effectiveness 

of the PPO- and ALS-inhibiting herbicide classes. Herbicides from these two herbicide classes have 

historically dominated the non-glyphosate broadleaf weed control tools available in soybean (13 of 

the 18 alternative herbicides considered here are PPO- or ALS-inhibiting herbicides (Table A-30)), 

and were the predominant modes-of-action used for weed control in soybean production prior to 

the introduction of the Roundup Ready soybean system; they remain the primary options 

recommended for management of glyphosate-resistant or hard-to-control broadleaf weeds in 

soybean. For example, fomesafen and flumioxazin, both PPO Inhibitors, are the primary herbicides 

recommended for control of glyphosate-resistant Palmer amaranth (pigweed) in soybean.

Dicamba will foster the adoption of Integrated Pest Management (IPM) practices in soybean by 

allowing growers to continue to primarily focus on postemergent in-crop weed control, as they have 

practiced with Roundup Ready soybean, and will make current practices more effective by providing 

an additional mode-of-action herbicide. This will allow growers to delay some herbicide treatments 

until field scouting indicates a need for additional weed control, which is consistent with the 

principles of IPM. Dicamba, as a companion product to glyphosate, will also continue to foster 

adoption of and maintain the use of conservation tillage practices, because of grower preference to 

use postemergent products, such as dicamba on DT soybean, compared to reliance on soil-active 

preemergent products

In summary, the ability to use dicamba as part of a weed management program in U.S. soybean 

production will provide significant benefits for managing broadleaf weed resistance, not only relative 

to glyphosate, but also to other herbicides such as those included in PPO- and ALS-inhibitor classes. 

There is evidence in the scientific literature from data generated in field studies and from model 

simulations that the application of multiple herbicides, each effective in controlling a weed spectrum, 

with more than one mode-of-action can significantly mitigate the potential for evolution of resistant 

populations within a field (Powles et al., 1996; Beckie, 2006). In addition, there is evidence that 

resistance would be mitigated more effectively by use of herbicide mixtures than by using an 

herbicide rotation strategy (Diggle et al., 2003; Beckie and Reboud, 2009). Based on this general 

information on resistance, Monsanto believes that application of dicamba on DT soybean integrated 

into the Roundup Ready soybean system will reduce the development of herbicide-resistant 

broadleaf populations to glyphosate and other herbicides. This conclusion is based on the 

following: 1) the efficacy and broad spectrum of glyphosate and weed control spectrum of dicamba, 

2) the low level of dicamba-resistant broadleaf weeds in the major soybean production areas, 3) the 

low number of species resistant to glyphosate, 4) the expected use of dicamba applied to DT 

soybean, and 5) the fact that dicamba will be used in combination with glyphosate, and other 

alternative herbicides as necessary to control problematic weeds. Using available information, 

Monsanto conservatively estimates that dicamba use on DT soybean could reduce the growth of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 445 of 946

resistant weed populations on five to ten percent of the expected 77 million U.S. planted soybean 

acres (Table A-32), which is equal to approximately 3.6 to 7.2 million acres.

Table A-32 Soybean Production in the U.S., 1999 – 20121

Year

Acres 

Planted

(×1000)

Acres 

Harvested

(×1000)

Average

Yield

(bushels/acre)

Total

Production

(×1000 bushels)

Value

(billions $)

2012 77,198 76,104 39.6 3,014,998 43.19

2011 75,046 73,776 41.9 3,093,524 38.50

2010 77,404 76,610 43.5 3,329,181 37.55

2009 77,451 76,372 44.0 3,359,011 32.15

2008 75,718 74,681 39.7 2,967,007 29.46

2007 64,741 64,146 41.7 2,677,117 26.97

2006 75,522 74,602 42.9 3,196,726 20.47

2005 72,032 71,251 43.1 3,068,342 17.30

2004 75,208 73,958 42.2 3,123,790 17.90

2003 73,404 72,476 33.9 2,453,845 18.02

2002 73,963 72,497 38.0 2,756,147 15.25

2001 74,075 72,975 39.6 2,890,682 12.61

2000 74,266 72,408 38.1 2,757,810 12.47

Ave. 74,310 73,220 40.6 2,976,014 24.76

1

Source is USDA-NASS (2013a)

Furthermore, Monsanto believes the opportunity for dicamba use on DT soybean will foster 

continued adoption of conservation tillage practices, an important goal for the agro-ecosystem and 

the long term sustainability of U.S. agriculture. Presently, 41.5% of an estimated 74 million acres of 

U.S. soybean acres, or 30.6 million acres, employ no-till or conservation tillage production systems 

(CTIC, 2007). The introduction of DT soybean into the Roundup Ready soybean system would 

allow the flexibility to incorporate an additional herbicide mode-of-action in both pre- or 

postemergent applications, and support the continued use of conservation tillage production 

systems. The benefits of conservation tillage are well known and demonstrated, including soil and 

water conservation, improved environmental (e.g., water) quality, and a reduced carbon footprint 

(Arriaga and Balkcom, 2005; Reicosky, 2008). These conservation tillage acres will represent a 

significant portion of the 30 million total acres projected for DT soybean planting, in turn 

representing a significant number of acres where mitigation of the development of glyphosateresistant biotypes could be expected to occur. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 446 of 946

A.4. IMPACT OF DGT COTTON DEREGULATION 

A.4.1. Impact of DGT Cotton Deregulation on Dicamba Usage 

A.4.1.1. Overview

The deregulation and commercialization of DGT cotton will expand dicamba use to in-crop 

postemergence applications to address hard-to-control and herbicide-resistant broadleaf weeds 

found in U.S. cotton production. The impact that DGT cotton will have on overall dicamba use will 

depend on the level of DGT cotton adoption by growers. Therefore, the extent of DGT cotton 

acreage following the deregulation of DGT cotton is difficult to forecast. Monsanto estimates that 

dicamba-treated acres could ultimately reach 50% of the total U.S. cotton acres. This estimate is 

based on a number of factors, including: (1) the percentage of non-glyphosate herbicides currently 

used in glyphosate-tolerant cotton; (2) the development of glyphosate-resistant weeds; (3) the 

effectiveness of other non-glyphosate herbicides used in the glyphosate-tolerant cotton weed control 

systems; (4) the perceived risk of offsite movement onto dicamba-sensitive crops; and (5) the 

foreseeable future introduction of new competitive GE-derived traits in cotton.

Approximately 53% to 64% of growers used a non-glyphosate herbicide in addition to glyphosate in 

the glyphosate-tolerant cotton systems in 2005 (Givens et al., 2009b). In 2007, approximately 39% 

of the growers often or always used herbicides with different modes-of-action in the glyphosatetolerant cotton systems (Frisvold et al., 2009). Regardless of the availability of DGT cotton, the 

future use of non-glyphosate herbicides is expected to increase in order to support the management 

of glyphosate-resistant weeds. Additionally, grower educational programs on weed resistance 

management conducted by industry and universities encourage the use of non-glyphosate herbicides 

with alternative modes-of-action in glyphosate-tolerant cropping systems as a proactive measure to 

minimize the potential for development of glyphosate-resistant weeds (Beckie, 2006; Beckie, 2011; 

Powles, 2008). These programs will likely drive a further increase in non-glyphosate herbicides 

applied in cotton production. 

A second factor impacting dicamba-treated cotton acreage is the current and future need for control 

of glyphosate-resistant weeds. Glyphosate-resistant weeds have been identified in multiple states 

(Heap 2012). When a glyphosate-resistant weed biotype has been confirmed to be present in a 

geographical area, growers in that area are advised proactively to implement glyphosate-resistant 

weed management programs to ensure effective control of the resistant weed biotype regardless of 

whether the weed species has been confirmed to be resistant on a grower’s farm. Therefore, the 

acreage in an area where responsive weed resistance management practices are implemented is 

potentially greater than the actual acres known to be impacted by glyphosate-resistant weeds. 

University weed scientists recommend that growers implement best management practices, 

including a non-glyphosate herbicide with a second mode-of-action, in their cropping systems to 

minimize the development and potential spread of glyphosate-resistant weeds in the future 

(Culpepper et al., 2013; Hurley et al., 2009; Norsworthy et al., 2012; Owen et al., 2011; University of 

Georgia, 2012).

It is anticipated that even in locations where glyphosate-resistant weeds are present, glyphosate will 

continue to be the base herbicide applied to DGT cotton as a combined trait product with 

glyphosate-tolerant cotton. Table A-33 provides a summary of the herbicide applications registered 

for use in cotton in 2011, demonstrating that herbicides are used on essentially all (>99%) cotton 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 447 of 946

acres in the U.S (Brookes, 2012; Monsanto Company, 2012). Approximately 39 million pounds of 

herbicide active ingredient were applied to cotton in 2011. These alternative herbicides will compete 

with dicamba and are expected to reduce the potential dicamba use on DGT cotton integrated into 

the glyphosate-tolerant cotton systems and in future combined trait products containing DGT 

cotton. 

Another factor influencing the number of dicamba-treated cotton acres in the future will be the 

introduction of competing herbicide-tolerant traits in cotton. Currently, there are numerous 

herbicide-tolerant cotton products that are under regulatory review or have recently been authorized. 

This includes several products that have tolerance to multiple herbicides with different modes-ofaction. These new GE-derived herbicide-tolerant cotton products are anticipated to be introduced 

in future years and will compete with Monsanto’s DGT cotton and glyphosate-tolerant cotton 

products, thereby further reducing the potential dicamba use in cotton.

Taking into consideration the above assessment, the potential acreage of DGT cotton treated with 

dicamba is estimated to be 50% of the U.S. cotton acres, and would result in approximately 5.2 

million pounds a.e. of dicamba applied to DGT cotton annually (including preplant, preemergence, 

and in-crop applications). Currently, 364,000 pounds of dicamba are applied preplant to 

commercially available cotton (see Table A-2). It is anticipated that dicamba applications will 

continue for all other currently labeled crops at the current annual level of approximately 3.8 million 

pounds (see Table A-2). Therefore, the addition of the estimated 5.2 million pounds of dicamba 

that would be applied to DGT cotton would result in a total U.S. dicamba use of approximately 9 

million pounds annually.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 448 of 946

Table A-33. Herbicide Applications Registered for Use in Cotton in 20111

Herbicide Herbicide Family

Mode-of-Action 

(MOA)

Cotton Acres 

Treated (%)

Cotton Acres 

Treated per 

MOA (%)

Quantity Applied 

(1000 lbs a.i. 2)

Total Quantity 

Applied/MOA 

(1000 lbs a.i.2)

Glyphosate Glycine EPSPS inhibitor 73 73 20,015 20,015

Pendimethalin Dinitroanaline Microtubule 

inhibitor

16 40 1,964 5,043

Trifluralin Dinitroanaline 24 3,079

Diuron Urea

PSII inhibitor

15

34

1,727

3,737 Prometyrn Triazine 10 1,102

Fluometuron Urea 8 870

Linuron Urea <1 38

Acifluorfen Diphenylether <1 1

Carfentrazone Triazolinone

PPO inhibitor

<1

38

<1

856

Flumiclorac Nphenylphthalimide<1 <1

Flumioxazin Nphenylphthalimide19 192

Fomesafen Diphenylether 17 626

Oxyfluorfen Diphenylether 1 36

Pyraflufen Phenylpyrazole <1 <1

2,4-D Phenoxy Synthetic Auxin 17 27 1,659 2,023

Dicamba Benzoic acid 10 364

Pyrithiobac Benzoate ALS inhibitor 14 21 113 120
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 449 of 946

Table A-33 (continued). Herbicide Applications Registered for Use in Cotton in 20111

Herbicide Herbicide Family

Mode-of-Action 

(MOA)

Cotton Acres 

Treated (%)

Cotton Acres 

Treated per

MOA (%)

Quantity Applied 

(1000 lbs a.i. 2)

Total Quantity 

Applied/MOA 

(1000 lbs a.i.2)

Thifensulfuron Sulfonylurea <1 <1

Thibenuron Sulfonylurea <1 <1

Trifloxysulfuron Sulfonylurea 6 6

Acetochlor Chloroacetamide Long-chain fatty 

acid inhibitor

8

25 1,502 4,587

Metolachlor Chloroacetamide 17 3,085

Norflurazon Pyridazinone Inhibition of 

carotenoid

<1 <1 2 2

Paraquat Bipyridylium Photosystem-Ielectron diverter10 10 735 735

GlufosinateammoniumPhosphinic acid Glutamine 

synthesis inhibitor

10 10 800 800

MSMA Organoarsenical Cell membrane 

disruption

6 6 1,066 1,066

Clethodim Cyclohexanedione

ACCase inhibitor

<1

<1

3

3

Fluazifop Aryloxphenoxy 

propionate

<1 <1

Diflufenzopyr Semicarbazone Auxin transport <1 <1 3 3

Clomazone Isoxazolidinone Diterpene 

synthesis inhibitor <1 <1 <1 <1

Total 99.4 38,992

1 Updated version of Table VIII-9 of petition 12-185-01p_a1 with 2011 data (Monsanto, 2012).

2a.i.= active ingredient.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 450 of 946

A.4.1.2. Materials and Methods

This analysis utilizes unpublished grower survey data obtained from an independent, private market 

research company that provides farm-survey information on agricultural herbicide usage in the U.S. 

This information reflects the most current data available on U.S. herbicide usage, and presents data 

on glyphosate-tolerant cotton from 2002 through 2011 to represent herbicide use after widespread 

adoption of glyphosate-tolerant cotton and after glyphosate-resistant weeds had begun impacting 

weed control decisions in cotton cultivation. The majority of data are presented in terms of total 

acres treated (TAT), which is the number of acres treated with an herbicide. The use of TAT 

provides a way to look at herbicide use that is independent of the various use rates of herbicides. If 

an herbicide is used more than once on an acre, the TAT will reflect this multiple use, and 

consequently the TAT may exceed the number of crop acres planted. This method provides a more 

complete view of herbicide use. 

This analysis organizes data in two broad usage sets (Table A-34): preplant/pre-emergence to the 

crop (PRE) and post-emergence in-crop use (POST). The PRE set are herbicides applied prior to 

planting the crop through planting of the crop, but before crop emergence regardless of their modeof-activity. The POST set are herbicides applied after crop emergence regardless of their mode-ofactivity. In glyphosate-tolerant cotton, a total of 38 different non-glyphosate herbicides had been 

used in the PRE timing while 40 non-glyphosate herbicides had been used at the POST timing 

(Table A-34). The total PRE and POST herbicides used in glyphosate-tolerant cotton acres from 

2002-2011 are presented in Table A-35 and Table A-36 below, respectively.

Certain assumptions were made in order to define the level of herbicide use (non-glyphosate and 

glyphosate) in glyphosate-tolerant cotton at a future time when there is peak use of dicamba in DGT 

cotton. One of the assumptions is that total planted cotton acres will be less than the 2011 planted 

acres (i.e., a reduction in planted acres from approximately 14.5 million to approximately 10.5 

million). Monsanto estimates an average planted acreage of 10.5 million acres per year for this 

analysis. Similarly, USDA (2013) predicts a decrease in cotton acreage, with projections for planted 

cotton acreage of 9.3 to 11.3 million acres for 2013 to 2022, with an average of 10.7 million acres per 

year. The predicted reduction is based on expected long-term economic conditions relative to the 

utilization and pricing of cotton. While acreage estimates were used to calculate the predicted 

herbicide use in glyphosate-tolerant cotton, the comparisons between predicted herbicide use in the 

presence or absence of DGT cotton are similar regardless of acreage trends because the same 

predicted acres estimate is used for both analyses. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 451 of 946

Table A-34. Non-Glyphosate Herbicides Used in Cotton from 2002-2011

Preplant/preemergence active ingredients Postemergence active Ingredients

2,4-D 2,4-D

2,4-DB Acetochlor

Alachlor Acifluorfen

Bromoxynil Alachlor

Carfentrazone-Ethyl Bromoxynil

Clethodim Carfentrazone-Ethyl

Clomazone Clethodim

Cyanazine Cyanazine

Dicamba Dicamba

Diflufenzopyr Dimethipin

Diuron Diuron

Fluazifop DSMA

Flumiclorac Fenoxaprop

Flumioxazin Fluazifop

Fluometuron Flumiclorac

Fomesafen Flumioxazin

Glufosinate Fluometuron

Lactofen Fomesafen

Linuron Glufosinate

Metolachlor Hexazinone

Metolachlor-S Lactofen

MSMA Linuron

Norflurazon Metolachlor

Oxyfluorfen Metolachlor-S

Paraquat Metsulfuron

Pendimethalin MSMA

Prometryn Oxyfluorfen

Pyraflufen Ethyl Paraquat

Pyrithiobac-Sodium Pelargonic Acid

Quizalofop Pendimethalin

Rimsulfuron Prometryn

Saflufenacil Pyraflufen Ethyl

Sethoxydim Pyrithiobac-Sodium

Sulfosate Quizalofop

Thifensulfuron Rimsulfuron

Tribenuron Methyl Sethoxydim

Trifloxysulfuron Sulfosate

Trifluralin Trifloxysulfuron

Trifluralin

Total 38 40
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 452 of 946

Table A-35. Total Treated Cotton Acres for PRE Herbicide Applications1

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Projected 

(2012-2020)

TAT nonglyphosate 

herbicides 7,608,153 6,973,079 8,022,758 8,278,629 10,422,198 8,619,214 7,645,112 8,720,633 13,079,934 18,532,420 15,752,557

% increase 

2002-2009 

and 2007-

2011 15% 113%

TAT for 

glyphosate 

only 4,794,054 4,481,055 6,085,131 6,605,653 8,160,846 5,959,715 5,020,737 4,362,308 6,133,464 6,653,710 4,790,671

Total TAT 

(nonglyphosate 

+ 

glyphosate 

herbicides) 12,402,207 11,454,134 14,107,889 14,884,282 18,583,044 14,578,929 12,665,849 13,082,941 19,213,398 25,186,130 20,543,228

GT cotton 

planted 

acres2

10,169,767 9,694,232 10,754,975 11,282,527 11,880,216 9,058,136 7,838,072 7,732,469 9,511,862 13,016,858

Total 

Planted 

Cotton 

acres 14,380,987 13,626,965 13,869,061 14,024,973 15,113,121 10,731,987 9,308,988 9,042,201 10,801,010 14,533,017 10,500,000

1 Unpublished grower survey data (Monsanto, 2012).

2 Estimated.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 453 of 946

Table A-36. Total Treated Cotton Acres for POST Herbicide Applications1

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Projected 

(2012-2020)

Total 

TAT nonglyphosate 

herbicides 4,666,015 4,119,878 4,864,283 4,625,240 5,513,925 2,941,420 3,303,968 3,734,015 6,341,041 11,018,661 9,365,862

% increase 

2002-2007 

and 2007-

2011 -20% 220%

TAT for 

glyphosate 

only 15,663,805 14,563,604 17,877,154 19,609,494 16,647,267 13,536,614 11,128,357 12,128,747 16,761,716 15,615,631 11,243,254

Total TAT 

(nonglyphosate 

+ 

glyphosate 

herbicides) 20,329,820 18,683,482 22,741,437 24,234,734 22,161,192 16,478,034 14,432,325 15,862,762 23,102,757 26,634,292 20,609,116 

GT Cotton 

planted 

acres2 10,169,767 9,694,232 10,754,975 11,282,527 11,880,216 9,058,136 7,838,072 7,732,469 9,511,862 13,016,858

Total 

Planted 

Cotton 

acres 14,380,987 13,626,965 13,869,061 14,024,973 15,113,121 10,731,987 9,308,988 9,042,201 10,801,010 14,533,017 10,500,000

1 Unpublished grower survey data (Monsanto, 2012).

2 Estimated.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 454 of 946

A.4.1.3. Analysis of PRE Cotton Herbicide Use From 2002-2011

The use of non-glyphosate herbicides included in the PRE set is influenced by use of conservation 

tillage (i.e., reliance on herbicides to control emerged weeds prior to crop planting) and use of 

residual herbicides applied preplant and/or preemergent to crop emergence. The use of nonglyphosate PRE herbicides in glyphosate-tolerant cotton was relatively flat from 2002 through 2009 

with only a 15% increase in TAT between 2002 and 2009 (Figure A-3 and Table A-37). In 2009, 

glyphosate-tolerant cotton was grown on 7.7 million acres. In the PRE segment, the primary nonglyphosate herbicides used were those providing postemergence control of broadleaf weeds (e.g., 2,4-

D, paraquat), preplant (e.g., trifluralin, fomesafen, flumioxazin) or preemergence (e.g., pendimethalin) 

control. From 2009 to 2011 there was a 113% increase in the use of non-glyphosate herbicides in 

the glyphosate-tolerant cotton PRE segment. In 2011, glyphosate-tolerant cotton was grown on 

approximately 13 million acres, a 68% increase from 2009. This data suggests that the growth in 

non-glyphosate herbicide use was not driven just by an increase in the total planted acres of 

glyphosate-tolerant cotton. This increase in use of non-glyphosate herbicides in the 2009-2011 time 

period is consistent with the increased emphasis by public and private sectors promoting more 

diversified weed management and also the increase in emergence of glyphosate-resistant weeds 

during the same time period. Regarding future use of non-glyphosate herbicides, this analysis 

projects that non-glyphosate herbicide use will decrease 15% (a decrease from 18.5 million TAT to

approximately 15.8 million), primarily due to an overall decrease in planted acres, even though use 

of non-glyphosate herbicides will increase, particularly in the western cotton markets, regardless of 

the commercialization of DGT cotton. Of the planted glyphosate-tolerant cotton acres in 2011, 

approximately 65% received a non-glyphosate PRE herbicide application (Table A-38). The number 

of glyphosate applications per planted acre of glyphosate-tolerant cotton in the PRE segment has 

remained flat from 2002 through 2011. This figure is not expected to change in the foreseeable 

future regardless of the commercialization of DGT cotton (Table A-38). However, as indicated 

above, the total use of glyphosate per year is expected to decrease due to a projected decrease in 

cotton acres.

 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 455 of 946

Figure A-3. Average Number of Preplant/Preemergence and Postemergence Nonglyphosate herbicide applications in cotton 2002-2011
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 456 of 946

Table A-37. Total Treated Cotton Acres for PRE Herbicide Applications1

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Projected 

(2012-2020)

TAT nonglyphosate 

herbicides 7,608,153 6,973,079 8,022,758 8,278,629 10,422,198 8,619,214 7,645,112 8,720,633 13,079,934 18,532,420 15,752,557

% increase 

2002-2009 

and 2007-

2011 15% 113%

TAT for 

glyphosate 

only 4,794,054 4,481,055 6,085,131 6,605,653 8,160,846 5,959,715 5,020,737 4,362,308 6,133,464 6,653,710 4,790,671

Total TAT 

(nonglyphosate 

+ 

glyphosate 

herbicides) 12,402,207 11,454,134 14,107,889 14,884,282 18,583,044 14,578,929 12,665,849 13,082,941 19,213,398 25,186,130 20,543,228

GT cotton 

planted 

acres2

10,169,767 9,694,232 10,754,975 11,282,527 11,880,216 9,058,136 7,838,072 7,732,469 9,511,862 13,016,858

Total 

Planted 

Cotton 

acres 14,380,987 13,626,965 13,869,061 14,024,973 15,113,121 10,731,987 9,308,988 9,042,201 10,801,010 14,533,017 10,500,000

1 Unpublished grower survey data (Monsanto, 2012).

2Estimated.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 457 of 946

Table A-38. Cotton Base Acres and Average Number of PRE and POST Herbicide Applications in Cotton from 2002-20111

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Preplant/Preemergence

Segment

Base Acres non-gly 5,393,689 5,114,256 5,964,796 5,796,824 7,301,901 5,700,249 4,950,783 5,278,197 6,927,575 8,445,599

% of GT planted acres 53% 53% 55% 51% 61% 63% 63% 68% 73% 65%

Avg # of non-gly apps per 

treated acre 1.41 1.36 1.35 1.43 1.43 1.51 1.54 1.65 1.89 2.19

Base Acres gly 4,206,852 3,944,302 5,015,080 5,139,869 6,244,992 4,840,283 4,113,912 3,737,966 5,022,647 5,632,286

% of GT planted acres 41% 41% 47% 46% 53% 53% 52% 48% 53% 43%

Avg # of gly apps per 

treated acre 1.14 1.14 1.21 1.29 1.31 1.23 1.22 1.17 1.22 1.18

Postemergence Segment

Base Acres non-gly 2,893,224 2,511,625 3,347,572 2,799,905 3,390,985 2,088,573 2,122,123 2,311,575 3,462,215 5,128,952

% of GT planted acres 28% 26% 31% 25% 29% 23% 27% 30% 36% 39%

Avg # of non-gly apps per 

treated acre 1.61 1.64 1.45 1.65 1.63 1.41 1.56 1.62 1.83 2.15

Base Acres gly 9,648,772 9,172,346 10,429,110 10,838,740 10,620,351 8,743,094 7,348,278 7,269,956 9,282,857 9,428,994

% of GT planted acres2 95% 95% 97% 96% 89% 97% 94% 94% 98% 72%

Avg # of gly apps per 

treated acre 1.62 1.59 1.71 1.81 1.57 1.55 1.51 1.67 1.81 1.66

GT cotton planted acres2 10,169,767 9,694,232 10,754,975 11,282,527 11,880,216 9,058,136 7,838,072 7,732,469 9,511,862 13,016,858

Total cotton planted acres 14,380,987 13,626,965 13,869,061 14,024,973 15,113,121 10,731,987 9,308,988 9,042,201 10,801,010 14,533,017

1 Unpublished grower survey data (Monsanto, 2012).

2 Estimated.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 458 of 946

A.4.1.4. Analysis of POST Cotton Herbicide Use From 2002-2011

The use of herbicides from 2002 to 2011 was primarily influenced by the need to control weeds after 

they emerged in the crop or to extend the preemergence residual control of weeds longer into the 

growing season. As in the case of non-glyphosate PRE herbicides, the use of non-glyphosate POST 

herbicides applied in glyphosate-tolerant cotton was flat to slightly reduced use from 2002 to 2009 

(Figure A-3 and Table A-39). However, from 2009 to 2011 there was a 220% increase in TAT for 

the use of non-glyphosate POST herbicides in glyphosate-tolerant cotton. In 2009, glyphosatetolerant cotton was grown on approximately 7.7 million acres, while in 2011 there were 

approximately 13 million planted acres, a 68% increase. As in the case for the PRE herbicides, these 

data indicate that the increase in non-glyphosate herbicide use was not solely related to an increase in 

planted glyphosate-tolerant cotton acres. The increased use of non-glyphosate POST herbicides 

after 2009 is evidence of increased adoption of diversified weed management practices by farmers. 

These outcomes are consistent with farmer adoption of recommendations from the public and 

private sectors on how best to proactively and reactively manage weed resistance. Regarding future 

use of non-glyphosate herbicides in the POST segment, there will be an expected net 15% decrease, 

primarily due to a decrease in the planted acres of cotton, even though there will be increased use in 

certain market segments. In 2011, approximately 39% of glyphosate-tolerant cotton acres received a 

non-glyphosate POST herbicide application (Table A-38). The number of glyphosate applications 

per planted acre of glyphosate-tolerant cotton in the POST segment has remained flat from 2002 

through 2011. This figure is not expected to change in the foreseeable future regardless of the 

commercialization of DGT cotton (Table A-38). However, as indicated above, total use of 

glyphosate per year is expected to decrease due to a projected decrease in cotton acres. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 459 of 946

Table A-39. Total Treated Cotton Acres for POST Herbicide Applications1

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Projected 

(2012-

2020)

Total TAT nonglyphosate herbicides 4,666,015 4,119,878 4,864,283 4,625,240 5,513,925 2,941,420 3,303,968 3,734,015 6,341,041 11,018,661 9,365,862

% increase 2002-2007 

and 2007-2011 -20% 220%

TAT for glyphosate 

only 15,663,805 14,563,604 17,877,154 19,609,494 16,647,267 13,536,614 11,128,357 12,128,747 16,761,716 15,615,631 11,243,254

Total TAT (nonglyphosate + 

glyphosate herbicides) 20,329,820 18,683,482 22,741,437 24,234,734 22,161,192 16,478,034 14,432,325 15,862,762 23,102,757 26,634,292 20,609,116 

GT Cotton planted 

acres2 10,169,767 9,694,232 10,754,975 11,282,527 11,880,216 9,058,136 7,838,072 7,732,469 9,511,862 13,016,858

Total Planted Cotton 

acres 14,380,987 13,626,965 13,869,061 14,024,973 15,113,121 10,731,987 9,308,988 9,042,201 10,801,010 14,533,017 10,500,000

1 Unpublished grower survey data (Monsanto, 2012).

2 Estimated.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 460 of 946

A.4.1.5. Projected Dicamba Use (TAT and Total Pounds) on DGT Cotton

Based upon anticipated use patterns for dicamba on DGT cotton, projections on the number of 

dicamba TAT and total pounds of dicamba used on DGT cotton were determined for the combined 

PRE and POST application timing (Table A-40 and Table A-41). The anticipated use projections 

represent a high-end estimate of the incremental dicamba use. Projected dicamba use at peak 

penetration is 10.8 million TAT and 5.2 million pounds active ingredient (Table A-40 and Table A-41). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 461 of 946

Table A-40. Estimated Dicamba Total Acres Treated at Peak Dicamba Use on DGT Cotton

Cotton Growing 

Region

2011 

planted 

acres 

(000)1

% of 

total 

planted

Planted acres 

at Peak (i.e.

15% 

reduction)

Planted 

conventional 

till acres 

(000) at peak

Planted no 

till acres 

(000) at 

peak2

# dicamba 

applications 

conventional

# dicamba 

applications 

no till

TAT 

assuming 

100% acres 

with DGT 

Cotton

TAT 

with 50% 

dicamba 

use

SE, Delta, E.TX 6,881 46% 5,849 4,621 1,228 1 2 7,077 3,539

CA 637 4% 541 428 114 1 2 655 328

W.TX, AZ, OK, 

NM, KS 7,363 49% 6,259 4,944 1,314 2 3 13,831 6,916

Total 14,881 10,782

1 Acres from USDA-NASS, 2012. Note: Total planted acres for 2011 varies between USDA-NASS and the grower survey data used in previous tables. USDA-NASS 

was used to calculate dicamba TAT in the different cotton growing areas because only USDA-NASS planted acres is broken out by state. 

2 Based on 21% of cotton acres being no till. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 462 of 946

Table A-41. Estimated Dicamba Total lbs a.i. at Peak Dicamba Use on DGT Cotton

Cotton 

Growing 

Region

Tillage 

system

2011 

planted 

acres 

(000) 

available 

for 

dicamba 

use1

Planted 

acres at 

Peak (i.e.

15% 

reduction)

Planted 

conventional 

till acres 

(000) at Peak

Planted 

no till 

acres 

(000) at 

Peak

Conventional 

Tillage: # 

dicamba incrop 

applications

Conservation 

tillage: # 

dicamba 

apps in crop2

Conservation 

Tillage: # 

dicamba 

application 

preplant

Conventional 

Tillage: 

Dicamba 

rate in-crop

Conservation 

tillage: 

Dicamba 

Rate 

Preplant

Total lbs 

dicamba 

ai (000)

SE, Delta, 

E.TX

Conventional 2,310 1 0.5 1,155

Conservation 614 1 1 0.5 0.375 537

Total 3,441 2,924 1,693

CA

Conventional 214 1 0.5 107

Conservation 57 1 1 0.5 0.375 50

Total 319 271 157

W.TX, 

AZ, OK, 

NM, KS

Conventional 2,472 2 0.5 2,472

Conservation 657 2 1 0.5 0.375 904

Total 3,682 3,129 3,376

US Total 5,225

1 Acres from USDA-NASS, 2012. Note: Total planted acres for 2011 varies between USDA-NASS and the grower survey data used in previous tables. USDA-NASS 

was used to calculate dicamba TAT in the different cotton growing areas because only USDA-NASS planted acres is broken out by state. 

2 Based on 21% of cotton acres being no till.. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 463 of 946

A.4.2. Displacement of Other Non-Glyphosate Herbicides by Dicamba Use Following 

Deregulation of DGT Cotton

A.4.2.1. Materials and Methods

In order to estimate the amount of non-glyphosate herbicides that could be replaced by dicamba, 

Monsanto weed scientists identified those herbicides most likely to be replaced by dicamba from the 

list of non-glyphosate herbicides currently being used in glyphosate-tolerant cotton (Table A-34). 

These herbicides were selected based on criteria such as lower efficacy, carryover concerns, existing 

resistance, use restrictions, and/or crop safety. This resulted in the selection of 20 and 16 nonglyphosate herbicides in the PRE and POST segments, respectively, that would likely be replaced to 

some level by dicamba use. The herbicides expected to be replaced by dicamba in the PRE set 

included, among others, diflufenzopyr, fluometuron, diuron, flumioxazin, pendimethalin, fomesafen, 

trifluralin, 2,4-D, paraquat, and prometryn (Table A-42). The herbicides in the POST set most likely 

to be replaced by dicamba included, but were not limited to, paraquat, fomesafen, pyrithiobac, 

MSMA, fluometuron, diuron, prometryn, flumioxazin, trifloxysulfuron, metolachlor-s, metolachlor 

and acetochlor (Table A-43). In addition, the percent replacement for each herbicide was estimated 

based upon a technical understanding of the herbicide products and the marketplace, and then the 

herbicides were grouped based upon these estimates. 

Glyphosate use in glyphosate-tolerant cotton has remained relatively constant over the last decade 

and is not projected to fluctuate in use per acre in the future, but on a total use basis will decrease 

due to overall reduction in planted cotton acres (Table A-38). However, there was a noticeable drop 

in glyphosate use in the POST segment in 2011, as a percent of glyphosate base acres relative to GT 

planted acres, relative to prior years (Table A-38). It is not known if this is the beginning of a trend 

towards reduced glyphosate use or a result of causes unique to 2011. In 2011, there were a 

significant number of acres that were not harvested because of the drought and it is possible that 

farmers delayed herbicide applications and subsequently never made some POST applications.

To obtain an accurate estimate of the amount of herbicide that dicamba could potentially displace, it 

was necessary to estimate the number of acres that would be planted to DGT cotton and the 

number of dicamba-tolerant acres that would be treated with dicamba at peak market penetration. 

Monsanto estimates that DGT cotton varieties could be planted on up to 50% of the U.S. cotton 

acres at peak penetration and that dicamba will be used in 100% of these planted acres. This value 

represents a high-end estimate of incremental dicamba use. It is possible that the actual market 

penetration and associated dicamba use could be lower.

Additional analyses were conducted for each application timing segment to evaluate trends in 

glyphosate and non-glyphosate use and to allow for a comparison of the pounds of herbicide 

applied with and without the commercialization of DGT cotton. These analyses include use of base 

acres as provided by the market research company (a base acre is defined as one to which at least 

one glyphosate or non-glyphosate herbicide application has been applied). This contrasts with TAT 

which accounts for multiple applications on an acre.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 464 of 946

Table A-42. Projected Total Acres Treated for PRE Cotton Herbicides Likely to be 

Displaced by Dicamba

20111 Peak

Active 

Ingredients

Projected 

% 

Replacem

ent

Major 

Reasons for 

replacement

TAT 50% of 

Total 

TAT2

TAT 

replaced

TAT 

without 

dicamba

3

50% of 

Total 

TAT2

TAT 

Replaced

Diflufenzopyr 100% crop safety 91,117 45,559 45,559 77,449 38,725 38,725

Paraquat 

Oxyfluorfen 

Thifensulfuron 

Tribenuron 

Methyl 

Pyraflufen Ethyl 

CarfentrazoneEthyl 

Flumiclorac 

Rimsulfuron

75%

efficacy 

grower 

preference 

crop safety 

carryover

1,593,460 796,730 597,548 1,354,441 677,221 507,915

2,4-D 

Fomesafen 

Fluometuron 

Metolachlor-S 

Prometryn 

PyrithiobacSodium 

Metolachlor

50%

crop safety 

efficacy 

convenience 

resistance

7,071,266 3,535,633 1,767,817 6,010,576 3,005,288 1,502,644

Flumioxazin 

Diuron 25%

crop safety 

convenience 3,570,338 1,785,169 446,292 3,034,787 1,517,394 379,348

Trifluralin 

Pendimethalin 10% convenience 5,068,116 2,534,058 253,406 4,307,899 2,153,949 215,395

Total 3,110,621 2,644,027

1 Unpublished grower survey data (Monsanto, 2012). TAT is only for those active ingredients within each herbicide 

grouping.

2 TAT replaced = TAT x Projected % Replacement x 50%. Monsanto projects dicamba to be conservatively used on 

50% of U.S. cotton acres at market penetration.

3 Peak TAT factors in a reduction of planted acres in 2011 and an increase non-glyphosate use in the west for a net 15% 

decrease in non-glyphosate herbicide use from 2011 levels.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 465 of 946

Table A-43. Projected lbs a.i. for PRE Cotton Herbicides Likely to be Displaced by Dicamba

20111 Peak

Active Ingredients Major Reasons 

for replacement

Projected % 

Replacement

lbs a.i. 50% of 

Total lbs 

ai2

lbs ai 

replaced

lbs ai 

without 

dicamba3

50% of 

Total lbs 

ai2

lbs ai 

replaced

Diflufenzopyr crop safety 100% 3,051 1,526 1,526 2,593 1,297 1,297 

Paraquat 

Oxyfluorfen 

Thifensulfuron 

Tribenuron Methyl 

Pyraflufen Ethyl 

CarfentrazoneEthyl Flumiclorac 

Rimsulfuron

efficacy grower 

preference crop 

safety carryover 75%

 

 641,338 

 

320,669 240,502 545,137 

 

272,569 

 

204,426 

2,4-D 

Fomesafen 

Fluometuron 

Metolachlor-S 

Prometryn 

Pyrithiobac-Sodium 

Metolachlor

crop safety 

efficacy 

convenience 

resistance

50% 3,971,538 1,985,769 992,885 3,375,807 1,687,904 843,952 

Flumioxazin 

Diuron

crop safety 

convenience 25% 1,152,496 576,248 144,062 979,622 489,811 122,453 

Trifluralin 

Pendimethalin convenience 10% 4,289,433 2,144,717 214,472 3,646,018 1,823,009 182,301 

Total 1,593,445 1,354,429 

1 Unpublished grower survey data (Monsanto, 2012). 

2

lbs a.i. replaced = lbs a.i. x Projected % Replacement x 50%. Monsanto projects dicamba to be conservatively used on 50% of U.S. cotton acres at market 

penetration.

3 Peak lb a.i. factors in a reduction of planted acres in 2011 and an increase non-glyphosate use in the west for a net 15% decrease in non-glyphosate herbicide use 

from 2011 levels.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 466 of 946

A.4.2.2. Analysis of Displacement of Other Non-Glyphosate Herbicides by Dicamba Use 

Following Deregulation of DGT Cotton

The commercialization of a cotton product containing dicamba-tolerance will allow for an increase 

in the use of dicamba for weed control in cotton due to the elimination of in-crop (POST segment) 

and preplant (PRE segment) crop safety concerns. While dicamba is presently labeled for preplant 

uses in cotton, this use is currently limited because the application must be made more than 21 days 

prior to planting, in order to address crop safety risks. With crop safety no longer a barrier, farmers 

can incorporate dicamba into their weed management programs because of the advantages it offers 

versus other herbicides. Those advantages will translate into dicamba replacing certain nonglyphosate herbicides currently used preplant and/or postemergent in cotton. In addition, the 

ability to use dicamba to manage existing resistant weeds will reduce the need for multiple residual 

herbicides and/or multiple postemergence herbicides in some situations. This will drive an overall 

reduction in herbicide use in some situations. For example, Monsanto and academics currently 

recommend that farmers with glyphosate-resistant weeds apply a residual product, such as 

flumioxazin, or fomesafen preplant to the crop, followed by fluometuron preemergence, and 

followed by glyphosate plus acetochlor or metolachlor after planting, and then conclude with 

hooded applications of paraquat and/or directed applications of MSMA or diruon to control 

escapes. With the ability of farmers to use dicamba in crop, dicamba would replace the need for 

several of these products, and others currently being used, thus resulting in a shift and replacement 

of herbicide use and applications.

Glyphosate is not expected to be replaced by dicamba in either the PRE or the POST segment. 

Dicamba will primarily be used in combination with glyphosate and this combination will simply 

displace glyphosate combinations with other non-glyphosate herbicides and/or glyphosate herbicide 

used alone. 

A.4.2.2.1. Projected TAT Estimates for Replacement of Currently Used PRE Herbicides by 

Dicamba 

As stated previously, at peak adoption of DGT cotton, dicamba is projected to be used on 

approximately 50% of total cotton planted acres. The 18.5 million TAT for all non-glyphosate PRE 

herbicides used in cotton in 2011 (Table A-37) adjusted for the dicamba use projection of 50% and 

an estimated 15% reduction in non-glyphosate herbicide use resulting in a theoretical maximum of 

7.86 million TAT in the PRE segment that could potentially be displaced by dicamba. The nonglyphosate herbicides most likely to be displacement by dicamba are listed in Table A-42 and include 

active ingredients that can be used for burndown, residual, or residual and burndown control. These 

herbicides were selected because of the advantages dicamba would offer relative to each selected 

herbicide and expected farmer preferences towards dicamba use (see Table A-42 for specific 

advantages for each group of herbicides). A projected percent replacement by dicamba was then 

estimated for each herbicide based on criteria such as lower efficacy, carryover concerns, existing 

resistance, use restrictions, and/or crop safety. Reductions in the use of each herbicide were then 

estimated and herbicides with the same projected percent replacement were grouped. In the case of 

the PRE herbicides, the groupings were 100%, 75%, 50%, 25% or 10%. Applying the estimated 

percent reductions to the TAT for 2011 provided an estimate for the number of treated acres (TAT) 

that dicamba would replace at peak use of dicamba in DGT cotton. Based on these assumptions, it 

can be projected that dicamba would replace an estimated 2.6 million non-glyphosate PRE herbicide 

TAT at peak use of dicamba (Table A-42). Therefore, dicamba could be expected to conservatively 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 467 of 946

replace approximately 34% of the projected TAT for all non-glyphosate herbicides used in PRE 

application timing at peak dicamba use, based on the 50% of total planted cotton acres where 

dicamba is projected to be used (7.88 million TAT). 

A.4.2.2.2. Projected TAT Estimates for Replacement of Currently Used POST Herbicides 

by Dicamba 

As stated previously, a high-end estimate of dicamba use on cotton is 50% of total cotton acres at 

peak use in DGT cotton. The projected 11 million TAT for all non-glyphosate POST herbicides 

used in cotton at peak use of dicamba (Table A-39) adjusted for the dicamba use projection of 50% 

and an estimated 15% reduction in non-glyphosate herbicide use results in a theoretical maximum of 

4.68 million TAT that could potentially be displaced by dicamba. The non-glyphosate herbicides 

most likely to be displaced by dicamba are listed in Table A-44 and include active ingredients that 

can be used for burndown, residual, or residual and burndown control. These herbicides were 

selected because of the advantages dicamba would offer relative to each selected herbicide and 

expected farmer preferences towards dicamba use (see Table A-44 for specific advantages). A 

projected percent replacement was then estimated for each herbicide based on criteria such as lower 

efficacy, carryover concerns, existing resistance, use restrictions, and/or crop safety. Reductions in 

use of each herbicide were then estimated and herbicides with the same projected percent 

replacement were grouped. In the case of the POST herbicides, the groupings were 75%, 50%, or 

10%. Applying the estimated percent reductions to the TAT for 2011 provided an estimate for the 

number of total acres treated (TAT) that dicamba would replace at peak use of dicamba in DGT 

cotton. Based on these assumptions, it can be projected that dicamba would replace an estimated 

1.75 million non-glyphosate herbicide TAT at peak use of dicamba. Therefore, dicamba could be 

expected to conservatively replace approximately 37% of the projected TAT for all non-glyphosate 

herbicides used in POST application timing at peak dicamba use, based upon the above assumption 

that dicamba will only be used on 50% of total planted cotton acres (4.68 million TAT)

.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 468 of 946

Table A-44. Projected Total Acres Treated for POST Cotton Herbicides Likely to be Displaced by Dicamba

20111 Peak

Active ingredient 

type

% Replacement Reasons for 

replacement

2011 TAT 50% of 

Total 

TAT2

TAT 

replaced

TAT 

without 

dicamba

50% of 

Total 

TAT2

TAT 

Replaced

Prometryn 

Flumioxazin, 

Trifloxysulfuron 

Paraquat 

Fomesafen 

Carfentrazone-Ethyl 

Pendimethalin 

Trifluralin

75%

crop safety 

convenience 

efficacy

 

2,962,625 

 

1,481,313 

 

1,110,984 

 

2,518,231 

 

1,259,116 944,337 

Pyrithiobac-Sodium 

MSMA 

Fluometuron 

Linuron 50%

crop safety 

convenience 

efficacy 

resistance

 

2,890,794 

 

1,445,397 

 

722,699 

 

2,457,175 

 

1,228,587 614,294 

Metolachlor-S 

Acetochlor 

Diruron 

Metolachlor 10% crop safety 

efficacy

 

4,503,927 

 

2,251,964 

 

225,196 

 

3,828,338 

 

1,914,169 191,417 

Total

2,058,879 1,750,047 

1 Unpublished grower survey data (Monsanto, 2012). TAT is only for those active ingredients within each herbicide grouping.

2 TAT replaced = TAT x Projected % Replacement x 50%. Monsanto projects dicamba to be conservatively used on 50% of U.S. cotton acres at market penetration.

3 Peak TAT factors in a reduction of planted acres in 2011 and an increase non-glyphosate use in the west for a net 15% decrease in non-glyphosate herbicide use from 

2011 levels.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 469 of 946

A.4.2.2.3. Projected Total Pound Estimates for Replacement of Currently Used Herbicides 

by Dicamba 

The projected total pounds of herbicides in each application segment (PRE and POST) that would 

be replaced by dicamba were determined using the same methodology and data source as that used 

in the TAT analysis described above. Based on this analysis, Monsanto projects that dicamba would 

replace an estimated 1.35 million pounds of PRE non-glyphosate herbicides and 0.5 million pounds 

of POST non-glyphosate herbicides at peak market penetration (Table A-43 and Table A-45, 

respectively).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 470 of 946

Table A-45. Projected lbs a.i. for POST Cotton Herbicides Likely to be Displaced by Dicamba

20111 Peak

Active 

Ingredients

Major 

Reasons for 

replacement

Projected % 

Replacement

lbs a.i. 50% of 

Total lbs ai2

lbs ai 

replaced

lbs ai 

without 

dicamba3

50% of 

Total lbs 

ai2

lbs ai 

replaced

Prometryn 

Flumioxazin 

Trifloxysulfuron 

Paraquat, 

Fomesafen, 

Carfentrazoneethyl, 

Pendimethalin, 

Trifluralin

crop safety 

convenience 

efficacy

75% 

212,487 

 

106,244 

 

79,683 

 

180,614 

 

90,307 

 

67,730 

Pyrithiobacsodium 

MSMA 

Fluometuron 

Linuron

crop safety 

convenience 

efficacy 

resistance

50% 

1,232,210 

 

616,105 

 

308,053 

 

1,047,379 

 

523,689 

 

261,845 

Metolachlor-s

Acetochlor 

Diruron

Metolachlor

crop safety 

efficacy 10% 4,254,867 2,127,434 212,743 

 

3,616,637 

 

1,808,318 

 

180,832 

Total 

600,478 

 

510,407 

1 Unpublished grower survey data (Monsanto, 2012). 

2

lbs a.i. replaced = lbs a.i. x Projected % Replacement x 50%. Monsanto projects dicamba to be conservatively used on 50% of U.S. cotton acres at market 

penetration.

3 Peak lb a.i. factors in a reduction of planted acres in 2011 and an increase non-glyphosate use in the west for a net 15% decrease in non-glyphosate herbicide use 

from 2011 levels.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 471 of 946

A.4.3. Net Impact of DGT Cotton on Overall Herbicide Use

Estimates of the net impact of DGT cotton on future total acres treated with dicamba and total 

pounds of active ingredients deployed are presented in Table A-46. At projected peak penetration 

of DGT cotton, an increase in both total acres treated and total pounds of dicamba herbicide active 

ingredient applied is projected; however estimated increases are 16% or less of the total herbicide 

use projections (16% for TAT and 12% of total pounds of active ingredient) if DGT cotton is not 

commercialized (Table A-46). In addition, this analysis demonstrates the following two key 

conclusions:

(1) The overall use of non-glyphosate herbicides in cotton production has grown since 

2009. While the overall growth in non-glyphosate herbicides is expected to decrease at the 

time of peak use of dicamba in DGT cotton, due to a reduction in cotton plantings, there 

will be a growth in non-glyphosate herbicide use, particularly in the western cotton markets. 

The current and projected growth is due in large part to the adoption of best management 

practices as recommended by public and private sector weed scientists and the development 

and spread of weed resistance. This increase in non-glyphosate herbicide use will occur even 

in the absence of DGT cotton, and 

(2) When a DGT cotton system is available, dicamba would displace a significant amount of 

non-glyphosate herbicides used for weed management. Our analysis conservatively projects 

that on acres where DGT cotton is planted and dicamba is used, dicamba will replace 

approximately 34% of the projected PRE non-glyphosate herbicide TAT and 37% of the 

projected POST non-glyphosate herbicide TAT. Based on expectations by Monsanto and 

academic weed scientists, farmers will continue to implement diversified weed management 

programs that utilize multiple herbicide modes-of-action, and dicamba will be an important 

weed management tool in future cotton production. 

The anticipated deregulation and subsequent commercialization of DGT cotton will not alter the 

number of cultivated cotton acres or the geographical areas where cotton is cultivated in the U.S. 

Consequently, DGT cotton will be grown on land that is already highly managed for agricultural 

crop production and where herbicides are widely used today. As described previously, the 

commercialization of DGT cotton will result in a slight increase in herbicide use (treated acres and 

pounds of dicamba) on those acres where it is planted and the grower chooses to use dicamba in 

their weed management program. However, the anticipated increase in dicamba relative to overall 

herbicide use in cotton production is relatively low, contributing less than 16% to the overall 

herbicide use in glyphosate-tolerant cotton production.

While an increase in overall herbicide use in cotton growing areas is projected for the 

commercialization of DGT cotton, assuming growers adopt recommended weed management 

practices, these practices provide numerous economic and environmental benefits which are detailed 

in this Environmental Report and Appendices B, C, and F thereto, and summarized below.

 Effective tool for sustainable management of glyphosate-resistant weeds; 

 Mitigate the potential for development of weed resistance for all classes of cotton herbicides; 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 472 of 946

 Improve the consistency of control over hard-to-control weeds, thereby reducing the 

potential for new resistant biotypes to develop;

 Increase application flexibility; 

 Preserve the benefits of the glyphosate-tolerant weed control system; and

 Preserve the many environmental and economic benefits of conservation tillage. 

Furthermore, the projected increase in the amount of dicamba used in cotton production is not 

expected to result in adverse impacts to human health or the environment. The EPA regulates 

pesticide use and is required under FIFRA to reach a conclusion of no unreasonable adverse effects 

to human health and the environment before any application of dicamba can be made on DGT 

cotton (see Appendices E and F to this Environmental Report). Monsanto has submitted an 

application to EPA to approve the use of dicamba on DGT cotton. EPA concluded in the dicamba 

Reregistration Eligibility Decision (RED) document that all then-registered uses of dicamba can be 

used without resulting in unreasonable adverse effects when used according to the approved legal 

label (U.S. EPA, 2009). Because the use pattern for dicamba on DGT cotton is consistent with the 

use patterns and assumptions on herbicide use intensity evaluated in the RED, any projected 

increase in dicamba use related to the commercialization of DGT cotton is not expected to result in 

potential adverse impacts to the human health or the environment, and EPA is expected to 

reconfirm dicamba’s safety as part of its review of the Monsanto application.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 473 of 946

Table A-46. Net Impact of DGT Cotton on Overall Herbicide Use

Projected at Peak planting of DGT 

Cotton

With DGT Cotton

Total Acres 

Treated (TAT) 

(000 acres / year)

Total lbs a.i. 

(000 lbs a.i. 

/year) 

Projected increase in dicamba use 10,7821

 

5,2252

PRE herbicides replaced by dicamba 2,6443

 

1,3544

POST herbicides replaced by dicamba 1,7505

 

5106

Net Change with introduction of DGT 

Cotton 6,388 

 

3,361 

Without DGT Cotton7

Total - non-glyphosate 25,118 

 

14,804 

Total - glyphosate 16,034 

 

14,188 

Total - non-glyphosate plus glyphosate 41,152 

 

28,992

Dicamba increase with DGT cotton as % of 

herbicide use in absence of DGT cotton 16% 12%

1 Table A-40 

2 Table A-41

3 Table A-42 

4 Table A-43 

5 Table A-44

6 Table A-45

7 Totals based upon 15% overall reduction in TAT and lbs ai relative to 2011 levels.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 474 of 946

A.4.4. Comparative Analysis of Dicamba and Alternative Cotton Herbicides

A.4.4.1. Background

Dicamba use in combination with glyphosate and glufosinate in cotton that is tolerant of all three 

herbicides offers an attractive opportunity for cotton farmers to preserve the benefits that glyphosate 

offers while addressing the problem of glyphosate-resistant weeds. Dicamba’s risk profile offers key 

improvements relative to the alternative cotton herbicide a.i.’s. In the following section, a 

comparative analysis of dicamba to the alternative cotton herbicide a.i.’s is presented. 

Table A-47 lists the most-widely used cotton herbicide products. Based on 2011 market data, the 

a.i.’s listed in Table A-47 account for 46.2 million treated acres or 99.7% of the total herbicide-treated 

cotton acres. Table A-47 also summarizes key information about the alternative herbicide products 

that are evaluated in this petition, e.g., signal word, re-entry interval, use rates, and label warnings or 

special directions. Table A-48 lists further information about the herbicidal a.i.’s used in cotton, such 

as the registration date, registration review status, RED date, where the tolerance information can be 

found, whether it is a reduced risk pesticide, and whether it is a restricted use pesticide. 

 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 475 of 946

Table A-47. Dicamba and Alternative Registered Cotton Herbicides

Representative 

Brand

(EPA Reg. No.)

Active 

Ingredient

2011 use area 

3

For a.i.

(K acres / %) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicati

on)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special Directions

Clarity (7969-137) Dicamba 855 / 1.8 Caution 4.0 lb a.e./gal 24 hr 1.0 1 2.0 1 Known to leach; 50-foot buffer to wells; 

Runoff advisory; Drift advisory; Statespecific limitations; Soil type limitations; 

Maximum crop rotation interval 3 – 6 

months.

Ignite (264-829) Glufosinate 

ammonium

1,297 / 2.8 Warning 2.34 lb/gal 12 hr 0.79 1.59 Toxic to vascular plants; May have runoff 

potential; Drift advisory; 70-day cotton 

PHI; Little or no activity in soil; Not in 

Hawaii or S. Florida.

Roundup 

WeatherMAX 

(524-537) 

Glyphosate 23,345 / 50.4 Caution 4.5 lb a.e./gal 4 hr 3.71 5.96 Weed resistance advisory; Drift advisory; 

7-day cotton PHI.

Treflan HFP 

(62719-250)

Trifluralin 4,098 / 8.8 Caution 4.0 lb/gal 12 hr 2 2 Extremely toxic to freshwater, estuarine, 

and marine fish and invertebrates; Some 

crops have long rotational interval (18 - 20 

mos.); 90-day cotton PHI.

Direx 4L (352-678) Diuron 2,110 / 4.6 Caution 4 lb/gal 12 hr 1.6 2.2 Drift Advisory; Crop rotation intervals of 

12 months common; State-specific 

limitations; Soil type limitations; Do not

feed treated foliage to livestock.

Prowl 3.3 EC Pendimethali

n

2,010 / 4.3 Caution 3.3 lb/gal 24 hr 2 2 Toxic to fish; Endangered plant species 

buffer required; Drift and runoff may be 

hazardous to aquatic organisms; Long (14 -

24 mos) crop rotation intervals for some 

crops; 60-day cotton PHI; State-specific 

limitation; Soil-type limitations; Do not 

feed treated foliage to livestock.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 476 of 946

Representative 

Brand

(EPA Reg. No.)

Active 

Ingredient

2011 use area 

3

For a.i.

(K acres / %) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicati

on)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special Directions

Valor SX (59639-

99) 

Flumioxazin 1,835 / 4.0 Caution 0.51 lb/lb 12 hr 0.06 0.13 Toxic to non-target plants & aquatic 

invertebrates; Runoff advisory; 40-foot 

aerial buffer to adjacent crops or water 

bodies; 12-month rotation interval 

common; Cotton injury possible; Do not 

feed treated foliage to livestock; 60-day 

cotton PHI.

Staple (352-576) Pyrithiobacsodium1,689 / 3.6 Warning 0.85 lb/lb 24 hr 0.1 0.13 Highly toxic to non-target plants; Drift 

warnings; Cotton injury possible; Weed 

resistance advisory; 60-day cotton PHI; 

State-specific limitations (Staple LX); 10 –

12 month rotation intervals.

Staple LX (352-

613)

PyrithiobacsodiumCaution 3.2 lb/gal 4 hr 0.1 0.13

Dual Magnum 

(100-816)

SMetolachlor1,492 / 3.2 Caution 7.62 lb/gal 24 hr 1.27 2.48 Potential to leach; Potential for runoff; 

Ground & surface water advisory; State 

specific limitations; Soil type limitations;

Swath adjustment 300 - 400 ft to avoid 

non-target plant injury; 80- to 100-day 

cotton PHI; Do not feed treated foliage to 

livestock.

MSMA 6 Plus 

(19713-42) 

Monosodium 

Metharsonate

1,451 / 3.1 Caution 6 lb/gal 12 hr 1.88 3.75 50-foot buffer around all permanent water 

bodies; Drift warning about adjacent crops 

and sensitive areas; State specific 

limitations; No preplant cotton treatment; 

Do not feed treated foliage to livestock.

Barage HF (5905-

529)

2,4-D 

Ethylhexyl 

Ester (EHE)

1.421 / 3.1 Caution 4.7 lb a.e./gal 12 hr 2.35 2 4.7 2 Toxic to aquatic invertebrates; Drift may 

adversely affect non-target plants or 

invertebrates; Groundwater advisory; 

Weed resistant biotypes known; Do not 

spray if wind above 15 mph.

Weedar 64 (71368-

1)

2,4-D 

Dimethylami

ne Salt

(DMA)

[see 2,4-D 

total above]

Danger 3.8 lb a.e./gal 48 hr 1.9 2 3.8 2 May be toxic to fish & aquatic invert; May 

result in groundwater contamination; Drift 

warning; Do not apply if wind above 15 

mph; Apply only when sensitive areas or 

plants are not with 250 feet downwind.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 477 of 946

Representative 

Brand

(EPA Reg. No.)

Active 

Ingredient

2011 use area 

3

For a.i.

(K acres / %) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicati

on)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special Directions

Reflex (100-993) Fomesafensodium1,415 / 3.1 Danger 2.0 lb a.e./gal 24hr 0.375 0.375 May leach; Groundwater advisory; Some 

long rotation intervals (up to 18 mos.); 

Cotton injury warning; Weed resistance 

advisory; State-specific limitations; Soil 

type limitations; 70-day cotton PHI

Gramoxone Inteon 

(100-1217)

Paraquat 1,078 / 2.3 Danger 2.0 lb 

cation/gal

12 hr 1 3 Restricted Use Pesticide due to acute 

toxicity; May be fatal if swallowed or 

inhaled; Toxic to wildlife; Damage / 

toxicity to non-target crops / plants; Drift 

advisory; Cotton injury possible; Do not 

feed treated foliage to livestock; 3-day 

cotton PHI.

Cotoran (66622-

181)

Fluometuron 786 / 1.8 Caution 4 lb/gal 24 hr 2 3 Known to leach; May result in 

groundwater contamination; Weed 

resistance advisory; Avoid drift to sensitive 

areas; 12-month rotation interval for many 

crops; State-specific limitations; Soil type 

limitations; Do not feed treated foliage to 

livestock; 60-day cotton PHI.

Caparol 4L (100-

620)

Prometryn 867 / 1.9 Caution 4 lb/gal 24 hr 2.4 6 Drift and runoff may be hazardous to 

aquatic organisms; 400 ft upwind swath 

adjustment for sensitive plants; Weed 

resistance advisory; Crop injury possible; 

Soil type limitations; State-specific 

limitations; Do not feed treated foliage to 

livestock.

Envoke (100-1132) Trifloxysulfur

on-sodium

423 / 0.9 Caution 0.75 lb / lb 12 0.012 0.019 Toxic to vascular plants; Ground water 

advisory; Weed resistance advisory; Long 

rotational intervals (12 -22 mos, some 

zones); 60-day cotton PHI; 25-foot buffer 

around treated areas recommended; State 

specific limitations; Soil type limitations.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 478 of 946

Representative 

Brand

(EPA Reg. No.)

Active 

Ingredient

2011 use area 

3

For a.i.

(K acres / %) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicati

on)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special Directions

Aim EW (279-

3242)

carfentrazone 

ethyl

89/0.16 Caution 1.9 lb/gal 12 hr 0.025 0.124 Carfentrazone-ethyl is very toxic to algae 

and moderately toxic to fish. Do not allow 

spray solution to contact cotton foliage, 

green stem tissue, or blooms.

Resolve DF (352-

556)

rimsulfuron 11/0.02 Caution granule 4 hr Not 

labeled 

for 

Cotton

0.03 Do not apply preemergence to coarse 

textured soils (sand, loamy sand, or sandy 

loam) with less than 1% organic matter. 

Adequate soil moisture is required for 

optimum activity. Long rotational 

restrictions up to 10 months. Crop injury 

may occur following application if there is 

prolonged cold weather and/or wet soils.

Treaty (71368-74) thifensulfuro

n methyl

81/0.15 Warning granule 12 hr 0.02 Pre-plant 

burn down 

in 

cotton

Causes substantial but temporary eye 

injury. Do not get in eyes or on clothing. 

Do not graze or feed forage or hay from 

treated areas to livestock. Weed control 

may be reduced if rainfall or snowfall 

occurs soon after application. 

Victory (71368-75) tribenuron 

methyl

70/0.13 Caution granule 12 hr 0.0125 Pre-plant 

burn down 

in 

cotton

Weed control in areas of thin crop stand or 

seedling skips may not be satisfactory. 

Weed control may be reduced if rainfall or 

snowfall occurs soon after application. Do 

not apply later than 14 days before planting 

cotton. Do not graze or feed associated by 

products for 60 days after application.

ET Herbicide 

(71711-7

Pyraflufen 

ethyl

56/0.1 Danger 0.208 lb/gal 12 hr 0.003 0.013 This pesticide is toxic to fish and aquatic 

invertebrates. Allow a minimum of 30 

days between applications for use on 

cotton. Apply to cotton having less than 3 

inches of stem bark using hooded ground 

equipment only. Avoid contact with 

desirable vegetation.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 479 of 946

Representative 

Brand

(EPA Reg. No.)

Active 

Ingredient

2011 use area 

3

For a.i.

(K acres / %) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicati

on)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special Directions

Goal 2XL (62719-

424)

oxyfluorfen 190/0.34 Warning 2 lb/gal 24 hr 0.5 1 This product is toxic to aquatic 

invertebrates and wildlife. Do not graze or 

harvest plants from treated areas for feed 

or forage. Treated soil must be thoroughly 

mixed to a depth of 4 inches after harvest 

prior to planting a rotational crop. Care 

must be taken to avoid spray contact with 

cotton leaves. Do not apply to cotton less 

than 6 inches tall or severe crop injury will 

result.

Resource (59639-

82)

flumiclorac 

pentyl ester

15/0.03 Warning 0.86 lb/gal 12 hr 0.05 0.094 Causes substantial but temporary eye 

injury. This product is toxic to shrimp. 

Keep out of lakes, ponds, and streams. Do 

not graze animals on green forage or use as 

feed fewer than 28 days after application.

1 Dicamba rates cited are those proposed for use on DGT cotton.

2 2,4-D products are not labeled for cotton treatments. Preplant treatments, more than 29 days before planting, are used for burndown weed control using the 

Fallow portion of the label. 

3 Monsanto private market survey data. The data shown are for the cotton acres to which the relevant active ingredient was applied in 2011, and the percentage 

of total treated acres this constitutes. A treated acre is application of one active ingredient once. Multiple active ingredients or multiple applications results in 

total treated acres that exceed total planted cotton acres. No entry is shown for products containing more than one active ingredient, since these acres are 

counted in the single active ingredient rows.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 480 of 946

Table A-48. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide Products

Active Ingredient First 

Registered

Registration 

Review

Status 1

RED 

Date

Max. Cotton 

lb/a (single 

application) 2

Max. Cotton 

lb/a (season) 2

Tolerances 40 

CFR 180.

EPA 

Reduced 

Risk

Classification

Restricted Use

dicamba-diglycolamine 

salt

2-Feb-56 unsched. 2006 1.03 2.03 227 N N

Glufosinateammonium

Glufosinateammonium

29-May-91 2008 N/A 0.79 1.59 473 Yes

Glyphosate (salts) Glyphosate 

(salts) 7-Sept-88 2009 09/23/2009 3.71 5.96 364 Yes

Herbicide a.i.s Applied Primarily at a PE Timing

2,4-D EHE (esters)4

3-Jun-52 2013 2005

2.0 5 4.0 5

142 N N

2,4-D DMA (salts)4

2.0 5 4.0 5

flumiclorac pentyl 23-Mar-94 2009 N/A 0.05 0.094 477 Yes No

S-metolachlor 18-May-83 2016 12/01/1994 1.27 2.48 368 Yes No

oxyfluorfen 17-May-79 2015 10/01/2002 0.5 1 381 No No

pyraflufen ethyl 27-Sept-02 2014 N/A 0.003 0.013 585 No No

rimsulfuron 20-Sept-89 2012 N/A Not labeled for 

cotton

0.03 478 No No

thifensulfuron methyl 25-Apr-86 2011 N/A 0.02 N/A 439 No No

tribenuron methyl 22-May-89 2011 N/A 0.0125 N/A 451 No No

Herbicide a.i.s Applied at both PE and POE Timings

carfentrazone ethyl 02-Aug-95 2011 N/A 0.025 0.124 515 Yes No

fluometuron 28-May-74 Unsched. 09/28/2005 229 No No

fomesafen sodium 10-Apr-87 2007 N/A 0.375 0.375 433 No No

paraquat dichloride 08-Jan-80 2011 08/01/1997 1 3 205 No Yes

Prometryn 19-Aug-74 2013 1996 2.4 5.95 222 N N

Pyrithiobac-Sodium 29-Jun-95 docket ‘11 NA 0.1 0.13 487 N N

Herbicide a.i.s Applied Primarily at a POE Timing

flumioxazin 01-Aug-96 2011 N/A 0.06 0.13 568 No No

MSMA 25-Dec-63 2013 2006 corr 

2009

1.88 3.75 289 N N

pendimethalin 20-Mar-75 2012 04/01/1997 2 2 361 No No

trifloxysulfuron-sodium 29-Jun-03 2013 NA 0.012 0.019 591 N N
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 481 of 946

trifluralin 04-Dec-68 2012 09/01/1995 2 2 207 No No

1 Registration Review Status: year docket is scheduled to open, unless unscheduled. FWP = Final Work Plan stage. If docket is open, “docket XX” = year opened.

2 Rates for dicamba, 2,4-D, fomesafen, and glyphosate are expressed as acid equivalents. All others are on an a.i. basis, as stated, except paraquat is on a cation basis. 

Regional or soil type limitations may lower this rate.

3 Maximum treatment rates for the proposed dicamba label on DGT cotton.

4 For the 2,4-D ester group, the ethylhexyl ester (EHE) is taken as representative. For the salt group, the dimethylamine (DMA) salt is taken as representative.

5 Rates taken from Master 2,4-D Label (http://www.24d.org/masterlabel/default.aspx) for Fallow application. There are no specific cotton treatment directions. Fallow 

application must precede planting by 29 days or more.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 482 of 946

A.4.4.2. Alternative Registered Herbicides – Comparative Analysis

A detailed comparative analysis of the risk profile for glufosinate is not included here because the 

introduction of DGT cotton will not change the use of glufosinate in cotton. However, the data for 

glufosinate is included in the comparisons of cotton herbicides. 

Dicamba’s risk profile offers key improvements relative to the alternative cotton herbicide a.i.’s. In 

the following section, an analysis comparing dicamba to the alternative cotton herbicide a.i.’s is 

presented. Tables A-49 through A-54 include an analysis of risks to human health, aquatic 

organisms, and potential for leaching to groundwater. A variety of chemical-specific public data 

sources were used to compile this comparison; those sources are listed below in “Chemical-Specific 

References”. Glufosinate and glyphosate were not considered valid comparators, because Monsanto 

will recommend their use as part of an integrated pest management system. To summarize the 

findings, a scoring procedure was applied to the data for each a.i. to assign one of three potential risk 

scores for that risk category:

 A Black Circle represents a relatively higher risk among the alternatives considered for that 

general risk parameter.

 A Half Circle represents a intermediate risk among the alternatives considered. 

 A White Circle represents a reduced risk among the alternatives considered.

In order for a pesticide (herbicide) to be registered by EPA the U.S. EPA must conclude that the 

herbicide, when used according to the label, does not pose an unreasonable adverse effect to humans 

or the environment; in order to establish a tolerance for the use of an herbicide on a food or feed 

crop, EPA must find there is a reasonable certainty of no harm to human health from nonoccupational (food, water and residential/recreational) exposures to the herbicide. Consequently, all 

alternative herbicides used in cotton production, including those discussed below, can be used safely, 

and do not pose an unreasonable risk to humans or the environment. Therefore, a Black Circle in 

this evaluation scheme does not mean that the risk parameters are considered to be unacceptable, but 

rather that in comparison with this set of herbicide active ingredients, the herbicides associated with a 

Black Circle have a higher relative risk in that particular concern than those with a White Circle or a 

Half Circle. Conversely, the herbicides with a White Circle indicate a reduced risk in a particular 

category compared to the other herbicides considered in this analysis. 

In some instances, such as those mentioned below, dicamba offers a reduction in risk potential (i.e., 

hazard) compared to some alternative herbicides in the same risk category (e.g., aquatic animal risk). 

In other instances dicamba presents a similar risk potential compared to some alternatives. In a few 

cases, dicamba presents a greater risk potential compared to some alternatives. This comparative 

analysis serves to demonstrate that the use of dicamba on DGT cotton is unlikely to result in a 

significant impact/risk to human health or the environment compared to current herbicide 

agronomic practices and in some instances its use may impart additional benefits as described below. 

A.4.4.2.1. Risks to Human Health

Cotton is grown for its lint and only the by-products are used as food and feed. Further, the 

processed commodities from cotton production, such as oil, do not contain significant herbicide 

residues (Maher and Foster). Because cotton production does not significantly contribute to human 

or animal dietary risk, a detailed comparison of dietary exposure was not included in this analysis. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 483 of 946

Instead, this analysis is focused on risks to workers, applicators, and potential exposure to pesticides 

via drinking water. 

Table A-49 provides information concerning human health parameters for each alternative a.i. These 

include:

 Acute Toxicity Categories for the a.i.;93

 The acute population adjusted dose, aPAD; and

 An Acute Toxicity Score (described below).

The Acute Toxicity Score was created based on the following criteria: White Circle means no 

category I findings, not a skin sensitizer, and aPAD ≥ 0.1 mg/kg/day or not needed. Half Circle 

means one category I acute toxicity finding, a skin sensitizer, or aPAD < 0.1. Black Circle means two 

or more category I acute toxicity findings, a skin sensitizer, or aPAD < 0.1. 

Acute Risk: As shown in Table A-26, dicamba acid has Category II findings for eye and skin 

irritation, but once the acid is neutralized to form the DGA or other salt forms used in formulations, 

all acute Categories are III or IV. The acute population adjusted dose (aPAD) is the EPA's 

maximum acceptable acute exposure level of a substance. The aPAD exposure level is specific for 

each pesticide and is usually experimentally derived from animal studies. Animals (typically rats) are 

dosed with varying amounts of the substance in question, and the largest dose at which no effects are 

observed is identified. This dose level is combined with uncertainty and/or “safety” factors to make 

up the aPAD. The acute population adjusted dose for dicamba is 1 mg/kg/day. This compares 

favorably against the fourteen alternative herbicides presented in Table A-49. Seven of the fourteen 

herbicides (counting 2,4-D dimethylamine (DMA) salt and 2,4-D ethylhexyl ester (EHE) separately) 

have a greater risk as determined by the Acute Toxicity Score. 2,4-D has a low acute population 

adjusted dose at 0.067 mg/kg/day and is a severe eye irritant, resulting in Black Circle Acute Toxicity 

Score. In addition, paraquat dichloride has a low acute population adjusted dose at 0.0042 

mg/kg/day and is highly toxic via inhalation, resulting in a Black Circle Acute Toxicity Score. This is 

especially relevant considering this new use of dicamba will potentially replace the pre-harvest 

burndown application of paraquat dichloride on cotton and is, therefore, a noteworthy reduction in 

potential risk from acute exposure.

94

 

93 Toxicity Category I is highly toxic and severely irritating; toxicity Category II is moderately toxic and moderately irritating; toxicity 

Category III is slightly toxic and slightly irritating; and toxicity Category IV is practically non-toxic and not an irritant.

94 As discussed in section A.4.4.2, all alternative herbicides used in cotton production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 484 of 946

Table A-49. Human Health Risk Parameters for Acute Exposure to Dicamba and Alternate 

Herbicide Products

1 The standard acute toxicity tests for a pesticide include Oral, Dermal, Inhalation, Eye Irritation, Skin Irritation, and Skin

Sensitization. Results are scored using a I to IV scale, where I if worst and IV is best. The skin sensitization test is scored Yes or 

No. The results of this battery for each a.i. are shown in order. Toxicity Category I is highly toxic and severely irritating; toxicity 

Category II is moderately toxic and moderately irritating; toxicity Category III is slightly toxic and slightly irritating; and toxicity 

Category IV is practically non-toxic and not an irritant.

2 The Acute Population Adjusted Dose (aPAD) as determined by EPA risk assessments. 

3 White Circle means no category I findings, not a skin sensitizer, and aPAD ≥ 0.1 mg/kg/day or not needed. Half Circle means 

one category I acute toxicity finding, a skin sensitizer, or aPAD < 0.1. Black Circle means that two or more of the criteria listed 

for “2” are met. Active Ingredient

Acute (Oral, Dermal, 

Inhalation, Eye Irr., Skin 

Irr., Sens.) 1

aPAD 

mg/kg/day 2

Acute 

Toxicity 

Score 3

dicamba acid /DGA salt 4 III / III / IV / II / II / N; 

III / III / IV / III / III / N 1

glufosinate-ammonium III / III / III / III / IV / N 0.0063 *

glyphosate (salts) IV / IV / ? / II / IV / N;

IV / IV / III / III / IV / N no need *

2,4-D DMA (salts) III / III / IV / I / IV / ? 5

2,4-D EHE (esters) III / III / IV / III / IV / ? 5

flumiclorac pentyl IV / III / IV / II / II / Y no need

S-metolachlor III / III / IV / III / IV / Y 3

oxyfluorfen IV / III / IV / IV / IV / N no need

pyraflufen ethyl IV / III / IV / III / IV / N no need

rimsulfuron IV / IV / IV / III / IV / IV no need

thifensulfuron methyl IV / III / IV / III / IV / N 1.59

tribenuron methyl IV / III / III / II / IV / Y no need

carfentrazone ethyl IV / III / IV / IV / IV / N 5

fluometuron III / III / III / II / II / N 0.1

fomesafen sodium III / II / III / I / II-III / Y no need

paraquat dichloride II / III / I /II / IV / N 0.0042

prometryn III / III / III / III / IV / N 0.12

Pyrithiobac-sodium III / III / IV / II / ? / N no need

flumioxazin IV / III / IV / III / IV / N 0.03

MSMA III / III / III / III / IV / N 0.1

pendimethalin III / IV / IV / III / IV / N no need

Trifloxysulfuron-sodium IV / IV / IV / III / III / N 0.5

trifluralin IV / III / III / III / IV / Y 1

Herbicide A.I.s with Potential Displacement of Postemergent Acres

0.067

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Herbicide A.I.s with Potential Displacement of both Preemergent and 

Postemergent Acres
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 485 of 946

4 Dicamba diglycolamine salt acute toxicity data for Clarity formulation (EPA Reg. No. 7969-137)

5 2,4-D acid and several salt and ester forms are not skin sensitizers. The data for the DMA salt and EHE were considered 

“unacceptable” by EPA when the RED was published.

* Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an 

integrated pest management system.

PE – preemergent

POE – postemergent

 

Table A-50 provides additional information concerning human health parameters for each alternative 

a.i.’s. These include:

 Cancer Classification;

 Cancer risk when quantitative risk assessment is required by EPA;

 Cancer Risk Score (described below); and

 Chronic Risk Score (described below).

The scoring method used for the Cancer Risk Score is based on the EPA cancer classification and the 

quantitative risk where required by EPA. White Circle means favorable cancer classifications, 

including E, “not likely” or “no evidence of.” Half Circle means C or “likely” carcinogens not 

requiring quantitative risk assessment, or those with quantitative risk estimated below EPA’s 1 x 10-6

concern threshold. Black Circle identifies a.i.’s whose cancer risk is above 1 x 10-6. 

The chronic risk score is based on the degree of toxicity represented by the cPAD as follows: A 

White Circle score is cPAD > 0.1, a Half Circle Score is cPAD between 0.1 and 0.01 (0.1 > cPAD > 

0.01), and a Black Circle Score is a cPAD < 0.01.

Cancer Risk: Dicamba is classified as “Not Likely” for human carcinogenicity. Ten of the alternative 

herbicides also have a White Circle for their Cancer Risk Score. However, nine alternative herbicides 

have a greater cancer risk—C or higher classifications—than dicamba, and two of them—

fluometuron and MSMA— have a significantly higher risk as shown by the Black Circle for Cancer 

Risk Score, because the required quantitative risk assessment resulted in a finding that was greater 

than 1 x 10-6. Overall, Monsanto concludes that dicamba has lower potential cancer risk than eleven 

of the alternative herbicide a.i.’s used on cotton, as shown in Table A-50.95

Chronic Risk. Chronic risk can be evaluated by consideration of the chronic population adjusted 

dose (cPAD or the “risk cup”) for an a.i.. Table A-50 tabulates the cPAD for each alternative a.i., 

according to recently published Federal Register Final Rule information. For dicamba and three of 

the alternative herbicides, the cPAD is 0.1 or greater resulting in a White Circle for Chronic Risk 

Score. Eight alternative a.i.’s, have a cPAD between 0.1 and 0.01 resulting in a Half Circle Chronic 

Risk Score. And five of the alternative a.i.’s (2,4-D, tribenuron methyl, fluometuron, fomesafen 

sodium, and paraquat dichloride) have a cPAD of less than 0.01, resulting in a Black Circle Chronic 

 

95 As discussed in section A.4.4.2, all alternative herbicides used in cotton production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 486 of 946

Risk Score. Therefore, dicamba represents a lower potential risk for chronic risk compared to 

thirteen of the alternative a.i.’s.95
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 487 of 946

Table A-50. Human Health Risk Parameters for Chronic Exposure to Dicamba and 

Alternative Herbicides 

1 Cancer Classification, followed by Q1* value, when required

2 Cancer risk is calculated by EPA when quantitative risk assessment is warranted.. It is based on estimated exposure, using the 

potency factor Q1*, as listed in the column to the left. Risk below 1 x 10-6 is considered an acceptable risk threshold. Risk 

above this level is highlighted in red.

3 Cancer Risk Score. White Circle means favorable cancer classifications, including E, “not likely”, or “no evidence of”, Half Circle 

means C or “Likely” carcinogens not requiring quantitative risk assessment, or those with risk below the 1 x 10-6 threshold. 

Black Circle identifies a.i.s whose cancer risk is above 1 x 10 -6.

4 The chronic population adjusted dose (cPAD) as determined by EPA risk assessments. 

5 The chronic risk score is based on cPAD, a white circle score is cPAD > 0.1, a Half Circle Score is cPAD between 0.1 and 0.01

(0.1 > cPAD > 0.01), and a Black Circle Score is a cPAD < 0.01

6 Inorganic arsenic is a degradate of MSMA and is considered a human carcinogen.

*Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an 

integrated pest management system.

Active Ingredient

Cancer 

Classification 1 Cancer Risk2

 Cancer 

Risk Score 3

cPAD 

mg/kg/day4

Chronic Risk 

Score 5

dicamba acid /DGA salt 4 not likely NA 0.45

glufosinate-ammonium no evid. of NA * 0.006 *

glyphosate (salts) E NA * 1.75 *

2,4-D DMA (salts)

2,4-D EHE (esters)

flumiclorac pentyl No evidence NA 1

S-metolachlor C (no Q1*) NA 0.1

oxyfluorfen C (7.32x10- 2) 3.8 x 10- 7 0.03

pyraflufen ethyl C (3.32 x 10- 2) 2.6×10-6 0.2

rimsulfuron not likely NA 0.118

thifensulfuron methyl No evidence NA 0.043

tribenuron methyl C (no Q1*) NA 0.008

carfentrazone ethyl not likely NA 0.03

fluometuron C (1.8x10- 2) 1.2 x 10- 5 0.0055

fomesafen sodium not likely NA 0.0025

paraquat dichloride E NA 0.0045

prometryn E NA 0.04

Pyrithiobac-sodium C (1x10- 3) 2 x 10- 7 0.58

flumioxazin not likely NA 0.02

MSMA

carcinogenic 

metab.6 1x10- 4 to 4x10- 4 0.03

pendimethalin C (no Q1*) NA 0.03

Trifloxysulfuron-sodium not likely NA 0.237

trifluralin C (5.8x10- 3) 1.6 x 10- 7 0.024

Table 6. Human Health Risk Parameters for Chronic Exposure to Dicamba and Alternate Herbicides

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

Herbicide A.I.s with Potential Displacement of Postemergent Acres

D (not 

classifiable) NA 0.005

Table Table A-50A-43. Human Health Risk Parameters for Chronic Exposure to Dicamba and Alternate 

Herbicides
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 488 of 946

A.4.4.2.2. Risk to Fish and Aquatic Invertebrates

Table A-51 provides information about the hazards, exposures, and risks of dicamba DGA salt and 

each of the twenty-two alternative a.i.’s used in cotton to fish and aquatic invertebrates. For this 

analysis, 2,4-D DMA salt and 2,4-D EHE are considered separately, since they have substantially 

different water solubility. The criteria in this category include:

 Estimated environmental concentrations (EECs) of each of the seventeen (17) a.i.’s in surface 

water using the 4-day EEC as described by the Generic Estimated Environmental 

Concentration (GENEEC)96 model. This model is used by EPA to estimate a pesticide’s 

environmental exposure to aquatic ecosystems based on parameters including application 

rate, degradation rate, soil-binding properties, etc. 

 LC50 endpoints from acute fish toxicity studies or EC50 hazard values from the National Site 

for the USDA Regional IPM Centers Information System. The highest and lowest LC50

values for any reported fish study are listed for each a.i., regardless of species, including both 

fresh and marine species together. The purpose is to define a range of concentrations that 

encompass expected fish-toxic levels. In some cases, study results based on testing end-use 

formulations were generally omitted unless data on the active ingredient was not available, or 

it was likely that formulation components did not influence the study results.

 EC50 or LC50 endpoints from acute aquatic invertebrate studies, as reported from the National 

Site for the USDA Regional IPM Centers Information System. The highest and lowest EC50

or LC50 values for any invertebrate study are listed, regardless of species, including both fresh 

water and marine species together. The purpose is to define a range of concentrations that 

encompass expected aquatic invertebrate-toxic levels. Studies on end-use formulations were 

considered as described above. Results attributable to formulation ingredients, such as 

solvents or surfactants, were sometimes omitted.

 Calculated Risk Quotients (RQs) for aquatic animals, comprised of fish and aquatic 

invertebrates combined together. Rather than calculate a single RQ for each species, 

Monsanto has calculated a range of potential RQs for each a.i., bracketed by the best- and 

worst-case values. The “best” RQ is derived from the ratio of the lowest reported EEC 

concentration divided by the highest LC50 or EC50 for any aquatic animal. Conversely, the 

“worst” RQ is derived from the ratio of the highest EEC concentration divided by the lowest 

LC50 or EC50 for any aquatic animal. The purpose is to define a range of RQs that span and 

describe the risk posed by the alternative herbicide to aquatic animals. The RQs that exceed 

the EPA’s Level of Concern (LOC) of 0.5 are marked in bold red font.

 The Aquatic Fish and Invertebrate Score is a means of summarizing the risk data for aquatic 

animals that is based entirely on the calculated risk quotient. A White Circle means that the 

worst-case RQ estimate < 0.05, which is EPA’s LOC for acute aquatic risk for endangered 

aquatic animals. A Half Circle means that the worst case risk quotient is greater than 0.05 and 

less than 0.5 (0.5 > RQ > 0.05). 0.5 is EPA’s LOC for acute aquatic risk for non-endangered 

 

96 US EPA provides access to GENEEC via a downloadable executable program and users manual at 

http://www.epa.gov/oppefed1/models/water/#geneec2.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 489 of 946

animals. A Black Circle means that the worst-case RQ is greater than 0.5, indicating an acute 

risk for aquatic animals above EPA’s Level of Concern (LOC).

The assessment and comparison summarized in Table A-51 establishes that dicamba poses little acute 

risk to aquatic animals, which is consistent with EFED’s assessment published in the EFED chapter 

in the RED (EPA 2006). The entries that exceed this LOC are those “worst case” values for 2,4-D 

(acid / salt and esters considered separately), flumiclorac pentyl, oxyluorfen, pyraflufen ethyl, 

pendimethalin, and trifluralin. These a.i.’s received a Black Circle for their Aquatic Fish and 

Invertebrate Score, and their RQ’s are highlighted in red bold font. 

Five alternative a.i.’s (S-metolachlor, carfentrazone ethyl, fluometuron, prometryn, and flumioxazin) 

have worst case RQs above 0.05 but less than 0.5 and received a Half Circle for their Aquatic Fish 

and Invertebrate Scores. EPA considers the LOC for aquatic animals that are endangered species to 

be 0.05. The labels for herbicide products that received a Black Circle Aquatic Fish and Invertebrate 

Score and the labels for some of the herbicide products that received a Half-Circle Aquatic Fish and 

Invertebrate Score also bear warning statements for toxicity to fish or invertebrates based on the 

hazard values of those a.i.’s. Therefore, Monsanto concludes that dicamba presents a lower risk

potential to aquatic animals than twelve of the twenty-two alternative herbicidal a.i.’s used on cotton 

as presented in Table A-51.97

 

97 As discussed in section A.4.2.2, all alternative herbicides used in cotton production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 490 of 946

Table A-51. Aquatic Toxicity for Fish and Aquatic Invertebrates from Acute Exposure

1 Dicamba, 2,4-D salts and esters, fomesafen, and glyphosate are expressed on acid equivalent basis. Paraquat is on a cation basis. All 

others are on an a.i. basis as stated. 

2 GENEEC is a surface water model to Estimate Environmental Concentration (EEC) used by US EPA. Further information can be 

found at 

http://www.epa.gov/pesticides/science/models_pg.htm#aquatic.

3 LC50 or EC50 hazard values from http://www.ipmcenters.org/ecotox/index.cfm. Entries are the highest and lowest values provided 

for the a.i. for fish and invertebrates, separately. [10-Apr-2013 download].

4 Risk Quotient is defined as exposure / hazard, both expressed as ppm (mg/L). “Best” means lowest exposure / hazard endpoint. 

“Worst” means highest exposure / hazard endpoint. Entries of 0 mean that the RQ is less than 0.0005 or the data was not available.

5 Aquatic Fish and Invertebrate Score: White Circle means that the worst-case RQ estimate < 0.05. Half Circle means that for the 

worst-case RQ, 0.05 < RQ < 0.5. Black Circle means that the worst-case RQ is greater than 0.5, indicating acute risk for aquatic 

animals.

6 Data for dicamba diglycolamine salt from EFED Chapter for the Dicamba RED. 

Note: As much as possible, LC50 or EC50 hazard values were chosen from tests with the technical a.i. to avoid using hazard endpoints 

that are caused by solvents, surfactants, or other formulation ingredients.

*Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated 

pest management system. Dicamba, 2,4-D salts and esters, fomesafen, and glyphosate are expressed on acid equivalent basis. 

Paraquat is on a cation basis. All others are on an a.i. basis as stated. 

Active Ingredient GENEEC2 

4-day EEC 

Aquatic Fish 

and 

Invertebrate 

Score 5

(ppm) low high low high best worst

dicamba acid /DGA salt6 0.049 > 270 - > 270 - - 0

glufosinate-ammonium 0.022 13.1 > 1000 7.5 668 0 0.003 *

glyphosate (salts) 0.0597 4 5 > 1000 > 10 934 0 0.001 *

2,4-D DMA (salts) 0.087 > 100 524 0.15 103 0.001813 0.580

2,4-D EHE (esters) 0.09 1 8 180 0.054 > 5 0.0005 1.67

flumiclorac pentyl 0.95 1.1 17.4 0.56 3 8 0.025 1.70

S-metolachlor 0.054 3.2 1 7 1.4 2 6 0.002077 0.039

oxyfluorfen 2.55 0.074 0.17 0.069 1000 0.00255 3 7

pyraflufen ethyl 74.14 0.056 9 9 0.043 121 0.612727 1724

rimsulfuron 2.33 110 1000 110 390 0.00233 0.021

thifensulfuron methyl 2.29 100 100 NA NA 0 0.023

tribenuron methyl 2.87 1000 1000 720 720 0.00287 0.004

carfentrazone ethyl 279.89 1.14 2 1.16 9.8 0.00551 0.05

fluometuron 0.107 0.64 6 5 > 1 2 2 0 0.167

fomesafen sodium 0.021 > 163 6030 22.1 397 0 0.001

paraquat dichloride 0.0026 > 1 156 > 1 1 1 0 0.0026

prometryn 0.09 > 1 1 0 1.7 2 1 0 0.052941

Pyrithiobac-sodium 0.0057 > 145 > 1000 > 140 > 910 0 0

flumioxazin 0.0016 2.3 > 21 0.23 5.5 0 0.007

MSMA 0.0498 1 2 323 77.5 173 0 0.00415

pendimethalin 0.013 0.0098 90.4 0.017 1 1 0.0001 1.33

Trifloxysulfuron-sodium 0.00068 > 97 > 104 60.1 > 119 0 0

trifluralin 18.69 0.0084 0.21 0.037 2.2 8.495 8 9

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

Herbicide A.I.s with Potential Displacement of Postemergent Acres

Aquatic Invertebrate 

LC50 or EC5 0

3

 Range 

(ppm) 

Risk Quotient for 

Aquatic Animals 

Range 4

Exposure/Hazard

Fish LC5 0 Range 3 

(ppm) 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 491 of 946

A.4.4.2.3. Risk to Aquatic Plants

Table A-52 provides information about the hazards, exposures, and risks related to aquatic plants for 

dicamba and each of the twenty-two alternative herbicide a.i.’s used on cotton. The data format, 

sources, and methods of Estimated Environmental Concentration (EEC) calculation for aquatic 

plants are identical to those described for aquatic animals (Table A-51). A Level of Concern (LOC) 

value of 1.0 has been used for judging RQ exceedances in the case of aquatic plants, consistent with 

EPA EFED’s normal practices.

 Aquatic Plant Toxicity is based on the hazard values from the National Site for the USDA 

Regional IPM Centers Information System. Table A-52 lists the LC50 and no observed effect 

concentration (NOEC) for each named species. Entries are for the named genus with the 

lowest EC50, and the corresponding NOEC level. .

 The Risk Quotient for Aquatic Plants is defined as EEC / hazard, both expressed as ppm 

(mg/L). RQ Range is determined from the EC50 and the NOEC concentration. A Level of 

Concern (LOC) value of 1.0 has been used for judging RQ exceedance in the case of aquatic 

plants, consistent with EPA EFED’s normal practices. It should be noted that there are 

currently no threatened or endangered non-vascular aquatic plants, and therefore exceedances 

based on non-vascular plants would have no impact for listed species. 

 The Aquatic Plant Score is based entirely on the Risk Quotient for Aquatic Plants. A White 

Circle means that only the high range limit for endangered (listed) aquatic plant species 

exceeds EPA’s LOC of at most 1.0. A Half Circle means that both the RQ range limits for 

endangered (listed) plant species exceed EPA’s LOC of 1.0 for aquatic plant risk. A Black 

Circle means that both the RQ range limits for endangered (listed) plant species exceed EPA's 

LOC by more than 100.

 The assessment and comparison summarized in Table A-52 establishes that dicamba poses 

little acute risk to aquatic plants, which is consistent with EFED’s assessment published in 

the EFED chapter of the RED. Dicamba and two of the alternative herbicide a.i.’s used in 

cotton have RQs with the high range limit for aquatic plant species higher than EPA’s LOC 

of 1.0, while another two do not exceed the LOC of 1.0 even at the high range limit. Seven 

of the alternative herbicides have both the RQ range limits for aquatic plant species higher 

than EPA’s LOC of 1.0. Seven alternative herbicides have both the RQ range limits for 

aquatic species higher than EPA's LOC by more than 100. Dicamba has a lower risk for 

aquatic plant toxicity when compared to fourteen of the alternative herbicides used in cotton. 

Therefore, Monsanto concludes that dicamba offers a lower risk potenail for use on cotton 

with regard to aquatic plant risk.98

 

98 As discussed in section A.4.2.2, all alternative herbicides used in cotton production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 492 of 946

Table A-52. Aquatic Toxicity Parameters for Aquatic Plants for Dicamba and Alternate 

Herbicide Active Ingredients

1 Dicamba, 2,4-D salts and esters, fomesafen, and glyphosate application rates are expressed on acid equivalent basis. Paraquat is on a cation 

basis. All others are on an a.i. basis as stated. 

2 GENEEC is a surface water model to Estimate Environmental Concentration (EEC) used by US EPA. Further information can be found at 

http://www.epa.gov/pesticides/science/models_pg.htm#aquatic

3 NOEC means No Effect Concentration. Entries are for the named genus with the lowest LC50 or EC50, and the corresponding NOEC level. 

LC50 or EC50 and NOEC hazard values from http://www.ipmcenters.org/ecotox/index.cfm . [10-Apr-2013 download]

4 Risk Quotient is defined as EEC / hazard, both expressed as ppm (mg/L). RQ Range is determined from the EC50 or LC50 and the NOEC 

concentration.

5 Data are for dicamba acid from EFED Chapter for the Dicamba RED. No data are available for testing of dicamba DGA salt against aquatic 

plants.

6 Aquatic Plant Score: A White Circle means that only the high range limit is exceeds EPA's LOC of 1.0. A Half Circle means both the RQ 

range limits exceed EPA's LOC of 1.0. A Black Circle means both of the RQ range limits exceed EPA's LOC by more than 100.

Note: As much as possible, LC50 or EC50 hazard values were chosen from tests with the technical a.i. to avoid using hazard endpoints that are 

caused by solvents, surfactants, or other formulation ingredients.

* Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated pest 

management system.

Active Ingredient1 GENEEC2 

4-day EEC 

Aquatic Plants Toxicity 3 

(Most Sensitive Species 

Tested)

LC50 NOEC3

Risk Quotient 

for Aquatic 

Plants 4

Aquatic 

Plant 

Score6

(ppm) Species (ppm) (ppm) RQ Range

dicamba acid /DGA salt 0.049 anabena5 0.06 0.005 0.82-9.8

glufosinate-ammonium 0.022 lemna 1.47 0.8 0.015-0.0275 *

glyphosate (salts) 0.0597 skeletonema 0.34 0.057 0.175-1.05 *

2,4-D DMA (salts) 0.087 skeletonema 0.58 0.27 0.15-0.32

2,4-D EHE (esters) 0.09 skeletonema 0.23 0.094 0.39-0.96

flumiclorac pentyl 0.95 lemna > 0.035 NA >2.7

S-metolachlor 0.054 selenastrum 0.008 0.0015 6.75-36

oxyfluorfen 2.55 selenastrum 0.00029 0.0001 8793-25500

pyraflufen ethyl 74.14 navicula 0.0015 0.00052 49426-142577

rimsulfuron 2.33 lemna 0.0116 0.00009 201-25888

thifensulfuron methyl 2.29 lemna 0.00159 0.00051 1440-4490

tribenuron methyl 2.87 lemna 0.003 0.001 957-2870

carfentrazone ethyl 279.89 lemma 0.006 0.002 46648-139945

fluometuron 0.107 anabena 0.13 0.07 0.82-1.53

fomesafen sodium 0.021 selenastrum 0.092 0.0095 0.23-2.21

paraquat dichloride 0.0026 navicula 0.00055 0.00022 4.73-11.82

prometryn 0.09 navicula 0.001 0.0003 90-300

Pyrithiobac-sodium 0.0057 lemna 0.0009 0.00027 6.33-21.11

Herbicide A.I.s with Potential Displacement of Postemergent Acres

flumioxazin 0.0016 lemna 0.00049 0.00022 3.26-7.27

MSMA 0.0498 selenastrum 5.63 < 0.3 0.009-0.17

pendimethalin 0.013 skeletonema 0.0052 0.0007 2.5-18.57

Trifloxysulfuron-sodium 0.00068 lemna 2.50E-05 2.00E-07 27.2-3400

trifluralin 18.69 navicula 0.0153 0.0046 1221-4063

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 493 of 946

A.4.4.2.4. Groundwater and Leaching

Table A-53 provides information about the soil leaching potential of dicamba and the twenty-two 

alternative herbicide a.i.’s used in cotton. The two aspects of this evaluation are: (1) the properties of 

each substance indicating that it may likely move downward through the soil layers and reach

groundwater; and (2) estimated groundwater concentrations.

Herbicide physico-chemical properties that are associated with downward soil mobility have been 

widely investigated. Persistence in soil (slow degradation) and weak soil binding are common 

predictors of leachability risk. The Groundwater Ubiquity Score (GUS) is an empirical index that 

mathematically combines these two parameters to sort chemicals into categories ranging from 

“extremely low” likelihood of leaching to “very high” likelihood (Gustafson 1989).99 Table A-53 lists 

information about: 

 Soil degradation rate (soil half-life), which quantifies the time for 50% of the initial amount to 

dissipate. The typical values were obtained from the IUPAC Footprint database.100

 Soil mobility constant with regard to organic carbon (Koc), which is the equilibrium 

concentration ratio between soil and pore water, normalized for the organic carbon content 

of the soil. Typical values were obtained from the IUPAC Footprint database.101 

 The GUS index, calculated by the published mathematical formula, using the typical soil halflife and typical Koc values, along with the interpretive category.

 The maximum single application rate in both pounds per acre and in kilograms per hectare 

for dicamba and each alternative herbicide a.i. Potential groundwater concentrations are 

directly related to application rate.

 The IUPAC Footprint database provides a standard estimate of groundwater concentration 

using EPA’s SCI-GROW model and assumes a consistent 1.0 kilogram per hectare 

application. Because these estimates have been calculated in the same way for dicamba and 

the alternative herbicide a.i.’s, they serve as a basis for comparison of leachability.

 The IUPAC Footprint SCI-GROW estimates were adjusted to reflect the proposed labeled 

maximum application rate in cotton by multiplication of the application rate in kilograms per 

hectare.

 In a dietary risk assessment, EPA assumes that a 10 kilogram child consumes 1 liter of water 

per day. Using this standard, the SCI-GROW-estimated groundwater concentrations due to 

the maximum cotton application rate were converted to the potential exposure to a child 

arising from drinking such groundwater, in milligrams of a.i. per kilogram of body weight per 

day. This calculation provides a way to compare potential groundwater concentration to 

toxicity thresholds. The child’s water consumption was chosen over that of an adult because 

 

99 GUS is calculated as GUS = LOG10(soil half-life)*(4-LOG10(Koc)). The interpretation of GUS as a measure of the likelihood of 

leaching is as follows: < 0.1 = Extremely Low (EL); 0.1 – 1.0 = Very Low (VL); 1.1 – 2.0 = Low (L); 2.1 – 3.0 = Moderate (M); 3.1 –

4.0 = High (H); > 4.0 = Very High (VH).

100 The Footprint database, as presented by IUPAC at http://sitem.herts.ac.uk/aeru/iupac/index.htm

101 Values from the Footprint database were not confirmed by comparison to values in U.S. registration documents such as REDs.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 494 of 946

children’s waterborne exposure is greater than that of an adult on a body weight basis, so it 

represents a worst-case assessment.

 The chronic Population Adjusted Dose from Table A-50 is shown for comparison.

 The child’s potential exposure to dicamba and each alternative herbicide a.i. via drinking 

groundwater expressed as a percentage of the cPAD. 

Dicamba’s SCI-GROW-estimated groundwater concentration (0.033 μg/L) is very small, particularly 

in relationship to dicamba’s chronic toxicity reference point (cPAD). Table A-53 shows that a child’s 

potential drinking water exposure to dicamba is calculated to be 0.0008% of the cPAD, where the 

cPAD is considered to be the highest safe chronic exposure level. Dicamba’s estimated child 

exposure level is the 6th lowest among the twenty-two potential alternative a.i.’s for which such a 

value could be calculated in this analysis; data were not available for MSMA (see below). For some 

alternative herbicide a.i.’s, the child’s potential drinking water exposure as a percentage of the 

respective cPAD was calculated to be 100- to 1000-fold higher than that of dicamba. 

Two criteria were evaluated to determine a Groundwater Risk Score as shown in Table A-53. The 

first criterion was the GUS groundwater vulnerability index, indicating whether the a.i.’s physicochemical properties predict downward soil mobility. GUS values above 3.0 are rated as high or very 

high leachability potential, which was chosen as one trigger for groundwater risk. A second criterion 

was the percentage of the cPAD potentially experienced by a child consuming the SCI-GROWestimated groundwater concentration of each a.i. The % exposure above 0.1% of the cPAD was 

chosen as a second trigger for groundwater risk. A.i.’s that met both triggers, i.e., a high or very high 

GUS index and exposures > 0.1% of cPAD, were scored with a Black Circle. An a.i. that met just 

one of these two triggers was scored with a Half Circle. Those a.i.’s that met neither trigger are 

indicated in Table A-53 with a White Circle. 

Monsanto believes that for groundwater risk, dicamba offers a lower risk potential compared to 

thirteen of the alternative herbicide a.i.’s which were shown to have Black Circle or Half Circle 

scores.102 The dietary exposure and groundwater contamination risk could be considered relatively 

greater for MSMA and fluometuron as compared to dicamba, therefore justifying their categorization 

as higher groundwater risk with Black Circle Groundwater Risk scores. Seven alternative herbicide 

a.i.’s have low Groundwater Risk Scores and are marked with White Circles.

 

102 As discussed in section A.4.2.2, all alternative herbicides used in soybean production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 495 of 946

Table A-53. Groundwater and Leaching Parameters for Dicamba and Alternate Active Ingredients

1 Parameters obtained from the Footprint database, as presented by IUPAC http://sitem.herts.ac.uk/aeru/iupac/index.htm or http://pmep.cce.cornell.edu/profiles/extoxnet/index.html

Active Ingredient

Typical 

Soil 

Halflife1

Soil 

Mobility

Koc1

GUS 

Leaching 

Index3 

(Interpre

tation) 2

Maximum 

Cotton 

lb/acre 

(single 

treatment)

3

Maximum 

Cotton 

kg/ha 

(single 

treatment)

3

SCIGROW 

Conc. Est. 

@ 1 

kg/ha 1

SCIGROW 

Conc. Est. 

@ cotton 

Max Rate 

4

Child 

(10 kg) 

consum

ption 

(1L/day)

5

cPAD 

mg/kg/

day 6

Child's 

water 

exposure 

as % 

cPAD 7

Groundwater 

and Leaching 

Score 8 

days (calc) lb/acre kg/ha μg/L μg/L mg/kg

dicamba acid /DGA salt 8 13.4 2.6 (M) 1 1.1 0.0326 0.03586 3.59E-06 0.45 0.0008

glufosinate-ammonium 7.4 600 1.1 (L) 0.79 0.89 0.00982 0.00874 8.74E-07 0.006 0.01457 *

glyphosate (salts) 1 0 1435 0.9 (VL) 2 4.2 0.00535 0.02247 2.25E-06 1.75 0.00013 *

2,4-D DMA (salts) 2.5 2.1 (M) 0.0248 0.05555 5.56E-06 0.005 0.1111

2,4-D EHE (esters) 6 4 1.62 0.0248 0.05555 5.56E-06 0.005 0.1111

flumiclorac pentyl 8 6 3 0 1 (EL) 0.054 0.06048 0.0025 0.00015 1.51E-08 1 1.5E-06

S-metolachlor 9 0 120 1.9 (L) 1.31 1.4672 0.051 0.07483 7.48E-06 0.1 0.00748

oxyfluorfen 4 100,000 0.19 (EL) 0.5 0.56 0.00658 0.00368 3.68E-07 0.03 0.00123

pyraflufen ethyl 4 1949 0.43 (EL) 0.0053 0.005936 0.0023 1.3E-05 1.35E-09 0.2 6.7E-07

rimsulfuron 1 4 50.3 3.23 (H) 0.03 0.0336 0.317 0.01065 1.07E-06 0.118 0.0009

thifensulfuron methyl 4 28.3 1.53 (L) 0.047 0.05264 0.00351 0.00018 1.85E-08 0.043 4.3E-05

tribenuron methyl 0.5 3 5 2.88 (M) 0.047 0.05264 0.135 0.00711 7.11E-07 0.008 0.00888

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

carfentrazone ethyl 1 5 866 0.32 (EL) 0.031 0.03472 5.9E-05 2.1E-06 2.06E-10 0.03 6.9E-07

fluometuron 3 5 175 3.9 (H) 2 2.24 1.04 2.3296 2.33E-04 0.006 4.23564

fomesafen sodium 1067 5 0 4.4 (VH) 0.38 0.4256 0.408 0.17364 1.74E-05 0.003 0.69458

paraquat dichloride 24.3 100000 -0.6 (EL) 1 1.12 0.00535 0.00599 5.99E-07 0.005 0.01332

prometryn 4 9 400 2.3 (M) 2.4 2.688 0.0113 0.03037 3.04E-06 0.04 0.00759

Pyrithiobac-sodium 181 9 5.4 (VH) 0.1 0.112 5.49 0.61488 6.15E-05 0.58 0.0106

Herbicide A.I.s with Potential Displacement of Postemergent Acres

flumioxazin 200 889 1.4 (L) 0.06 0.0672 0.029 0.00195 1.95E-07 0.02 0.00097

MSMA 4 1 - 2.3 (M) 1.88 2.1056 - - - 0.03 -

pendimethalin 6 0 17581 -0.5 (EL) 1.98 2.2176 0.00535 0.01186 1.19E-06 0.03 0.00395

Trifloxysulfuron-sodium 63.5 306 5.6 (VH) 0.012 0.01344 0.216 0.0029 2.90E-07 0.237 0.00012

trifluralin 181 15800 -0.4 (EL) 2 2.24 0.00613 0.01373 1.37E-06 0.024 0.00572

Herbicide A.I.s with Potential Displacement of Preemergent Acres

88.4 2 2.24
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 496 of 946

2 Gustafson DI (1989): Groundwater ubiquity score: A simple method for assessing pesticide leachability. Environ Toxicol. Chem. 8, 339–357. GUS is calculated as GUS = LOG10(soil halflife)*(4-LOG10(Koc)). The interpretation of GUS as a measure of the likelihood of leaching is as follows: < 0.1 = Extremely Low (EL); 0.1 – 1.0 = Very Low (VL); 1.1 – 2.0 = Low (L); 

2.1 – 3.0 = Moderate (M); 3.1 – 4.0 = High (H); > 4.0 = Very High (VH).

3 Maximum labeled single application rate to cotton. This rate was converted to kg/hectare (ha) units using: 1 lb = 0.454 kg and 1 acre = 0.405 ha.

4 The Footprint database, as presented by IUPAC http://sitem.herts.ac.uk/aeru/iupac/index.htm, provides a SCI-GROW concentration estimate for groundwater based on the a.i.s 

chemical properties using a consistent set of assumptions, including a 1 kg/ha application. This was converted to a concentration estimate by multiplying by the maximum single cotton 

application rate in kg/ha.

5 Using standard EPA assumptions for a child’s water consumption and weight (1 liter per day, 10 kg body weight), the groundwater concentration estimate was converted to a daily exposure 

estimate.

6 The chronic population adjusted dose (cPAD) as determined by EPA risk assessments. 

7 The child’s daily exposure estimate was compared to the chronic population adjusted dose (cPAD) as determined for the a.i. by EPA, and expressed as a percentage.

8 The Groundwater and Leaching score is determined by combining two criteria listed in Table 53. A GUS groundwater vulnerability index that is rated high (H) or very high (VH) 

constitutes one criterion. When the Child's water exposure is greater than 0.001 that constitutes a second criterion. When both criteria are exceeded, the a.i. is marked with a Black Circle. 

When only one is exceeded, the a.i. is marked with a half Circle. Exceedance of neither criterion earns a White Circle.

* Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated pest management system.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 497 of 946

A.4.4.2.5. Summary of Human Health and Environmental Risk

Table A-54 provides a one-page summary scorecard of the specific risk reduction opportunities 

versus each of the alternative active ingredients. Each of the columns in Table A-54 repeats the risk 

scores presented in Tables A-42 through A-46. The last column in Table A-54 is a summary where 

the number of Half and Black circles for each a.i. is added across to determine an overall Human 

Health and Environmental Summary Score. In each individual risk category and in the overall 

human health and environmental risk, dicamba has a favorable risk comparison. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 498 of 946

Table A-54. Summary of Comparative Analysis of Dicamba and Alternative Herbicides 

Used in Cotton

1 See Table A-49 for details.

2 See Table A-50 for details.

3 See Table A-51 for details.

4 See Table A-52 for details. 

5 See Table A-53 for details.

Note: Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an 

integrated pest management system.

Active Ingredient Summary

Acute 

Toxicity 

Risk 1

Cancer 

Risk 2

Chronic 

Risk 2

Aquatic 

Animal 

Risk 3

Aquatic 

Plant Risk 

4

Ground 

Water / 

Leaching 

Risk 5

Number of 

Half and 

Black Cirlces

dicamba acid /DGA salt 4 0

glufosinate-ammonium * * * * * * *

glyphosate (salts) * * * * * * *

2,4-D DMA (salts) 4

2,4-D EHE (esters) 4

flumiclorac pentyl 2

S-metolachlor 5

oxyfluorfen 6

pyraflufen ethyl 4

rimsulfuron 2

thifensulfuron methyl 2

tribenuron methyl 5

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

carfentrazone ethyl 4

fluometuron 5

fomesafen sodium 4

paraquat dichloride 5

prometryn 4

Pyrithiobac-sodium 3

Herbicide A.I.s with Potential Displacement of Postemergent Acres

flumioxazin 6

MSMA 3

pendimethalin 5

Trifloxysulfuron-sodium 3

trifluralin 6

Human Health Risk Measures Environmental Risk Measures

Herbicide A.I.s with Potential Displacement of Preemergent Acres
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 499 of 946

A.4.4.2.6. Comparative Herbicide Effectiveness in Cotton

Monsanto scientists have projected that the new use of dicamba in DGT cotton will displace the use 

of certain currently used herbicides in cotton. This section describes some of the advantages and 

disadvantages of dicamba and alternate herbicides used in cotton cultivation. This analysis shows 

the reasons farmers would be expected to adopt the use of dicamba in their cotton cultivation 

practice.

To summarize the comparative herbicidal effectiveness in this analysis, Table A-55 contains a 

column titled “Herbicidal Efficacy” in which a White Circle means that the a.i. provides commercial 

level control (>85%) of at least 50% of the hard-to-control or resistant weeds. A Half Circle means 

that the a.i. provides commercial level control of at least 30% of the hard-to-control or resistant 

weeds. And a Black Circle means that the a.i. provides commercial level control on less than 30% of 

the hard-to-control or resistant weeds. 

Table A-55 also contains a column titled “Palmer amaranth resistance to the class” in which the 

various herbicides are compared relative to the presence or absence of recorded resistance to Palmer 

amaranth and/or other Amaranthus spp. Palmer amaranth and Amaranthus spp. were selected for 

this comparison because of the importance of controlling glyphosate-resistant biotypes of these 

species in cotton from an agronomic standpoint. A White Circle indicates no resistance to any 

Amaranthus species in the U.S. A Half Circle indicates no resistance to Palmer amaranth but 

resistance to other Amaranthus species. A Black Circle indicates resistance to Palmer amaranth in 

the U.S.

Another important measure of herbicidal efficacy is the number of herbicide-resistant weeds to the 

class. Table A-55 includes a column titled “Number of resistant weeds to the class,” in which a 

White circle indicates resistance to 10 or fewer weed species. A Half Circle indicates resistance to 

between 10 and 50 weed species. A Black Circle indicates resistance to greater than 50 weed species. 

In addition, Table A-55 includes a column titled “Long Rotational Restrictions,” in which 

information from label use restrictions is summarized. A White Circle indicates a waiting period of 

6 months or less. A Half circle indicates a waiting period of 6 to 12 months. And A Black Circle 

indicates a waiting period of greater than 12 months. 

Because DGT cotton is tolerant to dicamba, the use of dicamba in DGT cotton provides good crop 

safety. Table A-55 includes a column in which the crop injury potential is summarized. A White 

Circle means the a.i. does not cause significant cotton injury. A Half Circle means that the a.i. does 

not cause significant crop injury when applied prior to cotton emergence or with a hooded sprayer. 

A Black Circle means that the a.i. will cause significant cotton injury regardless of application timing. 

Therefore, the use of dicamba in DGT cotton will provide an additional mode-of-action for 

postemergent weed control with good crop safety to DGT cotton.

Table A-55 includes a “Summary” column where the number of Half and Black Circles are added 

across the rows to provide an overall Agronomic Risk Summary Score. A lower number of Half or 

Black Circles indicates a relatively lower potential agronomic risk.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 500 of 946

Table A-55. Alternative Herbicide Agronomic Risk Measures

1 Information from the Herbicide Resistance Action Committee (HRAC). 

http://www.hracglobal.com/Publications/ClassificationofHerbicideSiteofAction/tabid/222/Default.aspx 

2 A White Circle means that the a.i. provides commercial level control (>85%) of at least 50% of the hard-to-control or resistant weeds, 

Half Circle means that the A.I provides commercial level control of at least 30% of the hard-to-control or resistant weeds, and Black 

Circle means the a.i. provides commercial level control on less than 30% of the hard-to-control or resistant weeds.

3 Information from http://www.weedscience.org/summary/MOASummary.asp [accessed 16-Apr-2013]. A White Circle indicates no 

resistance to any Amaranthus species in the US. A Half Circle indicates no resistance to Palmer amaranth but resistance to other 

Amaranthus species. A Black Circle indicates resistance to Palmer amaranth in US.

4 Information from http://www.weedscience.org/summary/MOASummary.asp [accessed 16-Apt-2013]. A White Circle indicates 

resistance to 10 or less weed species. A Half Circle indicates resistance to between 10 and 50 weed species. A Black Circle indicates 

resistance to greater than 50 weed species.

5 Alternate herbicides that require long waiting periods between application and subsequent planting of a crop other than cotton, 

information from label use restrictions. This constraint is a disadvantage to farmers. A White circle indicates a waiting period of 6 

months or less, a Half circle indicates a waiting period of 6 to 12 months, and a Black circle indicates a waiting period of greater than 

12 months.

6 Herbicides with potential for serious injury to cotton. White Circle means that the a.i. does not cause significant crop injury. Half 

Circle means that when applied prior to crop emergence or used under a hooded sprayer the a.i. does not cause significant crop Injury.

Black Circle means that a.i. may cause significant crop injury regardless of application timing.

* Not evaluated

Active Ingredient Summary

Chemical Family 

or Class1

Herbicidal 

Efficacy 2

Palmer 

amaranth 

resistance 

to the class3 

Number of 

resistant 

weeds to 

the class4

Long 

Rotational 

Restrictions 

5

Serious 

Crop Injury 

Potential 6

Number of 

Half and 

Black Circle 

Entries

dicamba acid /DGA salt 4 Benzoic Acid 0

glufosinate-ammonium

Glutamine

Synthetase *

glyphosate (salts) EPSP *

2,4-D DMA (salts) Phenoxy 4

2,4-D EHE (esters) Phenoxy 4

flumiclorac pentyl Dicarboximide 2

S-metolachlor Chloracetamide 2

oxyfluorfen Diphenyl-ether 4

pyraflufen ethyl Phenyl pyrazole 3

rimsulfuron Sulfonyl Urea 5

thifensulfuron methyl Sulfonyl Urea 4

tribenuron methyl Sulfonyl Urea 4

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

carfentrazone ethyl Triaolinone 3

fluometuron Urea 5

Fomesafen sodium Diphenyl-ether 3

paraquat dichloride Bipyridylium 2

prometryn Triazines 5

Pyrithiobac-sodium

Pyrimidinyl

benzoates 4

Herbicide A.I.s with Potential Displacement of Postemergent Acres

flumioxazin Phenylphthalimide 3

MSMA Organo

Arsenicals 2

pendimethalin Dinitroaniline 4

Trifloxysulfuron-sodium Sulfonylurea 4

trifluralin Dinitroaniline 3

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Agronomic Risk Measures
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 501 of 946

In addition to the items summarized in table A-55, the new use of dicamba in DGT cotton offers 

additional benefits to the cotton farmer. Dicamba provides control of over 95 annual and biennial 

weed species and control or suppression of over 100 perennial broadleaf and woody species. 

Dicamba provides more effective preemergent weed control than 2,4-D on cutleaf evening 

primrose, clover, and chickweed (Loux et al., 2009). Furthermore, dicamba provides excellent 

control compared to 2,4-D on summer annuals including those with a prostrate growth habit such 

as knotweed and purslane. With regard to winter annual weeds, University of Arkansas data 

indicated that dicamba is more effective in controlling marestail compared to 2,4-D (Arkansas, 

2011).

Dicamba also provides excellent control of wild buckwheat, while 2,4-D has only limited activity and 

provides inadequate control (Zollinger at al.). Other preemergent or postemergent herbicides often 

provide incomplete control of wild buckwheat including dinitroanilines or PPO inhibitors. The 

most effective herbicides for buckwheat are dicamba and some sulfonylurea products. However, 

some of the sulfonylurea herbicides may persist and carry over for more than one growing season, 

especially in high pH soils.

Dicamba has been valued as more efficacious on lambsquarters than fomesafen, based on university 

weed control guidelines (Moeching, et al., 2010; Illinois, 2008). In addition, dicamba exhibits 

improved control of sicklepod, kochia, and common ragweed, and waterhemp compared to 

fomesafen. 

Dicamba use on DGT cotton will reduce the number of applications of soil residual herbicides 

needed for season long control of Palmer amaranth (fomesafen, pyrithiobac, fluometuron) (Steckel, 

2012; Culpepper, 2012). Multiple applications of residual herbicides are needed today because of the 

lack of effective postemergent options. 

Dicamba use in DGT cotton will continue to support the adoption of IPM (integrated pest 

management) practices in cotton by allowing farmers to continue to focus primarily on 

postemergent, in-crop weed control, as they have practiced with glyphosate- and glufosinate-tolerant 

cotton, and by making current practices more effective by providing an additional mode-of-action 

option. This will allow farmers to delay some herbicide treatments until field scouting indicates a 

need for additional weed control, consistent with the principles of IPM. Dicamba, as a companion 

product to glyphosate and glufosinate, will also continue to foster adoption of and maintain the use 

of conservation tillage practices, because farmers prefer to use postemergent products, such as 

dicamba in DGT cotton, rather than rely on preemergent applications of soil-residual herbicides.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 502 of 946

A.4.4.2.7. Summary of Dicamba Reduced Risk Opportunity in Cotton Production

Monsanto has requested reduced risk status for the new use of dicamba in DGT cotton based on 

the introduction of this trait and dicamba use pattern to the cotton weed management system that 

will:

 Reduce risks to human health;

 Reduce risks to non-target organisms;

 Reduce the potential for contamination of groundwater, surface water, or other valued 

environmental resources; and

 Improve the management of herbicide-resistant weeds, thus overall weed management in 

cotton, which is critical for the long term sustainability of cotton in the U.S.

In addition, dicamba use on DGT cotton provides a favorable comparative risk profile, the reduced 

need to use certain higher relative risk herbicides, and improved management of herbicide-resistant 

weeds, and thus overall weed management and sustainability of cotton production in the United 

States. Dicamba will provide a valuable weed management tool for this important U.S. agricultural 

crop; provide additional flexibility and weed control options to cotton farmers; help to mitigate the 

potential for the development of resistant herbicide genotypes for all herbicide modes-of-action that 

are currently registered for use in cotton; and support adoption of no-till and conservational tillage 

practices. 

Table A-56 provides a one-page summary scorecard of the specific risk reduction opportunities and 

the acres projected to be displaced of the alternate active ingredients. Each of the columns in Table 

A-49 repeat the risk scores presented in Tables A-42 to A-47, plus the agronomic risk measures 

shown in table A-48. The right-most column of Table A-49 presents a sum of the number of Half 

and Black Circle entries for each a.i. across the columns. This sum represents the overall risk score 

that each herbicidal a.i. achieved based on this analysis. A lower number denotes a lower potential 

(more favorable) risk profile. Dicamba’s risk profile was more favorable than all of the alternate 

herbicides used in cotton. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 503 of 946

Table A-56. Summary of Dicamba Reduced Risk Opportunities vs. Alternative Herbicides

1 See Table A-54 for details.

2 See Table A-55 for details

Note: Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated pest management system. 

A Black Circle represents a relatively higher risk among the alternates considered for that general risk parameter. A Half Circle represents an intermediate risk among the 

alternates considered. A White Circle represents a reduced risk among the alternates considered.

Summary

Acute 

Toxicity 

Risk 

Cancer 

Risk 

Chronic 

Risk 

Aquatic 

Animal 

Risk 

Aquatic 

Plant Risk 

Ground 

Water / 

Leaching 

Risk 

Volatility 

Risk

Herbicidal 

Efficacy 

Palmer 

amaranth 

resistance 

to the class

Number of 

resistant 

weeds to 

the class

Long 

Rotational 

Restrictions 

Serious 

Crop Injury 

Potential

Acres 

Displaced 

at Peak3

Number of 

Half and 

Black 

Circle 

Entries

dicamba acid /DGA salt * 0

2,4-D DMA (salts) 8

2,4-D EHE (esters) 8

flumiclorac pentyl 6,000 4

S-metolachlor 152,000 7

oxyfluorfen 31,000 1 0

pyraflufen ethyl 18,000 7

rimsulfuron 4,000 7

thifensulfuron methyl 31,000 6

tribenuron methyl 27,000 9

carfentrazone ethyl 27,000 7

fluometuron 248,000 1 0

fomesafen sodium 639,000 7

paraquat dichloride 534,000 7

prometryn 449,000 9

Pyrithiobac-sodium 536,000 7

flumioxazin 324,000 9

MSMA 213,000 5

pendimethalin 11,000 9

Trifloxysulfuron-sodium 303,000 7

trifluralin 6,000 9

Herbicide A.I.s with Potential Displacement of Postemergent Acres

608,000

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

Human Health Risk Measures 1Environmental Risk Measures 1 Agronomic Risk Measures 2

Herbicide A.I.s with Potential Displacement of Preemergent Acres
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 504 of 946

A.5. SUMMARY AND CONCLUSION

Dicamba’s use is expected to grow with the deregulation of DT soybean and DGT cotton. As the 

foregoing analysis of grower survey data shows, dicamba use will likely increase for both 

preplant/pre-emergence (PRE) and post-emergence (POST) in-crop applications, as measured in

total acres treated and pounds of dicamba. With or without the introduction of DT soybean and 

DGT cotton, non-glyphosate herbicide usage is expected to increase to support the management of 

glyphosate-resistant weeds. If DT soybean and DGT cotton are approved for use, it is expected that 

glyphosate will continue to be the base herbicide applied in combination with other herbicides, 

including dicamba, as the central component of weed management systems. This competitive 

environment will combine with the introduction of other herbicide-tolerant traits in soybean and 

cotton crops to limit the expected increase in dicamba use.

Observable qualities of certain non-glyphosate herbicides—lower efficacy, carryover concerns, 

existing resistance, use restrictions, and/or crop safety—suggest a number of PRE and POST 

herbicides that dicamba will displace if DT soybean and DGT cotton are deregulated. Overall 

herbicide usage is expected to grow under any scenario; however, the growth in dicamba usage 

accounts for a relatively small percentage of the overall projected growth in herbicide usage in 

glyphosate-tolerant soybean and cotton production.

The foregoing comparative analysis of dicamba and alternative soybean and cotton herbicides reflects 

dicamba’s favorable health and ecological risk profile relative to a some of non-glyphosate herbicides 

currently approved and on the market. The analysis accounted for acute health risks, chronic risks, 

cancer risk, risk to infants and children, and risks to aquatic animals and plants. Further, dicamba 

was found to be more efficacious and better at weed management than a number of currentlyavailable herbicides.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 505 of 946

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ALTERNATIVE HERBICIDE-SPECIFIC REFERENCES

The following active ingredient specific references were used to generate the comparative summary 

information contained in Tables A-26, A-27, and A-28.

2,4-D

U.S. EPA. 2004. Environmental Fate and Effects Division’s Risk Assessment for the Reregistration 

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2,4-DB

U.S. EPA. 2005. Registration Eligibility Decision for 2,4-DB”. U.S. Environmental Protection 

Agency, Office of Pesticides, Prevention, and Toxic Substances, Document EPA738-R-05-001, 

January, 2005.

Acifluorfen, Sodium

U.S. EPA. 2003. R.E.D. Facts Sodium Acifluorfen (Blazer®). U.S. Environmental Protection 

Agency, Document EPA-738-F-04-001, September 2003.

U.S. EPA. 2004. Registration Eligibility Decision for Sodium Acifluorfen, Case No. 2605. U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, 
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(undated). See also “Sodium Acifluorfen RED; Notice of Availability”. 69 FR 4139 - 4138, January 

28, 2004.

U.S. EPA. 2002. Sodium Acifluorfen, HED Chapter for the Reregistration Eligibility Decision. 

U.S. Environmental Protection Agency Office of Pesticides, Prevention, and Toxic Substances, DP 

Barcode: D279497, January 15, 2002.

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm 

http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Chlorimuron

U.S. EPA. 2009. Chlorimuron-ethyl: Revised Human Health Risk Assessment for Proposed Uses 

On Cranberry and Low-growing Berry Subgroup 13-07H, except Strawberry, PP# 6E7153. U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP 

Barcode D361368, February 5, 2009. 

U.S. EPA. 2004. Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment 

Progress and Risk Management Decision (TRED) for Chlorimuron Ethyl. U.S. Environmental 

Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, September 22, 2004. 

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm 

http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Cloransulam

U.S. EPA. 1997. Pesticide Fact Sheet; Name of Chemical: Cloransulam-methyl. U.S. 

Environmental Protection Agency Office of Pesticides, Prevention, and Toxic Substances, October 

29, 1997.

U.S. EPA. 1997. Cloransulam-methyl; Pesticide Tolerances. U.S. Environmental Protection 

Agency, 62 FR 49158-49163, September 19, 1997. 

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm 

http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Dicamba

Hoberg, James R. “Dicamba technical – Determination of Effects on Seed Germination, Seedling 

Emergence, and Vegetative Vigor of Ten Plant Species”. Springborn Laboratories, 1993.

U.S. EPA. 2009. Registration Eligibility Decision for Dicamba and Associated Salts. U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, June 8, 

2006, as amended June 17, 2009.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 512 of 946

U.S. EPA. 2005. Dicamba: HED Chapter of the Reregistration Eligibility decision Document 

(RED) - Phase I. U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and 

Toxic Substances, DP Bar Code D317720, September 13, 2005. 

U.S. EPA. 2005. EFED Reregistration Chapter For Dicamba / Dicamba Salts. U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Bar 

Code 317976, August 31, 2005.

“Dicamba: Acute and Chronic Aggregate Dietary (Food and Drinking Water) Exposure and Risk 

Assessments for the Proposed Section 3 Registration Action on Sweet Corn.” U.S. Environmental 

Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Bar Code 347355, 

2008. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2007-0325-0006 .

“Dicamba; Pesticide Tolerance.” U.S. Environmental Protection Agency, 2-Apr-2008. 73 FR 17914-

18.

“Clarity Herbicide Label.” BASF Corporation, 2010. http://www.cdms.net/LDat/ld797012.pdf 

[Accessed 22-Dec-2011].

Diuron

“Reregistration Eligibility Decision (RED) for Diuron.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, September 30, 2003. 

http://www.epa.gov/oppsrrd1/REDs/diuron_red.pdf .

“Diuron; Pesticide Tolerance.” U.S. Environmental Protection Agency, 13-Jun-2007. 72 FR 32522-

40.

“Diuron. Updated Aggregate Risk Assessment to Support Permanent Tolerances for Residues in 

Cactus, Peppermint Tops, Spearmint Tops, and Fish.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, DP Bar Code D335228, May 15, 2007. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-0559-0007.

“Direx 4L Herbicide Label.”E.I. du Pont de Nemours and Co.,2011. 

http://www.cdms.net/LDat/ld7QP001.pdf [Accessed 22-Dec-2011].

Flumiclorac-pentyl

U.S. EPA. 2009. Registration Review - Preliminary Problem Formulation for the Ecological Risk 

Assessment of Flumiclorac-pentyl. U.S. Environmental Protection Agency, Office of Pesticides, 

Prevention, and Toxic Substances, DP Bar Code 362087, July 10, 2009. EPA-HG-OPP-2009-0084-

0004.

U.S. EPA. 2009. Flumiclorac Pentyl: Revised Human Health Assessment Scoping Document in 

Support of Registration Review. U.S. Environmental Protection Agency, Office of Pesticides, 

Prevention, and Toxic Substances, DP Bar Code D368451, August 28, 2009. 

U.S. EPA. 2005. Report of Food Quality Protection Act (FQPA) Tolerance reassessment Progress 

and Risk Management decision (TRED) for Flumiclorac pentyl. U.S. Environmental Protection 

Agency, Office of Pesticides, Prevention, and Toxic Substances, August 23, 2005. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 513 of 946

U.S. EPA. 2006. Flumiclorac pentyl; Pesticide Tolerance. U.S. Environmental Protection Agency, 

71 FR 11526-11533, March 8, 2006.

Flumioxazin

U.S. EPA. 2007. Flumioxazin. Human Health Risk Assessment for the Proposed Food Use of the 

Herbicide Flumioxazin on Alfalfa, Asparagus, Dry Beans, Fruiting Vegetables (Group 8, Including 

Okra), Melons (Subgroup 9A), Bushberries (Subgroup 13B), and Tree Nuts (Group 14), and a 

Request for an Amended Use on Garlic. U.S. Environmental Protection Agency, Office of 

Pesticides, Prevention, and Toxic Substances, DP Bar Code 336194, November 28, 2007.

U.S. EPA. 2008. Flumioxazin; Pesticide Tolerance. U.S. Environmental Protection Agency, 73 FR 

11826-11831, March 5, 2008.

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System forthe Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

“Flumioxazin. Human Health Risk Assessment for a Proposed Aquatic Use.” U.S. Environmental 

Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Bar Code D379028, 

July 14, 2010. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2008-0781-0029.

“Valor SX Herbicide Label.” Valent U.S.A. Corporation, 2010. 

http://www.cdms.net/LDat/ld3LL041.pdf [Accessed 22-Dec-2011].

Fluometuron

“Reregistration Eligibility Decision (RED) for Fluometuron.” U.S. Environmental Protection 

Agency, Office of Pesticides, Prevention, and Toxic Substances, September, 2005. 

http://www.epa.gov/oppsrrd1/REDs/fluometuron_red.pdf .

“Fluometuron: Revised HED Risk Assessment for Phase III of the Reregistration Eligibility 

Decision.” U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic 

Substances, DP Bar Code 341152, February 1,2005. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2004-0372-0008.

“Fluometuron. Revised Acute, Chronic, and Cancer Dietary Exposure Assessments for the 

Reregistration Eligibility Decision (RED) Document.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, DP Bar Code D321682, September 27, 

2005. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2004-0372-0029 .

“Cotoran 4L Herbicide Label.” Makhteshim Agan of North America, 2009. 

http://www.cdms.net/LDat/ld9D1003.pdf .

Fluthiacet-methyl

U.S. EPA. 1999. Pesticide Fact Sheet; Name of Chemical: Fluthiacet-methyl. U.S. Environmental 

Protection Agency Office of Pesticides, Prevention, and Toxic Substances, April, 1999.

U.S. EPA. 2001. Fluthiacet-methyl; Pesticide Tolerance. 66 FR 65839-65850, December 21, 2001. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 514 of 946

U.S. EPA. 2006. Fluthiacet-methyl; Pesticide Tolerance. 71 FR 77620-77625, December 27, 2006.

