### USDA Notifications and States Approved for Environmental Appendix 1. Releases of DAS

- 40278

- 9 c orn, DAS

- 68416

- 4 soybean, and DAS

- 44406

- 6 s oybean

Page 1

- 1USDA Notification

Number Notification Authorization Date Notification Expiration Date State(s)

09

- 086

- 105n 4/20/2009 4/20/2010 IL, IN, IA, MN, MO, NE, WI

09

- 090

- 107n 4/21/2009 4/21/2010 CA, GA, IL, IA, IN, KS, MI, MN, MO, OH, NE, NJ, OK, PA, TX

09

- 075

- 106n 3/26/2009 3/26/2010 HI, IA, IL, IN, MN, NE, NE, SD, WI

09

- 061

- 005n 4/6/2009 4/6/2010 IA, MN, MS, NY, OH

09

- 005

- 107n 1/15/2009 1/15/2010 HI, IL, IN, IA, NE, PR

08

- 259

- 103n 10/15/2008 10/15/2009 HI

08

- 133

- 107n 6/1/2008 6/1/2009 IL (1), TX (1)

08

- 021

- 110n 4/1/2008 4/1/2009 IA

08

- 021

- 104n 3/20/2008 3/20/2009 IL (7), IN (11), IA (6), MN (4), MS (1), NE (4), WI (3)

07

- 242

- 103n 10/15/2007 10/15/2008 HI

06

- 338

- 101n 1/29/2007 1/29/2008 HI

05

- 308

- 03n 12/13/2005 12/13/2006 HI Table 1

- 1

. USDA Notifications and States Approved for Environ mental Releases of DAS

40278

- 9 c orn

Page 1

- 2Table 1

- 2

. USDA Notifications and States Approved for Environ mental Releases of DAS

68416

- 4 s oybean

USDA Notification

Number Notification Authorization Date Notification Expiration Date State(s)

09

- 259

- 105n 9/25/2009 9/25/2010 PR

09

- 086

- 101n 5/30/2009 5/30/2010 IL, IN, IA, MN, MO, NE, WI

09

- 084

- 110n 4/15/2009 4/15/2010 AL, AR, CA, GA, IL, IN, IA, MI, MN, MO, MS, NE, OH

09

- 075

- 105n 4/15/2009 4/15/2010 HI, IN, IA, PR

09

- 068

- 101n 4/13/2009 4/13/2010 AR, IL, IN, IA, MD, MI, MO, ND, NE, OH, PR, WI

09

- 061

- 104n 4/6/2009 4/6/2010 AR, IL, IN, IA, MN, MS, NY, OH, TN

09

- 005

- 108n 1/1/2009 1/1/2010 HI

08

- 323

- 102n 12/3/2008 12/3/2009 PR

08

- 254

- 110n 9/26/2008 9/26/2009 PR

08

- 170

- 103n 6/26/2008 6/26/2009 MO

08

- 137

- 103n 6/5/2008 6/5/2009 MD

08

- 121

- 103n 5/14/2008 5/14/2009 IA

08

- 121

- 102n 5/15/2008 5/15/2009 IL, IN, MO, NE, OH

08

- 071

- 107n 4/14/2008 4/14/2009 CA, IL, IN, IA, MN, MN, NE

07

- 242

- 107n 9/30/2007 9/30/2008 PR

06

- 292

- 105n 12/1/2006 12/1/2007 IN

Page 1

- 3USDA Notification Number Notification Authorization Date Notification Expiration Date State(s)

11

- 095

- 105n 4/29/2011 4/29/2012 MS

11

- 087

- 114n 4/20/2011 4/20/2012 AL, AR, GA, IL, IN, MD, NE

11

- 067

- 105n 3/30/2011 3/30/2012 AR, CA, IA, IN, IL, LA, MN, MO, MS, OH, WI

10

- 243

- 104n 9/30/2010 9/30/2011 PR

10

- 085

- 103n 4/19/2010 4/19/2011 GA, IA, IN,IL, MI, MO, NE

10

- 083

- 105n 4/22/2010 4/22/2011 IA, IN, MO,MS

10

- 077

- 107n 4/14/2010 4/14/2011 GA, IA, IN,IL, MD, MO,NE, OH, PR

09

- 259

- 108n 10/5/2009 10/5/2010 PR

09

- 068

- 103n 4/1/2009 4/1/2010 IN, PR

08

- 254

- 109n 9/30/2008 9/30/2009 PR Table 1

- 3

. USDA Notifications and States Approved for Environmental Releases of DAS

44406

- 6 s oybean

1 Pending reports as of June 21, 2011 to be submitted within six months of the notification expiration date.

Page 1

- 4

### Summary of Public Comments Appendix 2.

Page 2

- 1Public Scoping Comments
Members of the public were invited to participate in the scoping process for this draft EIS through an announcement of a N otice of I ntent (NOI) to prepare an E nvironmental I mpact S tatement (EIS) in connection with making a determination on the status of DowAgrosciences (DAS) petitions 09

- 233

- 01p (event DAS

- 40278

- 9 corn), 09

- 349

- 01p (event DAS

- 68416

- 4 soybean), and 11

- 234

- 01p (event DAS

- 44406

- 6 soybean). APHIS published a NOI to pre pare an EIS for the three petitions and requested public comments for scoping the EIS in the Federal Register on May 16, 2013. The 60

- day public comment period closed on July 17, 2013. The docket file was published
at http://www.regulations.gov/#!docketDetail;D=APHIS

- 2013

- 0042

. In this NOI, APHIS asked for comments, data, and information regarding 18 broad, overlapping issues. APHIS also requested the public to provide sugges tions for other issues to be discussed or alternatives to be analyzed in the draft EIS. During this comment period, APHIS received 41
comments (see summary in Table 2

- 1) with an additional 9 comments from the virtual public meetings (see summary in Table 2

- 2) . Comments were made by interest groups, industry representatives, industry trade organizations, growers , private individuals, scientists, agronomists and crop specialists, and a Federal agency

. Full text of the comments received during the open

comm ent period is available online at www.regulations.gov.

In addition to post ing written comments directly to the docket, members of the public were given opportunities to provide their comments directly to APHIS during public meetings held on June 26 and 27

, 2013

. Transcripts of the public meetings are available as follows:

For the June 26, 2013 , virtual meeting:

http://www.aphis.usda.gov/biotechnology/downl oads/VPM/062613/VPM_062613_transcript.pdf

For June 27, 2013 , virtual meeting:

http://www.aphis.usda.gov/biotechnology/downloads/VPM/062713/VPM_062713_transcript.pdf

In all, a total of 50 public comments were received with 41 public comment s submitted to the docket folder on the NOI for the preparation of an EIS on 2,4

- D

- resistant c orn and soybean and a n additional 9 comments were given on the NOI during the virtual meetings.

APHIS used the public comments to identify issues to be considered in development of the Draft EIS. A number of commenters indicated they object to APHIS NOI to prepare an EIS , finding the level of analysis performed in the EAs scientifically sufficient. These commenters felt preparing an EIS unnecessarily keeps valuable traits and tools currently needed by growers battling herbicide

- resistant weeds.

Overal l, t he comments submitted echoed the issues previously raised in the public comments made on the petitions and/or draft EAs for the three events. Most of the comments continued to voice concern over the potential increased use of 2,4

- D by growers with ado ption of the three deregulated events. While APHIS recognizes these concerns, APHIS does not regulate pesticide use. EPA is reviewing and analyzing the information DAS has submitted in support of the registration of their new 2,4

- D choline salt formulati on. This includes assessing the physical and
Page 2

- 2chemical properties of, fate and transport of, and impacts to the environment and human health from the new formulation. APHIS has no input into the decision of permitting the use of the new 2,4

- D formulation; therefore, those issues are not analyzed in this EIS.

The public comments on the NOI, the two draft EAs, and the petitions were grouped into several main themes. Below is a summary of the issues identified in the public scoping comments.

1. Alternatives

• C onsider an alternative involving mandatory weed resistance management.

• Provide an assessment of Integrated Weed Management (IWM) systems or non

- chemical tactics as an alternative to deregulation of DAS

‐ 68416

- 4 soybean for the stated purpose of Dow’s produ ct, to provide a means to control glyphosate

- resistant weeds

• The statement of purpose and need is missing from the notices. To what need and for what purposes are petitioners responding in developing and commercializing their products? The answer to this question largely determines the range of reasonable alternatives the agency must consider in the NEPA process.

• Granting (with or without conditions) or denying petitions does not constitute “alternatives” to be considered in NEPA’s environmental impact statement process; rather, they are decision options for the agency (see my earlier comment for explanation). Alternatives that must be considered under NEPA relate directly to the purposes of and need for proposed actions.

2. Inserted Genes/Plant Compositi on

• Degree of resistance conferred by the transgene in different plant parts and stages of development.

• APHIS did not take into account the potential toxicity of DAS

- 40278

- 9 corn, DAS

- 68416

- 4 soybean, and DAS

- 44406

- 6 soybean to listed species that might eat leaves, roots, stems, or flower parts. Migrating birds, for example, eat parts of the soybean plant. Bees consume the pollen and nectar, and presumably other insects do as well. Soybean detritus washes into wetlands.

• APHI S should initiate consultations with FWS and NMFS concerning the approval of DAS

- 40278

- 9 corn, DAS

- 68416

- 4 soybean, and DAS

- 44406

- 6 soybean

.
• Assess the characteristics of DAS

- 40278

- 9 corn conferred by the activity of the novel enzyme AAD

- 1 and potential im pacts.

• Analyze composition of the AAD

- 1 protein in the crop after exposure of DAS

- 40278

- 9 corn to 2,4

- D or quizalofop.

• Perform additional research and information regarding any impacts to the nutritive value of DAS

- 68416

- 4 soybean compared to non

- GE soybea n. The commenter stated that the U.S. Food and Drug Administration (FDA) noted several differences in the compositional analysis of DAS soybean. Although the FDA recognized DAS

- 68416

- 4 Soybean as safe, the commenter requested a description of the differe nces, including supporting data, to confirm the DAS soybean is as safe as conventional soybean varieties. The commenter also requested additional research beyond the initial 15

- day study to determine the safety of the

Page 2

- 3AAD

- 12 protein to confirm the nutritio nal differences would not affect human or animal health.

• More research must be done to show that these nutritional differences do not result in any functional differences that could affect human or animal health when this corn is present in food or animal feed.

• Information on the degree of resistance conferred by the transgene in different plant parts and stages of development should be available for review by APHIS and the public.

• Information on the expression of the transgene in pollen, nectar , and levels of herbicide residues

. M etabolites in pollen and nectar should be available for review by APHIS and the public.

3. Miscellaneous

• Prove the deregulation will neither jeopardize any species nor harm any critical habitat anywhere the crop system may be grown.

• The conversion of natural areas and Conservation Reserve Program lands to corn production and the resultant increase in herbicide use would result in adverse impacts to listed threatened and endangered species, because these areas have not been previousl y farmed and are likely to support native species.

• Tillage can greatly reduce selection pressure on herbicides and thus aid in prevention of herbicide resistance. Tillage can also aid in management of resistant weeds once they become a problem. Tillage, ho wever, is not an option in most cases. Our growers have worked hard to make no

- till a success on their farms. They adopted no

- till partly because of conservation compliance requirements in the past several farm bills. But regardless of conservation complia nce, the major driving force was economics. Savings in fuel, labor, and equipment through no

- till production helped growers remain competitive. A return to tillage would be a step backwards in terms of productivity and environmental protection. Moreover, g rowers simply do not have the labor and equipment to go back to tillage.

• Address the cumulative impact of seed market concentration. The seed market concentration impacts of a deregulation of 2,4

- D resistant corn constitute a significant intertwined socioe conomic impact that is reasonably foreseeable.

• Assess economic impact of the higher cost of 2,4

- D resistant corn to farmers.

• APHIS should find or develop studies that explore the extent to which pricing strategies for HR crop systems (e.g. high

- priced seed, low

- cost herbicide) reinforce herbicide use patterns that foster resistance in the case of 2,4

- D

- resistant corn and soybean s.

• Consider the possible impacts that yet another genetic trait can have on farmers in Mexico and around the world where native maize and wild corn relatives are not only grown, but an indispensable part of their culture and the economy.

• Conduct a larger analysis of domestic socioeconomic impacts given that biotech soybeans are more costly than non

- biotech seeds and would increase costs for farmers.

• Herbicide tolerant crops have made the no

- till system much more timely and cost effective for our operation . The no

- till system is so effective at controlling erosion in our area that if we had to go back to tillage to control resistant weeds, the long

- term cost would be very high in soil loss alone.

• Biotechnology has allowed plant breeders to develop soybeans that are tolerant to herbicides, thus allowing soybean farmers to better control weeds and implement no

- till
Page 2

- 4and conservation tillage practices that save fuel, reduce erosion, and protect the environment.

• APHIS must assess 2,4

- D

- resistant corn and soybean s as crop systems comprising the herbicide

- resistant crop itself and associated use of 2,4

- D.

• APHIS should examine both short

- term and long

- term impacts of the proposed herbicide

resistant crop systems in the light of what has been learned from real

- world experiences with previously

- approved herbicide

- resistant crop systems. What are the likely similarities and differences in terms of environmental health and economic concerns?

• APHIS has often claimed that, although individual farmers may be affected by rel easing genetically engineered organisms in the area, when examined in total, none of the potential business losses is expected to be so severe as to amount to a significant impact. This determination fails to recognize that environmental “significance” ex ists at all levels―“society as a whole (human, national), the affected region, the affected interests, and the locality.”

• The USDA’s Environmental Impact Statement must include, at a minimum research on how the ingestion of foods manufactured from these crops will affect human health and how the continued use of the herbicide in agriculture could endanger agricultural workers and the general public.

• Thus, 92% of Georgia cotton growers hand

- weed 52% of the crop with an average cost of $23 per hand

- weeded a cre, which is an increase of at least 475% as compared to hand weeding costs prior to resistance. In addition to increased herbicide use and hand weeding, growers in Georgia have indicated that they are using mechanical, in

- crop cultivation (44% of acres), tillage for the incorporation of pre

- plant herbicides (20% of the acres), and deep turning (19% of the acres every three years) to aid in Palmer amaranth control. Current weed management systems are extremely diverse, complex, less environmentally friendl y, and costly when compared to those systems employed only a decade ago. Growers are in desperate need of new technologies that will aid in the management of glyphosate

- resistant Palmer amaranth, and other problematic weeds, for long term sustainability.

• T he introduction of soybeans tolerant to 2,4

- D will allow an additional mode of action to be used in the system, allowing for better weed control and harvested soybeans with less foreign material from weed seeds, a valuable characteristic for processors.

• APHIS should assess the socioeconomic consequences of 2,4

- D

- resistant corn and soybeans, in terms of increased land and rental prices from increased competition for land, increased average size of farms, and accelerated exit of small

- to medium

- size farmer s from agriculture.

4. Herbicide

- Resistant Weeds

• Provide analysis of the prevalence /emergence of glyphosate

‐ resistant weeds.

• Weed resistance is a well understood scientific phenomenon that is not unique to biotechnology or any other form of agriculture. Dif ferent herbicides attack weeds by different methods or “modes of action.”

• Overuse of any herbicide technology leads to selection pressure for development of resistance to that technology. Resistance to other herbicides was problematic previously and thus will continue to present management problems for growers in terms of herbicide

Page 2

- 5alternatives that remain as effective options. New cases of weed resistance will evolve in response to current soybean weed management programs.

• Science has clearly shown that there is a risk of resistance development to all herbicides, and 2,4

- D and dicamba are no exception. In fact

, weeds have evolved resistance to nearly all forms of weed control including herbicides, tillage, mowing and hand weeding.

• The greatest risk for d eveloping herbicide resistance is actually occurring right now with the PPO herbicides and glufosinate. These products are being over

- used in certain cropping systems as farmers have no other effective herbicide options. The 2,4

- D and dicamba resistant cro ps could be used to delay resistance development to the PPO herbicides and glufosinate and, in turn, weed management systems could be developed using the PPO herbicides, glufosinate, 2,4

- D and dicamba, extending the life of each of these chemistries.

• Growe rs need multiple modes of action to help manage herbicide

- resistant weeds.

• Because of the resistance threat, growers are now more likely than ever to utilize multiple weed management strategies (tillage, row spacing, cover crops, residual herbicides, mecha nical cultivation, and hand

- weeding) in combination with herbicide

- resistant crops.

