Bayer CropScience Petition (08-340-01p) FOR 

Determination of Nonregulated Status of Insect 

Resistant and Glufosinate Ammonium-Tolerant 

(TwinLinkTM) Cotton, Gossypium hirsutum, Events 

T304-40 x GHB119 

OECD Unique Identifier: 

BCS-GH004-7 x BCS-GH005-8

Draft Environmental Assessment 

April 2011 

Agency Contact

Ms. Cynthia Eck, Document Control Officer USDA, APHIS, BRS 

4700 River Road, Unit 147 

Riverdale, MD 20737-1237 

Phone: (301) 734-0667 

Fax: (301) 734-8669 

Cynthia.A.Eck@aphis.usda.gov

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of 

race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. 

(Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for 

communication of program information (Braille, large print, audiotape, etc.) should contact USDA’S TARGET Center 

at (202) 720–2600 (voice and TDD). 

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326–W, Whitten Building, 

1400 Independence Avenue, SW, Washington, DC 20250–9410 or call (202) 720–5964 (voice and TDD). USDA is an 

equal opportunity provider and employer. 

Mention of companies or commercial products in this report does not imply recommendation or endorsement by the 

U.S. Department of Agriculture over others not mentioned. USDA neither guarantees nor warrants the standard of any 

product mentioned. Product names are mentioned solely to report factually on available data and to provide specific 

information. 

This publication reports research involving pesticides. All uses of pesticides must be registered by appropriate State 

and/or Federal agencies before they can be recommended. 
BAYER TWINLINKTM COTTON

TABLE OF CONTENTS PAGE

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ACRONYMS................................................................................................................................ iv

1 PURPOSE AND NEED..........................................................................................................1

1.1 REGULATORY AUTHORITY ................................................................................................... 1

1.2 REGULATED ORGANISMS ...................................................................................................... 2

1.3 PETITION FOR DETERMINATION OF NONREGULATED STATUS: BAYER 

CROPSCIENCE LEPIDOPTERAN-RESISTANT AND GLUFOSINATE AMMONIUMTOLERANT (TWINLINKTM) COTTON, EVENTS GHB119 AND T304-40 ........................... 2

1.4 PURPOSE OF PRODUCT ........................................................................................................... 3

1.5 APHIS RESPONSE TO PETITION FOR NONREGULATED STATUS ................................. 5

1.6 COORDINATED FRAMEWORK REVIEW .............................................................................. 6

1.7 PUBLIC INVOLVEMENT .......................................................................................................... 7

1.8 ISSUES CONSIDERED............................................................................................................... 7

2 AFFECTED ENVIRONMENT.............................................................................................9

2.1 COTTON USE AND BIOLOGY ................................................................................................. 9

2.1.1 Cotton Taxonomy ................................................................................................................. 9

2.1.2 Cotton Use .......................................................................................................................... 10

2.2 AGRICULTURAL PRODUCTION OF COTTON.................................................................... 10

2.2.1 Acreage and Areas of Cotton Production............................................................................ 10

2.2.2 Cropping Practices: Crop Rotation and Pesticide Use....................................................... 11

2.2.3 Seed Production .................................................................................................................. 13

2.2.4 Organic Farming ................................................................................................................. 14

2.2.5 Specialty Cotton Production ............................................................................................... 15

2.3 PHYSICAL ENVIRONMENT................................................................................................... 16

2.3.1 Water Resources ................................................................................................................. 16

2.3.2 Soil...................................................................................................................................... 17

2.3.3 Air Quality .......................................................................................................................... 18

2.3.4 Climate Change................................................................................................................... 19

2.4 ANIMAL AND PLANT COMMUNITIES................................................................................ 21

2.4.1 Animals............................................................................................................................... 21

2.4.2 Plants................................................................................................................................... 22

2.4.3 Biological Diversity ............................................................................................................ 24

2.4.4 Gene Movement.................................................................................................................. 25

2.5 PUBLIC HEALTH ..................................................................................................................... 27

2.6 ANIMAL FEED.......................................................................................................................... 29

2.7 SOCIOECONOMIC ISSUES..................................................................................................... 32

3 ALTERNATIVES.................................................................................................................34

3.1 NO ACTION: CONTINUATION AS A REGULATED ARTICLE......................................... 34
BAYER TWINLINKTM COTTON

TABLE OF CONTENTS, CONTINUED PAGE

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3.2 PREFERRED ALTERNATIVE: DETERMINATION THAT TWINLINKTM COTTON IS NO 

LONGER A REGULATED ARTICLE ..................................................................................... 34

3.3 ALTERNATIVES CONSIDERED BUT REJECTED FROM FURTHER CONSIDERATION35

3.3.1 Prohibit Any TwinLinkTM Cotton from Being Released .................................................... 35

3.3.2 Approve the petition in part.............................................................................................. 35

3.3.3 Isolation distance between TwinLinkTM Cotton and non-GE cotton and geographical 

restrictions.......................................................................................................................... 36

3.3.4 Requirement of Testing For TwinLinkTM Cotton ............................................................... 36

3.4 COMPARISON OF ALTERNATIVES ..................................................................................... 37

4 ENVIRONMENTAL CONSEQUENCES..........................................................................39

4.1 SCOPE OF THE ENVIRONMENTAL ANALYSIS................................................................. 39

4.2 AGRICULTURAL PRODUCTION OF COTTON.................................................................... 40

4.2.1 Acreage and Areas of Cotton Production............................................................................ 40

4.2.2 Cropping Practices: Crop Rotation and Pesticide Use....................................................... 41

4.2.3 Seed Production .................................................................................................................. 44

4.2.4 Organic Farming ................................................................................................................. 44

4.2.5 Specialty Cotton Production ............................................................................................... 46

4.3 PHYSICAL ENVIRONMENT................................................................................................... 47

4.3.1 Water Resources ................................................................................................................. 47

4.3.2 Soil...................................................................................................................................... 48

4.3.3 Air Quality .......................................................................................................................... 50

4.3.4 Climate Change................................................................................................................... 51

4.4 ANIMAL AND PLANT COMMUNITIES................................................................................ 52

4.4.1 Animals............................................................................................................................... 52

4.4.2 Plants................................................................................................................................... 55

4.4.3 Biological Diversity ............................................................................................................ 56

4.4.4 Gene Movement.................................................................................................................. 58

4.5 PUBLIC HEATH........................................................................................................................ 62

4.5.1 Human Health ..................................................................................................................... 62

4.5.2 Worker Safety ..................................................................................................................... 65

4.6 ANIMAL FEED.......................................................................................................................... 66

4.7 SOCIOECONOMIC ISSUES..................................................................................................... 68

4.7.1 Domestic Economic Environment at Risk .......................................................................... 68

4.7.2 Trade Economic Environment at Risk ................................................................................ 69

4.7.3 Social Environment at Risk................................................................................................. 71

4.8 OTHER CUMULATIVE EFFECTS .......................................................................................... 73

4.9 THREATENED AND ENDANGERED SPECIES.................................................................... 73

4.9.1 Potential Effects of TwinLinkTM Cotton and Agricultural Practices on TES ..................... 75
BAYER TWINLINKTM COTTON

TABLE OF CONTENTS, CONTINUED PAGE

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4.9.2 Potential Effects of the Use of Glufosinate Ammonium..................................................... 79

4.10 CONSIDERATION OF EXECUTIVE ORDERS, STANDARDS, AND TREATIES 

RELATING TO ENVIRONMENTAL IMPACTS.................................................................... 80

4.10.1 Executive Orders with Domestic Implications ................................................................... 80

4.10.2 International Implications................................................................................................... 83

4.10.3 Compliance with Clean Water Act and Clean Air Act ....................................................... 84

4.10.4 Impacts on Unique Characteristics of Geographic Areas................................................... 84

4.10.5 National Historic Preservation Act (NHPA) of 1966 as Amended..................................... 85

5 BIBLIOGRAPHY.................................................................................................................86

6 LIST OF PREPARERS........................................................................................................99

APPENDICES

Appendix A APHIS Threatened and Endangered Species Decision Tree for FWS

Consultations

Appendix B Threatened and Endangered Species

LIST OF TABLES PAGE

Table 2-1: Cotton Fiber: World Production in Select Countries, 2006 to 2010/11 (estimated) 

(1,000 metric tons).................................................................................................10

Table 2-2: Cotton Pests Ranked in Order of Bales Lost, Presenting Percent U.S. Cotton Yield 

Reduction, Number of Cotton Acres Infested, Percent of U.S. Cotton Infested, 

Bales Lost, in 2009 ................................................................................................12

Table 3-1: Summary of Potential Impacts and Consequences of Alternatives.......................38

Table 4-1: Summary of Insecticide Use for Lepidopteran Control in Cotton Compared with 

Adoption of Bt Cotton ...........................................................................................43
BAYER TWINLINKTM COTTON

ACRONYMS

iv

AIA advanced informed agreement

AMS Agricultural Marketing Service

ANZFA Australia and New Zealand Food Authority

AOSCA Association of Official Seed Certifying Agencies

APHIS Animal and Plant Health Inspection Service

ARMS Agricultural Resource Management Survey

BCS Bayer Crop Science

BRAD Biopesticides Registration Action Document

BRS Biotechnology Regulatory Service

BXN bromoxynil-tolerant

CBD Convention on Biological Diversity

CBW cotton bollworm

CEQ Council of Environmental Quality

CFIA Canadian Food Inspection Agency

CFR Code of Federal Regulations

DNA deoxyribonucleic acid

EA Environmental Assessment

ECOS Environmental Conservation Online System

ELS extra-long staple

EO Executive Order

EPA Environmental Protection Agency

ERA ecological risk assessment

ESA Endangered Species Act

EU European Union

FAW fall armyworm

FDA Food and Drug Administration

FFDCA Federal Food, Drug, and Cosmetic Act

FFP food, feed, or processing

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FR Federal Register

GE genetically engineered

GHG greenhouse gases

IPCC Intergovernmental Panel on Climate Change

LMO living modified organism

MFA Multifibre Arrangement

MOU memorandum of understanding

N2

NABI North American Biotechnology Initiative

O nitrous oxide

NAPPO North American Plant Protection Organization

NEPA National Environmental Policy Act

NHPA National Historic Preservation Act

NMFS National Marine Fisheries Service

NOP National Organic Program

NRCS National Resources Conservation Service
BAYER TWINLINKTM COTTON

ACRONYMS, CONTINUED

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OECD Organization for Economic Cooperation and Development

OSTP Office of Science and Technology Policy

PAT phosphinothricin-acetyl-transferase

PBO Plant Biosafety Office

PGF pollen-mediated gene flow

PPA Plant Protection Act

RR Roundup Ready (registered trademark)

RSPM Regional Standards for Phytosanitary Measures

TBW tobacco budworm

TES threatened and endangered species

TSCA Toxic Substances Control Act

U.S.C. United States Code

USDA U.S. Department of Agriculture

USFWS U.S. Fish and Wildlife Service

WPS worker protection standard
BAYER TWINLINKTM COTTON

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1 PURPOSE AND NEED

1.1 REGULATORY AUTHORITY

“Protecting American agriculture” is the basic charge of the U.S. Department of Agriculture's 

(USDA) Animal and Plant Health Inspection Service (APHIS). APHIS provides leadership in 

ensuring the health and care of plants and animals. The agency improves agricultural 

productivity and competitiveness, and contributes to the national economy and the public health. 

USDA asserts that all methods of agricultural production (conventional, organic, or the use of 

genetically engineered varieties) can provide benefits to the environment, consumers, and farm 

income. 

Since 1986, the United States government has regulated genetically engineered (GE) organisms 

pursuant to a regulatory framework known as the Coordinated Framework for the Regulation of 

Biotechnology (Coordinated Framework) (51 FR 23302, 57 FR 22984). The Coordinated 

Framework, published by the Office of Science and Technology Policy, describes the 

comprehensive federal regulatory policy for ensuring the safety of biotechnology research and 

products and explains how federal agencies will use existing Federal statutes in a manner to 

ensure public health and environmental safety while maintaining regulatory flexibility to avoid 

impeding the growth of the biotechnology industry. The Coordinated Framework is based on 

several important guiding principles: (1) agencies should define those transgenic organisms 

subject to review to the extent permitted by their respective statutory authorities; (2) agencies are 

required to focus on the characteristics and risks of the biotechnology product, not the process by 

which it is created; (3) agencies are mandated to exercise oversight of GE organisms only when 

there is evidence of “unreasonable” risk. 

The Coordinated Framework explains the regulatory roles and authorities for the three major 

agencies involved in regulating GE organisms: USDA’s Animal and Plant Health Inspection 

Service (APHIS), the Food and Drug Administration (FDA), and the Environmental Protection 

Agency (EPA). 

APHIS is responsible for regulating GE organisms and plants under the plant pest authorities in 

the Plant Protection Act of 2000, as amended (7 USC § 7701 et seq.) to ensure that they do not 

pose a plant pest risk to the environment.

The FDA regulates GE organisms under the authority of the Federal Food, Drug, and Cosmetic 

Act (FFDCA). The FDA is responsible for ensuring the safety and proper labeling of all plantderived foods and feeds, including those that are genetically engineered. To help developers of 

food and feed derived from GE crops comply with their obligations under Federal food safety 

laws, FDA encourages them to participate in a voluntary consultation process. All food and feed 

derived from GE crops currently on the market in the United States have successfully completed 

this consultation process. The FDA policy statement concerning regulation of products derived 

from new plant varieties, including those genetically engineered, was published in the Federal 

Register on May 29, 1992 (57 FR 22984-23005). Under this policy, FDA uses what is termed a 

consultation process to ensure that human food and animal feed safety issues or other regulatory 

issues (e.g., labeling) are resolved prior to commercial distribution of bioengineered food.
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The EPA regulates plant-incorporated protectants under the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA) and certain biological control organisms under the Toxic Substances 

Control Act (TSCA). The EPA is responsible for regulating the sale, distribution and use of 

pesticides, including pesticides that are produced by an organism through techniques of modern 

biotechnology.

1.2 REGULATED ORGANISMS

The APHIS Biotechnology Regulatory Service’s (BRS) mission is to protect America’s 

agriculture and environment using a dynamic and science-based regulatory framework that 

allows for the safe development and use of GE organisms. APHIS regulations at 7 Code of 

Federal Regulations (CFR) Part 340 (hereafter Part 340), which were promulgated pursuant to 

authority granted by the PPA, regulate the introduction (importation, interstate movement, or 

release into the environment) of certain GE organisms and products. A GE organism is no 

longer subject to the plant pest provisions of the Plant Protection Act or to the regulatory 

requirements of Part 340 when APHIS determines that it is unlikely to pose a plant pest risk. A 

GE organism is considered a regulated article under Part 340 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 is also considered a plant pest. A GE organism is also 

regulated under Part 340 when APHIS has reason to believe that the GE organism may be a plant 

pest or APHIS does not have information to determine if the GE organism is unlikely to pose a 

plant pest risk. 

A person may petition the agency that a particular regulated article is unlikely to pose a plant 

pest risk, and therefore, is no longer regulated under the plant pest provisions of the Plant 

Protection Act or the regulations at 7 CFR 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 Plant Protection Act when APHIS determines that it is unlikely to pose a 

plant pest risk.

1.3 PETITION FOR DETERMINATION OF NONREGULATED STATUS: BAYER 

CROPSCIENCE LEPIDOPTERAN-RESISTANT AND GLUFOSINATE

AMMONIUM-TOLERANT (TWINLINKTM) COTTON, EVENTS GHB119 AND 

T304-40

Bayer Crop Science (BCS) has submitted a petition (APHIS Number 08-340-01p) seeking a 

determination that TwinLinkTM Cotton Events GHB119 and T304-40 are unlikely to pose a plant 

pest risk and, therefore, should no longer be a regulated article under regulations at 7 CFR Part

340. 

TwinLinkTM Cotton is a combined-trait cotton developed using conventional breeding techniques 

to link two deoxyribonucleic acid (DNA) transformation events; each developed using DNA 

recombinant techniques. By crossing BCS’ Cry1Ab Cotton (event T304-40) with BCS’ Cry2Ae 

Cotton (event GHB119), BCS has developed a cotton resistant to lepidopteran pests. The 
BAYER TWINLINKTM COTTON

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TwinLinkTM Cotton also expresses a glufosinate ammonium herbicide tolerance trait based on 

LibertyLink®

TwinLinkTM Cotton is currently regulated under 7 CFR Part 340. Interstate movement, 

importation, and field testing of TwinLinkTM Cotton have been conducted under notifications 

acknowledged by APHIS. 

technology. 

1.4 PURPOSE OF PRODUCT

BCS has developed the TwinLinkTM Cotton as an alternative insect-resistant and herbicidetolerant cotton product. 

BCS has developed upland or Mexican cotton (Gossypium hirsutum) plants that express two 

insecticidal crystalline proteins, Cry1Ab and Cry2Ae, derived from the common soil bacterium, 

Bacillus thuringiensis (Bt). The Cry1Ab and Cry2Ae proteins in TwinLinkTM Cotton are 

effective in controlling lepidopteran larvae such as bollworm (CBW, Helicoverpa zea), tobacco 

budworm (TBW, Heliothis virenscens), and fall armyworm (FAW, Spodoptera frugiperda) 

which are common pests of cotton. The rationale for using two Bt genes is that target insects are 

much less likely to develop resistance to both proteins simultaneously than to develop resistance 

to one toxic protein. In addition to the Cry1Ab and Cry2Ae proteins, the TwinLinkTM Cotton

contains the modifying phosphinothricin-acetyl-transferase (PAT) enzyme, encoded by the bar 

gene which confers tolerance to glufosinate ammonium-based herbicides. The bar gene, derived 

from Streptomyces hygroscopicus, encodes the PAT enzyme which acts to convert glufosinate

ammonium into its inactive form, thus rendering the plant tolerant to the herbicide. This is the 

same enzyme that is expressed in BCS LibertyLink®

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 (

Cotton (LLCotton25) that also confers 

tolerance to glufosinate ammonium herbicides.

US-EPA, 2009). In 2010, the 

USDA estimates that 18.9 million bales were harvested (USDA-NASS, 2010a) with 

approximately 10.9 million acres planted (USDA-NASS, 2010b). Cotton growers strive for high 

yields of high-value cotton fiber at the lowest production cost. To enhance successful cotton 

fiber production, the cotton industry relies heavily on pest control measures to control both 

weeds and lepidopteran insects. Infestation of cotton by lepidopteran larvae represents the 

largest insect threat to cotton production in the U.S. (Scott, 2008). To combat these threats and 

enhance production, cotton growers in the U.S. have adopted genetically improved cotton, to 

reduce pest management costs, obtain greater yields, and decrease pesticide costs; thereby 

producing greater grower return on investment (Scott, 2008). In 2010, 78% of all cotton grown 

in the U.S. contained herbicide-tolerant traits and 73% expressed insect-resistant traits (USDAERS, 2010a).

Cotton producers are currently limited to insect-resistant cotton varieties containing three 

Bacillus thuringiensis Cry1 endotoxin protein-based plant incorporated protectants. Each is 

deregulated by the USDA and registered by the EPA under FIFRA. The three proteins are 

Cry1Ac (Bollgard)—a combination of CrylAc and Cry2Ab2 (Bollgard II), Cry1F, and Cry1Ac 

(Widestrike) (USDA-APHIS, 2010a). These transgenic varieties offer almost complete 

protection against tobacco budworm, but may require additional applications of insecticide for 
BAYER TWINLINKTM COTTON

4

control of cotton bollworm. Hence, despite the wide adoption of these Bt cotton varieties to 

control lepidopteran insects, these same species continue to be the most economically important 

pests of the crop. In 2009, it was estimated that the Heliothine complex of tobacco budworm and 

cotton bollworm infested 4.3 million acres of cotton and reduced yields across the Cotton Belt by 

91,119 bales (Williams, 2010). Total 2009 cost and loss estimates for arthropod cotton pests 

were $502 million dollars (Williams, 2010). 

TwinLinkTM Cotton has been developed by BCS as an alternative insect-resistant and herbicidetolerant cotton. The introduction of the Bt protein Cry2Ae provides an additional measure of 

insect protection not currently available in cotton. The tolerance to glufosinate ammonium, in 

addition to the insect resistance provided by the two Cry proteins, will provide cotton growers 

with a new approach for managing lepidopteran pests of cotton, as well as herbicide-resistant 

weeds.

Current insect resistance management strategies have delayed the development of resistance to 

Bt toxins. However, in a review of GE crops, Lemaux (2009) reports that some cotton 

lepidopteran-insect resistance to Bt toxins has occurred. The availability of additional 

lepidopteran insect-resistant traits in cotton, such as that conferred by incorporation of the 

Cry2Ae protein, further reduces the likelihood of pest resistance to existing pest control methods 

(Gould, 2003). A recent study evaluated several cultivation practices which might delay the 

development of insect resistance, including the planting of refuge areas with crops not 

engineered to contain Bt (Tabashnik et al., 2008).

Glufosinate ammonium tolerance was introduced by Bayer in its LibertyLink® Cotton to provide 

cotton growers with an alternative herbicide choice. The LibertyLink®

USDA-APHIS, 2003

Cotton product was 

deregulated by APHIS in 2003 ( ) and is widely available. EPA has 

published a voluntary pesticide resistant management labeling guideline providing guidance on 

reducing or managing the potential for herbicide-resistant weeds or volunteers (Pesticide 

Registration Notice 2001-5) (US-EPA, 2001a). Glufosinate ammonium tolerance provides 

growers with another herbicide option in cotton cultivation.

TwinLinkTM Cotton, either alone or when combined by traditional breeding with other 

genetically-modified insect-resistant cotton varieties, by incorporating a new Cry protein, 

provides growers with an additional pest management option for lepidopteran-insect pest control 

and may contribute to a reduction in the likelihood of insect resistance to Bt insect-resistant 

cotton varieties. Specifically, BCS indicates that the use of TwinLinkTM Cotton will provide:

1. Improved efficacy in reduction of major insect pests of cotton, independent of weather 

conditions.

2. Combined Bt trait product for insect resistance management.

3. Additional weed control options.

4. Excellent human, animal, non-target organism, and environmental safety profile.

5. Potentially reduced pesticide use.

6. Potentially enhanced yield.

7. Potentially decreased pest management costs.
BAYER TWINLINKTM COTTON

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1.5 APHIS RESPONSE TO PETITION FOR NONREGULATED STATUS

Under the authority of the plant pest provisions of the Plant Protection Act and 7 CFR Part 340, 

APHIS has issued regulations for the safe development and use of GE organisms. As required 

by 7 CFR 340.6, APHIS must respond to petitioners who request a determination of the 

regulated status of GE organisms, including GE plants such as BCS TwinLinkTM Cotton. When

a petition for nonregulated status is submitted, APHIS must make a determination if the GE

organism is unlikely to pose a plant pest risk. If APHIS determines based on its Plant Pest Risk 

Assessment (PPRA) that the genetically engineered organism is unlikely to pose a plant pest risk, 

the genetically engineered organism is no longer subject the plant pest provisions of the Plant 

Protection Act and 7 CFR part 340.

TwinLinkTM Cotton has been field tested in the U.S. since 2005, as authorized by APHIS. Data 

were provided in the petition for field trials completed prior to the petition submission. Field test 

reports can be found in the BCS TwinLinkTM Cotton petition in Appendix 1, p.102 (Scott, 2008).

BCS has conducted 66 field trials under field release authorizations granted by USDA APHIS in 

diverse regions of the U.S., including Arizona, California, Georgia, Louisiana, Mississippi, 

North Carolina, South Carolina, and Texas. Field tests conducted under APHIS oversight allow 

for evaluation in agricultural settings under confinement measures designed to minimize the 

likelihood of persistence in the environment after completion of the field trial. Under confined 

field trial conditions, data are gathered on multiple parameters and used by applicants to evaluate 

agronomic characteristics and product performance. These data are also valuable to APHIS for 

assessing the potential for a new variety to pose a plant pest risk. The data evaluated for 

TwinLinkTM Cotton may be found in the document Determination of Plant Pest Risk for InsectResistant and Glufosinate Ammonium-Tolerant (TwinLinkTM) Cotton, Gossypium hirsutum, 

Events T304-40 x GHB119 (USDA-APHIS, 2010b).

APHIS has prepared this environmental assessment to consider the potential environmental 

effects of an agency determination of nonregulated status consistent with Council of 

Environmental Quality’s (CEQ) regulations implementing NEPA (40 CFR Parts 1500-1508),

and the USDA and APHIS NEPA implementing regulations and procedures (7 CFR 1b, and 7 

CFR Part 372) and the USDA and APHIS NEPA implementing regulations and procedures. 

This EA has been prepared in order to specifically evaluate the effects on the quality of the 

human environment1

 

1 Under NEPA regulations, the “human environment” includes “the natural and physical environment and the 

relationship of people with that environment” (40 CFR §1508.14).

that may result from the deregulation of BCS TwinLinkTM Cotton. 
BAYER TWINLINKTM COTTON

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1.6 COORDINATED FRAMEWORK REVIEW

Food and Drug Administration

TwinLinkTM Cotton (events T304-40 x GHB119) is within the scope of the 1992 FDA policy 

statement concerning regulation of products derived from new plant varieties, including those 

developed through biotechnology (US-FDA, 1992). 

Bayer has provided the FDA with information on the identity, function, and characterization of 

the genes, for TwinLinkTM Cotton, including expression of the gene products. The FDA is 

currently reviewing the information submitted by the applicant. 

APHIS considers the FDA food and feed safety and nutritional assessment determination when 

assessing potential impacts that may result from the deregulation of a GE organism. In the 

absence of a completed FDA determination, APHIS takes into consideration prior FDA reviews 

of comparable products to make a preliminary assessment of the potential impacts. 

Note that with regard to the expression of glufosinate ammonium tolerance, the gene construct in 

the Bayer TwinLinkTM Cotton is the same as that approved by the FDA in June 2003 for the 

LibertyLink® Cotton product (US-FDA, 2003). In that approval, the FDA noted that the 

transformational event in LibertyLink®

US-FDA, 2003

Cotton was not materially different in composition, 

safety, or any other relevant parameter in cotton grown, marketed, and consumed at that time 

( ). This previous FDA review will be used by APHIS to analyze the food and 

safety impacts associated with the incorporation and expression of glufosinate ammonium

tolerance in TwinLinkTM Cotton.

The FDA’s oversight of the food and safety impacts associated with the incorporation and 

expression of pesticidal substances, in this case, the Cry proteins associated with Bt, are more

limited. As discussed below, the EPA is the primary authority for the review of plantincorporated protectants.

Environmental Protection Agency

The EPA has authority over the use of pesticidal substances and plant-incorporated protectants 

under the FIFRA as amended (7 USC §136, et seq.) and the FFDCA (21 USC §301, et seq.). 

EPA is currently reviewing information submitted by the applicant on the efficacy and potential 

environmental concerns associated with the use of this product. APHIS considers the EPA’s 

regulatory assessment when assessing potential impacts that may result from the deregulation of 

a GE organism. In the absence of a completed EPA determination, APHIS takes into 

consideration prior EPA reviews of comparable products to make a preliminary assessment of 

the potential impacts. 

Note that EPA has issued a tolerance exemption for Cry1Ab protein in all crops (40 CFR 

§174.511; US-EPA, 2010d), as well as for the PAT protein (40 CFR §174.522; US-EPA, 2010g). 

A temporary exemption from the requirement of a tolerance has been issued for Cry2Ae (40 

CFR §174.530; US-EPA, 2010e). These previous EPA reviews will be used by APHIS to 

analyze the food and safety impacts associated with the incorporation and expression of the Cry 

proteins in TwinLinkTM Cotton.
BAYER TWINLINKTM COTTON

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In addition to review of the crop with plant-incorporated protectants, EPA has authority under 

FIFRA to establish pesticide use restrictions; these use restrictions are presented on pesticide 

labels which are prepared during the pesticide registration process. The development of a 

transformed cotton crop providing tolerance to glufosinate ammonium may require a change in 

the EPA-approved label for this herbicide. 

The current glufosinate ammonium label provides for its use on transformed crops expressing 

resistance to glufosinate ammonium, and specifically references products marketed under the 

trade name “LibertyLink” (BCS, 2010a). Glufosinate ammonium-tolerant cotton was first 

available in the U.S. with the introduction of LibertyLink® Cotton in 2004. Although the 

glufosinate ammonium tolerance trait expressed in TwinLinkTM cotton is the same as that 

expressed in the LibertyLink®

1.7 PUBLIC INVOLVEMENT

Cotton, the EPA is expected to publish a new label for glufosinate

ammonium that also references the TwinLinkTM product varieties. APHIS will use current 

glufosinate label as the basis for its evaluation of the potential impacts associated with the use of 

and exposure to glufosinate ammonium. 

APHIS routinely seeks public comment on draft EAs prepared in response to petitions to 

deregulate GE organisms. APHIS does this through a notice published in the Federal Register. 

The issues discussed in this EA were developed by considering public concerns, as well as issues 

raised in public comments submitted for other environmental assessments of GE organisms, 

concerns raised in lawsuits, as well as those issues that have been raised by various stakeholders. 

These issues, including those regarding the agricultural production of cotton using various 

production methods, and the environmental and food/feed safety of GE plants, were addressed to 

analyze the potential environmental impacts of TwinLinkTM Cotton. 

This EA, the petition submitted by BCS, and APHIS’s Determination of Plant Pest Risk for 

Insect-Resistant and Glufosinate Ammonium-Tolerant (TwinLinkTM) Cotton, Gossypium 

hirsutum, Events T304-40 x GHB119 (USDA-APHIS, 2010b) will be available for public 

comment for a period of 60 days (7 CFR §340.6(d)(2)). Comments received by the end of the 

60-day period will be reviewed and used to inform APHIS’s determination decision of the 

regulated status of TwinLinkTM Cotton and to assist APHIS in determining whether an 

Environmental Impact Statement is required prior to a determination of the regulated status of 

TwinLinkTM Cotton.

1.8 ISSUES CONSIDERED

As stated above, the issues considered in this EA were developed based on APHIS’s

determination to deregulate certain GE organisms; and, for this particular EA, the specific 

deregulation of TwinLinkTM Cotton. These issues include:

Cotton Production:

• Acreage and Areas of Cotton Production

• Cropping Practices

• Seed Production
BAYER TWINLINKTM COTTON

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• Organic Farming

• Specialty Cotton Production

Environmental Considerations:

• Water Resources

• Soil

• Air Quality 

• Climate Change

• Animals

• Plants

• Biological Diversity

• Gene Movement

Public Health Considerations:

• Human Health

• Worker Safety

Animal Feed

Socioeconomic Issues:

• Domestic Economic Environment at Risk

• Trade Economic Environment at Risk

• Social Environment at Risk

Other Cumulative Effects

Threatened and Endangered Species

Other U.S. Regulatory Approvals and Compliance with Other Laws
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2 AFFECTED ENVIRONMENT

The Affected Environment Section provides an overview of the use and biology of cotton, 

followed by a discussion of the current conditions of those aspects of the human environment 

potentially impacted by the deregulation of TwinLinkTM Cotton. For the purposes of this draft 

EA, those aspects of the human environment are: cotton production practices, the physical 

environment, biological resources, public health, animal feed, and socioeconomic issues.

2.1 COTTON USE AND BIOLOGY

2.1.1 Cotton Taxonomy

Cotton is a perennial plant that is cultivated as an annual crop (USDA-ERS, 2009). The 

Gossypium genus is made up of approximately 50 species, but only five species are cultivated 

worldwide (OECD, 2008). The cultivated species upland cotton (G. hirsutum) represents 97% of 

cotton crop grown in the U.S. (USDA-ERS, 2009). The balance of U.S.-grown cotton is 

American Pima, the generic name for extra-long staple (ELS) cotton, G. barbadense (Meyer et 

al., 2007; USDA-ERS, 2009). ELS is cultivated primarily in irrigated regions of California, New 

Mexico, Arizona, and Texas (Meyer et al., 2007; USDA-ERS, 2009). The three other cultivated

species are G. arboretum, G. herbaceum, and G. lanceolatum (OECD, 2008; Scott, 2008). 