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Fomesafen

U.S. EPA. 2006. Fomesafen; Pesticide Tolerance. U.S. Environmental Protection Agency, 71 FR 

25945 - 25951, May 3, 2006.

U.S. EPA. 2007. Fomesafen Summary Document; Registration Review - Initial Docket March 

2007. U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic 

Substances, Docket No. EPA-HQ-OPP-2006-0239, March 22, 2007. 

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm 

http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

“Ecological Risk Assessment for Use of Fomesafen On Cotton (DP302766), Snap Beans ( 

DP314014) and Dry Beans (DP314112).” U.S. Environmental Protection Agency, Office of 

Pesticides, Prevention, and Toxic Substances, January 2006 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-0239-0009 .

Fomesafen TerrPlant results. U.S. Environmental Protection Agency, Office of Pesticides, 

Prevention, and Toxic Substances, Docket No. EPA-HQ-OPP-2006-0239-0013, 2005. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-0239-0013 .

“Fomesafen Sodium: HED Registration Review Problem Formulation Document.” U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP 

Barcode D306022, 2007. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-

0239-0004 .

“FlexStarHerbicide label.” Syngenta Crop Protection Inc., 2010. 

http://www.cdms.net/LDat/ld6BM020.pdf [Accessed 22-Dec-2011].

“Reflex Herbicide label.” Syngenta Crop Protection Inc., 2010. 

http://www.cdms.net/LDat/ld6BJ013.pdf [Accessed 22-Dec-2011].

Glufosinate

U.S. EPA. 2003. Glufosinate Ammonium; Pesticide Tolerance. U.S. Environmental Protection 

Agency, 68 FR 55833 - 55849, September 29, 2003. 

U.S. EPA. 2009. Glufosinate Summary Document; Registration Review - Initial Docket March 

2008, Case #7224. U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and 

Toxic Substances, Docket No. EPA-HQ-OPP-2008-0190, March 19, 2009. 

“ Glufosinate Final Work Plan.” U.S. Environmental Protection Agency, Office of Pesticides, 

Prevention, and Toxic Substances, August, 2008. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2008-0190-0015 . 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 515 of 946

“Glufosinate Ammonium (PC Code: 128850). Section 3 Registrations for Transgenic Cotton and 

Cotton (ID# - 0F06140), Transgenic Rice (ID# - 0F06210), and Bushberry (ID# - 2E06404). 

Human Health Risk Assessment.” U.S. Environmental Protection Agency, Office of Pesticides, 

Prevention, and Toxic Substances, DP Barcode D290086. August 7, 2003.

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2008-0190-0005 .

“Glufosinate-ammonium: Ecological Risk and Drinking Water Exposure Assessment for the Section 

3 New Use of Glufosinate-ammonium on Cotton.” U.S. Environmental Protection Agency, Office 

of Pesticides, Prevention, and Toxic Substances, DP Barcodes 318746, 318747,February 28, 2006. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2008-0190-0010 .

“EFED Risk Assessment for use of Glufosinate-ammonium on canola, potatoes

and Sugar Beets.” U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and 

Toxic Substances, DP Barcode D240586, April, 2000. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2008-0190-0006 .

“Ignite Herbicide label.” Bayer Crop Science LP, 2011. http://www.cdms.net/LDat/ld99B003.pdf

[Accessed 22-Dec-2011].

Glyphosate

U.S. EPA 2009. Problem Formulation for the Ecological Risk and Drinking Water Exposure 

Assessments in Support of the Registration Review of Glyphosate and Its Salts. EPA-HQ-OPP2009-0361-0007.

“Reregistration Eligibility Decision (RED) Glyphosate.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, Document EPA 738-R-93-014, September, 

1993. http://www.epa.gov/oppsrrd1/REDs/old_reds/glyphosate.pdf .

“Glyphosate. Dietary Risk Assessment in Support of the Requested use on Roundup Ready® Sweet 

Corn.” U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic 

Substances. DP Barcode D380165, August, 2010. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2009-0988-0005 .

“Glyphosate: Human Health Assessment Scoping Document in Support of Registration Review.” 

U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances. DP 

Barcode D362745, June, 2009. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP2009-0361-0006 .

“Registration Review- Preliminary Problem Formulation for the Ecological Risk and Drinking Water 

Exposure Assessments for Glyphosate and Its Salts.” U.S. Environmental Protection Agency, Office 

of Pesticides, Prevention, and Toxic Substances, DP Barcode 365851, June, 2009. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2009-0361-0007 .

“Notice of Filing Pesticide Petitions to Establish a Tolerance for Certain Pesticide Chemicals in or 

on Food.” U.S. Environmental Protection Agency,67 FR 18894 – 18899, April 17, 2002.

“Roundup WeatherMAX Herbicide label.” Monsanto Co., 2009.

http://www.cdms.net/LDat/ld5UJ064.pdf [Accessed 22-Dec-2011].
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 516 of 946

Imazamox

U.S. EPA. 1997 Pesticide Fact Sheet. Name of Chemical: Imazamox (Raptor Herbicide) Reason 

for Issuance: Conditional Registration. Date Issued: May 22, 1997.

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Imazaquin

U.S. EPA. 2005. Imazaquin and its Salts: HED Chapter of the Tolerance Reassessment Eligibility 

Decision (TRED) Document DP Barcode: D302939. U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, October 31, 2005. 

U.S. EPA. 2005. Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment 

Progress and Risk Management Decision (TRED) for Imazaquin. U.S. Environmental Protection 

Agency, Office of Pesticides, Prevention, and Toxic Substances, Document No. EPA 738-R-00-009, 

December, 2005. 

U.S. EPA. 2005. Drinking Water Assessment for Imazaquin and its Salts. Environmental 

Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Barcode: D313182, 

June 21, 2005. 

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Imazethapyr

U.S. EPA. 2002. Imazethapyr; Pesticide Tolerance. U.S. Environmental Protection Agency 67 FR 

55323 - 55331, August 29, 2002. 

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

Isoxaflutole

U.S. EPA. 1998. Pesticide Fact Sheet; Name of Chemical: Isoxaflutole. U.S. Environmental 

Protection Agency Office of Pesticides, Prevention, and Toxic Substances, September 15, 1998. 

U.S. EPA. 1998. Isoxaflutole; Pesticide Tolerance. U.S. Environmental Protection Agency, 63 FR 

50773 - 50784, September 23, 1998. 

Lactofen

U.S. EPA. 2006. EFED Problem Formulation for Lactofen Review. DP Barcode: 323196. 

December 13, 2006. EPA-HQ-OPP-2005-0287-0004.

U.S. EPA. 2004. Lactofen; Pesticide Tolerance. U.S. Environmental Protection Agency, 69 FR 

57207 - 57216, September 24, 2004. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 517 of 946

U.S. EPA. 2003. Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment 

Progress and Risk Management Decision (TRED) for Lactofen. U.S. Environmental Protection 

Agency, Office of Pesticides, Prevention, and Toxic Substances, Document No. EPA 738-R-04-002, 

September 24, 2003. 

U.S. EPA. 2000. Lactofen: Preliminary Human Health Risk Assessment for Tolerance 

Reassessment, Incorporating Revised Cancer Unit Risks. U.S. Environmental Protection Agency 

Office of Pesticides, Prevention, and Toxic Substances, DP Barcode: D269621, October 12, 2000. 

Mesotrione

U.S. EPA. 2001. Pesticide Fact Sheet; Name of Chemical: Mesotrione. Office of Pesticides, 

Prevention, and Toxic Substances, June 4, 2001.

U.S. EPA. 2009. Mesotrione; Pesticide Tolerances. U.S. Environmental Protection Agency, 74 FR 

67119 - 67124, December 18, 2009. 

U.S. EPA. 2009. Mesotrione: Human-Health Risk Assessment for Section 3 New Use on Soybeans. 

U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP 

Barcode: D357890, August 12, 2009. 

U.S. U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the 

Regional IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

MSMA

“Revised Reregistration Eligibility Decision for MSMS, DSMA, CAMA, and Cacodylic Acid.” U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances. Docket 

EPA-HQ-OPP-2006-0201, Document EPA-738-R-06-021, August 10, 2006. 

http://www.epa.gov/oppsrrd1/REDs/organic_arsenicals_red.pdf .

“Amendment to Organic Arsenicals RED.”U.S. Environmental Protection Agency, Office of 

Pesticides, Prevention, and Toxic Substances, April 22, 2009. 

http://www.epa.gov/oppsrrd1/REDs/organic-arsenicals-amended.pdf .

“Ecological Risk Assessment; Re-registration Eligibility Document for Sodium and Calcium Salts of 

Methanearsonic Acid (MSMS/DSMA/CAMA).” U.S. Environmental Protection Agency, 

Environmental Fate and Effects Division, September 24, 2001. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2006-0201-0010 .

“MSMA 6 Plus Herbicide label.” Drexel Chemical Co., [date unknown] 

http://www.cdms.net/LDat/ld47P004.pdf [Accessed 26-Dec-2011].

“Organic Arsenicals Label Amendment, EPA Reg. Nos. 62719-339, 62719-340, 62719-343.” U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, May 26, 

2009. http://www.epa.gov/pesticides/chem_search/ppls/062719-00343-20090526.pdf .

Paraquat
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 518 of 946

U.S. EPA. 1997. Registration Eligibility Decision for Paraquat Dichloride. U.S. Environmental 

Protection Agency Office of Pesticides, Prevention, and Toxic Substances. Document No. EPA 

738-F-96-018, August, 1997. 

U.S. EPA. 2006. Paraquat Dichloride; Pesticide Tolerance. U.S. Environmental Protection Agency, 

71 FR 52487 - 52494, September 6, 2006.

U.S. EPA. 2010. OPP Pesticide Ecotoxicity Database. National Information System for the Regional 

IPM Centers. http://www.ipmcenters.org/Ecotox/index.cfm Accessed May 28, 2010.

“Gramoxone Inteon Herbicide label.” Syngenta Crop Protection Inc., 2010. 

http://www.cdms.net/LDat/ld77A041.pdf [Accessed 26-Dec-2011].

Pendimethalin

“Reregistration Eligibility Decision (RED) Pendimethalin.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, Document EPA-738-R-97-007, June, 1997. 

http://www.epa.gov/oppsrrd1/REDs/0187red.pdf .

“Pendimethalin; Pesticide Tolerance.” U.S. Environmental Protection Agency, 71 FR 18628 - 18635, 

April 12, 2006.

“Pendimethalin: REVISED HED Human Health Risk Assessment to Support Section 3 

Registration for use on Carrots, Mint, Citrus, and Tree Nuts.” U.S. Environmental Protection 

Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Barcode No.: D3125176, 

March 3, 2006. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2005-0056-0002

.

“Prowl 3.3 EC Herbicide label.” BASF Corporation, 2008. 

http://www.cdms.net/LDat/ld867008.pdf [Accessed 26-Dec-2011].

Prometryn

“Reregistration Eligibility decision (RED) Prometryn.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, Document EPA-738-R-95-033, February 

1996. http://www.epa.gov/oppsrrd1/REDs/0467.pdf .

“Prometryn. Section 3 Registration Request to Add New Uses on Carrot, Celeriac, Cilantro, Okra, 

Parsley, and Leaf Petioles (Crop Subgroup 4B). Human-Health Risk Assessment.” U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP 

Barcode D367830, August 5, 2009. http://www.regulations.gov/#!documentDetail;D=EPA-HQOPP-2008-0773-0008 .

“Prometryn (CAS Reg. No. 7287-19-6) Tier I Drinking Water Assessment.” U.S. Environmental 

Protection Agency, Office of Pesticides Programs, Environmental fate and Effects Division, DP 

Barcodes 357096, 357099, June 19, 2009. http://www.regulations.gov/#!documentDetail;D=EPAHQ-OPP-2008-0773-0005.“Caparol 4L Herbicide labrl.” Syngenta Crop Protection Inc., 2009 

http://www.cdms.net/LDat/ld515020.pdf [Accessed 27-Dec-2011].

Pyrithiobac
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 519 of 946

“Pyrithiobac Sodium (sodium 2-chloro-6-[(4,6-dimethoxypyrimidin-2-yl)thio]benzoate); Pesticide 

Tolerance.” U.S. Environmental Protection Agency, 67FR 72104 – 72110, December 4, 2002.

“Pyrithiobac Sodium. Human-Health Assessment Scoping Document in Support of Registration 

Review.” U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution 

Prevention, DP Barcode 389518, September 16, 2011. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2011-0661-0004 .

“Pyrithiobac Sodium Summary Document, Registration Review: Initial Docket.” Office of Pesticide 

Programs, Docket Number EPA-HQ-OPP-2011-0661, September 23, 2011. U.S. Environmental 

Protection Agency, http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2011-0661-

0002 .

“Registration Review: Preliminary Problem Formulation for Environmental Fate and Ecological 

Risk, Endangered Species, and Drinking Water Assessments for Pyrithiobac-Na (case# 7239).” U.S. 

Environmental Protection Agency, Environmental Fate and Effects Division, DP Barcode 

D389517, September 19, 2011. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP2011-0661-0003.

“Staple Herbicide label.”E.I. du Pont de Nemours and Co., 2006. 

http://www.cdms.net/LDat/ld170007.pdf [Accessed 27-December-2011].

“Staple LX Herbicide label.”E.I. du Pont de Nemours and Co., 2011. 

http://www.cdms.net/LDat/ld7DD009.pdf [Accessed 27-December-2011].

S- Metolachlor

“Reregistration Eligibility Decision (RED) Metolachlor.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, Document EPA-738-R-95-006, April, 1995. 

http://www.epa.gov/oppsrrd1/REDs/0001.pdf .

“Report of the Food Quality Protection Act (FQPA) Tolerance reassessment Progress and Risk 

Management Decision (TRED) for Metolachlor.” U.S. Environmental Protection Agency, Office of 

Pesticides, Prevention, and Toxic Substances, June 17, 2002. 

http://www.epa.gov/oppsrrd1/REDs/metolachlor_tred.pdf .

“S-Metolachlor; Pesticide Tolerances.” U.S. Environmental Protection Agency, 68 FR 54827 –

54834, September 19, 2003.

“S-metolachlor - Acute and Chronic Dietary and Drinking Water Exposure and Risk Assessment for 

Proposed New Use of S-metolachlor on Bushberry Subgroup 13-07B;Caneberry Subgroup 13-07A; 

Carrot; Cucumber; Leafy Brassica Greens Subgroup 5B; Melon Subgroup 9A; Okra; Bulb Onion 

Subgroup 3-07A; Green Onion Subgroup 3-07B; Sesame Seed; Sorghum; and Turnip Greens.” U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP 

Barcode 370429, June 30, 2010. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP2009-0814-0006 .

“Dual Magnum Herbicide label.” Syngenta Crop Protection Inc., 2011. 

http://www.cdms.net/LDat/ld0iA030.pdf [Accessed 26-Dec-2011].
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 520 of 946

“Sequence Herbicide label.” Syngenta Crop Protection Inc., 2011. 

http://www.cdms.net/LDat/ld6HK000.pdf [Accessed 26-Dec-2011].

Sulfentrazone

U.S. EPA. 2009. Revised EFED Problem Formulation for Sulfentrazone Registration Review. 

U.S. Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP 

Bar Code 363522, EPA-HQ-OPP-2009- 0624-0006. September 9, 2009. 

U.S. EPA. 2009. Sulfentrazone. REVISED Human Health Assessment Scoping Document in 

Support of Registration Review. U.S. Environmental Protection Agency, Office of Pesticides, 

Prevention, and Toxic Substances, DP Bar Code 369064, September 9, 2009. 

Tembotrione

U.S. EPA. 2007. Pesticide fact Sheet: Tembotrione. U.S. Environmental Protection Agency, Office 

of Pesticides, Prevention, and Toxic Substances, September, 2007. 

Thifensulfuron

U.S. EPA. 2007. Thifensulfuron Methyl; Pesticide Tolerance. U.S. Environmental Protection 

Agency, 72 FR 13179 - 13184, March 21, 2007. 

U.S. EPA. 2008. Ingredient: Thifensulfuron Methyl; Title: Label Amendments and petition for 

Tolerances on Wheat Forage and Hay, Oat Forage and Hay, and Barley Hay. U.S. Environmental 

Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Bar Code 350544, 

April 17, 2008. 

Trifloxysulfuron

“Trifloxysulfuron; Pesticide Tolerance.” U.S. Environmental Protection Agency, 68FR 54377 –

54386, September 13, 2003.

“Trifloxysulfuron-sodium; Notice of Filing a Pesticide Petition to Establish a Tolerance for a 

Certain Pesticide Chemical in or on Food.” U.S. Environmental Protection Agency, 68FR 13924 –

13930, March 21, 2003.

“Evaluation of the New Active Trifloxysulfuron Sodium in the Product Evoke Herbicide.” National 

Registration Authority for Agricultural and Veterinary Chemicals, Australia, August, 2002. 

http://www.apvma.gov.au/registration/assessment/docs/prs_trifloxysulfuron.pdf .

“Evoke herbicide label.” Syngenta Crop Protection Inc., 2011. 

http://www.cdms.net/LDat/ld6DU001.pdf [Accessed 27-December-2011].

“Suprend Herbicide label.” Syngenta Crop Protection Inc., 2010. 

http://www.cdms.net/LDat/ld6DU001.pdf [Accessed 27-December-2011].

Trifluralin
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“Reregistration Eligibility decision (RED) Trifluralin.” U.S. Environmental Protection Agency, 

Office of Pesticides, Prevention, and Toxic Substances, Document EPA-738-R-95-040, April 1996. 

http://www.epa.gov/oppsrrd1/REDs/0179.pdf .

“Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment Progress and Risk 

Management Decision (TRED) for Trifluralin.” U.S. Environmental Protection Agency, Office of 

Pesticides, Prevention, and Toxic Substances, August 31, 2004. 

http://www.epa.gov/oppsrrd1/REDs/trifluralin_tred.pdf .

“Trifluralin; Proposed Pesticide Tolerance.” U.S. Environmental Protection Agency, 69FR 68287–

68299, November 11, 2004.

“Treflan Herbicide label.” Dow AgroSciences LLC, 2008
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APPENDIX B: HERBICIDE RESISTANCE
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Table of Contents

B.1. Introduction and Background on Herbicide Resistance..................................................................527

B.1.1. Overview of Herbicide Resistance .....................................................................................527

B.1.2. The Herbicide Dicamba.......................................................................................................528

B.1.3. The Herbicide Glufosinate ..................................................................................................529

B.1.4. Herbicide-Resistant Weeds and Resistance Management Strategies.............................529

B.1.5. Characteristics of Herbicides and Herbicide Use Influencing Resistance ....................530

B.1.6. Mechanisms of Resistance and Inheritance of Resistance..............................................531

B.1.7. Weeds Resistant to Dicamba and Glufosinate .................................................................532

B.2. DT Soybean............................................................................................................................................533

B.2.1. Introduction...........................................................................................................................533

B.2.2. Weeds in Soybeans................................................................................................................533

B.2.3. Weed Management in Soybean...........................................................................................535

B.2.4. Herbicide-resistant Weeds in Soybean Production..........................................................544

B.2.4.1. Sustainable Use of Dicamba as a Weed Management Option in 

Soybean...................................................................................................................547

B.2.4.2. Stewardship of Dicamba Use on DT soybean.................................................551

B.2.4.3. Weed Control Recommendations......................................................................551

B.2.4.4. Dispersal of Technical and Stewardship Information ....................................551

B.2.4.5. Weed Resistance Management Practices ..........................................................553

B.2.4.6. Monsanto Weed Performance Evaluation and Weed Resistance 

Management Plan..................................................................................................553

B.2.5. Benefits of DT Soybean Production..................................................................................554

B.2.5.1. Overview ...............................................................................................................554

B.2.5.2. Benefits of the Weed Management System of Dicamba-GlyphosateTolerant Soybean ..................................................................................................557

B.2.5.3. Conclusion.............................................................................................................569
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B.3. DGT Cotton...........................................................................................................................................570

B.3.1. Introduction...........................................................................................................................570

B.3.2. Weeds in Cotton....................................................................................................................570

B.3.3. Weed Management in Cotton .............................................................................................572

B.3.4. Herbicide-resistant Weeds in Cotton Production ............................................................584

B.3.4.1. Sustainable Use of Dicamba as a Weed Management Option in 

Cotton.....................................................................................................................588

B.3.4.2. Stewardship of Dicamba Use on DGT Cotton...............................................592

B.3.4.3. Weed Control Recommendations......................................................................592

B.3.4.4. Dispersal of Technical and Stewardship Information ....................................592

B.3.4.5. Weed Resistance Management Practices ..........................................................594

B.3.4.6. Monsanto Weed Performance Evaluation and Weed Resistance 

Management Plan..................................................................................................594

B.3.5. Benefits of DGT Cotton Production.................................................................................595

B.3.5.1. Overview ...............................................................................................................595

B.3.5.2. Benefits of the Weed Management System of Dicamba, Glufosinate, 

and Glyphosate-Tolerant Cotton........................................................................598

B.3.5.3. Conclusion.............................................................................................................605
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Tables and Figures

Figure B-1. Weed Resistance to Various Herbicide Families1................................................................531

Table B-1. Common Weeds in Soybean Production: Midwest Region...............................................534

Table B-2. Common Weeds in Soybean Production: Southeast Region.............................................535

Table B-3. Common Weeds in Soybean Production: Eastern Coastal Region..................................535

Table B-4. Ten Most Widely Used Alternative Herbicides in U.S. Soybean Production in 

2012 ....................................................................................................................................................537

Table B-5. Dicamba and Alternative Registered Soybean Herbicides..................................................538

Table B-6. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide 

Products.............................................................................................................................................543

Table B-7. Known Weed Resistance in the Southern U.S.1...................................................................545

Table B-10. Management Recommendations for Control of Dicamba- and Other Synthetic 

Auxin-Resistant Weeds....................................................................................................................549

Table B-11. Anticipated Weed Management Recommendations for DT Soybean Combined 

with Glyphosate-Tolerant Soybean1..............................................................................................556

Table B-12. Common Broadleaf Weed Responses to Preplant Burndown Herbicides.....................565

Table B-13. Common Broadleaf Weed Responses to Dicamba Compared to Labeled 

Postemergence Herbicides in Soybean Production ....................................................................566

Table B-14. Common weeds in Cotton Production in the Southeast Region of the U.S.1,2...............570

Table B-15. Common weeds in Cotton Production in the Midsouth Region of the U.S.1,2.............571

Table B-16. Common weeds in Cotton Production in the Southwest Region of the U.S.1,2.............571

Table B-17. Common weeds in Cotton Production in the West Region of the U.S.1,2.......................572

Table B-18. Ten Most Widely Used Alternative Herbicides in U.S. Cotton Production ..................575

Table B-19. Dicamba and Alternative Registered Cotton Herbicides. .................................................576

Table B-20. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide 

Products.............................................................................................................................................582

Table B-20. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide 

Products.............................................................................................................................................582

Table B-21. Known Weed Resistance in the Southern U.S. in 20121...................................................587
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Table B-22. Deregulated Biotechnology-derived Cotton Products1.....................................................588

Table B-23. Management Recommendations for Control of Dicamba-, Glufosinate- and 

Other Selected Synthetic Auxin-Resistant Weeds.......................................................................590

Table B-24. Anticipated Weed Management Recommendations for DGT Cotton Combined 

with Glyphosate-Tolerant Cotton Systems for MO, AR, TN, AL, FL, GA, NC, SC, 

VA, LA, MS, eastern TXand CA.1,2...............................................................................................597

Table B-25. Anticipated Weed Management Recommendations for DGT Cotton Combined 

with Glyphosate-Tolerant Cotton Systems for western TX, NM, KS, OK, and AZ 1,2........597
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B.1. Introduction and Background on Herbicide Resistance

B.1.1. Overview of Herbicide Resistance

Herbicide resistance is “the inherited ability of a plant to survive and reproduce following exposure 

to a dose of herbicide normally lethal to the wild type” (WSSA 1998). In the mid-1950s, Harper 

(1957) theorized that annual, repeated use of any herbicide could lead to shifts in weed species 

composition within a crop-weed community. Similarly, Bandeen et al. (1982) suggested that a 

normal variability in response to herbicides exists among plant species and tolerance can increase 

with repeated use of a herbicide. To simplify, herbicide resistance in weeds is a result of natural 

selection. Plants of a given species are not all identical, but are made up of “biotypes” with various 

genetic traits. The use of any herbicide results in the potential for the selection of weed biotypes 

resistant to that herbicide, particularly when the herbicide is not used as part of a diversified weed 

management program. Within a weed species, individuals may possess an inherent ability to 

withstand the effects of a particular herbicide. Repeated use of that herbicide will expose the weed 

population to a “selection pressure,” which may lead to an increase in the number of surviving 

resistant individuals in the population (HRAC 2011). Where such repeated use of a herbicide over 

time occurs with no other appropriate herbicide or weed management practices, the resistant 

biotypes have the potential to become the dominant biotype in that weed community. 

As of April 2013, 400 herbicide-resistant weed biotypes have been reported to be resistant to 21 

different herbicide modes-of-action worldwide (Heap 2013b). Glyphosate-resistant weeds, which 

occur in certain areas of the U.S., account for approximately 6% of the herbicide-resistant biotypes 

while weeds resistant to herbicides that inhibit acetolactate synthase (ALS) account for 32% of the 

herbicide-resistant biotypes. Dicamba-resistant and glufosinate-resistant weeds account for <1% 

and 0.5% of resistant biotypes respectively (Heap 2012d; b; 2013b). 

For as long as herbicide resistance has been a known phenomenon, public-sector weed scientists, 

private-sector weed scientists, and growers have been identifying methods to address the problem. 

For instance, when a farmer uses multiple weed control tools, resistant biotypes generally will not 

become the dominant biotype within a population (Gunsolus 2008). By contrast, weed resistance is 

more likely to occur in areas where there is a sole reliance on a single herbicide used repeatedly over 

multiple crop generations for the management of a specific weed spectrum and where appropriate 

management practices are not utilized.

On agricultural land which contains a weed biotype that is resistant to a particular herbicide, the 

grower may use an alternate method of weed control. Management practices that can be used to 

retard the development of resistance include herbicide mixtures, herbicide rotation, and crop 

rotation. The Weed Science Society of America (WSSA) reports: “Weed scientists know that the 

best defense against weed resistance is to proactively use a combination of agronomic practices, 

including the judicious use of herbicides with alternative modes-of-action either concurrently or 

sequentially” (WSSA 2010). Studies have demonstrated that using the same combination of 

herbicides with multiple modes of action and overlapping effectiveness over multiple seasons is an 

effective way to proactively manage resistance (Beckie and Reboud 2009).

Due to the broad spectrum activity of glyphosate, it has been possible for growers to rely 

predominately on glyphosate for weed management and not utilize diversified weed management 

practices such as crop rotation, cultivation, or use of multiple herbicide modes of action; these 

practices have resulted in the selection of certain glyphosate-resistant weed biotypes. 
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Monsanto considers product stewardship to be a fundamental component of customer service and 

business practices. Stewardship of the dicamba and glyphosate herbicides to preserve their 

usefulness for growers is an important aspect of Monsanto’s stewardship commitment. Although 

herbicide resistance may eventually occur in weed species when an herbicide is widely used, 

resistance can be postponed, contained and managed through research, education and good 

management practices. These are the key elements of Monsanto’s approach to providing 

stewardship of dicamba used on DT soybean and DGT cotton integrated into the glyphosatetolerant soybean and cotton systems. Monsanto will invest in research, and grower/retailer 

education and training programs to provide information on best practices to manage dicamba weed 

resistance in soybean and cotton production. This appendix provides an overview of Monsanto’s 

approach to the development of best management practices to mitigate weed resistance. Monsanto 

works closely with weed scientists in academia and with other companies to research and develop 

best management practices and to uniformly communicate such practices to growers. Evidence of 

this cooperative effort is the recent development and posting of herbicide resistant training modules 

on the WSSA website (www.wssa.net) and the publication of guidelines by the Herbicide Resistance 

Action Committee (HRAC) on their website (www.hracglobal.com).

B.1.2. The Herbicide Dicamba

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is classified as a benzoic acid herbicide belonging to 

the synthetic auxin group of herbicides (HRAC, 2010). The herbicides in this group act as growth 

regulators similar to endogenous indole acetic acid (IAA), but are structurally diverse. The synthetic 

auxin group includes five chemical families (benzoic acid, pyridine-carboxylic acid, quinoline 

carboxylic acid, phenoxy-carboxylic acid and a separate class which includes one herbicide, 

benazolin ethyl). In addition to dicamba, specific herbicides in this group include 2,4-D, 2,4-DB, 

mecoprop, MCPA, clopyralid, picloram, quinclorac and several other active ingredients. Dicamba 

and other synthetic auxin herbicides are classified in Herbicide Group 4 by the WSSA (HRAC, 

2009). Most herbicides in this group are active on broadleaf weeds only, but a few have significant 

activity on grasses, e.g., quinclorac. The specific site of action among the different chemistry families 

may be different. Dicamba provides preemergence and postemergence control of over 95 annual 

and biennial broadleaf weed species and control or suppression of over 100 perennial broadleaf and 

woody species103. Dicamba is not active on grass weeds and is often used in combination with other 

herbicides to provide broad spectrum weed control.

Dicamba was commercialized in the U.S. for agricultural use in 1967 and is currently labeled for 

preemergence and/or postemergence weed control in corn, soybean, cotton, sorghum, small grains 

(wheat, barley and oats), millet, pasture, rangeland, asparagus, sugarcane, turf, grass grown for seed, 

conservation reserve program land, and fallow cropland (U.S. EPA, 2009). Dicamba is sold as a 

standalone formulation which can be tank mixed with one or more active ingredients depending 

upon the crop and the weed spectrum. Dicamba is also sold as a premix formulation with other 

herbicides. 

 

103 Clarity product label http://www.cdms.net/LDat/ld797002.pdf 
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Dicamba kills plants by mimicking naturally-occurring plant growth hormones called auxins, thereby 

destroying tissue through uncontrolled cell division and growth (Ahrens, 1994). Ahrens (1994) 

further states that dicamba in some cases has been found to affect cell wall integrity and nucleic acid 

metabolism, whereas in other cases it has been found to increase cell wall permeability, leading to 

cell enlargement. At low concentrations, dicamba has been found to increase synthesis of DNA, 

RNA, and proteins, resulting in altered cell division and growth. At high concentrations, inhibition 

of cell division and growth occur. In general, dicamba and other synthetic auxin herbicides have 

been found to affect multiple plant physiological systems. The molecular mechanism of auxin 

action is still not known in detail nor completely understood (Devine et al., 1993, Jugulam et al. 

2011). However, Grossmann (2010), in a review of auxin herbicides, outlined a proposed 

mechanism and mode-of-action for auxin herbicides and IAA at supraoptimal endogenous 

concentrations in dicot plant species. The proposal was based upon recent identification of 

receptors for auxins and hormone interaction in signaling between auxin, ethylene and the 

upregulations of abscisic acid biosynthesis, which would account for a large part of the various 

auxin-herbicide-mediated responses that are seen in sensitive dicots. In addition, research has 

indicated that there is a high level of redundancy in auxin receptors, which may account for the lack 

of development of widespread resistance to this herbicide group (Walsh et al., 2006).

Dicamba is taken up by plants through the roots, stems, and foliage (Ahrens, 1994; NPIC, 2002). 

Dicamba translocates to all plant tissues but accumulates in growing tissues. Translocation of 

dicamba is typically slower in tolerant plants such as grasses as compared to broadleaf plants. 

Dicamba has a relatively low soil-binding coefficient. 

B.1.3. The Herbicide Glufosinate

Glufosinate [2-Amino-4-(hydroxymethylphosphinyl) butanoic acid] is classified as a phosphinic acid 

herbicide belonging to the glutamine synthetase inhibitor group of herbicides (HRAC, 2010). 

Bialaphos is the only other active ingredient belonging to the phosphinic acid chemical family. 

Glufosinate and bialaphos are classified in Herbicide Group 10 by the WSSA (HRAC, 2010). 

Glufosinate provides postemergence control of over 90 annual grass and broadleaf weed species and 

25 biennial and perennial grass and broadleaf weed species.

Glufosinate was first approved for use in the U.S. in 1994 (U.S. EPA, 2008) and is currently labeled 

for non-crop uses, preplant burndown to glufosinate-tolerant and nontolerant crops and/or in-crop 

postemergence weed control in glufosinate-tolerant canola, corn, cotton, and soybean, (Bayer 

CropScience, 2011). Glufosinate is sold as standalone formulation which can be tank mixed with 

one or more active ingredients depending upon the crop and the weed spectrum.

Glufosinate acts in plants by inhibiting the enzyme glutamine synthase, causing a toxic buildup of 

ammonia within the treated plant (Bayer, 2010). Glufosinate is a nonselective herbicide and has no 

residual activity. This herbicide has a different mode-of-action than the other major herbicides used 

in cotton.

B.1.4. Herbicide-Resistant Weeds and Resistance Management Strategies

The development of herbicide-resistant weeds is not a new phenomena and resistance is not limited 

to certain select herbicides. In 1957, the first U.S. herbicide-resistant weed, a spreading dayflower 

biotype resistant to 2,4-D, was identified in Hawaii (Heap, 2010). Currently, there are 73 individual 

weed species that have known herbicide-resistant biotypes to one or more herbicides in the U.S. 
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For example, there are 42 weed species resistant to ALS herbicides, 15 to ACCase inhibitors, 24 to 

photosystem II inhibitors, and 10 to glycine herbicides (Heap, 2010). Growers have been managing 

herbicide-resistant weeds for decades with the use of alternative herbicides and/or cultural methods 

such as tillage or crop rotation. 

The occurrence of an herbicide-resistant weed biotype does not end the useful lifespan or preclude 

the effective use of the herbicide in question as part of an overall diversified weed management

system. The three herbicide classes with the highest number of resistant species, ALS, ACCase and 

triazine herbicides, are still effectively used by growers today. 

It is important to distinguish herbicide resistance from herbicide tolerance. A herbicide-resistant 

weed is one in which there is an inherited ability of a plant to survive and reproduce following 

exposure to a dose of herbicide normally lethal to the wild type (WSSA, 2012). A herbicide-tolerant 

weed species is one that is naturally tolerant to a herbicide; for example, a grass species is not killed 

by the application of a broadleaf herbicide (WSSA, 2012). Furthermore, certain weed species, while 

neither resistant nor tolerant, are inherently difficult to control with a particular herbicide, requiring 

more careful herbicide use and weed management practices.

Since the first confirmed cases of herbicide resistance, research has been directed at determining 

which practices are best for managing existing resistance situations and how best to reduce the 

development of herbicide resistance. Resistant management practices most often recommended by 

university/Cooperative Extension Service (CES) and industry are: 1) use of multiple herbicide 

modes-of-action in mixture, sequence, or in rotation, 2) crop rotation, 3) use of cultural control 

measures such as tillage and time of planting, and 4) use of the labeled herbicide rate at the 

recommended timing of application (Gressel and Segel, 1990; Beckie, 2006). Recent research by 

Beckie and Reboud (2009) indicates that in some cases herbicide mixtures offer a better 

management option than rotating herbicides. Simultaneously using two herbicides with different 

modes-of-action significantly reduce the probability of weeds developing resistance to either or both 

herbicides (Beckie and Reboud, 2009). Crop rotation can also be an effective method for resistance 

management due to the fact that it fosters the use of additional herbicide modes-of-action and, 

potentially, use of additional cultural practices to manage weeds over time. The use of multiple 

methods of weed control in a single location is the technical basis for developing management 

programs to mitigate the potential for development of resistance. This general concept has been 

referred to as applying “diversity” within a crop or across a crop rotation (Beckie, 2006; Powles, 

2008).

It is generally accepted that conservation tillage practices (minimum-till and no-till) create 

environments where herbicide resistance is more likely to develop (Beckie, 2006). This is probably 

due to selection pressure put on weeds by herbicides in these environments and the absence of 

tillage as a cultural weed management practice to supplement herbicide use. However, this is not 

always the case. Legere et al. (2000) found that an increase in the use of ACCase inhibitors in a 

conservation tillage system (e.g. aryloxyphenosy propionates and phenylpyrazolines herbicide 

families) did not result in an increased incidence of wild oat populations resistant to ACCase 

inhibitors. Thus, conservation tillage practices should not be considered a primary contributing 

factor to the development of resistance in all cases

B.1.5. Characteristics of Herbicides and Herbicide Use Influencing Resistance
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While the incidence of weed resistance is often associated with repeated applications of an herbicide, 

the actual probability for the development of resistant populations is related, in part, to the specific 

herbicide active ingredient, chemical family and the herbicide group. Some herbicides are more 

prone to the development of resistance than others (Heap, 2010). The graph in Figure A-1 

illustrates the global instances of weed resistance to various herbicide groups. The different slopes 

of observed resistance are largely due to the factors described above, which relate to the specific 

herbicide active ingredient as well as to the group and herbicide family and its function.

Figure B-1. Weed Resistance to Various Herbicide Families1

As can be seen in Figure A-1, weed resistance to the synthetic auxin group of herbicides has been 

slower to develop than for other herbicide groups even though these were the first synthetic 

herbicides discovered and used commercially. Possible reasons for this are discussed below.

1Global number of resistant biotypes

B.1.6. Mechanisms of Resistance and Inheritance of Resistance

To date, the three known basic mechanisms by which weed species develop resistance to a herbicide 

have been identified: 1) target site alteration (target site), 2) enhanced metabolism of the herbicides 

(metabolism), and 3) reduced absorption and/or translocation of the herbicide such that the 

herbicide does not get to the site of action within the plant cell (exclusion) (Sammons et al., 2007).

Herbicide resistance via target site alteration is the most common resistance mechanism among the 

various herbicide groups and chemical families. It has been found that a target site mechanism is the 

most common mechanism for ALS inhibitors, ACCase inhibitors, and triazines, but is less common 

for other herbicide groups, such as glycines (Powles and Yu, 2010). The most common type of 

target site alteration is one where amino acid substitution(s) in the protein that is the target of the 
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herbicide occurs such that the alteration prevents the binding of the herbicide to the protein and as a 

result the activity of the targeted protein is not altered and the plant grows normally. 

In the case of synthetic auxin herbicides, resistance has been speculated to be due to mutation(s) in 

genes encoding an auxin-binding protein causing reduced herbicide binding (Zheng and Hall, 2001; 

Goss and Dyer, 2003). In several studies, differential herbicide absorption, translocation, and 

metabolism were ruled out as possible mechanisms of resistance in kochia (Cranston et al., 2001) 

and in wild mustard (Zheng and Hall, 2001). However, current research has not presented 

convincing evidence for a single mechanism of resistance and this inability to elucidate the 

mechanism of resistance may be due to a lack of thorough understanding of auxin mechanism of 

activity (Jasieniuk et al., 1996). Walsh et al. (2006) identified seven alleles at two distinct genetic loci 

that conferred significant resistance to picolinate auxins (picloram) in Arabidopsis, yet had minimal 

cross-resistance to 2,4 D and IAA. 

Multiple mechanisms for inheritance of dicamba resistance have been reported in the literature. 

Jasieniuk et al. (1995) reported results indicating that inheritance of dicamba resistance in wild 

mustard is determined by a single, completely dominant nuclear allele. However, Cranston et al. 

(2001) reported results indicating that dicamba resistance in kochia is determined by a quantitative 

trait (two or more genes). 

In summary, the slow development of weed resistance to synthetic auxin herbicides may in part be 

due to their proposed multiple sites of physiological action in plants (Jasieniuk et al., 1996) and to 

the possibility that inheritance, at least in some species, is determined by a quantitative trait 

(Cranston et al., 2001). 

B.1.7. Weeds Resistant to Dicamba and Glufosinate

To date, there are four species with known resistant biotypes to dicamba in the U.S./Canada after 

over 40 years of use: common hempnettle, kochia, prickly lettuce, and wild mustard (Heap, 2012a). 

Additionally, a population of common lambsquarters has been confirmed to be resistant in New 

Zealand, for a total of five species worldwide with confirmed resistant biotypes to dicamba. For the 

synthetic auxin group of herbicides, there exist a total of 29 species globally with biotypes having 

confirmed resistance to at least one member of this group, but only nine species in the U.S. and four 

species in Canada (Heap, 2012a). Except for two (wild carrot in OH and MI, and waterhemp in 

NE), all of these populations are found in western states or western Canadian provinces. In some 

weed species, cross-resistance between different herbicides within the auxin group has been 

confirmed (plant cross-resistance to another herbicide as a result of exposure to a similarly acting 

herbicide). Therefore, consideration has to be given to the possibility that dicamba resistance could 

extend to some of the other broadleaf species listed as resistant to other synthetic auxin herbicides 

(Cranston et al., 2001; Jasieniuk et al., 1995; Miller et al., 2001). However, because of differences in 

sites of action among the chemistry families within this group (i.e., benzoic acids compared to 

pyridine-carboxylic acids) cross-resistance between the herbicide groups is not a certainty, and it can 

be mitigated with diversified weed management practices (Monaco et al., 2002).

With the introduction of DT soybean and DGT cotton into glyphosate-tolerant soybean and cotton 

systems, where dicamba will be applied in combination with glyphosate (and glufosinate in the case 

of cotton), it is important to note that kochia is the only broadleaf species with resistant biotypes to 

either synthetic auxins or glyphosate. However, there are no known kochia biotypes resistant to both 

of these herbicides or resistant to glufosinate. In addition, the evolution of a dicamba-glyphosate-
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resistant biotype is unlikely because dicamba, glyphosate, and/or glufosinate (for DGT cotton only), 

each with a distinct mode-of-action, will likely be applied in the same season to DT soybean or 

DGT cotton in the glyphosate-tolerant soybean and cotton systems. If populations with resistance 

to both glyphosate and dicamba herbicides were to occur, there are other herbicide options for 

managing the weed in soybean and cotton (e.g., glufosinate, clomazone and flumioxazin) and in its 

rotational crops (e.g., atrazine and isoxaflutole in corn) (See Table B-10). The glyphosate-resistant 

kochia biotype is also found in western soybean growing areas, but it is isolated to small areas where 

soybean is grown in limited acreage. The glyphosate-resistant kochia biotype may be found in 

western cotton growing areas of Texas and Oklahoma.

To date, there are two weed species with confirmed resistance to glufosinate: goosegrass in Malaysia 

and Italian ryegress in Oregon, U.S. (Heap, 2012d). In the case of goosegrass, the resistant 

populations evolved due to use of glufosinate in a rubber plantation (Seng et al, 2010). In the case of 

Italian ryegrass, the resistance was actually discovered in populations exposed to glyphosate that 

evolved resistance to glyphosate and which had not been exposed to glufosinate, exemplifying a case 

of cross-resistance (Avila-Garcia and Mallory-Smith, 2011). No resistance in a broadleaf species has 

been found to date.

Italian ryegrass may require special consideration when designing appropriate management programs 

because of the potential for cross-resistance between glyphosate and glufosinate to exist. AvilaGarcia and Mallory-Smith (2011) demonstrated the only case of glufosinate cross-resistance, which 

developed when the populations evolved resistance to glyphosate. It is not known if the reverse is 

true. Where there are known glyphosate resistant ryegrass populations Monsanto will recommend 

not using glufosinate to control these populations. Likewise, dicamba will not be an option, since it 

does not control grasses such as ryegrass. Other herbicides such as those in the ACCase or ALS 

classes will be recommended. It is important to note that ryegrass is generally a weed target in 

preplant burndown applications and not in the cotton crop itself because of the biology of the 

species.

B.2. DT Soybean

B.2.1. Introduction

This section addresses weeds and weed management in soybean production, followed by a 

discussion of herbicide-resistant weeds and the benefits of DT soybean production. 

B.2.2. Weeds in Soybeans

Annual weeds are perceived to be the greatest pest problem in soybean production, followed by 

perennial weeds (Aref and Pike 1998). Weed control in soybean is essential to optimizing yields 

because weeds compete with soybean for light, nutrients, and soil moisture. Weeds can also harbor 

insects and diseases, and can interfere with harvest, causing extra wear on harvest equipment 

(Pedersen 2008b). 

Foxtail spp. (Setaria spp.), pigweed (Amaranthus spp.), velvetleaf (Abutilon theophrasti), lambsquarters 

(Chenopodium album), and cocklebur (Xanthium strumarium) are common weeds in Midwest corn and 

soybean fields. However, growers in Indiana consider giant ragweed (Ambrosia artemisiifolia), 

lambsquarters, Canada thistle (Cirsium arvense), cocklebur, and velvetleaf to be the top five most 

problematic weeds in corn and soybean because of the difficulty controlling these weeds (Nice and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 534 of 946

Johnson, 2005). Giant and/or common ragweed are also common and problematic in Minnesota, 

Missouri, Arkansas, Wisconsin and Illinois (Iowa State University 2003; Boerboom 2006; Anderson 

2012). In a 2005-2006 survey of 1,200 growers of glyphosate-tolerant crops (soybean, corn and 

cotton) in six Midwestern and southern states, growers in Illinois and Iowa, the two leading 

soybean-producing states, most frequently named common waterhemp (Amaranthus tuberculatus) as 

most problematic (Kruger et al., 2009). Waterhemp is also a common problem weed in Minnesota, 

Indiana, Nebraska, Wisconsin and Missouri (Kruger et al., 2009; ISU, 2003; Boerboom, 2006; 

Boerboom and Owen, 2006; Legleiter et al., 2009; Anderson, 2012). Horseweed (Conyza 

canadensis, also called marestail) is problematic in Ohio, Arkansas, Tennessee, Kansas, Wisconsin 

and Illinois (Peterson and Shoup, 2012; Boerboom, 2006; Mueller et al., 2005). 

Tables B-1 through B-3 summarize the most common weeds for each of the three major soybean 

growing regions (Midwest, Southeast and Eastern Coastal).

Table B-1. Common Weeds in Soybean Production: Midwest Region

Foxtail spp. (12)1 Ragweed, giant (3) Dandelion (1)

Pigweed spp. (11) Shattercane (3) Johnson grass (1)

Velvetleaf (11) Quackgrass (3) Milkweed, honeyvine (1)

Lambsquarters (10) Buckwheat, wild (2) Nightshade, hairy (1)

Cocklebur (9) Crabgrass spp. (2) Oats, wild (1)

Ragweed, common (7) Kochia (2) Pokeweed, common (1)

Smartweed spp. (6) Mustard, wild (2) Prickly sida (1)

Morningglory spp. (5) Nightshade, Eastern black (2) Proso millet, wild (1)

Sunflower, spp. (5) Palmer pigweed (2) Sandbur, field (1)

Waterhemp spp. (5) Canada thistle (1) Venice mallow (1)

Horseweed (marestail) (3) Chickweed (1) Volunteer cereal (1)

Panicum, fall (3) Cupgrass, woolly (1) Volunteer corn (1)

1 Number provided in parenthesis is the number of states out of the thirteen total states in the Midwest region 

reporting each weed as a common weed. 

Sources: 

IL: University of Illinois (2002) and Aaron Hager, Extension Weed Specialist, University of Illinois -

Personal Communication (2006).

IN: 2003-2005 Statewide Purdue Horseweed Weed Survey, Special database query and personal 

communication (2006), Bill Johnson, Extension Weed Specialist, Purdue University.

IA, MN, OH, WI: WSSA, 1992. 

KS: Dallas Petersen, Extension Weed Specialist, Kansas State - Personal communication (2006).

KY, MO: Webster et al., 2005.

MI: Davis et al., 2005. 

NE: Alex Martin, Extension Weed Specialist, University of Nebraska – Personal communication 

(2006).

ND: Zollinger, 2000.

SD: Michael Moechnig, Extension Weed Specialist, South Dakota State University – Personal 

communication (2006).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 535 of 946

Table B-2. Common Weeds in Soybean Production: Southeast Region

Morningglory spp. (8)1 Goosegrass (3) Cutleaf evening-primrose (1)

Crabgrass spp. (6) Johnsongrass (3) Groundcherry (1)

Prickly sida (6) Ragweed, common (3) Henbit (1)

Nutsedge spp. (6) Cocklebur (2) Lambsquarters (1)

Sicklepod (5) Florida beggarweed (2) Ragweed, giant (1)

Signalgrass, broadleaf (5) Hemp sesbania (2) Smartweed (1)

Palmer pigweed (4) Horseweed (marestail) (2) Spurge, nodding/hyssop (1)

Pigweed spp. (4) Texas millet (2) Spurge, Prostrate (1)

Barnyard grass (3) Browntop millet (1) Tropic croton (1)

Florida pusely (3) Copperleaf, hophorn (1)

1 Number provided in parenthesis is the number of states out of the eight total states in the Southeast region 

reporting each weed as a common weed. 

Sources:

AL, AR, GA, LA, NC, SC: Webster et al., 2009. 

MS, TN: Webster et al., 2005.

Table B-3. Common Weeds in Soybean Production: Eastern Coastal Region

Foxtail spp. (6)1 Morningglory spp. (4) Dandelion (1)

Ragweed, common (6) Panicum, fall (4) Goosegrass (1)

Velvetleaf (6) Crabgrass spp. (3) Johnson grass (1)

Lambsquarters (5) Nutsedge spp. (3) Nightshade, Eastern black (1)

Pigweed spp. (5) Quackgrass (2) Prickly sida (1)

Cocklebur (4) Canada thistle (1) Shattercane (1)

Jimson weed (4) Burcucumber (1) Smartweed spp. (1)

1 Number provided in parenthesis is the number of states out of the six total states in the Eastern Coastal 

region reporting each weed as a common weed. Data were not available for DE in soybean. 

Sources:

DE, MD, NJ, PA: WSSA, 1992. 

NY: Russell Hahn, Extension Weed Specialist, Cornell University – Personal Communication (2006). 

VA: Webster et al., 2009.

B.2.3. Weed Management in Soybean

The factors that affect a potential yield loss in soybean from weed competition are the weed species, 

weed density, and the duration of the competition. When weeds are left to compete with soybean 

for the entire growing season, yield losses can exceed 75% (Dalley et al. 2001). Generally, the 

competition between crops and weeds increases with increasing weed density. The time period that 

weeds compete with the soybean crop influences the level of yield loss. In general, the later the 

weeds emerge, the less impact the weeds will have on yield. Soybean plants withstand early-season 

weed competition longer than corn, and the canopy generally closes earlier in soybean than corn 

(i.e., plants in adjacent rows grow to a sufficient size such that their foliage touches between the 

rows blocking the sunlight from reaching the ground). In addition, canopy closure is much sooner 

when soybean is planted in narrow rows. 

The most effective weed management programs in soybean use a combination of cultural, 

mechanical, and/or herbicide control practices, hereafter called diversified weed management 

practices, instead of relying on one particular method of weed control (Beckie et al. 2011; University 

of California 2009; Vargas et al. 1996). Herbicide application practices that are compatible with 

diversified weed management practices include the use of several herbicides with different modes of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 536 of 946

action, either within or across seasons, applying herbicides at the labeled rate at the correct timing, 

and proper application of the herbicide. Cultural and mechanical practices can also be important 

components of an effective diversified weed management program (Ashigh et al. 2012). Cultural 

practices such as crop rotation, narrow row spacing and planting date are a few of the crop 

management practices that are implemented to provide the crop with a competitive edge over 

weeds. Mechanical methods of weed control, including tillage, have been used for centuries to 

control weeds in crop production. Spring or fall preplant tillage and in-crop shallow cultivation can 

effectively reduce the competitive ability of weeds by burying the plants, disturbing or weakening 

their root systems, or causing sufficient physical injury to kill the plants. A consequence of in-crop 

cultivation for weed control is that it can injure crop roots and cause moisture loss. The planting of 

winter cover crops is another cultural practice that can also be utilized. The planting of cover crops, 

such as grasses, legumes or small grains, can protect and improve soil quality, help reduce erosion, 

and can serve as surface mulch in no-till cropping practices (Mannering et al, 2007). However the 

planting of a cover crop incurs additional costs to the grower and therefore cover crops are typically 

not a major weed management practice in major soybean growing areas (Singer, 2006). 

The use of herbicides has become an important part of managing weeds in soybean. Approximately 

98 percent of the soybean acreage received an herbicide application in 2012 (USDA-NASS, 2013a). 

The availability of herbicide-tolerant soybean products is an important aspect of weed management 

in U.S. soybean production. Herbicide-tolerant soybean was introduced to provide growers with 

additional options by improving crop safety (no herbicide damage to the crop) and improving weed 

control. In 2013, 93% of the U.S. soybean crop was herbicide-tolerant (USDA-NASS 2013e); 

almost all is glyphosate-tolerant. As a result, glyphosate is the most widely used herbicide, being 

applied on 98 percent of the soybean acreage in 2012, including for preplant burndown and 

postemergence in crop applications (USDA-NASS 2013a).

Over 35 different herbicide active ingredients are registered and available for use by soybean 

growers to control weeds. The ten most widely used alternative herbicides in soybean are listed in 

Table B-4. Alternative soybean herbicides use has almost doubled between 2009 and 2012. 

Integration of DT soybean into the glyphosate-tolerant soybean system and the subsequent use of 

dicamba will result in the displacement of some currently used, or foreseeable future use herbicides 

(see Appendix A for more details), and therefore the properties of these alternative herbicides are 

summarized in this section to provide a baseline for comparison to dicamba use on DT soybean.

Herbicide weed control programs in conventional soybean consist of preemergence herbicides used 

alone or in mixtures. Mixtures of two preemergence herbicides are used to broaden the spectrum of 

control to both grasses and broadleaf weed species. Preemergence herbicides are followed by 

postemergence applications to control weeds that emerge later in the crop. Total postemergence 

weed control programs were seldom used in conventional soybean prior to 1995. Prior to 

glyphosate-tolerant soybean, soybean planted in a no-till system would receive a preplant burndown 

herbicide application for broad-spectrum control of existing weeds at time of planting, followed by 

different soil residual herbicides at planting and possibly still other herbicides applied postemergence 

to the crop and the weeds. In conventional soybeans, the typical herbicide program consisted of 

multiple soil residual herbicides applied preemergence to the crop and weeds and, possibly, other 

herbicides applied postemergence to the crop and weeds. Therefore, multiple herbicides and/or 

multiple applications were generally used in conventional and no-till non-glyphosate-tolerant 

soybean. The average number of herbicide applications per acre in soybean rose from 1.5 in 1990 to 

1.7 applications in 1995, reflecting the use of at-plant and postemergence applications or two 

postemergence applications (Gianessi et al., 2002).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 537 of 946

Table B-4. Ten Most Widely Used Alternative Herbicides in U.S. Soybean Production in 

2012

Herbicide Treated Acres 

(millions)1

Pounds Applied

(millions)1

2,4-D (acid, salts, and esters, 

combined)

11.58 6.02

Flumioxazin 8.49 1.56

Imazethapyr 3.86 1.35

cloransulam-methyl 3.09 0.60

chlorimuron-ethyl 8.49 0.52

Fomesafen 6.18 0.22

Clethodim 6.95 0.19

pendimethalin 1.54 0.08

Tribenuron 0.77 0.04

flumiclorac-pentyl 0.77 0.01

1 USDA-NASS, 2013

Selective herbicides are designed to kill specific types of plants, usually grasses or broadleaf weeds, 

and have proven effective to reduce in-crop tillage or cultivation to control weeds in soybean 

production. The development of selective herbicides has progressed since the introduction of the 

first herbicide (2,4-D) for weed control in corn in early 1940s. Although the primary purpose of 

tillage is for seedbed preparation, tillage still is used to supplement weed control with selective 

herbicides in soybean production. 

Table B-5 lists the most-widely used soybean herbicide products that contain active ingredients 

(a.i.s). Table B-5 also summarizes some key information about the alternative herbicide products 

that are evaluated in this Environmental Report, such as signal word, re-entry interval, use rates, and 

label warnings or special directions. 

Table B-6 lists the eighteen active ingredients that make up the products in Table B-5. 2,4-D, being 

used primarily as a pre-plant application, is the most widely-used herbicide in this alternate herbicide 

list, representing about 10% of treated acres; whereas acifluorfen, carfentrazone-ethyl, and flufenacet 

are the least used among these, representing <0.5% of treated acres. Mesotrione has not been used 

in soybean production previously; the use on soybean was only recently registered by the EPA 

(2009d). Table B-6 also lists general regulatory information about each herbicide. Note that only 

paraquat is classified as a Restricted Use pesticide among this group, on the basis of acute 

toxicological concern.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 538 of 946

Table B-5. Dicamba and Alternative Registered Soybean Herbicides

Brand

(U.S. EPA 

Reg. No.) Active Ingredient

Signal 

Word1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean 

lb/a 

(season)

Label Warnings or 

Special Directions4

Clarity (7969-

137)

Dicamba Caution 4.0 lb a.e./gal 24 hr 1.0 1 2.0 1 Known to leach; 50-foot 

buffer to wells; Runoff 

advisory; Drift advisory; 

State-specific limitations; 

Soil type limitations; 

Maximum crop rotation 

interval 3 – 6 months.

Aim® (279-

3241)

CarfentrazoneethylCaution 2 lb/gal 12 hr 0.008 5 0.023 “toxic to fish”;”toxic to 

algae”; V3 - V10; do not 

feed foliage; some burn 

injury

Authority®

First DF 

(279-3246)

Sulfentrazone Caution 0.62 lb/lb 12 hr 0.31 0.31 “known to leach”; “toxic 

to marine / estuarine 

invertebrates”;65-day 

PHI; crop rotation 

restrictions, up to 30 mts; 

soil O.M. limits (sands 

<1% organic matter)

Cloransulammethyl0.08 lb/lb 0.04 0.04

Authority 

MTZ (279-

3340)

Sulfentrazone Caution 0.18 lb/lb 12 hr 0.028 0.046 “known to leach”; “toxic 

to marine / estuarine 

invertebrates”; 120-day 

PHI (not Over The Top); 

sensitive varieties, injury 

possible

Metribuzin 0.27 lb/lb 0.042 0.07

Basagran®

(7969-45)

Bentazon Caution 4 lb/gal 48 hr 1 2 “known to leach”;30-day 

PHI for feeding treated 

forage and hay; minor 

injury

Butoxone®

7500 (71368-

49)

2,4-DB Caution 0.75 lb/lb 48 hr 0.375 soil type limits

Butyrac® 200 

(42750-38)

2,4-DB DMA salt Danger 2 lb/gal 48 hr 0.4 0.4 “toxic to fish”;60-day 

PHI; injury may occur, 

especially with tank 

mixtures

Cadet® (279-

3338)

Fluthiacet-methyl Warning 0.91 lb/gal 12 hr 0.0065 0.009 do not feed foliage; minor 

injury

Callisto®

(100-1131) 

Mesotrione Caution 4 lb/gal 12 hr 0.1875 0.1875 “high potential for 

runoff”; crop rotation 

restrictions up to 18 mts; 

“transient bleaching” may 

occur; pre-emergence use 

only, no in crop use
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 539 of 946

Table B-5 (continued). Dicamba and Alternative Registered Soybean Herbicides

Brand

(U.S. EPA 

Reg. No.)

Active 

Ingredient

Signal 

Word1

Active Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. Soybean 

lb/a (single 

treatment)3

Max. 

Soybean 

lb/a 

(season)

Label Warnings or 

Special Directions4

Classic® (352-

436)

ChlorimuronethylCaution 0.75 lb/lb 12 hr 0.14 0.14 6 60-day PHI; crop 

rotation restrictions 

up to 30 mts and 

complicated 

description of 3 

different intervals 

specific to US 

regions and soil pH; 

do not feed foliage; 

soil type limits; 

“temporary leaf 

yellowing”

Cobra® (59369-

34)

Lactofen Danger 2 lb/gal 12 hr 0.2 0.4 6 “toxic to fish”; do 

not apply past 

soybean growth 

stage R6/45-day 

PHI; minor injury

Extreme ®

(241-405)

Imazethapyr Warning 0.17 lb/gal 48 hr 0.064 6 0.064 6 “properties & 

characteristics 

associated with 

chemicals detected in 

ground water”; crop 

rotation limits

GlyphosateIPA2 lb/gal 0.75 0.75

FirstRate 

(62719-275)

CloransulammethylCaution 0.84 lb/lb 12 hr 0.04 0.055 65-day PHI; crop 

rotation restrictions 

up to 30 mts; soil 

types; 14-day forage 

and hay feeding 

restriction

Flexstar ®

(100-1101)

Fomesafen Warning 1.88 lb/gal 24 hr 0.35 0.375 6 “cause tumors”; 

“known to leach”; 

45-day PHI; do not 

feed foliage; crop 

rotation limits

Gangster ® Copack (59639-

131)

Flumioxazin Caution 51% 12 hr 0.096 0.096 “toxic to aquatic 

invertebrates”; 

“Preemergent only”; 

“properties & 

characteristics 

Associated with 

chemicals detected in 

ground water”; 

“toxic to 

invertebrates.”

Cloransulammethyl84% 0.032 0.032

Gramaoxone 

Inteon ® (100-

1217)

Paraquat 

dichloride

Danger 2 lb/gal (cation 

basis)

12 hr 1.5 2.9 “toxic to wildlife”; 

Restricted Use; no 

Over-the-Top use
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 540 of 946

Table B-5 (continued). Dicamba and Alternative Registered Soybean Herbicides 

Brand 

(U.S. EPA 

Reg. No.)

Active 

Ingredient

Signal 

Word1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. 

Soybean 

lb/a (single 

treatment)3

Max. 

Soybean 

lb/a 

(season)

Label Warnings or Special 

Directions4

Ignite®

(264-829)

GlufosinateammoniumWarning 2.34 lb/gal 12 hr 0.66 0.8 “runoff potential”; “toxic to 

vascular plants”; 70-day PHI; 

some crop rotation limits up to 

180 days; only Over-the-Top to 

Liberty Link soybean

Liberty®

(264-660)

GlufosinateammoniumWarning 1.67 lb/gal 12 hr 0.44 0.8 “runoff potential”; “toxic to 

vascular plants”; 70-day PHI; 

do not feed foliage; crop 

rotation limits up to 120 days;

Phoenix®

(59639-

118)

Lactofen Caution 2 lb/gal 12 hr 0.3 0.4 6 “toxic to fish”; Do not apply 

past crop growth stage R6 / 

45-day PHI; minor injury

Pursuit®

(241-310)

Imazethapyr Caution 2 lb/gal 4 hr 0.063 0.063 “properties & characteristics 

associated with chemicals 

detected in ground water”; 85-

day PHI; do not feed forage 

and hay

Pursuit®

Plus 

(241-331)

Pendimethalin Caution 2.7 lb/gal 24 hr 0.84 0.84 “properties & characteristics 

associated with chemicals 

detected in ground water”; 

“toxic to fish”; 85-day PHI; 

crop rotation limits up to 40 

months

Imazethapyr 0.2 lb/gal 0.063 0.063

Raptor ®

(241-379)

ImazamoxammoniumCaution 1 lb/gal 4 hr 0.04 0.04 “phytotoxic to all plants”; 

plantback / crop rotation limits 

up to 26 months, two regions 

with complicated warnings
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 541 of 946

Table B-5 (continued). Dicamba and Alternative Registered Soybean Herbicides 

Brand

(U.S. EPA 

Reg. No.)

Active 

Ingredient

Signal 

Word 1

Active 

Ingredient 

Content

Reentry 

Interval 

(REI)2

Max. 

Soybean 

lb/a 

(single 

treatment)3

Max. 

Soybean 

lb/a 

(season)

Label Warnings or 

Special Directions4

Reflex® (100-

993)

Fomesafen Danger 2 lb/gal 24 hr 0.375 0.375 6 “known to leach”; 45-day 

PHI; crop rotation limits 

up to 18 mts; minor injury, 

significant geographical 

restrictions (5 regions each 

with different rate 

structure)

Resource®

(59639-82)

Flumiclorac-pentyl Warning 0.86 lb/gal 12 hr 0.081 0.11 “toxic to shrimp”; 60-day 

PHI; do not feed forage or 

hay to livestock; temporary 

spotting or burn to soybean

Scepter ®70 

DG (241-306)

Imazaquin Caution 0.7 lb/lb 12 hr 0.123 0.123 6 “properties & 

characteristics associated 

with chemicals detected in 

ground water”; 90-day PHI; 

do not feed forage or hay 

to livestock; crop rotation 

limits up to 40 mts; 

regional limitations (3 

regions)

Sencor® (DF 

75%) (264-

738)

Metribuzin Caution 0.75lb/lb 12 hr 0.66 6 1.3 6 “can seep or leach”; 70-day 

grain PHI; 40-day PHI on 

feeding forage to livestock; 

no Over-the-Top 

application, directed spray 

OK; injury in high pH or 

low O.M. soils or on 

certain crop varieties, crop 

rotation limits up to 18 mts

Synchrony®

XP (352-648)

Thifensulfuron Caution 0.069 lb/lb 12 hr 0.013 0.013 45-day planting restriction 

applied prior to soybean 

planting/emergence; 60-day 

PHI; complicated crop 

rotation restrictions (3 

regions, 4 intervals) with 

limits up to 30 mts; do not 

feed forage or hay to 

livestock; soil types; injury 

if adjuvants or tank mixed

UltraBlazer 

(70506-60)

Acifluorfen 

sodium

Danger 2 lb/gal 48 hr 0.374 0.5 50-day PHI; minor injury

Chlorimuron-ethyl 0.215 lb/lb 0.04 0.04
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 542 of 946

Table B-5 (continued). Dicamba and Alternative Registered Soybean Herbicides 

Brand

(U.S. 

EPA Reg. 

No.)

Active 

Ingredient

Signal 

Word 1

Active 

Ingredient 

Content

Reentry 

Interval 

(REI)2

Max. 

Soybean 

lb/a 

(single 

treatment)3

Max. 

Soybean 

lb/a 

(season)

Label Warnings or 

Special Directions4

Valor® SX 

(59639-99)

Flumioxazin Caution 0.51 lb/lb 12 hr 0.096 0.096 “runoff potential”; “toxic to 

aquatic invertebrates”; 

preemergence use only, no in 

crop use; do not feed forage or 

hay to livestock; crop rotation 

limit up to 18 mts. & soil type 

limits; injury under cool wet 

conditions or poorly drained 

soil; restrictions on use with 

flufenacet, alachlor, 

metolachlor, or dimenthenamid

Valor® XLT 

(59639-117)

Flumioxazin Caution 0.3 lb/lb 12 hr 0.094 0.094 “toxic to aquatic invertebrates”; 

preemergence only, no in crop 

use; do not feed forage or hay 

to livestock; crop rotation limits 

up to 30 mts; injury under cool 

wet conditions or poorly 

drained soil

Chlorimuronethyl0.103 lb/lb 0.032 0.032

Weedone®

(650, 638, 

LV4, LV6) 

and other 

2,4-D brands 

(71368-3, -6, 

-10, -11, -14, 

-19)

2,4-D; 2,4-D 

salts; 2,4-D 

esters

Varies Varies 0.93 0.93 Weedone 650 as an example: 

“toxic to aquatic invertebrates”; 

do not use on sandy soils (<1% 

O. M.); preplant to emerged 

weeds only, no in crop use; do 

not feed forage or hay to 

livestock

1 The EPA-required statement to convey to applicators the overall acute toxicity hazard posed by the product. 

Caution is more favorable than Warning, which is more favorable than Danger.

2 The period of time following application during which worker reentry into the treated area is restricted, according to 

EPA’s Worker Protection Standard (WPS).

3 The highest single-treatment and seasonal rates that can be applied to soybean according to the product Directions 

for Use label.

4 Lists specific statements extracted from the product label that represent specific hazards or limitations that may 

reduce the utility of the product for soybean weed control

5 Higher rates with directed / hooded sprayers.

6 Regional or soil type limitations may lower this rate.

7 Soybean label not yet publically available. Corn label comments are cited

PHI – preharvest interval, O. M. – organic matter, mts - months.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 543 of 946

Table B-6. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide 

Products

Active 

Ingredient

First 

Registered1

2006 

Treated 

Soybean 

Acreage

(%)2

Registration 

Review 

Status3

RED 

Date4

Max. 

Soybean lb/a 

(single 

treatment)5

Max. 

Soybean 

lb/a 

(season)

Tolerances 

(40 CFR 

180)6

Restricted 

Use7

glyphosate salts 3-May-76 97 open 2009 Sep-93 1.5 6 364 No

dicambadiglycolamine 

salt

2-Feb-56 <0.5 NA Jun-09, 

corrected 1

9 29 227 No

2,4-D acid, salts, 

and esters 3-Jun-52 10 2013 Jun-05 0.93 0.93 142 No

flumioxazin 12-Apr-2001 3 unscheduled NA 0.096 0.096 568 No

imazethapyr 30-Jan-87 3 2014 Jun-06 0.0648 0.0648 447 No

cloransulammethyl 29-Oct-1997 1 2011 NA 0.04 0.055 514 No

chlorimuronethyl 4-Apr-86 4 2011Sep-04 

TRED 0.14 0.148 429 No

fomesafen 10-Apr-87 2 open 2007

TRED 

Aug-07

0.375 0.3758 433 No

flumicloracpentyl 23-Mar-94 1 open 2009Aug-05 

TRED 0.081 0.11 477 No

sulfentrazone 22-Nov-93 1 open 2009 NA 0.31 0.31 498 No

thifensulfuron 25-Apr-86 1 2011 NA 0.013 0.013 439 No

imazaquin 20-Mar-86 1 2014

TRED 

Dec-05 

0.123 0.1238 426 No

imazamoxammonium

17-Apr-95 <0.5 2014 NA 0.04 0.04 1223 No

paraquat 

dichloride 8-Jan-80 1 2012 Aug-97 1.0 2.9 205 Yes

lactofen 1-Apr-87 <0.5 open 2007

TRED 

Sep-03 

0.3 0.4 432 No

glufosinateammonium

29-May-91 <0.5 open 2008 NA 0.66 0.8 473 No

2,4-DB 30-Jun-66 <0.5 2014 Jan-05 0.4 0.4 331 No

fluthiacet-methyl 14-Apr-99 <0.5 unknown NA 0.0065 0.009 551 No

acifluorfen 

sodium 29-May-81 <0.5 unscheduled Sep-09 0.374 0.5 383 No

Mesotrione 4-Jun-01 0.0 unscheduled NA 0.1875 0.1875 571 No

TRED denotes Tolerance Reregistration Eligibility Decision

1 The date the herbicide was first approved for any use (e.g., industrial) by U.S. EPA.

2 The percentage of the herbicide-treated soybean acres that were treated with each herbicide in AR, IA, IL, IN, KS, KY, LA, MI, MN, MS, MO, 

NE, NC, ND, OH, SD, TN, VA, and WI in 2006 (USDA-NASS, 2007b) .

3 The herbicide’s progress in the ongoing EPA program named as Registration Review. Year indicates when the official docket was or will be 

opened. EPA is required by law to re-evaluate pesticides periodically, generally every 10-15 years.

4 The date when EPA issued a Reregistration Eligibility Decision document. Reregistration was an earlier re-evaluation program designed to 

ensure that supporting data are up-to-date for a.i.s first registered before 1984. TRED means Tolerance Reassessment Eligibility Decision, 

which refers to an alternative review path that some post-1984 a.i.s followed.

5 The maximum amount of the herbicide that can be applied to soybean in a single treatment or during the entire season, according to product 

labels.

6 The number of the paragraph in the Code of Federal Regulations where that herbicide’s food and feed tolerances are listed.

7 An EPA pesticide classification that restricts a product, or its uses, to use by a certificated pesticide applicator or under the direct supervision of a 

certified applicator. See 40 CFR 152.160.

8 Regional or soil type limitations may lower this rate.

9 Maximum treatment rates for the proposed dicamba label.
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B.2.4. Herbicide-resistant Weeds in Soybean Production

The emergence and growth of herbicide-resistant weeds (including glyphosate-resistant weed 

biotypes) in certain areas of the U.S. over the past decade has required growers to adapt and 

implement improved weed management strategies. Glyphosate-resistant weed biotypes that can be 

found in soybean fields include Palmer pigweed (Amaranthus palmeri), spiny pigweed (Amaranthus 

spinosus), tall waterhemp (Amaranthus tuberculatus), common ragweed (Ambrosia artemisiifolia), giant 

ragweed (Ambrosia trifida), horseweed (Conyza canadensis), kochia (Kochia scoparia), goosegrass (Eleusine 

indica), Italian ryegrass (Lolium multifloru), and Johnsongrass (Sorghum halepe) (Heap, 2011, 2013). 

Tables B-7 and B-8 summarize known resistance among the major weed species present in certain 

soybean-growing regions of the U.S. within each of the key soybean herbicide groups and herbicide 

classes active on broadleaf weeds (Heap, 2011). In certain areas of the U.S., resistance to the ALS 

group of herbicides is present in most of the major broadleaf weed species commonly found in 

soybeans. For common ragweed and waterhemp, there is known resistance to at least one member 

for several of the major soybean herbicide chemistry classes. While there are effective options for 

managing common ragweed, waterhemp, Palmer pigweed and other key broadleaf weeds, the 

availability of additional herbicide modes-of-action will help combat future resistance in soybeans 

and manage existing herbicide-resistant weed populations in areas of the U.S. where such 

populations exist. Similarly, there has been an increase in the detection of weed populations with 

multiple resistance (i.e., resistance to multiple herbicide modes-of-action) in some weed species, for 

example, Amaranthus spp. (Tranel et al 2010). The emergence of these resistant biotypes in certain 

areas of the U.S. and continued need to utilize diversified weed management practices supports the 

need for additional herbicide modes-of-action in major crops such as soybean. 

The relative occurrence of herbicide-resistant weeds varies between the different sub-groups of 

auxinic (phenoxy in B-7 and B-8) herbicides. Considering that auxin herbicides have been widely 

used in agriculture for more than 60 years, weed resistance to this class is relatively low (29 species, 

to date, worldwide) and its development has been slow, especially when compared to the speed of 

appearance of resistance to ALS inhibitors (107 species) or triazine-resistant populations (68 species) 

(Heap 2012b). The relatively low incidence of auxinic herbicide resistance is believed to be 

attributable to the fact that there are multiple target sites for these herbicides (Gressel and Segel 

1982; Morrison and Devine 1993).

Monsanto scientists and academics recommend the use of multiple herbicide modes-of-action in the 

glyphosate-tolerant soybean system regardless of whether glyphosate-resistant or hard-to-control 

broadleaf weeds are present. Monsanto specifically recommends the use of a soil residual as part of 

the weed management system. Growers may also choose to switch to other weed management

systems in their soybean fields. APHIS has approved other herbicide-tolerant soybean including 

phosphinothricin-tolerant, ALS-tolerant, and HPPD-tolerant soybean events (Table B-9). For 

growers who choose to use the glyphosate-tolerant soybean system, Monsanto and university 

extension agents provide recommended control options for glyphosate-resistant weeds. These 

options include the use of residual and postemergent herbicides such as synthetic auxins (2,4-D), 

ACCase inhibitors (clethodim, sethoxydim), PPO inhibitors (lactofen, fomesafen), and ALS 

inhibitors (cloransulam). These herbicides alone or combinations of these herbicides as well as 

traditional tillage methods are and will continue to be used to control glyphosate-resistant or hardto-control broadleaf weeds.
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Table B-7. Known Weed Resistance in the Southern U.S.1

Most 

Common 

Broadleaf 

Weeds 

(# states 

where 

listed as a 

top weed)

Resistance 

Group 2

ALS

(Group 2)

PPO 

(Group 14)

PS II 

(Group 5)

Glycine 

(Group 9)

Phenoxy 

(Group 4)

Chemistry

Class 2

Sulfonyl 

Urea

Imidazolinones Triazoles Diphenyl 

ether

N-phenyl 

thalimide

Triazinones - Phenoxy Benzoic 

acid

Example chlorimuron imazapyr chloransulam lactofen

fomesafen

flumioxazin metribuzin glyphosate 2,4 D dicamba

Morning glory (5)

Sida (prickly sida (5) X

Sicklepod (4)

Hemp sesbania (3)

Pigweed spp. 3(3) X X X X X X X

Palmer pigweed (2) X X X X

Cocklebur (1) X X X

Horseweed (marestail) 

(1)

X X X

1 Source: www.weedscience.org

2 Cross resistance is possible within a resistance group and/or chemistry class, but cross resistance can be mitigated with diversified weed management practices.

3 Includes redroot pigweed, common waterhemp, spiny amaranth, and smooth pigweed
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Table B-8. Known Weed Resistance in the Midwest U.S. 1

Most 

Common 

Broadleaf 

Weeds 

(# states 

where 

listed as a 

top 

weed)

Resistance 

Group 2

ALS

(Group 2)

PPO 

(Group 14)

PS II 

(Group 5)

Glycine (Group 9) Phenoxy 

(Group 

4)

Chemistry 

Class 2

Sulfonyl 

Urea

Imidazolinones Triazoles Diphenyl 

ether

N-phenyl 

thalimide

Triazinones - Phenoxy Benzoic 

acid

Example chlorimuron imazapyr chloransulam lactofen

fomesafen

flumioxazin metribuzin glyphosate 2,4 D dicamba

Pigweed spp. 3 (12) X X X X X

Velvetleaf (11)

Lambsquarters (10) X X X

Cocklebur (9) X X X

Common ragweed (7) X X X X X X

Smartweed spp. (6)

Morning glory (5)

Waterhemp (5) X X X X X X

Horesweed (marestail) 

(3)

X X X

Giant ragweed (3) X X X X

Kochia (2) X X X X

1 Source: www.weedscience.org

2 Cross resistance is possible within a resistance group and/or chemistry class, but cross resistance can be mitigated with diversified weed management practices.

3 Includes redroot pigweed and smooth pigweed
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Table B-9. Deregulated Biotechnology-derived Soybean Products1

Phenotype Event Institution Date Deregulated

Herbicide-tolerant

(Glyphosate/Isoxaflutole)

FG72 Bayer

Crop Sciences

August, 2013

Omega 3 Fatty Acid MON 87769 Monsanto July, 2013

High Oleic Acid, Low 

Saturated Fat

MON 87705 Monsanto December, 2011

Lepidopteran Resistant MON 87701 Monsanto June, 2011 

High Oleic Acid DP-3Ø5423-1 Pioneer June, 2010

Glyphosate- and ALStolerantDP-356043-5 Pioneer July, 2008

Glyphosate-tolerant MON 89788 Monsanto February, 2007

Phosphinothricin-tolerant GU262 AgrEvo October, 1998

Phosphinothricin-tolerant A5547-127 AgrEvo May, 1998

Altered Oil Profile G94-1, G94-19, G-168 DuPont May, 1997

Phosphinothricin-tolerant W62, W98, A2704-12, 

A2704-21, A5547-35

AgrEvo August, 1996

Glyphosate-tolerant 40-3-2 Monsanto May, 1994

1 USDA-APHIS 2013

B.2.4.1. Sustainable Use of Dicamba as a Weed Management Option in Soybean

Dicamba is a broadleaf herbicide that does not provide control of grass weeds. For that reason, DT 

soybean will be sold only in soybean varieties that also contain other herbicide-tolerant traits, such as 

with the glyphosate-tolerant soybean system (e.g., MON 89788). Soybean varieties containing both 

DT soybean and MON 89788 will enable dicamba to be applied with glyphosate or other soybean 

herbicides in an diversified weed management program, ideally as a mixture, to control a broad 

spectrum of grass and broadleaf weed species. Dicamba applications on DT soybean will provide 

effective control of glyphosate-resistant broadleaf weeds and improve the control of annual and 

perennial broadleaf weed species, some of which are difficult to control with glyphosate. Dicamba 

will also help mitigate the potential for development of and/or combat existing weed resistance 

issues that can limit the use of the PPO- and ALS-inhibiting herbicide groups by providing an 

additional mode-of-action for management of certain broadleaf species that are known to be prone 

to resistance to many of the current options for weed management (i.e. Amaranthus spp.). DT 

soybean will foster the adoption of Integrated Pest Management (IPM) practices in soybeans by 

allowing growers to continue to focus primarily on postemergence in-crop weed control, as they 

have practiced with the glyphosate-tolerant soybean system. This will allow growers to delay some 

herbicide treatments until field scouting indicates a need for additional postemergence weed control, 

which is consistent with the principles of IPM. Increasing postemergence herbicide options in 

soybeans is important, especially in conservation tillage situations, where consistency of 
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postemergence herbicides has generally been greater than that of soil active residual products and 

thus a driving factor in the adoption of conservation tillage systems in the U.S. 

Upon the inclusion and integration of DT soybean into the glyphosate-tolerant soybean system and 

approval of the use of dicamba on DT soybean104, preplant/preemergence applications of dicamba 

can be made up to 1.0 lb a.e./A up through crop emergence (cracking) followed by two in-crop 

postemergence applications up to 0.5 lb a.e./A through the R1/R2 growth stage in soybean. 

However, the majority of weed control scenarios in DT soybean will not require the use of the 

proposed maximum labeled rate, and the anticipated commercial pre-plant/preemergence and incrop use rates are between 0.25 to 0.38 lb a.e./A (based on established weed control rates for 

soybean weeds), with an average application rate of 0.38 lb a.e./A as described in Section VIII.H of 

the DT soybean Petition for Deregulation). Residual herbicides also will be recommended for use, 

in addition to glyphosate and dicamba, to provide early season weed control and to supplement 

dicamba activity on certain hard-to-control and glyphosate-resistant weed biotypes, such as 

glyphosate-resistant Palmer Amaranth, where weed populations can be very substantial. 

Dicamba, as a complementary herbicide to glyphosate, will provide new weed control options in 

soybean that strengthen the utility and sustainability of glyphosate as a weed control tool in the 

glyphosate-tolerant soybean system. Likewise, glyphosate, as a complementary herbicide to 

dicamba, would strengthen the utility and sustainability of dicamba as a weed control tool for DT 

soybean to be integrated into the glyphosate-tolerant soybean system. 

In the event that there is known or suspected presence of a dicamba-resistant weed, it will be 

possible to provide the affected grower(s) with options for managing the dicamba-resistant biotype. 

There are multiple preemergence (including soil residuals) and postemergent herbicide options for 

managing broadleaf weed populations that are resistant or may potentially develop resistance to 

dicamba in soybean, as well as for crops grown in rotation with soybean. These options are noted in 

Table B-10. 

 

104 Monsanto has submitted to EPA an application to amend Registration Number 524-582 to register a new use pattern 

for dicamba on DT soybean. 
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Table B-10. Management Recommendations for Control of Dicamba- and Other Synthetic Auxin-Resistant Weeds

Weed Species Primary Crop Soybean

Rotational Crops / Other Uses

Corn Wheat Pastures/Roadsides Rice

Kochia Saflufenacila Atrazinea Saflufenacila

(Kochia scoparia) Clomazonea Saflufenacila Glyphosatea

Flumioxazina Isoxaflutolea Bromoxynil/MCPAa

Glyphosatea Mesotrionea

Paraquata Glyphosatea

Prickly Lettuce Saflufenacila Saflufenacila Saflufenacila

(Lactuca serriola) Chlorimuron/metribuzina Atrazinea Triasulfurona

Glyphosate + imazethapyra Carfentrazone + 

atrazinea

Metsulfuron + 

thifensulfurona

Isoxaflutole + 

atrazinea

Wild Carrot Glyphosatec Glyphosatec

(Daucus carota) Chlorimuronc Atrazinec

Chlorimuron/metribuzinc Primisulfuronc

Nicosulfurond

Halosulfurond

Field Bindweed Glyphosatea Glyphosatea Glyphosatea

(Convolvulus 

arvensis)

Glyphosate + 

imazethapyra

Glyphosate + 

Imazamoxa
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Table B-10 (continued). Management Recommendations for Control of Dicamba- and Other Synthetic Auxin- Resistant Weeds

Weed Primary Crop Soybean

Rotational Crops / Other Uses

Corn Wheat Pastures/Roadsides Rice

Yellow Starthistle

(Centaurea 

solstitialis)

Chlorsulfuron

Aminopyralide

Spreading 

Dayflower

(Commelina 

diffusa)

Bentazon 

halosulfuron 

penoxsulam 

bispyribacf

Lambsquarters Metribuzinb Isoxaflutolea Bromoxynila

(Chenopodium Cloransulamb Atrazinea Chlorsulfuron/Metsulfurona

album)

g Saflufenacila Saflufenacila Glyphosatea

Imazamoxb Mesotrionea Saflufenacila

Glyphosateb Bromoxynilb

Waterhemp

(Amaranthus 

tuberculatus)

h

Saflufenacili

Flumioxazini

Sulfentrazonei

Fomesafeni

Metolachlori

Metolachlori

Atrazinei

Saflufenacili

Mesotrionei

Carfentrazonei

Mesulfuronj

Triasulfuronj

Prosulfuronj

Fluroxypry/bromoxynilj

aBernards et al., 2010.

bLoux et al., 2010.

cMichigan State University Extension, 2010.

dKells and Stachler, 1997. 

ePNWE, 2010.

fUniversity of Arkansas CES, 2010. 

gResistance to lambsquarters has only been confirmed in New Zealand.

hBernards et al., 2012

iLoux et al., 2013

jUniversity of Nebraska, 2013
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B.2.4.2. Stewardship of Dicamba Use on DT soybean 

In order to steward the use of agricultural herbicides and herbicide-tolerant cropping systems such 

as DT soybean integrated into the glyphosate-tolerant soybean, Monsanto has conducted 

investigations and worked extensively with academics and other herbicide manufacturers to 

understand and recommend best practices to manage herbicide resistance. These investigations 

have demonstrated that one of the major factors contributing to the development of resistant weed 

biotypes in certain areas of the U.S. has been inadequate weed control management practices. The 

lack of adequate management includes: 1) application of herbicides at rates below those indicated on 

the product label for the weed species, and 2) sole reliance on a particular herbicide for weed control 

without the use of other herbicides or cultural control methods (Beckie, 2006; Peterson et al., 2007). 

B.2.4.3. Weed Control Recommendations

The proposed label for dicamba use on DT soybean – which is currently pending before EPA - is 

based on the maximum allowable use rates and patterns. Prior to launch of DT soybean in the 

glyphosate-tolerant soybean system, Monsanto, in cooperation with academics, will conduct trials to 

confirm the optimum rate and timing for dicamba alone and in combination with glyphosate and 

other herbicides for particular weed species. Recommendations to growers will be developed from 

this information and will be provided in herbicide product labels, Monsanto’s Technology Use 

Guide (TUG), and in other education and training materials to be broadly distributed. Specifically, 

current research conducted by Monsanto to define the optimum weed management systems indicate 

the following: 1) in the absence of glyphosate-resistant populations, the recommendation will be to 

apply a soil active residual herbicide followed by a postemergence application of glyphosate plus 

dicamba to control weed escapes, and 2) in the presence of glyphosate-resistant populations, the 

same system will be recommended with a potential second application of glyphosate plus dicamba if 

needed. In this latter case, the preemergence herbicide to be recommended will be one with activity 

against the targeted glyphosate-resistant species. This will ensure more than one mechanism of 

action against the targeted species, which is a fundamental component of a good weed resistance 

management program. These management systems will reduce the potential for further resistance 

development to glyphosate, or to dicamba or other critical soybean herbicides. In conservation 

tillage systems, a preplant application of glyphosate plus dicamba may be recommended in some 

situations in addition to the in-crop applications described above. This is not expected to increase 

selection pressure on either product since the preplant weed spectrum is generally different from the 

in-crop spectrum. 

B.2.4.4. Dispersal of Technical and Stewardship Information

To support the introduction of varieties containing DT soybean, Monsanto will use multiple 

methods to distribute technical and stewardship information to growers, academics and grower 

advisors regarding the use of the product as part of a diversified weed management system. 

Growers who purchase Monsanto varieties containing DT soybean sign a limited use license known 

as the Monsanto Technology Stewardship Agreement (MTSA). The MTSA obligates growers to 

comply with certain requirements, including the Monsanto Technology Use Guide (TUG). The 

TUG will set forth the requirements and best practices for the cultivation of DT soybean including 

recommendations on weed resistance management practices.
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The weed resistance management practices that will be articulated in the TUG will also be broadly 

communicated to growers and retailers in order to minimize the potential for the development of 

resistant weeds. These practices will be communicated through a variety of means, including direct 

mailings to each grower purchasing a soybean variety containing DT soybean, a public website105, 

and reports in farm media publications. The overall weed resistance management program will be 

reinforced through collaborations with U.S. academics who will provide their recommendations for 

appropriate stewardship of dicamba in soybean production, as well as by collaboration with crop 

commodity groups who have launched web-based weed resistance educational modules. Finally, 

Monsanto will urge growers to report any incidence of repeated non-performance of dicamba on 

weeds in fields planted with DT soybean, and Monsanto will investigate cases of unsatisfactory weed 

control to determine the cause as discussed below in Section B.2.4.6. 

The EPA is the U.S. federal regulatory agency that administers the federal law governing pesticide 

sale and use under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). EPA regulates 

under FIFRA the pesticides (including herbicides) that are used with crops, including GE herbicidetolerant crops like DT soybean and DGT cotton. FIFRA requires all pesticides to be registered 

before distribution or sale, unless they are exempted. Under FIFRA, EPA must approve each 

distinct pesticide product, each distinct use pattern, and each distinct use site. Each crop for 

example, consititues a unique use site and no registered pesticide may be applied to any crop unless 

EPA has approved that specific pesticide/crop use. 

In addition each pesticide must be labeled with enforceable directions for use on a crop by crop 

basis. It is a violation of FIFRA to use any registered pesticide in a manner inconsistent with its 

labeling, subject to criminal and civil penalty. 1 For that reason, an approved herbicide cannot be 

lawfully used on a corresponding herbicide-tolerant crop, unless EPA approves a label amendment 

for such use.

EPA encourages pesticide manufacturers to provide growers with information regarding an 

herbicide’s mode-of-action to aid growers in planning herbicide use practices and to foster the 

adoption of effective weed resistance management practices as specified by EPA in Pesticide 

Registration (PR) Notice 2001-5 (U.S. EPA, 2001). In that document EPA states that “this 

approach to resistance management is sound and would be highly beneficial to pesticide 

manufacturers and pesticide users.” EPA approves all pesticide label use instructions based on its 

evaluation of supporting data supplied by the pesticide registrant or manufacturer. By approving a 

label, EPA has concluded that the product will not cause unreasonable adverse effects to the 

environment when used in accordance with the label’s directions. After EPA approves a pesticide 

label, it is a violation of federal law to use the pesticide for a use or in a manner not in accordance 

with the label directions. Monsanto incorporates EPA’s guidelines for pesticide resistance 

management labeling on its agricultural herbicide labels, and will continue to do so in the future. 

Monsanto will adopt a similar approach to pesticide resistance management guidance on its dicamba 

product labels.

 

105 http://www.monsanto.com/weedmanagement/Pages/default.aspx
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In summary, Monsanto will require weed resistance management practices through the MTSA and 

TUG for its biotechnology-derived herbicide-tolerant products, such as DT soybean integrated into 

the glyphosate-tolerant soybean system, and to promote these practices through product labeling 

and educational outreach efforts as an effective means to manage weed resistance development for 

both dicamba and glyphosate. 

B.2.4.5. Weed Resistance Management Practices

Monsanto will provide information to growers and grower advisors on best management practices 

to mitigate the potential for development of resistance to dicamba. The weed resistance 

management recommendations for the use of dicamba in conjunction with soybean varieties 

containing DT soybean will be consistent with the Herbicide Resistance Action Committee’s 

guidelines for prevention and management of herbicide resistance (HRAC, 2010)106. These 

guidelines recommend a diversified approach to weed resistance management including crop 

management (i.e., row spacing, etc), cultivation techniques, and the use of multiple herbicide modesof-action to manage a weed population. 

In cases where resistance is confirmed for dicamba in soybean producing areas, Monsanto and 

university/Cooperative Extension Service (CES) personnel will provide recommendations for 

alternative herbicide control methods to growers. These recommendations would be made available 

through Monsanto supplemental labels, Monsanto and university publications, and internet sites to 

growers, consultants, retailers and distributors. For all existing cases of dicamba-resistant weeds in 

the U.S. and globally today, alternative herbicides and cultural methods are available to growers to 

effectively control these biotypes. Examples of recommended alternative herbicides from 

university/CES personnel that are applicable to weed species known to be resistant to dicamba and 

other synthetic auxin herbicides are found in Table B-10. It is important to note that there are many 

alternative options in each situation.

B.2.4.6. Monsanto Weed Performance Evaluation and Weed Resistance Management Plan

An important part of a weed resistance management plan is the timely acquisition of information 

regarding product performance. Monsanto has an extensive technical, sales and marketing presence 

in the soybean markets where DT soybean will be grown. Through our relationships with farm 

advisors, key university/CES personnel, and growers using our seeds and traits products, Monsanto 

will acquire important and timely information regarding product performance. This will allow the 

timely recognition of performance issues that could arise related to weed resistance or other means. 

Field employees and hired consultants are trained and provided processes for responding to product 

performance inquiries. Individual performance issues that could be related to potential resistance 

are promptly handled. In addition, performance inquiries are periodically reviewed by Monsanto for 

trends that could indicate the need for follow up action on a broad scale. 

 

106 The Herbicide Resistance Action Committee (HRAC) is an international body founded by the agrochemical industry 

for the purpose of supporting a cooperative approach to the management of herbicide resistance and the 

establishment of a worldwide herbicide resistance database. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 554 of 946

If resistance is confirmed, the scientific and grower communities will be notified and a weed 

resistance mitigation plan will be implemented by Monsanto in cooperation with the 

university/CES. The mitigation plan will be designed to manage the resistant biotype through 

effective and economical weed management recommendations implemented by the grower. The 

scope and level of intensity of the mitigation plan may vary depending on a combination of the 

following factors: 1) biology and field characteristics of the weed (seed shed, seed dormancy, etc.), 2) 

importance of the weed in the agricultural system, 3) resistance status of the weed to other 

herbicides with alternate modes-of-action, and 4) availability of alternative control options. These 

factors are analyzed by Monsanto and university/CES personnel in combination with economic and 

practical management considerations to develop a tailored mitigation strategy. The plan considers 

what is technically appropriate for the particular weed and incorporates practical management 

strategies that can be implemented by the grower. 

After a mitigation plan is developed, Monsanto communicates the plan to the grower community 

through the use of supplemental labeling (labeling which includes newly approved use directions, or 

other instructions), informational fact sheets, retailer training programs, agriculture media and/or 

other means, as appropriate.

In addition to the grower inquiry initiated process, Monsanto, alone and/or in cooperation with 

university/CES, will conduct field studies to understand the potential for weed resistance and weed 

shifts as the result of various weed management programs implemented for DT soybean integrated 

into the glyphosate-tolerant soybean system. These studies will allow researchers to better track 

specific factors that can influence the development of resistance to specific weeds. 

B.2.5. Benefits of DT Soybean Production 

B.2.5.1. Overview

As discussed previously, Dicamba-tolerant soybean will provide an additional weed management 

tool for effective and sustainable weed management in soybean production. Dicamba-tolerant 

soybean will be combined with glyphosate-tolerant soybean, e.g., Roundup Ready 2 Yield

(MON 89788), utilizing traditional breeding techniques to produce a stacked trait product of 

dicamba-glyphosate-tolerant soybean. This combination of herbicide-tolerance traits will allow 

growers to use dicamba and glyphosate herbicides in a diversified weed management program to 

control a broad spectrum of grass and broadleaf weed species in soybean. Dicamba-tolerant 

soybean will contribute additional benefits and value to the well-established and effective 

glyphosate-tolerant weed control system. Glyphosate provides excellent control of many annual and 

perennial grass and broadleaf weed species, whereas dicamba provides effective control of many 

annual and perennial broadleaf weed species. 

Dicamba-tolerant soybean will enable early preplant applications, preemergence applications up to 

the day of crop emergence (cracking), and postemergence in-crop applications through the R1 

growth stage of soybean. Dicamba will be complementary to glyphosate for weed management in 

soybeans due to the efficacy of dicamba on glyphosate-resistant broadleaf weeds and other hard-tocontrol broadleaf weed species and the application flexibility facilitated with dicamba-tolerant 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 555 of 946

soybean, and it will help to preserve the glyphosate-tolerant weed control system and other modeof-action herbicides in the major row crop production practices in soybean, corn and cotton. 

Beginning in 2007, numerous field experiments have been conducted by university weed control 

specialists and Monsanto researchers in the major soybean production regions of the U.S. to 

evaluate the control of glyphosate-resistant and hard-to-control weeds using various rates and timing 

of dicamba and glyphosate plus dicamba tank mixtures in dicamba-glyphosate-tolerant soybean. 

These experiments provide valuable data for determining the best recommendations and weed 

management systems for optimum control of problematic weed species in various climate 

conditions and soybean production systems across the U.S. Although additional studies are on 

going to further refine these product and system recommendations, Table B-11 provides a concise 

summary of the general weed management system recommendations proposed for dicambaglyphosate-tolerant soybean for both conventional and conservation tillage practices. 

These weed management system recommendations represent a high-end proposal for dicamba use 

associated with dicamba-glyphosate-tolerant soybean. The actual number of applications and timing 

of applications of dicamba or glyphosate that the grower will make will vary depending on the 

specific weed spectrum, weed infestation levels, and the agronomic situation of the individual 

soybean field. Applying a residual herbicide preemergence in sequence with glyphosate plus 

dicamba postemergence, or tank mixing a residual herbicide with glyphosate plus dicamba 

postemergence could be considered as an alternative to two postemergence applications of 

glyphosate plus dicamba for season-long weed control.

These proposed recommendations recognize the differences in growth habits and competitiveness 

of certain glyphosate-resistant weed species. Option 1 would be recommended for more aggressive 

glyphosate-resistant weed species, such as Palmer amaranth (Amaranthus palmeri) and waterhemp 

(Amaranthus tuberculatus). These weed species are very fast growing, highly competitive with crops, 

high seed producers, very densely populated, and germinate and emerge throughout the growing 

season (Nordby et al., 2007; Sprague, 2012; Keely et al., 1987; Fast et al., 2009). Two sequential 

postemergence applications will generally be required to control late-season emergence of these 

weed species. However, low rainfall conditions and/or early crop canopy closure that can be 

associated with narrow row spacing of soybean can reduce late-season weed emergence and 

potentially reduce the number of dicamba postemergence applications. Option 2 would be used for 

less aggressive glyphosate-resistant weed species, such as horseweed (Conyza canadensis), common 

ragweed (Ambrosia artemisiifolia) and giant ragweed (Ambrosia trifida).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 556 of 946

Table B-11. Anticipated Weed Management Recommendations for DT Soybean Combined 

with Glyphosate-Tolerant Soybean1

Application 

Timing

Conventional Tillage2 Conservation Tillage 2

(No-till or reduced till)

No GR 

Weeds

GR Weeds or Suspected 

GR Weeds No GR 

Weeds

GR Weeds or Suspected 

GR Weeds

Option 13 Option 24 Option 13 Option 24

Preemergence 

(burndown, at 

planting) 5

Residual Residual Residual

Residual

+

Glyphosate

+

Dicamba

Residual

+

Glyphosate

+

Dicamba

Residual

+

Glyphosate

+

Dicamba

Postemergence 1 

(V1-V3)

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Glyphosate

+

Dicamba

Postemergence 2 

(V4-R2) ---

Glyphosate

+

Dicamba

--- ---

Glyphosate

+

Dicamba

---

1 The anticipated use patterns represent a high-end estimate for predicating dicamba use associated with DT soybean 

integrated with the glyphosate-tolerant soybean system. Actual weed control practices by growers will vary depending 

on the specific weed spectrum and agronomic situation of the individual soybean field, specifically dicamba use could 

be lower especially for the preemergence and second postemergence applications.

2 Average rate for dicamba is 0.38 pound a.e. per acre except for fields with glyphosate resistant (GR) species where a 

0.5 pound a.e. per acre postemergence application rate will be recommended. In some situations, the second 

postemergence application may not be needed.

3 Option 1 would be used for more aggressive glyphosate resistant weed species, such as Ambrosia or Amaranthus

species.

4 Option 2 would be used for less aggressive glyphosate resistant weed species, such as marestail.

5 Monsanto and academics recommend the use of soil residuals as part of a comprehensive weed resistance 

management program to ensure that two effective herbicide modes-of-action are used in soybean and to provide 

protections against additional resistance development to existing soybean herbicides.

Monsanto and university weed control specialists continue to recommend and encourage 

preemergence applications of soil residuals as part of a comprehensive weed resistance management 

program to ensure the use of two or more effective herbicide modes-of-action for weed control and 

to minimize the risk of additional weed species developing resistance to existing soybean herbicides. 

Preemergence soil residuals also provide early season weed control to reduce early weed competition 

to protect yield potential and provide greater flexibility in timing of postemergence applications. In 

addition, preemergence residuals will assist in the control of grasses and certain hard-to-control 

broadleaf weed species. The addition of residual preemergence herbicides with glyphosate and 

dicamba will be an effective program for optimum weed control and long-term sustainability of the 

dicamba-tolerant technology. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 557 of 946

B.2.5.2. Benefits of the Weed Management System of Dicamba-Glyphosate-Tolerant 

Soybean

Extensive research by both university weed control specialists and Monsanto researchers from 2007 

through 2011 demonstrates that growers will realize several benefits from utilizing the proposed 

weed management systems of dicamba-glyphosate-tolerant soybean. These benefits include: 

 Effective and sustainable management of glyphosate-resistant weed species;

 Improved and more consistent control of hard-to-control broadleaf weed species; 

 Excellent crop safety to dicamba and glyphosate herbicides to maximize soybean yield 

potential;

 Application flexibility in the event of challenging weather conditions especially in the spring;

 Proactive program for weed resistance management; and 

 Preservation of conservation tillage benefits. 

Each benefit attribute is described and discussed below to substantiate the benefit in greater detail.

B.2.5.2.1. Effective and Sustainable Management of Glyphosate-Resistant Weed Species

Glyphosate has been used extensively in agricultural production systems since being commercially 

introduced in 1974. Roundup Ready soybean was commercially introduced in 1996, further 

expanding the use of glyphosate in soybean. Currently, glyphosate-tolerant soybean represent 93% 

of all soybean acres planted in the U.S. (USDA-NASS, 2012), up from 89% in 2006 (USDA-NASS, 

2007). Due to the broad-spectrum activity of glyphosate, it has been possible for growers to rely 

predominately on glyphosate for weed management and not utilize diversified weed management 

practices such as crop rotation, mechanical cultivation or use of multiple herbicide modes-of-action. 

Reliance on glyphosate-only herbicide programs in glyphosate-tolerant crops for total weed 

management in the absence of other herbicides and weed control practices has contributed to the 

evolution of weed species that are resistant to glyphosate in certain areas of the U.S. Currently, 

there are 13 weed species (6 grasses and 7 broadleaf species) that are resistant to glyphosate in the 

U.S (Heap, 2012). Populations of the following six broadleaf weed species are resistant to 

glyphosate and are agronomically important weeds in soybean: Palmer amaranth (Amaranthus 

palmeri), common waterhemp (Amaranthus tuberculatus), giant ragweed (Ambrosia trifida), horseweed 

(Conyza Canadensis), common ragweed (Ambrosia artemisiifolia), and kochia (Kochia scoparia) (Johnson et 

al., 2010). University weed control specialists and Monsanto researchers have extensively evaluated 

the effectiveness of dicamba and glyphosate to control several of these glyphosate-resistant weeds. 

Many of the early studies (2007-2009) were focused on determining the efficacy of dicamba and 

dicamba plus glyphosate applied preplant, preemergence, and postemergence in soybean compared 

to glyphosate applied alone. Later studies (2010-2011) were focused on evaluating the efficacy of 

various weed management systems utilizing dicamba and glyphosate with and without residual 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 558 of 946

herbicides for control of glyphosate-resistant weed species. In these studies glyphosate was applied 

at labeled rates of 0.75 to 1.0 lbs. a.e./acre.

B.2.5.2.1.1. Glyphosate-Resistant Palmer Amaranth

Palmer amaranth is a summer annual broadleaf that is a problematic weed in the mid-south and 

southeastern U.S. (Sprague, 2012). It is considered to be one of the most competitive and aggressive 

of the pigweed species because of its rapid growth and prolific seed production. Palmer amaranth is 

also dioecious (the male and female flowers occur on separate plants, which leads to greater genetic 

diversity in the plant population and increases the potential for spreading herbicide resistance). 

Studies conducted on glyphosate-resistant Palmer amaranth support the importance of making 

dicamba applications early in the season to small weeds (4 inches or less in height) and applying 

dicamba at a minimum rate of 0.5 lbs. a.e./acre for effective control. Although dicamba rates of 0.25 

lbs. a.e./acre were effective in the early studies, later studies showed more consistent control with a 

dicamba rate of 0.5 lbs. a.e./acre. Diversified weed management programs consisting of a residual 

preemergence herbicide followed by one or two sequential postemergence applications of glyphosate 

plus dicamba or a total post program consisting of two sequential postemergence applications of 

glyphosate plus dicamba provide excellent control of glyphosate-resistant Palmer amaranth. 

 Field efficacy studies conducted by university researchers in Georgia and North Carolina 

from 2007 to 2009 indicate that the inclusion of dicamba in the postemergence treatment 

with glyphosate significantly improved the control of natural populations of glyphosateresistant Palmer amaranth versus glyphosate alone (Johnson et al., 2010). Palmer amaranth 

control increased from 60 to 100% with the addition of dicamba (0.25 lbs. a.e./acre) to 

glyphosate as a postemergence treatment. 

 Results from field studies conducted in 2011 across seven locations in the southeast and 

mid-south states on mixed populations of glyphosate-resistant and glyphosate-susceptible 

palmer amaranth emphasize the importance of early application timing for effective control 

of this weed (Eubank et al., 2012). When applied to 3-inch plants, two sequential in-crop 

postemergence applications of dicamba (0.5 lbs a.e./acre) and glyphosate plus dicamba (0.5 

lbs. a.e./acre) provided 90 to 92% control. When applied to 9-inch plants, the control 

following the two sequential applications of dicamba plus glyphosate dropped to 81-85%. 

 Studies conducted in the mid-south also demonstrate the importance of rate plus timing of 

dicamba applications on the control of glyphosate-resistant Palmer amaranth (Edwards et al., 

2012). Dicamba at 0.25 lbs. a.e./acre tank mixed with glyphosate and applied on 2-, 4-, and 

6-inch plants provided 94, 74, and 62% control at 28 days after treatment, respectively. 

Increasing the rate of dicamba to 0.5 lbs. a.e./acre in the tank mixture resulted in 97, 86, and 

77% control. This study indicates that 0.5 lbs. a.e./acre of dicamba is required in tank 

mixture with glyphosate to achieve satisfactory control of Palmer amaranth plants up to 4 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 559 of 946

inches in height and will be a key component of Monsanto’s weed management 

recommendations for dicamba. Greenhouse studies conducted on various populations of 

Palmer amaranth indicate there is a 2.2 fold difference in dicamba dose required to provide 

80% control between most and least susceptible Palmer amaranth plants which further 

supports the need for the 0.5 lbs. a.e./acre rate to provide consistent control (Crespo et al., 

2011; Crespo et al., 2012). Furthermore, since control with dicamba was only 86% with a 

single application of glyphosate plus dicamba (0.5 lbs. a.e./acre) at 28 days after treatment, 

these results suggest that two sequential applications of glyphosate plus dicamba will likely 

be required for effective full season control. 

 Results from studies conducted in North Carolina in 2010 show the value and effectiveness 

of the diversified weed management approach to control a mixed population of glyphosatesusceptible and -resistant Palmer amaranth (York et al., 2012). Two in-crop postemergence 

applications of glyphosate alone to 3- to 4-inch Palmer amaranth provided 61% control 26 

days after treatment. This result demonstrates that glyphosate still provides control in 

natural field mixed populations, in addition to providing control of other weed species 

present in the soybean field. Postemergence applications of glyphosate plus dicamba (0.5 

lbs. a.e./acre) followed by glyphosate alone provided 90% control. When flumioxazin was 

applied preemergence to these postemergence applications, control increased to 96%. 

Results reported by these same researchers in 2011 showed that a weed control system of 

flumioxazin preemergence followed by two sequential postemergence applications of 

glyphosate plus dicamba (0.5 lbs. a.e./acre) provided 99-100% control of Palmer amaranth at 

70 days after treatment (York et al., 2012). Palmer amaranth control was similar when 

dicamba (0.5 lbs. a.e./acre) replaced flumioxazin as the preemergence application in this 

same system. The addition of acetochlor to the initial postemergence application in either 

system slightly improved the early season control (12-15%). These data indicate the 

importance of a preemergence residual herbicide for controlling weed species such as Palmer 

amaranth that can germinate over an extended period of time.

 Field studies conducted in the mid-south (AR, MO, MS, TN) in 2011 showed that a weed 

control system of flumioxazin preemergence followed by dicamba (0.5 lbs. a.e./acre) plus 

glyphosate applied to 4-inch plants provided 97% control of Palmer amaranth (Steckel et al., 

2012). 

B.2.5.2.1.2. Glyphosate-Resistant Waterhemp

Waterhemp is a summer annual broadleaf that is common in the Midwest, but is also found in other 

areas as well (Nordby et al., 2007). Like Palmer amaranth, waterhemp is dioecious and produces 

significant amounts of seed which can germinate and compete with the crop throughout the 

growing season. Studies conducted on glyphosate-resistant waterhemp show that optimum control is 

achieved when dicamba is applied to small weeds (3-4 inches or less in height) at a rate of 0.5 lbs. 

a.e./acre. Weed management systems consisting of a preemergence residual herbicide followed by 

one or two sequential postemergence applications of glyphosate plus dicamba or a total post 

program consisting of two sequential postemergence applications of glyphosate plus dicamba 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 560 of 946

provide excellent control of glyphosate-resistant waterhemp. These conclusions are consistent with 

the conclusions for Palmer amaranth.

 Results from a field experiment conducted by the University of Missouri on natural 

populations of glyphosate-resistant waterhemp indicate that application rate, weed height, 

and the addition of glyphosate significantly impact the level of glyphosate-resistant 

waterhemp control achieved with dicamba (Spaunhorst et al., 2011). The highest level of 

control (~70%) at 21 days after treatment was achieved with glyphosate plus dicamba when 

applied to 3-inch plants at the highest dicamba rate of 0.5 lbs. a.e./acre. Control was reduced 

significantly when dicamba at the same rate was applied to taller plants 6-inch (~30%) and 

12-inch (~20%). A postemergence application of a glyphosate plus dicamba tank mixture 

provided higher levels of control than either glyphosate or dicamba alone. Similar results 

were reported on another application timing study (Spaunhorst et al., 2012). When applied 

to 3-inch plants, two sequential postemergence applications of glyphosate plus dicamba (0.5 

followed by 0.5 lbs. a.e./acre) provided 86 to 92% control of glyphosate-resistant 

waterhemp, while control dropped to approximately 40% when applied to 9-inch plants. 

Populations of glyphosate-resistant waterhemp do vary in their response to dicamba, 

indicating that the minimum rate of dicamba should be 0.5 lbs. a.e./acre to provide more 

consistent control (Crespo et al., 2012). 

 Field efficacy studies conducted by university researchers in Missouri and Illinois from 2007 

to 2009 indicate that the addition of dicamba to in-crop postemergence applications of 

glyphosate significantly improved the control of glyphosate-resistant waterhemp versus 

glyphosate applied alone (Johnson et al., 2010). Waterhemp control increased from 30 to 

95% with the inclusion of dicamba (0.25 lbs a.e./acre) with glyphosate as a postemergence 

application. In addition to improving the control of glyphosate-resistant waterhemp, adding 

dicamba to glyphosate also improved the control of waterhemp populations that were 

susceptible to glyphosate.

 A preemergence-postemergence weed control system consisting of flumioxazin plus 

chlorimuron preemergence followed by glyphosate plus dicamba (0.5 lbs a.e./acre) 

postemergence provided 99% late-season control of glyphosate-resistant waterhemp in a 

study conducted by the University of Missouri in 2011 (Bradley et al., 2012). A total post 

program including two sequential applications of glyphosate plus dicamba (0.5 lbs. a.e./acre) 

also provided 99% late-season control. Control was the same (99%) whether the initial post 

application was to 4-inch or 7.5-inch waterhemp. Two sequential postemergence 

applications of glyphosate alone provided 72% control. 

B.2.5.2.1.3. Glyphosate-Resistant Horseweed

Horseweed (also referred to as marestail) is a broadleaf weed that can follow a winter or summer 

annual life cycle and can germinate in the fall or spring, but plants can also germinate in midsummer 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 561 of 946

(Loux et al., 2006). It is predominantly a problem in no-till systems, as tillage helps to control this 

weed. Dicamba is currently recommended and rated very effective as an early preplant burndown 

application with glyphosate for control of glyphosate-resistant horseweed in soybean (MSU, 2012; 

Steckel et al., 2012). However, a minimum of one inch of rainfall/irrigation and up to a 28-day 

waiting period (dependent on the rate of dicamba) after rainfall/irrigation is required before planting

soybean to avoid crop injury (Steckel et al., 2012). Dicamba-glyphosate-tolerant soybean enables 

early preplant, preemergence, and in-crop postemergence applications of dicamba and the dicambaglyphosate weed management system can provide effective full season control of glyphosateresistant horseweed. A very effective system consists of a preplant burndown application of 

glyphosate plus dicamba (0.5 lbs. a.e./acre) plus residual herbicide followed by an in-crop 

postemergence application of glyphosate plus dicamba (0.5 lbs. a.e./acre). Preplant burndown plus 

in-crop postemergence applications of glyphosate plus dicamba also provided excellent control of 

glyphosate-resistant horseweed. However, researchers recommend the addition of a preemergence 

residual in the preplant burndown application to reduce the selection pressure for dicamba-resistant 

plants in the population (Stebbing et al., 2011).

 Field efficacy studies conducted by university researchers in Illinois, Nebraska and 

Tennessee in 2008 and 2009 indicate that inclusion of dicamba in the postemergence 

treatment with glyphosate significantly improved control of glyphosate-resistant horseweed 

versus glyphosate alone (Johnson et al., 2010). Horseweed control increased from 85 to 

98% with the addition of dicamba. Horseweed control was higher and less variable in 

treatments including a preemergence treatment of dicamba, flumioxazin, sulfentrazone, 

chlorimuron or cloransulam compared to treatments which included only postemergence 

glyphosate or glyphosate plus dicamba.

 Studies conducted in Tennessee over two years showed that glyphosate plus dicamba (0.5 

lbs. a.e./acre) applied preplant followed by the same treatment postemergence on 6-inch 

weeds provided the highest control of horseweed (>96%) in no-till soybean (Steckel and 

Montgomery, 2008). Excluding dicamba from the preplant application resulted in 

consistently poor horseweed control (60-80%). A preplant application of glyphosate alone 

provided 50% control. 

 Field studies conducted in 2010 at the University of Nebraska in no-till soybean indicate that 

glyphosate-resistant horseweed control exceeded 96% when both the preplant burndown 

application and in-crop postemergence application included dicamba (Stebbing et al., 2011). 

Follow up studies in 2011 showed that weed control systems that included a preemergence 

residual herbicide plus glyphosate plus dicamba followed by glyphosate plus dicamba 

postemergence provided 99% control of glyphosate-resistant horseweed (Stebbing et al., 

2011). Glyphosate-resistant horseweed control was unacceptable with preplant burndown 

plus postemergence applications of glyphosate alone (< 30%). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 562 of 946

 Researchers at Kansas State University achieved complete control (100%) of glyphosateresistant horseweed in no-till soybean in 2011 utilizing a weed control system including a 

preplant burndown application of glyphosate plus dicamba (0.5 lbs. a.e./acre) plus 

flumioxazin/chlorimuron (sold as a package mixture) followed by a postemergence 

application of glyphosate plus dicamba (0.5 lbs. a.e./acre) (Peterson et al., 2011). When 

sulfentrazone/chlorimuron was used as the residual herbicide in the preplant application in 

place of flumioxazin/chlorimuron, control was also excellent (98%). 

B.2.5.2.1.4. Glyphosate-Resistant Giant Ragweed

Giant ragweed is a summer annual broadleaf weed found in the Midwest and East, but tends to be 

most problematic in the eastern Corn Belt (Johnson et al., 2007). The early emergence, rapid growth 

rate, and large leaf area gives giant ragweed an initial competitive advantage over many other weeds 

and soybean. Dicamba at rates of 0.25 to 0.5 lbs. a.e./acre provides excellent control of glyphosateresistant giant ragweed when applied to plants 3 to 6 inch in height. Control is reduced and 

inconsistent when applications are made to taller plants. Single postemergence applications of 

glyphosate plus dicamba to small plants (3-6 inches in height) have provided excellent control of 

glyphosate-resistant giant ragweed in conventional tillage systems. In no-till systems, preplant

burndown applications of glyphosate plus dicamba plus a preemergence residual herbicide followed 

by an in-crop postemergence application of glyphosate plus dicamba has provided excellent control.

 Results reported by the University of Missouri indicate the importance of application height 

and dicamba rate on control of glyphosate-resistant giant ragweed (Spaunhorst et al., 2011; 

Spaunhorst et al., 2012). Studies conducted in 2011 indicate that dicamba rates of 0.25, 

0.375 and 0.5 lbs. a.e./acre resulted in excellent control of glyphosate-resistant giant ragweed 

(90-95%) plants that were 3-inch and 6-inch in height at the time of application (Spaunhorst 

et al., 2011). Dicamba at 0.5 lbs. a.e./acre provided the highest level of control. These same 

rates of dicamba provided significantly lower levels of control (50-65%) when applied to 

plants that were 12 inches in height. A separate field study conducted in 2011 showed that 

two sequential applications of dicamba (0.25 followed by 0.5 lbs. a.e./acre) to 3-inch plants 

provided 100% control at 21 days after treatment, regardless of whether or not glyphosate 

was included in the treatment (Spaunhorst et al., 2012). Giant ragweed control was reduced 

slightly when the initial postemergence application was made to 9-inch plants. Single 

applications of dicamba (0.5 lbs. a.e./acre) alone provided 96% control of 3-inch plants and 

only 84% control of 9-inch plants. Although a single application of dicamba at a lower rate 

of 0.25 lbs. a.e./acre alone to 3-inch plants provided excellent control (95%), this rate was 

ineffective (62%) on 9-inch giant ragweed. This study also showed that giant ragweed is 

much more sensitive to dicamba than waterhemp. 

 The control of glyphosate-resistant giant ragweed improved with the addition of dicamba to 

postemergence applications of glyphosate compared to glyphosate alone in field studies 

conducted in Ohio in 2008 and 2009 (Johnson et al., 2010). Sequential applications of 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 563 of 946

dicamba (0.25 lbs. a.e./acre) alone provided complete control of glyphosate-resistant giant 

ragweed compared to only 70% control with sequential applications of glyphosate alone.

 Three field trials conducted by the University of Guelph in 2010 and 2011 indicate that the 

use of dicamba in dicamba-glyphosate-tolerant soybean will provide effective control of 

glyphosate-resistant giant ragweed (Vink et al., 2012). Glyphosate plus dicamba (0.25 and 

0.5 lbs. a.e./acre) applied preplant followed by glyphosate plus dicamba (0.25 and 0.5 lbs. 

a.e./acre) postemergence consistently provided 100% control of glyphosate-resistant giant 

ragweed at 7 weeks after treatment. In comparison, glyphosate alone applied preplant, 

postemergence, or sequentially provided 15 to 68%, 40 to 46%, and 54 to 98% control at 7 

weeks after treatment, respectively. Glyphosate plus dicamba (0.5 lbs. a.e./acre) applied 

preplant and postemergence provided 93 to 100% and 95 to 100% control at 7 weeks after 

treatment, respectively.

 The University of Missouri conducted field experiments evaluating various pre-post systems 

containing dicamba for control of glyphosate-resistant giant ragweed in a no-till system 

(Bradley et al., 2012). Systems containing a preplant application of glyphosate plus dicamba 

(0.5 lbs. a.e./acre) plus a preemergence residual herbicide followed by glyphosate plus 

dicamba (0.5 lbs. a.e./acre) provided 100% late season control. The residual herbicides were 

flumioxazin, flumioxazin/chlorimuron, and sulfentrazone/chlorimuron. Complete control 

was achieved whether the application was made to 4-inch or 8-inch plants.

B.2.5.2.1.5. Glyphosate-Resistant Common Ragweed and Kochia

At this time, results have not been published for field studies evaluating the control of glyphosateresistant common ragweed and kochia. Dicamba-glyphosate weed control systems are expected to 

provide excellent control of glyphosate-resistant common ragweed because dicamba has a 90 to 

100% control rating on common ragweed (see Table VIII-17 in the Dicamba-Tolerant Soybean 

MON 87708 petition #10-188-01p). Kochia is not a common or problematic weed species in most 

of the soybean producing states. However, kochia is a problematic weed in western sections of 

Kansas and Nebraska where some soybean is produced. Dicamba has a control rating of 8 out of a 

possible 10 on kochia as a postemergence application in corn (University of Nebraska, 2012). 

B.2.5.2.2. Improved Control of Hard-to-Control Broadleaf Weed Species 

Dicamba use on dicamba-tolerant soybean offers a new management tool for improved control of 

hard-to-control weed species in soybean (Maxwell et al., 2011; Moechnig et al., 2010; Peterson et al., 

2011). Certain problematic broadleaf weed species in certain areas of the U.S. that are naturally 

relatively less sensitive to glyphosate, namely morningglory spp., hemp sesbania, prickly sida, and 

wild buckwheat are generally hard to control with postemergence applications of glyphosate alone. 

Alternative broadleaf postemergence soybean herbicides (ALS and PPO) provide inconsistent or 

less than acceptable control of these problematic broadleaf species in soybean. (Tables A-12 and A13). Populations of common lambsquarters, prickly sida, and black nightshade are resistant to ALS 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 564 of 946

herbicides, and common waterhemp and common ragweed have populations resistant to PPO 

herbicides (Heap, 2012). Postemergence applications of the glyphosate plus dicamba tank mixture 

will improve the control of these hard-to-control broadleaf weed species compared to glyphosate 

alone. Also, the control with the glyphosate plus dicamba mixture will often exceed the control of 

glyphosate mixtures with other commercial standards on certain of these weed species.

 Field studies conducted from 2007 and 2008 indicate that glyphosate plus dicamba (0.25 lbs. 

a.e./acre) provided 98-99% control of morningglory species compared to glyphosate alone at 

90-93% control (Johnson et al., 2010). The researchers noted that dicamba improved the 

consistency of control of morningglory. Results from additional field studies conducted by 

the University of Illinois in 2011 show that a tank mixture of glyphosate plus dicamba (0.5 

lbs. a.e./acre) applied postemergence provided improved late season control of tall 

morningglory (98%) compared to the control with glyphosate alone at 63% (Maxwell et al., 

2011). 

 Studies conducted at Kansas State University have demonstrated similar improvements in 

control of ivyleaf morningglory in weed control systems that incorporate dicamba (Peterson 

et al., 2011). A weed control system of glyphosate preplant followed by two in-crop 

postemergence applications of glyphosate plus dicamba (0.25 lbs. a.e./acre) provided 94% 

control of ivyleaf morningglory while the weed control system without dicamba provided 

78% control. The addition of dicamba to glyphosate also resulted in improved control of 

ivyleaf morningglory in a Texas experiment compared to glyphosate alone (Cogdill and 

Chandler, 2012). 

 Studies conducted in Louisiana show that dicamba will improve control of hemp sesbania 

and prickly sida, two common broadleaf weeds in the South (Bauerle et al., 2012). Dicamba 

preemergence followed by glyphosate plus dicamba postemergence provided 98-100% 

control of pigweed, hemp sesbania, and prickly sida. Hemp sesbania control was improved 

when dicamba (0.5 lbs. a.e./acre) was added to preemergence applications of residual 

herbicides: metolachlor/fomesafen (33 to 73%), metolachlor (50 to 90%), acetochlor (23 to 

85%), flumioxazin/metribuzin (43 to 93%), pyroxasulfone (15 to 72%), and 

chlorimuron/metribuzin (52 to 92%). 

 Wild buckwheat is a hard-to-control broadleaf weed species in soybeans in the Plains region 

of the U.S. Dicamba (0.25 lbs. a.e./acre) plus glyphosate applied as a no-till burndown 

application provided 98% and 82% control of wild buckwheat at 30-35 days after treatment 

in South Dakota State University trials in 2008 and 2009, respectively (Moechnig et al., 

2010). In comparison, a burndown application of sulfentrazone/cloransulam plus 

glyphosate provided 90 and 95% control in 2008 and 2009, respectively. All two-pass incrop postemergence systems of glyphosate alone or glyphosate plus dicamba resulted in 

nearly complete control of wild buckwheat.
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Table B-12. Common Broadleaf Weed Responses to Preplant Burndown Herbicides

Common Broadleaf Weeds1,2

Herbicide/Application LQ CR GR SW CC

M, 

SP CT RC AL HV MT PL

DN, 

HB DL CG

Spring Preplant Application

2,4-D (0.5 lb/1.0 lb) - - - - - 9 -/6 6/8 -/7 6/8 8/9 8/9 -/8 6/7 9/9

Dicamba 9 9 9 9 6 7 - 9 8 8 7 9 - 7 -

Dicamba + 2,4-D 9 9 9 9 6 9 6 9 8 9 9 9 - 8 9

Glyphosate 8 9 8 7 7 8 6 7 6 6 6 8 - 7 7

Glyphosate + 2,4-D 9 9 9 8 7 9 6 8 8 8 8+ 9 6 8 9

Glyphosate + Canopy 8 9 9 9 7 8 6 7 6 6 8 8+ 9 8+ 9

Glyphosate + Canopy + 2,4-D 9 9 9 9 7 9 6 8 8 8 9 9 9 8+ 9

Glyphosate + Gangster + 2,4-D 9 9 9 9 7 9 6 8 8 8 9 9 8 8 9

Glyphosate + Python + 2,4-D 9 9 9 8 7 9 6 8 8 8 9 9 6 8 9

Glyphosate + Scepter + 2,4-D 9 9 9 8 7 9 6 8 8 8 8+ 9 6 8 9

Gly + Sonic/Authority First + 2,4-D 9 9 9 9 7 9 6 8 8 8 9 9 8 8 9

Glyphosate + Valor + 2,4-D 9 9 9 8 7 9 6 8 8 8 8+ 9 8 7 9

1All weed control ratings are from the 2009 Weed Control Guide for Ohio and Indiana – Weed Responses to Burndown Herbicides, Ohio State University and Purdue 

University (Loux et al., 2009). Weed control ratings for weeds are: 9 = 90% to 100%, 8 = 80% to 90%, 7 = 70% to 80%, 6 = 60% to 70%, and - = less than 60% 

control, not recommended. Ratings assume the herbicides are applied in the manner suggested in the guidelines and according to the label under optimum growing 

conditions.

2Weed species: LQ = lambsquarters, CR = common ragweed, GR = giant ragweed, SW = annual smartweed, CC = common chickweed, M & SP = mustard and 

shephard’s purse, CT = Canada thistle, RC = red clover, AL = alfalfa, HV = hairy vetch, MT = marestail, PL = prickly sida, DN & HB = deadnettle & henbit, DL = 

dandelion, and CG = crested groundsel
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Table B-13. Common Broadleaf Weed Responses to Dicamba Compared to Labeled Postemergence Herbicides in Soybean 

Production

Common Broadleaf Weeds1,2

Herbicide/Application BN CB CR GR HS LQ MG PA PW PS SP SW VL WH

Postemergence

Bentazon - 9 7 6 4 7 2-9 4 - 8 0 9 8+ -

Chlorimuron - 9 8 7+ 8 - 8-9 6 9 2 7 8 8 -

Cloransulam - 9 9 9 3 - 8-9 2 - 2 7 8 9 -

Chlorimuron/thifensulfuron - 9 8 7+ NA 8 NA NA 9 NA NA 9 9 -

Dicamba3 8 9 9 9 9 8 9 9 8 8 8 8 7+ 8

Flumiclorac - 7 7 - NA 7 NA NA 7 NA NA - 9 7

Fomesafen 8 7 8+ 8 9 - 8-9 8 9 2 3 7 6 9

Glyphosate 8 9 8+ 8 7 8 7-9 9 9 7 8 8 8 8

Glyphosate/imazethapyr 9 9 8+ 8+ NA 8+ NA NA 9 NA NA 9 9 8

Imazamox 9 8 7 8 NA 8 NA NA 9 NA NA 8 9 -

Imazethapyr 9 9 6 7 0 6 7-9 6 9 6 0 9 9 -

Lactofen 8+ 8 9 8 9 - 8-9 8 9 8 5 6 7 9

Thifensulfuron - 6 - - NA 8 NA NA 9 NA NA 8 9 -

1All weed control ratings except for HS, MG, PA, PS, and SP are from the 2009 Weed Control Guide for Ohio and Indiana – Ohio State University and Purdue 

University (Loux et al., 2009). Ratings for HS, MG, PA, PS, and SP are from the 2009 Weed Control Guidelines for Mississippi, Mississippi State University (MSU, 

2010), except for dicamba ratings for PA are from the 2010 Weed Control Manual for Tennessee (University of Tennessee, 2010). Weed control ratings for weeds, 

except HS, MG, PA, PS, and SP, are: 9 = 90% to 100%, 8 = 80% to 90%, 7 = 70% to 80%, 6 = 60% to 70%, and - = less than 60% control, not recommended. 

Weed control ratings for HS, MG, PA, PS, and SP are: 9-10 = excellent, 7-8 = good, 4-6 = fair, 0-3 = none to slight. Ratings assume the herbicides are applied in the 

manner suggested in the guidelines and according to the label under optimum growing conditions. NA denotes not available.

2Weed species: BN = black nightshade, CB = cocklebur, CR = common ragweed, GR = giant ragweed, LQ = lambsquarters, MG = morningglory spp., HS = hemp 

sesbania, PA = palmer and spiny pigweed, PW = pigweed, PS= prickly sida, SP = sicklepod, SW = smartweed, VL = velvetleaf, and WH = waterhemp 

3Weed control ratings for dicamba are from postemergence applications in corn
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B.2.5.2.3. Crop Tolerance

Weed management systems utilizing dicamba-glyphosate-tolerant soybean have proven very 

effective in controlling important problematic weed species in soybean. Weed control systems must 

display excellent crop tolerance to the herbicide to allow soybean to reach their full yield potential. 

Dicamba-glyphosate-tolerant soybean provides excellent crop tolerance to dicamba and glyphosate 

applied preemergence and in-crop postemergence. Dicamba displayed excellent tolerance in weed 

control systems that include sequential preemergence and in-crop postemergence applications of 

dicamba or in systems including two sequential in-crop postemergence applications of dicamba. 

Many of the commercial herbicide standards for postemergence broadleaf weed control in soybeans 

exhibit fair to poor crop tolerance ratings, namely acifluorfen, chlorimuron, fluthiacet, fomesafen, 

and lactofen (see Table VIII-9 in the Dicamba-Tolerant Soybean MON 87708 Petition #10-188-

01p).

A total of 35 separate field experiments were conducted on dicamba-glyphosate-tolerant soybean in 

the Midwest, Midsouth, and Southeastern soybean growing regions of the U.S. in 2010 and 2011 

that included visual evaluations of crop tolerance to dicamba applications. No visual symptoms of 

crop injury such as epinasty, leaf malformation, leaf cupping, stunting, or chlorosis to soybean were 

reported in any of these studies from applications of dicamba or dicamba tank mixtures with 

glyphosate. 

Dicamba-glyphosate-tolerant soybeans demonstrated excellent crop tolerance to preemergence 

applications of dicamba at 0.5 to 1.0 lbs. a.e./acre in 11 experiments conducted in the Midsouth and 

Southeastern states (Bauerle, et al., 2012; Bernards et al., 2011; Steckel et al., 2012; York et al., 2012). 

No crop injury was reported with any dicamba applications in these experiments. Excellent crop 

tolerance was displayed to single in-crop postemergence applications of dicamba at rates up to two 

to three times the proposed use rate (1.0 to 1.5 lbs. a.e./acre) in experiments conducted in Kansas 

and Mississippi in 2010 and 2011 (Peterson et al., 2011; Edwards et al., 2012).

As presented in Table B-11, the proposed weed control system recommendations for dicambaglyphosate-tolerant soybean in conservation tillage recommend preemergence followed by in-crop 

postemergence applications of dicamba, or sequential in-crop postemergence applications of 

dicamba in conventional tillage practices. Dicamba-glyphosate-tolerant soybean provides excellent 

crop tolerance in these systems. No crop injury was reported in studies evaluating preemergence 

applications of dicamba (0.5 to 1.0 lbs. a.e./acre) followed by postemergence applications of 

dicamba (0.5 lbs. a.e./acre) (Bauerle et al., 2012; Stebbing et al., 2011; Steckel and Montgomery, 

2008; Steckel et al., 2012 York et al., 2012). No crop injury was reported when flumioxazin or 

glyphosate was added to the preemergence application or glyphosate was added to the 

postemergence application. Numerous studies were conducted to evaluate the efficacy of two 

sequential in-crop postemergence applications of dicamba on dicamba-glyphosate-tolerant soybean 

(Maxwell et al., 2011; Spaunhorst et al., 2011 and 2012; Bradley et al., 2012; Steckel et al., 2012; 

Eubank et al., 2012). No crop injury was reported from sequential in-crop postemergence 

applications of dicamba up to 0.5 lbs. a.e./acre with any of these experiments regardless of the 

absence or presence of glyphosate in the treatment. 