• APHIS provides no empirical assessment of farmer use of resistant weed mitigation measures at all, but rather flaccidly relies on Dow’s stewardship program, which is quite similar to Monsanto’s stewardship program for RR crops.

• APHIS fails to provide any critical assessment of Dow’s stewardship plan.

• Evaluate the potential for the increased use of 2,4

- D associated with the adoption of DAS corn and soybean events to exacerbat e the problems of herbicide

- resistant weeds by accelerating the evolution of 2,4

- D resistant weed populations.

• The Enlist TM technology will not be an exclusive answer to resistance development, but will be an extremely important tool in the development of c omprehensive, science

- based approaches to resistance management.

• APHIS fails to provide any assessment of the special proclivity of HR crop systems, or DAS

‐ 68416

‐ 4 soybean in particular, to trigger evolution of resistant weeds. The rapid emergence of GR w eeds in RR crop systems is evidence of the resistant weed

‐ promoting effect of HR crop systems in general and a proper analysis would have provided APHIS with important insights into the risks of resistant weed evolution in the context of the DAS

‐ 68416

‐ 4 so ybean system.

• Evaluate the potential for 2,4

- D

- resistant weeds in 2,4

- D resistant cropping systems. APHIS must take into account the reasonably foreseeable impact of future 2,4

- D resistant crop deregulations in analyzing the development of superweeds that are resistant to 2,4

- D and “fop” herbicides. Multiple resistance will develop in response to widespread use of 2,4

- D in corn and soon, if approved, in soybean and cotton.

• Without effective herbicide options for controlling resistant weeds, growers are le ft with no choice but to re

- introduce intensive tillage systems for weed management.

• Resistance to auxin herbicides has not been prevalent throughout the world (relative to other commonly used herbicides such as atrazine, imazethapyr, or glyphosate) due to at least three main reasons: (l) auxin herbicides have a complicated mode or action with multiple target sites (Kelley and Riechers, 2007), (2) weeds that evolve resistance to auxin herbicides have typically displayed a 'fitness cost', which means that th e plant is less physiologically fit or less competitive in the absence of the herbicide in relation to wildtype (i.e., sensitive to 2,4

- D) plants, and (3) auxin herbicides have rarely been used by themselves but are instead typically applied in tank mixtur es. Page 2

- 6• Resistance to 2,4

- D and dicamba represents no more a threat to agricultural production than resistance to other critical herbicides and the likelihood that it will be used in a manner consistent with best management practices is good.

• Stacking 2,4

- D an d dicamba tolerance with that of glyphosate, glufosinate, and other herbicide tolerant traits will further facilitate the use of these herbicides in a diversified program. Stacking herbicide traits does not in itself promote the evolution of resistance to more than one herbicide since, just as for individual herbicides, the evolution of resistance is a function of how the herbicides are used rather than a function of the selectivity of the crop to multiple herbicides.

5. Impacts Resulting from the Increase of Resistant Weeds

• Assess the reasonably foreseeable impact of increased tillage, soil erosion, and herbicide use to control weeds that become resistant to 2,4

‐ D, quizalofop

, and/or glyphosate.

• APHIS provides no meaningful assessment of the costs to farmers or U.S. agriculture from the reasonably foreseeable evolution of weeds resistant to 2,4

- D or glufosinate.

• Provide assessment of the impacts or costs to farmers of past herbicide resistance that has triggered pattern s of weed control, the use of her bicides, and the increased cost to farmers.

• Discuss the increasing costs and labor to combat resistant weeds that persist and spread in fields.

• Because the development of herbicide

- resistant weeds and volunteer corn are reasonably foreseeable impacts of 2,4

- D resistant corn cultivation, the analysis needs to consider the negative impacts on conservation tillage.

• Herbicide

‐ resistant weeds lead directly to adverse impacts on farmers, the environment and public health. Adverse impacts include the increased costs incurred by growers for additional herbicides to control them, greater farmer exposure to herbicides

, consumer exposure to herbicide residues in food and water, soil erosion

, greater fuel use and emissions from increased use of mechanical tillage to control resistant weeds, environmental impacts from herbicide runoff, and in some cases substantial labor costs for manual weed control. These are some of the costs of unsustainable weed control practices, the clearest manifestation of which is evolution o f herbicide

‐ resistant weeds.

• As the spread of glyphosate

- resistant weeds occurred, the adoption of tillage, including deep tillage with a moldboard plow has once again become more common. The return of conventional tillage has led to increased wind and wa ter erosion. Neither 2,4

- D nor dicamba technologies would eliminate tillage, but they would greatly reduce the need for deep tillage allowing many farmers to return to more reduced tillage production systems.

• APHIS must assess the potential for 2,4

- D crop systems to foster resistance, not only to 2,4

- D, but also to dicamba, and the impacts such cross

- resistant weeds (against a background of resistance to glyphosate, ALS inhibitors

, and/or other herbicides), would have on weed control in soybeans, corn

, and other crops. Known weed biotypes with resistance to either 2,4

- D or dicamba should be tested for tolerance to the other, to help establish the potential for such cross

- resistance.

• APHIS must assess the potential for 2,4

- D crop systems to further increase s oil erosion through increased use of tillage to control the 2,4

- D

- resistant weeds that will be generated by these crop systems.

Page 2

- 76. Weed Resistance Management

• Evaluate in detail the farmer use of resistant

- weed mitigation measures or effectiveness of the mit igation measures.

• Provide an assessment of weed resistance stewardship, including the flaws of past stewardship plans or how they might be improved.

• APHIS failed to consider that the value of crop rotation for suppressing weeds is undermined when rotated c rops are resistant to the same herbicides.

• New and expanded uses of existing herbicides are needed for integrated weed management programs in order to mitigate weed resistance and meet our current and future crop production needs.

7. Volunteer Corn/Soybean

• Estimate the cost to farmers for controlling volunteer DAS

‐ 40278

‐ 9 corn which will become a problematic “resistant weed” in its own right by virtue of its resistance to two to four herbicides.

• Assess the dispersal of herbicide resistance traits via pollen or seed dispersal or its implications for stewardship practices.

• Dow discusses the potential for DAS

- 68416

- 4 soybean to cross with soybeans possessing other herbicide resistance traits to produce soybean volunteers with resistance to additional herbicides . Indeed, three different GE soybean events with resistance to dicamba (Monsanto), the HPPD inhibitor isoxaflutole (BASF), and imidazolinone herbicides (Bayer) are presently pending deregulation decisions by USDA (APHIS Pending Dereg 2012) . Such crossing c ould result in volunteer soybeans resistant to four or more classes of herbicide.

• Soybean is primarily a self

- pollinating crop, but the potential for perhaps considerable

cross

- pollination is suggested by the frequency with which pollinators

– bees (honeyb ees and wild bees), wasps

, and flies

– visit soybean fields (Anonymous 2012, O’Neal & Gill 2012) . Insect pollinators are known to effect pollination at considerable distances from the source plants, including from primarily self

- pollinating crops (e.g. Pas quet et al. 2008).

• Even if soybean cross

- pollination is relatively uncommon, it could give rise to problematic volunteer HR soybean control problems where it does occur, with the adverse consequences noted above.

• APHIS should consider scenarios with volunteers that have stacked resistance. The assessment should include increased costs of control, increased use of herbicides, increased weed resistance risks from a narrowing of herbicidal control options

, and increased reliance on those (few) herbicides still effective.

• HR corn volunteers produce lower levels of Bt toxin and thereby promote Bt resistance in corn rootworm; the more HR traits in the corn volunteers, the less likely they will be managed adequately, and hence the more likely they will contri bute to Bt resistance.

8. Impacts on Organic and Non

- GE Crops

• Assess the socioeconomic impacts of transgenic contamination on the entire organic industry. Page 2

- 8• Complete a full analysis of the economic impacts due to GE contamination for organic and

non

- GE growers. GE crops can cross

- pollinate with non

- GE crops, contaminating conventional or organic crops. This contamination can result in a rejection of loads by t he Organic Trade Association, resulting in economic losses for farmers, previously estimated at 40 million dollars annually. APHIS needs to reevaluate the effect of DAS

- 40278

- 9 corn on organic corn, as cross

- pollination may pose a plant pest risk.

• Includ e an analysis of the cost of testing, tracing and separating DAS

- 40278

- 9 corn and DAS

- 68416

- 4 soybeans to avoid contamination of non

- GE crops and the subsequent impact on exports.

• Assess the potential impacts of deregulating 2,4

- D

- resistant corn on the su pply of organic corn feed.

• G enetic admixture is an environmental concern that can cause the alteration of a plant’s deoxyribonucleic acid (DNA) by transmitting a GE gene to a non

- GE plant, in turn, causing a loss of biodiversity that could result in the po tential elimination or reduction of conventional and organic corn varieties.

• Evaluate the impact of deregulating 2,4

- D resistant corn and the subsequent transgenic contamination on both the public’s and the grower’s ability to choose non

- GE corn; and consi der individual choice or the social or economic impact of eliminating that choice.

• Evaluate the impacts of GE admixture through feed and food products on animal and human food chains, and related human health impacts.

9. Cumulative Impacts

• Address the poten tial cumulative environmental impacts resulting from reasonably foreseeable future crops with “stacked” genetic traits.

• Consider the cumulatively significant impacts of all synthetic auxin herbicide

- tolerant crops.

• Impact analysis should consider drift not only from 2,4

- D resistant corn, but also the use of 2,4

- D in other reasonably foreseeable 2,4

- D

- resistant GE crop systems that are now pending before APHIS.

• Assessment of the resistant weed impact of DAS

- 68416

- 4 soybean grown in rotation with Enlist TM corn

.
• Dow plans to sell this GE 2

- 4,D soy “stacked” with resistance to glyphosate and glufosinate herbicides, yet neither Dow nor USDA has analyzed the potential synergistic or cumulative impacts that these planned combinations pose. Glufosinate has both repro ductive and neurological toxicity to mammals, and on this basis is slated to be banned in the EU by 2017.

• Assess the cumulative impacts of growing multiple HR crops, including changes in herbicide use patterns, weed resistance, human health effects, environmental effects from herbicide drift and runoff, and harm to wildlife, in particular threatened and endangered species and their critical habitats.

• APHIS must take into account any reasonably foreseeable impacts of conferring multiple herbicide

- resis tant traits via stacking of different resistance traits in the same crops, growing crops with different resistance traits in the vicinity of each other within a given year, and using the same resistance traits in rotation crops, for example.

Page 2

- 9The following issues related to herbicide use were identified from public comments. As noted, above, herbicide use is regulated by EPA. EPA is evaluating DAS' submission for their new 2,4

- D choline salt formulation and will be making those assessments available to pub lic. Therefore, these issues are listed here but for the most part are not being addressed in this EIS. When these issues are covered

, they are included in the Appendices.

Herbicide Use and Impacts from Herbicide Use

• Examine the potential for increased use of 2,4

- D, glyphosate, glufosinate, and quizalofop associated with deregulation of DAS

- 40278

- 9 corn, DAS

- 68416

- 4 soybean, and DAS

44406

- 6 soybean. Consider the rate applied per application, number of applications per season, and number of acres planted

.
• Project the shift in herbicide use patterns associated with DAS

- 40278

- 9 corn, DAS

- 68416

- 4 soybean, and DAS

- 44406

- 6 soybean.

• USDA has not thoroughly assessed the environmental risks associated with many of these transgenic crops. 2,4

- D is a volatile herbicide, which can easily drift onto nearby crops, vegetables and flowers. In fact, a comparative risk assessment found that 2,4

- D was 400 times more likely to cause non

- target plant injury than glyphosate.

• The transgene confers resistance to 2,4

- D, gluf osinate, and glyphosate, and in conjunction with the insertion site and genetic background of the host plant, determines how much 2,4

- D, glufosinate, and glyphosate can be applied and when during the growing season without injuring the crop. Thus the patte rn of tolerance to the herbicide(s) is event

- specific and should be described by the applicant in the Petition, and the implications rigorously explored by APHIS in a robust analysis pursuant to the National Environmental Policy Act (NEPA) and the Plant Pr otection Act.

• Compare increased herbicide use to conventional varieties.

• APHIS must disclose and analyze the impacts of herbicides used on a deregulating DAS

40278

- 9 corn on both organic and conventional non

- GE corn.

• Fully address impacts from the shift of use rates among different herbicides that may accompany deregulation of DAS

- 40278

- 9 corn, DAS

- 68416

- 4 soybean, and DAS

- 44406

- 6 soybean

.
• Provide a detailed examination of the cumulative effects of stacking 2,4

- D resistant corn with other herbicide toleranc es.

• Acreage likely to shift in herbicide use from glyphosate to synthetic auxin herbicides is not identified.

• If an engineered crop is immune to injury even at rates higher than allowed by label or at later times in development, experience has shown that growers will push or exceed the label limits in situations where there is weed pressure. APHIS needs to explore the implications of removing biological constraints to herbicide use in their assessments.

• USDA must consider the biological opinion of the Nat ional Marine Fishery Service regarding 2,4

- D registration.

• Benefits of 2,4

- D technology for the Georgia cotton grower would include: 1) Improved weed control; 2) Prevention of additional herbicide resistance development; 3) Reduction in herbicide use; and 4) Reduction in tillage, wind erosion, and soil erosion.

Page 2

- 10• An enormous amount of research by the registrants and other weed scientists around the world has been conducted to develop methods to minimize the potential for off

- target movement. These efforts in clude 1) improving herbicide formulations, thereby reducing volatility and/or drift, 2) improving application equipment techniques and application methods, thereby reducing drift, and 3) developing educational materials to assist growers in reducing off ta rget movement when making pesticide applications. There is no question these research efforts will greatly minimize off

- target movement of all pesticides, not just 2,4

- D and dicamba, and will greatly improve the ability of a grower to apply pesticides that stay in the targeted area.

• APHIS must project the impact of 2,4

- D

- resistant corn and soybean systems (with additional resistance to glyphosate and/or glufosinate) in further reducing populations of milkweed in agricultural fields and thus exacerbating the decline in Monarch populations.

• APHIS must assess the impacts of 2,4

- D

- resistant corn and soybean systems (with additional resistance to glyphosate and/or glufosinate) on amphibian populations.

Herbicide Use

- General

• Any questions or concerns about the use of 2,4

- D in a 2,4

- D

- tolerant soybean cropping system should continue to be addressed through the authority of the Environmental Protection Agency (EPA) to regulate the safe use of registered herbicides.

• Assess potential impacts to animals in fields of DAS

‐ 68416

‐ 4 soybean in light of the foreseeable increase in exposure to herbicides and their metabolites based on realistic use scenarios and a wide range of relevant independent scientific studies in order to compare alternatives.

• Assess the potential of the Enlist TM corn and soybean systems to increase drift

- related crop injury as well as potential mitigation measures.

• Assess the negative environmental impacts of pesticide drift associated with the prevalence of glyphosate

- resistant weeds.

• Assess cumul ative impact of a combination of herbicides on water resources, including the impacts to surface water from off

- site movement of herbicides.

• APHIS should consider late, off

- label treatment of crops, and include protection of insects, birds, reptiles, amphi bians or other animals.

• Examine impacts that increased herbicide use in DAS

‐ 68416

‐ 4 soybean would have on those nearby habitats.

• The potential impact on the plant population diversity within treated fields of DAS

- 40278

- 9 corn and the resulting impacts to a nimals from those changes should be evaluated.

• Concerns about the impacts to plant and animal biodiversity in and around cornfields from increased pesticide use due to implementation of DAS

- 40278

- 9 crop systems.

• The estimated increase in herbicide use would likely jeopardize species and critical habitats protected under the Endangered Species Act (ESA). A “failure by USDA to recognize the risks of jeopardizing endangered species and adversely modifying their critical habitats would not be in compliance with the statutory requirements of the National Environmental Policy Act (NEPA).”

• Dow plans to sell this GE 2

- 4,D soy “stacked” with resistance to glyphosate

— the active ingredient in Roundup

— and glufosinate herbicides, yet neither Dow nor USDA has

Page 2

- 11analyze d the potential synergistic or cumulative impacts that these planned combinations
pose.