Seven genomes, designated A, B, C, D, E, F, and G, are found in the Gossypium genus (Endrizzi 

et al., 1984). Diploid (i.e., two sets of chromosomes) species (2n=26) are found on all 

continents, and a few are of some agricultural importance. The A genome is restricted in 

diploids to two species (G. arboreum and G. herbaceum) of the Old World. The D genome is 

restricted in diploids to some species of the New World, such as G. thurberi. The most 

important agricultural cottons, G. hirsutum and G. barbadense, are both allotetraploids (i.e., 

hybrids containing 4 complete haploid chromosome sets representing the complete chromosome 

sets from both parent organisms) (2n=4x=52). These cultivated varieties are of New World 

origin and are presumed to be the result of an ancient interspecific hybridization between Old 

World A genomes and New World D genomes (Scott, 2008). How and when the original crosses 

occurred has been subject to much speculation. Euploids (i.e., organisms containing equal 

numbers of the haploid chromosome sets) of these plants have 52 somatic chromosomes and are 

frequently designated as AADD (they behave as disomic polyploids, i.e., have two complete sets 

of chromosomes from both original ancestors). The New World allotetraploids are peculiar in 

the genus, because the species, at least in their wild forms, grow near the ocean as invaders in the 

constantly disturbed habitats of strand and associated environs. It is from these "weedy" or 

invader species that the cultivated cottons developed (Fryxell, 1984).

Due to the difference in ploidy level (i.e., number of sets of chromosomes), G. hirsutum cannot 

cross with wild diploid cottons. G. hirsutum is readily cross-compatible, i.e., can hybridize, only 

with other tetraploid members of the tribe Gossypium, which include G. tomentosum in Hawaii, 

G. darwinii in the Galapagos Islands, G. mustelinum in northeastern Brazil, G. hirsutum and G. 

lanceolatum in tropical/subtropical America, and G. barbadense in South America, as well as 

cultivated forms of G. hirsutum and G. barbadense (Fryxell, 1984). 
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These distinctions in genetic construct are important to recognize, as the genetic differences 

directly affect the ability of cultivated cotton to interbreed with wild cotton species as well as 

wild or feral cotton. There are only two wild cotton species found in the U.S.: G. thurberi

(desert cotton), found in Arizona; and G. tomentosum (Hawaiian cotton), found in Hawaii (ITIS, 

2010; USBG, 2010; USDA-ARS, 2010a). G. tomentosum has been crossed with G. hirsutum in 

breeding programs; however, no commercial cotton is produced in Hawaii (Scott, 2008; USDANASS, 2010c). Feral populations of upland cotton (G. hirsutum) can be found in southern 

Florida (USDA-FS, 2010). These populations are apparently self-sustaining because there is no 

commercial production of cotton in this region (Scott, 2008; USDA-NASS, 2010c). 

2.1.2 Cotton Use

Cotton (Gossypium spp.) is a member of the Malvaceae family and is the world’s most widely 

grown fiber crop, accounting for over 40% of the total world fiber use (Meyer et al., 2007). 

Cotton has been cultivated for its fiber for several thousand years (Scott, 2008). Other cotton 

products, such as cottonseed oil, cake, and cotton linters, are by-products of cotton fiber 

production (Scott, 2008). 

2.2 AGRICULTURAL PRODUCTION OF COTTON

2.2.1 Acreage and Areas of Cotton Production

Cotton is cultivated mostly in subtropical and warm temperate zones (OECD, 2008). 

Temperature is the main climatic factor determining the geographic range in which cotton can be 

grown, but cultivation is also dependent upon high light intensity, good soil moisture, and soil 

fertility (Meyer et al., 2007; OECD, 2008). 

Cotton is mainly produced in China, India, U.S., Pakistan, Brazil, and Uzbekistan, with these 

five countries contributing nearly 83% of world production (Table 2-1) (USDA-FAS, 2010a). 

The total planted area throughout the world in 2007-2008 was 33.2 million hectares, for a 

production of 116 million bales (approximately 26 million metric tons) (USDA-FAS, 2010a). 

The U.S. is the third largest producer of cotton fiber. 

Table 2-1: Cotton Fiber: World Production in Select Countries, 2006 to 2010/11 

(estimated) (1,000 metric tons)

Country

Year

2006/2007 2007/2008 2008/2009 2009/2010 2010/2011 (est.)

China 7,729 8,056 7,991 6,967 6,858

India 4,746 5,225 4,921 5,051 5,661

United States 4,700 4,182 2,790 2,654 4,109

Pakistan 2,090 1,872 1,894 2,090 2,025

Brazil 1,524 1,602 1,193 1,165 1,524

Uzbekistan 1,165 1,165 1,002 849 1,045

Australia 294 139 327 386 718

Other 4,258 3,814 3,210 2,907 3,463

Total 26,507 26,056 23,326 22,070 25,404

Source: (USDA-FAS, 2010a)
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In the U.S. for the 2010 production year, cotton was grown on 4.4 million hectares 

(approximately 10.8 to 10.9 million acres) (USDA-NASS, 2010b). In the U.S., cotton is 

produced in 17 southern states identified as the Cotton Belt: Alabama, Arizona, Arkansas, 

California, Florida, Georgia, Kansas, Louisiana, Mississippi, Missouri, New Mexico, North 

Carolina, Oklahoma, South Carolina, Tennessee, Texas, and Virginia (Meyer et al., 2007; 

USDA-NASS, 2010c). The major cotton producing states are Texas (5.4 million acres), Georgia 

(1.3 million acres), Arkansas (0.540 million acres), Mississippi (0.420 million acres), North 

Carolina (0.545 million acres), and Tennessee (0.387 million acres) (USDA-NASS, 2010c). 

Cotton acreage in the U.S. rose slightly during the first half of the 2000s, continuing a multidecade trend. In the 1970s and 1980s, the area planted for cotton averaged about 12 million 

acres (USDA-ERS, 2009). The area planted rose to about 14 million acres in the 1990s and 

averaged over 14.5 million acres during the first half of the 2000s, representing an increase of 

20% over the 1970s and 1980s acreage (USDA-ERS, 2009). Since 2006, however, U.S. cotton 

planted acreage has been considerably lower, as prices have favored the planting of alternative 

crops such as corn and soybeans (USDA-ERS, 2009). All cotton growing regions have 

experienced significant declines compared with the first half of the 2000s (USDA-ERS, 2009).

GE varieties of cotton have been very rapidly adopted. In 1996, when Bt cotton was first 

commercially introduced, initial plantings were estimated at 1.7 million acres (Benbrook, 2009). 

Of the approximate 11 million acres planted in cotton in 2010, about 93% (10.2 million acres) 

were GE cotton. Of this, 73% of the GE cotton acreage was GE insect-resistant (Bt) cotton, and 

78% was herbicide-tolerant (USDA-ERS, 2010a).

2.2.2 Cropping Practices: Crop Rotation and Pesticide Use

Growers can choose from many cultivars of cotton marketed by companies that produce seed,

including GE varieties (USDA-AMS, 2010a). Planting of cotton occurs after any danger of frost 

has passed and soil temperatures are at least 14o

C (57oF) (OECD, 2008). Planting dates vary 

depending on the region, but generally range from early March in southern Texas to early May 

or June in the northern areas of the Cotton Belt. Cotton requires 180 to 200 days from planting 

to maturity (OECD, 2008). Therefore, cotton planted in March or April is ready for harvest in 

September. 

Crop rotations (successive planting of different crops on the same land) are used to optimize soil 

nutrition and fertility and reduce pathogen loads (Gazaway et al., 2007; University of California 

IPM Online, 2008a). Cotton is often rotated with other crops in order to control various cotton 

pests including nematodes, verticillium wilt, seedling diseases, and pink bollworm (University of 

California IPM Online, 2008a). Rotation crops may include small grains, cowpea, corn, 

sorghum, alfalfa, onions or garlic, and nematode-resistant tomatoes. Rotations may last for two 

or three years. Winter cover crops are also utilized in cotton. 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). 

Cotton production in the U.S. is highly mechanized and involves the extensive use of agronomic 

inputs and technology (USDA-APHIS, 2010a). The cost of production includes annual direct 
BAYER TWINLINKTM COTTON

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costs (seed, fertilizer, chemicals, irrigation, etc.), annual fixed costs (depreciation on equipment), 

and annual land rent (Hogan et al., 2005). These costs will vary depending on region and 

practices used. In 2009, average per acre costs for U.S. cotton growers for cotton seed, fertilizer 

(commercial fertilizers, soil conditioners, and manure), and chemicals (including pesticides and 

herbicides) accounted for 54% of the total dollars spent per planted acre or $232 per acre 

(USDA-ERS, 2010b).

Worldwide, cotton has proven vulnerable to the attack of many insect species. In the U.S., the 

cotton industry has consistently relied heavily on insecticide use strategies to manage arthropod 

pests (Gianessi and Carpenter, 1999). Resistance to commonly used insecticides (pyrethroids, 

organophosphates, and carbamates) has led to a need for new pesticide chemistries or other novel 

approaches, such as the use of sterile insects, pathogens, and transgenic cotton (Gianessi and 

Carpenter, 1999). Pest management in agricultural crop production is achieved through various 

management methods, including chemical (pesticides), cultural (mechanical cultivation, 

planting/harvesting dates, crop rotation, etc.), biological (antagonistic organisms), and 

bioengineering (primarily herbicide-tolerant and insect-resistant crops) (USDA-ERS, 2005a). 

GE insect-resistant cotton has been focused on incorporating Bacillus thuringiensis (Bt) Cry 

endotoxin protein based plant incorporated protectants (Stewart, 2007).

The most damaging insect pests of cotton attack the cotton square (the flower bud) or the cotton

boll (the ovary containing developing seeds and fibers) (Gianessi and Carpenter, 1999). There 

are over 20 economically important pests of cotton. The major insect pests of U.S. cotton in 

2009 are listed in Table 2-2 (Williams, 2010). Thrips (Frankliniella occidentalis), lygus (Lygus 

hesperus), and the budworm/bollworm complex each infested more than half of the U.S. cotton 

crop. The budworm/bollworm complex, which infested 56% of the acreage, was the third 

leading cause of yield loss due to insects. It is referred to as a complex because the larvae of 

these moth insects are identical when observed in the field (Gianessi and Carpenter, 1999). The 

complex consists of the cotton bollworm (Helicoverpa zea) and tobacco budworm (Helicoverpa 

virescens) whose small larvae feed on smaller squares and terminal buds, but whose older, larger 

larvae devour buds, flowers, and bolls, consuming both lint and seed (Gianessi and Carpenter, 

1999). In 2009, the complex reduced yields by 0.486% or 91,119 bales of cotton (Williams, 

2010). Bt cotton provides good control over bollworm and tobacco budworm, as well as loopers, 

fall armyworm, and beet armyworm (Stewart, 2007).

Table 2-2: Cotton Pests Ranked in Order of Bales Lost, Presenting Percent U.S. Cotton 

Yield Reduction, Number of Cotton Acres Infested, Percent of U.S. Cotton 

Infested, Bales Lost, in 2009

Pest

Percent U.S. Cotton 

Yield Reduction 

Attributed to Pest

Acres Infested 

with Pest

Percentage of 

Cotton Acreage 

Infested Bales Lost

Thrips 0.713% 7,437,609 94.49% 138,207

Lygus 0.614% 4,209,086 53.47% 126,871

Bollworm/Budworm 0.486% 4,376,640 55.60% 91,119

Stink Bugs 0.371% 3,265,604 41.49% 79,327

Fall Armyworm 0.113% 1,835,299 23.32% 20,238
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Pest

Percent U.S. Cotton 

Yield Reduction 

Attributed to Pest

Acres Infested 

with Pest

Percentage of 

Cotton Acreage 

Infested Bales Lost

Spider Mites 0.099% 2,022,705 25.70% 21,673

Cotton Fleahoppers 0.093% 1,490,760 18.94% 15,598

Clouded Plant Bugs 0.038% 452,752 5.75% 8,300

Aphids 0.030% 3,851,114 48.93% 6,456

Silverleaf Whitefly (Bemisia) 0.008% 289,731 3.68% 2,245

Beet Armyworm 0.004% 703,067 8.93% 643

Other Insects 0.003% 62,193 0.79% 668

Boll Weevil 0.002% 116,247 1.48% 400

Grasshoppers 0.001% 1,128,763 14.34% 266

Banded Wing Whitefly 0.001% 524,519 6.66% 249

Cutworms 0.001% 386,007 4.90% 200

Loopers 0.000% 808,131 10.27% 12

Saltmarsh Caterpillars 0.000% 487,934 6.20% 0

Cotton Leaf Perforator 0.000% 2,585 0.03% 1

Pink Bollworm 0.000% 81,211 1.03% 0

European Cornborer 0.000% 655 0.01% 0

Southern Armyworms 0.000% 68,798 0.87% 0

Source: (Williams, 2010)

2.2.3 Seed Production 

On an annual basis, certified seed of all varieties of cotton combined must be able to plant over 

10 million acres in the U.S. alone (USDA-NASS, 2010b) This requires between 60,000 and 

70,000 short tons of planting seed (National Cottonseed Products Association, 2011). 

Public cotton breeding programs began in California in 1898 and private programs began in the 

early 1920s (Marra and Martin, 2007). Cotton was one of the earliest crops for which the 

Association of Official Seed Certifying Agencies (AOSCA) developed seed certification 

standards to maintain genetic purity of cotton varietal seed and specialty cotton crops by 

precluding gene flow and preventing cross pollination between species and varieties (AOSCA, 

2010b; Wozniak, 2002). 

In a seed certification program, classes of seed are identified to designate the seed generation 

from the original breeder source (Hartman and Kester, 1975). Foundation seed, Registered seed, 

and Certified seed production is controlled by public or private seed certification programs (see, 

e.g., AOSCA, 2010b). The original seed breeder seed stock is controlled by the developer of the 

variety (Adam, 2005; Hartman and Kester, 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; 
BAYER TWINLINKTM COTTON

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Hartman and Kester, 1975). The Certified (or Select) seed is then sold to growers through 

commercial channels (Adam, 2005; Hartman and Kester, 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 (Hartman and Kester, 1975; Wozniak, 2002). The isolation distance for 

Foundation, Registered, and Certified seeds, as dictated by the USDA Agricultural Marketing 

Service's (AMS) Federal Seed Act in 7 CFR Part 201.76, is 1,320, 1,320, and 660 feet, 

respectively (USDA-AMS, 2010c). During the growing season, seed certification agencies will 

monitor the fields for off-types, other crops, weeds, and disease (Wozniak, 2002). 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, 2002). Further discussion of cross-pollination, gene transfer, and 

weediness is presented in Subsection 2.4.4, Gene Movement. 

2.2.4 Organic Farming

In the U.S., only products produced using specific methods and certified under the USDA 

National Organic Program (NOP) definition of organic farming can be marketed and labeled 

as “organic” (Ronald and Fouche, 2006; USDA-AMS, 2010b). The NOP is administered by 

USDA’s AMS. 

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 (Ronald and Fouche, 2006). 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,...

Excluded methods are then defined at 7 CFR §205.2 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. Such 

methods include cell fusion, microencapsulation and macroencapsulation, and 

recombinant DNA technology (including gene deletion, gene doubling, 

introducing a foreign gene, and changing the positions of genes when achieved by 
BAYER TWINLINKTM COTTON

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recombinant DNA technology). Such methods do not include the use of 

traditional breeding, conjugation, fermentation, hybridization, in vitro 

fertilization, or tissue culture.

The NOP has recognized the feasibility of protecting organically-produced crops from accidental 

contamination by GE crops by requiring that organic production plans include practical methods 

to protect organically-produced crops—

Organic crops must be protected from contamination by prohibited substances 

used on adjoining lands (for example, drifting pesticides, fertilizer-laden runoff 

water, and pollen drift from genetically engineered...) (NCAT, 2003).

Organic farming operations, as described by the NOP, require organic production operations to 

have distinct, defined boundaries and buffer zones to prevent unintended contact with 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 prohibition on the use of 

excluded methods. In NOP organic systems, the use of GE crops, such as TwinLinkTM Cotton, 

is excluded (USDA-AMS, 2010b).

The organic plan used as the basis for organic certification should include a description of 

practices used to prevent or reduce the likelihood of unwanted substances, like GE pollen or 

seed, at each step in the farming operation, such as planting, harvesting, storing, and transporting 

the crop (Krueger, 2007; Riddle, 2004). Organic plans should also include how the risk of GE 

pollen or co-mingling of seed will be monitored (Krueger, 2007; Riddle, 2004). Farmers using 

organic methods are requested to let neighboring farmers know that they are using organic 

production practices and request that the neighbors also help the organic farmer reduce 

contamination events (Krueger, 2007; NCAT, 2003). 

Organic cotton provides price premiums for the grower (Guerena and Sullivan, 2003). 

Organic production begins with certified organically grown seed (Guerena and Sullivan, 

2003). Certified organic cotton acreage is a relatively small percentage of overall cotton 

production in the U.S. The most recently available data show 15,377 acres of certified 

organic cotton production in 2008 (USDA-ERS, 2010c). This is 0.16% of the total 9.41 

million acres of cotton planted in 2008 (USDA-ERS, 2009). Bayer CropScience FM 958, 

FM989, and ADF 2485 were the predominate varieties planted in 2010 by organic cotton 

producers (USDA-AMS, 2010b).

2.2.5 Specialty Cotton Production

Several specialty cottons are cultivated in the U.S., including ELS (G. barbadense) Pima 

varieties, specialty long-staple upland cotton (G. hirustum) Acala varieties, organic cotton, and 

naturally colored cotton (Lee, 1996; USDA-ERS, 2009). Historically, ELS cotton acreage has 

ranged from a low of 63,000 acres in 1983 to a high of 377,000 acres in 1989 (National Cotton 

Council of America, 2010). This represented 0.83% and 3.5% of the total cotton acreage planted 

for those years, respectively (National Cotton Council of America, 2010). Naturally colored 
BAYER TWINLINKTM COTTON

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cotton acreage was reported to be 4,000 acres in 1992 (Dickerson et al., 1999) and between 5,000 

and 7,000 acres in 1995 (Lee, 1996). 

Similar to the production of conventional seed, industry quality standards for specialty crop 

products have led these seed producers and growers to employ a variety of techniques to ensure 

that their products are not pollinated by or commingled with conventional or genetically 

engineered crops (Bradford, 2006). Common 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 (NCAT, 2003; Wozniak, 2002). The Federal 

Seed Act Regulations provide additional details on Certified seed production (see 7 CFR 201, et 

seq). Field monitoring for off-types, other crops, weeds, disease etc. is also carried out by 

company staff and state crop improvement associations (Bradford, 2006). Seed handling 

standards are established by AOSCA to reduce the likelihood of seed source mixing during 

planting, harvesting, transporting, storage, cleaning, and ginning (AOSCA, 2004). In general, 

the conventional management practices used for conventional seed production are sufficient to 

meet standards for the production of specialty crop seed (Bradford, 2006).

2.3 PHYSICAL ENVIRONMENT

The use of fertilizers, pesticides, and water may affect segments of the environment including, 

but not limited to: waterways by increases in nutrient pollution; biodiversity because pesticide 

inputs cause species changes; the water table because of excessive irrigation practices; and 

productivity of cropland because irrigation increases salinity (Hoeft et al., 2000). Sediment,

siltation, nutrients, pesticides, salinity, and pathogens are primary agricultural pollutants (USDAERS, 2005b). 

2.3.1 Water Resources

Cotton has been developed as a drought-tolerant crop; cotton production water use varies 

according to the growing environment (Cotton Incorporated, 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 Incorporated, 2010a). 

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 Incorporated, 2010a). 

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 Incorporated, 2010a). In these areas, cotton has been displaced by 

higher value crops and land uses (Cotton Incorporated, 2010a). 

Conservation tillage and no-till practices have been shown to minimize surface water runoff and 

soil erosion and to improve soil quality by increasing the soil organic matter that helps bind soil 

nutrients and prevent their loss to runoff, erosion, and leaching (Leep et al., 2003). This decrease 

in soil erosion carries a corresponding decrease in non-point source surface water pollution of 
BAYER TWINLINKTM COTTON

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fertilizer and pesticides (Cotton Incorporated, 2010a, 2010c). Precision agriculture, a practice 

carefully managing nutrients and chemical applications, also ensures that inputs are used by the 

crop and are not entering ground or surface waters (Cotton Incorporated, 2010a). Precision 

agriculture practices may include computer models to predict water use based on plant growth 

stage, weather, soil moisture probe data collection, and thermal infrared imagery of plant leaf 

temperature (Cotton Incorporated, 2010a). Each of these practices has the potential to reduce 

soil-laden water runoff (USDA-NRCS, 2006b). 

2.3.2 Soil

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).

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 to control late emerging weeds (Cotton Incorporated, 2010c). This 

practice results in soil loss to wind and water erosion. 

Conservation practices have been developed to reduce field tillage and thus reduce the 

corresponding soil loss (USDA-NRCS, 2006a). As conservation practices are adopted, 

there are increases in soil organic matter that helps bind soil nutrients and corresponding 

significant reductions over time in the loss of cropland soil from runoff, erosion, and 

leaching (Leep et al., 2003; USDA-NRCS, 2006a, 2006b). Total soil loss on highly erodible 

croplands and non-highly erodible croplands decreased from 462 million tons per year to 

281 million tons per year or by 39.2% from 1982 to 2003 (USDA-NRCS, 2006b). This 

decrease in soil erosion carries a corresponding decrease in non-point source surface water 

pollution of fertilizer and pesticides (Cotton Incorporated, 2010a, 2010c). The reduction in soil 

erosion is also attributed to a decrease in the number of acres of highly erodible cropland 

being cultivated (USDA-NRCS, 2006b). 

Over the last 10 years, cotton cultivation has contributed to this reduction in soil loss 

through a shift towards soil conservation practices (Cotton Incorporated, 2010c). 

Conservation practices adopted in cotton cultivation include use of seed treatment 

fungicides, herbicides, and herbicide-tolerant cotton varieties, each of which provide for the 

control of cotton disease and weeds with minimal tillage (Cotton Incorporated, 2010c; 

USDA-NRCS, 2006b). In the U.S., conservation tillage in cotton fields has increased from 

0.5 million acres in 1990 to about 2.75 million acres in 2004; in 2008, approximately 67% 

of cotton growers reported adopting some form of conservation tillage (Cotton Incorporated, 

2010c). Increases in total acres dedicated to conservation tillage have been attributed to an 

increased use of GE seed which eliminates the need for mechanical weed control (Alabama 

Cooperative Extension System, 1996; McClelland et al., 2000; Towery and Werblow, 2010; 

USDA-NRCS, 2006b).

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. 
BAYER TWINLINKTM COTTON

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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 water-holding 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 cotton is primarily through the use of herbicides

(Alabama Cooperative Extension System, 1996). Preplant “burndown” herbicides such as 

paraquat and glyphosate and some pre-emergent herbicides make up the primary weed 

control methods. Winter and cover crops are also utilized in conservation tillage for the

purpose of suppressing weeds (Alabama Cooperative Extension System, 1996). Wheat and 

rye are commonly employed 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 (Alabama Cooperative Extension System, 1996; McClelland et 

al., 2000).

In some regions, conservation tillage is required. Farmers, including cotton growers, 

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) (USDAERS, 2010d). 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, 2010d).

The adoption of Bt cotton, which may require reduced quantities of pesticides, may benefit soil

quality by reducing the risks associated with environmental spills or misapplications of chemical 

insecticides to the soil, and reducing the frequency of application. Reduced insecticide 

applications also mean a reduction in the number of trips across the field with heavy farm 

equipment which contributes to soil compaction, especially when the soil is wet. The number of 

acre-treatments per year of budworm/bollworm insecticides declined from over 10 million to less 

than 3 million between the years 1996 and 2007 (USDA-NASS, 2008). This is attributed to the 

widespread adoption of Bt cotton, introduced commercially in 1996, which increased from 1.73

million acres of cotton planted to 7.6 million acres in the U.S. during the same time period 

(Benbrook, 2009).

2.3.3 Air Quality

Agricultural air emission sources include smoke from agricultural burning, vehicle exhaust 

associated with equipment used in tillage and harvest, suspended soil particulates associated with 

tillage, pesticide drift from spraying, and nitrous oxide emissions from the use of nitrogen 

fertilizer (Aneja et al., 2009; Hoeft et al., 2000; US-EPA, 2010b; USDA-NRCS, 2006c). These 

agricultural activities individually have the potential to cause negative impacts to air quality.

Aerial application of pesticides may cause air quality impacts from drift and diffusion. 

Pesticides may volatilize after application to soil or plant surfaces and may also move as 

constituents of entrained materials in wind eroded soils (Vogel et al., 2008). 
BAYER TWINLINKTM COTTON

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Many of the conservation plans and practices being developed by cotton growers to comply with 

the Conservation Compliance and Sodbuster programs have an air quality focus which target 

reductions in air emissions from agricultural operations (Cotton Incorporated, 2010c; USDANRCS, 2006a). Practices to improve air quality include conservation tillage, residue 

management, wind breaks, road treatments, burn management, prunings shredding, feed 

management, manure management, integrated pest management, chemical storage, nutrient 

management, fertilizer injection, chemigation and fertigation (inclusion in irrigation systems), 

conservation irrigation, scrubbers, and equipment calibration (USDA-NRCS, 2006a). 

Conservation tillage practices resulting in improved air quality include: fewer tractor passes 

across a field, thus decreasing dust generation and tractor emissions; and an increase in surface 

plant residues and untilled organic matter which physically hold the soil in place and reduce 

wind erosion (Baker et al., 2005; Cotton Incorporated, 2010d; USDA-NRCS, 2006a). The 

USDA has estimated that by 2006, the adoption of conservation management plans in the San 

Joaquin Valley of California had reduced air emissions by 34 tons daily, or more than 20% of the 

total emissions attributed to agricultural practices (Baker et al., 2005; USDA-NRCS, 2006a). 

2.3.4 Climate Change

Agriculture, including land-use changes for farming, is responsible for an estimated 6% of all 

human-induced greenhouse gases (GHG) in the U.S. (US-EPA, 2010b). Emissions of GHG 

released from agricultural equipment (e.g., irrigation pumps and tractors) include carbon 

monoxide, nitrogen oxides, reactive organic gases, particulate matter, and sulfur oxides (USEPA, 2010b). Agricultural soil management practices, including nitrogen-based fertilizer 

application and cropping practices, are the largest source of U.S. nitrous oxide (N2O) emissions; 

croplands account for 69% of the total N2 USEPA, 2010bO emissions attributable to agricultural land uses (

). Agriculture sources of methane emissions are primarily associated with enteric 

emissions of gas from cattle and manure management. Carbon dioxide is also a significant GHG 

gas associated with several agricultural practices, including land uses and energy consumption 

(US-EPA, 2010b). 

Tillage contributes to the release of GHG because of the loss of carbon dioxide (CO2

Baker et al., 2005

) to the 

atmosphere, and the exposure and oxidation of soil organic matter ( ). The 

carbon footprint for cotton production has been estimated to be approximately 300 pounds of 

carbon equivalent emission per acre (Nelson et al., 2009). The carbon footprint of cotton is 

directly affected by the associated cultivation practices. In a no-tillage production environment, 

if credit is taken for the sequestration of carbon in soil, cotton actually stores more carbon than is 

emitted from the production (Cotton Incorporated, 2010d). Reduced tillage increases 

sequestration rates of carbon emissions in soils, with the estimated increase to be as high as 400 

pounds of carbon per acre per year (Causarano et al., 2006). 

The contribution of agriculture to climate change is largely dependent on the production 

practices employed to grow various commodities, the region in which the commodities are 

grown, and the individual choices made by growers. For example, emissions of nitrous oxide, 

produced naturally in soils through microbial nitrification and denitrification, can be dramatically 

influenced by fertilization, introduction of grazing animals, cultivation of nitrogen-fixing crops 

and forage, retention of crop residues (i.e., no-till conservation), irrigation, and fallowing of land 

(US-EPA, 2010b). These same agricultural practices can influence the decomposition of carbon-
BAYER TWINLINKTM COTTON

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containing organic matter sequestered in soil, resulting in conversion to carbon dioxide loss to 

the atmosphere (US-EPA, 2010b). Conversion of crop land to pasture results in an increase in 

carbon and nitrogen sequestration in soils (US-EPA, 2010b). 

The EPA has identified regional differences in GHG emissions associated with agricultural 

practices on different soil types, noting that carbon emission rates differ between mineral soils 

and organic soils (US-EPA, 2010b). Mineral soils contain from 1 to 6% organic carbon by 

weight in their natural state, whereas organic soils may contain as much as 20% carbon by 

weight (US-EPA, 2010b). In mineral soils, up to 50% of the soil organic carbon can be released 

to the atmosphere on the initial conversion, however, over time, the soil establishes a new 

equilibrium that reflects a balance between carbon inputs from decaying plant matter and organic 

amendments and carbon losses from microbial decomposition (US-EPA, 2010b). Organic soils, 

with their depth and richness in carbon content, continue to release carbon to the atmosphere for 

a longer period of time (US-EPA, 2010b). The EPA has estimated that mineral soil-based 

cropland areas sequestered over 45.7 Tg CO2 Eq1 in 2008, as compared with carbon emissions 

from organic soil-based croplands of 27.7 Tg CO2 Eq (US-EPA, 2010b). The adoption of 

conservation tillage, particularly in the Midwest regions with mineral soil shows the highest rates 

of carbon sequestration (US-EPA, 2010b). 

Changes in agriculture-related GHG production will not be significant unless large amounts of 

crop plantings produce changes in measureable concentrations (USDA-APHIS, 2010a). For 

example, the EPA has identified a net reduction in the sequestration of carbon in soil over an 18-

year time scale, which it attributes to the declining influence of the Conservation Reserve 

Program which had encouraged growers to take marginal lands out of production (US-EPA, 

2010b). To a certain extent, the EPA also noted that adoption of conservation tillage resulted in 

increases in carbon sequestration on those croplands (US-EPA, 2010b). The highest rates of 

carbon sequestration in mineral soils occurred in the Midwest, which is the region with the 

largest area of cropland managed with conservation tillage (US-EPA, 2010b). This is in contrast 

to the highest emission rates from organic soils noted in the southeastern coastal region, the areas 

around the Great Lakes, and the central and northern agricultural areas along the West Coast 

(US-EPA, 2010b). 

One outcome of the potential effects of agriculture on climate change is the potential effect of the 

climate change on agriculture. In response to climate change, the current range of weeds and 

pests of agriculture is expected to increase. Current agricultural practices will be required to 

change in response to these changes in the ranges of weeds and pests of agriculture (IPCC, 

2007). 

Climate change may potentially provide a positive impact to agriculture in general. The 

Intergovernmental Panel on Climate Change (IPCC) predicts that potential climate change in 

 

1 The global warming potential of greenhouse gases are measured against the reference gas CO2, and are reported as 

teragrams (or million metric tons) of CO2 Equivalent, expressed as Tg CO2 Eq.
BAYER TWINLINKTM COTTON

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North America may result in an increase in crop yield by 5-20% for this century (IPCC, 2007). 

However, this positive impact will not be observed across all growing regions. The IPCC report 

notes that certain regions of the U.S. will be negatively impacted because the available water 

resources may be substantially reduced. Note that the extent of climate change effects on 

agriculture is highly speculative. Nevertheless, North American production is expected to adapt 

to climate change impacts with improved cultivars and responsive farm management (IPCC, 

2007). 

2.4 ANIMAL AND PLANT COMMUNITIES

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. The GE

crop systems provide opportunities to optimize the introduction and implementation of these 

practices, and have the potential to create more of these benefits. 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.

2.4.1 Animals

Intensive agricultural lands, such as those used in crop production, usually have low levels of 

biodiversity compared with adjacent natural areas. 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 (Lovett et al., 2003). However, the 

implementation of better cropland management strategies can increase the value of crop fields to 

wildlife (Sharpe, 2010). Some of these strategies are noted below.

• 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 IPM Online, 2008a). Reduced pesticide use 

has a direct positive effect on wildlife by reducing the direct exposure of birds, mammals, 

and fish to pesticides. Indirect benefits include less alteration of suitable wildlife habitat 

and an available food supply of insects for insectivores (Palmer and Bromley, 2010; 

Sharpe, 2010). Crop rotations with legumes and small grains have been shown to provide 

excellent wildlife nesting cover, food, and brood-rearing habitat for quail in North 

Carolina (Sharpe, 2010).