B.2.5.2.4. Application Flexibility With Dicamba in Dicamba-Glyphosate-Tolerant Soybean

Dicamba-glyphosate-tolerant soybean will facilitate a wider window of application for dicamba in 

soybean and application flexibility for both preemergence and postemergence applications in 
Monsanto Company 10-SY-210U / 12-CT-244U-S 

soybean. Current labeled uses of dicamba in soybean are limited to early preplant and late 

postemergence (preharvest) applications. To avoid soybean injury, significant planting restrictions 

exist currently in soybean for preplant applications of dicamba. The waiting interval prior to 

planting soybeans is 28 days following application of a maximum dicamba rate of 0.5 lbs. a.e. per 

acre and a minimum accumulation of one inch of rainfall or overhead irrigation (Clarity Herbicide 

label; CDMS, 2012). University weed control specialists indicate that the dicamba-tolerant soybean 

technology will be important because it will enable preplant and preemergence applications of 

dicamba without a preplant interval for control of existing weeds in no-till cropping systems 

(Peterson et al., 2011, Steckel et al., 2012).

To support the introduction of dicamba-glyphosate-tolerant soybean, Monsanto has submitted an 

application to U.S. EPA to amend Registration Number 524-582, a DGA salt formulation, to 

remove all preemergence planting restrictions (intervals and rainfall) and to allow in-crop 

postemergence applications of dicamba to dicamba-tolerant soybean up to and including the R1/R2 

growth stage of soybean. Once approved, growers would be authorized to apply dicamba alone or 

tank mixed with glyphosate for preplant or postemergence in-crop applications on dicambaglyphosate tolerant soybean. Dicamba would also be authorized to be applied preemergence up to 

day of crop emergence at up to 1.0 lb. a.e. per acre and postemergence with two sequential 

applications at up to 0.5 lb a.e. per acre up to and including the R1/R2 growth stage of soybean. 

Dicamba will have the added flexibility to be applied using water or sprayable fertilizer as a carrier. It 

can also be tank mixed and applied with insecticides or other herbicides as needed due to its 

excellent compatibility with these products. 

B.2.5.2.5. Proactive program for weed resistance management 

With the potential, in certain areas of the U.S., for continued selection pressure for new glyphosateresistant weed species and the spread of current glyphosate-resistant weed species, additional weed 

management tools are needed to slow the development and spread of these resistant weed species. 

University weed control specialists involved with the evaluation of dicamba-glyphosate-tolerant 

soybean indicate that this new technology would provide an additional management tool and modeof-action to control glyphosate-resistant weeds (Johnson et al., 2010; Edwards et al., 2012; Maxwell 

et al., 2011; Peterson et al., 2011; York et al., 2012). In addition, this new dicamba technology will 

reduce the dependence on PPO-inhibiting herbicides, thereby reducing the selection pressure to 

glyphosate and to PPO-inhibiting herbicides such as fomesafen, acifluorfen, and lactofen (York et 

al., 2012). As recommended by weed scientists, the proposed weed management recommendations 

include the use of a preemergence residual herbicide to further reduce selection pressure and 

improve the sustainability of the dicamba-tolerant soybean technology (Table B-11). University weed 

control specialist stress the importance of using other herbicides with different modes of action and 

the use of residual preemergence herbicides to maximize the long-term sustainability and utility of 

the dicamba-tolerant technology (Stebbing et al., 2011).

B.2.5.2.6. Preserves conservation tillage benefits 

The benefits of conservation tillage are well known, namely reduced labor, savings of time and fuel, 

improved soil health, reduced soil erosion, and improved water quality – as well as air quality 

benefits from reduced use of farm machinery (CTIC, 2012a; Price et al., 2011). Conservation tillage 

systems are well established in soybean production, with 62% and 76% of the full season and double 

crop soybean acres, respectively, utilizing some form of conservation tillage (CTIC, 2012b). No-
Monsanto Company 10-SY-210U / 12-CT-244U-S 

tillage systems are used on 39% and 72 % of full season and double crop soybean, respectively. 

Glyphosate-tolerant soybean has been a primary enabler for continued adoption of conservation 

tillage systems and for the success of USDA Natural Resource Soil Conservation (NRCD) programs 

(CAST, 2012). Weed resistance to glyphosate in certain areas of the U.S. is a threat to soil 

conservation gains in some situations (CAST, 2012; Price et al., 2011). In particular, Palmer 

amaranth and horseweed are very difficult to manage in no-tillage systems with currently available 

herbicide systems (Price et al., 2011; (Steckel and Montgomery, 2008)). The postemergence options 

for effective control of Palmer amaranth and horseweed are limited in soybean (Steckel and 

Montgomery, 2008; Steckel et al., 2012). Dicamba-glyphosate-tolerant soybean will assist in 

preserving the use of conservation tillage and the benefits growers and the environment realize from 

utilizing these systems by enabling effective management of glyphosate-resistant weed species and 

other hard-to-control weeds in the areas of the U.S. where they occur. 

Dicamba applications in dicamba-glyphosate-tolerant soybean provide excellent control of 

glyphosate-resistant weeds and other problematic weeds in no-tillage soybean (Bernards et al., 2011; 

Stebbing et al., 2011; Bradley et al., 2012; Steckel et al., 2012; York et al., 2012). This, combined 

with the application flexibility of the dicamba-glyphosate-tolerant soybean system, will benefit notillage and other conservations tillage systems for soybean, and enable growers to return to 

conservation tillage systems that may have abandoned these systems because of inadequate control 

of glyphosate-resistant weeds in certain areas of the U.S. 

B.2.5.3. Conclusion

Dicamba-glyphosate-tolerant soybean will enable an additional weed management tool for effective 

and sustainable weed management in soybean production. Dicamba-glyphosate-tolerant soybean 

will allow growers to use dicamba and glyphosate herbicides in a diversified weed management 

program to control a broad spectrum of grass and broadleaf weed species. Dicamba tolerance will 

facilitate a wider window of application for dicamba in soybean and application flexibility for both 

preemergence and postemergence applications in soybean compared to current labeled uses of 

dicamba in soybean. A significant number of field studies conducted by university weed control 

specialist in the major soybean production regions from 2007 to 2011 have lead to the development 

of weed management system recommendations for dicamba-glyphosate-tolerant soybean. These 

systems recommendations will provide for effective and sustainable management of glyphosateresistant weed species including Palmer amaranth, waterhemp, giant ragweed, and horseweed. In 

addition, weed control systems in dicamba-glyphosate-tolerant soybean will improve control of 

certain hard-to-control broadleaf weed species which are known to be problematic in soybean 

production such as morningglory, hemp sesbania, prickly sida, and wild buckwheat, compared to 

glyphosate alone. Dicamba-glyphosate-tolerant soybean weed management systems provide 

excellent crop tolerance as evidenced by no reports of visual crop injury symptoms in 35 field 

experiments evaluating dicamba applications at and above the maximum proposed use rates of 

dicamba for both preemergence and postemergence applications. 

Dicamba-glyphosate-tolerant soybean provides a new technology with an additional mode-of-action 

to control glyphosate-resistant weed species and provide an easy means to incorporate an additional 

herbicide mode-of-action in soybean production practices. In addition, this technology has the 

potential to reduce the dependence on PPO-inhibiting herbicides, thereby reducing the selection 

pressure and mitigating the potential for the development of weed resistance to PPO-inhibiting 

herbicides. Weed resistance to glyphosate in certain areas of the U.S. is a threat to soil conservation 
Monsanto Company 10-SY-210U / 12-CT-244U-S 

gains in recent years. Dicamba-glyphosate-tolerant soybean provides excellent control of 

glyphosate-resistant weeds and other problematic weeds in no-tillage soybean. This performance in 

no-tillage systems and the application flexibility facilitated by dicamba-glyphosate-tolerant soybean 

will help preserve conservation tillage usage and its well documented environmental and economic 

benefits in soybean.

All of these benefits strongly support the need for dicamba-tolerant soybean as a new and beneficial 

tool for soybean growers in the U.S.

B.3. DGT Cotton

B.3.1. Introduction

This section addresses weeds and weed management in cotton production, followed by a discussion 

of herbicide-resistant weeds and the benefits of DGT cotton production. 

B.3.2. Weeds in Cotton

Across the Cotton Belt many annual and perennial weeds occur, resulting in economic damage to 

cotton yield, fiber quality, and economic returns. Barnyardgrass, crabgrass, pigweed spp. (including 

Palmer amaranth), morningglory spp., common cocklebur, and common lambsquarters are common 

annual weed species in almost all cotton-growing regions. Johnsongrass, bermudagrass, and 

nutsedge are common perennial weed species. Nightshade spp. and groundcherry are more 

common in the Southwest and West regions. Palmer amaranth, morningglory spp., and nutsedge 

spp. are often reported as the most problematic weed species in cotton (Webster et al. 2009). Tables 

B- 14 through B-17 summarize the most common weeds for each of the four major cotton growing 

regions (Southeast, Midsouth, Southwest and West).

Table B-14. Common weeds in Cotton Production in the Southeast Region of the U.S.1,2

Crabgrass spp. (6) Pigweed spp (3) Crowfootgrass (1)

Morningglory spp (6) Common cocklebur (2) Horseweed (marestail) (1)

Prickly sida (5) Common lambsquarters (2) Jimsonweed (1)

Florida pusley (4) Common ragweed (2) Johnsongrass (1)

Nutsedge spp. (4) Florida beggarweed (2) Smartweed spp. (1)

Sicklepod (4) Palmer amaranth (2) Spurge spp (1)

Broadleaf signalgrass (3) Texas millet (2) Volunteer peanut (1)

Goosegrass (3) Bermudagrass (1)

1 Source: (Webster et al. 2009). 

2 Number provided in parenthesis is the number of states out of the six total states (AL, FL, GA, NC, SC, & VA) in 

the Southeast Region reporting each weed as one of the ten most common weeds.
Monsanto Company 10-SY-210U / 12-CT-244U-S 

Table B-15. Common weeds in Cotton Production in the Midsouth Region of the U.S.1,2

Morningglory spp (5) Velvetleaf (3) Common cockleburr (1)

Broadleaf signalgrass (4) Barnyardgrass (2) Cutleaf evening-primrose (1)

Crabgrass spp (4) Horseweed (marestail) (2) Goosegrass (1)

Nutsedge spp (4) Johnsongrass (2) Hemp sesbania (1)

Prickly sida (4) Palmer amaranth (2) Henbit (1)

Spurge spp (4) Bermudagrass (1) Spurred anoda (1)

Pigweed spp (3) Browntop millet (1)

1 Source: (Webster et al. 2005; Webster et al 2009) Webster et al., 2005 (MS & TN); Webster et al., 2009 (AR, LA, & 

MO).

2 Number provided in parenthesis is the number of states out of the five total states (AR, LA, MS, MO, & TN) in the 

Midsouth Region reporting each weed as one of the ten most common weeds.

Table B-16. Common weeds in Cotton Production in the Southwest Region of the U.S.1,2

Johnsongrass (4) Pigweed spp (2) Smartweed (1)

Nutsedge spp (4) Russian thistle (2) Smellmelon (1)

Common cockleburr (3) Barnyardgrass (1) Spurred anoda (1)

Palmer amaranth (3) Bermudagrass (1) Red Sprangletop (1)

Silverleaf Nightshade (3) Bindweed, field (1) Sunflower (1)

Common lambsquarters (2) Foxtail spp (1) Texas blueweed (1)

Large Crabgrass (2) Groundcherry spp (1) Texas millet (2)

Devil’s claw (2) Kochia (1) Velvetleaf (1)

Morningglory spp (2) Horseweed (marestail) (1) Woolyleaf bursage (1)

Mustard spp (2) Shepardspurse (1)

1 Source: OK - Webster et al., 2009; KS – Dr. Stewart Duncan, Kansas State University – Personal Communication 

11/4/2010; NM – Dr. Jamshid Ashigh, New Mexico State University – Personal Communications 11/12/2010; TX 

– Dr. Wayne Keeling and Dr. Gaylon Morgan, Texas A&M University - Personal communications 11/4/2010.

2 Number provided in parenthesis is the number of states out of the four total states (KS, OK, TX, & NM) in the 

Southwest Region reporting each weed as one of the ten most common weeds.
Monsanto Company 10-SY-210U / 12-CT-244U-S 

Table B-17. Common weeds in Cotton Production in the West Region of the U.S.1,2

Barnyardgrass (2) Common lambsquarters (1) Silverleaf Nightshade (1)

Morningglory spp (2) Johnsongrass (1) Palmer amaranth (1)

Sprangletop (2) Junglerice (1) Common Purslane (1)

Bermudagrass (1) Nutsedge spp (1) Horse Purslane (1)

Field Bindweed (1) Pigweed spp (1) Volunteer corn (1)

Cupgrass, southwestern (1) Black Nightshade (1)

Groundcherry spp (1) Hairy Nightshade (1)

1 Source: AZ – Bill McCloskey, University of Arizona – Personal Communication 11/5/2010; CA – Steven Wright, 

University of California - Personal Communication 11/16/2010.

2 Number provided in parenthesis is the number of states out of the two total states (AZ & CA) in the West Region 

reporting each weed as one of the ten most common weeds.

B.3.3. Weed Management in Cotton

Weed control in cotton is essential to maximize both yield and quality of cotton fiber. The slow 

early growth of cotton does not permit the crop to aggressively compete against weed species that 

often grow more rapidly and utilize the available water, nutrients, light, and other resources for 

growth (Smith and Cothren 1999). Cotton yields can be reduced substantially if weeds are 

uncontrolled. Palmer amaranth can cause yield losses as high as 54% (Morgan, et al. 2001) and 

johnsongrass and barnyardgrass can reduce yields by 90% and 98%, respectively (Vargas, et al. 

1996). Based on 2005 data, not using herbicides in cotton would result in an increased production 

cost of approximately $2.3 billion annually and an estimated yield loss of 27% (Gianessi and Reigner 

2006). 

Weed-crop competition studies have demonstrated that the control of weeds during the first four to 

eight weeks after cotton planting is critical as weeds compete against the crop for water, nutrients, 

light and other resources necessary for growth (Smith and Cothren 1999). The primary weed 

competition factors affecting yield loss potential are the weed species, weed density, and the 

timing/duration of weed competition. Cotton emergence and above ground growth is relatively 

slow during the first few weeks after planting, and does not permit the crop to aggressively compete 

against often more rapidly developing weed species (Smith and Cothren 1999). In addition, cotton 

is primarily planted using wide row spacing which delays crop canopy closure until layby stage of 

cotton and extends the window of weed-crop competition. 

While late-season infestations may not impact yield, they reduce harvesting efficiency, contribute to 

the weed seed bank and lower the lint grade (McWhorter and Bryson 1992; Vargas et al. 1996). 

Weeds can also increase cotton disease and insect management issues because certain weed species 
Monsanto Company 10-SY-210U / 12-CT-244U-S 

can be a host for pathogens, such as Rhizoctonia and Verticillium, and harbor insects such as lygus 

bugs. 

The most effective weed management programs in cotton use diversified weed management, a 

combination of cultural, mechanical, and/or herbicide control practices, instead of relying on one 

particular method of weed control (Beckie, et al. 2011; University of California 2009; Vargas et al. 

1996). Herbicide application practices that are compatible with diversified weed management 

include the use of several herbicides with different modes-of-action, either within or across seasons, 

applying herbicides at the labeled rate and at the correct timing, and proper application of the 

herbicide. Cultural and mechanical practices can also be important components of an effective 

diversified weed management program (Ashigh et al. 2012). Cultural practices such as crop rotation, 

use of optimal planting dates, and the use of cover crops, when implemented, can increase the 

crop’s ability to compete with weeds. Crop rotation (limiting continuous cotton planting), in 

conjunction with other weed control methods, can play a role in the overall weed spectrum and can 

drastically reduce the overall weed population observed (Smith and Cothren 1999). Approximately 

38% of the total cotton acres are post-plant cultivated for weed control and in conventional tillage 

systems, and over 50% of cotton acres are cultivated for weed control with as many as five tillage 

operations occurring after emergence to harvest (USDA-ERS 2012c. Spring preplant or fall 

postplant tillage and in-crop shallow cultivation can effectively reduce the competitive ability of 

weeds. A consequence of in-crop cultivation for weed control is that tillage equipment can damage 

crop roots or apical meristem, causing soil moisture loss. More recently, cotton growers in certain 

areas of the U.S. have begun utilizing more hand-weeding to control glyphosate-resistant Palmer 

amaranth in fields. For example, Georgia cotton growers have increased hand-weeding from 17% 

of the state cotton acreage in 2000-2005 to 52% of the acreage in 2006-2010. Hand-weeding has a 

current cost of $23 per acre (Sosnoskie and Culpepper 2012). A survey of Georgia cotton growers 

conducted in 2010 found that 92% of growers spent $16 million on hand-weeding 53% of the total 

Georgia cotton crop; similarly, at least 20% of the cotton acres in Tennessee were hand-weeded at 

cost of more than $3 million (Culpepper, et al. 2011). 

The planting of winter cover crops can be utilized as part of a diversified weed management 

strategy. The planting of cover crops, such as grasses, legumes, or small grains can protect and 

improve soil quality, help reduce erosion, serve as surface mulch in no-till cropping practices, and 

provide habitat for beneficial insects (Guerena and Sullivan 2003; Hitt and Roos 2007; Mannering, et 

al. 2007). Small grain crops such as rye are commonly used as a cover crop; incorporating rye or 

oats as a cover crop have been shown to suppress Palmer amaranth germination and growth (Price, 

et al. 2011). However, the planting of cover crops in general incurs additional costs to the grower 

and therefore cover crops are not typically a major weed management practice utilized in cotton 

production systems (Singer 2006). 

Herbicides are used on essentially all (>99%) cotton acres, and in 2011 approximately 39 million 

pounds of herbicides were applied pre- or postemergence in cotton production (Brookes and 

Barfoot 2012; Monsanto 2012). According to 2010 market data107, there were approximately 46.3 

 

107 Monsanto Company. 2011. Farmer Survey Data. St. Louis, MO.
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million herbicide-treated cotton acres. Herbicides were applied to 21.8 million acres prior to the 

planting or emergence of cotton (preemergent) and to 24.5 million acres after the emergence of 

cotton (postemergent). For clarification, the market survey data counts one treated acre as the 

application of one active ingredient (a.i.) one time to an acre. If the same a.i. is applied a second 

time to that same acre or if two a.i.s are applied, it counts as two treated acres. USDA reports that 

11.0 million acres of cotton were planted in 2010,108 so that the 46.3 million herbicide-treated cotton 

acres means that on average each planted acre received at least 4 herbicide treatments. Cotton acres 

also received on average four treatments with herbicides during the 2011 growing season (USDAERS 2012). 

Of these treatments, 50% (23.3 million acres) were made with glyphosate herbicides, and the 

remaining 50% of treatments were made with more than 25 other active ingredients. The number of 

glyphosate applications on an average cotton acre was between 2 and 3 applications per year at an 

average rate of 2.0 pounds acid equivalent (a.e.) of glyphosate active ingredient per acre per crop 

year. 

Herbicide-tolerant cotton is planted on the majority of U.S. cotton acres (73% in 2011), which 

allows for the postemergence in-crop use of glyphosate for control a broad spectrum of weeds. 

Glyphosate is the most widely-used herbicide in cotton, applied on 91% of cotton acres with an 

average of 2.4 applications per growing season (Monsanto 2012). In 2010, between 49 and 76% of 

the growers who plant glyphosate-tolerant (GT) cotton applied non-glyphosate herbicides prior to 

planting, at planting, or postemergence. Percentages varied among cropping systems, with 76% of 

GT cotton in a rotation system with GT soybean receiving non-glyphosate herbicide applications, 

whereas non-glyphosate herbicides were only applied 49% of the time in continuous cotton 

cropping systems (Prince, et al. 2011a). Non-glyphosate herbicides with different modes-of-action 

are also frequently used to provide residual weed control, improve control on certain weed species, 

and extend weed control or control resistant weed species (Prince et al. 2011a). The non-glyphosate 

herbicides applied on cotton in 2011, included ALS inhibitors (trifloxysulfuron, pyrithiobac), 

longchain fatty acid inhibitors (acetochlor, metolachlor), microtubule inhibitors (pendimethalin, 

trifluralin), PSII inhibitors (prometryn, fluometuron, diuron), PPO inhibitors (flumioxazin, 

fomesafen), synthetic auxins (2,4-D, dicamba), glufosinate, MSMA and paraquat (Monsanto 2012).

In 2010, dicamba-treated acres in cotton accounted for only 0.85 million acres, or 3.9% of the total 

preemergent treated acres.109 This is primarily because dicamba is phytotoxic to current cotton 

varieties and is currently only labeled for application at timings that avoid contact with the growing 

plant, such as preplant treatments prior to planting, depending on rate and rainfall.

Over 30 different herbicide active ingredients are registered and available for use by cotton growers 

to control weeds. The ten most widely used alternative herbicides in cotton in 2010 are listed in 

Table B-18, compared to 2007 use. Integration of DGT cotton into the glyphosate-toleran cotton 

 

108 USDA Statistics for crops and geographic regions are available at http://www.nass.usda.gov/index.asp.

109 Monsanto Company. 2011. Farmer Survey Data. St. Louis, MO.
Monsanto Company 10-SY-210U / 12-CT-244U-S 

system and the subsequent use of dicamba will result in the displacement of some currently used, or 

foreseeable future use herbicides, and therefore the properties of these alternative herbicides are 

summarized in this section to provide a baseline for comparison to dicamba use on DGT cotton.

Table B-18. Ten Most Widely Used Alternative Herbicides in U.S. Cotton Production

Herbicide

2007 Applications 

(million lbs)1

2010 Applications 

(million lbs)1

Trifluralin 2.8 3.1

Diuron 1.3 1.3

Pendimenthalin 1.3 1.2

S-metolachlor 0.6 1.1

Prometryn 0.6 0.4

2,4D, dimethylamine salt 0.3 0.4

Fluormeturon 0.3 0.4

MSMA 0.4 0.3

Fomesafen 0.05 0.2

2,4-D, ethylhexyl ester 0.1 0.1

1 USDA-NASS, 2013

Table B-19 lists the most-widely used cotton herbicide products. Based on 2010 market data, the 

a.i.s listed in Table B-19 account for 46.2 million treated acres or 99.7% of the total herbicidetreated cotton acres. Table B-19 also summarizes some key information about the alternative 

herbicide products that are evaluated in this Environmental Report, such as signal word, re-entry 

interval, use rates, and label warnings or special directions. 

Table B-19 lists further information about the herbicidal a.i.s used in cotton, such as the registration 

date, registration review status, U.S. EPA Registration Eligibility Decision (RED) date, where the 

tolerance information can be found, whether it is a reduced risk pesticide, and whether it is a 

restricted use pesticide.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 576 of 946

Table B-19. Dicamba and Alternative Registered Cotton Herbicides.

Representative 

Brand

(EPA Reg. 

No.)

Active 

Ingredient

2010 use 

area 3

For a.i.

(K acres / 

%) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicat

ion)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special 

Directions

Clarity (7969-137) Dicamba 855 / 1.8 Caution 4.0 lb a.e./gal 24 hr 1.0 1 2.0 1 Known to leach; 50-foot buffer to wells; 

Runoff advisory; Drift advisory; Statespecific limitations; Soil type limitations; 

Maximum crop rotation interval 3 – 6 

months.

Ignite (264-829) Glufosinate 

ammonium

1,297 / 2.8 Warning 2.34 lb/gal 12 hr 0.79 1.59 Toxic to vascular plants; May have runoff 

potential; Drift advisory; 70-day cotton 

PHI; Little or no activity in soil; Not in 

Hawaii or S. Florida.

Roundup 

WeatherMAX 

(524-537) 

Glyphosate 23,345 / 50.4 Caution 4.5 lb a.e./gal 4 hr 3.71 5.96 Weed resistance advisory; Drift advisory; 

7-day cotton PHI.

Treflan HFP 

(62719-250)

Trifluralin 4,098 / 8.8 Caution 4.0 lb/gal 12 hr 2 2 Extremely toxic to freshwater, estuarine, 

and marine fish and invertebrates; Some 

crops have long rotational interval (18 - 20 

mos.); 90-day cotton PHI.

Direx 4L (352-678) Diuron 2,110 / 4.6 Caution 4 lb/gal 12 hr 1.6 2.2 Drift Advisory; Crop rotation intervals of 

12 months common; State-specific 

limitations; Soil type limitations; Do not 

feed treated foliage to livestock.

Prowl 3.3 EC Pendimethali

n

2,010 / 4.3 Caution 3.3 lb/gal 24 hr 2 2 Toxic to fish; Endangered plant species 

buffer required; Drift and runoff may be 

hazardous to aquatic organisms; Long (14 -

24 mos) crop rotation intervals for some 

crops; 60-day cotton PHI; State-specific 

limitation; Soil-type limitations; Do not 

feed treated foliage to livestock.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 577 of 946

Representative 

Brand

(EPA Reg. 

No.)

Active 

Ingredient

2010 use 

area 3

For a.i.

(K acres / 

%) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicat

ion)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special 

Directions

Valor SX (59639-

99) 

Flumioxazin 1,835 / 4.0 Caution 0.51 lb/lb 12 hr 0.06 0.13 Toxic to non-target plants & aquatic 

invertebrates; Runoff advisory; 40-foot 

aerial buffer to adjacent crops or water 

bodies; 12-month rotation interval 

common; Cotton injury possible; Do not 

feed treated foliage to livestock; 60-day 

cotton PHI.

Staple (352-576) Pyrithiobacsodium1,689 / 3.6 Warning 0.85 lb/lb 24 hr 0.1 0.13 Highly toxic to non-target plants; Drift 

warnings; Cotton injury possible; Weed 

resistance advisory; 60-day cotton PHI; 

State-specific limitations (Staple LX); 10 –

12 month rotation intervals.

Staple LX (352-

613)

PyrithiobacsodiumCaution 3.2 lb/gal 4 hr 0.1 0.13

Dual Magnum 

(100-816)

SMetolachlor1,492 / 3.2 Caution 7.62 lb/gal 24 hr 1.27 2.48 Potential to leach; Potential for runoff; 

Ground & surface water advisory; State 

specific limitations; Soil type limitations; 

Swath adjustment 300 - 400 ft to avoid 

non-target plant injury; 80- to 100-day 

cotton PHI; Do not feed treated foliage to 

livestock.

MSMA 6 Plus 

(19713-42) 

Monosodium 

Metharsonate

1,451 / 3.1 Caution 6 lb/gal 12 hr 1.88 3.75 50-foot buffer around all permanent water 

bodies; Drift warning about adjacent crops 

and sensitive areas; State specific 

limitations; No preplant cotton treatment; 

Do not feed treated foliage to livestock.

Barage HF (5905-

529)

2,4-D 

Ethylhexyl 

Ester (EHE)

1.421 / 3.1 Caution 4.7 lb a.e./gal 12 hr 2.35 2 4.7 2 Toxic to aquatic invertebrates; Drift may 

adversely affect non-target plants or 

invertebrates; Groundwater advisory; 

Weed resistant biotypes known; Do not 

spray if wind above 15 mph.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 578 of 946

Representative 

Brand

(EPA Reg. 

No.)

Active 

Ingredient

2010 use 

area 3

For a.i.

(K acres / 

%) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicat

ion)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special 

Directions

Weedar 64 (71368-

1)

2,4-D 

Dimethylami

ne Salt 

(DMA)

[see 2,4-D 

total above]

Danger 3.8 lb a.e./gal 48 hr 1.9 2 3.8 2 May be toxic to fish & aquatic invert; May 

result in groundwater contamination; Drift 

warning; Do not apply if wind above 15 

mph; Apply only when sensitive areas or 

plants are not with 250 feet downwind.

Reflex (100-993) Fomesafensodium1,415 / 3.1 Danger 2.0 lb a.e./gal 24hr 0.375 0.375 May leach; Groundwater advisory; Some 

long rotation intervals (up to 18 mos.); 

Cotton injury warning; Weed resistance 

advisory; State-specific limitations; Soil 

type limitations; 70-day cotton PHI

Gramoxone Inteon 

(100-1217)

Paraquat 1,078 / 2.3 Danger 2.0 lb 

cation/gal

12 hr 1 3 Restricted Use Pesticide due to acute 

toxicity; May be fatal if swallowed or 

inhaled; Toxic to wildlife; Damage / 

toxicity to non-target crops / plants; Drift 

advisory; Cotton injury possible; Do not 

feed treated foliage to livestock; 3-day 

cotton PHI.

Cotoran (66622-

181)

Fluometuron 786 / 1.8 Caution 4 lb/gal 24 hr 2 3 Known to leach; May result in 

groundwater contamination; Weed 

resistance advisory; Avoid drift to sensitive 

areas; 12-month rotation interval for many 

crops; State-specific limitations; Soil type 

limitations; Do not feed treated foliage to 

livestock; 60-day cotton PHI.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 579 of 946

Representative 

Brand

(EPA Reg. 

No.)

Active 

Ingredient

2010 use 

area 3

For a.i.

(K acres / 

%) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicat

ion)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special 

Directions

Caparol 4L (100-

620)

Prometryn 867 / 1.9 Caution 4 lb/gal 24 hr 2.4 6 Drift and runoff may be hazardous to 

aquatic organisms; 400 ft upwind swath 

adjustment for sensitive plants; Weed 

resistance advisory; Crop injury possible; 

Soil type limitations; State-specific 

limitations; Do not feed treated foliage to 

livestock.

Envoke (100-1132) Trifloxysulfur

on-sodium

423 / 0.9 Caution 0.75 lb / lb 12 0.012 0.019 Toxic to vascular plants; Ground water 

advisory; Weed resistance advisory; Long 

rotational intervals (12 -22 mos, some 

zones); 60-day cotton PHI; 25-foot buffer 

around treated areas recommended; State 

specific limitations; Soil type limitations.

Aim EW (279-

3242)

carfentrazone 

ethyl

89/0.16 Caution 1.9 lb/gal 12 hr 0.025 0.124 Carfentrazone-ethyl is very toxic to algae 

and moderately toxic to fish. Do not allow 

spray solution to contact cotton foliage, 

green stem tissue, or blooms.

Resolve DF (352-

556)

rimsulfuron 11/0.02 Caution granule 4 hr Not 

labeled 

for 

Cotton

0.03 Do not apply preemergence to coarse 

textured soils (sand, loamy sand, or sandy 

loam) with less than 1% organic matter. 

Adequate soil moisture is required for 

optimum activity. Long rotational 

restrictions up to 10 months. Crop injury 

may occur following application if there is 

prolonged cold weather and/or wet soils.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 580 of 946

Representative 

Brand

(EPA Reg. 

No.)

Active 

Ingredient

2010 use 

area 3

For a.i.

(K acres / 

%) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicat

ion)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special 

Directions

Treaty (71368-74) thifensulfuro

n methyl

81/0.15 Warning granule 12 hr 0.02 Pre-plant 

burn down 

in 

cotton

Causes substantial but temporary eye 

injury. Do not get in eyes or on clothing. 

Do not graze or feed forage or hay from 

treated areas to livestock. Weed control 

may be reduced if rainfall or snowfall 

occurs soon after application. 

Victory (71368-75) tribenuron 

methyl

70/0.13 Caution granule 12 hr 0.0125 Pre-plant 

burn down 

in 

cotton

Weed control in areas of thin crop stand or 

seedling skips may not be satisfactory. 

Weed control may be reduced if rainfall or 

snowfall occurs soon after application. Do 

not apply later than 14 days before planting 

cotton. Do not graze or feed associated by 

products for 60 days after application.

ET Herbicide 

(71711-7

Pyraflufen 

ethyl

56/0.1 Danger 0.208 lb/gal 12 hr 0.003 0.013 This pesticide is toxic to fish and aquatic 

invertebrates. Allow a minimum of 30 

days between applications for use on 

cotton. Apply to cotton having less than 3 

inches of stem bark using hooded ground 

equipment only. Avoid contact with 

desirable vegetation.

Goal 2XL (62719-

424)

oxyfluorfen 190/0.34 Warning 2 lb/gal 24 hr 0.5 1 This product is toxic to aquatic 

invertebrates and wildlife. Do not graze or 

harvest plants from treated areas for feed 

or forage. Treated soil must be thoroughly 

mixed to a depth of 4 inches after harvest 

prior to planting a rotational crop. Care 

must be taken to avoid spray contact with 

cotton leaves. Do not apply to cotton less 

than 6 inches tall or severe crop injury will 

result.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 581 of 946

Representative 

Brand

(EPA Reg. 

No.)

Active 

Ingredient

2010 use 

area 3

For a.i.

(K acres / 

%) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicat

ion)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special 

Directions

Resource (59639-

82)

flumiclorac 

pentyl ester

15/0.03 Warning 0.86 lb/gal 12 hr 0.05 0.094 Causes substantial but temporary eye 

injury. This product is toxic to shrimp. 

Keep out of lakes, ponds, and streams. Do 

not graze animals on green forage or use as 

feed fewer than 28 days after application.

1 Dicamba rates cited are those proposed for use on DGT cotton.

2 2,4-D products are not labeled for cotton treatments. Preplant treatments, more than 29 days before planting, are used for burndown weed control using the 

Fallow portion of the label. 

3 Monsanto private market survey data. The data shown are for the cotton acres to which the relevant active ingredient was applied in 2010, and the percentage

of total treated acres this constitutes. A treated acre is application of one active ingredient once. Multiple active ingredients or multiple applications results in 

total treated acres that exceed total planted cotton acres. No entry is shown for products containing more than one active ingredient, since these acres are 

counted in the single active ingredient rows.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 582 of 946

Table B-20. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide Products.

Active Ingredient First 

Registered

Registration 

Review

Status 1

RED 

Date

Max. Cotton 

lb/a (single 

application) 2

Max. Cotton 

lb/a (season) 2

Tolerances 

40 CFR 180.

Reduced 

Risk

Restricted Use

dicambadiglycolamine salt

2-Feb-56 unsched. 2006 1.03 2.03 227 N N

Glufosinateammonium

Glufosinateammonium

29-May-91 2008 N/A 0.79 1.59 473 Yes

Glyphosate (salts) Glyphosate 

(salts) 7-Sept-88 2009 09/23/2009 3.71 5.96 364 Yes

Herbicide a.i.s Applied Primarily at a PE Timing

2,4-D EHE (esters)4

3-Jun-52 2013 2005

2.0 5 4.0 5

142 N N

2,4-D DMA (salts)4

2.0 5 4.0 5

flumiclorac pentyl 23-Mar-94 2009 N/A 0.05 0.094 477 Yes No

S-metolachlor 18-May-83 2016 12/01/1994 1.27 2.48 368 Yes No

oxyfluorfen 17-May-79 2015 10/01/2002 0.5 1 381 No No

pyraflufen ethyl 27-Sept-02 2014 N/A 0.003 0.013 585 No No

rimsulfuron 20-Sept-89 2012 N/A Not labeled for 

cotton

0.03 478 No No

thifensulfuron methyl 25-Apr-86 2011 N/A 0.02 N/A 439 No No

tribenuron methyl 22-May-89 2011 N/A 0.0125 N/A 451 No No

Herbicide a.i.s Applied at both PE and POE Timings

carfentrazone ethyl 02-Aug-95 2011 N/A 0.025 0.124 515 Yes No

fluometuron 28-May-74 Unsched. 09/28/2005 229 No No

fomesafen sodium 10-Apr-87 2007 N/A 0.375 0.375 433 No No

paraquat dichloride 08-Jan-80 2011 08/01/1997 1 3 205 No Yes

Prometryn 19-Aug-74 2013 1996 2.4 5.95 222 N N

Pyrithiobac-Sodium 29-Jun-95 docket ‘11 NA 0.1 0.13 487 N N

Herbicide a.i.s Applied Primarily at a POE Timing

flumioxazin 01-Aug-96 2011 N/A 0.06 0.13 568 No No
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 583 of 946

MSMA 25-Dec-63 2013 2006 corr 

2009

1.88 3.75 289 N N

pendimethalin 20-Mar-75 2012 04/01/1997 2 2 361 No No

trifloxysulfuron-sodium 29-Jun-03 2013 NA 0.012 0.019 591 N N

trifluralin 04-Dec-68 2012 09/01/1995 2 2 207 No No

1 Registration Review Status: year docket is scheduled to open, unless unscheduled. FWP = Final Work Plan stage. If docket is open, “docket XX” = year opened.

2 Rates for dicamba, 2,4-D, fomesafen, and glyphosate are expressed as acid equivalents. All others are on an a.i. basis, as stated, except paraquat is on a cation basis. 

Regional or soil type limitations may lower this rate.

3 Maximum treatment rates for the proposed dicamba label on DGT cotton.

4 For the 2,4-D ester group, the ethylhexyl ester (EHE) is taken as representative. For the salt group, the dimethylamine (DMA) salt is taken as representative.

5 Rates taken from Master 2,4-D Label (http://www.24d.org/masterlabel/default.aspx) for Fallow application. There are no specific cotton treatment directions. Fallow 

application must precede planting by 29 days or more.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 584 of 946

Soil residual herbicides play an important role in cotton weed management by providing control of a 

number of weeds species that continuously germinate in cotton prior to canopy closure (Wilcut et al. 

2003). Soil residual herbicides, such as pendimethalin, trifluralin, diuron, fluometuron, acetochlor, 

and metolachlor, are applied to more than 40% of the current cotton acres (Monsanto 2012). In 

addition, many of the soil residual herbicides are limited by application restrictions, plant-back 

restrictions, the need for adequate soil moisture for activation, and the need to apply prior to 

planting or with hooded sprayers in-crop to minimize crop injury. Approximately 20% of growers 

applied a fall residual herbicide to control weeds prior to planting the following spring, and 60% 

(continuous cotton system) to 75% (GR cotton/GR soybean rotation) applied a mixture of 

glyphosate and a synthetic auxin herbicide (2,4-D or dicamba) as a spring burndown application 

(Prince et al. 2011a). Post emergent residual herbicides, such as metolachlor and acetochlor, were 

applied on over 25% of cotton acres in 2010 (Monsanto 2012). 

Further details on the use of non-glyphosate herbicides in cotton producing states can be found in 

Prince et al. (2011a; 2011b), where it is reported that approximately 50% of surveyed growers who 

did not have glyphosate-resistant weeds on their farm used a non-glyphosate residual and/or 

postemergence herbicide in the 2009 growing season. For growers who have on-farm herbicideresistant weed populations, the percentage of growers was higher, with 72% to 75% reporting the 

use of non-glyphosate herbicides. Older studies report that approximately 40 to 50% of the growers 

utilizing glyphosate-tolerant crops indicate that applying herbicides with different modes-of-action in 

sequence, rotating herbicides with different modes-of-action across the season, or tank mixing 

glyphosate with other herbicide modes-of-action are effective management practices to minimize the 

evolution and/or development of glyphosate resistance (Beckie 2006; Beckie and Reboud 2009; 

Diggle et al. 2003; Powles et al. 1996). The use of non-glyphosate herbicides in cotton production is 

expected to continue to increase as more growers adopt more diversified weed management 

strategies. 

B.3.4. Herbicide-resistant Weeds in Cotton Production

Glyphosate-resistant weed biotypes found in cotton fields in certain areas of the U.S. may include 

broadleaf biotypes of Palmer amaranth, waterhemp, common ragweed, giant ragweed, marestail, 

spiny amaranth (Amaranthus spinosus), and grass biotypes of ryegress, Johnsongrass (Sorghum halapense) 

and goosegrass (Elusine indica) (Heap 2012). The emergence and growth of herbicide-resistant 

weeds (including glyphosate-resistant weed biotypes) in certain areas of the U.S. over the past 

decade, has required growers to adapt and implement improved weed management strategies.

The occurrence of weed-resistant biotypes varies across the cotton-growing regions, with more 

resistance issues observed in certain areas of the Southeast and Midsouth cotton-growing regions. 

Table B-21 summarizes known resistance among the major weed species present in the southern 

U.S. for each of the key herbicide groups and herbicide classes that are efficacious on broadleaf 

weeds (Heap 2013a). Amaranthus spp., in particular Palmer amaranth, are problematic weeds in the 

mid-south and southeastern U.S. Palmer amaranth is considered to be one of the most competitive 

and aggressive of the Amaranthus spp. because of its rapid growth and prolific seed production. In 

addition, it has developed resistance to multiple herbicide classes (glycines, ALS, and dinitroanilines) 

(Culpepper et al 2011; Heap 2013b). Managing herbicide-resistant Palmer amaranth has proven to 

be challenging due to the biology of this particular weed, including its dioecious nature (the male and 

female flowers occur on separate plants), which leads to greater genetic diversity in the plant 

population and increases the potential for spreading herbicide resistance (Sosnoskie et al. 2011). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 585 of 946

Resistance to the ALS group of herbicides is present in most of the major broadleaf weed species 

commonly found in cotton. For Amaranthus spp. and Ambrosia spp., there is known resistance to at 

least one member for several of the major herbicide chemistry classes. In an effort to manage 

glyphosate-resistant Palmer amaranth in certain areas of the U.S., certain non-glyphosate cotton 

herbicides are being used in conditions and practices that can result in increased selection of 

resistant biotypes to those herbicides, and as a result some key agricultural herbicides in some major 

herbicide classes, such as glufosinate and PPO inhibitors, are at further risk (Nichols et al. 2010; 

Prostko 2011a; b) (Dr. Larry Steckel and Dr. Stanley Culpepper, personal communications, August 

2012). While there are effective options for managing Ambrosia spp., and Amaranthus spp., including 

Palmer amaranth and other key broadleaf weeds, the availability of additional herbicide modes-ofaction will help combat potential future resistance of the key herbicides needed for weed 

management in cotton. In addition, there has been an increase in the detection of weed populations 

with multiple resistances (i.e., resistance to multiple herbicide modes-of-action) in some weed 

species, for example, Amaranthus spp. (Tranel et al. 2010). The emergence of these resistant biotypes 

in certain areas of the U.S. highlights the continuing need to utilize diversified weed management 

practices and the ongoing need for additional herbicide modes-of-action that are effective in major 

crops. 

The relative occurrence of herbicide-resistant weeds varies between the different sub-groups of 

auxinic (phenoxy in Table B-21) herbicides. Considering that auxin herbicides have been widely 

used in agriculture for more than 60 years, weed resistance to this class is relatively low (29 species, 

to date, worldwide) and its development has been slow especially when compared to the speed of 

appearance of resistance to ALS inhibitors (107 species) or triazine-resistant populations (68 species) 

(Heap 2012b). The relatively low incidence of auxinic herbicide resistance is believed to be 

attributable to the fact that there are multiple target sites for these herbicides (Gressel and Segel 

1982; Morrison and Devine 1993).

Specific weed management recommendations by area or farm are made by local experts versed in 

the best methods for both proactive and reactive resistance management. Since more than 53.4% of 

cotton is repeatedly grown on the same land with only limited utilization of conservation tillage 

practices, the use of multiple herbicide modes-of-action with overlapping effectiveness on the 

targeted weed spectrum is the primary method recommended and employed for weed resistance 

management. Studies have shown that using the same combination of herbicides with multiple 

modes-of-action and overlapping effectiveness over multiple seasons can effectively manage 

resistance (Beckie and Reboud 2009). Monsanto and the weed scientist community recommend the 

use of multiple herbicide modes-of-action in herbicide-tolerant cotton systems regardless of whether 

glyphosate-resistant or hard-to-control broadleaf weeds are present (University of Georgia 2012; 

University of Tennessee 2012). APHIS has deregulated multiple herbicide-tolerant cotton traits 

(Table B-22), and the use of diversified weed management systems with these traits helps ensure 

sustained profitable cotton production across the Cotton Belt. For growers using the herbicidetolerant cotton systems, Monsanto and university extension weed scientists provide recommended 

control options for herbicide-resistant weeds110 (Bond et al. 2011; Culpepper et al. 2013; Ferrell et 

 

110 https://www.roundupreadyplus.com
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 586 of 946

al. 2012; Jordan et al 2011; Monsanto Company 2012; Norsworthy et al. 2012; Price et al 2011; 

Prostko 2011b; University of Tennessee 2012). These options include the use of residual and 

postemergence herbicides such as microtubule inhibitors (pendimethalin, trifluralin), PSII inhibitors 

(diuron, fluometuron, prometryn), PPO inhibitors (flumioxazin, fomesafen), long-chain fatty acid 

inhibitors (acetochlor, metolachlor), synthetic auxins (2,4-D, dicamba), and ALS inhibitors 

(pyrithiobac).111 These herbicides alone or in combinations, as well as traditional tillage methods, are 

and will continue to be used to control herbicide-resistant or hard-to-control broadleaf weeds.

 

111 Monsanto Technology Use Guide; www.weedresistancemanagement.com.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 587 of 946

1 Source: (Heap 2012), www.weedscience.org

2 Cross resistance is possible within a resistance group and/or chemistry class.

3 Includes redroot pigweed, smooth pigweed and common waterhemp.

Note: Blank boxes indicate no resistant biotypes for weed species/ herbicide combination in Southern U.S.

Table B-21. Known Weed Resistance in the Southern U.S. in 20121 

Resistance (Group) 2 

ALS 

(Group 2)

PPO 

(Group 14) 

PSI 

(Group 22) 

PS II 

(Group 5) 

PS II 

(Group 7) 

Organoarsenicals 

(Group 25) 

Microtubule 

Assembly 

Inhibitors 

(Group 3)

Glycine 

(Group 9) 

Phenoxy 

(Group 4) 

Chemistry Class 2 

sulfonylurea

diphenyl 

ether

N-phenyl 

thalimide bipyridiliums triazine ureas 

organoarsenicals dinitroaniline glycine phenoxy benzoic 

acid 

Cotton Herbicide Examples Trifloxysulfuron Fomesafen Flumioxazin Paraquat Prometryn Diuron 

Fluometuron MSMA Trifluralin Glyphosate 2,4 D Dicamba

Most Common Broadleaf Weeds in Southeast / Midsouth ( # of states listing as a top weed) 

morningglory (11) 

Ipomoea spp. 

prickly sida (9) 

Sida spinosa

pigweed spp. (6) 

Amaranthus spp.3 

X X X X X

Palmer amaranth (4) 

Amaranthus palmeri

X X X X

Florida Pusley (4) 

Richardia scabra 

sicklepod (4) 

Senna obtusifolia 

cocklebur (3) 

Xanthium strumarium

X X

horseweed (marestail) (3) Conyza 

canadensis

X X X X X

Ragweed spp. (2) 

Ambrosia spp. 

X X X X

Florida Beggarweed (2) 

Desmodium tortuosum
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 588 of 946

Table B-22. Deregulated Biotechnology-derived Cotton Products1

Phenotype Event Institution

Deregulation 

Effective Date 

Glufosinate tolerant, 

Lepidopteran resistant T303-3XGHB119 Bayer CropScience August, 2012

Glufosinate tolerant, 

Lepidopteran resistant

T304-40XGHB119 Bayer CropScience October, 2011

Lepidopteran resistant COT 67B Syngenta September, 2011

Glyphosate tolerant GHB614 Bayer CropScience May, 2009

Glyphosate tolerant MON 88913 Monsanto December, 2004

Lepidopteran resistant COT 102 Syngenta July, 2005

Lepidopteran resistant 281-24-236 Mycogen/Dow July, 2004

Lepidopteran resistant 3006-210-23 Mycogen/Dow July, 2004

Phosphinothricin tolerant2 LLCotton25 Aventis March, 2003

Lepidopteran resistant Cotton 15985 Monsanto November, 2002

Bromoxynil tolerant and 

lepidopteran resistant 31807 and 31808 Calgene April, 1997

Sulfonylurea tolerant 19-51a DuPont January, 1996

Glyphosate tolerant 1445, 1698 Monsanto July, 1995

Lepidopteran resistant 531, 757, 1076 Monsanto June, 1995

Bromoxynil tolerant BXN Calgene February, 1994

1 USDA-APHIS 2013.

2

 Glufosinate tolerant.

B.3.4.1. Sustainable Use of Dicamba as a Weed Management Option in Cotton

DGT cotton will be sold only in cotton varieties that also contain other herbicide-tolerant 

traits, including glyphosate-tolerance. Cotton varieties containing both DGT cotton and a 

glyphosate-tolerant system will enable dicamba and glufosinate to be applied with glyphosate 

and/or other cotton herbicides in an diversified weed management program. Dicamba 

primarily will be used in mixtures with either glyphosate or glufosinate or in sequence with 

glyphosate or glufosinate to control a broad spectrum of grass and broadleaf weed species. 

Glyphosate and glufosinate will not be used in mixtures due to antagonism (i.e., glufosinate 

damages the leaf tissue before glyphosate gets into the plant and/or can be translocated to 

growing parts of the plant) that reduces the efficacy of glyphosate on susceptible weed 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 589 of 946

species. Dicamba and glufosinate applications on DGT cotton will provide effective control 

of glyphosate-resistant broadleaf weeds and improve the control of annual and perennial 

broadleaf weed species, some of which are difficult to control with glyphosate. Dicamba and 

glufosinate will also help mitigate the potential for the evolution and development of and/or 

combat existing weed resistance issues that can limit the use of the PPO- and ALS-inhibiting 

herbicide groups by providing additional modes-of-action for management of certain 

broadleaf species known to be prone to resistance to many of the current herbicide options 

for weed management (i.e., Amarathus spp.). Likewise, dicamba will help to mediate potential 

evolution of resistance to glufosinate in broadleaf species and glufosinate will do the same 

for the potential evolution of resistant broadleaf species to dicamba. Cultivation of a 

combined DGT cotton and glyphosate-tolerance trait product will foster the adoption of 

Integrated Pest Management (IPM) practices in cotton by allowing growers to continue to 

primarily focus on postemergence in-crop weed control, as they have practiced with the 

glyphosate-tolerant cotton systems. This will allow growers to delay some herbicide 

treatments until field scouting indicates a need for additional postemergence weed control 

which is consistent with the principles of IPM, and also herbicide resistance management 

practices. Increasing postemergence herbicide options in cotton is important, especially in 

conservation tillage situations, where consistency of postemergence herbicides has generally 

been greater than that of soil active residual products, which have greater degree of 

inconsistent weed control, and thus has been a factor in the adoption of conservation tillage 

systems in the U.S.

Upon the integration of DGT cotton into the glyphosate-tolerant cotton systems and 

proposed approval of the use of dicamba on DGT cotton by the U.S. EPA, 

preplant/preemergence applications of dicamba can be made up to 1.0 lb a.e./acre up 

through crop emergence (cracking) and in-crop postemergence applications up to 0.5 lb 

a.e./acre could be applied through 7 days preharvest, with the combined total not to exceed 

2.0 lbs a.e. dicamba per year for all applications. Residual herbicides also will be 

recommended for use, to provide early season weed control and to supplement dicamba and 

glufosinate activity on certain hard-to-control and glyphosate-resistant weed biotypes, such 

as glyphosate-resistant Palmer amaranth where weed populations can be very substantial. 

Dicamba and glufosinate, as complementary herbicides to glyphosate, will provide new weed 

control options in cotton that strengthen the utility and sustainability of glyphosate as a weed 

control tool for the combined DGT cotton glyphosate-tolerance trait product. 

In the event that there is known or suspected presence of a dicamba-resistant or glufosinateresistant weed biotype, other options for managing the resistant biotypes are available to the 

grower. There are multiple preemergence (including soil residuals) and postemergent 

herbicide options for managing weed populations that are resistant or may potentially 

develop resistance to dicamba or glufosinate in cotton, as well for crops grown in rotation 

with cotton. These options are noted in Table B-23. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 590 of 946

Table B-23. Management Recommendations for Control of Dicamba-, Glufosinateand Other Selected Synthetic Auxin-Resistant Weeds

Rotational Crops

Weed 

Species 1

Herbicide 

Resistant 

Biotypes

Primary 

Crop 

Cotton

Corn Sorghum Soybeans Wheat

Kochia dicamba, 

fluroxpyr 

(populations 

also resistant 

to glyphosate)

Clomazonea

Flumioxazini

Glyphosatei

Paraquati

Atrazinea

Saflufenacila

Isoxaflutolea

Mesotrionea

Glyphosatea

Atrazinea

Saflufenacila

Isoxaflutolea

Mesotrionea

Glyphosatea

Saflufenacila

Clomazonea

Flumioxazina

Glyphosatea

Paraquata

Saflufenacila

Glyphosatea

Bromoxynil/MCP

Aa

Prickly 

Lettuce

Dicamba, 2,4 

D, MCPA

Glyphosatei

Paraquati

Flumioxazini

Saflufenacila

Atrazinea

Carfentrazone

+ atrazinea

Isoxaflutole +

atrazinea

Saflufenacila

Atrazinea

Carfentrazone

+ atrazinea

Isoxaflutole +

atrazinea

Saflufenacila

Chlorimuron/

metribuzinc

Glyphosate +

imazethapyra

Saflufenacila

Triasulfurona

Metsulfuron +

thifensulfuronaa

Wild 

mustard

Dicamba , 2,4

D,MCPA, 

picloram,

dichlorprop,

mecoprop

Glyphosatei

Paraquati

Glyphosateic

Atrazinec

Primisulfuronc

Nicosulfurond

Halosulfurond

Glyphosateic

Atrazinec

Primisulfuronc

Nicosulfurond

Halosulfurond

Glyphosatec

Chlorimuronc

Chlorimuron/

metribuzinc

Field

Bindweed

2,4 D Glyphosatei

Paraquati

Flumioxazini

Glyphosatea

Glyphosate +

imazethapyra

Glyphosate +

Imazamoxa

Glyphosatea

Glyphosate +

imazethapyra

Glyphosate +

Imazamoxa

Glyphosatec Glyphosatea

Yellow 

Starthistlee

Picloram
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 591 of 946

Table B-23 (continued). Management Recommendations for Control of Dicamba-, 

Glufosinate- and Other Selected Synthetic Auxin- Resistant Weeds 

Rotational Crops

Weed 

Species1

Herbicide 

Resitant 

Biotypes

Primary 

Crop Cotton

Corn Sorghum Soybeans Wheat

Spreading

Dayflower

2,4 D Bentazon 

halosulfuron 

penoxsulam 

bispyribacf

Lambsquarters

g

Dicamba Paraquati

Flumioxazini

Glyphosateb

Isoxaflutolea

Atrazinea

Saflufenacila

Mesotrionea

Bromoxynilb

Metribuzinb

Cloransulamb

Saflufenacila

Imazamoxb

Glyphosateb

Bromoxynila

Chlorsulfuron

/

Metsulfurona

Glyphosateh

Saflufenacila

Goosegrass Glufosinate Clethodimh

Glyphosateh

pendimethalin

h

trifluralinh

Glyphosateh

pendimethalin

h

Glyphosateh Clethodimh

Glyphosateh

pendimethalin

h

trifluralin

Glyphosateh

Italian ryegrass Glufosinate

(population

s also 

resistant to 

glyphosate)

Metolachlor 

(fall applied)h

Clethodimh

Glyphosateh

Paraquati

Metolachlor 

(fall applied)h

Glyphosateh

Metolachlor 

(fall applied)h

Glyphosateh

Metolachlor 

(fall applied)h

Clethodimh

Glyphosate

h

Glyphosateh

Waterhemp 2,4 Dj Fomesafenk

Fluometuronk

Metolachlork

Diuronk

Flumioxazink

Metolachlorl

Atrazinel

Saflufenacill

Mesotrionel

Carfentrazone

l

Metolachlorm

Fluroxypyrm

Atrazinem

Saflufenacilm

Carfentrazone

m

Metolachlorl

Flumioxazinl

Sulfentrazone 

+ metribuzinl

Fomesafenl

Acifluorfenl

Metsulfuronn

Triasulfuronn

Prosulfuronn

Fluroxypry+ 

bromoxyniln

1Scientific names for each weed species can be found in Table VIII-4 of the DGT coybean Petition for Deregulation.

aBernards et al., 2010.

bLoux et al., 2010.

cMSU, 2010.

dKells and Stachler, 1997.

ePNWE, 2010.

fUniversity of Arkansas CES, 2010.

gResistance to lambsquarters has only been confirmed in New Zealand.

hSteckel et al., 2011

iSmith et al., 2012

jBernards et al., 2012.

kMississippi State University, 2013

lLoux et al., 2013

mUniversity of Missouri,2013

nUniversity of Nebraska, 2013
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 592 of 946

B.3.4.2. Stewardship of Dicamba Use on DGT Cotton

In order to steward the use of agricultural herbicides and herbicide-tolerant cropping 

systems such as the combined trait DGT cotton and glyphosate-tolerant cotton product, 

Monsanto has conducted investigations and worked extensively with academics and other 

herbicide manufacturers to understand and recommend best practices to manage herbicide 

resistance. These investigations have demonstrated that one of the major factors 

contributing to the development of resistant weed biotypes in certain areas of the U.S. has 

been inadequate weed control management practices. The primary reasons for lack of 

adequate management includes: 1) application of herbicides at rates below those indicated on 

the product label for the weed species, and 2) sole reliance on a particular herbicide for weed 

control without the use of other herbicides or cultural control methods (Beckie, 2006; 

Peterson et al., 2007). 

B.3.4.3. Weed Control Recommendations

The proposed label for dicamba use on DGT cotton – which is currently pending before 

EPA - is based on the maximum allowable use rates and patterns. Prior to launch of DGT 

cotton in glyphosate-tolerant cotton systems, Monsanto, in cooperation with academics, will 

conduct trials to confirm the optimum rate and timing for dicamba, glufosinate and 

glyphosate, alone and in combination, and other herbicides. Recommendations to growers 

will be developed from this information and will be provided in herbicide product labels, 

Monsanto’s Technology Use Guide (TUG), and in other education and training materials to 

be broadly distributed. Specifically, current research conducted by Monsanto to define the 

optimum weed management systems support use recommendations that include the 

application of dicamba and glyphosate for preemergence on conservation tillage acres and 

early postemergence in-crop applications. In some situations, a second in-crop application of 

either dicamba tank-mixed with glyphosate or glufosinate, with or without a soil residual will 

be recommended (see Section VIII.G.4 for additional details) 

These recommendations will ensure more than one mechanism of action against the targeted 

species, which is a fundamental component of a good weed resistance management 

program. These management systems, which include the use of multiple effective herbicide 

modes-of-action, will reduce the potential for further resistance development to glyphosate, 

dicamba, and glufosinate, as well as other critical cotton herbicides. Furthermore, the 

preplant weed spectrum is generally different from the in crop weed spectrum; therefore, 

multiple applications of glyphosate and dicamba are not expected to increase selection 

pressure on either herbicide.

B.3.4.4. Dispersal of Technical and Stewardship Information

To support the introduction of varieties containing DGT cotton, Monsanto will use multiple 

methods to distribute technical and stewardship information to growers, academics and 

grower advisors regarding the use of the product as part of a diversified weed management 

system. Growers who purchase Monsanto varieties containing DGT cotton sign a limited 

use license known as the Monsanto Technology Stewardship Agreement (MTSA). The 

MTSA obligates growers to comply with certain requirements, including the Monsanto 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 593 of 946

Technology Use Guide (TUG). The TUG will set forth the requirements and best practices 

for the cultivation of DGT cotton including recommendations on weed resistance 

management practices. 

The weed resistance management practices that will be articulated in the TUG will also be 

broadly communicated to growers and retailers in order to minimize the potential for the 

development of resistant weeds. These practices will be communicated through a variety of 

means, including direct mailings to each grower purchasing a cotton variety containing DGT 

cotton, a public website, and reports in farm media publications. The overall weed resistance 

management program will be reinforced through collaborations with U.S. academics, who 

will provide their recommendations for appropriate stewardship of dicamba and glufosinate 

in cotton production, as well as by collaboration with crop commodity groups who have 

launched web-based weed resistance educational modules. Finally, Monsanto will urge 

growers to report any incidence of repeated nonperformance of dicamba or glufosinate on 

weeds in fields planted with DGT cotton, and Monsanto will investigate cases of 

unsatisfactory weed control to determine the cause as discussed below in Section B.4.4.6. 

EPA regulates under FIFRA the pesticides (including herbicides) that are used with crops, 

including GE herbicide-tolerant crops like DT soybean and DGT cotton. FIFRA requires 

all pesticides to be registered before distribution or sale, unless they are exempted. Under 

FIFRA, EPA must approve each distinct pesticide product, each distinct use pattern, and 

each distinct use site. Each crop for example, consititues a unique use site and no registered 

pesticide may be applied to any crop unless EPA has approved that specific pesticide/crop 

use.

EPA encourages pesticide manufacturers to provide growers with information regarding an 

herbicide’s mode-of-action to aid growers in planning herbicide use practices and to foster 

the adoption of effective weed resistance management practices as specified by EPA in 

Pesticide Registration (PR) Notice 2001-5 (U.S. EPA, 2001). In that document, EPA states 

that “this approach to resistance management is sound and would be highly beneficial to 

pesticide manufacturers and pesticide users.” It is a violation of FIFRA to use any registered 

pesticide in a manner inconsistent with its labeling, subject to criminal and civil penalty. 112 

For that reason, an approved herbicide cannot be lawfully used on a corresponding 

herbicide-tolerant crop, unless EPA approves a label amendment for such use.

In summary, Monsanto will require weed resistance management practices through the 

MTSA and TUG for its biotechnology-derived herbicide-tolerant products, such as DGT 

cotton integrated into the glyphosate-tolerant cotton systems, and to promote these practices 

through product labeling and educational outreach efforts as an effective means to mitigate 

the potential for weed resistance development for dicamba, glufosinate, and glyphosate. 

 

112 FIFRA §12(a)(2)(G) and §14
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 594 of 946

B.3.4.5. Weed Resistance Management Practices

Monsanto will provide information to growers and grower advisors on best management 

practices to mitigate the potential for evolution and development of resistance to dicamba 

and glufosinate. The weed resistance management recommendations for the use of dicamba 

and glufosinate in conjunction with cotton varieties containing DGT cotton will be 

consistent with the Herbicide Resistance Action Committee’s guidelines for prevention and 

management of herbicide resistance (HRAC, 2010). These guidelines recommend an 

diversified approach to weed resistance management, including crop management (i.e., cover 

crops, crop rotation, etc.), cultivation techniques, and the use of multiple herbicide modesof-action to manage a weed population. 

In cases where resistance is confirmed for dicamba or glufosinate in cotton producing areas, 

Monsanto and university/Cooperative Extension Service (CES) personnel will provide 

recommendations for alternative herbicide control methods to growers. These 

recommendations would be made available through Monsanto supplemental labels, 

Monsanto and university publications, and internet sites to growers, consultants, retailers and 

distributors. For all existing cases of dicamba-resistant and glufosinate-resistant weeds in the 

U.S. and globally today, alternative herbicides and cultural methods are available to growers 

to effectively control these biotypes. Examples of recommended alternative herbicides from 

university/CES personnel that are applicable to weed species known to be resistant to 

glufosinate, dicamba and other synthetic auxin herbicides are found in Table B-23. However, 

these examples in Table B-24 are only a subset of product combinations of available cotton 

herbicides.

B.3.4.6. Monsanto Weed Performance Evaluation and Weed Resistance 

Management Plan

An important part of a weed resistance management plan is the timely acquisition of 

information regarding product performance. Monsanto has an extensive technical, sales and 

marketing presence in the cotton markets where DGT cotton will be grown. Through our 

relationships with farm advisors, key university/CES personnel, and growers using our seeds 

and traits products, Monsanto will acquire important and timely information regarding 

product performance. This will allow the timely recognition of performance issues that could 

arise related to weed resistance or other means. Field employees and hired consultants are 

trained and provided processes for responding to product performance inquiries. Individual 

performance issues that could be related to potential resistance are promptly handled. In 

addition, performance inquiries are periodically reviewed by Monsanto for trends that could 

indicate the need for follow up action on a broad scale. 

If dicamba or glufosinate resistance is confirmed, the scientific and grower communities will 

be notified and a weed resistance mitigation plan will be implemented by Monsanto in 

cooperation with the university/CES and/or the appropriate herbicide producer . The 

mitigation plan will be designed to manage the resistant biotype through effective and 

economical weed management recommendations implemented by the grower. The scope 

and level of intensity of the mitigation plan may vary depending on a combination of the 

following factors: 1) biology and field characteristics of the weed (seed shed, seed dormancy, 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 595 of 946

etc.), 2) importance of the weed in the agricultural system, 3) resistance status of the weed to 

other herbicides with alternate modes-of-action, and 4) availability of alternative control 

options. These factors are analyzed by Monsanto and university/CES personnel in 

combination with economic and practical management considerations to develop a tailored 

mitigation strategy. The plan considers what is technically appropriate for the particular weed 

and incorporates practical management strategies that can be implemented by the grower.

After a mitigation plan is developed, Monsanto communicates the plan to the grower 

community through the use of supplemental herbicide labeling (labeling which includes 

newly approved use directions, or other instructions), informational fact sheets, retailer 

training programs, agriculture media and/or other means, as appropriate. 

In addition to the grower inquiry-initiated process, Monsanto, alone and/or in cooperation 

with university/CES, will conduct field studies to understand the potential for weed 

resistance and weed shifts as the result of various weed management programs implemented 

for DGT cotton integrated into glyphosate-tolerant cotton systems. These studies will allow 

researchers to better track specific factors that can influence the development of resistance 

to specific weeds.

B.3.5. Benefits of DGT Cotton Production

B.3.5.1. Overview

DGT cotton will provide additional weed management options for effective and sustainable 

weed management in cotton production. DGT cotton will be combined with glyphosatetolerant cotton utilizing traditional breeding techniques. This combination of herbicidetolerance traits will allow growers to use dicamba, glufosinate and glyphosate herbicides in a 

diversified weed management program to control a broad spectrum of grass and broadleaf 

weed species. DGT cotton will contribute additional benefits and value to the wellestablished and effective glyphosate-tolerant weed control systems in cotton. Glyphosate 

provides excellent control of many annual and perennial grass and broadleaf weed species. 

Dicamba provides effective control of many summer and winter annual broadleaf weed 

species and will be very complementary to glyphosate by offering improved control of hardto-control broadleaf weed species in cotton, including Florida pusley, hemp sesbania, 

lambsquarters, morningglory species, prickly sida, purslane, and Pennsylvania smartweed. 

Glufosinate will offer improved control of certain broadleaf weeds, including lambsquarters 

and morning glory species as compared to glyphosate. Dicamba and glufosinate will also 

offer effective control options for glyphosate-resistant broadleaf weed biotypes in certain 

areas of the U.S., including glyphosate-resistant biotypes of Palmer amaranth, horseweed, 

and common ragweed. Additionally, dicamba and glufosinate will offer an effective control 

option for broadleaf species resistant to other herbicide classes (e.g., ALS and PPO 

chemistries). DGT cotton will provide growers expanded use of dicamba in cotton 

production by enabling preemergence applications of dicamba at rates up to 1.0 lb a.e. per 

acre up to the day of crop emergence and postemergence in-crop applications up to 0.5 lbs. 

a.e. per acre per application up through seven days prior to harvest. Additionally, like 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 596 of 946

commercially available glufosinate-tolerant cotton, DGT cotton enables application of up to 

0.53 lb a.i. per acre per application of glufosinate from emergence through early bloom 

growth stage. 

Beginning in 2010, numerous field experiments have been conducted by university weed 

control specialists and Monsanto researchers in the Southeastern and Midsouth regions of 

the U.S. and Texas to evaluate the efficacy of weed control programs in dicamba, 

glufosinate, and glyphosate-tolerant cotton. These studies evaluated the control of 

glyphosate-resistant and hard-to-control weeds with the primary focus on the control of 

glyphosate-resistant Palmer amaranth. Dicamba, glufosinate, and tank mixtures of dicamba 

plus glyphosate or glufosinate were evaluated in weed control programs involving 

preemergence residual herbicides on the stacked trait cotton product. These experiments 

provided valuable data for determining the best recommendations and weed management 

systems for optimum control of weeds in various climatic conditions and cotton production 

systems across the various cotton regions of the U.S. 

The expected use patterns for dicamba and glufosinate on DGT cotton will vary across U.S. 

cotton growing regions. This variability is dictated by the environment, weed spectrum and 

tillage options. In general cotton acres are expected to receive one or two in-crop application 

of dicamba regardless of tillage. Conservation tillage or no-tillage acres are expected to 

receive an additional preplant application of dicamba. One application of glufosinate is 

recommended in the MidSouth and Southeast where glyphosate-resistant weeds are present, 

regardless of tillage. In addition, glyphosate and soil residuals will be included in the 

recommended weed management programs for DGT cotton.

Monsanto and university weed control specialists recommend and encourage the use of 

preemergence and/or postemergence applications of soil residuals, along with postemergent 

products, as part of a comprehensive weed resistance management program. This ensures 

that two or more effective herbicide modes-of-action are used to provide protection against 

additional resistance development to existing cotton herbicides (Bullington et al., 2011; 

Culpepper et al., 2011; Steckel et al., 2012). Preemergence soil residuals also provide earlyseason weed control to reduce early weed competition to protect yield potential and provide 

greater flexibility in timing of postemergence applications. In addition, preemergence 

residuals will assist in the control of grasses and certain hard-to-control weed species. The 

addition of soil residual herbicides is an effective component of a program for optimum 

weed control and long-term sustainability of cotton weed control products. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 597 of 946

Table B-24. Anticipated Weed Management Recommendations for DGT Cotton 

Combined with Glyphosate-Tolerant Cotton Systems for MO, AR, TN, AL, FL, GA, 

NC, SC, VA, LA, MS, eastern TXand CA.1,2

Application Timing Conventional Tillage Conservation Tillage 

(No-till or reduced till)

Preplant burndown 

and/or Preemergence Residual Dicamba + Glyphosate + Residual

Postemergence 1 Dicamba + Glyphosate + 

Residual3 Dicamba + Glyphosate + Residual

Postemergence 2 Glyphosate OR 

Glufosinate4,5

Glyphosate OR Glufosinate + 

Residual5,6

1 Recommendations modified from those presented in Petition 12-185-01p_a1.

2 Monsanto and academics recommend the use of soil residuals as part of a comprehensive weed resistance 

management program to ensure that two effective herbicide modes-of-action are used in cotton and to provide 

protections against additional resistance development to existing cotton herbicides.

3 Residual recommended if GR weeds present.

4 Glyphosate recommended if no GR weeds present, glufosinate recommended in the presence of GR weeds.

5Tank mixes of glyphosate and glufosinate will not be recommended, because reduced weed control has been 

observed with the glyphosate and glufosinate tank mix as compared to each individual herbicide (Dotray et al. 

2011; Reed et al. 2011; Reed et al. 2012).

6 Glyphosate only if no GR weeds present, glufosinate and residual recommended in the presence of GR 

weeds.

Table B-25. Anticipated Weed Management Recommendations for DGT Cotton 

Combined with Glyphosate-Tolerant Cotton Systems for western TX, NM, KS, OK, 

and AZ 1,2

Application Timing Conventional Tillage Conservation Tillage 

(No-till or reduced till)

Preplant burndown and/or 

Preemergence 

Dicamba + Glyphosate + 

Residual

Dicamba + Glyphosate + 

Residual

Postemergence 1 Dicamba + Glyphosate Dicamba + Glyphosate 

Postemergence 2 Glyphosate ± Dicamba3 Glyphosate ± Dicamba3

1 Recommendations modified from those presented in Petition 12-185-01p_a1.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 598 of 946

2 Monsanto and academics recommend the use of soil residuals as part of a comprehensive weed resistance 

management program to ensure that two effective herbicide modes-of-action are used in cotton and to provide 

protections against additional resistance development to existing cotton herbicides.

3 Dicamba recommended when GR weeds present.

B.3.5.2. Benefits of the Weed Management System of Dicamba, Glufosinate, and 

Glyphosate-Tolerant Cotton

Extensive research by both university weed control specialists and Monsanto researchers in 

2010 and 2011 demonstrates that growers will realize several benefits from utilizing the 

proposed weed management systems of dicamba, glufosinate, and glyphosate-tolerant 

cotton. These benefits include: 

 Effective and sustainable management of glyphosate-resistant weed species;

 Improved and more consistent control of hard-to-control broadleaf weed species;

 Crop safety to dicamba, glufosinate, and glyphosate herbicides to maximize cotton 

lint yield potential;

 Application flexibility in the event of challenging weather conditions especially in the 

spring;

 Proactive program for weed resistance management; and 

 Preservation of conservation tillage benefits. 

Each benefit attribute is described and discussed below to substantiate the benefit in greater 

detail.

B.3.5.2.1. Effective and Sustainable Management of Glyphosate Resistant Weed 

Species

Glyphosate has been used extensively in agricultural production systems since being 

commercially introduced in 1974. Roundup Ready cotton was commercially introduced in 

1997, further expanding the use of glyphosate in cotton. In 2006, a second generation 

glyphosate-tolerant product (Roundup Ready Flex cotton) was introduced that provided 

increased tolerance to glyphosate in the reproductive stages of cotton and allowed for an 

expanded window for over-the-top applications of glyphosate in cotton. In 2012, 

glyphosate-tolerant cotton represented 80% of all upland cotton acres planted in the U.S., up 

from 73% in 2011 (USDA-NASS, 2012). Due to the broad-spectrum activity of glyphosate, 

it has been possible for growers to rely predominately on glyphosate for weed management 

and not utilize diversified weed management practices such as crop rotation, mechanical 

cultivation or the use of multiple herbicide modes-of-action. Reliance on glyphosate in 

glyphosate-tolerant crops for total weed management in the absence of other herbicides and 

weed control management practices has contributed to the selection of weed populations 

that are resistant to this herbicide in certain areas of the U.S. Currently, there are 13 weed 

species (6 grasses and 7 broadleaf species) that are resistant to glyphosate in the U.S (Heap, 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 599 of 946

2012). Populations of the following four broadleaf weed species are resistant to glyphosate 

and are agronomically important weeds in cotton: Palmer amaranth, common waterhemp, 

horseweed, and common ragweed. Glyphosate-resistant Palmer amaranth may occur in up 

to 50% of the U.S. upland cotton acres according to some estimates (Sosnoskie and 

Culpepper, 2012). 

University weed control specialists and Monsanto researchers have extensively evaluated the 

effectiveness of dicamba and glufosinate for control of several of these glyphosate-resistant 

weeds. Studies conducted in dicamba, glufosinate, and glyphosate-tolerant cotton were 

beneficial in determining the efficacy of dicamba and glufosinate applied preemergence and 

postemergence for glyphosate-resistant Palmer amaranth control. Studies with dicamba, 

glufosinate, and glyphosate-tolerant cotton were initiated in 2011 and were focused almost 

entirely on evaluating the efficacy of various weed management systems utilizing dicamba, 

glufosinate, and glyphosate with and without residual herbicides for control of glyphosateresistant Palmer amaranth. 

B.3.5.2.1.1. Glyphosate-Resistant Palmer Amaranth

Palmer amaranth is a summer annual broadleaf that is a problematic weed in the mid-south 

and southeastern U.S. (Morichetti et al., 2012). It is considered to be one of the most 

competitive and aggressive of the pigweed species because of its rapid growth and prolific 

seed production. Palmer amaranth is also dioecious (the male and female flowers occur on 

separate plants) which leads to greater genetic diversity in the plant population and increases 

the potential for spreading herbicide resistance. Since the development of glyphosateresistant Palmer amaranth in the southeast, herbicide use patterns have changed, increasing 

the herbicide costs to $60 to $70 per acre in heavily infested areas (Sosnoskie and Culpepper, 

2012). In addition, growers have increased the use of hand-weeding and in-crop cultivation 

to manage the high populations of glyphosate-resistant Palmer amaranth. Georgia growers 

indicate that up to 50 to 60% of their cotton acres are currently hand-weeded at a cost of 

$23 per acre (Sosnoskie and Culpepper, 2012). Prior to the development of glyphosateresistant Palmer amaranth (2005), 17% or less of Georgia cotton acres were hand-weeded. 

According to Georgia growers, 44% of the cotton acres are subjected to in-crop mechanical 

cultivation in 2010/2011 (Sosnoskie and Culpepper, 2012). 

Studies conducted on glyphosate-resistant Palmer amaranth support the importance of 

making dicamba applications early in the season to small weeds (4 inches or less in height) 

and applying dicamba at a rate of 0.5 lbs. a.e./acre for effective control. Studies showed the 

most consistent control with a dicamba rate of 0.5 lbs. a.e./acre. Diversified weed 

management programs consisting of a residual preemergence herbicide followed by one or 

two sequential postemergence applications of glyphosate plus dicamba or a total post 

program consisting of two sequential postemergence applications of glyphosate plus 

dicamba provide excellent control of glyphosate-resistant Palmer amaranth. 

 Field trials conducted across the cotton belt in 2010 and 2011 on glyphosate-susceptible 

and resistant Palmer amaranth showed that both dicamba and glufosinate are effective 

on Palmer amaranth when applications are made to weeds less than four inches in height 

(Voth et al., 2012). However, efficacy is reduced as the weeds increase in size, especially 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 600 of 946

when greater than 6-8 inches in height. The tank mixtures of dicamba plus glufosinate 

provided better control than either product applied alone.

 Field trials were conducted at five locations in 2011 to compare the efficacy of dicamba 

and glufosinate applied alone, as tank mixtures, or in sequence for control of tall (8 and 

16 inches) glyphosate-resistant Palmer amaranth plants (Bollman et al., 2012). The 

general recommended timing for best control of Palmer amaranth for these products is 

to apply to plants less than 4 inches. Palmer control was greater with dicamba and 

glufosinate when applications were made to 8-inch plants compared to 16-inch plants 

regardless of whether applied alone, tank mixed or applied in sequence. Tank mixtures 

and sequential applications of dicamba and glufosinate improved control over either 

product used alone in these studies. 

 Studies conducted by Mississippi State University show that glyphosate-resistant Palmer 

amaranth control is improved with single applications of dicamba when the rates are 

increased from 0.25 to 0.5 lbs. a.e./acre (50 - 63% vs. 66 – 68%) (Samples et al., 2012). 

Single applications of glufosinate at 0.53 lbs. a.i./acre provided similar control at 56 -

74%. Sequential applications of dicamba (0.5 lbs. a.e./acre) and glufosinate (0.53 lbs. 

a.i./acre) are required for adequate control of Palmer amaranth. Where sequential 

applications of these herbicides are utilized, the best results were obtained when dicamba 

was applied first followed by glufosinate.

 Field trials were conducted at three locations in 2011 to evaluate the efficacy of several 

weed control programs in dicamba, glufosinate, and glyphosate-tolerant cotton on 

control of glyphosate-resistant Palmer amaranth (Bollman et al., 2012). These programs 

included various preemergence (PRE) herbicide treatments followed by various early 

post (EPOST) treatments. All programs received one late post (LPOST) application of 

glufosinate plus acetochlor. Including a PRE treatment of fomesafen, dicamba (0.5 lbs 

a.e./acre) or a tank mixture of fomesafen plus dicamba (0.5 lbs a.e./acre) significantly 

improved Palmer control (>92% control) compared to programs with no PRE treatment 

regardless of the EPOST treatment (15-85% control). Programs with fomesafen plus 

dicamba applied PRE provided the most consistent Palmer control (>95%). Glyphosate 

plus dicamba (0.5 lbs a.e./acre), glyphosate plus dicamba (0.5 lbs a.e./acre) plus 

acetochlor, and glufosinate (0.53 lbs a.i./acre) plus dicamba (0.5 lbs a.e./acre) were 

effective EPOST treatments with the inclusion of a PRE herbicide treatment in the 

program. The addition of acetochlor EPOST to the tank mixture of glyphosate plus 

dicamba improved control slightly. Glufosinate plus acetochlor EPOST provided 

unsatisfactory control when following dicamba PRE.

 Field studies were conducted in five Midsouth and Southeastern states in 2011 on 

glyphosate-resistant Palmer amaranth (Dodd et al., 2012). Control of glyphosateresistant Palmer amaranth from EPOST applications to 2- to 4-inch plants was less than 

55% with glyphosate alone while EPOST applications of dicamba (0.5 lbs. a.e./acre) 

alone provided 86% control. Fourteen weed management programs were evaluated that 

included glyphosate, glufosinate and dicamba applied at various application timings. All 

the program treatments also received a LAYBY application of diuron plus MSMA. The 
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total POST programs that provided greater than 97% control were glyphosate or 

glufosinate tank mixed with dicamba (0.5 lbs. a.e./acre) EPOST to 2- to 4-inch plants 

followed by glufosinate (0.53 lbs. a.i./acre) MIDPOST to 10- to 18-inch plants. The 

PRE/POST programs that provide >97% control were dicamba (0.5 lbs. a.e./acre) PRE 

followed by EPOST application of glufosinate (0.53 lbs. a.i./acre) alone, glufosinate 

(0.53 lbs. a.i./acre) or glyphosate plus dicamba (0.5 lbs. a.e./acre) followed by 

MIDPOST application of glufosinate (0.53 lbs. a.i./acre) or glyphosate plus dicamba (0.5 

lbs. a.e./acre). Programs with lesser post applications such as dicamba PRE followed by 

EPOST application of glufosinate alone or glufosinate or glyphosate tank mixed with 

dicamba provided 83 – 93% control. The researchers concluded that season-long 

control (greater than 90%) was achieved with various PRE/POST programs utilizing 

dicamba, glyphosate, and glufosinate when applied in timely manner (weeds less than 4 

inches in height). However, residual herbicides should continue to be an integral part of 

a total weed management program.

 Trials were conducted in NC and GA in 2010 and 2011 on a site infested entirely with 

glyphosate-resistant Palmer amaranth and a site with both glyphosate-resistant and –

susceptible Palmer amaranth to evaluate several weed management programs utilizing 

residual herbicides and the addition of dicamba and glufosinate (York et al., 2012). The 

glyphosate only program failed to provide adequate control of glyphosate-resistant 

Palmer amaranth. Excellent control was achieved with dicamba (0.5 lbs. a.e./acre) PRE 

followed by glyphosate plus dicamba EPOST and MPOST. Glufosinate (0.5 lbs. 

a.i./acre) EPOST or LPOST followed by diuron +MSMA lay-by provided 80 to 97% 

control of glyphosate-resistant Palmer amaranth depending on the location and year. 

The addition of dicamba (0.5 lbs. a.e./acre) either as a PRE or POST application to a 

glufosinate program improved control of glyphosate-resistant Palmer amaranth, with one 

and two applications of dicamba being equally effective. Late-season control of 

glyphosate-resistant Palmer amaranth was 93 to 100% with glufosinate systems including 

one or more dicamba applications. The researcher suggested grass control could be 

improved in fields with heavy grass pressure by replacing one application of glufosinate 

plus dicamba with glyphosate plus dicamba in sequential programs. Cotton yields were 

generally greater with treatments including dicamba PRE suggesting reduced early season 

weed completion with dicamba PRE.

 Field trials were conducted at seven locations in southeastern and Midsouth states in 

2011 to determine the effects of the timing of sequential dicamba applications on the 

control of mixed populations of glyphosate-resistant and –susceptible Palmer amaranth 

(Weirich et al., 2012). When applied to 3-inch plants, all sequential applications of 

dicamba (0.5 lbs. a.e./acre) provided 90 to 92% control, regardless of the absence or 

presence of glyphosate as a tank mix partner. Control was reduced when the initial 

dicamba applications were made to 9-inch plants. When applied to 9-inch plants, 

sequential applications of dicamba plus glyphosate provided from 81 to 85% control. 

No significant differences in control were observed between sequential applications 

(tested intervals were 4, 7, or 14 days).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 602 of 946

 Clemson University conducted a study in 2011 to determine the effectiveness of 

dicamba-based weed management programs for Palmer amaranth control (Marshall, 

2012). Various PRE/POST and POST only programs were evaluated. Dicamba (0.5 

lbs. a.e./acre), fomesafen, and dicamba (0.5 lbs. a.e./acre) plus fomesafen applied PRE 

provided excellent early season control of Palmer amaranth. When these PRE 

treatments were followed with EPOST and LPOST applications of glyphosate plus 

dicamba (0.5 lbs. a.e./acre) or glufosinate plus dicamba (0.5 lbs. a.e./acre), all these 

programs provided 100% control of Palmer amaranth at 35 days after the LPOST 

application. These POST treatments also provided 100% control when no PRE 

treatments were used. 

B.3.5.2.2. Improved Control of Hard-to-Control Broadleaf Weed Species

Dicamba use on DGT cotton offers a new management tool for improved control of hardto-control weed species in cotton (Keeling et al., 2012; Marshall 2012). Certain problematic 

broadleaf weed species in certain areas of the U.S. are naturally less sensitive to glyphosate, 

namely morningglory spp., hemp sesbania, prickly sida, and purslane are generally hard to 

control with postemergence applications of glyphosate alone. Alternative broadleaf 

postemergence cotton herbicides (fluometuron, pyrithiobac, and thifloxsulfuron) provide 

inconsistent or less than acceptable control of these problematic broadleaf species in cotton. 

(See Table B-23 of this appendix; see also Appendix A). Postemergence applications of a 

glyphosate plus dicamba tank mixture or glufosinate plus dicamba will improve the control 

of these hard-to-control broadleaf weed species compared to glyphosate alone. Also, the 

control with the glyphosate plus dicamba mixture will often exceed the control of glyphosate 

mixtures with other commercial standards on certain of these weed species. With the 

research emphasis on glyphosate-resistant Palmer amaranth, limited data is currently 

available on other broadleaf weed species.

An experiment was conducted in Texas in 2011 on two hard-to-control broadleaf weeds –

glyphosate-susceptible smellmelon (Cucumis melo) and ivyleaf morningglory (Ipomoea hederacea) 

(Cogdill and Chandler, 2012). Preemergence applications of dicamba alone provided 40 to 

50% reduction in broadleaf weed emergence. Dicamba tank mixed with glyphosate or 

glufosinate applied postemergence improved broadleaf weed control to over 90% compared 

to glyphosate or glufosinate alone with less than 80% control.

Studies conducted by Clemson University in 2011 demonstrated that glyphosate or 

glufosinate plus dicamba provided 93 to 100% control of pitted morningglory, regardless of 

the preemergence herbicide treatment (Marshall, 2012). The control of pitted morningglory 

was greater than 94% with these tank mixtures when no preemergence treatment was 

applied. 

Monsanto studies conducted in 2010 and 2011 showed that dicamba and glufosinate applied 

alone were effective in controlling morningglory species (Bollman et al., 2012; Voth et al., 

2012). Results also showed that a number of dicamba, glufosinate, and glyphosate herbicide 

combinations provided excellent broad-spectrum weed control throughout the season and 

the most consistent results were achieved when a preemergence residual herbicide was
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 603 of 946

included in the weed management program. In locations where annual grasses were present, 

treatments containing glyphosate were significantly better than those that did not contain 

glyphosate. Based on the above studies, in-crop applications of dicamba herbicide would be 

a beneficial addition to the weed managements systems in cotton.

B.3.5.2.3. Crop Tolerance

Weed management systems utilizing dicamba, glufosinate, and glyphosate-tolerant cotton 

have proven to be very effective in controlling a broad spectrum of weeds including 

glyphosate-resistant Palmer amaranth and other hard-to-control broadleaf weed species in 

cotton. Weed control systems must also display good crop tolerance to the herbicides to 

allow cotton to reach full yield potential. Dicamba, glufosinate, and glyphosate-tolerant 

cotton provides good crop tolerance to dicamba applied preemergence and in-crop 

postemergence. In addition, good tolerance is displayed when dicamba is applied in various 

weed management systems when tank mixed with glyphosate or glufosinate applied early 

post and mid-post. 

Twenty-four university field experiments and approximately 27 Monsanto field experiments 

were conducted on dicamba, glufosinate, and glyphosate-tolerant cotton in the Midsouth 

and Southeastern cotton growing regions of the U.S. in 2010 and 2011. Dicamba, 

glufosinate, and glyphosate-tolerant cotton demonstrated good crop tolerance to dicamba, 

glufosinate, and glyphosate when used in a weed management system. 

Low levels of cotton visual symptoms have been observed in DGT cotton. York et al. 

(2012) reported that glufosinate applied mid-post alone and in a tank mix with dicamba 

caused minor foliar necrosis at one of four study locations. There was no evidence this 

affected yield. No crop response was noted with dicamba PRE or with dicamba plus 

glufosinate or dicamba plus glyphosate applied early post. Dodds et al. (2012) reported that 

early post applications of dicamba (0.5 lbs a.e./acre) plus glufosinate or glyphosate with or 

without preemergence applications of dicamba (0.5 lbs a.e./acre) resulted in 3.5 – 4% visual 

cotton injury in five study locations. Cotton visual symptoms were greatest (~11%) with the 

following treatments: dicamba (0.5 lbs a.e./acre) preemergence followed by dicamba (0.5 lbs 

a.e./acre) early post followed by glufosinate mid-post or dicamba preemergence followed by 

glufosinate early post followed by dicamba (0.5 lbs a.e./acre) mid-post. Cotton visual 

symptoms were less than 1% with many other early post and mid-post treatments of 

dicamba tank mixtures following dicamba preemergence. No detrimental affects on seed 

cotton yields were reported. The researchers concluded that dicamba, glufosinate, and 

glyphosate-tolerant cotton demonstrated good tolerance to dicamba, glufosinate, and 

glyphosate herbicides applied alone or when tank mixed (Dodds et al., 2012).

Dicamba, glufosinate, and glyphosate-tolerant cotton demonstrated good crop tolerance to 

dicamba, glufosinate, and glyphosate when used in a weed management system. Low levels 

of foliar visual symptoms are occasionally observed as a result of glufosinate, or dicamba 

tank mix applications with glyphosate or glufosinate. No yield effects have been associated 

with the foliar visual symptoms.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 604 of 946

B.3.5.2.4. Application Flexibility with Dicamba in Dicamba, Glufosinate, and 

Glyphosate-Tolerant Cotton

Dicamba, glufosinate, and glyphosate-tolerant cotton will facilitate a wider window of 

application for dicamba in cotton and application flexibility for both preemergence and 

postemergence herbicide applications in cotton. Current labeled uses of dicamba in cotton 

are limited to early preplant applications and the current maximum rate of dicamba is 0.25 

lbs. a.e./acre. To avoid cotton injury, significant planting restrictions exist currently for 

preplant applications of dicamba in cotton. The waiting interval between application and 

planting cotton is a minimum of 21 days and a minimum accumulation of one inch of 

rainfall or overhead irrigation must occur prior to planting (BASF Corporation 2008; CDMS, 

2012). 

To support the introduction of dicamba, glufosinate, and glyphosate-tolerant cotton, 

Monsanto has submitted an application to U.S. EPA to amend Registration Number 524-

582, a DGA salt formulation of dicamba, to allow preemergence and in-crop postemergence 

applications in DGT cotton. If approved, growers will be authorized to apply dicamba alone 

or in mixtures with glyphosate, glufosinate, or other labeled herbicides in these applications. 

Dicamba would be authorized to be applied up to 1.0 lbs. a.e./acre prior to planting, up to 

the emergence of cotton, and in-crop postemergence up through seven days prior to harvest 

at up to 0.5 lbs. a.e./acre. 

The use pattern and rate of glufosinate on DGT cotton will follow the existing glufosinatetolerant cotton uses outlined on the glufosinate herbicide label (Bayer Crop Science 2007). 

Consequently, Monsanto will not pursue any changes in the glufosinate label or the 

established tolerances for its use on DGT cotton. 

B.3.5.2.5. Proactive Program for Weed Resistance Management

With the potential for continued selection pressure on glyphosate and other frequently used 

cotton herbicides (e.g., SU and PPO herbicides), additional modes-of-actions are needed to 

mitigate the potential for the development and spread of these resistant weed species. 

University weed control specialists conducting the evaluation of dicamba, glufosinate, and 

glyphosate-tolerant cotton indicate that this new technology would provide an additional 

tool and mode-of-action to control herbicide-resistant weeds and manage selection for 

additional resistance in weed species (York et al., 2012). The proposed weed management 

recommendations include the use of a preemergence residual herbicide (Tables A-24 and A25). University weed control specialists stress the importance of using several herbicides 

with different modes-of-action, including the use of residual preemergence herbicides, to 

maximize the long-term sustainability and utility of the currently available cotton herbicides 

(Culpepper et al., 2011; Dodds et al., 2012).

B.3.5.2.6. Preserves conservation tillage benefits

The benefits of conservation tillage are well known, namely reduced labor, savings of time 

and fuel, improved soil health, reduced soil erosion, and improved water quality – as well as 

air quality benefits from reduced use of farm machinery (CTIC, 2012a; Price et al., 2011). 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 605 of 946

Conservation tillage systems are well established in cotton production, with 34% of the 

cotton acres utilizing some form of conservation tillage (Monsanto, 2012). Glyphosatetolerant cotton has been a primary enabler for continued adoption of conservation tillage 

systems and for the success of USDA Natural Resource Soil Conservation (NRCD) 

programs (CAST, 2011). Weed resistance to glyphosate in certain areas is a threat to soil 

conservation gains in some situations (CAST, 2011; Price et al., 2011). In particular, 

glyphosate-resistant Palmer amaranth is difficult to manage in no-tillage systems with 

currently available herbicide systems. Controlling glyphosate-resistant Palmer amaranth 

solely with herbicides is no longer an effective management approach in some cotton 

producing areas (Culpepper et al., 2012). Dicamba, glufosinate, and glyphosate-tolerant 

cotton will assist in preserving the use of conservation tillage and the benefits growers and 

the environment realize from utilizing these systems by enabling effective management of 

glyphosate-resistant weed species and other hard-to-control weeds in areas of the U.S. where 

they occur.

The use of dicamba and glufosinate applications in a diversified weed management in 

dicamba, glufosinate, and glyphosate-tolerant cotton provides excellent control of 

glyphosate-resistant Palmer amaranth in cotton. This combined with the herbicide 

application flexibility of the dicamba, glufosinate, and glyphosate-tolerant cotton system will 

benefit no-tillage and other conservations tillage systems for cotton, and enable growers to 

return to conservation tillage systems that they may have abandoned because of inadequate 

control of glyphosate-resistant weeds in certain areas of the U.S. 

B.3.5.3. Conclusion

Dicamba, glufosinate, and glyphosate-tolerant cotton will enable an additional weed 

management tool for effective and sustainable weed management in cotton production. 

Dicamba, glufosinate, and glyphosate-tolerant cotton will allow growers to use dicamba, 

glufosinate, and glyphosate herbicides in a diversified weed management program to control 

a broad spectrum of grass and broadleaf weed species. Dicamba tolerance facilitates a wider 

window of application, as well as application flexibility for both preemergence and 

postemergence applications in cotton compared to current labeled uses of dicamba in 

cotton. A significant number of field studies conducted by university weed control specialist 

in the major cotton production regions in 2010 and 2011 have led to the development of 

weed management system recommendations for dicamba, glufosinate, and glyphosate 

tolerant cotton. These system recommendations will provide for effective and sustainable 

management of weeds in cotton, including glyphosate-resistant Palmer amaranth. In 

addition, weed control systems in dicamba, glufosinate, and glyphosate-tolerant cotton will 

improve management of certain hard-to-control broadleaf weed species which are known to 

be problematic in cotton production, such as horseweed, morningglory spp., hemp sesbania, 

prickly sida, and purslane. Dicamba, glufosinate, and glyphosate-tolerant cotton has 

demonstrated good crop tolerance to dicamba and glufosinate in numerous university and 

Monsanto field experiments when evaluated in the various proposed weed management 

systems and in stand-alone tolerance trials.

Dicamba, glufosinate, and glyphosate-tolerant cotton provides three modes-of-action for 

improved weed control and weed resistance management. Use of dicamba, glufosinate, and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 606 of 946

glyphosate in-crop will help preserve the value of glyphosate and other existing pre- and 

postemergent herbicides, including glufosinate, by reducing the development of herbicideresistant weeds. Weed resistance to glyphosate in certain areas of the U.S. is a growing 

threat to gains made in soil conservation practices after the introduction of glyphosatetolerant cotton. Diversified weed management practices enabled by dicamba, glufosinate, 

and glyphosate-tolerant cotton provide excellent control of glyphosate-resistant and other 

problematic weeds and will help preserve conservation tillage usage and its well documented 

environmental and economic benefits in cotton.

All of these benefits strongly support the need for DGT cotton as a new and beneficial tool 

for cotton growers in the U.S.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 607 of 946

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Monsanto Company 10-SY-210U / 12-CT-244U-S Page 626 of 946

APPENDIX C: EFFECTS OF CHANGES IN FARMING PRACTICES ON 

WATER, SOIL AND AIR DUE TO USE OF DT SOYBEANS AND DGT 

COTTON
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Table of Contents 

C.1. Introduction..............................................................................................................................630

C.1.1. DT Soybean and DGT Cotton...........................................................................................630

C.1.1.1. Comparative Analysis........................................................................................................631

C.2. Background Dicamba ..............................................................................................................631

C.2.1. Dicamba Chemical Name and Structure ...........................................................................631

C.2.2. Dicamba Herbicide Class and Herbicidal Mode-of-Action............................................632

C.2.3. Dicamba - Current U.S. Uses..............................................................................................632

C.2.4. Proposed Use Pattern for Dicamba on DT Soybean and DGT Cotton......................632

C.3. Herbicides – Environmental Properties...............................................................................633

C.3.1. Environmental Properties of Dicamba..............................................................................633

C.3.2. Ecological Properties of Dicamba......................................................................................634

C.4. Alternative Herbicides.............................................................................................................637

C.4.1. Alternative Herbicides for Soybean ...................................................................................637

C.4.2. Alternative Herbicides for Cotton......................................................................................646

C.5. Comparative Analysis for Water Impacts.............................................................................656

C.5.1. Soybean Analysis...................................................................................................................656

C.5.1.1. Groundwater Comparison................................................................................................656

C.5.1.2. Surface water and ecological effects on aquatic organisms .........................................661

C.5.2. Cotton Analysis.....................................................................................................................668

C.5.2.1. Groundwater Comparison................................................................................................668

C.5.2.2. Surface Water and Ecological Effects on Aquatic Organisms....................................670

C.5.3. Comparative Analysis of Potential Effects on Soil, Water and Air: Dicamba 

and Alternative Herbicides..............................................................................................................675

C.5.3.1. Effects on Soil ....................................................................................................................675
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C.5.3.2. Effects on Surface Water and Groundwater .................................................................675

C.5.3.3. Potential Air Impacts ........................................................................................................677

C.6. Conservation Tillage: Potential Benefit of DT Soybean and DGT Cotton to 

Soil, Water and Air...........................................................................................................................677

C.7. Potential Impacts of Genetic Modifications to Soil, Water and Air ................................678

C.7.1. Potential Impacts from DT Soybean .................................................................................678

C.7.2. Potential Impacts from DGT Cotton................................................................................679
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Tables and Figures

Figure C-1. Structure of Dicamba ................................................................................................631

Table C-1. Environmental Fate and Physical/Chemical Properties of Dicamba Acid ........634

Table C-2. Dicamba Acid Ecotoxicity Findings on Mammals, Birds and Fish (U.S. EPA. 

2005a) ...................................................................................................................................635

Table C-3. Dicamba Acid Ecotoxicity Findings on Aquatic and Terrestrial Invertebrates 

(U.S. EPA. 2005a)...............................................................................................................636

Table C-4. Dicamba Acid Ecotoxicity Results on Aquatic and Terrestrial Plants (U.S. EPA. 

2005a) ...................................................................................................................................636

Table C-5. Dicamba, Diglycolamine (DGA) Salt Ecotoxicity Findings (U.S. EPA. 2005a) 637

Table C-6. Alternative Registered Soybean Herbicides.............................................................639

Table C-7. Active Ingredients Contained in Alternative Herbicides.......................................644

Table C-8. Dicamba and Alternative Registered Cotton Herbicides........................................648

Table C-9. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide 

Products...............................................................................................................................654

Table C-10. Groundwater and Leaching Parameters for Dicamba and Alternate Active 

Ingredients...........................................................................................................................659

Table C-11. Aquatic Toxicity Parameters for Fish and Aquatic Invertebrates for Alternative 

Herbicides............................................................................................................................663

Table C-12. Aquatic Toxicity Parameters for Aquatic Plants for Alternative Herbicides....667

Table C-13. Aquatic Toxicity for Fish and Aquatic Invertebrates from Acute Exposure ...672

Table C-14. Aquatic Toxicity Parameters for Aquatic Plants for Dicamba and Alternate 

Herbicide Active Ingredients............................................................................................674
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C.1. Introduction

Dicamba is a selective broadleaf herbicide belonging to the auxin agonist class, the oldest 

known class of synthetic herbicides, and is a member of the benzoic acids sub-group. 

Dicamba mimics the action of the plant hormone indole acetic acid and causes rapid 

uncontrolled cell division, and growth leading to plant death. Dicamba has been registered 

for agricultural uses in the U.S. since 1967 and has been widely used in agricultural 

production for over forty years. Dicamba is presently approved for use on asparagus, corn, 

cotton, grass seed production, pasture and rangeland grasses, small cereals including barley, 

oats, rye, and wheat, sorghum, soybean, and sugarcane. Dicamba is also used for industrial 

vegetation management (e.g., forestry and roadsides), professional turf management (e.g., 

golf courses, sports complexes), and residential turf (U.S. EPA, 2009b). Dicamba provides 

effective control of over 95 annual and biennial weed species, and control or suppression of 

over 100 perennial broadleaf and woody plant species.

C.1.1. DT Soybean and DGT Cotton

Monsanto Company has developed biotechnology-derived soybean that is tolerant to 

dicamba (3,6-dichloro-2-methoxybenzoic acid) herbicide (DT soybean) and biotechnologyderived cotton that is tolerant to dicamba and glufosinate (DGT cotton). 

DT soybean offers growers expanded use of dicamba in soybean production. The crop 

tolerance of DT soybean to dicamba facilitates a wider window of application in soybean, 

allowing preemergence application any time up to soybean emergence (cracking), and two incrop postemergence applications up to 0.5 lb a.e. per acre per application through the early 

reproductive R1 stage of growth. DGT cotton offers growers expanded use of dicamba in 

cotton production. The crop tolerance of DGT cotton to dicamba also enables a wider 

window of application; dicamba would be authorized to be applied up to 1.0 lb a.e. per acre 

any time prior to cotton emergence, and postemergence in-crop application up to 0.5 lbs a.e. 

per acre per application up through seven days prior to harvest.

Using traditional breeding techniques, DT soybean will be combined with glyphosatetolerant soybean and DGT cotton will be combined with glyphosate-tolerant cotton. The 

combination of herbicide-tolerance traits allows the use of dicamba and glyphosate (and, in 

the case of DGT cotton, glufosinate) herbicides in an integrated weed management program 

to control a broad spectrum of grass and broadleaf weed species. For DT soy, the two 

herbicides can be used in sequence or tank-mixed. For DGT cotton, the herbicides can be 

used in sequence, or dicamba can be tank-mixed with either glyphosate or glufosinate. 

Monsanto has submitted to U.S. EPA applications to amend Registration Number 524-582 

to register new use patterns for dicamba on DT soybean and DGT cotton to expand the 

existing window of application as described above. The use pattern and rate of glufosinate 

on DGT cotton will follow the existing glufosinate-tolerant cotton uses outlined on the 

glufosinate herbicide label.

The availability of DT soybean and DGT cotton integrated into the glyphosate-tolerant 

soybean and cotton systems will result in a simple and effective dual or triple mode-of-action 

herbicide system that will control hard-to-control broadleaf weeds, assist in the management 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 631 of 946

of resistant broadleaf weeds, including glyphosate-resistant weeds, and subsequently displace 

some soybean and cotton herbicides currently in use today (also referred to as alternative 

herbicides). 

C.1.1.1. Comparative Analysis

The intent of this comparative analysis is to define current herbicide use in U.S. soybean and 

cotton production, and to compare dicamba’s potential impacts on water, soil and air to 

herbicides currently used by growers for weed control. In order for a pesticide (e.g, dicamba 

herbicide) to be registered by U.S. EPA it must meet the FIFRA and FFDCA standards for 

safety to human health and the environment. The U.S. EPA must conclude that the 

herbicide when used according to the label does not pose an unreasonable risk to humans or 

the environment. Therefore, all alternative herbicides used in soybean and cotton production 

can be used safely, and do not pose an unreasonable risk to humans or the environment. 

Nonetheless, in some instances dicamba offers a reduction in risk potential (i.e., hazard) 

compared to some alternative herbicides in the same risk category (e.g., aquatic plant risk). 

In other instances dicamba presents a similar risk potential compared to the some 

alternatives, and in some instances, dicamba presents a greater risk potential compared to 

some alternatives. This comparative assessment serves to demonstrate that the use of 

dicamba on DT soybeans is unlikely to result in a significant impact/risk to human health or

the environment compared to current herbicide agronomic practices, and in some instances 

its use may impart additional benefits as described in this Environmental Report.

C.2. Background Dicamba

C.2.1. Dicamba Chemical Name and Structure

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is a carboxylic acid that can form salts in 

aqueous solution. The chemical structure is provided in Figure C.1. Dicamba products 

registered for agricultural uses are formulated with various dicamba salts. The formulated 

products Clarity and M1691 contain the diglycolamine (DGA) salt of dicamba at a nominal 

level of 56.8% by weight, which is equivalent to 38.5% by weight dicamba acid (also referred 

to acid equivalents or a.e.). 

O

CH3

Cl

Cl

O OH

Figure C-1. Structure of Dicamba
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 632 of 946

C.2.2. Dicamba Herbicide Class and Herbicidal Mode-of-Action

Dicamba belongs to the “benzoic acid class” of herbicides. The Weed Science Society of 

America (WSSA) places dicamba in herbicide group number 4.113 It is an auxin agonist; it is 

a plant hormone (indole acetic acid, IAA) mimic that causes rapid uncontrolled cell division 

and growth, leading to plant death. Dicamba is mainly used to control broadleaf weeds and 

woody plants.

C.2.3. Dicamba - Current U.S. Uses 

Dicamba is a selective herbicide labeled for control of certain broadleaf weeds and woody 

plants. It was first registered for agricultural use in the U.S. in 1967 and is widely used today 

in agricultural, industrial, and residential settings. Dicamba salts have approved uses on 

asparagus, corn, cotton, grass seed production, pasture and rangeland grasses, small cereals 

including barley, oats, rye, and wheat, sorghum, soybean, and sugarcane. Dicamba is also 

used for industrial vegetation management (e.g., forestry and roadside right-of-ways), 

professional turf management (e.g., golf courses, sports complexes), and residential turf (U.S. 

EPA, 2009b; Durkin and Bosch, 2004). 

C.2.4. Proposed Use Pattern for Dicamba on DT Soybean and DGT Cotton

Monsanto has submitted two applications to U.S. EPA to amend Registration No. 524-582, 

a low-volatility DGA salt formulation for new use patterns, one for DT soybean and one for 

DGT cotton. 

DT Soybean. The proposed new use pattern allows for sequential applications of dicamba, 

formulated as the DGA salt, to DT soybean:

 Preplant / preemergent applications, totaling up to 1.0 pound per acre of dicamba 

a.e. 

 One or two postemergent in-crop applications (up to 0.5 pounds a.e. per acre each), 

timed between soybean emergence (cracking) and early flowering (R1 growth stage) 

of the soybean. 

 Maximum annual application rate of 2.0 pounds dicamba a.e. per acre.

The proposed use pattern for dicamba on DT soybean is within the maximum single and 

annual application rates that have previously been assessed by EPA. 

 

113 There are several systems of herbicide mode-of-action classification. Among the most widely used are those of the 

Herbicide Resistance Action Committee (HRAC) and the WSSA. The classifications are compared in a chart at: 

http://www.plantprotection.org/HRAC/Bindex.cfm?doc=MOA.html. Accessed May 27, 2010
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 633 of 946

DGT Cotton. The proposed new use pattern allows for sequential applications of dicamba, 

formulated as the DGA salt, to DGT cotton:

 Preplant / preemergent applications, totaling up to 1.0 pound per acre of dicamba 

a.e. 

 Postemergent in-crop applications (up to 0.5 pounds a.e. per acre each), up to 7 days 

prior to harvest. 

 Maximum annual application rate of 2.0 pounds dicamba a.e. per acre.

The proposed application rates associated with both DT soybean and DGT cotton would be 

less than or equivalent to rates for dicamba established for other uses in the dicamba RED 

including the 2.0 lbs a.e. dicamba per year for all applications (U.S. EPA 2009a). Once 

approved by U.S. EPA, these labels will become legally-binding constraints on the use of 

dicamba on DT soybean and DGT cotton.

C.3. Herbicides – Environmental Properties

The environmental fate and transport of a herbicide depends on its persistence (measured by 

half-life) and its mobility. Herbicides may be degraded by microorganisms, by reaction with 

other chemicals (including water, oxygen or others), or by sunlight. After application, an 

herbicide may absorb to soil or vegetation particles, dissolve in water, or volatilize. Soil 

particles may stay in place, or may erode by wind or water. Water containing dissolved 

herbicides may be taken up by plants, run off into surface water, or infiltrate into the 

subsurface or groundwater. The potential for an herbicide to persist in the soil and 

potentially runoff or move to groundwater are based on its soil degradation and affinity to 

bind with soil. EPA will use the herbicide’s environmental fate and physical/chemical 

properties to determine the risk potential to aquatic and terrestrial species.

C.3.1. Environmental Properties of Dicamba

Table C-1 summarizes the physical and chemical properties of dicamba that can influence its 

mobility and persistence in the environment. These measures are the result of conventional 

laboratory testing, as required for U.S. EPA registration. Results are presented using 

standard environmental fate indices, such as the time required for 50% degradation (half-life) 

of the initial concentration. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 634 of 946

Table C-1. Environmental Fate and Physical/Chemical Properties of Dicamba Acid

Environmental Physical Properties Results 

Dicamba acid vapor pressure 3.4 x 10-5torr (25° C)

Dicamba acid acidity (pKa) 1.87

Dicamba acid water solubility 6100 mg/L

Dicamba acid octanol / water partition coefficient 0.1

Dicamba acid Koc (Freundlich soil-binding constant) 3.5 – 21.1 mL/g

Dicamba acid field dissipation half-life (conducted with 

salt formulations)

3 – 19.8 days

Dicamba acid aerobic soil half-life, Laboratory 6 days

Dicamba acid anaerobic soil half-life, Laboratory 141 days

Dicamba acid aerobic aquatic half-life, Laboratory 20.2 – 24.3 days

Dicamba acid aqueous photolysis half-life 38.1 days

Dicamba acid soil photolysis degradation rate ~20% after 30 days

Hydrolysis half-life Stable

Dicamba (dicamba acid/DGA salt) has a Groundwater Ubiquitous Score (GUS), a 

groundwater leaching index, of 2.6 indicating moderate leachability. (Gustafson, 1989 as 

cited in Monsanto, 2013. See Appendix A, Section IV.D.2). 

C.3.2. Ecological Properties of Dicamba

The following tables summarize the hazard potency of dicamba to non-target species. These 

data were taken from the Environmental Fate and Effects Division (EFED) Chapter of the 

dicamba RED (U.S. EPA, 2005a). These measures are the result of conventional laboratory 

testing against standard indicator species of fish, birds, mammals, and plants as required for 

EPA registration. Results are presented using standard toxicity indices, such as the 

concentration or dose required for 50% lethality (LC50 or LD50) or the concentration required 

for a 25 or 50% reduction in growth or biomass (EC25 or EC50). In some cases the “No 

Observable Effect Concentration” (NOEC) or “No Observable Adverse Effect Level” 

(NOAEL) is also listed. A summary of the findings of the ecotoxicity studies conducted on 

dicamba acid is provided in Tables C-2 through C-4. Ecotoxicity studies have also been 

conducted on the diglycolamine (DGA) salt of dicamba and are summarized in Table C-5.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 635 of 946

Table C-2. Dicamba Acid Ecotoxicity Findings on Mammals, Birds and Fish (U.S. 

EPA. 2005a)

Study Toxicity Endpoint 

Mammals

Dicamba acid acute oral (rat) LD50 2740 mg/kg body wt

Multigeneration reproduction (rat) 

NOAEL/LOAEL

45 /136mg/kg/day

Birds

Dicamba acid acute oral (quail) LD50 188 mg/kg body wt

Dicamba acid acute oral (duck) LD50 1373 mg/kg body wt

Dicamba acid sub-acute oral (quail) LC50 >10,000 mg/kg diet

Dicamba acid sub-acute oral (duck) LC50 2009 mg/kg diet

Dicamba acid sub-acute oral (duck) LC50 >10,000 mg/kg diet

Dicamba acid reproduction (quail) NOEC/LOEC 1390 (HDT1) mg/kg diet

Dicamba acid reproduction (duck) NOEC/LOEC 695/1390mg/kg diet

Fish

Dicamba acid (trout) LC50 28 mg/L

Dicamba acid (trout) LC50 135 mg/L

Dicamba acid (trout) LC50 153 mg/L

Dicamba acid (Bluegill) LC50 135 mg/L

Dicamba acid (Bluegill) LC50 >50 mg/L

Dicamba acid (Sheepshead) LC50 >180 mg/L

Dicamba acid fish early life stage NA

Dicamba acid fish life cycle NA

NA denotes Not Applicable.

NOEC stands for No Observable Effect Concentration. 

LOEC stands for Lowest Observable Effect Concentration.

1HDT stands for the Highest Dose Tested.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 636 of 946

Table C-3. Dicamba Acid Ecotoxicity Findings on Aquatic and Terrestrial 

Invertebrates (U.S. EPA. 2005a)

Study Toxicity Endpoint Comment

Aquatic Invertebrates

Dicamba acid (Daphnia) LC50 111 mg/L

Dicamba acid (Daphnia) LC50 >100 mg/L Replicate

Dicamba acid (Sowbug) LC50 >100 mg/L

Dicamba acid (Scud) LC50 >100 mg/L

Dicamba acid (Grass Shrimp) LC50 >132 mg/L

Dicamba acid (Fiddler Crab) LC50 >173 mg/L

Dicamba acid (Oyster) LC50 >1 mg/L

Dicamba acid (Glass Shrimp) LC50 >56 mg/L

Invertebrate life cycle NA

Terrestrial Invertebrates

Honeybee LD50 >90.6 μg/bee

NA denotes Not Applicable.

Table C-4. Dicamba Acid Ecotoxicity Results on Aquatic and Terrestrial Plants 

(U.S. EPA. 2005a)

Study Toxicity Endpoint Comment

Aquatic Plants

Dicamba acid duckweed EC50 / NOEC >3.25 / 0.2 mg/L

Dicamba acid green alga EC50 / NOEC >3.7 / 3.7 mg/L

Dicamba acid marine diatom EC50 / NOEC 0.49 / 0.011 mg/L

Dicamba acid blue-green alga EC50 / NOEC 0.061 / 0.005 mg/L

Dicamba acid freshwater diatom EC50 / NOEC 2.3 / 0.5 mg/L

Terrestrial Plants

Dicamba acid seedling emergence monocot EC25 / 

NOEC

0.004 / <0.032 lb/a Onion

Dicamba acid seedling emergence dicot EC25 / 

NOEC 

0.0027 / < 0.0022 lb/a Soybean

Dicamba acid vegetative vigor monocot EC25 / 

NOEC

0.15/ 0.13 lb/a Onion

Dicamba acid vegetative vigor dicot EC25 / NOEC 0.0068 / <0.004 lb/a Soybean
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 637 of 946

Table C-5. Dicamba, Diglycolamine (DGA) Salt Ecotoxicity Findings (U.S. EPA. 

2005a)

Study Toxicity Endpoint Comment

Birds 

Dicamba DGA salt acute oral (quail) LD50 262 mg a.e./kg body 

weight

Dicamba DGA salt sub-acute oral (quail) LC50 >1522 mg a.e./kg diet

Dicamba DGA salt sub-acute oral (duck) LC50 >1522 mg a.e./kg diet

Fish

Dicamba DGA salt (trout) LC50 >270mg a.e./L

Dicamba DGA salt (bluegill) LC50 >270mg a.e./L

Aquatic Invertebrates

Dicamba DGA salt (Daphnia) LC50 >270 mg a.e./L

 

C.4. Alternative Herbicides

C.4.1. Alternative Herbicides for Soybean 

If DT soybean is not integrated into the glyphosate-tolerant soybean system, the potential 

for glyphosate-resistant weed populations to evolve and develop in soybean producing areas 

may increase. In addition, the potential for resistance to evolve and develop for other 

herbicides used in soybean production could also increase in these areas where growers do 

not use multiple modes-of-action. The increased use of other non-glyphosate alternative 

herbicides would also be expected. The DT soybean combined with the glyphosate-tolerant 

soybean system will result in a simple and effective dual mode-of-action herbicide system 

that will control hard-to-control broadleaf weeds, assist in the management of resistant 

broadleaf weeds, including glyphosate-resistant biotypes, and has the potential to eliminate 

the need for some soybean herbicides currently in use today. As a result, DT soybean 

combined with the glyphosate-tolerant soybean system will provide benefits to the soybean 

grower that current weed control options do not have, such as:

 Effective tool for sustainable management of glyphosate resistant weeds; 

 Mitigate the potential for the evolution development of weed resistance for all 

classes of soybean herbicides; 

 Improve the consistency of control over hard-to-control weeds, thereby reducing the 

potential for new resistant biotypes to develop;

 Increase application flexibility; 

 Preserve the benefits of the Roundup Ready weed control system; and

 Preserve the many environmental and economic benefits of conservation tillage 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 638 of 946

As discussed in Appendix A.3.7.2 of this Environmental Report, ninety-seven percent 

(97%) of soybean treated acres receive an application of glyphosate; the remaining acres are 

treated with more than 25 other active ingredients. In some of the soybean acres, these 

other active ingredients are applied on acres that also receive a glyphosate application. 

Integration of DT soybean into the glyphosate-tolerant soybean system and the subsequent 

use of dicamba will result in the displacement of some currently used, or foreseeable future 

use herbicides, and therefore the properties of these alternative herbicides are summarized in 

this section to provide a baseline for comparison to dicamba use on DT soybean. 

Table C-6 summarizes key information from alternate herbicide product labels. 

Table C-7 lists the eighteen active ingredients that make up the products in Table C-6. 

Tables C-6 and C-7 are the same as Tables A-24 and Table A-25 in Appendix A. 2,4-D, 

being used primarily as a pre-plant application, is the most widely-used herbicide in this 

alternate herbicide list, representing about 10% of treated acres; whereas acifluorfen, 

carfentrazone-ethyl, and flufenacet are the least used among these, representing <0.5% of 

treated acres. Mesotrione has not been used in soybean production previously; the use on 

soybean was only recently registered by the EPA (2009d). Table C-7 also lists general 

regulatory information about each herbicide. Note that only paraquat is classified as a 

Restricted Use pesticide among this group, on the basis of acute toxicological concern. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 639 of 946

Table C-6. Alternative Registered Soybean Herbicides

Brand

(U.S. EPA Reg. 

No.)

Active Ingredient Signal 

Word1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. 

Soybean lb/a 

(single 

treatment)3

Max. 

Soybean 

lb/a 

(season)

Label Warnings or Special Directions4

Aim® (279-3241) CarfentrazoneethylCaution 2 lb/gal 12 hr 0.008 5 0.023 "toxic to fish";"toxic to algae"; V3 - V10; do not feed 

foliage; some burn injury

Authority® First 

DF (279-3246)

Sulfentrazone Caution 0.62 lb/lb 12 hr 0.31 0.31 "known to leach"; "toxic to marine / estuarine 

invertebrates.";65-day PHI; crop rotation restrictions, 

up to 30 mts; soil O.M. limits (sands <1% organic 

matter)

Cloransulammethyl0.08 lb/lb 0.04 0.04

Authority MTZ 

(279-3340)

Sulfentrazone Caution 0.18 lb/lb 12 hr 0.028 0.046 "known to leach"; "toxic to marine / estuarine 

invertebrates. 120-day PHI (not Over The Top); 

sensitive varieties, injury possible

Metribuzin 0.27 lb/lb 0.042 0.07

Basagran®

(7969-45)

Bentazon Caution 4 lb/gal 48 hr 1 2 "known to leach";30-day PHI for feeding treated 

forage and hay; minor injury

Butoxone® 7500 

(71368-49)

2,4-DB Caution 0.75 lb/lb 48 hr 0.375 soil type limits

Butyrac® 200 

(42750-38)

2,4-DB DMA salt Danger 2 lb/gal 48 hr 0.4 0.4 "toxic to fish";60-day PHI; injury may occur, 

especially with tank mixtures

Cadet® (279-3338) Fluthiacet-methyl Warning 0.91 lb/gal 12 hr 0.0065 0.009 do not feed foliage; minor injury

Callisto® (100-

1131) 

Mesotrione Caution 4 lb/gal 12 hr 0.1875 0.1875 “high potential for runoff”; crop rotation restrictions 

up to 18 mts; "transient bleaching" may occur; preemergence use only, no in crop use
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 640 of 946

Table C-6 (continued). Alternative Registered Soybean Herbicides

Brand

(U.S. EPA Reg. 

No.) Active Ingredient

Signal 

Word1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. 

Soybean lb/a 

(single 

treatment)3

Max. 

Soybean 

lb/a 

(season) Label Warnings or Special Directions4

Classic® (352-

436)

Chlorimuron-ethyl Caution 0.75 lb/lb 12 hr 0.14 0.14 6 60-day PHI; crop rotation restrictions up to 30 mts 

and complicated description of 3 different intervals

specific to US regions and soil pH; do not feed 

foliage; soil type limits; "temporary leaf yellowing"

Cobra® (59369-

34)

Lactofen Danger 2 lb/gal 12 hr 0.2 0.4 6 "toxic to fish"; Do not apply past soybean growth 

stage R6 / 45-day PHI; minor injury

Extreme ®

(241-405)

Imazethapyr Warning 0.17 lb/gal 48 hr 0.064 6 0.064 6 "properties & characteristics associated with chemicals 

detected in ground water"; crop rotation limits

Glyphosate-IPA 2 lb/gal 0.75 0.75

FirstRate 

(62719-275)

CloransulammethylCaution 0.84 lb/lb 12 hr 0.04 0.055 65-day PHI; crop rotation restrictions up to 30 mts; 

soil types; 14-day forage and hay feeding restriction

Flexstar ®

(100-1101)

Fomesafen Warning 1.88 lb/gal 24 hr 0.35 0.375 6 "cause tumors"; "known to leach"; 45-day PHI; do 

not feed foliage; crop rotation limits

Gangster ® Copack (59639-

131)

Flumioxazin Caution 51% 12 hr 0.096 0.096 "toxic to aquatic invertebrates."; "Preemergent only. 

“properties & characteristics Associated with 

chemicals detected in ground water"; "toxic to 

invertebrates."

Cloransulammethyl84% 0.032 0.032

Gramaoxone 

Inteon ® (100-

1217)

Paraquat dichloride Danger 2 lb/gal 

(cation 

basis)

12 hr 1.5 2.9 "toxic to wildlife"; Restricted Use; no Over-the-Top 

use
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 641 of 946

Table C-6 (continued). Alternative Registered Soybean Herbicides 

Brand 

(U.S. EPA Reg. 

No.) Active Ingredient

Signal 

Word1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. 

Soybean lb/a 

(single 

treatment)3

Max. 

Soybean 

lb/a 

(season) Label Warnings or Special Directions4

Ignite® (264-

829)

GlufosinateammoniumWarning 2.34 lb/gal 12 hr 0.66 0.8 "runoff potential"; "toxic to vascular plants"; 70-day 

PHI; some crop rotation limits up to 180 days; only 

Over-the-Top to Liberty Link soybean

Liberty® (264-

660)

GlufosinateammoniumWarning 1.67 lb/gal 12 hr 0.44 0.8 "runoff potential"; "toxic to vascular plants"; 70-day 

PHI; do not feed foliage; crop rotation limits up to 

120 days;

Phoenix®

(59639-118)

Lactofen Caution 2 lb/gal 12 hr 0.3 0.4 6 "toxic to fish"; Do not apply past crop growth stage 

R6 / 45-day PHI; minor injury

Pursuit® (241-

310)

Imazethapyr Caution 2 lb/gal 4 hr 0.063 0.063 "properties & characteristics associated with 

chemicals detected in ground water"; 85-day PHI; do 

not feed forage and hay

Pursuit® Plus 

(241-331)

Pendimethalin Caution 2.7 lb/gal 24 hr 0.84 0.84 "properties & characteristics associated with 

chemicals detected in ground water"; "toxic to fish"; 

85-day PHI; crop rotation limits up to 40 months

Imazethapyr 0.2 lb/gal 0.063 0.063

Raptor ® (241-

379)

ImazamoxammoniumCaution 1 lb/gal 4 hr 0.04 0.04 "phytotoxic to all plants"; plantback / crop rotation 

limits up to 26 months, two regions with complicated 

warnings
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 642 of 946

Table C-6 (continued). Alternative Registered Soybean Herbicides 

Brand

(U.S. EPA Reg. 

No.) Active Ingredient

Signal 

Word 1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. 

Soybean 

lb/a (single 

treatment)3

Max. 

Soybean 

lb/a 

(season) Label Warnings or Special Directions4

Reflex® (100-

993)

Fomesafen Danger 2 lb/gal 24 hr 0.375 0.375 6 "known to leach"; 45-day PHI; crop rotation limits up 

to 18 mts; minor injury, significant geographical 

restrictions (5 regions each with different rate 

structure)

Resource®

(59639-82)

Flumiclorac-pentyl Warning 0.86 lb/gal 12 hr 0.081 0.11 "toxic to shrimp"; 60-day PHI; do not feed forage or 

hay to livestock; temporary spotting or burn to 

soybean

Scepter ®70 DG 

(241-306)

Imazaquin Caution 0.7 lb/lb 12 hr 0.123 0.123 6 "properties & characteristics associated with 

chemicals detected in ground water"; 90-day PHI; do 

not feed forage or hay to livestock; crop rotation 

limits up to 40 mts; regional limitations (3 regions)

Sencor® (DF 

75%) (264-738)

Metribuzin Caution 0.75lb/lb 12 hr 0.66 6 1.3 6 "can seep or leach"; 70-day grain PHI; 40-day PHI on 

feeding forage to livestock; no Over-the-Top 

application, directed spray OK; injury in high pH or 

low O.M. soils or on certain crop varieties, crop 

rotation limits up to 18 mts

Synchrony® XP 

(352-648)

Thifensulfuron Caution 0.069 lb/lb 12 hr 0.013 0.013 45-day planting restriction applied prior to soybean 

planting / emergence; 60-day PHI; complicated crop 

rotation restrictions (3 regions, 4 intervals) with limits 

up to 30 mts; do not feed forage or hay to livestock; 

soil types; injury if adjuvants or tank mixed

UltraBlazer 

(70506-60)

Acifluorfen sodium Danger 2 lb/gal 48 hr 0.374 0.5 50-day PHI; minor injury

Chlorimuron-ethyl 0.215 lb/lb 0.04 0.04
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 643 of 946

Table C-6 (continued). Alternative Registered Soybean Herbicides 

Brand

(U.S. EPA Reg. 

No.) Active Ingredient

Signal 

Word 1

Active 

Ingredient 

Content

Re-entry 

Interval 

(REI)2

Max. 

Soybean 

lb/a (single 

treatment)3

Max. 

Soybean lb/a 

(season) Label Warnings or Special Directions4

Valor® SX 

(59639-99)

Flumioxazin Caution 0.51 lb/lb 12 hr 0.096 0.096 "runoff potential"; "toxic to aquatic invertebrates."; 

preemergence use only, no in crop use; do not feed 

forage or hay to livestock; crop rotation limit up to 

18 mts. & soil type limits; injury under cool wet 

conditions or poorly drained soil; restrictions on use 

with flufenacet, alachlor, metolachlor, or 

dimenthenamid

Valor® XLT 

(59639-117)

Flumioxazin Caution 0.3 lb/lb 12 hr 0.094 0.094 "toxic to aquatic invertebrates."; preemergence only, 

no in crop use; do not feed forage or hay to 

livestock; crop rotation limits up to 30 mts; injury 

under cool wet conditions or poorly drained soil

Chlorimuron-ethyl 0.103 lb/lb 0.032 0.032

Weedone® (650, 

638, LV4, LV6) 

and other 2,4-D 

brands (71368-3, 

-6, -10, -11, -14, 

-19)

2,4-D; 2,4-D salts; 

2,4-D esters

Varies Varies 0.93 0.93 Weedone 650 as an example: "toxic to aquatic 

invertebrates."; do not use on sandy soils (<1% O. 

M.); preplant to emerged weeds only , no in crop 

use; do not feed forage or hay to livestock.

1The EPA-required statement to convey to applicators the overall acute toxicity hazard posed by the product. Caution is more favorable than Warning, which is 

more favorable than Danger.

2The period of time following application during which worker reentry into the treated area is restricted, according to EPA’s Worker Protection Standard (WPS).

3The highest single-treatment and seasonal rates that can be applied to soybean according to the product Directions for Use label.

4Lists specific statements extracted from the product label that represent specific hazards or limitations that may reduce the utility of the product for soybean 

weed control

5Higher rates with directed / hooded sprayers.

6Regional or soil type limitations may lower this rate.

7Soybean label not yet publically available. Corn label comments are cited

PHI – preharvest interval, O. M. – organic matter, mts - months.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 644 of 946

Table C-7. Active Ingredients Contained in Alternative Herbicides

Active Ingredient

First 

Registered1

2006 Treated 

Soybean 

Acreage

(%)2

Registration 

Review 

Status3 RED Date4

Max. 

Soybean lb/a 

(single 

treatment)5

Max. 

Soybean 

lb/a 

(season)

Tolerances 

(40 CFR 

180)6

Restricted 

Use7

glyphosate salts 3-May-76 97 open 2009 Sep-93 1.5 6 364 No

dicamba-diglycolamine 

salt

2-Feb-56 <0.5 NA Jun-09, corrected 1

9 29 227 No

2,4-D acid, salts, and 

esters

3-Jun-52 10 2013 Jun-05 0.93 0.93 142 No

flumioxazin 12-Apr-2001 3 unscheduled NA 0.096 0.096 568 No

imazethapyr 30-Jan-87 3 2014 Jun-06 0.0648 0.0648 447 No

cloransulam-methyl 29-Oct-1997 1 2011 NA 0.04 0.055 514 No

chlorimuron-ethyl 4-Apr-86 4 2011 Sep-04 TRED 0.14 0.148 429 No

fomesafen 10-Apr-87 2 open 2007 TRED Aug-07 0.375 0.3758 433 No

flumiclorac-pentyl 23-Mar-94 1 open 2009 Aug-05 TRED 0.081 0.11 477 No

sulfentrazone 22-Nov-93 1 open 2009 NA 0.31 0.31 498 No

thifensulfuron 25-Apr-86 1 2011 NA 0.013 0.013 439 No

imazaquin 20-Mar-86 1 2014 TRED Dec-05 0.123 0.1238 426 No

imazamox-ammonium 17-Apr-95 <0.5 2014 NA 0.04 0.04 1223 No

paraquat dichloride 8-Jan-80 1 2012 Aug-97 1.0 2.9 205 Yes

lactofen 1-Apr-87 <0.5 open 2007 TRED Sep-03 0.3 0.4 432 No

glufosinate-ammonium 29-May-91 <0.5 open 2008 NA 0.66 0.8 473 No

2,4-DB 30-Jun-66 <0.5 2014 Jan-05 0.4 0.4 331 No

fluthiacet-methyl 14-Apr-99 <0.5 unknown NA 0.0065 0.009 551 No

acifluorfen sodium 29-May-81 <0.5 unscheduled Sep-09 0.374 0.5 383 No

Mesotrione 4-Jun-01 0.0 unscheduled NA 0.1875 0.1875 571 No
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 645 of 946

TRED denotes Tolerance Reregistration Eligibility Decision

1The date the herbicide was first approved for any use (e.g., industrial) by U.S. EPA.

2The percentage of the herbicide-treated soybean acres that were treated with each herbicide in AR, IA, IL, IN, KS, KY, LA, MI, MN, MS, MO, NE, NC, ND, 

OH, SD, TN, VA, and WI in 2006 (USDA-NASS, 2007b) .

3The herbicide’s progress in the ongoing EPA program named as Registration Review. Year indicates when the official docket was or will be opened. EPA is 

required by law to re-evaluate pesticides periodically, generally every 10-15 years.

4The date when EPA issued a Reregistration Eligibility Decision document. Reregistration was an earlier re-evaluation program designed to ensure that 

supporting data are up-to-date for a.i.s first registered before 1984. TRED means Tolerance Reassessment Eligibility Decision, which refers to an alternative review path 

that some post-1984 a.i.s followed.

5The maximum amount of the herbicide that can be applied to soybean in a single treatment or during the entire season, according to product labels.

6The number of the paragraph in the Code of Federal Regulations where that herbicide’s food and feed tolerances are listed.

7An EPA pesticide classification that restricts a product, or its uses, to use by a certificated pesticide applicator or under the direct supervision of a certified 

applicator. See 40 CFR 152.160.

8Regional or soil type limitations may lower this rate.