• The ability to effectively control weeds is one of the most important factors in profitable crop production. The use of glyphosate in Roundup Ready crops was a highly cost

effective approach to weed control for many years, but heavy reliance on glyphosate

- only weed control programs eventually led to the development of glyphosate resistant weeds, including marestail, waterhemp, Palmer amaranth, kochia and giant ragweed, that are difficult to control with current technologies.

• Weed management will be much more successful if post

- emergence 2,4

- D treatments are used in conjunction with pre

- emergence residual herbicides that can provide extended control. The use of pre

- emer gence herbicides as part of an integrated approach has increased in recent years due to the difficulties of controlling glyphosate resistant weeds and because of the improved commodity prices. This approach helps minimize potential for early season weed co mpetition and provides more flexibility and better efficacy with the post

- emergence treatment. The other huge benefit is that by utilizing more herbicide modes of action, the risk of developing herbicide resistant weeds is greatly diminished.

Herbicide Us e - 2,4

- D

• Assess impacts associated with the potential increases in use of 2,4

- D, quizalofop, and their metabolites on non

- target animal communities, particularly on the honeybee population.

• Thoroughly evaluate the likely increase in 2,4

- D application, al ong with the associated environmental and public health impacts.

• Adequately account for the unique risks associated with 2,4

- dichlorophenoxyacetic acid (2,4

- D) herbicides.

• Evaluate health risks posed by drift of 2,4

- D onto unsuspecting victims. There is no worse herbicide for drifting long distances and damaging fruit and vegetable plants than 2,4

- D, and the introduction of these resistant varieties will make it far more likely that such drift will be occurring with increasing frequency in the f uture. For some growers, it will make their livelihoods untenable and for homeowners in the country, they will see increasing damage of their gardens and trees of 2,4

- D drift.

• APHIS and EPA must assess the increased incidence of disease to be expected with the substantial increase in 2,4

- D use accompanying introduction of these crop systems.

• Farmers have a long history of successfully using proper equipment and application procedures to avoid and minimize off

- target movement of herbicides. Similarly to othe r herbicide products, off

- site movement of 2,4

- D can be prevented through proper stewardship, application techniques, equipment settings and consideration of environmental conditions during application, such as wind speed..... newer 2,4

- D formulations have b een developed to substantially reduce volatility compared to first

- generation products. We are also pleased that the petitioner has addressed the potential for off

- site movement by prohibiting aerial applications and implementing specific environmental and equipment application requirements on the 2,4

- D label, including a wind

- directional buffer when sensitive areas are present, and the use of low volatility 2,4

- D formulations.

• Adequately assess the potential for an increased health risk to farmers and farm workers using 2,4

- D.

Page 2

- 12• APHIS needs to reconsider potential risks to animal communities from eating DAS

- 68416

‐ 4 soybean tissues or drinking runoff containing residues of 2,4

- D and the unique metabolites.

• The developer in the future may petition the EPA for an increased tolerance for 2,4

- D simply because residues increase with increased 2,4

- D use, and that APHIS should consider the health implications of such higher levels of 2,4

- D likely to be found in food. USDA must consider the effects that higher 2,4

- D re sidues in food would have on human health.

• Account for the risks associated with 2,4

- D and their severity relative to the potential harm associated with other herbicides.

• Increase in 2,4

- D use would increase the amount of herbicide in surface waters, adve rsely impacting drinking wa ter quality. This will have implications for fragile wetland areas, especially those under conservation.

• Impacts need to be assessed not only for the direct toxicity of the herbicides (2,4

- D and quizalofop) and their metabolites on animal communities, but also for animals that may be indirectly exposed by over

- spraying, brushing up against newly sprayed foliage, or feeding on corn leaves that may receive a higher dose of herbicide, as well as drinking surface water potentially im pacted from surface runoff containing the herbicides.

• APHIS must comprehensively assess the increased drift damage that would occur with various 2,4

- D

- resistant corn and soybean adoption scenarios, both in terms of lost yield and income, broken down by major crop (e.g. soybeans, cotton) or crop category (e.g. vegetables). APHIS should further assess the extent to which 2,4

- D

- resistant crop adoption would reduce plantings of susceptible crops (e.g. vegetables, grapes) and/or shift acreage to 2,4

- D

- to lerant crops that could withstand drift level doses (e.g. corn).

• APHIS must account for the inevitable use of more drift

- prone 2,4

- D formulations (e.g.

, because likely to be cheaper than the choline salt), and not presume an ideal world scenario where only potentially less drift

- prone formulations are used.

Herbicide Use

– Glufosinate

• Analyze the health impacts stemming from the expected increase in use of glufosinate.

• Glufosinate poses significant ecological risks to non

- target plants and animals and the implications from increased use as a result of the determination of nonregulated status of DAS

- 68416

- 4 Soybean should be included in the EA.

• Analyze t he potential impact from the metabolite of glufosinate, methylphosphinicopropionic acid (MPPA), which could also pose human health risks, especially to pregnant women and their fetuses. Research should be completed on this metabolite to ensure that it wil l not be detrimental to wildlife, especially those plants and animals protected by the Endangered Species Act.

Herbicide Use

– Quizalofop

• Need complete information on the environmental impacts of 2,4

- D and quizalofop.

• Perform human health assessment of the occupational exposure to quizalofop

• Assess impacts associated with the potential increases in use of 2,4

- D, quizalofop, and their metabolites on non

- target animal communities, particularly on the honeybee population.
Page 2

- 13• Impacts need to be assessed not only for the direct toxicity of the herbicides (2,4

- D and quizalofop) and their metabolites on animal communities, but also for animals that may be indirectly exposed by over

- spraying, brushing up against newly sprayed folia ge, or feeding on corn leaves that may receive a higher dose of herbicide, as well as drinking surface water potentially impacted from surface runoff containing the herbicides.

• Synergistic effects of the combined use of 2,4

- D and quizalopfop have not been considered for the increased ecological risks.

Herbicide Use

- Dioxin Impurities in 2,4

- D

• USDA and EPA should conduct an assessment of the greatly increased exposure to dioxins that would be triggered by Enlist TM soybeans and corn in light of EPA’s ongoin g review of dioxin toxicity, both cancer and non

- cancer risks.

• Include analysis for the health impacts from dioxin contamination in 2,4

- D. Impacts to human reproduction and to workers from exposure to dioxin (especially 2,3,7,8

- TCDD) have not fully been c onsidered and analyzed and request that these impacts be analyzed.

• Assess potential short

- and long

- term impacts on animals from the dioxin impurities, as well as 2,4

- D.

• Evaluate potential effects of the dioxin impurities on treated pollen from DAS

- 40278

- 9 corn on honeybees and other animal populations that are in contact with/collect pollen.

• Need cumulative effects on human health and environment from dioxin and potential effects on surface water quality and non

- target plants and animals (including endange red species).

• Assess the increased dioxin emissions and exposure associated with incineration of unrinsed 2,4

- D containers that would result from the vastly increased use of 2,4

- D with Enlist TM soybeans and corn.

• USDA should conduct or commission independen t dioxin testing of 2,4

- D formulations.

Herbicide Use

- 2,4

- D Metabolites

• APHIS failed to fully consider the impacts of increased 2,4

- D use, related DCP

- conjugates, and increased glyphosate.

• APHIS needs to consider the impacts to human health of exposure to DCP and DCP conjugates that are a result of the activity of the engineered AAD

- 12 enzyme in DAS

68416

- 4 soybean.

• The types and levels of DCP and DCP conjugates in DAS

‐ 68416

‐ 4 soybean forage and hay after 2,4

‐ D applications need to be compared with inde pendent research on 2,4

‐ D and DCP metabolism in conventional soybeans (Pascal

‐ Lorber et al. 2003), with any differences explained.

• DCP conjugates were not included in the evaluation of whether DAS

- 40278

- 9 corn will meet tolerance requirements in forage and fodder, and suggested that, if DCP conjugates had been included, with the assumption of similar toxicity to free DCP, tolerance levels would be exceeded

• APHIS should consider levels of all expected toxic residues and metabolites; and assess impacts to non
‐ target organisms of the novel, potentially toxic constituents expected to
Page 2

- 14result when 2,4

‐ D with DAS

‐ 68416

‐ 4 soybeans under a variety of anticipated application scenarios.

• Evaluate potential impacts of pollen containing residues and metabolites not fou nd in conventional pollen that might make it toxic to organisms that come in contact with it.

• APHIS did not take into account independent research and Dow studies showing that potentially toxic metabolites do occur as a result of the engineered trait. USDA should carefully consider the impacts of the accumulation of novel molecules with similarity to known toxins in DAS

- 68416

- 4 soybean. APHIS needs to know if the AAD

- 12 enzyme alters metabolism in DAS

- 68 416

- 4 soybean such that the plants have a new composition after 2,4

- D is used, and thus have the potential to harm non

- target species. APHIS must consider whether DCP and its conjugates are present in soluble fractions of DAS

- 68416

- 4 soybeans after AAD

- 12 enzyme acts upon 2,4

‐ D in order to fully assess the impacts to non

target organisms and on human health.

• APHIS should consider whether DCP and it s conjugates are present in soluble fractions of DAS

- 40278

‐ 9 corn after the AAD

‐ 1 enzyme acts upon 2,4

- D in order to fully assess the “plant pest risks” to non

- target organisms

• Consider the possible toxicity of the metabolites that are present in DAS

- 40278

- 9 corn exposed to herbicide substrates of the ADD

- 1 protein, and the impact of this toxicity to listed species requiring formal USFWS consultation.

• Information on the herbicide residues and metabolites in plant tissues from the time of application throug h post

- harvest should be available for review by APHIS and the public

Page 2

- 15Table 2

- 1 . EIS Public Scoping Comments Submitted Online Comment # Comment ID Commenter Comment Excerpt Topic Area 1 APHIS

- 2013

- 0042

- 0002 Jean Public The American Public wants this permit denied. Monsanto and Dow are releasing harmful items to the American Public with these unregulated soybean and corns. N/A

2 APHIS

- 2013

- 0042

- 0003

Carl Bausch Undertaking the National Environmental Policy Act process for the identified petitions is both wasteful and superfluous. N/A

Granting (with or without conditions) or denying a petition does not constitute “alternatives” to be considered in the NEPA process; rather, they are decision options for the agency. Alternatives that must be considered under NEPA relate directly to the p urpose and need for a proposed action, the statement of which, again, is missing from the notice. 3 APHIS

- 2013

- 0042

- 0004 Illinois Farm Bureau (IFB)

– Philip Nelson These traits have already gone through USDA's rigorous regulatory review protocol and th ere have been no scientific, findings to warrant additional EIS. On behalf of nearly 83,000 Illinois farmers, I write today to request

- that, APHIS move expeditiously when completing this seemingly superfluous regulatory review. Biotechnology has produced vast improvements in farm production practices, permitting farmers to do more with less. Herbicide

tolerant seeds are simply another tool for our producers to utilize towards helping feed the world's ever increasing population. These technologies will have a positive impact on farming and the food that we produce. 4 APHIS

- 2013

- 0042

- 0006 U.S. Department of Interior, National

Park Service

– Roxanne Runkel The National Park Service supports the objective identified or development of science that addresses the Environmental Issues for Consideration identified o pages 28799 [of the Federal Register notice]. The NPS is concerned about the indirect effects on the soil and water quality in NPS areas as a result of increased herbicide use. We believe the indirect effects on soil and water quality as a result of increased herbicide use of the products proposed to be de

regulated, be evaluated. Herbicide use

- effects on soil and
water

5 APHIS

- 2013

- Louis Metzman I implore you to not a pprove release of 2,4

- D resistant plants. I have Herbicide drift
Page 2

- 16Comment # Comment ID Commenter Comment Excerpt Topic Area 0042

- 0007 (grower) had collateral damage from 2,4

- D drift to my fruit orchard and my 5 acre tree planting and to landscape plants at my house 6 times over the past 14 years

- this is a very dangerous herbicide that tends to

va porize and cause damage to neighboring plants. This damage is all too common with this particular herbicide.

Forester Mike Warner, with Mike Warner ARBORTERRA Consulting, tells me he has been asked to check on 15 claims of what he feels are 2,4

- D damage so far this year. I can only imagine the damage we will see with more widespread use of this very dangerous chemical. It causes damage very far away to plants

- how will we know who did the damage, and how will we hold them responsible? And, with no accoun tability, they can spray with impunity. Also, perhaps in future years we will find out it was also harmful to the people who are also exposed to it.

6 APHIS

- 2013

- 0042

- 0009 David Ortman • The EIS should include an alternative prohibiting field testing of herbicide resistant corn and soybeans.

• The EIS should provide an estimate and analysis of the quantities of 2,4

- D and glyphosate that would enter watercourses and waterbodies, including within our nation’s coastal zone, under alternatives that would ban herbicide resistant corn and soybeans; that would continue herbicide resistant corn and soybeans as regulated articles; and under Dow AgroSciences LLC’s request for nonregulated status.

• The EIS should set out a testing protocol for determini ng the level of Glyphosate and 2,4

- D in water bodies in order to establish a baseline for future evaluations of Glyphosate and 2,4

- D use due to “herbicide resistant” corn and soybeans.

• The EIS should set out a testing protocol for determining the level of Glyphosate residues in shellfish and fish to assure that residue tolerances are not exceeded and to ensure that
Page 2

- 17Comment # Comment ID Commenter Comment Excerpt Topic Area 2,4

- D residues are not present. 7 APHIS

- 2013

- 0042

- 0011 Carl Bausch • Where specifically in chapter 104 of title 7 of the United States Code is APHIS authorized to regulate the introduction (importation, interstate movement, or release into the environment) of genetically engineered organisms and products?

• Why does APHIS feel it is necessary to undertake a costly (to industry and taxpayers), unnec essary environmental impact statement process when a conventional risk assessment establishes that the organism is not a plant pest and that APHIS therefore lacks jurisdiction (see my earlier comment for explanation)?

• The statement of purpose and need is m issing from the notices. To what need and for what purposes are petitioners responding in developing and commercializing their products? The answer to this question largely determines the range of reasonable alternatives the agency must consider in the N EPA process.

• Granting (with or without conditions) or denying petitions does not constitute “alternatives” to be considered in NEPA’s environmental impact statement process; rather, they are decision options for the agency (see my earlier comment for expla nation). Alternatives that must be considered under NEPA relate directly to the purposes of and need for proposed actions.

• APHIS NEPA documents are not written in plain language, as required by the NEPA implementing procedures (40 C.F.R. § 1502.8).

• Moni toring, which is an essential component of the NEPA process (40 C.F.R. § 1505.3), should be employed in biotechnology permitting to confirm assumptions made in NEPA documents and respond to many unanswered, but oft

Page 2

- 18Comment # Comment ID Commenter Comment Excerpt Topic Area repeated questions.

• APHIS has often claim ed that, although individual farmers may be affected by releasing genetically engineered organisms in the area, when examined in total, none of the potential business losses is expected to be so severe as to amount to a significant impact. This determinat ion fails to recognize that environmental “significance” exists at all levels―“society as a whole (human, national), the affected region, the affected interests, and the locality.” 40 C.F.R. § 1508.27(a).

• APHIS tends to rely on the United States Environme ntal Protection Agency’s (EPA) consideration of environmental effects in the context of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) registration process, as well as FDA’s determinations under its enabling legislation. The regulatory and review processes of EPA and FDA cannot be relied upon to relieve APHIS from considering in the context of the National Environmental Policy Act (NEPA) process any and all effects associated with release into the environmental of petitioners’ products.

• I n the past, APHIS appears to have placed a great deal of reliance on petitioners in complying with NEPA. Agencies have a responsibility under NEPA to independently investigate and assess the environmental impacts of proposals under consideration (40 C.F.R . § 1506.5(a) and (b)).

• There is considerable uncertainty regarding potential environmental effects of releasing genetically engineered organisms. Although an agency is not precluded from approving a particular proposal involving substantial uncertainty, it must disclose all areas of uncertainty. Save Our Ecosystems v. Clark , 747 F.2d 1240, 1246 (9th Cir.
Page 2

- 19Comment # Comment ID Commenter Comment Excerpt Topic Area 1984).