• Field edges can be managed to promote wildlife. These borders are often the least 

productive areas in a farm field and in some cases, the cost of producing crop areas along 

field edges exceeds the value of the crop produced (Sharpe, 2010). Allowing field edges 

to return to volunteer vegetation does not contribute to major pest problems in the crop 

field itself (Sharpe, 2010). Volunteer border vegetation, such as ragweed, goldenrod, 
BAYER TWINLINKTM COTTON

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asters, and forbs, quickly develops into nesting and brood habitat for quail and a 

multitude of songbirds (Sharpe, 2010). Research conducted at North Carolina State 

University and the North Carolina Wildlife Resources Commission found that quail 

populations doubled when field borders were used (Sharpe, 2010). 

• Contour-strip cropping is another management practice that can be used to promote 

wildlife habitat. This practice alternates strips of row crops with strips of solid stand 

crops (i.e., grasses, legumes, or small grains) with the strips following the contour of the 

land (Sharpe, 2010). The primary purpose of contour-strip cropping is to reduce soil 

erosion and water runoff, but the solid stand crop also provides a nesting and roosting 

cover for wildlife (Sharpe, 2010). 

• Drainage ditches, hedgerows, riparian areas, and adjacent woodlands to a cotton field 

also contribute to wildlife populations. Ditch banks, for example, function as narrow 

wetlands that provide nesting sites and cover, serve as wildlife corridors, and provide 

areas for the wildlife to occupy when crop fields lack cover (Sharpe, 2010). Ditches have 

been shown to support birds, rodents, reptiles, furbearers, amphibians, fish, and aquatic 

organisms (Sharpe, 2010). Minimizing pesticide exposure of ditches, aquatic habitats, 

border areas, strip-crop areas, and non-crop habitats may help protect fish and wildlife 

resources (Palmer and Bromley, 2010). 

Although many of the invertebrate organisms found in cotton-producing areas are 

considered pests, such as the cotton bollworm and tobacco budworm, most invertebrates are 

considered beneficial (University of Arkansas Cooperative Extension Service, 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 are the pollinators. Major pollinators of G. 

hirsutum are bumble bees (Bombus spp.), black bees (Melissodes spp.), and honey bees (Apis 

mellifera) (McGregor, 1976). Pollinators of G. tomentosum are principally moths (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).

2.4.2 Plants

The landscape surrounding a cotton field varies depending on the region. In certain areas, 

cotton fields may be bordered by other cotton (or any 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 (USDA-APHIS, 2010a).

Weed control programs are important aspects of cotton cultivation. In this context, weeds are 

those plants which, when growing in the cotton field, compete with the cotton for space, water, 

nutrients, and sunlight, and may thus include native species (University of California IPM 

Online, 2009c). Weeds also interfere with harvesting equipment and can stain lint (USDAAPHIS, 2010a). 
BAYER TWINLINKTM COTTON

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Cotton is susceptible to weeds because it is easily outgrown during its early season growth 

and total crop failure can occur if weeds are not properly controlled (Alabama Cooperative 

Extension System, 1996). Weed control typically involves an integrated approach that 

includes herbicides, crop rotation, weed surveillance, and weed monitoring (University of 

California IPM Online, 2009b). Crop rotation is an important component of a successful 

weed management program in cotton cultivation (University of California IPM Online, 

2009b). If a crop is cultivated year after year in the same fields, with the same cultivation 

practices followed, there is a very good chance that one or more weed species will increase 

in these fields (University of California IPM Online, 2009b). It is important that cotton 

cultivation practices employ a variety of cultural practices, as well as chemical controls 

(University of California IPM Online, 2009b). 

The types of weeds in and around a cotton field depend on the immediate area in which the 

cotton is planted. Those weed species also vary depending on the geographic region in 

which the cotton is planted (USDA-APHIS, 2010a). For example, California has over 50 

common weeds found in cotton (University of California IPM Online, 2009b). Common 

weeds in cotton include annual and perennial grasses (monocots), broad-leaf weeds (dicots), 

and sedges (Cyperus spp.). To assist growers in managing weeds, individual states, 

typically through their state agricultural extension service, will list the prevalent weeds of a 

crop and what is the most effective means for their control. For example, common weeds in 

California cotton and recommended herbicidal control can be found at University of 

California IPM Online (2009b). 

Herbicide-tolerant cotton provides several weed management advantages to the growers. Broad 

spectrum post-emergent herbicides, such as glufosinate ammonium, provide control of weeds 

early in the cultivation cycle, minimizing competition in the fields, and providing optimal 

conditions for cotton growth (University of California IPM Online, 2009b). Applications of 

over-the-top post-emergent broad spectrum herbicides to an herbicide-tolerant crop allow the 

grower to decrease the overall use of herbicides before cultivation, reduce use of soil-applied 

herbicides, and streamline field cultivation activities for weed control (Marra and Martin, 2007; 

O'Sullivan and Sikkema, 2004). Production costs decrease because growers apply fewer 

herbicides and field cultivation requirements are reduced (University of California IPM Online, 

2009b). 

Herbicide-tolerant cotton has the potential to impact the cultivation of other crops in the same 

fields in later years. Cotton is periodically seen as a volunteer in soybeans, either when cotton 

seeds have successfully overwintered or in fields where a failed cotton crop is replanted to 

soybeans (Stewart et al., 2003). Cotton volunteers are limited by the geography in which they 

are initially planted; cotton does not survive as a perennial where freezing temperatures are 

reached in the winter (Scott, 2008). These cotton volunteers typically do not reduce crop yield,

but can act as reservoirs for insect pests of cotton (Stewart et al., 2003). Successful control of 

cotton volunteers, including herbicide-resistant varieties, is accomplished through using various 

combinations of herbicides (Miller et al., 2004; Stewart et al., 2003). 
BAYER TWINLINKTM COTTON

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2.4.3 Biological Diversity

Biodiversity refers to all plants, animals, and microorganisms interacting in an ecosystem 

(Wilson, 1988). Among other benefits, biodiversity provides valuable genetic resources for crop 

improvement (Harlan, 1975) and also provides other functions beyond food, fiber, fuel, and 

income. These include pollination, genetic introgression, biological control, nutrient recycling, 

competition against natural enemies, soil structure, soil and water conservation, disease 

suppression, control of local microclimate, control of local hydrological processes, and 

detoxification of noxious chemicals (Altieri, 2000). The loss of biodiversity results in a need for

costly external inputs in order to provide these functions to the crop (Altieri, 2000). 

The degree of biodiversity in an agroecosystem depends on four primary characteristics: 1) 

diversity of vegetation within and around the agroecosystem; 2) permanence of various crops 

within the system; 3) intensity of management; and 4) extent of isolation of the agroecosystem 

from natural vegetation (Altieri, 1999). The reintroduction of woodlots, fencerows, hedgerows, 

wetlands, etc. is one way to reintroduce biodiversity into large scale monocultures. Some 

enhancement strategies include intercropping (the planting of two or more crops simultaneously 

to occupy the same field), agroforestry, crop rotations, cover crops, no-tillage, composting, green 

manuring (growing a crop specifically for the purpose of incorporating it into the soil in order to 

provide nutrients and organic matter), addition of organic matter (compost, green manure, animal 

manure, etc.), and hedgerows and windbreaks (Altieri, 1999). To some degree these practices 

are being utilized by cotton growers to increase biodiversity (Cotton Incorporated, 2010e). 

The use of genetically modified cotton affects biological diversity by: 1) providing the 

opportunity to use ecological management practices that enhance habitat creation and 2) 

decreasing the use of pesticides which in turn, limits the impact on the floral and faunal 

communities that can potentially inhabit the fields and immediate surroundings. The use of notill, cover crops, crop rotation, intercropping, and good ditch/border/hedgerow management 

contributes to biodiversity in and around cotton fields (Palmer and Bromley, 2010; Sharpe, 

2010). 

Habitat preservation and biodiversity, as well as cotton production, have benefited from modern 

cotton technology. It is now possible to grow 50% more cotton on the same land required 40 

years ago (Cotton Incorporated, 2010e). Increased productivity on the same amount of land 

allows growers to preserve habitat while maintaining food and fiber security (Cotton 

Incorporated, 2010e). Various methods for promoting animal and plant biodiversity in and 

around cotton fields have already been discussed above. Habitat preservation and plant 

biodiversity have a large impact on insect populations. Research conducted by Altieri (1999)

and Altieri and Letourneau (Altieri and Letourneau, 1982, 1984) indicates: 

1) Maintaining some weeds harbors and supports beneficial arthropods that suppress 

herbivore insect pests; 

2) Polycultures of plants support lower herbivore populations because they provide a more 

stable and continuous availability of food and habitat for beneficial insects; and 

3) Adjacent wild vegetation provides alternate food and habitat for natural enemies to pest 

herbivores. 
BAYER TWINLINKTM COTTON

25

The use of broad-spectrum insecticides is one of the most severe constraints for biological 

diversity in crops (Cattaneo et al., 2006; Sisterson et al., 2007; USDA-APHIS, 2010a). One of 

the benefits of Bt cotton has been the reduction of broad-spectrum insecticide use during cotton 

production (Fernandez-Cornejo and Caswell, 2006). 

However, there is concern over the non-target effects of transgenic cotton, especially Bt cotton, 

on beneficial insects and non-target pests. Research in Arizona has shown that Bt cotton has a 

minimum effect on both the number and function of foliar-dwelling arthropod natural enemies 

(Naranjo, 2005a, 2005b). In contrast, broad-spectrum insecticide use caused a 48% reduction in 

13 of the 22 taxa that were studied (Naranjo, 2005a). A comparison of non-transgenic and 

transgenic cotton revealed no substantial impact on ant and beetle diversity in cotton fields, but 

broad-spectrum insecticide use considerably reduced this diversity (Cattaneo et al., 2006).

Soil microorganisms play a key role in soil structure formation, decomposition of organic matter, 

toxin removal, nutrient cycling, and most biochemical soil processes (Garbeva et al., 2004). 

They also suppress soil-borne plant diseases and promote plant growth (Doran et al., 1996). The 

main factors affecting microbial population size and diversity include plant type (providers of 

specific carbon and energy sources into the soil), soil type (texture, structure, organic matter, 

aggregate stability, pH, and nutrient content), and agricultural management practices (crop 

rotation, tillage, herbicide and fertilizer application, and irrigation) (Garbeva et al., 2004). Plant 

roots, including cotton, release a large variety of compounds into the soil creating a unique 

environment for microorganisms in the rhizosphere. Microbial diversity in the rhizosphere is 

extensive and differs from the microbial community in the bulk soil (Garbeva et al., 2004). 

2.4.4 Gene Movement

The possibility of gene movement from the host plant into native or feral populations of 

Gossypium species or wild or weedy relatives of cotton has been raised as an issue of concern 

(US-EPA, 2010a). This subsection provides a basis for evaluating the weediness potential of 

cotton as well as the potential for outcrossing and gene escape in cotton. The potential for 

outcrossing or gene escape is defined as the ability of the gene to escape to wild cotton relatives. 

G. hirsutum is a perennial plant that is cultivated as an annual in the U.S. (USDA-ERS, 2009). 

Cultivation as an annual means that the entire cotton plant is harvested at the end of each 

growing year, and new seed is planted in following years. Because of the structure of the cotton 

boll, cotton seed dispersal in the field is rarely successful (Scott, 2008). Pollen dispersal is the 

most likely potential source of gene movement (Scott, 2008).

The cotton flower is perfect, containing both male and female parts, and can self- or crosspollinate (Meyer et al., 2007). However, the flowers of most cotton species, including G. 

hirsutum, are generally considered to be self-pollinating (Meyer et al., 2007; Scott, 2008).

Cotton pollen is heavy and somewhat sticky and does not lend itself to wind dispersal and 

subsequent pollination (Scott, 2008). Cotton can, however, be pollinated by insects. Bees —

wild bees, honeybees (Apis mellifera), and bumblebees (Bombus spp.) — are the primary insect 

pollinators (Pleasants and Wendel, 2010). Bees collect mainly the nectar from the cotton plants, 

and rarely the pollen. In addition, physical isolation from plants attractive to the bees 
BAYER TWINLINKTM COTTON

26

significantly reduces the potential for pollen movement, as cotton flowers have a nectar high in 

glucose and low in sucrose, which probably makes it less attractive to bees. McGregor (1976)

traced the movement of pollen from a cotton field surrounded by a large number of honeybee 

colonies using fluorescent particles on source cotton plants. McGregor illustrated a rapid decline 

in the transference of cotton pollen over distance, and found that at 150 to 200 feet away from 

the source plant, only 1.6% of the bees showed the presence of the fluorescent particles. 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, 2010c). 

Despite these characteristics of cotton pollen which limit wind dispersal and bee pollination, it is 

common practice to maintain isolation distances to prevent pollen movement from other cotton 

sources and to plant border or barrier rows to intercept pollen to maintain and protect cotton seed 

characteristics for seed certification programs (Wozniak, 2002). Field monitoring for off-types, 

other crops, weeds, disease etc. is carried out by both growers and state crop improvement 

associations (AOSCA, 2010a). Seed handling standards are established by AOSCA to reduce 

the likelihood of seed source mixing during planting, harvesting, transporting, storage, cleaning, 

and ginning (Bradford, 2006). 

A majority of field-based research with cotton shows an outcrossing rate of 10% or less within 1 

meter of the pollen source (USDA-APHIS, 2010a). In upland cotton, outcrossing studies suggest 

that pollen carryover decreases very rapidly as the distance to the closest marker pollen row 

increases, and that very little pollen is transferred beyond 12 meters (McGregor, 1976; Scott, 

2008; Vaissiere and Vinson, 1994).

Reports of outcrossing of a bromoxynil-tolerant cotton are described in the USDA petition for 

CalGene’s GlyTol cotton 06-332-01p and in a study of pollen mediated gene flow by Van 

Deynze et al. (2005). Seed samples were collected in the border rows of Calgene's winter 

nursery sites in Catamarca, Argentina, and Pongola, Republic of South Africa, as well as in 

Stoneville, MS, USA. Sampling distance was one to 20 meters away from the bromoxyniltolerant cotton. The frequency of outcrossing was determined by the crop and the pollinator. It 

is interesting to note that although the rate is higher for Argentina and South Africa (most likely 

due to the behavioral differences between European and African honeybees), the pattern of 

decline with distance was the same. Van Deynze et al. (2005) measured pollen-mediated gene 

flow (PGF) in four directions over two years from commercial seed fields of bromoxynil-tolerant 

(BXN) and Roundup Ready®

1994

(RR) cotton in the California cotton growing region at various 

distances from non-transgenic cotton fields. Their results confirmed, as well as refined, those of 

Kareiva et al. ( ), as larger distances were studied. In spite of variations due to the respective 

cardinal positions of the fields, the same decline with distance was observed. Van Deynze et al. 

further reported that a 55-meter non-planted area was a sufficiently broad distance to maintain 

varietal purity (Van Deynze et al., 2005). This finding is consistent with the distance limitations 

identified by McGregor.

There are few wild relatives of cultivated cotton where cotton is cultivated. Two species of 

cotton are cultivated in the U.S.: upland cotton (G. hirsutum ) and Pima cotton (G. barbadense )

(USDA-ERS, 2009). There are two wild relatives of interest to U.S. growers: G. thurberi and 

G. tomentosum, found in the mountains of southern Arizona and in Hawaii, respectively. 

Outcrossing of genes from TwinLinkTM Cotton to G. thurberi is unlikely to occur because G. 
BAYER TWINLINKTM COTTON

27

thurberi contains only the D genome whereas G. hirsutum contains both the A and D genome. 

The difference in chromosome numbers precludes sexual compatibility of G. hirsutum with G. 

thurberi (OECD, 2008).

G. tomentosum is native to the Hawaiian Islands, occurring primarily in arid, rock, or clay 

coastal plains (Pleasants and Wendel, 2010; USDA-APHIS, 2010a). G. tomentosum is not 

known to be weedy or to have invasive characteristics, and is considered a rare plant in Hawaii

(Pleasants and Wendel, 2010; University of Hawaii at Manoa, 2001). In laboratory and 

greenhouse breeding programs with hand pollination, G. tomentosum and G. hirsutum are 

sexually compatible and form viable progeny (Pleasants and Wendel, 2010). However, DNA 

marker analyses have not found evidence of genes from G hirsutum occurring in native 

populations of G. tomentosum (DeJoode and Wendel, 1992). It is possible that the lack of 

evidence of movement of G. hirsutum genes into G. tomentosum is the result of lack of 

opportunity because cotton has not been grown commercially in Hawaii for at least the last 45 

years (USDA-APHIS, 2010a). 

Historic literature suggests that there are barriers to cross pollination between G. tomentosum and 

either G. hirsutum or G. barbadense based on different flowering patterns and pollinators 

(Pleasants and Wendel, 2010). Field and laboratory studies demonstrated that the historic 

literature is incorrect, and that these three species share common pollinators, and further that 

differences in flower structure and flowering habits do not serve as barriers to cross pollination 

(Pleasants and Wendel, 2010). 

EPA recognizes a possibility of gene transfer from Bt cotton to feral cotton relatives in Hawaii, 

Florida, Puerto Rico, and the U.S. Virgin Islands (US-EPA, 2008a). Where feral populations of 

cotton species similar to cultivated cotton exist, EPA has prohibited the sale or distribution of Bt 

cotton in those areas, on the premise that these containment measures would prevent the 

movement of the registered Bt endotoxin from Bt cotton to wild or feral relatives (US-EPA, 

2008a). 

Feral populations of G. hirsutum have been listed as threatened and endangered by the State of 

Florida (Coile and Garland, 2003). However, in Florida, wild G. hirsutum is not present in the 

northwestern panhandle where cotton cultivation occurs (Coile and Garland, 2003; USDANASS, 2007; Wunderlin and Hansen, 2010). 

Horizontal gene transfer and consequent expression of DNA from a plant species to bacteria is 

unlikely to occur (Keese, 2008). Many bacteria (or parts thereof) that are closely associated with 

plants have been sequenced, including Agrobacterium and Rhizobium (Kaneko et al., 2000; 

Kaneko et al., 2002; Wood et al., 2001). There is no evidence that these organisms contain genes 

derived from plants. In cases where the review of sequence data implied that horizontal gene 

transfer occurred, these events were inferred to occur on an evolutionary time scale in the order 

of millions of years (Brown, 2003; Koonin et al., 2001). 

2.5 PUBLIC HEALTH

Public health concerns surrounding GE cotton, such as TwinLinkTM Cotton, focus primarily 

on human and animal consumption. Although cotton is grown primarily for textile
BAYER TWINLINKTM COTTON

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production, valuable food oil is produced from cotton seed. The remaining seed residue 

(cottonseed meal and hulls) is used as livestock feed and as a high-protein flour (OECD, 

2009). Cotton seed meal animal feed provides protein, fat, and energy (National Cottonseed 

Products Association, 2002).

Non-GE 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 human food safety prior to release in the market. Under the FFDCA, it is the 

responsibility of food manufacturers to ensure that the products they market are safe and 

properly labeled. Food derived from TwinLinkTM Cotton must be in compliance with all 

applicable legal and regulatory requirements. GE organisms for food and feed may undergo 

a voluntary consultation process with the FDA prior to release onto the market. Although a 

voluntary process, thus far, all applicants who have wished to commercialize a GE variety 

that will be included in the food supply have completed a consultation with the FDA. In a 

consultation, a developer who intends to commercialize a bioengineered food meets with the 

agency to identify and discuss relevant safety, nutritional, or other regulatory issues 

regarding the bioengineered food and then submits to FDA a summary of its scientific and 

regulatory assessment of the food. FDA evaluates the submission and responds to the 

developer by letter (US-FDA, 2010).

Bayer has provided the FDA with information on the identity, function, and characterization of 

the genes for TwinLinkTM Cotton, including expression of the gene products. The FDA is 

currently reviewing the information submitted by the applicant. In the absence of a completed 

FDA determination, APHIS takes into consideration prior FDA reviews of comparable products 

to make a preliminary assessment of the potential food and safety impacts. Note that with regard 

to the expression of glufosinate ammonium tolerance, the gene construct in the Bayer 

TwinLinkTM Cotton is the same as that approved by the FDA in June 2003 for the LibertyLink®

Cotton product (US-FDA, 2003). In that approval, the FDA noted that the transformational 

event in LibertyLink®

US-FDA, 

2003

Cotton was not materially different in composition, safety, or any other 

relevant parameter than other cotton grown, marketed and consumed at that time (

). This previous FDA review will be used by APHIS to analyze the food and safety impacts 

associated with the incorporation and expression of glufosinate ammonium tolerance in 

TwinLinkTM Cotton.

The FDA’s oversight of the food and safety impacts associated with the incorporation and 

expression of pesticidal substances, in this case, the Cry proteins associated with Bt, are more 

limited. The EPA is the primary authority for the review of plant-incorporated protectants.

EPA Section 3 FIFRA registration applications have been submitted by Bayer to the EPA for 

Cry1Ab cotton, Cry2Ae cotton and TwinLinkTM Cotton. EPA is currently reviewing information

submitted by the applicant on the efficacy and potential environmental concerns associated with 

the use of this product. APHIS has been advised that the product will need three separate new 

active ingredient registrations under Section 3 of FIFRA:

• One for Cry1Ab from event 3T04-40.

• One for Cry2Ae from event GHB119.

• One for the stacked event combining both Cry proteins.
BAYER TWINLINKTM COTTON

29

In the absence of a completed EPA determination, APHIS takes into consideration prior EPA 

reviews of comparable products to make a preliminary assessment of the potential impacts. The 

EPA, in 2008, published a Biopesticides Registration Action Document (BRAD) for Bacillus 

thuringiensis (Bt) incorporated protectants (US-EPA, 2008a). Based on a comprehensive human 

health effects assessment, the Bt BRAD found no unreasonable adverse effects associated with

exposure to the Bt products. The Bt protein is a registered microbial pesticide which is approved 

for use on food crops. The EPA concluded in the BRAD that the Bt products incorporated as 

plant protectants would be expected to behave as expected of a dietary protein (US-EPA, 2008a). 

A tolerance exemption is in place for Cry1Ab protein in all crops (40 CFR §174.511; US-EPA, 

2010d), as well as for the PAT protein (40 CFR §174.522; US-EPA, 2010g). A temporary 

exemption from the requirement of a tolerance has been issued for Cry2Ae (40 CFR §174.530; 

US-EPA, 2010e). This previous EPA review will be used by APHIS to analyze the food and 

safety impacts associated with the incorporation and expression of Cry proteins in TwinLinkTM 

Cotton.

Glufosinate ammonium is currently registered under various trade names for control of weeds in 

cotton and other crops; the Ignite®/Liberty® trade name is registered for use on LibertyLink®

corn, cotton, soy, rice and canola varieties (BCS, 2010a; Scott, 2008). EPA’s core pesticide risk 

assessment and regulatory processes ensure that protections are in place for all populations of 

nontarget species. These assessments provide EPA with information needed to develop label use 

restrictions for the pesticide. Growers are required to use pesticides, such as glufosinate 

ammonium, consistent with the application instructions provided on the EPA-approved pesticide 

label (see, e.g., BCS, 2010a). These label restrictions carry the weight of law and are enforced 

by EPA and the states (Federal Insecticide, Fungicide, and Rodenticide Act 7 USC 136j 

(a)(2)(G) Unlawful Acts). Therefore, it is expected that glufosinate ammonium use on the 

TwinLinkTM Cotton product would be consistent with the EPA-approved label.

Glufosinate ammonium acts in plants by inhibiting the enzyme glutamine synthase causing a 

toxic buildup of ammonia within the treated plant (Scott, 2008). Glufosinate ammonium is a 

nonselective herbicide for both non-crop and crop uses. It is highly biodegradable, has no 

residual activity, and has very low toxicity for humans. Glufosinate ammonium degrades rapidly 

in microbially active soils and also readily binds to soil particles, and its short-lived metabolites 

have not been found to accumulate in the environment. Soil microorganisms, bees, earthworms, 

birds, and mammals are unaffected by glufosinate ammonium (Scott, 2008). A food tolerance 

for residues of glufosinate ammonium has been published (40 CFR §180.473; US-EPA, 2010c).

2.6 ANIMAL FEED

As noted in the discussion of Public Health (Subsection 2.5), 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 (National Cottonseed Products Association, 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). 
BAYER TWINLINKTM COTTON

30

Cottonseed meal is usually sold as a high protein animal feed supplement, providing as much as 

41% protein by weight (National Cottonseed Products Association, 2002). The meal can be 

used alone or in combination with other plant and animal protein sources (National Cottonseed 

Products Association, 2002). Cottonseed hulls are the outer covering of the cotton seed which 

are removed prior to oil extraction (National Cottonseed Products Association, 2002). The 

hulls provide a source of fiber to animal feed rations (National Cottonseed Products 

Association, 2002). Whole cottonseed is the seed remaining after the long fibers have been 

removed (National Cottonseed Products Association, 2002). The whole cotton seed contains a 

small quantity of attached linters, and as animal feed provides protein, energy and fiber 

(National Cottonseed Products Association, 2002).

Although cottonseed meal is a widely used animal feed (Blasi and Drouillard, 2002; Calhoun, 

2011), gossypol, one of the chemical constituents of cottonseed meal, is potentially toxic 

(Gadberry, 2011). Ruminants (i.e. cattle) have the ability to detoxify gossypol during the 

fermentation process in the gut (Gadberry, 2011). Gossypol has been identified as potentially 

causing reduced fertility in young developing bulls, resulting in recommendations to limit 

cottonseed meal in the diet for developing bulls (Blasi and Drouillard, 2002; University of 

Arkansas Cooperative Extension Service, 2011). 

Non-GE 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 animal feed safety prior to release in the market. Under the FFDCA, it is the 

responsibility of food and feed manufacturers to ensure that the products they market are 

safe and properly labeled. Feed derived from TwinLinkTM Cotton must be in compliance 

with all applicable legal and regulatory requirements. GE organisms for feed may undergo a 

voluntary consultation process with the FDA prior to release onto the market. Although a 

voluntary process, thus far, all applicants who have wished to commercialize a GE variety 

that will be included in the food supply have completed a consultation with the FDA. In a 

consultation, a developer who intends to commercialize a bioengineered food meets with the 

agency to identify and discuss relevant safety, nutritional, or other regulatory issues 

regarding the bioengineered food and then submits to FDA a summary of its scientific and 

regulatory assessment of the food. FDA evaluates the submission and responds to the 

developer by letter (US-FDA, 2010).

Bayer has provided the FDA with information on the identity, function, and characterization of 

the genes for TwinLinkTM Cotton, including expression of the gene products. The FDA is 

currently reviewing the information submitted by the applicant. In the absence of a completed 

FDA determination, APHIS takes into consideration prior FDA reviews of comparable products 

to make a preliminary assessment of the potential food and safety impacts. Note that with regard 

to the expression of glufosinate ammonium tolerance, the gene construct in the Bayer 

TwinLinkTM Cotton is the same as that approved by the FDA in June 2003 for the LibertyLink®

Cotton product (US-FDA, 2003). In that approval, the FDA noted that the transformational 

event in LibertyLink®

US-FDA, 

2003

Cotton was not materially different in composition, safety, or any other 

relevant parameter than other cotton grown, marketed and consumed at that time (

). This previous FDA review will be used by APHIS to analyze the food and safety impacts 

associated with the incorporation and expression of glufosinate ammonium tolerance in 

TwinLinkTM Cotton.
BAYER TWINLINKTM COTTON

31

The FDA’s oversight of the food and safety impacts associated with the incorporation and 

expression of pesticidal substances, in this case, the Cry proteins associated with Bt, are more 

limited. The EPA is the primary authority for the review of plant-incorporated protectants.

EPA Section 3 FIFRA registration applications have been submitted by Bayer to the EPA for 

Cry1Ab cotton, Cry2Ae cotton and TwinLinkTM Cotton. EPA is currently reviewing information

submitted by the applicant on the efficacy and potential environmental concerns associated with 

the use of this product. APHIS has been advised that the product will need three separate new 

active ingredient registrations under Section 3 of FIFRA:

• One for Cry1Ab from event 3T04-40.

• One for Cry2Ae from event GHB119.

• One for the stacked event combining both Cry proteins.

In the absence of a completed EPA determination, APHIS takes into consideration prior EPA 

reviews of comparable products to make a preliminary assessment of the potential impacts. The 

EPA, in 2008, published a Biopesticides Registration Action Document (BRAD) for Bacillus 

thuringiensis (Bt) incorporated protectants (US-EPA, 2008a). Based on a comprehensive human 

health effects assessment, the Bt BRAD found no unreasonable adverse effects associated with

exposure to the Bt products. The Bt protein is a registered microbial pesticide which is approved 

for use on food crops. The EPA concluded in the BRAD that the Bt products incorporated as 

plant protectants would be expected to behave as expected of a dietary protein (US-EPA, 2008a). 

A tolerance exemption is in place for Cry1Ab protein in all crops (40 CFR §174.511; US-EPA, 

2010d), as well as for the PAT protein (40 CFR §174.522; US-EPA, 2010g). A temporary 

exemption from the requirement of a tolerance has been issued for Cry2Ae (40 CFR §174.530; 

US-EPA, 2010e). This previous EPA review will be used by APHIS to analyze the food and 

safety impacts associated with the incorporation and expression of Cry proteins in TwinLinkTM 

Cotton.

Glufosinate ammonium is currently registered under various trade names for control of weeds in 

cotton and other crops; the Ignite®/Liberty® trade name is registered for use on LibertyLink®

corn, cotton, soy, rice and canola varieties (BCS, 2010a; Scott, 2008). EPA’s core pesticide risk 

assessment and regulatory processes ensure that protections are in place for all populations of 

nontarget species. These assessments provide EPA with information needed to develop label use 

restrictions for the pesticide. Growers are required to use pesticides, such as glufosinate 

ammonium, consistent with the application instructions provided on the EPA-approved pesticide 

label (see, e.g., BCS, 2010a). These label restrictions carry the weight of law and are enforced 

by EPA and the states (Federal Insecticide, Fungicide, and Rodenticide Act 7 USC 136j 

(a)(2)(G) Unlawful Acts). Therefore, it is expected that glufosinate ammonium use on the 

TwinLinkTM Cotton product would be consistent with the EPA-approved label.

Glufosinate ammonium acts in plants by inhibiting the enzyme glutamine synthase causing a 

toxic buildup of ammonia within the treated plant (Scott, 2008). Glufosinate ammonium is a 

nonselective herbicide for both non-crop and crop uses. It is highly biodegradable, has no 

residual activity, and has very low toxicity for humans. Glufosinate ammonium degrades rapidly 

in microbially active soils and also readily binds to soil particles, and its short-lived metabolites 
BAYER TWINLINKTM COTTON

32

have not been found to accumulate in the environment. Soil microorganisms, bees, earthworms, 

birds, and mammals are unaffected by glufosinate ammonium (Scott, 2008). A food tolerance 

for residues of glufosinate ammonium has been published (40 CFR §180.473; US-EPA, 2010c).

2.7 SOCIOECONOMIC ISSUES

Cotton has been cultivated for fiber for over 5,000 years (OECD, 2008). Cotton is grown 

primarily for its lint fibers which are made into textiles (OECD, 2009). Cotton seed also 

produces valuable food oil and the remaining seed residue (cottonseed meal and hulls) is 

used as livestock feed and as a high-protein flour (OECD, 2009). The remainder of the 

plant is left in the field for decomposition as fertilizer (OECD, 2009).

In the U.S. for the 2010 production year, cotton was grown on 4.4 million hectares (10.9 million 

acres (USDA-NASS, 2010b). Cotton is produced in the Cotton Belt, 17 southern states, from 

Virginia to California (Meyer et al., 2007; USDA-NASS, 2010c). The major cotton producing 

states are Texas (5.4 million acres), Georgia (1.3 million acres), Arkansas (0.540 million acres), 

Mississippi (0.420 million acres), North Carolina (0.545 million acres) and Tennessee (0.387 

million acres) (USDA-NASS, 2010c). Texas, Arkansas, Georgia, North Carolina, and 

Mississippi collectively produced over 58% of the cotton in 2010 (USDA-NASS, 2010e). In 

2007, total cotton cultivated land in the U.S. was about 10,500,000 acres (slightly larger than the 

combined size of the states of Maryland and Connecticut) with a market value of about $5 billion 

(USDA-NASS, 2007). 