9Maximum treatment rates for the proposed dicamba label.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 646 of 946

C.4.2. Alternative Herbicides for Cotton

If DGT cotton is not integrated into the glyphosate-tolerant cotton system, the potential for 

glyphosate-resistant weed populations to evolve and spread in cotton producing areas may increase. 

In addition, the potential for resistance to evolve and spread for other cotton herbicides could also 

increase in these areas where growers do not use multiple modes-of-action. The increased use of 

other non-glyphosate alternative herbicides would also be expected.

The DGT cotton system will be an effective alternative to the current Monsanto and academic 

recommended practice for weed control in cotton cultivation and will eliminate the need for the 

application of multiple residual herbicides and reduce the overall number of herbicide applications. 

The new use of dicamba in cotton will displace some of the currently used alternate herbicides 

because the DGT cotton system will provide benefits to the cotton farmer that current weed control 

options do not have, such as:

 Providing improved postemergent weed control and added residual efficacy relative to other 

commercially available herbicides to control tough broadleaf weeds and weeds that are 

resistant to glyphosate and other herbicides used in cotton114

 Increased convenience and flexibility

 An effective weed management system to control and reduce the spread of herbicide-resistant 

weeds

 Increased crop safety relative to other herbicide options

 Remove concerns about plant-back and crop rotation due to long residuals

 Eliminate the need for complex application techniques such as soil incorporation

 Eliminate the need for escape management using directed sprays with a hooded applicator

 Reduced handling restrictions

 A more favorable toxicity profile and lower risk potential to applicators, consumers, and the 

environment compared to alternate herbicides

Dicamba use in combination with glyphosate and glufosinate in cotton that is tolerant of all three 

herbicides offers an attractive opportunity for cotton farmers to preserve the risk benefits that 

glyphosate offers while addressing the problem of glyphosate-resistant weeds. Dicamba’s risk 

profile offers key improvements relative to the alternative cotton herbicide a.i.’s. In the following 

section, a comparative analysis of dicamba to the alternative cotton herbicide a.i.’s is presented. 

Table C-8 lists the most-widely used cotton herbicide products. Table C-9 lists further 

information about the herbicidal a.i.’s used in cotton, such as the registration date, registration 

review status, RED date, where the tolerance information can be found, whether it is a reduced 

 

114 Johnson, B., B. Young, J. Matthews, P. Marquardt, C. Slack, K. Bradley, A. York, S. Culpepper, A. Hager, K. Al-Khatib, L. Steckel, 

M. Moechnig, M. Loux, M. Bernards and R. Smeda. 2010. Weed control in dicamba-resistant cottons. Plant Management 

Network, St. Paul, Minnesota. http://www.plantmanagementnetwork.org/sub/cm/research/2010/dicamba/
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 647 of 946

risk pesticide, and whether it is a restricted use pesticide. Tables C-8 and C-9 are the same as 

Tables A-47 and A-48 in Appendix A.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 648 of 946

Table C-8. Dicamba and Alternative Registered Cotton Herbicides

Representative 

Brand

(EPA Reg. No.)

Active 

Ingredient

2010 use area 

3

For a.i.

(K acres / %) 

Signal 

Word

Content Re-entry

Interval

(REI)

Max. 

Cotton 

lb/a 

(single 

applicati

on)

Max. 

Cotton 

lb/a 

(season)

Label Warnings or Special Directions

Clarity (7969-137) Dicamba 855 / 1.8 Caution 4.0 lb a.e./gal 24 hr 1.0 1 2.0 1 Known to leach; 50-foot buffer to wells; 

Runoff advisory; Drift advisory; Statespecific limitations; Soil type limitations; 

Maximum crop rotation interval 3 – 6 

months.

Ignite (264-829) Glufosinate 

ammonium

1,297 / 2.8 Warning 2.34 lb/gal 12 hr 0.79 1.59 Toxic to vascular plants; May have runoff 

potential; Drift advisory; 70-day cotton 

PHI; Little or no activity in soil; Not in 

Hawaii or S. Florida.

Roundup 

WeatherMAX 

(524-537) 

Glyphosate 23,345 / 50.4 Caution 4.5 lb a.e./gal 4 hr 3.71 5.96 Weed resistance advisory; Drift advisory; 

7-day cotton PHI.

Treflan HFP 

(62719-250)

Trifluralin 4,098 / 8.8 Caution 4.0 lb/gal 12 hr 2 2 Extremely toxic to freshwater, estuarine, 

and marine fish and invertebrates; Some 

crops have long rotational interval (18 - 20 

mos.); 90-day cotton PHI.

Direx 4L (352-678) Diuron 2,110 / 4.6 Caution 4 lb/gal 12 hr 1.6 2.2 Drift Advisory; Crop rotation intervals of 

12 months common; State-specific 

limitations; Soil type limitations; Do not 

feed treated foliage to livestock.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 649 of 946

Table C-8 (continued). Dicamba and Alternative Registered Cotton Herbicides

Prowl 3.3 EC Pendimethali

n

2,010 / 4.3 Caution 3.3 lb/gal 24 hr 2 2 Toxic to fish; Endangered plant species 

buffer required; Drift and runoff may be 

hazardous to aquatic organisms; Long (14 -

24 mos) crop rotation intervals for some 

crops; 60-day cotton PHI; State-specific 

limitation; Soil-type limitations; Do not 

feed treated foliage to livestock.

Valor SX (59639-

99) 

Flumioxazin 1,835 / 4.0 Caution 0.51 lb/lb 12 hr 0.06 0.13 Toxic to non-target plants & aquatic 

invertebrates; Runoff advisory; 40-foot 

aerial buffer to adjacent crops or water 

bodies; 12-month rotation interval 

common; Cotton injury possible; Do not 

feed treated foliage to livestock; 60-day 

cotton PHI.

Staple (352-576) Pyrithiobacsodium1,689 / 3.6 Warning 0.85 lb/lb 24 hr 0.1 0.13 Highly toxic to non-target plants; Drift 

warnings; Cotton injury possible; Weed 

resistance advisory; 60-day cotton PHI; 

State-specific limitations (Staple LX); 10 –

12 month rotation intervals.

Staple LX (352-

613)

PyrithiobacsodiumCaution 3.2 lb/gal 4 hr 0.1 0.13

Dual Magnum 

(100-816)

SMetolachlor1,492 / 3.2 Caution 7.62 lb/gal 24 hr 1.27 2.48 Potential to leach; Potential for runoff; 

Ground & surface water advisory; State 

specific limitations; Soil type limitations; 

Swath adjustment 300 - 400 ft to avoid 

non-target plant injury; 80- to 100-day 

cotton PHI; Do not feed treated foliage to 

livestock.

MSMA 6 Plus 

(19713-42) 

Monosodium 

Metharsonate

1,451 / 3.1 Caution 6 lb/gal 12 hr 1.88 3.75 50-foot buffer around all permanent water 

bodies; Drift warning about adjacent crops 

and sensitive areas; State specific 

limitations; No preplant cotton treatment; 

Do not feed treated foliage to livestock.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 650 of 946

Table C-8 (continued). Dicamba and Alternative Registered Cotton Herbicides

Barage HF (5905-

529)

2,4-D 

Ethylhexyl 

Ester (EHE)

1.421 / 3.1 Caution 4.7 lb a.e./gal 12 hr 2.35 2 4.7 2 Toxic to aquatic invertebrates; Drift may 

adversely affect non-target plants or 

invertebrates; Groundwater advisory; 

Weed resistant biotypes known; Do not 

spray if wind above 15 mph.

Weedar 64 (71368-

1)

2,4-D 

Dimethylami

ne Salt 

(DMA)

[see 2,4-D 

total above]

Danger 3.8 lb a.e./gal 48 hr 1.9 2 3.8 2 May be toxic to fish & aquatic invert; May 

result in groundwater contamination; Drift 

warning; Do not apply if wind above 15 

mph; Apply only when sensitive areas or 

plants are not with 250 feet downwind.

Reflex (100-993) Fomesafensodium1,415 / 3.1 Danger 2.0 lb a.e./gal 24hr 0.375 0.375 May leach; Groundwater advisory; Some 

long rotation intervals (up to 18 mos.); 

Cotton injury warning; Weed resistance 

advisory; State-specific limitations; Soil 

type limitations; 70-day cotton PHI

Gramoxone Inteon 

(100-1217)

Paraquat 1,078 / 2.3 Danger 2.0 lb 

cation/gal

12 hr 1 3 Restricted Use Pesticide due to acute 

toxicity; May be fatal if swallowed or 

inhaled; Toxic to wildlife; Damage / 

toxicity to non-target crops / plants; Drift 

advisory; Cotton injury possible; Do not 

feed treated foliage to livestock; 3-day 

cotton PHI.

Cotoran (66622-

181)

Fluometuron 786 / 1.8 Caution 4 lb/gal 24 hr 2 3 Known to leach; May result in 

groundwater contamination; Weed 

resistance advisory; Avoid drift to sensitive 

areas; 12-month rotation interval for many 

crops; State-specific limitations; Soil type 

limitations; Do not feed treated foliage to 

livestock; 60-day cotton PHI.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 651 of 946

Table C-8 (continued). Dicamba and Alternative Registered Cotton Herbicides

Caparol 4L (100-

620)

Prometryn 867 / 1.9 Caution 4 lb/gal 24 hr 2.4 6 Drift and runoff may be hazardous to 

aquatic organisms; 400 ft upwind swath 

adjustment for sensitive plants; Weed 

resistance advisory; Crop injury possible; 

Soil type limitations; State-specific 

limitations; Do not feed treated foliage to 

livestock.

Envoke (100-1132) Trifloxysulfur

on-sodium

423 / 0.9 Caution 0.75 lb / lb 12 0.012 0.019 Toxic to vascular plants; Ground water 

advisory; Weed resistance advisory; Long 

rotational intervals (12 -22 mos, some 

zones); 60-day cotton PHI; 25-foot buffer 

around treated areas recommended; State 

specific limitations; Soil type limitations.

Aim EW (279-

3242)

carfentrazone 

ethyl

89/0.16 Caution 1.9 lb/gal 12 hr 0.025 0.124 Carfentrazone-ethyl is very toxic to algae 

and moderately toxic to fish. Do not allow 

spray solution to contact cotton foliage, 

green stem tissue, or blooms.

Resolve DF (352-

556)

rimsulfuron 11/0.02 Caution granule 4 hr Not 

labeled 

for 

Cotton

0.03 Do not apply preemergence to coarse 

textured soils (sand, loamy sand, or sandy 

loam) with less than 1% organic matter. 

Adequate soil moisture is required for 

optimum activity. Long rotational 

restrictions up to 10 months. Crop injury 

may occur following application if there is 

prolonged cold weather and/or wet soils.

Treaty (71368-74) thifensulfuro

n methyl

81/0.15 Warning granule 12 hr 0.02 Pre-plant 

burn down 

in 

cotton

Causes substantial but temporary eye 

injury. Do not get in eyes or on clothing. 

Do not graze or feed forage or hay from 

treated areas to livestock. Weed control 

may be reduced if rainfall or snowfall 

occurs soon after application. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 652 of 946

Table C-8 (continued). Dicamba and Alternative Registered Cotton Herbicides

Victory (71368-75) tribenuron 

methyl

70/0.13 Caution granule 12 hr 0.0125 Pre-plant 

burn down 

in 

cotton

Weed control in areas of thin crop stand or 

seedling skips may not be satisfactory. 

Weed control may be reduced if rainfall or

snowfall occurs soon after application. Do 

not apply later than 14 days before planting 

cotton. Do not graze or feed associated by 

products for 60 days after application.

ET Herbicide 

(71711-7

Pyraflufen 

ethyl

56/0.1 Danger 0.208 lb/gal 12 hr 0.003 0.013 This pesticide is toxic to fish and aquatic 

invertebrates. Allow a minimum of 30 

days between applications for use on 

cotton. Apply to cotton having less than 3 

inches of stem bark using hooded ground 

equipment only. Avoid contact with 

desirable vegetation.

Goal 2XL (62719-

424)

oxyfluorfen 190/0.34 Warning 2 lb/gal 24 hr 0.5 1 This product is toxic to aquatic 

invertebrates and wildlife. Do not graze or 

harvest plants from treated areas for feed 

or forage. Treated soil must be thoroughly 

mixed to a depth of 4 inches after harvest 

prior to planting a rotational crop. Care 

must be taken to avoid spray contact with 

cotton leaves. Do not apply to cotton less 

than 6 inches tall or severe crop injury will 

result.

Resource (59639-

82)

flumiclorac 

pentyl ester

15/0.03 Warning 0.86 lb/gal 12 hr 0.05 0.094 Causes substantial but temporary eye 

injury. This product is toxic to shrimp. 

Keep out of lakes, ponds, and streams. Do 

not graze animals on green forage or use as 

feed fewer than 28 days after application.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 653 of 946

Table C-8 (continued). Dicamba and Alternative Registered Cotton Herbicides

1 Dicamba rates cited are those proposed for use on DGT cotton.

2 2,4-D products are not labeled for cotton treatments. Preplant treatments, more than 29 days before planting, are used for burndown weed control using the 

Fallow portion of the label. 

3 Monsanto private market survey data. The data shown are for the cotton acres to which the relevant active ingredient was applied in 2010, and the percentage 

of total treated acres this constitutes. A treated acre is application of one active ingredient once. Multiple active ingredients or multiple applications results in 

total treated acres that exceed total planted cotton acres. No entry is shown for products containing more than one active ingredient, since these acres are 

counted in the single active ingredient rows.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 654 of 946

Table C-9. Dicamba Compared to Active Ingredients Contained in Alternative Herbicide Products

Active Ingredient First 

Registered

Registration 

Review

Status 1

RED 

Date

Max. Cotton lb/a 

(single 

application) 2

Max. Cotton 

lb/a (season) 

2

Tolerances 

40 CFR 180.

EPA Reduced 

Risk

Classification

Restricted 

Use

dicamba-diglycolamine salt 2-Feb-56 unsched. 2006 1.03 2.03 227 N N

Glufosinate-ammonium

Glufosinateammonium

29-May-91 2008 N/A 0.79 1.59 473 Yes

Glyphosate (salts)

Glyphosate 

(salts)

7-Sept-88 2009 09/23/2009 3.71 5.96 364 Yes

Herbicide a.i.s Applied Primarily at a PE Timing

2,4-D EHE (esters)4

3-Jun-52 2013 2005

2.0 5 4.0 5

142 N N

2,4-D DMA (salts)

4 2.0 5 4.0 5

flumiclorac pentyl 23-Mar-94 2009 N/A 0.05 0.094 477 Yes No

S-metolachlor 18-May-83 2016 12/01/19

94

1.27 2.48 368 Yes No

oxyfluorfen 17-May-79 2015 10/01/20

02

0.5 1 381 No No

pyraflufen ethyl 27-Sept-02 2014 N/A 0.003 0.013 585 No No

rimsulfuron 20-Sept-89 2012 N/A Not labeled for cotton 0.03 478 No No

thifensulfuron methyl 25-Apr-86 2011 N/A 0.02 N/A 439 No No

tribenuron methyl 22-May-89 2011 N/A 0.0125 N/A 451 No No

Herbicide a.i.s Applied at both PE and POE Timings

carfentrazone ethyl 02-Aug-95 2011 N/A 0.025 0.124 515 Yes No

fluometuron 28-May-74 Unsched. 09/28/20

05

229 No No

fomesafen sodium 10-Apr-87 2007 N/A 0.375 0.375 433 No No

paraquat dichloride 08-Jan-80 2011 08/01/19

97

1 3 205 No Yes

Prometryn 19-Aug-74 2013 1996 2.4 5.95 222 N N

Pyrithiobac-Sodium 29-Jun-95 docket ‘11 NA 0.1 0.13 487 N N
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 655 of 946

Table C-9 (continued). Dicamba Compared to Active Ingredients Contained in Alternative Herbicide Products

Herbicide a.i.s Applied Primarily at a POE Timing

flumioxazin 01-Aug-96 2011 N/A 0.06 0.13 568 No No

MSMA 25-Dec-63 2013 2006 corr 

2009

1.88 3.75 289 N N

pendimethalin 20-Mar-75 2012 04/01/19

97

2 2 361 No No

trifloxysulfuron-sodium 29-Jun-03 2013 NA 0.012 0.019 591 N N

trifluralin 04-Dec-68 2012 09/01/19

95

2 2 207 No No

 1 Registration Review Status: year docket is scheduled to open, unless unscheduled. FWP = Final Work Plan stage. If docket is open, “docket XX” = year 

opened.

 2 Rates for dicamba, 2,4-D, fomesafen, and glyphosate are expressed as acid equivalents. All others are on an a.i. basis, as stated, except paraquat is on a cation 

basis. Regional or soil type limitations may lower this rate.

 3 Maximum treatment rates for the proposed dicamba label on DGT cotton.

 4 For the 2,4-D ester group, the ethylhexyl ester (EHE) is taken as representative. For the salt group, the dimethylamine (DMA) salt is taken as representative.

 5 Rates taken from Master 2,4-D Label (http://www.24d.org/masterlabel/default.aspx) for Fallow application. There are no specific cotton treatment 

directions. Fallow application must precede planting by 29 days or more.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 656 of 946

C.5. Comparative Analysis for Water Impacts

The intent of this comparative analysis is to define current herbicide use in U.S. soybean and cotton 

production, and to compare dicamba’s potential impacts on water, soil and air to herbicides currently 

used by growers for weed control. In order for a pesticide (e.g., dicamba herbicide) to be registered 

by U.S. EPA it must meet the FIFRA and FFDCA standards for safety to human health and the 

environment. The U.S. EPA must conclude that the herbicide when used according to the label does 

not pose an unreasonable risk to humans or the environment. Therefore, all alternative herbicides 

used in soybean and cotton production can be used safely, and do not pose an unreasonable risk to 

humans or the environment. Nonetheless, in some instances dicamba offers a reduction in risk 

potential (i.e., hazard) compared to some alternative herbicides in the same risk category (e.g., aquatic 

plant risk). In other instances dicamba presents a similar risk potential compared to some 

alternatives, and in some instances, dicamba presents a greater risk potential compared to some 

alternatives. This serves to demonstrate that with respect to potential impacts/risk to human health 

and the environment dicamba does not pose any appreciable difference to the human environment. 

C.5.1. Soybean Analysis

C.5.1.1. Groundwater Comparison

Table C-10 provides information about the soil leaching potential of dicamba and the twenty-two 

alternative herbicide a.i.’s used in cotton. The two aspects of this evaluation are: (1) the properties of 

each substance indicating that it may likely move downward through the soil layers and contaminate 

groundwater; and (2) estimated groundwater concentrations at a level that could potentially represent 

a toxicity concern.

Herbicide physico-chemical properties that are associated with downward soil mobility have been 

widely investigated. Persistence in soil (slow degradation) and weak soil binding are common 

predictors of leachability risk. The Groundwater Ubiquity Score (GUS) is an empirical index that 

mathematically combines these two parameters to sort chemicals into categories ranging from 

“extremely low” likelihood of leaching to “very high” likelihood (Gustafson 1989).115 Table C-10 lists 

information about: 

 

115 GUS is calculated as GUS = LOG10(soil half-life)*(4-LOG10(Koc)). The interpretation of GUS as a measure of the likelihood of 

leaching is as follows: < 0.1 = Extremely Low (EL); 0.1 – 1.0 = Very Low (VL); 1.1 – 2.0 = Low (L); 2.1 – 3.0 = Moderate (M); 3.1 –

4.0 = High (H); > 4.0 = Very High (VH).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 657 of 946

 Soil degradation rate (soil half-life), which quantifies the time for 50% of the initial amount to 

dissipate. The typical values were obtained from the IUPAC Footprint database.116

 Soil mobility constant with regard to organic carbon (Koc), which is the equilibrium 

concentration ratio between soil and pore water, normalized for the organic carbon content 

of the soil. Typical values were obtained from the IUPAC Footprint database.117 

 The GUS index, calculated by the published mathematical formula, using the typical soil halflife and typical Koc values, along with the interpretive category.

 The maximum single application rate in both pounds per acre and in kilograms per hectare 

for dicamba and each alternative herbicide a.i. Potential groundwater concentrations are 

directly related to application rate.

 The IUPAC Footprint database provides a standard estimate of groundwater concentration 

using EPA’s SCI-GROW model and assumes a consistent 1.0 kilogram per hectare 

application. Because these estimates have been calculated in the same way for dicamba and 

the alternative herbicide a.i.’s, they serve as a basis for comparison of leachability.

 The IUPAC Footprint SCI-GROW estimates were adjusted to reflect the labeled maximum 

application rate in cotton by multiplication of the application rate in kilograms per hectare.

 In a dietary risk assessment, EPA assumes that a 10 kilogram child consumes 1 liter of water 

per day. Using this standard, the SCI-GROW-estimated groundwater concentrations due to 

the maximum cotton application rate were converted to the potential exposure to a child 

arising from drinking such groundwater, in milligrams of a.i. per kilogram of body weight per 

day. This calculation provides a way to compare potential groundwater concentration to 

toxicity thresholds. The child’s water consumption was chosen over that of an adult because 

children’s waterborne exposure is greater than that of an adult on a body weight basis, so it 

represents a worst-case assessment.

 The chronic Population Adjusted Dose from EPA is shown for comparison.

 The child’s potential exposure to dicamba and each alternative herbicide a.i. via drinking 

groundwater expressed as a percentage of the cPAD. 

Dicamba’s SCI-GROW-estimated groundwater concentration (0.033 μg/L) is very small, particularly 

in relationship to dicamba’s chronic toxicity reference point (cPAD). Table C-10 shows that a child’s 

potential drinking water exposure to dicamba is calculated to be 0.0008% of the cPAD, where the 

cPAD is considered to be the highest safe chronic exposure level. Dicamba’s estimated child 

exposure level is the 6th lowest among the twenty-two potential alternative a.i.’s for which such a 

value could be calculated in this analysis; data were not available for MSMA (see below). For some 

alternative herbicide a.i.’s, the child’s potential drinking water exposure as a percentage of the 

respective cPAD was calculated to be 100- to 1000-fold higher than that of dicamba. 

Two criteria were evaluated to determine a Groundwater Risk Score as shown in Table C-10. The 

first criterion was the GUS groundwater vulnerability index, indicating whether the a.i.’s physico-

 

116 The Footprint database, as presented by IUPAC at http://sitem.herts.ac.uk/aeru/iupac/index.htm

117 Values from the Footprint database were not confirmed by comparison to values in U.S. registration documents such as REDs.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 658 of 946

chemical properties predict downward soil mobility. GUS values above 3.0 are rated as high or very 

high leachability potential, which was chosen as one trigger for groundwater risk. A second criterion 

was the percentage of the cPAD potentially experienced by a child consuming the SCI-GROWestimated groundwater concentration of each a.i. The % exposure above 0.1% of the cPAD was 

chosen as a second trigger for groundwater risk. A.i.’s that met both triggers, i.e., a high or very high 

GUS index and exposures > 0.1% of cPAD, were scored with a Black Circle. An a.i. that met just 

one of these two triggers was scored with a Half Circle. Those a.i.’s that met neither trigger are 

indicated in Table C-10 with a White Circle. 

Monsanto believes that for groundwater risk, dicamba offers lower potential risk compared to 

thirteen of the alternative herbicide a.i.’s which were shown to have Black Circle or Half Circle 

scores.118 The dietary exposure and groundwater contamination risk could be considered relatively 

greater for MSMA and fluometuron as compared to dicamba, therefore justifying their categorization 

as higher groundwater risk with Black Circle Groundwater Risk scores. Seven alternative herbicide 

a.i.’s have low Groundwater Risk Scores and are marked with White Circles.

 

118 As discussed in section A.3.7.2.2, all alternative herbicides used in soybean production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 659 of 946

Table C-10. Groundwater and Leaching Parameters for Dicamba and Alternate Active Ingredients

Active Ingredient

Typical 

Soil 

Halflife1

Soil 

Mobility

Koc1

GUS 

Leaching 

Index3 

(Interpre

tation) 2

Maximum 

Cotton 

lb/acre 

(single 

treatment)

3

Maximum 

Cotton 

kg/ha 

(single 

treatment)

3

SCIGROW 

Conc. Est. 

@ 1 

kg/ha 1

SCIGROW 

Conc. Est. 

@ cotton 

Max Rate 

4

Child 

(10 kg) 

consum

ption 

(1L/day)

5

cPAD 

mg/kg/

day 6

Child's 

water 

exposure 

as % 

cPAD 7

Groundwater 

and Leaching 

Score 8 

days (calc) lb/acre kg/ha μg/L μg/L mg/kg

dicamba acid /DGA salt 8 13.4 2.6 (M) 1 1.1 0.0326 0.03586 3.59E-06 0.45 0.0008

glufosinate-ammonium 7.4 600 1.1 (L) 0.79 0.89 0.00982 0.00874 8.74E-07 0.006 0.01457 *

glyphosate (salts) 1 0 1435 0.9 (VL) 2 4.2 0.00535 0.02247 2.25E-06 1.75 0.00013 *

2,4-D DMA (salts) 2.5 2.1 (M) 0.0248 0.05555 5.56E-06 0.005 0.1111

2,4-D EHE (esters) 6 4 1.62 0.0248 0.05555 5.56E-06 0.005 0.1111

flumiclorac pentyl 8 6 3 0 1 (EL) 0.054 0.06048 0.0025 0.00015 1.51E-08 1 1.5E-06

S-metolachlor 9 0 120 1.9 (L) 1.31 1.4672 0.051 0.07483 7.48E-06 0.1 0.00748

oxyfluorfen 4 100,000 0.19 (EL) 0.5 0.56 0.00658 0.00368 3.68E-07 0.03 0.00123

pyraflufen ethyl 4 1949 0.43 (EL) 0.0053 0.005936 0.0023 1.3E-05 1.35E-09 0.2 6.7E-07

rimsulfuron 1 4 50.3 3.23 (H) 0.03 0.0336 0.317 0.01065 1.07E-06 0.118 0.0009

thifensulfuron methyl 4 28.3 1.53 (L) 0.047 0.05264 0.00351 0.00018 1.85E-08 0.043 4.3E-05

tribenuron methyl 0.5 3 5 2.88 (M) 0.047 0.05264 0.135 0.00711 7.11E-07 0.008 0.00888

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

carfentrazone ethyl 1 5 866 0.32 (EL) 0.031 0.03472 5.9E-05 2.1E-06 2.06E-10 0.03 6.9E-07

fluometuron 3 5 175 3.9 (H) 2 2.24 1.04 2.3296 2.33E-04 0.006 4.23564

fomesafen sodium 1067 5 0 4.4 (VH) 0.38 0.4256 0.408 0.17364 1.74E-05 0.003 0.69458

paraquat dichloride 24.3 100000 -0.6 (EL) 1 1.12 0.00535 0.00599 5.99E-07 0.005 0.01332

prometryn 4 9 400 2.3 (M) 2.4 2.688 0.0113 0.03037 3.04E-06 0.04 0.00759

Pyrithiobac-sodium 181 9 5.4 (VH) 0.1 0.112 5.49 0.61488 6.15E-05 0.58 0.0106

Herbicide A.I.s with Potential Displacement of Postemergent Acres

flumioxazin 200 889 1.4 (L) 0.06 0.0672 0.029 0.00195 1.95E-07 0.02 0.00097

MSMA 4 1 - 2.3 (M) 1.88 2.1056 - - - 0.03 -

pendimethalin 6 0 17581 -0.5 (EL) 1.98 2.2176 0.00535 0.01186 1.19E-06 0.03 0.00395

Trifloxysulfuron-sodium 63.5 306 5.6 (VH) 0.012 0.01344 0.216 0.0029 2.90E-07 0.237 0.00012

trifluralin 181 15800 -0.4 (EL) 2 2.24 0.00613 0.01373 1.37E-06 0.024 0.00572

Herbicide A.I.s with Potential Displacement of Preemergent Acres

88.4 2 2.24
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1 Parameters obtained from the Footprint database, as presented by IUPAC http://sitem.herts.ac.uk/aeru/iupac/index.htm or http://pmep.cce.cornell.edu/profiles/extoxnet/index.html

2 Gustafson DI (1989): Groundwater ubiquity score: A simple method for assessing pesticide leachability. Environ Toxicol. Chem. 8, 339–357. GUS is calculated as GUS = LOG10(soil halflife)*(4-LOG10(Koc)). The interpretation of GUS as a measure of the likelihood of leaching is as follows: < 0.1 = Extremely Low (EL); 0.1 – 1.0 = Very Low (VL); 1.1 – 2.0 = Low (L); 

2.1 – 3.0 = Moderate (M); 3.1 – 4.0 = High (H); > 4.0 = Very High (VH).

3 Maximum labeled single application rate to cotton. This rate was converted to kg/hectare (ha) units using: 1 lb = 0.454 kg and 1 acre = 0.405 ha.

4 The Footprint database, as presented by IUPAC http://sitem.herts.ac.uk/aeru/iupac/index.htm, provides a SCI-GROW concentration estimate for groundwater based on the a.i.s 

chemical properties using a consistent set of assumptions, including a 1 kg/ha application. This was converted to a concentration estimate by multiplying by the maximum single cotton 

application rate in kg/ha.

5 Using standard EPA assumptions for a child’s water consumption and weight (1 liter per day, 10 kg body weight), the groundwater concentration estimate was converted to a daily exposure 

estimate.

6 The chronic population adjusted dose (cPAD) as determined by EPA risk assessments. 

7 The child’s daily exposure estimate was compared to the chronic population adjusted dose (cPAD) as determined for the a.i. by EPA, and expressed as a percentage.

8 The Groundwater and Leaching score is determined by combining two criteria listed in Table C-10. A GUS groundwater vulnerability index that is rated high (H) or very high (VH) 

constitutes one criterion. When the Child's water exposure is greater than 0.001 that constitutes a second criterion. When both criteria are exceeded, the a.i. is marked with a Black Circle. 

When only one is exceeded, the a.i. is marked with a half Circle. Exceedance of neither criterion earns a White Circle.

* Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated pest management system.
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C.5.1.2. Surface water and ecological effects on aquatic organisms

C.5.1.2.1. Fish and Aquatic Invertebrates

Table C-11 provides information about the hazards, exposures, and risks of dicamba and each of the 

eighteen alternative herbicides to fish and aquatic invertebrates (considering 2,4-D acid, salts, and 

esters as one alternative herbicide). The listed parameters include:

 LC50 endpoints from acute fish toxicity studies, as reported in EPA’s ecotoxicity database119, 

published in a RED or in Registration Review risk assessments. The highest and lowest 

available LC50 values for any fish study are listed, regardless of species, including both fresh 

and marine species together. The purpose is to define a range of concentrations that spans 

the expected fish toxicity levels.

 EC50 endpoints from acute aquatic invertebrate studies, as reported from the same sources 

cited above. The highest and lowest available EC50 values for any invertebrate study are 

listed, regardless of species, including both fresh and marine species together. The purpose 

is to define a range of concentrations that spans the expected aquatic invertebrate-toxic 

levels.

 Estimated environmental exposure concentrations (EECs) in surface water for each of the 

eighteen alternative herbicides. The third column in Table C-11, identified as “Calculated 

EEC”, provides a simple standard estimate based on the maximum single application rate in 

soybean, using EPA’s standard field-farm pond scenario. This scenario examines a 1-acre 

pond in a 10-acre field in which (1) 5% of the application drifts into the 6-foot-deep pond 

and (2) 5% of the application onto the 10 acres runs off into the same pond. The fourth 

column in Table C-11 lists other model estimates of surface water concentrations as 

provided by one or more modeling programs, as cited by EPA in public documents, such as 

Federal Register final tolerance rule drinking water assessments. The purpose is to define a 

range of concentrations that spans available estimates of potential aquatic exposure levels.

 Calculated Risk Quotients (RQs) for aquatic animals, comprised of fish and aquatic 

invertebrates combined together. Rather than calculate a single RQ for each species, 

Monsanto has calculated a range of potential RQs for each herbicide, bracketed by the bestand worst-case values. The “best” RQ is derived from the ratio of the lowest reported EEC 

concentration divided by the highest LC50 or EC50 for any aquatic animal. Conversely, the 

“worst” RQ is derived from the ratio of the highest EEC concentration divided by the 

lowest LC50 or EC50 for any aquatic animal. (Note: the RQ figures are rounded to two 

decimal places, so that entries that appear as “0.00” mean that the specific RQ is less than 

0.005.) The purpose is to define a range of RQs that span and describe the risk posed by the 

alternative herbicide to aquatic animals. The RQs that exceed the EPA’s Level of Concern 

(LOC) of 0.5 are marked in bold font.

Using the worst-case risk quotient, ten of 18 alternative herbicides have risk quotients greater than 

or equal to 0.01, while the worst-case risk quotient for dicamba and seven other herbicides is <0.01. 

 

119 National Information System – Regional IPM Centers. OPP Pesticide Ecotoxicity Database. 

http://www.ipmcenters.org/Ecotox/index.cfm [Accessed May 27, 2010].
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Only three of these 10 herbicides have risk quotients greater than 0.05 or 0.1, the levels of concern 

for threatened or endangered species and acute restricted use, respectively. Two of these 10 

herbicides have RQ values greater than 0.5, the highest acceptable level of concern. Monsanto 

believes that based on risk quotients, dicamba offers a lower risk to aquatic animals relative to at 

least three of the 18 alternative herbicides: 2,4-D esters, flumioxazin, and lactofen. This conclusion 

is tabulated in Table C-6, which summarizes the comparative analysis of dicamba and alternative 

herbicides.
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Table C-11. Aquatic Toxicity Parameters for Fish and Aquatic Invertebrates for Alternative Herbicides

Active Ingredient

Maximum 

Soybean 

lb/acre 

(single 

treatment)1

Calculated 

EEC 

(ppm) 2,3

FIRST, GENEEC 

or PRZX/EXAMS 

Surface Water ppm 

(RED or Tolerance 

Rule)4

Fish LC50 Range 

(ppm)5

Aquatic Invertebrate 

LC50 or EC50 Range 

(ppm)f

Risk Quotient for 

Aquatic Animals 

Range6

Label 

Warnings7

low high low high best worst

glyphosate salts 1.5 0.050 0.0008 - 0.021 45 >1000 55 780 0.00 0.00

dicamba /DGA salt 1 0.034 0.01 - 0.036 28 > 270 >100 >270 0.00 0.00

2,4-D acid + salts 0.93 0.031 0.064 - 0.118 >80 2244 25 820 0.00 0.00

2,4-D esters 0.93 0.031 0.064 - 0.118 >0.15 14.5 2.2 12 0.00 < 0.79

flumioxazin 0.096 0.003 0.018 - 0.034 2.3 21 0.23 5.5 0.00 0.15

"toxic to 

invertebrates”

imazethapyr 0.064 0.002 0.006 > 112 423 > 109 > 1000 0.00 0.00

cloransulam-methyl 0.04 0.001 0.002 > 86 > 154 > 111 > 121 0.00 0.00

"toxic to 

invertebrates”

chlorimuron-ethyl 0.14 0.005 0.003 - 0.005 > 2 8.4 >10a > 10 0.00 0.00

fomesafen 0.375 0.013 0.006 - 0.012 126 > 163 25 376 0.00 0.00

flumiclorac-pentyl 0.081 0.003 0.00024 >0.189 > 24 >0.189 >38 0.00 0.02

"toxic to 

shrimp"

sulfentrazone 0.31 0.010 0.004 - 0.016 94 > 120 1 60.4 0.00 0.02

"toxic to 

invertebrates”

thifensulfuron 0.013 0.000 0.0003 - 0.004 >100 > 100 >1000 > 1000 0.00 0.00
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Table C-11 (continued). Aquatic Toxicity Parameters for Fish and Aquatic Invertebrates for Alternative Herbicides

Active Ingredient

Maximum 

Soybean 

lb/acre 

(single 

treatment)1

Calculated 

EEC 

(ppm) 2,3

FIRST, GENEEC 

or PRZX/EXAMS 

Surface Water ppm 

(RED or Tolerance 

Rule)4

Fish LC50 Range 

(ppm)5

Aquatic 

Invertebrate LC50 or 

EC50 Range (ppm)5

Risk Quotient for 

Aquatic Animals 

Range6

Label 

Warnings7

low high low high best worst

imazaquin 0.123 0.004 0.004 - 0.008 280 420 280a 280 0.00 0.00

imazamox-ammonium 0.04 0.001 0.002 > 94.2 > 122 >94.3 > 122 0.00 0.00

paraquat dichloride 1.0 0.033 0.0015 > 1 156 1.2 1.2 0.00 < 0.05

lactofen 0.3 0.011 0.000008 - 0.4 0.46 0.46 0.02 4.85 0.00 20 "toxic to fish"

glufosinateammonium 0.66 0.022 0.043 - 0.094 > 320 > 1000 8 668 0.00 0.01

2,4-DB 0.4 0.013 0.013 - 0.015 2 18 25a 25 0.00 0.01 "toxic to fish"

fluthiacet-methyl 0.0065 0.000 0.0005 - 0.0008 0.043 0.16 0.3 >2.3 0.00 0.02

acifluorfen sodium 0.374 0.013 0.0024 - 0.010 31 204 28.1 > 1000 0.00 0.00

mesotrione 0.1875 0.011 0.004 - 0.02 > 114 520 3.3 840 0.00 0.01

1The highest single-treatment rate permitted by the herbicide’s product labels. This rate is used to calculate potential acute exposure to aquatic non-target species via 

spray drift or runoff.

2Based on the maximum single treatment rate, with 5% spray drift and 5% runoff from 10 treated acres into a 1-acre 6-foot-deep pond.

3The Estimated Environmental Concentration in surface water. It was calculated by Monsanto using the EPA’s “standard field-farm pond scenario” 

http://www.epa.gov/oppefed1/models/water/geneec2_description.htm. In this scenario, it is assumed that the herbicide is applied to a 10 acre farm field containing 

a 1 acre pond that is six feet deep. The pond experiences 5% of the application rate by spray drift and 5% of the application on the soil enters the pond via runoff. 

This concentration estimation is a simple, conservative Tier 1 procedure that utilizes only the application rate to estimate aquatic exposures, and allows quick 

comparison of many different herbicides. Other more increasingly-detailed computer models can be used to obtain more refined EEC estimates, but these require the 

user to input various physical chemical parameters and weather data for each product to be modeled. Examples of these methods are listed in the next column.

4Modeling estimates of potential aquatic exposure levels. When EPA conducts risk assessments, it uses computer models to obtain estimates of potential surface water 

concentrations. These are published in the RED for each herbicide, or in tolerance rules in the Federal Register. The range of estimates is listed, which can be 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 665 of 946

compared to the single number in the prior column. Sources of these estimates are listed in the “ALTERNATIVE HERBICIDE-SPECIFIC REFERENCES” 

section.

5“Fish LC50 Range (ppm)” and “Aquatic Invertebrate LC50 or EC50 Range (ppm)”. These four columns describe the range of hazard data found in public data sources 

representing the toxicity of each herbicide versus freshwater and marine animals. The LC50 or EC50 means the water concentration needed to kill or immobilize half of 

the test species, which is a standard potency descriptor. The highest and lowest values found for any fish species (trout, bluegill, sheepshead, etc.) were tabulated. 

Likewise, the highest and lowest values found for any aquatic invertebrate species (Daphnia, shrimp, crab, etc.) were included. Sources of these data are listed in the 

“ALTERNATIVE HERBICIDE-SPECIFIC REFERENCES” section and in available public databases (National Information System – Regional IPM Centers. OPP 

Pesticide Ecotoxicity Database. http://www.ipmcenters.org/Ecotox/index.cfm).

6EPA’s EFED uses a Risk Quotient (RQ) method for ecological risk assessment. The RQ equals the potential exposure level divided by the hazard level. Higher 

exposures or more potent hazard findings lead to higher RQs. EFED has established Levels of Concern (LOCs) for various non-target species categories. When the 

RQ exceeds the LOC, further refinement is needed to determine whether risk mitigation might be needed. For non-listed aquatic animals, the LOC for acute risk is 

0.5, for acute risk restricted use is 0.1, and for threatened or endangered species it is 0.05. In this analysis, Monsanto calculated best-case RQs by dividing the lowest 

EEC estimate by the highest hazard (LC50 or EC50) value, and calculated the worst-case RQ from the highest EEC and lowest hazard value. The purpose was to 

bracket a range that typified the aquatic animal risk presented by each herbicide. When neither the worst-case nor the best-case RQs exceed a LOC of 0.05, Monsanto 

concluded that risk to aquatic animals is minimal. Instances where the LOC threshold of 0.5 is exceeded are highlighted in bold font.

7Lists instances where the product label includes warning statements about aquatic animal exposure.
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C.5.1.2.2. Aquatic Plants 

Table C-12 provides information about the hazards, exposures, and risks of dicamba and each of the 

eighteen (18) alternative herbicides to aquatic plant species, specifically duckweed and aquatic algae 

species (considering 2,4-D acid, salts, and esters as one alternative herbicide). The data format, 

sources, and methods of Estimated Environmental Exposure Concentration (EEC) calculation are 

identical to those described above for the aquatic animals (Table C-11). A Level of Concern (LOC) 

value of 1.0 has been used for judging RQ exceedances in the case of aquatic plants, consistent with 

EPA EFED’s normal practices.

The assessment and comparison summarized in Table C-12 establishes that dicamba poses little 

acute risk to aquatic plants at use rates of 0.05 – 1.0 lb dicamba a.e./acre, which is consistent with 

EFED’s assessment published in the RED EFED Chapter. Monsanto was unable to identify 

aquatic plant hazard data for three of the alternative herbicides (imazaquin, chlorimuron-ethyl, and 

flumiclorac-pentyl). For nine (9) of the eighteen (18) alternative herbicides, the range of RQs is 

< 0.005 to 0.75; that is, none of these nine a.i.’s present an aquatic plant risk, which even in the 

worst-case calculation, reach EFED’s Level of Concern (LOC) for aquatic plants. However, for 

seven of the alternative herbicides, the worst-case RQs did exceed EFED’s LOC of 1.0. It is not 

surprising that some herbicides are quite toxic to aquatic plants, and the worst-case RQs for three of 

the alternate herbicides (flumioxazin, lactofen, and paraquat dichloride) exceeded the LOC by a 

factor of more than 50-fold.

Monsanto believes that dicamba offers a lower risk to aquatic plants relative to at least seven of the 

18 alternative herbicides (2,4-D, flumioxazin, sulfentrazone, thifenslufuron, paraquat dichloride, 

lactofen, and mesotrione). This conclusion is tabulated in Table C-6, which summarizes the 

comparative analysis of dicamba and alternative herbicides.
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Table C-12. Aquatic Toxicity Parameters for Aquatic Plants for Alternative Herbicides

The first three columns in this table are identical to- those in Table C-11.

1The highest single-treatment rate permitted by the herbicide’s product labels. This rate is used to calculate potential 

acute exposure to aquatic non-target species via spray drift or runoff.

2Based on the maximum single treatment rate, with 5% spray drift and 5% runoff from 10 treated acres into a 1-acre 6-

foot-deep pond.

3The Estimated Environmental Concentration in surface water. It was calculated by Monsanto using the EPA’s 

“standard field-farm pond scenario” http://www.epa.gov/oppefed1/models/water/geneec2_description.htm |Accessed 

May 28, 2010|. In this scenario, it is assumed that the herbicide is applied to a 10 acre farm field containing a 1 acre pond 

that is six feet deep. The pond experiences 5% of the application rate by spray drift and 5% of the application on the soil 

enters the pond via runoff. This concentration estimation is a simple, conservative Tier 1 procedure that utilizes only the 

application rate to estimate aquatic exposures, and allows quick comparison of many different herbicides. Other more 

increasingly-detailed computer models can be used to obtain more refined EEC estimates, but these require the user to 

Active Ingredient

Maximum 

Soybean 

lb/acre 

(single 

treatment)1

Calculated 

EEC 

(ppm) 2,3

FIRST, 

GENEEC or 

PRZX/EXAMS 

Surface Water 

ppm (RED or 

Tolerance Rule)4

Duckweed and 

Algae EC50 Range 

(ppm)5

Risk Quotient for 

Aquatic Plants 

Range6

low high best worst

glyphosate salts 1.5 0.050 0.0008 - 0.021 0.77 38.6 0.00 0.06

dicamba /DGA salt 1 0.034 0.01 - 0.036 0.06 > 3.7 0.00 0.60

2,4-D acid + salts 0.93 0.031 0.064 - 0.118 0.29 156 0.00 0.41

2,4-D esters 0.93 0.031 0.064 - 0.118 0.066 >19.8 0.00 1.79

flumioxazin 0.096 0.003 0.018 - 0.034 0.0005 0.019 0.16 68.00

imazethapyr 0.064 * 0.002 0.006 0.008 59.2 0.00 0.75

cloransulam-methyl 0.04 0.001 0.002 0.003 135 0.00 0.67

chlorimuron-ethyl 0.14 0.005 0.003 - 0.005 NA NA NA NA

fomesafen 0.375 0.013 0.006 - 0.012 0.09 71 0.00 0.14

flumiclorac-pentyl 0.081 0.003 0.00024 NA NA NA NA

sulfentrazone 0.31 0.010 0.004 - 0.016 0.002 0.033 0.12 8.0

thifensulfuron 0.013 0.000 0.0003 - 0.004 0.0016 > 0.026 0.02 2.50

imazaquin 0.123 0.004 0.004 - 0.008 NA NA NA NA

imazamoxammonium

0.04 0.001 0.002 0.011 > 0.038 0.03 0.18

paraquat dichloride 1.0 0.033 0.0015 0.00055 2.84 0.00 90.9

lactofen 0.3 0.011 0.000008 - 0.4 0.001 0.001 0.00 400

glufosinateammonium

0.66 0.022 0.043 - 0.094 1.5 7.8 0.00 0.06

2,4-DB 0.4 0.013 0.013 - 0.015 >0.932 >0.932 <0.01 <0.02

fluthiacet-methyl 0.0065 0.000 0.0005 - 0.0008 0.0022 >0.018 <0.01 0.36

acifluorfen sodium 0.374 0.013 0.0024 - 0.010 > 0.26 0.38 0.01 <0.05

mesotrione 0.1875 0.011 0.004 - 0.02 0.018 132 0.00 1.11
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input various physical chemical parameters and weather data for each product to be modeled. Examples of these methods 

are listed in the next column.

4Modeling estimates of potential aquatic exposure levels. When EPA conducts risk assessments, it uses a computer 

models to obtain estimates of potential surface water concentrations. These are published in the RED for each herbicide, 

or in tolerance rules in the Federal Register. The range of estimates is listed, which can be compared to the single number 

in the prior column. Sources of these estimates are listed in the “ALTERNATIVE HERBICIDE-SPECIFIC 

REFERENCES” section.

5These two columns describe the range of hazard data found in public data sources representing the toxicity of each a.i. 

versus freshwater and marine plants. The EC50 means the water concentration needed to kill or prevent growth of half of 

the test species, which is a standard potency descriptor. The highest and lowest values found for any aquatic plant species 

(diatom, duckweed, alga, etc.) were tabulated. Sources of these data are listed in the “ALTERNATIVE HERBICIDESPECIFIC REFERENCES” section of this document and in available public databases cited in National Information 

System – Regional IPM Centers. OPP Pesticide Ecotoxicity Database. http://www.ipmcenters.org/Ecotox/index.cfm

6As described above for Table C-11, EPA’s EFED uses a Risk Quotient (RQ) method for ecological risk assessment. For 

non-listed aquatic plants or for threatened or endangered species the LOC is 1.0. In this analysis, Monsanto calculated 

best-case RQs by dividing the lowest EEC estimate by the highest hazard (EC50) value, and calculated the worst-case RQ 

from the highest EEC and lowest hazard value. The purpose was to bracket a range that typified the aquatic plant risk 

presented by each herbicide. When neither the worst-case nor the best-case RQs exceed a LOC of 1.0, Monsanto 

concluded that risk to aquatic plants is minimal. Instances where the LOC threshold of 1.0 is exceeded are highlighted in 

bold font.

C.5.2. Cotton Analysis

C.5.2.1. Groundwater Comparison

Table C-10 provides information about the soil leaching potential of dicamba and the twenty-two 

alternative herbicide a.i.’s used in cotton. The two aspects of this evaluation are: (1) the properties of 

each substance indicating that it may likely move downward through the soil layers and contaminate 

groundwater; and (2) estimated groundwater concentrations at a level that could potentially represent 

a toxicity concern.

Herbicide physico-chemical properties that are associated with downward soil mobility have been 

widely investigated. Persistence in soil (slow degradation) and weak soil binding are common 

predictors of leachability risk. The Groundwater Ubiquity Score (GUS) is an empirical index that 

mathematically combines these two parameters to sort chemicals into categories ranging from 

“extremely low” likelihood of leaching to “very high” likelihood (Gustafson 1989).120 Table C-11 lists 

information about: 

 

120 GUS is calculated as GUS = LOG10(soil half-life)*(4-LOG10(Koc)). The interpretation of GUS as a measure of the likelihood of 

leaching is as follows: < 0.1 = Extremely Low (EL); 0.1 – 1.0 = Very Low (VL); 1.1 – 2.0 = Low (L); 2.1 – 3.0 = Moderate (M); 3.1 –

4.0 = High (H); > 4.0 = Very High (VH).
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 Soil degradation rate (soil half-life), which quantifies the time for 50% of the initial amount to 

dissipate. The typical values were obtained from the IUPAC Footprint database.121

 Soil mobility constant with regard to organic carbon (Koc), which is the equilibrium 

concentration ratio between soil and pore water, normalized for the organic carbon content 

of the soil. Typical values were obtained from the IUPAC Footprint database.122 

 The GUS index, calculated by the published mathematical formula, using the typical soil halflife and typical Koc values, along with the interpretive category.

 The maximum single application rate in both pounds per acre and in kilograms per hectare 

for dicamba and each alternative herbicide a.i. Potential groundwater concentrations are 

directly related to application rate.

 The IUPAC Footprint database provides a standard estimate of groundwater concentration 

using EPA’s SCI-GROW model and assumes a consistent 1.0 kilogram per hectare 

application. Because these estimates have been calculated in the same way for dicamba and 

the alternative herbicide a.i.’s, they serve as a basis for comparison of leachability.

 The IUPAC Footprint SCI-GROW estimates were adjusted to reflect the labeled maximum 

application rate in cotton by multiplication of the application rate in kilograms per hectare.

 In a dietary risk assessment, EPA assumes that a 10 kilogram child consumes 1 liter of water 

per day. Using this standard, the SCI-GROW-estimated groundwater concentrations due to 

the maximum cotton application rate were converted to the potential exposure to a child 

arising from drinking such groundwater, in milligrams of a.i. per kilogram of body weight per 

day. This calculation provides a way to compare potential groundwater concentration to 

toxicity thresholds. The child’s water consumption was chosen over that of an adult because 

children’s waterborne exposure is greater than that of an adult on a body weight basis, so it 

represents a worst-case assessment.

 The chronic Population Adjusted Dose from EPA is shown for comparison.

 The child’s potential exposure to dicamba and each alternative herbicide a.i. via drinking 

groundwater expressed as a percentage of the cPAD. 

Dicamba’s SCI-GROW-estimated groundwater concentration (0.033 μg/L) is very small, particularly 

in relationship to dicamba’s chronic toxicity reference point (cPAD). Table C-10 shows that a child’s 

potential drinking water exposure to dicamba is calculated to be 0.0008% of the cPAD, where the 

cPAD is considered to be the highest safe chronic exposure level. Dicamba’s estimated child 

exposure level is the 6th lowest among the twenty-two potential alternative a.i.’s for which such a 

value could be calculated in this analysis; data were not available for MSMA (see below). For some 

alternative herbicide a.i.’s, the child’s potential drinking water exposure as a percentage of the 

respective cPAD was calculated to be 100- to 1000-fold higher than that of dicamba. 

Two criteria were evaluated to determine a Groundwater Risk Score as shown in Table C-10. The 

first criterion was the GUS groundwater vulnerability index, indicating whether the a.i.’s physico-

 

121 The Footprint database, as presented by IUPAC at http://sitem.herts.ac.uk/aeru/iupac/index.htm

122 Values from the Footprint database were not confirmed by comparison to values in U.S. registration documents such as REDs.
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chemical properties predict downward soil mobility. GUS values above 3.0 are rated as high or very 

high leachability potential, which was chosen as one trigger for groundwater risk. A second criterion 

was the percentage of the cPAD potentially experienced by a child consuming the SCI-GROWestimated groundwater concentration of each a.i. The % exposure above 0.1% of the cPAD was 

chosen as a second trigger for groundwater risk. A.i.’s that met both triggers, i.e., a high or very high 

GUS index and exposures > 0.1% of cPAD, were scored with a Black Circle. An a.i. that met just 

one of these two triggers was scored with a Half Circle. Those a.i.’s that met neither trigger are 

indicated in Table C-10 with a White Circle. 

Monsanto believes that for groundwater risk, dicamba offers reduced risk compared to thirteen of the 

alternative herbicide a.i.’s which were shown to have Black Circle or Half Circle scores.123 The dietary 

exposure and groundwater contamination risk could be considered relatively greater for MSMA and 

fluometuron as compared to dicamba, therefore justifying their categorization as higher groundwater 

risk with Black Circle Groundwater Risk scores. Seven alternative herbicide a.i.’s have low 

Groundwater Risk Scores and are marked with White Circles.

C.5.2.2. Surface Water and Ecological Effects on Aquatic Organisms

C.5.2.2.1. Fish and Aquatic Invertebrates

Table C-13 provides information about the hazards, exposures, and risks of dicamba DGA salt and 

each of the twenty-two alternative a.i.’s used in cotton to fish and aquatic invertebrates. For this 

analysis, 2,4-D DMA salt and 2,4-D EHE are considered separately, since they have substantially 

different water solubility. The criteria in this category include:

 Estimated environmental concentrations (EECs) of each of the seventeen (17) a.i.’s in surface 

water using the 4-day EEC as described by the Generic Estimated Environmental Concentration 

(GENEEC)124 model. This model is used by EPA to estimate a pesticide’s environmental 

exposure to aquatic ecosystems based on parameters including application rate, degradation rate, 

soil-binding properties, etc. 

 LC50 endpoints from acute fish toxicity studies or EC50 hazard values from the National Site for 

the USDA Regional IPM Centers Information System. The highest and lowest LC50 values for 

any reported fish study are listed for each a.i., regardless of species, including both fresh and 

marine species together. The purpose is to define a range of concentrations that encompass 

expected fish-toxic levels. In some cases, study results based on testing end-use formulations 

 

123 As discussed in section A.4.2.2, all alternative herbicides used in soybean production can be used safely, and do not pose an 

unreasonable risk to humans or the environment. Nonetheless, in some instances dicamba has a more benign human health or 

environmental profile compared to some alternative herbicides in the same risk category.

124 US EPA provides access to GENEEC via a downloadable executable program and users manual at 

http://www.epa.gov/oppefed1/models/water/#geneec2.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 671 of 946

were generally omitted unless data on the active ingredient was not available, or it was likely that 

formulation components did not influence the study results.

 EC50 or LC50 endpoints from acute aquatic invertebrate studies, as reported from the National 

Site for the USDA Regional IPM Centers Information System. The highest and lowest EC50 or 

LC50 values for any invertebrate study are listed, regardless of species, including both fresh water 

and marine species together. The purpose is to define a range of concentrations that encompass 

expected aquatic invertebrate-toxic levels. Studies on end-use formulations were considered as 

described above. Results attributable to formulation ingredients, such as solvents or surfactants, 

were sometimes omitted.

 Calculated Risk Quotients (RQs) for aquatic animals, comprised of fish and aquatic invertebrates 

combined together. Rather than calculate a single RQ for each species, Monsanto has calculated 

a range of potential RQs for each a.i., bracketed by the best- and worst-case values. The “best” 

RQ is derived from the ratio of the lowest reported EEC concentration divided by the highest 

LC50 or EC50 for any aquatic animal. Conversely, the “worst” RQ is derived from the ratio of the 

highest EEC concentration divided by the lowest LC50 or EC50 for any aquatic animal. The 

purpose is to define a range of RQs that span and describe the risk posed by the alternative 

herbicide to aquatic animals. The RQs that exceed the EPA’s Level of Concern (LOC) of 0.5 are 

marked in bold red font.

 The Aquatic Fish and Invertebrate Score is a means of summarizing the risk data for aquatic 

animals that is based entirely on the calculated risk quotient. A White Circle means that the 

worst-case RQ estimate < 0.05, which is EPA’s LOC for acute aquatic risk for endangered 

aquatic animals. A Half Circle means that the worst case risk quotient is greater than 0.05 and 

less than 0.5 (0.5 > RQ > 0.05). 0.5 is EPA’s LOC for acute aquatic risk for non-endangered 

animals. A Black Circle means that the worst-case RQ is greater than 0.5, indicating an acute risk 

for aquatic animals above EPA’s Level of Concern (LOC).

 The assessment and comparison summarized in Table C-13 establishes that dicamba poses little 

acute risk to aquatic animals, which is consistent with EFED’s assessment published in the 

EFED chapter in the RED (EPA 2006). The entries that exceed this LOC are those “worst 

case” values for 2,4-D (acid / salt and esters considered separately), flumiclorac pentyl, 

oxyluorfen, pyraflufen ethyl, pendimethalin, and trifluralin. These a.i.’s received a Black Circle for 

their Aquatic Fish and Invertebrate Score, and their RQ’s are highlighted in red bold font. 

 Five alternative a.i.’s (S-metolachlor, carfentrazone ethyl, fluometuron, prometryn, and 

flumioxazin) have worst case RQs above 0.05 but less than 0.5 and received a Half Circle for 

their Aquatic Fish and Invertebrate Scores. EPA considers the LOC for aquatic animals that are 

endangered species to be 0.05. The labels for herbicide products that received a Black Circle 

Aquatic Fish and Invertebrate Score and the labels for some of the herbicide products that 

received a Half-Circle Aquatic Fish and Invertebrate Score also bear warning statements for 

toxicity to fish or invertebrates based on the hazard values of those a.i.’s. Therefore, Monsanto 

concludes that dicamba presents less risk to aquatic animals than twelve of the twenty-two 

alternative herbicidal a.i.’s used on cotton as presented in Table C-13. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 672 of 946

Table C-13. Aquatic Toxicity for Fish and Aquatic Invertebrates from Acute Exposure

1 Dicamba, 2,4-D salts and esters, fomesafen, and glyphosate are expressed on acid equivalent basis. Paraquat is on a cation basis. All 

others are on an a.i. basis as stated. 

2 GENEEC is a surface water model to Estimate Environmental Concentration (EEC) used by US EPA. Further information can be 

found at 

http://www.epa.gov/pesticides/science/models_pg.htm#aquatic.

3 LC50 or EC50 hazard values from http://www.ipmcenters.org/ecotox/index.cfm. Entries are the highest and lowest values provided 

for the a.i. for fish and invertebrates, separately. [10-Apr-2013 download].

4 Risk Quotient is defined as exposure / hazard, both expressed as ppm (mg/L). “Best” means lowest exposure / hazard endpoint. 

“Worst” means highest exposure / hazard endpoint. Entries of 0 mean that the RQ is less than 0.0005 or the data was not available.

5 Aquatic Fish and Invertebrate Score: White Circle means that the worst-case RQ estimate < 0.05. Half Circle means that for the 

worst-case RQ, 0.05 < RQ < 0.5. Black Circle means that the worst-case RQ is greater than 0.5, indicating acute risk for aquatic 

animals.

6 Data for dicamba diglycolamine salt from EFED Chapter for the Dicamba RED. 

Note: As much as possible, LC50 or EC50 hazard values were chosen from tests with the technical a.i. to avoid using hazard endpoints 

that are caused by solvents, surfactants, or other formulation ingredients.

*Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated 

pest management system. Dicamba, 2,4-D salts and esters, fomesafen, and glyphosate are expressed on acid equivalent basis. 

Paraquat is on a cation basis. All others are on an a.i. basis as stated. 

Active Ingredient GENEEC2 

4-day EEC 

Aquatic Fish 

and 

Invertebrate 

Score 5

(ppm) low high low high best worst

dicamba acid /DGA salt6 0.049 > 270 - > 270 - - 0

glufosinate-ammonium 0.022 13.1 > 1000 7.5 668 0 0.003 *

glyphosate (salts) 0.0597 4 5 > 1000 > 10 934 0 0.001 *

2,4-D DMA (salts) 0.087 > 100 524 0.15 103 0.001813 0.580

2,4-D EHE (esters) 0.09 1 8 180 0.054 > 5 0.0005 1.67

flumiclorac pentyl 0.95 1.1 17.4 0.56 3 8 0.025 1.70

S-metolachlor 0.054 3.2 1 7 1.4 2 6 0.002077 0.039

oxyfluorfen 2.55 0.074 0.17 0.069 1000 0.00255 3 7

pyraflufen ethyl 74.14 0.056 9 9 0.043 121 0.612727 1724

rimsulfuron 2.33 110 1000 110 390 0.00233 0.021

thifensulfuron methyl 2.29 100 100 NA NA 0 0.023

tribenuron methyl 2.87 1000 1000 720 720 0.00287 0.004

carfentrazone ethyl 279.89 1.14 2 1.16 9.8 0.00551 0.05

fluometuron 0.107 0.64 6 5 > 1 2 2 0 0.167

fomesafen sodium 0.021 > 163 6030 22.1 397 0 0.001

paraquat dichloride 0.0026 > 1 156 > 1 1 1 0 0.0026

prometryn 0.09 > 1 1 0 1.7 2 1 0 0.052941

Pyrithiobac-sodium 0.0057 > 145 > 1000 > 140 > 910 0 0

flumioxazin 0.0016 2.3 > 21 0.23 5.5 0 0.007

MSMA 0.0498 1 2 323 77.5 173 0 0.00415

pendimethalin 0.013 0.0098 90.4 0.017 1 1 0.0001 1.33

Trifloxysulfuron-sodium 0.00068 > 97 > 104 60.1 > 119 0 0

trifluralin 18.69 0.0084 0.21 0.037 2.2 8.495 8 9

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres

Herbicide A.I.s with Potential Displacement of Postemergent Acres

Aquatic Invertebrate 

LC50 or EC5 0

3

 Range 

(ppm) 

Risk Quotient for 

Aquatic Animals 

Range 4

Exposure/Hazard

Fish LC5 0 Range 3 

(ppm) 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 673 of 946

C.5.2.2.2. Aquatic Plants

Table A-52 provides information about the hazards, exposures, and risks related to aquatic plants for 

dicamba and each of the twenty-two alternative herbicide a.i.’s used on cotton. The data format, 

sources, and methods of Estimated Environmental Concentration (EEC) calculation for aquatic 

plants are identical to those described for aquatic animals (Table C-13). A Level of Concern (LOC) 

value of 1.0 has been used for judging RQ exceedances in the case of aquatic plants, consistent with 

EPA EFED’s normal practices.

 Aquatic Plant Toxicity is based on the hazard values from the National Site for the USDA 

Regional IPM Centers Information System. Table C-14 lists the LC50 and no observed effect 

concentration (NOEC) for each named species. Entries are for the named genus with the 

lowest EC50, and the corresponding NOEC level. .

 The Risk Quotient for Aquatic Plants is defined as EEC / hazard, both expressed as ppm 

(mg/L). RQ Range is determined from the EC50 and the NOEC concentration. A Level of 

Concern (LOC) value of 1.0 has been used for judging RQ exceedance in the case of aquatic 

plants, consistent with EPA EFED’s normal practices. It should be noted that there are 

currently no threatened or endangered non-vascular aquatic plants, and therefore exceedances 

based on non-vascular plants would have no impact for listed species. 

 The Aquatic Plant Score is based entirely on the Risk Quotient for Aquatic Plants. A White 

Circle means that only the high range limit for endangered (listed) aquatic plant species 

exceeds EPA’s LOC of at most 1.0. A Half Circle means that both the RQ range limits for 

endangered (listed) plant species exceed EPA’s LOC of 1.0 for aquatic plant risk. A Black 

Circle means that both the RQ range limits for endangered (listed) plant species exceed EPA's 

LOC by more than 100.

 The assessment and comparison summarized in Table C-14 establishes that dicamba poses 

little acute risk to aquatic plants, which is consistent with EFED’s assessment published in 

the EFED chapter of the RED. Dicamba and two of the alternative herbicide a.i.’s used in 

cotton have RQs with the high range limit for aquatic plant species higher than EPA’s LOC 

of 1.0, while another two do not exceed the LOC of 1.0 even at the high range limit. Seven 

of the alternative herbicides have both the RQ range limits for aquatic plant species higher 

than EPA’s LOC of 1.0. Seven alternative herbicides have both the RQ range limits for 

aquatic species higher than EPA's LOC by more than 100. Dicamba has a lower risk for 

aquatic plant toxicity when compared to fourteen of the alternative herbicides used in cotton. 

Therefore, Monsanto concludes that dicamba offers a reduced risk opportunity for use on 

cotton with regard to aquatic plant risk.
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Table C-14. Aquatic Toxicity Parameters for Aquatic Plants for Dicamba and Alternate 

Herbicide Active Ingredients

1 Dicamba, 2,4-D salts and esters, fomesafen, and glyphosate application rates are expressed on acid equivalent basis. Paraquat is on a 

cation basis. All others are on an a.i. basis as stated. 

2 GENEEC is a surface water model to Estimate Environmental Concentration (EEC) used by US EPA. Further information can be 

found at http://www.epa.gov/pesticides/science/models_pg.htm#aquatic

3 NOEC means No Effect Concentration. Entries are for the named genus with the lowest LC50 or EC50, and the corresponding NOEC 

level. LC50 or EC50 and NOEC hazard values from http://www.ipmcenters.org/ecotox/index.cfm . [10-Apr-2013 download]

4 Risk Quotient is defined as EEC / hazard, both expressed as ppm (mg/L). RQ Range is determined from the EC50 or LC50 and the 

NOEC concentration.

5 Data are for dicamba acid from EFED Chapter for the Dicamba RED. No data are available for testing of dicamba DGA salt against 

aquatic plants.

6 Aquatic Plant Score: A White Circle means that only the high range limit is exceeds EPA's LOC of 1.0. A Half Circle means both the 

RQ range limits exceed EPA's LOC of 1.0. A Black Circle means both of the RQ range limits exceed EPA's LOC by more than 100.

Note: As much as possible, LC50 or EC50 hazard values were chosen from tests with the technical a.i. to avoid using hazard endpoints 

that are caused by solvents, surfactants, or other formulation ingredients.

*Glufosinate and glyphosate were not included in the comparison because Monsanto will recommend their use as part of an integrated 

pest management system. Active Ingredient1 GENEEC2 

4-day EEC 

Aquatic Plants Toxicity 3 

(Most Sensitive Species 

Tested)

LC50 NOEC3

Risk Quotient 

for Aquatic 

Plants 4

Aquatic 

Plant 

Score6

(ppm) Species (ppm) (ppm) RQ Range

dicamba acid /DGA salt 0.049 anabena5 0.06 0.005 0.82-9.8

glufosinate-ammonium 0.022 lemna 1.47 0.8 0.015-0.0275 *

glyphosate (salts) 0.0597 skeletonema 0.34 0.057 0.175-1.05 *

2,4-D DMA (salts) 0.087 skeletonema 0.58 0.27 0.15-0.32

2,4-D EHE (esters) 0.09 skeletonema 0.23 0.094 0.39-0.96

flumiclorac pentyl 0.95 lemna > 0.035 NA >2.7

S-metolachlor 0.054 selenastrum 0.008 0.0015 6.75-36

oxyfluorfen 2.55 selenastrum 0.00029 0.0001 8793-25500

pyraflufen ethyl 74.14 navicula 0.0015 0.00052 49426-142577

rimsulfuron 2.33 lemna 0.0116 0.00009 201-25888

thifensulfuron methyl 2.29 lemna 0.00159 0.00051 1440-4490

tribenuron methyl 2.87 lemna 0.003 0.001 957-2870

carfentrazone ethyl 279.89 lemma 0.006 0.002 46648-139945

fluometuron 0.107 anabena 0.13 0.07 0.82-1.53

fomesafen sodium 0.021 selenastrum 0.092 0.0095 0.23-2.21

paraquat dichloride 0.0026 navicula 0.00055 0.00022 4.73-11.82

prometryn 0.09 navicula 0.001 0.0003 90-300

Pyrithiobac-sodium 0.0057 lemna 0.0009 0.00027 6.33-21.11

Herbicide A.I.s with Potential Displacement of Postemergent Acres

flumioxazin 0.0016 lemna 0.00049 0.00022 3.26-7.27

MSMA 0.0498 selenastrum 5.63 < 0.3 0.009-0.17

pendimethalin 0.013 skeletonema 0.0052 0.0007 2.5-18.57

Trifloxysulfuron-sodium 0.00068 lemna 2.50E-05 2.00E-07 27.2-3400

trifluralin 18.69 navicula 0.0153 0.0046 1221-4063

Herbicide A.I.s with Potential Displacement of Preemergent Acres

Herbicide A.I.s with Potential Displacement of both Preemergent and Postemergent Acres
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 675 of 946

C.5.3. Comparative Analysis of Potential Effects on Soil, Water and Air: Dicamba and 

Alternative Herbicides

This section describes potential effects of dicamba as used on DT soybean and DGT cotton, and 

compare potential effects with the alternative herbicides evaluated above. Note that this 

assessment does not include all the herbicides used on soybean or cotton, only those most widely 

used and/or with use likely to be reduced by the introduction of DT soybean and/or DGT cotton.

C.5.3.1. Effects on Soil 

Multiple herbicides are already used in soybean and cotton production. In the U.S., 98% of 

soybean acreage was treated with an herbicide in 2006 (USDA-NASS, 2007b). Herbicides are used 

on nearly all (>99%) the cotton acres in the U.S., and over 30 herbicides, including dicamba and 

glufosinate, are registered for use on cotton. The U.S. EPA evaluated the environmental safety of 

dicamba and its metabolites as part of the RED (U.S. EPA, 2005a), and concluded that dicamba 

may accumulate with frequent and intensive use (2.0 and 2.8 lb per acre a.e. single application and 

7.7 lb per acre a.e. annually). The U.S. EPA mandated reductions in dicamba use rates as part of 

dicamba’s continued registration to effect these and other potential impacts (U.S. EPA, 2009b). 

Based on the reduced application rates (1.0 lb per acre a.e. with a maximum annual rate of 2.0 lb 

a.e. per acre), dicamba is unlikely accumulate or persist in the environment. In addition, results of 

standardized tests with dicamba and dicamba formulations indicate no long-term effects on 

functional processes of soil microorganisms (carbon respiration and nitrogen transformation) at 

rates proposed for dicamba on DT soybean (European Commission, 2007a).

Glufosinate use on DGT cotton is equivalent to currently deregulated glufosinate-tolerant cotton 

and is considered baseline. No changes in potential impacts of glufosinate on soil quality are 

anticipated.

Based on soil mobility and half live, some of the alternative herbicides for soybean and/or cotton 

are more persistent, e.g., pendimethalin, paraquat and in the case of cotton S-metolachlor. 

However, in terms of potential for long-term buildup in soil, the herbicide MSMA, which is used in 

cotton production, appears to be of much more concern than any of the herbicides. It is relatively 

immobile, and contains arsenic as a herbicidal ingredient. The arsenic does not degrade and may 

build up in the soil with repeated use of MSMA. Thus, in terms of potential impacts to soil, 

dicamba is definitely more positive than MSMA and may also be preferable to some of the more 

persistent alternative herbicides. 

C.5.3.2. Effects on Surface Water and Groundwater 

This section describes potential effects of dicamba as used on DT soybean and DGT cotton, and 

compare potential effects with the alternative herbicides evaluated above. Note that this 

assessment does not include all the herbicides used on soybean or cotton, only those most widely 

used and/or with use likely to be reduced by the introduction of DT soybean and/or DGT cotton.

It is important to recognize that, while some herbicides have greater potential to impact surface 

water or groundwater, the U.S. EPA controls these impacts through label restrictions such that 

there will be no unreasonable adverse impacts to human health or the environment when the 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 676 of 946

herbicides are used in accordance with the legally-mandated label. While some of the herbicides 

used in soybean and/or cotton have been detected in surface water or groundwater, the mere 

detection does not necessarily indicate a risk concern. 

The US-EPA reports that the major causes of surface water impairment (by number of 

impairments) in the U.S., are, in order of decreasing numbers: pathogens, metals (other than 

mercury), nutrients, organic enrichment/oxygen depletion, sediment, PCBs, mercury, pH, impaired 

biota, temperature and turbidity, which together account for 86% of all impairments (US-EPA, 

2013a). Of these, crop farming may contribute to impairment from pathogens (15% of 

impairments), metals (10% of impairments), nutrients (9.5% of impairments), sediment (8.5% of 

impairments) and turbidity (4.1% of impairments). Pathogen impairment may result from runoff 

of manure fertilizer. A few pesticides contain metals, notably arsenic, and some limited impairment 

may result from runoff of metals from these pesticides. Nutrient impairments may result from 

runoff of fertilizers (synthetic and manure) and sediment and turbidity may result from cropland 

erosion and runoff. Crop farming can also contribute to impairments from pesticides, which 

account for 2.6% of impairments (US-EPA, 2013a). However, the majority of the pesticides 

causing impairments are chlorinated chemicals such as DDT, chlordane and DDE, which are no 

longer registered for use in the U.S. 

Dicamba has been widely used in agriculture over the last four decades with dicamba’s peak use 

occurring in 1994. In the dicamba Reregistration Eligibility Decision (RED) document, EPA

considered potential risks associated with dicamba use, and its degradate 3,6-dichlorosalicylic acid 

(DCSA) when appropriate, in surface or ground water using screening level (high-end exposure) 

models to estimate environmental concentrations (U.S. EPA 2009b). The EPA then compared 

these exposure estimates to appropriate endpoints from mammalian, aquatic animal and plant 

ecotoxicity studies to determine potential impacts on human health and the environment. The 

EPA used the models PRZM/EXAMS (Pesticide Root Zone Model/Exposure Analysis Modeling 

System) and SCI-GROW (Screening Concentration in Groundwater) to estimate levels of dicamba 

in surface and ground water, respectively, using the physical, chemical, and environmental fate 

properties, and approved high-end use patterns of dicamba. 

For drinking water resources, estimated surface water concentrations were calculated by U.S. EPA 

using a simulated sugarcane crop scenario and a simulated soybean crop scenario for ground and 

aerial applications of 2.8 and 2.0 lbs a.e./acre for sugarcane and soybean, respectively. EPA’s 

modeled scenarios assumed 100% of crop acres within the watershed were treated with dicamba. 

The highest predicted concentration was 36.1 μg/L dicamba a.e., which is significantly less than the 

lifetime Health Advisory Level (HAL) of 4000 ug/L for dicamba (U.S. EPA 2005). Furthermore,

the U.S. Geological Survey National Water Quality Assessment (NAWQA) monitoring program 

also analyzed surface water in a 1993-2003 survey of surface waters of the United States, which 

included geographical areas where dicamba use has historically been most intense. Dicamba had a 

low incidence of detections (approximately 3% of samples) and the highest levels detected were 

approximately 2 μg/L, which is significantly less than the lifetime Health Advisory Level (HAL) of 

4000 ug/L for dicamba. (U.S. EPA 2005). Both the modeling predictions and the NAWQA 

monitoring results show that dicamba concentrations that might occur in drinking water are very 

low and confirm that the potential risk of dicamba leaching into groundwater or running off into 

surface water does not threaten human health or acceptable water quality. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 677 of 946

Some of the alternative herbicides for soybean and/or cotton are more soluble and/or more 

persistent in water and have higher potential for impacts to surface water, e.g., imazethapyr, 

cloransulam-methyl, fomesafen, and acetochlor. In addition, paraquat is persistent and adheres 

strongly to soil particles, and could potentially be found in surface water systems associated with 

soil particles carried by erosion, and MSMA has the potential to impact surface water with arsenic. 

Some of the alternative herbicides for soybean and/or cotton have higher potential for leaching 

and therefore impacting groundwater, e.g. imazethapyr, cloransulam-methyl, fomesafen, 

fluometuron, and the degradation products of flumioxazin. Thus, in terms of potential impacts to 

surface water and groundwater, dicamba is more positive than several of the alternative herbicides.

Surface water and associated aquatic organisms have the potential to be impacted from soybean 

and cotton production by runoff from soybean and cotton fields that may carry soil particles and 

herbicides or other pesticides to streams, rivers, lakes, wetlands and other water bodies. Tables A27 and A-51 provide comparative information concerning hazards, potential exposures, and risks 

to fish and aquatic invertebrates for alternative herbicides and for dicamba. Similar comparative 

tables aquatic plants are shown in Tables A-28 and Tables A-29. The non-target species 

assessments for aquatic animals and plants in Appendix F demonstrate that risk from exposure to 

dicamba following use on DT soybean or DGT cotton can be excluded from concern and, 

therefore, aquatic animals and plants would not be affected. Additional details can be found in 

Appendices A and F.

C.5.3.3. Potential Air Impacts

Dicamba is a low-volatility herbicide, and would be expected to have minimal air impacts. 

Dicamba does not include any fluorine atoms, which are characteristic of ozone depletion risk. 

Based on the vapor pressure presented in Table C-1, dicamba is not sufficiently volatile to be 

present in the stratosphere at ozone-threatening levels.

Alternative herbicides with relatively high volatility, such as pendimethalin (used on both soybean 

and cotton), could have localized and temporary air impacts, but none would be expected to affect 

any regulatory air quality standards. 

C.6. Conservation Tillage: Potential Benefit of DT Soybean and DGT Cotton to Soil, 

Water and Air

The positive impacts of conservation tillage or no-till systems to soil, water and air are well 

documented and include reduced soil erosion (from water and wind), improved soil tilth (including 

structure improvement and reduction in compaction), increased organic matter, improved water 

quality, increased carbon storage through enhanced soil sequestration, and conservation of soil 

moisture (CTIC 2011; U.S. EPA, 2010). 

As a result of weed shifts and the spread of weeds resistant to glyphosate and other herbicides used 

on soybean and cotton, there is a growing challenge to soil conservation gains resulting from 

conservation tillage, because of the need to manage such weeds through additional means, 

including tillage. For example, mechanical methods (machine tillage or hand-weeding) have been 

found to be one of the few consistent control options for Palmer amaranth, which has become a 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 678 of 946

frequent hard-to-control weed in southeastern cotton production (CAST 2012). The use of DT 

soybean and DGT cotton may help preserve the benefits of conservation tillage.

Growth of conservation tillage in the U.S. was greatly accelerated with the introduction of 

glyphosate-tolerant crops in large part because of the broad spectrum postemergence control 

offered by glyphosate (Price et al. 2011). By 2008 conservation tillage was employed on 

approximately 42% of the crop acres, compared to 35% in 1994 prior to the introduction of 

herbicide-tolerant crops (CTIC 2008). In 2007, approximately 27.5 million acres (39.6%) of 

soybean were planted in a no-till system (CTIC, 2007). As of 2008, conservation tillage systems are 

used on approximately 21% of the U.S. cotton acres (CTIC 2008). 

Tillage causes widespread soil disturbance. Vegetative residues protect the soil surface from the 

impact of raindrops and slow the movement of water, reducing its load-carrying potential. Slower 

moving water leads to water absorption and less run off. Runoff may carry soil particles, nutrients 

and pesticides away from fields to water bodies. Even as little as 30% residue cover typically 

reduces soil erosion rates by >50 % compared to bare ground (University of Missouri 1993). 

Typical soil loss from a field with a 93% residue cover may be only 2% of the loss from a field with 

0% residue cover (Hill and Mannering 1995). Thus, erosion of topsoil, nutrient loss, and the 

resulting sedimentation, turbidity, and transport of nutrients to streams are likely to increase with 

increased tillage.

Based on miles of impact in streams and rivers, sediments and nutrients, primarily from agricultural 

crops, are the second and third leading causes of impairment in U.S. streams and rivers (pathogens 

are the leading cause), accounting for 21% and 20% of the miles of impaired streams and rivers, 

respectively. By comparison, pesticides account for 3% of miles of impaired streams and rivers, 

and these are primarily persistent pesticides such as DDT, chlordane, and DDE, which are no 

longer used in the U.S. (U.S. EPA 2012; 2013a). EPA has projected conservation tillage to be “the 

major soil protection method and candidate best management practice for improving surface water 

quality” (U.S. EPA 2002). EPA identifies conservation tillage as the first of its CORE4 agricultural 

management practices for water quality protection (U.S. EPA 2013b). 

EPA reports conservation tillage as an agricultural practice that “increases carbon storage through 

enhanced soil sequestration” and that “may reduce energy-related CO2 emissions from farm 

equipment” (U.S. EPA, 2010). When carbon is stored, it is not available to be emitted in the form 

of carbon dioxide (CO2), a greenhouse gas.

C.7. Potential Impacts of Genetic Modifications to Soil, Water and Air

C.7.1. Potential Impacts from DT Soybean

Other than changes associated with herbicide use, DT soybean will not alter the agronomic 

practices typically utilized in the cultivation of soybean. DT soybean has been found to be 

compositionally, agronomically and phenotypically equivalent to conventional soybean. The 

phenotypic, agronomic, and environmental interaction assessment of DT soybean included a near 

isogenic conventional soybean control and the commercial reference varieties. Characteristics 

assessed included: seed dormancy and germination, pollen morphology, and symbiont interactions 

conducted in the laboratory and greenhouse; and plant phenotypic and agronomic evaluations and 
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environmental interaction observations conducted in the field. The commercial soybean reference 

varieties grown concurrently were used to establish a range of natural variability for each assessed 

characteristic in soybean. The phenotypic, agronomic, and environmental interaction assessment 

demonstrated that DT soybean is equivalent to the conventional control. Therefore, microbial 

populations and associated biochemical processes in soil are not expected to change with the 

introduction of DT soybean. For symbiont interactions, there were no statistically significant 

differences (5% level of significance) observed between DT soybean and the conventional control 

for any of the parameters measured, including pollen viability and diameter, nodule number and 

dry weight, shoot total nitrogen, and shoot and root dry weight. Based on these data, the 

cultivation of DT soybean is not expected to impact microbial populations and associated 

biochemical processes. 

Because the genetic modification itself will not affect agronomic practices, and DT soybean has 

been found to be compositionally, agronomically and phenotypically equivalent to conventional 

soybean, DT soybean will not affect water or air differently than commercially available soybean. 

Potential impacts from changes in herbicide use are discussed in Sections C.4 and C.5.

C.7.2. Potential Impacts from DGT Cotton

Other than changes associated with herbicide use, DGT cotton will not alter the agronomic 

practices typically utilized in the cultivation of cotton. DGT cotton has been found to be 

compositionally, agronomically and phenotypically equivalent to conventional cotton. The 

phenotypic, agronomic, and environmental interaction assessment of DGT cotton included the 

parental conventional control and a range of commercial reference varieties as comparators. 

Characteristics assessed included: seed dormancy and germination, pollen morphology, plant 

phenotypic observations, plant mapping, and environmental interaction evaluations conducted in 

the field. The phenotypic, agronomic, and environmental interaction assessment demonstrated 

that DGT cotton is comparable to conventional cotton. In an individual site assessment of abiotic 

stress response and disease damage, no differences were observed between DGT cotton and the 

conventional control for any of the 296 comparisons for the assessed abiotic stressors or for any of 

the 299 comparisons for the assessed diseases among all observations at the 26 replicated field sites 

across the U.S. cotton producing region. In an assessment of arthropod-related damage, no 

differences were detected between DGT cotton and the conventional control for any of the 288 

comparisons for the assessed arthropods. The lack of significant biological differences in plant 

responses to abiotic stress, disease damage, and arthropod-related damage for DGT cotton support 

the conclusion that the introduction of the dicamba and glufosinate tolerance traits are unlikely to 

result in increased plant pest potential or an altered environmental impact from DGT cotton 

compared to commercially cultivated cotton. Therefore, microbial populations and associated 

biochemical processes in soil are not expected to change with the introduction of DGT cotton. 

Based on these data, the cultivation of DGT cotton is not expected to impact microbial 

populations and associated biochemical processes. 

Because the genetic modification itself will not affect agronomic practices, and DGT cotton has 

been found to be compositionally, agronomically and phenotypically equivalent to conventional 

cotton, DGT cotton will not affect water or air differently than commercially available cotton. 

Potential impacts from changes in herbicide use are discussed in Sections C.4 and C.5.
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Herbicide (EPA Reg. No. 524-582). EPA Pesticide Regulation Notice 97-3.

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Conservation 66:265-275.

Price, A.J., K.S. Balkcom, S.A. Culpepper, J.A. Kelton, R.L. Nichols and H. Schomberg. 2011. 

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738-R-95-006. April, 1996.

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Protection Agency Office of Pesticides, Prevention, and Toxic Substances. Document No. EPA 

738-R-97-007, June, 1997.

U.S. EPA. 1994. Memorandum. Response to January 14, 1994 memo from A. Maciorowski of 

EEB to H. Jacoby of EFGWB concerning acetochlor and alachlor. February 14.

U.S. EPA. 1997. Pesticide Fact Sheet: Cloransulam-methyl. U.S. Environmental Protection Agency 

Office of Pesticides, Prevention, and Toxic Substances. October 29, 1997.

U.S. EPA. 2001. Pesticide Fact Sheet: Flumioxazin. U.S. Environmental Protection Agency Office 

of Pesticides, Prevention, and Toxic Substances. April 12, 2001.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 682 of 946

U.S. EPA. 2002. Environmental implications of conservation tillage: A systems approach. 

EPA/600/D-85/147 (NTIS PB85237089). U.S. Environmental Protection Agency, Office of 

Research and Development, National Exposure Research Lab, Washington, D.C. 

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e=PR&TIMSType=&showCriteria=0&address=nerl&view=citation&keyword=Pesticides&sortBy=

pubDateYear&count=100&dateBeginPublishedPresented [Accessed May 19, 2010].

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EPA/600/D-85/147 (NTIS PB85237089). U.S. Environmental Protection Agency, Office of 

Research and Development, National Exposure Research Lab, Washington, D.C. 

http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=39100&fed_org_id=770&SITyp

e=PR&TIMSType=&showCriteria=0&address=nerl&view=citation&keyword=Pesticides&sortBy=

pubDateYear&count=100&dateBeginPublishedPresented [Accessed May 19, 2010].

U.S. EPA. 2003. Flumioxazin: Environmental Fate and Ecological Risk Assessment. U.S. 

Environmental Protection Agency Office of Pesticides, Prevention, and Toxic Substances. August 

14, 2001.

U.S. EPA. 2003b. Reregistration Eligibility Decision for Diuron. U.S. Environmental Protection 

Agency Office of Pesticides, Prevention, and Toxic Substances. September 30.

U.S. EPA. 2004. Memorandum: Preliminary Tier 1 Drinking Water Assessment for Chlorimuronethyl Use on Soybeans, Peanuts and Non-crop Land. U.S. Environmental Protection Agency Office 

of Pesticides, Prevention, and Toxic Substances. April 16, 2004.

U.S. EPA. 2005. Reregistration Eligibility Decision for 2,4-D. U.S. Environmental Protection 

Agency Office of Pesticides, Prevention, and Toxic Substances. Document No. EPA 738-R-05-002, 

June, 2005.

U.S. EPA. 2005. Dicamba: HED chapter of the reregistration eligibility decision document, phase 1. 

PC Code 029801; DP Barcode: D317720. U.S. Environmental Protection Agency, Health Effects 

Division, Office of Prevention, Pesticides and Toxic Substances, Washington, D.C.

U.S. EPA. 2005a. Dicamba: HED chapter of the reregistration eligibility decision document, phase 

1. PC Code 029801; DP Barcode: D317720. U.S. Environmental Protection Agency, Health Effects 

Division, Office of Prevention, Pesticides and Toxic Substances, Washington, D.C.

U.S. EPA. 2005a. EFED Reregistration Chapter For Dicamba / Dicamba Salts. U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, DP Bar 

Code 317976, August 31, 2005.

U.S. EPA. 2006. Revised Reregistration Eligibility Decision for MSMA, DSMA, CAMA and 

Cacodylic Acid. U.S. Environmental Protection Agency Office of Pesticides, Prevention, and Toxic 

Substances. August, 2006.

U.S. EPA. 2009. Memorandum: Correction to the amendments to the dicamba RED. U.S. 

Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances, 

Washington, D.C.
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U.S. EPA. 2009. Reregistration eligibility decision for dicamba and associated salts. U.S. 

Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances, 

Washington, D.C.

U.S. EPA. 2009b. Registration eligibility decision for dicamba and associated salts. U.S. 

Environmental Protection Agency, Office of Pesticides, Prevention, and Toxic Substances, June 8, 

2006, as amended June 17, 2009.

U.S. EPA. 2010. Agricultural practices that sequester carbon and/or reduce emissions of other 

greenhouse gases. U.S. Environmental Protection Agency, Washington, D.C. 

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U.S. EPA. 2011. 2011 Edition of the drinking water standards and health advisories. U.S. 

Environmental Protection Agency, Washington, D.C.

U.S. EPA. 2012. Watershed assessment, tracking & environmental results: National summary of 

state information. U.S. Environmental Protection Agency, Washington, D.C. 

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U.S. EPA. 2012a. Watershed assessment, tracking & environmental results: National summary of 

state information. U.S. Environmental Protection Agency, Washington, D.C. 

http://iaspub.epa.gov/waters10/attains_nation_cy.control [Accessed April 18, 2013].

U.S. EPA. 2012b. National assessment database. U.S. Environmental Protection Agency, 

Washington, D.C. http://www.epa.gov/waters/305b/index.html [Accessed May 1, 2013].

U.S. EPA. 2013. Agriculture management practices for water quality protection. U.S. Environmental 

Protection Agency, Washington, D.C. 

http://cfpub.epa.gov/watertrain/moduleFrame.cfm?module_id=33&parent_object_id=1362&obje

ct_id=1362 [Accessed April 29, 2013].

U.S. EPA. 2013. Specific state causes of impairment that make up the national pesticides cause of 

impairment group for threatened and impaired rivers and streams. U.S. Environmental Protection 

Agency, Washington, D.C. 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_wbtype_detail?p_cause_group_nam

e=PESTICIDES&p_wbtype=STREAM/CREEK/RIVER&p_wtype_display=Rivers%20and%20S

treams&p_sz_column=%20size_1&p_sz_unit=miles [Accessed April 30, 2013].

U.S. EPA. 2013b. Agriculture management practices for water quality protection. U.S. 

Environmental Protection Agency, Washington, D.C. 

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ct_id=1362 [Accessed April 29, 2013].

University of Missouri. 1993. Conservation tillage and residue management to reduce soil erosion. 

University of Missouri Extension, Columbia, Missouri. http://extension.missouri.edu/p/G1650

[Accessed April 29, 2013].
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University of Missouri. 1993. Conservation tillage and residue management to reduce soil erosion. 

University of Missouri Extension, Columbia, Missouri. http://extension.missouri.edu/p/G1650 

[Accessed April 29, 2013].

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Agriculture National Agricultural Statistics Service, Washington, D.C. Online: 

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Agriculture, National Agricultural Statistics Service, Washington, D.C.

US-EPA, 2013a. National Summary of Impaired Waters and TMDL Information. [Accessed 8-22-2013].
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 685 of 946

APPENDIX D: POTENTIAL FOR SPRAY DRIFT AND VOLATILIZATION TO 

AFFECT ADJACENT CROP & NON-CROP AREAS, AND MITIGATION MEASURES
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Table of Contents

D.1 Introduction ......................................................................................................................................688

D.2 Pesticide Regulation & Registration ..............................................................................................688

D.3 Use of Dicamba on DT soybean and DGT Cotton...................................................................689

D.4 Spray Drift.........................................................................................................................................690

D.4.1 Prevention of Spray Drift..................................................................................................690

D.4.2 Monsanto’s Proposed Label Instructions.......................................................................691

D.4.2.1 Reduction of Small Droplets...............................................................................693

D.4.2.2 Determination of Proper Buffer Distances.......................................................695

D.4.2.3Applicator Education and Awareness................................................................701

D.5 Volatilization.....................................................................................................................................702

D.5.1 DGA Salts Reduce Volatilization.....................................................................................702
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Tables and Figures

Table D-1. Soybean Field Studies with Dicamba......................................................................................697

Table D-2. Comparison of No Effect Rates for Plant Height and Yield from Dicamba 

Application to Soybeans..................................................................................................................698

Table D-3. Effect of dicamba on yield in plant species other than soybean .......................................700
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D.1 Introduction

Offsite movement of dicamba from spray drift or volatilization is a concern due to the 

potential for effects to off-target vegetation, including sensitive crops and threatened or

endangered species, and effects on air quality. An herbicide could undergo offsite movement 

via air transport from the intended application site either by particle drift during spray 

application or by post-application volatilization from treated surfaces. Drift is “the 

movement of pesticide droplets or particles through the air at the time of pesticide 

application or soon thereafter from the target site to any non- or off-target site. Spray drift 

shall not include movement of pesticides to non- or off-target sites caused by erosion, 

migration, volatility, or windblown soil particles that occurs after application ” (US-EPA, 

2001). Volatilization of herbicides occurs when the substance vaporizes at atmospheric 

pressure and moves offsite. A variety of factors impact a given herbicide’s potential for drift 

or volatilization. Monsanto is proposing a multi-faceted approach to address any potential 

for off-site movement of dicamba used on DT soybean or DGT cotton, described herein. 

D.2 Pesticide Regulation & Registration 

Although APHIS has traditionally conducted a range of analyses under the National 

Environmental Policy Act (NEPA) in connection with petitions for deregulation, APHIS 

does not have any statutory authority to regulate herbicide uses in agriculture. Instead the 

use of a pesticide is regulated by the U.S. Environmental Protection Agency (EPA) under 

the Federal Insecticide Fungicide and Rodenticide Act (FIFRA).125

EPA regulates under FIFRA the herbicides that are applied to GE herbicide-tolerant crops 

like DT soybean and DGT cotton. Each pesticide (including herbicides) must be labeled 

with enforceable directions for use on a crop by crop basis. It is a violation of FIFRA to use 

any registered pesticide in a manner inconsistent with its labeling, subject to criminal and 

civil penalty. For that reason, an approved herbicide cannot be lawfully used on a 

corresponding herbicide-tolerant crop, unless EPA approves a label amendment for such 

use.

EPA’s use restrictions are included in the FIFRA label for any given pesticide. EPA’s labels 

describe, among other things, how a pesticide can be applied to a given crop and any 

restrictions on the use of the pesticide. Use of any pesticide not in compliance with the label 

is unlawful under FIFRA. For that reason, before a pesticide can be used on an herbicidetolerant crop, the pesticide manufacturer must seek approval – which, in the case of DT 

soybean and DGT cotton, is a label amendment – for that pesticide. 

Before EPA can approve any registration or label, EPA must find that the use/registration 

“will not cause unreasonable adverse effects on humans and the environment.” In addition, 

if EPA finds that an approved herbicide use presents “unreasonable hazard to ... species 

 

125 7 U.S.C. §136 et seq.
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declared endangered or threatened by the [Endangered Species Act],” EPA may immediately 

suspend the pesticide’s registration. 7 U.S.C. §§136(l), 136d(c).

In addition to EPA’s FIFRA authority, EPA also regulates potential human-health impacts 

from pesticides under the FFDCA. EPA does so by establishing “tolerance levels” (i.e., “the 

amount of pesticide that may remain on food products”) under the FFDCA. The FFDCA 

“defines pesticide tolerances as ‘safe’ when there is ‘a reasonable certainty that no harm will 

result from aggregate exposure to the pesticide chemical residue.’ 

EPA considers possible effects from offsite movement as part of the pesticide registration 

process required under FIFRA. Additionally, pesticide registrants must report drift incidents 

to EPA as an adverse effect in order to ensure the pesticide continues to meet FIFRA 

requirements for registration. 40 C.F.R. § 159.195(a)(2). Before any registered herbicide can 

be applied to any new use site (including any deregulated GE-derived crop), EPA must 

approve a label amendment setting out the use pattern and specific application requirements 

for that new use site. Specifically, in order to approve a new use of a pesticide , EPA must 

conclude that no unreasonable adverse effects will result from the new use when applied 

according to label directions, which includes potential offsite movement. Offsite impacts are 

diminished when herbicides are applied in accordance with label instructions. Registered 

herbicides, including dicamba and glufosinate, are assessed by EPA for potential risks to

non-target plants. A detailed discussion of the use of dicamba herbicide in the U.S. can be 

found in Appendix A.

D.3 Use of Dicamba on DT soybean and DGT Cotton

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is a broad-spectrum, selective, postemergence systemic herbicide with activity on a wide range of annual and perennial 

broadleaf plants. It was first registered in the United States in 1967 and is widely used in 

agricultural, industrial and residential settings. Dicamba controls annual, biennial and 

perennial broadleaf weeds in monocotyledonous crops and grasslands, and it is used to 

control brush and bracken in pastures. Because of the sensitivity of broadleaf plants to 

dicamba, the uses of dicamba in broadleaf crops until now have been limited to early preemergence and pre-harvest applications. DT soybean and DGT cotton have been 

developed to exhibit tolerance to dicamba herbicide applications by the insertion of a 

demethylase gene from Stenotrophomonas maltophilia. As a result DT soybean and DGT cotton 

express the dicamba mono-oxygenase (DMO) protein that rapidly demethylates dicamba to 

form the herbicidally inactive metabolite DCSA. 

The use of dicamba is projected to increase if DT soybean and DGT cotton are deregulated. 

Please see Appendix A to this Environmental Report for a detailed discussion of the 

projections for increased use of dicamba in this scenario. 

Offsite movement of herbicide to sensitive crops and plants during application is a concern 

during the growing season (Jordan et al. 2009). The potential for effects to off-target crops 

from offsite movement due to spray drift is generally greatest with a postemergence 

application because the treatment is made directly to the crop and requires the spray 

equipment to be higher above the ground, which results in more spray drift potential. In 

addition, postemergence herbicides typically have foliar activity, thereby increasing the 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 690 of 946

potential of foliar effects or visual symptoms on desirable plants. The presence of dicamba 

can cause visible morphological effects to trees and certain sensitive crops, particularly beans 

(e.g., dry and snap beans), cotton, flowers, fruit trees, grapes, ornamentals, peas, potatoes, 

soybean, sunflower, tobacco, tomatoes, and other broadleaf plants when contacting their 

roots, stems or foliage (BASF Corporation 2008; Jordan et al. 2009). These plants are most 

sensitive to dicamba during their development or growing stage (BASF Corporation 2008).

Please see Appendix F of this Environmental Report for a detailed discussion of the 

potential impacts on wildlife, plants and ecosystems, including threatened and endangered 

species.

D.4 Spray Drift 

Spray drift of herbicides is a familiar and well-studied phenomenon, notably by the Spray 

Drift Task Force, of which Monsanto is a member. EPA defines drift as “the movement of 

pesticide through air at the time of application or soon thereafter, to any site other than that 

intended for application” (US-EPA, 2000). Factors affecting the occurrence of spray drift 

include application equipment and method, weather conditions, topography, and the type of 

crop being sprayed (US-EPA, 2000). Aerial application is associated with an increased drift 

potential compared to ground spray application because the herbicide is released at a greater 

distance above the crop canopy. In addition to the method of application, spray drift 

potential is also impacted by equipment type (e.g., nozzle types and ratings), settings (e.g., 

spray pressure, application speed, and application volume), equipment maintenance, 

environmental conditions (wind speed, temperature inversion), applicator behavior and 

distance from the edge of the application area (SDTF, 1997; Felsot et al., 2010).

D.4.1 Prevention of Spray Drift

Growers and commercial herbicide applicators have been applying dicamba to agricultural 

row crops for over 40 years. This experience has provided valuable knowledge and learning 

on the proper application of dicamba for effective weed control and also for minimizing 

offsite movement to sensitive crops. Spray drift can be reduced during application by using 

industry standard procedures for minimizing spray drift. Depending upon the herbicide 

being used, factors for managing the potential for spray drift include the selectivity and 

sensitivity of the herbicide, local weather conditions at the time of application (wind, 

temperature, humidity, inversion potential), droplet size distribution, application volume, 

boom height (height of the application equipment above the crop canopy), sprayer speed, 

and distance from the edge of the application area (SDTF, 1997; Felsot et al., 2010). The 

minimization of droplets less than 150 microns is important in reducing any potential for 

spray drift. Droplet size can be increased by requiring the use of certain nozzle types,

reducing spray pressure, increasing volume per minute spray rates, and by specifying an 

application volume per acre rate of at least 10 gallons. (SDTF, 1997; Teejet Technologies, 

2011). Arvidsson et al. (2011) investigated meteorological and technical factors affecting 

total spray drift and determined that boom height and wind speed were the primary factors 

affecting the potential for spray drift among those tested, followed by air temperature, 

driving speed and vapor pressure deficit. Arvidsson et al. (2011) demonstrated that drift 

increased with driving speed. This increase was attributed to either air flows associated with 

the forward movement of the sprayer or to increased vertical boom movement. 
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EPA’s Office of Pesticide Programs (OPP), which regulates the use of pesticides in the U.S., 

encourages pesticide applicators to use all feasible means available to them to minimize offtarget drift. The Agency has introduced several initiatives to help address and prevent issues 

associated with drift. Currently, EPA is evaluating new regulations for pesticide drift 

labeling and the identification of best management practices to control such drift (US-EPA, 

2009a), as well as identifying scientific issues surrounding field volatility of conventional 

pesticides (US-EPA, 2010). Additionally, OPP and EPA’s Office of Research and 

Development are developing a new voluntary program, the Drift Reduction Technology 

(DRT) Program, which encourages the development, marketing and use of application 

technologies verified to significantly reduce spray drift (US EPA, 2009a).

When herbicides are applied according to the FIFRA label application instructions, offsite 

impacts can be avoided. EPA concluded in the dicamba RED (U.S. EPA, 2009b) that 

existing label language to mitigate offsite movement was sufficient to reduce the potential 

risk of damage to adjacent vegetation. Because the proposed application rates for dicamba 

on DT soybean and DGT cotton are less than or equivalent to rates for dicamba established 

for other uses in the dicamba RED, and because these uses were evaluated by EPA as part 

of the RED and the proposed label contains the offsite movement mitigation language, it is 

reasonable to conclude that the use of dicamba on DT soybean and DGT cotton also meets 

the FIFRA no unreasonable effects standard for drift and offsite movement (U.S. EPA,

2009b). 

Growers and commercial applicators follow label directions and restrictions, and are 

educated by university specialists and industry representatives on the proper application 

equipment, equipment setup, and climatic conditions to maximize herbicide performance 

and minimize offsite movement of herbicides. For example, with the introduction of 

glyphosate-tolerant crops and the subsequent increase in glyphosate use, university 

specialists conducted extensive education programs on proper application procedures and 

precautions (Dr. W. Johnson – Purdue University, 2010 personal communication). 

Equipment manufacturers have developed spray nozzles that provide uniform coverage for 

effective weed control while applying larger spray droplets to reduce the potential for 

particle drift. 

D.4.2 Monsanto’s Proposed Label Instructions

Monsanto is proposing a multi-faceted approach to address potential for off-site movement 

of dicamba used on DT soybean and DGT cotton. Monsanto has proposed a range of 

application restrictions on its dicamba label that would be legally-binding on the 

grower/applicator. Collectively, these restrictions (which are currently pending before EPA) 

would go far beyond any other currently applicable limitations on dicamba application—

indeed go beyond any label restrictions ever imposed on dicamba in the nearly half century 

that dicamba has been on the market.126 Monsanto proposes to EPA that the supplemental 

 

126 For example, Monsanto’s proposed limits are far more restrictive than those for Dicamba Max 4, which 

allows aerial applications and does not require the use of drift-reducing additives. See Dicamba Max 4 Label, 
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labels for M1691 Herbicide use on DT soybean and DGT cotton contain application 

requirements that would minimize dicamba offsite movement, summarized as follows:

 No aerial application of M1691 Herbicide. 

 Use only spray nozzles that produce extremely coarse to ultra-coarse spray droplets 

and minimal amounts of fine spray droplets as defined by the American Society of 

Agricultural and Biological Engineers (ASABE S-572.1) and follow nozzle 

manufacturer’s recommendations to deliver desired droplet size.

 Apply using a minimum of 10 gallons of spray solution per acre.

 Select a ground speed under 15 mph that will deliver the desired spray volume while 

maintaining the desired spray pressure.

 Spray at the appropriate boom height based on nozzle selection and nozzle spacing 

(not more than 24 inches above target pest or crop canopy). Set boom to lowest 

effective height over the target pest or crop canopy based on equipment 

manufacturer’s directions.

 When making applications in low relative humidity, set up equipment to produce 

larger droplets to compensate for evaporation.

 Do not apply during a temperature inversion. 

 Survey the application site for neighboring sensitive areas prior to application. A 

potential way of locating sensitive areas is through the use of sensitive crop registries.

127

 Do not apply when the wind is blowing in the direction of a sensitive area at a wind 

speed greater than 10 mph. Sensitive areas include known habitat for threatened or 

endangered species, non-target sensitive crops, residential areas, and greenhouses.

 Implement a spray buffer (to be determined by EPA) between the last treated row 

and the closest downwind edge of any sensitive area when the wind is blowing in the 

direction of a sensitive area at a speed of 10 mph or less.

 Do not apply if wind speed is greater than 15 mph. 

 

http://www.kellysolutions.com/erenewals/documentsubmit/KellyData/ND/pesticide/Product%20Label/83222/83222-

14/83222-14_DICAMBA_MAX_4_3_10_2009_6_06_42_PM.pdf. 

127 For example, www.driftwatch.org
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 693 of 946

 Do not use crop oil concentrate or methylated seed oil as adjuvants when applied 

with glyphosate-based agricultural products. Do not add acidifying buffering agents.

 Clean equipment immediately after using this product using the procedures outlined 

in the label.

These proposed label instructions and/ or any measures imposed by EPA will limit the 

offsite movement of dicamba via spray drift and inadvertent spray application for the 

reasons described in more detail in the following paragraphs.

D.4.2.1 Reduction of Small Droplets

Monsanto has taken a variety of important measures to reduce offsite spray drift, including 

proposing label requirements to minimize the factors that result in small droplet generation, 

suspension, and movement into non-target areas. The factors that affect spray drift and 

associated impacts to adjacent areas can be divided into three main categories: a) droplet 

size and number, b) droplet transport, and c) the physical location of the spray. Droplet size 

and number is controlled by the nozzle type, application volume, spray pressure, and 

additives in the tank. Droplet transport is affected by wind speed, boom height, air 

temperature, vapor pressure deficit128, and application speed. The third factor includes the 

proximity to sensitive non-target species which can be controlled through a mandate that 

applicators be aware of sensitive areas - including areas where threatened or endangered 

species may be present - that could be impacted from a dicamba application and implement 

a no-spray buffer as specified on the label. 

D.4.2.1.1 Droplet Size and Number 

The minimization of droplets less than 150 microns is important in reducing any potential 

for spray drift. Nozzles used for application of agricultural products do not produce 

droplets of one uniform size, but rather produce a spectrum of droplet sizes (TeeJet 

Technologies, 2011). Nozzles are generally classified as very fine, fine, medium, coarse, very 

coarse, extremely coarse, or ultra-coarse by comparison of a nozzle’s droplet size distribution 

when spraying water to that of a set of standard nozzles. ASABE has established a nozzle 

classification system in its published standard, ASABE S-572.1 (Wilson, 2011a; ASABE, 

2009), which is the U.S. industry standard for agricultural spray drop size classification. 

Nozzles classified as Extremely Coarse to Ultra Coarse have a small percentage of the spray 

volume in droplets with diameters less than 150 microns.

Nozzle orifice size and operating pressure also affect the droplet size spectrum for a given 

nozzle type (SDTF, 1997). The relationship between orifice size, operating pressure, spray 

volume delivered, and droplet size classification can be found in the nozzle manufacturers’ 

 

128 Vapor pressure deficit is the difference between the amount of water vapor in the air and the amount of 

water vapor in the air at saturation. Evaporation reduces droplet size, and the greater the vapor pressure deficit 

the more rapid the evaporation and the greater the potential for drift.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 694 of 946

catalogs. The use of a larger orifice size allows the application to be made at a higher 

volume per minute rate without increasing the operating pressure, and consequently 

reducing the droplet size classification (TeeJet Technologies, 2011). Additionally, a higher 

volume per minute rate allows the spray volume per acre to be higher at a given operating 

speed. Specifying an application volume per acre of at least 10 gallons may result in the use 

of larger orifice nozzles for some equipment to reduce the percentage of small droplets with 

the higher potential to drift. 

The proposed label instructions direct the applicator to employ all of the relevant practices –

including nozzle type, operating pressure, and application volume – to ensure that the 

droplet size distribution can be classified as extremely coarse to ultra-coarse – which limits 

the percentage of spray droplets in the size category that has the potential to move offsite.

D.4.2.1.2 Reduction of the Transport of Small Droplets

Arvidsson et al. (2011) investigated meteorological and technical factors affecting total spray 

drift and determined that boom height and wind speed were the primary factors affecting the 

potential for spray drift among those tested, followed by air temperature, driving speed and 

vapor pressure deficit. Establishing a maximum wind speed (15 mph, or 10 mph if sensitive 

areas are downwind) limits the distance that fine droplets will travel before settling. A 

temperature inversion129 can result when wind speeds are less than 3 mph, and can cause the 

suspension of the small spray droplets for extended periods of time. Prohibiting application 

during inversion conditions avoids the potential for suspension and farther transport of fine 

spray droplets (Wilson, 2011b). 

Boom height is also restricted in the proposed application use instructions for dicamba to 

the minimum height required to get a uniform spray pattern in order to minimize the 

amount of time that spray droplets are suspended before settling to the ground (Wilson, 

2011c). As shown in the Spray Drift Task Force information booklet on Ground 

Applications (SDTF, 1997), a difference in boom height between 20 and 50 inches can 

impact the extent to which spray volume may move offsite by allowing additional time for 

the droplets to be blown offsite before settling. Prohibiting aerial application and limiting 

the boom height for ground applications to 24 inches above the target pest or crop canopy 

will minimize the amount of time that spray droplets are suspended and available to move 

offsite.

Arvidsson et al. (2011) demonstrated that drift increased with driving speed. This increase 

was attributed to either air flows associated with the forward movement of the sprayer or to 

increased vertical boom movement. Limiting driving speed to 15 mph or less will minimize 

this potential contributing factor. 

 

129 A temperature inversion occurs when the air at the soil surface is cooler than the air above. Since cool air 

sinks, the surface air layer does not mix with upper layers of air. Under this condition, spray droplets are 

trapped near the surface and may stay suspended for increased periods of time.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 695 of 946

D.4.2.1.3 Physical Location of the Spray and Use of Wind Buffers

Awareness of the presence of sensitive areas and whether the wind direction at the time of 

application may move any suspended spray droplets toward a sensitive area are important 

considerations at the time of application. Since the implementation of the DriftWatchTM 

130program in Indiana, drift incidents onto sensitive crops have been significantly reduced 

(Hahn, 2011). This program has now been expanded to several states across the major 

Midwest soybean growing area and to some Great Plains states as well (IL, IN, MI, MN, 

MO, WI, CO, MT, and NE). Under some circumstances, a buffer may be needed to provide 

further protection to a sensitive area. This method is highly effective when used. 

For these reasons, the proposed FIFRA product labels state that applicators should consult 

with available sensitive crop registries prior to making dicamba applications to DT soybean 

or DGT cotton. Many state lead agriculture agencies (IA, IL, IN, KS, MI, MN, MO, NE, 

OK, WI) have developed tools and resources to assist the applicator in the location of 

sensitive areas, such as vegetable or organic production fields, in an effort to minimize 

commercial impacts associated with pesticide offsite movement. Furthermore, prior to 

commercialization of DT soybeans and DGT cotton, Monsanto will implement an 

endangered species mitigation system for dicamba. The implemented system will either be 

an EPA-specific system and/or a web-based system, similar to that currently available for 

glyphosate at PreServe.org. This will facilitate applicator and grower implementation of use 

restrictions for protection of threatened and endangered non-monocotyledonous terrestrial 

plant species.

D.4.2.2 Determination of Proper Buffer Distances 

Monsanto has submitted information to the EPA that summarizes studies conducted at eight 

field locations to assess the buffer distance required to be protective of survival, growth, and 

reproduction of plant species that are very sensitive to dicamba (Orr et al., 2012). These 

studies utilized nozzles that fit the droplet size classification requirements, the minimum 

application volume and the maximum boom height requirements specified above. 

Justification for use of soybean plant height as the endpoint for risk assessment

Soybean was selected as the test species since it has been shown to be a highly sensitive 

indicator species for post-emergence dicamba effects. In the vegetative vigor study 

conducted in a greenhouse with the DGA salt of dicamba, soybean had the lowest endpoint 

of the ten species tested (Porch et al., 2009). Comparable sensitivity for soybean to that 

observed in the greenhouse has also been displayed in field studies (Al-Khatib and Peterson, 

 

130 Driftwatch is a voluntary program that allows growers to reports locations of fields in which sensitive crops 

are being grown (and also identified other types of sensitive areas such as organic fields). The sensitive crop 

information is presented on a website in a map format which can then be utilized by pesticide applicators prior 

to application.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 696 of 946

1999; Auch and Arnold, 1978; Kelley et al., 2005; Wax et al., 1969; and Weidenhamer et al., 

1989). See Table D-1 for a summary of endpoints from these studies.

Higher Dicamba rates are needed to cause effects on soybean yield than are needed 

to cause effects on soybean plant height at early growth stages

Effects of dicamba on plant growth have been evaluated by considering effects on plant 

height at very sensitive early growth stages. Effects of dicamba on plant reproduction can be 

evaluated by assessing the effect of dicamba on plant species seed or fruit yields. A number 

of the field studies (Al-Khatib and Peterson, 1999; Auch and Arnold, 1978; Kelley et al., 

2005; Wax et al., 1969; Weidenhamer et al., 1989; and Wright, 2012) indicate that soybean 

yield is no more sensitive, and is generally less sensitive, to dicamba treatment than is 

soybean plant height at the early growth stages at which studies to estimate buffer distances 

have been conducted. Additionally, results of these studies demonstrate that significant 

morphological effects in soybeans such as plant height reduction do not always result in yield 

reduction, but yield reduction in soybeans occurs at rates greater than that affecting soybean 

plant height at the early vegetative stages which were used in studies for buffer distance 

estimation. See Table D-2 for a summary of the results of these studies. 

Dicamba effects on yields of other crops occur at rates greater than or equal to rates 

affecting soybean plant height

The effects of dicamba on crop yield have been reported by a number of investigators in at 

least eleven other crops besides soybean. Monsanto has submitted field data on soybean to 

EPA and conducted an extensive review of relevant literature for use by EPA in establishing 

an appropriate buffer distance from potentially sensitive plant communities. The field data 

was generated across multiple growing seasons with diverse geographic and climatic 

conditions. The literature review included results from studies testing 12 possible sensitive 

crops, with many crops tested across multiple growing seasons and/or geographies and/or 

growth stages. The potential sensitive crops included in these studies were soybean, tomato, 

cantaloupe, cotton, pea, peanut, pepper, potato, sugarbeet, sunflower, tobacco, and 

watermelon. 

These studies also indicate that the dicamba no effect rate for soybean plant height at 

vegetative growth stages is a lower value (approximately 0.3 g a.e./ha) than the dicamba no 

effect rates for plant yield in these other species that have been tested. See Table D-3 for a 

summary of endpoints from these studies.

Because soybean plant height measured at vegetative growth stages is a more sensitive 

endpoint for dicamba effects than soybean yield or yield of eleven other plant species in five 

additional plant families, the use of the soybean plant height endpoint is appropriate to 

assess potential dicamba effects on survival, growth, and reproduction of sensitive species. 

Monsanto’s application management practices, including buffer distances that have been 

determined to not result in soybean plant height reduction after dicamba applications, can 

therefore be considered effective measures for mitigation of potential effects of dicamba on 

non-target plants.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 697 of 946

Table D-1. Soybean Field Studies with Dicamba

Growth Stage & 

Other 

Treatment 

Information

Dicamba Salt

a

Time of 

Measurement

Plant Height

No Effect 

Rate 

(g a.e./ha)b

Reference

2-3 trifoliate 

1997 Not Specified 60 DAT <5.6 Al-Khatib and Peterson, 1999

2-3 trifoliate 

1998 Not Specified 60 DAT 5.6 Al-Khatib and Peterson, 1999

1-2 trifoliate -

1974 DMA At maturity 56 Auch and Arnold 1978

3-4 trifoliate -

1974 DMA At maturity 1 Auch and Arnold, 1978

6-7 trifoliate -

1974 DMA At maturity 1 Auch and Arnold, 1978

V3 DMA At maturity < 1.1 Wax et al., 1969

Williams -

prebloom 1980 

(41 DAP)

DMA At maturity 0.32c Weidenhamer et al., 1989

Elf - prebloom 

1980 (41 DAP) DMA At maturity 1.3c Weidenhamer et al., 1989

V3 DGA

Full height 

before leaf 

senescence

< 0.56 Kelley et al., 2005

V7 DGA

Full height 

before leaf 

senescence

< 0.56 Kelley et al., 2005

a DMA – dimethylamine; DGA – diglycolamine

bFor conversion of g a.e./ha to lb a.e./A divide the g a.e./ha value by 1120. Application rates expressed as 

oz/A were assumed to be of a 4 lb a.e./gal formulation and were converted to g a.e./ha

c Highest rate at which less than 10% effect on height was observed based on Table 2 of the publication
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 698 of 946

Table D-2. Comparison of No Effect Rates for Plant Height and Yield from Dicamba 

Application to Soybeans

Growth Stage & 

Other Treatment 

Information

No Effect Rate (g a.e./ha)a

Reference Plant Height Yield

Williams - prebloom 

1980 0.32b,c 20b Weidenhamer et al., 1989

Elf - prebloom 1980 1.3b,c 10b Weidenhamer et al., 1989

8-12 inches, 3 WAEd, 

RM1 2009 -- 11 Johnson et al., 2012

8-12 inches, 3 WAE, 

RM2 2009 -- 41 Johnson et al., 2012

8-12 inches, 3 WAE, 

RM1 2010 -- 3 Johnson et al., 2012

8-12 inches, 3 WAE, 

RM2 2010 -- 3 Johnson et al., 2012

2-3 trifoliate 1997 5.6e 17 Al-Khatib and Peterson, 1999

2-3 trifoliate 1998 <5.6e 17 Al-Khatib and Peterson, 1999

V3f - SE Farm -- < 5.6 Andersen et al., 2004

V3 - Brookings Farm -- < 5.6 Andersen et al., 2004

V3 < 1c 1 Wax et al., 1969

V3 < 0.56c < 0.56g Kelley et al., 2005

1-2 trifoliate - 1974 56c 56 Auch and Arnold 1978

3-4 trifoliate - 1974 1c 56 Auch and Arnold, 1978

6-7 trifoliate - 1974 1c 56 Auch and Arnold, 1978

V7h < 0.56c 0.56 Kelley et al., 2005

Early bloom - 1974 1c 11 Auch and Arnold, 1978

Early bloom - 1975 1c,i 1 Auch and Arnold, 1978

Early bloom - 1976 < 11c < 11 Auch and Arnold, 1978

R2j NAk < 1 Wax et al., 1969

R2 NA 0.56 Kelley et al., 2005

Elf - midbloom 1980 NA 40b Weidenhamer et al., 1989

Mid-bloom - 1976 NA 28 Auch and Arnold, 1978

Williams - midbloom 

1980 NA 10b Weidenhamer et al., 1989

Williams - midbloom 

1981 NA 7.4b Weidenhamer et al., 1989

Early-pod - 1975 NA 11 Auch and Arnold, 1978

Early pod - 1976 NA 11 Auch and Arnold, 1978

Late pod - 1976 NA 28 Auch and Arnold, 1978

a For conversion of g a.e./ha to lb a.e./A divide the g a.e./ha value by 1120. Application rates expressed as 

oz/A were assumed to be of a 4 lb a.e./gal formulation and were converted to g a.e./ha

b Highest rate at which less than 10% and 20% effect on height and yield, respectively, were observed based on 

Table 2 & Table 3 of the publication

c Height at maturity

d WAE – weeks after emergence
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 699 of 946

e Assessed at 60 days after treatment

f At V3 growth stage the third trifoliate leaf is unfolded 

(http://extension.agron.iastate.edu/soybean/production_growthstages.html)

g Yield reduction was statistically significant but not considered biologically significant at rates of 0.56 and 5.6 g 

a.e./ha because a ten-fold increase in rate did not cause an increase in the yield reduction, and the percent 

reduction is small compared to the untreated control (i.e., less than 10% yield reduction).

hAt V7 growth stage the seventh trifoliate leaf is unfolded.

i A height reduction of 18% was observed at rates above 1 g a.e./ha, but this reduction was not statistically 

significant

j R2 growth stage is when there is an open flower at one of the two uppermost nodes 

(http://extension.agron.iastate.edu/soybean/production_growthstages.html)

k Rates at which no effect on plant height are provided in the literature references, but are not provided here 

since yield values are being compared to rates causing plant height effects at earlier time points.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 700 of 946

Table D-3. Effect of dicamba on yield in plant species other than soybean

Crop

Growth Stage & 

Other Treatment 

Information

Effect

No Effect 

Rate 

(g a.e./ha)a

Reference

Soybean pre-bloom Plant Height 0.32b Weidenhamer et al, 1989

Cantaloupe 3 Weeks after 

transplanting Total Harvest 560 Hynes and Weller, 2010

Cantaloupe 3 Weeks after 

transplanting Total Harvest 11.2 Hynes et al., 2011

Cotton Cot – 2 Leaf Lint Yield 140 Everitt and Keeling, 2009

Cotton

4-5 Leaf

Pinhead Square

First Bloom

Lint Yield 14 Everitt and Keeling, 2009

Cotton

20-30 cm tall

RM 2009

LW 2009

LW 2010

Yield 140 Johnson et al., 2012

Cotton 20-30 cm tall

RM 2010 Yield 11 Johnson et al., 2012

Cotton 6-8 Leaf Lint Yield 2.8 Marple et al., 2007

Cotton

3-4 Leaf

8-node

14-node

18-node

Lint Yield 2.8 Marple et al., 2008

Pea Flower buds 

formed Yield 6.25 c Al-Khatib and Tamhane, 1999

Pea Vegetative & 

Flowering

Seed dry 

weight 5.63 Olszyk et al., 2009

Peanut 15-20 cm width

RM 2010 Yield 140 Johnson et al., 2012

Peanut

15-20 cm width

RM 2009

LW 2010

Yield 41 Johnson et al., 2012

Peanut

15-20 cm width

LW 2009 Yield 11 Johnson et al., 2012

Pepper 3 Weeks after 

transplanting Total harvest 11.2 Hynes and Weller, 2010

Pepper 3 Weeks after 

transplanting Total harvest 560 Hynes and Weller, 2010

Pepper 3 Weeks after 

transplanting Total harvest 560 Hynes et al., 2011

Potato 11-15 Days after 

emergence

Tuber fresh 

weight 5.58 Olszyk et al., 2010

Potato 15% flowering Tuber Yield 11.2 Leino and Haderlie, 1985

Sugarbeet 10-15 leaf Extractable 

sucrose

70 Schroeder et al., 1983

Sugarbeet 10-15 leaf Root yield >140 Schroeder et al., 1983
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 701 of 946

Crop

Growth Stage & 

Other Treatment 

Information

Effect

No Effect 

Rate 

(g a.e./ha)a

Reference

Sunflower 2-4 leaf Yield 1.6 Derksen, 1989

Tomato Full bloom - 1972 Total Yield 1 Jordan and Romanowski, 1974

Tomato Green fruit stage 

1971 Total Yield 20 Jordan and Romanowski, 1974

Tomato Green fruit stage 

1972 Total Yield 100 Jordan and Romanowski, 1974

Tomato 3 Weeks after 

transplanting

Total Yield

Fruit weight

11.2

5.6 Hynes and Weller, 2010

Tomato 3 Weeks after 

transplanting Total Yield 560 Hynes et al., 2011

Tomato 15 cm tall

Early vegetative

Marketable 

Fruit 0.9d Kruger et al., 2012

Tomato 25 cm tall

Early bloom

Marketable 

Fruit 0.5d Kruger et al., 2012

Watermelon 3 Weeks after 

transplanting

Total Harvest 11.2 Hynes and Weller, 2010

Watermelon 3 Weeks after 

transplanting

Total Harvest 560 Hynes et al., 2011

a For conversion of g a.e./ha to lb a.e./A divide the g a.e./ha value by 1120. Application rates expressed as oz/A were 

assumed to be of a 4 lb a.e./gal formulation and were converted to g a.e./ha

b Lowest rate from 

c Next rate below rate with greater than a 25% effect on yield (lowest such rate of 5 sites). 25% effect on yield was 

chosen due to high variability.

dValue from dose response curve estimated to result in 1% fruit loss

D.4.2.3 Applicator Education and Awareness

As mentioned above, growers and commercial applicators are aware of the sensitivity of 

certain crops to dicamba and the extra precautions that should be taken in making dicamba 

applications when these crops are nearby. In addition, growers and commercial applicators 

follow label directions and restrictions, and growers are educated by university specialists and 

industry representatives on the proper application equipment, equipment setup, and climatic 

conditions to maximize herbicide performance and minimize offsite movement of 

herbicides. To provide growers with specific information for dicamba applications to 

dicamba-tolerant crops, Monsanto is implementing a robust stewardship program that will 

include a strong emphasis on grower and applicator training. In addition, U.S. EPA and 

state agencies have enforcement authority over the use of any registered pesticide in a 

manner inconsistent with its labeling.

For example, following the introduction of glyphosate-tolerant crops and the subsequent 

increase in use of the non-selective herbicide glyphosate, university specialists conducted 

extensive education programs on proper application procedures and precautions (Dr. W. 

Johnson – Purdue University, 2010 personal communication). Equipment manufacturers 

developed spray nozzles that provide uniform coverage for effective weed control while 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 702 of 946

applying larger spray droplets to reduce the potential for particle drift. Similarly, offsite 

movement of dicamba has been managed with the knowledge of the proper spray equipment 

and equipment setup, climatic conditions for accurate, on-target applications, and based on 

the requirements for applying dicamba at an appropriate distance from sensitive crops and 

plants (Jordan et al. 2009). 

D.5 Volatilization 

Volatilization of fertilizers and pesticides from soil and plant surfaces also introduces certain 

chemicals to the air and can cause offsite movement. A substance is volatile if it is likely to 

vaporize at atmospheric pressure. The USDA Agricultural Research Service (ARS) is 

conducting a long-term study to identify factors that affect pesticide levels in the Chesapeake 

Bay region airshed (USDA-ARS, 2011). This study has determined that volatilization is 

highly dependent upon exposure of disturbed unconsolidated soils, and that variability in 

measured compound levels is correlated with temperature and wind conditions. Another 

ARS study of volatilization of certain herbicides after application to fields has found 

moisture in dew and soils in higher temperature regimes significantly increases volatilization 

rates (USDA-ARS, 2011). 

Physicochemical characteristics of the individual chemical have been shown to have little 

impact on spray drift. However, unlike spray drift, the potential for post-application 

volatilization is primarily a function of the physicochemical properties of the chemical, (e.g., 

vapor pressure, Henry’s Law constant, etc.), method of application (e.g., soil-incorporated or 

not), and the local environmental conditions (e.g., temperature, humidity, wind speed). Due 

to this complexity, the potential for post-application vapor loss is often measured 

experimentally.

In EFED’s Chapter in the Dicamba RED, laboratory volatility data have been summarized 

for potassium and dimethylamine (DMA) salts of dicamba from a moist soil. Monsanto has 

also submitted information to the EPA that summarizes a field study that was conducted to 

measure the volatilization rate of a dicamba DGA salt formulation from foliage.

D.5.1 DGA Salts Reduce Volatilization 

Monsanto seeks to minimize volatile loss from treated soybean and cotton fields by labeling 

optimal formulations and salt forms of dicamba. The DGA salt formulation of dicamba, 

which is proposed for use on DT soybean and DGT cotton, has low volatility. Side-by-side 

field experiments have indicated that a formulation of the diglycolamine (DGA) salt of 

dicamba dramatically reduced volatilization of dicamba compared to a similar formulation of 

the DMA salt form and that volatility is not a significant component of offsite movement 

for the DGA salt of dicamba (Egan, 2012). The use of formulations of, or similar to, the 

DGA salt of dicamba will help to limit non-target plant risk due to post-application vapor 

loss. In the publication, the authors state, “Our data demonstrate that the diglycolamine 

formulation has a dramatic effect on reducing dicamba vapor drift. Estimates of total g acid 

equivalent vapor drift outside of the treated area were reduced 94% relative to the 

dimethylamine formulation, and the dose-distance curves indicate that predicted mean 

exposures drop close to zero only short distances away from the treated area.” Additionally, 

measured air concentrations when using the DGA salt were at least 70-fold lower than those 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 703 of 946

in the potassium and DMA salt laboratory studies EFED evaluated, even though the 

application rate was twice that of DMA (Mueller et al., 2013).

Monsanto has requested the use of dicamba on DT soybean and DGT cotton only for lowvolatility salts, including the DGA salt formulation (U.S. EPA Reg. No. 524-582). Specific 

application requirements on the proposed FIFRA product label (currently pending before 

EPA), and/or any other measures imposed, by EPA will minimize dicamba offsite 

movement. Monsanto plans to continue to invest in research and development of new 

dicamba formulations for use with DT soybean and DGT cotton. Monsanto and BASF 

have submitted separate applications to EPA seeking the approval of novel dicamba 

formulations (EPA File Symbols 7969-GUL, 524-ANO and 524-ARN). EPA will review 

relevant data and information as a part of its registration process and confirm that the 

product when used according to the approved label directions meets the FIFRA standard 

before granting a registration including the use on DT soybean or DGT cotton. 

Furthermore, Monsanto will not allow growers to use dimethylamine salt (DMA) of dicamba 

and/or dicamba acid on DT soybean or DGT cotton.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 704 of 946

References for Appendix D 

Al-Khatib, K. and D. Peterson. 1999. Soybean (Glycine max) response to simulated drift 

from selected sulfonylurea herbicides, dicamba, glyphosate, and glufosinate. Weed 

Technology 13: 264-270.

Al-Khatib, K. and A. Tamhane. 1999. Dry pea (Pisum sativum L.) response to low rates of 

selected foliar- and soil-applied sulfonylurea and growth regulator herbicides. Weed 

Technology 13: 753-758.

Andersen, S.M., S.A. Clay, L.J. Wrage and D. Matthees. 2004. Soybean foliage residues of 

dicamba and 2,4-D and correlation to application rates and yield. Agronomy Journal 96: 750-

760.

American Society of Agricultural and Biological Engineers (ASABE). 2009. S-572.1: Spray 

Nozzle Classification by Droplet Spectra.

Arvidsson, T., L. Bergström and J. Kreuger. 2011. Spray drift as influenced by 

meteorological and technical factors. Pest Management Science 67: 586-598.

Auch, D.E. and W.E. Arnold. 1978. Dicamba use and injury on soybeans Glycine max in 

South Dakota, USA. Weed Science 26: 471-475.

BASF Corporation. 2008. Clarity®herbicide label. BASF Corporation, Research Triangle 

Park, North Carolina.

Derksen, D.A. 1989. Dicamba, chlorsulfuron, and clopyralid as sprayer contaminants on 

sunflower (Helianthus-annuus), mustard (Brassica juncea), and lentil (Lens culinaris), 

respectively. Weed Science 37: 616-621.

Egan, J.F. and D.A. Mortensen. 2012. Quantifying vapor drift of dicamba herbicides applied 

to soybean. Environmental Toxicology and Chemistry 31: 1023-1031.

Everitt, J.D. and J.W. Keeling. 2009. Cotton growth and yield response to simulated 2,4-D 

and dicamba drift. Weed Technology 23: 503-506.

Felsot, A.S., J.B. Unsworth, J.B.H.J. Linders, G. Roberts, D. Rautman, C. Harris and E. 

Carazo. 2010. Agrochemical spray drift; Assessment and mitigation—A review. Journal of 

Environmental Science and Health, Part B 46: 889-911.

Hahn, L., L. Theller, A. Reimer and B. Engel. 2011. Pesticides sensitive crops and habitats: 

Registry implementation results. American Chemical Society, Washington, D.C. [Accessed 

December 12, 2011] 

http://www.agrodiv.org/documents/denver11/Endangered%20Species%20Act%20and%2

0Regulation/AGRO223_Hahn_Leighanne.pdf.