• The taxpayer and the agricultural biotechnology industry would be better served if APHIS announced it would no longer “regulate” agricultural bi otechnology because there has not been a proven plant

- pest risk associated with the technology in decades, perhaps ever. APHIS

- 2013

- 0042

- 0010 Carl Bausch Duplicate of comment APHIS

- 2013

- 0042

- 0003 N/A

8 APHIS

- 2013

- 0042

- 0012 Tess Cramer Once GMO's are introduced into the environment, there is no way to recall them OR their genetic pollution to organic crops. N/A

9 APHIS

- 2013

- 0042

- 0013 Arthur Tesla These plants will turn up as volunteer weeds in other farmers fields Plant Communities 10 APHIS

- 2013

- 0042

- 0014 MS Lower glyphosate and Round Up now. Do not do what you're planning on doing, EPA and raise the limits. It's already at very toxic levels and raising the limits of poison is not only going to be doing the exact opposite of what you're supposed to be in your job but the very exact opposite. Do not allow your ethics and conscience from deep within to be override by greed and money. Do what's right for the environment and protect it. Herbicide use

– glyphosate limit

11 APHIS

- 2013

- 0042

- 0015 Renae Hockaday • Why is nonregulation even being considered?

• There's too much impact on people's health and neighboring (organic and non) producers.

• To put GMO into foods without being listed as GMO in the ingredients is blatant dishone sty. At the very least products from GMO must be listed in the ingredients label. FDA

- labeling

12 APHIS

- 2013

- 0042

- 0016 Jordan Scheibel (grower) • There is no worse herbicide for drifting long distances and damaging fruit and vegetable plants than 2,4

- D, and the introduction of these resistant varieties will make it far more likely that such drift will be occurring with increasing frequency in the future. For some growers, it will make their livelihoods untenable and for homeowners in the country, they Herbicide use

- drift

Page 2

- 20Comment # Comment ID Commenter Comment Excerpt Topic Area will see increasing damage of their gardens and trees of 2,4

- D drift.

• The introduction of these varieties is an implicit admission that glyphosate resistant varieties are failing, weeds are becoming resistant, and stronger herbicides are needed. I shudder to think what herbicides will be necessary in 5 or 10 years as herbicide resistance continues to grow and the regulatory bodies that are supposed to be considering the long term implications of introducing these herbicide resistant varieties continue to

r ubber stamp them. 13 APHIS

- 2013

- 0042

- 0017 Martin Johnstone As there is no actual requirement for GM food, what makes you think you have the right to impose it upon the people without asking them if they want it? Is this the case: As k the people if they want GM products. You will never ask, because you know the answer will be no. Therefore you continue without asking, forcing people to 'accept' your products? You don't have the right to do that. N/A

14 APHIS

- 2013

- 0042

- 0018 Arthur Te sla History has shown these crops will appear as volunteer weeds in farmers fields and be difficult to control because they are herbicide resistant/ They are plant pests! They are also plant pests to consumers who don't want to eat these Dangerous genetically engineered foods. Plant communities

- volunteers

15 APHIS

- 2013

- 0042

- 0019 Anonymous Against Crop

Oppression America does not want to purchase biotechnology as a food source or fuel source. Europe does not want to purchase biotechnology as a foo d source or fuel source. The rest of the world does not want to have biotechnology as a food or fuel source imposed on them. There is no market for genetically modified, genetically engineered, genetically enhanced or altered food crops used for food or fu el. N/A

16 APHIS

- 2013

- 0042

- 0020 Klaas Raater Please consider the environmental impact of every country in the world hating America for its corporate fascism. I am already boycotting every American product. The same goes for my family and my friends. You h ave alienated yourself from the rest of the world. Way to go America! N/A

Page 2

- 21Comment # Comment ID Commenter Comment Excerpt Topic Area And i will not even spend a single holiday at your country anymore for the rest of my life. You want war with the rest of the world? No problem, you got it! I'd rather die than eat your Frankenfoods! 17 APHIS

- 2013

- 0042

- 0021 Doris Headley For some time now, knowing that what I purchase was produced in North America or the UK was my only safety net. If you take that away, I shudder to think what I could be consuming. N/A

18 APHIS

- 2013

- 0042

- 0022 Marina Vrouvlianis Stop poisoning the world N/A

19 APHIS

- 2013

- 0042

- 0023 Tanya Molyneux Weeds are becoming resistant to the chemicals we treat them with and the answer to just apply more herbicide is poisoning our ground and drinking water, the food that we feed to our animals and the food we are eating. Stop the insanity before its too late for the human race. N/A

20 APHIS

- 2013

- 0042

- 0024 JS Deran I am against any increase in herbicide resistant corn and soybeans. I don't think these crops should be allowed at all. I have seen the non

biased reports from France and read of problems on farms and ranches in many countries that used GE crops. I think that all the herbicide resistant corn and soybeans should be banned from use. There is so much evidence that shows these crops to be detrimental to people AND animals that to allow further use shoul d be criminal. N/A

21 APHIS

- 2013

- 0042

- 0025 Donna Deran Weeds treated with Glyphosate have become stronger from exposure so now they want to treat the SUPER weeds with more Glyphosate and then what will we have? Toxic wastelands with FRANKENWEEDS that noth ing can kill!!! When will this madness stop? Our land and food are already contaminated with this chemical and now they want to make it worse by increasing allowable toxic exposure!!! JUST SAY NO !!! The EPA's first job is supposed to be protecting people from harmful toxins, not selling us out for the BIG BUCKS, from BIG CHEMICAL companies. N/A

22 APHIS

- 2013

- 0042

- 0026 Dale Moore

- American Farm Bureau Federation (Farm Bureau) Farm Bureau respectfully asks APHIS to abide by the Ninth Circuit’s interpretat ion of its legal obligations under the PPA and NEPA and reconsider its decision to prepare EISs for the herbicide tolerant crops identified in the Notices. Farm Bureau asks APHIS to Oppose preparation of EIS

Page 2

- 22Comment # Comment ID Commenter Comment Excerpt Topic Area act expeditiously to finalize the deregulation process for these crops in keeping with the Ninth Circuit’s recent RRA decision and the APHIS regulations governing deregulation petitions. 23 APHIS

- 2013

- 0042

- 0027 Drew Kershen (The University of Oklahoma, College of Law) • If these seeds and plants are not plant pests, USDA

- APHIS should deregulate without further study.

• In the Notices for both docket items, USDA

- APHIS indicates that concerns about weed resistance related to herbicide usage is the driver behind the Notice to complete EISs. Yet, under
statutor y authority, EPA, through FIFRA, has the authority to regulate herbicides, including taking into account the environmental impact of weed resistance issues. EPA has exercised its authority under FIFRA and has authorized dicamba and 2,4

- D has herbicides. Wh en EPA exercises its authority under FIFRA, the EPA has performed an environmental analysis that is “functionally equivalent” to an EIS under NEPA. Oppose preparation of EIS

24 APHIS

- 2013

- 0042

- 0028 A. Stanley Culpepper

- University of Georgia, Weed

Scien tist, and grower Cotton weed management programs in Georgia have undergone, and are continuing to undergo, significant changes. Currently recommended programs are complex, costly, and challenging to implement in a timely fashion. Growers are desperately in need of new technologies to improve control of Palmer amaranth, reduce the potential for further herbicide resistance development to currently used tools, and to reduce the economic burden that Palmer amaranth is placing on the agricultural industry.

We admire and respect the desire of USDA and EPA to be certain that no agriculture technology will negatively impact the consumer, the user, or the environment in which we and our children live. Our request is simple, if deemed safe please assist in the move ment of all new technologies to our growers as rapidly as feasible. APHIS

- 2013

- 0042

- 0028 A. Stanley Culpepper

- • Herbicide

- resistance has significantly changed agriculture forever in the Southeast; especially for cotton growers. To
Page 2

- 23Comment # Comment ID Commenter Comment Excerpt Topic Area University of Georgia, Weed

Scientist, and grower combat this pest, growers have relied heavily on herbicides, tillage, and hand weeding. Herbicide use in cotton has increased sharply wit h 2.5

- times more herbicide active ingredient applied to cotton following the confirmation of glyphosate resistance in Palmer amaranth as compared to before documented resistance. Although grower herbicide input costs have more than doubled following the ev olution and spread of glyphosate resistance, Palmer amaranth control is still not adequate. Thus, 92% of Georgia cotton growers hand

- weed 52% of the crop with an average cost of $23 per hand

- weeded acre, which is an increase of at least 475% as compared to hand weeding costs prior to resistance. In addition to increased herbicide use and hand weeding, growers in Georgia have indicated that they are using mechanical, in

- crop cultivation (44% of acres), tillage for the incorporation of preplant herbicides (20 % of the acres), and deep turning (19% of the acres every three years) to aid in Palmer amaranth control. Current weed management systems are extremely diverse, complex, less environmentally friendly, and costly when compared to those systems employed only a decade ago. Growers are in desperate need of new technologies that will aid in the management of glyphosate

- resistant Palmer amaranth, and other problematic weeds, for long term sustainability. APHIS

- 2013

- 0042

- 0028 A. Stanley Culpepper

- University of Georgia, Weed

Scientist, and grower Benefits of 2,4

- D or Dicamba Technologies For the Georgia Cotton Grower: 1. Improved Weed Control: Neither dicamba nor 2,4

- D are consistently effective in controlling Palmer amaranth larger than 4 inches when applied alone (Culpepper et al. 2010; Culpepper et al. 2011; Merchant et al. 2011); however, weed management systems including these herbicides are more consistently eff ective than current standards (Braxton et al.

Page 2

- 24Comment # Comment ID Commenter Comment Excerpt Topic Area 2010; Beckie 2011; Merchant et al. 2013; Richburg et al. 2012; Shaw and Arnold 2012) . Weed management programs including 2,4

- D or dicamba would improve a grower’s ability to manage this problematic weed in the following ways: 1) improved consistency in weed control especially on dryland production acres where residual herbicides often are not activated with rainfall at planting time, 2) more flexibility with herbicide application timings because glufosinate plus dicamba or 2,4

- D will consistently control Palmer amaranth up to 6 inches in height (at least 2 inches larger than todays standards), 3) less herbicide carryover to subsequent crops because growers would be less dependent on long lasting residual herbicid es, and 4) less yield loss from Palmer amaranth crop competition for light, nutrients, and water (Coetzer et al. 2002; Culpepper et al. 2010; Merchant et. al 2013; MacRae et al. 2013). 2. Prevention of Additional Herbicide Resistance Development: USDA has vo iced concerns that growers may adopt 2,4

- D or dicamba technologies and rely too heavily on these herbicides thereby developing an even greater weed resistance scenario. Science has clearly shown that there is risk of resistance development to all herbicide s; dicamba and 2,4

- D are no exception. In fact, weeds have developed resistance to nearly all forms of weed management including herbicides, tillage, mowing and even hand weeding. Our data and surveys contrast the assumption that rapid development of resis tance to 2,4

- D or dicamba would occur in Georgia cotton. First, our data notes that since these auxin herbicides control only very small Palmer amaranth then they must be applied in tank mixtures with other herbicides such as glufosinate. Second, even mixt ures of glufosinate plus 2,4

- D or dicamba will only control Palmer amaranth less than six inches in height and since Palmer

Page 2

- 25Comment # Comment ID Commenter Comment Excerpt Topic Area amaranth can grow as much as two inches per day selective residual herbicides must be used throughout the season. Simply put, data t hroughout the belt supports the fact that over

- use and/or over

- dependence of 2,4

- D or dicamba in cotton would equal poor weed control and eventual crop failure which is a practice no grower would follow. Dicamba and 2,4

- D would be an additional tool to inc lude in the weed management program. The greatest risk for developing herbicide resistance is actually occurring at this moment with the PPO herbicides and glufosinate. These products are being over used as growers have no other effective herbicidal option s. New technologies such as dicamba or 2,4

- D could be used to delay resistance development to the PPO herbicides and glufosinate and, in turn, systems could be developed using the PPO herbicides, glufosinate, 2,4

- D, and dicamba extending the life of each o f these chemistries. It is also critical to stress that, at least in Georgia, no weed management program relies exclusively on herbicides. The University of Georgia Weed Science Extension Team stresses to growers at more than 50 meetings each year that he rbicides are only one part of the weed management program. Sustainability is only possible with the adoption and implementation of diverse management programs and Georgia growers have accepted this message as fact (Sosnoskie and Culpepper 2013). Growers ar e using programs that are complex and diverse integrating herbicides, hand weeding, and tillage or cover crops. Neither dicamba nor 2,4

- D would change this approach but would simply be an additional tool to add into these management systems. 3. Reduction i n Herbicide Use: Glyphosate

- resistant Palmer amaranth has increased herbicide pounds of active ingredient applied in Georgia cotton by a factor of 2.5 when compared to

Page 2

- 26Comment # Comment ID Commenter Comment Excerpt Topic Area herbicide use prior to resistance (Sonoskie and Culpepper 2013). Programs developed by t he University of Georgia for 2,4

- D or dicamba technologies suggest the pounds of herbicide active ingredient may be able to be reduced by at least 30% while actually providing better weed control; similar results are also noted in other areas across the co tton belt (Edwards et al. 2013; Merchant et al. 2013; Smith and Hagood 2013; Steckel et al. 2013). 4. Reduction in Tillage, Wind Erosion, and Soil Erosion: As the spread of glyphosate

- resistant Palmer amaranth occurred, the adoption of tillage including d eep turning of the land with moldboard plows has become common (Sosnoskie and Culpepper 2013). The return of conventional tillage has led to increased wind and water erosion. Neither 2,4

- D nor dicamba technologies would eliminate tillage, but they would gr eatly reduce the need for deep tillage allowing many growers to return to more reduced tillage production systems. This opportunity to return to reduced tillage systems would be in response to a more consistently effective management program. APHIS

- 2013

- 0042

- 0028 A. Stanley Culpepper

- University of Georgia, Weed

Scientist, and grower Concerns With 2,4

- D

- or Dicamba

- Resistant Technologies:

1. Off

- Target Movement: Off target movement of 2,4

- D and dicamba pose the greatest limitation to the ad option of either auxin technology. Although it is currently unknown what restrictions will be in place to minimize off

- target movement by herbicide labels, an enormous amount of research by the registrants and other scientists across the world is being con ducted to develop methods to minimize the potential for off

- target movement. These efforts include 1) improving herbicide formulations, thereby reducing volatility and/or drift, 2) improving application equipment techniques and application methods, thereby reducing drift, and 3) developing educational materials to assist growers in reducing off target movement when

Page 2

- 27Comment # Comment ID Commenter Comment Excerpt Topic Area making pesticide applications (Bagley 2013, Huff et al. 2013; Kendig et al. 2013; Magidow et al. 2013; Newsom et al. 2013; Reynolds et al. 2013, Sandbrink et al. 2013). Benefits from these efforts will be monumental in minimizing off

- target movement of ALL pesticides, not just 2,4

- D and dicamba, and will greatly improve the ability of a grower to apply pesticides that stay in the targeted area. In Georgia, the University of Georgia and the Georgia Department of Agriculture are currently developing additional methods to further minimize off

- target movement of auxin herbicides and other pesticides. Also, a cooperative effort between The University of Georgia, Georgia Department of Ag, Agronomic Industry leaders, and Horticultural Industry leaders is underway to further define methods to minimize off

- target movement. 25 APHIS

- 2013

- 0042

- 0029 Andrew LaVigne

- American Seed Trade Association The Notices of Intent published on May 16 identify two issues that led APHIS to conclude that EISs were required by NEPA

– the development of herbicide

- resistant weeds (i.e., weed resistance) and increased herbicide use. Both of these issues relate solely to the herb icides, such as 2,4

- D and Dicamba, that would be available for use in conjunction with the crops modified to tolerate their application. As such, these issues are subject to the exclusive jurisdiction of the U.S. Environmental Protection Agency (“EPA”) und er the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”) and are decidedly not subject to APHIS’s jurisdiction under the Plant Protection Act (“PPA”).