Cotton acreage in the U.S. rose slightly during the first half of the 2000s, with a corresponding 

increase in production (USDA-ERS, 2009). The increase in production has been attributed to 

advances in technology (seed varieties, fertilizers, pesticides, and machinery) and production 

practices (reduced tillage, irrigation, crop rotations, and pest management systems) (USDA-ERS, 

2009). The impact of these changes has been particularly evident, with yields and production 

reaching new highs (USDA-ERS, 2009). Since 2006, however, U.S. cotton planted area has 

been considerably lower, as relative prices have favored the planting of alternative crops, such as 

corn and soybeans (USDA-ERS, 2009). All regions of the Cotton Belt have experienced 

significant declines compared with the first half of the 2000s (USDA-ERS, 2009). Although 

U.S. cotton production decreased considerably following the area reductions of the late 2000s, 

consistently higher yields helped limit the effect of these acreage declines (USDA-ERS, 2009).

According to the Census of Agriculture, U.S. cotton farms numbered 18,605 in 2007, down from 

24,805 in 2002 (USDA-ERS, 2009). Although the number has fallen, cotton acreage per farm 

has risen, averaging 564 acres per farm in 2007 compared with 502 acres in 2002. The 

percentage of large cotton farms (over 1,000 acres) has continued to increase, but the share of 

small cotton farms (under 100 acres) has declined (USDA-ERS, 2009). 

The U.S. cotton industry generates about 200,000 jobs among the various sectors from farm to 

textile mill, and accounts for more than $25 billion in products and services annually (USDAERS, 2009).

Total 2010 cotton production is forecast at 18.9 million 480-pound bales, up 55% from 2009 

production of 12.2 million bales (USDA-NASS, 2010e). Yield is expected to average 841 
BAYER TWINLINKTM COTTON

33

pounds per harvested acre, up 64 pounds from 2009 (USDA-NASS, 2010e). Upland cotton 

production is forecast at 18.4 million 480-pound bales, and 56% above 2009 (USDA-NASS, 

2010e). American Pima production is forecast at 497,800 bales (USDA-NASS, 2010e).

Trade is particularly important for cotton. About 30% of the world's consumption of cotton fiber 

crosses international borders before processing, a larger share than for wheat, corn, soybeans, or 

rice (USDA-ERS, 2009). 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 

(USDA-ERS, 2009). 

Consumption of cotton by U.S. textile mills peaked in 1997; since then, U.S. mill use of cotton 

has plummeted, dropping about 50% by 2005 and nearly 70% by 2009 (USDA-ERS, 2009). 

Although the end of the Multifibre Arrangement's (MFA in 2005 was a factor, much of the 

decline in U.S. textile production occurred before then. The MFA was a multilateral agreement 

signed in 1974, but it began in the 1930s as a mechanism to protect domestic textile markets, 

establishing strict limits on imports from Japan, Hong Kong, Pakistan and India, among many 

others (Meyer et al., 2007). Under the MFA, Canada, the U.S., and the EU could set limits on 

the amount of foreign-made apparel and textiles they would allow into their countries (Meyer et 

al., 2007). The MFA ended after the 1995 Uruguay Round Agreements on trade liberalization 

(Meyer et al., 2007). The result of this change is 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, 2006). The changes after the end of the MFA is reflected in the 

importance of exports for cotton growers. The USDA ERS reports that U.S. cotton mills 

consumed 60% of the domestic cotton through the 1990s, but not long after the ending of the 

MFA quotas, 70% of the U.S. cotton 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 well-being of downstream manufacturing industries, as well as the economic wellbeing of the final consumer (USDA-ERS, 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). 

The introduction of cotton providing insect resistance or herbicide tolerance also has global 

implications. Herbicide-tolerant cotton is one of the most widely and rapidly adopted crops in 

the U.S., followed by insect-resistant cotton (USDA-ERS, 2010a). In 2010, GE varieties of 

cotton were cultivated on 93% of the acreage in the U.S., with herbicide-tolerant cotton 

cultivated on 78% of the acreage, and Bt cotton cultivated on 73% of the acreage (USDA-ERS, 

2010a).

Outside the U.S., Bt cotton has been widely adopted in India and China, two major cotton 

producers (Meyer et al., 2007). The cost savings of Bt cotton brought millions of hectares back

into cotton production in eastern China, and has also helped India’s cotton area rebound by more 

than 1 million hectares (Meyer et al., 2007). Bt cotton has also been adopted in smaller 

producing countries like Australia, Argentina, Mexico, and South Africa (Meyer et al., 2007).
BAYER TWINLINKTM COTTON

34

3 ALTERNATIVES

This document analyzes the potential environmental consequences of a determination of

nonregulated status of BCS TwinLinkTM Cotton. To respond favorably to a petition for 

nonregulated status, APHIS must determine that TwinLinkTM Cotton is unlikely to pose a plant 

pest risk. Based on its Plant Pest Risk Assessment (USDA-APHIS, 2010b) APHIS has 

concluded that TwinLinkTM Cotton is unlikely to pose a plant pest risk. Therefore, APHIS must 

determine that COT67B cotton is no longer subject to 7 CFR part 340 or the plant pest 

provisions of the Plant Protection Act. 

Two alternatives will be evaluated in this EA: 1) no action; and 2) determination of 

nonregulated status of TwinLinkTM Cotton . APHIS has assessed the potential for environmental 

impacts for each alternative in Section 4 of this EA, Environmental Consequences. 

3.1 NO ACTION: CONTINUATION AS A REGULATED ARTICLE

Under the No Action Alternative, APHIS would deny the petition. TwinLinkTM Cotton and 

progeny derived from TwinLinkTM Cotton would continue to be regulated articles under the 

regulations at 7 CFR Part 340. Permits issued or notifications acknowledged by APHIS would 

still be required for introductions of TwinLinkTM Cotton and measures to ensure physical and 

reproductive confinement would continue to be implemented. APHIS might choose this 

alternative if there were insufficient evidence to demonstrate the lack of plant pest risk from the 

unconfined cultivation of TwinLinkTM Cotton. 

This alternative is not the Preferred Alternative because APHIS has concluded through a Plant 

Pest Risk Assessment (USDA-APHIS, 2010b) that TwinLinkTM Cotton is unlikely to pose a 

plant pest risk. 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. 

3.2 PREFERRED ALTERNATIVE: DETERMINATION THAT TWINLINKTM 

COTTON IS NO LONGER A REGULATED ARTICLE

Under this alternative, TwinLinkTM Cotton and progeny derived from them would no longer be 

regulated articles under the regulations at 7 CFR Part 340. TwinLinkTM Cotton is unlikely to 

pose a plant pest risk (USDA-APHIS, 2010b). Permits issued or notifications acknowledged by 

APHIS would no longer be required for introductions of TwinLinkTM Cotton and progeny 

derived from this event. This alternative best meets the agency’s purpose and need to respond 

appropriately to a petition for nonregulated status based on the requirements in 7 CFR part 340 

and the agency’s authority under the plant pest provisions of the Plant Protection Act. Because

the agency has concluded that TwinLinkTM Cotton is unlikely to pose a plant pest risk, a 

determination of nonregulated status of TwinLinkTM Cotton is a response that is consistent with 

the plant pest provisions of the PPA, the regulations codified in 7 CFR part 340, and the 

biotechnology regulatory policies in the Coordinated Framework.

Under this alternative, growers may have future access to TwinLinkTM Cotton and progeny 

derived from this event if the developer decides to commercialize TwinLinkTM Cotton. 
BAYER TWINLINKTM COTTON

35

3.3 ALTERNATIVES CONSIDERED BUT REJECTED FROM FURTHER 

CONSIDERATION 

APHIS assembled a list of alternatives that might be considered for TwinLinkTM Cotton. The 

agency evaluated these alternatives, in light of the agency's authority under the plant pest 

provisions of the Plant Protection Act, and the regulations at 7 CFR part 340, with respect to 

environmental safety, efficacy, and practicality to identify which alternatives would be further 

considered for TwinLinkTM Cotton. Based on this evaluation, APHIS rejected several 

alternatives. These alternatives are discussed briefly below along with the specific reasons for 

rejecting each.

3.3.1 Prohibit Any TwinLinkTM Cotton from Being Released

In response to public comments that stated a preference that no GE organisms enter the 

marketplace, APHIS considered prohibiting the release of TwinLinkTM Cotton, including 

denying any permits associated with the field testing. APHIS determined that this alternative is 

not appropriate given that APHIS has concluded that TwinLinkTM Cotton is unlikely to pose a 

plant pest risk (USDA-APHIS, 2010b). 

In enacting the Plant Protection Act, Congress found that 

[D]ecisions affecting imports, exports, and interstate movement of products regulated 

under [the Plant Protection Act] shall be based on sound science... § 402(4).

On March 11, 2011, in a Memorandum for the Heads of Executive Departments and Agencies, 

the White House Emerging Technologies Interagency Policy Coordination Committee developed 

broad principles, consistent with Executive Order 13563, to guide the development and 

implementation of policies for oversight of emerging technologies (such as genetic engineering) 

at the agency level. In accordance with this memorandum, agencies should adhere to Executive 

Order 13563 and, consistent with that Executive Order, the following principle, among others, to 

the extent permitted by law, when regulating emerging technologies: 

“[D]ecisions should be based on the best reasonably obtainable scientific, technical, 

economic, and other information, within the boundaries of the authorities and mandates 

of each agency” 

Based on our Plant Pest Risk Assessment (USDA-APHIS, 2010b) and the scientific data 

evaluated therein, APHIS has concluded that TwinLinkTM Cotton is unlikely to pose a plant 

pest risk. Accordingly, there is no basis in science for prohibiting the release of TwinLinkTM 

Cotton.

3.3.2 Approve the petition in part

The regulations at 7 CFR 340.6(d)(3)(i) state that APHIS may "approve the petition in whole 

or in part." For example, a determination of nonregulated status in part may be appropriate if 

there is a plant pest risk associated with some, but not all lines described in a petition. 

Because APHIS has concluded that TwinLinkTM Cotton is unlikely to pose a plant pest risk, 
BAYER TWINLINKTM COTTON

36

there is no regulatory basis under the plant pest provisions of the Plant Protection Act for 

considering approval of the petition only in part. 

3.3.3 Isolation distance between TwinLinkTM Cotton and non-GE cotton and geographical 

restrictions

In response to public concerns of gene movement between GE and non-GE plants, APHIS 

considered requiring an isolation distance separating TwinLinkTM Cotton from non-GE cotton 

production. However, because APHIS has concluded that TwinLinkTM Cotton is unlikely to 

pose a plant pest risk (USDA-APHIS, 2010b), an alternative based on requiring isolation 

distances would be inconsistent with the statutory authority under the plant pest provisions of the 

Plant Protection Act and regulations in 7 CFR part 340.

APHIS also considered geographically restricting the production of TwinLinkTM Cotton based on 

the location of production of non-GE cotton in organic production systems in response to public 

concerns regarding possible gene movement between GE and non-GE plants. However, as 

presented in APHIS’ plant pest risk assessment for TwinLinkTM Cotton, there are no geographic 

differences associated with any identifiable plant pest risks for TwinLinkTM Cotton (USDAAPHIS, 2010b). This alternative was rejected and not analyzed in detail because APHIS has 

concluded that TwinLinkTM Cotton does not pose a plant pest risk, and will not exhibit a greater 

plant pest risk in any geographically restricted area. Therefore, such an alternative would not be 

consistent with APHIS’ statutory authority under the plant pest provisions of the Plant Protection 

Act and regulations in Part 340 and the biotechnology regulatory policies embodied in the 

Coordinated Framework. 

Based on the foregoing, the imposition of isolation distances or geographic restrictions would 

not meet APHIS’ purpose and need to respond appropriately to a petition for nonregulated 

status based on the requirements in 7 CFR part 340 and the agency’s authority under the plant 

pest provisions of the Plant Protection Act. Nevertheless, APHIS is not expecting significant 

effects. However, individuals might choose on their own to geographically isolate their nonGE cotton productions systems from TwinLinkTM Cotton or to use isolation distances and 

other management practices to minimize gene movement between cotton fields. 

3.3.4 Requirement of Testing For TwinLinkTM Cotton

During the comment periods for other petitions for nonregulated status, some commenters 

requested USDA to require and provide testing to identify GE products in non-GE production 

systems. APHIS notes 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 TwinLinkTM Cotton does not pose a 

plant pest risk (USDA-APHIS, 2010b), the imposition of any type of testing requirements is 

inconsistent with the plant pest provisions of the Plant Protection Act, the regulations at 7 CFR 

part 340 and the biotechnology regulatory policies embodied in the Coordinated Framework. 

Therefore, imposing such a requirement for TwinLinkTM Cotton would not meet APHIS’ 

purpose and need to respond appropriately to the petition in accordance with its regulatory 

authorities.
BAYER TWINLINKTM COTTON

37

3.4 COMPARISON OF ALTERNATIVES 

Table 3-1 presents a summary of the potential impacts associated with selection of either of the 

alternatives evaluated in this EA. The impact assessment is presented in Section 4 of this EA.

Table 3-1: Summary of Potential Impacts and Consequences of Alternatives

Attribute/Measure Alternative A: No Action

Alternative B:

Determination of 

Nonregulated Status

Meets Purpose and Need and Objectives No Yes

Unlikely to pose a plant pest risk Satisfied through use of 

regulated field trials

Satisfied – risk assessment 

(USDA-APHIS, 2010b)

Management Practices

Acreage and Areas of Cotton Production Unchanged Unchanged

Cropping Practices Unchanged Unchanged

Seed Production Unchanged Unchanged

Organic Farming Unchanged Unchanged

Specialty Cotton Production Unchanged Unchanged

Physical Environment

Water Resources Unchanged Unchanged

Soil Unchanged Unchanged

Air Quality Unchanged Unchanged

Climate Change Unchanged Unchanged

Animal and Plant Communication

Animals Unchanged Unchanged

Plants Unchanged Minimal

Biological Diversity Unchanged Minimal

Gene Movement Unchanged Unchanged

Public Health

Human Health Unchanged Unchanged

Worker Safety Unchanged Unchanged 

Animal Feed Unchanged Unchanged

Socioeconomic Issues

Domestic Economic Environment Unchanged Unchanged

Trade Economic Environment Unchanged Unchanged

Social Environment Unchanged Unchanged

Other Cumulative Effects Unchanged Unchanged

Threatened and Endangered Species Unchanged Unchanged 

Other U.S Regulatory Approvals Unchanged for existing 

deregulated GE organisms

FDA consultation pending, 

EPA tolerance exemptions 

and conditional pesticide 

registrations being reviewed

Compliance with Other Laws

CWW, CAA, EOs Fully compliant Fully compliant
BAYER TWINLINKTM COTTON

38

Notes:

1. Unchanged – the current conditions will not change as a result of the selection of this alternative.

2. Minimal – the current conditions may change slightly as a result of the selection of this alternative, but the 

changes, if any, are not deemed significant.
BAYER TWINLINKTM COTTON

39

4 ENVIRONMENTAL CONSEQUENCES

This analysis of potential environmental consequences addresses the potential impact to the 

human environment from the alternatives analyzed in this EA, namely taking no action and a 

determination by the agency that TwinLinkTM Cotton does not pose a plant pest risk. 

4.1 SCOPE OF THE ENVIRONMENTAL ANALYSIS

Potential 

environmental impacts from the No Action Alternative and the Preferred Alternative for 

TwinLinkTM Cotton are described in detail throughout this section. A cumulative effects analysis 

is also included for each environmental issue and includes a discussion of the cumulative impacts

that are associated with the Preferred Alternative, when combined with other recent past, present 

and reasonably foreseeable future actions within the affected environment. Certain aspects of 

this product and its cultivation would be no different between the alternatives; those instances 

are described below. 

For the discussion of environmental consequences, this section addresses the following 

principal areas of potential environmental concern:

• Agricultural Production of Cotton (Subsection 4.2);

• Physical Environment (Subsection 4.3);

• Animal and Plant Communities (Subsection 4.4);

• Public Health (Subsection 4.5); 

• Animal Feed (Subsection 4.6);

• Socioeconomic Issues (Subsection 4.7); 

• Other Cumulative Effects (Subsection 4.8);

• Threatened and Endangered Species (Subsection 4.9); and

• Consideration of Executive Orders, Standards, and Treaties Relating to Environmental 

Impacts (Subsection 4.10).

Although the Preferred Alternative would allow for new plantings of TwinLinkTM Cotton to 

occur anywhere in the U.S., APHIS is limiting the environmental analysis to those areas that 

currently support cotton production, as identified by the National Agricultural Statistics Service 

(NASS) 2007 Census of Agriculture. The NASS found that cotton is currently produced in the 

following 17 states: Alabama, Arizona, Arkansas, California, Florida, Georgia, Kansas, 

Louisiana, Mississippi, Missouri, New Mexico, North Carolina, Oklahoma, South Carolina, 

Tennessee, Texas, and Virginia (USDA-NASS, 2010c). 

The environmental consequences of the No Action and Preferred Alternatives are analyzed under 

the assumption that farmers who produce conventional cotton, TwinLinkTM Cotton, or cotton 

using organic methods are using reasonable, commonly accepted best management practices 

specific to their agricultural cotton production. However, APHIS recognizes that not all farmers 

follow these best management practices for cotton. Thus, the analyses of the environmental 

effects will also include the assumption that some farmers do not follow these best management 

practices.
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4.2 AGRICULTURAL PRODUCTION OF COTTON 

One of APHIS’s missions is to improve American agricultural productivity. Best management 

practices are commonly accepted, practical ways to grow cotton, regardless of whether the cotton 

farmer is using conventional practices with non-GE or GE varieties, or organic practices. These 

management practices consider crop-specific planting dates, seeding rates, and harvest times, 

among others. Over the years, cotton production has resulted in well-established, widelypracticed management practices that are available through local Cooperative Extension Service 

offices and their respective websites. The National Information System for the Regional 

Integrated Pest Management Centers publishes crop profiles for major crops on a state-by-state 

basis. These crop profiles provide production guidance for local growers, including 

recommended practices for specific pest control. Crop profiles for many of the cotton 

production states can be reviewed at (www.ipmcenters.org/cropprofiles/index.cfm). 

BCS’ studies demonstrate that agronomic characteristics and cultivation practices required for 

TwinLinkTM Cotton are essentially indistinguishable from other cotton varieties, including other 

herbicide-tolerant and insect-resistant varieties (Scott, 2008; USDA-APHIS, 2010b). Although 

TwinLinkTM Cotton might be expected to replace other varieties of cotton currently cultivated, 

new acreage is not expected to be developed to accommodate the cultivation of TwinLinkTM 

Cotton (Scott, 2008). None of the best management practices currently employed for cotton 

production is expected to change if TwinLinkTM Cotton is deregulated. Accordingly, the 

potential impacts on agricultural production of TwinLinkTM Cotton resulting from management 

practices associated with the No Action and Preferred Alternatives are the same.

4.2.1 Acreage and Areas of Cotton Production

GE and non-GE cotton varieties are continually under development. Cotton acreage averaged 

over 14.5 million acres during the first half of the 2000s (USDA-APHIS, 2010a). Since 2006, 

however, U.S. cotton planted acreage has been considerably lower as market prices have favored 

the planting of alternative crops, such as corn and soybeans (USDA-APHIS, 2010a). Most of the 

U.S. cotton acreage is planted in GE cotton. Of the 11.3 million acres planted in cotton in 2010,

93% (10.5 million acres) were GE cotton. Of this, 73% of the GE cotton acreage was GE insectresistant (Bt) cotton and 78% was herbicide-tolerant (USDA-ERS, 2010a, 2010c). Most cotton 

is planted on farms that have been in cotton production for at least five years (USDA-NASS, 

2007). 

Based on current acreage trends, conventional cotton production practices with GE varieties will 

likely continue to dominate or perhaps increase in acreage under the No Action Alternative. 

Cotton is currently produced commercially in 17 states (

No Action: Acreage and Areas of Cotton Production 

USDA-NASS, 2010c) and under the No 

Action Alternative, this range of production is not expected to change.

BCS’ studies demonstrate that agronomic characteristics and cultivation practices required for 

TwinLinkTM Cotton are essentially indistinguishable from other cotton varieties, including other 

herbicide-tolerant and insect-resistant varieties (

Preferred Alternative: Acreage and Areas of Cotton Production 

Scott, 2008; USDA-APHIS, 2010b). BCS posits 
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that although TwinLinkTM Cotton might be expected to replace other varieties of cotton currently 

cultivated, new acreage is not expected to be developed to accommodate the cultivation of 

TwinLinkTM Cotton (Scott, 2008). The introduced lepidopteran resistance trait and the herbicide 

tolerance trait do not confer any competitive advantage in terms of weediness or to extend the 

range of cultivation outside of existing cultivation areas (Scott, 2008). The Preferred 

Alternative, a determination of nonregulated status of TwinLinkTM Cotton, is thus not expected 

to increase cotton production, either by its availability alone or accompanied by other factors, or 

cause an increase in overall GE cotton acreage. Impacts would be similar to the No Action 

Alternative. 

Cumulative effects of a determination of nonregulated status of TwinLinkTM Cotton are unlikely. 

Neither the No Action Alternative nor a determination of nonregulated status of TwinLinkTM 

Cotton is expected to directly cause an increase in agricultural acreage devoted to cotton 

production or those cotton acres devoted to GE cotton cultivation. The availability of 

TwinLinkTM Cotton will not change cultivation areas for cotton production in the U.S. and there 

are no anticipated changes to the availability of GE and non-GE cotton varieties on the market 

under either alternative. 

Cumulative Effects: Acreage and Areas of Cotton Production 

4.2.2 Cropping Practices: Crop Rotation and Pesticide Use

Crop rotation in cotton is conducted to optimize soil nutrition and fertility, reduce pathogen 

loads, and control certain cotton pests (Gazaway et al., 2007); (University of California IPM 

Online, 2008a). Crop rotation practices have been described previously in Section 2. Crop 

rotation practices are not expected to change with the planting and production of TwinLinkTM

Cotton.

In the U.S., the cotton industry has consistently relied heavily on insecticide use strategies to 

manage arthropod pests (Gianessi and Carpenter, 1999). Insecticides were applied to 66% of the 

cotton acreage in 2007 (USDA-NASS, 2008). Of thirty listed insecticides, Acephate was the 

most utilized insecticide, with 26% of the planted acreage being treated at an average rate of 

0.900 pounds per acre per crop year (USDA-NASS, 2008). Dicrotophos was the second most 

commonly utilized insecticide, applied to 21% of the acreage at an average rate of 0.565 pounds 

per year (USDA-NASS, 2008). Other insecticides applied in the 2007 growing year included 

Acetamiprid (6% of acreage), Cyfluthrin (8% of acreage), Cypermethrin (7% of acreage), 

Imadacloprid (6% of acreage), Lambda-cyhalothrin (5% of acreage), Malathion (5% of acreage), 

and Thiamethoxam (11% of acreage). 

Resistance to commonly used insecticides (pyrethroids, organophosphates, and carbamates) has 

led to a need for new insecticide chemistries or other novel approaches such as the use of sterile 

insects, pathogens, and transgenic cotton (Gianessi and Carpenter, 1999). Cotton varieties 

expressing the Bt endotoxin have emerged as a viable product replacing many of these 

commonly used pesticides (Scott, 2008).

One of the documented benefits of Bt cotton has been the reduction in the use of broad-spectrum 

insecticides during cotton production (Benbrook, 2009; Fernandez-Cornejo and Caswell, 2006). 
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Each acre planted in Bt cotton is presumed to displace the average pounds of insecticide 

previously sprayed on an acre of conventional cotton for lepidopteran control (Benbrook, 2009). 

In a comprehensive evaluation of 13 years of USDA NASS data (1996 through 2008) on 

pesticide usage (including both herbicides and insecticides), Benbrook found that pesticide 

application rates for managing lepidopteran pests in cotton changed in direct proportion to the

adoption of Bt Cotton. Table 4-1 provides an excerpt from Benbrook’s summary of insecticide 

use.

Table 4-1: Summary of Insecticide Use for Lepidopteran Control in 

Cotton Compared with Adoption of Bt Cotton*

Cotton Crop Type

% Acreage by Year

1996 2001 2005 2008

Planted with Bt Cotton 12% 41% 60% 73%

Treated with Insecticides 48% 31% 30% 25%

*Benbrook’s study reports all 13 years of data. This table presents an extracted summary to show use trends. 

Source: Benbrook (2009) Supplemental Table 12. Insecticides Applied to Control the Budworm/Bollworm Complex 

of Insects on Conventional Varieties of Cotton, 1996 – 2008.

Benbrook’s assessment presents strong evidence that there has been a dramatic reduction in the 

use of insecticides to control lepidopteran pests in cotton directly associated with the adoption of 

Bt cotton. 

Cotton cultivation also requires substantial use of herbicides for weed control during the growing 

season and for chemical defoliation prior to harvest (Scott, 2008). In 2007, 35 different 

herbicides were applied to 97% of the cotton acreage (USDA-NASS, 2008). Glyphosate 

isopropylamine salt was the most commonly applied herbicide, applied to 85% of the planted 

acres at a rate of 1.900 pounds per acre per crop year (USDA-NASS, 2008). The next two most 

commonly applied herbicides on a per acre basis were Trifluralin and Diuron, at 29 and 26%

with average application rates of 0.921 and 0.499 pounds per acre per crop year, respectively

(USDA-NASS, 2008). Other herbicides applied to cotton included 2,4-D (6% of the acreage), 

Carfentrazone-ethyl (10% of the acreage), Flumioxazin (6% of the acreage), Pendimethalin (17% 

of the acreage), Prometryn (7% of the acreage), Pyraflufen-ethyl (8% of the acreage), 

pyrithiobac-sodium (10% of the acreage), and S-metolachlor (6% of the acreage) (USDA-NASS, 

2008). 

The consequences of adoption of herbicide tolerance show a contrasting trend. Herbicidetolerant cotton was first grown commercially in the U.S. in 1997 and by 2008, herbicide-tolerant 

cotton was planted on 68% of total cotton plantings (Brookes and Barfoot, 2010). Stacked 

varieties, providing both herbicide tolerance and insect resistance, comprised nearly 93% of the 

total plantings in 2008 (Benbrook, 2009). Benbrook has reported that the adoption of herbicidetolerant crops has resulted in an increase in the volume of herbicides applied to crops (Benbrook, 

2009). Benbrook notes that herbicide use declined between 1996 and 2001, apparently in direct 

response to the adoption of herbicide-tolerant cotton (Benbrook, 2009). However, since that 

time, herbicide use has increased. Reported increases in herbicide use reflect an increase in use 

of conventional herbicides, as well as an increase in glyphosate applications (Benbrook, 2009). 

Benbrook concludes that this reported increase in herbicide use is a direct consequence of the 
BAYER TWINLINKTM COTTON

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development of glyphosate-resistant weeds in cotton. As of 2008, nine weeds were identified as 

glyphosate-resistant, with three of these weeds, horseweed (marestail), Johnsongrass, and 

pigweed (Palmer amaranth) specifically identified as difficult to control weeds in cotton.

Under the No Action Alternative, cotton crop rotation practices and pesticide use is expected to 

remain as practiced today by the farming community. Growers will continue to have access to 

existing deregulated GE lepidopteran-resistant and herbicide-tolerant cotton varieties, as well as 

conventional cotton varieties. It is likely that growers would continue to experience the 

continued emergence of glyphosate-tolerant weeds, requiring modifications of crop management 

practices to address these weeds. These changes may involve all of the techniques identified by 

Benbrook (

No Action: Cropping Practices: Crop Rotation and Pesticide Use

2009), including use of other herbicides for weed control. 

BCS’ studies demonstrate TwinLinkTM Cotton is essentially indistinguishable from other cotton 

varieties used in terms of agronomic characteristics and cultivation practices (

Preferred Alternative: Cropping Practices: Crop Rotation and Pesticide Use

Scott, 2008; 

USDA-APHIS, 2010b). Therefore, cotton crop rotation practices are expected to be unchanged

under the Preferred Alternative. 

If TwinLinkTM Cotton is adopted, a continued reduction in the use of budworm/bollworm 

insecticides applications and the number of acre-treatments per year as reported in Benbrook’s 

trend analysis is expected to occur. The deregulation of TwinLinkTM Cotton will provide 

growers with another alternative Bt cotton variety to cultivate. Herbicide use patterns have the 

potential to change as well. The introduction of TwinLinkTM Cotton provides a stacked variety, 

expressing Bt-based lepidopteran resistance combined with tolerance to glufosinate ammonium, 

an alternative herbicide. TwinLinkTM Cotton provides growers with an alternative to those 

cotton varieties resistant to glyphosate, thus expanding options in the field for weed control.

In those fields where glyphosate-resistant weeds have emerged, glufosinate ammonium tolerance 

provides the grower with an option to transition away from glyphosate herbicides to a different 

post-emergent herbicide. The transition to glufosinate ammonium could reduce applications of 

those other herbicides needed to manage glyphosate-resistant weeds.

A determination of nonregulated status of TwinLinkTM Cotton is not expected to result in 

changes in the current cotton cropping practices. APHIS has determined that there are no past, 

present, or reasonably foreseeable actions that would aggregate with effects of the proposed 

action to affect changes in crop rotation. Studies demonstrate TwinLinkTM Cotton is essentially 

indistinguishable from other cotton varieties used in terms of agronomic characteristics and 

cultivation practices (

Cumulative Effects: Cropping Practices: Crop Rotation and Pesticide Use

Scott, 2008). 

It is anticipated that the trend of reduced broad-spectrum insecticide use by cotton growers will 

continue due to the adoption of Bt cotton and other cultural practices. There is the potential that 

the introduction of glufosinate ammonium tolerance may result in a reduction in total herbicide 

use as growers adopt different herbicide treatment strategies involving glufosinate ammonium as 
BAYER TWINLINKTM COTTON

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a post-emergent crop treatment, thereby reducing the use of some of the other herbicides which 

have been required in response to the emergence of glyphosate-resistant weeds. 

4.2.3 Seed Production 

As discussed in Subsection 2.2.3, cotton seed production is managed through the AOSCA 

standard procedures to preclude gene flow between species and varieties (Wozniak, 2002). 

Common practices include: 1) maintaining isolation distances to prevent pollen movement from 

other cotton sources; 2) planting border or barrier rows to intercept pollen; 3) employing natural 

barriers to pollen; and 4) field monitoring for off-types, other crops, weeds, and disease.

Under the No Action Alternative, current cotton seed production practices are not expected to 

change. 

No Action: Seed Production

The production of cotton seed for TwinLinkTM Cotton will be conducted consistent with these 

standard practices; consequently, no changes to seed production practices are required. Based on 

the data provided by BCS for TwinLinkTM Cotton (

Preferred Alternative: Seed Production

Scott, 2008), as well as previous experience 

with other Bt cotton varieties that have been widely adopted by growers since their introduction 

in 1996 (USDA-ERS, 2010a), APHIS has concluded that the availability of TwinLinkTM Cotton

would not alter the agronomic practices, locations, and seed production and quality 

characteristics of conventional and GE seed production (USDA-APHIS, 2010b). The 

deregulation of TwinLinkTM Cotton will not require a change to seed production practices. 

Based on current acreage trends, GE cotton varieties will likely continue to dominate. To the 

extent that growers see value in the traits offered by TwinLinkTM Cotton, this new variety may 

replace existing cotton varieties, both conventional as well as GE. The availability of 

TwinLinkTM Cotton is not anticipated to change cultivation areas for cotton production in the 

U.S. Because changes in the agronomic practices and locations for cotton seed production 

using TwinLinkTM Cotton are not expected, no cumulative effects have been identified for seed 

production. 

Cumulative Impacts: Seed Production

4.2.4 Organic Farming 

Organic production plans prepared pursuant to the National Organic Program (NOP) include 

practical methods to protect organically-produced crops from accidental contamination with GE 

materials. Typically, organic growers use more than one method to prevent unwanted material 

from entering their fields including: isolation of the farm, physical barriers or buffer zones 

between organic production and non-organic production, as well as formal communications 

between neighboring farms (Baier, 2008; Guerena and Sullivan, 2003; NCAT, 2003). These 

practices follow the same system utilized for the cultivation of certified seed under the AOSCA 

procedures.
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APHIS recognizes that producers of non-GE cotton, particularly producers who sell their 

products to markets sensitive to genetically engineered traits (e.g., organic or some export 

markets), can be reasonably assumed to be using practices on their farm to protect their crop 

from unwanted substances and thus maintain their price premium. APHIS will assume that 

growers of organic cotton are already using, or have the ability to use, these common practices 

as APHIS’s baseline for the analysis of the alternatives.