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APPENDIX E: HEALTH AND SAFETY RISKS OF DICAMBA TO THE 

GENERAL POPULATION & WORKERS
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Table of Contents

E.1 Introduction.............................................................................................................................................711

E.2 Pesticide Registration, Reregistration and Tolerance Setting ...........................................................711

E.2.1 Pesticide Human Risk Assessment......................................................................................713

E.3 Dicamba Regulatory Status in U.S. ......................................................................................................714

E.3.1 Dicamba – Registration History ..........................................................................................714

E.4 Overview of Dicamba Herbicide .........................................................................................................715

E.4.1 Properties of Dicamba Herbicide........................................................................................716

E.4.2 Toxicology of Dicamba Plant and Animal Metabolites...................................................718

E.5 Potential Impact of Dicamba on Human Health...............................................................................721

E.5.1 Dicamba Safety Evaluations for Consumers.....................................................................721

E.5.2 Dicamba – Proposed New Use on DT Soybean and DGT Cotton – General 

Population Including Infants and Children ....................................................................724

E.5.3 Dicamba Safety Evaluation for Applicator........................................................................727
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Tables and Figures

Figure E-1. Structure of Dicamba ..............................................................................................................715

Table E-1. Dicamba Acid Acute Toxicity Study Findings......................................................................716

Table E-2. Dicamba Acid Reproductive, Developmental, Mutagenic, and Neurotoxicologic 

Findings .............................................................................................................................................717

Table E-3. Dicamba Acid Subchronic, Chronic and Cancer Findings.................................................718

Figure E-2. Structure of DCSA ..................................................................................................................719

Table E-4. Summary of Toxicological Findings from Testing of DCSA.............................................720

Table E-5. Summary of Dietary Exposure and Risk for Dicamba: Food and Water........................723

Table E-6. Aggregate (Short-term) Exposure Assessment for Dicamba .............................................724

Table E-8. Residues of Dicamba, DCSA, 5-Hydroxydicamba and DCGA in DT Soybean 

Forage, Hay and Seed ......................................................................................................................725

Table E-9. Residues of Dicamba, DCSA, 5-Hydroxydicamba and DCGA in DGT Cotton 

Seed and Gin By-products..............................................................................................................726
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E.1 Introduction

This appendix describes the health and safety risks to U.S. consumers and to workers involved in 

soybean and cotton farming operations. Cotton and soybean are broad acre, highly managed crops 

where herbicides are used on essentially all (> 98%) commercially cultivated crop acres. Potential 

risks to consumers from the production of cotton and soybean may occur from herbicide use which 

can result in residues in food or by from exposure to novel proteins present in the GE plant. 

The following assessment considers potential risks from the use of dicamba on DT soybean and 

DGT cotton, in addition to potential risks from herbicide use in practice today. The assessment of 

potential risks to consumers from exposure to food derived from DT soybean and DGT cotton, 

and food derived from animals fed DT soybean or DGT cotton is discussed in Appendix H.

Dicamba use is regulated at the federal level by EPA, not APHIS. APHIS’s authority under the 

Plant Protection Act does not allow it to specify conditions for the use of pesticides, including 

herbicides. Instead, EPA specifically approves labeling for any pesticide use, including uses on 

agricultural crops. EPA regulates under FIFRA the pesticides that are used with crops, including 

GE herbicide-tolerant crops like DT soybean and DGT cotton. FIFRA requires all pesticides to be 

registered before distribution or sale, unless they are exempted. Under FIFRA, EPA must approve 

each distinct pesticide product, each distinct use pattern, and each distinct use site. Each crop for 

example, constitutes a unique use site and no registered pesticide may be applied to any crop unless 

EPA has approved that specific pesticide/crop use. 

Each pesticide must be labeled with enforceable directions for use on a crop by crop basis. It is a 

violation of FIFRA to use any registered pesticide in a manner inconsistent with its labelling, subject 

to criminal and civil penalty.131 For that reason, an approved herbicide cannot be lawfully used on a 

corresponding herbicide-tolerant crop, unless EPA approves a label amendment for such use.

E.2 Pesticide Registration, Reregistration and Tolerance Setting

FIFRA requires that before the sale or distribution of a new pesticide or a new use of a registered 

pesticide, a company must obtain a registration, or license, from EPA. The EPA must ensure that 

the pesticide, when used according to its label directions, will not cause unreasonable adverse effects 

on human health and the environment. In order to address this standard, EPA evaluates potential 

risks to humans and the environment, and may require applicants to submit more than 100 different 

scientific studies conducted according to EPA guidelines. According to EPA, more than 1000 active 

ingredients are currently registered as pesticides in the U.S., which are, in turn, formulated into many 

thousands of pesticide products that are available in the marketplace (U.S. EPA, 2010). 

Pesticide registration is a scientific, legal, and administrative procedure through which EPA 

examines the ingredients of the pesticide; the particular site or crop on which it is to be used; the 

amount, frequency, method and timing of application, and other conditions of its use; and storage 

and disposal practices. In evaluating a pesticide registration application, EPA assesses a wide variety 

 

131 FIFRA §12(a)(2)(G) and §14
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of data indicating the potential human health and environmental effects associated with use of the 

pesticide product. The data required by EPA are used to evaluate a wide array of potential impacts, 

including whether a pesticide has the potential to cause adverse effects on humans, wildlife, fish, and 

plants (including endangered species and other non-target organisms, i.e., organisms that the 

pesticide is not intended to act against). The registration applicant must also supply data on the 

pesticide’s potential impact on surface water and ground water, should leaching or runoff occur. 

The potential human health and safety risks assessed range from short-term toxicity to long-term 

effects such as cancer and reproductive system disorders. 

Pesticide label directions are considered as part of EPA’s evaluation. All pesticides must meet the 

FIFRA standard ensuring that they do not pose unreasonable adverse effects to humans or the 

environment before they can be registered., In addition, each pesticide must be labeled with 

enforceable directions for use on a crop by crop basis. It is a violation of FIFRA to use any 

registered pesticide in a manner inconsistent with its labelling, subject to criminal and civil penalty.132 

For that reason, an approved herbicide cannot be lawfully used on a corresponding herbicidetolerant crop, unless EPA approves a label amendment for such use. 

The registration of a new pesticide is not EPA’s only opportunity to evaluate the product’s safety. 

EPA has recently completed a program to review older pesticides (those initially registered before 

November 1984) under FIFRA to ensure that they meet current scientific and regulatory standards. 

Reregistration, like the initial registration process, considers the human health and ecological effects 

of pesticides and results in actions to reduce risks that are of concern. 

Where pesticides may be used on food or feed crops, EPA also sets pesticide tolerances, i.e., 

maximum pesticide residue levels that can legally remain in or on foods. EPA undertakes this 

analysis under the authority of the Federal Food, Drug, and Cosmetic Act (FFDCA). Under the 

FFDCA, EPA must find that such tolerances will be safe, meaning that there is a reasonable 

certainty that no harm will result from aggregate exposure to the pesticide residue. This finding 

must be made and the appropriate tolerance established before a pesticide can be registered for use 

on the particular food or feed crop in question. EPA must consider several factors before a 

tolerance can be established, including:

• the aggregate, non-occupational exposure from the pesticide (exposure through diet, 

from using pesticides in and around the home, and from drinking water);

• the cumulative effects from exposure to different pesticides that produce similar 

effects in the human body;

• evidence of increased susceptibility to infants and children, or other sensitive 

subpopulations, from exposure to the pesticide; and 

• evidence that the pesticide produces an effect in humans similar to an effect 

produced by a naturally occurring estrogen or produces other endocrine-disruption effects.

 

132 FIFRA §12(a)(2)(G) and §14
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E.2.1 Pesticide Human Risk Assessment

The process EPA uses for evaluating the health impacts of a pesticide, under either FIFRA or 

FFDCA, is called risk assessment. EPA uses the National Research Council’s four-step process to 

assess potential human health risks. This process involves hazard identification, dose-response 

assessment, exposure assessment and risk characterization. Each of these steps is discussed below.

The first step in the risk assessment process is hazard identification to identify potential health 

effects, or hazards, which may occur from different types of pesticide exposure. EPA considers the 

full spectrum of a pesticide’s potential health effects. Hazards are identified through a battery of 

studies that examine the potential toxicity of the pesticide in various tests including, where 

appropriate, tests with laboratory animals.

To assess human health risk of the pesticide, pesticide companies conduct many toxicity studies 

based on EPA guidelines and the Good Laboratory Practice (GLP) standards. Results are evaluated 

for acceptability by EPA scientists. EPA evaluates pesticides for a wide range of effects, from eye 

and skin irritation to cancer and birth defects. EPA may also consult the public literature or other 

sources of information on any aspect of the chemical. 

The next step of the risk assessment is dose-response assessment which considers the levels at 

which the pesticide produces adverse effects. Dose levels at which adverse effects were observed in 

test animals are then translated into equivalent doses for humans.

Step three of the process involves an exposure assessment. People can be exposed to pesticides in 

three ways: 

1. Inhaling pesticides (inhalation exposure), 

2. Absorbing pesticides through the skin (dermal exposure), and 

3. Ingesting pesticides (oral exposure). 

Depending on the situation, pesticides could enter the body by any one or all of these routes. 

Typical sources of pesticide exposure include food (following agricultural uses); home and personal 

use pesticides; pesticides applied to lands that make their way into the drinking water; or 

occupational exposure for agricultural workers or pesticide applicators. 

Risk characterization is the final step in assessing human health risks from pesticides. It is the 

process of combining the hazard, dose-response and exposure assessments to describe the overall

risk from the use of a pesticide. It explains the assumptions used in assessing exposure as well as the 

uncertainties that are built into the dose-response assessment. The strength of the overall database 

is considered, and broad conclusions are made. EPA’s role is to evaluate both toxicity and exposure 

and to determine the risk associated with use of the pesticide. 

The risk to human health from pesticide exposure depends on both the toxicity of the pesticide and 

the likelihood of people coming into contact with it, i.e., the probability of exposure. At least some 

exposure and some toxicity are required to result in a risk. For example, if the pesticide is found to 

have a high level of toxicity, but people are not exposed to the pesticide, there is no risk. Likewise, 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 714 of 946

if there is ample exposure but the pesticide is nontoxic, there is no risk. Typically, however, there is 

some toxicity and exposure, which results in a potential risk. 

EPA recognizes that effects vary between animals of different species and from person to person. 

To account for this variability, a 100-fold uncertainty factor is built into the risk assessment with a 

10X factor to account for differences between test species and humans, and a 10X factor to account 

for differences between people. This uncertainty factor creates an additional margin of safety for 

protecting people who may be exposed to the pesticides. The Food Quality Protection Act (FQPA) 

requires EPA to use an additional, up to a 10-fold safety factor, if necessary, to protect special 

subpopulations if they show potential increased susceptibility to effects of the pesticide, typically 

infants, children or women of child-bearing age. 

Once EPA completes the risk assessment process for a pesticide, the Agency uses this information 

to determine if there is a reasonable certainty of no harm to human health as a result of the use of 

the pesticide according to label directions as required by FIFRA. Using the conclusions of a risk 

assessment, EPA can then make an informed decision regarding whether to approve a pesticide 

chemical or use, as proposed by the product label, or whether additional protective measures are 

necessary to limit exposure to a pesticide. For example, EPA may prohibit pesticide use on certain 

crops because consuming the treated commodity may result in an unacceptable risk to consumers. 

Another example of protective measures is requiring workers to wear personal protective equipment 

(PPE) such as a respirator or chemical resistant gloves, or not allowing workers to enter treated crop 

fields until a specific period of time has elapsed (Restricted Reentry Interval or REI). If, after 

considering all appropriate risk reduction measures, the pesticide still does not meet EPA’s safety 

standard, the Agency will not allow the proposed chemical or use. Regardless of the specific 

measures enforced, EPA’s primary goal is to ensure that legal uses of the pesticide are protective of 

human health, especially the health of children, and the environment. 

E.3 Dicamba Regulatory Status in U.S.

E.3.1 Dicamba – Registration History

Dicamba is a selective broadleaf herbicide belonging to the auxin agonist class, the oldest known 

class of synthetic herbicides, and is a member of the benzoic acids sub-group. Dicamba mimics the 

action of the plant hormone indole acetic acid, and causes rapid uncontrolled cell division and 

growth, leading to plant death. Dicamba has been registered in the U.S. for use on food crops since 

1967 (U.S. EPA, 2009) and has been widely used in agricultural production for over forty years. 

Dicamba is presently approved for use on asparagus, corn, cotton, grass seed production, pastures 

and rangelands, small cereals (including wheat), sorghum, soybean, and sugarcane. Dicamba is also 

used for industrial vegetation management (e.g., forestry and roadsides), professional turf 

management (e.g., golf courses, sports complexes), and residential turf (U.S. EPA, 2009; Durkin and 

Bosch, 2004).

Dicamba has a complete and comprehensive regulatory database (toxicity, environmental fate, and 

ecological toxicity) that has been evaluated by the United States Environmental Protection Agency 

(U.S. EPA). A Reregistration Eligibility Decision (RED) for dicamba was completed by EPA in 

2006 and subsequently amended in 2008 and 2009 (U.S. EPA, 2009), as required for continued 

registration of all pesticides originally registered prior to 1984. EPA concluded the available data 

submitted for dicamba are complete and adequate to support the continued registration of dicamba 
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products. EPA has evaluated the available toxicity data and concluded that a high level of 

confidence exists in the quality of the dicamba data base and in the reliability of the dicamba toxicity 

endpoints for risk assessment. EPA also considered toxicity data and available information 

concerning the variability of sensitive subpopulations, including infants and children. The EPA 

concluded there is reasonable certainty that no harm will result to the general population, or to 

infants and children, as a result of aggregate (all) exposure to dicamba residues. Thus, all current 

dicamba uses were eligible for reregistration (U.S. EPA, 2008a; U.S. EPA, 2008b; U.S. EPA, 2008c). 

In 2008, dicamba also successfully completed reevaluation by the Pest Management Regulatory 

Agency of Health Canada (PMRA, 2008) and the European Commission Health and Consumer 

Protection Directorate-General (European Commission, 2008). Dicamba has been approved by the 

EPA for a number of food and feed uses, including the major agricultural crops of corn, soybean 

and small grains (e.g., wheat or barley). Dicamba presently has 68 food and feed pesticide tolerances 

(40 CFR §180.227) established in support of these uses. 

In soybean, dicamba is presently registered for preemergence (early pre-plant) applications up to 

0.5 pound acid equivalence per acre (lb a.e./A) and late postemergence (pre-harvest) applications at 

rates up to 1.0 lb a.e./A, and a pesticide tolerance is established for residues of dicamba on soybean 

seed (10 ppm) in support of these uses. 

In cotton, dicamba is presently registered for preemergence (early pre-plant) applications up to 

0.25 pound acid equivalence per acre (lb a.e./A), and a pesticide tolerance is established for residues 

of dicamba on cotton seed, undelinted (0.2 ppm) in support of these uses. 

E.4 Overview of Dicamba Herbicide

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is a carboxylic acid that can form salts in aqueous 

solution. The chemical structure is provided in Figure E-1. Dicamba products registered for 

agricultural uses are formulated with various dicamba salts. The formulated products Clarity and 

M1691 contain the diglycolamine salt of dicamba at a nominal level of 56.8% by weight, which is 

equivalent to 38.5% by weight dicamba acid (also referred to acid equivalents or a.e.). 

O

CH3

Cl

Cl

O OH

Figure E-1. Structure of Dicamba
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E.4.1 Properties of Dicamba Herbicide

Both dicamba, as the Clarity or the M1691 formulation, and glyphosate, as various Roundupbranded formulations, have “CAUTION!” signal words (CAUTION is the most favorable of three 

possible label signal words that can be required by EPA) and favorable chronic toxicity profiles. In 

a comparative analysis with other alternative soybean weed control products, dicamba products offer 

better, or at least equivalent, human health safety profiles, as discussed below.

In 2006, EPA issued the Reregistration Eligibility Decision (RED) document for dicamba and its 

associated salts (U.S. EPA, 2009). The RED document, and the related Health Effects Division 

(HED) chapter (U.S. EPA, 2005b), presented an overview of the toxicological properties of 

dicamba, which is summarized below.

The measurement of human health is the result of conventional laboratory testing against standard 

indicator species (generally rats, mice, and dogs) and is required for the registration of a pesticide by 

the EPA. Results are presented using standard toxicity indices, such as the concentration or dose 

required for 50% lethality (LC50 or LD50), the highest dosing level that produced No Observable 

Adverse Effects (NOAEL), or the lowest dosing level that produced an Observable Adverse Effect 

(LOAEL). The results of the acute (single exposure) toxicity studies for dicamba are presented in 

Table E-1. Results for developmental, reproduction, mutagenic and neurotoxicological studies are 

presented in Table E-2. Subchronic, chronic and carcinogenicity study results are presented in Table 

E-3.

Table E-1. Dicamba Acid Acute Toxicity Study Findings

Study Endpoint EPA Category1

Acute oral (rat) LD50 2740 mg/kg III

Acute dermal (rat) LD50 2000 mg/kg III

Acute inhalation (rat) LC50 5.3 mg/L IV

Primary eye irritation (rabbit) Irritant II

Primary dermal irritation (rabbit) Irritant II

Dermal sensitization (guinea pig)2 Negative NA

1EPA acute toxicity categories range from I (worst) to IV (best).

2Determination of the potential to cause or elicit skin sensitization reactions (allergic contact 

dermatitis) is an important element in evaluating a substance’s toxicity.
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Table E-2. Dicamba Acid Reproductive, Developmental, Mutagenic, and Neurotoxicologic 

Findings

Study

Systemic Toxicity Endpoint

(mg/kg body wt/day)

Offspring Toxicity 

Endpoint (if any)

(mg/kg body wt/day)

Developmental (rat) Maternal NOAEL 160; LOAEL 400. 

Clinical signs: decreased food 

consumption and weight gain, 

increased mortality.

Developmental 

NOAEL 400 (HDT1).

Developmental 

(rabbit)

Maternal NOAEL 62.5; LOAEL 150. 

Clinical signs: decreased motor activity, 

ataxia, increased abortion.

Developmental 

NOAEL 62.5; LOAEL 

150. Clinical signs: 

Increased abortion.

Developmental 

Neurotoxicity

Not Required

Reproduction, 

multigeneration (rat)

Parental NOAEL 122/136 (M/F2); 

LOAEL 419/450 (M/F). Clinical 

signs: reduced righting reflex. 

Reproductive NOAEL 122; LOAEL 

419. Delayed F1 male maturation.

Offspring NOAEL 45;

LOAEL 136. Clinical 

signs: Decreased pup 

weights, all generations.

Acute Neurotoxicity 

(rat)

NOAEL not established; LOAEL 300. 

Clinical signs: Impaired gaits and 

righting reflex, impaired respiration, 

rigidity.

Subchronic 

Neurotoxicity (rat)

NOAEL 401/472 (M/F); LOAEL 

768/1029 (M/F). Clinical signs: 

Rigidity, slightly impaired gait and 

righting reflex.

Gene Mutation –

Salmonella

Not mutagenic.

Chromosome 

aberration (CHO3)

Aberrations not induced at any tested 

concentration with or without S9 

activation.

Unscheduled DNA 

Synthesis (UDS)

No Evidence of UDS up to 3000 

μg/mL

1HDT stands for the highest dose tested.

2M/F stands for males/females.

3Chinese hamster ovaries.
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Table E-3. Dicamba Acid Subchronic, Chronic and Cancer Findings

Study

Toxicity Endpoints 

(mg/kg body weight/day)

Subchronic Oral (rat) NOAEL 479/536 (M/F1); LOAEL 

1000/1065 (M/F). Clinical signs: decreased 

weight gains, liver effects.

28-day dermal (rat) NOAEL 1000 (HDT2).

Chronic / Carcinogenicity (rat) NOAEL 107/127 (M/F; HDT). Not 

carcinogenic.

Chronic (dog) NOAEL 52 (HDT).

Carcinogenicity (mouse) NOAEL 358/354 (M/F); (HDT). Not 

carcinogenic.

1M/F stands for males/females.

2HDT stands for the highest dose tested.

The EPA has classified dicamba as “Not Likely to Cause Cancer in Humans” (the most favorable 

among EPA’s cancer categories), and concluded that dicamba is not mutagenic and is not a 

developmental toxin. There was no evidence of behavioral or neurological effects on offspring and, 

therefore, a developmental neurotoxicity study was not required by the EPA.

In the human health risk assessments for dicamba, the EPA employed a chronic Population 

Adjusted Dose (cPAD) of 0.45 mg/kg/day, based on a 100-fold safety factor applied to the 

offspring NOAEL in the multigeneration rat study. For evaluating acute exposures to dicamba, the 

EPA employed an acute Population Adjusted Dose (aPAD) of 1 mg/kg, based on a 300-fold safety 

factor (for use of the LOAEL rather than the NOAEL) applied to the LOAEL in the rat acute 

neurotoxicity study (U.S. EPA 2008a).

Using a dietary exposure model to estimate combined exposures from all presently approved uses, 

including both food and water exposure routes, and assuming that 100% of all labeled crops are 

treated with dicamba and that the resulting foods have tolerance-level residues, total dietary 

exposure reached only 4.4% of the aPAD level and 2.7% of the cPAD level for the general U.S. 

population; and 11% of the aPAD and 6.8% of the cPAD for the most highly exposed 

subpopulations of children 1-2 years old (U.S. EPA 2008a). 

The proposed dicamba use on DT soybean does not require an increase in the soybean seed food 

tolerance. However, Monsanto has requested new tolerances for soybean forage and hay; to support 

the potential feeding of soybean forage and hay to livestock. Monsanto has also requested an 

increase in the cotton seed tolerance to 3 ppm and establishment of a cotton gin by-product 

tolerance of 70 ppm. Since cotton production does not contribute significantly to human dietary 

exposure and the proposed changes to existing dicamba crop tolerances as outlined do not increase 

the livestock dietary burden utilized in the RED assessment, all dietary exposures from the proposed 

dicamba use on DT soybean and DGT cotton are already accounted for in these assessments.

E.4.2 Toxicology of Dicamba Plant and Animal Metabolites 

DT soybean and DGT cotton have been genetically enhanced to express a dicamba metabolizing 

enzyme (dicamba mono-oxygenase). The enzyme catalyzes a mono-oxygenation reaction resulting 

in an oxidative demethylation of dicamba, forming 3,6-dichloro-2-hydroxybenzoic acid, also known 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 719 of 946

as 3,6-dichlorosalicylic acid (DCSA). In the dicamba-treated DT soybean and DGT cotton, 

glucoside conjugates of DCSA were the major plant metabolites. 

Cl OH

Cl

O OH

Figure E-2. Structure of DCSA

DCSA is a known metabolite of dicamba in soil, plants, and livestock. It is presently included in the 

residue expression specified in the food and feed tolerance for dicamba in 40 CFR 180.227(a)(3). 

Therefore, the existing food tolerance for soybean seed includes DCSA residues. 

In the RED, EPA considered that DCSA has structural similarity to dicamba, and concluded that it 

would have similar toxicity to the parent dicamba. Monsanto has conducted and submitted 

additional toxicity studies involving direct dosing with DCSA (U.S. EPA OPP Decision Number 

D432752) to further substantiate the conclusion reached by the EPA in the RED. The results of 

these studies, summarized in Table E-4, can be compared to those of dicamba (Tables E-1 through 

E-3). Monsanto has submitted these studies to the EPA in support of our application to register the 

use of dicamba on DT soybean and DGT cotton. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 720 of 946

Table E-4. Summary of Toxicological Findings from Testing of DCSA

Study 

Systemic Toxicity Endpoint 

(mg/kg body wt/day)

Offspring Toxicity Endpoint 

(if any)

(mg/kg body wt/day)

Acute oral (rat) LD50 2641 (Category III) NA

Developmental (rat) Maternal NOAEL 100 Developmental NOAEL 100

Developmental (rabbit) Maternal NOAEL 25 Developmental NOAEL 65 

(HDT)

Reproduction, 

multigeneration (rat) 

Parental NOAEL 42 (M/F1

combined)

Offspring NOAEL 42

Gene mutation – S.

typhimurium & E. coli 

Not mutagenic NA

In vitro chromosome 

aberration (CHO) 

Aberrations not induced NA

Micronucleus (mouse) Negative NA

Subchronic (90-day) oral 

(Rat) 

NOAEL 362/222 (M/F) NA

Chronic (12-month)(rat) NOAEL 171/206 (M/F). NA

Subchronic (90-day) (dog) NOAEL 50 NA

In Vitro cytogentics 

(human lymphocytes) 

Weakly positive with S9 

activation

NA

In Vivo cytogenetics (rat) Negative NA

Carcinogenicity Ongoing NA

NA denotes Not Applicable.

1M/F stands for males/females. 

Smaller amounts of a glucoside of another known metabolite, 5-dichloro-3,6-dihydroxybenzoic acid 

(3,6-dichlorogentisic acid, DCGA) were also identified in the soybean and cotton metabolism 

studies. Levels of the DCGA glucoside were less than 10% of total DT soybean- and DGT cottoncontained radioactivity. Monsanto conducted a limited set of toxicity studies on DCGA; and has 

provided these studies to EPA to support our application to register dicamba on DT soybean. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 721 of 946

The results of the DCSA and DCGA toxicity studies substantiate the EPA conclusion that dicamba 

metabolites will have similar toxicity to parent dicamba.

E.5 Potential Impact of Dicamba on Human Health

E.5.1 Dicamba Safety Evaluations for Consumers

On the basis of the risk assessments summarized below, EPA has concluded that there is a 

reasonable certainty that the existing uses of dicamba will not pose a risk to consumers, including 

infants and children. 

Dicamba presently has 68 established food and feed pesticide tolerances in the U.S. (40 CFR § 

180.227). Each time EPA reviews an application to add a new food or feed use to the dicamba 

label, the EPA is required by FFDCA to conduct an aggregate risk assessment. This assessment 

considers potential exposure from the proposed new use with all other existing exposures, including 

non-occupational sources of exposure to the pesticide, and must conclude that aggregate exposure 

to the pesticide will be safe as defined by the statute and regulations. Risks associated with potential 

occupational exposure for each new use are considered under the FIFRA standard of no 

unreasonable adverse effects to the environment, which includes humans and workers (hereafter 

referred to as FIFRA unreasonable risk standard). Over the course of numerous reviews, the 

toxicology of dicamba has been extensively studied. Dicamba does not pose any unusual 

toxicological concerns (U.S. EPA, 2009; Durkin and Bosch, 2004; European Commission, 2007a) 

and is classified by EPA as “Not likely to be Carcinogenic to Humans” (U.S. EPA, 2009). PMRA 

and the European Commission have also classified dicamba as non-carcinogenic (PMRA, 2007, 

2008; European Commission, 2007a).

Dietary exposure, as previously stated, is included in the aggregate exposure assessment, and 

considers pesticide residues that may remain on food from crops on which the pesticide is applied 

(pre- or postemergence), as well as any residue in drinking water as a result of pesticide use. Nondietary exposure is also included in this assessment, and includes exposure to the pesticide through 

residential use, such as on lawns, as well as exposure in a recreational context, such as from a golf 

course or sports field. Based on these data, EPA must be able to make a determination of 

reasonable certainty of no harm to human health as required by the FFDCA. At the time that 

dicamba was undergoing reregistration, occupational exposure was not considered as part of the 

aggregate exposure and was evaluated separately under the FIFRA unreasonable risk standard.

In making a determination of whether a reasonable certainty of no harm to human health exists, 

dietary risk assessments are performed that consider both the potential exposure and toxicity of a 

given pesticide. The dietary risk is then described as a percentage of a level of concern. The level of 

concern, which is also referred to as the population adjusted dose (PAD), is the dose (level of 

exposure) predicted to result in no adverse health effects to any human population subgroup, 

including sensitive subgroups, such as infants and children. The PAD may be expressed based on 

acute (aPAD, one day or less) or chronic exposures (cPAD, lifetime exposure). The PAD is the 

reference dose (RfD) for the compound but with any additional safety/uncertainty factors to protect 

sensitive subpopulations, or to address the completeness, quality or reliability of the toxicity data. 

The PAD is an estimate of the amount of daily pesticide exposure to the human population that can 

occur acutely (less than one day) or over a lifetime with a reasonable certainty of no harm to human 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 722 of 946

health.133 An estimated exposure less than 100% of the PAD is below the level of concern for the 

EPA.

The EPA evaluated the potential risks to human health associated with all then-registered dicamba 

uses as part of the reregistration of dicamba, and published the results and conclusion in the 

dicamba RED (U.S. EPA, 2009). Since reregistration, the EPA has approved an additional use on 

sweet corn, and as part of the approval included this new use in an updated dietary risk assessment. 

Since the sweet corn use pattern was within that reviewed during reregistration, EPA determined 

that the ecological and environmental fate assessments did not need to be updated and utilized the 

drinking water concentration from the RED in the updated sweet corn dietary risk assessment. The 

sweet corn use did not result in any noticeable increase in dietary exposure compared to the 

assessment from the RED; therefore, the risk assessment conduced for the dicamba RED is 

representative of all current registered uses of dicamba. EPA has conducted acute and chronic 

dietary (food and water) risk assessments for dicamba based on a theoretical worst case exposure 

estimate. For food, this estimate assumes that dicamba is used on 100 percent of all the crops on 

which the pesticide is currently approved for use. It further assumes that the resulting pesticide 

residues found on all harvested food crops and derived animal food commodities (e.g., meat and 

milk) are at the level of the legally established tolerance (i.e., the maximum allowable pesticide 

residue level). Residues of dicamba are defined as dicamba and its metabolites 5-hydroxy dicamba 

and 3,6-dichlorosalicylic acid (DCSA) in soybean commodities, and as dicamba and DCSA in animal 

food commodities, as currently regulated in 40 CFR § 180.227 (U.S. EPA, 2005a; U.S. EPA, 2005b). 

For water, EPA assumed that dicamba could potentially move offsite to adjacent surface water 

bodies as a result of drift or runoff. EPA also assumed dicamba could move through soil to 

groundwater; however, estimated concentrations in groundwater were significantly lower and 

therefore surface water estimates were used in the worse case dietary assessments. Surface water

estimates were generated with the conservative screening level models SCIGROW and 

PRZM/EXAM using an exaggerated application rate that is 2.8 times higher than the current 1.0 lb 

a.e./A maximum single application rate established in the dicamba RED (U.S. EPA, 2009, U.S. 

EPA, 2005b), and the maximum single application rate proposed for DT soybean and DGT cotton. 

EPA mandated reductions in dicamba use rates as part of the dicamba RED (1 lb a.e./A and 2 lb 

a.e./A for a single application and for annual application, respectively).

The acute PAD for dicamba is 1 mg per kg body weight per day (mg/kg/day), based on an acute 

neurotoxicity study in rats (U.S. EPA, 2009). Based on the worst-case assumptions outlined above, 

the result of the dietary assessment gave a conservative, high-end (95th percentile) estimate of risk, 

which was well below the Agency’s level of concern for both the U.S. population in general and for 

all population subgroups. As shown in Table E-5, when both food and water are combined, infants

were the most highly exposed subgroup with 11% of the aPAD, or acute level of concern, 

consumed. Because even this most highly exposed subgroup consumes a small percentage of the 

acute level of concern for dicamba, EPA concluded there is a reasonable certainty that acute dietary 

exposure to dicamba will not pose a risk to human health, including that of infants and children 

(U.S. EPA, 2009).

 

133 RfD is the current terminology used by EPA; however, earlier EPA risk assessment terminology used the term Acceptable Daily 

Intake (ADI). RfD and ADI are synonymous.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 723 of 946

The chronic PAD for dicamba is 0.45 mg/kg/day, based on a two-generation reproduction study in 

rats (U.S. EPA, 2009). Based on worst-case assumptions outlined above, EPA developed exposure 

estimates for the general U.S. population and the 8 other subpopulations of consumers evaluated by 

EPA; the major subpopulations are summarized in Table E-5. EPA determined that the most highly 

exposed subgroup for chronic dietary exposure (including both food and water) was children aged 1-

2 years old, which consumed 6.6% of the cPAD, or chronic level of concern. Since even the most 

highly exposed subgroup consumes a small percentage of the chronic level of concern, EPA 

concluded there is a reasonable certainty that chronic dietary exposure to dicamba will not pose a 

risk to human health, including that of infants and children (U.S. EPA, 2009).

Table E-5. Summary of Dietary Exposure and Risk for Dicamba: Food and Water

Population 

subgroup

Acute dietary (95th percentile) Chronic dietary

Dietary 

exposure 

(mg/kg/day) % aPAD

Dietary 

exposure 

(mg/kg/day) % cPAD

General U.S. 

population 0.0435 4.4 0.0118 2.6

All infants

(<1 year old)

0.108 11 0.0199 4.4

Children

1-2 years old

0.0756 7.6 0.0297 6.6

Source: EPA 2005b. 

The EPA also conducted an aggregate risk assessment which included dietary exposure (food and 

water) as well as other non-occupational exposures (e.g., from residential uses such as lawns and 

recreational uses such as golf courses or sports fields). For acute and chronic aggregate risk 

assessment, the aggregate exposure is the same as the dietary exposure. EPA does not typically 

aggregate acute dietary exposures with acute non-occupational exposures because it is unlikely that 

high end dietary exposure will occur on the same day as maximum non-occupational exposures (U.S. 

EPA, 2005b). Current residential uses of dicamba do not result in long term residential exposure

scenarios, so chronic aggregate exposure/risk is equal to chronic dietary exposure/risk. Therefore, 

the acute and chronic dietary exposure and risk summarized in Table E-5 also represents the acute 

and chronic aggregate exposure and risk. 

For short-term aggregate risk assessment of dicamba, EPA considered exposures from food, water, 

and residential handling and post-application. As shown in Table E-6, the highest exposed 

individuals in this assessment were adult males mixing, loading and applying dicamba using a hoseend sprayer, resulting in an aggregate exposure of 5.1% of the cPAD, and toddlers playing on 

treated turf which results in an aggregate exposure of 9.7% of cPAD. This short-term risk aggregate 

risk assessment was also considered to be protective of intermediate and long term exposures to 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 724 of 946

dicamba. A large margin of safety exists for exposure to dicamba, even considering all the approved 

food, feed and non-crop uses of dicamba. 

Table E-6. Aggregate (Short-term) Exposure Assessment for Dicamba 

Population

Food + Water 

Exposure 

mg/kg/day

Incidental Oral 

Exposure, 

mg/day

Dermal Dose, 

mg/kg/day

Combined 

Exposure, 

mg/kg/day %PAD

Adult Male -

Handler 0.0128 0 0.0102 0.023 5.1

Adult Male –

Post 

Application 

0.0128 0 0.0037 0.0165 3.7

Child – 1-2 

years 

0.0297 0.0078 0.0062 0.0437 9.7

Source: EPA, 2005b. 

In summary, based on the EPA risk assessments discussed above, there is a reasonable certainty that 

the existing uses of dicamba will not pose a risk to consumers, including infants and children. 

E.5.2 Dicamba – Proposed New Use on DT Soybean and DGT Cotton – General Population 

Including Infants and Children

Applications have been submitted to the EPA to amend Registration Number 524-582 (a 

diglycolamine (DGA) salt formulation) to register a new use pattern for dicamba on DT soybean 

and DGT cotton. A new product based on BAPMA salt of dicamba has also been submitted to 

EPA for use on DT soybean. In support of the new uses of dicamba on DT soybean and DGT 

cotton, mammalian toxicity data on the dicamba metabolites DCSA (3,6-dichlorosalicylic acid) and 

DCGA (3,6-dichlorogentisic acid), and crop metabolism and residue data on dicamba-treated DT 

soybean and DGT cotton have been generated. These data confirm that existing dicamba food

tolerances are sufficient to address any incremental exposure to dicamba resulting from its use on 

DT soybean or DGT cotton. Furthermore, the proposed use patterns for dicamba on DT soybean 

and DGT cotton maintain the presently established maximum single and annual application rates. 

Monsanto has submitted to EPA applications to register the use of dicamba on DT soybean and 

DGT cotton (U.S. EPA OPP Decision Numbers D-432752 and D-467997). The proposed use of 

dicamba on DT soybean and DGT cotton will not result in measurable increases in the exposure to 

dicamba or significant changes in the human health risk assessment. Plant metabolism studies have 

shown that the majority of the dicamba residue found in DT soybean and DGT cotton is DCSA, 

with lesser amounts of 3,6-dichlorogentisic acid (DCGA), 5-hydroxydicamba (5-OH dicamba) and 

parent dicamba (Tables E-7-8). Toxicology studies submitted to EPA have demonstrated that the 

toxicology profiles for both DCSA and DCGA are comparable to that of parent dicamba, and that 

the existing hazard endpoints (RfDs and PADs) for dicamba are adequate to assess the potential 

human health risks from the metabolites as well. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 725 of 946

Studies have shown that the total dicamba residues in soybean seed following application of dicamba 

to DT soybean will be well below the current 10 ppm soybean seed tolerance, an exposure level 

which has been determined as acceptable by EPA. In addition, Monsanto is proposing to establish 

new feed tolerances for soybean forage (45 ppm) and hay (70 ppm), which will allow the feeding of 

forage and hay to livestock. This practice is not presently allowed because the preharvest application 

occurs after the stage where the crop would be useful as forage and hay. Note that the maximum 

residue for forage at 51.2 ppm is above the proposed MRL of 45 ppm. This is due to the way the 

data are distributed and the use of the NAFTA MRL calculator, which is the standard method used 

by EPA to calculate pesticide tolerance levels (U.S. EPA, 2011a). The EPA will perform its own 

calculations based on the data summarized in the table below to establish an appropriate feed 

tolerance for dicamba on soybean forage and hay. 

Table E-8. Residues of Dicamba, DCSA, 5-Hydroxydicamba and DCGA in DT Soybean 

Forage, Hay and Seed

Commodity

PPM

(Expressed as Each Analyte per se)

PPM

(Dicamba Acid Equivalents)

Dicamba DCSA

5-OH 

dicamba DCGA

Total as current definition 

of residue (dicamba + 

DCSA + 5-OH dicamba)

Forage 

Mean 0.342 15.8 <0.006 2.04 17.3

Median 0.068 14.0 <0.005 1.95 15.2

Minimum <0.021 8.34 <0.005 0.359 10.0

Maximum 2.62 47.9 0.010 5.95 51.2

Hay

Mean 0.130 30.1 <0.014 2.68 32.3

Median 0.051 29.8 <0.014 2.02 31.9

Minimum <0.014 11.4 <0.014 0.169 12.2

Maximum 1.16 57.1 <0.014 7.33 61.1

Seed

Mean <0.013 0.055 <0.021 0.032 <0.091

Median <0.013 0.031 <0.021 0.017 <0.065

Minimum <0.013 0.009 <0.021 <0.011 <0.041

Maximum <0.013 0.411 <0.021 0.136 0.471

Human dietary exposure will not increase beyond what has already been evaluated and determined 

acceptable by the EPA because established tolerances for animal food commodities (e.g., meat or 

milk) are sufficient to address livestock consumption of soybean forage or hay. This is because the 

proposed soybean forage and hay tolerances (residues) are lower than existing livestock dietary 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 726 of 946

constituents that could potentially be replaced with soybean forage or hay in the livestock diet (e.g., 

grass forage at 125 ppm could be replaced with soybean forage at 45 ppm). Soybean forage and hay 

are also not common livestock dietary constituents, as concluded by the EPA in its policy to permit 

label restrictions for livestock feeding of soybean forage and hay (U.S. EPA, 1996). 

Studies have been conducted to determine the residues in cottonseed and gin by-products following 

dicamba applications (Table E-9). Based on this data Monsanto has requested a registration from 

U.S. EPA for the expanded use of dicamba on DT soybean, an increase in the dicamba residue 

tolerance from 0.2 ppm to 3 ppm for cottonseed, the establishment of a tolerance of 70 ppm for 

cotton gin by-products, and the inclusion of DCSA in the residue definitions for cottonseed and gin 

by-products. No other revisions to dicamba pesticide residue tolerances are needed including animal 

products such as meat, eggs, or milk.

The existing 0.2 ppm pesticide residue tolerance for cottonseed supporting the current registered 

uses of dicamba on cotton (40 CFR § 180.227) is for the combined residues of parent dicamba and 

its metabolite 5-hydroxy dicamba. Cotton gin by-products, a ruminant feed supplement, have no 

established dicamba tolerance. Studies have shown that the proposed use of dicamba on DGT

cotton results in total residue concentrations of parent dicamba and its metabolites, including DCSA 

and 5-hydroxy dicamba, are less than 3 ppm for cottonseed and less than 70 ppm for gin byproducts. The EPA will perform its own calculations based on the data summarized in the table 

below to establish an appropriate feed tolerance for dicamba on cotton seed and gin by-products.

Table E-9. Residues of Dicamba, DCSA, 5-Hydroxydicamba and DCGA in DGT Cotton 

Seed and Gin By-products

Commodity

PPM

(Expressed as Each Analyte per se)

PPM

(Dicamba Acid Equivalents)

Dicamba DCSA

5-OH 

dicamba DCGA

Total (dicamba + DCSA + 

5-OH dicamba)

Seed 

Mean 0.61 0.08 <0.02 0.05 0.71

Median 0.47 0.06 <0.02 0.03 0.54

Minimum 0.12 0.02 <0.02 0.02 0.17

Maximum 1.42 0.27 0.002 0.14 1.72

Gin By-Products

Median 14.9 4.50 <0.04 2.41 19.7

Minimum 3.13 1.78 <0.04 0.45 5.06

Maximum 23.0 6.17 <0.04 4.14 29.6

Furthermore, since existing dicamba food tolerances (soybean seed and animal by-products) are 

inclusive of dicamba exposures arising from its use on DT soybean, the most recent EPA dietary 

and aggregate risk assessments for dicamba also address exposure from the proposed use in DT 

soybean. As discussed in the DGT Cotton Petition and Appendices H and I to this Environmental 

Report, the only human food currently produced from cottonseed is refined, bleached, and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 727 of 946

deodorized (RBD) oil, and to a smaller extent, linters so there is no direct consumption of 

cottonseed or gin by-products. Therefore, these risk assessments demonstrate that there is a 

reasonable certainty that the use of dicamba on DT soybean or DGT cotton, together with all other 

approved uses of dicamba, will not pose a risk to human health, including that of infants and 

children. While the use of dicamba is expected to increase as a result of the availability of DT 

Soybean and DGT cotton integrated into the glyphosate-tolerant systems, the risks associated with 

the new uses have been adequately assessed by EPA through the risk assessment conducted as part 

of the dicamba RED. Lastly, EPA will review and confirm the acceptability of dietary exposure of 

dicamba residues on DT soybean and DGT cotton as part of the review of our pending 

applications.

E.5.3 Dicamba Safety Evaluation for Applicator 

Other potential impacts considered by EPA in its human health assessment are occupational

exposure of the pesticide handler/applicator, and post-application exposure resulting from re-entry 

to treated fields or areas. The occupational exposure scenarios evaluated by the EPA as a part of the 

dicamba RED are also applicable to the proposed use of dicamba on DT soybean and DGT cotton 

(U.S. EPA, 2005b; U.S. EPA, 2005c). 

Using exposure data from the Pesticide Handler Exposure Database (PHED), Outdoor Residential 

Exposure Task Force (ORETF), and California Department of Pesticide Regulations, the EPA 

assessed short-term and intermediate-term occupational handler and post-application exposures. 

Handler exposure scenarios included mixer-loader, applicator and flagger activities. When exposure 

assumptions included the wearing of chemical resistant gloves during mixer/loader operations 

involving liquids required by dicamba product labeling, all occupational handler and post-application 

re-entry scenarios exhibited margins of exposure greater than 100 and did not exceed the EPA level 

of concern (U.S. EPA, 2009). The use of dicamba on DT soybean and DGT cotton does not pose 

any new exposure considerations for workers beyond those which have been previously evaluated by 

EPA as part of the dicamba RED. Therefore the use of dicamba on DT soybean and DGT cotton 

will not pose a risk to agricultural workers.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 728 of 946

References for Appendix E

Durkin, P. and S. Bosch. 2004. Dicamba - Human health and ecological risk assessment - Final 

report. SERA TR 04-43-17-06d. U.S. Department of Agriculture, Forest Service, Washington, D.C. 

http://www.fs.fed.us/foresthealth/pesticide/pdfs/112404_dicamba.pdf Accessed May 26, 2010.

European Commission. 2007a. Draft Assessment Report, Volume 3, Annex B6: Toxicology and 

metabolism. Council Directive 91/414/EEC, EU Review Programme.

European Commission. 2007b. Draft Assessment Report, Volume 3, Annex B9: Ecotoxicology. 

Council Directive 91/414/EEC, EU Review Programme.

European Commission. 2008. Review report for the active substance dicamba, Finalised in the 

Standing Committee on the Food Chain and Animal Health at its meeting on 14 March 2008 in view 

of the inclusion of dicamba in Annex I of Directive 91/414/EEC. European Commission, Health 

and Consumer Protection Directorate-General, Paris, France.

PMRA. 2007. Re-evaluation – dicamba. The Use of Dicamba in Agricultural and Industrial Sites. 

Pest Management Regulatory Authority, Health Canada. Ottawa, Canada.

PMRA. 2008. Re-evaluation – dicamba. Pest Management Regulatory Authority, Health Canada. 

Ottawa, Canada.

U.S. EPA. 1996. Residue Chemistry Test Guidelines, OPPTS 860.1000 Background. Office of 

Prevention, Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington, 

DC.

U.S. EPA. 2005a. Dicamba. Residue Chemistry Considerations for the Reregistration Eligibility 

Decision (RED) Document. Summary of Analytical Chemistry and Residue Data. DP Number 

D317703 (Memorandum, C. Olinger and W. Phang, September 13). Health Effects Division, Office 

of Prevention, Pesticides and Toxic Substances, U.S. Environmental Protection Agency, 

Washington, DC.

U.S. EPA. 2005b. Dicamba: HED Chapter of the Reregistration Eligibility Decision Document, 

Phase 1. PC Code 029801; DP Barcode: D317720 (Memorandum, C. Olinger and Y. Yang, 

September 13). Health Effects Division, Office of Prevention, Pesticides and Toxic Substances, 

U.S. Environmental Protection Agency, Washington, DC.

U.S. EPA. 2005c. Dicamba: Occupational and Residential Exposure and Risk Assessment for the 

Reregistration Eligibility Decision (RED) Document. PC Code 029801, DP Barcode D317701 

(Memorandum, T.C. Dole, September 6). Health Effects Division, Office of Prevention, Pesticides 

and Toxic Substances, U.S. Environmental Protection Agency, Washington, DC.

U.S. EPA. 2008a. Dicamba Pesticide Tolerance. U.S. Environmental Protection Agency, 

Washington, D.C. Vol. 73, No. 64.

U.S. EPA. 2008b. Aldicarb, Ametryn, 2,4-DB, Dicamba, Dimethipin, Disulfoton, Diuron, et al.; 

Proposed Tolerance Actions. U.S. Environmental Protection Agency, Washington, D.C. Federal 

Register Vol. 73, No. 108.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 729 of 946

U.S. EPA. 2008c. Aldicarb, Ametryn, 2,4-DB, Dicamba, Dimethipin, Disulfoton, Diuron, et al.; 

Tolerance Actions. U.S. Environmental Protection Agency, Washington, D.C. Vol. 73, No. 186.

U.S. EPA. 2009. Reregistration Eligibility Decision (RED) for Dicamba and Associated Salts. Case 

No. 0065. U.S. Environmental Protection Agency Office of Prevention, Pesticides and Toxic 

Substances, Special Review and Reregistration Division, Washington, D.C.

U.S. EPA. 2010. Registration Review: Conventional Cases Schedule: 2010-2013. U.S. 

Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances. June 7, 

2010. http://www.epa.gov/oppsrrd1/registration_review/2010-13-conventional.pdf Accessed June 

12, 2010.

U.S. EPA. 2011a. NAFTA maximum residue levels (MRL) calculator. U.S. Environmental 

Protection Agency, Washington, D.C. http://www.epa.gov/oppfead1/international/naftatwg/mrlcalculator.html Accessed February 22, 2012.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 730 of 946

APPENDIX F: POTENTIAL IMPACTS ON WILDLIFE, PLANTS, ECOSYSTEMS, 

AND THREATENED OR ENDANGERED SPECIES FROM DICAMBA USAGE
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 731 of 946

Table of Contents

F.1. Introduction............................................................................................................................................740

F.2. Dicamba Product Use and General Approach to Risk Assessment ..............................................740

F.2.1. Background – Dicamba........................................................................................................740

F.2.2. Dicamba Application Rate and Timing..............................................................................741

F.2.3. Physical and Chemical Properties of Dicamba .................................................................743

F.2.4. Risk Presumptions and Exposure Analysis.......................................................................744

F.2.5. Exposure Models and Methods..........................................................................................745

F.2.6. Literature Review...................................................................................................................746

F.2.7. Estimates of Foliar Residues and Residue Decline ..........................................................748

F.2.7.1. Default Residues...................................................................................................748

F.2.7.2. Grass Forage Residues.........................................................................................749

F.2.7.3. Broadleaf Plant Forage Residue Refinements..................................................750

F.2.7.4. Estimates of Dicamba Residues in Wildlife Food Items................................750

F.2.8. Estimates of Pond Water Concentrations.........................................................................753

F.2.8.1. DT Soybean...........................................................................................................753

F.2.8.2. DGT Cotton .........................................................................................................754

F.3. Assessment of Non-Target Species.....................................................................................................756

F.3.1. Avian Analysis........................................................................................................................756

F.3.1.1. Avian Toxicity Summary .....................................................................................756

F.3.1.2. Avian Exposure Estimates..................................................................................759

F.3.1.3. Avian Risk Quotient Calculations......................................................................763

F.3.1.4. Avian Discussion and Conclusions....................................................................766

F.3.2. Wild Mammal Analysis.........................................................................................................767

F.3.2.1. Wild Mammal Toxicity Summary.......................................................................767
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 732 of 946

F.3.2.2. Wild Mammal Exposure Estimates ...................................................................769

F.3.2.3. Wild Mammal Risk Quotient Calculations .......................................................772

F.3.2.4. Wild Mammal Discussion and Conclusions.....................................................775

F.3.3. Terrestrial Invertebrate Analysis.........................................................................................776

F.3.3.1. Honeybee Toxicity Summary..............................................................................776

F.3.3.2. Honeybee Exposure Estimates ..........................................................................776

F.3.3.3. Honeybee Risk Quotient Calculations ..............................................................776

F.3.3.4. Honeybee Discussion and Conclusions............................................................777

F.3.4. Aquatic Animal Analysis ......................................................................................................777

F.3.4.1. Aquatic Animal Toxicity Summary....................................................................777

F.3.4.2. Aquatic Animal Exposure Estimates.................................................................778

F.3.4.3. Aquatic Risk Quotient Calculations...................................................................778

F.3.4.4. Aquatic Animal Analysis Summary and Conclusions .....................................780

F.3.5. Aquatic Plant Analysis..........................................................................................................780

F.3.5.1. Aquatic Plant Toxicity Summary........................................................................780

F.3.5.2. Aquatic Plant Exposure Estimates.....................................................................780

F.3.5.3. Aquatic Plant Risk Quotient Calculations.........................................................781

F.3.5.4. Aquatic Plant Analysis Summary and Conclusions.........................................782

F.3.6. Terrestrial and Semi-Aquatic Plant Analysis.....................................................................782

F.3.6.1. Terrestrial and Semi-Aquatic Plant Toxicity Summary...................................782

F.3.6.2. Terrestrial and Semi-Aquatic Plant Exposure Estimates................................786

F.3.6.3. Terrestrial and Semi-Aquatic Plant Risk Quotient Calculations....................786

F.3.6.4. Terrestrial and Semi-Aquatic Plant Summary and Conclusions....................788

F.4. Threatened and Endangered Species Analysis for Dicamba, DT Soybean and DGT 

Cotton ................................................................................................................................................790
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 733 of 946

F.4.1. Monsanto’s Technical Analysis Follows EPA’s Guidance, and Relies on the 

“Best Information Available” Regarding Threatened and Endangered Species.......791

F.4.2. Reports Submitted.................................................................................................................794

F.4.3. Effects on Threatened or Endangered Plant Species From Dicamba Use on 

DT Soybean.........................................................................................................................796

F.4.3.1. Endangered Species Exposure and Effects Analysis ......................................796

F.4.3.2. County-Level Analysis: Co-occurrence of Listed Plant Species in 

Crop Production Areas........................................................................................799

F.4.3.3. Sub-County Plant Species Observations versus Land Use Proximity 

Analysis...................................................................................................................801

F.4.3.4. Sub-county Areas for Potential Use Limitation and Mitigation 

Measures.................................................................................................................804

F.4.3.5. Conclusions...........................................................................................................806

F.4.4. Effects on Threatened or Endangered Animal Species From Dicamba Use on 

DT Soybean.........................................................................................................................807

F.4.4.1. Endangered Species Exposure and Effects Analysis ......................................807

F.4.4.2. County-level Analysis: Co-occurrence of Listed Species in Crop 

Production Areas ..................................................................................................814

F.4.4.3. Sub-County Animal Species Observations versus Land Use 

Proximity Analysis ................................................................................................816

F.4.4.4. Species-specific Risk Quotient Calculations.....................................................817

F.4.4.5. Indirect Effects on Threatened and Endangered Species of Other 

Taxa Resulting from Direct Effects on Plant Species. ....................................821

F.4.4.6. Conclusions...........................................................................................................822

F.4.5. Impact on Threatened or Endangered Plant Species from Dicamba Use on 

DGT Cotton........................................................................................................................822

F.4.5.1. Endangered Species Exposure and Effects Analysis ......................................822

F.4.5.2. County Level Analysis: Co-occurrence of Listed Plant Species in 

Crop Production Areas........................................................................................824

F.4.5.3. Sub-County Plant Species Observations Versus Land Use Proximity 

Analysis...................................................................................................................825
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 734 of 946

F.4.5.4. Sub-county Areas for Potential Use Limitation and Mitigation 

Measures.................................................................................................................831

F.4.5.5. Conclusion.............................................................................................................832

F.4.6. Impact on Threatened or Endangered Animal Species from Dicamba Use on 

DGT Cotton........................................................................................................................834

F.4.6.1. Endangered Species Exposure and Effects Analysis ......................................835

F.4.6.2. County-level Analysis: Co-occurrence of Listed Species in Crop 

Production Areas ..................................................................................................842

F.4.6.3. Sub-County Animal Species Observations versus Land Use 

Proximity Analysis ................................................................................................843

F.4.6.4. Species-specific Risk Quotient Calculations.....................................................845

F.4.6.5. Indirect Effects on Threatened and Endangered Species of Other 

Taxa Resulting from Direct Effects on Plant Species.....................................849

F.4.6.6. Conclusions...........................................................................................................850

F.4.7. Potential for GE Plant to Affect Threatened or Endangered Species..........................850

F.4.8. Potential for DT Soybean to Affect Threatened or Endangered Species ....................851

F.4.9. Potential for DGT Cotton to Affect Threatened or Endangered Species...................853
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 735 of 946

Tables and Figures

Figure F-1. 3,6-dichloro-2-methoxybenzoic acid (Dicamba) (CAS No. 1918-00-9) ...........................741

Table F-1. Conversion Factors for Dicamba Acid and Dicamba Salts ................................................741

Table F-2. Dicamba Application Rates for DT-Soybean........................................................................742

Table F-3. Dicamba Application Rates for Cotton Containing the Dicamba Tolerance Trait.........742

Figure F-2. Soybean Growth Stages and Dicamba Window of Application.......................................743

Figure F-3. Cotton Growth Stages and Dicamba Window of Application .........................................743

Table F-4. Environmental Fate and Physical Properties of Dicamba ..................................................744

Table F-5. Summary of EPA Risk Presumptions for Ecological Effects Assessments.....................745

Table F-6. Summary of Models or Methods Used to Estimate Exposure of Each Taxon to 

Dicamba.............................................................................................................................................746

Table F-7. Summary of Dicamba Residue Half-Life in Pasture Grasses and Wheat.........................749

Table F-8. T-REX Default Residue Values for Wildlife Food Items...................................................750

Table F-9. Dicamba Residue Values for Wildlife Food Items Considered in the Risk 

Quotient Calculations for Birds and Mammal .............................................................................751

Table F-10. Summary of Dicamba Concentrations in Pond Water Estimated by GENEEC..........753

Table F-11. Dicamba Concentrations in Pond Water Estimated by GENEEC and 

PRZM/EXAMS...............................................................................................................................754

Table F-12. Summary of Dicamba Concentrations in Pond Water Estimated by GENEEC..........755

Table F-13. Dicamba Concentrations in Pond Water Estimated by GENEEC and 

PRZM/EXAMS...............................................................................................................................755

Table F-14. EPA Levels of Concern and Toxicity Endpoints for Birds Used in the Analysis.........756

Table F-15. Adjusted LD50 values based on body weight.......................................................................756

Table F-16. Avian Acute Oral Toxicity for Dicamba Acid and Dicamba Salts..................................757

Table F-17. Avian Subacute Dietary Studies for Dicamba Acid and Dicamba Salts..........................758

Table F-18. Avian Reproduction Toxicity Endpoints for Dicamba Acid............................................759
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 736 of 946

Table F-19. Avian: Estimated Environmental Concentrations Using Kenaga Residues and 

Foliar Half-Life of 35 Days (assuming a 6-day interval maximum use pattern for 

DGT cotton or DT soybean).........................................................................................................760

Table F-20. Avian: Estimated Environmental Concentrations Using Kenaga Residues and 

Refined Foliar Half-Life of 5.63 Days (assuming a 6-day interval maximum-use 

pattern for DGT cotton or DT soybean).....................................................................................761

Table F-21. Avian: Estimated Environmental Concentrations Using Maximum Measured 

Residue Estimates (short and tall grass) and Refined Foliar Half-Life of 5.63 Days 

(assuming a 6-day interval maximum use pattern for DGT cotton or DT soybean).............762

Table F-22. Avian: Estimated Environmental Concentrations Using Refined Maximum 

Measured Residue Estimates (90th centile value for short and tall grass) and Refined 

Foliar Half-Life of 5.63 Days (assuming a 6-day interval maximum use pattern for 

DGT cotton or DT soybean).........................................................................................................763

Table F-23. Avian: Risk Quotients Using Kenaga Residues and Foliar Half-Life of 35 Days 

(assuming a 6-day interval maximum use pattern for DGT cotton or DT soybean).............764

Table F-24. Avian: Risk Quotients Using Kenaga Residues and Refined Foliar Half-Life of 

5.63 Days (assuming a 6-day interval maximum-use pattern for DGT cotton or DT 

soybean).............................................................................................................................................765

Table F-25. Avian: Risk Quotients Using Maximum Measured Residues for Vegetation 

(short and tall grass) and Refined Foliar Half-Life of 5.63 Days (assuming a 6-day 

interval maximum use pattern for DGT cotton or DT soybean).............................................766

Table F-26. Mammals: EPA Levels of Concern and Toxicity Endpoints Used in the 

Analysis..............................................................................................................................................767

Table F-27. Adjusted toxicity values based on body weight ...................................................................768

Table F-28. Mammalian Acute Toxicity for Dicamba Acid...................................................................768

Table F-29. Mammalian Subchronic and Developmental/Reproductive Toxicity for 

Dicamba Acid ...................................................................................................................................768

Table F-30. Mammals: Estimated Environmental Concentrations Using Kenaga Residues & 

Foliar Half-Life of 35 Days (assuming a 6-day interval maximum use pattern for 

DGT cotton or DT soybean).........................................................................................................769

Table F-31. Mammals: Estimated Environmental Concentrations Using Kenaga Residues 

and Refined Foliar Half-life of 5.63 Days (assuming a 6-day interval maximum-use 

pattern for DGT cotton or DT soybean).....................................................................................770

Table F-32. Mammals: Estimated Environmental Concentrations Using Maximum 

Measured Residues (short and tall grass) and Refined Foliar Half-life of 5.63 Days 

(assuming a 6-day interval maximum-use pattern for DGT cotton or DT soybean) ............771
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 737 of 946

Table F-33. Mammals: Estimated Environmental Concentrations Using Refined Maximum 

Measured Residues (90th centile value for short and tall grass) and Refined Foliar 

Half-life of 5.63 Days (assuming a 6-day interval maximum-use pattern for DGT 

cotton or DT soybean)....................................................................................................................772

Table F-34. Mammals: Risk Quotients Using Kenaga Residues and Foliar Half-Life of 35 

Days (assuming a 6-day interval maximum use pattern for DGT cotton or DT 

soybean).............................................................................................................................................773

Table F-35. Mammals: Chronic Risk Quotients Using Kenaga Residues and Refined Foliar 

Half-Life of 5.63 Days (assuming a 6-day interval maximum-use pattern for DGT 

cotton or DT soybean)....................................................................................................................774

Table F-36. Mammals: Chronic Risk Quotients Using Maximum Measured Residues (short 

and tall grass) and Refined Foliar Half-life of 5.63 Days (assuming a 6-day interval 

maximum-use pattern for DGT cotton or DT soybean)...........................................................774

Table F-37. Mammals: Chronic Risk Quotients Using Refined Maximum Measured 

Residues (90th centile value for short and tall grass) and Refined Foliar Half-life of 

5.63 Days (assuming a 6-day interval maximum-use pattern for DGT cotton or DT 

soybean).............................................................................................................................................775

Table F-38. Non-Target Invertebrates - Acute Contact Toxicity to Dicamba....................................776

Table F-39. Risk Quotients for Non-target Invertebrates (assuming a 6-day interval ve 

maximum use pattern for DGT cotton or DT soybean)...........................................................777

Table F-40. Toxicity of Dicamba and Dicamba DGA salt to Aquatic Animals ..................................778

Table F-41. Tier I Risk Quotients for Aquatic Animals based on GENEEC Exposure 

Estimates for DGT Cotton and DT Soybeans............................................................................779

Table F-42. Tier II Risk Quotients for Aquatic Animals based on PRZM/EXAMS 

Exposure Estimates using a 6-day interval maximum use pattern for DGT coton (1.0 

lb/A + 0.5 lb/A + 0.5 lb/A)..........................................................................................................779

Table F-43. Tier II Risk Quotients for Aquatic Animals based on PRZM/EXAMS 

Exposure Estimates using the maximum use pattern for DT soybean (1.0 lb/A + 0.5

lb/A + 0.5 lb/A) ..............................................................................................................................780

Table F-44. Non-Target Aquatic Plant Toxicity of Dicamba Acid.......................................................780

Table F-45. Tier I Risk Quotients for Aquatic Plants based on GENEEC Exposure 

Estimates for DGT Cotton and DT Soybean. ............................................................................781

Table F-46. Tier II Risk Quotients for Aquatic Plants Based on PRZM/EXAMS Exposure 

Estimates using a 6-day interval maximum use pattern for DT Soybean and DGT 

Cotton (1.0 lb/A + 0.5 lb/A + 0.5 lb/A) ....................................................................................782
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Table F-47. Comparison of non-target plant testing methodology........................................................783

Table F-48. 21-Day Seedling Emergence Endpoints for Dicamba DGA Salt....................................785

Table F-49. 21-Day Vegetative Vigor Endpoints for Dicamba DGA Salt..........................................785

Table F-50. Dicamba: TerrPlant EECs for Terrestrial and Semi-Aquatic Plants..............................786

Table F-51. Tier I Risk Quotients for Terrestrial and Semi-aquatic Plants for a 1 lb a.e./A 

Application........................................................................................................................................787

Table F-52. Tier I Risk Quotients for Terrestrial and Semi-aquatic Plants at the 0.5 lb a.e./A 

Application........................................................................................................................................787

Table F-53. Summary Statistics for Detected Dicamba Concentrations Reported in Water 

Quality Monitoring Databases........................................................................................................789

Table F-54. Summary Statistics for Detected Dicamba Concentrations (μg a.e./L) in Surface 

Water in Major Corn Growing States (April – July sampling dates) ........................................789

Table F-55. EPA Levels of Concern for Threatened and Endangered Plant Species 

(USEPA, 2004) .................................................................................................................................798

Table F-56. Summary of Species Determinations for this Analysis......................................................800

Table F-57. Numbers of counties, listed plant species, and observations involved in the 

analysis for DT-soybeans at major steps in the analysis.............................................................807

Table F-58. EPA Levels of Concern for Threatened and Endangered Species (USEPA, 

2004)...................................................................................................................................................809

Table F-60. Risk Quotients for Chronic Exposure for Mammalian Species Based on 

Dicamba-Specific Residue Values and DT50. ...............................................................................812

Table F-61. Risk Quotients for Acute Exposure to Birds Using Maximum Measured 

Dicamba Residues and Dicamba-specific Residue Decline Values..........................................813

Table F-62. EPA Levels of Concern for Threatened and Endangered Plant Species 

(USEPA, 2004) .................................................................................................................................824

Table F-63. Summary of Species Determinations for this Analysis (from Frank and 

Kemman, 2013)................................................................................................................................825

Table F-64. Results of Proximity Analysis Presented (by Region).........................................................829

Table F-65. Results of Proximity Analysis Presented (by State)............................................................830

Table F-66. Numbers of counties, listed plant species, and observations involved in the 

analysis for cotton with the DT trait at major steps in the analysis..........................................834
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Table F-67. EPA Levals of Concern for Threatened and Endangered Species (US EPA, 

2004)...................................................................................................................................................836

Table F-68. Comparison of Default Kenaga Residues and Dicamba-specific Residues in 

Food-Items........................................................................................................................................838

Table F-69. Risk Quotients for Chronic Exposure for Mammalian Species Based on 

Dicamba-Specific Residue Values and DT50. ...............................................................................839

Table F-70. Risk Quotients for Acute Exposure to Birds Using Maximum Measured 

Dicamba Residues and Dicamba-specific Residue Decline Values..........................................840
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F.1. Introduction

This Appendix evaluates the potential for exposure and effects of low-volatility dicamba

formulations, including diglycolamine salt formulations, to wildlife, plants, ecosystems and 

threatened and endangered species from the increased use of dicamba on dicamba-tolerant soybean 

(DT soybean) and dicamba and glufosinate-tolerant cotton (DGT cotton). The analysis below 

follows in large measure EPA’s Overview of the Ecological Risk Assessment Process in the Office 

of Pesticide Programs, U.S. EPA: Endangered and Threatened Species Effects Determinations 

(U.S. EPA 2004) and EPA’s Environmental Fate and Ecological Risk Assessment for dicamba (U.S. 

EPA 2005), from which the majority of the environmental fate input parameters and toxicity 

endpoints were taken to determine Risk Quotient (RQ) values for this analysis. Available toxicity 

data for the dicamba diglycolamine (DGA) salt were also considered, where available. 

F.2. Dicamba Product Use and General Approach to Risk Assessment

F.2.1. Background – Dicamba 

Dicamba (Figure F-1) is a broad-spectrum, systemic herbicide with activity on a wide range of 

annual and perennial plants. It was first registered in the United States in 1967 and is widely used in 

agricultural, industrial and residential settings. Dicamba controls annual, biennial and perennial 

broadleaf weeds in crops and grasslands, and it is used to control brush and bracken in pastures. In 

combination with a phenoxyalkanoic acid or other herbicide(s), dicamba is used in pastures, 

rangeland, and non-crop areas, such as fence-rows and roadways, to control weeds. Dicamba is a 

benzoic acid herbicide similar in structure and mode of action to phenoxy herbicides. Typical 

terrestrial application methods consist of ground and aerial spray, however application to soybean 

and cotton containing the dicamba tolerance trait will be limited to ground application under the 

proposed FIFRA label, which is currently pending before EPA. Additional requirements on the 

proposed FIFRA label (e.g. nozzle selection, wind speed, ground speed, and boom height) and/or 

any other measures imposed by EPA will minimize off-field exposure to nontarget organisms from 

the use of dicamba on soybean and cotton with the DT trait (see Appendix D for additional details). 

Dicamba is formulated primarily as a salt in an aqueous solution, although the acid form may be 

used in some cases. Dicamba salts that are or have been used in commercial herbicide formulations 

include dicamba dimethylamine salt (DMA), dicamba sodium salt (Na+), dicamba diglycolamine salt 

(DGA), dicamba isopropylamine salt (IPA), and dicamba potassium salt (K+). Table F-1 gives 

conversion factors to convert the various salt forms of dicamba into an equivalent amount of the 

acid form (expressed as acid equivalents, or a.e.) of dicamba. Monsanto has requested the use of 

dicamba with DT soybean and DGT cotton only for low volatility salt formulations of dicamba.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 741 of 946

Figure F-1. 3,6-dichloro-2-methoxybenzoic acid (Dicamba) (CAS No. 1918-00-9)

Unless stated otherwise, the information and calculations presented in this document are based on 

the amount of active ingredient as acid equivalents (a.e.) rather than as the salt form.

Table F-1. Conversion Factors for Dicamba Acid and Dicamba Salts

Form Molecular Weight Acid Equivalent Conversion 

Factora

dicamba acid 221 ----

dimethylamine salt of dicamba 266 0.831

sodium salt of dicamba 243 0.909

potassium salt of dicamba 259.1 0.853

diglycolamine salt of dicamba 326.18 0.678

a To get the equivalent amount of the acid (a.e., acid equivalent), multiply the amount of the dicamba salt by this factor.

F.2.2. Dicamba Application Rate and Timing

The dicamba tolerance trait allows for application of dicamba to occur from any time before 

soybean emergence up to R1/R2 (first reproductive flowering stages) growth stage. The dicamba 

tolerance trait allows for application of dicamba to cotton with the DT trait to occur preplant with 

no planting interval, pre-emergence or post-emergence up to 7 days before harvest. Application 

rates considered in this analysis (which are the maximum rates permissible under the proposed 

FIFRA label) are set forth in Tables F-2 and F-3:
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Table F-2. Dicamba Application Rates for DT-Soybean

Maximum Application Rates

Combined total per year for all applications 2.0 lb dicamba a.e. per acre

Total of all Preplant, At-Planting, and Pre-emergence 

applications

1.0 lb a.e. per acre

Total of all In-crop applications from emergence up to first 

reproductive flowering stages (R1/R2 stage soybeans) a

1.0 lb a.e. per acre

Maximum In-crop, single application 0.5 lb a.e. per acre

a

In-crop applications are only permitted from emergence to R1/R2 growth stage.

Table F-3. Dicamba Application Rates for Cotton Containing the Dicamba Tolerance Trait

Maximum Application Rates

(lb dicamba a.e./A)

Combined total per year for all applications 2.0

Total of all Preplant, At-Planting, and Pre-emergence applications 1.0

Total of all In-crop applications from emergence up to 7 days preharvest a

 If no application prior to emergence: 

 With application prior to emergence:

2.0

2.0 minus Prior to Emergence 

amount

Maximum In-crop, single application 0.5

a In-crop applications are permitted from emergence to seven days before harvest.

For DT soybeans, applications can occur at any or all of these plant growth stages combined. For incrop applications the proposed label recommends one application between emergence and V3

growth stage when weeds are small and actively growing, and, if needed, a second application up to

the R1/R2 growth stage to control new flushes of weeds. This analysis considers only ground

applications of dicamba, which are required under the proposed FIFRA label, to DT-soybeans, and

considers that interval between applications will be at least 6 days.

For DGT cotton, applications can occur at any or at several of these plant growth stages. In-crop 

applications can be made from emergence up to 7 days prior to harvest when weeds are small and 

actively growing. Sequential applications with at least a 7 day interval between applications may be 

necessary to control new flushes of weeds. This analysis considers only ground applications of 

dicamba to cotton with the DT trait since aerial applications will not be permitted, and considers 

that the interval between applications will be at least 6 days which is more conservative than the 7-

day interval currently required on the proposed label.

Figures F-2 and F-3, respectively, give a graphical illustration of the soybean and cotton growth

stages and the application window that is proposed.
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Figure F-2. Soybean Growth Stages and Dicamba Window of Application

Figure F-3. Cotton Growth Stages and Dicamba Window of Application

F.2.3. Physical and Chemical Properties of Dicamba

A summary of the chemical and physical properties of dicamba used in this analysis is given in Table 

F-4. These values were taken from the EPA Environmental Fate and Effects Division Environmental Fate 

and Ecological Risk Assessment for the Reregistration of Dicamba and Dicamba Sodium, Potassium, Diglycoamine, 

Dimethylamine and Isopropylamine Salts (U.S. EPA 2005). These properties were used to calculate 

environmental exposures via the water, soil, or foliage as appropriate.

*

Harvest First 

bloom

Mid

bloom

Preemergence

Postemergence

*

*

*

Dicamba application window

Pre: Up to 1 lb/A

Post: Up to four 0.5 lb/A and 7 days preharvest

(2 lb/A/yr maximum)

*
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Table F-4. Environmental Fate and Physical Properties of Dicamba

CAS Name 3,6-dichloro-2-methoxybenzoic acid 

IUPAC Name 3,6-dichloro-o-anisic acid 

CAS No 

(Chemical Abstracts Service Registry 

Number)

1918-00-9 

Empirical Formula C8H6Cl2O3

Molecular Weight 221.04 

Common Name Dicamba 

Chemical Family Benzoic acid 

Color/Form Colorless crystals 

Odor Odorless 

Melting Point 114 – 116°C 

Flash Point 199°C 

Relative Density 1.57 g/ml at 25°C 

Water Solubility 6100 mg/L 

Vapor Pressure 3.41 x10-05 torr (25°C) 

Henry’s Law Constant 1.79 x 10-8

pKa 1.87 

Kd(Freundlich) mL/g 0.07 (sandy loam), 0.1 (clay loam), 0.16 (loam), 

0.21 (loam), 0.53 (silt loam) 

Koc (mL/g) 3.45 (clay loam), 7.27 (loam), 

17.5 (loam and sandy loam), 21.1 (silt loam) 

Soil volatilization 2.91 x 10-4to 4.97 x 10-4 ug/cm2/hr at 0.5 lb a.i./A

Field dissipation half-life (DGA salt) 3.0 days (LA silt loam), 3.29 (NC loam sand), 12.9 (IN loam)

(DMA salt) 4.4 – 19.8 days

Anaerobic soil half-life 141 days

Aerobic soil half-life 6 days

Soil photolysis Approx 20% at 30 days, 25 C (continuous irradiation)

Aqueous hydrolysis Stable

Aqueous photolysis half-life 38.1 days (continuous irradiation)

Anaerobic aquatic half-life 141 days

Aerobic aquatic half-life (days) 20.2 days (flooded loam), 24.3 (non-linear fit)

F.2.4. Risk Presumptions and Exposure Analysis

Table F-5 summarizes the risk presumptions as established by the U.S. EPA for endangered species 

assessments. Both acute risk and chronic risk are assessed for birds, wild mammals, and aquatic 

animals. For plants (aquatic, terrestrial, and semi-aquatic) and for terrestrial invertebrates, EPA only 

assesses acute risk. Consistent with the approach described in the Overview of the Ecological Risk 

Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency, Endangered and 

Threatened Species Effects Determinations (USEPA, 2004) (Overview Document), the potential for effects 

on a group of species from exposure is assessed by comparing a risk quotient (RQ) to EPA’s Level 

of Concern (LOC). The RQ is calculated by dividing the estimated environmental concentration 

(EEC) by the appropriate toxicity value as indicated in Table F-5. The LOC is a fractional value that 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 745 of 946

defines how much lower the exposure value (EEC) must be, compared to the toxicity value, for the 

species group to be eliminated from concern at the screening level. That is, if the RQ value is less 

than the LOC, it can be concluded that risk to the species group from exposure can be excluded 

from concern because of the conservative nature of the screening-level assessment assumptions, 

and, therefore, a conclusion of no effect on the group of species can be reached.134 If the RQ value 

exceeds the LOC, then additional refinements may be performed in order to assess whether risk to 

the taxa can be excluded from concern and, therefore, whether there would be any effect on the 

taxa. 

Table F-5. Summary of EPA Risk Presumptions for Ecological Effects Assessments

Wildlife Category

Acute Risk Chronic Risk

Risk Quotient 

Formula

Level of 

Concern 

(LOC)

Risk Quotient 

Formula

Level of 

Concern (LOC)

Direct Effects to Non-Endangered Species

Aquatic Animals EEC/EC50 0.5 EEC/NOEC 1.0

Terrestrial Animals EEC/LD50 0.5 EEC/NOEC 1.0

Terrestrial Invertebrates EEC/ LD50 0.5 -- Not assessed

Aquatic Plants 

(vascular and non-vascular)

EEC/EC50 1.0 -- Not assessed

Terrestrial Plants EEC/EC25 1.0 -- Not assessed

EEC: Estimated environmental concentration. 

LC50/EC50: Exposure concentration resulting in death or immobilization of 50% of the test animals or 50% inhibition of a growth 

parameter for test plants.

LD50: Dose resulting in death of 50% of the test organisms.

NOEC: no-observed-effect concentration.

F.2.5. Exposure Models and Methods

The potential exposure of each taxon evaluated in this analysis for dicamba was determined using 

the standard EPA models (current versions at the time of preparation) or methods as described in 

Table F-6.

 

134 Throughout the rest of the document, this conclusion will be stated more simply as “there would be no effect” or “these species 

would not be affected”.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 746 of 946

Table F-6. Summary of Models or Methods Used to Estimate Exposure of Each Taxon to 

Dicamba

Wildlife Category

Model or Method to Determine 

Estimated Environmental Concentration (EEC)

Birds T-REX version 1.5.2a

Wild Mammals T-REX version 1.5.2 a

Amphibians and Reptiles – Aquatic Assessed as for aquatic animals 

Amphibians and Reptiles – Terrestrial Assessed as for birds 

T-HERPS version 1.1 as a refinement

Terrestrial Invertebrates T-REX version 1.5.2 a

(arthropod residues)

Aquatic Animals Tier I: GENEEC2 

Drift from ground applications was estimated to be 1%

Aquatic Plants (algae, duckweed) Tier I: GENEEC2, 

Drift from ground applications was estimated to be 1% 

Terrestrial and Semi-Aquatic Plants Tier I: TerrPlant; Higher Tier: (semi-aquatic plants) Water monitoring 

analysis

a

T-REX Version 1.5.2 was used to calculate DGT cotton RQ values. Version 1.5.1 was used to calculate DT soybean 

RQ values. Most current T-REX versions were used at the time of preparation. For a given diet type/body weight 

combination, the RQ values obtained were the same for both versions of T-REX.

F.2.6. Literature Review

The toxicity endpoints discussed herein were typically obtained from EPA’s Environmental Fate and 

Ecological Risk Assessment for dicamba (U.S. EPA 2005) and were comprised primarily of 

registrant-submitted data; however, published literature sources were also considered. Consistent 

with EPA’s Overview Document (U.S. EPA 2004), an open literature review was conducted to 

identify publically available literature that could be used in screening level risk assessments. Studies 

were evaluated that provide data, supplemental to registrant-submitted data, which included 

information on additional taxa, toxicity endpoints, routes of exposure or test materials.

The literature review was conducted in two steps. The first step included an evaluation of endpoints 

included in the U.S. EPA ECOTOX (ECOTOXicology) database.135 The most recent publication 

relevant for this analysis included in the ECOTOX database was published in 2006. The second 

step was to conduct a literature search for more recent studies published between 2005 and 2013. 

The open literature search was conducted using ISI Web of Knowledge and Chemical Abstracts 

Service. In total, a search using the criteria “dicamba or 1918-00-9” yielded 1,023 unique results. 

Of these results, 27 were identified as being potentially relevant for use in ecological risk assessment. 

 

135 U.S. EPA ECOTOX Database (v 4.0); URL: http://cfpub.epa.gov/ecotox/
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A further review of the abstracts from these 27 results identified 9 journal articles that warranted 

further review. Each of these articles was obtained and reviewed in detail. Of these, 4 articles 

presented relevant ecotoxicological endpoints that were not previously considered in U.S. EPA risk 

assessments for dicamba.

Three of the four studies that were identified as relevant to ecological risk assessment presented 

terrestrial plant toxicity endpoints; however, all endpoints were greater than the registrant-submitted 

vegetative vigor endpoints used in this assessment (i.e. showed less phytotoxicity) and were 

therefore not considered in the quantitative portion of this assessment. The three relevant studies 

are discussed in more detail below.

 Olszyk et al. (2009) conducted greenhouse studies with pea (Pisum sativum) in 2004. Dicamba 

test rates were 0, 0.0005, 0.001, 0.005, and 0.05 lb a.e./A. Plant height, leaf injury and seed 

yield were study endpoints. Dicamba caused characteristic auxin leaf malformation at 0.05 

lb/A dicamba but effects were absent at lower rates. Dicamba affected seed formation but 

had no effect on overall stem height or biomass production. Across all treatments no effect 

on seed weight (yield) was observed at 0.005 lb/A, and a 25% reduction seed weight (yield) 

at 0.035 lb/A dicamba. Both endpoints are higher than the endpoints presented in 

registrant-submitted studies.

 Greenhouse studies were conducted with potato (Solanum tuberosum) in 2004–2005 (Olszyk et 

al. 2010). Dicamba test rates were 0, 0.0005, 0.001, 0.005, and 0.05 lb a.e./A. Plants were 

harvested at two time points: 28 DAT and 42 DAT on average. Plant height, shoot dry 

weight, injury and tuber weight were measured. Fresh tuber weight was unaffected at the 

0.005 lb/A dicamba treatment level, but significantly reduced at 0.05 lb a.e./A allowing the 

calculation of an EC25 of 0.035 lb/A Shoot dry weight was the most sensitive endpoint with 

no effects on shoot dry weight at rates up to 0.001 lb/A. NOEC and EC25 values for plant 

height and tuber weight occurred at similar treatment rates. All endpoints are higher than 

endpoints presented in registrant-submitted studies.

 A study was conducted in 2008 to evaluate peanuts response to postemergence applications 

of dicamba (Prostko et al. 2011). Dicamba test rates were 0, 0.036, 0.063, 0.125, 0.250, 0.500 

lb a.e./A. Applications were made at 30, 60, and 90 days after peanut planting. Significant 

peanut yield losses were observed at rates as low as 0.036 lb a.e./A and losses at this rate 

range from 2–29% yield reduction relative to controls. The endpoint for yield reduction is 

higher than endpoints presented in registrant-submitted studies.

 A study conducted by Bohnenblust et al. (2013) evaluated direct and indirect effects of 

dicamba on two Lepidopteran species and is potentially relevant for use in ecological risk 

assessment. The results from this study indicate that dicamba is not directly toxic to 

Lepidopteran species at rates up to 0.5 lb a.e./A, the highest rate tested. Since there was no 

direct toxicity observed at the highest rate tested, the study was not utilized in the evaluation 

of potential direct effects. Although indirect effects on one of the species were reported at 

0.05 lb a.e./A, which is equivalent to 10% spray drift of a 0.5 lb a.e./A application or 5% of 

a 1.0 lb a.e./A application, these effects were not observed when the experiment was 

repeated with larger plants. These drift rates are well above the 1% default spray drift rate 

assumed in the screening level assessment (Overview Document, US EPA, 2004); and 

furthermore, with the mandatory label requirements (e.g. nozzle selection, wind speed, 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 748 of 946

ground speed, and boom height) to limit the off-site movement of dicamba even further, 

dicamba exposure off-site will not reach the level at which these indirect effects were 

observed. 

The U.S. EPA ECOTOX database did not include any terrestrial endpoints that were lower (more 

sensitive) than endpoints from registrant-submitted studies. Some aquatic endpoints were available 

in ECOTOX that were lower than endpoints available from registrant-submitted studies; however, 

the associated studies did not meet quality standards set forth in U.S. EPA (2011). Specifically, 

those studies that reported lower aquatic endpoints did not appropriately identify the test material136

or were not a primary source of the data137, which invalidates these studies from further analysis as 

specified in U.S. EPA (2011).

Previous risk assessments, including an assessment prepared for the U.S. Forest Service (Durkin and 

Bosch 2004) were also reviewed. Durkin and Bosch (2004) provided a detailed review of relevant 

routes of exposure and toxicity endpoints and did not present any additional information that is 

inconsistent with U.S. EPA (2005) or this assessment.

F.2.7. Estimates of Foliar Residues and Residue Decline

F.2.7.1. Default Residues

Equations from the U.S. EPA Environmental Fate and Effects Division’s T-REX model (U.S. EPA

2012, 2013) were used to generate maximum and mean estimated environmental concentrations 

(EECs) resulting from an application of 1 lb dicamba a.e./A followed at 6-day intervals by two 0.5 

lb a.e./A applications based on the proposed dicamba use pattern for soybean and cotton with the 

DT trait.138 The exposure estimates were calculated in multiple steps or levels of refinement. In the 

first step, the default assumptions for residue values on foliage and insects were used. This step 

utilized residues in food items as reported in the U.S. EPA’s RED assessment for dicamba (U.S. 

EPA 2005). Dicamba concentrations on food items based on data from Hoerger and Kenaga 

(1972), as modified by Fletcher et al. (1994), were estimated using a first-order residue decline 

method assuming the default half-life of 35 days. 

In the absence of product-specific information, the EPA uses the product application rate coupled 

with the information first presented by Hoerger and Kenaga (1972) to estimate chemical residues on 

foliage, and uses modified values for arthropods as reflected in T-REX Versions 1.5.1 and 1.5.2. 

Using this method, historical residue data gathered from available literature sources are used to give 

 

136 General Invalidation Guideline 5 from U.S. EPA (2011) states that “if the study does not provide proper identification of the test 

material in terms of the percentage of active ingredient, trade name, and/or TGAI, the study is invalid.”

137 From Section 2.1, page 12 of U.S. EPA (2011)

138 This use pattern results in higher residues than the use-pattern in which four post-emergence applications are made with a 

minimum interval of at least 7 days, so this is the use pattern evaluated using T-REX and T-HERPS. As noted previously, this 

use pattern is also more conservative than the proposed label-mandated use pattern for cotton with a 7-day interval between preand post-emergence applications and the two post-emergence applications.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 749 of 946

a generic estimate of residues. The residue estimates are divided into residues on short grass; tall 

grass; broadleaf plants; fruits/pods; arthropods; and seeds. When available, product-specific residue 

information may be used in place of the generic values, and this product-specific information can 

also be used to calculate the rate of dissipation of residues for use in chronic exposure assessments 

(U.S. EPA 2004). Also useful in estimating the exposures to animals in the environment are the 

residue values used to establish food tolerances on animal feed, forage, hay, and fodder. Based on 

the Residue Chemistry Guidelines, a minimum number of field sites are needed to propose an 

animal feed tolerance for pasture, forage and hay (Test Guideline OPPTS 860.1500, U.S. EPA 

1995). For grass forage, fodder, and hay, Bermuda grass, bluegrass, and brome grass or fescue from 

a total of at least 12 trials (4 for each variety) is needed from field sites that represent the different 

geographic regions of the US. The feed tolerance established from these trials was 125 ppm for 

dicamba applications at 1 lb a.e./A.

F.2.7.2. Grass Forage Residues

For dicamba, grass (pasture forage) Day 0 residue values are available from 59 different treatments 

using dicamba salt formulations at application rates of 0.5, 1.0, or 2.0 lb a.e./A. These data from 

each site and rate were normalized to residue values assuming a 1 lb a.e./A application rate, in a 

manner similar to the treatment of the residue data used by Hoerger and Kenaga (1972). This 

normalization of the measured residues assumes a priori that a linear relationship holds across the 

application rate range tested. These values were then plotted as a cumulative distribution and the 

maximum measured value (179 ppm a.e./lb applied) was selected as the worst-case value to use in 

the T-REX calculations based on the large compound-specific dataset available. The calculated 

maximum value of 179 ppm was used as the short grass residue value for a 1 lb a.e./A application. 

The residue value for short grass (179 ppm) was used to derive the tall grass value (82.0 ppm) by 

assuming the same ratio of tall grass to short grass residues (110 ppm ÷ 240 ppm). as reported in 

Hoerger and Kenaga (1972). 

The grass residue studies previously cited also had a residue decline component for each site and 

rate. A summary of the foliar half-life times (in days) calculated from these field trials on pasture 

forage is given in Table F-7. The half-life estimate is the time for half of the dicamba residues to be 

lost from the plant tissue; i.e., the number of days needed for the day 0 measured dicamba residues 

to be half of the amount measured on the day of application. The estimated foliar half-life across all 

pasture forage trials was 5.06 days (arithmetic mean) with an upper 90 percentile confidence limit 

(single sided) of 5.63 days. For the wheat forage trials, the half-life was 2.82 days (arithmetic mean) 

with an upper 90th percentile confidence limit (single sided) of 3.00 days. The upper 90th percentile, 

one tailed, confidence interval for pasture grasses was used to calculate a refined EEC, based upon 

EPA guidance (U.S. EPA 2009a).

Table F-7. Summary of Dicamba Residue Half-Life in Pasture Grasses and Wheat

Item

Dicamba Half-Life (days) in Foliage

Number 

of Values

Arithmetic 

Mean Std Dev Max Min

Upper 90% CL 

on the mean

Pasture grasses 

(all salts)

58 5.06 3.36 19.3 1.95 5.63 a

Wheat forage

(all salts)

41 2.82 0.87 4.87 1.35 3.00

a Half-life value used for refined T-REX analysis.
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All EEC estimates derived using refined residue half-life values employed the half-life value for 

pasture grasses (5.63 days) as opposed to using the value from the wheat forage studies, as it was the 

more conservative estimate (i.e. allows for a slower rate of decline) for dicamba residue decline.

F.2.7.3. Broadleaf Plant Forage Residue Refinements

A residue decline study was conducted for DT-soybeans at two application rates (0.5 and 1.0 lb 

a.e./A) at three field locations (in Arkansas, Illinois, and Nebraska; Mueth and Foster 2010). This 

study provides dicamba-specific information on residues and residue decline on a surrogate 

broadleaf plant (soybean). As for the grass forage, Day 0 residue values from all sites and rates were 

normalized to residue values for a 1.0 lb a.e./A application rate. This normalization of the measured 

residues assumes a priori that a linear relationship holds across the application rate range tested. 

From these normalized values, the maximum residue value per pound applied was determined as 

103.9 mg/kg139. This illustrates the conservativeness of the broadleaf plant residues used in the TREX model.

A foliar decline DT50 was also calculated for dicamba-derived residues from this study. The upper 

90th percentile confidence interval on the mean value of the six DT50 values (4.2 days) was shorter 

than the DT50 derived from the grass forage residue decline study, so the latter value (5.63 days) was 

used in refined T-REX calculations.

F.2.7.4. Estimates of Dicamba Residues in Wildlife Food Items 

As noted above, the T-REX model uses residues in wildlife food items based on data from Hoerger 

and Kenaga (1972), as modified by Fletcher et al. (1994), and a default half-life of 35 days. For a 

single application of 1.0 lb/A, the T-REX default residue values are summarized in Table F-8.

Table F-8. T-REX Default Residue Values for Wildlife Food Items 

Food Item

Kenaga Residue Value (ppm) 

(for a 1 lb/A application)

Upper Bound Mean

Short grass 240 85

Tall grass 110 36

Broadleaf plants 135 45

Fruits/pods/seeds 15 7.0

Arthropods 94 65

 

139 For the soybean forage residue study, the Day 0 residue values and DT50 calculations considered residues as the sum of dicamba 

plus the metabolites DCSA, DGSA, and 5-hydroxydicamba.
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The exposure scenario considered in this analysis is referred to as the 6-day interval maximum use 

pattern (6diMUP) for soybean and cotton with the DT trait, which is an application of 1.0 lb a.e./A, 

followed at 6-day intervals with two sequential applications of 0.5 lb a.e./A each. This 6diMUP was 

modeled using T-REX (U.S. EPA 2012). 

In the following situations, the approaches considered in this analysis to define the maximum 

dicamba residues for the 6-day interval maximum use pattern for soybean and cotton with the DT 

trait are summarized below and presented in Table F-9:

(1) Maximum residues estimated using the T-REX default residues and default half-life 

value (35 days). For example, the highest residue on short grass estimated using 

default residue values and a half-life of 35 days was 415.8 ppm, immediately after the 

3rd sequential application (Day 12).

(2) Maximum residues estimated using the T-REX default residues and a compoundspecific half-life value (5.63 days). For example, the highest residue on short grass 

estimated using default residue values and a refined half-life of 5.63 days was 240 

ppm, immediately following the initial application of 1 lb a.e./A (Day 0).

(3) Maximum residues estimated using measured foliar residues for short and tall grasses 

(maximum and mean measured Day 0 compound-specific residues for the upper 

bound and mean residues, respectively) and a compound-specific refined half-life 

value (5.63 days). For example, the highest residue on short grass estimated using 

measured residue values and a half-life of 5.63 days was 179 ppm, immediately 

following the initial application of 1 lb a.e./A (Day 0).

(4) Maximum residues estimated using measured foliar residues for short and tall grasses 

(90th percentile value for the upper bound residues in short and tall grasses) and a 

compound-specific half-life value (5.63 days). For example, the highest residue (90th 

centile value) on short grass estimated using measured residue values and a half-life 

of 5.63 days was 131 ppm, immediately following the initial application of 1 lb a.e./A 

(Day 0).

Table F-9. Dicamba Residue Values for Wildlife Food Items Considered in the Risk 

Quotient Calculations for Birds and Mammal

Food Item

Highest Residue estimated for the 6-day interval maximum-use pattern for soybeans 

and cotton with the DT trait (3 sequential applications with a 6-day interval) 

(ppm a.e.)

Using Kenaga Default Residues & 

T-REX Default Half-Life a

Using Maximum Measured Residues

& Refined Half-Life b,c

Upper Bound Mean Upper Bound Mean

Short grass 415.8 147.3 179 77.9

Tall grass 190.6 62.4 82.0 33.0

Broadleaf plants 233.9 78.0 135 45

Fruits/pods/seed 26.0 12.1 15.0 7.0
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s

Arthropods 162.9 112.6 94 65

a Using the default residue values and the default half-life of 35 days. 

b Using compound-specific refined residue values for short and tall grass, and a compound-specific refined half-life of 5.63 days. 

Note that residues do not build up with sequential applications because of the short half-life. The highest residue occurs 

immediately after the 1.0 lb a.e./A application at Day 0.

c Tall grass upper bound and mean values were calculated using the refined short grass value and the ratio of Kenaga tall grass to 

short grass values for the upper bound and mean values, respectively.

In situation (1), the 6-day application interval is less than the default half-life; approximately 89% of 

the dicamba from a prior application is present when the next application is made. This results in 

the maximum estimated residues occurring immediately after the third application of the 6-day 

interval maximum use pattern for soybean and cotton with the DT trait. For other situations, the 6-

day application interval is longer than the compound-specific refined half-life value (5.63 days). 

Thus, approximately 48% of the dicamba from a prior application is present when the next 

application is made. Use of the compound-specific half-life value results in the maximum estimated 

residues on food items occurring immediately after the first application (the 1-lb application). 

The versions of the T-REX model used for these analyses allow for modeling residues in the various 

diet types following application of a pesticide at differing applications rates and spray intervals; 

however, it is not designed to allow modification of the dietary food item residues. Thus, the 

maximum refined residues for grasses, based on measured dicamba residues, reported in Table F-9 

were considered in the risk quotient calculations by applying a correction factor to the estimated 

environmental concentrations (EEC) values computed using the standard T-REX model for a single 

1-lb/A application.

Correction factors for the conservative 6-day interval maximum use pattern for soybean and cotton 

with the DT trait assuming refined residue values and refined half-life of 5.63 days were derived 

as follows for short grass and tall grass. The following equations indicate how correction factors 

were derived for upper bound residues:

Correction factor 

(refined short grass) = 

179 ppm (max residue in pasture forage for 1 lb/A)

 = 0.746

240 ppm (Kenaga upper bound residue for 1 lb/A)

Correction factor

(refined tall grass) = same correction factor as for short grass = 0.746

The following equations indicate how correction factors were derived for mean residues:

Correction factor 

(refined short grass) = 

77.9 ppm (mean residue in pasture forage for 1 lb/A)

 = 0.916

85 ppm (Kenaga mean residue for 1 lb/A)

Correction factor

(refined tall grass) = same correction factor as for short grass = 0.916
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Example showing correction of EECs to computed EECs for the 6-day interval maximum use pattern for soybean 

and cotton with the DT trait with refined residues and half-life140:

Avian EEC (short grass) for 

Cotton with DT Trait 6diMUP (20-g 

size class)

=

273.3 ppm 

(TREX EEC for 1 lb/A) x 0.746 = 203.9 ppm

Mammalian EEC (short grass) for 

Cotton with DT Trait 6diMUP (15-g 

size class)

=

228.8 ppm 

(TREX EEC for 1 lb/A) x 0.746 = 170.7 ppm

F.2.8. Estimates of Pond Water Concentrations

The dicamba concentration in a pond immediately adjacent to a treated field was estimated using 

GENEEC Version 2.0, a program to calculate estimated environmental concentration (EEC) values 

considering a standard farm pond scenario.

F.2.8.1. DT Soybean

For the use of dicamba on DT soybean, pond water concentrations were estimated for two 

application scenarios: (1) a single application of dicamba at 1.0 lb a.e./A; and (2) two sequential 

applications of 0.5 lb a.e./A separated by 6 days using the relevant environmental fate parameters 

from Table F-3. The GENEEC EEC values are reported in Table F-10. For the single application 

at 1.0 lb a.e/A, the peak water concentration estimated by GENEEC was 44.33 μg a.e./L. The 

maximum 4 day average concentration was 42.3 ppb and the maximum 90 day average was 14.81 μg 

a.e./L. The peak water concentration following two applications at 0.5 lb a.e/A was 33.35 μg a.e./L. 

The maximum 4 day average concentration was 31.82 μg a.e./L and the maximum 90 day average 

was 11.14 μg a.e./L.

Table F-10. Summary of Dicamba Concentrations in Pond Water Estimated by GENEEC 

Estimate

GENEEC EEC (μg a.e./L)

1.0 lb/A 0.5 + 0.5 lb/A

Peak 44.33 33.35

4-day avg (max) 42.30 31.82

21-day avg (max) 32.84 24.71

60-day avg (max) 20.08 15.10

90-day avg (max) 14.81 11.14

 

140 Values in example may differ slightly from tables due to rounding.
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The combined PRZM and EXAMS programs were used as a higher tier approach to estimate 

exposure concentrations in pond water. In the ecological exposure assessment, PRZM/EXAMS 

simulates a 10 hectare (ha) field immediately adjacent to a 1 ha pond, 2 meters deep with no outlet. 

PRZM/EXAMS were used to simulate the same application scenarios as GENEEC as well as to 

simulate three sequential applications at the maximum use pattern. GENEEC is unable to analyze 

application rates of differing amounts. In practice, PE5 was used as an interface to run the 

combined PRZM/EXAMS programs with varying dates of dicamba application and application 

rates. The PE5 program takes the user inputs, runs PRZM and hands off the edge of field values to 

EXAMS which then estimates the pond water concentrations. Using the multi-run feature within 

PE5, individual dicamba applications were allowed with the first application between March 1 and 

June 15. These dates were chosen to represent a very broad estimate of the time span when 

soybeans would be planted and potentially treated with dicamba in soybean production areas in the 

southern U.S. The soybean application scenario used was the standard EPA Mississippi soybean 

scenario (MSsoybeanSTD.txt) and the Memphis weather data. Combined, this scenario is widely 

recognized as providing a very conservative estimate of runoff from treated fields. The three sets of 

analyses were conducted assuming either a single application rate of 1 lb a.e./A; two applications of 

0.5 lb a.e./A separated by 6 days; or three sequential applications of 1.0 + 0.5 + 0.5 lb a.e./A each 

separated by 6 days.

A comparison of the results from the GENEEC and PRZM/EXAMS modeling is provided in 

Table F-11:

Table F-11. Dicamba Concentrations in Pond Water Estimated by GENEEC and 

PRZM/EXAMS

Applicationsa

Estimated Water Concentration (μg a.e./L)

GENEEC PRZM/EXAMS b

Peak (max) 4 Day (max) Peak 4 Day

1.0 44.33 42.30 32.35 30.45

0.5 + 0.5 33.35 40.02 21.22 19.92

1.0 + 0.5 + 0.5 --

c

--

c 41.64 38.22

a Individual or sequential applications in lb a.e./A; 6-day application intervals.

b 1-in-10-year values.

c The GENEEC model was only used for use patterns with a single rate because it does not have the capability to model multiple 

applications at different rates. 

F.2.8.2. DGT Cotton

For the use of dicamba on DGT cotton, pond water concentrations were estimated for two 

application scenarios: (1) a single application of dicamba at 1.0 lb a.e./A; and (2) four sequential 

applications of 0.5 lb a.e./A separated by 6 days using the relevant environmental fate parameters 

from Table F-3. The GENEEC EEC values are reported in Table F-12. For the single application 

at 1.0 lb a.e/A, the peak water concentration estimated by GENEEC was 44.33 μg a.e./L. The 

maximum 4 day average concentration was 42.3 μg a.e./L and the maximum 90 day average was 

14.81 μg a.e./L. The peak water concentration following four applications at 0.5 lb a.e/A was 41.93 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 755 of 946

μg a.e./L. The maximum 4 day average concentration was 40.02 μg a.e./L and the maximum 90 day 

average was 14.01 μg a.e./L.

Table F-12. Summary of Dicamba Concentrations in Pond Water Estimated by GENEEC 

Estimate

GENEEC EEC (μg a.e./L)

1.0 lb/A 0.5 + 0.5 + 0.5 + 0.5 lb/A

Peak 44.33 41.93

4-day avg (max) 42.30 40.02

21-day avg (max) 32.84 31.08

60-day avg (max) 20.08 19.00

90-day avg (max) 14.81 14.01

GENEEC 2.0 does not have the capability to model multiple applications at different rates. The 

combined PRZM and EXAMS programs were used as a higher tier approach to estimate exposure 

concentrations in pond water assuming a 6-day interval maximum use pattern for dicamba 

(application of 1 lb dicamba a.e./A preemergence followed by two applications of 0.5 lb a.e./A 

postemergence). In the ecological exposure assessment, PRZM/EXAMS simulates a 10 hectare (ha) 

field immediately adjacent to a 1 ha pond, 2 meters deep with no outlet. In practice, PE5 was used 

as an interface to run the combined PRZM/EXAMS programs with varying dates of dicamba 

application and application rates. The PE5 program takes the user inputs, runs PRZM and hands 

off the edge of field values to EXAMS which then estimates the pond water concentrations. Using 

the multi-run feature within PE5, the date of the preemergence application was varied to be any date 

within two weeks prior to the cotton emergence date designated in the selected EPA scenario. The 

second application was fixed to be 5 days after emergence, and the third application date was set to 

be 6 days after the second application. The cotton application scenarios used were the two 

southeastern U.S. standard EPA cotton scenarios--Mississippi (MScottonSTD.txt) and North 

Carolina (NCcottonSTD). These scenarios are widely recognized as providing very conservative 

estimates of runoff from treated fields. 

The results from the GENEEC and PRZM/EXAMS modeling is provided in Table F-13. 

Table F-13. Dicamba Concentrations in Pond Water Estimated by GENEEC and 

PRZM/EXAMS

Applications a

Estimated Water Concentration (μg a.e./L)

GENEEC PRZM/EXAMS b

Peak (max) 4 Day (max) Peak 4 Day

1.0 44.33 42.30 --

c

--

c

0.5 + 0.5+ 0.5+ 0.5 41.93 40.02 --

c

--

c

1.0 + 0.5 + 0.5 --

c

--

c 41.64 38.22

a Individual or sequential applications in lb a.e./A; 6-day application intervals for GENEEC and as described above for 

PRZM/EXAMS.

b 1-in-10-year value based on the highest peak value from the two Southeastern U.S. scenarios (in this case the North Carolina 

scenario with an application date of May 28).
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c The indicated water model was not utilized to determine water concentrations for the defined use pattern on DGT cotton. The

GENEEC model was only used for use patterns with a single rate. PRZM/EXAMS was run for a use pattern with more than 

one use rate.

F.3. Assessment of Non-Target Species

The following sections assess impacts from dicamba on non-target species. The analysis addresses 

avian species, wild mammals, terrestrial invertebrates, aquatic animals, aquatic plants, and terrestrial 

and semi-aquatic plants.

F.3.1. Avian Analysis

F.3.1.1. Avian Toxicity Summary

Table F-14 summarizes the avian toxicity endpoints for dicamba used in this analysis. Where 

available, endpoints with dicamba DGA salt were selected over those for dicamba acid.

Table F-14. EPA Levels of Concern and Toxicity Endpoints for Birds Used in the Analysis

Organism Acute/Chronic LOC Criteria Dicamba 

Endpoint

Units

Birds acute non-listed 0.5 EEC/ LD50 262 a mg a.e./kg bw

acute listed 0.1 EEC/LD50 262 a mg a.e./kg bw

chronic all 1 EEC/NOAEC 695 b mg a.e./kg diet

a Dicamba DGA salt, Bobwhite quail oral LD50 study

b Dicamba acid, reproduction study, Mallard duck.

For acute toxicity endpoint values, the T-REX model uses the LD50 value from the surrogate species 

(in this case Bobwhite quail) and the Mineau factor, and calculates adjusted LD50 values based on 

avian body weight. These adjusted values are presented in Table F-15 and are used in the T-REX 

model to calculate risk quotient values.

Table F-15. Adjusted LD50 values based on body weight

Avian Body

Weight (g)

Adjusted LD50

(mg/kg-bw)

20 188.75

100 240.29

1000 339.42

Table F-16 summarizes the avian acute oral toxicity data for dicamba as reported in the dicamba 

EFED assessment (U.S. EPA 2005) and also includes data from one recent study. Table F-17 
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summarizes the avian subacute dietary study141 endpoints, and Table F-18 summarizes the avian 

reproduction study endpoints as reported in the dicamba EFED assessment.

Dicamba acid is categorized as moderately toxic to avian species with a 14-day oral LD50 for 

bobwhite quail of 188 mg a.e./kg (NOEL = 13.6 mg a.e./kg bw) (U.S. EPA 2005). However, since 

the product being considered for use on DGT cotton and DT soybean is the diglycolamine salt of 

dicamba, the LD50 for that salt (262 mg a.e./kg bw) was used for the risk quotient calculations.

Table F-16. Avian Acute Oral Toxicity for Dicamba Acid and Dicamba Salts

Species % ai LD50

(mg a.i./kg bw)

LD50

(mg a.e./kg bw) Toxicity Category

Dicamba acid

Northern bobwhite quail

(Colinus virginianus) 86.9 188 188 Moderately toxic

Mallard duck

(Anas platyrhynchos) 86.9 1373 1373 Slightly toxic

Zebra fincha

(Taeniopygia guttata)

93.9 213 213 Moderately toxic

Dimethylamine salt

Mallard duck

(Anas platyrhynchos) 48.2 >2510 >2452 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 11.5 >2510 >2452 Practically non-toxic

Potassium salt

Northern bobwhite quail

(Colinus virginianus) 38 724 618 Moderately toxic

Diglycolamine salt

Northern bobwhite quail

(Colinus virginianus) 40 387 262 Moderately toxic

a Results of a recent study; others as cited in U.S. EPA (2005).

 

141 The EPA Overview Document (U.S. EPA, 2004) also refers to this study as an acute dietary study and identifies this study as a part 

of the acute avian assessment.
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Table F-17. Avian Subacute Dietary Studies for Dicamba Acid and Dicamba Salts

Species % ai

LC50

(mg a.i./kgfeed) (ppm)

LC50

(mg a.e./kgfeed) (ppm)

EPA

Toxicity Category

Dicamba acid

Northern bobwhite quail

(Colinus virginianus) 86.6 >10,000 >10,000 Practically non-toxic

Northern bobwhite quail

(Colinus virginianus) 10 >10,000 >10,000 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 86.6 >10,000 >10,000 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 86.6 2009 2009 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 10 >10,000 >10,000 Practically non-toxic

Dimethylamine salt of dicamba

Northern bobwhite quail

(Colinus virginianus) 48.2 >4640 >4533 Practically non-toxic

Northern bobwhite quail

(Colinus virginianus) 11.5 >5620 >5490 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 48.2 >4640 >4533 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 11.5 >5620 >5490 Practically non-toxic

Sodium salt of dicamba

Northern bobwhite quail

(Colinus virginianus) 26.5 >10,000 >9090 Practically non-toxic

Northern bobwhite quail

(Colinus virginianus) 22 >10,000 >9090 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 22 >10,000 >9090 Practically non-toxic

Potassium salt of dicamba

Northern bobwhite quail

(Colinus virginianus) 38 >5620 >4794 Practically non-toxic

Mallard duck

(Anas platyrhynchos) 38 >5620 >4794 Practically non-toxic

Diglycolamine salt of dicamba

Northern bobwhite quail

(Colinus virginianus) 40 >2248 >1522 No more than slightly toxic

Mallard duck

(Anas platyrhynchos) 40 >2248 >1522 No more than slightly toxic

As cited in U.S. EPA (2005).
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Table F-18. Avian Reproduction Toxicity Endpoints for Dicamba Acid

Species

Dicamba 

acid purity 

(%)

NOEC/LOEC 

(mg tech/kg 

feed)

NOEC/LOEC 

(mg a.e./kg feed) 

a

LOEC Endpoints

Northern bobwhite quail

(Colinus virginianus) 86.9 1600/-- 1390/--

No treatment-related 

toxicity

Mallard duck 

(Anas platyrhynchos) 86.9 800/1600 695/1390 Reduction in hatchability

a Corrected for percent purity of the test material (technical grade dicamba in the acid form). 

As cited in U.S. EPA (2005).

F.3.1.2. Avian Exposure Estimates

Dicamba concentrations on food items based on data from Hoerger and Kenaga (1972), as modified 

by Fletcher et al. (1994), were calculated in the manner described above.

The estimated environmental concentrations (EECs) derived assuming a 6-day interval maximum 

use pattern for cotton with the DT trait using the default residue values and a half life of 35 days, are 

provided in Table F-19. The refined dose-based and dietary-based EECs for birds are provided in 

Table F-20, Table F-21, and Table F-22.
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Table F-19. Avian: Estimated Environmental Concentrations Using Kenaga Residues and 

Foliar Half-Life of 35 Days (assuming a 6-day interval maximum use pattern for DGT 

cotton or DT soybean)

Dose-based EECs (mg/kg bw)

Diet Upper Bound Mean

20 g 100 g 1000 g 20 g 100 g 1000 g

Short grass 473.5 270.0 120.9 167.7 95.6 42.8

Tall grass 217.0 123.8 55.4 71.0 40.5 18.1

Broadleaf plants 266.4 151.9 68.0 88.8 50.6 22.7

Fruits/pods 29.6 16.9 7.6 13.8 7.9 3.5

Arthropods 185.5 105.8 47.4 128.2 73.1 32.7

Seeds 6.6 3.8 1.7 3.1 1.8 0.78

Dietary-based EECs (mg/kg feed)

Diet Upper Bound Mean

Subacute Chronic Subacute Chronic

Short grass 415.8 415.8 147.3 147.3

Tall grass 190.6 190.6 62.4 62.4

Broadleaf plants 233.9 233.9 78.0 78.0

Fruits/pods/seeds 26.0 26.0 12.1 12.1

Arthropods 162.9 162.9 112.6 112.6
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Table F-20. Avian: Estimated Environmental Concentrations Using Kenaga Residues and 

Refined Foliar Half-Life of 5.63 Days (assuming a 6-day interval maximum-use pattern for 

DGT cotton or DT soybean)

Diet

Dose-based EECs (mg/kg bw)

Upper Bound Mean 

20 g 100 g 1000 g 20 g 100 g 1000 g

Short grass a 273.3 155.9 69.8 96.8 55.2 24.7

Tall grass a 125.3 71.4 32.0 41.0 23.4 10.5

Broadleaf plants 153.8 87.7 39.3 51.2 29.2 13.1

Fruits/pods 17.1 9.7 4.4 8.0 4.6 2.0

Arthropods 107.1 61.0 27.3 74.0 42.2 18.9

Seeds 3.8 2.2 1.0 1.8 1.0 0.45

Diet

Dietary-based EECs (mg/kg feed)

Upper Bound Mean

Subacute Chronic Subacute Chronic

Short grass a 240.0 240.0 85.0 85.0

Tall grass a 110.0 110.0 36.0 36.0

Broadleaf plants 135.0 135.0 45.0 45.0

Fruits/pods/seeds 15.0 15.0 7.0 7.0

Arthropods 94.0 94.0 65.0 65.0

a Residues refined as described in Section F.2.7.4.
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Table F-21. Avian: Estimated Environmental Concentrations Using Maximum Measured 

Residue Estimates (short and tall grass) and Refined Foliar Half-Life of 5.63 Days 

(assuming a 6-day interval maximum use pattern for DGT cotton or DT soybean)

Diet

Dose-based EECs (mg/kg bw)

Upper Bound Mean

20 g 100 g 1000 g 20 g 100 g 1000 g

Short grass a 203.9 116.3 52.0 88.7 50.6 22.7

Tall grass a 93.4 53.3 23.8 37.6 21.4 9.6

Broadleaf plants 153.8 87.7 39.3 51.3 29.2 13.1

Fruits/pods 17.1 9.7 4.4 8.0 4.5 2.0

Arthropods 107.1 61.0 27.3 74.0 42.2 18.9

Seeds 3.8 2.2 0.97 1.8 1.0 0.45

Diet

Dietary-based EECs (mg/kg feed)

Upper Bound Mean

Subacute Chronic Subacute Chronic

Short grass a 179.0 179.0 77.9 77.9

Tall grass a 82.0 82.0 33.0 33.0

Broadleaf plants 135.0 135.0 45.0 45.0

Fruits/pods/seeds 15.0 15.0 7.0 7.0

Arthropods 94.0 94.0 65.0 65.0

a Residues refined as described in Section F.2.7.4.
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Table F-22. Avian: Estimated Environmental Concentrations Using Refined Maximum 

Measured Residue Estimates (90th centile value for short and tall grass) and Refined Foliar 

Half-Life of 5.63 Days (assuming a 6-day interval maximum use pattern for DGT cotton or 

DT soybean)

Diet

Dose-based EECs (mg/kg bw)

Upper Bound Mean 

20 g 100 g 1000 g 20 g 100 g 1000 g

Short grass a 149.2 85.1 38.1 88.7 50.6 22.7

Tall grass a 68.4 39.0 17.5 37.6 21.4 9.6

Broadleaf plants 153.8 87.7 39.3 51.3 29.2 13.1

Fruits/pods 17.1 9.7 4.4 8.0 4.5 2.0

Arthropods 107.1 61.0 27.3 74.0 42.2 18.9

Seeds 3.8 2.2 0.97 1.8 1.0 0.45

Diet

Dietary-based EECs (mg/kg feed)

Upper Bound Mean

Subacute Chronic Subacute Chronic

Short grass a 131.0 131.0 77.9 77.9

Tall grass a 60.0 60.0 33.0 33.0

Broadleaf plants 135 135 45 45

Fruits/pods/seeds 15.0 15.0 7.0 7.0

Arthropods 94 94 65 65

a Residues refined as described in Section F.2.7.4.

F.3.1.3. Avian Risk Quotient Calculations

As an initial screening-level analysis, the estimated exposure concentrations from the T-REX model 

along with the appropriate toxicity endpoints (Table F-14), adjusted to avian body weight by T-REX 

as indicated in Table F-15 were used to calculate chronic and acute risk quotients using default 

Kenaga residue and half-life values (see Table F-23). The EECs used to derive these risk quotients 

are summarized in Table F-19.

In addition to the default exposure values, refined exposure estimates were developed utilizing 

default Kenaga residue values and the dicamba-specific refined foliar half-life of 5.63 days, and also 

utilizing maximum measured dicamba residues on grasses and the dicamba-specific refined foliar 

half-life value of 5.63 days. Risk quotients considering default Kenaga residue values and the refined 

foliar half-life value were calculated using the EECs summarized in Table F-20. The refined risk 

quotients are provided in Table F-24. Risk quotients considering the refined residues in short and 

tall grasses, and a foliar half-life of 5.63 days were also calculated using the residues summarized in 

Table F-21. The refined risk quotients are provided in Table F-25. All risk quotients presented in 

Table F-23 – Table F-25 assume a 6-day interval maximum use pattern for DGT cotton or DT 

soybean.
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Table F-23. Avian: Risk Quotients Using Kenaga Residues and Foliar Half-Life of 35 Days 

(assuming a 6-day interval maximum use pattern for DGT cotton or DT soybean)

Diet

Acute RQs: (Dose-based EEC/adjusted LD50)

Upper Bound Residues

20 g 100 g 1000 g

Short grass 2.51 1.12 0.36

Tall grass 1.15 0.52 0.16

Broadleaf plants 1.41 0.63 0.20

Fruits/pods 0.16 0.07 0.02

Arthropods 0.98 0.44 0.14

Seeds 0.03 0.02 < 0.01

Diet

Dietary-based RQs: (Dietary-based EEC/LC50 or NOAEC)

Upper Bound Residues Mean Residues

Subacute Chronic Subacute Chronic

Short grass <0.28 0.60 <0.10 0.21

Tall grass <0.13 0.27 <0.04 0.09

Broadleaf plants <0.16 0.34 <0.05 0.11

Fruits/pods/seeds <0.02 0.04 <0.01 0.02

Arthropods <0.11 0.23 <0.07 0.16

Values in bold font indicate where the risk quotient exceeds the level of concern (0.5 for acute; 1.0 for chronic).
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Table F-24. Avian: Risk Quotients Using Kenaga Residues and Refined Foliar Half-Life of 

5.63 Days (assuming a 6-day interval maximum-use pattern for DGT cotton or DT soybean)

Diet

Acute RQs: (Dose-based EEC/adjusted LD50)

Upper Bound Residues

20 g 100 g 1000 g

Short grass a 1.45 0.65 0.21

Tall grass a 0.66 0.30 0.09

Broadleaf plants 0.81 0.36 0.12

Fruits/pods 0.09 0.04 0.01

Arthropods 0.57 0.25 0.08

Seeds 0.02 0.01 <0.01

Diet

Dietary-based RQs (Dietary-based EEC/LC50 or NOAEC)

Upper Bound Residues Mean Residues

Subacute Chronic Subacute Chronic

Short grass a <0.16 0.35 <0.06 0.12

Tall grass a <0.08 0.16 <0.02 0.05

Broadleaf plants <0.09 0.19 <0.03 0.06

Fruits/pods/seeds <0.01 0.02 <0.01 0.01

Arthropods <0.07 0.14 <0.04 0.09

Values in bold font indicate where the risk quotient exceeds the level of concern (0.5 for acute; 1.0 for chronic).

a Residues refined as described in Section F.2.7.4.
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Table F-25. Avian: Risk Quotients Using Maximum Measured Residues for Vegetation 

(short and tall grass) and Refined Foliar Half-Life of 5.63 Days (assuming a 6-day interval

maximum use pattern for DGT cotton or DT soybean)

Diet

Acute RQs: (Dose-based EEC/adjusted LD50)

Upper Bound Residues

20 g 100 g 1000 g

Short grass a 1.08 0.48 0.15

Tall grass a 0.49 0.22 0.07

Broadleaf plants 0.81 0.36 0.12

Fruits/pods 0.09 0.04 0.01

Arthropods 0.57 0.25 0.08

Seeds 0.02 0.01 <0.01

Diet

Dietary-based RQs (Dietary-based EEC/LC50 or NOAEC)

Upper Bound Residues Mean Residues

Subacute Chronic Subacute Chronic

Short grass a <0.12 0.26 <0.06 0.11

Tall grass a <0.06 0.12 <0.03 0.05

Broadleaf plants <0.09 0.19 <0.03 0.07

Fruits/pods/seeds <0.01 0.02 <0.01 0.01

Arthropods <0.07 0.14 <0.05 0.09

Values in bold font indicate where the risk quotient exceeds the level of concern (0.1 for acute; 1.0 for chronic).

a Residues refined as described in Section F.2.7.4.

F.3.1.4. Avian Discussion and Conclusions

The risk quotients shown in Section F.3.1.3 above, even those calculated with refined residues, are 

based on very conservative assumptions which likely overestimate the potential for adverse effects. 

These assumptions are:

 The organism consumes 100% of its diet from a dicamba-treated area.

 For RQs calculated with upper bound EECs, 100% of the organism’s diet, 100% of the 

time, contains residues at the upper bound.

 The organism consumes 100% of its diet as one food type (e.g. short grass, tall grass, 

broadleaf forage, arthropods, or fruits, seeds and pods) which for certain food types (e.g. 

short grass) may have very high EECs.

This potential for overestimation should be taken into consideration as results are considered.
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Importantly, LOCs are not exceeded even using default residue assumptions when the most relevant 

route of exposure—dietary-based—is considered. Although EPA’s default approach to assessing 

acute risk is based on a single oral gavage dose (i.e., the entire dose is delivered to the animal at one 

time, typically after being dissolved in corn oil), in reality, any pesticide exposure will not occur in 

this manner – but rather through dietary consumption of dicamba-exposed prey or food items. As a 

result, the gavage route of administration overestimates the exposure expected to occur in nature, 

and methods resulting in a dose-delivery over time (e.g., dietary exposure) are more environmentally 

relevant. Therefore, the use of the acute oral toxicity test (i.e., oral gavage) to predict risk of 

dicamba to birds in this case should be considered to be a screening-level approach that is expected 

to overestimate actual risk.

Even with gavage dosing, the LOC is exceeded only for the smallest birds consuming 100% short 

grass, broadleaf plants, or arthropods at the maximum residue value. Given the layers of 

conservative assumptions incorporated within that assessment (including that birds this size are not 

strictly herbivores) and the only slight exceedances of the LOC, it is reasonable to conclude that 

dicamba use on DT soybean or DGT cotton will not harm avian species. A similar conclusion can 

be reached for terrestrial-phase amphibians and reptiles, for which avian species are a surrogate.

F.3.2. Wild Mammal Analysis

F.3.2.1. Wild Mammal Toxicity Summary

Table F-26 summarizes the mammalian toxicity endpoints for dicamba used in this analysis.

Table F-26. Mammals: EPA Levels of Concern and Toxicity Endpoints Used in the 

Analysis

Organism Acute/Chronic LOC Criteria Dicamba 

Endpoint

Units

Mammals Acute non-listed 0.5 EEC/LD50 2,740 a mg a.e./kg-bw

Acute listed 0.1 EEC/LD50 2,740 a mg a.e./kg bw

chronic all 1 EEC/NOAEC 500 b mg a.e./kg diet

chronic all 1 EEC/NOAEL 45 b mg a.e./kg bw

a Dicamba acid, rat oral LD50 study. As cited in U.S. EPA (2005).

b Dicamba acid, rat reproduction study. As cited in U.S. EPA (2005).

The acute and chronic toxicity values adjusted for body weight as calculated by T-REX are shown 

TableF-27. These values are used by T-REX to calculate risk quotient values.
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Table F-27. Adjusted toxicity values based on body weight

Mammalian

Class

Body

Weight

Adjusted LD50

(mg/kg bw)

Adjusted

NOAEL

Herbivores/

insectivores

15 6022.06 98.90

35 4872.49 80.02

1000 2107.50 34.61

Granivores

15 6022.06 98.90

35 4872.49 80.02

1000 2107.50 34.61

Table F-28 provides a summary of the acute toxicity endpoints and Table F-29 summarizes the 

mammalian sub-chronic and reproductive toxicity values for dicamba. Dicamba acid is classified as 

“practically nontoxic” to laboratory mammals in acute oral toxicity studies.

Table F-28. Mammalian Acute Toxicity for Dicamba Acid

Species

% 

Purity Test Type

Toxicity Value

(mg a.e./kg -bw) a

Affected 

Endpoints

Rat (Rattus norvegicus) Tech Acute oral LD50 = 2,740 Mortality

a Study: MRID 00078444, as cited in U.S. EPA (2005).

Table F-29. Mammalian Subchronic and Developmental/Reproductive Toxicity for 

Dicamba Acid

Species Purity Test Type Endpoint

Toxicity Value

(mg a.e./kgbw/day)

Affected 

Endpoints

Rat

(Charles River CD) 86.8 %

Subchronic 

feeding 13 

weeks

NOAEL / 

LOAEL 500 / 1000

body weight 

changes; liver 

effects

Rat

(Charles River CD) 85.8 % Developmental NOAEL / LOAEL

160 / 400

>400/--

Maternal tox a

Developmental

Rabbit

(New Zealand White) 90.5 % Developmental NOAEL / LOAEL

62.5 / 150

150 / 300

Maternal tox b

Developmental c

Rat

(Sprague-Dawley) 86.5 % Reproduction NOAEL / LOAEL

122 / 419 (males)

136 / 450 (females)

45 / 136 d

Systemic tox

Offspring tox 

Reproductive

a Maternal toxicity – Mortality, clinical signs of neurotoxicity, decreased body weight gain and food consumption

Developmental toxicity - No treatment related fetal gross, skeletal, or visceral anomalies

b Maternal toxicity – Abortion, clinical signs of toxicity (ataxia, rales, decreased motor activity), decreased body weight gain and food 

consumption
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c Developmental toxicity – Irregular ossification of internasal bones

d These dose-based values are equivalent to 500 and 1500 mg/kg diet, respectively.

Source: U.S. EPA (2005).

F.3.2.2. Wild Mammal Exposure Estimates

Dicamba concentrations on food items based on data from Hoerger and Kenaga (1972), as modified 

by Fletcher et al. (1994), were calculated in the manner described above.

The estimated environmental concentrations (EECs) derived for a 6-day interval maximum use 

pattern for DGT cotton or DT soybean using the default residue values and a default half-life of 35 

days, are provided in Table F-30. The refined dose-based and dietary-based EECs for wild 

mammals are provided in Table F-31 through Table F-33.

Table F-30. Mammals: Estimated Environmental Concentrations Using Kenaga Residues 

& Foliar Half-Life of 35 Days (assuming a 6-day interval maximum use pattern for DGT 

cotton or DT soybean)

Diet

Dose-based EECs (acute and chronic) (mg/kg bw)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 1000 g

Short grass 396.4 274.0 63.5 140.4 97.0 22.5

Tall grass 181.7 125.6 29.1 59.5 41.1 9.5

Broadleaf plants 223.0 154.1 35.7 74.3 51.4 11.9

Fruits/pods 24.8 17.1 4.0 11.6 8.0 1.9

Arthropods 155.3 107.3 24.9 107.4 74.2 17.2

Seeds 5.5 3.8 0.88 2.6 1.8 0.4

Diet

Dietary-based EECs (chronic) (mg/kg feed)

Upper Bound Mean

Short grass 415.8 147.3

Tall grass 190.6 62.4

Broadleaf plants 233.9 78.0

Fruits/pods/seeds 26.0 12.1

Arthropods 162.9 112.6
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Table F-31. Mammals: Estimated Environmental Concentrations Using Kenaga Residues 

and Refined Foliar Half-life of 5.63 Days (assuming a 6-day interval maximum-use pattern 

for DGT cotton or DT soybean)

Diet

Dose-based EECs (acute and chronic) (ppm)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 1000 g

Short grass a 228.8 158.2 36.7 81.0 56.0 13.0

Tall grass a 104.9 72.5 16.8 34.3 23.7 5.50

Broadleaf plants 128.7 89.0 20.6 42.9 29.7 6.88

Fruits/pods 14.3 9.88 2.29 6.67 4.61 1.07

Arthropods 89.6 61.9 14.4 62.0 42.8 9.93

Seeds 3.18 2.20 0.51 1.48 1.03 0.24

Diet

Dietary-based EECs (chronic) (ppm)

Upper Bound Mean

Short grass a 240 85

Tall grass a 110 36

Broadleaf plants 135 45

Fruits/pods/seeds 15.0 7.0

Arthropods 94 65

a Residues refined as described in Section F.2.7.4.
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Table F-32. Mammals: Estimated Environmental Concentrations Using Maximum 

Measured Residues (short and tall grass) and Refined Foliar Half-life of 5.63 Days 

(assuming a 6-day interval maximum-use pattern for DGT cotton or DT soybean)

Diet

Dose-based EECs (acute and chronic) (ppm)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 1000 g

Short grass a 170.6 117.9 27.3 74.3 51.3 11.9

Tall grass a 78.2 54.1 12.5 31.5 21.7 5.04

Broadleaf plants 128.7 89.0 20.6 42.9 29.7 6.88

Fruits/pods 14.3 9.88 2.29 6.67 4.61 1.07

Arthropods 89.6 61.9 14.4 62.0 42.8 9.93

Seeds 3.18 2.20 0.51 1.48 1.03 0.24

Diet

Dietary-based EECs (chronic) (ppm)

Upper Bound Mean

Short grass a 179 77.9

Tall grass a 82 33

Broadleaf plants 135 45

Fruits/pods/seeds 15.0 7.0

Arthropods 94 65

a Residues refined as described in Section F.2.7.4.
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Table F-33. Mammals: Estimated Environmental Concentrations Using Refined 

Maximum Measured Residues (90th centile value for short and tall grass) and Refined Foliar 

Half-life of 5.63 Days (assuming a 6-day interval maximum-use pattern for DGT cotton or 

DT soybean)

Diet

Dose-based EECs (acute and chronic) (mg/kg bw)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 1000 g

Short grass a 124.9 86.3 20.0 74.3 51.3 11.9

Tall grass a 57.2 39.6 9.2 31.5 21.7 5.04

Broadleaf plants 128.7 89.0 20.6 42.9 29.7 6.88

Fruits/pods 14.3 9.88 2.29 6.67 4.61 1.07

Arthropods 89.6 61.9 14.4 62.0 42.8 9.93

Seeds 3.18 2.20 0.51 1.48 1.03 0.24

Diet

Dietary-based EECs (chronic) (mg/kg feed)

Upper Bound Mean

Short grass a 131.0 77.9

Tall grass a 60.0 33.0

Broadleaf plants 135 45

Fruits/pods/seeds 15.0 7.0

Arthropods 94.0 65.0

a Residues refined as described in Section F.2.7.4.

F.3.2.3. Wild Mammal Risk Quotient Calculations

The T-REX model and the appropriate toxicity endpoints (Table F-26) modified by T-REX as 

indicated in Table F-27 were used to calculate acute and chronic risk quotients for wild mammals. 

At the screening-level, the default Kenaga residue and default half-life value of 35 days were 

considered (Table F-34). The EECs used to derive these risk quotients are summarized in Table F30.

Refined exposure estimates were developed utilizing default Kenaga residue values and the dicambaspecific refined foliar half-life of 5.63 days, and also utilizing maximum and 90th percentile measured 

dicamba residues on grasses and the dicamba-specific refined foliar half-life value of 5.63 days. 

Chronic risk quotients considering default Kenaga residue values and the refined foliar half-life value 

were calculated using the residues summarized in Table F-31. The refined risk quotients are 

provided in Table F-35. Risk quotients for chronic exposure, considering refined residues in grasses, 

and a refined foliar half-life of 5.63 days, were calculated using the EEC values presented in Table F32 and Table F-33. The refined risk quotients are provided in Table F-36 and Table F-37. All risk 

quotients are for a 6-day interval maximum use pattern for DGT cotton or DT soybean.
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Table F-34. Mammals: Risk Quotients Using Kenaga Residues and Foliar Half-Life of 35 

Days (assuming a 6-day interval maximum use pattern for DGT cotton or DT soybean)

Diet

Acute RQs: (Dose-based EEC/adjusted LD50)

Upper Bound

15 g 35 g 1000 g

Short grass 0.066 0.056 0.030

Tall grass 0.030 0.026 0.014

Broadleaf plants 0.037 0.032 0.017

Fruits/pods 0.004 0.004 0.002

Arthropods 0.026 0.022 0.012

Seeds < 0.001 < 0.001 < 0.001

Diet

Chronic RQs: (Dose-based EEC/adjusted NOAEL)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 1000 g

Short grass 4.01 3.42 1.84 1.42 1.21 0.65

Tall grass 1.84 1.57 0.84 0.60 0.51 0.28

Broadleaf plants 2.25 1.93 1.03 0.75 0.64 0.34

Fruits/pods 0.25 0.21 0.11 0.12 0.10 0.05

Arthropods 1.57 1.34 0.72 1.09 0.93 0.50

Seeds 0.06 0.05 0.03 0.03 0.02 0.01

Diet

Chronic RQs: (Dietary-based EEC/NOAEC)

Upper Bound Mean

Short grass 0.83 0.29

Tall grass 0.38 0.12

Broadleaf plants 0.47 0.16

Fruits/pods/seeds 0.05 0.02

Arthropods 0.33 0.23

Values in bold font indicate where the risk quotient exceeds the level of concern (0.5 for acute; 1.0 for chronic).
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Table F-35. Mammals: Chronic Risk Quotients Using Kenaga Residues and Refined Foliar 

Half-Life of 5.63 Days (assuming a 6-day interval maximum-use pattern for DGT cotton or 

DT soybean)

Diet

Chronic RQs: (Dose-based EEC/adjusted NOAEL)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 10000 g

Short grassa 2.31 1.97 1.06 0.82 0.70 0.38

Tall grassa 1.06 0.91 0.49 0.35 0.30 0.16

Broadleaf plants 1.30 1.11 0.60 0.43 0.37 0.20

Fruits/pods 0.14 0.12 0.07 0.07 0.06 0.03

Arthropods 0.91 0.77 0.41 0.63 0.54 0.29

Seeds 0.032 0.027 0.015 0.015 0.013 0.007

Values in bold font indicate where the risk quotient exceeds the level of concern (1.0 for chronic).

a Residues refined as described in Section F.2.7.4.