ASTA and its members support a science

- based, federal environmental review process for new b iotechnology seed products. That process must recognize the distinct products, federal actions, and statutory mandates of the regulatory agencies involved. We are concerned, however, that by basing its decision to prepare EISs on the potential environmenta l effects of the herbicides rather than the associated herbicide tolerant crops, APHIS has failed to recognize those Oppose preparation of EIS

Page 2

- 28Comment # Comment ID Commenter Comment Excerpt Topic Area distinctions. Moreover, the EIS preparation process will unnecessarily delay issuance of determinations of nonregulated status for these cr ops with no additional benefit to the environment. 26 APHIS

- 2013

- 0042

- 0030 Danny Murphy

- American Soybean Association Soybean farmers need new technologies such as 2,4

- D

- tolerant soybeans to increase yields, manage weed resistance and maintain profitability. In light of the recent ruling by the Ninth Circuit Court of Appeals on the Roundup Ready alfalfa case

-- which confirmed that issues relating to the use of herbicides are the responsibility of the Environmental Protec tion Agency (EPA), not USDA

– ASA strongly urges USDA to reconsider its decision to require an EIS. According to the Notice of Intent, USDA’s basis for conducting the EIS all relate to herbicide uses, and the recent Ninth Circuit decision made clear the Fr amework 1 under which regulatory authority is allocated among USDA, Food and Drug Administration (FDA) and EPA, and where USDA has no jurisdiction over herbicides nor for consideration of herbicide impacts related to its obligations under the Plant Protecti on Act. Conducting a time

- consuming analysis already within the responsibilities of other federal agencies will cause a significant delay in bringing needed technologies to growers and is not consistent with the Plant Protection Act and the Administrative Procedure Act. The Ninth Circuit decision leaves no doubt that USDA does not need to analyze herbicide resistance or other impacts related to herbicide use in connection with petitions to deregulate herbicide

- tolerant crops. It remains EPA’s responsibility to prescribe the conditions in which it may be used.

Further, the Ninth Circuit made clear that APHIS’ regulatory jurisdiction ceases once APHIS determines that a crop is unlikely to Oppose preparation of EIS

1 Congress allocated regulatory authority of biotechnology derived crops under the Coordinated Framework. 51 Federal Register 23302

- 09. June 26, 1986.

Page 2

- 29Comment # Comment ID Commenter Comment Excerpt Topic Area pose a plant pest risk. The Court ruled, “If APHIS concludes that the presumptive plant pest does not exhibit any risk of plant pest harm, APHIS must deregulate it since the agency does not have the jurisdiction to regulate organisms that are not plant pests.” APHIS already has determined that Enlist TM soybeans are unlikely to pose a plant pest risk. Thus, proceeding with an EIS would be contrary to the decision of the Ninth Circuit. APHIS

- 2013

- 0042

- 0030 Danny Murphy

- American Soybean Association With mounting pressure to manage resistant weeds, soybean growers need new multiple

- mode

- of

- action weed management tools not only to preserve yields, but also to maintain the economic and non

- pecuniary benefits realized from using the glyphosate

- tolerant s ystems. Weed resistance is a well understood scientific phenomenon that is not unique to biotechnology or any other form of agriculture. Different herbicides attack weeds by different methods or “modes of action.” The delay that will result from preparatio n of the EISs as proposed by APHIS will deny growers the tools they need to prevent and combat weed resistance and maximize yields through the use of herbicides that have been shown to operate with differing modes of action. The proposed use of these herbi cides in conjunction with the associated herbicide tolerant plants also supports the continued use of environmentally sustainable practices such as no

- till and low

- till farming.

The introduction of soybeans tolerant to 2,4

- D will allow an additional mode of action to be used in the system, allowing for better weed control and harvested soybeans with less foreign material from weed seeds, a valuable characteristic for processors. Oppose preparation of EIS

Soybean growers need new multiple

- mode

of

- acti on weed management tools

Soybeans tolerant to 2,4

- D will allow an additional mode of action

APHIS

- 2013

- 0042

- 0030 Danny Murphy

- American Soybean Association While ASA appreciates concerns about off

- target movement of 2,4

- D, we are confident that farmers have a long history of successfully using proper equipment and application procedures to avoid and minimize off

- target movement of herbicides. Similarly to other herbicide products, off

- site movement of 2,4

- D can be prevented through proper

Page 2

- 30Comment # Comment ID Commenter Comment Excerpt Topic Area steward ship, application techniques, equipment settings and consideration of environmental conditions during application, such as wind speed. ASA is pleased that newer 2,4

- D formulations have been developed to substantially reduce volatility compared to first

gen eration products. We are also pleased that the petitioner has addressed the potential for off

- site movement by prohibiting aerial applications and implementing specific environmental and equipment application requirements on the 2,4

- D label, including a wi nd

directional buffer when sensitive areas are present, and the use of low volatility 2,4

- D formulations. ASA believes that when recommended label practices are followed, farmers of various crops can co

- exist and
prosper. 27 APHIS

- 2013

- 0042

- 0031 Wenonah Hauter

– Food & Water Watch The USDA’s Environmental Impact Statement, must include, at a minimum:

• An analysis on how 2,4

‐ D

‐ tolerant corn and soybeans will facilitate more use of 2,4

- D, leading to the evolution of 2,4

- D

resistant weeds and the abandonmen t of conservation tillage practices;

• Data on the levels of dioxin that will likely be released due to an increase in 2,4

- D use, and the potential cumulative effects on human health and the environment;

• Studies on the effects of increased application of 2,4

- D on surface water quality and impacts on non

- target plants and animals, including endangered species;

• A hard look at how the volatility of 2,4

- D will result in more occurrences of pesticide drift into neighboring fields, affecting plant health and costin g nearby farmers;

• Research on how the ingestion of foods manufactured from these crops will affect human health and how the continued use of the herbicide in agriculture could endanger agricultural workers and the general public; and

• A detailed examination of the cumulative effects of stacking • Herbicide use

• Evolution of 2,4

- D

resistant weeds

• Human health

– ingestion

• Cumulative effects of stacking on cost of contaminatio n and 2,4

- D

and glyphosate

resistant weeds to

non

- GE farmers
Page 2

- 31Comment # Comment ID Commenter Comment Excerpt Topic Area 2,4

‐ D

‐ tolerant corn and soybeans with other herbicide tolerances, including the costs of contamination to non

‐ GE farmers and the costs that 2,4

‐ D and glyphosate resistant weeds will impose on the se growers. APHIS

- 2013

- 0042

- 0031 Wenonah Hauter

– Food & Water W atch USDA’s Environmental Assessments for 2,4

‐ D

‐ tolerant corn and soybeans were inadequate for these genetically engineered traits because they failed to thoroughly cover the cumulative effects that the use of these chemicals under realistic projections. T he chemical treadmill model cannot be continued indefinitely. Weed resistance to these chemicals will continue to abound and the application of more noxious herbicides will increase exponentially. These new corn and soybean varieties are not only unsafe an d inefficient, but are a completely unsustainable solution to the broader problems caused by high

- input production agriculture and associated environmental
pressures. Herbicide use

28 APHIS

- 2013

- 0042

- 0032 Pam Johnson

- National Corn Growers Association USDA has not offered any new scientific reason to justify the decision to prepare an EIS. APHIS identifies two issues for consideration in an EIS, namely possible development of weed resistance and increased herbicide use. However, APHIS’ regulatory author ity is based in the Plant Protection Act and the agency’s oversight is limited to evaluating the potential for the GE plant to pose a plant pest risk. Triggering an EIS based on the justification stated in the Federal Register notice is therefore outside t he scope of APHIS’ jurisdiction. The U.S. Environmental Protection Agency (EPA) has jurisdiction over pesticide use under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). In addition, a recent ruling in the U.S. Court of Appeals for the Nint h Circuit ( Center for Food Safety v. Vilsack , 9th Cir. May 17, 2013) explicitly clarified USDA is not responsible for assessing herbicide use or resistance development under the PPA. Growers need new tools for weed management. With additional modes of acti on, growers will be able to more effectively manage Oppose preparation of EIS

Page 2

- 32Comment # Comment ID Commenter Comment Excerpt Topic Area glyphosate

- resistant and conventional weeds. Based upon APHIS’ assessment, 2,4

- D tolerant corn and soybeans do not pose a plant pest risk. Therefore, USDA should immediately convey nonregulated status on these traits and make them available to U.S. growers. 29 APHIS

- 2013

- 0042

- 0033 Dallas Peterson

- Kansas State

University Department of

Agronomy The ability to effectively control weeds is one of the most important factors in profitable crop production. The use of glyphosate in Roundup Ready crops was a highly cost

- effective approach to weed control for many years, but heavy reliance on glyphosate

- only weed control programs eventually led to the development of glyphosate resistant weeds, including marestail, waterhemp, Palmer amaranth, kochia and giant ragweed, that are difficult to control with current technologies. New technologies such as 2,4

- D tolerant crops would provide an additional tool that could be incorporated into an integrated weed management program to improve overall weed management, including glyphosate resistant weeds. APHIS

- 2013

- 0042

- 0033 Dallas Peterson

- Kansas State

Universi ty Department of

Agronomy The introduction of 2,4

- D tolerant soybeans would likely increase the potential for developing 2,4

- D resistant weeds, but I feel the potential benefits of helping to control existing herbicide resistant weeds far outweighs the ris k of developing 2,4

- D resistant weeds. I also believe the risk of developing 2,4

- D resistant weeds if this technology is introduced is much lower than what has occurred with glyphosate in recent years. Glyphosate plus 2,4

- D is not a viable stand

- alone app roach to successful weed management. Timing is very critical to effective control of most weeds with postemergence herbicides. 2,4

- D needs to be applied to small actively growing weeds for good control. Many problematic weeds, especially waterhemp and P almer amaranth germinate over an extended period of time, so later flushes of weeds will not be controlled by postmergence herbicides like glyphosate and 2,4

- D. Consequently, weed management will be much more successful if postemergence 2,4

- D treatments a re used in conjunction

Page 2

- 33Comment # Comment ID Commenter Comment Excerpt Topic Area with preemergence residual herbicides that can provide extended control. The use of preemergence herbicides as part of an integrated approach has increased in recent years due to the difficulties of controlling glyphosate resistant w eeds and because of the improved commodity prices. Although growers were successful with multiple postemergence applications of glyphosate before the development of glyphosate resistant weeds, I think farmers now realize the many benefits of using a pree mergence herbicide in conjunction with a postemergence treatment. This approach helps minimize potential for early season weed competition and provides more flexibility and better efficacy with the postemergence treatment. The other huge benefit is that b y utilizing more herbicide modes of action, the risk of developing herbicide resistant weeds is greatly diminished. Finally, I believe farmers and crop advisers now realize that relying simply on a single technology such as glyphosate in Roundup Ready
crop s is not a sustainable practice and will eventually lead to the development of herbicide resistant weeds and the loss of an effective tool for weed management. 30 APHIS

- 2013

- 0042

- 0034 Cathleen Enright

- Biotechnology Industry Organization (BIO) In developing its implementing biotechnology regulations under the Federal Plant Pest Act and Plant Quarantine Act, APHIS acknowledged that its oversight of the Introduction of genetically engineered (GE) plants and other organisms would be In accordance with NEPA. The assessment of potential environmental effects has always been an important element of the federal regulatory process for products of biotechnology whether for plants and other organisms under NEPA at APHIS or for pesticides under the Federal Ins ecticide, Fungicide, and Rodenticide Act (FIFRA) at EPA. The basis for the APHIS Notices, however, was not any potential environmental impacts associated with the plants under review. Rather, the Notices identify two issues for consideration In an EIS

- th e potential selection of herbicide resistant weeds and increased herbicide use. As discussed in greater detail herein, the law is clear that potential impacts associated Oppose preparation of EIS

Page 2

- 34Comment # Comment ID Commenter Comment Excerpt Topic Area with herbicide use are EPA's responsibility under FIFRA and are neither subject to APH IS's jurisdiction under the Plant Protection Act (PPA) nor an appropriate basis for preparation of an EIS for an action proposed under the PPA. BIO and its members are also concerned that the decision to prepare EISs for the crops identified by APHIS will unnecessarily delay Issuance of determinations of nonregulated status, causing significant harm to American farmers and the developers of the crops without any additional environmental benefit. APHIS's regulations require a petition for determination of no nregulated status to either be approved in whole or in part or denied within 180 days of the Agency's receipt of the completed petition. Yet, the earliest deregulation petition for the subject crops was filed with APHIS nearly four years ago and declared

c omplete shortly thereafter, and none of the pending petitions for which an EIS would be prepared has yet to be resolved. APHIS estimates completing the two EISs in the summer of 2014 at the earliest, nearly five years after the earliest deregulation petiti on was filed with APHIS and over four years after APHIS's own regulatory deadline. The delay that will result from preparation of the EISs will deny American farmers the new tools they need to prevent and combat herbicide

- resistant weeds and maximize yield s. BIO members have submitted applications to EPA that would authorize use of their herbicides on the associated herbicide tolerant crops identified In the APHIS Notices. These herbicides have differing modes of action, enhancing the ability of growers to address weed problems and supporting the continued use of environmentally sustainable practices such as no

- till farming. Delays inherent in the EIS process will also put U.S. corn, soybean and cotton growers at a particular disadvantage in relation to thei r counterparts in other nations that are now completing their review processes for GE crops on a far more timely basis than the United

Page 2

- 35Comment # Comment ID Commenter Comment Excerpt Topic Area States. In addition, the developers of these crops will suffer further delay in commercializing and offering valuable new products for sale and other developers of Innovative products may reconsider whether to Invest in the U.S. market. Because the APHIS Notices failed to provide a satisfactory legal or scientific justification for opting to prepare an EIS for the subject pr oducts, developers of future products also lack predictability as to whether APHIS will opt to prepare an EA or an EIS, which Significantly affects the deregulation timeline and product development decisions. 31 APHIS

- 2013

- 0042

- 0035 - Agricultural Retailers Association

- American Farm Bureau Federation

- American Seed Trade Association

- American Soybean Association

- American Sugarbeet Growers Association

- Biotechnology Industry Organization

- National Association of Wh eat Growers Our members, who produce the vast majority of commodity crops in America, must be able to utilize the very best available methods to combat weed resistance problems. Weed resistance is a well understood scientific phenomenon that is not unique to biotechnology or any other form of agriculture. Different herbicides attack weeds by different methods or “modes of action.” The delay that will result from preparation of the EISs as proposed by APHIS will deny growers the tools they need to prevent and combat weed resistance and maximize yields through the use of herbicides that have been shown to operate with differing modes of action. The proposed use of these herbicides in conjunction with the associated herbicide tolerant plants also supports the continued use of environmentally sustainable practices such as no

- till and low

- till farming. Additionally, the delays inherent in the EIS process proposed by APHIS will put American growers at a fu rther disadvantage to corn, soybean and cotton growers in other nations that are now completing their review processes for biotechnology

- derived crops on a far more timely basis than the United States. Any further delay is unacceptable, particularly when A PHIS’s own regulations require APHIS to respond to a petition for determination of nonregulated status within 180 days of the Agency’s receipt of the petition. 7 C.F.R. § 340.6(d)(3). Oppose preparation of EIS

Page 2

- 36Comment # Comment ID Commenter Comment Excerpt Topic Area

- National Corn Growers Association

- National Cotton Council Our members support a science

- based, federal environmental review
proces s for new agricultural biotechnology products. The Notices of Intent issued by APHIS, however, identify two issues for consideration in an EIS (i.e., weed resistance and increased herbicide use), both of which are subject to the sole jurisdiction of the U. S. Environmental Protection Agency (“EPA”) under the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”). These pesticide issues are unequivocally not subject to APHIS’s jurisdiction under the Plant Protection Act. 32 A PHIS

- 2013

- 0042

- 0036 Dow Agrosciences, LLC (DAS) DAS supports a science

- based, federal environmental review process for those products. That process must of necessity recognize that the crops and herbicides are subject to the jurisdiction of two different

r egulatory agencies operating under their own independent statutory mandates and differing environmental review standards. DAS is concerned that APHIS's planned preparation of an EIS for the determinations of nonregulated status requested by DAS for its her bicide tolerant crops fails to recognize these distinctions. Moreover, the EIS preparation process contemplated by APHIS will unnecessarily delay issuance of determinations of nonregulated status (deregulation) for these crops resulting in irreparable harm to farmers and DAS with no additional benefit to the environment. Indeed, delays inherent in the EIS preparation process will likely force many com and soybean growers to use less sustainable weed management practices resulting in soil runoff and other ad verse environmental effects. Most significantly, these delays will deny growers the new tools they need to combat weeds and maximize yields. Weed resistance is a well understood scientific phenomenon that farmers must manage. 1 It is not unique to biotechn ology or any other form of agriculture. Different herbicides attack weeds by different methods or "modes of action." Reliance on a single herbicide and its unique mode of action is certainly a contributor to development of weed resistance. The applications submitted to EPA by DAS and other Oppose preparation of EIS