Current availability of seed for conventional (both GE and non-GE) cotton varieties, and those 

cotton varieties that are developed for organic production, is expected to remain the same under 

the No Action Alternative. Commercial production of conventional and organic cotton is not 

expected to change and will likely remain the same under the No Action Alternative. Planting 

and production of GE, non-GE, and organic cotton will continue to fluctuate with market 

demands, as it has over the last 10 years, and these markets are likely to continue to fluctuate 

under the No Action Alternative (

No Action: Organic Farming 

USDA-ERS, 2010c, 2010e). 

Transgenic cotton lines including those that are resistant to lepidopteran insects and herbicidetolerant are already in widespread use by farmers. TwinLinkTM Cotton should not present any 

new and different issues and impacts for organic and other specialty cotton producers and 

consumers. 

Preferred Alternative: Organic Farming 

Organic producers employ a variety of measures to manage identity and preserve the integrity 

of organic production systems (NCAT, 2003). The trend in the cultivation of GE cotton, nonGE, and organic cotton varieties, and the corresponding production systems to maintain varietal 

integrity, are likely to remain the same as the No Action Alternative.

According to the petition, agronomic trials conducted between 2005 and 2008 in a variety of 

locations in the U.S. demonstrated that TwinLinkTM Cotton is not significantly different in plant 

growth, yield, and reproductive capacity from its nontransgenic counterpart (USDA-APHIS, 

2010b). No differences were observed in pollen diameter, weight, and viability. Therefore, 

TwinLinkTM Cotton is expected to present a similar risk of cross-pollination as existing cotton 

cultivars. The practices currently employed to preserve and maintain purity of organic 

production systems would not be required to change to accommodate the production of 

TwinLinkTM Cotton. 

Historically, organic cotton production represents a small percentage (approximately, 0.1%) 

of total U.S. cotton acreage (USDA-ERS, 2010e). It will likely remain small regardless of 

whether new varieties of GE or non-GE cotton varieties, including TwinLinkTM Cotton, 

become available for commercial cotton production. 

Accordingly, the deregulation of TwinLinkTM Cotton is not expected to have a significant impact 

on organic cotton production.
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A determination of nonregulated status of TwinLinkTM Cotton is not expected to change the 

market demands for GE cotton or cotton produced using organic methods. A determination 

of nonregulated status of TwinLinkTM Cotton could add another GE cotton variety to the 

conventional cotton market. Based upon recent trend information, adding GE varieties to the 

market is not related to the ability of organic production systems to maintain their market share. 

Although 12 GE cotton events or lines were deregulated pursuant to Part 340 and the Plant 

Protection Act, between 2000 and 2008, the total acreage associated with the organic production 

of cotton remained at slightly above 15,000 acres (

Cumulative Effects: Organic Farming 

USDA-ERS, 2010e).

4.2.5 Specialty Cotton Production

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 conventional or genetically engineered 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; NCAT, 2003; Wozniak, 2002). 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). 

Current availability of seed for specialty cotton varieties are expected to remain the same under 

the No Action Alternative. 

No Action: Specialty Systems

As noted in the discussion of Seed Production, no changes in the production of seed or 

cultivation of cotton are required to accommodate TwinLinkTM Cotton.

Preferred Alternative: Specialty Systems 

It is unlikely that specialty system farmers, or other farmers who choose to plant nontransgenic 

varieties or sell nontransgenic seed, will be substantially impacted by the expected commercial 

use of TwinLinkTM Cotton. Transgenic cotton lines including those that are resistant to 

lepidopteran insects and express herbicide tolerance are already in widespread use by farmers. 

TwinLinkTM Cotton should not present any new and different issues and impacts for specialty 

cotton producers and consumers. 

According to the petition, agronomic trials conducted between 2005 and 2008 in a variety of 

locations in the U.S. demonstrated that TwinLinkTM Cotton is not significantly different in plant 

growth, yield, and reproductive capacity from its nontransgenic counterpart (USDA-APHIS, 

2010b). No differences were observed in pollen diameter, weight, and viability. Therefore, 

TwinLinkTM Cotton is expected to present a similar risk of cross-pollination as existing cotton 

cultivars including other GE cotton varieties. The practices currently employed to preserve and 

maintain purity of specialty cotton production systems would not be required to change to 

accommodate the production of TwinLinkTM Cotton. A determination of nonregulated status of

TwinLinkTM Cotton under the Preferred Alternative would not change the availability and 
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47

genetic purity of seed for specialty cotton varieties. Conventional management practices and 

procedures, as described previously for cotton seed production, proper seed handling, protection 

of wild relatives of cotton, and organic cotton farming, are in place to maintain the genetic 

diversity of cotton. Cotton growers have utilized these methods effectively to meet the standards 

for the production of specialty crop seed. Impacts would be similar to the No Action Alternative.

A determination of nonregulated status of TwinLinkTM Cotton is not expected to change the 

market demands for GE cotton or cotton produced using specialty systems. A determination of 

nonregulated status of TwinLinkTM Cotton will add another GE cotton variety to the cotton 

market. Between 2000 and 2009, 12 GE cotton events or lines were deregulated pursuant to 

Part 340 and the Plant Protection Act. Based on demonstrated agronomic characteristics and 

cultivation practices, and because the market share of specialty cotton varieties is unlikely to 

change by the introduction of TwinLinkTM Cotton, APHIS has determined that there are no past, 

present, or reasonably foreseeable changes that would impact specialty cotton producers and 

consumers. 

Cumulative Effects: Specialty Systems 

4.3 PHYSICAL ENVIRONMENT

4.3.1 Water Resources

Although cotton has been developed as a drought-tolerant crop (Cotton Incorporated, 2010b),

irrigation (used on approximately 35% of the U.S. cotton acreage) produces much higher cotton 

yields (Cotton Incorporated, 2010a). Despite high production levels in irrigated areas, 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 Incorporated, 2010b). In these 

areas, cotton has been displaced by higher value crops and land uses (Cotton Incorporated, 

2010b). 

Water quality is also preserved in modern cotton productions systems. The increase in 

conservation tillage practices has resulted in a reduction of runoff from agricultural lands, 

decreasing non-point source pollution of suspended sediment, fertilizer, and pesticides. Intensive 

monitoring of surface water and groundwater proximate to agricultural fields has demonstrated 

the benefits of no-till cotton in protecting both ground and surface water resources University of 

Tennessee Agricultural Extension Service, 2010

(

). Better nutrient management and precision 

technologies are ensuring inputs are used by the crop and are not entering ground or surface 

waters (Cotton Incorporated, 2010a).

Under the No Action Alternative, current land acreage and agronomic practices, including 

irrigation, tillage, and nutrient management associated with cotton production would not be 

expected to change. Therefore, no expected changes to water use associated with cotton 

production is expected for this alternative. 

No Action: Water Use
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In 2010, GE cotton occupied 93% of the cotton acreage (

Preferred Alternative: Water Use 

USDA-ERS, 2010c). Conventional 

and GE cotton production occurs on land that is dedicated to crop production and most cotton 

is planted in fields that have been in crop production for years (USDA-APHIS, 2010a). The 

introduction of GE cotton has resulted in the adoption of conservation practices (Cotton 

Incorporated, 2010a). These conservation practices, including reduced tillage and precision 

agriculture play a significant role in water conservation and maintaining water quality by 

minimizing soil erosion (USDA-NRCS, 2006b).

TwinLinkTM 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, a determination of 

nonregulated status of TwinLinkTM Cotton will not change the current use of irrigation 

practices in commercial cotton production. Because the TwinLinkTM Cotton is expected to 

simply replace GE and non-GE cotton varieties already in use, the consequences of the 

Preferred Action Alternative on water use are the same as the No Action Alternative.

No cumulative effects on water use have been identified for a determination of nonregulated 

status of TwinLinkTM Cotton. A determination of nonregulated status of TwinLinkTM Cotton

would not change the water use and irrigation practices used in commercial cotton production. 

Cumulative Effect: Water Use 

4.3.2 Soil 

This section discusses the potential consequences of the No Action and the Preferred 

Alternatives on soil. The USDA Natural Resources Conservation Service (NRCS) has 

identified significant reductions in the loss of soil from croplands in the U.S., finding that total 

soil loss on highly erodible croplands and non-highly erodible cropland decreased by 39.2% 

from 1982 to 2003 (USDA-NRCS, 2006b). Over the last 10 years, cultivation of herbicidetolerant cotton has contributed to this reduction in soil loss through a shift towards conservation 

tillage and the use of cover crops (Cotton Incorporated, 2010c). 

Increases in total acres dedicated to conservation tillage have been attributed to an increased use 

of genetically modified crops which eliminates the need for mechanical weed control (Alabama 

Cooperative Extension System, 1996; McClelland et al., 2000; Towery and Werblow, 2010; 

USDA-NRCS, 2010). 

Additional soil quality benefits from adoption of GE cotton may also be realized by reducing the 

risks associated with environmental spills or misapplications of chemical insecticides to the soil, 

and reductions in the frequency with which insecticides must be applied. 

Land acreage and agronomic practices associated with traditional and existing non-regulated 

GE cotton production would not be expected to change in response to the No Action 

Alternative. 

No Action: Soil
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Continued adoption of existing deregulated GE cotton varieties would be expected. In 2010, 

GE cotton occupied 93% of the cotton acreage (USDA-ERS, 2010c). Conventional and GE 

cotton production occurs on land that is dedicated to crop production and most cotton is planted 

in fields that have been in crop production for years (USDA-APHIS, 2010a). 

Current agronomic practices associated with cotton production including tillage, cultivation, 

applications of pesticides and fertilizer, and the use of agricultural equipment would not be 

expected to change if TwinLinkTM Cotton is still a regulated article. To the extent that currently 

available GE cotton varieties can result in the grower’s adoption of conservation tillage, soils 

would be positively affected by that adoption. 

No changes to agronomic practices typically applied in the management of conventional cotton, 

including other commercially available GE cotton varieties, are required for TwinLinkTM Cotton. 

Preferred Alternative: Soil 

BCS’ field trial and laboratory analyses demonstrated that the agronomic performance of 

TwinLinkTM Cotton was functionally identical to its non-transgenic counterpart, the Coker 315

cultivar (Scott, 2008). No increases in fertilizers and pesticides were required, nor were any 

changes in cultivation, planting, harvesting, and volunteer control required (Scott, 2008). It is 

expected that similar agronomic practices that are currently used for commercially available GE

cotton will also be used by growers of TwinLinkTM Cotton. If TwinLinkTM Cotton is adopted 

and replaces non-GE cotton varieties, soils currently under non-GE cotton production may 

benefit from the use of TwinLinkTM Cotton due to a reduction in applications and the number of 

acre-treatments per year required for both insecticide and herbicide applications. Soils would 

also benefit from the reduction in soil disturbance because of fewer passes by heavy farm 

equipment. 

It is expected that only glufosinate ammonium would be applied as a post-emergent herbicide 

on TwinLinkTM Cotton. Glufosinate ammonium has been shown to rapidly dissipate from most 

agricultural ecosystems across a wide range of soil and climatic conditions, with a median soil 

half-life (the time it takes for half of the glufosinate ammonium to dissipate in the soil) of 7.5 

days (PPDB, 2010). When used in accordance with the label, glufosinate ammonium

accumulation in soil has not been shown to be significant.

The bar gene which has been introduced into TwinLinkTM Cotton was originally isolated from 

Streptomyces hygroscopius, a common soil bacteria (Scott, 2008). The PAT enzyme produced 

by the TwinLinkTM Cotton is naturally occurring in the soil (CFIA, 2004). The cultivation of 

TwinLinkTM Cotton and the attendant production of the PAT enzyme will therefore not cause an 

impact to the physicochemical characteristics of the soil.

As explained above, if TwinLinkTM Cotton is adopted and cultivated, there may be positive 

impacts to soil when compared with traditional cotton cultivation practices.

APHIS has not identified any cumulative effects of the use of TwinLinkTM Cotton to soils. 

Bayer has compared phenotypic, agronomic, and cultivation characteristics between TwinLinkTM 

Cumulative Effects: Soil 
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Cotton and control cottons (Scott, 2008). TwinLinkTM Cotton required the same soil, fertilizer, 

water and pest management practices (except for lepidopteran pest control) as non-GE cotton 

(Scott, 2008). Consequently, the phenotypic, agronomic, and ecological data presented by BCS 

(Scott, 2008) support the conclusion by APHIS that TwinLinkTM Cotton will not result in any 

significant impact to the soil that is not already found in conventional cotton production 

practices. 

Based on these findings, and because the amount of cotton grown in the U.S. is unlikely to 

change by the introduction of TwinLinkTM Cotton, APHIS has determined that there are no 

cumulative impacts to soil. 

4.3.3 Air Quality

Traditional 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 nitrous oxide emissions from the use of nitrogen 

fertilizer (Aneja et al., 2009; Hoeft et al., 2000; USDA-NRCS, 2006c). 

The adoption of GE cotton has reduced air emissions from several of these sources. 

Conservation practices, including conservation tillage associated with GE cotton production 

requires fewer tractor passes across a field, thus decreasing dust generation and tractor 

emissions; surface residues and untilled organic matter physically hold the soil in place thus 

decreasing wind erosion of soils and pesticide drift in wind-eroded soils (Baker et al., 2005; 

Cotton Incorporated, 2010d; USDA-NRCS, 2006c). Reduced tillage also increases sequestration 

rates of carbon emissions in soils (Causarano et al., 2006). This section discusses the potential 

consequences of the No Action and the Preferred Alternatives on air quality. 

Under the No Action Alternative, current impacts to air quality associated with land acreage and 

cultivation practices associated with cotton production would not be affected. 

No Action: Air Quality 

Adoption of GE cotton varieties would be expected to continue. To the extent that the 

adoption and cultivation of GE cotton varieties allows the grower to implement conservation 

practices, air quality improvement associated with these practices would be expected to 

follow. Air quality would continue to be affected by agronomic practices associated with 

conventional methods of cotton production such as tillage, cultivation, pesticide and fertilizer 

applications, and the use of agricultural equipment. 

TwinLinkTM Cotton production does not change land acreage or any cultivation practices for 

conventional, transgenic, or non-transgenic cotton production. There are no expected 

increases in cultivation, planting, pesticide use, fertilizer use, harvesting, or volunteer control 

compared to currently available GE and non-GE cotton cultivars. It is expected that similar 

agronomic practices that are currently used for commercially available Bt cotton or herbicidetolerant cotton will also be used by growers of TwinLinkTM Cotton. 

Preferred Alternative: Air Quality
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If TwinLinkTM Cotton is adopted and replaces non-GE cotton varieties, air quality issues 

associated with pesticide application and use in non-GE cotton production may benefit from 

the use of TwinLinkTM Cotton due to a reduction in the application of lepidopteran targeted

insecticides and similar reductions in herbicide applications required as growers take 

advantage of the post-emergent herbicide glufosinate ammonium. The collective impact is a 

reduction in the number of acre-treatments per year requiring the use of heavy farm 

equipment, with a positive impact on air quality associated with the decrease in equipmentrelated emissions, as well as a decrease in dusts and pesticide drifts.

Based on this information, APHIS concludes that the production of TwinLinkTM Cotton is not 

expected to adversely affect air quality and, in fact, may provide some benefit. However, 

considering the wide adoption of similar GE cotton lines, overall impacts are likely to be 

similar to the No Action Alternative. 

Based on the findings described above, APHIS has determined that 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 air quality. The consequences of the Preferred Action 

Alternative on commercial cotton production and the resulting air quality are similar to those 

expected for the No Action Alternative.

Cumulative Effects: Air Quality

4.3.4 Climate Change

Agriculture, including land-use changes for farming, is responsible for an estimated 6% of all 

human-induced GHG emissions in the U.S. Moreover, nitrous oxide (N2O) emissions from 

agricultural soil management (primarily fertilizer use) represent 68% of all U.S. N2

US-EPA, 2010b

O emissions 

( ). A more comprehensive discussion of the contribution of agricultural 

practices to GHGs is provided in Subsection 2.3.4, Affected Environment – Climate Change. 

Agriculture-related GHG emissions include carbon dioxide (CO2), N2O, and methane (CH4), 

produced through the combustion of fossil fuels to run farm equipment; the use of fertilizers; or 

the decomposition of agricultural waste products including crop residues, animal wastes, and 

enteric emissions from livestock. This section discusses the potential consequences of the No 

Action and the Preferred Alternatives on climate change.

Under the No Action Alternative, environmental releases of TwinLinkTM Cotton would be under 

APHIS regulation. Due to the limited size of these field trials, there would be no measurable 

effect on climate change from these confined environmental releases. Land acreage and 

cultivation practices associated with cotton production would not be affected. Current 

agronomic practices associated with conventional cotton production and current GE cotton 

varieties which contribute to GHG emissions, including tillage, cultivation, irrigation, pesticide 

application, fertilizer applications and use of agriculture equipment, would not be expected to 

change if TwinLinkTM Cotton remains a regulated article. To the extent that the adoption and 

cultivation of GE cotton varieties allows the grower to implement conservation practices, GHG 

No Action: Climate Change
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52

emissions would be expected to be reduced commensurate with the air quality improvements

anticipated from adoption of conservation tillage practices.

A determination of nonregulated status of TwinLinkTM Cotton would not change the 

cultivation or agronomic practices, or agricultural land acreage associated with growing 

cotton, and thus is expected to have the same effect on climate change as the No Action 

Alternative.

Preferred Alternative: Climate Change

APHIS has not identified any cumulative effects for this issue. The use of TwinLinkTM Cotton

in commercial cotton production is not expected to cause any cumulative effect on climate 

change because APHIS does not anticipate any changes in cotton production practices or an 

expansion of cotton acreage as a result of TwinLinkTM Cotton deregulation. The 

consequences of the Preferred Action Alternative on commercial cotton production and 

acreage are the same as for the No Action Alternative.

Cumulative Effects: Climate Change

4.4 ANIMAL AND PLANT COMMUNITIES

4.4.1 Animals

Cotton production systems in agriculture are host to many animal species. A variety of insects 

feed on cotton plants or prey upon other insects inhabiting cotton fields. In addition, mammal 

and bird species use cotton fields and adjacent vegetation for food and habitat throughout the 

year. This section discusses the potential consequences of the No Action and the Preferred 

Alternatives on animal populations associated with cotton production. The cumulative effects 

analysis for this issue is found discussed below under “Cumulative Effects: Animals, Plants, 

and Biodiversity” in Subsection 4.4.3.

Under the No Action Alternative, conventional and GE transgenic cotton production will 

continue while TwinLinkTM Cotton remains a regulated article. Potential impacts of GE and 

non-GE cotton production practices on non-target species would be unchanged. 

No Action: Animals 

BCS data indicates that the agronomic practices used to produce TwinLinkTM Cotton will be the 

same as those used to produce other conventionally grown GE and non-GE cotton. TwinLinkTM 

Cotton production will not change land acreage or any cultivation practices for cotton 

production. 

Preferred Alternative: Animals 

Since the mid-1990s, transgenic cotton lines have been commercialized without substantiated 

reports of significant deleterious impacts on non-target organisms (Mendelsohn et al., 2003; 

OECD, 2007; US-EPA, 2008a; USDA-APHIS, 2010a). Evidence submitted by BCS from 
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53

laboratory and field studies as well as other peer reviewed studies demonstrate a lack of toxicity 

of the TwinLinkTM Cotton on non-target representative species (Scott, 2008). 

BCS has presented laboratory test data with indicator test species to determine potential toxicity 

of Cry enzyme toxin at doses higher than would be anticipated under field conditions (Rose et 

al., 2007). BCS’ selection of representative indicator test species was based upon their potential 

for exposure to the Cry1Ab and Cry2Ae proteins. BCS submitted non-target data for two 

above-ground arthropods (Ladybug, Coleomegilla maculate; and Lacewing, Chrysoperla 

carnea); a soil-dwelling insect (springtail, Folsomia candida); a pollinator (honeybee, Apis 

mellifera); a mammal (house mouse, Mus musculus); and an aquatic invertebrate (water flea,

Daphnia magna) (Scott, 2008). The data submitted in the petition indicate that no significant 

adverse effects were observed at the maximum test dose for either of the two Cry proteins for 

any of the tested species. Other research has also shown no direct adverse effects on 

insectivorous insects in field and laboratory studies with transgenic plants expressing Cry 

proteins (Marvier et al., 2007; Naranjo, 2009b; Romeis et al., 2006; Shelton et al., 2009). 

The non-target risks associated with exposure of aquatic organisms is likely very low because 

cotton pollen is large, sticky, and is not transported long distances by the wind (USDA-APHIS, 

2010a). Seed and plant debris are not expected to be readily transported via overland runoff or 

wind to aquatic habitats (USDA-APHIS, 2010a). Moreover, because the specific intestinal and 

midgut receptors for the Bt endotoxin are not present in vertebrates, these insecticidal proteins 

are not expected to adversely affect these organisms (Hofmann et al., 1988a; Hofmann et al., 

1988b; Shimada et al., 2006b; US-EPA, 2008a; Van Rie et al., 1989; Van Rie et al., 1990). 

An additional advantage of the use of transgenic cotton producing the Bt proteins is the 

corresponding reduction in use of broad spectrum insecticides1

Cattaneo et al., 2006

and the consequent reduction of

potential impact on diversity of non-target insects ( ; Dively, 2005; Marvier 

et al., 2007; Naranjo, 2005a; Romeis et al., 2006; Torres and Ruberson, 2005; Torres et al., 2006; 

Whitehouse et al., 2005). Several authors note that insect-resistant crops had a higher diversity 

and abundance of non-target animals than conventionally grown crops (Hardee et al., 2001; 

Moar et al., 2003; Sanvido et al., 2006; Sisterson et al., 2007). 

BCS has filed applications with the FDA and the EPA for the TwinLinkTM Cotton variety. The 

FDA and EPA are currently reviewing the information submitted by the applicant. Both 

agencies have previously reviewed and approved comparable products, including several crop 

varieties expressing the Bt-based Cry proteins as plant-incorporated protectants, as well as the 

bar gene, resulting in the expression of the PAT enzyme providing tolerance to glufosinate 

 

1 Broad spectrum insecticides are chemical insecticides which kill insects that are causing injury to plants and also 

kill other insects that are not causing injury to the plant. Insects that are inadvertently killed by the application of 

insecticide are called “non-target” insects. Because the Cry proteins are specific for a narrow range of lepidopteran 

insects, use of Cry proteins to control plant pests is recognized as being beneficial to the survival of non-target 

insects (US-EPA, 2008a). 
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54

ammonium. In the absence of a completed FDA and EPA determinations, APHIS takes into 

consideration prior agency reviews of comparable products to conduct its assessment of the 

potential impacts.

EPA has issued a tolerance exemption for Cry1Ab protein in all crops (40 CFR §174.511; USEPA, 2010d), as well as for the PAT protein (40 CFR §174.522; US-EPA, 2010g). A temporary 

exemption from the requirement of a tolerance has been issued for Cry2Ae (40 CFR §174.530; 

US-EPA, 2010e). 

The PAT enzyme bar gene construct was deregulated by APHIS in 2003 in the BCS 

LibertyLink® Cotton (USDA-APHIS, 2003). In 2003, the FDA completed its food safety 

consultation on LibertyLink®

US-FDA, 

2003

Cotton and granted tolerance exemptions for both the plantincorporated protectant, as well as the genetic material necessary for its production (

). The EPA granted exemptions from the requirement of a tolerance for residues of 

glufosinate ammonium, as well as the plant-pesticide PAT in or on food and feed commodities of 

cotton (see: 62 FR 17719; 40 CFR §180.473; US-EPA, 2010c).

The conclusions presented by the EPA and the FDA were based upon their independent reviews 

of human health and environmental impacts associated with exposure to and consumption of 

plant material incorporating the bar gene and expressing the PAT enzyme. In both cases, these 

agencies determined that the cottonseed, refined oil, and cotton seed meal derived from the 

LibertyLink®

Similar international reviews and approvals have been published for the LibertyLink

variety was not materially different in composition, safety and nutritional value 

from other cotton varieties then on the market. 

® Cotton. 

The Australia and New Zealand Food Authority (ANZFA) completed a Toxicological Review 

and Risk Assessment, and a Technical Report was published in 2005 in which ANZFA 

concluded that LibertyLink®

ANZFA, 2005

Cotton was comparable to non-genetically engineered (non-GE) 

cotton in terms of their safety and nutritional adequacy ( ). In 2004, the Plant 

Biosafety Office (PBO) of the Canadian Food Inspection Agency (CFIA) also concluded that 

BCS’ LibertyLink®

CFIA, 2004

Cotton was substantially equivalent to currently grown cotton in terms of 

their potential environmental impact and livestock feed safety, and the novel traits would not 

have any substantial negative effect on the environment ( ). The CFIA specifically 

noted that the PAT enzyme responsible for glufosinate ammonium tolerance has very specific 

enzymatic activity associated with the acetylation of glufosinate ammonium, and is rapidly 

inactivated in mammalian stomach and intestinal fluids by enzymatic degradation and pH 

mediated proteolysis (CFIA, 2004).

To the extent that TwinLinkTM Cotton displaces conventional, non-GE cotton varieties, the 

expression of the stacked Cry proteins providing lepidopteran resistance in conjunction with the 

tolerance to glufosinate ammonium may have an overall positive impact on animals. As 

previously discussed in the analysis of water, soil, in those fields where TwinLinkTM Cotton is 

cultivated, growers would be expected to reduce their use of pesticides for control of 

lepidopteran pests and take advantage of the weed control offered by glufosinate ammonium, 

thus allowing for a shift to increased conservation practices. 
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55

The use of insecticides other than Bt crops may affect non-target organisms including honey 

bees, soil invertebrates, or culturable microbial flora (Dively and Rose, 2003; US-EPA, 2010a). 

The cultivation of insect-resistant crops allows a reduction and replacement of broad-spectrum 

insecticides, with a corresponding positive effect on biodiversity, including non-target insects 

(Cantrell, 2006). A notable advantage of GE insecticidal (Bt) crops over conventional 

insecticides is the high specificity of the Bt toxins, which minimize the potential toxic effects on 

non-target insects (Bigler et al., 2008; Sanvido et al., 2006). 

The incorporation of glufosinate ammonium tolerance provides several potential advantages over 

conventional weed management programs, including increased flexibility to manage problem 

weeds, reduced use of soil-applied herbicides, reduced total use of herbicides, and more 

widespread adoption of conservation tillage (O'Sullivan and Sikkema, 2004). The associated 

adoption of conservation tillage and reduced use of soil-applied herbicides have the potential to 

positively impact animal populations in fields planted with TwinLinkTM Cotton (see, e.g., Eggert 

et al., 2004).

Based on the above information, APHIS concludes that the deregulation and cultivation of 

TwinLinkTM Cotton is expected to have no adverse effects on non-target animals. Overall 

impacts would be similar to the No Action Alternative.

4.4.2 Plants

The landscape surrounding a cotton field may be bordered by other cotton (or any other crop) 

fields or may also be surrounded by woodland, rangelands, and/or pasture/grassland areas. 

These plant communities represent natural or managed plant buffers for the control of soil and 

wind erosion and also serve as habitats for a variety of transient and non-transient wildlife 

species. The potential impacts to off-site plant communities is discussed in Subsection 4.4.3, 

Biological Diversity.

Weed control programs are important aspects of cotton cultivation. In this context, weeds are 

those plants which, when growing in the cotton field, compete with the cotton for space, water, 

nutrients, and sunlight, and may thus include native species (University of California IPM 

Online, 2008b). The types of weeds in and around a cotton field will vary depending on the 

geographic region where the cotton is grown. Common weeds in cotton include grasses, broadleaf weeds, and sedges (Cyperus spp.). Some of these have been discussed in Subsection 4.2.2, 

Cropping Practices. This section discusses the potential consequences of the No Action and the 

Preferred Alternatives on plants. The cumulative effects analysis for this issue is discussed 

below under “Cumulative Effects: Animals, Plants, and Biodiversity” in Subsection 4.4.3.

Under the No Action Alternative, environmental releases of TwinLinkTM Cotton would be 

under APHIS regulation. Plant species (i.e., weeds) that typically inhabit GE and non-GE 

cotton production systems will continue to be managed through the use of mechanical, 

cultural, and chemical control methods.

No Action: Plants 
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In the event of a determination of nonregulated status of TwinLinkTM Cotton , the risks to wild 

plants and agricultural productivity from weedy cotton populations are low; volunteer cotton 

populations are easily managed and feral populations occur rarely in the U.S. Cotton Belt 

(

Preferred Alternative: Plants 

Wozniak, 2002). 

Agronomic studies conducted by BCS tested the hypothesis that the weediness potential of 

TwinLinkTM Cotton is unchanged with respect to conventional cotton (Scott, 2008). No 

differences were detected between TwinLinkTM Cotton and nontransgenic cotton in growth, 

reproduction, or interactions with pests and diseases, other than the intended effect of protection 

from lepidopteran pests. The main natural controls on feral populations of cotton are poor seed 

dispersal, poor seed germination, competition from other plants, and a high requirement for 

moisture (US-EPA, 2001b). Therefore, the incorporation of either the insect resistance trait or 

the herbicide tolerance trait is unlikely to appreciably improve seedling establishment and 

increase weediness potential. Any TwinLinkTM Cotton volunteers could be readily controlled by 

other readily available herbicides, including glyphosate (Miller et al., 2004; Stewart et al., 2003). 

The incorporation of glufosinate ammonium tolerance provides several potential advantages over 

conventional weed management programs, including increased flexibility to manage problem 

weeds, reduced use of soil-applied herbicides, reduced total use of herbicides, and more 

widespread adoption of conservation tillage (O'Sullivan and Sikkema, 2004). The associated 

adoption of conservation tillage and reduced use of herbicides have the potential to positively 

impact plant populations in fields and fallow areas adjacent to those planted with TwinLinkTM 

Cotton (see, e.g., Eggert et al., 2004).

The effect of cotton production on plant communities is likely to be unchanged by the 

introduction of TwinLinkTM Cotton. Overall impacts would be similar to the No Action 

Alternative.

4.4.3 Biological Diversity

Biodiversity in an agroecosystem depends on four primary characteristics: 1) diversity of 

vegetation within and around the agroecosystem; 2) permanence of various crops within the 

system; 3) intensity of management, including selection and use of insecticides and herbicides; 

and 4) extent of isolation of the agroecosystem from natural vegetation (Altieri, 1999). The 

introduction of woodlots, fencerows, hedgerows, wetlands, etc. is one way to enhance

biodiversity in large scale monocultures. Additional enhancement strategies include 

intercropping (the planting of two or more crops simultaneously to occupy the same field), 

agroforestry, crop rotations, cover crops, no-tillage, composting, green manuring (growing a crop 

specifically for the purpose of incorporating it into the soil in order to provide nutrients and 

organic matter), addition of organic matter (compost, green manure, animal manure, etc.), as 

well as the introduction of hedgerows and windbreaks (Altieri, 1999). To some degree these 

practices currently are being utilized by cotton growers to increase biodiversity (Cotton 

Incorporated, 2010a). The adoption of GE crops, with the concomitant reduction in insecticide 

use and enhanced soil conservation practices, has also contributed to the increase in biodiversity 
BAYER TWINLINKTM COTTON

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of soil microorganisms, beneficial organisms, and plants (Dively and Rose, 2003; Naranjo, 

2009a; Sanvido et al., 2006).

Under the No Action Alternative, TwinLinkTM Cotton would continue to be a regulated article. 

Growers and other parties who are involved in production, handling, processing, or consumption 

of cotton would continue to have access to existing deregulated GE lepidopteran-resistant (Bt) 

cotton products, herbicide-tolerant cotton products, stacked varieties presenting both, and 

conventional cotton varieties. The implications of agronomic practices associated with cotton 

production, whether traditional or GE varieties, would not change. 

No Action: Biological Diversity 

The use of genetically modified cotton varieties currently available affects biological diversity 

by: 1) providing the opportunity to use conservation practices that enhance habitat creation; and 

2) decreasing the use of pesticides which in turn, limits the impact on the floral and faunal 

communities that can potentially inhabit the fields and immediate surroundings (

Preferred Alternative: Biological Diversity

Cotton 

Incorporated, 2010a; Naranjo, 2009a; Sanvido et al., 2006). Incorporation of herbicide tolerance 

in the crop allows the grower to adopt the use of no-till, cover crops, crop rotation, intercropping, 

and good ditch/border/hedgerow management, each of which contributes to biodiversity in and 

around cotton fields (Palmer and Bromley, 2010; Sharpe, 2010). The use of broad-spectrum 

insecticides is one of the most severe constraints for biological diversity in crops (USDAAPHIS, 2010a). One of the benefits of Bt cotton has been the reduction of broad-spectrum 

insecticide use during cotton production (Fernandez-Cornejo and Caswell, 2006). 