Table F-36. Mammals: Chronic Risk Quotients Using Maximum Measured Residues 

(short and tall grass) and Refined Foliar Half-life of 5.63 Days (assuming a 6-day interval

maximum-use pattern for DGT cotton or DT soybean)

Diet

Chronic RQs: (Dose-based EEC/adjusted NOAEL)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 10000 g

Short grass a 1.72 1.47 0.79 0.75 0.64 0.34

Tall grass a 0.79 0.68 0.36 0.32 0.27 0.15

Broadleaf plants 1.30 1.11 0.60 0.43 0.37 0.0

Fruits/pods 0.14 0.12 0.07 0.07 0.06 0.03

Arthropods 0.91 0.77 0.41 0.63 0.54 0.29

Seeds 0.032 0.027 0.015 0.015 0.013 0.007

Values in bold font indicate where the risk quotient exceeds the level of concern (1.0 for chronic).

a Residues refined as described in Section F.2.7.4.
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Table F-37. Mammals: Chronic Risk Quotients Using Refined Maximum Measured 

Residues (90th centile value for short and tall grass) and Refined Foliar Half-life of 5.63 Days 

(assuming a 6-day interval maximum-use pattern for DGT cotton or DT soybean)

Diet

Chronic RQs: (Dose-based EEC/adjusted NOAEL)

Upper Bound Mean

15 g 35 g 1000 g 15 g 35 g 10000 g

Short grass a 1.26 1.08 0.58 0.75 0.64 0.34

Tall grass a 0.57 0.49 0.26 0.32 0.27 0.15

Broadleaf plants 1.30 1.11 0.60 0.43 0.37 0.20

Fruits/pods 0.14 0.12 0.07 0.07 0.06 0.03

Arthropods 0.91 0.77 0.41 0.63 0.54 0.29

Seeds 0.032 0.027 0.015 0.015 0.013 0.007

Values in bold font indicate where the risk quotient exceeds the level of concern (1.0 for chronic).

a Residues refined as described in Section F.2.7.4.

F.3.2.4. Wild Mammal Discussion and Conclusions

The risk quotients shown in Section F.3.2.3 above, even those calculated with refined residues, are 

based on very conservative assumptions which likely overestimate the potential for adverse effects. 

These assumptions are:

 The organism consumes 100% of its diet from a dicamba-treated area

 For RQs calculated with upper bound EECs, 100% of the organism’s diet 100% of the time 

contains residues at the upper bound

 The organism consumes 100% of its diet as one food type (e.g. short grass, tall grass, 

broadleaf forage, arthropods, or fruits, seeds and pods) which for certain food types (e.g. 

short grass) may have very high EECs.

This potential for overestimation should be taken into consideration as results are considered.

For wild mammals, the acute risk quotients are much less than the LOC of 0.5. Therefore, it can be 

concluded that risk from acute exposure to dicamba used on DGT cotton or DT soybean can be 

excluded from concern and, therefore, wild mammals would not be affected by dicamba use on DT 

soybean or DGT cotton.

For chronic risk, the risk quotients derived using Kenaga residue and the default half-life values 

exceed the LOC of 1.0 for several dietary types (Table F-34). 

When upper bound maximum measured residue estimates for grasses and a refined half-life value 

are considered (Table F-32), small and medium-sized wild mammals consuming short grass and 

broadleaf plants have risk quotients that only slightly exceed the LOC. Importantly, however, even 

when assessing risks to threatened and endangered species, EPA specifies that mean residues can be 
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considered for chronic exposures (rather than using maximum residues) (Overview Document, p. 

40). Considering the rapid decline of foliar residues of dicamba, exposure over days or weeks will 

not occur continuously at the maximum Day 0 residue value. Use of the mean Day 0 residue value 

is still a conservative assumption. When mean residues are considered (with the refinements 

mentioned above), none of the chronic risk quotients for wild mammals exceed the LOC, indicating 

that risk of adverse effects from chronic exposure to dicamba used on DGT cotton or DT soybean 

can be excluded from concern and, therefore, wild mammals would not be affected. 

F.3.3. Terrestrial Invertebrate Analysis

F.3.3.1. Honeybee Toxicity Summary

The potential for adverse effects to threatened or endangered terrestrial invertebrate species was 

assessed using the honeybee as a surrogate. Table F-38 summarizes the honeybee toxicity data for 

dicamba acid, as reported in the dicamba European Union and EFED assessments (EFSA 2011; 

U.S. EPA 2005).

Table F-38. Non-Target Invertebrates - Acute Contact Toxicity to Dicamba

Species

Test 

Material

LD50 

(μg a.e./bee) Toxicity Category Source

Honeybee (Apis mellifera) Technical >100 Practically non-toxic EFSA 2011

Technical >90.65 Practically non-toxic U.S. EPA 2005

The toxicity endpoint used to assess the potential for adverse effects to terrestrial invertebrates is 

calculated by converting the acute contact LD50 value of >100 μg a.e./bee to a dose-based estimate 

by assuming an adult honeybee weighs approximately 0.128 g (i.e., 100 μg a.e./bee ÷ 0.128 g = 781 

μg a.e./g bee) (US EPA 2008a).

F.3.3.2. Honeybee Exposure Estimates

The EECs to honey bees were estimated from upper bound residues on arthropods (T-REX v1.5.2) 

assuming a 6-day interval maximum use pattern using refined compound-specific half-life values 

described in Section F.2.7.4.

F.3.3.3. Honeybee Risk Quotient Calculations

The RQ values were estimated by dividing the EECs for arthropods by the dose-based LD50 value 

(μg a.e./g bee). The RQ values are presented in Table F-39.
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Table F-39. Risk Quotients for Non-target Invertebrates (assuming a 6-day interval ve 

maximum use pattern for DGT cotton or DT soybean)

Organism

EEC a (μg a.e./g)

Arthropods

LD50 b

(μg a.e./g)

RQ

Arthropods

Honeybee 

(Apis mellifera) 94 >781 <0.12

a See Table F-9.

b LD50 (μg/g) = LD50 (μg/bee) / 0.128 g

F.3.3.4. Honeybee Discussion and Conclusions

The RQ value for arthropods (<0.12) is less than the LOC (0.5) for terrestrial invertebrates, 

indicating that risk to pollinators from dicamba use on DGT cotton or DT soybean can be excluded 

from concern.

When non-listed terrestrial invertebrates are considered, the RQ value is below the LOC (0.5), 

indicating that there would be no indirect effects on wildlife categories relying on terrestrial 

invertebrates as a food source.

F.3.4. Aquatic Animal Analysis

F.3.4.1. Aquatic Animal Toxicity Summary

Table F-40 summarizes the acute toxicity of dicamba DGA salt to aquatic animals (fish, 

invertebrates, and aquatic- phase amphibians) as cited in the U.S. EPA EFED assessment (U.S. EPA 

2005) as well as more recent chronic tests conducted with dicamba acid. Freshwater fish are used as 

a surrogate for aquatic-phase amphibians (EFED Registration Chapter, U.S. EPA 2005, page 24). 

As shown in Table F-40, dicamba DGA salt and dicamba acid have very little biological activity with 

respect to aquatic animals.
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Table F-40. Toxicity of Dicamba and Dicamba DGA salt to Aquatic Animals

Species % a.i. Exposure 

Duration (d)

LC50 / EC50 / NOEC EPA

(mg a.i./L) (mg a.e./L) Toxicity Category

Acute

Rainbow trout 

(Oncorhynchus mykiss) 40.15 a 4 >400 >270.8 Practically non-toxic

Bluegill sunfish 

(Lepomis macrochirus 40.15 a 4 >400 >270.8 Practically non-toxic

Waterflea

(Daphnia magna)

40.15 a 2 >400 >270.8 Practically non-toxic

Chronic

Fathead minnow ELS 

(Pimephales promelas) 92.9 b 32 ≥10 Practically non-toxic

Sheepshead minnow 

ELS 

(Cyprinodon variegatus)

93.9 b 32 11 Practically non-toxic

Mysid Lifecycle

(Americamysis bahia)

93.9 b 28 5.8 Practically non-toxic

a Studies conducted with the dicamba DGA salt.

b Studies conducted with TGAI.

F.3.4.2. Aquatic Animal Exposure Estimates

Exposure estimates for aquatic animals potentially exposed to dicamba are derived from GENEEC 

and PRZM/EXAMS modeling estimates as reported in Section F.2.8.

F.3.4.3. Aquatic Risk Quotient Calculations

For aquatic animal species, the risk quotients are calculated as follows:

Aquatic Animal RQacute =

Maximum initial EEC (mg a.e./L)

EC50 or LC50 (mg a.e./L)

Aquatic Animal RQchronic =

Maximum initial EEC (mg a.e./L)

NOEC (mg a.e./L)

Table F-41 and Tables F-42 to F-43 summarize the acute and chronic risk quotients for endangered 

aquatic animals determined from the most sensitive endpoints for each taxa listed in Table F-40.
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Table F-41. Tier I Risk Quotients for Aquatic Animals based on GENEEC Exposure 

Estimates for DGT Cotton and DT Soybeans.

Taxonomic Group

Peak Peak Peak

1 lb/A 2 x 0.5 lb/A 4 × 0.5 lb/A

EEC (ppm) RQa EEC (ppm) RQa EEC (ppm) RQa

Acute

Fish 0.0443 <0.0002 0.0334 <0.0002 0.0419 <0.0002

Invertebrate 0.0443 <0.0002 0.0334 <0.0002 0.0419 <0.0002

Amphibian 

(aquatic-phase)b

0.0443 <0.0002 0.0334 <0.0002 0.0419 <0.0002

Chronic

Fish 0.0443 ≤0.0044 0.0334 ≤0.0033 0.0419 ≤0.0042

Invertebrate 0.0443 0.0076 0.0334 0.0058 0.0419 0.0072

Amphibian 

(aquatic-phase) b

0.0443 ≤0.0044 0.0334 ≤0.0033 0.0419 ≤0.0042

a GENEEC is unable to model a 6-day interval maximum use pattern for dicamba use on soybeans or cotton with the DT trait due to 

sequential applications at different application rates.

b Risk quotient calculated based on effects endpoint for fish.

Table F-42. Tier II Risk Quotients for Aquatic Animals based on PRZM/EXAMS 

Exposure Estimates using a 6-day interval maximum use pattern for DGT coton (1.0 lb/A + 

0.5 lb/A + 0.5 lb/A)

Taxonomic Group

Peak (1-in-10 yr) 96 Hour (1-in-10 yr)

EEC (ppm) RQ EEC (ppm) RQ

Acute

Fish 0.0416 <0.0002 0.0382 <0.0002

Invertebrate 0.0416 <0.0002 0.0382 <0.0002

Amphibian (aquatic phase) b 0.0416 <0.0002 0.0382 <0.0002

Chronic

Fish 0.0416 ≤0.0042 0.0382 ≤0.0038

Invertebrate 0.0416 0.0072 0.0382 0.0066

Amphibian (aquatic phase) b 0.0416 ≤0.0042 0.0382 ≤0.0038

bRisk quotient calculated based on effects endpoint for fish.
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Table F-43. Tier II Risk Quotients for Aquatic Animals based on PRZM/EXAMS Exposure 

Estimates using the maximum use pattern for DT soybean (1.0 lb/A + 0.5 lb/A + 0.5 lb/A)

Taxonomic Group

Peak 96 Hour

EEC (ppm) RQ EEC (ppm) RQ

Acute

Fish 0.0327 <0.00013 0.0308 <0.00012

Invertebrate 0.0327 <0.00013 0.0308 <0.00012

Amphibian (aquatic phase) 0.0327 <0.00013 0.0308 <0.00012

Chronic

Fish 0.0327 0.0033 0.0308 0.0031

Invertebrate 0.0327 0.0056 0.0308 0.0053

Amphibian (aquatic phase) 0.0327 0.0033 0.0308 0.0031

F.3.4.4. Aquatic Animal Analysis Summary and Conclusions

The acute and chronic RQ values for endangered and non-endangered aquatic animals exposed to 

dicamba as estimated by GENEEC and PRZM/EXAMS are all less than the LOC values. 

Therefore, it can be concluded that risk from exposure to dicamba following use on DGT cotton or 

DT soybean can be excluded from concern and, therefore, aquatic animals would not be affected.

F.3.5. Aquatic Plant Analysis

F.3.5.1. Aquatic Plant Toxicity Summary

Table F-44 summarizes the toxicity of dicamba to aquatic plants (algal species and duckweed) 

derived from the U.S. EPA EFED assessment (U.S. EPA 2005).

Table F-44. Non-Target Aquatic Plant Toxicity of Dicamba Acid

Species % a.e. EC50/NOEC 

(mg a.e./L) Endpoints Affected

Duckweed (Lemna gibba) 89.5 >3.25 / 0.20 Frond production

Green Algae (Selenastrum capricornutum) 89.5 >3.7 / 3.7 Cell density

Blue-green Algae (Anabaena flos-aquae) 89.5 0.061 / 0.005 Cell density

Diatom (Navicula pelliculosa) 89.5 2.3 / 0.50 Cell density

Diatom (Skeletonema costatum) 89.5 0.493 / 0.011 Cell density

Source: U.S. EPA (2005)

F.3.5.2. Aquatic Plant Exposure Estimates

Exposure estimates for aquatic plants potentially exposed to dicamba are derived from GENEEC 

and PRZM/EXAMS modeling.
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F.3.5.3. Aquatic Plant Risk Quotient Calculations

For aquatic plant species, the acute risk quotient is calculated as follows:

Aquatic Plant RQacute =

Peak EEC (mg a.e./L)

EC50 (mg a.e./L)

EPA currently does not assess chronic risk to aquatic plants.

The lowest EC50 value from Table F-44 was used for the risk quotient calculation for aquatic plants. 

Table F-45summarizes the Tier I risk quotients for endangered aquatic plants exposed to dicamba 

derived using exposure estimates from GENEEC; Table F-46 summarizes the Tier II risk quotients

derived using PRZM/EXAMS for the 6-day interval maximum use pattern.

Table F-45. Tier I Risk Quotients for Aquatic Plants based on GENEEC Exposure 

Estimates for DGT Cotton and DT Soybean.

Toxicity 

Endpoint

(mg 

a.e./L)

Peak Peak Peak

1 lb/A 2 x 0.5 lb /A 4 × 0.5 lb/A

EEC

(ppm) RQ EEC(ppm) RQ EEC(ppm) RQ

Aquatic 

Plants 

(nonvascular)

nonlisted

EC50: 

0.061 0.0443 0.73 0.0334 0.548 0.0419 0.687

Aquatic 

Plants 

(vascular)

nonlisted

EC50: > 

3.25 0.0443 < 0.014 0.0334 <0.0103 0.0419 < 0.0129
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Table F-46. Tier II Risk Quotients for Aquatic Plants Based on PRZM/EXAMS Exposure 

Estimates using a 6-day interval maximum use pattern for DT Soybean and DGT Cotton 

(1.0 lb/A + 0.5 lb/A + 0.5 lb/A)

Application Scenario

Toxicity 

Endpoint

(mg a.e./L)

Peak (1-in-10-yr) 96 Hour (1-in-10-yr)

EEC

(ppm) RQ EEC (ppm) RQ

1.0 lb a.e./A + 0.5 lb a.e./A + 0.5 lb a.e./A – DT Soybean

Aquatic Plants 

(non-vascular) non-listed EC50: 0.061 0.0327 0.54 0.0308 0.50

Aquatic Plants 

(vascular) non-listed EC50: > 3.25 0.0327 <0.011 0.0308 <0.01

1.0 lb a.e./A + 0.5 lb a.e./A + 0.5 lb a.e./A – DGT Cotton

Aquatic Plants 

(non-vascular) non-listed EC50: 0.061 0.0416 0.68 0.0382 0.63

Aquatic Plants 

(vascular) non-listed EC50: > 3.25 0.0416 <0.013 0.0382 <0.012

F.3.5.4. Aquatic Plant Analysis Summary and Conclusions

The risk quotients for non-endangered aquatic vascular and non-vascular plants are below the LOC 

for all use patterns indicating that risk from exposure to dicamba following application to DGT 

cotton or DT soybean can be excluded from concern and, therefore, aquatic vascular and nonvascular plants would not be affected.

F.3.6. Terrestrial and Semi-Aquatic Plant Analysis

F.3.6.1. Terrestrial and Semi-Aquatic Plant Toxicity Summary

To assess the potential risk to terrestrial and semi-aquatic plants, the U.S. EPA uses plant toxicity 

data generated according to existing test guidelines. There are two kinds of studies used, a test 

designed to evaluate the potential injury to a plant before and just after emergence from the soil (i.e., 

seedling emergence, pre-emergence) and a test designed to evaluate the potential injury when applied 

directly to the plant foliage (i.e., vegetative vigor, post emergence). EPA guidelines give the option 

of using data from plants grown in the field or grown in the greenhouse. 

For dicamba, two sets of non-target plant studies have been submitted to the U.S. EPA; the first 

studies were completed in 1993 (Hoberg, 1993) using the Subdivision J guidance, and the second set 

of studies was completed in 2009 using the updated Series 850 and OECD guidelines (Porch et al., 

2009a, 2009b). See Table F-47 for a comparison of the methodology employed using the different 

guidelines. For the 2009 studies, the experiments were conducted in a greenhouse, and the test 

substance was the dicamba DGA salt formulation, Clarity (a BASF product), with the addition of 

0.125% of a non-ionic surfactant and 14 g/L of di-ammonium sulfate. The 1993 studies were 

conducted in a growth chamber, and the test substance for these studies was dicamba acid.
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Table F-47. Comparison of non-target plant testing methodology 

Subdivision J guideline

Dicamba Test I (Hoberg, 1993)

Current Series 850 Guideline

Dicamba Test II (Porch, 2009a, 2009b)

Silica sand Natural or artificial soil

OM = 0.11 – 0.17% Up to 1.5% OC ( approx 3% OM)

Growth chamber Growth chamber, glasshouse, semi-field 

1⁄4 strength AAP nutrient solution Fertility as needed based on controls

200 ml solution “added” to sand Surface application

Seeds planted 1 cm deep Seeding depth appropriate for seeds

Onion seedling survival in control = 83% Survival of at least 90% needed

30 ml test solution sprayed ( 1026 gal/A) Typical application volumes (10-100 gal/A) “not to exceed 

runoff”

NOEC not determined for all 1 dose below EC25, 1 dose above EC50, determine 

NOEC (or calculate EC05 if necessary)

The latter studies (Porch et al., 2009a, 2009b) were initiated at the request of the EPA following a 

review of the 1993 studies that occurred during the product reregistration process. In their review, 

EPA concluded that the initial non-target terrestrial plant studies were not adequate because a 

NOEC was not determined for the most sensitive endpoints in either study (U.S. EPA, 2005). In 

addition, the study reports from the initial studies (Hoberg, 1993) document numerous observations 

that cast doubt on the validity and interpretation of the test results. For example, the study reports 

note visual injury symptoms of brown leaf tips, necrosis, and chlorosis. However, it has been shown 

that these plant responses are different than typical sublethal plant symptoms associated with 

exposure to dicamba such as leaf curling, epinasty, thickened internodes, and shortened plants (Auch 

and Arnold, 1978; Weidenhamer et al.,1989).

It is likely that the observed plant responses in the 1993 studies were the result of unfavorable test 

conditions rather than the test material itself. The tip browning and necrosis observed in the studies 

were likely caused by excess salt accumulation in the leaf tips and leaf margins. The excess salt 

accumulation, in turn, was likely the result of growing the plants in silica sand, a medium with little 

or no buffering capacity, coupled with the use of a nutrient solution that was one-quarter strength 

AAP nutrient solution and applied daily without regard to nutritional requirements for the plants.142 

This continued application of nutrient solution likely resulted in the accumulation of excess salt in 

the leaf tips and leaf margins and in the desiccation and browning of the tissue.143 Another key test 

 

142 The 1993 study did not follow the most current guidance which requires that nutrient and fertilizer needs should be based on 

observations of the control plants. 

143 The fact that tip browning noted in the 1993 study was reported as occurring on corn, a plant that is not normally sensitive to 

dicamba effects, is a further demonstration that the effects observed were not dicamba-specific effects. 
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condition was the use of KNO3 in the media in place of NH4NO3. The use of KNO3 commonly 

leads to alkalization over time and plant chlorosis due to iron and magnesium deficiencies. 

The AAP medium was designed for use in hydroponic systems and in algal studies where the 

solution is replaced at regular intervals rather than allowed to accumulate in a closed container. 

There are also differences between the guidelines used in the 1993 study as compared to the current 

guidelines, thus calling into question the quality of the 1993 study: the previous use of growth 

chambers to grow plants versus the current use of greenhouses or field-grown plants; the previous 

planting of seeds from all species at the same depth (1 cm) versus the current guidance to plant 

seeds at a depth appropriate to the seed size; and the previous germination of seeds first in paper 

“rag dolls”, followed by transfer to pots, versus the current guidance to allow germination to occur 

in soil. 

Finally, it is notable that the test material used in 1993 was technical grade dicamba and not a typical 

end use product, i.e., a formulated product, as is currently required. 

In light of the discussion above, the results of the 2009 seedling emergence study are considered to 

be more indicative of the effects of dicamba when applied to plants pre-emergence (at the seedling 

and early growth stage) and to have been performed according to current test guidance. The 2009 

vegetative vigor study also reflects the current use of dicamba. As a result, the current analysis uses 

the data from these studies to assess potential effects of dicamba on non-target terrestrial plants.

Table F-48 summarizes the seedling emergence data (Porch, 2009b; MRID 47815101) and Table F49 summarizes the vegetative vigor data (Porch, 2009a; MRID 47815102) used in this analysis.
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Table F-48. 21-Day Seedling Emergence Endpoints for Dicamba DGA Salt

Species Taxon NOER

(oz/A)

NOER 

(lb a.e./A)

ER25 a

(oz/A)

ER25 b(lb 

a.e./A)

Measured 

Endpoint

Corn Monocot 64.0 2.00 > 64 > 2 NA

Onion Monocot 21.3 0.666 37.4 1.17 Height, dry weight

Ryegrass Monocot 21.3 0.666 63.8 2.0 Height, dry weight

Wheat Monocot 64.0 2.00 > 64 > 2 NA

Cabbage Dicot 21.3 0.666 59.9 1.87 Height, dry weight

Carrot Dicot 7.11 0.222 16.0 0.50 Height, survival

Lettuce Dicot 2.37 0.074 8.66 0.271 Dry weight

Oilseed rape Dicot 2.37 0.074 18.1 0.566 Dry weight

Soybean Dicot 2.37 0.074 4.53 0.142 Height, dry weight

Tomato Dicot 2.37 0.074 4.42 0.138 Dry weight

NOER = No Effect Rate, the highest application rate at which no measurable effects occurred

ER25 = Effective Rate that caused a 25% effect such as a 25% reduction in plant height

NA = not applicable, no injury evident

a Ounces per acre of the formulated product containing 4 lb acid equivalent of active ingredient per gallon

b Values used for risk quotient calculation are indicated in bold type.

Table F-49. 21-Day Vegetative Vigor Endpoints for Dicamba DGA Salt

Species Taxon NOER

(oz/A)

NOER b

(lb a.e./A)

ER25 a

(oz/A)

ER25 b

(lb a.e./A)

Measured 

Endpoint

Corn Monocot 64 2.000 > 64 > 2 NA

Onion Monocot 8 0.250 12.7 0.40 Dry weight 

Ryegrass Monocot 64 2.000 > 64 > 2 Dry weight

Wheat Monocot 8 0.250 16.4 0.51 NA

Cabbage Dicot 0.79 0.025 2.61 0.08 Dry weight

Carrot Dicot 0.79 0.025 22.5 0.70 Dry weight

Lettuce Dicot 0.074 0.00231 0.614 0.02 Dry weight

Oilseed rape Dicot 2.4 0.07500 15.7 0.49 Dry weight

Soybean Dicot 0.0082 0.000256 0.0194 0.00061 Height

Tomato Dicot 0.0082 0.000256 0.0286 0.00089 Dry weight

NOER = No Effect Rate, the highest application rate at which no measurable effects occurred

ER25 = Effective Rate that caused a 25% effect such as a 25% reduction in plant height or dry weight

NA = not applicable, no injury evident at the highest rate tested
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a Ounces per acre of the formulated product containing 4 lb acid equivalent of active ingredient per gallon

b Values used for risk quotient calculation is indicated in bold type.

F.3.6.2. Terrestrial and Semi-Aquatic Plant Exposure Estimates

EPA uses the TerrPlant model (U.S. EPA 2009b) as a Tier I model to determine EECs for terrestrial 

and semi-aquatic plants from runoff and drift. Consistent with guidance provided by the TerrPlant 

User Manual, application scenarios were considered separately without regard to application 

intervals. Two scenarios were considered, a single application of 1.0 lb a.e./A and a single 

application at 0.5 lb a.e./A of dicamba. The single application rate of 1.0 lb a.e./A is the proposed 

maximum rate for application prior to emergence of the crop. Such an application may be used to 

help prepare the seedbed for planting and to control initial weed infestations. This initial application 

prior to emergence may be followed by two subsequent applications of 0.5 lb a.e./A, at least six days 

apart (seven for DGT cotton, per the requirement on the proposed label) between emergence and 

seven days prior to harvest for DGT cotton and between emergence and the first reproductive 

flowering stages (R1) for DT soybean. The evaluation of risk associated with single applications is 

considered appropriate as a Tier I screening approach because such an approach assumes that the 

dicamba applied to the target field will move off-site to adjacent areas on the day of application with 

no degradation and no interaction with the soil and plant foliage. 

The EECs for terrestrial and semi-aquatic plants were calculated as described below, based on 

guidance regarding runoff values based on active ingredient solubility. The resulting EEC values are 

summarized in Table F-50.

Unincorporated ground application:

Drift = maximum application rate x 0.01

Runoff (dry areas) = maximum application rate x 0.05

Runoff (semi-aquatic areas) = maximum application rate x 0.05 X 10

Total = Drift + Runoff

Table F-50. Dicamba: TerrPlant EECs for Terrestrial and Semi-Aquatic Plants 

Application Rate 

(lb a.e./A)

EEC (lb a.e./A)

Runoff Spray

Drift

Total

Dry Areas Semi-Aquatic Dry Areas Semi-Aquatic

1.0 0.05 0.5 0.01 0.06 0.51

0.5 0.025 0.25 0.005 0.03 0.255

F.3.6.3. Terrestrial and Semi-Aquatic Plant Risk Quotient Calculations

For terrestrial plant species, the acute risk quotient is calculated as follows:
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Terrestrial and SemiAquatic Plant RQacute 

=

EEC (lb/A)

NOER (lb/A; endangered plants) or 

ER25 (lb/A; non-endangered plants)

EPA currently does not assess chronic risk to terrestrial plants.

Table F-51 and Table F-52 summarize the resulting risk quotients for terrestrial and semi-aquatic 

plant species potentially exposed to drift and sheet runoff (Dry), drift and channelized runoff (Semiaquatic), or drift only from terrestrial applications of dicamba at 1.0 lb a.e./A and 0.5 lb a.e./A, 

respectively. Risk quotients for runoff exposure utilize effects data from the seedling emergence 

study (Table F-48), while risk quotients for spray-drift-only exposure utilize effects data from the 

vegetative vigor study (Table F-49).

Table F-51. Tier I Risk Quotients for Terrestrial and Semi-aquatic Plants for a 1 lb a.e./A 

Application 

Plant Type Listed Status

Risk Quotient a

Dry b Semi-Aquatic b Spray Drift c

Monocot non-listed <0.1 0.44 <0.1

Dicot non-listed 0.43 3.70 16.39

Bold numbers indicate that the LOC (1.0) is exceeded.

a

 RQ = EEC Table F-50)/or ER25 (for non-listed species). 

b Considering the lowest monocot and dicot ER25 values from the seedling emergence study (Table).

c

 Considering the lowest monocot and dicot ER25 values from the vegetative vigor study (Table F-49 Table).

Table F-52. Tier I Risk Quotients for Terrestrial and Semi-aquatic Plants at the 0.5 lb 

a.e./A Application

Plant Type Listed Status

Risk Quotient a

Dry b Semi-Aquatic b Spray Drift c

Monocot non-listed <0.1 0.22 <0.1

Dicot non-listed 0.22 1.85 8.20

Bold numbers indicate that the LOC (1.0) is exceeded.

a RQ = EEC (Table F-50)/or EC25 (for non-listed species). 

b Considering the lowest monocot and dicot ER25 values from the seedling emergence study (Table F-48).

c

 Considering the lowest monocot and dicot ER25 values from the vegetative vigor study (Table F-49).
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F.3.6.4. Terrestrial and Semi-Aquatic Plant Summary and Conclusions

F.3.6.4.1. Conclusions based on TerrPlant

The RQ values calculated for terrestrial and semi-aquatic monocot plant species resulting from 

estimated exposure to run-off and spray drift are below the LOC of 1 for all use patterns, indicating 

that risk from exposure to dicamba used on soybean or cotton with the DT trait can be excluded 

from concern, and therefore, terrestrial and semi-aquatic monocot plant species would not be 

affected. For terrestrial dicot plant species subject to sheet runoff, the LOC is also not exceeded at 

the 1.0 lb a.e./A and 0.5 lb a.e./A application rates, indicating that risk resulting from dicamba 

exposure from sheet runoff at the indicated rates can be excluded from concern, and therefore, nonlisted dicot plant species would not be affected.

For terrestrial and semi-aquatic dicot plants exposed only to spray drift and for semi-aquatic dicot 

plants subject to channelized runoff (and drift), the LOC is exceeded at the 1.0 lb a.e./A and 0.5 lb 

a.e./A application rates. However, as discussed later in this Appendix, Monsanto plans to 

implement a web-based tool, Pre-Serve, in conjunction with application requirements on the label,

to address potential sensitive areas that may be downwind of the application site. In any event, 

before approving the proposed labels for dicamba use on DGT cotton and DT soybean, EPA must 

ensure that there will be no unreasonable adverse effects on the environment.

F.3.6.4.2. Conclusions from a more refined exposure assessment of semi-aquatic dicot 

plants

Because dicamba has been registered for use as a herbicide since 1967, there are extensive surface 

water monitoring data available. Water monitoring data for dicamba in surface water were compiled 

from publicly available information sources; there were of 21,626 surface water monitoring records 

identified between 1990 and 2010.144 Sources of surface water monitoring data include:

 USDA Pesticide Data Program (PDP) 

Website: http://www.ams.usda.gov/AMSv1.0/PesticideDataProgram 

 USEPA STORET (Storage and Retrieval)

Website: http://www.epa.gov/storet/

 USGS National Water Quality Assessment (NAWQA)

Website: http://water.usgs.gov/nawqa/

 USGS National Water Information System (NWIS)

Website: http://waterdata.usgs.gov/nwis

 

144 Additionally, the USGS National Water Quality Assessment (NAWQA) database was also queried for surface water monitoring 

results for dicamba in 2011 and 2012. A total of 162 samples were analyzed for dicamba during this period and all results were 

non-detect with levels of quantitation ranges from 0.04 – 0.06 μg a.s./L.
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 Various State water quality monitoring programs

Of the available 21,626 records for dicamba, 3,431 (15.9%) were reported as detected concentrations 

(having a dicamba concentration above the analytical detection limit). Summary statistics for the 

3,431 reported detection records are provided in Table F-53. The 90th percentile of detected 

dicamba concentrations in the water quality monitoring database is 0.34 μg a.e./L (Table F-53).

145

 

Table F-53. Summary Statistics for Detected Dicamba Concentrations Reported in Water 

Quality Monitoring Databases.

Surface Water Concentration (μg 

a.e./L)

n 21,626

Detects 3,431

10th Percentile 0.020

25th Percentile 0.060

Median 0.077

75th Percentile 0.15

90th Percentile 0.34

Detects: First Sample Date Feb 1, 1990

Detects: Last Sample Date June 8, 2010

Overall, dicamba was not detected in more than 89% of the samples. For samples with detected 

dicamba levels, the minimum, median, 90th percentile and maximum concentrations are provided in 

Table F-54. When the water monitoring data were evaluated to assess historical dicamba 

concentrations in major corn production states during periods when dicamba would typically have 

been applied for agricultural uses, and for which maximum concentrations of dicamba in surface 

water would be expected, the 90th percentile of dicamba detections during 1994–1998, 

corresponding to the peak dicamba usage period, and across the entire monitoring period (1990 –

2010) was 0.74 and 0.88 μg/L (Table F-54), respectively. The maximum level of dicamba detected 

in surface water between 1990 and 2010 was 17 μg/L.

146

Table F-54. Summary Statistics for Detected Dicamba Concentrations (μg a.e./L) in 

Surface Water in Major Corn Growing States (April – July sampling dates)

1990-1993 1994-1998 1999-2004 2005-2010 1990-2010

n 588 1,362 2,443 1,033 5,426

 

145 When all data between 1990 and 2010 were considered (n = 21,626), the 90th percentile value is 0.062 μg a.s./L (details not 

presented).

146 For the analysis for major corn production states, when all data between 1990 and 2010 were considered (n = 5,426), the 90th

percentile value is 0.040 μg a.e./L (details not presented).
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Number of Detects 146 206 222 14 588

For Detects 

only

Minimum 0.010 0.0080 0.010 0.030 0.0080

Median 0.20 0.25 0.29 0.29 0.25

90th Percentile 1.4 0.74 0.94 0.050 0.88

Maximum 17 9.4 3.3 0.94 17

These 90th percentile water concentrations were then compared to the lowest NOER for the 2009 

seedling emergence study by assuming that NOER in lb a.e./A is the result of water in the EPA 

standard pond drying down and being deposited on a soil surface with the same area as the pond 

without further dicamba degradation.147 The dicamba concentration in the pond water is then 

calculated using these assumptions. The aquatic EEC that corresponds to an RQ of 1 for the 

lowest NOER was determined to be 4.16 μg a.e./L. When all surface water monitoring data 

available for the period 1990 – 2010 are considered, 4.16 μg a.e./L corresponds to a percentile of 

99.9%. When only detected concentrations are considered, 4.16 μg a.e./L corresponds to a 

percentile of 99.7%. Similarly, using the EC25 of the most sensitive dicot in the seedling emergence 

study, the aquatic EEC that would result in an RQ of 1 is 7.75 μg a.e./L.148 A concentration of 7.75 

μg a.e./L corresponds to a percentile of 99.9% when all data available for the period 1990 – 2010 are 

considered. When only detected concentrations are considered, 7.75 μg a.e./L corresponds to a 

percentile of 99.8%. The surface water monitoring data indicate that dicamba concentrations are 

very rarely present in surface water at concentrations that may pose a risk to semi-aquatic plants. 

F.4. Threatened and Endangered Species Analysis for Dicamba, DT Soybean and DGT 

Cotton

Congress passed the Endangered Species Act (ESA) of 1973, as amended, to prevent extinctions 

facing many species of fish, wildlife, and plants. The purpose of the Endangered Species Act (ESA) 

is to provide a means for conserving the ecosystems upon which endangered and threatened species 

depend and a program for the conservation of such species.149 To implement the ESA, the U.S. Fish 

and Wildlife Service (USFWS) works in cooperation with the National Marine Fisheries Service 

(NMFS); other Federal, State, and local agencies; Tribes; non-governmental organizations; and 

private citizens. Before a plant or animal species can receive the protection provided by the ESA, it 

must first be added to the Federal list of threatened and endangered wildlife and plants. 

 

147The NOEC value for the most sensitive broadleaf plant species in the dicamba DGA salt seedling emergence study (Porch et al.,

2009b) is 0.074 lb a.e./A for tomato. To calculate the concentration in the EPA standard pond that would result in this rate 

being deposited on soil upon drying of the pond without degradation of the dicamba present, the NOEC value is converted 

from lb a.e./Ato kg a.e./ha and then divided by 20 x 106, the volume of the pond in liters

148 The EC25 value for the most sensitive broadleaf plant species in the dicamba DGA salt seedling emergence study (Porch et al., 

2009b) is 0.138 lb a.e./A for tomato.

149 Endangered Species Act of 1973 (as amended through Public Law 107-136), Section 2(b).
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A species is added to the list when the USFWS and/or NMFS determined it to be endangered or 

threatened because of any of the following factors: 

 The present or threatened destruction, modification, or curtailment of its habitat or range; 

 Overutilization for commercial, recreational, scientific, or educational purposes; 

 Disease or predation; 

 The inadequacy of existing regulatory mechanisms; and 

 The natural or manmade factors affecting its survival. 

In accordance with the ESA, once an animal or plant is added to the list, protective measures apply 

to the species and its habitat. These measures include protection from adverse effects of Federal 

activities. 

Section 7 (a)(2) of the ESA requires that Federal agencies, in consultation with USFWS and/or the 

NMFS, ensure that any action they authorize, fund, or carry out is not likely to jeopardize the 

continued existence of a listed species or result in the destruction or adverse modification of 

designated critical habitat. It is the responsibility of the Federal agency taking the action to assess 

the effects of their action and to consult with the USFWS and NMFS if it is determined that the 

action “may affect” listed species or critical habitat. To facilitate APHIS’ ESA consultation process, 

APHIS met with the USFWS from 1999 to 2003 to discuss factors relevant to APHIS’ regulatory 

authority and effects analysis for petitions for nonregulated status, and developed a process for 

conducting an effects determination consistent with the Plant Protection Act of 2000 (Title IV of 

Public Law 106-224). This process is described in a decision tree document, which has been 

included in recent Environmental Assessments and the Final Environmental Impact Statement for 

glyphosate-tolerant H7-1 sugar beet (USDA-APHIS, 2011a; 2012b). APHIS has used this process to 

help fulfill its obligations and responsibilities under Section 7 of the ESA for GE regulatory actions.

F.4.1. Monsanto’s Technical Analysis Follows EPA’s Guidance, and Relies on the “Best 

Information Available” Regarding Threatened and Endangered Species

This portion of Appendix F provides a summary of the final steps in a multi-step approach that has

been utilized to evaluate the potential effects on federally-listed threatened or endangered (“listed”) 

plant and animal species from the use of the herbicide dicamba on DT soybean and DGT cotton. 

This analysis follows the procedures described in the Overview of the Ecological Risk Assessment

Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency, Endangered

and Threatened Species Effects Determinations (US EPA, 2004), as well as methods utilized in more

recent threatened and endangered species effects determinations conducted by the U.S. 

Environmental Protection Agency (“USEPA”) for a number of active ingredients in assessing their 

potential effects on the California red-legged frog.

150

 The project involved an analysis of the 

potential proximity of relevant land use to sub-county locations of listed species that had been 

 

150 Effects determinations are available at http://www.epa.gov/oppfead1/endanger/litstatus/effects/redleg- frog/index.html
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identified as “requiring further analysis” in a county-level analysis (Frank and Kemman, 2012, 2013a, 

b, c). 

For both threatened or endangered (“TES”) animals and plants, Monsanto first conducted the type 

of screening-level analyses set forth in OPP’s Overview Document. Using the maximum use pattern set 

out in the proposed label at issue, Monsanto estimated exposure of designated animal and plant taxa 

using current EPA environmental exposure models. Monsanto then utilized these conservative 

exposure estimates, in conjunction with effects values for species of designated taxa derived from 

toxicity tests meeting EPA quality standards, to calculate risk quotients (“RQs”). If the RQ value, 

calculated by dividing the estimated exposure by the appropriate toxicity value, was less than the 

Level of Concern (“LOC”) for TES in the designated taxa, Monsanto concluded that risks to a 

taxonomic category could be excluded from concern because of the conservative nature of the 

screening-level assessment assumptions and, therefore, that there would be no effect on the relevant 

threatened or endangered species.151 Monsanto undertook a similar analysis at the screening level to 

evaluate potential indirect effects on threatened and endangered species and potential effects on 

critical habitat, thereby enabling Monsanto to exclude from concern such effects on certain species.

Again, following EPA’s Overview Document, Monsanto next conducted a more detailed, countylevel analysis for the animal taxonomic groups (and associated listed species) that could not be 

excluded from concern at the screening level, and for all listed plant species. This analysis identified: 

(i) all counties indicated as having soybean or cotton farms in the last three Ag. Census (1997, 2002, 

and 2007) as having “potential” for soy or cotton production, and (ii) all threatened or endangered 

species with reported presence within those counties (or in adjacent counties) in the taxonomic 

groups evaluated. A “no effect” determination could then be made for species “co-occurrences” 

based on a number of exclusions (e.g., habitat, not of concern, proximity, diet, and feeding).

For animals, this analysis expressly recognized and took into account the fact that the animals at 

issue may move from location to location. Specifically, the feeding and diet exclusions for animals 

are based on inherent characteristics of the individual endangered species and are not in any way 

impacted by where the species is physically present. For both animals and plants, the “not of 

concern” designation is provided only where the species has not been reported in the county in the 

past 35 years, or where FWS does not include the county on the list of counties where the species is 

known or believed to occur in the county (and no other source indicates species presence), or where 

the species has been delisted. The habitat exclusion applies only where the individual endangered 

species’ habitat is not suitable for agricultural production152 and reported locations of the species are

 

151 “If assumptions associated with the screening level action area result in RQs that are below the listed species LOCs, a ‘no effect’ 

determination conclusion is made with respect to listed species in that taxa, and no further refinement of the action area is

necessary.” EFED Reregistration Chapter for Dicamba/Dicamba Salts, p. 72. 

152 For example, the silver rice rat (located in Monroe County, Florida) typically use three zones that are delineated by their salinity 

and topography: (1) low intertidal areas, (2) salt marsh flooded by spring or storm tides, and (3) buttonwood transitional areas 

that are slightly more elevated and only flooded by storm tides. In general, rice rats use mangrove habitats primarily for foraging, 

while higher-elevation salt marshes are used for nesting and foraging. Crop agriculture is not practiced near these 

shoreline/marshy areas. 
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not near land suitable for agricultural production.153 The proximity exclusion (for animal species)

only applies when land relevant for soybean or cotton production is not within a relevant species’ 

“home range” – i.e., the area within which the species lives and travels, based on information from 

FWS and other sources.154 Finally, for listed plants that are monocots, a product-property 

determination applies based on the results of the screening-level analysis described above.

For listed plant species co-occurrences not excluded from concern based on the county-level 

analysis, a refined sub-county analysis was undertaken to assess the proximity of reported species 

observations to relevant land use for soybean or cotton production. In addition, mitigation 

measures were proposed, where necessary, to prevent effects on such plant species. The pertinent 

proximity distance evaluated for each species observation to relevant land use for soybean and 

soybean production, or cotton and cotton production, was initially and conservatively set at 450 

feet.155 For species observations within 450 feet of relevant land use, guidance both from 

NatureServe and State endangered species programs, and in some cases from the U.S. Fish & 

Wildlife Service, was used to define the boundaries of what we call “Use Limitation Areas 

(ULAs).”156

A number of specific points are important to understand how ULAs function. The boundaries of 

the ULAs are based on data gathered from a variety of sources, including NatureServe, the U.S. Fish 

& Wildlife Service, and the States. The NatureServe Multijurisdictional Database (“MJD”)157

includes threatened and endangered species location data at the sub-county level. It may also 

include additional information, including date of last observation and observation notes. Monsanto 

supplemented the NatureServe MJD with State-specific information from sources such as the 

California Natural Diversity Database, published by the California Department of Fish and Game. 

Data was also obtained from New Jersey and, North Carolina. Frequent environmental litigants 

have demanded that EPA use these species-location data. See Center for Food Safety, Comments on 

EPA Reregistration of Atrazine, August 22, 2013 (“NatureServe provides detailed life history 

 

153 Suitability for agricultural production was based on the National Land Cover Database 2001 and 2006, Class 81 (Pasture/Hay) and 

Class 82 (Cultivated Crops). 

154 For example, the proximity exclusion for the Arroyo toad includes the following rationale: based on sub-county location 

information, reported locations of the Arroyo toad in certain counties were not within 28 miles of land relevant for cotton 

production. This species, however, only has a home range of approximately 1.2 miles, with a travel distance of just 0.3 to 1.2 

miles. Moreover, every species with a “proximity” exclusion also had at least one other applicable exclusion.

155 The distance of 450 feet is a conservative distance that is greater than the distance from the edge of the dicamba application area 

to a point at which an effect on soybean plant height is no longer observed, when the proposed FIFRA label application 

requirements for the dicamba diglycolamine salt are employed. Utilizing the EPA screening assessment approach as described in 

the Overview Document, soybeans have been demonstrated to be the most sensitive species to the effects of dicamba, and plant 

height was the most sensitive endpoint in the vegetative vigor study. Effects on soybean plant height have, therefore, been used 

to determine a distance beyond which dicamba would not impact TE plants. 

156 Monsanto also adhered to the Overview Document in its assessment of plant-dependent and plant-obligate species, as well as lands 

identified as critical habitat. Where necessary to protect listed species that rely upon a specific plant and or critical habitat, 

Monsanto will include relevant use instructions for applicators / growers on Pre-Serve. 

157 The NatureServe MJD is available to Monsanto under a licensing agreement with the FIFRA Endangered Species Task Force of 

which Monsanto is a member.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 794 of 946

information, including spatial distribution, for native species across the United States. In addition, 

many State governments collect detailed information on non-game species through their State 

Wildlife Action Plans.”). This is exactly what Monsanto has done—it has utilized and relied upon 

these data to devise appropriate measures to avoid impacts to threatened and endangered species. It 

has also utilized a wide range of land use data to conservatively ascertain land relevant to soybean 

and/or cotton production. Likewise, it relied upon extensive toxicity testing, exposure data, stateof-the art modeling, and other relevant scientific and commercial data in conducting its assessment. 

Furthermore, the NatureServe, State, and other species and location data relied on by Monsanto 

form the basis for ULAs contained within Pre-Serve, the convenient and simple web and hotlinebased tool that guides growers/applicators through a checklist to determine whether their fields fall 

within ULAs. Where fields do fall within ULAs and appropriate habitat is present, the web and 

hotline-based system will reiterate to the growers the mandatory steps (as specified on the proposed 

label, which is currently pending before EPA) that must be taken to avoid effects on pertinent 

species.

F.4.2. Reports Submitted

In lengthy and detailed submissions to EPA over the past two years, Monsanto has established the 

scientific predicate for its conclusions that specific measures will preclude the dicamba applications 

at issue from having any effect on threatened or endangered species. Specifically, Monsanto has 

submitted the following reports on DT soybean: 

 Honegger JL. 2012a. Information to Support an Endangered Species Assessment for 

Dicamba Use in Dicamba-Tolerant Soybeans: Overview for Plant Taxa. Monsanto Technical 

Report MSL-23721. MRID 48900401;

 Frank AR, Kemman R. 2012. Information to Support an Endangered Species Assessment 

for Dicamba Use in Dicamba-Tolerant Soybeans: A County-Level Analysis for Plant Taxa. 

Monsanto Technical Report MSL-23442. MRID 48900402;

 Carr KH, Leopold VA. (2012a) Information to Support an Endangered Species Assessment 

for Dicamba Use in Dicamba-Tolerant Soybeans. Sub-County Proximity Analysis for Listed 

Plants: Western U.S. States and Hawaii. Monsanto Technical Report MSL-22548. MRID 

48900403;

 Carr KH, Leopold VA. (2012b) Information to Support an Endangered Species Assessment 

for Dicamba Use in Dicamba-Tolerant Soybeans. Sub-County Proximity Analysis for Listed 

Plants: Eastern U.S. States. Monsanto Technical Report MSL-22549. MRID 48900404.

 Carr KH, Leopold VA. 2013. Information to Support an Endangered Species Assessment 

for Dicamba Use in Dicamba-Tolerant Soybeans. Sub-County Proximity Analysis for Listed 

Plants: Iowa Monsanto Technical Report MSL-24694. MRID 49093201.

 Wright JP, Schuler LJ, Carr KH, Orr TB, Honegger JL. 2013. Information to Support an 

Endangered Species Assessment Dicamba Use in Dicamba-Tolerant Soybeans: An 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 795 of 946

Evaluation of Potential Exposure and Biological Effects. Monsanto Technical Report MSL24665. MRID 49022301

 Honegger JL. (2013) Information to Support an Endangered Species Assessment for 

Dicamba Use in Dicamba-Tolerant Soybeans: Overview of an Evaluation of Potential 

Exposure and Biological Effects. Monsanto Technical Report MSL-24667. MRID 49022401.

 Schuler LJ, Leopold VA, Fredricks TB, and Carr KH. 2013a. Information to Support an 

Endangered Species Assessment for Dicamba Use in Dicamba-Tolerant Soybeans: Refined 

Analysis for Terrestrial Animals. Monsanto Technical Report MSL-24666. MRID 49022402. 

 Frank AT, Kemman R. 2013). Information to Support an Endangered Species Assessment 

for Dicamba Use in Dicamba-Tolerant Soybeans: A County-Level Analysis for Animal Taxa 

(2013 Update). , Monsanto Technical Report MSL-24678. MRID 49022403.

 Schuler LJ, Fredricks TB, Levine SL and Carr KH. 2013b. Information to Support an 

Endangered Species Assessment for Dicamba Use in Dicamba-Tolerant Soybeans: Indirect 

Effects Analysis. Monsanto Technical Report MSL-24677. MRID 49093202;

 Honegger JL. (2012b) Overview of Proposed Approach to Address the Potential for Off-site 

Movement from Use of Dicamba on Dicamba-Tolerant Soybeans. Monsanto Technical 

Report MSL0024401. MRID 48892302;

 Orr, TB, Wright, JP, Honegger, JL. (2012) Summary of Investigations of the Potential for 

Off-Site Movement through the Air of the Herbicide MON 54140 Following Ground 

Applications. Monsanto Study Number RPN-2012-0201. Monsanto Technical Report 

MSL0024124. MRID 48876001;

 Wright JP, Schuler LJ, Carr KH, Orr TB, Honegger JL. 2013. Information to Support an 

Endangered Species Assessment Dicamba Use in Dicamba-Tolerant Soybeans: An 

Evaluation of Potential Exposure and Biological Effects. Monsanto Technical Report MSL24665. MRID 49022301;

 Orr, TB, Wright, JP, Honegger, JL. (2012) Summary of Investigations of the Potential for 

Off-Site Movement through the Air of the Herbicide MON 54140 Following Ground 

Applications. Monsanto Study Number RPN-2012-0201. Monsanto Technical Report 

MSL0024124. MRID 48876001;

 Sall, et. al., Measurement of the Volatile Flux of Dicamba under Field Conditions using the 

Theoretical Profile Shape Method, Mar. 25, 2013. 

Monsanto also has submitted the following reports on DGT cotton:158 

 

158 Monsanto anticipates completing two additional reports on DGT cotton in December 2013.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 796 of 946

 Honegger JL, Schuler LJ, Wright JP, Fredricks TB, Carr KH, Orr TB. 2013. Information to 

Support an Endangered Species Assessment for Dicamba Use in Cotton Containing the 

Dicamba Tolerance Trait: An Evaluation of Potential Exposure and Biological Effects. 

Monsanto Technical Report MSL0025079. MRID 49221301;

 Frank AR, Kemman R. (2013) Information to Support an Endangered Species Assessment 

for Dicamba Use in Cotton Containing the Dicamba Tolerance Trait: A County-Level 

Analysis for Plant Taxa. Monsanto Technical Report MSL0025083. MRID 49221306;

 Carr KH, Orr TB. 2013. Information to Support an Endangered Species Assessment for 

Dicamba Use in Cotton Containing the Dicamba Tolerance Trait. Potential Exposure and 

Effects for Listed Plants (Screening Level through Proximity Analysis). Monsanto Technical 

Report MSL0025084. MRID 49221307;

 Honegger JL. 2013. Information to Support an Endangered Species Assessment for 

Dicamba Use in Cotton Containing the Dicamba Tolerance Trait: Overview of an 

Evaluation of Potential Exposure and Biological Effects for Animals. Monsanto Technical 

Report MSL0025078. MRID 49221302;

 Frank AR, Kemman R. 2013. Information to Support an Endangered Species Assessment 

for Dicamba Use in Cotton Containing the Dicamba Tolerance Trait: A County-Level 

Analysis for Animal Taxa. Monsanto Report No. MSL0025081. MRID 49221303;

 Schuler LJ, Fredricks TB, Tompsett-Higley AR, Carr KH. 2013c. Information to Support 

an Endangered Species Assessment for Dicamba Use in Cotton Containing the Dicamba 

Tolerance Trait: Refined Analysis for Terrestrial Animals. Monsanto Technical Report 

MSL0025080. MRID 49221304;

 Schuler LJ, Fredricks TB, Tompsett-Higley AR, Carr KH. 2013d. Information to Support 

an Endangered Species Assessment for Dicamba Use in Cotton Containing the Dicamba 

Tolerance Trait : Indirect Effects Analysis for Terrestrial Animals. Monsanto Technical 

Report MSL0025082. MRID 49221305.

F.4.3. Effects on Threatened or Endangered Plant Species From Dicamba Use on DT 

Soybean

F.4.3.1. Endangered Species Exposure and Effects Analysis 

F.4.3.1.1. Screening-Level Analysis

An initial analysis of the potential for exposure and effects to all taxa (including plants) from 

dicamba use in DT soybean based on the use pattern pending at EPA was conducted (Wright et al., 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 797 of 946

2013) using the EPA deterministic risk quotient approach (USEPA, 2004).159 The use pattern for 

dicamba utilized in this analysis was a pre-emergence application at a rate of 1.0 lb dicamba acid 

equivalents per acre (a.e/A) followed by two post-emergence applications each at a rate of 0.5 lb 

a.e./A with a 6-day interval between the pre-emergence application and the first post-emergence 

application, and a 6-day interval between the two post-emergence applications, with all applications 

being made using ground application equipment.160 The 6-day application intervals utilized in this 

analysis are anticipated to be shorter than the intervals actually used in practice, since a grower is 

anticipated to wait at least 7 days before deciding to make a subsequent application in order to allow 

evidence of dicamba efficacy to develop. 

For aquatic plants, initial exposure estimates using the above described use pattern were based on 

the standard EPA exposure models GENEEC 2.0 and PRZM (3.12.2)/EXAMS (2.98.04.6) and 

toxicity effects endpoints taken from the EPA Environmental Fate and Effects Division (EFED) 

Science Chapter for the Reregistration Eligibility Decision for dicamba (USEPA, 2005). 

For terrestrial plants, initial exposure estimates using the above described use pattern were based on 

the standard EPA exposure model TerrPlant 1.2.2 and default assumptions; toxicity effects 

endpoints were taken from EPA guideline studies conducted by BASF under an EPA data call-in 

(Porch et al., 2009a and 2009b161). 

The conclusion from this initial analysis (Wright et al., 2013), based on risk quotients (RQs) being 

less than the EPA Levels of Concern (LOCs), is that dicamba use on DT soybean would not affect 

threatened and endangered plant species in the following taxa:162

 Aquatic vascular plants

 Monocotyledonous terrestrial plant species (monocots)163,164

 

159 This approach calculates a risk quotient (RQ) by dividing the Estimated Environmental Concentration (EEC) by the appropriate 

toxicity endpoint, and then compares that value with the appropriate Level of Concern LOC). The LOC is established by EPA 

policy as the criteria used by EPA in comparison to the calculated risk quotient (RQ) to assess the potential for a pesticide use to 

cause adverse effects to non-target organisms.

160 The proposed dicamba label for DT soybeans will not permit aerial application.

161 New studies were required by EPA because previous studies did not meet current regulations requiring the use of formulated 

product for these studies. This new testing resulted in a more conservative endpoint for the vegetative vigor study and 

confirmed field observations of relative sensitivity for the seedling emergence study. 

162 “If assumptions associated with the screening level action area result in RQs that are below the listed species LOCs, a “no 

effect” determination conclusion is made with respect to listed species in that taxa, and no further refinement of the action area 

is necessary.” EFED Reregistration Chapter for Dicamba/Dicamba Salts, p. 72. 

163 According to EPA methodology (USEPA 2004), risk to non-target plants is assessed only outside the application area.

164 There is no distinction between acute and chronic exposure durations for plants in the EPA assessment process for endangered 

species.
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Although the RQ for listed aquatic non-vascular plants exceeded the LOC, additional analysis was 

not conducted because there are no federally listed non-vascular aquatic plants. The RQ for nonlisted aquatic non-vascular plants was less than the LOC, indicating that other taxa of threatened and 

endangered species would not incur indirect effects as a result of effects on non-listed non-vascular 

aquatic plants.

These conclusions for aquatic plants are consistent with the risk conclusions presented in the EFED 

science chapter for dicamba reregistration (USEPA, 2005 and 2009). 

The conclusion for monocots is supported by more recent nontarget plant studies with a typical 

dicamba end use product containing the diglycolamine salt of dicamba.165 These studies were 

required by EPA during the reregistration process to assess the phytotoxicity of an end-use product 

containing the diglycolamine salt. Only endpoints for dicamba acid were available for consideration 

in the EFED science chapter (USEPA, 2005 and 2009), for which it was concluded that the RQ 

exceeded the LOC. Toxicity endpoints for the diglycolamine salt were not available at that time to 

calculate an RQ for comparison with the LOC (Porch et al., 2009a and 2009b).166 Using the noobserved-effect endpoints from these 2009 studies and the EPA model TerrPlant to calculate 

exposure and risk quotients, the RQs for monocots were below the LOC (Wright et al., 2013), and 

thus result in a conclusion that monocots would not be affected by use of the diglycolamine salt of 

dicamba on DT soybean. The levels of concern considered by EPA for threatened and endangered 

(listed) species risk assessments are given in Table F-55.

Table F-55. EPA Levels of Concern for Threatened and Endangered Plant Species 

(USEPA, 2004)

Risk Presumption Calculation for Risk Quotient Level of Concern

Terrestrial and Semi-Aquatic Plants

Acute Risk EEC/EC05 or NOAEC 1.0

Aquatic Plants

Acute Risk EEC/EC05 or NOAEC 1.0

For threatened and endangered terrestrial plant species in classes other than monocotyledons, 

further analysis is required.

F.4.3.1.2. Refined Analysis for Listed Plants Considering County-Level Information

Consistent with EPA guidance found in the Overview Document (USEPA, 2004), if screening-level 

assessments do not result in a “no effect” determination, EPA does not then conclude that an 

 

165 M1691, the formulation for which the new use on DT soybeans is under review, contains dicamba in the form of the 

diglycolamine salt.

166 The new study was conducted under the OPPTS 850.4225 draft guideline, which is very similar to the current OECD nontarget 

plant guideline. The results are considered to be more representative of effects that would be anticpated in the field than 

previous studies because of an improved study design.
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herbicide “may affect” threatened and endangered species; rather, more refined assessments must be 

conducted to ascertain if any effects are expected to occur. Based on this guidance, a more detailed 

evaluation of the locations of threatened and endangered plant species relative to potential areas of 

soybean production, and, therefore, potential dicamba use was undertaken.167 

First, the co-occurrence of threatened and endangered plant species and the production of soybeans 

was evaluated at the county level. Listing status168, species habitat, species observation history in the 

county, and proximity data to soybean production at the county level were evaluated to determine: 

(1) which species in which counties can be excluded from further evaluation; and (2) which require 

further evaluation. This process is referred to as the “county-level analysis” (Frank and Kemman 

2012) and is discussed in more detail in Section IV.C.F.4.3.2. 

F.4.3.2. County-Level Analysis: Co-occurrence of Listed Plant Species in Crop Production 

Areas

The procedures used in the county-level analysis to identify counties containing threatened or 

endangered species that require further evaluation are described in detail in Frank and Kemman 

(2012). The U.S. counties where soybean production was reported were identified using available 

data from the U.S. Census of Agriculture.169 Census data from 1997, 2002, and 2007 were utilized to 

identify these counties. This information was supplemented with soybean production data available 

from the California Department of Pesticide Regulation. Counties without soybean production, but 

adjacent to counties with soybean production were also identified. In total, there were 2,728 counties 

considered in this analysis (2,198 soybean counties, 530 adjacent counties). 

In the identified counties, available county-level presence information for threatened or endangered 

plant species was evaluated, using county-level location information compiled by the FIFRA 

Endangered Species Task Force (FESTF) in the FESTF Information Management System (IMS).170 

Of the 2,728 counties initially considered, there were 1,274 counties in 48 states with soybean 

production (or adjacent to soybean production) and reported presence of listed plants species. 

 

167 Overview Document (USEPA, 2004), p. 69. 

168 Listing status refers to whether the species is classified as threatened, endangered, no longer considered threatened or 

endangered (delisted), etc.

169 Although this analysis considered counties where soybean production was reported, a review of the available data demonstrates 

that almost every county in the eastern two thirds of the U.S. is included. Thus, it is very unlikely that any counties with soybean 

production were missed using this approach. 

170 The FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act) Endangered Species Task Force (FESTF) Information 

Management System 2.7 (IMS) (referred to as the “FESTF IMS”) was developed in order to meet the legal obligations of its 

member companies to submit data required by EPA/OPP under FIFRA (as described in Pesticide Registration Notice 2000-2) 

in support of the members’ registration and re-registration actions. The purpose of the IMS is to meet the data requirements in a 

manner that significantly improves the consistency, quality, availability and use of existing information on threatened and 

endangered species and pesticide use. http://www.festf.org/visitors/default.asp. Sources of information for the county-level 

species information in the IMS include: a dataset provided to the FESTF by the U.S. EPA in June 2003, county-level plant 

species location data from NatureServe’s Multi-Jurisdictional Database (MJD) licensed to the FESTF, and the United States Fish 

& Wildlife Service (USFWS) endangered species by county lists.
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These counties represented 477 listed plant species. There were 2,658 species-county co-occurrence 

records considered across all plant taxa. 

In these counties, each species was evaluated with respect to the current listing status, county-level 

locations, species habitat requirements, and plant classification in order to determine whether 

exposure to dicamba from use on DT-soybean could potentially result in effects to the species. 

Some listed species could be removed from concern for effects based on exclusions that currently 

exist and are documented. Exclusions that have been employed include change in species listing 

status, not present due to extirpation171, historic observations (no observations since 1977 or earlier),

habitat not in proximity to agriculture, product properties related to plant taxa selectivity172, or 

species not in proximity to agriculture for other reasons. Table F-56, taken from Frank and 

Kemman (2012), provides a summary of the results of the county-level analysis after exclusions have 

been considered. Species assigned a Not of Concern determination have information from a U.S. 

Fish & Wildlife Service (USFWS) or NatureServe source, or a state or local expert to indicate that 

the species is not present in the county or is not in proximity to soybean production.

Table F-56. Summary of Species Determinations for this Analysis 

Determination Type Number of 

States

Number of 

Counties

Number of 

Species

Number of 

Co-Occurrences

Not of Concern 41 517 115 721a

Product-Property 38 486 54 554

Habitatb 35 269 237 532

Species Management Practicec 8 13 7 13

Requires Further Analysis 38 545 183 838

Total 2,658

Total distinctd 48 1,274 477

a Of the 721 co-occurrences with a Not of Concern determination, 705 of the determinations were supported by information 

from the U.S. Fish & Wildlife Service county list or a regional office expert; 16 determinations were supported by information 

from NatureServe or a state or local species expert.

b For species assigned a Habitat determination, supporting information regarding proximity of species’ locations to agricultural land 

relevant for soybean production is provided in Carr and Leopold (2012a, 2012b).

c Species is present on public or private land protected by conservation plans or agreements.

d More than one determination type may be assigned to different county-level co-occurrences of the same species. Therefore, the 

total number of species (or counties) for all determination types is more than the total number of distinct species (or counties). 

 

171 An extirpated species is defined as “a species no longer surviving in regions that were once part of its range” 

(http://www.fws.gov/midwest/endangered/glossary/index.html).

172 A product property exclusion is based on results of screening level risk analysis indicating that the risk quotient for 

monocotyledonous plants is below the Level of Concern and, therefore, monocots would not be affected by dicamba use on DT 

soybean.
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After considering co-occurrences for which exclusions apply, county-species co-occurrences remain 

in 38 states, in a total of 545 counties, and for 183 species, which require further analysis. As 

described in the EPA Overview Document (USEPA, 2004), the next step in the analysis is to 

consider these co-occurrences at the sub-county level evaluating the proximity of the species 

observation and the land areas that have the potential to be used for soybean production.173

F.4.3.3. Sub-County Plant Species Observations versus Land Use Proximity Analysis

The analysis of proximity of relevant land use to sub-county locations of threatened or endangered 

plant species that have been identified as “requiring further analysis” in the county-level analysis 

(Frank and Kemman, 2012) is described in detail in Carr and Leopold (2012a and 2012b). A 

summary of the spatial information used and the proximity analysis is provided in the sections that 

follow.

F.4.3.3.1. Land Use Information

For the contiguous U.S. and Hawaii, land cover data considered in this analysis were obtained from 

the National Land Cover Dataset (NLCD 2001) (minimum mapping unit: 30-meters). Data for the 

2001 NLCD were collected from 1994-1998 and represent the best comprehensive collection of 

national land use and land cover information for the U.S. The spatial data (resolution [minimum 

mapping unit]: 30 meters) was converted from raster format to vector format for Class 81 

(pasture/hay) and Class 82 (cultivated crops). These two classes were considered “relevant land 

use” for this analysis, since land designated as cultivated crops could potentially be used for DTsoybean production, and some pasture/hay fields could be converted to cultivated cropland. 

In some situations, available satellite imagery was used to verify the proximity of species 

observations to agricultural lands (a verification of the NLCD 2001 land use classification). The 

source of satellite imagery was the either the “ESRI_Imagery_World_2D” map service (available 

online from ESRI Inc.174), or the Bing map service.175 

F.4.3.3.2. Species Locations

FESTF Multi- Jurisdictional Database (MJD)

Threatened and endangered plant species location data at a sub-county level were obtained from the 

FIFRA Endangered Species Task Force Multi-Jurisdictional Database (FESTF MJD; NatureServe 

 

173 Overview Document (USEPA, 2004), p. 69. 

174 Description of ESRI imagery source: Accessed through ESRI Inc, via the ArcMap GIS software. Described on the following 

website: http://www.arcgis.com/home/item.html?id=10df2279f9684e4a9f6a7f08febac2a9

175 Description of Bing imagery source: Accessed through ESRI Inc, via the ArcMap GIS software.

http://www.esri.com/software/arcgis/arcgis-online-map-and-geoservices/bing-maps
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2009, 2012). The FESTF MJD consists of a “licensed dataset” drawn from NatureServe’s MultiJurisdictional Database (MJD) licensed to FESTF.176

 The MJD species observation records included 

additional data fields, such as date of last observation and observation notes; this information was 

evaluated and utilized when relevant to the proximity assessment.

The MJD location data were provided as polygons (areas representing where a listed plant species 

was observed; referred to as a “species observation”). The spatial dataset was provided in a format 

suitable for analysis and display using Geographic Information System (GIS) software. Polygons for 

listed dicots were are small as 10 square meters and as large as 700 square kilometers.

For the purposes of this analysis, species observations were considered “historic” if the “last 

observed date” for the observation (as reported by NatureServe in the MJD 2009 dataset) was prior 

to 1977.177 Additional observation-specific data available in the MJD 2009 dataset (e.g. field notes) 

were examined to identify observations that are noted to be “historic” or “extirpated.” In some 

cases, species with observations later than 1976 were flagged as “extirpated.” In situations of 

historic or extirpated species observations, no further analysis was conducted. 

State-Specific Location Data

New Jersey, Pennsylvania, and Maryland state heritage programs did not contribute data to the 

NatureServe program from which the FESTF MJD 2009 dataset was derived; where sub-county 

species location information was needed for these states, information was requested directly from 

the state heritage programs (New Jersey), or prior Monsanto company work products (Maryland; 

prepared when the program was a participant in the NatureServe program) were relied upon. In 

addition,

 For California, the California Natural Diversity Database (CNDDB, California Department 

of Fish and Game) was used as a supplement to the MJD 2009 dataset, to evaluate species 

presence at the sub-county level when the MJD 2009 dataset did not provide current species 

records. 

 For North Carolina, a refined species location dataset was obtained in May 2010 from the 

North Carolina Natural Heritage (NCNH) Program; this information was used to refine 

proximity conclusions derived from the FESTF MJD 2009. At the request of the NCNH 

Program, the refined location information was used for the definition of proposed use 

limitation areas in North Carolina.

 

176 Under the terms of the FESTF license with NatureServe, the sub-county threatened and endangered species location data are 

confidential information available only to FESTF member companies, companies having satisfied their data compensation 

obligations, and the U.S. EPA’s Office of Pesticide Programs. Information based on the sub-county species location data may 

be shared with cooperating federal and state agencies for regulatory decision-making related to endangered species assessments 

for Monsanto products. 

177 A time period for observations beginning in 1977 is considered a conservative time period for this analysis.
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 Species location information for New Jersey was obtained from the New Jersey Department 

of Environmental Protection (NJDEP) and Office of Natural Lands Management (ONLM). 

These data were provided in a grid format – a grid layer with each grid section representing 

approximately 0.5 square miles. A corresponding table indicated which species were present 

in each grid section. 

 For Washington State, prior Monsanto work products based on an earlier version of the 

FESTF dataset (FESTF MJD 2006) were considered for proximity analysis, since the MJD 

2006 dataset contained higher resolution location information than the MJD 2009 dataset, 

and no new observation records for the plant species of interest were present in the MJD 

2009 dataset (when compared to the MJD 2006 dataset). 

F.4.3.3.3. Proximity Analysis Process

When the sub-county species location data was considered, the 838 county-species co-occurrences 

requiring further analysis resulted in 4,973 sub-county species observations from the FESTF MJD 

and state heritage program datasets; additional less well-defined species location information was 

available from other sources. Proximity distances from each observation (polygon) in the MJD 2009 

dataset to NLCD Class 81 (Pasture/Hay) and Class 82 (Cultivated Crops) land area are available, and 

were used to evaluate potential proximity to land suitable for soybean production. As discussed 

above, both of these NLCD classes are considered relevant. The FIFRA Endangered Species Task 

Force used the MJD 2009 dataset to prepare a database entitled “FESTF 7/10/09 MultiJurisdictional Database (MJD) species occurrence/land cover proximity database”, and Classes 81 

and 82 were included in this database. From this database, the nearest distance of an observation to 

relevant land use in a soybean production county was extracted. 

The proximity distance evaluated for each species observation to relevant land use for soybean 

production was 450 ft. The distance of 450 feet is a conservative distance that is greater than the 

distance from the edge of the dicamba application area to a point at which an effect on soybean 

plant height is no longer observed, when the proposed FIFRA label application requirements for the 

dicamba diglyolamine salt are employed (Orr, et al., 2012, Honegger, 2012b). Utilizing the EPA 

screening assessment approach as described in the EPA Overview Document (USEPA, 2004)178, 

soybeans have been demonstrated to be the most sensitive species to the effects of dicamba ((Porch 

et al.: 2009a, 2009b), and plant height was the most sensitive endpoint in the vegetative vigor study. 

(Wright et al. (2013)).

F.4.3.3.4. Proximity Findings

Results of the proximity analysis indicate that there are 1,657 species observations representing 87 

species in 27 states and 303 counties that are within 450 feet of a land area where soybeans could 

potentially be grown and dicamba applied (Table F-57, Data Row 4). In the detailed reports that 

describe the proximity determination (Carr and Leopold, 2012a and 2012b), the sub-county analysis 

 

178 Overview Document (USEPA, 2004), p. 31.
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is described by county, with the counties being grouped by state, and the states being organized 

according to the U.S. Fish and Wildlife Service region. 

According to the proposed mandatory FIFRA label requirements for application of the dicamba 

diglycolamine salt formulation on DT soybean, a no-spray buffer will be required when threatened 

and endangered plant species are downwind from a dicamba application area to DT soybean. The 

proposed label, which is currently pending before EPA, also mandates that the grower and/or 

applicator consult a hotline or a web-based application that is under development and will be 

implemented prior to product launch; this web-based application will ensure that the grower and/or 

applicator knows when threatened and endangered plant species may be located within potential 

proximity of land where soybeans could be grown and dicamba applied, and thus knows whether a 

no-spray buffer is required for each individual dicamba application. These label restrictions, and/or 

any other measures imposed by EPA, will ensure that there is no effect on threatened and 

endangered species from the use of dicamba on DT soybean. Because the locations of threatened 

and endangered species observations in the FESTF MJD are confidential by agreement with 

NatureServe, an area larger than the listed species observation must generally be defined to protect 

the species location information. These larger areas have been termed “potential use limitation 

areas.” The process of defining these areas is described in Section IV.C.4.

F.4.3.4. Sub-county Areas for Potential Use Limitation and Mitigation Measures

Monsanto defined potential areas around threatened and endangered plant species locations where 

label restrictions related to threatened and endangered species may be required. These areas have 

been defined to ensure species protection. The three components needed for implementation of 

potential use limitation areas are: 

1. definition of the sub-county areas that include threatened and endangered plant species 

locations, as well as additional area so that the listed species are protected from 

disturbance or collection by rare plant enthusiasts;

2. development of habitat descriptions for the listed plant species within these areas; and 

3. definition of label requirements that provide listed plant species protection from 

potential dicamba exposure.

F.4.3.4.1. Sub-county Descriptions of Potential Use Limitation Areas

For the observations of threatened or endangered plant species that overlap or are within 450 feet of 

relevant land uses, the next step of the analysis is to identify these species observations in such a way 

that appropriate label restrictions can be applied. Because the sub-county species location 

information is confidential under the terms of the NatureServe licensing agreement, the species 

locations cannot be disclosed to the public (see Footnote 43). Therefore, each of the state-level 

agencies or programs that provided sub-county species location data to NatureServe was contacted 

to determine whether it was acceptable for the sub-county species location information to be

available to the public with only an additional 450 feet distance applied as a “resolution distance” 

around the area identified as the species location. In some cases, this distance was acceptable. In 

most cases, the state programs requested that a larger area be identified to provide an additional 

layer of conservatism regarding the location of the species.
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Proximity analysis tools available in GIS software were used to add the additional area requested by 

the state heritage programs to the species observation area. These “buffered” observations were 

then further expanded so that potential use limitation boundaries could be described using 

surrounding surface features, such as roads, creeks, rivers, and railroads, and land survey boundaries 

(sections), where available. Maps depicting each listed plant species observation with proximity to 

relevant land use and the subsequently derived potential use limitation area are presented in the 

confidential attachments of Carr and Leopold (2012a and 2012b). 

F.4.3.4.2. Habitat Descriptions 

Habitat descriptions have been developed for each threatened or endangered plant species for which 

areas of potential use limitation have been proposed. These descriptions were developed from plant 

species information available from government and academic sources. Within the areas described 

for potential use limitation, mandatory label restrictions are only considered necessary when the 

habitat for the listed species is present. These habitat descriptions are included in the detailed 

reports (Carr and Leopold, 2012a and 2012b).

F.4.3.4.3. Label Restrictions

A proposed label has been submitted for the dicamba diglycolamine salt formulation for the new use 

on DT soybeans. This proposed label, which is currently pending before EPA, includes mandatory 

application requirements to minimize off-site movement. These requirements include 

implementation of a buffer when listed plant species are downwind from application areas. A 

further explanation of these measures to reduce off-site movement is presented in Honegger 

(2012b).

F.4.3.4.4. Overall Process for Sub-county Analysis

Polygons depicting threatened and endangered plant species locations that are within 450 feet of 

agricultural land where soybeans could potentially be grown, based on Ag Census information, have 

been increased in size and geographically mapped to allow public presentation of areas where listed 

plant species may be present. In addition, while not making species names public, brief, clearlyworded habitat descriptions have been developed for each potential use limitation area to allow the 

applicator / grower to ascertain whether suitable habitat for the species is present in the area 

downwind from the planned application area. Because of the need to increase the size of the 

publicly identified area beyond the boundaries of the listed species location, it is proposed that only 

if the appropriate habitat is present would the buffer mandated by the label apply. 

F.4.3.4.5. Web-Based System to Communicate Use Limitations 

To provide a convenient mechanism to present the locations of potential use limitation areas to 

growers / applicators, a web-based system similar to the system developed for glyphosate (www.PreServe.org) is under development for dicamba. This web site will guide growers and applicators 

through a simple step-wise process to determine whether their fields fall within potential use 

limitation areas – areas where threatened or endangered plant species and/or habitat for those 

species may be present. Where fields do fall within potential use limitation areas and appropriate 

habitat is present, the web-based system will reiterate to the growers the mandatory steps (as 

specified on the label) that must be taken to reduce exposure to threatened and endangered plant 
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species and avoid effects on survival, growth, and reproduction of these species. As an alternative 

to using the web-based program, growers/applicators will be able to call a hotline to obtain this 

information.

F.4.3.5. Conclusions

In the EFED ecological risk assessment conducted for dicamba reregistration (USEPA, 2005), using 

a screening-level assessment, EPA scientists concluded that a “no effect” determination can be 

made for all dicamba uses for vascular aquatic plant species. The potential for adverse effects to 

non-vascular aquatic plants and terrestrial and semi-aquatic plants could not be excluded based on 

the EPA screening-level assessment, the initial phase of analysis. However, since there are currently 

no listed non-vascular aquatic plants and non-listed non-vascular aquatic plants have an RQ below 

the LOC, this taxon does not require further investigation at this time. Recognizing that screeninglevel analysis is only the first step in evaluating impacts on threatened and endangered species, the 

EFED Science Chapter (USEPA, 2005) indicates that “additional information on the biology of 

listed species, the locations of these species, and the locations of the use sites ... could be 

considered along with available information on the fate and transport properties of the pesticide to 

determine the extent to which screening assumptions regarding an action area apply to a particular 

listed organism.” 

The above discussion summarizes the conclusions of four other reports (Wright et al., 2013; Frank 

and Kemman, 2012; and Carr and Leopold, 2012a and 2012b) that utilize some of the refinements 

described by EPA in the previous paragraph and in the Overview Document (USEPA, 2004) to 

evaluate the potential for adverse effects to listed plant species. When the properties of dicamba 

and species-specific information are taken into account, these reports demonstrate that 

monocotyledonous terrestrial and semi-aquatic plants outside the treated area also would not be 

affected (Wright et al., 2013). The other three reports listed above coupled with the proposed 

application requirements on the label provide a mechanism to prevent exposure that otherwise may 

affect other threatened and endangered terrestrial plant species. 

Table F-57 summarizes the results of each step in this process. The analysis was initiated by

considering all counties in the United States where soybean farms have been reported and in which 

threatened or endangered plant species have been observed. The presence of a single soybean farm 

in any one of three Censuses of Agriculture spanning a ten-year period resulted in inclusion of that 

county in the analysis. In addition, listed species from counties adjacent to soybean production 

counties were also included in the analysis. Exclusions for habitat, protections, proximity analysis, 

and observation notes were used to identify areas and species where a potential for effects from 

exposure to dicamba could not be excluded. These areas were defined with precision to protect 

species and not reveal their exact location. By providing a mechanism to identify these areas to 

applicators and growers, required application practices on the herbicide label can be used to avoid 

exposure that would affect these species.
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Table F-57. Numbers of counties, listed plant species, and observations involved in the 

analysis for DT-soybeans at major steps in the analysis

Analysis Category

Number of:

States Counties Listed Plant 

Species

Species

Observations 

Soybean production counties & adjacent counties b 50 2,728 -- --

Soybean production counties & adjacent counties 

that have presence of listed plant species b

48 1,274 477 --

Species-county co-occurrences evaluated for 

potential proximity (450-ft) to relevant land use c

38 545 183 4,973 a

Species observations with potential proximity to 

relevant land use d

27 303 87 1,657 a

Proposed use limitation areas (ULA) e 27 307 87 --

f

a Numbers represent species observation data available from the FESTF MJD dataset or from other Heritage Program sources. 

These species observation numbers do not include species location information obtained from other sources.

b As reported in Frank and Kemman (2012). 

c These co-occurrences are the records assigned a “Requires Further Analysis” determination in Frank and Kemman (2012). 

d These values exclude species observations that are historic (pre-1977), extirpated, or not at risk from agriculture.

e Includes counties where proposed use limitation areas extend into that county from an adjacent county.

f Not reported since the proposed ULAs includes areas where species observations are not available.

F.4.4. Effects on Threatened or Endangered Animal Species From Dicamba Use on DT 

Soybean

F.4.4.1. Endangered Species Exposure and Effects Analysis

F.4.4.1.1. Screening Level Analysis

An initial analysis of the potential for exposure and effects to all taxa from dicamba use in DT 

soybean based on the use pattern pending at EPA was conducted (Wright et al., 2013) using the 

EPA deterministic risk quotient approach (USEPA, 2004).179 The use pattern for dicamba utilized in 

this analysis was a pre-emergence application at a rate of 1.0 lb dicamba acid equivalents per acre 

(a.e/A) followed by two post-emergence applications each at a rate of 0.5 lb a.e./A with a 6-day 

 

179 This approach calculates a risk quotient (RQ) by dividing the Estimated Environmental Concentration (EEC) by the appropriate 

toxicity endpoint, and then compares that value with the appropriate Level of Concern (LOC). The LOC is established by EPA 

policy as the criteria used by EPA in comparison to the calculated risk quotient (RQ) to assess the potential for a pesticide use to 

cause adverse effects to non-target organisms.
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interval between the pre-emergence application and the first post-emergence application, and a 6-

day interval between the two post-emergence applications, with all applications being made using 

ground application equipment.180 The 6-day application intervals utilized in this analysis are 

expected to be shorter than the intervals actually used in practice, since a grower is expected to wait 

at least 7 days before deciding to make a subsequent application in order to allow evidence of 

dicamba efficacy to develop.

Initial exposure estimates using the above described use pattern were based on standard EPA 

exposure models and default assumptions; toxicity effects endpoints were taken from the EPA 

Environmental Fate and Effects Division (EFED) Science Chapter for the Reregistration Eligibility 

Decision for dicamba (USEPA, 2005). The conclusion from this initial analysis, based on risk 

quotients (RQs) being less than the EPA Levels of Concern (LOCs), is that dicamba use on DT 

soybean would not affect threatened and endangered species in the following taxa:

 Fish, aquatic phase amphibians, and aquatic invertebrates (acute or chronic exposure)

 Birds, terrestrial-phase amphibians, and reptiles (chronic exposure)

 Mammals (acute exposure)

 Insects181

These conclusions for aquatic animals, birds, mammals and insects are consistent with the risk 

conclusions presented in the EFED science chapter for dicamba reregistration (US EPA, 2005 and 

2009).

The levels of concern considered by EPA for threatened and endangered (listed) species risk 

assessments are given in Table F-58.

 

180 The proposed dicamba label for DT soybeans will not permit aerial application.

181 RQ calculations for insects are based on acute contact exposure. The RQ for the honey bee, as a surrogate for terrestrial 

invertebrates, was not a definitive value. Since there was no mortality in the acute contact exposure study, a definitive LD50 could 

not be determined. The resulting RQ was <0.12. However, since there was no mortality in the study, and the dose tested was 

more than seven times greater than upper bound maximum default residue value for arthropods calculated from T-REX using 

the dicamba- specific foliar decline value, the initial assessment concluded that terrestrial invertebrates would not be affected by 

dicamba use on DT-soybeans. This is consistent with the dicamba science chapter (USEPA, 2005a) conclusion that dicamba is 

practically non-toxic to bees.
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Table F-58. EPA Levels of Concern for Threatened and Endangered Species (USEPA, 

2004)

Risk Presumption Calculation for Risk Quotient Level of Concern

Birds

Acute Risk EEC/LC50 (application of a liquid) or LD50/ft2 or 

LD50/day (application as a granule, bait, or treated 

seed)

0.1

Chronic Risk EEC/NOAEC 1.0

Wild Mammals

Acute Risk EEC/LC50 (application of a liquid) or LD50/ft2 or 

LD50/day (application of a granule, bait, or treated 

seed)

0.1

Chronic Risk EEC/NOAEC 1.0

Terrestrial Invertebrates

Acute Risk EEC/LD50 0.05

Aquatic Animals

Acute Risk EEC/LC50 or EC50 0.05

Chronic Risk EEC/MATC or NOAEC 1.0

F.4.4.1.2. Refinement to the Screening Level Analysis - Use of Dicamba-specific Foliar 

Residue Values

Consistent with EPA guidance found in the Overview Document (USEPA, 2004), if screening-level 

assessments do not result in a “no effect” determination, EPA does not then conclude that an 

herbicide “may affect” threatened and endangered species; rather, more refined assessments must be 

conducted to ascertain if any effects are expected to occur. Accordingly, for threatened and 

endangered animal species and the exposure durations for which the risk quotient exceeded the 

LOC in the screening level analysis (acute exposure for birds, amphibians and reptiles, and chronic 

exposure for mammals), refined exposure estimates were developed utilizing measured dicamba 

residues on pasture grasses182 as representative residues for the short grass component of animal 

diets (Wright et al., 2013). These data were from residue studies conducted under Good Laboratory 

Practices by dicamba registrants and were used to estimate dicamba-specific residues for the grass 

components of animal diets183, instead of using the EPA default residue values based on the Kenaga 

nomogram (Hoerger and Kenaga, 1972) as revised by Fletcher (1994). In addition, a Monsanto 

soybean residue study and a grass residue study, and a wheat residue study, included forage sampling 

at several time points soon after application. From these studies, the rate of decline of dicamba 

 

182 Residue values from these studies were converted to values expressed as parts per million per pound dicamba acid from residues 

values for application rates of 0.5, 1.0, and 2.0 lb a.e./A for grasses.

183 The ratio of Kenaga residue values for tall vs. short grass was used with the measured pasture grass residue value to calculate a 

corresponding tall grass residue value.
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residues on soybean, grass, and wheat foliage could be determined, and the time required for 

dissipation of 50 percent of the Day Zero residues (DT50) calculated.184 The Overview Document 

(USEPA, 2004)185 indicates that chemical-specific foliar dissipation values can be used for multiple 

application exposure modeling for wildlife; accordingly, as a conservative assumption, the longest of 

the representative dicamba-specific foliar DT50 values for these three crops (5.63 days, for pasture 

grass) was used in the calculation of the dicamba-specific residues for chronic exposure. For grass 

and broadleaf dietary items, both mean and upper bound residue values186 were considered in the 

evaluation; these levels are suitable to estimate realistic (mean) and worst case (upper bound) levels 

of exposure. A comparison of the default upper bound residue values and dicamba-specific upper 

bound residue values is given in Table F-59.

Table F-59. Comparison of Default Kenaga Residues and Dicamba-specific Residues in 

Food-Items 

Maximum dicamba residues in food items (ppm a.e.) based on 

a 1 lb a.e./A pre-emergence application followed by two sequential 

post-emergence 0.5 lb a.e./A applications

Short 

Grass Tall Grass Broadleaf Plants

Fruits/ 

Pods/Seeds Arthropods

Using upper bound Kenaga residues & default foliar DT50 (35 days)

Day 0 (after 1st application) 240.0 110.0 135.0 15.0 94.0

Maximum residuea(after 3rd

application)

415.8 190.6 233.9 26.0 162.9

Using upper bound Kenaga residues & dicamba-specific foliar DT50 (5.63 days)

Day 0 and Maximum residuea

(after 1st application) 240.0 110.0 135.0 15.0 94.0

Using Dicamba-specific maximum measured residues (short and tall grass) & foliar DT50 (5.63 days)

Day 0 and Maximum residuea 

(after 1st application) 179.0 82.0 135.0 15.0 94.0

Using Dicamba-specific refined maximum measured residues (90th percentile value for short and tall 

grasses) & foliar DT50 (5.63 days)

Day 0 and Maximum residuea 131.0 60.0 135.0 15.0 94.0

 

184 For the pasture grass and wheat residue studies, there were over 50 treatments per study for which a DT50 value could be 

calculated. In accordance with US EPA guidance, the 90th percentile upper confidence limit of the mean DT50 value was selected 

as an appropriate DT50 value to use for calculation of residue decline for these crops. For the soybean residue study only six 

treatments were available to calculate DT50 values; thus, the maximum value was considered to represent residue decline in 

soybean forage.

185 Overview Document (USEPA, 2004), pg. 13.

186 Considering the number of measured residue values available for pasture grasses to calculate the upper bound residue, for 

chronic exposures, use of a refined maximum residue value (90th percentile value) was still considered a “worst case” 

conservative approach and is consistent with probabilistic approaches outlined in ECOFRAM (1999).
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(after 1st application)

a Using the default foliar DT50, the highest residue occurs immediately after the third application. Using the dicamba-specific

DT50, the highest residue occurs immediately after the first application.

These refined residue values for dietary items were considered when using the EPA model T-REX 

(v1.5.1) for the calculation of risk quotients and subsequent comparison to LOCs for acute 

exposures to birds, terrestrial amphibians, and reptiles, and for chronic exposures to mammals.187 

Risk quotients for chronic exposure to mammals calculated using refined maximum measured upper 

bound residues slightly exceed the LOC for small and medium-sized mammals consuming short 

grass or broadleaf plants; however, utilizing mean residue values as a further refinement, risk 

quotients are all below the LOC (Table F-60) leading to a conclusion of no effect on these species. 

This is consistent with the finding in the EFED Science Chapter for dicamba (USEPA, 2005) and 

the revised RED (USEPA, 2009) for a single application rate of 1.0 lb a.e./A. Because there will be 

at most only three applications per year and dicamba dissipates rapidly, an individual small- or 

medium-sized mammal will not chronically consume foliage containing maximum residue levels 

from dicamba-treated fields. Therefore, reliance on dicamba-specific Day 0 mean residue values is 

also a conservative dietary exposure estimate for chronic exposure that is expressly countenanced by 

EPA.188 Nonetheless, a refined county-level analysis was conducted for chronic exposure to 

mammals.

 

187 The T-REX model is not designed to allow modification of the dietary food item residues. Thus, the dicamba-specific residues 

reported in Table F-59 were considered in the risk quotient calculations by applying a correction factor to the estimated 

environmental concentrations (EEC) values computed using the standard T-REX model for a single 1-lb/A application.

188 Overview Document (USEPA, 2004), p. 40. 
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Table F-60. Risk Quotients for Chronic Exposure for Mammalian Species Based on 

Dicamba-Specific Residue Values and DT50.

Diet Mammal Size 

(g)

Risk Quotienta,b 

using Upper Bound 

Residues

Risk Quotienta

using Mean Residues

Short Grass

15 1.26 0.75

35 1.08 0.64

1000 0.57 0.34

Tall Grass

15 0.58 0.32

35 0.49 0.27

1000 0.26 0.15

Broadleaf Plants

15 1.30 0.43

35 1.11 0.37

1000 0.60 0.20

Fruits/Pods

15 0.14 0.07

35 0.12 0.06

1000 0.07 0.03

Arthropods

15 0.91 0.63

35 0.77 0.54

1000 0.41 0.29

Seeds

15 0.03 0.02

35 0.03 0.01

1000 0.02 <0.01

a Dicamba-specific refined residue values based on a 1 lb a.e./A application rate were 131, 60.0, 135.0, 15.0, 94.0 and 15.0 mg 

a.e./kg diet, respectively, for upper bound values for short grass; tall grass; broadleaf plants; fruits/ pods; arthropods; and seeds, 

and 77.9, 33.0, 45.0, 7.0, 65.0 and 7.0 mg a.e./kg, respectively, for mean residues. The dicamba-specific residue decline DT50 of 

5.63 days instead of the EPA default value of 35 days was also used in determining the peak residue value resulting from the 

three sequential applications.

b Numbers with Bold font indicate the RQ exceeds the LOC (1.0).

With respect to birds, analyses were performed using maximum measured dicamba residue values 

(Table F-59) for dose-based RQ calculations for acute exposure. The following could be excluded 

from concern (and, therefore, no effects would be expected to occur): birds of all sizes consuming 

only fruits/pods or seeds and large birds consuming tall grass or arthropods. Small and mediumsized birds consuming broadleaf plants, arthropods or grasses and large birds consuming short grass 

or broadleaf plants required further analysis. RQ values are presented in Table F-61. Refined 

analyses were conducted for birds for which the dose-based RQ values exceeded the LOC; however, 

this was a conservative approach since the subacute dietary-based RQ values, based on maximum 

measured upper bound residues (Table F-59), are all well below the LOC (0.1); except for birds 
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consuming a short grass diet. The short grass RQ (<0.12) is not definitively below the LOC; 

however, considering that the toxicity value used in the dietary assessment (>1522 mg/kgdiet) is 

actually an unbounded NOEC value from the bobwhite quail study, there would be no effects from 

short-term exposure to dicamba used on DT-soybeans.189

Because birds are the surrogate species for terrestrial phase amphibians and reptiles, further analysis 

was also conducted to ensure that amphibians and reptiles could be excluded from concern for 

adverse effect.

Table F-61. Risk Quotients for Acute Exposure to Birds Using Maximum Measured 

Dicamba Residues and Dicamba-specific Residue Decline Values 

Diet

Acute RQs: (Dose-based EEC/adjusted LD50)a

Upper Bound Residues

20 g

Small

100 g

Medium

1000 g

Large

Short grass 1.08 0.48 0.15

Tall grass 0.49 0.22 0.07

Broadleaf plants 0.81 0.36 0.12

Fruits/pods 0.09 0.04 0.01

Arthropods 0.57 0.25 0.08

Seeds 0.02 <0.01 <0.01

a Bold numbers indicate the RQ exceeds the LOC (0.1).

F.4.4.1.3. Refined Analysis Considering Species County-level Location

Certain sizes of threatened and endangered birds, amphibians, reptiles, and mammals had risk 

quotients exceeding the LOC as a result of the use of dicamba on DT soybean based on a default 

exposure analysis or an analysis using refined residue and residue decline values. Consistent with 

guidance set forth in the EPA Overview Document190, a more detailed evaluation of the locations of 

these threatened and endangered species relative to potential areas of soybean production was 

undertaken. 

 

189 The toxicity value (>1522 mg/kgdiet) used to calculate the RQ is a concentration in feed at which no effect was observed rather 

than a concentration at which 50% mortality would be predicted. The short grass EEC from Table F-59 is 179 mg/kgfeed. This 

estimated concentration on short grass that birds might be consuming is less than one eighth of the dietary concentration at 

which no effects were observed; therefore, there will be no effect on these species from short-term exposure to dicamba used on 

DT-soybeans.

190 Overview Document (USEPA, 2004), p. 69.
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First, the co-occurrence of threatened and endangered species and the production of soybeans was 

determined at the county level. For completeness, all threatened and endangered avian, amphibian, 

reptile, and mammalian species were included in the county-level analysis (including species 

proposed for listing, but excluding wholly aquatic species). Listing status191, species habitat and 

proximity data to soybean production at the county-level were evaluated for these identified species 

to determine which species in which counties can be excluded from further evaluation and which 

require further evaluation. This process is referred to as the “county-level analysis” (Frank and 

Kemman, 2013) and is discussed in more detail in Section IV.D.2 below. The sub-county location 

of threatened and endangered species observations and land relevant for soybean production was 

also considered for some species. This proximity evaluation is discussed in Section IV.D.3.

F.4.4.1.4. Refined Analysis Considering Species Biological Characteristics

Next, the Overview Document provides that – for those threatened and endangered species (avian, 

reptile, amphibian (terrestrial-phase), and mammalian) that require further evaluation – each species 

be considered individually to determine whether it can be excluded from concern for potential 

effects based on body weight or dietary considerations. Accordingly, for these animal species, 

refined risk quotient calculations were performed considering individual species body weight, food 

type and food intake rate, as described in Section IV.D.4 and in Schuler et al. (2013a), and consistent 

with EPA guidance found in the Overview Document (USEPA, 2004). Based on these refined 

county-level analyses, as discussed below, individual animal species were excluded from concern, 

and, therefore, would not be affected by dicamba use on DT soybeans.

F.4.4.2. County-level Analysis: Co-occurrence of Listed Species in Crop Production Areas

The procedures used in the county-level analysis to identify counties containing threatened or 

endangered species that require further evaluation and are described in detail in Frank and Kemman 

(2013a). The U.S. counties where soybean production was reported were identified using available 

data from the U.S. Census of Agriculture. Census data from 1997, 2002 and 2007 were utilized to 

identify counties with reported soybean farms.192 Any county with a reported soybean farm (i.e. with 

a crop of “soybeans for beans”) was considered in this analysis. 193 This information was 

supplemented with soybean pesticide application data available from the California Department of 

Pesticide Regulation for the years 2005-2007. Counties without soybean production, but adjacent to 

 

191 Listing status refers to whether the species is classified as threatened, endangered, no longer considered threatened or 

endangered (delisted), etc.

192 Conducted every five years, the USDA Census of Agriculture provides a detailed picture of U.S. farms and ranches and the 

people who operate them. It is the only source of uniform, comprehensive agricultural data for every state and county in the 

United States. The farm and acreage information for the 1997 census year was taken from the 2002 Census of Agriculture 

(USDA, 2004), which reports soybean information for both 1997 and 2002 census years.

193 This analysis assumed that the reported presence of a single soybean farm in any of the last three Censuses (1997, 2002, and 

2007) was an indicator that the county contained land suitable for soybean production. Moreover, a review of the available data 

demonstrates that almost every county in the eastern two thirds of the U.S. is included (see Frank and Kemman 2013a). Thus, it 

is unlikely that any counties with soybean production were missed using this approach.
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counties with soybean production were also identified. In total, there were 2,728 counties considered 

in this analysis (2,198 soybean counties, 530 adjacent counties). 

In the identified counties, available county-level presence information for threatened or endangered 

avian, reptile, amphibian, and mammalian species was evaluated, using county-level location 

information compiled by the FIFRA Endangered Species Task Force (FESTF) and available in the 

FESTF Information Management System (IMS).194 Species that were wholly aquatic (e.g. whales) 

were not included. Of the 2,728 counties initially considered, there were 2,418 counties with listed 

species in the taxa of interest for dicamba and where soybeans are produced (including counties 

adjacent to counties where soybeans are produced). These counties reflect the reported presence of 

139 distinct species in 49 states (all states except Alaska). There were 5,744 species/county cooccurrence records considered across all animal taxa evaluated. In these counties, each species was 

evaluated with respect to the current listing status, county-level locations, species biology, species 

habitat requirements, and (when possible) species proximity to land relevant for soybean production, 

in order to determine whether exposure to dicamba from use on DT-soybean could potentially 

result in effects to the species. Some listed species could be removed from concern for effects 

based on exclusions that currently exist and are documented. Exclusions that have been employed 

include change in species listing status, not present due to extirpation195, habitat not in proximity to 

agriculture, product properties (diet and feeding exclusions)196, and species not in proximity to 

agriculture for other reasons.

The proximity analysis at the sub-county level as described in Section IV.D.3 and species-specific 

refinements as described in Section IV.D.4 have been utilized in conjunction with the county-level 

identification of co-occurrences to evaluate potential effects to threatened and endangered species as 

discussed in the EPA Overview Document.197 T-REX was utilized for birds and mammals to 

calculate species- and diet-specific risk quotients. For amphibians and other relevant species, THERPS was utilized to calculate species- and diet-specific risk quotients for amphibians and reptiles 

with similar methods to those used in the assessments of the California red-legged frog. Diet 

information was utilized for individual species of birds, reptiles, and mammals to determine if actual 

diet considerations can justify removing a species from concern.

 

194 The FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act) Endangered Species Task Force (FESTF) Information 

Management System 2.7 (IMS) (referred to as the “FESTF IMS”) was developed in order to meet the legal obligations of its 

member companies to submit data required by EPA/OPP under FIFRA (as described in Pesticide Registration Notice 2000-2) 

in support of the members’ registration and re-registration actions. The purpose of the IMS is to meet the data requirements in a 

manner that significantly improves the consistency, quality, availability and use of existing information on threatened and 

endangered species and pesticide use. http://www.festf.org/visitors/default.asp. 

195 An extirpated species is defined as “a species no longer surviving in regions that were once part of its range” 

(http://www.fws.gov/midwest/endangered/glossary/index.html).

196 This type of exclusion is based on a quantitative analysis of dicamba properties beyond the screening level analysis in the EFED 

Science Chapter. Specifically, this analysis involves assessing use of measured foliar residues and foliar decline rates following 

dicamba applications, adjusted to reflect the use pattern for DT-soybeans. The size, diet, and food consumption of the animal 

species are also considered (See Section F.4.4.3 and Section F.4.4.6).

197 Overview Document (USEPA, 2004) p. 69 and p. 67, respectively.
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F.4.4.3. Sub-County Animal Species Observations versus Land Use Proximity Analysis

The analysis of proximity of relevant land use to sub-county locations of threatened or endangered 

animal species identified in the county-level analysis (Frank and Kemman, 2013a) is summarized in 

the sections that follow.

F.4.4.3.1. Land Use Information

For the contiguous U.S., land cover data considered in this analysis were obtained from the National 

Land Cover Dataset (minimum mapping unit: 30-meters)198. Data for the NLCD 2006 dataset were 

collected from 2001 and 2006 and represent the best comprehensive collection of national land use 

and land cover information for the U.S (NLCD, 2011). The land cover classes of pasture/hay (Class 

81) and cultivated crops (Class 82) were considered “relevant land use” for this analysis (or, for 

California, counties where herbicide applications on soybeans have been reported), since land 

designated as cultivated crops could potentially be used for DT-soybean production, and some 

pasture/hay fields could be converted to cultivated cropland. 

F.4.4.3.2. Species Locations

FESTF Multi- Jurisdictional Database (MJD)

Threatened and endangered animal species location data at a sub-county level were obtained from 

the FIFRA Endangered Species Task Force Multi-Jurisdictional Database (FESTF MJD; 

NatureServe 2012). The FESTF MJD consists of a “licensed dataset” drawn from NatureServe’s 

Multi-Jurisdictional Database (MJD) licensed to FESTF.199 The MJD species observation records 

included additional data fields, such as date of last observation and observation notes; this 

information was evaluated and utilized when relevant to the proximity assessment.

The MJD location data were provided as polygons (areas representing where a listed species was 

observed; referred to as a “species observation”). The spatial dataset was provided in a format 

suitable for analysis and display using Geographic Information System (GIS) software.

For the purposes of this analysis, species observations were considered “historic” if the “last 

observed date” for the observation (as reported by NatureServe in the FESTF MJD 2012 dataset) 

was prior to 1977 200 or if the observation was noted to be “Historical” or “Extirpated” in the 

FESTF MJD 2012 dataset licensed from NatureServe.

 

198 National Land Cover Database 2006 (NLCD 2006). URL: http://www.mrlc.gov/nlcd2006.php

For Hawaii, nearest distance to land use based on the NLCD 2001 dataset was considered.

199 Under the terms of the FESTF license with NatureServe, the sub-county threatened and endangered species location data are 

confidential information available only to FESTF, FESTF member companies, (including FESTF “Level II” companies), and 

the U.S. EPA’s Office of Pesticide Programs staff reviewing FESTF member-company registrations. Information based on 

the sub-county species location data may be shared with cooperating federal and state agencies for regulatory decision-making 

related to endangered species assessments for Monsanto products.

200 A time period for observations beginning in 1977 is considered a conservative time period for this analysis.
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F.4.4.3.3. Proximity Analysis Process

Proximity distances from each species observation (polygon) in the FESTF MJD 2012 dataset to 

NLCD 2006 Class 81 (Pasture/Hay) and Class 82 (Cultivated Crops) land area were available, and 

were used to evaluate potential proximity to land suitable for soybean production. The FIFRA 

Endangered Species Task Force used the MJD 2012 dataset to prepare a database entitled “FESTF 

MJD 2012/NLCD 2006 Species Occurrence/Land Cover Proximity Database – Classes 81 and 82”, 

and Classes 81 and 82 were included in this database. From this database, the nearest distance of a

species observation to relevant land use in a soybean production county was extracted for each 

species/county co-occurrence evaluated in Frank and Kemman (2013a).

The distance evaluated for potential proximity of each species observation to relevant land use for 

soybean production was determined based on each individual species home range, the area over 

which an animal normally travels and searches for food. Therefore, to remove a species from 

concern based on proximity, the home range for the individual species was determined as the 

minimum separation distance from the edge of the dicamba application area and the species 

observation.

Where relevant, land classified as soybean fields, based on 4 years of USDA Cropland Data Layer 

(CDL) data (2008 through 2011) (USDA2008, 2009,2010, 2011) was also considered in evaluating 

the proximity of a species observation to soybean production.

The California Pesticide Using Reporting database was also utilized to identify Public Land Survey 

Sections in the five California counties considered to have soybean production where pesticide 

applications had been made to soybeans, and hence were sections where soybeans have been grown. 

Pesticide Use Reports for the years 2001–2010 were used for this determination.

F.4.4.4. Species-specific Risk Quotient Calculations

Consistent with EPA’s Overview Document, species-specific dietary exposure was assessed 

considering animal body weight and diet (Schuler et al., 2013a) for birds and mammals of certain 

sizes, where risk quotients exceeded the level of concern after the initial refinements described 

above. A similar assessment was conducted for amphibians and reptiles because birds serve as the 

surrogate for terrestrial phase amphibians and reptiles. Biological information was gathered from a 

number of sources, including U.S. Fish and Wildlife Service (USFWS) species recovery plans, 

primary literature, and other technical sources (e.g. NatureServe201).

F.4.4.4.1. Mammals

In the county-level endangered species analysis, 54 threatened or endangered mammalian species 

were identified as potentially being present in or adjacent to a county with soybean production 

(Frank and Kemman, 2013). Of the original 54 species, 12 species were removed from 

 

201 NatureServe is a non-profit conservation organization that collects detailed local information on plants, animals, and ecosystems. 

NatureServe has a public website available at http://www.natureserve.org .
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consideration based on Habitat determinations and 7 species were deemed Not of Concern202 across 

all the counties evaluated (Frank and Kemman, 2013a).

The remaining 35 species of mammals were examined for the potential for chronic effects based on 

proximity to land relevant for soybean production and biological characteristics (i.e., dietary 

preferences and body size). The analysis progressed in a step-wise fashion:

 The proximity of each species observation to relevant land use for soybean production was 

compared to species home range information. Of the 35 species evaluated in this refined 

analysis, 12 species were excluded from concern due to lack of proximity to land relevant for 

soybean production.203

 The 23 remaining species received Product Property determinations (Diet Exclusions)204, 

since based on body size and diet, the RQs were less than LOC considering chronic 

exposure to upper bound residues.

 All calculations were based on the assumption that animals eat 100% of their diet at the 

upper bound residue levels. This is an extremely conservative assumption for a chronic

exposure scenario. Based on the EPA Overview Document for Endangered and Threatened 

Species Effects Determinations (US EPA 2004), the use of the mean residue value is an 

appropriate refinement for chronic exposures. When consumption of food containing the 

mean residue value is assumed, the dose-based chronic risk quotients are well below the 

LOC of 1 (Table F-60) for all diet types and body sizes, indicating that threatened or 

endangered wild mammals can be excluded from concern and, therefore, would not be 

affected. 205

 The Diet Exclusion was also applicable to the species assigned Proximity or Not of Concern 

determinations, resulting in a total of 35 mammalian species where a Diet Exclusion was 

applicable.

In summary, it can be concluded that no effects to mammalian species will result from the use of 

dicamba in DT-soybeans.

 

202 “Not of Concern” Determination: Species co-occurrences that are not of concern. Physical or regulatory factors provide clear evidence 

that a species is not of concern in a particular county. Examples include delisted species, no current presence, and historical or 

extirpated species. 

203 For all county co-occurrences that did not have applicable Not of Concern determinations.

204 This determination type identifies a particular species or taxon as not at risk based on the properties of the product (dicamba 

applied to DT-soybeans) when certain biological factors such as size (e.g. >1 kg) and diet (e.g., carnivorous, frugivorous, etc.) are 

considered.

205 Considering the rapid rate of dicamba foliar residue dissipation, even chronic RQs calculated for small mammals with the refined 

maximum measured residues only exceed the LOC for up to 2 days, not a sufficient duration to be considered a chronic 

exposure
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F.4.4.4.2. Birds

In the county-level endangered species analysis, 52 threatened or endangered avian species were 

identified as potentially being present in or adjacent to a county with soybean production (Frank and 

Kemman 2013a).

 Of the original 52 species, 12 species were removed from consideration based on Habitat 

determinations (Frank and Kemman 2013a).

 The proximity of each species observation to relevant land use for soybean production was 

compared to species home range information. Of the 40 species evaluated in the refined 

analysis, 7 were removed from concern due to a lack of proximity to land relevant for 

soybean production.206

 Of the remaining species evaluated in this refined analysis, 20 were assigned Product 

Property determinations (Diet Exclusion) because their T-REX acute RQs were less than the 

LOC based on characteristics of diet and body weight or their diets did not include items 

considered in the T-REX model (e.g., aquatic animals).207

 Using measured upper-bound dicamba residue values, RQ values exceeded the acute LOC 

of 0.1 only for small and medium-sized birds that consume grasses, broadleaf plants, or 

arthropods, and large birds consuming short grass and broadleaf plants (Table F-61).

 Dose-based RQs calculated for 13 species using the acute LD50 value exceeded the acute 

LOC of 0.1 for the dose-based upper bound residues indicating that further refinement 

should be considered (described below).

 Based on the refinements, the remaining 13 species were assigned Product Property 

determinations (Feeding Exclusion)208 because the upper bound EECs calculated for these 

species were lower than dose-based NOELs calculated from acute dietary exposure studies.

 The Diet and Feeding Exclusions were also applicable to the species assigned Proximity or 

Not of Concern determinations, resulting in totals of 21 species where a Diet Exclusion was 

applicable, and 19 species where a Feeding Exclusion was applicable.

 

206 For all county co-occurrences that did not have applicable Not of Concern determinations.

207 Diet items not included in T-REX were aquatic animals and small- to medium-sized mammals as prey. Exposure to dicamba 

residues from the consumption of aquatic animals was not considered to be of concern due to low surface water concentrations 

(Wright et al., 2013) and a low bioconcentration factor (BCF). Consumption of small- to medium-sized wild mammals by large 

carnivorous mammals (i.e. 1 kg or larger) is not a concern because dicamba does not bioaccumulate in mammalian tissues (U.S. 

EPA, 2005) and residues from food items that a prey might have consumed would not result in RQs exceeding the LOC for 

species of 1 kg or larger.

208 This determination type identifies a particular species as not at risk based on the properties of the product (dicamba applied to 

DT-soybeans) when certain biological factors such as size (e.g. >1 kg) and diet (e.g., carnivorous, frugivorous, etc.) are 

considered.
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Moreover, this analysis is conservative because it is likely that the birds would not be in soybean 

fields actively foraging, but rather foraging in the adjacent habitats (e.g., tree canopy) outside of the 

fields. Threatened and endangered species are “strongly associated” with their specific habitat type 

and, therefore, it is improbable that 100% of the bird’s diet would consist of dietary items exposed 

in the field. Additionally, EPA’s default approach to assessing acute risk is based on a single oral 

gavage dose (i.e., the entire dose is delivered to the animal at one time, typically after being dissolved 

in corn oil). In reality, of course, any pesticide exposure will not occur in this manner – but rather 

through dietary consumption of dicamba-exposed prey or food items. As a result, the gavage route 

of administration overestimates the exposure expected to occur in nature, and methods resulting in a 

dose-delivery over time (e.g., dietary exposure) are more environmentally relevant. Therefore, the 

use of the acute oral toxicity test (i.e., oral gavage) to predict risk of dicamba to birds in this case 

should be considered to be a screening-level approach that is expected to overestimate actual risk.

An acceptable refinement to the screening level risk assessment, based on guidance in the US EPA

Overview Document on Ecological Risk Assessment Process for Endangered and Threatened 

Species Effects Determinations, is to determine the acute risk to birds from consuming dicamba 

exposed prey or food items from an estimate of the dose-based effect levels calculated from acute 

dietary toxicity studies.

 From short-term dietary toxicity tests using bobwhite quail chicks and mallard ducklings 

exposed to dicamba diglycolamine salt for 5 d, the dose-based NOEL values were 

determined (Grimes, 1986a; Grimes, 1986b). The use of the NOEL value in place of the 

LC50 for an acute assessment provides additional conservatism when assessing for potential 

effects on endangered species. 

 For birds, the dose-based EECs were calculated based on the refined foliar residue and 

DT50values and assuming 100% of the diet was obtained within the field. The short/tall 

grass residue values were refined based on the maximum measured Day 0 residues from 59 

dicamba specific field trials in pasture grasses. 

 From this analysis, the dose-based EECs for small passerine birds consuming a diet exposed 

in the field are below the dose-based NOEL values (Schuler et al., 2013a), 

 Conservatively assuming that the avian species evaluated are passerine species (highest 

metabolic/ingestion rates, U.S. EPA, 1993), they cannot ingest enough food to achieve 

doses that would exceed the unbounded NOEL (highest dose tested). 

 In addition, compared to the larger birds used in the gavage study (e.g., 178 g and 1,580 g for 

the bobwhite quail and mallard duck, respectively), the sizes of birds used in the dietary 

studies (e.g., 37 g and 264 g for the bobwhite quail and mallard duck, respectively) are much 

more relevant to birds considered in this analysis; thereby reducing uncertainty in the toxicity 

value adjustment.

In summary, it can be concluded that no effects to birds will result from the use of dicamba in DTsoybeans. 
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F.4.4.4.3. Amphibians and Reptiles

In the county-level endangered species analysis, 13 terrestrial-phase amphibian species and 20 reptile 

species were identified as potentially being in or adjacent to a county with soybean production 

(Frank and Kemman, 2013a). Of these species, 3 amphibian and 5 reptile species were removed 

from consideration based on Habitat determinations. Additionally, 2 reptile species were deemed 

Not of Concern across all counties evaluated (Frank and Kemman, 2013a). 

The remaining 10 amphibian and 13 reptile species were evaluated based on their proximity to 

agriculture and species-specific refinements (Schuler et al, 2013a). 

 The proximity of each species observation to relevant land use for soybean production was 

compared to species home range information. Five amphibian and three reptile species were 

removed from concern due to a lack of proximity to land relevant for soybean production.209

 The remaining species (5 amphibian species and 10 reptile species) all received Product 

Property determinations (Diet Exclusion) because their T-HERPS RQ values were less than 

the LOC based on characteristics of diet and body weight.

 The Diet Exclusion was also applicable to the species assigned Proximity or Not of Concern 

determinations, resulting in totals of 10 amphibian and 13 reptile species where a Diet 

Exclusion was applicable.

In summary, it can be concluded that no effects to terrestrial-phase amphibians or terrestrial reptiles 

will result from the use of dicamba in DT-soybeans.

F.4.4.5. Indirect Effects on Threatened and Endangered Species of Other Taxa Resulting 

from Direct Effects on Plant Species.

To assess the potential for indirect effects on threatened and endangered species, the EPA evaluates 

the risk of direct effects on non-endangered species from relevant taxonomic groups to make 

inferences concerning the potential for indirect effects upon threatened or endangered species that 

rely on non-endangered species in that category for critical resources (USEPA, 2004). The RQ 

values used to assess the potential for indirect effects from dicamba applications to DT-soybean 

indicate that indirect effects to other taxa resulting from effects on monocot plant species from 

application of dicamba at rates up to 1.0 lb a.e./A would not occur. Further, indirect effects to 

other taxa as a result of effects on dicot plant species from a combination of sheet runoff and spray 

drift to soil would also not occur (Wright et al., 2013). In addition, utilizing a refined exposure 

assessment, indirect effects to other taxa resulting from effects on dicot plant species exposed via a 

combination of channelized runoff and spray drift to soil would not occur (Wright et al., 2013). 

When RQ values are calculated for all six of the dicot species tested in the vegetative vigor study, 

RQs exceed the LOC for only two of the six species indicating that habitat and food sources from 

dicot plants will be present adjacent to areas treated with dicamba (Wright et al., 2013). 

 

209 For all county co-occurrences that did not have applicable Not of Concern determinations.
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Furthermore, field studies demonstrate that even very sensitive plants at the edge of a field sprayed 

with dicamba are not affected to the extent that impacts on habitat would result. Additionally, 

effects from drift can be further minimized through the use of application requirements such as drift 

reducing technologies (e.g., low drift spray nozzles, boom height, deposition aides). A separate 

report (Schuler et al., 2013b) assesses the potential for indirect effects on threatened and endangered 

species.

F.4.4.6. Conclusions

In the EFED ecological risk assessment conducted for dicamba reregistration (USEPA, 2005), using 

a screening level assessment, EPA scientists concluded that a “no effect” determination can be made 

for all dicamba uses for listed fish, and aquatic invertebrates. The potential for adverse effects to 

listed birds and mammals could not be excluded based on the EPA screening level assessment, the 

initial phase of analysis. Recognizing that screening level analysis is only the first step in evaluating 

impacts on threatened and endangered species, the EFED Science Chapter (USEPA, 2005) indicates 

that “additional information on the biology of listed species, the locations of these species, and the 

locations of the use sites...could be considered along with available information on the fate and 

transport properties of the pesticide to determine the extent to which screening assumptions 

regarding an action area apply to a particular listed organism.”

The above discussion summarizes the conclusions of three other reports (Wright et al., 2013; Frank 

and Kemman, 2013a; Schuler et al., 2013a) that utilize some of the refinements described by EPA in 

the previous paragraph to evaluate the potential for adverse effects to listed birds, mammals, 

amphibians, reptiles and terrestrial invertebrates. When the properties of dicamba and speciesspecific information are taken into account, these reports demonstrate that listed birds, mammals, 

amphibians, reptiles, and terrestrial invertebrates would not be affected by dicamba use in DTsoybean. 

F.4.5. Impact on Threatened or Endangered Plant Species from Dicamba Use on DGT 

Cotton

F.4.5.1. Endangered Species Exposure and Effects Analysis

F.4.5.1.1. Screening-Level Analysis

An initial analysis was conducted of the potential for exposure and effects to all taxa (including 

plants) from dicamba use in cotton with the DT trait (Honegger et al., 2013) using the EPA 

deterministic risk quotient approach (USEPA, 2004). The analysis in Honegger et al. was based on 

a use pattern more conservative than that reflected in the proposed label whose approval is pending 

at EPA. The use pattern for dicamba utilized in this analysis was a pre-emergence application at a 

rate of 1.0 lb dicamba acid equivalents per acre (a.e./A) followed by two post-emergence 

applications each at a rate of 0.5 lb a.e./A with a 6-day interval between the pre-emergence 

application and the first post-emergence application, and a 6-day interval between the two postemergence applications, with all applications being made using ground application equipment. The 

6-day application intervals utilized in this analysis are shorter and more conservative than the 7-day 

interval specified on the proposed dicamba label for use in cotton with the DT trait, but were used 

for consistency with the analysis for DT-soybeans. 
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For aquatic plants, initial exposure estimates using the above described use pattern were based on 

the standard EPA exposure models GENEEC 2.0 and PRZM (3.12.2)/EXAMS (2.98.04.6) and 

toxicity effects endpoints taken from the EPA Environmental Fate and Effects Division (EFED) 

Science Chapter for the Reregistration Eligibility Decision for dicamba (USEPA, 2005). 

For terrestrial plants, initial exposure estimates using the above described use pattern were based on 

the standard EPA exposure model TerrPlant 1.2.2 and default assumptions; toxicity effects 

endpoints were taken from EPA guideline studies conducted by BASF under an EPA data call-in 

(Porch et al., 2009a and 2009b). 

The conclusion from this initial analysis (Honegger et al., 2013), based on risk quotients (RQs) being 

less than the EPA Levels of Concern (LOCs), is that dicamba use on cotton with the DT trait would 

not affect threatened and endangered plant species in the following taxa: 

 Aquatic vascular plants

 Monocotyledonous terrestrial plant species (monocots) 

Although the RQ for listed aquatic non-vascular plants exceeded the LOC, additional analysis was 

not conducted because there are no federally listed non-vascular aquatic plants. The RQ for nonlisted aquatic non-vascular plants was less than the LOC, indicating that other taxa of threatened and 

endangered species would not incur indirect effects as a result of effects on non-listed non-vascular 

aquatic plants.

These conclusions for aquatic plants are consistent with the risk conclusions presented in the EFED 

science chapter for dicamba reregistration (USEPA, 2005 and 2009). 

The conclusion for monocots is supported by more recent nontarget plant studies with a typical 

dicamba end use product containing the diglycolamine salt of dicamba. These studies were required 

by EPA during the reregistration process to assess the phytotoxicity of an end-use product 

containing the diglycolamine salt. Only endpoints for dicamba acid were available for consideration 

in the EFED science chapter (USEPA, 2005 and 2009) for which it was concluded that the RQ 

exceeded the LOC. Toxicity endpoints for the diglycolamine salt were not available at that time to 

calculate an RQ for comparison with the LOC (Porch et al., 2009a and 2009b). Using the noobserved-effect endpoints from these 2009 studies and the EPA model TerrPlant to calculate 

exposure and risk quotients, the RQs for monocots were below the LOC (Honegger et al., 2013), 

and thus result in a conclusion that monocots would not be affected by use of the diglycolamine salt 

of dicamba on cotton with the DT trait. The levels of concern considered by EPA for threatened 

and endangered (listed) species risk assessments are given in Table F-62.
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Table F-62. EPA Levels of Concern for Threatened and Endangered Plant Species 

(USEPA, 2004)

Risk Presumption Calculation for Risk Quotient Level of Concern

Terrestrial and Semi-Aquatic Plants

 Acute Risk EEC/EC05 or NOAEC 1.0

Aquatic Plants

 Acute Risk EEC/EC05 or NOAEC 1.0

For threatened and endangered terrestrial plant species in classes other than monocotyledons, 

further analysis is required.

F.4.5.1.2. Refined Analysis for Listed Plants Considering County-Level Information

Consistent with EPA guidance found in the Overview Document (USEPA, 2004), if screening-level 

assessments do not result in a “no effect” determination, EPA does not then conclude that an 

herbicide “may affect” threatened and endangered species; rather, more refined assessments must be 

conducted to ascertain if any effects are expected to occur. Based on this guidance, a more detailed 

evaluation of the locations of threatened and endangered plant species relative to potential areas of 

cotton production, and, therefore, potential dicamba use was undertaken. 

First, the co-occurrence of threatened and endangered plant species and the production of cotton 

was evaluated at the county level. Listing status , species habitat, species observation history in the 

county, and proximity data to cotton production at the county level were evaluated to determine: (1) 

which species in which counties can be excluded from further evaluation; and (2) which require 

further evaluation. This process is referred to as the “county-level analysis” (Frank and Kemman 

2013) and is discussed in more detail in Section IV.E.2. 

F.4.5.2. County Level Analysis: Co-occurrence of Listed Plant Species in Crop Production 

Areas

The procedures used in the county-level analysis to identify counties containing threatened or

endangered species that require further evaluation are described in detail in Frank and Kemman 

(2013b). The U.S. counties where cotton production was reported were identified using available 

data from the U.S. Census of Agriculture. Census data from 1997, 2002 and 2007 were utilized to 

identify these counties. Counties without cotton production, but adjacent to counties with cotton 

production were also identified. In total, there were 1,198 counties considered in this analysis (733 

cotton counties, 465 adjacent counties). 

In the identified counties, available county-level presence information for threatened or endangered 

plant species was evaluated, using county-level location information compiled by the FIFRA 

Endangered Species Task Force (FESTF) in the FESTF Information Management System (IMS). 

Of the 1,198 counties initially considered, there were 355 counties in 18 states with reported cotton 

farms (or adjacent to counties with reported cotton farms) and reported presence of listed plant 

species. These counties represented 162 listed plant species. There were 1,697 species-county cooccurrence records considered across all plant taxa (see Table F-63). 
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In these counties, each species was evaluated with respect to the current listing status, county-level 

locations, species habitat requirements, and plant classification in order to determine whether 

exposure to dicamba from use on cotton with the DT trait could potentially result in effects to the 

species. Some listed species could be removed from concern for effects based on exclusions that 

currently exist and are documented. Exclusions that have been employed include change in species 

listing status, not present due to extirpation, historic observations (no observations since 1977 or 

earlier), habitat not in proximity to agriculture, product properties related to plant taxa selectivity, or 

species not in proximity to agriculture for other reasons. Table F-63, as reported in Frank and 

Kemman (2013), provides a summary of the results of the county-level analysis after exclusions have 

been considered. Species assigned a Not of Concern determination have information from a U.S. 

Fish & Wildlife Service (USFWS) or NatureServe source, or a state or local expert to indicate that 

the species is not present in the county or is not in proximity to cotton production.

Table F-63. Summary of Species Determinations for this Analysis (from Frank and 

Kemman, 2013) 

Determination Type Number of 

States

Number of 

Counties

Number of 

Species

Number of 

Co-Occurrences

Not of Concern 18 298 131 512a

Product-Property 14 151 39 207

Habitat 15 153 130 329

Species Management Practiceb 2 2 2 2

Requires Further Analysis 18 357 162 647

Total 1,697

Total distinctc 22 605 329

a Of the 512 co-occurrences with a Not of Concern determination, 507 of the determinations were supported by information 

from the U.S. Fish & Wildlife Service county list or a regional office expert; 5 determinations were supported by information

from NatureServe or a state or local species expert.

b Species is present on public or private land protected by conservation plans or agreements.

c More than one determination type may be assigned to different county-level co-occurrences of the same species. Therefore, the 

total number of species (or counties) for all determination types is more than the total number of distinct species (or counties). 

After considering co-occurrences for which exclusions apply, county-species co-occurrences remain 

in 18 states, in a total of 357 counties, and for 162 species, which require further analysis. As 

described in the EPA Overview Document (USEPA, 2004), the next step in the analysis is to 

consider these co-occurrences at the sub-county level evaluating the proximity of the species 

observation and the land areas that have the potential to be used for cotton production. 

F.4.5.3. Sub-County Plant Species Observations Versus Land Use Proximity Analysis

The following discussion describes the analysis of proximity of relevant land use to sub-county 

locations of threatened or endangered plant species that have been identified as “requiring further 

analysis” in the county-level analysis (Frank and Kemman, 2013b). A summary of the spatial 

information used and the proximity analysis is provided in the sections that follow.
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F.4.5.3.1. Land Use Information

Land cover data considered in this analysis were obtained from the National Land Cover Dataset 

(NLCD 2006) with a spatial resolution of 30-meters (NLCD, 2011). Data for the 2006 NLCD were 

collected from 2001-2006 and represent the best comprehensive collection of national land use and 

land cover information for the U.S (NLCD, 2011). “Relevant land use” considered were areas 

classified as Pasture/Hay (Class 81) or Cultivated Crops (Class 82) by the National Land Cover 

Database (NLCD) 2006 (NLCD 2011; Fry et al., 2011), in counties with reported cotton farms. 

This conservative approach considered that land designated as cultivated crops could potentially be 

used for production of cotton with the DT trait, and some pasture/hay fields could be converted to 

cultivated cropland. 

For California, additional information regarding cotton production areas was obtained from the 

California Pesticide Use Reporting (PUR) database (California DPR 2013). Records from the PUR 

database were used to identify the Public Land Survey System (PLSS) sections where applications of 

pesticides to cotton were reported, as required by California regulations. As reported in Frank and 

Kemman (2013b), there were 13 California counties defined as having cotton production, based on 

Census of Agriculture information. For these counties, the PLSS sections with reported applications 

of pesticides to cotton for the California PUR reporting years of 2000 through 2011 were identified.

In some situations, available satellite imagery was used to verify the proximity of species 

observations to agricultural lands (a verification of the NLCD 2006 land use classification). The 

source of satellite imagery was either the dynamic map services provided by ESRI (including the 

“ESRI_Imagery_World_2D” map service), or the Bing map service. 

F.4.5.3.2. Species Locations

FESTF Multi- Jurisdictional Database (MJD)

Threatened and endangered plant species location data at a sub-county level were obtained from the 

FIFRA Endangered Species Task Force Multi-Jurisdictional Database (FESTF MJD; NatureServe, 

2012). The FESTF MJD consists of a “licensed dataset” drawn from NatureServe’s MultiJurisdictional Database (MJD) licensed to FESTF. The MJD species observation records included 

additional data fields, such as date of last observation and observation notes; this information was 

evaluated and utilized when relevant to the proximity assessment.

The MJD location data were provided as polygons (areas representing where a listed plant species 

was observed; referred to as a “species observation”). The spatial dataset was provided in a format 

suitable for analysis and display using Geographic Information System (GIS) software. Polygons for 

listed dicots are as small as 5 square meters and as large as 377 square kilometers.

For the purposes of this analysis, species observations were considered “historic” if the “last 

observed date” for the observation (as reported by NatureServe in the MJD 2012 dataset) was prior 

to 1977. Additional observation-specific data available in the MJD 2012 dataset (e.g., field notes) 

were examined to identify observations that are noted to be “historic” or “extirpated.” In some 

cases, species with observations later than 1976 were flagged as “extirpated.” In situations of 

historic or extirpated species observations, no further analysis was conducted. 
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F.4.5.3.3. State-Specific Location Data

Spatial data depicting the locations of five plant species in selected Texas counties were obtained 

from the Texas Natural Diversity Database (TXNDD). This species location information was not 

included in the FESTF MJD 2012 datatset. Proximity between the TXNDD species observations 

and relevant land use was measured using tools available in the GIS software.

The Maryland state heritage program did not contribute data to the NatureServe MJD. Sub-county 

location information for species for Maryland was not available for this analysis. Additional research 

will be conducted to determine whether the Maryland plant species are near agriculture. 

F.4.5.3.4. Proximity Database

For listed plant species observations available in the FESTF MJD 2012 dataset, proximity distances 

from each species observation (polygon) to NLCD 2006 Class 81 (Pasture/Hay) and Class 82 

(Cultivated Crops) land area (or, for California, to survey sections in counties with reported pesticide 

applications to cotton; see further description below) were available, and were used to evaluate 

potential proximity to relevant land used for cotton production. 

The FIFRA Endangered Species Task Force used the MJD 2012 dataset to prepare a database 

entitled “FESTF MJD 2012/NLCD 2006 Species Occurrence/Land Cover Proximity Database –

Classes 81 and 82,” and Classes 81 and 82 were included in this database (FESTF NatureServe 2012; 

Konkel and Frank 2012). From this database, the nearest distance of a species observation to 

relevant land use in a county with cotton farms was extracted for each species/county co-occurrence 

evaluated in Frank and Kemman (2013).

F.4.5.3.5. Proximity Analysis Process

It was concluded in the county-level evaluation for cotton with the DT trait (Frank and Kemman, 

2013b) that certain listed plant species could not be excluded from concern (at the county level) due 

to potential exposure to dicamba during ground applications of dicamba to cotton with the DT trait. 

Therefore, it was necessary to assess the potential proximity of those listed plant species (those 

identified as “requiring further analysis” in the county-level evaluation) to agricultural land that could 

be used for cotton production. Proximity was also assessed for species assigned habitat 

determinations in Frank and Kemman (2013b).

The basic steps of the proximity analysis (as described in Carr and Orr, 2013a) were as follows:

1. Identify the plant species-county co-occurrences that were assigned a “requires 

further analysis” determination in the county-level evaluation (Frank and Kemman 

2013b).

2. Obtain comprehensive spatial data regarding sub-county plant species locations, 

where available, for the states and counties identified in Step 1. Sub-county location 

information was not available for all species-county co-occurrences evaluated.

3. Identify land use suitable for cotton production, in counties with cotton production. 

Cotton production counties were defined in the same manner as was considered in 

the county-level analysis (Frank and Kemman 2013b). This definition was based on 
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three consecutive Censuses of Agriculture (for the years 1997, 2002, and 2007). If a 

cotton farm (or farms) was reported in a county for any of the three Censuses, then 

it was assumed that cotton production occurred in that county. 

4. Using the FESTF Proximity Database (described in Section IV.E.3.d) in 

combination with GIS software, identify species observations that have overlap with 

or are within 450 feet of land use relevant for cotton production (i.e., have 

“potential proximity to relevant land use”). 

The distance of 450 feet is greater than the distance from the edge of the dicamba 

application area to a point at which an effect on soybean plant height is no longer 

observed, when the proposed mandatory FIFRA application requirements for the 

dicamba diglycolamine salt are employed (Orr, et al., 2012; Honegger, 2012b). 

Utilizing the EPA screening assessment approach as described in the EPA Overview 

Document (USEPA, 2004), soybeans have been demonstrated to be the most 

sensitive species to the effects of dicamba (Porch et al., 2009a, 2009b), and plant 

height was the most sensitive endpoint in the vegetative vigor study (Honegger et al., 

2013). 

5. As indicated above, not all counties have sub-county species location information. 

In these cases, potential proximity was assumed , unless additional information was 

available to determine that the species was not within 450 feet of relevant land use. 

Thses records are referred to as “county-level record” in the tables summarizing the 

potential proximity results.

Where applicable, satellite imagery was used to assign a “no proximity” conclusion, even though the 

NLCD proximity distance was less than 450 feet. Generally, if the imagery indicated that the species 

location was not within 450 feet of tillable agricultural land, due either to mis-classification within 

the NLCD or due to land use change since the NLCD data were collected, then it was concluded 

that the species could be excluded from concern for effects of dicamba used on cotton containing 

the DT trait. Examples of non-agricultural land use that imagery could identify are developed 

residential areas, a grassy roadside, utility rights-of-way, shorelines, water bodies, and forest clear-cut 

areas.

Species and counties were identified as requiring further analysis at the conclusion of the countylevel evaluation (Frank and Kemman 2013b). In this analysis, there were 162 distinct plant species 

in 357 counties in 18 states evaluated. Where species observations were available, there were 4,239

species observations evaluated for potential proximity to relevant land use for cotton production. 