Page 2

- 37Comment # Comment ID Commenter Comment Excerpt Topic Area companies for use of their herbicides with the associated herbicide tolerant crops are intentionally designed to provide growers with herbicides that act by different modes of action, significantly enhancing growers' abil ity to address weed problems, increase yields and maintain environmentally preferable, no

- till and low

- till agricultural practices. Delays inherent in the EIS process will also place U.S. growers at a further disadvantage to com, soybean and cotton growers in other nations that are now completing their regulatory reviews for biotechnology

- derived crops on a far more expedited basis than the United States. Finally, the decision to prepare a EIS will also be costly to DAS, forcing the company to continue prod ucing seed under the burdensome APHIS permitting process, in addition to suffering a further delay in commercializing and offering its new herbicide tolerant crops for sale. For all of these reasons DAS objects to the preparation of an EIS for deregulation of its crops. 33 APHIS

- 2013

- 0042

- 0037 Rachel Lattimore, Senior Vice President, General Counsel, Secretary

- CropLife America On May 16,2013, APHIS published in the Federal Register notices announcing its intention to conduct Environmental Impact Statements (EISs) related to several new technologies: dicamba tolerant soybeans, dicamba tolerant cotton, 2,4

- D tolerant corn, and 2,4

- D tolerant soybeans. 1 APHIS's declared intent to conduct these EISs focuses solely on pesticide issues regulated by the United States Environmental Protection Agency (EPA). We strongly urge you to reconsider the need for EISs for these technologies due to clear limitations on APHIS's Congressional mandate and in light of a recent ruling by the Ninth Circuit Court of Appeals clarifying EPA and APHIS's respective jurisdictions in this area. 2 The proposed EISs would introduce unnecessary regulatory redundancy and potential regulatory confusion by analyzing the proposed use of herbicides that are under active review by EPA and outside the jurisdictional purview of APHIS. Congress's well

- established distribution of regulatory authority over Oppose preparation of EIS

Page 2

- 38Comment # Comment ID Commenter Comment Excerpt Topic Area agricultural technolo gies and recent Ninth Circuit case law establish that APHIS's proposed EISs are unnecessary, redundant, and potentially in conflict with EPA's authority. In light of these concerns and the substantial cost and delay that would be incurred due to such a

rev iew, CropLife America strongly urges APHIS to reconsider its decision to conduct these EISs. 34 APHIS

- 2013

- 0042

- 0038 Steve Smith, Chairman

- Save Our Crops Coalition We urge the granting of approval for the Dow 2,4 D Enlist TM syst em but maintain grave concerns (as addressed in comments specifically on the dicamba petition) about the widespread use of dicamba on the environment, which prompted our original petition. Monsanto continues to promote practices that will be of great envi ronmental risk if widespread use of dicamba is approved without the reasonable restrictions that Dow recognized and implemented. Support approval of Dow petitions

35 APHIS

- 2013

- 0042

- 0039 Joyce Dillard We request that more thorough studies occur on bees and colony collapse, birds and the watershed ecosystems as well as viruses that spread through migration related to watershed ecosystem connectivity. Water contamination is a problem in a watershed not necessarily in the vicinity of the crops, so all avenu es need to be studied. The liabilities of the Clean Water Act should not be placed on other watershed systems. Herbicide use

36 APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Policy

- WSSA Science has clearly shown that there is a risk of resistan ce development to all herbicides, and 2,4

- D and dicamba are no exception. In fact weeds have evolved resistance to nearly all forms of weed control including herbicides, tillage, mowing and hand weeding. Some of our members have voiced concerns that grower s may adopt 2,4

- D and dicamba technologies and rely too heavily on these herbicides thereby developing an even greater weed resistance situation. However, the majority of our member scientists view 2,4

- D and dicamba resistant crops as an additional weed ma nagement tool to include in an integrated weed management program. The greatest risk for developing herbicide resistance is actually occurring right now with the PPO herbicides and glufosinate. These products are being over

- used in

Page 2

- 39Comment # Comment ID Commenter Comment Excerpt Topic Area certain cropping systems as farmers have no other effective herbicide options. The 2,4

- D and dicamba resistant crops could be used to delay resistance development to the PPO herbicides and glufosinate and, in turn, weed management systems could be developed using the PPO herbicid es, glufosinate, 2,4

- D and dicamba, extending the life of each of these chemistries. APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Polidy

- WSSA Weed management is ultimately the responsibility of farmers and farm advisors. However, the weed science community, including industry, academics, crop commodity groups and others who reach out to farmers, must recommend robust and effective stewardship programs espousing the basic principles of good weed management and encourage adoption of these pra ctices. By doing so, evolution of resistance to our herbicide resources and new options such as 2,4

- D and dicamba resistant crops will be minimized. APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Polidy

- WSSA Research indicates that 2,4

- D and d icamba will fit best in a fully diversified program and such a program is particularly important when glyphosate resistant palmer pigweed and waterhemp are the targets. APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Polidy

- WSSA Resistance to 2 ,4

- D and dicamba represents no more a threat to agricultural production than resistance to other critical herbicides and the likelihood that it will be used in a manner consistent with best management practices is good. APHIS

- 2013

- 0042

- 0040 Lee Van Wyc hen, Director Science Polidy

- WSSA Stacking 2,4

- D and dicamba tolerance with that of glyphosate, glufosinate, and other herbicide tolerant traits will further facilitate the use of these herbicides in a diversified program. Stacking herbicide traits does not in itself promote the evolution of resistance to more than one herbicide since, just as for individual herbicides, the evolution of resistance is a function of how the herbicides are used rather than a function of the selectivity of the crop to multip le herbicides. APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Polidy

- WSSA The ability of farmers to use 2,4

- D and dicamba in diversified weed management programs in soybeans, corn, and cotton is not expected to significantly change current far ming practices. These herbicide tolerant crops will, however, provide valuable new postemergence options that

Page 2

- 40Comment # Comment ID Commenter Comment Excerpt Topic Area will allow farmers to most effectively manage their weeds when practicing conservation tillage even in the presence of glyphosate resistant popula tions. Farmers have clearly shown a preference for postemergence weed control in conservation tillage systems and 2,4

- D and dicamba can be an important part of this system.

As the spread of glyphosate

- resistant weeds occurred, the adoption of tillage, in cluding deep tillage with a moldboard plow has once again become more common. The return of conventional tillage has led to increased wind and water erosion. Neither 2,4

- D nor dicamba technologies would eliminate tillage, but they would greatly reduce the need for deep tillage allowing many farmers to return to more reduced tillage production systems. APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Polidy

- WSSA New and expanded uses of existing herbicides are needed for integrated weed management programs in order to mitigate weed resistance and meet our current and future crop production needs. APHIS

- 2013

- 0042

- 0040 Lee Van Wychen, Director Science Polidy

- WSSA Off target movement of 2,4

- D and dicamba pose the greatest limitation to the adopt ion of either auxin technology. An enormous amount of research by the registrants and other weed scientists around the world has been conducted to develop methods to minimize the potential for off

- target movement. These efforts include 1) improving herbici de formulations, thereby reducing volatility and/or drift, 2) improving application equipment techniques and application methods, thereby reducing drift, and 3) developing educational materials to assist growers in reducing off target movement when making pesticide applications. There is no question these research efforts will greatly minimize off

- target movement of all pesticides, not just 2,4

- D and dicamba, and will greatly improve the ability of a grower to apply pesticides that stay in the targeted area

. Herbicide use

- drift

37 APHIS

- 2013

- 0042

- 0041 Kenneth Isley, Vice President, General Counsel, Secretary

- Dow AgroSciences LLC ("DAS") respectfully submits this petition to the United States Department of Agriculture ("USDA") , Animal and Plant Health Inspection Service ("APHIS"), amending and requesting

Page 2

- 41Comment # Comment ID Commenter Comment Excerpt Topic Area Dow Agrosciences, LLC (DAS) that APHIS immediately grant DAS's pending petitions for determination of nonregulated status for DAS

- 40278

- 9 Corn (Petition No. 09

- 233

- 01 p), DAS

- 68416

- 4 Soybean (Petition No. 09

- 349

- 0lp), and DAS

- 44406

- 6 Soybean (Petition No. 11

- 234

- 01 P ) (collectively, the ''EnlistTM Plants"). See 7 C.F.R. § 340.6(a). Under the unique circumstances presented here, DAS respectfully requests that APHIS: • immediately grant DAS's pending petitions for determination of nonregulated status for the Enlist TM Plants; and • immediately reconsider and withdraw its decision to prepare an EIS as to the Enlist TM Plants and terminate the NEPA process. APHIS's unwarran ted delay in the issuance of determinations of nonregulated status for the Enlist TM Plants has caused and will continue to cause significant harm to American farmers and DAS. This harm will be especially acute, and irreparable, in the event that determinati ons of nonregulated status are not issued before the fall 2013 harvest. Thus, DAS respectfully requests that APHIS respond to this petition within the next thirty (30) days, by July 18, 2013. 38 APHIS

- 2013

- 0042

- 0042 Center for Food Safety Copy of comment s submitted to USDA

- APHIS under Docket No APHIS

‐ 2012

‐ 0019 (DAS 68416

- 4 soybean)

– Comments to USDA APHIS on Draft Environmental Assessment and Draft Plant Pest Risk Assessment for Dow AgroSciences Petition (09

- 349

- 01p) for Determination of Nonregulated Status of Event DAS

- 68416

- 4: 2,4

- D

- and glufosinate

- resistant soybean Attachment APHIS

- 2013

- 0042

- 0043 Center for Food Safety Copy of comments submitted to U.S. EPA

- Comments to EPA on Notice of Receipt of Applications to Register New Uses of 2,4

- D on Enlist TM AAD

- 1 Corn and Soybean 39 APHIS

- 2013

- 0042

- 0044 Center for Food Safety Copy of comments submitted to USDA

- APHIS under Docket No APHIS

‐ 2012

‐ 0103 (DAS

- 40278

- 9 corn) 40 APHIS

- 2013

- 0042

- 0045 Center for Food Safety 2,4

- D

- resistant crops must be viewed as weed control systems In preparing the EIS, APHIS must assess 2,4

- D

- resistant corn and

Page 2

- 42Comment # Comment ID Commenter Comment Excerpt Topic Area soybeans as crop systems comprising the herbicide

- resistant crop itself and associated use of 2,4

- D. Monsanto describes its Round up Ready (RR) crops as RR crop systems. Dow describes 2,4

- D

resistant crops as the “Enlist TM weed control system.” “System” is defined as “a set or arrangement of things so related or connected as to form a unity or organic whole,” 1 meaning there is no need for elements not encompassed by the system to accomplish its purpose. Exclusive or near

- exclusive use of glyphosate as the sole weed control measure with Roundup Ready crop systems is a major factor in the epidemic of glyphosate

- resistant in U.S. agricult ure. A similar dynamic will be in play with 2,4

- D

- resistant crop systems, so they must be assessed as systems. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Impacts of 2,4

- D

- resistant crop systems on herbicide use For all practical purposes, 2,4

- D

- resistant corn and soybeans eliminate the severe biological constraints on use of this herbicide with all other types of corn and soybeans ever developed or grown. Label rates of 2,4

- D coincide roughly with rates that begin to cause crop damage, and the imperative to avoid crop damage is as or more effective than the label in keeping 2,4

- D use within bounds. Once the crop injury constraint is lifted, there is no biological reason for the farmer to follow the label. From a modestly used pre

- ‐ emergence he rbicide in soybeans and early POST herbicide in corn, 2,4

- D will become one of the major herbicides for weed control in Enlist TM crop systems (likely with additional use of glyphosate, ACCase inhibitors and/or glufosinate if stacked with resistance to these herbicides). APHIS must assess the shift in 2,4

- D use patterns to be expected in various crop adoption scenarios. APHIS should assess both the change in amount applied, per acre per crop, and the shift in use pattern (i.e. amount used
pre

- emergence vs. po st

- emergence). APHIS should also assess the impact of 2,4

- D crops on overall herbicide use, keeping in mind that 2,4

- D would likely displace little if any glyphosate, which has a broader spectrum of activity, including (unlike 2,4

- D) activity on grass

Page 2

- 43Comment # Comment ID Commenter Comment Excerpt Topic Area fami ly weeds. We refer APHIS to our comments, where CFS makes such projections. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Features of HR crop systems that promote HR weeds As discussed in our comments, HR crop systems promote not only (near

- ) exclusive r eliance on the associated herbicide(s), but also more frequent use over a broader application window that extends much further into the crop season than would otherwise be possible. Resistant weeds with Roundup Ready crops are too often treated superficial ly as simply the result of excessive glyphosate use, but as Paul Neve has pointed out, the post

- emergence use pattern of glyphosate with RR crops is another, independent factor promoting weed resistance, beyond exclusivity and frequency of glyphosate use. In other words, the timing as well as the exclusivity and frequency of herbicide use is a factor in promoting weed resistance. In practice, applications are often made late post

- emergence to larger weeds, increasing resistance risks still more. Additional evidence comes from weed resistance to ALS inhibitor herbicides, many of which were and are used post

- emergence. ALS inhibitor

- resistant weeds arose in 1987 just five years after the first ALS inhibitor herbicide was introduced, and became extremely preval ent in less than a decade; in fact, by undermining the efficacy of widely used ALS inhibitors (especially in soybeans), resistant weeds provided much of the impetus for adoption of RR crops (as a means to kill ALS inhibitor

- resistant weeds), just as glypho sate

- resistant weeds have become the rationale for 2,4

- D

resistant crop systems. We emphasize that while a post

- emergence herbicide use pattern is certainly not a necessary condition for weed resistance to evolve (e.g. atrazine used primarily pre

- emergence and early post

- emergence in corn led to substantial weed resistance), it does appear to be a facilitating factor where present. APHIS must assess the post

- emergence weed control paradigm that is a central feature of HR crop systems for its resistance

- prom oting potential in the case of 2,4

- D

- resistant crops and weeds, in addition to the more

Page 2

- 44Comment # Comment ID Commenter Comment Excerpt Topic Area obvious factors of exclusivity and frequency of use. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Socioeconomic factors associated with HR crops and HR weeds As discu ssed in our comments, pricing strategies influence farmer weed management decisions in such a way as to contribute to evolution of weed resistance. Companies charge fees for HR traits that are substantial enough to create a strong incentive for the farmer to make full use of the trait(s) through total reliance on the associated herbicide(s). APHIS should find or develop studies that explore the extent to which pricing strategies for HR crop systems (e.g. high

priced seed, low

- cost herbicide) reinforce herbi cide use patterns that foster resistance in the case of 2,4

- D

- resistant corn and soybeans. RR crops’ major and closely intertwined “benefits” are reduced labor needs for weed management (at least until resistant weeds emerge) and the simplicity of glyphos ate

- only weed control. In addition, glyphosate’s superior ability to control large weeds relative to other herbicides broadens the application window for acceptable weed control. These factors together facilitate increased farm size, since more land can be managed for weeds with the same labor, and labor needs for weed control are a major limiting factor on farm size. One can expect 2,4

- D

- resistant crops to have similar impacts. APHIS should assess the socioeconomic consequences of 2,4

- D

- resistant corn and soybeans, in terms of increased land and rental prices from increased competition for land, increased average size of farms, and accelerated exit of small

- to medium

- size farmers from agriculture. APHIS

- 2013

- 0042

- 0045 Center for Food Safety HR crops and drift damage HR crop systems entail a pronounced shift in herbicide use to much later in the season when neighboring crops have leafed out and are more vulnerable to drift damage (from early season herbicide use when drift poses much less risk). Glypho sate has become a leading cause of drift damage in the era of Roundup Ready crops, despite the fact that it is not a volatile or drift

- prone herbicide. This is not merely because its use has increased so dramatically, but also because its use has shifted

Page 2

- 45Comment # Comment ID Commenter Comment Excerpt Topic Area h eavily to later in the season. 2,4

- D is much more volatile than glyphosate, and is particularly prone to vapor drift. APHIS must comprehensively assess the increased drift damage that would occur with various 2,4

- D

- resistant corn and soybean adoption scena rios, both in terms of lost yield and income, broken down by major crop (e.g. soybeans, cotton) or crop category (e.g. vegetables). APHIS should further assess the extent to which 2,4

- D

- resistant crop adoption would reduce plantings of susceptible crops (e .g. vegetables, grapes) and/or shift acreage to 2,4

- D

- tolerant crops that could withstand drift level doses (e.g. corn). In conducting this assessment, APHIS must account for the inevitable use of more drift