A comparison of non-transgenic and transgenic cotton production revealed no substantial impact 

on ant and beetle diversity in cotton fields; by contrast, broad-spectrum insecticide use 

demonstrated considerably reduced diversity in these populations (Cattaneo et al., 2006). Cotton 

expressing the Bt Cry proteins allows for the reduction in use of these broad spectrum 

insecticides, and is not expected to present a risk to beneficial insects and non-target pests. 

Research in Arizona has shown that Bt cotton has a minimum effect on both the number and 

function of foliar-dwelling arthropod natural enemies; on the other hand, broad-spectrum 

insecticide use caused a 48% reduction in 13 of the 22 taxa that were studied (Naranjo, 2005a, 

2005b). 

Bt toxin has been found to be present in every major part of Bt cotton plants (leaves, stems, and 

roots) (Vadakattu and Watson, 2004). Bt cotton roots were also found to release the Bt protein 

into the soil (Vadakattu and Watson, 2004). The effects of Bt on non-target soil microorganisms 

in Bt maize and Bt cotton cultivation found that microbial biodiversity and activity was not 

different from that of their non-Bt counterparts (EFSA, 2008; Hönemann et al., 2008; Icoz et al., 

2008; Shen et al., 2006).

Plant biodiversity associated with cotton cultivation is also an issue of concern. Although cotton 

fields are cultivated as monocultures to optimize cotton yield, areas surrounding a cotton field 

may harbor a wide variety of plants. Broad spectrum herbicides have the potential to impact offsite plant communities. Glufosinate ammonium provides opportunities to the grower to control 
BAYER TWINLINKTM COTTON

58

weeds in the field with fewer applications of herbicides than in traditional cultivation systems or 

those systems where glyphosate resistance has emerged (University of California IPM Online, 

2008b). Accordingly, adoption of a glufosinate ammonium protocol could minimize off-site 

impacts. The application processes for glufosinate ammonium allow the grower to apply fewer 

herbicides and reduce field cultivation. Reducing the number of applications of herbicides 

during the cotton production cycle minimizes instances of unintentional drift of these chemicals 

to adjacent fields, buffer zones, ditches, and fallow areas.

Although TwinLinkTM Cotton does provide the grower with a new choice for a herbicide-tolerant 

and insect-resistant variety, cultivation of TwinLinkTM Cotton does not otherwise require a 

change in the rates of fertilizer application, tillage, planting, or harvesting from existing 

commercial cotton varieties, including other GM cotton varieties providing either insect 

resistance, herbicide tolerance, or stacked with both (Scott, 2008). Therefore, the effect of cotton 

production on plant communities is likely to be unchanged by the introduction of TwinLinkTM 

Cotton. 

A determination of nonregulated status of TwinLinkTM Cotton will not change the cultivation or 

agronomic practices, or agricultural land acreage associated with growing cotton. TwinLinkTM 

Cotton would be an additional Bt cotton variety providing a different option for herbicide use 

(glufosinate ammonium) for growers to use and therefore is expected to have the same effect on 

biological diversity as the No Action Alternative.

Therefore, the deregulation of TwinLinkTM Cotton for the control of lepidopteran pests and 

tolerance of glufosinate ammonium is highly unlikely to have any direct toxic effects on nontarget organisms and is likely to be neutral or beneficial to animal and plant biodiversity 

compared to non-transgenic cotton managed with conventional broad-spectrum insecticides. 

APHIS has determined that there are no impacts from past, present, or reasonably foreseeable 

actions that would aggregate with effects of the proposed action to create cumulative impacts or 

reduce the long-term productivity or sustainability of any of the resources associated with the 

ecosystem in which TwinLinkTM Cotton is planted. Based on scientific evidence, the diversity 

and abundance of non-target organisms in lepidopteran-resistant cotton is at least as high as in 

conventional cotton; and in many studies, higher biodiversity is associated with transgenic cotton 

(

Cumulative Effects: Animals, Plants, and Biodiversity

Cattaneo et al., 2006; Head et al., 2005; Naranjo, 2005a, 2005b; Torres and Ruberson, 2007; 

Torres et al., 2006; Whitehouse et al., 2005). 

Cultivation of TwinLinkTM Cotton, with the attendant expression of the two stacked Cry proteins 

and the PAT enzyme providing herbicide tolerance, is highly unlikely to have direct toxic effects 

on non-target organisms and is likely to be neutral or beneficial to biodiversity compared with 

conventionally managed cotton. Therefore, the likelihood of adverse cumulative effects on nontarget organisms and biodiversity following the introduction of TwinLinkTM Cotton is minimal.

4.4.4 Gene Movement

Gene flow is the movement of genes from one organism to another. Vertical gene flow, or 

introgression, is the movement of genes to sexually compatible relatives (Ellstrand, 2003; Quist, 
BAYER TWINLINKTM COTTON

59

2010). In assessing the risk of gene introgression from TwinLinkTM Cotton to its sexually 

compatible relatives, APHIS considered two primary issues: 1) the potential for gene flow and 

introgression to feral upland cotton and cotton relatives and 2) the potential impact of 

introgression. This is discussed below under the “Preferred Alternative” heading.

Horizontal gene flow is the stable movement of genes from one organism to another without 

reproduction or human intervention (Keese, 2008; Quist, 2010). There is no evidence of 

naturally occurring transgene movement from transgenic crops to sexually incompatible species

(Scott, 2008; Stewart, 2008). Horizontal gene transfer and consequent expression of DNA from 

one plant to another plant or other phyla (e.g., species of bacteria) is unlikely to occur (Keese, 

2008). This event would require physical relocation of the complete genetic material from the 

transgenic plant to the new location, including not only the genes which code for the production 

of specific proteins, but also those portions of the genome which regulate the activity of those 

genes (Keese, 2008; Scott, 2008). There are no known naturally occurring vectors (such as 

plasmids, phages or transposable elements) that could be responsible for inter-domain gene 

transfer, and there is little evidence that eukaryotic cells are naturally capable of stably 

incorporating genes from the environment into their genome (Brown, 2003). Although viruses 

do move genetic material, all viruses that infect higher plants have small RNA or DNA genomes, 

usually with fewer than 20 encoded proteins (Keese, 2008). These viruses are therefore 

constrained as to the type and size of novel genetic material which can be acquired by horizontal 

gene transfer (Stewart, 2008). 

Two bacteria species commonly associated with plants, Agrobacterium and Rhizobium, have 

been evaluated to determine the probability of horizontal gene transfer between the bacterium 

and their host plants. Agrobacterium moves its genes from its bacterial plasmid to the plant 

causing the plant to produce the gall (abnormal outgrowth) (University of Illinois, 2010). 

Rhizobium aids in nitrogen fixation in legume nodules (Wilkinson and Elevitch, 2011). The 

genomes of both bacteria have been sequenced, and the sequenced genes evaluated for 

exogenous genes (Kaneko et al., 2000; Kaneko et al., 2002; Wood et al., 2001). Despite what 

would appear to be millennia of symbiotic relationships between these bacteria and their host 

plants, there is no evidence that these organisms contain genes derived from plants (USDAAPHIS, 2010a). In cases where review of sequence data implied that horizontal gene transfer 

occurred, these events are inferred to occur on an evolutionary time scale in the order of millions 

of years (Brown, 2003; Koonin et al., 2001). Transgene DNA promoters and coding sequences 

are optimized for plant expression, not bacterial expression (USDA-APHIS, 2010a). Horizontal 

gene flow, resulting in the relocation of entire transgenes including the regulatory portions of the 

DNA (those parts of the DNA which code for the production of the specific proteins in that 

relocated transgene) has never been shown to occur in nature (Clarke, 2007; Stewart, 2008).

Thus, even if horizontal gene transfer occurred, proteins associated with these transgenes are not 

likely to be produced in the new host organism (Stewart, 2008; USDA-APHIS, 2010a). Based 

on this information, APHIS considers the horizontal gene flow from TwinLinkTM Cotton to 

unrelated species to be highly unlikely, and the same as potential horizontal gene flow from 

existing GE cotton varieties. 

Under the No Action Alternative, conventional and GE transgenic cotton production will 

No Action: Gene Movement 
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continue while TwinLinkTM Cotton will remain a regulated article. Cotton land acreage and 

cultivation practices for both conventional and GE transgenic cotton varieties will remain the 

same. In 2010, Bt cotton varieties occupied 93% of the cotton acreage (USDA-ERS, 2010c). 

Gene flow from current commercially available GE cultivars to non-GE cotton cultivars, feral 

cotton populations, and wild sexually compatible relatives will remain unchanged from the 

current condition.

Under this alternative, TwinLinkTM Cotton would be available to growers, raising the potential 

for gene introgression of TwinLinkTM Cotton with other sexually compatible, related species. 

Preferred Alternative: Gene Movement

The passage of the transgene to a cross-compatible wild relative could allow the wild relative to 

become more abundant in the habitat or to invade new habitats because of its lepidopteran 

resistance (Wilkinson and Ford, 2007). This increased resistance of the wild relative to one 

group of insects could alter the balance of other insect herbivores, predators, and parasites 

(Wilkinson and Ford, 2007). The introgressed wild crop relative could also impact other plants 

through interspecific (between species) competition and indirectly affect the insect pollinators, 

herbivores, predators, and parasites of those species (Wilkinson and Ford, 2007). Vertical gene 

flow, or introgression, is influenced by many factors, including the subtle differences between 

flowers and pollinators in related species, the mode of seed dispersal, and habitat where the two 

species grow (Messeguer, 2003; Quist, 2010). Introgression can be managed by understanding 

these biological and physical barriers to pollen movement (Daniell, 2002; Eastham and Sweet, 

2002; Messeguer, 2003; Quist, 2010).

Two species of cotton are cultivated in the U.S.: upland cotton (G. hirsutum) and Pima cotton

(G. barbadense) (USDA-ERS, 2009). There are two wild relatives of interest to U.S. growers, 

G. thurberi and G. tomentosum, found in the mountains of southern Arizona and in Hawaii, 

respectively. APHIS has considered the potential for gene flow from TwinLinkTM Cotton, a GE 

variety of G. hirsutum, to other upland cotton varieties, as well as these other three species.

With regard to gene flow to other upland cotton varieties (G. hirsutum), such gene flow is 

controlled by careful adherence to isolation distances, border and barrier rows, and similar 

practices developed following AOSCA standards for identity protection of seeds. These 

measures have been developed based on research on the pollination of the upland cotton flower. 

Although upland cotton is considered self-pollinating (Hartman and Kester, 1975; Scott, 2008), 

cotton can be pollinated by bees. McGregor (1976) illustrated a rapid decline in the transfer of 

cotton pollen by bees over distance and found that at 150 to 200 feet away from the source plant, 

only 1.6% of the bees showed the presence of the source plant pollen particles. Very little pollen 

is transferred beyond 12 meters (McGregor, 1976; Scott, 2008; Vaissiere and Vinson, 1994). By 

comparison, the isolation distances for Foundation, Registered, and Certified seeds specified in 7 

CFR Part 201 are 1320, 1320, and 660 feet, respectively. If these identity practices are adhered 

to by growers, it is unlikely that TwinLinkTM Cotton will outcross to other upland cotton 

varieties.
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Upland cotton and Pima cotton are frequently cultivated in the same regions (Hutmacher et al., 

2006). Although cross pollination has been demonstrated between these species, Van Deynze 

and others have found that the isolation distances currently recommended to ensure seed quality 

for Foundation and Registered seed production are adequate to maintain varietal purity 

(Hutmacher et al., 2006; Van Deynze et al., 2005). 

Outcrossing of genes from TwinLinkTM Cotton to G. thurberi is unlikely to occur because G. 

thurberi contains only the D genome whereas G. hirsutum contains both the A and D genome. 

The difference in chromosome numbers precludes sexual compatibility of G. hirsutum with G. 

thurberi (OECD, 2008).

G. tomentosum is native to the Hawaiian Islands (Pleasants and Wendel, 2010). Historic 

literature suggests that differences in flowering patterns and pollinators presented barriers to 

cross pollination between G. tomentosum and either G. hirsutum or G. barbadense (Pleasants and 

Wendel, 2010). Recent field and laboratory studies contradict this historic literature, 

demonstrating that these three species share common pollinators, and further that differences in 

flower structure and flowering habits do not serve as barriers to cross pollination (Pleasants and 

Wendel, 2010). Although laboratory and greenhouse breeding programs with hand pollination 

have produced viable progeny, DNA marker analyses have not found evidence of natural 

hybridization genes between G. hirsutum and G. tomentosum (DeJoode and Wendel, 1992). 

The EPA has established cultivation restrictions on Bt cotton varieties to reduce the possibility of 

gene transfer to feral cotton relatives in Hawaii, Florida, Puerto Rico, and the U.S. Virgin Islands 

(US-EPA, 2008a). The terms and conditions of EPA’s conditional registration for Cry1Ab in 

cotton prohibits commercial cultivation south of Route 60 near Tampa (US-EPA, 2008a). 

TwinLinkTM Cotton is neither expected to be planted commercially in the areas of Florida where 

wild populations of G. hirsutum occur nor would they likely be impacted by TwinLinkTM Cotton

planted north of Route 60. In Hawaii, the EPA (2001b) has restricted the sale and distribution of 

Bt cotton for commercial planting where it could outcross with the wild cotton species G. 

tomentosum. These restrictions in Hawaii also apply to Bt cotton test plots and breeding 

nurseries (US-EPA, 2001b). Because of these restrictions, gene flow from Bt cotton to wild or 

feral populations of G. hirsutum or to G. tomentosum is extremely unlikely. 

APHIS evaluated the potential for gene introgression to occur from TwinLinkTM Cotton to 

sexually compatible wild relatives and considered whether such introgression would result in 

increased weediness. Based on the plant pest risk assessment, APHIS has concluded that 

TwinLinkTM Cotton is not a plant pest and that gene flow between this product and wild or feral 

relatives will not occur in the U.S. (USDA-APHIS, 2010b). 

Based on the above information, APHIS has concluded that that a determination of 

nonregulated status of TwinLinkTM Cotton will not impact sexually compatible relatives, nor 

would it increase the weedy or invasive characteristics of weedy or wild relatives if gene flow or 

introgression were to occur (USDA-APHIS, 2010b). TwinLinkTM Cotton would provide 

growers with an additional cotton variety combining a Bt-based lepidopteran protection, as well 

as herbicide tolerance, and is expected to have the same effect on gene movement as the No 

Action Alternative.
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Based on available scientific evidence, APHIS has not identified any cumulative effects on gene 

movement that would occur from a determination of nonregulated status of TwinLinkTM Cotton. 

Cumulative Effect: Gene Movement

Gene movement between sexually compatible cotton species is no greater for TwinLinkTM 

Cotton than it is for other non-GE or GE cultivars. Many factors limit the likelihood of gene 

movement between cotton species. These include: 

• Cotton is considered to be a self-pollinating crop with a very low frequency of 

outcrossing from insect pollinators or wind;

• The Cry1Ab, Cry2Ae, and bar genes in TwinLinkTM Cotton and other GE cottons impart 

no agronomic advantages whereby a greater potential for weediness or invasiveness 

would result should introgression occur; 

• Neither GE or non-GE cotton cultivars form self-sustaining populations outside of 

cultivation because of limitations in seed dispersal, germination, and high moisture 

requirements (US-EPA, 2001b, 2008a);

• The cotton industry has measures in place to restrict pollen movement and gene flow 

between cotton fields through the use of isolation distances, border and barrier rows, the 

staggering of planting dates and various seed handling, transportation and ginning 

procedures (Sundstrom et al., 2002); and

• Where a potential for GE cotton to introgress into wild or feral populations of cotton

exists, the EPA has placed restrictions on GE cotton breeding, testing, and production 

(US-EPA, 2001b, 2008a). 

In addition, there is no evidence that horizontal gene transfer and expression of DNA occurs 

between cotton and soil bacteria or unrelated plant species under natural field conditions, and 

even if this were to occur, proteins corresponding to the transgenes are not likely to be produced. 

4.5 PUBLIC HEATH

4.5.1 Human Health

Under FFDCA, it is the responsibility of food and feed manufacturers to ensure that the products 

they market are safe and properly labeled. Food and feed derived from TwinLinkTM Cotton

must be in compliance with all applicable legal and regulatory requirements. GE organisms for 

food and feed may undergo a voluntary consultation process with the FDA prior to release 

onto the market. The EPA also has authority over GE crops such as TwinLinkTM Cotton

which present pesticidal properties such as Bt toxin. 

With regard to human health effects, the FDA and the EPA assess the relative toxicity of the 

incorporated proteins on humans from the perspective of both consumption, as well as exposure. 

BCS has submitted a food and feed safety and nutritional assessment to the FDA, as well as 
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a registration review to the EPA for this product. The FDA and EPA are currently reviewing 

the information submitted by the applicant. 

Under the No Action Alternative, TwinLinkTM Cotton would continue as a regulated article. 

Grower and consumer exposure to this product would be limited to those individuals involved 

in the cultivation under regulated conditions. Human exposure to existing traditional and GE 

cotton would not change under this alternative.

No Action: Human Health 

APHIS considers the FDA and the EPA regulatory assessment in making its determination 

of the potential impacts of deregulation of the new agricultural product. BCS has submitted 

a food and feed safety and nutritional assessment to the FDA, as well as a registration 

review to the EPA for this product. The FDA and EPA are currently reviewing the information 

submitted by the applicant. In the absence of these completed agency reviews, APHIS takes into 

consideration prior reviews of comparable products as a starting point for its human health 

impact determination.

Preferred Alternative: Human Health 

Similar products have been deregulated and approved for general cultivation beginning in 1996 

with the introduction of Bt products and followed shortly after by the introduction of the various 

“Liberty” products which provided tolerance to glufosinate ammonium. In each case, FDA and 

EPA reviews and approvals determined that the products met the agency’s review criteria for 

approval. The cultivation of these existing crop products would not change under either 

alternative. Both characteristics have been successfully cultivated in multiple crops in the 

ensuing years with no evidence of human health impacts.

Note that with regard to the expression of glufosinate ammonium tolerance, the gene construct in 

the Bayer TwinLinkTM Cotton is the same as that approved by the FDA in June, 2003 for the 

LibertyLink® Cotton product (US-FDA, 2003). In that approval, the FDA noted that the 

transformational event in LibertyLink®

US-FDA, 

2003

Cotton was not materially different in composition, 

safety, or any other relevant parameter in cotton then grown, marketed, and consumed (

).

The EPA, in 2008, published a Biopesticides Registration Action Document (BRAD) for 

Bacillus thuringiensis (Bt) incorporated protectants (US-EPA, 2008a). Based on a 

comprehensive human health effects assessment, the Bt BRAD found no unreasonable adverse 

effects associated from exposure to the Bt products. The Bt protein is a registered microbial 

pesticide which is approved for use on food crops. The EPA concluded in the BRAD that the Bt 

products incorporated as plant protectants would be expected to behave as expected of a dietary 

protein (US-EPA, 2008a). A tolerance exemption is in place for Cry1Ab protein in all crops (40 

CFR §174.511; US-EPA, 2010d), as well as for the PAT protein (40 CFR §174.522; US-EPA, 

2010g). A temporary exemption from the requirement of a tolerance has been issued for Cry2Ae 

(40 CFR §174.530; US-EPA, 2010e).

For the majority of Bt proteins currently registered, the source bacterium has been a registered 

microbial pesticide, which has been approved for use on food crops without specific restrictions. 
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Because of their use as microbial pesticides, a long history of safe use is associated with many Bt 

products (US-EPA, 2001b). Results from numerous animal and human epidemiological studies 

together, over the years, indicate that biopesticides pose minimal risks to humans and animals

(Betz et al., 2000; US-EPA, 2001b, 2008a). 

The Cry proteins present in the TwinLinkTM Cotton plant have been reviewed and registered by 

the EPA since 1996 and re-registered in 2001 and 2006 (US-EPA, 2001b, 2008a). The EPA has 

determined that the use of these Cry proteins as plant-incorporated protectants do not pose a risk 

to human health (Betz et al., 2000; US-EPA, 2001b, 2008a). 

The PAT protein in TwinLinkTM Cotton is derived from Streptomyces hygroscopius, a common 

soil bacteria. Humans are frequently exposed to this bacteria when consuming vegetables or root 

crops, and there is no evidence of harm from such exposure (Delaney et al., 2008; Hérouet et al., 

2005). APHIS deregulated the PAT enzyme bar gene construct in cotton in 2003 with the BCS 

LibertyLink® Cotton (USDA-APHIS, 2003). In 2003, the FDA completed its food safety 

consultation on LibertyLink®

US-FDA, 

2003

Cotton and granted tolerance exemptions for both the plantincorporated protectant, as well as the genetic material necessary for its production (

). The EPA granted exemptions from the requirement of a tolerance for residues of 

glufosinate ammonium, as well as the plant-pesticide PAT in or on food and feed commodities of 

cotton (see: 62 FR 17719; 40 CFR §180.473; US-EPA, 2010c).

BCS conducted safety evaluations based on Codex Alimentarius Commission procedures to 

assess any potential adverse effects to humans or animals resulting from environmental releases

of TwinLinkTM Cotton containing the Cry1Ab, Cry2Ae, and PAT proteins see (FAO, 2001; 

Scott, 2008). These safety studies included evaluating protein structure and function, including 

homology searches of the amino acid sequences with comparison to all known allergens and 

toxins, an in vitro digestibility assay of the proteins, and an acute toxicity test in the mouse. The

TwinLinkTM Cotton proteins were determined to have no amino acid sequence similar to known 

allergens and lacked toxic potential to mammals (Scott, 2008). The results of studies conducted

by BCS confirm that the crops containing these proteins can be safely used as food or feed

(Scott, 2008). 

The Australia and New Zealand Food Authority (ANZFA) also completed a Toxicological 

Review and Risk Assessment, and a Technical Report was published in 2005 (ANZFA, 2005). 

ANZFA concluded that LibertyLink® Cotton was comparable to non-genetically engineered 

(non-GE) cotton in terms of their safety and nutritional adequacy. In 2004, the Plant Biosafety 

Office (PBO) of the Canadian Food Inspection Agency (CFIA) concluded that BCS’s 

LibertyLink®

CFIA, 2004

Cotton was substantially equivalent to currently grown cotton, in terms of their 

potential environmental impact and livestock feed safety, and the novel traits would not have any 

substantial negative effect on the environment ( ). CFIA further noted that the PAT 

enzyme responsible for glufosinate ammonium tolerance has very specific enzymatic activity 

associated with the acetylation of glufosinate ammonium, and is rapidly inactivated in 

mammalian stomach and intestinal fluids by enzymatic degradation and pH mediated proteolysis 

(CFIA, 2004). 

As with other Bt cotton and herbicide-tolerant cotton products previously deregulated and 

commercialized, including the LibertyLink® variety in 2003, TwinLinkTM Cotton is expected to 
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65

be used throughout cotton producing areas of the country. Based on the analysis of field and 

laboratory data and scientific literature provided by BCS (Scott, 2008), and safety data 

available on other GE cotton, APHIS has concluded that a determination of nonregulated status 

of TwinLinkTM Cotton would have no adverse impacts on human health. Overall impacts are 

similar to the No Action Alternative. 

There are no significant impacts on human or animal health related to the No Action 

Alternative or a determination of nonregulated status of TwinLinkTM Cotton, and no 

cumulative effects have been identified.

Cumulative Effects: Human Health

4.5.2 Worker Safety

EPA’s Worker Protection Standard (WPS) (40 CFR Part 170) was published in 1992 to require 

actions to reduce the risk of pesticide poisonings and injuries among agricultural workers and 

pesticide handlers. The WPS offers protections to more than two and a half million 

agricultural workers who work with pesticides at more than 560,000 workplaces on farms, 

forests, nurseries, and greenhouses. The WPS contains requirements for pesticide safety 

training, notification of pesticide applications, use of personal protective equipment, restricted 

entry intervals following pesticide application, decontamination supplies, and emergency 

medical assistance. 

During agricultural production of cotton, agricultural workers and pesticide applicators may 

be exposed to a variety of EPA registered pesticides (

No Action: Worker Safety 

US-EPA, 2001b). Under the No Action 

Alternative, agricultural workers and pesticide applicators may be exposed to these 

agricultural chemicals during cotton production. Such chemicals would be expected to 

include those products currently used for insect pest and plant pest management in both GE 

and non-GE cotton cultivation.

Before the introduction of Bt cotton varieties in 1996, chemical pesticides were widely used to 

control lepidopteran pests of cotton. Organophosphate, carbamate, and pyrethroid products 

accounted for a substantial percentage of the insecticides used (

Preferred Alternative: Worker Safety

USDA-NASS, 2008). However, 

these three classes of pesticides require numerous safety warnings and extensive use restrictions, 

which raise concerns for worker safety (US-EPA, 2001b). Bt cotton varieties have offered a 

very effective and environmentally benign alternative to chemical insecticides for lepidopteran 

insect pest control. As a result, Bt cotton varieties have been extensively adopted by cotton 

farmers and now represent 73% of the commercial cotton planted (USDA-ERS, 2010a). 

Herbicide-tolerant cotton varieties have seen similar adoption within the industry, with a 78% 

adoption rate in 2010 (USDA-ERS, 2010a). The adoption of herbicide tolerance has allowed 

growers to shift their herbicide use to products like glufosinate ammonium which has a low 

toxicity to humans. Avoidance of other herbicides provides corresponding benefits. 
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66

Similar to the No Action Alternative, it is expected that EPA registered pesticides that are 

currently used for cotton production will continue to be used by growers. If TwinLinkTM Cotton

is adopted, agricultural workers and pesticide applicators may benefit from the use of 

TwinLinkTM Cotton due to a reduction in the use of budworm/bollworm insecticide applications

and the use of the low-toxicity herbicide glufosinate ammonium. The adoption of glufosinate 

ammonium-tolerant cotton allows growers to change cultivation practices in those fields where 

glyphosate resistance has emerged, with the resulting potential reduction in herbicide treatments 

required in those current glyphosate-based systems. A reduction in insecticide and herbicide use 

would benefit worker safety.

A determination of nonregulated status of TwinLinkTM Cotton is not expected to increase the 

total acreage of cotton production or the use of Bt cotton, herbicide-tolerant cotton, or stacked 

varieties presenting both traits. BCS anticipates that TwinLinkTM Cotton will primarily replace 

some of the insect-resistant and herbicide-tolerant cotton cultivars already on the market today. 

As a result, worker safety issues related to the use of EPA registered pesticides during 

conventional and GM cotton production should remain the same. However, if a grower replaces 

a non-Bt cotton or non-herbicide-tolerant cotton variety with TwinLinkTM Cotton, then it would 

be expected that there would be a decrease in the use of lepidopteran pest insecticides. Similarly, 

replacement of herbicide-tolerant cotton currently based on expressing glyphosate tolerance with 

TwinLinkTM Cotton has the potential to reduce herbicide use to manage weedy species which are 

glyphosate-resistant. This has been the case with the adoption of other GM cotton cultivars 

(

Cumulative Effects: Worker Safety 

Benbrook, 2009). A reduction in pesticide use and exposure should positively benefit worker 

safety. 

4.6 ANIMAL FEED

Cotton is grown primarily for its lint, but the seed residue, called cottonseed meal, provides a 

valuable animal feed (Meyer et al., 2007). Cotton seed meal animal feed provides protein, fat, 

and energy (National Cottonseed Products Association, 2002). Under FFDCA, it is the 

responsibility of feed manufacturers to ensure that the products they market are safe and 

properly labeled. Feed derived from TwinLinkTM Cotton must be in compliance with all 

applicable legal and regulatory requirements. GE organisms for feed may undergo a 

voluntary consultation process with the FDA prior to release onto the market. BCS has 

submitted a food and feed safety and nutritional assessment to the FDA, as well as a 

registration review to the EPA for this product. The FDA and EPA are currently reviewing 

the information submitted by the applicant. In the absence of these completed agency 

reviews, APHIS takes into consideration prior reviews of comparable products as a starting 

point for its animal health impact determination.

Under the No Action Alternative, TwinLinkTM Cotton will remain a regulated product and will 

not be available as an animal feed.

No Action: Animal Feed
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67

Cotton-based animal feed will still be available from currently cultivated cotton crops, both 

conventional varieties as well as deregulated GE cotton expressing either insect resistance or 

herbicide tolerance. No change in the availability of the residues of these crops as animal feed 

is expected under this alternative. 

BCS has submitted compositional and nutritional characteristics of TwinLinkTM Cotton seed to 

APHIS (

Preferred Alternative: Animal Feed

Scott, 2008). The nutritional components of TwinLinkTM Cotton were compared with 

the non-transgenic cotton cultivar, Coker 315. The compositional comparison was based on 

analysis of products collected from seven field trials (Scott, 2008). Chemical analysis of the 

cotton samples included the nutritional factors proximate (moisture, crude protein, lipids, ash, 

carbohydrates, and energy); minerals, vitamins, amino acids, and fatty acids (cottonseed oil); and 

the antinutrient factors of cotton including the gossypols, phytic acid, and the cyclic fatty acids

(Scott, 2008). The field trials were conducted to simulate modern cotton cultivation techniques, 

so that the replicates evaluated included fields treated with glufosinate ammonium in accordance 

with the label provisions and untreated fields (Scott, 2008). 

The results provided by BCS show no differences between TwinLinkTM Cotton and the nontransgenic Coker 315 cultivars; reported results for each parameter were also within the 

reference ranges for cotton composition (Scott, 2008). All the analytes measured fell within the 

normal range of natural variation in cotton (ILSI, 2008; OECD, 2004). 

The EPA has established a permanent exemption from the requirement of a tolerance for the 

PAT enzyme and the genetic material necessary for its production in plants (40 CFR 174.522; 

US-EPA, 2010g). A similar permanent exemption has been published for the Cry1Ab protein

in all plants (40 CFR 174.511; US-EPA 2010d). A temporary exemption for the requirement 

of a tolerance for the Cry2Ae protein in cotton has been published at 40 CFR 174.530, in 

accordance with Experimental Use Permit 264-EU-143 (US-EPA, 2010e, 2010f). 

APHIS’s assessment of the safety of this product for animals focuses on plant pest risk (USDAAPHIS, 2010b) and effects on wildlife and threatened and endangered species and those 

analyses are based on the comparison of the GE TwinLinkTM Cotton to its non-GE counterpart. 

No new issues appear to be associated with the Cry and the PAT proteins in TwinLinkTM 

Cotton. 

Based on this information APHIS has concluded that a determination of nonregulated status 

of TwinLinkTM Cotton would have no significant impacts on animal feed or animal health. 

Overall impacts are similar to the No Action Alternative.

There are no significant impacts on animal health related to the No Action Alternative or a 

determination of nonregulated status of TwinLinkTM Cotton, and no cumulative effects have 

been identified. 

Cumulative Effects: Animal Feed
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4.7 SOCIOECONOMIC ISSUES

4.7.1 Domestic Economic Environment at Risk

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). Herbicidetolerant 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, 2010a). 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-APHIS, 

2010a). Bt varieties of cotton offer excellent protection from the damage incurred by insect pests

and an economical alternative to broad-spectrum insecticides. In addition, the adoption of postemergent herbicide-tolerant varieties provide opportunities to apply fewer herbicides and to 

reduce field cultivation (University of California IPM Online, 2009c; USDA-APHIS, 2010a). 

Under the No Action Alternative, TwinLinkTM Cotton would continue to be regulated articles 

under the regulations at 7 CFR Part 340. Growers and other parties who are involved in 

production, handling, processing, or consumption of cotton would not have access to 

TwinLinkTM Cotton, but would continue to have access to existing deregulated GE lepidopteranresistant or herbicide-tolerant (or stacked) cotton varieties as well as other deregulated GE and 

conventional cotton varieties. Domestic growers will continue to utilize currently available 

traditional and GE cotton varieties based upon availability and market demand. Consequently, 

the economic profile of cotton production and marketing is not expected to change.