F.4.5.3.6. Conclusions of the Proximity Analysis

Table F-64 and Table F-65 present the results of the proximity analysis for the cotton production 

states included in this appendix, summarized in Table F-64 by U.S. FWS region and in Table F-65 

by state. 
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Table F-64. Results of Proximity Analysis Presented (by Region)

US 

FWSRegion

Requires Further Analysis

Number of:

With Potential Proximity to Relevant Land Use; 

Number of:

Species/ 

County 

Records a

States Counties

Plant 

Species

Species 

Obs b

Countylevel 

Recordc

States Counties

Plant 

Species

Species 

Obs b

Countylevel 

Recordc

Southwest 

(Region 2)

58e 3 40 28 333 4 3 16 14 38 4

Midwest 

(Region 3)

27 1 19 6 171 2 1 6 6 31 2

Southeast(Reg

ion 4)

358 9 225 61 2,438 28 9 113 30 475 25

Northeast 

(Region 5)

19 2 19 7 33 2 2 11 4 5 2

MountainPrairie(Region 

6)

15 2 12 6 218 -- 1 4 1 125 --

Pacific 

Southwest 

(Region 8)

170 2 42 68 1,048 27 1 9 9 11 4

Totals 

(unique)d

648 18 357 162 4,239 63 16 159 58 685 37

a As reported in the county-level analysis (Frank and Kemman, 2013b). 

b Numbers represent species observation data available from the FESTF MJD dataset or from other Heritage Program sources. c 

Numbers represent species/county co-occurrences where sub-county location data was not available from the FESTF MJD 

2012 dataset.

d This total may not equal the sum of the regional values, since some species are present in more than one county, state, or region.

e In the Southwest Region, one additional co-occurrence was evaluated, based on information obtained from the Texas Natural 

Diversity Database. 
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Table F-65. Results of Proximity Analysis Presented (by State)

State

Requires Further Analysis

Number of:

With Potential Proximity to Relevant Land Use; 

Number of:

Species/

County 

Records a

Counties Plant 

Species

Species

Obs b

Countylevel 

Recordc

Counties Plant 

Species

Species

Obs b

Countylevel 

Recordc

Southwest (Region 2)

Arizona 20 12 10 109 2 3 3 1 2

New Mexico 6 5 4 73 1 3 3 9 1

Texas 32e 23 12 151 1 10 9 28 1

Midwest (Region 3)

Missouri 27 19 6 171 2 6 6 31 2

Southeast (Region 4)

Alabama 58 36 14 151 20 26 14 40 18

Arkansas 12 12 3 83 -- 3 1 27 --

Florida 64 19 32 767 2 5 3 5 1

Georgia 49 39 13 216 -- 16 7 42 --

Louisiana 6 6 3 10 1 1 1 -- 1

Mississippi 17 17 3 118 -- 9 3 18 --

North Carolina 80 52 14 692 1 31 9 272 1

South Carolina 52 31 10 270 4 19 6 63 4

Tennessee 21 13 7 135 -- 3 4 9 --

Northeast (Region 5)

Maryland 2 2 2 -- 2 2 2 -- 2

Virginia 17 17 6 33 -- 9 3 5 --

Mountain-Prairie (Region 6)

Kansas 10 10 1 204 -- 4 1 125 --

Utah 5 2 5 14 -- -- -- -- --

Pacific Southwest (Region 8)

California 172 42 68 1,048 27 9 9 11 4

Totals 648 357 162 d 4,239 d 63 17 159 d 685 d 37

a As reported in the county-level analysis (Frank and Kemman, 2013b). 

b Numbers represent species observation data available from the FESTF MJD 2012 dataset or from other Heritage Program

sources. c Numbers represent species/county co-occurrences where sub-county location data was not available from the 

FESTF MJD 2012 dataset.

d This total may not equal the sum of the regional values, since some species or species observations are present in more than one 

region, state or county.

e In Texas, one additional co-occurrence was evaluated, based on information obtained from the Texas Natural Diversity Database.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 831 of 946

F.4.5.4. Sub-county Areas for Potential Use Limitation and Mitigation Measures

Monsanto defined potential areas around threatened or endangered plant species locations where 

label restrictions related to threatened and endangered species may be required. These areas have 

been defined to ensure species protection. The three components needed for implementation of 

potential use limitation areas are: 

4. definition of the sub-county areas that include threatened and endangered plant 

species locations, as well as additional area so that the listed species are protected 

from disturbance or collection by rare plant enthusiasts;

5. development of habitat descriptions for the listed plant species within these areas; 

and 

6. definition of label requirements that provide listed plant species protection from 

potential dicamba exposure.

F.4.5.4.1. Sub-county Descriptions of Potential Use Limitation Areas

For the observations of threatened or endangered plant species that overlap or are within 450 feet of 

relevant land uses, the next step of the analysis is to identify these species observations in such a way 

that appropriate label restrictions can be applied. Because the sub-county species location 

information is confidential under the terms of the NatureServe licensing agreement, the species 

locations cannot be disclosed to the public (see Footnote 43). Therefore, each of the state-level 

agencies or programs that provided sub-county species location data to NatureServe was contacted 

to determine whether it was acceptable for the sub-county species location information to be 

available to the public with only an additional 450 feet distance applied as a “resolution distance” 

around the area identified as the species location. In some cases, this distance was acceptable. In 

most cases, the state programs requested that a larger area be identified to provide an additional 

layer of conservatism regarding the location of the species.

Proximity analysis tools available in GIS software were used to add the additional area requested by 

the state heritage programs to the species observation area. These “buffered” observations were 

then further expanded so that potential use limitation boundaries could be described using 

surrounding surface features, such as roads, creeks, rivers, and railroads, and land survey boundaries 

(sections), where available. Maps depicting each listed plant species observation with proximity to 

relevant land use and the subsequently derived potential use limitation area are presented in the 

confidential attachment of Carr and Orr (2013b). 

F.4.5.4.2. Habitat Descriptions 

Habitat descriptions have been developed for each threatened or endangered plant species for which 

areas of potential use limitation have been proposed. These descriptions were developed from plant 

species information available from government and academic sources. Within the areas described 

for potential use limitation, mandatory label restrictions are only considered necessary when the 

habitat for the listed species is present. These habitat descriptions are included in the detailed report 

(Carr and Orr, 2013b).
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F.4.5.4.3. Label Restrictions

A proposed label has been submitted for the dicamba diglycolamine salt formulation for the new use 

on DGT cotton. This proposed label, which is currently pending before EPA, includes mandatory 

application requirements to minimize off-site movement. These requirements include 

implementation of a buffer when listed plant species are downwind from application areas. A 

further explanation of these measures to reduce off-site movement is presented in Honegger 

(2012b).

F.4.5.4.4. Overall Process for Sub-county Analysis

Polygons depicting threatened or endangered plant species locations that are within 450 feet of 

agricultural land where cotton could potentially be grown, based on Ag Census information, have 

been increased in size and geographically mapped to allow public presentation of areas where listed 

plant species may be present. In addition, while not making species names public, brief, clearlyworded habitat descriptions have been developed for each potential use limitation area to allow the 

applicator / grower to ascertain whether suitable habitat for the species is present in the area 

downwind from the planned application area. Because of the need to increase the size of the 

publicly identified area beyond the boundaries of the listed species location, it is proposed that only 

if the appropriate habitat is present would the buffer mandated by the proposed label apply. 

F.4.5.4.5. Web-Based System to Communicate Use Limitations 

To provide a convenient mechanism to present the locations of potential use limitation areas to 

growers/applicators, a web-based system similar to the system developed for glyphosate (www.PreServe.org) is under development for dicamba. This web site will guide growers and applicators 

through a simple step-wise process to determine whether their fields fall within potential use 

limitation areas – areas where threatened or endangered plant species and/or habitat for those 

species may be present. Where fields do fall within potential use limitation areas and appropriate 

habitat is present, the web-based system will reiterate to the growers the mandatory steps (as 

specified on the proposed label) that must be taken to reduce exposure to threatened and 

endangered plant species and avoid effects on survival, growth, and reproduction of these species. 

As an alternative to using the web-based program, growers/applicators will be able to call a hotline 

to obtain this information.

F.4.5.5. Conclusion

The above discussion provides a summary of the multi-step process that has been used to assess 

potential effects to threatened and endangered plant species from the use of dicamba on cotton 

containing the DT trait. The process used to evaluate the potential proximity of listed plant species 

observations to relevant land use in U.S. counties with cotton production is described in detail. 

Comprehensive sub-county species location data and national land cover data were utilized. 

In the 18 U.S. states where sub-county proximity was evaluated (listed in Table F-65), there are 58 

listed plant species in 17 states (159 counties) where species observations are within 450 feet of 

relevant land use for cotton production (in counties with reported cotton farms), using best available 

data for species locations and land use. The observations within 450 feet of relevant land use were 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 833 of 946

classified as having potential proximity to areas where dicamba could be used in production of DGT 

cotton. 

The 450-foot proximity evaluation is considered conservative because of the possibility that 

unidentified local factors may render use limitations unnecessary in areas that this analysis identifies 

as having 450-foot proximity determinations. 

In the EFED ecological risk assessment conducted for dicamba re-registration (USEPA, 2005), 

using a screening-level assessment, EPA scientists concluded that a “no effect” determination can be 

made for all dicamba uses for listed fish, aquatic invertebrates, and vascular aquatic plant species. 

The potential for adverse effects to listed birds and mammals, non-vascular aquatic plants and 

terrestrial and semi-aquatic plants could not be excluded based on the EPA screening-level 

assessment, the initial phase of analysis. However, since there are currently no listed non-vascular 

aquatic plants, and non-listed non-vascular aquatic plants have an RQ below the LOC, this taxon 

does not require further investigation at this time. Recognizing that screening-level analysis is only 

the first step in evaluating impacts on threatened and endangered species, the EFED Science 

Chapter (USEPA, 2005) indicates that “additional information on the biology of listed species, the 

locations of these species, and the locations of the use sites ... could be considered along with 

available information on the fate and transport properties of the pesticide to determine the extent to 

which screening assumptions regarding an action area apply to a particular listed organism.” 

When the properties of dicamba and species-specific information are taken into account, these 

reports demonstrate that monocotyledonous terrestrial and semi-aquatic plants outside the treated 

area also would not be affected (Honegger et al., 2013). The identification of species observations 

with potential proximity to land relevant for cotton production, and the definition of use limitation 

areas for such observations that are readily available to the grower/applicator, coupled with the 

proposed mandatory application requirements on the proposed label, which is currently before 

EPA, provide a mechanism to minimize exposure to dicamba so that threatened and endangered 

terrestrial plant species in taxa other than monocots are not affected by dicamba application to 

cotton containing the dicamba tolerance trait. 

Table F-66 summarizes the results of each step in this process. The analysis was initiated by 

considering all counties in the United States where cotton farms have been reported and in which 

threatened or endangered plant species have been observed. The presence of a single cotton farm 

in any one of three Censuses of Agriculture spanning a ten-year period resulted in inclusion of that 

county in the analysis. In addition, listed species from counties adjacent to cotton production 

counties were also included in the analysis. Exclusions for habitat protections, proximity analysis, 

and observation notes were used to identify areas and species where a potential for effects from 

exposure to dicamba could not be excluded. These areas were defined with precision to protect 

species and not reveal their exact location. By providing a mechanism to identify these areas to 

applicators and growers, required application practices on the proposed herbicide label can be used 

to avoid exposure so that these species would not be affected by dicamba use on DGT cotton.
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Table F-66. Numbers of counties, listed plant species, and observations involved in the 

analysis for cotton with the DT trait at major steps in the analysis

Analysis Category

Number of:

States Counties

Listed Plant 

Species

Species-County 

Co-occurrences

Species

Observationsa

Countylevel 

Presenceb

Cotton production 

counties & adjacent 

counties c

22 1,198 -- -- --

Cotton production 

counties & adjacent 

counties that have 

presence of listed 

plant species c

22 605 329 -- --

Species-county cooccurrences 

evaluated for 

potential proximity 

(450-ft) to relevant 

land use d

18 357 162 648e 4,239 a 50

Species observations 

with potential 

proximity to 

relevant land use f

17 159 58 199 685 a 37

a Numbers represent species observation data available from the FESTF MJD dataset or from other Heritage Program sources. 

b Numbers represent species/county co-occurrences where sub-county location data was not available from the FESTF MJD 2012 

dataset.

c

 As reported in Frank and Kemman (2013b). 

d These co-occurrences are the records assigned a “Requires Further Analysis” determination in Frank and Kemman (2013b). 

e This includes 647 co-occurrences records (as reported in Frank and Kemman, 2013) and 1 additional record, to

account for information received from the Texas heritage program, indicating presence of a species in an additional 

county not considered by Frank and Kemman (2013).

f These values exclude species observations that are Historic or Extirpated, or have a last observed date prior to 1977.

F.4.6. Impact on Threatened or Endangered Animal Species from Dicamba Use on DGT 

Cotton
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F.4.6.1. Endangered Species Exposure and Effects Analysis

F.4.6.1.1. Screening Level Analysis

An initial analysis was conducted (Honegger et al., 2013) of the potential for exposure and effects to 

all animal taxa from dicamba use in DGT cotton based on a use pattern more conservative than that 

pending for cotton at EPA using the EPA deterministic risk quotient approach (USEPA, 2004).210 

The use pattern for dicamba utilized in this analysis was a pre-emergence application at a rate of 1.0 

lb dicamba acid equivalents per acre (a.e/A) followed by two post-emergence applications each at a 

rate of 0.5 lb a.e./A with a 6-day interval between the pre-emergence application and the first postemergence application, and a 6-day interval between the two post-emergence applications211, with all 

applications being made using ground application equipment.212 The 6-day application interval 

utilized in this analysis is shorter than the minimum interval mandated under the proposed label (7 

days), and seven days is expected to be shorter than the interval actually used in practice, since a 

grower will typically allow weed regrowth to occur before making a new application – and that 

generally takes more than 7 days. Thus, the 6-day interval was assumed in an abundance of caution, 

to ensure a highly conservative exposure estimate, and to maintain consistency with the dicamba 

tolerant soy endangered species assessments.

Initial exposure estimates using the above described use pattern were based on standard EPA 

exposure models and default assumptions; toxicity effects endpoints were taken from the EPA 

Environmental Fate and Effects Division (EFED) Reregistration Chapter for Dicamba/Dicamba 

Salts (USEPA, 2005). The conclusion from this initial screening analysis, based on risk quotients 

(RQs) being less than the EPA Levels of Concern (LOCs), is that dicamba use on DGT cotton 

would not affect threatened and endangered species in the following taxa:213

 Fish, aquatic phase amphibians, and aquatic invertebrates (acute or chronic exposure)

 Birds, terrestrial-phase amphibians, and reptiles (chronic exposure)

 Mammals (acute exposure)

 Insects214

 

210 This approach calculates a risk quotient (RQ) by dividing the Estimated Environmental Concentration (EEC) by the appropriate 

toxicity endpoint, and then compares that value with the appropriate Level of Concern (LOC). The LOC is established by EPA 

policy as the criteria used by EPA in comparison to the calculated risk quotient (RQ) to assess the potential for a pesticide use to 

cause adverse effects to non-target organisms.

211 This use pattern is referred to in subsequent reports as the 6-day interval maximum-use pattern (6diMUP).

212 The proposed dicamba label for DGT cotton will not permit aerial application.

213 “If assumptions associated with the screening level action area result in RQs that are below the listed species LOCs, a “no 

effect” determination conclusion is made with respect to listed species in that taxa, and no further refinement of the action area 

is necessary.” EFED Reregistration Chapter for Dicamba/Dicamba Salts, p. 72. 

214 RQ calculations for insects are based on acute contact exposure. The RQ for the honey bee, as a surrogate for terrestrial 

invertebrates, was not a definitive value. Since there was no mortality in the acute contact exposure study, a definitive LD50 could 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 836 of 946

These conclusions for aquatic animals, birds, mammals and insects are consistent with the risk 

conclusions presented in the EFED Reregistration Chapter for Dicamba/ Dicamba Salts (USEPA, 

2005 and 2009).

The levels of concern considered by EPA for threatened and endangered (listed) species risk 

assessments are given in Table F-67.

Table F-67. EPA Levals of Concern for Threatened and Endangered Species (US EPA, 

2004)

Risk Presumption Calculation for Risk Quotient Level of Concern

Birds

Acute Risk EEC/LC50 (application of a liquid) or LD50/ft2 or 

LD50/day (application as a granule, bait, or treated 

seed)

0.1

Chronic Risk EEC/NOAEC 1.0

Wild Mammals

Acute Risk EEC/LC50 (application of a liquid) or LD50/ft2 or 

LD50/day (application of a granule, bait, or treated 

seed)

0.1

Chronic Risk EEC/NOAEC 1.0

Terrestrial Invertebrates

Acute Risk EEC/LD50 0.05

Aquatic Animals

Acute Risk EEC/LC50 or EC50 0.05

Chronic Risk EEC/MATC or NOAEC 1.0

F.4.6.1.2. Refinement to the Screening Level Analysis - Use of Dicamba-specific Foliar 

Residue Values

Consistent with EPA guidance found in the Overview Document (USEPA, 2004), if screening-level 

assessments do not result in a “no effect” determination, EPA does not then conclude that an 

herbicide “may affect” threatened and endangered species; rather, more refined assessments must be 

conducted to ascertain if any effects are expected to occur. Accordingly, for threatened and 

endangered animal species and the exposure durations for which the risk quotient exceeded the 

LOC in the screening level analysis (acute exposure for birds, amphibians and reptiles, and chronic 

exposure for mammals), refined exposure estimates were developed utilizing measured dicamba 

 

not be determined. The resulting RQ was <0.12. However, since there was no mortality in the study, and the dose tested was 

more than seven times greater than upper bound maximum default residue value for arthropods calculated from T-REX using 

the dicamba- specific foliar decline value, the initial assessment concluded that terrestrial invertebrates would not be affected by 

dicamba use on DT-soybeans. This is consistent with the dicamba science chapter (USEPA, 2005a) conclusion that dicamba is 

practically non-toxic to bees.
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residues on pasture grasses215 as representative residues for the short grass component of animal 

diets (Honegger et al., 2013). These data were from an extensive battery of residue studies 

conducted under Good Laboratory Practices by dicamba registrants. These data were used to 

estimate dicamba-specific residues for the grass components of animal diets216, instead of using the 

EPA default residue values based on the Kenaga nomogram (Hoerger and Kenaga, 1972) as revised 

by Fletcher (1994). This approach is consistent with the approach described in the Overview 

Document for certain types of pesticides (US EPA, 2004). 

In addition, a Monsanto soybean residue study, and a grass residue study and a wheat residue study 

from a dicamba registrant, included forage sampling at several time points soon after application. 

From these studies, the rate of decline of dicamba residues on soybean, grass forage, and wheat 

foliage could be determined, and the time required for dissipation of 50 percent of the Day Zero 

residues (DT50) calculated.217 The Overview Document (USEPA, 2004)218 indicates that chemicalspecific foliar dissipation values can be used for multiple application exposure modeling for wildlife; 

accordingly, as a conservative assumption, the longest of the representative dicamba-specific foliar 

DT50 values for these three crops (5.63 days, for pasture grass) was used in the calculation of the 

dicamba-specific residues for chronic exposure. For grass and broadleaf dietary items, both mean 

and upper bound residue values219 were considered in the evaluation; these levels are suitable to 

estimate realistic (mean) and worst case (upper bound) levels of exposure. A comparison of the 

default upper bound residue values and dicamba-specific upper bound residue values is given in 

Table F-68.

 

215 Residue values from these studies were converted to values expressed as parts per million per pound dicamba acid from residues 

values for application rates of 0.5, 1.0, and 2.0 lb a.e./A for grasses. 

216 The ratio of Kenaga residue values for tall vs. short grass was used with the measured pasture grass residue value to calculate a 

corresponding tall grass residue value.

217 For the pasture grass and wheat residue studies, there were over 50 treatments per study for which a DT50 value could be 

calculated. In accordance with USEPA guidance, the 90th percentile upper confidence limit of the mean DT50 value was selected 

as an appropriate DT50 value to use for calculation of residue decline for these crops. For the soybean residue study, only six 

treatments were available to calculate DT50 values; thus, the maximum value was considered to represent residue decline in 

soybean forage.

218 Overview Document (USEPA, 2004), pg. 13.

219 Considering the number of measured residue values available for pasture grasses to calculate the upper bound residue, for 

chronic exposures, use of a refined maximum residue value (90th percentile value) was still considered a “worst case” 

conservative approach and is consistent with probabilistic approaches outlined in ECOFRAM (1999).
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Table F-68. Comparison of Default Kenaga Residues and Dicamba-specific Residues in 

Food-Items 

Maximum dicamba residues in food items (ppm a.e.) based on 

a 1 lb a.e./A pre-emergence application followed by two sequential 

post-emergence 0.5 lb a.e./A applications assuming 6-day intervals 

between applications (6diMUP)

Short 

Grass Tall Grass Broadleaf Plants

Fruits/ 

Pods/Seeds Arthropods

Using upper bound Kenaga residues & default foliar DT50 (35 days)

Day 0 (after 1st application) 240.0 110.0 135.0 15.0 94.0

Maximum residuea(after 3rd

application)

415.8 190.6 233.9 26.0 162.9

Using upper bound Kenaga residues & dicamba-specific foliar DT50 (5.63 days)

Day 0 and Maximum residuea

(after 1st application) 240.0 110.0 135.0 15.0 94.0

Using Dicamba-specific maximum measured residues (short and tall grass) & foliar DT50 (5.63 days)

Day 0 and Maximum residuea 

(after 1st application) 179.0 82.0 135.0 15.0 94.0

Using Dicamba-specific refined maximum measured residues (90th percentile value for short and tall 

grasses) & foliar DT50 (5.63 days)

Day 0 and Maximum residuea

(after 1st application) 131.0 60.0 135.0 15.0 94.0

a Using the default foliar DT50, the highest residue occurs immediately after the third application. Using the dicamba-specific DT50, the highest residue occurs immediately after the first 

application.

These refined residue values for dietary items were considered when using the EPA model T-REX 

(v1.5.2; USEPA, 2013) for the calculation of risk quotients and subsequent comparison to LOCs for 

acute exposures to birds, terrestrial amphibians, and reptiles, and for chronic exposures to 

mammals.220 

Risk quotients for chronic exposure to mammals calculated using refined maximum measured upper 

bound residues slightly exceed the LOC for small and medium-sized mammals consuming short 

grass or broadleaf plants; however, utilizing mean residue values as a further refinement, risk 

quotients are all below the LOC (Table F-69) leading to a conclusion of no effect on these species. 

This is consistent with the finding in the EFED Science Chapter for dicamba (USEPA, 2005) and 

the revised RED (USEPA, 2009) for a single application rate of 1.0 lb a.e./A. Because there will be 

 

220 The T-REX model is not designed to allow modification of the dietary food item residues. Thus, the dicamba-specific residues 

reported in Table F-68 were considered in the risk quotient calculations by applying a correction factor to the estimated 

environmental concentrations (EEC) values computed using the standard T-REX model for a single 1-lb/A application.
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at most only three applications per year and dicamba dissipates rapidly, an individual small- or 

medium-sized mammal will not chronically consume foliage containing maximum residue levels 

from dicamba-treated fields. Therefore, reliance on dicamba-specific Day 0 mean residue values is 

also a conservative dietary exposure estimate for chronic exposure that is expressly countenanced by 

EPA.221 Nonetheless, a refined county-level analysis was conducted for chronic exposure to 

mammals.

Table F-69. Risk Quotients for Chronic Exposure for Mammalian Species Based on 

Dicamba-Specific Residue Values and DT50.

Diet Mammal Size 

(g)

Risk Quotienta,b 

using Upper Bound 

Residues

Risk Quotienta

using Mean Residues

Short Grass

15 1.26 0.75

35 1.08 0.64

1000 0.57 0.34

Tall Grass

15 0.58 0.32

35 0.49 0.27

1000 0.26 0.15

Broadleaf Plants

15 1.30 0.43

35 1.11 0.37

1000 0.60 0.20

Fruits/Pods

15 0.14 0.07

35 0.12 0.06

1000 0.07 0.03

Arthropods

15 0.91 0.63

35 0.77 0.54

1000 0.41 0.29

Seeds

15 0.03 0.02

35 0.03 0.01

1000 0.02 <0.01

a Dicamba-specific refined residue values based on a 1 lb a.e./A application rate were 131, 60.0, 135.0, 15.0, 94.0 and 15.0 mg 

a.e./kg diet, respectively, for upper bound values for short grass; tall grass; broadleaf plants; fruits/ pods; arthropods; and seeds, 

and 77.9, 33.0, 45.0, 7.0, 65.0 and 7.0 mg a.e./kg, respectively, for mean residues. The dicamba-specific residue decline DT50 of 

5.63 days instead of the EPA default value of 35 days was also used in determining the peak residue value resulting from the 

three sequential applications.

b Bold font indicates that the RQ exceeds the LOC (1.0).

 

221 Overview Document (USEPA, 2004), p. 40. 
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With respect to birds, analyses were performed using maximum measured dicamba residue values 

(Table F-68) for dose-based RQ calculations for acute exposure. The following could be excluded 

from concern (and, therefore, no effects would be expected to occur): birds of all sizes consuming 

only fruits/pods or seeds and large birds consuming tall grass or arthropods. Small and mediumsized birds consuming broadleaf plants, arthropods or grasses and large birds consuming short grass 

or broadleaf plants required further analysis (Table F-70). 

Refined analyses were conducted for birds for which the dose-based RQ values exceeded the LOC; 

however, this was a conservative approach since the subacute dietary-based RQ values, based on 

maximum measured upper bound residues (Table F-68), are all well below the LOC (0.1); except for 

birds consuming a short grass diet. The short grass RQ (<0.12) is not definitively below the LOC; 

however, considering that no listed species in the continental U.S. consume grasses as the primary 

diet item (Sullivan and Wisk, 2012) and taking into account the toxicity value used in the dietary 

assessment (>1522 mg/kgdiet) is actually an unbounded NOEC value, effects from short-term 

exposure to dicamba used on DGT cotton can be excluded from concern.222

Because birds are the surrogate species for terrestrial phase amphibians and reptiles, further analysis 

was also conducted to ensure that amphibians and reptiles could be excluded from concern for 

adverse effect.

Table F-70. Risk Quotients for Acute Exposure to Birds Using Maximum Measured 

Dicamba Residues and Dicamba-specific Residue Decline Values 

Diet

Acute RQs: (Dose-based EEC/adjusted LD50)a

Upper Bound Residues

20 g

Small

100 g

Medium

1000 g

Large

Short grass 1.08 0.48 0.15

Tall grass 0.49 0.22 0.07

Broadleaf plants 0.81 0.36 0.12

Fruits/pods 0.09 0.04 0.01

Arthropods 0.57 0.25 0.08

Seeds 0.02 <0.01 <0.01

 

222 The toxicity value (>1522 mg/kgdiet) used to calculate the RQ is a concentration in feed at which no effect was observed rather 

than a concentration at which 50% mortality would be predicted. The short grass EEC from Table F-68 is 179 mg/kg-food 

item. This estimated concentration on short grass that birds might be consuming is less than one eighth of the dietary 

concentration at which no effects were observed; therefore, there will be no effect on these species from short-term exposure to 

dicamba used on DGT cotton.
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Food Item

Dietary-based RQs (Dietary-based EEC/LC50 or NOAEC)

Upper Bound Residues Mean Residues

Subacute Chronic Subacute Chronic

Short grass <0.12 0.26 <0.05 0.11

Tall grass <0.05 0.12 <0.02 0.05

Broadleaf plants <0.09 0.19 <0.03 0.06

Fruits/pods/seeds <0.01 0.02 <0.01 0.01

Arthropods <0.07 0.14 <0.04 0.09

a Bold numbers indicate the RQ exceeds the LOC (0.1).

F.4.6.1.3. Refined Analysis Considering Species County-level Location

Certain sizes of threatened and endangered birds, amphibians, reptiles, and mammals had risk 

quotients exceeding the LOC as a result of the use of dicamba on DGT cotton based on a default 

exposure analysis or an analysis using refined residue and residue decline values. Consistent with 

guidance set forth in the EPA Overview Document223, a more detailed evaluation of the locations of 

these threatened and endangered species relative to potential areas of cotton production was 

undertaken. 

First, the co-occurrence of threatened or endangered species and the production of cotton was 

determined at the county level. For completeness, all threatened or endangered avian, amphibian, 

reptile, and mammalian species were included in the county-level analysis (including species 

proposed for listing, but excluding wholly aquatic species). Listing status224, species habitat and 

proximity data to cotton production at the county-level were evaluated for these identified species to 

determine which species in which counties can be excluded from further evaluation and which 

require further evaluation. This process is referred to as the “county-level analysis” (Frank and 

Kemman, 2013b) and is discussed in more detail in Section IV.F.2 below. The sub-county location 

of threatened and endangered species observations and land relevant for cotton production was also 

considered for some species. This proximity evaluation is discussed in Section IV.F.3.

F.4.6.1.4. Refined Analysis Considering Species Biological Characteristics

Next, the Overview Document provides that – for those threatened or endangered species (avian, 

reptile, amphibian (terrestrial-phase), and mammalian) that require further evaluation – each species 

be considered individually to determine whether it can be excluded from concern for potential 

 

223 Overview Document (USEPA, 2004), p. 69.

224 Listing status refers to whether the species is classified as threatened, endangered, or no longer considered threatened or 

endangered (delisted).
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effects based on body weight or dietary considerations. Accordingly, for these animal species, 

refined risk quotient calculations were performed considering individual species body weight, food 

type and food intake rate, as described in Section IV.F.4 and in Schuler et al. (2013a), and consistent 

with EPA guidance found in the Overview Document (USEPA, 2004). Based on these refined 

species-specific analyses, as discussed below, individual animal species were excluded from concern, 

and, therefore, would not be affected by dicamba use on DGT cotton.

F.4.6.2. County-level Analysis: Co-occurrence of Listed Species in Crop Production Areas

The procedures used in the county-level analysis to identify counties containing threatened or 

endangered species that require further evaluation are described in detail in Frank and Kemman 

(2013b). The U.S. counties where cotton production was reported were identified using available 

data from the U.S. Census of Agriculture. Census data from 1997, 2002 and 2007 were utilized to 

identify counties with reported cotton farms.225 Any county with a reported cotton farm was 

considered in this analysis. 226 This information was supplemented with cotton pesticide application 

data available from the California Department of Pesticide Regulation for the years 2000-2011. 

Counties without cotton production, but adjacent to counties with cotton production were also 

identified. In total, there were 1,198 counties considered in this analysis (733 cotton counties, 465 

adjacent counties). 

In the identified counties, available county-level presence information for threatened or endangered 

avian, terrestrial reptile, terrestrial-phase amphibian, and mammalian species was evaluated, using 

county-level location information compiled by the FIFRA Endangered Species Task Force (FESTF) 

and available in the FESTF Information Management System (IMS).227 Species that were wholly 

aquatic (e.g. whales) were not included. Of the 1,198 counties initially considered, there were 1,063 

counties with listed species in the taxa of interest for dicamba and where cotton is produced (or in

counties adjacent to cotton production counties). These counties reflect the reported presence of 

118 distinct species in 24 states. There were 3,181 species/county co-occurrence records considered 

across all animal taxa evaluated. In these counties, each species was evaluated with respect to the 

current listing status, county-level locations, species biology, species habitat requirements, and (when 

possible) species proximity to land relevant for cotton production, in order to determine whether 

exposure to dicamba from use on DGT cotton could potentially result in effects to the species. 

 

225 Conducted every five years, the USDA Census of Agriculture provides a detailed picture of U.S. farms and ranches and the 

people who operate them. It is the only source of uniform, comprehensive agricultural data for every state and county in the 

United States. The farm and acreage information for the 1997 census year was taken from the 2002 Census of Agriculture 

(USDA, 2004), which reports cotton information for both 1997 and 2002 census years.

226 This analysis assumed that the reported presence of a single cotton farm in any of the last three Censuses (1997, 2002, and 2007) 

was an indicator that the county contained land suitable for cotton production. 

227 The FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act) Endangered Species Task Force (FESTF) Information 

Management System 2.7 (IMS) (referred to as the “FESTF IMS”) was developed in order to meet the legal obligations of its 

member companies to submit data required by EPA/OPP under FIFRA (as described in Pesticide Registration Notice 2000-2) 

in support of the members’ registration and re-registration actions. The purpose of the IMS is to meet the data requirements in a 

manner that significantly improves the consistency, quality, availability and use of existing information on threatened and 

endangered species and pesticide use. http://www.festf.org/visitors/default.asp. 
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Some listed species could be removed from concern for effects based on exclusions that currently 

exist and are documented in Frank and Kemman (2013b). Exclusions that have been employed 

include change in species listing status, species not present due to extirpation228, habitat not in 

proximity to agriculture, lack of proximity to agricultural lands in counties with cotton farms229, 

product properties230, and species not in proximity to agriculture for other reasons. 

The proximity analysis at the sub-county level as described in Section IV.F.3 and species-specific 

refinements as described in Section IV.F.4 have been utilized in conjunction with the county-level 

identification of co-occurrences to evaluate potential effects to threatened and endangered species as 

discussed in the EPA Overview Document.231 T-REX was utilized for birds and mammals to 

calculate species- and diet-specific risk quotients. For amphibians and other relevant species, was 

utilized to calculate species- and diet-specific risk quotients for amphibians and reptiles with similar 

methods to those used in the assessments of the California red-legged frog (US EPA, 2008b). Diet 

information was utilized for individual species of birds, reptiles, and mammals to determine if actual 

diet considerations can justify removing a species from concern.

F.4.6.3. Sub-County Animal Species Observations versus Land Use Proximity Analysis

The analysis of proximity of relevant land use to sub-county locations of threatened or endangered 

animal species identified in the county-level analysis (Frank and Kemman, 2013c) is reported in 

Schuler et al. (2013a) and is summarized in the sections that follow.

F.4.6.3.1. Land Use Information

For the contiguous U.S., land cover data considered in this analysis were obtained from the National 

Land Cover Dataset (NLCD 2006) (minimum mapping unit: 30-meters)232. Data for the NLCD 

2006 dataset were collected from 2001 and 2006 and represent the best comprehensive collection of 

national land use and land cover information for the U.S (NLCD, 2011). The land cover classes of 

pasture/hay (Class 81) and cultivated crops (Class 82) were considered “relevant land use” for this 

analysis since land designated as cultivated crops could potentially be used for production of DGT 

cotton, and some pasture/hay fields could be converted to cultivated cropland. In addition, for 

California, sections where herbicide applications on cotton have been reported were also considered 

a source of land use information. 

 

228 An extirpated species is defined as “a species no longer surviving in regions that were once part of its range” 

(http://www.fws.gov/midwest/endangered/glossary/index.html).

229 Based on National Land Cover Database (NLCD) 2006 land use information.

230 A Product Property exclusion is based on a quantitative analysis of dicamba properties beyond the screening level analysis in the 

EFED Reregistration Chapter (USEPA, 2005). Specifically, this analysis involves assessing use of measured foliar residues and 

foliar decline rates following dicamba applications, adjusted to reflect the use pattern for DGT cotton. The size and diet of the 

animal species are also considered. 

231 Overview Document (USEPA, 2004), p. 69 and p. 67, respectively.

232 National Land Cover Database 2006 (NLCD 2006). URL: http://www.mrlc.gov/nlcd2006.php
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F.4.6.3.2. Species Locations

FESTF Multi- Jurisdictional Database (MJD)

Threatened and endangered animal species location data at a sub-county level were obtained from 

the FIFRA Endangered Species Task Force Multi-Jurisdictional Database (FESTF MJD; 

NatureServe 2012). The FESTF MJD consists of a “licensed dataset” drawn from NatureServe’s 

Multi-Jurisdictional Database (MJD) licensed to FESTF.233 The MJD species observation records 

included additional data fields, such as date of last observation and observation notes; this 

information was evaluated and utilized when relevant to the proximity assessment.

The MJD location data were provided as polygons (areas representing where a listed species was 

observed; referred to as a “species observation”). The spatial dataset was provided in a format 

suitable for analysis and display using Geographic Information System (GIS) software.

For the purposes of this analysis, species observations were considered “historic” if the “last 

observed date” for the observation (as reported by NatureServe in the FESTF MJD 2012 dataset) 

was prior to 1977 234 or if the observation was noted to be “Historical” or “Extirpated” in the 

FESTF MJD 2012 dataset licensed from NatureServe.

F.4.6.3.3. Proximity Analysis Process

Proximity distances from each species observation (polygon) in the FESTF MJD 2012 dataset to 

NLCD 2006 Class 81 (Pasture/Hay) and Class 82 (Cultivated Crops) land area were available, and 

were used to evaluate potential proximity to land suitable for cotton production. The FIFRA 

Endangered Species Task Force used the MJD 2012 dataset to prepare a database entitled “FESTF 

MJD 2012/NLCD 2006 Species Occurrence/Land Cover Proximity Database – Classes 81 and 82”, 

and Classes 81 and 82 were included in this database. From this database, the nearest distance of a 

species observation to relevant land use in a cotton production county was extracted for each 

species/county co-occurrence evaluated in Frank and Kemman (2013c).

Under the proximity analysis process, the distance evaluated for proximity of a species to relevant 

land use for cotton production was determined based on each species’ home range, i.e., the area over 

which an animal normally travels and searches for food. A species may be excluded from concern in 

a particular county if the nearest distance of current species observations235 in that county to land 

 

233 Under the terms of the FESTF license with NatureServe, the sub-county threatened and endangered species location data are 

confidential information available only to FESTF, FESTF member companies (including FESTF “Level II” companies), and 

EPA-OPP (Office of Pesticide Programs) staff reviewing FESTF member-company registrations. Information based on the 

sub-county species location data may be shared with cooperating federal and state agencies for regulatory decision-making 

related to endangered species assessments for Monsanto products.

234 A time period for observations beginning in 1977 is considered a conservative time period for this analysis.

235 For the purposes of this analysis, species observations were not considered current if the last observed date was prior to 1977, or 

the observation was classified as Historical or Extirpated (as reported by NatureServe in the MJD 2012 dataset).
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relevant for cotton production was greater than the species’ home range, based on best available 

information (on home range and on cotton production areas).

The California Pesticide Using Reporting database was also utilized to identify Public Land Survey 

Sections in the 13 California counties considered to have cotton production, based on Census of 

Agriculture information, where pesticide applications had been made to cotton, and hence were 

sections where cotton has been grown. Pesticide Use Reports for the years 2000–2011 were used 

for this determination.

F.4.6.4. Species-specific Risk Quotient Calculations

Consistent with EPA’s Overview Document, species-specific dietary exposure was assessed 

considering animal body weight and diet (Schuler et al., 2013a) for birds and mammals of certain 

sizes, where risk quotients exceeded the level of concern after the initial refinements described 

above. A similar assessment was conducted for amphibians and reptiles because birds serve as the 

surrogate for terrestrial phase amphibians and reptiles. Biological information was gathered from a 

number of sources, including U.S. Fish and Wildlife Service (USFWS) species recovery plans, 

primary literature, and other technical sources (e.g. NatureServe236).

F.4.6.4.1. Mammals

In the county-level endangered species analysis, 51 threatened or endangered mammalian species 

were identified as potentially being present in or adjacent to a county with cotton production (Frank 

and Kemman, 2013c). Of the original 51 species, 11 species were removed from consideration 

based on Habitat determinations and 6 species were deemed Not of Concern237 across all the 

counties evaluated (Frank and Kemman, 2013c).

The remaining 34 species of mammals were examined for the potential for chronic effects based on 

proximity to land relevant for cotton production and biological characteristics (i.e., dietary 

preferences and body size). The analysis progressed in a step-wise fashion (see Schuler et al., 2013c):

 The proximity of each species observation to relevant land use for cotton production was 

compared to species home range information. Of the 34 species evaluated in this refined 

analysis, 5 species were excluded from concern due to lack of proximity to land relevant for 

cotton production,

238 and 6 additional species were excluded from concern based on a 

combination of Not of Concern and Proximity determinations.

 

236 NatureServe is a non-profit conservation organization that collects detailed local information on plants, animals, and ecosystems. 

NatureServe has a public website available at http://www.natureserve.org .

237 “Not of Concern” Determination: Species co-occurrences that are not of concern. Physical or regulatory factors provide clear evidence 

that a species is not of concern in a particular county. Examples include delisted species, no current presence, and historical or 

extirpated species. 

238 For all county co-occurrences that did not have applicable Not of Concern determinations.
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 The 23 remaining species received Product Property determinations (Diet Exclusions)239, 

since based on body size and diet, the RQs were less than LOC considering chronic 

exposure to upper bound residues.

 All calculations were based on the assumption that animals eat 100% of their diet at the 

upper bound residue levels. This is an extremely conservative assumption for a chronic 

exposure scenario. Based on the EPA Overview Document for Endangered and Threatened 

Species Effects Determinations (US EPA 2004), the use of the mean residue value is an 

appropriate refinement for chronic exposures. When consumption of food containing the 

mean residue value is assumed, the dose-based chronic risk quotients are well below the 

LOC of 1 (Table F-69) for all diet types and body sizes, indicating that threatened or 

endangered wild mammals can be excluded from concern and, therefore, would not be 

affected. 240

 The Diet Exclusion was also applicable to the species assigned Proximity or Not of Concern 

determinations, resulting in a total of 34 mammalian species where a Diet Exclusion was 

applicable.

In summary, it can be concluded that no effects to mammalian species will result from the use of 

dicamba on DGT cotton.

F.4.6.4.2. Birds

In the county-level endangered species analysis, 37 threatened or endangered avian species were 

identified as potentially being present in or adjacent to a county with cotton production (Frank and 

Kemman 2013b).

 Of the original 37 species, 4 species were removed from consideration based on Habitat 

determinations, and 1 species was deemed Not of Concern237 across all the counties 

evaluated (Frank and Kemman 2013c).

 For the remaining species, the proximity of each species observation to relevant land use for 

cotton production was compared to species home range information. Of the 32 species 

evaluated in the refined analysis, 3 were removed from concern due to a lack of proximity to 

land relevant for cotton production,241 and an additional 4 species were excluded from 

 

239 This determination type identifies a particular species or taxon as not at risk based on the properties of the product (dicamba 

applied to DGT cotton) when certain biological factors such as size (e.g. >1 kg) and diet (e.g., carnivorous, frugivorous, etc.) are 

considered.

240 Considering the rapid rate of dicamba foliar residue dissipation, even chronic RQs calculated for small mammals with the refined 

maximum measured residues only exceed the LOC for up to 2 days, not a sufficient duration to be considered a chronic 

exposure

241 For all county co-occurrences that did not have applicable Not of Concern determinations.
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concern based on a combination of Not of Concern and Proximity determinations (Schuler 

et al, 2013c).

 Of the remaining species evaluated in this refined analysis, 14 were assigned Product 

Property determinations (Diet Exclusion) as the primary determination because their T-REX 

acute RQs were less than the LOC based on characteristics of diet and body weight or their 

diets did not include items considered in the T-REX model (e.g., aquatic animals) (Schuler et 

al., 2013c).242

 Using measured upper-bound dicamba residue values, RQ values exceeded the acute LOC 

of 0.1 only for small and medium-sized birds that consume grasses, broadleaf plants, or 

arthropods, and large birds consuming short grass and broadleaf plants.

 Dose-based RQs calculated for 11 species using the acute LD50 value exceeded the acute 

LOC of 0.1 for the dose-based upper bound residues indicating that further refinement 

should be considered (described below).

 Based on the refinements (see Schuler et al., 2013a), these remaining 11 species were 

assigned Product Property determinations (Feeding Exclusion)243 because the upper bound 

EECs calculated for these species were lower than dose-based NOELs calculated from acute 

dietary exposure studies.

 The Diet and Feeding Exclusions were also applicable to the species assigned Proximity or 

Not of Concern determinations, resulting in totals of 15 species where a Diet Exclusion was 

applicable, and 17 species where a Feeding Exclusion was applicable.

Moreover, this analysis is conservative because it is likely that the birds would not be in cotton fields 

actively foraging, but rather foraging in the adjacent habitats (e.g., tree canopy) outside of the fields. 

Threatened and endangered species are strongly associated with their specific habitat type and, 

therefore, it is improbable that 100% of the bird’s diet would consist of dietary items exposed to 

dicamba in the field. Additionally, EPA’s default approach to assessing acute risk is based on a 

single oral gavage dose (i.e., the entire dose is delivered to the animal at one time, typically after 

being dissolved in corn oil). In reality, of course, any pesticide exposure will not occur in this

manner – but rather through dietary consumption of dicamba-exposed prey or food items. As a 

result, the gavage route of administration overestimates the exposure expected to occur in nature, 

 

242 Diet items not included in T-REX were aquatic animals and small- to medium-sized mammals as prey. Exposure to dicamba 

residues from the consumption of aquatic animals was not considered to be of concern due to low surface water concentrations 

(Honegger et al., 2013) and a low bioconcentration factor (BCF). Consumption of small- to medium-sized wild mammals by 

large carnivorous mammals (i.e. 1 kg or larger) is not a concern because dicamba does not bioaccumulate in mammalian tissues 

(U.S. EPA, 2005) and residues from food items that a prey might have consumed would not result in RQs exceeding the LOC 

for species of 1 kg or larger.

243 This determination type identifies a particular species as not at risk based on the properties of the product (dicamba applied to 

DGT cotton) when certain biological factors such as size (e.g. >1 kg) and diet (e.g., carnivorous, frugivorous, etc.) are 

considered.
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and methods resulting in a dose-delivery over time (e.g., dietary exposure) are more environmentally 

relevant. Therefore, the use of the acute oral toxicity test (i.e., oral gavage) to predict risk of 

dicamba to birds in this case should be considered to be a screening-level approach that is expected 

to overestimate actual risk.

An acceptable refinement to the screening level risk assessment, based on guidance in the US EPA 

Overview Document on Ecological Risk Assessment Process for Endangered and Threatened 

Species Effects Determinations (USEPA, 2004), is to determine the acute risk to birds from 

consuming dicamba exposed prey or food items from an estimate of the dose-based effect levels 

calculated from acute dietary toxicity studies.

 From short-term dietary toxicity tests using bobwhite quail chicks and mallard ducklings 

exposed to dicamba diglycolamine salt for 5 d, the dose-based NOEL values were 

determined (Grimes, 1986a; Grimes, 1986b). The use of the NOEL value in place of the 

LC50 for an acute assessment provides additional conservatism when assessing for potential 

effects on endangered species.

 For birds, the dose-based EECs were calculated based on the refined foliar residue and DT50 

values and assuming 100% diet was obtained within the field. The short/tall grass residue 

values were refined based on the maximum measured Day 0 residues from 59 dicamba 

specific field trials in pasture grasses.

 From this analysis, the dose-based EECs for small passerine birds consuming a diet exposed 

in the field are below the dose-based NOEL values (Schuler et al., 2013c).

 Conservatively assuming that the avian species evaluated are passerine species (highest 

metabolic/ingestion rates, U.S. EPA, 1993), they cannot ingest enough food to achieve 

doses that would exceed the unbounded NOEL (highest dose tested).

 In addition, compared to the larger birds used in the gavage study (e.g., 178 g and 1,580 g for 

the bobwhite quail and mallard duck, respectively), the sizes of birds used in the dietary 

studies (e.g., 37 g and 264 g for the bobwhite quail and mallard duck, respectively) are much 

more relevant to birds considered in this analysis; thereby reducing uncertainty in the toxicity 

value adjustment.

In summary, it can be concluded that no effects to birds will result from the use of dicamba on 

DGT cotton.

F.4.6.4.3. Amphibians and Reptiles

In the county-level endangered species analysis, 13 terrestrial-phase amphibian species and 17 reptile 

species were identified as potentially being in or adjacent to a county with cotton production (Frank 

and Kemman, 2013c). Of these species, 1 amphibian and 4 reptile species were removed from 

consideration based on Habitat determinations. Additionally, 1 reptile species was deemed Not of 

Concern across all counties evaluated (Frank and Kemman, 2013c).

The remaining 12 amphibian and 12 reptile species were evaluated based on their proximity to 

agriculture and species-specific refinements (Schuler et al, 2013c). 
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 The proximity of each species observation to relevant land use for cotton production was 

compared to species home range information. Two reptile species were removed from 

concern due to a lack of proximity to land relevant for cotton production.244 Three 

amphibian species and two additional reptile species were excluded from concern based on a 

combination of Not of Concern and Proximity determinations (Schuler et al, 2013c).

 The remaining species (9 amphibian species and 8 reptile species) all received Product 

Property determinations (Diet Exclusion) because their T-HERPS RQ values were less than 

the LOC based on characteristics of diet and body weight.

 The Diet Exclusion was also applicable to the species assigned Proximity or Not of Concern 

determinations, resulting in totals of 12 amphibian and 12 reptile species where a Diet 

Exclusion was applicable.

In summary, it can be concluded that no effects to terrestrial-phase amphibians or terrestrial reptiles 

will result from the use of dicamba on DGT cotton.

F.4.6.5. Indirect Effects on Threatened and Endangered Species of Other Taxa Resulting 

from Direct Effects on Plant Species

To assess the potential for indirect effects on threatened and endangered species, the EPA evaluates 

the risk of direct effects on non-endangered species from relevant taxonomic groups to make 

inferences concerning the potential for indirect effects upon threatened or endangered species that

rely on non-endangered species in that category for critical resources. For threatened and 

endangered species that have an obligate relationship with another species, EPA evaluates the risk of 

direct effects on the listed species from relevant taxonomic groups to make inferences concerning 

the potential for indirect effects upon threatened or endangered species (USEPA, 2004).

Through a combination of screening level and refined exposure analyses (Honegger, et al., 2013; 

Schuler et al., 2013c), all terrestrial and aquatic animal taxa have been excluded from concern for 

potential effects on threatened and endangered species of these taxa from the use of dicamba on 

cotton with the DT trait. Similarly, vascular aquatic plants and monocotyledonous terrestrial plants 

have been excluded from concern for potential effects on threatened and endangered species of 

these taxa. There are currently no listed non-vascular aquatic plants, and the RQ is below the LOC 

for non-listed non-vascular plants. These results indicate that these taxa can be removed from 

concern for indirect effects on other taxa from the use of dicamba on cotton with the DT trait.

The RQ values used to assess the potential for indirect effects from dicamba applications to cotton 

with the DT trait indicate that indirect effects to other taxa as a result of effects on dicot plant 

species from a combination of sheet runoff and spray drift to soil would not occur (Honegger et al., 

2013). In addition, utilizing a refined exposure assessment, indirect effects to other taxa resulting 

from effects on dicot plant species exposed via a combination of channelized runoff and spray drift 

 

244 For all county co-occurrences that did not have applicable Not of Concern determinations.
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to soil would be extremely unlikely (Honegger et al., 2013). When RQ values are calculated for all 

six of the dicot species tested in the vegetative vigor study, RQs exceed the LOC for only two of the 

six species indicating that habitat and food sources from dicot plants will be present adjacent to 

areas treated with dicamba (Honegger et al., 2013). Furthermore, field studies demonstrate that even 

very sensitive plants at the edge of a field sprayed with dicamba are not affected to the extent that 

impacts on habitat would result. Additionally, effects from drift can be further minimized through 

the use of application requirements such as drift reducing technologies (e.g., low drift spray nozzles, 

boom height, deposition aides).

To be conservative in the analysis of potential risk of indirect effects, a separate report (Schuler et 

al., 2013d) further assesses the potential for indirect effects on threatened or endangered terrestrial 

animal species and concludes that none of the 159 listed animal species in or adjacent to cotton 

production counties will be subject to indirect effects resulting from direct effects to terrestrial 

plants from exposure to dicamba use on cotton containing the DT-trait. This analysis considered 

proximity data (home range to agricultural land relevant for cotton production) and species-specific 

biological and habitat information, in addition to an evaluation of dicamba-specific impacts to offtarget terrestrial plants for dependent species, to more accurately describe the risk associated with 

dicamba use on cotton containing the DT-trait. This analysis also concluded that there would be no 

effects to the designated critical habitat for any of the species evaluated based on a proximity 

analysis of the separation distance between critical habitat locations and agricultural lands relevant 

for cotton production or a determination that the vegetation-based PCEs of the listed animal species 

critical habitat would not be affected by dicamba.

F.4.6.6. Conclusions

In the EFED ecological risk assessment conducted for dicamba reregistration (USEPA, 2005), using 

a screening level assessment, EPA scientists concluded that a “no effect” determination can be made 

for all dicamba uses for listed fish and aquatic invertebrates. The potential for adverse effects to 

listed birds and mammals could not be excluded based on the EPA screening level assessment, the 

initial phase of analysis. Recognizing that screening level analysis is only the first step in evaluating 

impacts on threatened and endangered species, the EFED Reregistration Chapter (USEPA, 2005) 

indicates that “additional information on the biology of listed species, the locations of these species, 

and the locations of the use sites...could be considered along with available information on the fate 

and transport properties of the pesticide to determine the extent to which screening assumptions 

regarding an action area apply to a particular listed organism.”

This discussion summarizes the conclusions of other reports submitted to EPA (Honegger et al., 

2013; Frank and Kemman, 2013c; Schuler et al., 2013c & d) that utilize some of the refinements 

described by EPA in the previous paragraph to evaluate the potential for adverse effects to listed 

birds and mammals as well as amphibians, reptiles, and terrestrial invertebrates. When the 

properties of dicamba and species-specific information are taken into account, these reports 

demonstrate that listed birds, mammals, amphibians, reptiles and terrestrial invertebrates would not 

be affected directly or indirectly by dicamba use in cotton with the DT trait. 

F.4.7. Potential for GE Plant to Affect Threatened or Endangered Species

APHIS’ regulatory authority over genetically engineered (GE) organisms under the PPA is limited to 

those GE organisms for which it has reason to believe might be a plant pest or those for which 
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APHIS does not have sufficient information to determine that the GE organism is unlikely to pose a 

plant pest risk (7 CFR 340.1). EPA has sole authority to regulate the use of any herbicide. After 

completing a plant pest risk analysis, if APHIS determines that the GE organism does not pose a 

plant pest risk, then the GE organism would no longer be subject to the plant pest provisions of the 

PPA or to the regulatory requirements of 7 CFR part 340 and, therefore, APHIS will grant a 

determination of nonregulated status.

In accordance with the ESA, APHIS will review its action under the PPA relative to the GE 

organism to determine if its action may affect listed species or critical habitat, just as EPA reviews 

and regulates herbicides to determine impact on threatened and endangered species and/or critical 

habitats. Monsanto has prepared the information in this environmental report to assist APHIS in 

making this determination from DT soybean and DGT cotton. In it review, for each GE plant, 

APHIS considers the following information, data, and questions:

 A review of the biology and taxonomy of the crop plant and its sexually compatible relatives; 

 Characterization of each transgene with respect to its structure and function and the nature 

of the organism from which it was obtained; 

 A determination of where the new transgene and its products (if any) are produced in the 

plant and their quantity; 

 A review of the agronomic performance of the plant, including disease and pest 

susceptibilities, weediness potential, and agronomic and environmental impacts; 

 Determination of the concentrations of known plant toxicants (if any are known in the 

plant); 

 Analysis to determine if the transgenic plant is sexually compatible with any threatened or 

endangered plant species or a host of any threatened or endangered plant or animal species; 

and

 Any other information that may inform the potential for an organism to pose a plant pest 

risk.

F.4.8. Potential for DT Soybean to Affect Threatened or Endangered Species

To identify any potential effects of DT soybean on threatened or endangered plant species, the 

potential for DT soybean to cross with a listed species was evaluated. Soybean is not native to the 

U.S., and DT soybean is not sexually compatible with any federally listed TES or a species proposed 

for listing. Like other G. max, DT soybean will likely be a poor competitor with native vegetation 

and will not survive outside of cultivation (Baker, 1965). Thus, DT soybean is not expected to 

interbreed with any plant species or displace natural vegetation in the U.S. 

To identify potential effects on threatened or endangered animal species, the risks to threatened or

endangered animals from consuming DT soybean or vegetative materials are considered. In this 

analysis, the biology of DT soybean and the agricultural practices associated with the cultivation of 

DT Soybean have been considered for potential adverse impact on TES and their critical habitats. 

As explained in Appendices H and I, bioinformatics analysis determined that MON 87708 DMO 

does not share amino acid sequence similarities with known allergens, gliadins, glutenins, or protein 

toxins. MON 87708 DMO was rapidly digested in in vitro assays using simulated gastric and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 852 of 946

intestinal fluids and did not show any adverse effects when administered to mice via oral gavage at 

levels far in excess of that reasonably expected to be consumed by humans or animals. Compared 

to commercially cultivated soybean, DT soybean does not express any additional proteins or natural 

toxicants that are known to directly or indirectly affect a listed TES or species proposed for listing 

by the U.S. Fish and Wildlife Service. Compositional analysis of DT soybean for nutrients and antinutrients indicated that the harvested seed and forage from DT soybean were compositionally 

equivalent to commercially cultivated soybean. Thus, DT soybean would not be expected to have 

any impacts on TES that would differ from commercially cultivated soybean.

The only TES animal listed that occupies habitat that is likely to include soybean fields and that 

might feed on soybean is the Federally Endangered Delmarva Peninsula Fox Squirrel, Sciurus niger 

cinereus, found in areas of the mid-Atlantic Eastern seaboard.245 It is known to utilize certain 

agricultural lands readily, and its diet includes acorns, nuts/seeds of hickory, beech, walnut, and 

loblolly pine, buds and flowers of trees, fungi, insects, fruit, and an occasional bird egg. Given its 

varied diet, the safety of MON 87708 DMO, and the demonstrated compositional, agronomic and 

phenotypic equivalence of DT soybean to commercially cultivated soybean, it is concluded that no 

biologically significant changes to the habitat or diet of the Delmarva Peninsula Fox Squirrel are 

expected. Consequently, the planting of DT soybean is not expected to impact the Delmarva 

Peninsula Fox Squirrel. 

As part of the analysis for TES and critical habitat, Monsanto considered whether DT soybean has 

any characteristics that may allow the plant to naturalize in the environment and potentially have an 

effect on TES. In doing so, Monsanto assessed whether DT soybean is any more likely to become a 

weed than commercially cultivated soybean. Weediness could potentially affect TES or critical 

habitat if DT soybean were to become naturalized in the environment. As discussed in Appendix 

G, cultivated soybean is largely self-pollinating, with minimal gene movement. With the exception 

of its tolerance to dicamba, DT soybean has been shown to be no different from commercially 

cultivated soybean in its phenotypic, agronomic and ecological characteristics, including pollen 

diameter, viability, and morphology. In addition, DT soybean is not different from commercially 

cultivated soybean in terms of seed dormancy and germination, susceptibility to or tolerance of 

disease or insect pests, and response to abiotic stressors (such as compaction, drought, high winds, 

nutrient deficiency, etc.), and would, therefore be no different than commercially cultivated soybean 

in its potential for volunteers and feral populations. In particular, the lack of hard seed, a wellaccepted characteristic often associated with plants that are weeds, supports a conclusion of no 

increased weediness of DT soybean compared to commercially cultivated soybean. Collectively, this 

information indicates that DT soybean is no different from commercially cultivated soybean in its 

weediness potential.

In summary, no stressor associated with the introduction of DT soybean is expected to affect the 

reproduction, numbers, or distribution of a listed TES, candidate species, or species proposed for 

listing. As a result, a detailed site-specific (or spatially explicit) exposure analysis for individually 

listed TES is not necessary. Collectively, all the laboratory and field trial data on DT soybean 

 

245 Source is from website http://ecos.fws.gov/tess_public/SpeciesReport.do.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 853 of 946

support the conclusion that there would be no difference with cultivation of DT soybean from 

effects that would occur from the production of commercially cultivated soybean. Soybean is not 

native to the U.S., and DT soybean is not sexually compatible with any federally listed TES or a 

species proposed for listing. Like other G. max, DT soybean will likely be a poor competitor with 

native vegetation and will not survive outside of cultivation (Baker, 1965). Thus, DT soybean is not 

expected to interbreed with any plant species or displace natural vegetation in the U.S.

F.4.9. Potential for DGT Cotton to Affect Threatened or Endangered Species

To identify any potential effects of DGT cotton on threatened or endangered plant species, the 

potential for DGT cotton to cross with a listed species was evaluated. Cotton is in the genus 

Gossypium and has the ability to cross with some other species of cotton in the same genus (OECD 

2008). A review of the list of threatened or endangered plant species in the U.S. shows that DGT 

cotton would not be sexually compatible with any listed threatened or endangered plant species, 

species proposed for listing, or candidate species, as none of these listed, proposed, or candidate 

species are in the same genus or known to cross pollinate with species of the genus Gossypium 

(USFWS 2012; 2013). As discussed in Appendix G, there is only one native Gossypium species found 

in U.S. cotton-growing regions, in Arizona, and cross-pollination of that species with commercial 

cotton would not produce fertile offspring (Fryxell 1984; Waghmare et al. 2005). 

To identify potential effects on threatened and endangered animal species, the risks to threatened 

and endangered animals from consuming DGT cotton, cottonseed or vegetative materials are 

considered. As discussed in Appendix G, there is no difference in the composition and nutritional 

quality of DGT cottonseed compared with commercially cultivated cottonseed. The allergenicity 

and toxicity of the MON 88701 DMO and PAT(bar) proteins were also evaluated. The research 

summarized and referenced in Appendices H and I found no differences in allergenicity and toxicity 

compared to the analogous protein in commercially cultivated cotton. Both types of proteins are 

ubiquitous in nature and normally present in food and feeds derived from these plant and microbial 

sources. As discussed in Appendix G, during field trials with DGT cotton, no biologically relevant 

changes in arthropod feeding damage were observed, indicating similar arthropod susceptibility for 

DGT cotton compared to commercially cultivated cotton. As DGT cotton exhibits no toxic effects 

on insects or other animals it is concluded that they will not be affected. In addition, the cultivation 

of DGT cotton does not impact the nutritional quality, safety or availability of animal feed. Based 

on these results, no effects to any TES animal species (or candidate species, or species proposed for 

listing) that may feed on DGT cotton plant parts would be expected.

As part of the analysis for TES and critical habitat, Monsanto considered whether DGT cotton has 

any characteristics that may allow the plant to naturalize in the environment and potentially have an 

effect on TES. In doing so, Monsanto assessed whether DGT cotton is any more likely to become a 

weed than commercially cultivated cotton. Weediness could potentially affect TES or critical habitat 

if DGT cotton were to become naturalized in the environment. As discussed under Appendix G, 

cultivated cotton is largely self-pollinating, and no wild (native) or feral species of Gossypium have 

been found in cotton-growing areas. With the exception of its tolerances to both dicamba and 

glufosinate, DGT cotton has been shown to be no different from commercially cultivated cotton in 

its phenotypic, agronomic and ecological characteristics, including pollen diameter, viability, and 

morphology. In addition, DGT cotton is not different from commercially cultivated cotton in terms 

of seed dormancy and germination, susceptibility to or tolerance of disease or insect pests, and 

response to abiotic stressors (such as compaction, drought, high winds, nutrient deficiency, etc.), and 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 854 of 946

would, therefore be no different than commercially cultivated cotton in its potential for volunteers 

and feral populations. In particular, the lack of hard seed, a well-accepted characteristic often 

associated with plants that are weeds, supports a conclusion of no increased weediness of DGT 

cotton compared to commercially cultivated cotton. Collectively, this information indicates that 

DGT cotton is no different from commercially cultivated cotton in its weediness potential.

In summary, no stressor associated with the introduction of DGT cotton is expected to affect the 

reproduction, numbers, or distribution of a listed TES, candidate species, or species proposed for 

listing. As a result, a detailed site-specific (or spatially explicit) exposure analysis for individually 

listed TES is not necessary. Collectively, all the laboratory and field trial data on DGT cotton 

support the conclusion that there would be no difference with cultivation of DGT cotton from 

effects that would occur from the production of commercially cultivated cotton. Cotton is not 

sexually compatible with, nor does it serve as a host species for, any listed species, candidate species 

or species proposed for listing. Based on the characteristics of the introduced protein and 

comparative compositional assessments, consumption of DGT cotton by any listed species or 

species proposed for listing will not result in a toxic or allergic reaction. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 855 of 946

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Dicamba Use in Dicamba-Tolerant Soybeans. Sub-County Proximity Analysis for Listed Plants: Part 

2 of 2: Eastern U.S. States. Monsanto Technical Report MSL-22549. Unpublished data.

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Dicamba Use in Dicamba-Tolerant Soybeans. Sub-County Proximity Analysis for Listed Plants: 

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Dicamba Use in Dicamba-Tolerant Soybeans: A County-Level Analysis for Plant Taxa. Monsanto 

Technical Report MSL-23442. MRID 48900402. Unpublished data.

Frank AR, Kemman R. 2013a. Information to Support an Endangered Species Assessment for 

Dicamba Use in Dicamba-Tolerant Soybeans: A County-Level Analysis for Animal Taxa. (2013 

Update). Monsanto Technical Report MSL-24678. MRID49022403. Unpublished data.

Frank AR, Kemman R. 2013b. Information to Support an Endangered Species Assessment for 

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Plant Taxa. Monsanto Technical Report MSL0025083. Unpublished data

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Dicamba Use in Cotton Containing the Dicamba Tolerance Trait: A County-Level Analysis for 

Animal Taxa. Monsanto Report No. MSL0025081. MRID 49221303. Unpublished data

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Honegger JL. 2012a. Information to Support an Endangered Species Assessment for Dicamba Use 

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Honegger JL. 2012b. Overview of Proposed Approach to Address the Potential for Off-site 

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MSL0024401. MRID 48892302. Unpublished data.
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Honegger JL. 2013a. Information to Support an Endangered Species Assessment for Dicamba Use 

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Effects. Monsanto Technical Report MSL-24667. Unpublished data.

Honegger JL. 2013b. Information to Support an Endangered Species Assessment for Dicamba Use 

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Exposure and Biological Effects for Animals. Monsanto Technical Report MSL0025078. MRID

49221302. Unpublished data.

Honegger JL. 2013c. Information to Support an Endangered Species Assessment for Dicamba Use 

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Konkel G, Frank AR. 2012. Proximity of Species Occurrences and Designated Critical Habitat to 

Land Cover. October 1, 2012. FIFRA Endangered Species Task Force (FESTF), Washington, DC. 

MRID 48969505

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Application to Dicamba-Tolerant Soybean MON 87708 × MON 89788. Monsanto Study Number 

REG-09-167. Monsanto Technical Report MSL-22493. MRID 48644209. Unpublished data.

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APPENDIX G: CHARACTER AND QUALITY OF DT SOYBEAN AND DGT COTTON 

TRAITS
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 862 of 946

Table of Contents

G.1. Introduction ......................................................................................................................................864

G.2. Dicamba-Tolerant Soybean (DT Soybean) ..................................................................................864

G.2.1. Product Description...........................................................................................................864

G.2.2. Data and Information Presented Confirm the Lack of Plant Pest Potential of 

DT soybean Compared to Conventional Soybean........................................................865

G.2.3. Soybean is a Familiar Crop Lacking Weedy Characteristics.........................................866

G.2.4. Conventional Soybean A3525 is an Appropriate Comparator to DT Soybean ........867

G.2.5. Molecular Characterization Verifies the Integrity and Stability of the Inserted 

DNA in DT Soybean.........................................................................................................867

G.2.6. Data Confirm DT Soybean DMO Safety .......................................................................867

G.2.7. DT Soybean is Compositionally Equivalent to Conventional Soybean .....................868

G.2.8. DT Soybean Does Not Change Soybean Plant Pest Potential or 

Environmental Interactions..............................................................................................869

G.2.9. DT Soybean Will Not Adversely Affect NTOs or Threatened and 

Endangered Species............................................................................................................872

G.2.10. Deregulation of DT Soybean Will Not Significantly Impact Soybean 

Agronomic Practices or Land Use ...................................................................................872

G.2.11. Conclusion...........................................................................................................................873

G.3. Dicamba and Glufosinate-Tolerant Cotton (DGT Cotton)......................................................873

G.3.1. Product Description...........................................................................................................873

G.3.2. Data and Information Presented Confirms the Lack of Plant Pest Potential 

and the Food and Feed Safety of DGT Cotton Compared to Conventional 

Cotton 874

G.3.3. Cotton is a Familiar Crop Lacking Weedy Characteristics...........................................875

G.3.4. Conventional Cotton Coker 130 is an Appropriate Comparator to DGT 

Cotton 876

G.3.5. Molecular Characterization Verified the Integrity and Stability of the Inserted 

DNA in DGT Cotton........................................................................................................876

G.3.6. Data Confirms MON 88701 DMO and PAT (bar) Protein Safety .............................877
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 863 of 946

G.3.7. DGT Cotton is Compositionally Equivalent to Conventional Commercial 

Cotton 877

G.3.8. DGT Cotton Does Not Change Cotton Plant Pest Potential or 

Environmental Interactions..............................................................................................878

G.3.9. DGT Cotton Will Not Adversely Affect NTOs or Threatened and 

Endangered Species............................................................................................................880

G.3.10. Deregulation of DGT Cotton is Not Likely to Impact Cotton Agronomic 

Practices or Land Use ........................................................................................................881

G.3.11. Conclusion...........................................................................................................................882

G.4. Adverse Consequences of Introduction .......................................................................................882
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 864 of 946

G.1. Introduction

The Animal and Plant Health Inspection Service (APHIS) of the United States Department of 

Agriculture (USDA) has responsibility under the Plant Protection Act (Title IV Pub. L. 106-224, 114 

Stat. 438, 7 U.S.C. § 7701-7772) to prevent the introduction and dissemination of plant pests into 

the U.S. APHIS regulation 7 CFR § 340.6 provides that an applicant may petition APHIS to 

evaluate submitted data to determine that a particular regulated article does not present a plant pest 

risk and no longer should be regulated. If APHIS determines that the regulated article does not 

present a plant pest risk, the petition is granted, thereby allowing unrestricted introduction of the 

article.

Monsanto Company has submitted requests to APHIS for determinations of nonregulated status for 

two new biotechnology-derived products, soybean MON 87708 (DT soybean) and cotton 

MON 88701 (DGT cotton). These requests include DT soybean, DGT cotton, any progeny derived 

from crosses between DT soybean and conventional soybean and DGT cotton and conventional 

cotton, and any progeny derived from crosses of DT soybean and DGT cotton with biotechnologyderived soybean or cotton, respectively, that have previously been granted nonregulated status under 

7 CFR Part 340.

G.2. Dicamba-Tolerant Soybean (DT Soybean) 

G.2.1. Product Description

Monsanto Company has developed biotechnology-derived soybean MON 87708 (DT soybean) that 

is tolerant to dicamba (3,6-dichloro-2-methoxybenzoic acid) herbicide. DT soybean offers growers 

an expanded use of dicamba in soybean production from the current preplant and preharvest labeled 

uses. The tolerance of DT soybean to dicamba facilitates a wider window of application in soybean, 

allowing preemergence application up to the day of crop emergence and in-crop postemergence 

applications through the early reproductive (R1/R2) growth stage. Dicamba provides effective 

control of over 95 annual and biennial weed species, and suppression of over 100 perennial 

broadleaf and woody plant species. Dicamba is efficacious on broadleaf weeds that are hard-tocontrol with glyphosate, such as common lambsquarters, hemp sesbania, morning glory species, 

nightshade, Pennsylvania smartweed, prickly sida, velvetleaf, waterhemp and wild buckwheat. Hardto-control weeds generally require a higher rate and/or application at a smaller growth stage in order 

to consistently achieve commercially acceptable control. Refer to the Roundup WeatherMax label 

(U.S. EPA Reg. No. 524-537) for a listing of these weeds.

Additionally, dicamba provides effective control of herbicide-resistant broadleaf weeds, including 

glyphosate-resistant weeds such as marestail, common ragweed, giant ragweed, palmer pigweed, and 

waterhemp. Herbicide resistant weeds are those listed on the International Survey of Resistant 

Weeds website (www.weedscience.org).
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 865 of 946

DT soybean will be combined with MON 89788 (Roundup Ready 2 Yield®soybean) utilizing 

traditional breeding techniques. Dicamba is an effective broadleaf herbicide and the potential use of 

dicamba and glyphosate herbicides at the same time in mixtures for weed control will provide 

growers greater application flexibility prior to planting as well as in-crop for greater consistency of 

control in both conventional and conservation tillage situations. Use of dicamba, in addition to 

glyphosate and the other herbicide options currently labeled for use on soybean, provides more 

options to implement diversified weed management programs to control a broad spectrum of grass 

and broadleaf weed species. Successful adoption of the dicamba tolerance trait, into the Roundup 

Ready® soybean system, will provide: 1) growers with an opportunity for an efficient, effective weed 

management system; 2) an option to mitigate the potential for further resistance to glyphosate and 

other critically important soybean herbicides, in particular, herbicides in the ALS and PPO class of 

chemistry; 3) excellent crop safety, and 4) continue to provide soybean growers with effective weed 

control systems necessary for production yields to meet the growing needs of the food, feed, and 

industrial markets. The combination of dicamba and glyphosate tolerance in soybeans will also 

provide the basis for mitigating the potential for the evolution of further weed resistance to 

glyphosate, dicamba, and herbicides in general, because of the ability to use these two modes of 

action in mixtures and sequences. 

DT soybean contains a gene from Stenotrophomonas maltophilia that expresses a mono-oxygenase 

enzyme that rapidly demethylates dicamba rendering it inactive, thereby conferring tolerance to 

dicamba. The demethylation of dicamba produces 3,6-dichlorosalicylic acid (DCSA), a known 

soybean, soil, and livestock metabolite whose safety has been evaluated by the Environmental 

Protection Agency (U.S. EPA). DCSA, in addition to dicamba, is included in the current 10 ppm 

pesticide residue tolerance for soybean seed that supports the existing uses of dicamba on 

commercial soybean (40 CFR § 180.227). Even with the expanded use of dicamba on DT soybean, 

compared to commercial soybean uses, the rapid metabolism of dicamba results in residues in 

dicamba-treated DT soybean seed, including the DCSA metabolite, that are well below the 

established 10 ppm tolerance, and therefore no modification to the existing soybean seed tolerance 

is needed. Consequently, only approval for the expanded use pattern of dicamba on DT soybean 

has been requested of EPA. 

G.2.2. Data and Information Presented Confirm the Lack of Plant Pest Potential of DT 

soybean Compared to Conventional Soybean

The data and information presented in petition #10-188-01p demonstrate DT soybean is 

agronomically, phenotypically, and compositionally comparable to conventional soybean with the 

exception of its tolerance to dicamba. Moreover, the data presented demonstrate DT soybean is 

unlikely to pose an increased plant pest risk, including weediness or adverse environmental impact, 

compared to conventional soybean. The food, feed, and environmental safety of DT soybean was 

confirmed based on multiple, well-established lines of evidence:

 

® Roundup Ready 2 Yield and Roundup Ready are registered trademarks of Monsanto Technology LLC.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 866 of 946

1. Soybean is a familiar crop that does not possess any of the attributes commonly associated 

with weeds and has a history of safe consumption.

2. A detailed molecular characterization of the inserted DNA demonstrated a single, intact 

copy of the T-DNA insert in a single locus within the soybean genome.

3. Data confirmed that the dicamba mono-oxygenase (DMO) in DT soybean (MON 87708 

DMO) is unlikely to be a toxin or allergen based on extensive information collected.

4. A compositional assessment of seed and forage confirmed that DT soybean is 

compositionally equivalent to conventional soybean.

5. An extensive evaluation on phenotypic and agronomic characteristics and environmental 

interactions of DT soybean demonstrated no increased plant pest potential compared to 

conventional soybean.

6. An assessment of potential impact on non-target organisms (NTOs) and endangered species 

indicated that, under normal agricultural conditions, DT soybean is unlikely to have adverse 

effects on these organisms compared to conventional soybean.

7. Evaluation of DT soybean using current cultivation and management practices for soybean 

concluded that deregulation of DT soybean will not significantly impact soybean agronomic 

practices or land use, with the exception of the expanded window of dicamba application. 

G.2.3. Soybean is a Familiar Crop Lacking Weedy Characteristics 

There is a longstanding history of safe use and consumption of conventional soybean and processed 

products. Soybean is grown as a commercial crop in over 35 countries. Domestication occurred as 

early as 1000 B.C. and soybean is now the most widely grown oilseed crop in the world, with 

approximately 211 million metric tons of harvested seed produced in 2008, which represented 56% 

of world oilseed seed production that year. 

The commercial soybean species in the U.S. (Glycine max L. Merr.) does not exhibit weedy 

characteristics, does not invade established ecosystems, and does not outcross to weedy relatives. 

Soybean is not listed as a weed in major weed references, nor is it present on the lists of noxious 

weed species distributed by the federal government (7 CFR Part 360). During 2004 to 2008, U.S. 

growers planted between 64.7 and 75.7 million acres of soybean. Soybean does not possess any of 

the attributes commonly associated with weeds, such as long persistence of the seed in the soil, 

ability to disperse, invade, or become a dominant species in new or diverse landscapes, or the ability 

to compete well with native vegetation. However, due to a pronounced lack of dormancy it is 

known that soybean seed can germinate quickly under adequate temperature and moisture 

conditions, and can potentially grow as a volunteer plant. However, a volunteer soybean plant likely 

would be killed by frost during the autumn or winter of the year it germinated. Furthermore, if a 

volunteer plant were to survive, it would not compete well with the succeeding crop, and would be 

controlled readily via mechanical or other chemical means. Twenty commonly used agricultural 

herbicides, representing eight modes-of-action (i.e., ALS-inhibitor, chloroacetamide, EPSPS, PPO 

inhibitor, PSI disruption, PSII inhibitor, synthetic auxin, and tubulin inhibitor classes) were tested as 

DT soybean potential substrates for MON 87708 DMO. Other than dicamba, none of the 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 867 of 946

herbicides tested were found to affect the tolerance of DT soybean at commercial application rates, 

therefore, herbicides effective for control of volunteer soybean can still be used to control DT 

soybean volunteers. Finally, since wild populations of Glycine species are not known to exist in the 

U.S., there is no potential for DT soybean to outcross to wild or weedy relatives.

G.2.4. Conventional Soybean A3525 is an Appropriate Comparator to DT Soybean

Soybean variety A3525 is the near isogenic line to DT soybean and was used as the conventional 

soybean comparator to support the safety assessment of DT soybean. DT soybean and the near 

isogenic conventional soybean control A3525 have similar genetic backgrounds with the exception 

of the dmo expression cassette, thus, the effect of the dmo expression cassette and the expressed 

MON 87708 DMO could be assessed in an unbiased manner. 

G.2.5. Molecular Characterization Verifies the Integrity and Stability of the Inserted 

DNA in DT Soybean

MON 87708 was developed through Agrobacterium-mediated transformation of conventional

soybean A3525 meristem tissue with the 2T-DNA plasmid vector PV-GMHT4355. 

PV-GMHT4355 contains two separate T-DNAs that are each delineated by Left and Right Border 

sequences. The first T-DNA, designated as T-DNA I, contains the dmo expression cassette 

regulated by the peanut chlorotic streak virus (PC1SV) promoter and the pea E9 3′ non-translated 

region. The second T-DNA, designated as T-DNA II, contains the cp4 epsps expression cassette 

under the regulation of the figwort mosaic virus (FMV) promoter and the pea E9 3′ non-translated 

region. During transformation, both T-DNAs were inserted into the soybean genome, where 

T-DNA II, containing the cp4 epsps expression cassette, functioned as a marker gene for the selection 

of transformed plantlets. Subsequently, conventional self-pollination breeding methods and 

segregation were used to isolate a plant containing the dmo expression cassette but not containing the 

cp4 epsps expression cassette, resulting in the production of marker-free, dicamba-tolerant soybean 

MON 87708. 

Molecular characterization by Southern blot analyses determined that DT soybean contains one 

copy of the T-DNA I at a single integration locus and all expression elements are present. These 

data also demonstrated that DT soybean does not contain detectable backbone sequences from the 

plasmid vector or T-DNA II sequences. The complete DNA sequence of the insert and adjacent 

genomic DNA sequence in DT soybean confirmed the integrity of the inserted dmo expression 

cassette within the inserted sequences and identified the 5′ and 3′ insert-to-genomic DNA junctions. 

Furthermore, Southern blot analysis demonstrated that the insert in DT soybean has been 

maintained through at least five generations of breeding, thereby confirming the stability of the 

insert over multiple generations. 

G.2.6. Data Confirm DT Soybean DMO Safety

DT soybean contains a dmo expression cassette that results in two forms of the DMO protein; 

referred to as DMO and DMO+27 (See Appendix I.). The active form of these proteins, necessary 

to confer dicamba tolerance, is a trimer comprised of three DMO monomers. In DT soybean, the 

trimer can be comprised of DMO, DMO+27, or a combination of both. Therefore, this document 

will refer to both forms of the protein and all forms of the trimer as MON 87708 DMO. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 868 of 946

A multistep approach was used to characterize MON 87708 DMO. This detailed characterization 

and assessment confirmed that MON 87708 DMO is safe for human and animal consumption. The 

assessment involved: 1) characterization of the physicochemical and functional properties of 

MON 87708 DMO; 2) quantification of MON 87708 DMO levels in plant tissues; 3) comparison of 

the amino acid sequence of MON 87708 DMO to known allergens, gliadins, glutenins, toxins, and 

other biologically active proteins known to have adverse effects on mammals; 4) evaluation of the 

digestibility of MON 87708 DMO in simulated gastric and intestinal fluids; 5) endogenous and 

exogenous substrate specificity of DMO; 6) documentation of the history of safe consumption of 

mono-oxygenases (the class of enzymes to which MON 87708 DMO belongs); and 7) investigation 

of the potential mammalian toxicity through an oral gavage assay. 

DMO was found to be specific to dicamba when tested using structurally similar endogenous 

substrates and exogenous herbicide substrates representing a wide range of modes-of-action. 

MON 87708 DMO has no relevant amino acid sequence similarities with known allergens, gliadins, 

glutenins, toxins, and other biologically active proteins that may have adverse effects on mammals. 

MON 87708 DMO was rapidly degraded in simulated gastric and intestinal fluids and a high dose of 

this protein in a mouse acute oral toxicity evaluation demonstrated that it is not acutely toxic, and 

does not cause any adverse effect. The safety assessment supports the conclusion that exposure to 

MON 87708 DMO poses no meaningful risk to the environment, or human and animal health. 

G.2.7. DT Soybean is Compositionally Equivalent to Conventional Soybean

Detailed compositional analyses in accordance with OECD guidelines were conducted to assess 

whether levels of key nutrients and anti-nutrients in DT soybean were comparable to levels present 

in the aforementioned near isogenic conventional soybean control A3525 and several commercial

reference soybean varieties. Seed and forage were harvested from five individual sites in which DT 

soybean (both treated with dicamba herbicide at the V2-V3 growth stage and not treated with 

dicamba herbicide), the conventional control, and a range of commercial reference varieties were 

grown concurrently in the same field trial. The commercial reference varieties used to establish a 

range of natural variability for the key nutrients and anti-nutrients in commercial soybean varieties 

have a history of safe consumption. Nutrients assessed in this analysis included proximates (ash, 

carbohydrates by calculation, moisture, protein, and fat), fiber, amino acids (18 components), fatty 

acids (FA, C8-C22), and vitamin E (α-tochopherol) in seed, and proximates (ash, carbohydrates by 

calculation, moisture, protein, and fat) and fiber in forage. The anti-nutrients assessed in seed 

included raffinose, stachyose, lectin, phytic acid, trypsin inhibitors, and isoflavones (daidzein, 

genistein, and glycitein).

The combined-site analysis was conducted to determine statistically significant differences (5% level 

of significance) between DT soybean and the near isogenic conventional control A3525. The results 

from the combined-site data were reviewed using considerations relevant to food and feed safety 

and nutritional quality. These considerations included assessments of: 1) the relative magnitudes of 

the difference in the mean values of nutrient and anti-nutrient components of DT soybean and the 

conventional control, 2) whether the DT soybean component mean value was within the range of 

natural variability of that component as represented by the 99% tolerance interval of the commercial 

reference varieties grown concurrently in the same field trial, 3) analyses of the reproducibility of the 

statistically significant combined-site component differences at individual sites, and 4) assessing the 

differences within the context of natural variability of commercial soybean composition published in 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 869 of 946

the scientific literature and in the International Life Sciences Institute (ILSI) Crop Composition 

Database.

Assessment of the analytical results confirmed that the differences observed in the combined-site 

analysis were not meaningful to food and feed safety or the nutritional quality of DT soybean 

soybean. In addition, the levels of assessed components in DT soybean were compositionally 

equivalent to the conventional control and within the range of variability of the commercial 

reference varieties that were grown concurrently in the same field trial.

G.2.8. DT Soybean Does Not Change Soybean Plant Pest Potential or Environmental 

Interactions

“Familiarity” is an important consideration in assessing the plant pest potential of a biotechnologyderived crop. Conceptually, “familiarity” is based upon the fact that the new biotechnology-derived 

plant is developed from a conventional plant variety whose biological properties and plant pest 

potential are well known. Familiarity considers the biology of the plant, the introduced trait, the 

receiving environment, and the interactions among these factors that provides a basis for 

comparative risk assessment between a biotechnology-derived plant and the conventional control. 

Following this concept, the phenotypic, agronomic, and environmental interaction assessment of 

DT soybean included the near isogenic conventional soybean control A3525 and the commercial 

reference varieties. Characteristics assessed included: seed dormancy and germination, pollen 

morphology, and symbiont interactions conducted in the laboratory and greenhouse; and plant 

phenotypic and agronomic evaluations and environmental interaction observations conducted in the 

field. The commercial soybean reference varieties grown concurrently were used to establish a range 

of natural variability for each assessed characteristic in soybean. The phenotypic, agronomic, and 

environmental interaction assessment demonstrated that DT soybean is equivalent to the 

conventional control. Thus, DT soybean is unlikely to have a changed plant pest potential 

compared to conventional soybean. 

Seed dormancy and germination characterization demonstrated that DT soybean seed had 

germination characteristics similar to seed of the conventional control. In particular, the lack of 

hard seed, a well-accepted characteristic of weediness affecting seed germination, supports a 

conclusion of no increased weediness of DT soybean when compared to the conventional control. 

For pollen characteristics and symbiont interactions, there were no statistically significant differences 

(5% level of significance) observed between DT soybean and the conventional control for any of the 

parameters measured, including pollen viability and diameter, nodule number and dry weight, shoot 

total nitrogen, and shoot and root dry weight. Collectively, these results support the conclusion that 

DT soybean is not likely to exhibit increased plant pest potential compared to conventional soybean.

The field evaluation of phenotypic, agronomic, and environmental interaction characteristics of DT 

soybean also support the conclusion that DT soybean is not likely to have an increased plant pest 

potential compared to conventional soybean. The evaluations were conducted at 18 replicated field 

sites across North American soybean production regions. These assessments included plant growth 

and development characteristics, as well as observations for plant responses to abiotic stressors and 

plant-disease and plant-arthropod interactions. The observed phenotypic characteristics were similar 

between DT soybean and the conventional control. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 870 of 946

In a combined-site analysis, data show no statistically significant differences (5% level of 

significance) between DT soybean and the conventional control for early stand count, seedling 

vigor, days to 50% flowering, lodging, pod shattering, final stand count, seed moisture, seed test 

weight, or yield. Two statistically significant differences were detected between DT soybean and the 

conventional control for plant height and 100 seed weight. DT soybean was slightly taller and had a 

lower 100 seed weight than the conventional control. However, both differences were small in 

magnitude. Additionally, DT soybean and the conventional control were within the same range of 

plant growth stages for 131 out of the 132 growth stage observations among the sites. Except for 

the differences in plant height, 100 seed weight, and a single growth stage observation at one site, all 

values for DT soybean fell within the range of the commercial reference varieties grown 

concurrently. None of these differences were considered biologically meaningful in terms of 

increased plant pest potential of DT soybean compared to conventional soybean.

In an individual-site assessment of abiotic stress response and disease damage, no differences were 

observed between DT soybean and the conventional control for 193 out of 194 comparisons for the 

assessed abiotic stressors or for any of the 215 comparisons for the assessed diseases among all 

observations at the 18 sites. One difference was observed between DT soybean and the 

conventional control for wind damage during a single observation at one site. The damage rating 

for v (slight damage) was outside the range of the commercial reference varieties (no damage); 

however, the difference was not observed during any of the other 29 wind damage observations 

among the sites. Thus, the slight difference in wind damage rating was not indicative of a consistent 

plant response associated with DT soybean and is not considered biologically meaningful in terms of 

increased plant pest potential or an altered environmental impact from DT soybean compared to 

conventional soybean.

In an assessment of arthropod-related damage, no statistically significant differences (5% level of 

significance) were detected between DT soybean and the conventional control for 89 out of 95 

comparisons for the assessed arthropods. Lack of variability in the data precluded statistical 

comparisons between DT soybean and the conventional control for 121 additional comparisons; 

however, the means for DT soybean and the conventional control were the same value for these 

comparisons, indicating no biological differences. For each of the six statistically significant 

differences between DT soybean and the conventional control, the severity of arthropod-related 

damage to DT soybean was within or slightly outside the range of the commercial reference 

varieties. The differences between DT soybean and the conventional control were small in 

magnitude and were not consistent across observations or sites. Thus, the differences in arthropodrelated damage are not indicative of a consistent plant response associated with DT soybean and are 

not considered biologically meaningful in terms of increased plant pest potential or an altered 

environmental impact from DT soybean compared to conventional soybean.

In an assessment of pest and beneficial arthropod abundance, no statistically significant differences 

(5% level of significance) were detected between DT soybean and the conventional control for 142 

out of 151 comparisons (including 74 arthropod pest and 77 beneficial arthropod comparisons) 

among the multiple collections conducted during the season at four sites. For the nine detected 

differences in arthropod abundance, seven were arthropod pests (green cloverworm, Japanese 

beetles, and stink bugs) and two were beneficial arthropods (spiders and Nabis spp). The differences 

detected in pest and beneficial arthropod abundance were small in magnitude and were not 

consistent with other collection times at the individual sites or across the sites. Consequently, it is 

concluded that the differences in pest and beneficial arthropod abundance are not indicative of a 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 871 of 946

consistent plant response associated with DT soybean and are not biologically meaningful in terms 

of increased plant pest potential or an altered environmental impact from DT soybean compared to 

conventional soybean.

Field evaluations of phenotypic, agronomic, and environmental interaction characteristics of DT 

soybean treated with dicamba herbicide were also conducted. Data were collected from field trials 

conducted at eight sites within the U.S. soybean producing regions. These assessments included 

plant growth and development characteristics, as well as observations for plant responses to abiotic 

stressors, plant-disease and plant-arthropod interactions. The phenotypic, agronomic, and 

environmental interaction assessment demonstrated that treated DT soybean is equivalent to the 

conventional control. Thus, DT soybean is unlikely to have an altered plant pest potential compared 

to conventional soybean. 

The observed phenotypic characteristics were similar between the dicamba-treated DT soybean and 

the conventional control. In a combined-site assessment, no statistically significant differences were 

detected between treated DT soybean and the conventional control for early stand count, seedling 

vigor, days to 50% flowering, plant height, lodging, pod shattering, final stand count, seed moisture, 

or yield. One statistically significant difference was detected between treated DT soybean and the 

control, for 100 seed weight. The difference in 100 seed weight was relatively small in magnitude 

and the mean 100 seed weight of treated DT soybean was slightly below the reference range. It is 

unlikely that this small difference in 100 seed weight would contribute to increased weed potential of 

DT soybean when treated with dicamba compared to conventional soybean. Additionally, treated 

DT soybean and the control were within the same range of plant growth stages for all growth stage 

observations among the sites. None of these differences were considered biologically meaningful in 

terms of increased plant pest potential of treated DT soybean compared to conventional soybean.

In an assessment of plant response to abiotic stressors and disease damage, no differences were 

observed between treated DT soybean and the conventional control for 181 of 182 comparisons 

among all observations at the eight sites. One difference was observed between treated DT soybean

and the control for white mold during a single observation (slight vs. none). The damage rating for 

treated DT soybean was outside of the reference range (no damage was observed in the references). 

This difference was not observed in any of the other two white mold evaluations across the sites and 

is not considered biologically meaningful in terms of increased plant pest potential or an altered 

environmental impact from treated DT soybean compared to conventional soybean.

In an assessment of arthropod-related damage, there were no statistically significant differences 

detected between treated DT soybean and the control for 56 out of 59 comparisons. Lack of 

variability in the data precluded statistical comparisons between treated DT soybean and the 

conventional control for 34 additional comparisons. The mean damage ratings for bean leaf beetle 

and grasshopper damage was outside the reference range however the response was not consistent 

across observations or sites. Thus, the results are not considered biologically meaningful in terms of 

adverse environmental impacts of treated DT soybean compared to the conventional soybean.

In summary, the phenotypic, agronomic, and environmental interaction data were collected to 

provide a detailed characterization of DT soybean and to assess whether the introduction of the 

dicamba tolerance trait in DT soybean and the associated application of dicamba herbicide alters the 

plant pest potential compared to conventional soybean. The analysis considered the comparisons of 

DT soybean to the conventional control, the reproducibility, magnitude, and direction of detected 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 872 of 946

differences (trends), and comparison to the range of the commercial reference varieties. Results 

from the phenotypic, agronomic, and environmental interactions assessment indicated that DT 

soybean does not possess weedy characteristics, increased susceptibility or tolerance to specific 

abiotic stress, diseases, or arthropods, or characteristics that would confer a plant pest risk or a 

significant environmental impact compared to conventional soybean.

G.2.9. DT Soybean Will Not Adversely Affect NTOs or Threatened and Endangered 

Species

Evaluation of the impacts of a biotechnology-derived crop on Non-Target Organisms (NTOs) and 

threatened and endangered species is a component of the plant pest risk assessment. Since DT 

soybean does not possess pesticidal activity, all organisms that interact with DT soybean are 

considered to be NTOs. The environmental assessment demonstrated that the presence of the 

dicamba tolerance trait in DT soybean and the associated application of dicamba did not alter plantarthropod interactions, including beneficial arthropods, or alter disease susceptibility compared to 

the conventional control. 

The biochemical information and experimental data for evaluation of DT soybean included 

molecular characterization, MON 87708 DMO safety assessments, the history of environmental 

exposure to mono-oxygenases (the class of enzymes to which MON 87708 DMO belongs), 

information from the environmental interaction assessment, demonstration of compositional 

equivalence to conventional soybean, and demonstration of agronomic and phenotypic equivalence 

to conventional soybean. Taken together, these data support the conclusion that DT soybean has 

no reasonable mechanism for harm to NTOs, or to pose an additional risk to threatened and 

endangered species compared to the cultivation of conventional soybean.

The potential for outcrossing and gene introgression from DT soybean to sexually-compatible 

species in the U.S. is unlikely since no known wild Glycine species related to cultivated soybean are 

known to be present in North America. Furthermore, should cross-pollination occur, DT soybean 

and its progeny are not expected to exhibit a significant environmental impact because, as described 

above, evaluations have shown that the presence of the dicamba tolerance trait is not likely to 

enhance weediness or plant-pest potential. Therefore, the environmental consequence of pollen 

transfer from DT soybean to other Glycine species is considered negligible. 

G.2.10.Deregulation of DT Soybean Will Not Significantly Impact Soybean Agronomic 

Practices or Land Use

Soybean fields are typically highly managed agricultural areas that are dedicated to crop production 

for many years. Cultivation of DT soybean would not be expected to differ from typical soybean 

cultivation, with the sole exception of an expanded window of dicamba applications due to the 

presence of the dicamba tolerance trait in DT soybean. DT soybean likely would be used in 

common rotations on land currently used for agricultural purposes. As demonstrated, DT soybean 

is similar to conventional soybean in its agronomic, phenotypic, ecological, and compositional 

characteristics and has comparable levels of resistance to insects and diseases as compared to 

commercial soybean. Therefore, the introduction of DT soybean into the Roundup Ready soybean 

system is not expected to have a significant impact on current cultivation and management practices 

for soybean. The adoption of DT soybean into the Roundup Ready soybean system will provide 

growers with another herbicide mode-of-action and the means to control broadleaf weeds, including 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 873 of 946

hard-to-control and herbicide-resistant broadleaf weeds, and will help preserve conservation tillage 

practices by providing growers with an additional weed management tool. Based on these 

considerations, there is no apparent potential for significant impacts on agronomic practices or land 

use, with the exception of the expanded application window of dicamba. 

G.2.11.Conclusion

Based on the data and information presented in petition #10-188-01p, it is concluded that DT 

soybean is not likely to be a plant pest. Therefore, Monsanto Company requests a determination 

from APHIS that DT soybean and any progeny derived from crosses between DT soybean and 

conventional soybean or previously deregulated biotechnology-derived soybean, be granted 

nonregulated status under 7 CFR Part 340.

G.3. Dicamba and Glufosinate-Tolerant Cotton (DGT Cotton)

G.3.1. Product Description

Monsanto Company has developed dicamba and glufosinate-tolerant cotton, MON 88701, which 

will allow in-crop applications of dicamba herbicide for the control of broadleaf weeds from 

preemergence to seven days preharvest and glufosinate herbicide for broad spectrum weed control 

from emergence through early bloom growth stage. DGT cotton provides a wider dicamba window 

of application beyond the current preplant cotton uses and glufosinate application rates and timings 

that are equivalent to current commercial glufosinate-tolerant cotton. The combination of these two 

unique herbicide modes-of-action provides an effective weed management system for cotton 

production. Dicamba provides effective control of over 95 annual and biennial weed species, and 

suppression of over 100 perennial broadleaf and woody plant species. Glufosinate, a broadspectrum contact herbicide, provides nonselective control of approximately 120 broadleaf and grass 

weeds. Additionally, dicamba and glufosinate provide control of herbicide-resistant weeds, including 

glyphosate-resistant biotypes of Palmer amaranth (Amaranthus palmeri), marestail (Conyza canadensis), 

common ragweed (Ambrosia artemisiifolia), giant ragweed (Ambrosia trifida) and waterhemp 

(Amaranthus tuberculatus).

DGT cotton contains a demethylase gene from Stenotrophomonas maltophilia that expresses a dicamba 

mono-oxygenase (DMO) protein to confer tolerance to dicamba herbicide. DMO protein rapidly 

demethylates dicamba to the herbicidally inactive metabolite 3,6-dichlorosalicylic acid (DCSA). 

DCSA has been previously identified as a metabolite of dicamba in cotton, soybean, livestock, and 

soil. Monsanto will request a registration from U.S. EPA for the expanded use of dicamba on DGT 

cotton, an increase in the dicamba residue tolerance for cottonseed, the establishment of a tolerance 

for cotton gin by-products, and the inclusion of DCSA in the residue definitions for both 

cottonseed and gin by-products. No other revisions to the dicamba pesticide residue tolerances are 

necessary including animal products such as meat, eggs, and milk. Furthermore, the use of dicamba 

on DGT cotton does not present any new environmental exposure scenarios not previously 

evaluated and deemed acceptable by U.S. EPA.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 874 of 946

DGT cotton also contains a bialaphos resistance (bar) gene from Streptomyces hygroscopicus that 

expresses the phosphinothricin N-acetyltransferase (PAT) protein to confer tolerance to glufosinate 

herbicide. PAT (bar)

246 protein acetylates the free amino group of glufosinate to produce nonherbicidal N-acetyl glufosinate, a well known metabolite in glufosinate-tolerant plants. The use 

pattern and rate of glufosinate on DGT cotton will follow the existing glufosinate-tolerant cotton 

uses outlined on the glufosinate herbicide label. The glufosinate residues in DGT cotton treated 

with commercial glufosinate rates are below the established pesticide residue tolerances for both 

cottonseed and gin by-products. Therefore, Monsanto will not seek any changes in the glufosinate 

label or the established tolerances for its use on DGT cotton.

DGT cotton will be combined, through traditional breeding methods, with other deregulated 

herbicide-tolerant (e.g., glyphosate-tolerant) events. The in-crop use of dicamba and glufosinate 

herbicides, in addition to glyphosate herbicide, provides improved weed management options in 

cotton to control a broad spectrum of grass and broadleaf weed species and effective control of 

weeds resistant to several herbicide families. Successful integration of DGT cotton into glyphosatetolerant cotton systems will provide: 1) an opportunity for an efficient, effective weed management 

system for hard-to-control and herbicide-resistant weeds; 2) a flexible system for two additional 

herbicide modes-of-action for in-crop application in current cotton production systems as 

recommended by weed science experts to manage future weed resistance development; 3) an option 

to mitigate the potential for development of further resistance to glyphosate and other critically 

important cotton herbicides; in particular, herbicides in the acetolactate synthase inhibitor (ALS) and 

protoporphyrinogen oxidase inhibitor (PPO) class of chemistry; 4) crop safety to dicamba, 

glufosinate, and glyphosate; and 5) additional weed management tools to enhance weed 

management systems necessary to maintain yield and quality to meet the growing needs of the food, 

feed, and industrial markets.

G.3.2. Data and Information Presented Confirms the Lack of Plant Pest Potential and 

the Food and Feed Safety of DGT Cotton Compared to Conventional Cotton

The data and information presented in petition #12-185-01p demonstrate MON 88701 is 

agronomically, phenotypically, and compositionally comparable to commercially cultivated cotton, 

with the exception of its tolerances to both dicamba and glufosinate. Moreover, the data presented 

demonstrate DGT cotton is unlikely to pose an increased plant pest risk, including weediness, or 

adverse environmental impact, compared to commercially cultivated cotton. The food, feed, and 

environmental safety of DGT cotton was confirmed based on multiple, well-established lines of 

evidence:

 

246 PAT (bar) indicates the PAT protein encoded by the bar gene isolated from S. hygroscopicus. The pat gene from S. viridochromogenes

also encodes a PAT protein that confers glufosinate tolerance. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 875 of 946

 Cotton is a familiar crop that does not possess any of the attributes commonly associated 

with weeds, and has a history of safe usage and consumption.

 A detailed molecular characterization of the inserted DNA demonstrated a single, intact 

copy of the T-DNA insert in a single locus within the cotton genome.

 Extensive evaluation of the proteins expressed in DGT cotton, dicamba mono-oxygenase 

(MON 88701 DMO) and phosphinothricin acetyltransferase [PAT (bar)], confirmed they are 

unlikely to be toxins or allergens. In addition, PAT proteins are in several other 

commercially-available crops that have been reviewed and previously deregulated by USDA, 

including those in cotton, corn, soy, canola, sugarbeet, and rice.

 A compositional assessment of cottonseed confirmed that DGT cotton is compositionally 

equivalent to commercially cultivated cotton.

 An extensive evaluation of phenotypic, agronomic, and plant mapping characteristics, as well 

as environmental interactions of DGT cotton, demonstrated no increased plant pest 

potential compared to commercially cultivated cotton.

 An assessment of potential impact on non-target organisms (NTOs) indicated that, under 

anticipated agricultural conditions, DGT cotton is unlikely to have adverse effects on these 

organisms compared to commercially cultivated cotton.

 Evaluation of DGT cotton using current agronomic management practices for cotton 

concluded that deregulation of DGT cotton is not likely to impact cotton agronomic 

practices or land use, with the exception of the expanded window of dicamba application. 

G.3.3. Cotton is a Familiar Crop Lacking Weedy Characteristics 

Cotton, as a commodity crop, has a longstanding history of cultivation; its by-products, including 

processed fractions, also have a history of safe use and consumption. Cotton is grown in 17 states 

across the southern U.S. and in over 80 countries world-wide. In 2011, U.S. growers planted 

approximately 14.7 million acres of cotton. 

The commercial cotton species in the U.S. (Gossypium hirsutum and Gossypium barbadense L. Merr.) do 

not exhibit weedy characteristics as defined by USDA, and neither invade established ecosystems, 

nor outcross to weedy relatives. Cotton is not listed as a weed in major weed references, nor is it 

present on the lists of noxious weed species distributed by the federal government (7 CFR Part 360). 

Cotton does not possess any of the attributes commonly associated with weeds, such as long 

persistence of the seed in the soil, ability to disperse, invade, or become a dominant species in new 

or diverse landscapes, or the ability to compete well with native vegetation. It is recognized that in 

some agricultural systems, cotton can volunteer in a subsequent rotational crop. However, 

volunteers are easily controlled through tillage or the use of appropriate herbicides with diverse 

modes-of-action (e.g., ALS inhibitor, chloroacetamide, EPSPS, PPO inhibitor, PSI disruption, PSII 

inhibitor, synthetic auxin, and tubulin inhibitor classes). Specificity studies using the aforementioned 

herbicides as potential substrates for MON 88701 DMO showed similar injury levels for DGT 

cotton compared to the conventional control, indicating that these herbicides do not serve as a 
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substrate for MON 88701 DMO at commercial application rates. Additionally, the specificity of 

PAT (bar) has been established in the published scientific literature. Therefore, herbicides effective 

for control of volunteer conventional cotton can still be used to control DGT cotton volunteers.

In the continental U.S., wild populations of Gossypium species and some feral populations of 

cultivated variants of G. hirsutum exist, but these species, which are able to cross with cultivated 

cotton, are not known to exist in cotton growing areas. Importantly, DGT cotton would not be 

expected to confer a selective advantage to, or enhance the pest potential of, progeny resulting from 

such a cross if it were to occur, and could easily be controlled through current agronomic practices 

used to control conventional cotton. Thus, with environmental and biological limitations and 

varying chemical and agronomic practices available in the areas with wild and/or feral populations, 

there is limited probability for DGT cotton or any Gossypium species to outcross with wild or feral 

plants.

G.3.4. Conventional Cotton Coker 130 is an Appropriate Comparator to DGT Cotton

Cotton variety Coker 130 is the near isogenic line to DGT cotton and was used as the conventional 

cotton comparator to support the safety assessment of DGT cotton. DGT cotton and the near 

isogenic conventional cotton control Coker 130 have similar genetic backgrounds with the exception 

of the dmo and bar expression cassettes; thus, the effect of the dmo and bar expression cassettes and 

the expressed MON 88701 DMO and PAT (bar) proteins could be evaluated. 

G.3.5. Molecular Characterization Verified the Integrity and Stability of the Inserted 

DNA in DGT Cotton

DGT cotton was developed through Agrobacterium-mediated transformation of hypocotyls from 

cotton variety Coker 130 utilizing vector PV-GHHT6997. PV-GHHT6997 contains one T-DNA 

that is delineated by Left and Right Border regions. The T-DNA contains the dmo and bar

expression cassettes. The dmo expression cassette is regulated by the PC1SV promoter, the TEV 5′ 

leader sequence, and the E6 3′ untranslated region. The chloroplast transit peptide CTP2 directs 

transport of the MON 88701 DMO protein to the chloroplast and is derived from CTP2 target 

sequence of the Arabidopsis thaliana shkG gene. The bar expression cassette is regulated by the e35S

promoter, the Hsp70 leader, and the nos 3′ untranslated region. After transformation, self pollination 

and segregation were used to select those plants containing a single homozygous copy of the TDNA, including both the dmo and bar expression cassettes, resulting in the selection of DGT cotton.

Molecular characterization determined that DGT cotton contains one copy of the T-DNA at a 

single integration locus and all genetic elements are present. These data also demonstrated that 

DGT cotton does not contain detectable backbone sequences from the plasmid vector. The 

complete DNA sequence of the insert and adjacent genomic DNA sequences in DGT cotton 

confirmed the integrity of the inserted dmo and bar expression cassettes and identified the 5′ and 3′ 

insert to flank DNA junctions. Molecular characterization analysis also demonstrated that the insert 

in DGT cotton has been maintained over five consecutive generations of breeding, thereby 

confirming the stability of the insert. Furthermore, results from segregation analyses show 
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inheritance and stability of the insert were as expected across multiple generations, which 

corroborates the molecular insert stability analysis determination that the DGT cotton T-DNA 

resides at a single chromosomal locus within the cotton genome. 

G.3.6. Data Confirms MON 88701 DMO and PAT (bar) Protein Safety

A multistep approach was used to characterize and assess the safety of the MON 88701 

DMO and PAT (bar) proteins expressed in DGT cotton resulting from the genetic modification. 

The expression levels of the MON 88701 DMO and PAT (bar) proteins in selected tissues of DGT 

cotton were determined. An assessment of the allergenic potential of the MON 88701 DMO and 

PAT (bar) proteins supports the conclusion that neither protein poses a significant allergenic risk to 

humans or animals. In addition, the donor organisms for the MON 88701 DMO and PAT (bar) 

protein coding sequences, Stenotrophomonas maltophilia and Streptomyces hygroscopicus, respectively, are 

ubiquitous in the environment and are not commonly known for human or animal pathogenicity or 

allergenicity. Bioinformatics analysis determined that the MON 88701 DMO and PAT (bar) 

proteins lack structural similarity to known allergens, gliadins, glutenins, or protein toxins. The 

MON 88701 DMO and PAT (bar) proteins are rapidly digested in simulated gastrointestinal fluids 

and neither protein demonstrates acute oral toxicity in mice at the levels tested. Hence, the 

consumption of the MON 88701 DMO and PAT (bar) proteins from DGT cotton or its progeny 

poses no meaningful risk to the environment or human and animal health. 

G.3.7. DGT Cotton is Compositionally Equivalent to Conventional Commercial Cotton

Detailed compositional analyses were conducted in accordance with OECD guidelines to 

assess whether levels of key nutrients and anti-nutrients in DGT cotton cottonseed were comparable 

to levels in the conventional control, Coker 130, and several commercial reference cotton varieties. 

These compositional comparisons were made by analyzing cottonseed harvested from eight U.S. 

field sites in which DGT cotton was treated with dicamba and glufosinate, with the conventional 

control, and a range of commercial reference varieties that were grown concurrently in the same 

field trial. Compositional comparisons of DGT cotton not treated with dicamba or glufosinate 

herbicides were also conducted to further support the assessment of DGT cotton traits. The 

commercial reference varieties used to establish a range of natural variability for key nutrients and 

anti-nutrients have a history of safe consumption. Nutrients assessed in this analysis included 

proximates (ash, carbohydrates, and calories by calculation, moisture, protein, and fat), fibers (ADF, 

crude fiber, NDF, and TDF), amino acids (18 components), fatty acids (C8-C22), minerals (calcium, 

copper, iron, magnesium, manganese, phosphorus, potassium, sodium, and zinc) and vitamin E. 

The anti-nutrients assessed in this analysis included gossypol and the cyclopropenoid fatty acids 

dihydrosterculic, malvalic, and sterculic.

Combined-site analyses were conducted to determine if there were any statistically-significant 

differences (5% level of significance) between DGT cotton and the conventional control cottonseed 

samples. Significant differences noted from the combined-site statistical comparison were assessed 

using considerations relevant to the safety and nutritional quality of DGT cotton when compared to 

the conventional control. Considerations used to assess the relevance of each combined-site 

statistically significant difference included: 1) the relative magnitude of the difference in the mean 

values of nutrient and anti-nutrient components between DGT cotton and the conventional control; 

2) whether the DGT cotton component mean value is within the range of natural variability of that 

component as represented by the 99% tolerance interval of the commercial reference varieties 
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grown concurrently in the same trial; 3) evaluation of the reproducibility of the statistical (p < 0.05) 

combined-site component differences at individual sites; and 4) an assessment of the differences 

within the context of natural variability of commercial cotton composition published in the scientific 

literature and in the International Life Sciences Institute (ILSI) Crop Composition Database.

Based on these criteria, the observed differences were not meaningful to food and feed safety or 

nutritional value, and led to the conclusion that DGT cotton is compositionally equivalent to 

commercially cultivated cotton that has a history of safe consumption. These results support the 

overall food and feed safety of DGT cotton.

G.3.8. DGT Cotton Does Not Change Cotton Plant Pest Potential or Environmental 

Interactions

Plant pest potential of a biotechnology-derived crop is assessed from the basis of familiarity that the 

USDA recognizes as an important underlying concept in risk assessment. The concept of familiarity 

is based on the fact that the biotechnology-derived plant is developed from a conventional plant 

hybrid or variety whose biological properties and plant pest potential are well known. Familiarity 

considers the biology of the plant, the introduced trait(s), the receiving environment, and the 

interactions among these factors. This provides a basis for comparative risk assessment between a 

biotechnology-derived plant and the conventional control. Thus, the phenotypic, agronomic, plant 

mapping, and environmental interaction assessment of DGT cotton included the parental 

conventional control as a comparator. This evaluation used a weight-of-evidence approach and 

considered statistical differences between DGT cotton and the conventional control with respect to 

reproducibility, magnitude, and directionality. The observations were taken on plants not treated 

with dicamba or glufosinate, in order to evaluate the impact of the introduced traits in DGT cotton. 

To further support the trait assessment, similar supplemental observations were also conducted on 

the agronomic system that includes DGT cotton treated with dicamba and glufosinate herbicides. 

Comparison to a range of commercial reference varieties established the range of natural variability 

for cotton, and provided a context from which to further evaluate any statistical differences. 

Characteristics assessed included: seed dormancy and germination, pollen morphology, plant 

phenotypic observations, plant mapping, and environmental interaction evaluations conducted in 

the field. The phenotypic, agronomic, and environmental interaction assessment demonstrated that 

DGT cotton is comparable to conventional cotton. Thus, DGT cotton is unlikely to have increased 

weediness or plant pest potential compared to commercially cultivated cotton.

Seed dormancy and germination characterization demonstrated that DGT cotton cottonseed had 

germination characteristics similar to cottonseed of the conventional control. In particular, the lack 

of hard seed, a well-accepted characteristic of weediness affecting seed germination, supports a 

conclusion of no increased weediness of DGT cotton when compared to the conventional control. 

Additionally, there were no statistically significant (5% level of significance) differences observed 

between DGT cotton and the conventional control for pollen viability and diameter, and no visual 

differences in general pollen morphology were observed. Collectively, these results support the 

conclusion that DGT cotton is not likely to exhibit increased plant pest potential compared to 

commercially cultivated cotton.

The field evaluation of phenotypic, agronomic, plant mapping, and environmental interaction 

characteristics of DGT cotton also support the conclusion that DGT cotton is not likely to have an 

increased plant pest potential compared to commercially cultivated cotton. The evaluations were 
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conducted at 26 replicated field sites across the U.S. cotton producing region. These assessments 

included plant growth and development characteristics, including cotton plant mapping evaluations 

at harvest, as well as observations for plant responses to abiotic stressors and plant-disease and 

plant-arthropod interactions. The observed phenotypic characteristics were similar between DGT 

cotton and the conventional control.

In a combined-site analysis of plant growth and development characteristics, data showed no 

statistically significant differences (5% level of significance) between DGT cotton and the 

conventional control for stand count at 14 and 30 days after planting (DAP), final stand count, 

number of nodes above white flower at one of three observations, seed cotton yield, immature seed 

per boll, weight per boll, micronaire, fiber elongation, fiber uniformity, and fiber length. The mean 

values for DGT cotton were statistically different from the conventional control for eight 

parameters in the combined-site analysis. DGT cotton had shorter plants at 30 DAP and harvest, an 

increased number of nodes above white flower at two observations, a lower seed index, increased 

seed per boll, increased mature seeds per boll, and increased fiber strength. However, the mean 

values of DGT cotton were within the range of values observed for the commercial reference 

varieties for each of the characteristics listed above. Therefore, none of these differences were 

considered biologically meaningful in terms of increased plant pest potential of DGT cotton 

compared to commercially cultivated cotton. 

Plant mapping is a process commonly used by cotton agronomists and breeders to quantify growth 

and development parameters of a cotton plant, including boll retention. Plant mapping parameters, 

which include delineation of boll position and spatial retention of bolls, are used to measure crop 

productivity and are influenced by abiotic and biotic stressors. In the combined-site analysis of 

plant mapping parameters, no statistically significant differences were detected between DGT cotton

and the conventional control for number of mainstem nodes, number of nodes to first fruiting 

branch, total number of bolls per plant, number of vegetative bolls per plant, percent retention of 

first-position bolls, and percent first-position bolls. One statistically significant difference was 

detected between DGT cotton and the conventional control in the combined-site analysis. The 

mean value for first-position bolls per plant was higher for DGT cotton than the conventional 

control. However, the mean value of the number of first-position DGT cotton bolls was within the 

range of the commercial reference varieties. Thus, DGT cotton is similar to commercially cultivated 

cotton varieties and unlikely to have increased plant pest potential, increased weediness, or an 

adverse environmental impact compared to commercially cultivated cotton.

In an individual site assessment of abiotic stress response and disease damage, no differences were 

observed between DGT cotton and the conventional control for any of the 296 comparisons for the 

assessed abiotic stressors or for any of the 299 comparisons for the assessed diseases among all 

observations at the 26 sites. In an assessment of arthropod-related damage, no differences were 

detected between DGT cotton and the conventional control for any of the 288 comparisons for the 

assessed arthropods. The lack of significant biological differences in plant responses to abiotic 

stress, disease damage, and arthropod-related damage for DGT cotton support the conclusion that 

the introduction of the dicamba and glufosinate tolerance traits are unlikely to result in increased 

plant pest potential or an altered environmental impact from DGT cotton compared to 

commercially cultivated cotton. 

In an assessment of pest- and beneficial-arthropod abundance, no statistically significant differences 

(5% level of significance) were detected between DGT cotton and the conventional control for 173 
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out of 178 comparisons (including 89 arthropod-pest and 89 beneficial-arthropod comparisons) 

among the multiple collections conducted during the season at five geographically diverse sites. For 

the five detected differences in arthropod abundance, two were arthropod pests (stink bugs and 

tarnished plant bugs) and three were beneficial arthropods (Nabis spp. and Orius spp.). The 

differences detected in pest- and beneficial-arthropod abundance were small in magnitude and were 

not consistent with other collections at the individual sites or across the sites. Consequently, it is 

concluded that the differences in pest- and beneficial-arthropod abundance are not indicative of a 

consistent plant response associated with DGT cotton and are not biologically meaningful in terms 

of increased plant pest potential or an altered environmental impact from DGT cotton compared to 

commercially cultivated cotton. 

Field evaluations of phenotypic, agronomic, and plant mapping characteristics of DGT cotton 

treated with dicamba and glufosinate herbicides were also conducted to further support the 

assessment of DGT cotton traits. Data were collected from field trials conducted at eleven sites 

within the U.S. cotton-producing region. These assessments included plant growth and 

development characteristics, as well as plant mapping evaluations at harvest. The phenotypic, 

agronomic, and plant mapping assessments demonstrated that herbicide-treated DGT cotton is not 

different than the conventional control, which further supports that DGT cotton, whether treated 

or not with dicamba and glufosinate, is unlikely to have an altered plant pest potential compared to 

commercially cultivated cotton.

In summary, the phenotypic, agronomic, plant mapping and environmental interaction data were 

evaluated to characterize DGT cotton, and to assess whether the introduction of the traits in DGT 

cotton alters the plant pest potential compared to conventional cotton. The evaluation, using a 

weight-of-evidence approach, considered the reproducibility, magnitude, and direction of detected 

differences between DGT cotton and the conventional control, and comparison to the range of the 

commercial reference varieties. Results from the phenotypic, agronomic, plant mapping, and 

environmental interactions assessment indicated that DGT cotton does not possess weedy 

characteristics, increased susceptibility or tolerance to specific abiotic stress, diseases, or arthropods, 

or characteristics that would confer a plant pest risk or a significant environmental impact compared 

to commercially cultivated cotton.

G.3.9. DGT Cotton Will Not Adversely Affect NTOs or Threatened and Endangered 

Species
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Evaluation of the impacts of a biotechnology-derived crop on non-target organisms (NTOs) is a 

component of the plant pest risk assessment. Since MON 88701 does not possess pesticidal 

activity, all organisms that interact with DGT cotton are considered to be NTOs. The 

environmental assessment demonstrated that the presence of the dicamba and glufosinate-tolerance 

traits in DGT cotton did not alter plant-arthropod interactions, including beneficial arthropods, or 

alter disease susceptibility compared to the conventional control. In addition, plant mapping data, 

which is utilized to determine crop productivity in relation to abiotic and biotic stresses affecting 

yield, demonstrated that both DGT cotton plots treated and not treated with dicamba and 

glufosinate herbicides each had only a single significant difference from the conventional control, an 

increased number of first-position bolls that was within the range of the commercial reference 

varieties. From these data it can be concluded that both DGT cotton plants treated and not treated 

with dicamba and glufosinate responded to stressors in a similar manner.

The biochemical information and experimental data for evaluation of DGT cotton included 

molecular characterization, MON 88701 DMO and PAT (bar) safety assessments, the history of 

environmental exposure to mono-oxygenases (the class of enzymes to which MON 88701 DMO 

belongs) and the PAT proteins in several commercial glufosinate-tolerant events, information from 

the environmental interaction assessment, demonstration of compositional equivalence to 

conventional cotton, and demonstration of agronomic and phenotypic equivalence to conventional 

cotton. Overall, these data support the conclusion that DGT cotton has no reasonable mechanism 

for harm to NTOs and does not pose any additional risk to NTOs compared to commercially 

cultivated cotton.

The potential for outcrossing and gene introgression from DGT cotton to sexually compatible 

species in the U.S. is unlikely, since the only known wild Gossypium species related to cultivated 

cotton do not grow in areas where cotton is cultivated, cotton pollen movement by wind is limited 

due to it is large and sticky nature, and several studies have demonstrated that cross-pollination, even 

in the presence of high pollinator activity is limited by distance. Furthermore, should crosspollination occur, DGT cotton and its progeny are not expected to exhibit a significant 

environmental impact because, as described above, evaluations have shown that the presence of the 

dicamba and glufosinate-tolerance traits are not likely to enhance weediness or plant-pest potential. 

Therefore, the environmental consequence of pollen transfer from DGT cotton to other Gossypium

species is considered negligible.

G.3.10.Deregulation of DGT Cotton is Not Likely to Impact Cotton Agronomic 

Practices or Land Use

Cotton fields are typically highly managed agricultural areas that are dedicated to crop production 

for many years. Cultivation of DGT cotton would not be expected to differ from typical cotton 

cultivation, with the sole exception of an expanded window of dicamba application, due to the 

presence of the dicamba-tolerance trait in DGT cotton. As glufosinate is already utilized within the 

U.S. cotton-growing areas, no change in agronomic practices or land use would occur with the 

cultivation of DGT cotton and the presence of the glufosinate-tolerance trait. DGT cotton likely 

would be used in common rotations on land currently used for agricultural purposes. As 

demonstrated, DGT cotton is similar to commercially cultivated cotton in its agronomic, 

phenotypic, ecological, and compositional characteristics, and has comparable levels of resistance to 

insects, diseases, and abiotic stresses as compared to commercial cotton. Therefore, the 
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introduction of DGT cotton into the existing cotton system is not expected to have a significant 

impact on current cultivation and pest management practices for cotton. The adoption of DGT 

cotton into glyphosate-tolerant cotton systems will provide growers with two additional herbicide 

modes-of-action and the means to control broadleaf weeds, including hard-to-control and herbicideresistant broadleaf weeds, and will help preserve conservation tillage practices by providing growers 

with an additional weed management tool. Based on these considerations, DGT cotton is not likely 

to impact agronomic practices or land use, with the exception of the expanded application window 

of dicamba. 

G.3.11.Conclusion

Based on the data and information presented in petition #12-185-01p, it is concluded that DGT 

cotton is not likely to be a plant pest. Therefore, Monsanto Company requests a determination 

from USDA-APHIS that DGT cotton and any progeny derived from crosses between DGT cotton 

and conventional Gossypium cotton species or deregulated biotechnology-derived cotton be granted 

nonregulated status under 7 CFR Part 340.

G.4. Adverse Consequences of Introduction

Monsanto does not know of any results or observations associated with DT soybean, DGT cotton, 

or the MON 87708 DMO, MON 88701 DMO or PAT (bar) proteins indicating that there would be 

an adverse environmental consequence from the introduction of DT soybean or DGT cotton. DT 

soybean contains DMO that confers dicamba tolerance to the soybean plant and DGT cotton 

contains DMO and PAT that confers dicamba and glufosinate tolerance to the cotton plant, 

respectively. As demonstrated by field results and laboratory tests, the only phenotypic differences 

between DT soybean and DGT cotton and their conventional counterparts are there herbicide 

tolerances.

The data and information presented in petition #10-188-01p demonstrate that DT soybean is 

unlikely to pose an increased plant pest risk or to have an adverse environmental consequence 

compared to conventional soybean. This conclusion is based on multiple lines of evidence 

developed from a detailed characterization of the product compared to conventional soybean, 

followed by risk assessment on detected differences: 1) characterization evaluations included 

molecular analyses, which confirmed the insertion of a single functional copy of the dmo expression 

cassette at a single locus within the soybean genome; 2) measurement of the MON 87708 DMO 

levels in various soybean tissues; 3) characterization of the MON 87708 DMO confirming it is not 

novel and is structurally and functionally similar to oxygenase homologs widely present in bacteria 

and plants, where a history of safe use is established; and 4) extensive characterization of the plant 

phenotype, including compositional analysis of key nutrients and antinutrients, and environmental 

interactions. Therefore, based on the lack of increased pest potential or adverse environmental 

consequences compared to conventional soybean, the risks for humans, animals, and other NTOs 

from DT soybean are negligible under the conditions of use. Additionally the introduction of DT 

soybean will not adversely impact cultivation practices or the management of weeds, diseases, and 

insects in soybean production systems, other than the use of dicamba postemergence in soybean. 

The data and information presented in petition #12-185-01p demonstrate that DGT cotton is 

unlikely to pose an increased plant pest risk or to have an adverse environmental consequence 

compared commercially cultivated cotton. This conclusion is reached based on multiple lines of 
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evidence developed from a detailed characterization of the product compared to commercially 

cultivated cotton, followed by a risk assessment on detected differences. The characterization 

evaluation included molecular analyses, which confirmed the insertion of a single functional copy of 

the dmo and bar expression cassettes at a single locus within the cotton genome. The amino acid 

sequence of the MON 88701 DMO and PAT (bar) proteins expressed in DGT cotton are identical 

to the amino acid sequences of the respective E. coli-produced proteins utilized in the protein safety 

studies supporting the safety of the proteins. Analyses of key nutrients and, anti-nutrients of DGT 

cotton seed demonstrate that DGT cotton is compositionally equivalent to commercially cultivated 

cotton. The phenotypic evaluations of DGT cotton, including an assessment of seed germination 

and dormancy characteristics, plant growth and development characteristics, plant mapping 

parameters, pollen characteristics, and environmental interactions also indicated that DGT cotton is 

no more weedy than commercially cultivated cotton. There is no indication that DGT cotton would 

have an adverse impact on beneficial or non-target organisms. Therefore, based on the lack of 

increased plant pest potential or adverse environmental consequences compared to commercially 

cultivated cotton, the risks for humans, animals, and other NTOs from introducing DGT cotton are 

negligible under the conditions of use.

Successful integration of DT soybean and DGT cotton into the glyphosate-tolerant soybean and 

cotton systems will provide growers with an opportunity for an efficient, effective weed 

management system for the management of glyphosate’s hard-to-control and resistant broadleaf 

weeds; provide flexible systems for inclusion of a second and/or third herbicide mode-of-action in 

soybean and/or cotton production practices as recommended by weed science experts to manage 

weed resistance development; and continue to provide soybean and cotton growers with effective 

weed control systems necessary for production yields to meet the growing needs of the food, feed, 

and industrial markets.
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APPENDIX H: PRESENCE OF DICAMBA-TOLERANT SOYBEAN AND DICAMBAAND-GLUFOSINATE-TOLERANT COTTON IN HUMAN FOOD OR ANIMAL FEED
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Table of Contents

H.1. Dicamba-Tolerant Soybean ............................................................................................................888

H.1.1. Introduction ........................................................................................................................888

H.1.1.1. Soy Biology and Usage ...........................................................................888

H.1.1.2. Conventional Soy Crop ..........................................................................889

H.1.1.3. Gene and Gene Product.........................................................................889

H.1.1.4. Herbicides.................................................................................................890

H.1.2. Dicamba-Tolerant Soy Hazard Identification ................................................................890

H.1.2.1. Dicamba-Tolerant Soy Biology .............................................................891

H.1.2.2. MON 87708 DMO and Gene Sequence Detection ..........................896

H.1.2.3. DT Soybean Safety Assessment............................................................900

H.1.2.4. Summary of Findings..............................................................................907

H.1.3. Dicamba-Tolerant Soy Presence in Food or Animal Feed ..........................................907

H.1.3.1. Probability of Presence...........................................................................908

H.1.3.2. Health Effects of MON 87708 DMO .................................................908

H.1.3.3. Summary of Findings..............................................................................909

H.2. Dicamba and Glufosinate-Tolerant Cotton .................................................................................909

H.2.1. Introduction ........................................................................................................................909

H.2.1.1. Cotton Biology and Usage .....................................................................909

H.2.1.2. Conventional Cotton Crop ....................................................................911

H.2.1.3. Gene and Gene Product.........................................................................911

H.2.1.4. Herbicides.................................................................................................911

H.2.2. Dicamba-and-Glufosinate-Tolerant Cotton Hazard Identification ............................912

H.2.2.1. DGT Cotton Biology..............................................................................912

H.2.2.2. DGT Cotton Safety Assessment...........................................................924
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 886 of 946

H.2.2.3. Summary of Findings..............................................................................933

H.2.3. Dicamba-and-Glufosinate-Tolerant Cotton Presence in Food or Animal 

Feed .................................................................................................................................933

H.2.3.1. Probability of Presence...........................................................................933

H.2.3.2. Health Effects of MON 88701 DMO, Dicamba Reaction 

Products, and PAT (bar).......................................................................................934

H.2.3.3. Summary of Findings..............................................................................935
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 887 of 946

Tables and Figures

Table H-1. 2012 Soybean Productivity by Region...................................................................................889

Table H-2. Tissues Collected and Analyzed for MON 87708 DMO...................................................892

Table H-3. Summary of the Levels of MON 87708 DMO1in Leaf, Root, Forage, and Seed 

from DT soybean Grown in 2008 U.S. Field Trials....................................................................894

Figure H-1: Australian Detection of Genetically Engineered Material in Various Foods 

(Griffiths et al., 2002).......................................................................................................................898

Table H-4. Summary of MON 88701 DMO Protein Levels in Tissues from DGT Cotton 

Grown in 2010 U.S. Field Trials....................................................................................................916

Table H-5. Summary of PAT (bar) Protein Levels in Tissues from DGT Cotton Grown in 

2010 U.S. Field Trials.......................................................................................................................918

Figure H-2: Australian Detection of Genetically Engineered Material in Various Foods 

(Griffiths et al., 2002).......................................................................................................................922
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H.1. Dicamba-Tolerant Soybean

H.1.1. Introduction

The scope of this section covers how DT soybean could be present in human food and animal feed 

and the potential health impacts of that presence. 

Soybean is the most widely grown oilseed in the world, with approximately 211 million metric tons 

of harvested seed produced in 2008. This represents 56% of world oilseed seed production that year 

(ASA 2012). Soybean is grown as a commercial crop in over 35 countries. The major producers are 

the U.S., Brazil, Argentina, China, India, and Paraguay, accounting for approximately 94% of the 

global soybean production in 2008. Approximately one-third of the 2008 world soybean production 

was in the U.S. (Soyatech, 2010). The U.S. was also the largest soybean seed exporting country in 

2008 (ASA, 2009). 

H.1.1.1. Soy Biology and Usage

Cultivated soybean, Glycine max (L.) Merr., is a diploidized tetraploid (2n=40), in the family 

Leguminosae, the subfamily Papilionoideae, the tribe Phaseoleae, the genus Glycine Willd. and the 

subgenus Soja (Moench) (OECD, 2000). It is an erect, bushy herbaceous annual that can reach a 

height of 1.5 metres.

Soybean is grown as a commercial crop in over 35 countries and is one of the most valued 

agricultural commodities because of its high protein and oil content. In 2008, soybean represented 

57% of world oilseed production, and approximately 33% of those soybean were produced in the 

U.S. In 2008, the U.S. exported 1.16 billion bushels (31.6 million metric tons) of soybean, which 

accounted for 40% of the world's soybean exports and was valued at $15.5 billion (ASA, 2009). 

Approximately 94% of the world’s soybean seed supply was crushed to produce soybean meal and 

oil in 2008 (Soyatech, 2010), and the majority was used to supply the feed industry for livestock use 

or the food industry for edible vegetable oil and soybean protein isolates.

The U.S. soybean acreage in the past 10 years has varied from approximately 64.7 to 77.5 million 

acres. Average soybean yields have varied from 33.9 to 44.0 bushels per acre over this same time 

period. According to data from USDA-NASS (2013a), soybean was planted on approximately 77.2 

million acres in the U.S. in 2012, producing 3.0 billion bushels of soybean with a value of $43.19 

billion (USDA-NASS, 2913a).

In the U.S., soybean production occurs in three major soybean growing regions accounting for 

99.1% of the soybean acreage: Midwest region (IL, IN, IA, KS, KY, MI, MN, MO, NE, ND, OH, 

SD, and WI), Southeast region (AL, AR, GA, LA, MS, NC, SC, and TN) and the Eastern Coastal 

region (DE, MD, NJ, NY, PA, and VA). Table H-1 shows the relative productivity of the three 

regions in 2008. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 889 of 946

Table H-1. 2012 Soybean Productivity by Region

Region

% 2012 U.S. 