- prone 2,4

- D formulations (e.g. because likely t o be cheaper than the choline salt), and not presume an ideal world scenario where only potentially less drift

- prone formulations are used. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Crop volunteers resistant to 2,4

- D, ACCase inhibitors, glyphosate, g lufosinate, etc. as weeds RR crop volunteers have been repeatedly noted as problematic weeds, particularly corn, but also cotton and soybeans; and particularly where RR crops are rotated (see comments). SmartStax corn is even more problematic, since glufos inate as well as glyphosate are eliminated as control options. APHIS must assess the increased weediness of volunteers of corn and soybeans resistant to 2,4

- D, ACCase inhibitors, glyphosate, and/or glufosinate. Further, since cross

- pollination with other p rospective herbicide

- resistant cultivars will be possible (e.g. dicamba

- resistant corn), APHIS should consider scenarios with volunteers that have stacked resistance. The assessment should include increased costs of control, increased use of herbicides, in creased weed resistance risks from a narrowing of herbicidal control options and increased reliance on those (few) herbicides still effective. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Interplay between HR traits and Bt resistant pests 2,4

- D

- resistan t corn will be offered mainly in stacks with Bt traits. Research described in the 2,4

- D comments shows that HR corn

Page 2

- 46Comment # Comment ID Commenter Comment Excerpt Topic Area volunteers produce lower levels of Bt toxin and thereby promote Bt resistance in corn rootworm; the more HR traits in the corn volunteers,
t he less likely they will be managed adequately, and hence the more likely they will contribute to Bt resistance. See discussion in 2,4

- D

comments. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Cross

- resistance between 2,4

- D, dicamba and other synthetic auxin herbicides In our comments, we discuss evidence that certain weeds resistant to 2,4

- D (e.g. waterhemp) also exhibit increased tolerance to dicamba; and that dicamba

- resistant crops have increased tolerance to chlorophenoxy herbicides like 2,4

- D. In view of their common mechanism of action, these findings strongly suggest the potential for evolution of cross

- resistance in weeds to dicamba and phenoxy herbicides. Most weed biotypes resistant to either dicamba or 2,4

- D have no t been tested for resistance to the other. APHIS must assess the potential for 2,4

- D crop systems to foster resistance, not only to 2,4

- D, but also to dicamba, and the impacts such cross

- resistant weeds (against a background of resistance to glyphosate, A LS inhibitors and/or other herbicides), would have on weed control in soybeans, corn and other crops. Known weed biotypes with resistance to either 2,4

- D or dicamba should be tested for tolerance to the other, to help establish the potential for such cross

- resistance. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Non

- target effects of 2,4

- D

- resistant crops Roundup Ready crop systems have dramatically increased use of one of the most effective plant

- killing compounds ever developed. Glyphosate is particula rly noted for its efficacy against perennial weeds, which most other herbicides have difficulty controlling. Glyphosate use with Roundup Ready crops is a major factor in the dramatic decline in Monarch butterfly populations over the past two decades (see 2 ,4

- D

- resistant soybean comments to USDA). Glyphosate has decimated milkweed populations in Midwest corn and soybean fields; and milkweed in such fields is the major breeding ground for

Page 2

- 47Comment # Comment ID Commenter Comment Excerpt Topic Area migratory Monarchs that overwinter in Mexico. APHIS must project the im pact of 2,4

- D

- resistant corn and soybean systems (with additional resistance to glyphosate and/or glufosinate) in further reducing populations of milkweed in agricultural fields and thus exacerbating the decline in Monarch populations. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Many glyphosate formulations are extremely toxic to various species of frogs. Massive glyphosate use accompanying Roundup Ready crops has been posited as a likely factor in the global decline of amphibian populations. APHIS must assess the impacts of 2,4

- D

- resistant corn and soybean systems (with additional resistance to glyphosate and/or glufosinate) on amphibian populations. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Impact of HR crop systems on sustainable weed control Please assess the impact that Roundup Ready crop systems have had on efforts to advance adoption of sustainable weed management techniques (e.g. crop rotation, cover crops); and based on this analysis, similarly project the impacts that 2,4

- D

- resistant cro ps (with additional resistance to ACCase inhibitors, glyphosate and/or glufosinate) would have on the same. APHIS

- 2013

- 0042

- 0045 Center for Food Safety Health impacts of increased 2,4

- D use with 2,4

- D

- resistant crop systems Medical scientists have found 2,4

- D use associated with increased risk of non

- Hodgkin’s lymphoma and other adverse human health impacts (for discussion see human health section of 2,4

- D comments to EPA). Dioxins continue to contaminate 2,4

- D, and EPA has failed to collect comprehensi ve, independent data on the dioxin content of the many 2,4

- D formulation used by farmers. CFS projects a many

- fold increase in use of 2,4

- D with introduction of either or both 2,4

- D crop systems, and thus a further increase in exposure to and disease from this toxic herbicide. APHIS and EPA must assess the increased incidence of disease to be expected with the substantial increase in 2,4

- D use accompanying introduction of these crop systems. Human health

– 2,4

- D use

APHIS

- 2013

- Center for Food 2,4

- D

- resistant crops and tillage 2,4

- D

- resistant

Page 2

- 48Comment # Comment ID Commenter Comment Excerpt Topic Area 0042

- 0045 Sa fety Roundup Ready crops have not, as popularly imagined, fostered increased use of conservation tillage. The major gains in conservation tillage adoption came in the 1980s and early 1990s, in consequence of 1985 and 1990 Farm Bill provisions that tied subsidies to use of soil

conserving practices. In fact, adoption of conservation tillage actually stagnated in the decade of Roundup Ready crop adoption. Instead, the glyphosate

- resistant weeds generated by RR crop systems ha ve led to increased tillage for weed control and hence greater soil erosion. CFS has presented a detailed analysis to support these conclusions in the 2,4

- D

- resistant soybean comments. APHIS must assess the potential for 2,4

- D crop systems to further incre ase soil erosion through increased use of tillage to control the 2,4

- D

- resistant weeds that will be generated by these crop systems. weed development

– impacts on tillage and soil erosion

APHIS

- 2013

- 0042

- 0045 Center for Food Safety APHIS should also require the applicants to supply information necessary for meaningful risk assessments that is not in their petitions, or better yet undertake appropriate research to fill in the gaps. For example, the following information should be available for review by APHIS and the public:

• Proposed herbicide application regime: how much herbicide, how often, window of application.

• Degree of resistance conferred by the transgene in different plant parts and stages of development.

• Expression of the transge ne in pollen, nectar; levels of herbicide residues and metabolites in pollen, nectar.

• Herbicide residues and metabolites in plant tissues from the time of application through post

- harvest. APHIS

- 2013

- 0042

- 0045 Center for Food Safety APHIS needs to ana lyze the following areas:

• Agricultural production impacts, including and not limited to burden on organic and non

- transgenic agricultural production and potential harms to non

-- ‐ target crops from the adoption of the HR crop system.

• Environmental impacts, including but not limited to: Page 2

- 49Comment # Comment ID Commenter Comment Excerpt Topic Area

- Herbicide use and changes in herbicide use patterns;

- Gene flow from 2,4

- D

- resistant corn and soybeans to compatible varieties and the resulting increased weediness;

- Agricultural practices, including herbicide use, effects on
t illage; and

- Weed resistance and volunteers.

• Socioeconomic impacts, such as:

- Transgenic contamination and their effects on both domestic and export markets, as well as, consumers and farmers’ right of choice

- Changes in seed industry market concentration an d their impacts,

- Effects on the methods and costs of weed control

• Human health impacts, such as:

- Herbicide use, including impacts on farm workers; and

- Safety of food products

• Livestock health, such as:

- Herbicide use; and

- Safety of animal feed.

• Threatened and endangered species, such as:

- Herbicide use; and

- Quality of crop tissues as food sources.

• Disease and pest impacts stemming from 2,4

- D

- resistant soybeans and corn and the associated herbicide use. 41 APHIS

- 2013

- 0042

- 0046 Center for Food Saf ety Comments to USDA APHIS on Environmental Assessment for the Determination of Nonregulated Status of Herbicide

‐ Tolerant DAS

‐ 40278

- 9 Corn , Zea mays , Event DAS

‐ 40278

‐ 9

- Center for Food Safety, Science Comments II

See Comment Summary for DEA for DAS

- 40278

- 9 Corn Attachment APHIS

- 2013

- 0042

- 0047 Center for Food Safety Comments to USDA APHIS on Draft Environmental Assessment and Draft Plant Pest Risk Assessment for Dupont

- Pioneer’s Petition (11

- Page 2

- 50Comment # Comment ID Commenter Comment Excerpt Topic Area 244

- 01p) for Determination of Nonregulated Status of I nsect

- Resistant and Herbicide

- Resistant Pioneer 4414 Maize: Event DP

- 004114

- 3

Page 2

- 51Table 2

- 2

. Public Scoping Comments Submitted During Virtual Public Meeting Commenter Affiliation Concern/Issue June 26, 2013 Ray Gaesser grower and First Vice President of the American Soybean Association They [2,4

- D and dicamba] will allow us, on our farm at least, to continue to no till. If we don't have those products, we may have to go back to tillage to deal with some o f the weeds that we have. Agronomic practices

We use them [2,4

- D and dicamba] on our farms. I've been farming 25 years now, and I've had experience using both of those products in a different formulation for all that time. And, really, I've never had any problems with it, (static

- cell interference) response to our own crop or our neighbor's. As the previous speaker said, we are tested in Iowa. As is required of all of our applicators that come from the co

- ops and from the industry, are tested, and un derstand the need and the right way to apply herbicides. Herbicide use

We used to use a lot of those products, and now with glyphosate, we use less in order to address the issues of weed resistance in particular, and the real need for multiple modes of actions. All of our universities are saying that we need multiple modes (indiscernible) of action to avoid weed resistance. So I would urge you to move forward with both of these applications. Herbicide use

David Shaw Past President, Weed Science Society of America (WSSA) Biotechnology has allowed us to maximize yields in economics, to be able to mitigate the potential development of herbicide resistance, and to be able to effectively gain tremendously with the development of conservation tillage practices in the United Sta tes. N/A

Herbicide resistance has developed substantially over the last few years, but is not a new phenomenon. In fact, it has been recorded and noted for over 40 years

now. Herbicide

- resistant weeds

Page 2

- 52Commenter Affiliation Concern/Issue One of the primary practices that we scientists recommend in managing proactively herbicide resistance is the ability to use a wide diversity of mechanisms of actions with different herbicides that affect plants in different ways. We need more herbicide options to be able to manage these and to be able to preserve the utility of those that we already have. The ability to effectively use dicamba and 2,4

- D in soybean and cotton will help fill this critical need.

We have seen the development of herbicide resistant plants most notably in the last few years with glyphosate resistance in (indiscernible) crops. This problem has become widespread, in several of our major commodities. And dicamba and 2,4

- D, also the ability to use a different mechanism of action than what is currently available in these crops to be able to more effectively and proactively mitigate and delay the evolution of herbicide resistance. There are a number of factors that come into play in the evolution of herbicide resistant weeds and crops. However, we scientists understand that this is a function of managing the practices and the herbicides that are available for weed management. It is as such not a plant biotechnology issue. It is a use of the technology and the rotation and a development of an overall plan using various management practices that have been identified.

Weed management is ultimately the responsibility of farmers and farm advisors that requires the entire community of weed scientists, industry, academia, crop

Page 2

- 53Commenter Affiliation Concern/Issue commodity, and others to be able to effectively steward herb icide resistance management. By using the development of resisted crops that have the tolerance to dicamba and 2,4

- D, this represents no greater threat than the development of any herbicide technology that has hurt in the past. It is also noted that on e of the major challenges that we have with the development of herbicide resistance is the losses that we are now experiencing in conservation tillage acres. Dicamba and 2,4

- D tolerance will certainly allow us to help preserve these valuable gains and the preservation of our soils in the United States.

Page 2

- 54

### Weed Management and Herbicide Use Appendix 3.

Page 3

- 1Weed Management and Herbicide Use

Weed control programs are important aspects of corn and soybean production intended to prevent the establishment of plants other than the intended crop. In crop production systems, these plants, identified as weeds, are controlled using a number of tactic s to maximize the production of food, fiber, and fuel ( Green and Martin 1996 ) . The goal of weed management is to reduce weed populations, allowing for more efficient use of herbicides and other cultural practices to control weeds.

Each field has a finite amount of resources, i.e., light, nutrients, and moisture, available for the growth and developm ent of crops. Weeds allowed to compete with crops can ultimately result in crop yield loss. Once the critical period of weed control (CPWC) has been reached, if weed control is delayed, the yield loss can increase fairly rapidly. Knezevic concluded that delaying the time of weed removal after the starting point of CPWC will cost corn and soybean producers an average of 2% in yield lo ss per every leaf stage of delay ( Knezevic, Evans et al. 2003 )

. According to Iowa State University research, uncontrolled weeds of 3

- 4 inches in corn at the V

- 3 to V

- 4 growth stage have been shown to decrease yields b y about 3 bushels per acre per day ( Rosenberg 2013 )

. Weeds species present varying degrees of competitiveness. Table 3

- 1 shows the potent ial yield losses associated with specific weed species present at two different densities. The impacts to yield are based on normal weather conditions and adequate soil moisture and assume that the weeds emerged with the crop. Crops under drought conditio ns or other stresses may have higher yield losses. According to the data, at higher densities annual broadleaf weeds impact yields more than annual grasses ( Ontario Ministry of Agriculture and Food 2009 )

.
Table 3

- 1

. Soybean and Corn Yield Losses Due to Weeds at Known Populations

Weed Percent Yield Loss (%) Corn Soybean (1 plant/m 2 ) (5 plants/m 2 ) (1 plant/m 2 ) (5 plants/m 2 ) Annual Broadleaves Giant ragweed 13 36 14 40 Lamb's

- quarters 12 35 13 38 Pigweed 11 34 12 36 Cocklebur 6 22 15 41 Ragweed 5 21 10 33 Wild mustard 5 18 5 18 Velvetleaf 4 15 4 15 Lady's thumb 3 13 4 15 Wild buckwheat 2 10 4 15 Eastern black nightshade 1 2 7 14 40

Annual Grasses Giant foxtail 2 10 3 12

Page 3

- 2Weed Percent Yield Loss (%) Corn Soybean (1 plant/m 2 ) (5 plants/m 2 ) (1 plant/m 2 ) (5 plants/m 2 ) Proso millet 2 10 3 12 Fall panicum 2 10 2 10 Barnyard grass 2 7 3 12 Green foxtail 2 7 2 8 Yellow foxtail 1 5 1 5 Old witch grass 1 5 1 4 Crabgrass 1 3 1 4 Volunteer corn

-- -- 4 15

1 Eastern black nightshade in soybeans reduces its quality. Note: Crop losses assume that the weeds have emerged with the crop. Adapted from www.wedpro75.com ( Ontario Ministry of Agriculture and Food 2009 )

Yield loss information on weed s at different weed and crop growth stage is available through the use of the WeedSOFT TM yield loss calculator ( see http://weedsoft.unl.edu , click on “tools

calculators ”) ( Weed Soft 2013 )

. The degree of yield loss for a crop can be related to:

• Environmental conditions (e.g., temperature, moisture, etc.),

• The distribution of weed species within a given field;

• Weed density; and

• The timing of weed emergence (i.e., weed height) relative to the crop growth stage ( Knezevic 2007 )

. Therefore, weed management programs should not only focus on minimizing weed density and yield reductions, they sh ould also include approaches to minimize weed seed banks. Eliminating weeds before seed production diminishes contributions to the weed seed bank and provides the best assurance for improving future weed management.

Weed control programs vary by crop, we ed problem, geography, and cropping system (e.g. no

till, conventional

- till, etc.). Many growers use a combination of weed control techniques including cultural, mechanical, and chemical. Practices that establish a dense, vigorous crop canopy quickly (e.g. higher seeding rates, optimum soil fertility, proper seedbed preparation, seeding depth) provide competition to smother weeds.

The keys components to successful weed management are:

• Knowing the exact identity of all weeds in the field;

• Treating (if nec essary) while the weeds are small;

• Tailoring control measures to the type of weed and its size ( Linker, Coble et al. )

.