No Action: Domestic Economic Environment

BCS anticipates that TwinLinkTM Cotton would replace currently available Bt cotton varieties 

and may be selected by growers of conventional cotton varieties making a change to a GE 

variety; however, availability of TwinLinkTM Cotton is not expected to result in an increase in 

cotton acreage (

Preferred Alternative: Domestic Economic Environment

Scott, 2008). BCS considers the major benefits resulting from the introduction 

of TwinLinkTM Cotton and its progeny to be additional grower choice, increased competition, 

and extended useful life of Bt cotton technology.

In its review and analysis of the public interest documents submitted to support current Bt cotton 

products, EPA determined that economic value would result from the sale and use of these 

products (US-EPA, 2001b). Other studies have reached the same conclusions. For example, 

based on an analysis of biotechnology-derived crops planted in 2004, the National Center for 

Food and Agricultural Policy estimated that products providing protection against cotton 

bollworm, tobacco budworm, and pink bollworm increased cotton production by almost 600 

million pounds, improved farm income by almost $300 million, and reduced chemical pesticide 

use by more than 1.6 million pounds (Sankula et al., 2005). In 2006, Fernandez-Cornejo and 

Caswell provided a summary of other studies that characterize effects on yield, pesticide use, and 

grower returns, suggesting that in addition to the economic benefits to the GE developers and 
BAYER TWINLINKTM COTTON

69

seed firms associated with technology fees and seed premiums, both U.S. and foreign consumers 

indirectly benefit through lower commodity prices resulting from increased supplies (FernandezCornejo and Caswell, 2006). Market benefits were estimated at $230 million for herbicidetolerant cotton and $210 million for insect-resistant cotton (Bt cotton) after only two years of 

availability (Fernandez-Cornejo and Caswell, 2006). 

BCS’ field trials demonstrated that TwinLinkTM Cotton was effective in controlling lepidopteran 

larvae, such as cotton bollworm (CBW, Helicoverpa zea), tobacco budworm (TBW, Heliothis 

virenscens) larvae, and fall armyworm (FAW, Spodoptera frugiperda) which are common pests 

of cotton (Scott, 2008). These pests cause severe economic damage to the cotton crop if not 

controlled. If controlled by chemical pesticides, there is the need for large insecticide input 

annually to control these pests (Scott, 2008). The incorporation of the two Bt-based Cry proteins 

obviates the need for the input of these broad spectrum insecticides, with a commensurate 

economic benefit (reduced cost) to the grower. 

Despite the wide adoption of Bt cotton varieties to control lepidopteran insects, these same 

species continue to be the most economically important pests of the crop. In 2009, it was 

estimated that the Heliothine complex of H. virescens and H. zea infested 4.4 million acres of 

cotton and reduced yields across the Cotton Belt by 91,119 bales (Williams, 2010). Total 2009

cost and loss estimates for arthropod cotton pests were $502 million (Williams, 2010).

BCS anticipates that TwinLinkTM Cotton will replace or displace existing GE cotton varieties 

currently in the market. Specific economic projections are not provided. To the extent that the 

planting of TwinLinkTM Cotton results in a decrease in insecticide applications for lepidopteran 

pest control and a potential decrease in herbicide applications where the utilization of glufosinate 

ammonium allows growers to reduce or eliminate multiple herbicides to control glyphosateresistant weeds, farms adopting TwinLinkTM Cotton might experience an increase in net income. 

However, net income differentials cannot be projected. The net income of cotton producers just 

growing Bt cotton varieties or herbicide-tolerant varieties is not available (USDA-NASS, 2007). 

However, as BCS anticipates that TwinLinkTM 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.

Cumulative Effects: Domestic Economic Environment

Based on the information described above, APHIS concludes that a determination of nonregulated status of TwinLinkTM Cotton in itself will have no foreseeable adverse cumulative 

domestic economic effects. TwinLinkTM Cotton would simply replace or displace existing cotton 

varieties for those growers seeking a new combination of insect resistance and herbicide

tolerance. TwinLinkTM Cotton is not expected to lead to an expansion of U.S. cotton acreage. 

No net cumulative effects have been identified associated with a determination of non-regulated 

status and cultivation of TwinLinkTM Cotton. 

4.7.2 Trade Economic Environment at Risk 

Cotton is the single most important textile fiber in the world, accounting for about 40% of all 

fibers produced. On average, the U.S. produces 20% of the global cotton production and is the 
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leading supplier in the international market (Meyer et al., 2007). However, the U.S. cotton 

sector has faced a number of challenges as it shifts from a domestic-oriented market to one 

focused largely on the global marketplace. Domestic mill demand has declined significantly (in 

the U.S.) from only a decade ago as competition from imported textile and apparel products has 

risen dramatically. Meanwhile, export demand has increased rapidly with the recent expansion 

of global textile production (Meyer et al., 2007). The USDA ERS reports that U.S. cotton mills 

consumed 60% of the domestic cotton through the 1990s, but by the mid-2000s 70% of the U.S. 

cotton was exported (Meyer et al., 2007). As a result, U.S. cotton prices are no longer 

determined solely by domestic supplies and stocks (Isengildina-Massa and MacDonald, 2009; 

Meyer et al., 2007).

Research using a multi-region computable general equilibrium model assessed the impacts of 

international Bt cotton adoption on cotton and related sectors of regional economies (Frisvold 

and Reeves, 2007). Productivity gain estimates were based on 2005 adoption rates for Bt cotton 

in seven countries. Global economic benefits were nearly $1.4 billion, with U.S. benefits being 

over $200 million. Increased production from Bt cotton adoption led to a 3% reduction in the 

world cotton price. Employment and trade balances in the textile and apparel sectors increased 

for China and India, but generally declined elsewhere. Individual countries obtained greater 

economic welfare gains upon adoption of Bt cotton; non-adopting regions lost cotton market 

share to adopting regions (Frisvold and Reeves, 2007).

U.S. cotton production reached consecutive records in 2004 and 2005 seasons, with rising global 

cotton demand providing a market for much of the increased output (Meyer et al., 2007). 

However, the growing use of better crop production technologies overseas may narrow the gap 

between foreign production and mill use, constraining growth in foreign import demand and U.S. 

cotton exports (Meyer et al., 2007). Beginning in the 2006 growing year, U.S. cotton acreage 

was considerably lower, as prices favored the planting of alternative crops such as corn and 

soybeans (USDA-ERS, 2009). Increased acreage in cotton in 2010 was attributed to an export 

ban imposed by India early that same year (USDA-FAS, 2010a). Meanwhile, debate over trade 

policy and the sustainability of current farm programs are a source of uncertainty for U.S. 

agricultural commodities in general and the cotton sector in particular (Meyer et al., 2007). 

Around the world, new technology has made cotton more attractive to farmers in many countries, 

and policy reforms in other countries have increased farmers’ willingness to plant cotton 

(USDA-ERS, 2009). Outside the U.S., the spread of Bt cotton has recently revolutionized 

India’s cotton sector as had occurred in China (Meyer et al., 2007). The cost savings of Bt 

cotton brought millions of hectares back into cotton production in eastern China and has also 

helped India’s cotton area rebound by more than 1 million hectares (Meyer et al., 2007). Bt 

cotton has also been adopted in smaller producing countries like Australia, Argentina, Mexico, 

and South Africa (Meyer et al., 2007; USDA-ERS, 2009). 

The cropping and marketing decisions made by cotton growers are unlikely to be influenced by 

the selection of this alternative and it is expected that approximately 93% of the cotton produced 

will continue to be planted with the currently available GE cotton (

No Action: Trade Economic Environment 

USDA-ERS, 2010c). U.S. 

cotton will continue to play a role in global cotton production, and will continue to be a supplier 
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71

in the international market. How and where that cotton will be used will be subject to global 

market conditions.

Global economic benefits from the adoption of Bt cotton were nearly $1.4 billion for the U.S., 

China, India, Australia, Mexico, Argentina, and South Africa (Frisvold and Reeves, 2007). U.S. 

benefits of the use of Bt cotton were over $200 million (Frisvold and Reeves, 2007). The 

adoption of Bt cotton technology has brought millions of hectares of cotton land back into 

production in China and has revolutionized India’s cotton industry (Meyer et al., 2007). 

Economic evidence shows that international trade and productivity is enhanced by the adoption 

of Bt cotton and that these products can be channeled into suitable export markets. 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 TwinLinkTM Cotton remains a 

regulated article. 

BCS intends to submit dossiers to the proper regulatory authorities of foreign governments to 

allow the importation of U.S. cottonseed and to have regulatory processes in place so as to allow 

for the international movement of this product (

Preferred Alternative: Trade Economic Environment 

Scott, 2008). These may include submissions to 

the relevant regulatory authorities in Canada, Mexico, the European Union (EU), and Japan, 

among others. TwinLinkTM Cotton has been, or is currently, in field trials in cotton growing 

regions around the world (Scott, 2008).

A determination of nonregulated status of TwinLinkTM Cotton is not expected to adversely 

impact the trade economic environment and may potentially enhance it through the subsequent 

development and global adoption of the TwinLinkTM Cotton line which could provide another 

lepidopteran insect resistance and herbicide-tolerant management choice for growers. A 

reduction in costs for domestic growers associated with the reduction in insecticide and herbicide 

use may make U.S. producers more competitive in the global market. The trade economic 

impacts associated with the deregulation of TwinLinkTM Cotton are anticipated to be very similar 

to the No Action Alternative.

Current and historic economic evidence indicates that Bt cotton technology enhances 

international cotton trade and production. Based on the information described above, APHIS has 

determined that 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. 

Cumulative Effects: Trade Economic Environment

4.7.3 Social Environment at Risk 

U.S. cotton farms and their operators are similar in many respects to those of other crops, but are 

very different in some key areas. According to data from the 2003 Agricultural Resource 

Management Survey (ARMS), farms growing cotton tend to be larger than those growing other 

crops, with above average gross farm incomes, government payments, farm expenses, net 
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incomes, farm asset values, and debt-to-asset ratios (Meyer et al., 2007).

Large farm operations are more likely to be organized into partnerships, and cotton farms are no 

exception. Partnerships allow operators to pool their resources to achieve economies of scale 

and to combine their talents in managing the farm operation (Meyer et al., 2007). Cotton farm 

operators are also more likely to list farming as their occupation and to have completed high 

school and college compared with other farm operators (Meyer et al., 2007).

Cotton farms in 2003 generated an average net cash income of $127,354 per farm, far more than 

the average of $11,568 for non-cotton farms in the cotton production regions (USDA-ERS, 

2009). The higher average income generated on cotton farms is mainly due to their larger farm 

operations. Cotton farms averaged 1,199 acres per farm, compared with 376 acres for noncotton farms (USDA-ERS, 2009). Cotton farms’ average ratio of cash expenses to gross cash 

income was 71%, compared with 91% for non-cotton farms (USDA-ERS, 2009). This means 

that cotton farms could generate $100 of gross income with less expenditures (i.e., cotton farms 

can earn $100 of gross income for each $71 of cash expense compared to $91 of cash expense 

for a non-cotton farm). Larger farms can achieve economies of scale by spreading management, 

labor, and machinery costs over more units of output, thus gaining an advantage over smaller 

farms (USDA-ERS, 2009).

The household income for cotton producers averaged $142,463 in 2003. In comparison, the 

household income for non-cotton farms in cotton-producing states averaged $71,447 (USDAERS, 2009). For most farm households, income from off-farm sources exceeds income from the 

farm operation. However, cotton producers derive the majority of their family income from the 

farm. Eleven percent of cotton producers listed nonfarm jobs or businesses as their main 

occupation, compared with 48% of non-cotton farm operators (USDA-ERS, 2009).

Under the No Action Alternative, no direct impact on the social environment surrounding cotton 

farming is expected. The cropping and marketing decisions made by cotton growers are 

unlikely to be influenced by the selection of this alternative.

No Action: Social Environment 

Most of the cotton acreage in the U.S. is planted with GE cotton. Of the 11.3 million acres 

planted in cotton in 2010, 93% were GE cotton: 73% of that GE cotton acreage was GE insectresistant (Bt) cotton and 78% was herbicide-tolerant (

Preferred Alternative: Social Environment 

USDA-ERS, 2010a, 2010c). Most cotton 

is planted on farms that have been in cotton production for at least five years (USDA-NASS, 

2007).

The introduced stacked lepidopteran-resistant and herbicide-tolerant trait in TwinLinkTM Cotton

is not intended to confer any competitive advantage in terms of weediness or to extend the range 

of cultivation outside of existing cultivation areas. A determination of nonregulated status of 

TwinLinkTM Cotton by APHIS is not expected to significantly expand the number of cotton 

acres, and cotton acreage is expected to remain relatively stable. Overall impacts are similar to 

the No Action Alternative. 
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Based on the information described above, APHIS has determined that there are no past, present, 

or reasonably foreseeable actions that in aggregate with effects of the proposed action would 

impact the social environment surrounding cotton farming.

Cumulative Effects: Social Environment

4.8 OTHER CUMULATIVE EFFECTS

The potential cumulative effects regarding specific issues have been analyzed and addressed 

above. No further potential cumulative effects have been identified. To date, none of the 

GE cotton varieties that have been deregulated pursuant to Part 340 and the Plant Protection Act 

and used for commercial cotton production or cotton breeding programs have been 

subsequently found to pose a plant pest risk. 

Cultivation of stacked varieties, those crop varieties that may contain more than one trait, 

are currently found in the marketplace and in agricultural production. In the event APHIS 

reaches a determination of nonregulated status, TwinLinkTM Cotton may be combined with 

non-GE and GE cotton varieties by traditional breeding techniques, resulting in a plant that, 

for example, may also be resistant to other herbicides, or may present a different combination 

of insect pest-resistant, but may also have progeny with no transgenes at all. APHIS’ current 

regulations at 7 CFR Part 340 do not provide for Agency oversight of GE cotton varieties 

previously deregulated pursuant to Part 340 and the Plant Protection Act, nor over stacked 

varieties combining deregulated GE varieties unless it can be positively shown that such 

stacked varieties were to pose a likely plant pest risk. 

There is no guarantee that TwinLinkTM Cotton will be stacked with any particular deregulated 

GE variety, as company plans and market demands play a significant role in those business 

decisions. Predicting all potential combinations of stacked varieties that could be created 

using both deregulated GE cotton varieties and also non-GE cotton varieties is hypothetical and 

purely speculative. No further analysis is required. 

4.9 THREATENED AND ENDANGERED SPECIES

The Endangered Species Act (ESA) of 1973, as amended, is one of the most far-reaching 

wildlife conservation laws ever enacted by any nation. Congress, on behalf of the American 

people, passed the ESA to prevent extinctions facing many species of fish, wildlife and 

plants. The purpose of the ESA is to conserve endangered and threatened species and the 

ecosystems on which they depend as key components of America’s heritage. 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 it is determined by the USFWS/NMFS 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;
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• 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, in accordance with the ESA, 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 to discuss factors 

relevant to their effects analysis for petitions for nonregulated status and developed the 

following process for conducting an effects determination for biotechnology regulatory 

actions. Appendix A provides a copy of the interagency consultation protocol.

As part the environmental review process, APHIS thoroughly reviews GE product 

information and data to inform the ESA effects analysis and, if necessary, the biological 

assessment. For each transgene(s)/transgenic plant the following information, data, and 

questions are considered by APHIS: 

• A review of the biology, taxonomy, and weediness potential 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 impact;

• Determination of the concentrations of known plant toxicants (if any are known in 

the plant); and

• Analysis to determine if the transgenic plant is sexually compatible with any 

threatened or endangered plant species (TES) or a host of any TES.

In following this process, APHIS evaluated the potential effects that a determination of 

nonregulated status of TwinLinkTM Cotton would have on Federally listed threatened and 

endangered species (TES) and species proposed for listing, as well as designated critical 

habitat and habitat proposed for designation. Based upon the scope of the EA and 

production areas identified in the Affected Environment section of the EA, APHIS obtained 

a list of TES species (listed and proposed) for each state where cotton is commercially 

produced from the USFWS Environmental Conservation Online System (ECOS; see 

Appendix B). 
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4.9.1 Potential Effects of TwinLinkTM Cotton and Agricultural Practices on TES

BCS anticipates that TwinLinkTM Cotton would replace currently available Bt cotton 

varieties and may be selected by growers of conventional cotton varieties making a change 

to a GE variety; however, availability of TwinLinkTM Cotton is not expected to result in an 

increase in cotton acreage (Scott, 2008). Accordingly, the issues discussed herein focus on 

the potential environmental consequences of the deregulation of TwinLinkTM Cotton on TES 

species in the areas where cotton is grown. 

APHIS therefore focuses its TES review on the implications of exposure to the PAT and Cry 

proteins in cotton. This analysis also addresses the potential impacts of the use of 

glufosinate ammonium, and impacts to non-target organisms and the natural environment. 

BCS has presented data evaluating the agronomic and morphological characteristics of 

TwinLinkTM Cotton, including compositional and nutritional characteristics, safety 

evaluations and toxicity tests, comparing the product to a conventional cotton variety (i.e.,

Coker 315) (Scott, 2008). The results presented by BCS show no differences between 

TwinLinkTM Cotton and the non-transgenic Coker 315 variety, other than the introduced 

PAT and Cry proteins. (See previous discussions on Human Health and Animal Feed for an 

expanded discussion of BCS’ comparison.) 

The agronomic and morphologic characteristics data provided by BCS were used in APHIS 

analysis of the weediness potential for TwinLinkTM Cotton, and evaluated for the potential 

to impact TES. Agronomic studies conducted by BCS tested the hypothesis that the 

weediness potential of TwinLinkTM Cotton is unchanged with respect to conventional cotton 

(Scott, 2008). No differences were detected between TwinLinkTM Cotton and nontransgenic 

cotton in growth, reproduction, or interactions with pests and diseases, other than the 

intended effect of protection from lepidopteran pests. The main natural controls on feral 

populations of cotton are poor seed dispersal, poor seed germination, competition from other 

plants, and a high requirement for moisture (US-EPA, 2001b). Therefore, the incorporation 

of either the insect resistance trait or the herbicide tolerance trait is unlikely to appreciably 

improve seedling establishment and increase weediness potential. Any TwinLinkTM Cotton 

volunteers could be readily controlled by other readily available herbicides, including 

glyphosate (Miller et al., 2004; Stewart et al., 2003). Based on this analysis, APHIS has 

concluded that deregulation of TwinLinkTM Cotton has no potential to affect TES, as a result 

of weediness.

In addition to evaluating BCS’ comparisons of TwinLinkTM Cotton with the non-transgenic 

Coker 315 variety, for potential differences in agronomic and morphology APHIS also 

considers the EPA and FDA regulatory assessment in making its determination of the 

potential impacts of deregulation of the new agricultural product. In that regard, BCS has 

submitted food and feed safety and nutritional assessments to the FDA as well as 

comparable exemptions from tolerance and registration reviews to the EPA for TwinLinkTM 

Cotton. The FDA and EPA are currently reviewing the information submitted by the 

applicant. In the absence of a completed FDA and EPA determinations, APHIS takes into 

consideration prior agency reviews of comparable products to conduct its assessment of the 

potential impacts. As discussed above in Animal and Plant Communities (Subsection 4.4) 
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and Public Health (Subsection 4.5), both agencies have previously reviewed and approved 

comparable products, including several crop varieties expressing the Bt-based Cry proteins 

as plant-incorporated protectants, as well as the bar gene, resulting in the expression of the 

PAT enzyme providing tolerance to glufosinate ammonium. 

Data regarding the environmental safety of PAT proteins have been extensively reviewed in 

international scientific, peer-reviewed journals (Hérouet et al., 2005). In summary, the PAT 

protein is expressed in a number of GM crops that have been approved by regulatory 

agencies. These GM crops have been consumed by humans and animals since 1995 and 

have exhibited no significant adverse effects. The PAT protein mode of action is specific to 

the breakdown of ammonia in plant tissues. Because animals lack this enzymatic pathway 

(Hérouet et al., 2005), and there is no mechanism to transfer this gene to unrelated plant 

species, APHIS limits its analysis of the implications of exposure to the PAT protein to the 

potential for gene movement to related TES cotton species.

None of the relatives of cotton are listed (or proposed) as endangered or threatened species 

under Federal (US-FWS, 2011a) or state listings (Arizona, 2009; Hawaii, 2001) with the 

exception of G. hirsutum in the State of Florida, where wild populations of upland cotton, G. 

hirsutum have been listed as endangered by the state (Coile and Garland, 2003; Institute for 

Regional Conservation, 2010). However, in Florida, wild G. hirsutum is not present in the 

northwestern panhandle where cotton cultivation occurs, and cultivation of cotton is 

prohibited by the EPA in those areas of southern Florida where it is found (Coile and 

Garland, 2003; US-EPA, 2008a; USDA-NASS, 2007; Wunderlin and Hansen, 2010). 

Accordingly, the deregulation of TwinLinkTM Cotton is not expected to impact state 

endangered feral cotton populations.

Evaluation of the potential exposure of threatened and endangered species to the Bt-based 

Cry proteins focuses on the route of exposure. Cry1Ab and Cry2Ae proteins are highly 

specific to Lepidoptera. The specificity of Bt crystalline proteins to lepidopteran insect 

larvae, but not for other insects, birds, and mammals results from the highly specific 

receptors for these proteins in the larvae midgut (Lemaux, 2009). Once activated by insectspecific proteases in the insect midgut, Cry proteins bind to receptors in the midgut. Such 

binding leads to the formation of pores in the midgut membranes and ultimately to cell lysis 

and death. The specific binding of Bt-based Cry proteins to midgut membrane receptors is a 

key determinant of pest specificity (Showalter et al., 2009). Accordingly, the APHIS review 

of the potential impacts is focused on Federally listed threatened and endangered 

lepidopterans in the cotton growing regions of the U.S.

APHIS obtained and reviewed the USFWS Federal List of listed (or proposed) TES and 

considered the potential impacts of a determination of nonregulated status of TwinLinkTM 

Cotton on lepidopterans (Appendix B). There are currently 21 species of butterflies, moths, 

and skippers on this list (US-FWS, 2011b). Because it is not possible to use TES species to 

quantify sensitivity to the Cry and PAT proteins, APHIS’ evaluation focused on the 

likelihood of exposure of TES species to the Bt-endotoxin expressed in TwinLinkTM Cotton. 

Exposure of TES species to the Bt-based Cry proteins in TwinLinkTM Cotton is only likely if 

the species occur in the areas where cotton is grown, as cotton plant parts (seeds, pollen, and 

crop debris) are not readily transported long distances without human involvement. 
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APHIS has thoroughly examined all listed and proposed threatened and endangered 

lepidopterans and compared their habitats to those habitats present in counties where cotton 

is grown. APHIS has determined that the breeding habitats of listed Lepidoptera do not 

overlap cotton growing areas. Therefore, it is highly unlikely that these species can be 

exposed to TwinLinkTM Cotton. Habitats in which threatened and endangered lepidopterans 

in the U.S. are likely to occur are very limited in geographical distribution. Moreover, the 

larvae of these species typically feed on specific host plants, none of which include cotton, 

or plants likely to be found in cotton fields. In those states where cotton is cultivated, 

lepidopteran species on the Federal TES list only occur in California, Florida, and North 

Carolina (US-FWS, 2011b) (see Appendix B: Threatened and Endangered Species). Of 

these species, only the Quino Checkerspot butterfly (Euphydryas editha quino), the Kern 

primrose sphinx moth (Euproserpinus euterpe), and the Saint Francis’ satyr (Neonympha 

mitchellii francisci) are known to occur in counties were cotton is grown. 

The Quino Checkerspot butterfly is found in coastal sage scrub, open chaparral, juniper 

woodland, and native grassland (US-FWS, 2003). Its primary host plants include: the 

dwarf plantain (Plantago erecta) that occurs in southern California within annual scrub, 

grassland, and open chaparral plant communities; the wooly plantain (Plantago patagonica) 

that overlaps in distribution with P. erecta at lower elevations; the white snapdragon 

(Antirrhinum coulterianum) that appears to be a facultative fire-follower in non-desert areas 

and in desert plant communities often growing between shrubs; and the thread-leaved bird’s 

beak (Cordylanthus rigidus), a partially parasitic plant often found at high densities in 

disturbed areas, open slopes, and flats of foothill woodlands, chaparral margins, and 

coniferous forests (US-FWS, 2003). Areas where cotton is grown are likely to have been 

used in agricultural production for many years and thus would not change the habitat that is 

already unsuitable for the Quino Checkerspot butterfly. 

The Kern primrose sphinx moth is also found in California. This moth may occupy habitat 

near cotton cultivation, known to occur in Kern, Santa Barbara, San Luis Obispo, and 

Ventura Counties, CA (Jump et al., 2006; US-FWS, 2007a). The larvae feed primarily on 

their essential host plant Camissonia sp. (certain primrose and sun cup species). The host 

plant evening primrose is found along sandy washes with young alluvial sandy soils that are 

prone to regular flooding (Jump et al., 2006). Since listing, the primary threats to the Kern 

primrose sphinx moth are agricultural land use practices that degrade the moth habitat, 

particularly cattle grazing, disking, pesticide and herbicide use, and development. Many 

agricultural pesticides are specifically designed to target insect larvae (caterpillars) as well 

as adult moths (US-FWS, 2007a). All Kern primrose sphinx moth populations are 

potentially at risk from this effect. Kern primrose sphinx moth exposure to agricultural 

pesticides could occur when cotton is grown in and around sandy washes with sandy alluvial 

soil where moths perform morning basking and where the food plant Camissonia campestris

or C. contorta (field primrose and evening primrose, respectively) is supported. The 

potential route of Kern primrose sphinx moth exposure to the Bt protein contained in 

TwinLinkTM Cotton would be in the form of pollen deposited on the evening primrose, 

where the threatened caterpillars feed. Because cotton pollen is heavy and will not be 

dispersed much from the field (Thies, 1953), it is not likely that the larvae of the Kern 

primrose sphinx moth will be exposed to the Cry protein. Any pollen produced by 

TwinLinkTM Cotton plants is not expected to drift onto larval host plants. 
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The Saint Francis’ satyr is known only in the sand hills of North Carolina, in Cumberland 

and Hoke Counties (US-FWS, 2010a). The species is known only to be located on 

government land (Fort Bragg U.S. Army installation). The habitat occupied by this satyr 

consists primarily of wide, wet meadows dominated by a high diversity of sedges (Carex) 

and other wetland graminoids. Saint Francis’ satyr has also been observed in pitcher plant 

(Sarracenia flava) swales, with cane (Arundinaria tecta), rough-leaved loosestrife 

(Lysimachia asperulaefolia), and pocosin lily (Lilium iridollai). It is unknown whether 

satyr uses such habitat for reproduction or simply as a dispersal corridor. Adult food habits 

are not really known; larva probably feed on Carex, but this has not been established. 

Oviposition has been observed on small Panicum grass. Areas in Hoke and Cumberland 

County where cotton is grown are likely to have been used in agricultural production for 

many years and would be unsuitable habitat for the Saint Francis’ satyr. 

As noted above, the EPA conducts a comprehensive assessment of the implications of 

pesticide registrations on TES. EPA’s evaluations include exposure assessments and 

ecological effects data for each registered pesticide. The EPA (2001b, 2008a) has published 

the following specific statements regarding potential effects of Bt-based Cry proteins 

incorporated in cotton—

...The larvae of endangered Lepidoptera species in cotton growing counties 

(Quino Checkerspot butterfly, Saint Francis' satyr butterfly and Kern primrose 

sphinx moth) are not going to be exposed to Cry1Ac protein [the Bt-based

Cry protein that was the focus of this report] because their habitats do not 

overlap with cotton fields. The Quino Checkerspot butterfly is found only in 

the coastal sage scrub habitat in southern California, the Kern primrose sphinx 

moth (threatened, not endangered) is found only on a privately owned ranch 

in the Walker Basin, Kern County California. Finally, the only known 

population of Saint Francis’ satyr butterfly is found in wetlands dominated by 

sedges and grasses on Department of Defense property in North Carolina. 

None of the larvae of these insects feed on cotton, and will not be exposed to 

Cry protein in pollen. The amount of pollen that would drift from these 

cotton plants onto plants fed upon by endangered/threatened species, would 

be very small (if measurable) compared to the levels fed to the test species. 

Therefore, EPA does not expect that any endangered/threatened species will 

be affected by pollen containing the Cry1Ac protein. 

In addition, because EPA is imposing conditions for geographic areas (Hawaii and Florida) 

that have sexually compatible wild or weedy relatives of cotton, the Cry1Ac protein gene 

cannot escape into related wild plants which could serve as a source of Bt pollen for plants 

on which endangered/threatened species may feed on in these areas. 

Because EPA expects that no listed endangered species of Lepidoptera will be exposed to 

the Bt Cry protein expressed in cotton plants, and because the most probable exposure 

scenario does not appear to affect listed species, EPA believes that this action will have no 

effect on listed species (US-EPA, 2001b; see also US-EPA 2008a).
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Based on the information above, APHIS has determined there would be no effects to the 

three listed lepidopteran species as a result of a determination of nonregulated status of

TwinLinkTM Cotton.

4.9.2 Potential Effects of the Use of Glufosinate Ammonium

As the action agency for pesticide registrations, EPA has the responsibility to conduct an 

assessment of effects of a registration action on endangered species. The EPA Endangered 

Species Protection Program web site, http://www.epa.gov/espp/

When registering a pesticide or reassessing the potential ecological risks from use of a 

currently registered pesticide, EPA evaluates extensive exposure and ecological effects data 

to determine how a pesticide will move through and break down in the environment. Risks 

to birds, fish, invertebrates, mammals, and plants are routinely assessed and used in EPA’s 

determinations of whether a pesticide may be licensed for use in the U.S.

, describes the EPA 

assessment process for endangered species. Some of the elements of that process, generally 

taken from the web site, are summarized below.

EPA’s core pesticide risk assessment and regulatory processes ensure that protections are in 

place for all populations of nontarget species, including TES. These assessments provide 

EPA with information needed to develop label use restrictions for the pesticide. These label 

restrictions carry the weight of law and are enforced by EPA and the states (Federal 

Insecticide, Fungicide, and Rodenticide Act 7 USC 136j (a)(2)(G) Unlawful acts). Because 

TES may need specific protection, EPA has developed risk assessment procedures described 

in the Overview of the Ecological Risk Assessment Process (US-EPA, 2004) to determine 

whether individuals of a listed species have the potential to be harmed by a pesticide, and if 

so, what specific protections may be appropriate. EPA’s conclusion regarding the potential 

risks a pesticide may pose to a listed species and any designated critical habitat for the 

species, after conducting a thorough ecological risk assessment, results in an "effects 

determination" in accordance with Section 7 (a)(2) of the ESA. 

The EPA first registered glufosinate ammonium in 2000 as a non-selective foliar herbicide 

for use on a wide range of crops, including cotton (US-EPA, 2008b). In 2008, the EPA 

announced that it was undertaking a registration review of this product, and has published a 

preliminary work plan for this process (US-EPA, 2008b). The EPS’ preliminary work plan 

provides for an ecological risk assessment (ERA) to allow the EPA 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 (US-EPA, 2008b). If 

the ERA indicates that glufosinate ammonium “may affect” a listed species or its designated

critical habitat, the assessment will be refined to allow the EPA to determine whether the 

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 (US-EPA, 2008b). When an 

ERA 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, as appropriate.
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To mitigate potential adverse effects to TES, EPA has imposed specific label use restrictions 

for glufosinate ammonium use when applied with aerial equipment including “The product 

should only be applied when the potential for drift to adjacent sensitive areas (e.g., 

residential areas, bodies of water, known habitat for threatened or endangered species, nontarget crops) is minimal (e.g., when wind is blowing away from the sensitive areas)” (BCS, 

2010a). 

To facilitate pesticide applicators adherence to EPA label use restrictions for glufosinate 

ammonium, BCS’ label for Ignite, the commercial form of glufosinate ammonium, provides 

specific instructions for managing spray drift and cautions pertaining to applications around 

water so as to minimize potential effects to non-target organisms (BCS, 2010a). Label 

requirements for BCS’ Ignite formulations prohibit application in conditions or locations 

where adverse impact on Federally listed endangered/threatened plants or aquatic species is 

likely (BCS, 2010a). BCS has also provided a technical and trade manual with additional 

guidance on the proper storage, handling and use of the product (BCS, 2010b).