Soybean Acreage

2008 Average Yield 

(bushels per acre)

Range of Average State 

Yields (bushels per acre)

Midwest/Plains 84.1 39.0 22.0 – 45.0

Southeast 13.1 42.1 34.0 – 46.0

Eastern Coastal 2.9 45.1 39.0 – 49.0

Source: USDA-NASS (2013a).

H.1.1.2. Conventional Soy Crop

Soybean has a long history of planting and production in North America. Soybean was originally 

introduced into North America from China in 1765 and has since been reintroduced several times 

by scientists, seed dealers, merchants, military expeditions, and various individuals (Singh and 

Hymowitz, 1999). Conventional plant breeding is based on the interplay and combination of genes 

present in the particular crop genome, and soybean is limited with regard to genetic diversity (Chung 

and Singh, 2008). 

Soybean is one of eight allergenic foods that are responsible for approximately 90% of all food 

allergies (Cordle, 2004). Soybean is less allergenic than other foods in this group and is rarely 

responsible for severe, life-threatening reactions (Cordle, 2004). Allergy to soybean is more 

prevalent in children than adults and is considered a transient allergy of infancy/childhood (Sicherer 

et al., 2000).

The conventional soybean variety A3525, used as the recipient for the dmo expression cassette 

insertion that produced DT soybean, was developed by Asgrow Seed Company. A3525 is a 

mid−maturity group III soybean variety with very high yield potential. A3525 has superior yields 

relative to varieties of similar maturity and has excellent agronomic characteristics (Steffen, 2004).

H.1.1.3. Gene and Gene Product

Production of a GE organism involves integration of a DNA cassette that is novel to a host plant 

into the host plant’s genomic DNA, called a transformation event. The DNA construct contains all 

the genetic information needed to produce the new characteristic or trait and, in most instances, this 

includes production of a protein. DT soybean contains a gene from Stenotrophomonas maltophilia that 

expresses a mono-oxygenase enzyme that rapidly demethylates dicamba and renders it inactive, 

thereby conferring tolerance to dicamba. The demethylation of dicamba produces 3,6-

dichlorosalicylic acid (DCSA), a known soybean, cotton, soil, and livestock metabolite whose safety 

has been evaluated by the Environmental Protection Agency (U.S. EPA, 2009), and formaldehyde, a 

compound that is naturally present in many plants and in the human body.

FDA enforces laws regarding the safety and labeling of food and feed. In 2011, Monsanto 

completed a voluntary consultation with FDA regarding the food and feed safety of DT soybean 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 890 of 946

(see appendix I). FDA considers a consultation to be completed when all food and feed safety 

issues and any regulatory issue are resolved (see appendix I; also see 

http://www.fda.gov/food/foodscienceresearch/biotechnology/submissions/default.htm). As part 

of this consultation, Monsanto discussed its findings that MON 87708 DMO is similar to the amino 

acid sequences of bacterial mono-oxygenases. MON 87708 DMO belongs to a common class of 

mono-oxygenases present in bacteria and plants currently widely prevalent in the environment and 

consumed by human and animals alike. Monsanto explained that: (1) there is an absence of known 

reports of allergies to S. maltophilia, which is the source of the dmo gene transferred to the recipient 

plant lines; (2) there is a lack of both structurally and immunologically relevant similarities between 

the amino acid sequences of MON 87708 DMO and known allergens, gliadins, and glutenins; (3) all 

forms of MON 87708 DMO are rapidly degraded in vitro in simulated gastric fluid and in simulated 

intestinal fluid.

H.1.1.4. Herbicides

Dicamba was approved by the U.S. EPA for agricultural uses in 1967 (U.S. EPA, 2009). Dicamba is 

formulated as a stand-alone herbicide product and marketed by several companies under various 

trade names such as Banvel®, Clarity®, Diablo®, Rifle®, and Sterling®that are various salt 

formulations of dicamba. These dicamba products can be tank mixed with one or more active 

ingredients depending on the treated crop. For example, Clarity can be tank mixed with over 75 

herbicide products in labeled crops. Additionally, dicamba is formulated as a registered premix 

product with one or more other herbicide active ingredients such as glyphosate, 2,4-D, 

diflufenzopyr, atrazine, nicosulfuron, metsulfuron, primsulfuron, triazulfuron, rimsulfuron and 

halosulfuron. Dicamba herbicide (e.g., Clarity – diglycolamine (DGA) salt of dicamba) is currently 

labeled for weed control in soybean, corn, cotton, sorghum, wheat, barley, oats, millet, pasture, 

rangeland, asparagus, sugarcane, turf, grass grown for seed, conservation reserve programs, and 

fallow croplands. 

Dicamba is currently labeled for use in conventional or Roundup Ready soybean, although dicamba 

use is extremely limited because applications are restricted to very early preplant and/or preharvest 

applications due to soybean tolerance concerns. The dicamba-treated acreage in 2011 soybean 

production was approximately 870,000 acres, representing 1.2% of the total soybean acreage. Upon 

integration of DT soybean into the Roundup Ready soybean system, dicamba herbicide use will be 

expanded to in-crop postemergence applications for those hard-to-control and herbicide-resistant 

broadleaf weeds found in U.S. soybean production. The impact that DT soybean will have on 

overall dicamba use will be dependent upon the level of DT soybean adoption by growers. Thus, 

the extent of dicamba-treated soybean acreage following the deregulation of DT soybean is difficult 

to forecast. Monsanto estimates dicamba-treated acres to ultimately be in the range of 30 to 50% of 

the total U.S. soybean acres. See Appendix A.

H.1.2. Dicamba-Tolerant Soy Hazard Identification

Soybean (Glycine max (L.) Merr.) is the most widely grown oilseed in the world. Soybean is grown 

primarily for the production of seed, has a multitude of uses in the food and industrial sectors, and 

represents one of the major sources of edible vegetable oil and of proteins for livestock feed use. 

Monsanto Company developed DT soybean to be tolerant to the herbicide dicamba. 
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H.1.2.1. Dicamba-Tolerant Soy Biology

DT soybean contains a dmo expression cassette that upon translation results in two forms of DMO 

protein; referred to as DMO and DMO+27. The active form of the proteins, necessary to confer 

dicamba tolerance, is a trimer comprised of three DMO monomers. In DT soybean, the trimer can 

be comprised of DMO, DMO+27, or a combination of both. Therefore, this document will refer to 

both forms of the protein and all forms of the trimer as MON 87708 DMO. 

DMO is an enzyme that catalyzes the demethylation of dicamba into the non-herbicidal compound 

DCSA and formaldehyde. DCSA is a known soybean, cotton, soil, and livestock metabolite whose 

safety has been evaluated by the EPA. Formaldehyde is found naturally in many plants at levels up 

to several hundred ppm. 

DT soybean was developed through Agrobacterium-mediated transformation of soybean meristem 

tissue using the binary transformation plasmid PV-GMHT4355. DT soybean contains one copy of 

the insert at a single integration locus. No additional genetic elements from the transformation 

vector were detected in the genome of DT soybean, including backbone sequence from plasmid PVGMHT4355. Additionally, the data confirm the organization and sequence of the insert, and 

demonstrate the stability of the insert over several generations. On the basis of these data, it is 

concluded that only the MON 87708 DMO is produced from the inserted DNA. Additionally, 

analyses of nutrient and anti-nutrient levels in both dicamba-treated and untreated DT soybean and 

a near-isogenic conventional control support the conclusion that soybean seed and forage produced 

from DT soybean are compositionally equivalent to that of conventional soybean. 

H.1.2.1.1. Characterization of DT soybean 

The safety assessment of crops derived through biotechnology includes characterization of 

the functional and physicochemical properties, and confirmation of the safety of the introduced 

protein. As stated previously, both forms of the protein and all forms of the trimer are referred to 

as the MON 87708 DMO. MON 87708 DMO was purified in sufficient quantities directly from the 

seed of DT soybean and used in subsequent safety assessment studies. Typically protein safety 

studies are conducted on proteins produced in heterologous expression systems, such as E. coli. 

Since the MON 87708 DMO used in the subsequent safety studies was purified directly from 

MON 87708 DMO, equivalence evaluations between plant-produced and bacterial-produced 

MON 87708 DMO was not necessary. The physicochemical characteristics and functional activity 

of the MON 87708 DMO were determined by a panel of analytical techniques, including: 1) 

western blot analysis to establish identity and immunoreactivity of MON 87708 DMO using an 

anti-DMO antibody, 2) N-terminal sequence analysis, 3) matrix-assisted laser desorption/ionization 

time-of-flight mass spectrometry (MALDI-TOF MS) to generate a tryptic peptide map of the 

MON 87708 DMO, 4) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to 

establish the apparent molecular weight of MON 87708 DMO, 5) glycosylation status of 

MON 87708 DMO, and 6) MON 87708 DMO activity analysis to demonstrate functional activity. 

The details of the materials, methods, and results are described in Appendix C of the Monsanto 

petition (Monsanto 2010), while the conclusions of the MON 87708 DMO characterization are 

summarized below. 

The identities of both forms of the DMO protein produced in DT soybean that constitute 

MON 87708 DMO were confirmed by western blot analysis by probing with an anti-DMO 
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antibody, N-terminal sequencing, and MALDI-TOF MS analysis of peptides produced after trypsin 

digestion. The antibody specifically detected DMO and DMO+27 on a western blot. The 

N-terminal sequence of the first 15 amino acid residues of both DMO and DMO+27 was identical 

to the predicted amino acid sequence, with the exception of the N-terminal methionine residue. 

MALDI-TOF MS analyses of DMO and DMO+27 yielded peptide masses consistent with their 

expected sequence. The apparent molecular weights of DMO and DMO+27 were 39.8 and 

42.0 kDa, respectively and neither were glycosylated. The MON 87708 DMO activity was 

determined by measuring the production of DCSA using dicamba as the substrate, resulting in a 

specific activity of 62.21 nmoles DCSA/min/mg of MON 87708 DMO. Taken together, these data 

provide a detailed characterization of the MON 87708 DMO isolated from the seed of DT soybean.

H.1.2.1.2. Expression Levels of MON 87708 DMO

The levels of MON 87708 DMO in various tissues of DT soybean that are relevant to the 

risk assessment were determined by a validated ELISA. Tissues of DT soybean and the near 

isogenic conventional soybean control A3525 were collected during the 2008 growing season from 

five field sites in the U.S.: Jefferson County, Iowa; Stark County, Illinois; Clinton County, Illinois; 

Parke County, Indiana; and Berks County, Pennsylvania. These field sites were representative of 

soybean producing regions suitable for commercial production. At each site, three replicated plots 

containing DT soybean, as well as the conventional control, were planted using a randomized 

complete block field design. Over-season leaf (OSL 1-4), root, forage, and seed tissues were 

collected from each replicated plot at all field sites (except for the conventional control from Berks 

County, Pennsylvania where only two replicates were collected). A description of tissues collected is 

provided in Table H-2.

Table H-2. Tissues Collected and Analyzed for MON 87708 DMO

Tissue Soybean Development Stage1 Days After Planting 

OSL-1 V3-V4 21-30

OSL-2 V5-V8 31-42

OSL-3 R2-V12 43-58

OSL-4 R5-V16 55-78

Root R6 70-91

Forage R6 70-91

Seed R8 109-147

1

Soybean plant growth stages described in Soybean Growth and Development (ISU, 2004).

The levels of MON 87708 DMO were determined in all seven tissue types as described in 

Table H-3. The ELISA assay detected all forms of MON 87708 DMO and therefore the levels 

represent the total of MON 87708 DMO. The results obtained from the ELISA analysis are 

summarized in Table H-3 and the details of the materials and methods are described in Appendix D 

to the Monsanto petition (Monsanto 2010). In summary, expression analysis of the samples from 

the 2008 U.S. field trial showed that MON 87708 DMO was detected in all tissue types across all 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 893 of 946

five sites ranging from 3.9 – 180 μg/g dry weight (dwt). The mean levels of the MON 87708 DMO 

across the five sites were highest in leaf (ranging from OSL-1 at 17 μg/g dwt, to OSL-4 at 69 μg/g 

dwt), followed by forage (53 μg/g dwt), seed (47 μg/g dwt), and root (6.1 μg/g dwt). As expected 

for the conventional control, the ELISA values for MON 87708 DMO were less than the limit of 

quantitation (LOQ) of the assay in all tissue types. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 894 of 946

Table H-3. Summary of the Levels of MON 87708 DMO1in Leaf, Root, Forage, and Seed

from DT soybean Grown in 2008 U.S. Field Trials

Tissue 

Type

Mean (SD)2

(μg/g fwt) 3

Range4

(μg/g fwt)

Mean (SD) 

(μg/g dwt)5

Range

(μg/g dwt)

LOQ/LOD

(μg/g fwt)6,7

OSL-1 3.1 (1.9) 0.87 – 6.8 17 (7.7) 6.2 – 29 0.63/0.20

OSL-2 5.2 (2.6) 1.4 – 9.8 31 (13) 12 – 54 0.63/0.20

OSL-3 6.0 (2.2) 3.5 – 11 44 (14) 25 – 71 0.63/0.20

OSL-4 16 (12) 4.6 – 43 69 (46) 23 – 180 0.63/0.20

Root 1.9 (0.73) 1.2 – 3.6 6.1 (2.1) 3.9 – 11 0.031/0.015

Forage 12 (2.5) 7.0 – 17 53 (18) 25 – 84 0.63/0.10

Seed 43 (7.7) 31 – 55 47 (8.7) 34 – 59 1.3/0.21

1 Represents total for MON 87708 DMO 

2 The mean and standard deviation (SD) were calculated (n=15). The “n” values for the calculated mean 

and standard deviations represent the number of samples figured into the calculation.

3 Protein levels are expressed as microgram (μg) of protein per gram (g) of tissue on a fresh weight (fwt) 

basis.

4 Minimum and maximum values were determined for each tissue type.

5 Protein levels are expressed as μg/g dwt. The dry weight values were calculated by dividing the μg/g fwt 

by the dry weight conversion factors obtained from moisture analysis data.

6 The limit of quantitation (LOQ) was calculated based on the lowest DMO standard concentration. The 

“ng/ml” value was converted to “μg/g fwt” using the respective dilution factor and tissue-to-buffer ratio. 

7 The limit of detection (LOD) was calculated as the mean value plus three SD using the data generated 

with conventional control sample extracts for each tissue type. The LOD value in “ng/ml” was

converted to “μg/g fwt” using the respective dilution factor and tissue-to-buffer ratio. 

H.1.2.1.3. Compositional Assessment

Monsanto conducted analyses of nutrient and anti-nutrient levels in both dicamba-treated and 

untreated DT soybean and the near isogenic conventional control A3525 to assess compositional 

equivalence. The tissues analyzed included seed and forage harvested from plants grown at five field 

sites in the U.S. during the 2008 field season. The composition analysis, conducted in accordance 

with OECD guidelines, also included measurement of nutrients and anti-nutrients in the commercial 

reference varieties concurrently grown with DT soybean to provide data on natural variability of 

each compositional component. All soybean plants including DT soybean, the conventional 

control, and the commercial reference varieties were treated with maintenance pesticides as 

necessary throughout the growing season. In addition, DT soybean plots were either treated at the 

V2-V3 growth stage with dicamba herbicide at the maximum in-crop label rate (0.5 lb a.e./acre) or 

not treated with dicamba herbicide. 

For DT soybean treated, the combined-site analysis of both seed and forage showed no statistically 

significant differences between DT soybean and conventional control for 21 (42.0%) of the 50 mean 

value comparisons. Of the statistically significant differences observed, one was from the forage 

analysis, and 28 were from the seed analysis. Nutrient component differences in seed included mean 
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values for ash, carbohydrates by calculation, protein and 12 amino acids, five fatty acids, ADF, 

NDF, crude fiber, and vitamin E. In the combined-site analysis, all nutrient component differences 

in seed between DT soybean and the conventional control were of small relative magnitude with 

respect to the conventional control and, whether increased or decreased, ranged from 1.51% to 

12.37% for the three proximates, amino acids, fatty acids, and fibers, and 15.13% for vitamin E. 

Two of the nutrient components in the combined-site analysis (decreased levels of 18:1 oleic acid 

and increased levels of 18:3 linolenic acid) were also observed to be statistically different at all five 

individual sites, and one nutrient component (vitamin E) was observed to be increased at four of the 

five individual sites as in the combined-site analysis. The other combined-site differences occurred 

at fewer or none of the individual sites. Anti-nutrient component differences in seed were observed 

in mean values for phytic acid, raffinose, stachyose, and daidzein. In the combined-site analysis, all 

anti-nutrient component differences in seed between DT soybean and the conventional control were 

of small relative magnitude with respect to the conventional control, and ranged from a 6.14% 

decrease (phytic acid) to an 11.51% increase (daidzein). None of the anti-nutrient components were 

observed to be statistically different at more than two of the five individual sites. The only nutrient 

component difference in forage for the combined-site analysis was observed in ADF and its relative 

magnitude of difference, with respect to the conventional control, was 10.45%. No differences 

between DT soybean and the conventional control ADF mean values were observed at any of the 

five individual sites. Mean values of DT soybean components with statistically significant 

differences to the conventional control were all within the 99% tolerance interval established from 

the commercial reference varieties grown concurrently and at the same field sites, as well as ranges in 

the scientific literature and the ILSI Crop Composition Database.

For DT soybean (untreated) the combined-site analysis of both seed and forage showed no 

statistically significant differences between DT soybean (untreated) and conventional control for 30 

(60.0%) of the 50 mean value comparisons. Of the statistically significant differences observed, 

none were from the forage analysis, and 20 were from the seed analysis. Nutrient component 

differences in seed included mean values for protein and eight amino acids, five fatty acids, ADF, 

NDF, and vitamin E. In the combined-site analysis, all nutrient component differences in seed 

between DT soybean (untreated) and the conventional control were of small relative magnitude with 

respect to the conventional control and, whether increased or decreased, ranged from 1.45% to 

7.60% for protein and amino acids, fatty acids, and fibers, and 18.16% for vitamin E. None of the 

nutrient components in the combined-site analysis were observed to be statistically different at all 

five individual sites. Anti-nutrient component differences in seed were observed in mean values for 

trypsin inhibitor, daidzein, and genistein. In the combined-site analysis, all anti-nutrient component 

differences in seed between DT soybean (untreated) and the conventional control were of small 

relative magnitude, with respect to the conventional control, and ranged from an 11.59% increase 

(genistein), 15.37% increase (trypsin inhibitor), and a 17.24% increase (daidzein). None of the antinutrient components from the combined-site analysis were observed to be statistically different at 

more than one of the five individual sites. No nutrient component differences in forage for the 

combined-site analysis were observed. Mean values of DT soybean components with statistically 

significant differences to the conventional control were all within the 99% tolerance interval 

established from the commercial reference varieties grown concurrently and at the same field sites, 

as well as ranges in the scientific literature and the ILSI Crop Composition Database. 

In summary, a comprehensive evaluation of key nutrients and anti-nutrients in seed and key 

nutrients in forage for both dicamba-treated and untreated DT soybean supports the conclusion that 

soybean seed and forage produced from DT soybean are compositionally equivalent to that of 
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conventional soybean and that neither the dicamba tolerance trait in DT soybean, nor the dicamba 

herbicide treatment, applied according to maximum in-crop label rates (including the associated 

dicamba residue levels) have a meaningful impact on the composition and therefore on the food and 

feed safety or the nutritional quality of DT soybean compared to conventional soybean.

H.1.2.2. MON 87708 DMO and Gene Sequence Detection

Monsanto has committed to best industry practices on seed quality assurance and control to ensure 

the purity and integrity of DT soybean seed. Before commercializing DT soybean in any country, 

Monsanto has pledged to make a DT soybean detection method available to soybean producers, 

processors, and buyers.

H.1.2.2.1. MON 87708 DMO and Gene Sequence Detection Methods

Methods for detecting GE materials range in their limits of detection. In many situations, a test will 

be required that not only detects the presence of GE material, but also measures the amount of GE 

content in the sample. All testing methodologies detect either the inserted DNA or the expressed 

protein resulting from the inserted DNA. The major detection methods for transgenic proteins are 

Enzyme Linked Immunosorbent Assays (ELISAs), and make use of the properties of antibodies. 

ELISAs are easy to use, robust and cheaper than DNA detection methods but generally less 

sensitive (Griffiths et al., 2002). In contrast to protein detection assays, assays designed to detect 

transgenic DNA are more sensitive. The most commonly used DNA amplification method is the 

Polymerase Chain Reaction (PCR), though there are other amplification methods to suit specific 

applications.

For each testing method, a Limit of Detection (LOD) is defined to show the sensitivity of the 

method. For example, a method with an LOD of 1 percent (w/w) for GT soy would be able to 

detect GT soy in a batch of soy flour when present as 1 percent (w/w) of the total soy flour 

(Griffiths et al., 2002). It is important to note that this LOD value written in an abbreviated form 

means the LOD for GT soy is 1 percent (w/w) of total soy flour if the product is comprised of 100 

percent soy (Griffiths et al., 2002). For food products containing several ingredients, estimation of 

the LOD is less reliable. Using the previous example, if the 1 percent (w/w) GE soy flour were used 

as a baking ingredient in cake, the soy flour may make up only 0.5 percent (w/w) of the total cake 

ingredients. The GE soy would thus be only 0.005 percent (w/w) of the total sample, which would 

be well below the LOD for this method (Griffiths et al., 2002). The LOD is normally defined on a 

percent (w/w) basis, the actual measurement of GE ingredients is based on either DNA or protein 

and this DNA- or protein-based measurement is not necessarily directly transferable to a percent 

(w/w) measurement (Griffiths et al., 2002). Some highly processed foods contain no traces of DNA 

and/or protein. In these cases, there is no analytical method available to identify whether these 

products are derived from GE materials.

H.1.2.2.2. Labeling Standards

In the United States, foods derived from GE plants are not required to indicate on the food label 

that they were derived from plants produced through the use of biotechnology with the exception of 

resultant foods that have a change in composition. While Australia has a labeling threshold level of 1 

percent for unintended GE material, other countries such as Japan and Korea currently have a 

higher labeling threshold level of 5 percent (Griffiths et al., 2002). At present, European Union 
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Regulations 2003/1829/EC and 2003/1830/EC govern the use of GE ingredients intended for 

food, feed, and food additives. The threshold for labeling of food and feed is 0.9% for presence of 

approved GE material. Unapproved events are managed with zero tolerance (Alexander et al., 

2007), however the EU has implemented a technical threshold for feed that is set at 0.1%. Products 

such as milk, meat, and eggs, and that are derived from livestock fed transgenic feeds are exempt 

from labeling laws in the EU and other countries with mandatory GE food labeling provisions. 

Other foods produced with GM technology, such as cheese produced with GM enzymes, wine and 

beer produced with GE yeasts, are exempted from EU-labeling as well. Currently, only the EU and 

Switzerland have labeling regulations specifically pertaining to GE feed (Griffiths et al., 2002; 

Alexander et al., 2007; ISAAA, 2005).

H.1.2.2.3. Detection in Food Products

There is some literature available on the detection and quantification of GE material in various 

foods. In an Australian monitoring study (Griffiths et al., 2002), the GT trait was detected in soy 

flour, soy protein isolate, soy milk, snack foods, biscuits, powdered bread, and corn flour as 

illustrated in Figure H-1 below.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 898 of 946

Figure H-1: Australian Detection of Genetically Engineered Material in Various Foods (Griffiths et al., 2002)
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 899 of 946

H.1.2.2.4. Detection of MON 87708 DMO and Gene Sequence in Downstream Animals

The European Food Safety Authority (EFSA) has reported that a large number of experimental 

studies have shown that recombinant DNA consumed by livestock has not been subsequently 

detected in tissues, fluids, or edible products of these farm animals (EFSA 2007). DNA has always 

been present in food and, upon consumption, is quickly degraded by restriction nucleases present in 

the gastrointestinal tract of humans and animals to nucleic acids. According to the U.S. FDA 

(1992), nucleic acids are present in the cells of every living organism, do not raise concerns as a 

component of food, and are generally recognized as safe. Results from an International Life 

Sciences Institute (ILSI) workshop on safety considerations of DNA in food were reported (Jonas et 

al., 2001) and confirmed that: 1) all DNA, including recombinant DNA, is composed of the same 

four nucleotides; 2) there are no changes to the chemical characteristics or the susceptibility to 

degradation by chemical or enzymatic hydrolysis of recombinant DNA as compared to 

non-recombinant DNA; and 3) there is no evidence that DNA from dietary sources has ever been 

incorporated into the mammalian genome. 

As described by the European Food Safety Authority (EFSA) in 2007 the fate of recombinant DNA 

from genetically engineered plants or resultant proteins are dependent on the following four factors:

 the fate of the recombinant DNA and protein during the feed processing and ensilaging;

 the fate of the recombinant DNA and protein in the gastrointestinal tract of animals fed 

with the GE feed;

 the potential absorption of the digested pieces of DNA or protein into animal 

tissues/products; and 

 the potential of biological functionality of absorbed DNA and protein fragments. 

No study has found that mechanical treatment (e.g., baling, chopping, processing) of animal feed has 

effect on DNA stability (EFSA). Digestion in the gut generally causes DNA and protein to be 

broken down to the original nucleotides and amino acids respectively. The inserted DNA and 

protein expressed from the inserted DNA are not expected to be digested in any different manner 

simply because they are present in the food due to the use of biotechnology.

For example, in field tests, CP4 EPSPS, the inserted gene sequence in glyphosate-tolerant (GT) 

soybeans, was found in GT soybean at 0.1 percent in chicken feed (Ash et al., 2003) by an ELISA 

method; no detectable amounts of CP4 EPSPS protein were in whole egg, egg albumen, liver, or 

feces of the chickens fed GT soybeans.

Conventional PCR/Southern Blot and an ELISA method were utilized to determine if transgenic 

DNA or protein were detectable in pigs fed GT soybeans (Jennings et al., 2003). The authors report 

that there was an absence of detectable levels of fragments of either transgenic DNA or protein. By 

contrast Sharma (2006) reported detection of transgenic DNA in intestinal tissue.

Quantitative real-time PCR and conventional PCR were used to evaluate GT canola cp4 epsps

transgene in the intestines, rumen, or feces of sheep feed canola meal (Alexander et al., 2004). 

Digestion of plant material and release of tDNA (including transgenic DNA) can occur in the small 

intestine of sheep. The free transgenic DNA is rapidly degraded at neutral pH in small intestine 

duodenal fluid, thus reducing the likelihood that intact transgenic DNA would be available for 
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absorption through the Peyer’s Patches further down in the distal ileum of the small intestine 

(Alexander et al., 2004).

The persistence of plant-derived recombinant DNA in sheep and pigs fed GE (GT) canola was 

assessed by Sharma et al. (2006) utilizing PCR and Southern hybridization analysis of DNA 

extracted from digesta, GI tract tissues, and visceral organs. This study confirmed that DNA 

fragments ingested in feed do survive to the terminal GI tract and that uptake into gut epithelial 

tissues does occur. A very low frequency of transmittance to visceral tissue was confirmed in pigs, 

but not in sheep. There was no evidence to suggest that recombinant DNA would be processed in 

the gut in any manner different from endogenous feed-ingested genetic material.

A study by Netherwood et al. (2004) and the discussion by Heritage (2004) address the finding by 

Netherwood et al. of evidence of low-frequency EPSPS gene transfer from genetically engineered 

soya to the microflora of the small bowel. However, the microflora contained only fragments 

EPSPS; the full length gene was not detected, and it could not be determined whether it was the 

bacteria themselves that contained the fragments.

H.1.2.3. DT Soybean Safety Assessment

H.1.2.3.1. MON 87708 DMO Safety Assessment

FDA enforces laws regarding the safety and labeling of food and feed. In 2011 Monsanto 

completed a voluntary consultation with FDA regarding the food and feed safety of DT soybean. 

See Appendix I. FDA considers a consultation to be completed when all safety and regulatory issues 

are resolved. See Appendix I. As part of the consultation, Monsanto discussed its finding that the 

MON 87708 DMO belongs to a common class of mono-oxygenases present in bacteria and plants 

currently widely prevalent in the environment and consumed.

Regarding the food and feed safety of MON 87708 DMO, the available data demonstrate that 

harvested seed is as safe as conventional soybean for food and feed uses; thus it is safe and 

wholesome for consumption. To assess the impact of MON 87708 DMO on food and feed safety, 

bioinformatic analyses were used to establish the lack of both structurally and immunologicallyrelevant similarities between DT soybean and allergens or toxins, based on the amino acid sequence 

of MON 87708 DMO. Furthermore, digestive fate experiments conducted with MON 87708 DMO 

demonstrate rapid digestion in simulated gastric fluid (SGF), a characteristic shared among many 

proteins with a history of safe consumption. Rapid digestion of MON 87708 DMO in SGF 

indicates that it is highly unlikely that MON 87708 DMO will reach absorptive cells of the intestinal 

mucosa. This, combined with the history of safe consumption of mono-oxygenases (the class of 

enzymes to which MON 87708 DMO belongs) and the lack of homology of the amino acid 

sequence to known allergens and toxins, supports a conclusion that MON 87708 DMO has low 

allergenic and toxic potential. Finally, a high dose of MON 87708 DMO in a mouse acute oral 

toxicity evaluation demonstrated that it is not acutely toxic, and does not cause any adverse effect. 

The safety assessment supports the conclusion that exposure to MON 87708 DMO poses no 

meaningful risk to human or animal health. 
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H.1.2.3.1.1. Donor Organism Safety

The safety of the donor organism was discussed in Monsanto’s consultation with the FDA. In this 

consultation, Monsanto explained that the dmo gene is derived from the bacterium Stenotrophomonas 

maltophilia (Palleroni and Bradbury, 1993). 

S. maltophilia is ubiquitous in the environment and is found associated with the rhizosphere of plants. 

S. maltophilia can be found in a variety of foods and feeds, and is widespread in the home 

environment (Berg et al., 1999; Denton and Kerr, 1998; Echemendia, 2010). Exposure to 

S. maltophilia is incidental to its presence in food. It has been isolated from “ready to eat” salads, 

vegetables, frozen fish, milk, and poultry (Qureshi et al., 2005; Ryan et al., 2009). S. maltophilia can 

be found in healthy individuals without causing any harm to human health (Denton et al., 1998) and 

infections caused by S. maltophilia are extremely uncommon (Cunha, 2010). Strains have been found 

in the transient flora of hospitalized patients as a commensal organism (Echemendia, 2010) and, 

similar to the indigenous bacteria of the gastrointestinal tract, S. maltophilia can be an opportunistic 

pathogen (Berg, 1996). As such, S. maltophilia is of low virulence in immuno-compromised patients 

where a series of risk factors (severe debilitation, the presence of indwelling devices such as 

ventilator tubes or catheters, for prolonged periods of time and prolonged courses of antibiotics) 

must occur for colonization by S. maltophilia in humans (Ryan et al., 2009). Therefore, infections by 

S. maltophilia almost exclusively occur in hospital settings, in which case they are only present in a 

minimal percentage of infections (Ryan et al., 2009). Finally, S. maltophilia has not been reported to 

be source of allergens. 

The ubiquitous presence of S. maltophilia in the environment, the presence in healthy individuals 

without causing infections, the incidental presence in foods without any adverse safety reports, and 

the lack of reported allergenicity establishes the safety of the donor organism.

H.1.2.3.1.2. MON 87708 DMO Belongs to a Common Class of Mono-Oxygenases

In its consultation with FDA, Monsanto also discussed the similarity of MON 87708 DMO to a 

common class of mono-oxygenases regularly consumed by humans and animals. MON 87708 

DMO is classified as an oxygenase. Oxygenases are enzymes that incorporate one or two oxygen 

atoms into substrates and are widely distributed in many universal metabolic pathways (Harayama et 

al., 1992). Within this large enzymatic class are mono-oxygenases that incorporate a single oxygen 

atom as a hydroxyl group with the concomitant production of water and oxidation of NAD(P)H 

(Harayama et al., 1992). Non-heme iron oxygenases, where iron is involved in the catalytic site, are 

an important class of oxygenases. Within this class are Rieske oxygenases, which contain a Rieske 

iron-sulfur [2Fe-2S] cluster. All Rieske non-heme iron oxygenases contain two catalytic domains, a 

non-heme iron domain (nh-Fe) that is a site of oxygen activation, and a Rieske [2Fe-2S] domain 

(Ferraro et al., 2005). MON 87708 DMO belongs to this class of oxygenases which are found in 

diverse phyla ranging from bacteria to plants (Ferraro et al., 2005; Schmidt and Shaw, 2001). 

The crystal structure of a DMO has been solved (D'Ordine et al., 2009; Dumitru et al., 2009). The 

crystallography results demonstrated that, similar to all Rieske non-heme iron oxygenases, DMO 

contains two catalytically important and highly conserved domains; a mononuclear non-heme iron 

domain (nh-Fe) that is a site of oxygen activation, and a Rieske [2Fe-2S] domain (D'Ordine et al., 

2009; Dumitru et al., 2009; Ferraro et al., 2005). The amino acids binding the non-heme iron and 

those that constitute the Rieske [2Fe-2S] domain in the DMO protein are also highly conserved in 
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these plant proteins, as is their spatial orientation (D'Ordine et al., 2009; Ferraro et al., 2005). Rieske 

domains are ubiquitous in numerous bacterial and plant proteins, like the iron-sulfur protein of the 

cytochrome bc1 complex, chloroplast cytochrome b6/f complex, and choline mono-oxygenases 

(Breyton, 2000; Darrouzet et al., 2004; Gray et al., 2004; Hibino et al., 2002; Rathinasabapathi et al., 

1997; Russell et al., 1998). The presence of two conserved domains, a Rieske [2Fe-2S] domain and a 

mononuclear iron domain, suggests that all Rieske type non-heme iron oxygenases share the same 

reaction mechanism, by which the Rieske domain transfers electrons from the ferredoxin to the 

mononuclear iron to allow catalysis (Chakraborty et al., 2005; Dumitru et al., 2009; Ferraro et al., 

2005). The structure and mechanistic homologies are further evidence of the evolutionary 

relatedness of all Rieske non-heme iron oxygenases to each other (Nam et al., 2001; Rosche et al., 

1997; Werlen et al., 1996). Additionally, a FASTA alignment search of publicly available databases 

using the DMO+27 sequence as a query yielded homologous sequences from many different 

species, predominantly bacteria, with amino acid sequence identity ranging up to approximately 

42%. Homologous oxygenases are also present in plants, including such crops as rice (Orysa sativa), 

canola (Brassica napus), and corn (Zea mays), with sequence identity up to 24%. The highest 

homology was observed to pheophorbide A oxygenases from corn, canola and pea (Pisum sativum). 

Pheophorbide A oxygenase is also a Rieske-type oxygenase that plays a key role in the overall 

regulation of chlorophyll degradation in plants (Rodoni et al., 1997). The protein is constitutively 

present in all green tissues and, at slightly lower levels, in etiolated and non-photosynthetic tissues 

including seeds (Yang et al., 2004). 

Therefore, MON 87708 DMO shares sequence identity and many catalytic and domain structural 

similarities with a wide variety of oxygenases present in bacteria and plants currently widely 

prevalent in the environment and consumed, establishing that animals and humans are extensively 

exposed to these types of enzymes.

H.1.2.3.1.3. DMO is a Dicamba-Specific Mono-Oxygenase

DMO converts dicamba to DCSA. In Monsanto’s consultation with FDA, Monsanto described its 

research demonstrating that this demethylation is very specific to dicamba, where both the 

carboxylate moiety and the chlorine atoms help position the substrate at the active site of the 

enzyme (D'Ordine et al., 2009; Dumitru et al., 2009). Crystallography studies of the substrate in the 

active site demonstrated that these chlorines function as steric “handles” that position the substrate 

in the proper orientation in the binding pocket (Dumitru et al., 2009). Potential substrates abundant 

in soybean (o-anisic acid, vanillic acid, syringic acid, ferulic acid and sinapic acid) that are structurally 

similar to dicamba, were not metabolized by an E. coli-produced DMO in laboratory tests indicating 

that the DMO enzyme is specific for dicamba (Monsanto 2010). The E. coli-produced DMO is 

similar in sequence and function to MON 87708 DMO; therefore, it is appropriate to extend 

specificity data generated with the E. coli-produced DMO to MON 87708 DMO. Given the limited 

amount of chlorinated metabolites with structures similar to dicamba in plants and other eukaryotes

(Wishart, 2010; Wishart et al., 2009), it is unlikely that MON 87708 DMO will catalyze the 

conversion of other endogenous substrates. Therefore, the activity of the enzyme is specific for 

dicamba, while maintaining many structural properties common to oxygenases that are ubiquitous to 

all organisms.
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H.1.2.3.1.4. DT soybean Allergenicity

The potential allergenicity of DT soybean was evaluated in Monsanto’s consultation with the FDA. 

The allergenic potential of an introduced protein is assessed by comparing the biochemical 

characteristics of the introduced protein to biochemical characteristics of known allergens (Codex 

Alimentarius, 2003). A protein is not likely to be associated with allergenicity if: 1) the protein is 

from a non-allergenic source, 2) the protein represents a very small portion of the total plant protein, 

3) the protein does not share structural similarities to known allergens based on the amino acid 

sequence, and 4) the protein is rapidly digested in mammalian gastrointestinal systems. MON 87708 

DMO, as defined above, refers to all forms of the protein and the resulting trimer, and has been 

assessed for its potential allergenicity according to these safety assessment guidelines.

1) MON 87708 DMO originates from S. maltophilia, an organism that has not been reported 

to be a source of known allergens. 

2) MON 87708 DMO represents no more than 0.01% of the total protein in the seed of 

DT soybean. 

3) Bioinformatics analyses demonstrated that the DMO+27 form of MON 87708 DMO, 

that also contains the DMO sequence, does not share amino acid sequence similarities 

with known allergens and, therefore, is highly unlikely for DMO or DMO+27 to contain 

immunologically cross-reactive allergenic epitopes. 

4) In vitro digestive fate experiments conducted with the MON 87708 DMO demonstrate 

that the proteins are rapidly digested in simulated gastric fluid (SGF) and in simulated 

intestinal fluid (SIF). 

Taken together, these data support the conclusion that MON 87708 DMO does not pose a 

significant allergenic risk to humans or animals.

H.1.2.3.1.5. MON 87708 DMO is Labile in in vitro Digestion Assays

MON 87708 DMO was readily digestible in SGF and SIF. Rapid degradation of the MON 87708 

DMO in SGF and SIF makes it highly unlikely that the MON 87708 DMO would be absorbed in 

the small intestine and have any adverse effects on human or animal health. 

H.1.2.3.1.6. MON 87708 DMO Toxicity

Monsanto’s consultation with the FDA also included an evaluation of the potential toxicity of MON 

87708 DMO. Monsanto explained that an acute oral toxicology study was conducted with 

MON 87708 DMO. Results indicate that MON 87708 DMO did not cause any adverse effects in 

mice, with a No Observable Adverse Effect Level (NOAEL) of 140 mg/kg body weight (BW), the 

highest dose level tested.

Potential human health risks from consumption of foods derived from DT soybean were evaluated 

using a Margin of Exposure (MOE) approach. The MOE is a ratio of two factors which assesses 

for a given population the dose at which a small but measurable adverse effect is first observed and 

the level of exposure to the substance considered. A MOE was calculated between the acute mouse 

NOAEL (140 mg/kg BW) for the MON 87708 DMO and 95th percentile “eater-only” estimates of 

acute dietary exposure determined using the Dietary Exposure Evaluation Model (DEEM-FCID 

version 2.03, Exponent Inc.). DEEM food consumption data are obtained from the 1994-1996 and 
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1998 USDA Continuing Survey of Food Intakes by Individuals (CSFII). The MOEs for acute 

dietary intake of MON 87708 DMO were estimated to be 24,800 and 600 for the general population 

and non-nursing infants, the sub-population with the highest estimated exposure, respectively. 

These very large MOEs, in addition to the above mentioned protein safety data for MON 87708 

DMO, support the conclusion that there is no meaningful risk to human health from dietary 

exposure to MON 87708 DMO. 

Potential health risks to animals from the presence of MON 87708 DMO in feed were evaluated by 

calculating an estimate of daily dietary intake (DDI). In the worst case scenario, the percentage of 

MON 87708 DMO consumed from DT soybean as a percentage of the daily protein intake for a 

dairy cow is 0.0396% and for both the broiler and pig is less than 0.0121%. These very small levels 

of exposure of animals to MON 87708 DMO in their feed, in addition to the above mentioned 

safety data for MON 87708 DMO, support the conclusion that there is no meaningful risk to animal 

health when DT soybean is present in their diets. 

H.1.2.3.1.7. DT soybean Safety Assessment Conclusions

MON 87708 DMO is an oxygenase that catalyzes the O-demethylation of the herbicide dicamba. 

MON 87708 DMO was derived from S. maltophilia, which is an environmentally ubiquitous 

bacterium that does not pose a health risk to healthy individuals. MON 87708 DMO is a 

Rieske-type mono-oxygenase that has homologs in bacteria and plants that share many of the typical 

structural and functional characteristics of these types of oxygenases, while maintaining specificity 

for its substrate. MON 87708 DMO was fully characterized confirming both the N-terminal and 

internal amino acid sequence and the lack of glycosylation. MON 87708 DMO was isolated from 

DT soybean and was used for the described safety studies; therefore an equivalence evaluation to the 

protein produced in a heterologous expression system was not required. Expression studies using 

ELISA demonstrated that MON 87708 DMO was expressed in all tissues assayed at levels ranging 

from 3.9 – 180 μg/g dwt, representing a low percentage of the total protein in soybean. 

Bioinformatics analysis determined that MON 87708 DMO does not share amino acid sequence 

similarities with known allergens, gliadins, glutenins, or protein toxins. MON 87708 DMO was 

rapidly digested in in vitro assays using simulated gastric and intestinal fluids and did not show any 

adverse effects when administered to mice via oral gavage at levels that resulted in large MOEs. 

Together with the safety data, these data support a conclusion that there is no meaningful risk to 

human health from dietary exposure to MON 87708 DMO. 

Using the guidance provided by the FDA in its 1992 Policy Statement regarding the evaluation of 

New Plant Varieties, a conclusion of “no concern” is reached for the donor organism and 

MON 87708 DMO. The food and feed products containing DT soybean or derived from DT 

soybean are as safe as soybean currently on the market for human and animal consumption.

H.1.2.3.2. Dicamba Reaction Product Safety Assessment

MON 87708 DMO rapidly demethylates dicamba rendering it inactive, thereby conferring tolerance 

to dicamba in DT soybean. In dicamba-treated DT soybean, the demethylation of dicamba 

produces 3,6-dichlorosalicylic acid (DCSA), a known soybean, cotton, soil, and livestock metabolite 

whose safety has been evaluated by the Environmental Protection Agency (U.S. EPA), and 

formaldehyde. In the absence of a dicamba treatment on DT soybean, DCSA and formaldehyde 

would not be produced. DCSA is structurally similar to salicylic acid (SA). Numerous studies have 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 905 of 946

reported on the stress defense activities of SA, although most studies have looked at the protective 

effects of exogenously applied SA (Janda et al, 2007). Formaldehyde has a potential linkage to 

apoptosis in plants (Szende and Tyihak, 2010), and formaldehyde concentrations in plants have been 

found to increase under certain stress conditions (Szabo et al, 2003). The National Toxicology 

Program (NTP) 12th Report on Carcinogens has reclassified formaldehyde as a known human 

carcinogen (USHHS-NTP, 2011). The relevant route of exposure for this health risk is from 

repeated inhalation at levels associated with indoor or occupational environments, which are 

generally higher than outdoor environments (USHHS-NTP, 2011). Formaldehyde is present in food 

and in the human body naturally, and there is no evidence to suggest that dietary intake of 

formaldehyde is important (USHHS-NTP, 2011). 

A full discussion on DCSA, and the safety of this metabolite, is provided in Appendices M and L of 

the Monsanto petition (Monsanto 2010). DCSA as well as other dicamba metabolite products were 

measured in the residue study provided to the EPA to demonstrate that dicamba and dicamba 

metabolite residues are well below the current MRL set for dicamba in soybeans in the U.S.

Formaldehyde is ubiquitous in the environment and present in plants and animals. Formaldehyde 

was not considered a relevant metabolite in the demethylation of dicamba by the EPA. According 

to the guidelines published by Office of Prevention, Pesticides and Toxic Substances, United States 

Environmental Protection Agency (US EPA OPPTS 860.1300), the methoxy sidechain that is 

cleaved from dicamba to form formaldehyde would specifically not be chosen to be labeled in a 

metabolism study (U.S. EPA, 1996). This is because it is not metabolically stable and would not be 

considered a significant moiety, as it would be readily metabolized and incorporated into the 1-

carbon pool of the plant through known pathways. Therefore, formaldehyde was not measured in 

the residue study when dicamba was applied to DT soybean.

Data from both dicamba-treated and non-treated DT soybean compared to a conventional control 

are available from multiple sites across the U.S. where agronomic, phenotypic and observational 

environmental interaction data were collected. The results of this assessment demonstrate no 

biologically meaningful difference between DT soybean treated with dicamba, or DT soybean not 

treated with dicamba compared to the conventional control, and support a conclusion that the 

formation of DCSA and formaldehyde does not alter the weedy characteristics, or increased 

susceptibility and tolerance to diseases, insects or abiotic stresses. Therefore, DT soybean, as 

cultivated, is no more likely to be a plant pest risk or have a biologically meaningful change in

environmental impact than conventional soybean.

Further, the metabolism of formaldehyde in plants is well understood, and there are a number of 

natural occurring sources of formaldehyde in plants. For example, it is produced during the process 

of photorespiration (Oliver, 1994) and during oxidative demethylation of DNA (Zhu, 2009), which 

supports why formaldehyde is not considered a byproduct of interest as dicamba is demethylated. It 

is well known and understood that formaldehyde is rapidly metabolized in plants through two basic 

routes: 1) it can be incorporated into the one-carbon folate pool via spontaneous or enzymemediated formation of methylene tetrahydrofolate (Hanson and Roje, 2001); or 2) it can be oxidized 

to formate by a detoxification pathway that begins with spontaneous formation of the glutathione 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 906 of 946

adduct S-hydroxymethylglutathione (Hanson and Roje, 2001). In each case, formaldehyde is further 

metabolized to carbon dioxide or entered into the 1C folate pool (Hanson and Roje, 2001; Giese et

al., 1994). The maximum theoretical production of formaldehyde produced from dicamba-treated 

DT soybean is estimated to be 16.7 and 37.5 mg/kg247. This is well within the range of 

formaldehyde concentrations measured for a variety of agricultural commodities – up to 60 mg/kg 

in fruits and vegetables (WHO-IPCS, 1989). Plants have a large capacity to metabolize 

formaldehyde naturally produced from internal processes (A. Hanson (2011), C.V. Griffin, Sr. 

Eminent Scholar, Horticulture Department, University of Florida, Personal Communication), and 

any additional amount of formaldehyde that could be theoretically produced in the plant by dicamba 

treatment in DT soybean would be metabolized very quickly. Additionally, as dicamba would not be 

instantaneously absorbed and metabolized, the incremental increase in formaldehyde over and above 

the levels already presumed to be present in the soybean plant would be small and transient. 

Further, since current literature supports that formaldehyde is only emitted from foliage under 

certain conditions (Nemecek-Marshall et al., 1995; Cojocariu et al., 2004; Cojocariu et al., 2005) and 

that emission rates are low (Nemecek-Marshall et al., 1995), little opportunity exists for 

formaldehyde to be released from DT soybean after dicamba treatment. 

In addition to formaldehyde production in plants, plants and animals are constantly exposed to low 

levels of formaldehyde. Formaldehyde is already present in the environment and the atmosphere 

from a variety of biogenic (e.g. plant and animal) and anthropogenic (e.g. automotive or industrial 

emissions) sources. Additionally, formaldehyde degrades rapidly in environmental compartments 

(air, soil, and water). In water, formaldehyde dissipates through biodegradation to low levels in a 

few days (USHHS-ATSDR, 1999). Aerobic biodegradation half-lives are estimated to be 1-7 days 

for surface water and 2-14 days for ground water (US EPA, 2008). The half-life of formaldehyde in 

air is dependent on a number of factors (light intensity, temperature and location). Through 

reaction with hydroxyl radical, the half-life of formaldehyde in air varies from 7 to 70 hours (US 

EPA, 2008). The photolytic half-life of formaldehyde in air (e.g., in the presence of sunlight) is 

estimated to be 1.6-6 hours (US EPA, 2008; USHHS-ATSDR, 1999). The rapid degradation of 

formaldehyde in the environment, combined with the understanding that formaldehyde is widely 

used by living organisms as a 1C source, support a conclusion that any environmental effects of 

formaldehyde, including effects on other plants and NTO’s, resulting from dicamba-treated DT 

soybean would be negligible. 

Humans are also constantly exposed to low levels of formaldehyde. Human exposure to 

formaldehyde is primarily due to indoor and occupational air exposures (USHHS-ATSDR, 1999). 

Formaldehyde is also found in a variety of consumer products such as cosmetics and paints, often as 

an antimicrobial agent, and is used extensively in urea-formaldehyde “slow-release” fertilizer 

formulations and adhesives (USHHS-ATSDR, 1999). Indoor formaldehyde air concentrations are 

 

247 Calculation based on an assumption that the entire 0.56 kg/ha (0.5 lb/acre a.e.) application of dicamba to 

MON 87708 soybean at the V3 growth stage is intercepted by the soybean plants, is instantaneously and completely 

absorbed, and then instantaneously metabolized by the DMO enzyme. Complete demethylation of 560 g (2.5 mol)/ 

ha dicamba would yield 2.5 mol/ha formaldehyde. Above-ground biomass of V3 plants is estimated at 2 metric 

tons/ha, and results in 37.5 mg/kg formaldehyde in plants. For dicamba applications at R1 growth stage, the crop 

biomass is estimated to be 4.5 metric tons/ha, and level of formaldehyde produced in plants is 16.7 mg/kg.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 907 of 946

generally significantly higher than outdoor air concentrations (USHHS-ATSDR, 1999) as a result of 

combustion (cooking, heating, tobacco use) and the emission of formaldehyde from a variety of 

construction materials (e.g., particle board, plywood or foam insulation) as well as permanent press 

fabrics (clothing or draperies) (US CPSC, 1997). Formaldehyde present in outdoor air results from a 

number of sources, and levels of formaldehyde are generally higher in urban areas than in rural areas 

(WHO-IPCS, 1989). Direct contributions of formaldehyde to the atmosphere (i.e., those in the 

form of formaldehyde itself) from man-made sources are present, but are generally considered to be 

small relative to natural sources or indirect production of formaldehyde in the atmosphere (WHO, 

2002). Formaldehyde is rapidly consumed in the atmosphere through direct photolysis or by 

oxidation with hydroxyl or nitrate radicals (USHHS-ATSDR, 1999).

The National Toxicology Program (NTP) 12th Report on Carcinogens has reclassified formaldehyde 

as a known human carcinogen (USHHS-NTP, 2011). However, the relevant route of exposure for 

this health risk is from repeated inhalation of concentrated levels associated with indoor or 

occupational environments. As previously discussed, formaldehyde may only be released by plants 

in very small quantities and under certain conditions. Any incremental exposure to formaldehyde 

associated with the application of dicamba to DT soybean would occur outdoors, would be minimal, 

and also would be transient in nature. Therefore human safety concerns of formaldehyde released 

from dicamba treated DT soybean are considered to be negligible. USHHS-NTP (2011) has already 

stated that there is no evidence to suggest that dietary intake of formaldehyde is important. In 

addition, commodity soybean seed is not directly consumed by humans, and would be processed 

into food products, limiting potential exposure to humans to any formaldehyde in dicamba-treated 

DT soybean seed.

H.1.2.4. Summary of Findings

Trace amounts of MON 87708 DMO and dicamba reaction products are likely to be present in food 

and feed generated from DT soybean. Substantial analyses of the safety of these compounds have 

revealed no evidence of toxicity or allergenicity. These analyses suggest that the presence of DT 

soybean in human food and animal feed presents negligible risks. 

H.1.3. Dicamba-Tolerant Soy Presence in Food or Animal Feed

Monsanto intends to market DT soybean for the same commercial purposes as current transgenic 

and non-transgenic soybean varieties. Soybean seeds are processed primarily into oil and meal.

Soybean oil constitutes nearly 70% of consumption of edible fats and oils in the United States, and 

is the second largest source of vegetable oil worldwide. Soybean products are also used as human 

foods and sources of food ingredients.

Soybean meal is the predominant use of soybeans in animal feed and is the most common 

supplemental protein source in U.S. livestock and poultry rations due to its nutrient composition, 

availability, and price. Soybean forage is occasionally used in animal feed.

Thus, the food and animal feed uses of soybean and its processed products remain the predominant 

uses of soybeans.
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In efforts to assess the human health, livestock, and wildlife risks of exposure to DT soybean, 

potential impacts from MON 87708 DMO and dicamba reaction products are evaluated in this 

report.

H.1.3.1. Probability of Presence

As discussed above, only the MON 87708 DMO is produced from the inserted DNA. In the 

expression level studies conducted by Monsanto, MON 87708 DMO was found in some amount in 

the leaf, root, forage, and seed of DT soybean. See Part 1.2.1.2. When exposed to dicamba, the 

MON 87708 DMO catalyzes the demethylation of dicamba to the non-herbicidal compound DCSA 

and formaldehyde. As a result, the probability of human and animal dietary exposure to at least 

trace levels of MON 87708 DMO, DCSA, and formaldehyde is high. 

H.1.3.2. Health Effects of MON 87708 DMO

H.1.3.2.1. Health Effects of MON 87708 DMO and Dicamba Reaction Products on 

Humans

As discussed above, both the MON 87708 DMO and dicamba reaction products have been assessed 

for safety for human consumption. See Part 1.2.3. These assessments examined the donor organism 

safety, the similarity of MON 87708 DMO to a common class of mono-oxygenases, the dicambaspecificity of MON 87708 DMO, potential allergenicity issues, MON 87708 DMO digestibility, and 

the toxicity of MON 87708 DMO and the dicamba reaction products.248 These assessments 

concluded that the food and feed products containing DT soybean or derived from DT soybean are 

as safe as soybean currently on the market for human consumption. 

Studies on the persistence of plant-derived native DNA and recombinant DNA in livestock have 

indicated that feed-ingested DNA fragments do survive in the terminal gastrointestinal (GI) tract 

and that uptake into the gut epithelium does occur (Sharma, 2006). However, recombinant DNA 

fragments were not found in visceral tissues, like the kidney. There is no evidence thus far to 

indicate that the recombinant DNA that encodes the inserted gene would be processed in a manner 

any differently from the endogenous feed-ingested genetic material. 

H.1.3.2.2. Health Effects of MON 87708 DMO and Dicamba Reaction Products on 

Livestock

Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DT soybean. This consultation did not 

identify biologically meaningful differences between the composition of DT soybean and 

conventional soy. As discussed above, MON 87708 DMO belongs to a common class of monooxygenases, regularly consumed by humans and animals. Additionally, MON 87708 DMO did not 

cause any adverse effects in mice, with a No Observable Adverse Effect Level (NOAEL) of 

 

248 The dicamba reaction byproducts are considered pesticidal substances under EPA regulations. Monsanto has submitted a 

regulatory submission to EPA requesting the establishment of a tolerance for the use of dicamba on MON 87708 soybean.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 909 of 946

140 mg/kg body weight (BW), the highest dose level tested. At the conclusion of the FDA 

consultation, FDA had no questions about the safety of DT soybean and for use in food or feed.

The dicamba reaction byproducts are considered pesticidal substances under EPA regulations. 

Monsanto has submitted a regulatory submission to EPA requesting the establishment of a tolerance 

for the use of dicamba on DT soybean.

H.1.3.2.3. Health Effects of MON 87708 DMO and Dicamba Reaction Products on Nonlivestock Animals (Wildlife)

No specific data or scientific literature were found relating to the health effects of MON 87708 

DMO on non-livestock animals. As discussed above, MON 87708 DMO belongs to a common 

class of mono-oxygenases, regularly consumed by humans and animals. Additionally, MON 87708 

DMO did not cause any adverse effects in mice, with a No Observable Adverse Effect Level 

(NOAEL) of 140 mg/kg body weight (BW), the highest dose level tested. 

There is no evidence that MON 87708 DMO or dicamba reaction products will exhibit adverse 

biological activity toward wildlife. Because use of DT soybean is compatible with conservation 

tillage practices, usage of DT soybean may have a positive impact on wildlife. Conservation tillage 

practices can have a positive impact on wildlife, including beneficial arthropods (Altieri, 1999; Landis 

et al., 2005; Towery and Werblow, 2010). Conservation tillage practices benefit biodiversity due to 

decreased soil erosion leading to improved surface water quality, retention of vegetative cover, crop 

residues serving as a food source, and increased populations of invertebrates which can serve as 

food sources to other organisms (Landis et al. 2005; Sharpe, 2010).

H.1.3.3. Summary of Findings

There is little evidence that MON 87708 DMO and dicamba reaction products have any direct toxic 

effect on livestock or any deleterious outcome on nutritional parameters. The information evaluated 

suggests that the presence of MON 87708 DMO and dicamba reaction products in human food and 

animal feed pose negligible risks to humans, livestock, and wildlife. 

H.2. Dicamba and Glufosinate-Tolerant Cotton

H.2.1. Introduction

The scope of this section covers how Dicamba and-Glufosinate-Tolerant cotton (“DGT Cotton”) 

could be present in human food and animal feed and the potential health impacts of that presence.

H.2.1.1. Cotton Biology and Usage

Cotton belongs to the genus Gossypium that currently has approximately 50 species which are widely 

cultivated in tropical and subtropical regions around the world (OECD, 2008; Percival et al., 1999). 

There are four cultivated species that were domesticated independently, two of which account for 

greater than 95% of world cotton production. Gossypium hirsutum (often called upland, American, 

Mexican, or Acala cotton) accounts for 90% and Gossypium barbadense (often called extra long-staple, 

Pima, and Egyptian cotton) accounts for 5% of world cotton production. Due to the utility of the 

fibers for the production of textiles, human selection pressure on cotton has altered the plant from 

essentially perennial shrubs or trees with small impermeable seeds and sparse hairs to a compact 
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annual row crop, yielding large, easily germinating seeds with white, thick, long, and strong fibers 

(Brubaker et al., 1999).

Cotton is a crop that produces two commodities: fiber and seed. The fiber is the more valuable 

product of the crop, normally accounting for approximately 85% of the value. For every 100 pounds 

of fiber produced by the cotton plant, it also produces about 162 pounds of cottonseed (NCCA, 

2010). Cottonseed is crushed for oil and meal used in both food products and in livestock feed.

The four cultivated species, which are widely cultivated across the entire globe, are comprised of two 

diploid species G. arboretum and G. herbaceum, which evolved from Africa and the Middle East, and 

two allotetraploid species G. barbadense and G. hirsutum, which evolved in the Americas (Brubaker et 

al., 1999).

Improved modern varieties of G. hirsutum and G. barbadense are currently cultivated in the southern 

U.S., with G. barbadense grown primarily in the western states of Arizona, California, New Mexico, 

and Texas; and G. hirsutum produced throughout the 17 states comprising the U.S. cotton growing 

region, commonly referred to as the Cotton Belt. G. hirsutum comprises the vast majority of U.S. 

cotton production with nearly 11 million acres planted and 18 million bales harvested, whereas G. 

barbadense varieties accounted for approximately 200,000 acres and half a million bales in 2010 

(USDA-NASS, 2011b). Commercial cotton, including G. hirsutum and G. barbadense, has a long 

history of agricultural production (Lee, 1984; USDA-AMS, 2001; USDA-NASS, 2012). Extralong 

staple lint from G. barbadense is segregated and classed separately from G. hirsutum and is sold at a 

premium (USDA-AMS, 2001). However, cottonseed and cottonseed by-products (e.g., oil and meal) 

are not generally distinguished by species (OECD, 2008; USDA-FAS, 2005).

The majority of the value of the producer’s cotton crop is based on the quality and quantity of the 

lint produced, and with the exception of contracted acres for planting seed production. Little 

consideration is given by growers to the disposition of the cottonseed and its by-products. Most of 

the world’s cotton production (116.40 million bales annually) is grown in China (30.5 million bales), 

India (26.4 million bales), United States (18.1 million bales), Pakistan (8.6 million bales) and Brazil 

(9.0 million bales). Figures are from the 2010/2011 cotton season (USDA-FAS, 2012). In 

2010/2011, the U.S. supplied over 14 million bales of the world’s cotton exports, accounting for 

approximately 40% of the total world export market for cotton (USDA-FAS, 2011). Cottonseed 

production currently results in approximately 10% of the world’s oilseed production (USDA-FAS, 

2010), and is exceeded by soybean (58%) and rapeseed (13%).

Cotton (Gossypium spp.) is grown in the U.S. across southern states where the climate is warmer and 

the season is longer. The total U.S. cotton acreage in the past 10 years has varied from 

approximately 9.15 to 15.77 million planted acres, with the lowest acreage recorded in 2009 and the 

highest in 2001. Average cotton yields have varied from 632 to 879 pounds per acre over this same 

time period. Total annual cotton production ranged from 12.19 to 23.89 million bales (480 

pounds/bale) over the past ten years. The variations observed in cotton acreage and production are 

driven by current market conditions, rather than agronomic considerations. According to data from 

USDA-NASS (USDA-NASS, 2011a), cotton was planted on approximately 11 million acres in the 

U.S. in 2010, producing approximately 18 million bales of cotton. The value of cotton production 

reached $7.32 billion in the U.S. in 2010 (USDA-NASS, 2011a).
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H.2.1.2. Conventional Cotton Crop

The G. hirsutum cotton variety used as the recipient for the DNA insertion to create DGT cotton 

was Coker 130, a non-transgenic, conventional, upland inbred variety developed by Coker Pedigreed 

Seed Co., commercialized in 1990 in the U.S. (Bowman et al., 2006).

H.2.1.3. Gene and Gene Product

Production of a GE organism involves integration of a DNA cassette that is novel to a host plant 

into the host plant’s genomic DNA, called a transformation event. The DNA construct contains all 

the genetic information needed to produce the new characteristic or trait and, in most instances, this 

includes production of a protein. DGT cotton contains a demethylase gene from Stenotrophomonas 

maltophilia that expresses a dicamba mono-oxygenase (DMO) protein to confer tolerance to dicamba 

herbicide. DMO protein rapidly demethylates dicamba to the herbicidally inactive metabolite 3,6-

dichlorosalicylic acid (DCSA). DCSA has been previously identified as a metabolite of dicamba in 

cotton, soybean, livestock, and soil.

DGT cotton also contains a bialaphos resistance (bar) gene from Streptomyces hygroscopicus that 

expresses the phosphinothricin N-acetyltransferase (PAT) protein to confer tolerance to glufosinate 

herbicide. PAT (bar)249 protein acetylates the free amino group of glufosinate to produce nonherbicidal N-acetyl glufosinate, a well-known metabolite in glufosinate-tolerant plants.

H.2.1.4. Herbicides

Dicamba was approved by the U.S. EPA for agricultural uses in 1967 (U.S. EPA, 2009). Dicamba is 

formulated as a stand-alone herbicide product and marketed by several companies under various 

trade names such as Banvel®, Clarity®, Diablo®, Rifle®, and Sterling®that are various salt 

formulations of dicamba. These dicamba products can be tank mixed with one or more active 

ingredients depending on the treated crop. For example, Clarity can be tank mixed with over 75 

herbicide products in labeled crops. Additionally, dicamba is formulated as a registered premix 

product with one or more other herbicide active ingredients such as glyphosate, 2,4-D, 

diflufenzopyr, atrazine, nicosulfuron, metsulfuron, primsulfuron, triazulfuron, rimsulfuron and 

halosulfuron. Dicamba herbicide (e.g., Clarity – diglycolamine (DGA) salt of dicamba) is currently 

labeled for weed control in soybean, corn, cotton, sorghum, wheat, barley, oats, millet, pasture, 

rangeland, asparagus, sugarcane, turf, grass grown for seed, conservation reserve programs, and 

fallow croplands. 

Dicamba-treated acreage has ranged from 17.4 to 36.3 million acres between 1990 and 2011. Usage 

of dicamba peaked during the period of 1994 through 1997, where 1994 was the peak year when 36 

million crop acres were treated with 9.4 million pounds of dicamba. Since then, the use of dicamba 

has steadily declined to 17.4 million treated acres with 2.7 million pounds applied in 2006. The 

reduction in dicamba use has been attributed to the competitive market introductions of 

 

249 PAT (bar) indicates the PAT protein encoded by the bar gene isolated from S. hygroscopicus. The pat 

gene from S. viridochromogenes also encodes a PAT protein that confers glufosinate tolerance.
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sulfonylurea herbicides (chlorsulfuron, metsulfuron-methyl, and thifensulfuron-methyl) in wheat, 

new broadleaf herbicide active ingredients in corn, and introduction of glyphosate-tolerant corn. 

More recently, however, dicamba treated acres have been on the rise and have increased by as much 

as 7.9 million acres from 2006 to 2011. Most of this increase has occurred in fallow, pastureland, 

sorghum, and cotton (preplant) (Monsanto 2012). Currently, 364,000 pounds of dicamba are applied 

pre-plant on cotton, although use would be expected to rise if DGT cotton is deregulated. See 

Appendix A for more details.

Glufosinate was approved by the U.S. EPA for agricultural uses in 1989 (U.S. EPA 2013). 

Glufosinate is a non-selective foliar herbicide that is used for preplant and postemergence control of 

grass and broadleaf weeds. Glufosinate is formulated as a stand-alone herbicide product and 

marketed under the trade names Liberty®, IgniteTM, Ignite®280, RelyTM 200, and Rely®280. All 

products contain either 1.67 or 2.34 lbs per gallon of glufosinate-ammonium. Glufosinate (Rely®280 

and Ignite®280) is used for postemergence weed control in canola, corn, cotton, and soybean 

varieties that are glufosinate-tolerant. Glufosinate may be used for weed control in non-glufosinatetolerant cotton when applied with a hood sprayer in-crop. It may also be applied as a preplant 

burndown application in commercial varieties of canola, corn, cotton, soybean, or sugar beet. In 

addition, glufosinate (Rely®200 and Rely®280) may be used for postemergence weed control in 

apples, berries, grapes, tree nuts, and applied for potato vine desiccation. Glufosinate products can 

be tank mixed with other active ingredients depending on the treated crop. For example, IgniteTM 

can be tank mixed with metolachlor or fluometuron for in-crop applications in glufosinate-tolerant 

cotton. However, reduced weed control has been observed when glufosinate is tank mixed with 

glyphosate (Dotray et al. 2011; Reed et al 2011; Reed et al. 2012). 

Glufosinate-treated acreage across all crops has steadily increased from 1.6 million acres in 1998 to 

7.0 million acres in 2011. Increased weed resistance is one factor responsible for the increased use 

of glufosinate (Robertson 2012). Glufosinate is currently labeled for in-crop application on 

glufosinate-tolerant cotton from emergence through early bloom growth stage at 0.402 to 0.530 lbs 

a.i. per acre, seasonal maximum of 1.59 lbs a.i. per acre (Bayer Crop Science 2007). The average 

application rate in cotton is 0.39 pounds of glufosinate per acre with an average of 1.5 applications 

per season. 

H.2.2. Dicamba-and-Glufosinate-Tolerant Cotton Hazard Identification

Cotton is grown in 17 states across the southern U.S. and in over 80 countries world-wide. Cotton is 

grown primarily for its fiber, but also produces seed which can be used as animal feed or processed 

to serve as an ingredients in human food and animal feed. Monsanto Company developed DGT 

cotton to be tolerant to the herbicides dicamba and glufosinate.

H.2.2.1. DGT Cotton Biology

DGT cotton contains dmo and bar expression cassettes that, when transcribed and translated, result 

in the expression of the MON 88701 DMO and PAT (bar) proteins, respectively. 

DMO is an enzyme that catalyzes the demethylation of dicamba into the nonherbicidal compound 

DCSA and formaldehyde (Chakraborty et al., 2005). DCSA is a known cotton, soybean, soil, and 

livestock metabolite whose safety has been evaluated by the EPA. Formaldehyde is found naturally 

in many plants at levels up to several hundred ppm.
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The mode-of-action for the PAT protein has been extensively assessed, as numerous glufosinatetolerant products including those in cotton, corn, soy, canola, sugarbeet and rice have been reviewed 

by the FDA and several other regulatory agencies (ILSI-CERA, 2011; OECD, 1999a; 2002). PAT, 

including the PAT (bar) protein produced in DGT cotton, is an enzyme classified as an 

acetyltransferase which acetylates glufosinate to produce non-herbicidal N-acetyl glufosinate. 

Glufosinate is a racemic mixture of the D- and L- forms of phosphinothricin, though only the Lform has herbicidal activity. The herbicidal activity of glufosinate results from the binding of Lphosphinothricin to glutamine synthetase (OECD, 1999b; 2002). Glutamine synthetase is 

responsible for the assimilation of ammonia generated during photorespiration. The binding of Lphosphinothricin to glutamine synthetase results in the inactivation of glutamine synthetase and a 

subsequent toxic build-up of ammonia within the plant, resulting in death of the plant 

(Manderscheid and Wild, 1986; OECD, 1999b; 2002; Wild and Manderscheid, 1984).

The PAT (bar) protein produced in DGT cotton acetylates the free amine group of the Lphosphinothricin form of glufosinate to produce non-herbicidal N-acetyl glufosinate. The acetylated 

glufosinate is unable to bind to glutamine synthetase and therefore does not disrupt 

photorespiration and avoids the build-up of ammonia. Therefore, the production of PAT (bar) 

protein in DGT cotton confers glufosinate herbicide tolerance through this mechanism.

Molecular characterization determined that DGT cotton contains one copy of the T-DNA at a 

single integration locus and all genetic elements are present. These data also demonstrated that DGT 

cotton does not contain detectable backbone sequences from the plasmid vector. The complete 

DNA sequence of the insert and adjacent genomic DNA sequences in DGT cotton confirmed the 

integrity of the inserted dmo and bar expression cassettes. Molecular characterization analysis also 

demonstrated that the insert in DGT cotton has been maintained over five consecutive generations 

of breeding, thereby confirming the stability of the insert. Furthermore, results from segregation 

analyses show inheritance and stability of the insert were as expected across multiple generations, 

which corroborates the molecular insert stability analysis determination that the DGT cotton TDNA resides at a single chromosomal locus within the cotton genome.

H.2.2.1.1. Characterization of DGT Cotton

The safety assessment of crops derived through biotechnology includes characterization of the 

physicochemical and functional properties of the protein(s) produced from the inserted DNA, and 

confirmation of the safety of the protein(s). For the safety data generated using E. coli-produced 

protein(s) to be applied to plant-produced protein(s), the equivalence of the plant- and E. coliproduced proteins must be assessed. For DGT cotton the physicochemical and functional 

characteristics of the MON 88701 DMO and MON 88701-produced PAT (bar) proteins were 

determined and each was shown to be equivalent to its respective E. coli-produced protein. 

The MON 88701 DMO protein purified from cottonseed of DGT cotton was characterized and the 

equivalence of the physicochemical and functional properties between the MON 88701 DMO and 

the E. coli-produced MON 88701 DMO proteins was established using a panel of analytical tests: 1)

the identity could not be confirmed by N-terminal sequence analysis; however, MALDI-TOF MS 

analysis of peptides derived from tryptic digested MON 88701 DMO established the N-terminal 

sequence of MON 88701 DMO; 2) MALDI-TOF MS analysis yielded peptide masses consistent 

with the expected peptide masses from the theoretical trypsin digest of the MON 88701 DMO 

sequence; 3) MON 88701 DMO protein was detected on a western blot probed with antibodies 
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specific for DMO protein and the immunoreactive and physiochemical properties of the MON 

88701 DMO and E. coli-produced MON 88701 DMO proteins were shown to be equivalent; 4) the 

electrophoretic mobility and apparent molecular weight of the MON 88701 DMO and E. coliproduced MON 88701 DMO proteins were shown to be equivalent; 5) glycosylation status of MON 

88701 DMO and E. coli-produced MON 88701 DMO proteins were determined to be equivalent; 

and 6) functional activity of the MON 88701 DMO and the E. coli-produced MON 88701 DMO 

proteins were demonstrated to be equivalent (Monsanto 2012).

The MON 88701-produced PAT (bar) protein purified from cottonseed of DGT cotton was 

characterized and the equivalence of the immunoreactive and physicochemical characteristics and 

functional activity between the MON 88701- and the E. coli-produced PAT (bar) proteins was 

established using a panel of analytical tests: 1) N-terminal sequence analysis of the MON 88701-

produced PAT (bar) protein established identity; 2) MALDI-TOF MS analysis yielded peptide 

masses consistent with the expected peptide masses from the theoretical trypsin digest of the MON 

88701-produced PAT (bar) sequence; 3) MON 88701-produced PAT (bar) protein was detected on a 

western blot probed with antibodies specific for PAT (bar) protein and the immunoreactive 

properties of the MON 88701-produced and E. coli-produced PAT (bar) proteins were shown to be 

equivalent; 4) the electrophoretic mobility and apparent molecular weight of the MON 88701-

produced and E. coli-produced PAT (bar) proteins were shown to be equivalent; 5) glycosylation 

status of MON 88701- and E. coli-produced MON 88701 PAT (bar) proteins were determined to be 

equivalent; and 6) functional activity of the MON 88701- and E. coli-produced PAT (bar) proteins 

were demonstrated to be equivalent. (Monsanto 2012)

Taken together, these data provide a detailed characterization of the MON 88701 DMO and PAT 

(bar) proteins and establish their respective equivalence to E. coli-produced MON 88701 DMO 

protein and E. coli-produced PAT (bar) protein. This equivalence justifies the use of the E. coliproduced proteins as test substances in the protein safety studies.

H.2.2.1.2. Expression Levels of MON 88701 DMO and PAT (bar) Proteins in DGT Cotton

MON 88701 DMO and PAT (bar) protein levels in various tissues of DGT cotton relevant to the 

risk assessment were determined by a validated enzyme-linked immunosorbent assay (ELISA). 

Tissues of DGT cotton were collected from four replicate plots planted in a randomized complete 

block field design during the 2010 growing season from the following eight field sites in the U.S.: 

Arkansas (ARTI), Georgia (GACH), Kansas (KSLA), Louisiana (LACH), North Carolina (NCBD), 

New Mexico (NMLC), South Carolina (SCEK), and Texas (TXPL). DGT cotton plots were treated 

at the 3-5 leaf stage with glufosinate herbicide at the label rate (0.5 lbs active ingredient [a.i.]/acre) 

and at the 6-10 leaf stage with dicamba herbicide at the proposed label rate (0.5 lbs acid equivalent 

[a.e.]/acre). The field sites were representative of cotton-producing regions suitable for commercial 

production. Seed, pollen, root, and overseason leaf (OSL-1 through OSL-4) tissue samples were 

collected from each replicated plot at all field sites. (Monsanto 2012)

MON 88701 DMO protein levels were determined in all seven tissue types. The results obtained 

from ELISA are summarized in Table H-5 and the details of the materials and methods are 

described in Appendix D to the Monsanto petition. (Monsanto 2012). Due to a limited amount of 

tissue, moisture content was not measured for pollen; therefore, pollen is reported on a fresh weight 

(fw) basis only. MON 88701 DMO protein levels in DGT cotton across tissue types ranged from 

<LOD to 410 μg/g dw. The mean MON 88701 DMO protein levels were determined across eight 
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sites, with the exception of OSL-1 (7 sites) and OSL-4 (7 sites). Samples <LOD were not included 

in mean determinations. The mean MON 88701 DMO protein levels were highest in leaf (ranging 

from OSL-2 and OSL-3 at 240 μg/g dw, OSL-4 at 230 μg/g dw to OSL-1 at 180 μg/g dw), 

followed by root at 43 μg/g dw, seed at 21 μg/g dw, and pollen at 14 μg/g fw.
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Table H-4. Summary of MON 88701 DMO Protein Levels in Tissues from DGT Cotton

Grown in 2010 U.S. Field Trials

Tissue 

Type1

Development 

Stage2

Days After 

Planting 

(DAP)

PAT (bar) 

Mean (SD) 

Range

(μg/g fw)3

PAT (bar) 

Mean (SD) 

Range

(μg/g dw)4

LOQ/LOD

(μg/g fwt)6,7

OSL-1

2-4 leaf 14-25 27 (7.6)

13 – 42

180 (52)

110 – 280 0.168/0.313

OSL-2 4-7 leaf 25-37 41 (12)

19 – 65

240 (69)

110 – 380

0.168/0.313

OSL-3 9 leaf – Full flower 35-99 52 (17)

24 – 97

240 (75)

91 – 410

0.168/0.313

OSL-4

Cutout – Full 

flower 70-121 57 (18)

0.70 – 91

230 (59)

2.8 – 310

0.168/0.313

Root 50% open flowerFull flower 70-121 14 (3.7)

8.2 – 21

43 (12)

26 – 72 0.168/0.313

Pollen 50% open flower 

– Full flower 68-99 14 (28)

0.31 – 110

NA (NA)

NA 0.043/0.125

Seed Maturity 148-183 20 (4.6)

8.2 – 29

21 (5.0)

8.9 – 33 0.059/0.313

1OSL= over-season leaf. Seed = black seed (ginned and delinted).

2The crop development stage each tissue was collected (Ritchie et al., 2007).

3Protein levels are expressed as the arithmetic mean and standard deviation (SD) as microgram (μg) of protein per gram 

(g) of tissue on a fresh weight basis (fw). The means, SD, and ranges (minimum and maximum values) were calculated 

for each tissue across all sites (n=32, except OSL-3 n=31 due to one sample <LOD, OSL-1 and OSL-4 n=28 due to 

missed sample collections, and pollen n=29 due to two samples expressing <LOD and one being inconclusive).

4Protein levels are expressed as μg/g on a dry weight (dw) basis. The dry weight values were calculated by dividing the 

μg/g fw by the dry weight conversion factors obtained from moisture analysis data. NA= Not Applicable.

5LOQ=limit of quantitation; LOD=limit of detection. Note: In the DGT cotton petition (Monsanto 2012) the column 

heading was incorrectly labeled LOQ/LOD.
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PAT (bar) protein levels were determined in all seven tissue types. The results obtained from ELISA 

are summarized in Table H-6 and the details of the materials and methods are described in 

Appendix D to the Monsanto petition. (Monsanto 2012). Due to a limited amount of tissue, 

moisture content was not measured for pollen; therefore, pollen is reported on a fresh weight (fw) 

basis only. PAT (bar) protein levels in DGT cotton across tissue types ranged from <LOQ to 10 

μg/g dw. The mean PAT (bar) protein levels were determined across eight sites, with the exception 

of OSL-1 (7 sites) and OSL-4 (7 sites). Samples <LOD were not included in mean determinations. 

The mean PAT (bar) protein levels were highest in seed at 6.6 μg/g dw, followed by leaf (ranging 

from OSL-2 at 6.4 μg/g dw to OSL-4 at 3.2 μg/g dw), root at 1.8 μg/g dw, and pollen at 0.56 μg/g 

fw.
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Table H-5. Summary of PAT (bar) Protein Levels in Tissues from DGT Cotton Grown in 

2010 U.S. Field Trials

Tissue 

Type1

Development 

Stage2

Days After 

Planting 

(DAP)

PAT (bar) 

Mean (SD) 

Range

(μg/g fw)3

PAT (bar) 

Mean (SD) 

Range

(μg/g dw)4

LOQ/LOD

(μg/g fwt)6,7

OSL-1 2-4 leaf 14-25 0.84 (0.21)

0.46 - 1.4

5.5 (1.5)

3.7 – 9.1

0.162/0.188

OSL-2 4-7 leaf 25-37 1.1 (0.26)

0.68 – 1.6

6.4 (1.4)

3.8 – 9.4

0.162/0.188

OSL-3 9 leaf – Full 

flower

35-99 1.0 (0.34)

0.34 – 1.7

4.8 (2.0)

1.3 - 10

0.162/0.188

OSL-4 Cutout – Full 

flower

70-121 0.78 (0.29)

0.42 – 1.7

3.2 (1.2)

2.0 – 6.7

0.162/0.188

Root 50% open 

flower-Full 

flower

70-121 0.56 (0.18)

0.27 – 0.89

1.8 (0.75)

0.93 – 3.3

0.162/0.188

Pollen 50% open 

flower – Full 

flower

68-99 0.56 (0.24)

0.27 – 0.90

NA (NA)

NA

0.021/0.188

Seed Maturity 148-183 6.1 (0.95)

4.8 – 8.8

6.6 (1.1)

5.2 – 9.6

0.032/0.188

1OSL= over-season leaf. Seed = black seed (ginned and delinted).

2The crop development stage each tissue was collected (Ritchie et al., 2007).

3Protein levels are expressed as the arithmetic mean and standard deviation (SD) as microgram (μg) of protein per gram 

(g) of tissue on a fresh weight basis (fw). The means, SD, and ranges (minimum and maximum values) were calculated 

for each tissue across all sites (n=32, except OSL-1 n=28 due to missed sample collections, OSL-4 n=27 due to missed 

sample collections and one sample expressing <LOD, OSL-3 n=31 due to one sample expressing <LOD, and pollen 

n=6 due to 26 samples expressing <LOQ).

4Protein levels are expressed as μg/g on a dry weight (dw) basis. The dry weight values were calculated by dividing the 

μg/g fw by the dry weight conversion factors obtained from moisture analysis data. NA= Not Applicable.

5LOQ=limit of quantitation; LOD=limit of detection.

H.2.2.1.3. Compositional Assessment

Monsanto conducted detailed analyses on nutrient and anti-nutrient levels in DGT cottonseed from 

plants treated with dicamba and glufosinate, reported above, and plants not treated with dicamba or 

glufosinate. See petition (Monsanto 2012). Component levels for DGT cotton were compared to 

levels in the conventional control. The analytes evaluated are consistent with those identified by the 

OECD as important to understanding the safety and nutrition of new varieties of biotechnologyderived cotton (OECD, 2009). These compositional comparisons were made by analyzing the aciddelinted cottonseed harvested from plants grown at each of eight field sites in the U.S. during the 

2010 field season. Composition analyses of all samples, conducted in accordance with OECD 

guidelines, were performed for nutrients including proximates (ash, carbohydrates, and calories by 
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calculation, moisture, protein, and fat), fibers (ADF, CF, NDF, and TDF), amino acids, fatty acids 

(C8-C22), minerals (calcium, copper, iron magnesium, manganese, phosphorus, potassium, sodium, 

and zinc), and vitamin E. The anti-nutrients assessed in this analysis included total and free gossypol 

and cyclopropenoid fatty acids (dihydrosterculic, malvalic, and sterculic). These analyses also 

included measurements of the same nutrients and anti-nutrients in conventional commercial cotton 

varieties, known as reference varieties, to provide data on natural variability of each compositional 

component analyzed. All cotton plants including DGT cotton, the conventional control, and the 

conventional commercial reference varieties, were treated with maintenance pesticides as necessary 

throughout the growing season. In addition, DGT cotton plots were treated at the 3-5 leaf stage 

with glufosinate herbicide at the label rate (0.5 lbs a.i./acre) and at the 6-10 leaf stage with dicamba 

herbicide at the label rate (0.5 lbs a.e./acre).

For DGT cotton compared to the conventional control, the combined-site analysis of cottonseed 

showed no statistically significant differences (p<0.05) between nutrient and anti-nutrient 

components of DGT cotton and the control for 30 (57.7%) of the 52 mean value comparisons. 

Cottonseed nutrient component differences included mean values for five proximates (ash, calories, 

carbohydrates, moisture, and total fat), three types of fiber (ADF, NDF, and TDF), three amino 

acids (arginine, methionine, and proline), two fatty acids (14:0 myristic acid and 18:2 linoleic acid), 

five minerals (calcium, magnesium, manganese, potassium and zinc), and vitamin E. Cottonseed 

anti-nutrient component differences included mean values for dihydrosterculic acid, free and total 

gossypol. All nutrient and anti-nutrient component differences observed in the combined-site 

statistical analysis, whether reflecting increased or decreased DGT cotton mean values with respect 

to the conventional control, were 14.09% or less. Mean values for all significantly different nutrient 

and anti-nutrient components from the combined-site analysis of DGT cotton, with the exception 

of methionine, were within the 99% tolerance interval established from the conventional, 

commercial reference varieties grown concurrently in the same trial. All combined-site mean values, 

including methionine, and individual site mean values of DGT cotton for all nutrient and antinutrient components were within the context of the natural variability of commercial cotton 

composition as published in the scientific literature and/or available in the ILSI Crop Composition 

Database (ILSI, 2011).

Overall, for DGT cotton mean component values observed to be significantly different from those 

of the conventional control, the differences with the control were generally shown to be of small 

relative magnitudes. All DGT cotton mean component values in the combined-site analysis, with the 

exception of methionine, were within the 99% tolerance interval established from the conventional 

commercial references varieties grown concurrently and at the same field sites. All combined-site 

mean values including methionine and individual site mean values of DGT cotton for all nutrient 

and antinutrient components were within the context of the natural variability of commercial cotton 

composition as published in the scientific literature and/or available in the ILSI Crop Composition 

Database (ILSI, 2011).

For DGT cotton treated with dicamba and glufosinate, compared to the conventional control, most 

of the combined-site differences were not reproducible among the individual sites, with the 

exception of ash and calcium; however, all of the combined-site component values were within the 

range of values reported in the scientific literature and/or in the ILSI Crop Composition Database. 

Additionally, the concentrations of key nutrients and anti-nutrients of cottonseed from DGT cotton 

that was not treated with dicamba or glufosinate were also analyzed. Results from this analysis were 

similar to those of the dicamba and glufosinate treated analysis. Based on the results of this 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 920 of 946

composition analysis, it is concluded that cottonseed from DGT cotton is compositionally 

equivalent to conventional cotton and therefore the food and feed safety and nutritional quality of 

this product is comparable to that of the commercially cultivated cotton.

The processing of DGT cotton is not expected to be any different from that of conventional cotton. 

As described in this section, detailed compositional analyses of key components of DGT cotton 

have been performed and have demonstrated that DGT cotton is compositionally equivalent to 

conventional cotton. Additionally, the mode of action of the MON 88701 DMO and PAT (bar) 

proteins is well understood, and there is no reason to expect interactions with important nutrients or 

known anti-nutrients that are present in cotton. Therefore, when DGT cotton and its progeny are 

used on a commercial scale as a source of food or feed, these products are not expected to be 

different from the equivalent foods or feeds originating from commercially cultivated cotton.

H.2.2.1.4. MON 88701, PAT (bar), and Gene Sequence Detection

Monsanto has committed to best industry practices on seed quality assurance and control to ensure 

the purity and integrity of DGT cotton seed. Before commercializing DGT cotton in any country, 

Monsanto has pledged to make a DGT cotton detection method available to cotton producers, 

processors, and buyers.

H.2.2.1.4.1. MON 88701 DMO, PAT (bar), and Gene Sequence Detection Methods

Methods for detecting GE materials range in their limits of detection. In many situations, a test will 

be required that not only detects the presence of GE material, but also measures the amount of GE 

content in the sample. All testing methodologies detect either the inserted DNA or the expressed 

protein resulting from the inserted DNA. The major detection methods for transgenic proteins are 

Enzyme Linked Immunosorbent Assays (ELISAs), and make use of the properties of antibodies. 

ELISAs are easy to use, robust and cheaper than DNA detection methods but generally less 

sensitive (Griffiths et al., 2002). In contrast to protein detection assays, assays designed to detect 

transgenic DNA are more sensitive. The most commonly used DNA amplification method is the 

Polymerase Chain Reaction (PCR), though there are other amplification methods to suit specific 

applications.

For each testing method, a Limit of Detection (LOD) is defined to show the sensitivity of the 

method. For example, a method with an LOD of 1 percent (w/w) for GT soy would be able to 

detect GT soy in a batch of soy flour when present as 1 percent (w/w) of the total soy flour 

(Griffiths et al., 2002). It is important to note that this LOD value written in an abbreviated form 

means the LOD for GT soy is 1 percent (w/w) of total soy flour if the product is comprised of 100 

percent soy (Griffiths et al., 2002). For food products containing several ingredients, estimation of 

the LOD is less reliable. Using the previous example, if the 1 percent (w/w) GE soy flour were used 

as a baking ingredient in cake, the soy flour may make up only 0.5 percent (w/w) of the total cake 

ingredients. The GE soy would thus be only 0.005 percent (w/w) of the total sample, which would 

be well below the LOD for this method (Griffiths et al., 2002). The LOD is normally defined on a 

percent (w/w) basis, the actual measurement of GE ingredients is based on either DNA or protein 

and this DNA- or protein-based measurement is not necessarily directly transferable to a percent 

(w/w) measurement (Griffiths et al., 2002). Some highly processed foods contain no traces of DNA 

and/or protein. In these cases, there is no analytical method available to identify whether these 

products are derived from GE materials.
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H.2.2.1.4.2. Labeling Standards

In the United States, foods derived from GE plants are not required to indicate on the food label 

that they were derived from plants produced through the use of biotechnology. While Australia has 

a tolerance level of 1 percent unintended GE material, other countries such as Japan and Korea 

currently have a higher tolerance level of 5 percent (Griffiths et al., 2002). On the other hand, the 

European Commission (EC), on behalf of the European Union (EU), has proposed new legislation 

to drop the threshold for the presence of unintended GE content from 1 percent to 0.5 percent. 

The EU is also planning to adopt a process-based rather than the product-based GE food labeling 

approach, so that any product derived from gene technology would have to be labeled, even if the 

novel DNA and/or protein were completely removed. The commercial feed producer is required by 

EU legislation to label feed containing GE feed ingredients. At present, European Market 

Regulations 2003/1829/EC and 2003/1830/EC govern the use of GE ingredients intended for 

food, feed, and food additives. Threshold labeling at 9 g/kg (0.9 percent) for the unintended 

presence of approved GE material and 5 g/kg for GE materials not approved in Europe is required 

(Bakke-McKellep et al., 2007). In addition, a 0.5 percent labeling threshold has been mandated for 

GE crops that have been given a favorable risk assessment but are not yet approved within the EU. 

Unapproved varieties are managed with zero tolerance (Alexander et al., 2007). Products such as 

milk, meat, and eggs, and that are derived from livestock fed transgenic feeds are exempt from EUlabeling laws. Currently, only the EU and Switzerland have labeling regulations specifically pertaining 

to GE feed (Griffiths et al., 2002; Alexander et al., 2007; ISAAA, 2005).

H.2.2.1.4.3. Detection in Food Products

There is some literature available on the detection and quantification of GE material in various 

foods. In an Australian monitoring study (Griffiths et al., 2002), the GT trait was detected in soy 

flour, soy protein isolate, soy milk, snack foods, biscuits, powdered bread, and corn flour as 

illustrated in figure H-7 below.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 922 of 946

Figure H-2: Australian Detection of Genetically Engineered Material in Various Foods 

(Griffiths et al., 2002)

H.2.2.1.4.4. Detection of MON 88701 DMO, PAT (bar) and Gene Sequence in 

Downstream Animals

The European Food Safety Authority (EFSA) has reported that a large number of experimental 

studies have shown that recombinant DNA consumed by livestock has not been subsequently 

detected in tissues, fluids, or edible products of these farm animals (EFSA 2007). DNA has always 

been present in food and, upon consumption, is quickly degraded by restriction nucleases present in 

the gastrointestinal tract of humans and animals to nucleic acids. According to the U.S. FDA 

(1992), nucleic acids are present in the cells of every living organism, do not raise concerns as a 

component of food, and are generally recognized as safe. Results from an International Life 

Sciences Institute (ILSI) workshop on safety considerations of DNA in food were reported (Jonas et 

al., 2001) and confirmed that: 1) all DNA, including recombinant DNA, is composed of the same 

four nucleotides; 2) there are no changes to the chemical characteristics or the susceptibility to 

degradation by chemical or enzymatic hydrolysis of recombinant DNA as compared to 

non-recombinant DNA; and 3) there is no evidence that DNA from dietary sources has ever been 

incorporated into the mammalian genome. 

As described by the European Food Safety Authority (EFSA) in 2007 the fate of recombinant DNA 

from genetically engineered plants or resultant proteins are dependent on the following four factors:

 the fate of the recombinant DNA and protein during the feed processing and ensilaging;
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 923 of 946

 the fate of the recombinant DNA and protein in the gastrointestinal tract of animals fed 

with the GE feed;

 the potential absorption of the digested pieces of DNA or protein into animal 

tissues/products; and 

 the potential of biological functionality of absorbed DNA and protein fragments. 

No study has found that mechanical treatment (e.g., baling, chopping, processing) of animal feed has 

effect on DNA stability (EFSA). Digestion in the gut generally causes DNA and protein to be 

broken down to the original nucleotides and amino acids respectively. The inserted DNA and 

protein expressed from the inserted DNA are not expected to be digested in any different manner 

simply because they are present in the food due to the use of biotechnology.

For example, in field tests, CP4 EPSPS, the inserted gene sequence in glyphosate-tolerant (GT) 

soybeans, was found in GT soybean at 0.1 percent in chicken feed (Ash et al., 2003) by an ELISA 

method; no detectable amounts of CP4 EPSPS protein were in whole egg, egg albumen, liver, or 

feces of the chickens fed GT soybeans.

Conventional PCR/Southern Blot and an ELISA method were utilized to determine if transgenic 

DNA or protein were detectable in pigs fed GT soybeans (Jennings et al., 2003). The authors report 

that there was an absence of detectable levels of fragments of either transgenic DNA or protein. By 

contrast Sharma (2006) reported detection of transgenic DNA in intestinal tissue.

Quantitative real-time PCR and conventional PCR were used to evaluate GT canola cp4 epsps 

transgene in the intestines, rumen, or feces of sheep feed canola meal (Alexander et al., 2004). 

Digestion of plant material and release of tDNA (including transgenic DNA) can occur in the small 

intestine of sheep. The free transgenic DNA is rapidly degraded at neutral pH in small intestine 

duodenal fluid, thus reducing the likelihood that intact transgenic DNA would be available for 

absorption through the Peyer’s Patches further down in the distal ileum of the small intestine 

(Alexander et al., 2004).

The persistence of plant-derived recombinant DNA in sheep and pigs fed GE (GT) canola was 

assessed by Sharma et al. (2006) utilizing PCR and Southern hybridization analysis of DNA 

extracted from digesta, GI tract tissues, and visceral organs. This study confirmed that DNA 

fragments ingested in feed do survive to the terminal GI tract and that uptake into gut epithelial 

tissues does occur. A very low frequency of transmittance to visceral tissue was confirmed in pigs, 

but not in sheep. There was no evidence to suggest that recombinant DNA would be processed in 

the gut in any manner different from endogenous feed-ingested genetic material.

A study by Netherwood et al. (2004) and the discussion by Heritage (2004) address the finding by 

Netherwood et al. of evidence of low-frequency EPSPS gene transfer from genetically engineered 

soya to the microflora of the small bowel. However, the microflora contained only fragments 

EPSPS; the full length gene was not detected, and it could not be determined whether it was the 

bacteria themselves that contained the fragments.
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H.2.2.2. DGT Cotton Safety Assessment

H.2.2.2.1. MON 88701 DMO and PAT (bar) Safety Assessment

FDA enforces laws regarding the safety and labeling of food and feed. In 2013 Monsanto 

completed a voluntary consultation with FDA regarding the food and feed safety of DGT cotton. 

See Appendix I of this Environmental Report. FDA considers a consultation to be completed when 

all safety and regulatory issues are resolved. See Appendix I of this Environmental Report. As part 

of the consultation, Monsanto discussed its finding that the MON 88701 DMO belongs to a 

common class of mono-oxygenases present in bacteria and plants currently widely prevalent in the 

environment and consumed, and that PAT (bar) is well understood and included in existing 

deregulated glufosinate-tolerant crops. Available data demonstrate that harvested seed is as safe as 

conventional cotton seed for food and feed uses.

H.2.2.2.1.1. DMO Donor Organism Safety

The dmo gene is derived from the bacterium Stenotrophomonas maltophilia (Palleroni and Bradbury, 

1993). S. maltophilia is ubiquitous in the environment and is found associated with the rhizosphere of 

plants. S. maltophilia can be found in a variety of foods and feeds, and is widespread in the home 

environment (Berg et al., 1999; Denton and Kerr, 1998; Echemendia, 2010). Exposure to S. 

maltophilia is incidental to its presence in food. It has been isolated from “ready to eat” salads, 

vegetables, frozen fish, milk, and poultry (Qureshi et al., 2005; Ryan et al., 2009). S. maltophilia can be 

found in healthy individuals without causing any harm to human health (Denton et al., 1998) and 

infections caused by S. maltophilia are extremely uncommon (Cunha, 2010). Strains have been found 

in the transient flora of hospitalized patients as a commensal organism (Echemendia, 2010) and, 

similar to the indigenous bacteria of the gastrointestinal tract, S. maltophilia can be an opportunistic 

pathogen (Berg, 1996). As such, S. maltophilia is of low virulence in immuno-compromised patients 

where a series of risk factors (severe debilitation, the presence of indwelling devices such as 

ventilator tubes or catheters, for prolonged periods of time and prolonged courses of antibiotics) 

must occur for colonization by S. maltophilia in humans (Ryan et al., 2009). Therefore, infections by 

S. maltophilia almost exclusively occur in hospital settings, in which case they are only present in a 

minimal percentage of infections (Ryan et al., 2009). Finally, S. maltophilia has not been reported to 

be source of allergens.

The ubiquitous presence of S. maltophilia in the environment, the presence in healthy individuals 

without causing infections, the incidental presence in foods without any adverse safety reports, and 

the lack of reported allergenicity establishes the safety of the donor organism.

H.2.2.2.1.2. MON 88701 DMO Belongs to a Common class of Mono-Oxygenases

MON 88701 DMO is classified as an oxygenase. Oxygenases are enzymes that incorporate one or 

two oxygen atoms into substrates and are widely distributed in many universal metabolic pathways 

(Harayama et al., 1992). Within this large enzymatic class are mono-oxygenases that incorporate a 

single oxygen atom as a hydroxyl group with the concomitant production of water and oxidation of 

NAD(P)H (Harayama et al., 1992). Non-heme iron oxygenases, where iron is involved in the 

catalytic site, are an important class of oxygenases. Within this class are Rieske oxygenases, which 

contain a Rieske iron-sulfur [2Fe-2S] cluster. All Rieske non-heme iron oxygenases contain two 

catalytic domains, a non-heme iron domain (nh-Fe) that is a site of oxygen activation, and a Rieske 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 925 of 946

[2Fe-2S] domain (Ferraro et al., 2005). MON 88701 DMO belongs to this class of oxygenases which 

are found in diverse phyla ranging from bacteria to plants (Ferraro et al., 2005; Schmidt and Shaw, 

2001).

As discussed previously, the crystal structure of a DMO has been solved (D'Ordine et al., 2009; 

Dumitru et al., 2009). The crystallography results demonstrated that, similar to all Rieske non-heme 

iron oxygenases, DMO contains two catalytically important and highly conserved domains; a 

mononuclear non-heme iron domain (nh-Fe) that is a site of oxygen activation, and a Rieske [2Fe2S] domain (D'Ordine et al., 2009; Dumitru et al., 2009; Ferraro et al., 2005). The amino acids 

binding the non-heme iron and those that constitute the Rieske [2Fe-2S] domain in the DMO 

protein are also highly conserved in these plant proteins, as is their spatial orientation (D'Ordine et 

al., 2009; Ferraro et al., 2005). Rieske domains are ubiquitous in numerous bacterial and plant 

proteins like the iron-sulfur protein of the cytochrome bc1 complex, chloroplast cytochrome b6/f 

complex, and choline mono-oxygenases (Breyton, 2000; Darrouzet et al., 2004; Gray et al., 2004; 

Hibino et al., 2002; Rathinasabapathi et al., 1997; Russell et al., 1998). The presence of two 

conserved domains, a Rieske [2Fe-2S] domain and a mononuclear iron domain, suggests that all 

Rieske type non-heme iron oxygenases share the same reaction mechanism, by which the Rieske 

domain transfers electrons from the ferredoxin to the mononuclear iron to allow catalysis 

(Chakraborty et al., 2005; Dumitru et al., 2009; Ferraro et al., 2005). The structure and mechanistic 

homologies are further evidence of the evolutionary relatedness of all Rieske non-heme iron 

oxygenases to each other (Nam et al., 2001; Rosche et al., 1997; Werlen et al., 1996). Additionally, a 

FASTA alignment search of publicly available databases using the MON 88701 DMO protein 

sequence as a query yielded homologous sequences from many different species, predominantly 

bacteria, with amino acid sequence identity ranging up to approximately 42%. Alignments of MON 

88701 DMO with plant proteins revealed homologous oxygenases present in crops such as canola 

(Brassica napus), corn (Zea mays), pea (Pisum sativum), rice (Orysa sativa), and soy (Glycine max), 

which were determined to have sequence identities up to approximately 27%. The highest homology 

was observed to proteins that are involved in chlorophyll metabolism. Chlorophyllide A oxygenase 

(Accession number: ACG42449) is Rieske-type oxygenase that is required for the formation of 

chlorophyll b, which is present in all plants (Tanaka et al., 1998). Pheophorbide A oxygenase 

(Accession number: ABD60316) is also a Rieske-type oxygenase that plays a key role in the overall 

regulation of chlorophyll degradation in plants (Rodoni et al., 1997). Pheophorbide A oxygenase is 

constitutively present in all green tissues and, at slightly lower levels, in etiolated and nonphotosynthetic tissues including seeds (Yang et al., 2004). As a Rieske-type oxygenase, 

Pheophorbide A oxygenase is expected to have high degree of secondary and tertiary structure 

homology to similar structural elements in DMO as described above. The presence of these 

conserved structural domains in these plant proteins is further evidence that exposure to a structural 

homolog of MON 88701 DMO has occurred through consumption of these crops.

Therefore, MON 88701 DMO shares sequence identity and many catalytic domain structural 

similarities with a wide variety of oxygenases present in bacteria and plants currently widely 

prevalent in the environment and consumed, establishing that animals and humans are extensively 

exposed to these types of enzymes.

H.2.2.2.1.3. DMO is a Dicamba-Specific Mono-Oxygenase

DMO converts dicamba to DCSA. This demethylation is very specific to dicamba, where both the 

carboxylate moiety and the chlorine atoms help position the substrate at the active site of the 
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enzyme (D'Ordine et al., 2009; Dumitru et al., 2009). Crystallography studies of the substrate in the 

active site demonstrated that these chlorines function as steric “handles” that position the substrate 

in the proper orientation in the binding pocket (Dumitru et al., 2009). Potential substrates abundant 

in cotton (o-anisic acid, vanillic acid, syringic acid, ferulic acid and sinapic acid) that are structurally 

similar to dicamba, were not metabolized by an E. coli-produced N-terminal histidine DMO. In 

addition, E. coli-produced MON 88701 DMO did not metabolize o-anisic acid, the endogenous 

compound that has the greatest structural similarity to dicamba. These laboratory tests indicate that 

DMO, including MON 88701 DMO protein, is specific for dicamba. See Appendix I, section 

VI.A.3. Given the limited amount of chlorinated metabolites with structures similar to dicamba in 

plants and other eukaryotes (Wishart, 2010; Wishart et al., 2009), it is unlikely that MON 88701 

DMO will catalyze the conversion of other endogenous substrates. Therefore, the activity of the 

enzyme is specific for dicamba while it maintains many structural properties common to oxygenases 

that are ubiquitous to all organisms with a history of safe consumption.

H.2.2.2.1.4. bar Donor Organism Safety

S. hygroscopicus is a saprophytic, soil-borne bacterium with no known safety issues. Streptomyces species 

are widespread in the environment and present no known allergenic or toxicity issues (Kämpfer, 

2006; Kutzner, 1981) though human exposure is quite common (Goodfellow and Williams, 1983). S. 

hygroscopicus is not considered pathogenic to plants, humans or other animals (Cross, 1989; 

Goodfellow and Williams, 1983; Locci, 1989). The history of safe use of S. hygroscopicus is discussed 

previously (Hérouet et al., 2005), and this organism has been extensively reviewed during the 

deregulation of several glufosinate-tolerant events with no safety or allergenicity issues identified.

The ubiquitous presence of S. hygroscopicus in the environment, the widespread human exposure 

without any adverse safety or allergenicity reports, and the successive reviews resulting from the 

deregulation of several glufosinate-tolerant events with no safety or allergenicity issues identified 

establishes the safety of the donor organism.

H.2.2.2.1.5. PAT Protein has a History of Safe Use

The PAT (bar) protein expressed in DGT cotton is identical to the wild-type protein produced in S. 

hygroscopicus and is analogous to the PAT proteins in commercially available glufosinate-tolerant 

products in several crops including cotton, corn, soybean, and canola. Based on studies 

characterizing the kinetic and chemical mechanisms of PAT proteins (Wehrmann et al., 1996), 

OECD recognizes PAT proteins produced from different genes to be equivalent with regard to 

function and safety (OECD, 1999b).

The safety of PAT protein present in biotechnology-derived crops has been extensively assessed 

(ILSI-CERA, 2011) and in 1997 a tolerance exemption was issued for PAT proteins by U.S. EPA 

(U.S. EPA, 1997). This exemption was based on a safety assessment that included rapid digestion in 

simulated gastric fluids, lack of significant homology to known toxins and known allergens, and lack 

of toxicity in an acute oral mouse gavage study. Numerous glufosinate-tolerant products including 

those in corn, soy, canola, sugarbeet and rice have been reviewed by the USDA and FDA with no 

concerns identified. Further, a comprehensive study on the safety of PAT proteins present in 

biotechnology-derived crops (Hérouet et al., 2005) demonstrated structural similarity only with other 

acetyltransferases known to not cause adverse effects after consumption, lack of sequence homology 

to know allergens and toxins, lack of glycosylation sites, rapid degradation in gastric and intestinal 
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fluids, and no adverse effects in mice treated with high doses of PAT proteins. Hérouet et al. 

concluded that there is a reasonable certainty of no harm resulting from the inclusion of PAT 

proteins in human food or animal feed (2005).

The history of safe use of PAT is supported by the lack of any documented reports of adverse 

effects related to this protein since the introduction of glufosinate-tolerant crops in 1995 (Duke and 

Powles, 2009). Since then, approvals have been issued by regulatory agencies of 11 different 

countries for the environmental release of greater than 38 transformation events, including 8 

different species of plants expressing the PAT protein (ILSI-CERA, 2011).

H.2.2.2.1.6. PAT (bar) Catalyzes a Specific Enzyme Reaction

The mode-of-action for PAT protein has been extensively assessed, as numerous glufosinatetolerant products, including those in corn, soy, canola, sugarbeet, and rice, have been reviewed by 

the FDA and several other regulatory agencies (ILSI-CERA, 2011; OECD, 1999b; 2002). PAT, 

including the PAT (bar) protein produced in DGT cotton, is an enzyme classified as an 

acetyltransferase which acetylates glufosinate to produce non-herbicidal N-acetyl glufosinate. 

Glufosinate is a racemic mixture of the D- and L- forms of phosphinothricin. The herbicidal activity 

of glufosinate results from the binding of L-phosphinothricin to glutamine synthetase (OECD, 

1999b; 2002). Glutamine synthetase is responsible for the assimilation of ammonia generated during 

photorespiration. The binding of L-phosphinothricin to glutamine synthetase results in the 

inactivation of glutamine synthetase and a subsequent toxic build-up of ammonia within the plant, 

resulting in death of the plant (Manderscheid and Wild, 1986; OECD, 1999b; 2002; Wild and 

Manderscheid, 1984).

The PAT (bar) protein produced in DGT cotton acetylates the free amine group of 

Lphosphinothricin form of glufosinate to produce non-herbicidal N-acetyl glufosinate. The 

acetylated glufosinate is unable to bind to glutamine synthetase and therefore does not disrupt 

photorespiration and avoids the build-up of ammonia. Therefore, the production of PAT (bar) 

protein in DGT cotton confers glufosinate herbicide tolerance through this mechanism.

The PAT proteins, including PAT (bar), are highly specific for glufosinate in the presence of acetylCoA (Thompson et al., 1987; Wehrmann et al., 1996). While the herbicidal activity of glufosinate 

comes from the L-amino acid form, other L-amino acids are unable to be acetylated by PAT protein 

and competition assays containing glufosinate, high concentrations of other amino acids and PAT 

showed no inhibition of glufosinate acetylation (Wehrmann et al., 1996). Furthermore, L-glutamate, 

an analogue of glufosinate, also showed no inhibition of glufosinate acetylation in competition 

assays (Wehrmann et al., 1996). In addition, the PAT (bar) protein has more than 30-fold higher 

affinity towards L-phosphinothricin over other plant analogues (Thompson et al., 1987). Thus, the 

PAT (bar) protein has high substrate specificity for L-phosphinothricin, the herbicidal component of 

glufosinate, and is unlikely to affect the metabolic system of DGT cotton. Numerous glufosinatetolerant products, including those in corn, soy, canola, sugarbeet, and rice have been reviewed with 

no concerns identified (ILSI-CERA, 2011).

H.2.2.2.1.7. DGT Cotton Allergenicity

Assessing the potential allergenicity of the expressed proteins is less relevant to DGT cotton since 

only cottonseed oil and linters from cotton are used in food applications, which have undetectable 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 928 of 946

or negligible amounts of total protein (Reeves and Weihrauch, 1979; Sims et al., 1996). Nonetheless, 

the allergenic potential of MON 88701 DMO and PAT (bar) proteins was assessed by comparing the 

biochemical characteristics of these introduced proteins to biochemical characteristics of known 

allergens (Codex Alimentarius, 2009). A protein is not likely to be associated with allergenicity if: 1) 

the protein is from a non-allergenic source; 2) the protein represents a very small portion of the total 

plant protein; 3) the protein does not share structural similarities to known allergens based on the 

amino acid sequence; and 4) the protein is rapidly digested in mammalian gastrointestinal systems.

MON 88701 DMO has been assessed for its potential allergenicity according to the safety 

assessment guidelines described above (see Appendix I), and conclusions were as follows:

1) MON 88701 DMO originates from S. maltophilia, an organism that has not been reported 

to be a source of known allergens.

2) MON 88701 DMO represents no more than 0. 008% of the total protein in the 

cottonseed of DGT cotton.250 Therefore, the MON 88701 DMO protein represents a very 

small portion of the total protein in the cottonseed of DGT cotton and due to the harsh 

conditions used in cottonseed processing is most likely absent in the oil and linters that are 

used for food production.

3) Bioinformatics analyses demonstrated that the MON 88701 DMO does not share amino 

acid sequence similarities with known allergens and, therefore, is highly unlikely to contain 

immunologically cross-reactive allergenic epitopes.

4) In vitro digestive fate experiments conducted with the MON 88701 DMO demonstrate 

that the proteins are rapidly digested in simulated gastric fluid (SGF) and in simulated 

intestinal fluid (SIF).

Taken together, these data support the conclusion that MON 88701 DMO does not pose a 

significant allergenic risk. See Appendix I.

The non-allergenic nature of PAT (bar) protein is established in the scientific literature (Hérouet et 

al., 2005) and by the tolerance exemption set by U.S. EPA (1997). Furthermore, the safety of PAT 

proteins, including the PAT (bar) protein produced in DGT cotton, has been assessed extensively by 

regulatory agencies in 11 different countries for more than 38 biotechnology-derived events in eight 

different species (ILSI-CERA, 2011). In addition, potential allergenicity of PAT (bar) protein 

produced in DGT cotton has been assessed according to the safety assessment guidelines described 

above (see Appendix I), and conclusions were as follows.

1) PAT (bar) originates from S. hygroscopicus, an organism that has not been reported to be a 

source of known allergens.

 

250 % protein = (Mean level of protein expression (μg/g)/ Mean dry weight of total protein in seed μg/g) x 100 %
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 929 of 946

2) PAT (bar) represents no more than 0. 002% of the total protein in the cottonseed of DGT 

cotton.

251

 Therefore, the PAT (bar) protein represents a very small portion of the total 

protein in the cottonseed of DGT cotton and due to the harsh conditions used in 

cottonseed processing is most likely absent in the oil and linters that are used for food 

production.

3) Bioinformatics analyses demonstrated that the PAT (bar) does not share amino acid 

sequence similarities with known allergens and, therefore, is highly unlikely to contain 

immunologically cross-reactive allergenic epitopes.

4) In vitro digestive fate experiments conducted with the PAT (bar) demonstrate that the 

proteins are rapidly digested in simulated gastric fluid (SGF) and in simulated intestinal fluid 

(SIF).

Taken together, these data support the conclusion that PAT (bar) does not pose a significant 

allergenic risk.

H.2.2.2.1.8. MON 88701 DMO and PAT (bar) are Labile in in vitro Digestion Assays

MON 88701 DMO and PAT (bar) were readily digestible in simulated gastric fluid (SGF) and 

simulated intestinal fluid (SIF). Rapid degradation of the MON 88701 DMO and PAT (bar) proteins 

in SGF and SIF makes it highly unlikely that either protein would be absorbed in the small intestine 

and have any adverse effects on human or animal health. (Monsanto 2012).

H.2.2.2.1.9. MON 88701 DMO and PAT (bar) Toxicity

Acute oral toxicology studies were conducted with MON 88701 DMO and PAT (bar) proteins 

individually. Results indicate that neither MON 88701 DMO or PAT (bar) caused any adverse 

effects in mice, with No Observable Adverse Effect Levels (NOAELs) for MON 88701 DMO at 

283 mg/ kg bw and PAT (bar) at 1086 mg/kg bw, respectively, the highest doses tested. (Monsanto 

2012).

Cottonseed is not consumed by humans because the majority of commercial cotton varieties contain 

the anti-nutrients gossypol and cyclopropenoid fatty acids. The primary human food currently 

produced from cottonseed is refined, bleached, and deodorized (RBD) oil, and to a smaller extent, 

linters. RBD oil contains undetectable amounts of protein (Reeves and Weihrauch, 1979); therefore, 

oil produced from DGT cotton will contain extremely low levels of MON 88701 DMO and PAT 

(bar) proteins. Linters are an industrial by-product of ginning, and can be consumed as a highly 

processed product composed of nearly pure (i.e., >99%) cellulose (NCPA, 2002; Nida et al., 1996). 

Cottonseed RBD oil and linters are processed fractions that contain undetectable or negligible 

amounts of protein there is minimal, if any, dietary exposure to MON 88701 DMO and PAT (bar) 

proteins from consumption of foods derived from DGT cotton. Therefore, MOE values were not 

calculated for the MON 88701 DMO or PAT (bar) proteins. Furthermore, the safety of PAT (bar) 

 

251 % protein = (Mean level of protein expression (μg/g)/ Mean dry weight of total protein in seed μg/g) x 100 %
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 930 of 946

has been extensively assessed (Hérouet et al., 2005), several glufosinate-tolerant crops that produce 

PAT proteins have been reviewed by FDA and other regulatory agencies (ILSI-CERA, 2011) and in 

1997 a tolerance exemption was issued for PAT proteins by U.S. EPA (1997).

Estimated exposure of MON 88701 DMO and PAT (bar) proteins in animal feed were evaluated by 

calculating an estimate of daily dietary intake (DDI) for dairy cows. Exposure was calculated for the 

worst-case scenario, which assumes: 1) the source of cottonseed in the diet is cottonseed meal; 2) 

cottonseed meal is only derived from DGT cotton and contains no other cottonseed sources; 3) the

protein expression level is the maximum expression level measured for each protein; and 4) there 

would be no loss of protein due to heat. The maximum daily amount of MON 88701 DMO or PAT 

(bar) proteins consumed from DGT cotton would be for the dairy cow and would be 0.00043 g/kg 

of body weight for MON 88701 DMO and 0.000124 g/kg of body weight for PAT (bar). These 

values represent 0.007 and 0.002% of protein consumed, respectively. These very small levels of 

exposure of animals to MON 88701 DMO and PAT (bar) in their feed, in addition to the above 

mentioned safety data for both MON 88701 DMO and PAT (bar), support the conclusion that there 

is no risk to animal health when MON 88701 DMO or PAT (bar) are present in their diets.

H.2.2.2.1.10. DGT Cotton Safety Assessment Conclusions

In April of 2013 Monsanto concluded consultations with the FDA regarding the safety of DGT 

cotton in food and feed. After considering the above-described findings, along with comprehensive 

submissions of data and research, the FDA concluded that it had no further questions about food 

and feed derived from DGT cotton. Food and feed products containing DGT cotton or derived 

from DGT cotton are as safe as cotton currently on the market for human and animal consumption. 

See Appendix I.

H.2.2.2.2. Dicamba Reaction Product Safety Assessment

MON 88701 DMO rapidly demethylates dicamba rendering it inactive, thereby conferring tolerance 

to dicamba in DGT cotton. In dicamba-treated DGT cotton, the demethylation of dicamba 

produces 3,6-dichlorosalicylic acid (DCSA), a known cotton, soybean, soil, and livestock metabolite 

whose safety has been evaluated by the Environmental Protection Agency (U.S. EPA), and 

formaldehyde. In the absence of a dicamba treatment on DGT cotton, DCSA and formaldehyde 

would not be produced. DCSA is structurally similar to salicylic acid (SA). Numerous studies have 

reported on the stress defense activities of SA, although most studies have looked at the protective 

effects of exogenously applied SA (Janda et al, 2007). Formaldehyde has a potential linkage to 

apoptosis in plants (Szende and Tyihak, 2010), and formaldehyde concentrations in plants have been 

found to increase under certain stress conditions (Szabo et al, 2003). The National Toxicology 

Program (NTP) 12th Report on Carcinogens has reclassified formaldehyde as a known human 

carcinogen (USHHS-NTP, 2011). The relevant route of exposure for this health risk is from 

repeated inhalation at levels associated with indoor or occupational environments, which are 

generally higher than outdoor environments (USHHS-NTP, 2011). Formaldehyde is present in food 

and in the human body naturally, and there is no evidence to suggest that dietary intake of 

formaldehyde is important (USHHS-NTP, 2011). 

A full discussion on DCSA, and the safety of this metabolite, is provided in Appendix L of the 

Monsanto Petition for Determination of Nonregulated Status for DT Soybean (Monsanto 2010). 

DCSA residue levels were measured in dicamba-treated DGT cotton to support Monsanto’s 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 931 of 946

registration request for the inclusion of DCSA in the cottonseed and gin byproduct dicamba residue 

definitions. DCSA is structurally similar to salicylic acid (SA). Numerous studies have reported on 

the stress defense activities of SA, although most studies have looked at the protective effects of 

exogenously applied SA (Janda et al, 2007).

Formaldehyde is ubiquitous in the environment and present in plants and animals. Formaldehyde 

was not considered a relevant metabolite in the demethylation of dicamba by the EPA. According 

to the guidelines published by Office of Prevention, Pesticides and Toxic Substances, United States 

Environmental Protection Agency (US EPA OPPTS 860.1300), the methoxy sidechain that is 

cleaved from dicamba to form formaldehyde would specifically not be chosen to be labeled in a 

metabolism study (U.S. EPA, 1996). This is because it is not metabolically stable and would not be 

considered a significant moiety, as it would be readily metabolized and incorporated into the 1-

carbon pool of the plant through known pathways. Therefore, formaldehyde was not measured in 

the residue study when dicamba was applied to DGT cotton.

Data from both dicamba and glufosinate-treated and not treated DGT cotton compared to a 

conventional control are available from multiple sites across the U.S., where agronomic, phenotypic 

and environmental interaction data were collected. The results of this assessment demonstrate no 

biologically meaningful difference between DGT cotton treated with and without dicamba and 

glufosinate and the conventional control, and support a conclusion that the formation of DCSA and 

formaldehyde does not alter the weedy characteristics or increase susceptibility or tolerance to 

diseases, insect pests or abiotic stresses. Therefore, DGT cotton, as cultivated, is no more likely to 

be a plant pest risk or have a biologically meaningful change in environmental impact than 

conventional cotton.

Further, the metabolism of formaldehyde in plants is well understood, and there are a number of 

natural occurring sources of formaldehyde in plants. For example, it is produced during the process 

of photorespiration (Oliver, 1994) and during oxidative demethylation of DNA (Zhu, 2009), which 

supports why formaldehyde is not considered a byproduct of interest as dicamba is demethylated. It 

is well known and understood that formaldehyde is rapidly metabolized in plants through two basic 

routes: 1) it can be incorporated into the one-carbon folate pool via spontaneous or enzymemediated formation of methylene tetrahydrofolate (Hanson and Roje, 2001); or 2) it can be oxidized 

to formate by a detoxification pathway that begins with spontaneous formation of the glutathione 

adduct S-hydroxymethylglutathione (Hanson and Roje, 2001). In each case, formaldehyde is further 

metabolized to carbon dioxide or entered into the 1C folate pool (Hanson and Roje, 2001; Giese et 

al., 1994). 

The maximum theoretical production of formaldehyde produced from dicamba-treated DGT cotton 

is estimated to be 6.3 mg/kg and 33 mg/kg.252 This is well within the range of formaldehyde 

 

252 Calculation based an assumption that the entire 0.56 kg/ha (0.5 lb/acre a.e.) application of dicamba that is intercepted by the DGT

cotton plant at the 6-leaf or first bloom plus 15 day growth stage is instantaneously and completely absorbed, and then 

instantaneously metabolized by the DMO enzyme (Complete demethylation of 560 g (2.5 mol)/ ha dicamba would yield 2.5 

mol/ha formaldehyde). Canopy closure, and thus spray interception, is estimated at 30% at the 6-leaf stage (Krutz et al., 2012), 

resulting in production of 23 g/ha formaldehyde. Canopy closure is near complete at the first bloom plus 15 day growth stage 

(Reddy et al., 2009), so no adjustment is applied. Above-ground biomass of 6-leaf plants is estimated to be 0.7 metric tons/ha 

(Ducamp et al., 2012), and the estimated maximum theoretical concentration is 33 mg/kg formaldehyde in plants. For dicamba 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 932 of 946

concentrations measured for a variety of agricultural commodities, including up to 60 mg/kg in 

fruits and vegetables (WHO-IPCS, 1989). Plants have a large capacity to metabolize formaldehyde 

naturally produced from internal processes (A. Hanson (2011), C.V. Griffin, Sr. Eminent Scholar, 

Horticulture Department, University of Florida, Personal Communication), and any additional 

amount of formaldehyde that could be theoretically produced in the plant by dicamba treatment in 

DGT cotton would be metabolized very quickly. Thus the incremental increase in formaldehyde 

over and above the levels already presumed to be present in the cotton plant would be small and 

transient and associated with an outdoor application of dicamba herbicide. Further, since current 

literature supports that formaldehyde is only emitted from foliage under certain conditions 

(Nemecek-Marshall et al., 1995; Cojocariu et al., 2004; Cojocariu et al., 2005) and that emission rates 

are low (Nemecek-Marshall et al., 1995), little opportunity exists for formaldehyde to be released 

from DGT cotton after dicamba treatment. Therefore human safety concerns of formaldehyde 

released from dicamba-treated DGT cotton are considered to be negligible and the most relevant 

route of exposure is from repeated inhalation of concentrated levels associated with indoor or 

occupational environments. USHHS-NTP (2011) has already stated that there is no evidence to 

suggest that dietary intake of formaldehyde is important, despite NTP’s 12th Report on Carcinogens 

reclassifying formaldehyde as a known human carcinogen by (USHHS-NTP, 2011). In addition, the 

only human food currently produced from cottonseed is refined, bleached, and deodorized (RBD) 

oil, and to a smaller extent, linters. Therefore, the potential for human exposure to any 

formaldehyde in dicamba-treated DGT cotton cottonseed is highly unlikely.

In addition to formaldehyde production in plants, plants and animals are constantly exposed to low 

levels of formaldehyde. Formaldehyde is already present in the environment and the atmosphere 

from a variety of biogenic (e.g. plant and animal) and anthropogenic (e.g. automotive or industrial 

emissions) sources. Additionally, formaldehyde degrades rapidly in environmental compartments 

(air, soil, and water). In water, formaldehyde dissipates through biodegradation to low levels in a 

few days (USHHS-ATSDR, 1999). Aerobic biodegradation half-lives are estimated to be 1-7 days 

for surface water and 2-14 days for ground water (US EPA, 2008). The half-life of formaldehyde in 

air is dependent on a number of factors (light intensity, temperature and location). Through 

reaction with hydroxyl radical, the half-life of formaldehyde in air varies from 7 to 70 hours (US 

EPA, 2008). The photolytic half-life of formaldehyde in air (e.g., in the presence of sunlight) is 

estimated to be 1.6-6 hours (US EPA, 2008; USHHS-ATSDR, 1999). The rapid degradation of 

formaldehyde in the environment, combined with the understanding that formaldehyde is widely 

used by living organisms as a 1C source, support a conclusion that any environmental effects of 

formaldehyde, including effects on other plants and NTO’s, resulting from dicamba-treated DGT 

cotton would be negligible. 

Humans are also constantly exposed to low levels of formaldehyde. Human exposure to 

formaldehyde is primarily due to indoor and occupational air exposures (USHHS-ATSDR, 1999). 

Formaldehyde is also found in a variety of consumer products such as cosmetics and paints, often as 

an antimicrobial agent, and is used extensively in urea-formaldehyde “slow-release” fertilizer 

formulations and adhesives (USHHS-ATSDR, 1999). Indoor formaldehyde air concentrations are 

 

applications at first bloom plus 15 day growth stage, the crop biomass is estimated to be 12 metric tons/ha (Boquet and 

Breitenbeck, 2000), and the estimated maximum theoretical formaldehyde concentration produced in planta is 6.3 mg/kg.
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 933 of 946

generally significantly higher than outdoor air concentrations (USHHS-ATSDR, 1999) as a result of 

combustion (cooking, heating, tobacco use) and the emission of formaldehyde from a variety of 

construction materials (e.g., particle board, plywood or foam insulation) as well as permanent press 

fabrics (clothing or draperies) (US CPSC, 1997). Formaldehyde present in outdoor air results from a 

number of sources, and levels of formaldehyde are generally higher in urban areas than in rural areas 

(WHO-IPCS, 1989). Direct contributions of formaldehyde to the atmosphere (i.e., those in the 

form of formaldehyde itself) from man-made sources are present, but are generally considered to be 

small relative to natural sources or indirect production of formaldehyde in the atmosphere (WHO, 

2002). Formaldehyde is rapidly consumed in the atmosphere through direct photolysis or by 

oxidation with hydroxyl or nitrate radicals (USHHS-ATSDR, 1999).

The National Toxicology Program (NTP) 12th Report on Carcinogens has reclassified formaldehyde 

as a known human carcinogen (USHHS-NTP, 2011). However, the relevant route of exposure for 

this health risk is from repeated inhalation of concentrated levels associated with indoor or 

occupational environments. As previously discussed, formaldehyde may only be released by plants 

in very small quantities and under certain conditions. Any incremental exposure to formaldehyde 

associated with the application of dicamba to MON 88701 would occur outdoors, would be 

minimal, and also would be transient in nature. Therefore human safety concerns of formaldehyde 

released from dicamba treated DGT cotton are considered to be negligible. USHHS-NTP (2011) 

has already stated that there is no evidence to suggest that dietary intake of formaldehyde is 

important. In addition, cotton seed is not directly consumed by humans, and would be processed 

into food products, limiting potential exposure to humans to any formaldehyde in dicamba-treated 

DGT cotton seed.

H.2.2.3. Summary of Findings

Because direct human dietary exposure to cotton is generally limited to processed products that 

contain undetectable or negligible amounts of protein, there is minimal, if any, dietary exposure to 

MON 88701 DMO and PAT (bar) proteins from consumption of foods derived from DGT cotton. 

Although livestock are likely to be ingest these proteins or their byproducts, substantial analyses of 

the safety of these compounds has revealed that there is no reason to suspect that DGT cotton is 

any less safe than conventional cotton as an ingredient in food and feed. The presence of DGT 

cotton in food and feed presents negligible risks.

H.2.3. Dicamba-and-Glufosinate-Tolerant Cotton Presence in Food or Animal Feed

In efforts to assess the human health, livestock, and wildlife risks of exposure to DGT cotton, 

potential impacts from MON 88701 DMO, dicamba reaction byproducts, and PAT (bar) are 

evaluated in this report.

H.2.3.1. Probability of Presence

As discussed above, the inserted DNA in DGT cotton causes the production of MON 88701 DMO 

and PAT (bar) within the plant. In the expression level studies conducted by Monsanto, 

MON 88701 DMO and PAT (bar) were found in some amount in all tissue types. See Part 2.2.1.2. 

When exposed to dicamba, the MON 88701 DMO catalyzes the demethylation of dicamba to the 

non-herbicidal compound DCSA and formaldehyde. As a result, the probability of presence of these 

proteins and reaction byproducts in unprocessed cotton seed products is high. However, humans 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 934 of 946

generally do not consume unprocessed cotton sed. Human dietary exposure to cotton is generally 

limited to processed products that contain undetectable or negligible amounts of protein. Thus, the 

likelihood of direct human dietary exposure to these proteins is negligible. 

H.2.3.2. Health Effects of MON 88701 DMO, Dicamba Reaction Products, and PAT (bar)

H.2.3.2.1. Health Effects of MON 88701 DMO, Dicamba Reaction Products, and PAT (bar) 

on Humans

As discussed above, the MON 88701 DMO, dicamba reaction products, and PAT (bar) have been 

assessed for safety for human consumption. See Part 2.2.2. These assessments examined the donor 

organism safety, the similarity of MON 88701 DMO to a common class of mono-oxygenases, the 

dicamba-specificity of MON 88701 DMO, the specificity of PAT (bar), the history of safe use of the 

PAT protein, potential allergenicity issues, the digestibility of MON 88701 DMO and PAT (bar), and 

the toxicity of MON 88701 DMO, PAT (bar), and the dicamba reaction byproducts.253 These 

assessments concluded that the food and feed products containing DGT cotton or derived from 

DGT cotton are as safe as cotton currently on the market for human consumption. Additonally, 

Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DGT cotton, and FDA concluded that it had 

no additional questions.

Studies on the persistence of plant-derived native DNA and recombinant DNA in livestock have 

indicated that feed-ingested DNA fragments do survive in the terminal gastrointestinal (GI) tract 

and that uptake into the gut epithelium does occur (Sharma, 2006). However, recombinant DNA 

fragments were not found in visceral tissues, like the kidney. There is no evidence thus far to 

indicate that the recombinant DNA that encodes the inserted gene would be processed in a manner 

any differently from the endogenous feed-ingested genetic material. The risks associated with 

transgene fragment presence in feed and food is considered to be negligible.

H.2.3.2.2. Health Effects of MON 88701 DMO, Dicamba Reaction Products, and PAT (bar) 

on Livestock

Monsanto has completed the biotechnology consultation process with FDA for the safety and 

nutritional assessment of food and feed derived from DGT cotton. This consultation did not 

identify any biologically meaningful differences between the composition of DGT cotton and 

conventional cotton. As discussed above, MON 88701 DMO belongs to a common class of monooxygenases, regularly consumed by humans and animals, and PAT (bar) has a history of safe 

consumption. At the conclusion of the FDA consultation, FDA had no questions about the safety 

of DGT cotton for use in food or feed. 

H.2.3.2.3. Health Effects of MON 88701 DMO, Dicamba Reaction Products, and PAT (bar) 

on Non-Livestock Animals (Wildlife)

 

253 Monsanto has submitted a request for the inclusion of DCSA in the cottonseed and gin byproduct dicamba residue 

definitions. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 935 of 946

No specific data or scientific literature were found relating to the health effects of MON 88701 

DMO or PAT (bar) on non-livestock animals. As discussed above, MON 88701 DMO belongs to a 

common class of mono-oxygenases, regularly consumed by humans and animals, and PAT (bar) has 

a history of safe consumption. Additionally the results of acute oral toxicology studies for 

MON 88701 DMO and PAT (bar) indicated that neither MON 88701 DMO or PAT (bar) caused 

any adverse effects in mice, with No Observable Adverse Effect Levels (NOAELs) for MON 88701 

DMO at 283 mg/ kg bw and PAT (bar) at 1086 mg/kg bw, respectively, the highest doses tested. 

There is no evidence that MON 88701 DMO, PAT (bar), or dicamba reaction products will exhibit 

adverse biological activity toward wildlife. Because use of DGT cotton is compatible with 

conservation tillage practices, usage of DGT cotton may have a positive impact on wildlife. 

Conservation tillage practices can have a positive impact on wildlife, including beneficial arthropods 

(Altieri, 1999; Landis et al., 2005; Towery and Werblow, 2010). Conservation tillage practices 

benefit biodiversity due to decreased soil erosion leading to improved surface water quality, 

retention of vegetative cover, crop residues serving as a food source, and increased populations of 

invertebrates which can serve as food sources to other organisms (Landis et al. 2005; Sharpe, 2010).

H.2.3.3. Summary of Findings

There is little evidence that MON 88701 DMO, dicamba byproducts, or PAT (bar) have any direct 

toxic effect on livestock or any deleterious outcome on nutritional parameters. The information 

evaluated suggests that the presence of DGT cotton in human food and animal feed poses negligible

risks to humans, livestock, and wildlife. 
Monsanto Company 10-SY-210U / 12-CT-244U-S Page 936 of 946

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