In conclusion, there are legal precautions in place (EPA label use restrictions) and “best 

practice” guidance to reduce the possibility of exposure and adverse impacts to TES from 

glufosinate ammonium application to TwinLinkTM Cotton; EPA has considered potential 

impacts to TES as part of their registration and labeling process for glufosinate ammonium; 

and adherence to EPA label use restrictions by the pesticide applicator will ensure that the 

use of glufosinate ammonium will not adversely affect TES or critical habitat. Based on 

these factors and the legal requirements for pesticide applicators to follow EPA label use 

restrictions, APHIS has determined that the use of EPA registered glufosinate ammonium 

for TwinLinkTM Cotton production will not adversely impact listed species or species 

proposed for listing and would not adversely impact designated critical habitat or habitat 

proposed for designation. 

Based on the above information, APHIS has determined that the Preferred Alternative, a 

determination of nonregulated status of TwinLinkTM Cotton, would have no effect on 

Federally listed TES and species proposed for listing, or on designated critical habitat or 

habitat proposed for designation. Consequently, a written concurrence or formal 

consultation with the USFWS is not required for this action.

4.10 CONSIDERATION OF EXECUTIVE ORDERS, STANDARDS, AND TREATIES 

RELATING TO ENVIRONMENTAL IMPACTS

4.10.1 Executive Orders with Domestic Implications

The following two executive orders require consideration of the potential impacts to minority 

and low income populations and children:

• Executive Order (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 
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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.

Each alternative was 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, along with the history of safe use of microbial Bt products and 

other cotton varieties expressing Bt and PAT proteins, establishes the safety of TwinLinkTM 

Cotton and its 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. 

None of the impacts on agricultural practices expected to be associated with deregulation of 

TwinLinkTM Cotton are expected to have a disproportionate adverse effect on minorities, low 

income populations, or children. As noted above, the cultivation of previously deregulated 

cotton varieties with similar insect-resistant traits has been associated with a decrease and/or 

shift in pesticide applications for those who adopt these varieties that is either favorable or 

neutral with respect to environmental and human toxicity. If pesticide applications are reduced, 

there may be a beneficial effect on children and low income populations that might be exposed to 

the chemicals. These populations might include migrant farm workers and their families, and 

other rural dwelling individuals who are exposed to pesticides through groundwater 

contamination or other means of exposure. It is expected that EPA and USDA Economic 

Research Service would monitor the use of this product to determine impacts on agricultural 

practices, such as chemical use, as they have done previously for other products.

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. 

Non-engineered cotton as well as other Bt and herbicide-tolerant cotton varieties are widely 

grown in the U.S. Based on historical experience with these varieties and the data submitted by 

the applicant and reviewed by APHIS, TwinLinkTM Cotton plants are sufficiently similar in 
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fitness characteristics to other cotton varieties currently grown and are not expected to become 

weedy or invasive (USDA-APHIS, 2010b). 

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. 

Data submitted by the applicant has shown no difference in compositional and nutritional 

quality of TwinLinkTM Cotton compared with other GE cotton or non-GE cotton, apart from the 

presence of the two Cry proteins and the PAT protein. The migratory birds that occasionally 

forage in cotton fields are unlikely to ingest high amounts of TwinLinkTM Cotton seed as cotton 

seed is limited by harvest. 

The introduction of Bt cotton has had a positive effect on bird counts in North American cotton 

fields. Comparing bird populations from 1991 to 1995 and 1996 to 2000, EPA (2001b)

showed that bird counts increased and were positively correlated with Bt cotton adoption, the 

reduction in insecticide use, and the relative presence of the species in cotton fields prior to the 

introduction of Bt cotton (US-EPA, 2001b). Broad-spectrum insecticides, which are considered 

to be one of the largest impediments to agroecosystem biodiversity, have been reduced by the 

commercial use of Bt cotton (Benbrook, 2009; USDA-NASS, 2008). Since the introduction of 

Bt cotton there has been a two thirds decrease in use for the most toxic insecticides products to 

birds and fish, and a comparable one third decrease in use for the most toxic products to humans 

(US-EPA, 2001b). Additionally, there have been no reported adverse effects of Bt cotton on 

non-target insects which can serve as a food source for birds. 

Collectively, the weight of considerable field studies with Bt crops, including Bt cotton, have 

consistently demonstrated that Bt crops have only minor effects, if any, on a large number of 

non-target insect taxa which is very small in comparison to the use of broad-spectrum 

insecticides (Naranjo, 2009a).

The history of safe use of crops expressing the PAT enzyme strongly suggests that TwinLinkTM 

Cotton will not present a risk to birds. APHIS deregulated the PAT enzyme bar gene construct 

in cotton in 2003 with the BCS LibertyLink® Cotton (USDA-APHIS, 2003). In 2003, the FDA 

completed its food safety consultation on LibertyLink®

US-FDA, 2003

Cotton, and granted tolerance exemptions 

for both the plant-incorporated protectant as well as the genetic material necessary for its 

production ( ). The EPA granted exemptions from the requirement of a tolerance 

for residues of glufosinate ammonium as well as the plant-pesticide PAT in or on food and feed 

commodities of cotton (see: 62 FR 17719; 40 CFR §180.473; US-EPA, 2010c). When used in 

accordance with label restrictions, glufosinate ammonium does not present a risk to migratory 

birds.
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Based on APHIS’ assessment of TwinLinkTM Cotton, it is unlikely that a determination of 

nonregulated status of this cotton variety will have a negative effect on migratory bird 

populations.

4.10.2 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. 

APHIS has given this EO carefulconsideration and does not expect a significant environmental 

impact outside the U.S. in the event of a determination of nonregulated status of TwinLinkTM 

Cotton. 

It should be noted that all the existing national and international regulatory authorities, and 

phytosanitary regimes that currently apply to introductions of new cotton cultivars 

internationally apply equally to those covered by an APHIS determination of nonregulated status 

under 7 CFR Part 340. 

Any international trade of TwinLinkTM Cotton subsequent to a determination of nonregulated 

status of the product would be fully subject to national phytosanitary requirements and be in 

accordance with phytosanitary standards developed under the International Plant Protection 

Convention (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 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 biotechnology are being 

addressed in other international forums and through national regulations.

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. 
BAYER TWINLINKTM COTTON

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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 (see the NBII 

listings posted at http://usbiotechreg.nbii.gov/). 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 Organization for Economic Cooperation and Development (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, 2003).

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.

4.10.3 Compliance with Clean Water Act and Clean Air Act

This EA evaluated the changes in cotton production due to the unrestricted use of 

TwinLinkTM Cotton. Cultivation of TwinLinkTM Cotton is not expected to lead to the 

increased production of cotton in U.S. agriculture. 

There is no expected change in water use and quality due to the cultivation of TwinLinkTM 

Cotton compared with current cotton seed and cotton production. Also, there is no expected 

change in air quality associated with the cultivation of TwinLinkTM Cotton.

Based on this review, APHIS concludes that the cultivation of TwinLinkTM Cotton would 

comply with the Clean Water Act and the Clean Air Act.

4.10.4 Impacts on Unique Characteristics of Geographic Areas

A determination of non-regulated status of TwinLinkTM 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. 
BAYER TWINLINKTM COTTON

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The common agricultural practices that would be carried out in the cultivation of TwinLinkTM 

Cotton are not expected to deviate from current practices. The product is expected to be 

deployed on agricultural land currently suitable for production of cotton and replace existing 

varieties, and is not expected to increase the acreage of cotton production. 

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 TwinLinkTM Cotton. This action would not convert land use to 

nonagricultural use and therefore would have no adverse impact on prime farm land. Standard 

agricultural practices for land preparation, planting, irrigation, and harvesting of plants would be 

used on agricultural lands planted to TwinLinkTM Cotton, including the use of EPA registered 

pesticides. The Applicant’s adherence to EPA label use restrictions for all pesticides is expected 

to mitigate potential impacts to the human environment. 

4.10.5 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 TwinLinkTM 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 request; thus, the 

tribes would have control over any potential conflict with cultural resources on tribal properties.

APHIS’ proposed action 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. 

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. Nevertheless, it is expected that this noise would only be 

temporary and short-term. The cultivation of TwinLinkTM Cotton is not expected to change any 

of these agronomic practices that would result in an adverse impact under the NHPA.
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Entomology, 34(5), 1224-1241. 

Wilkinson, K. M., & Elevitch, C. R. (2011). The Overstory #65: Biological Nitrogen Fixation.

Agroforestry Ejournal Retrieved February 24, 2011, from 

http://www.agroforestry.net/overstory/overstory65.html

Wilkinson, M. J., & Ford, C. S. (2007). Estimating the potential for ecological harm from gene 

flow to crop wild relatives. Collection of Biosafety Reviews, 3, 42-63. 

Williams, M. R. (2010). Cotton Insect Loss Estimates - 2009. Paper presented at the 2010 

Beltwide Cotton Conferences, New Orleans, LA.

Wilson, E. O. (1988). Biodiversity. Washington, DC: National Academy Press.

Wood, D., Setubal, J., Kaul, R., Monks, D., Kitajima, J., Okura, V., Zhou, Y., Chen, L., Wood, 

G., Almeida, N., Woo, L., Chen, Y., Paulsen, I., Eisen, J., Karp, P., Bovee, S., Chapman, 

P., Clendenning, J., Deatherage, G., Gillet, W., Grant, C., Kutyavin, T., Levy, R., Li, M., 

McClelland, E., Palmieri, A., Raymond, C., Rouse, G., Saenphimmachak, C., Wu, Z., 

Romero, P., Gordon, D., Zhang, S., Yoo, H., Tao, Y., Biddle, P., Jung, M., Krespan, W., 

Perry, M., Gordon-Kamm, B., Liao, L., Kim, S., Hendrick, C., Zhao, Z., Dolan, M., 

Chumley, F., Tingey, S., Tomb, J., Gordon, M., Olson, M., & Nester, E. (2001). The 

genome of the natural genetic engineer Agrobacterium tumefaciens C58. Science, 

294(5550), 2317-2323. 

Wozniak, C. A. (2002). Gene Flow Assessment for Plant-Incorporated Protectants by the 

Biopesticide and Pollution Prevention Division, U.S. EPA. Paper presented at the 

Scientific Methods Workshop: Ecological and Agronomic Consequences of Gene Flow 

from Transgenic Crops to Wild Relatives, Columbus, Ohio.

Wunderlin, R., & Hansen, B. (2010). Atlas of Florida Vascular Plants Retrieved December 5, 

2010, from http://www.florida.plantatlas.usf.edu/
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6 LIST OF PREPARERS

Biotechnology Regulatory Services

Michael Blanchette 

Senior Environmental Protection 

Specialist 

David Reinhold

Assistant Director, 

Environmental Risk Analysis 

Program 

Kham Vongpaseuth

APHIS Fellow

Patricia Beetham, Ph. D.

Biotechnologist

Avatar Environmental LLC

Michael T. Werner, J.D.

Project Manager

Charles Dobroski

Technical Director/Principal
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APPENDIX A

APHIS THREATENED AND ENDANGERED SPECIES DECISION TREE 

FOR FWS CONSULTATIONS
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APPENDIX A

APHIS THREATENED AND ENDANGERED SPECIES DECISION TREE 

FOR FWS CONSULTATIONS

DECISION TREE ON WHETHER SECTION 7 CONSULTATION WITH FWS IS 

TRIGGERED FOR PETITIONS OF TRANSGENIC PLANTS

This decision tree document is based on the phenotypes (traits) that have been permitted for 

environmental releases under APHIS oversight (for a list of approved notifications and 

environmental releases, visit Information Systems for Biotechnology, at http://isb.vt.edu.) 

APHIS will re-evaluate and update this decision document as it receives new applications for 

environmental releases of new traits that are genetically engineered into plants.

BACKGROUND

For each transgene(s)/transgenic plant the following information, data, and questions will be 

addressed by APHIS, and the EAs on each petition will be publicly available. APHIS review 

will encompass:

• A review of the biology, taxonomy, and weediness potential 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 impact;

• 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 (TES) or a host of any TES.

FDA published a policy in 1992 on foods derived from new plant varieties, including those 

derived from transgenic plants (http://vm.cfsan.fda.gov/~lrd/fr92529b.html and 

http://vm.cfsan.fda.gov/~lrd/consulpr.html). The FDA’s policy requires that genetically 

engineered foods meet the same rigorous safety standards as is required of all other foods. Many 

of the food crops currently being developed using biotechnology do not contain substances that 

are significantly different from those already consumed by human and thus do not require premarket approval. Consistent with its 1992 policy, FDA expects developers to consult with the 

agency on safety and regulatory questions. A list of consultations is available at 

http://vm.cfsan.fda.gov/~lrd/biocon.html. APHIS considers the status and conclusion of the 

FDA consultations in its EAs.
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Below is a description of our review process to whether a consultation with U.S. Fish and 

Wildlife Service is necessary.

If the answer to any of the questions 1-4 below is yes, APHIS will contact FWS to determine if a 

consultation is required:

Is the transgenic plant sexually compatible with a TE plant1

1. Are naturally occurring plant toxins (toxicants) or allelochemicals increased over the 

normal concentration range in parental plant species?

without human intervention?

2. Does the transgene product or its metabolites have any significant similarities to known 

toxins2

3. Will the new phenotype(s) imparted to the transgenic plant allow the plant to be grown or 

employed in new habitats (e.g., outside agro-ecosystem)

?

3

4. Does the pest resistance

. 4

A. The transgene acts only in one or more of the following ways:

gene act by one of the mechanisms listed below? If the answer 

is YES then a consultation with U.S. Fish and Wildlife Service is NOT necessary.

i. As a structural barrier to either the attachment of the pest to the host, to penetration of 

the host by the pest, to the spread of the pest in the host plant (e.g., the production of 

lignin, callose, thickened cuticles);

ii. In the plant by inactivating or resisting toxins or other disease causing substances 

produced by the pest;

iii. By creating a deficiency in the host of a component required for growth of the pest 

(such as with fungi and bacteria);

iv. By initiating, enhancing, or potentiating the endogenous host hypersensitive disease 

resistance response found in the plant;

v. In an indirect manner that does not result in killing or interfering with normal growth, 

development, or behavior of the pest;

 

1 APHIS will provide FWS a draft EA that will address the impacts, if any, of gene movement to the TES plant

2 Via a comparison of the amino acid sequence of the transgene’s protein with those found in the protein databases 

like PIR, Swiss-Prot and HIV amino acid data bases.

3 Such phenotypes might include tolerance to environmental stresses such as drought, salt, frost, aluminum or heavy 

metals.

4 Pest resistance would include any toxin or allelochemical that prevents, destroys, repels or mitigates a pest or 

effects any vertebrate or invertebrate animal, plant, or microorganism.
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B. A pest derived transgene is expressed in the plant to confer resistance to that pest (such 

as with coat protein, replicase, and pathogen virulence genes).

For the biotechnologist:

Depending on the outcome of the decision tree, initial the appropriate decision below and 

incorporate its language into the EA. Retain a hard copy of this decision document in the 

petition’s file.

________ BRS has reviewed the data in accordance with a process mutually agreed upon with 

the U.S. Fish and Wildlife Service to determine when a consultation, as required under Section 7 

of the Endangered Species Act, is needed. APHIS has reached a determination that the release 

following a determination of non-regulated status would have no effects on listed threatened or 

endangered species and consequently, a written concurrence or formal consultation with the Fish 

and Wildlife Service is not required for this EA.

________ BRS has reviewed the data in accordance with a process mutually agreed upon with 

the U.S. Fish and Wildlife Service to determine when a consultation, as required under Section 7 

of the Endangered Species Act, is needed. APHIS reached a determination that the release 

following a determination of non-regulated status is not likely to adversely affect any listed 

threatened or endangered species and consequently obtained written concurrence from the Fish 

and Wildlife Service.

________ BRS has reviewed the data in accordance with a process mutually agreed upon with 

the U.S. Fish and Wildlife Service to determine when a consultation, as required under Section 7 

of the Endangered Species Act, is needed. APHIS reached a determination that the release 

following a determination of non-regulated status is likely to affect adversely one or more listed 

threatened or endangered species and has initiated a formal consultation with the Fish and 

Wildlife Service.
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APPENDIX B

THREATENED AND ENDANGERED SPECIES STATE LISTS
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APPENDIX B

THREATENED AND ENDANGERED SPECIES

Distribution, Habitat, and Food Sources of Threatened and Endangered Lepidoptera (USFWS, 2011b)

Given the specificity of activity of the Cry proteins, species outside the insect order Lepidoptera 

should not be affected (Naranjo, 2009a; Sanvido et al., 2006). APHIS has thoroughly examined 

all FWS threatened and endangered lepidopteran species to determine if there could be possible 

effects from the proteins found in TwinLinkTM Cotton. Threatened and endangered 

lepidopterans in the U.S. have restrictive habitats; and their larvae typically feed on specific host 

plants, none of which includes cotton or its sexually compatible relatives, or plants expected to 

be found in cultivated agricultural land. Furthermore, an examination of county distribution of 

endangered lepidopterans shows that most are not known to occur in counties where cotton is 

grown, with the exception of the Kern primrose sphinx moth, the Quino Checkerspot butterfly 

and the Saint Francis’ satyr butterfly. The EPA (2001b) has already concluded that the habitats 

of these species do not overlap with cotton fields and their larvae do not feed on cotton. Pollen 

dispersal due to wind is considered insignificant because cotton pollen is sticky and heavy (Khan 

and Afzal, 1950; Thies, 1953). The EPA (2001b) has concluded that the amounts of cotton 

pollen that might be deposited on host plants of these species would be negligible, or perhaps 

none at all, and have no impact. If pollen were to deposit on host plants, the amount of pollen 

that would drift from these cotton plants onto plants fed upon by endangered/threatened species, 

would be very small compared to the levels fed to test species (Scott, 2008; US-EPA, 2008; 

USDA-APHIS, 2010b).

Species Description

Butterfly, bay checkerspot

Euphydryas editha bayensis

The Bay checkerspot butterfly (Euphydryas editha bayensis) is restricted to 

serpentine outcrops near San Francisco Bay, in Santa Clara and San Matao, 

CA. The primary constituent elements of the habitat for the bay checkerspot 

are one or more of the following: stands of Plantago erecta, Castilleja 

exserta, or Castilleja densiflora; spring flowers providing nectar; pollinators 

of the bay checkerspot’s food and nectar plants; soils derived from 

serpentinic rock; and space for dispersal between habitable areas 

(NatureServe, 2010a; US-FWS, 2001a).

Butterfly, Behren's silverspot

Speyeria zerene behrensii

Currently inhabits one site in southern Mendocino County, CA. The 

Behren’s silverspot butterfly inhabits coastal prairie habitat that contains 

Viola adunca (early blue violet), the larval host plant, adult nectar sources, 

and adult courtship (NatureServe, 2010b; US-FWS, 2004). 

Butterfly, callippe silverspot

Speyeria callippe callippe

Is found in native grassland and associated habitats in the San Francisco Bay 

area, CA. The females lay their eggs on the dry remains of the larvae 

foodplant, Johnny jump-up (Viola pedunculata), or on the surrounding 

debris (Butterfly Conservation Initiative, 2006c; US-FWS, 2010b). 
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Species Description

Butterfly, El Segundo blue

Euphilotes battoides allyni

Now limited to one 302-acre parcel (owned by the Los Angeles Airport) and 

one 2-acre parcel (owned by the Standard Oil Company of California) in El 

Segundo Dunes, Los Angeles County, CA in sand dunes with its larval and 

adult host plant Eriogonum parvifolium (NatureServe, 2010c; US-FWS, 

2007b). 

Butterfly, Fender's blue

Icaricia icarioides fenderi

Restricted primarily to the Willamette Valley of Oregon, in upland prairies 

in Douglas, Benton, Lane, Linn, Polk, and Yamhill Counties, OR and Lewis 

County, WA. Dry, fescue prairies make up the majority of habitat. Larvae 

feed exclusively on certain lupine, mainly Lupinus sulphereus var. kincaid

occasionally L. laxiflorus and albicauliss (NatureServe, 2010d; US-FWS, 

2000a).

Butterfly, Karner blue

Lycaeides melissa samuelis

Requires the wild lupine (Lupinus perennis) that occurs in Illinois, Indiana, 

Michigan, Minnesota, New Hampshire, New York, Ohio, and Wisconsin to 

deposit eggs for larval food. In eastern New York and New Hampshire, 

habitat typically is in sandplain communities, such as grassy openings 

within very dry, sandy pitch pine/scrub oak barrens. In the Midwest, the 

habitat is also dry and sandy, including oak savanna and jack pine barrens, 

and less often dune communities. Within the overall community remnant 

inhabited by a metapopulation, any patch of foodplant in open to semishaded setting is likely to be used. Females lay eggs on or near wild lupine 

plants, and main requirement seems to be thousands of stems of lupine in 

the short term (NatureServe, 2010e).

Butterfly, Lange's metalmark

Apodemia mormo langei

Is currently found only at Antioch Sand Dunes in Contra Costa County, CA, 

as part of the Antioch Dunes National Wildlife Refuge. The larvae are 

known to feed only on buckwheat (Eriogonum nudum ssp. auriculatum) 

(US-FWS, 2008).

Butterfly, lotis blue

Lycaeides argyrognomon lotis

Is found only in Mendocino County, CA in a sphagnum-willow bog of 

about five acres in size. Larvae probably feed on Lotus formosissimus; if 

not then presumably some other legume such as Lathyrus vestitus bolanderi. 

If not a legume, some species of Ericaceae would seem most likely. 

(NatureServe, 2010f). 

Butterfly, mission blue

Icaricia icarioides missionensis

Restricted to a few sites in about three populations, including San Bruno 

Mountain in San Mateo County, Twin Peaks in San Francisco, and the 

vicinity of Skyline College in San Mateo County, CA. Limited to 

grasslands, with its larval hosts, Lupinus albifrons, L. varicolor, and L. 

formosus (NatureServe, 2010g).

Butterfly, Mitchell's satyr

Neonympha mitchellii mitchellii

Known to occur in Indiana, Michigan, and Ohio in northern limestone 

wetlands. Females oviposit on a variety of small forbs and sedges (e.g., 

Thelypeteris palustris, and Carex sp.) seedlings and individuals do not move 

great distances (Barton and Bach, 2005; Szymanski et al., 2004; US-FWS, 

1998a, 2010c).
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Species Description

Butterfly, Myrtle's silverspot

Speyeria zerene myrtleae

Marin, San Mateo, and Sonoma, CA. Myrtle’s silverspot inhabits coastal 

dunes, coastal prairie, and coastal scrub at elevations ranging from sea level 

to 300 meters (1,000 feet), and as far as 5 kilometers (3 miles) inland. The 

larval food plant is Viola adunca and possibly other Viola species (USFWS, 1998b). 

Butterfly, Oregon silverspot

Speyeria zerene hippolyta

Known to occur in Del Norte County, CA; in Clatsop, Lane, Lincoln, 

Tillamook and Counties, OR and Pacific County, WA in salt-spray 

meadows with its host Viola adunca (US-FWS, 2001b).

Butterfly, Palos Verdes blue

Glaucopsyche lygdamus 

palosverdesensis

Occurs only in Los Angeles County, CA, confined to coastal sage scrub 

community and is dependent on two known host plants, locoweed 

(Astragalus trichopodus var. lonchus, also known as Santa Barbara 

milkvetch) and common deerweed (Lotus scoparius) (Butterfly 

Conservation Initiative, 2006a; US-FWS, 1980). 

Butterfly, Quino checkerspot

Euphydryas editha quino (=E. e. 

wrighti)

Is known to occur in the San Diego National Wildlife Refuge, in Riverside 

and San Diego Counties, CA, in Chaparral, coastal sage scrub, with primary 

host plants: dwarf plantain (Plantago erecta), wooly plantain (Plantago 

patagonica), the white snapdragon (Antirrhinum coulterianum), threadleaved bird’s beak (Cordylanthus rigidus) (US-FWS, 2003, 2010d).

Butterfly, Saint Francis' satyr

Neonympha mitchellii francisci

Located in one site in NC sandhills, may be restricted to artillery impact 

areas at Fort Bragg, military installation in North Carolina. Known only 

from a few sedge wetlands (NatureServe, 2010h).

Butterfly, San Bruno elfin

Callophrys mossii bayensis 

Restricted to Contra Costa, Marin and San Mateo Counties, CA. The San 

Bruno elfin is found in coastal mountains near San Francisco Bay, in the 

fog-belt of steep north facing slopes that receive little direct sunlight. It 

lives near prolific growths of the larval food plant, stonecrop (Sedum 

spathulifolium), which is a low-growing succulent. Stonecrop is associated 

with rocky outcrops that occur at 900-1075 feet elevation (Butterfly 

Conservation Initiative, 2006b; NatureServe, 2010i; US-FWS, 2010e). 

Butterfly, Schaus swallowtail

Heraclides aristodemus ponceanus

Restricted to Dade and Monroe Counties, FL. Habitat is tropical hardwood 

hammocks and their edges with the larval foodplant which is torchwood 

Amyris elemifera. Adults do stray into other nearby areas. Larvae feed 

mainly on Amyris elemifera and occasionally on other Rutaceae 

(NatureServe, 2010j; US-FWS, 1999). 

Butterfly, Smith's blue

Euphilotes enoptes smithi

Restricted to Monterey, Santa Cruz, and San Mateo counties, CA. Coastal 

and inland sand dunes and steep slopes along the coast where coastal sand 

dune strand vegetation dominates. One population found in chaparralwoodland dominated area. Also has been found in serpentine grassland 

area. Area must contain seacliff and coastal buckwheat. An undescribed 

ecotype of E. latifolium (coastal buckwheat) is used by the females for 

oviposition as well as providing food for the larvae (NatureServe, 2010k). 
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Species Description

Butterfly, Uncompahgre fritillary

Boloria acrocnema

Restricted to: Gunnison, Hinsdale, and Chaffee counties in CO; isolated 

alpine habitats in the San Juan Mountains of southwestern Colorado. 

Habitat is moist alpine slopes above 12,000 feet with extensive snow willow 

(Salix nivalis) (NatureServe, 2010l; US-FWS, 1994).

Moth, Blackburn's sphinx

Manduca blackburni

, Maui and is more or less restricted 

to tracts of dry forest. Inhabits mostly lowland dry forests and shrub lands 

where the larvae feed on native and a few introduced Solanaceae (tobacco 

family). However, adults do wander and larvae have turned up on cultivated 

Solanaceae. Larvae of Blackburn's sphinx moth feed on plants in the 

nightshade family (Solanaceae). The natural host plants are native shrubs in 

the genus Solanum (popolo), and the native tree, Nothocestrum latifolium

(`aiea), on which the larvae consume leaves, stems, flowers, and buds. 

However, many of the host plants recorded for this species are not native to 

the Hawaiian Islands, and include Nicotiana tabacum (commercial tobacco), 

Nicotiana glauca (tree tobacco), Solanum melongena (eggplant), 

Lycopersicon esculentum (tomato), and possibly Datura stramonium

(Jimson weed) (NatureServe, 2010m; US-FWS, 2000b, 2010f). 

Moth, Kern primrose sphinx

Euproserpinus euterpe

Found in Kern, San Luis Obispo, Santa Barbara, and Ventura Counties, CA. 

The most important habitat factor is presence of the larval foodplant, which 

is Camissonia sp. Some of the habitat has been disked, and some roads and 

development are within the population areas. Sheep grazing has contributed 

to habitat destruction (US-FWS, 2007a). 

BIBLIOGRAPHY

Barton, B. J., & Bach, C. E. (2005). Habitat use by the federally endangered Mitchell's Satyr 

butterfly (Neonympha mitchellii mitchellii) in a Michigan prairie fen. The American 

Midland Naturalist, 153(1), 41-51. 

Butterfly Conservation Initiative. (2006a). Palos Verdes Blue Butterfly Retrieved January 31, 

2011, from http://www.butterflyrecovery.org/species_profiles/profiles.php?id=13

Butterfly Conservation Initiative. (2006b). San Bruno Elfin Butterfly Retrieved January 31, 

2011, from http://www.butterflyrecovery.org/species_profiles/profiles.php?id=16

Butterfly Conservation Initiative. (2006c). Callippe Silverspot Butterfly Retrieved March 8, 

2011, from http://www.butterflyrecovery.org/species_profiles/profiles.php?id=2

Khan, A. H., & Afzal, M. (1950). Natural crossing in cotton in Western Punjab IV. Agents of 

natural crossing. Agronomy Journal, 42(5), 236-238. 

Naranjo, S. E. (2009a). Impacts of Bt crops on non-target invertebrates and insecticide use 

patterns. CAB Review: Perspectives in Agriculture, Veterinary Science, Nutrition and 

Natural Resources, 4(11), 1-23. 

NatureServe. (2010a). Euphydryas editha bayensis: Bay Region Checkerspot Retrieved January 

31, 2011, from 

http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Euphydryas+edit

ha+bay
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NatureServe. (2010b). Speyeria zerene behrensii: Behren's Fritillary Retrieved January 31, 

2011, from 

http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Speyeria+zerene

+behren

NatureServe. (2010c). Euphilotes battoides allyni: El Segundo Blue Retrieved January 31, 2011, 

from 

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des+all

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from 

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s+fend

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a+sam

NatureServe. (2010f). Plebejus anna lotis: Lotis Blue Retrieved January 31, 2011, from 

http://www.fws.gov/sacramento/es/animal_spp_acct/langes_metalmark_butterfly.pdf

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s+missi

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2011, from 

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chellii+francisci

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ii+bayensis

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31, 2011, from 

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demus+ponceanus

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from 

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es+smithi

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31, 2011, from 

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ma

NatureServe. (2010m). Manduca blackburni: Blackburn's Sphinx Moth Retrieved January 31, 

2011, from 

http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Manduca+blackb

urni
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Sanvido, O., Stark, M., Romeis, J., & Bigler, F. (2006). Ecological Impacts of Genetically 

Modified Crops: Experiences from Ten Years of Experimental Field Research and 

Commercial Cultivation. Zürich, Switzerland: Agroscope Reckenholz-Tänikon Research 

Station ART.

Scott, A. L. (2008). Petition for Determination of Nonregulated Status for Insect-Resistant and 

Glufosinate Ammonium-Tolerant Cotton: TwinLinkTM Cotton (Events T304-40 x 

GHB119). Research Triangle Park, NC: Bayer CropScience.

Szymanski, J., Shuey, J. A., & Oberhauser, K. (2004). Population structure of the endangered 

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The American Midland Naturalist, 152(2), 304-322. 

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Journal, 45, 481-484. 

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Registration Action Document Retrieved January 22, 2010, from 

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US-EPA. (2008). Biopesticides Registration Action Document (Bacillus thuringiensis Cry2Ab2 

Protein and its Genetic Material Necessary for its Production in Cotton) (Chemical PC 

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Programs.

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Species with Critical Habitat. Federal Register, 45(129), 44939-44942. 

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Fish and Wildlife Service.

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French (pp. 71). Fort Snelling, MN: U.S. Department of the Interior, Fish and Wildlife 

Service.

US-FWS. (1998b). Seven Coastal Plants and the Myrtle's Silverspot Butterfly Recovery Plan 

(pp. 141). Portland, OR: U.S. Fish and Wildlife Service.

US-FWS. (1999). Schaus Swallowtail Butterfly Heraclides aristodemus ponceanus Mult-Species 

Recovery Plan for South Florida: Invertebrates (pp. 743-766): U.S. Fish and Wildlife 

Service.

US-FWS. (2000a). 50 CFR Part 17 Endangered and Threatened Wildlife and Plants; Endangered 

Status for "Erigeron decumbens" var. "decumbens" (Williamette Daisy) and Fender's 

Blue Butterfly ("Icaricia icarioides fenderi") and Threatened Status for "Lupinus 

sulphureus" ssp. "kincaidii" (Kincaid's Lupine). Federal Register, 65(16), 3875-3890. 

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Determination of Endangered Status for Blackburn's Sphinx Moth from the Hawaiian 

Islands. Federal Register, 65(21), 4770-4779. 

US-FWS. (2001a). 50 CFR Part 17 Endangered and Threatened Wildlife and Plants; Final 

Determination of Critical Habitat for the Bay Checkerspot Butterfly (Euphydryas editha 

bayensis); Final Rule. Federal Register, 66(83), 21450-21489. 

US-FWS. (2001b). Oregon Silverspot Butterfly (Speyeria zerene hippolyta) Revised Recovery 

Plan (pp. 113). Portland, OR: U.S. Fish and Wildlife Service.

US-FWS. (2003). Recovery Plan for the Quino Checkerspot Butterfly (Euphydryas editha quino) 

(pp. 179). Portland, OR: U.S. Fish and Wildlife Service.
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B-7

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