Page 3

- 3Although weed control typically involve s an integrated approach that includes herbicide use, crop rotation, weed surveillance, and weed monitoring ( Farnham 2001

, IPM 2004
, IPM 2007
, Hartzler 2008

, U niversity of California 2009 ) , currently, herbicides are the most common and efficient tactic to manage weeds within agroecosystems ( Gianessi and Reigner 2007 )

. Various strategies utilized for weed managem ent are discussed in the following sections.

Chemical Control

- Herbicides

Herbicides are chemicals that move into a plant and disrupt vital biological process. Herbicides have been the primary tactic used to manage weed communities in corn and soybean sin ce the mid

- 1960s and will continue to be an important feature of row crop weed management for the foreseeable future. One study, which examined aggregated data on crop yield losses and herbicide use, estimated that even if additional tillage and hand weed ing labor replaced the use of herbicides, U.S. crop production would decline by 20 percent with a $16 billion loss in value if herbicides were not used ( Gianessi and Reigner 2007 ) . Herbicide use is not regul ated by APHIS but rather by EPA under FIFRA and its amendments.

Before selecting a herbicide program, growers should know what weeds are present or expected to appear, the soil texture and organic matter content, capabilities and limitations of the various herbicides, and how to best apply the herbicides ( York and Culpepper 2000 )

. Additionally, when selecting an herbicide, a grower must consider, among other factors, whether an herbicide can be used on the crop (herbicides are registered by EPA for specific uses and crops), potential adverse effects on the crop, residual effects that can limit crops that can be grown in rotation, effectiveness on expected weeds, and cost.

To be effective, herbicides must (1) adequately contact plants, (2) be absorbed by plants, (3) move within the plants to the site of action without being deactivated, and (4) reach toxic levels at the site of action ( Penn State Extention 2013 )

. Herbicides are classified according to their effects on plants as either selective or nonselective. Selective herbicides will kill weeds without significant damage to desirable plants. Nonselective herbicides kill or injur e all when applied at an adequate rate ( Penn State Extention 2013 )

. Herbicide action is either contact or systemic. Contact herbicides kill only plant tissue contacted by the chemical. Systemic herbicides are absorbed from the point of application, either the roots or foliage, and move within the plant to other plant p arts. Systemic herbicides may be effective against both annual and perennial weeds, but are particularly effective for control of established perennial weeds. However, systemic movement of an herbicide in perennial weeds can vary seasonally ( NC State Univer sity 1998 )

. Applications of herbicides to a crop or weed are described acc ording to when they are applied:

• Pre

- plant (i.e., burndown): applied to soil before the crop is planted. For p re

- plant incorporated, herbicides are applied to soil and mechanical ly incorporated into the top 2 to 3 inches of soil before the crop is planted. In burndown, generally herbicides are used in combination such that there is no selectivity. Burndown applications in both corn and soybean often incorporate glyphosate, dicamba , and 2,4

- D and may include paraquat or glufosinate to control weeds prior to planting the crop.

Page 3

- 4• Pre

- emergence: applied after the crop is planted, but prior to emergence of weeds. Pre

emergent herbicides are generally not effective after weeds have establi shed

. They may be used p rior to or after crop emergence.

• Post

- emergence: applied after the weeds and crop emerges. Early post emergence application occurs when the crop has just emerged and the weeds are small. Post

emergent herbicides selectively target weeds relative to the crop. The post materials have activity when applied to leaves and can be used over the top of crops if the crop is resistant to the active ingredient.

Most herbicides used as pre

- plant and pre

- emergent applications are residuals, herbicides that remain active for several weeks and theoretically work continuously after application. These types of herbicides are finding increasing use in the management of glyphosate

- resistant weeds. (See Appendix 4, H erbicide U se T rends

, for more details). Examples include acetochlor, trifluralin, metolachlor, metolachlor

- S, pendimethalin, atrazine and alachlor. The se herbicides work by controlling weeds before they germinate or emerge. Usually residual herbicides need to be activated by water ( Hager and McGlamery 1997 )

. In rainfed crops, residual herbicides may fail to become activated during drought. When weather complicates the timing of herbicide applications with planting, g rowers may plant and apply the residual herbicide in a mix with a foliar applied product ( M onsanto 2010 )

. The foliar product controls emerged weeds while the residual material controls weeds prior to germination or emergence.

When herbicides are applied, biochemical pathways that control the growth and development of plants are interrupted a nd plant death and injury occurs ( Sosnoskie and Hanson , 2013) . These biochemical pathways control the growth and development of plants; when herbicides are applied, these processes are constrained and plant injury and death will occur. Mos t herbicides bind to, and thereby block the action of, a specific enzyme. Herbicides are classified according to their mode of action, which is the overall manner in which the herbicide affects a plant at the tissue or cellular level. The Weed Science So ciety of America (WSSA) has classified herbicides by group number, based on their mode of action. Brief descriptions of these groups are provided ( Sosnoskie and Hanson , 2013) :
Group 1: herbicides inhibit the action of acetyl CoA carboxyla se (ACCase) need ed for the synthesis of lipids. Grasses, but not broadleaf weeds, are affected.
Group 2: herbicides inhibit the action of acetolactate synthase (ALS) needed for the synthesis of three amino acids (isoleucine, leucine, and valine).
Group 3 : herbicides inhibit cell division (mitosis inhibitors).
Group 4: herbicides are growth regulators. At low concentrations, they mimic the plant growth hormone auxin and are referred to as synthetic auxins. At high concentration they produce distinctiv e symptoms on broadleaf weeds; twisted and curled stems, malformed flowers, thickened or stunted roots, and cupped, strapped or otherwise deformed leaves. Grasses are usually resistant.
Group 5, 6, and 7: herbicides inhibit photosynthesis leading to a bui ldup of highly reactive free radicals that damage chlorophyll and cell membranes.

Page 3

- 5Group 8 : herbicides inhibit fatty acid and lipid biosynthesis but not ACCase ( Group 1).
Group 9 : herbicides inhibit the action of the enzyme enolpyruvyl shikimate

- 3

- phos phate synthase (EPSPS) needed for the synthesis of three aromatic amino acids (tryptophan, phenylalanine, and tyrosine) that are produced through the shikimate pathway.
Group 10: herbicides inhibit glutamine synthetase. These herbicides stop the conversi on of glutamate and ammonia to glutamine which causes ammonia to accumulate in the plant, inhibiting photosynthesis and destroying plant cells.
Group 12: herbicides inhibit carotenoid biosynthesis. Lack of carotenoids results in destruction of chlorophyl l, which is needed for plant photosynthesis.
Group 14: herbicides inhibit protopophyrinogen oxidase (PPO). PPO inhibitors block the production of chlorophyll and cause reactive molecules to form in the cell, resulting in the destruction of existing chlorophyll molecules, carotenoids and cell membranes.
Group 15: herbicides block mitosis by inh ibiting the synthesis of very long chain fatty acids.
Group 20, 21, 29: herbicides inhibit the synthesis of cellulose needed for the synthesis of cell walls.
Group 22: herbicides inhibit photosystem I (PSI) forming reactive molecules that destroy lipids , eventually breaking down plant cell membranes.
Group 27: herbicides inhibit 4

- hydroxyphenyl

- pyruvate

- dioxygenase needed for the synthesis of carotenoids

. Herbicides with a common chemistry are grouped into “families.” Also, two or more families may have the same site of action, and thus can be grouped into “classes.” Table 3

- 2 provides WSSA herbicide groups with information on modes of action, chemical families, and example active ingredients and herbicides.

Table 3

- 2

. Herbicide G roups with E xample A ctive I ngredients and H erbicides. Site of Action Group (WSSA Group) Site of Action Number of Resistant

Weed Species in U.S. Chemical Family Active Ingredient Herbicide Lipid Synthesis Inhibitors 1 ACCase Inhibitors (acetyl CoA carboxylase) 15 Aryloxyphenoxy propionate (“FOPs”) fenoxaprop Puma diclofop Hoelon fluazifop Fusilade quizalofop Assure II Cyclohexanedione (“DIMs”) clethodim Select sethoxydim Poast Phenylpyrazoline (“DENs”) pinoxaden Axial XL

Page 3

- 6Site of Action Group (WSSA Group) Site of Action Number of Resistant

Weed Species in U.S. Chemical Family Active Ingredient Herbicide Amino Acid Synthesis Inhibitors 2 ALS Inhibitors (acetolactate synthase) 44 Sulfonylurea (“SUs”) chlorimuron Classic foramsulfuron Option halosulfuron Permit iodosulfuron Autumn nicosulfuron Accent primisulfuron Beacon prosulfuron Peak rimsulfuron Resolve thifensulfuron Harmony tribenuron Express metsulfuron Ally triasulfuron Amber chlorsulfuron Glean sulfofsulfuron Maverick mesosulfuron Osprey Imidazolinone (“IMIs”) imazamox Beyond imazaquin Scepter imazapic Cadre imazethapyr Pursuit Triazoloyrmidine flumetsulam Python

c h loransulam

methyl FirstRate

pyroxysulfam PowerFlex diclosulam Strongarm Triazolinones thiencarbazone Component of Caperno Pyrimidinyl(thio) benzoate pyrithiobac Staple

Sulfonylaminocar bonyl

triazilonones flucarbazone Everest

propoxycarbazone Olympus 9 EPSP Synthase Inhibitor 13 glyphosate RoundUp

Growth Regulators (Synthetic Auxins) 4

19 Specific Site Unknown 10 Phenoxy 2,4

- D 2,4

- DB Butyrac MCPA Benzoic acid dicamba Banvel Carboxylic acid chlo pyralid Stinger fluroxypr Starane picloram Tordon Auxin Transport 0 Semicarbazone diflufenzopyr Component of Status Photosynthesis Inhibitors 5 Photosynthesis II Inhibitors (binding sites other than 6 and 7) 24 Triazine prometryn Caparol atrazine Aatrex simazine Princep Triazinone hexazinone Velpar metribuzin Sencor
Page 3

- 7Site of Action Group (WSSA Group) Site of Action Number of Resistant

Weed Species in U.S. Chemical Family Active Ingredient Herbicide

6

7 Photosynthesis II Inhibitors (binding sites other than 5 and 7) 1 Nitrile bromoxynil Buctril

Benzodiazole bent a zon Basagran

Photosynthesis II Inhibitors (binding sites other than 5 and 6) 7 Ureas Lorox

Nitrogen Metabolism 10 Glutamine Synthesis Inhibitor Phosphonic Acid glufosinate Liberty

Pigment Inhibitors 13

27 Diterpene Synthesis Inhibitors 1 Isoxazolidinone clomazone Command

HPPD Inhibitors 1 Isoxazole isoxaflutole Balance Pyrazolone topramezone Impact Triketone mesotrione Callisto tembotrione Laudis

Cell Membrane Disruptors 14

27 PPO Inhibitors 2 Diphenylether acifluoron Blazer fomasefen Reflex lactofen Cobra oxyfluorfen Goal N

Phenylphthalamid

e flumiclorac Resource flumioxazin Valor

Aryl triazinone sulfentrazone Spartan carfentrazone Aim fluthiacet

- ethyl Cadet Photosystem I Electron Diverter 5 Bipyridium paraquat Gramoxone Inteon diquat Reglone Seedling Root Growth Inhibitors 3 Microtubule Inhibitors 6 Dinitroaniline ethalfluralin Sonalan pendamethalin Prowl

trifluralin Treflan Seedling Shoot Growth Inhibitors 8

15 Lipid Synthesis Inhibitors 8 Thiocarbamate butylate Sutan + EPTC Eradicane

Long

- chain Fatty Acid Inhibitors 1 Chloroacetamide acetochlor Harness alachlor Intrro metalochlor Dual
Page 3

- 8Site of Action Group (WSSA Group) Site of Action Number of Resistant

Weed Species in U.S. Chemical Family Active Ingredient Herbicide dimethanamid Outlook Oxyacetamide flufanacet Define Pyrazole pyroxasulfone Zidua Sources: ( Armstrong 2009
, Glyphosate Stewardship Working Group 2012 )

. Mechanical Weed Control

– Tillage

Prior to planting, the soil must be stripped of weeds that would otherwise compete with the crop for space, water, and nutrients. Tillage is used to prepare a seedbed, address soil compaction, incorporate fertilizers and herbicides, manage water movement both within and out of a
pr oduction field, and control weeds ( Heatherly, Dorrance et al. 2009 )

. Soil cultivation or tillage can be very valuable in many situations and should be considered as an alternate weed control practice where appropriate:

• Tillage serves as another way to control weeds and break certain weed patterns

• Tillage reduces complete reliance on herbicides

• Periodic tillage is a reliable cultural practice that also provides the benefits of removing trash build

- up on the soil surface and levels ruts or rough spots in fields.

Some form of c onservation tillage is utilized by t he majority of corn and soybean gro wers. Tillage can supplement chemical control (i.e., herbicides) and, in the case of light weed infestations, could provide sufficient control if used alone. Cultivation should be shallow to reduce crop root damage and to avoid breaking through any resid ual herbicide layer and bringing up untreated soil and weed seed. Use of tillage is optimized when weeds are small and should not be practiced for a week prior or after post

- emergence herbicide application ( York and Culpepper 2000 )

. Tillage can be a useful weed control method in some situations but may not be appropriate for all producers or areas

. For example, tillage is not a good practice where soils are susceptible to erosion. Also, no

- till soybean production is less successful in heavier, cooler soils more typical of northern latitudes ( Kok, Fjell et al. 1997

, NRC 2010 )

. Although tillage may control weeds, fuel costs and machine maintenance m ay represent substantial farm expenditures ( NRC 2010 ) . This fact and the availability of herbicide technology have driven producers to increasingly adopt chemical management strategies. For example, i n 2012, 98 percent of soybean acreage was treated with synthetic herbicides ( USDA

- NASS 2013 )

.
Cultural Weed Control The successive planting of different crops on the same land is known as crop rotation. In contrast, the planting of the same crop on the same field in successive years is known as continuous crop production. Crop rotations are used to optimize soil nutrition and fertility, reduce pathogen loads, control volunteers (carry over in successive years), and limit the potential for weeds to develop resistance to herbicides ( IPM 2 004
, IPM 2007
, USDA

- ERS 2010 )

. Page 3

- 9Crop rotation is also a key element of successful weed control as it often reduces the populations of weeds that closel y mimic the appearance of the young crop or are tolerant to herbicides often used in these crops. Crop rotation should be an integral component of a weed management program. Crop rotation generally leads to healthier crops that are more competitive with weeds. Moreover, certain weeds are more easily or more economically managed in one crop than in another. In general, most weeds are more easily managed in corn or soybeans than in other agronomic or horticultural crops. Good control in corn can reduce wee d problems in rotational
crops. Additionally, crop rotation allows use of different herbicide chemistries on the same field in different years. This can prevent weed population shifts (changes in the species composition), avoid selection of herbicide resi stan t weeds , and help to keep the overall weed population at lower levels.

Since 1991, 75% of corn planted acreage has been in some form of rotation ( USDA

- ERS 2010 )

. Corn can be grown successfully in a conserv ation tillage system if rotated with other crops such as wheat and soybeans, which will reduce some of the problems encountered with conservation tillage ( IPM 2007 ) . Crops used in rotation with corn vary regionally and include oats, peanut, soybean, wheat, rye, and forage ( USDA

- APHIS 2010 ) . Alternative rotations are an important aspect of overall management s trategies, and could theoretically reduce the cycle of herbicide applications associated with corn/soybean rotations ( DAS 2010 ) . However, the impact of these rotations does not appear to have be en studied in detail.

Consecutive plantings of corn frequently require at

- planting or pre

- plant pesticide treatments to control corn pests and pathogens as well as supplemental fertilizer treatments ( IPM 2004
, Erickson and Lowenberg

- DeBoer 2005

, Sawyer 2007
, Stockton 2007 ) . Corn

- to

- corn rotations also may require a change in tillage practices. Corn

- to

- corn cultivation may produce substantially greater quantities of field residue, requi ring additional tillage prior to planting ( Erickson and Lowenberg

- DeBoer 2005 ) . The increased adoption of corn

- to

- corn rotation, mainly in conventional and GE production systems, has been attributed to rising corn demand and prices ( Hart 2006
, Stockton 2007 )

. Crop rotation is a common practice on U .S. soybean fields, with approximately 95 percent of the soybean acreage planted in some form of a crop rotation system since 1991 ( USDA

- ERS 2011 )

. A variety of crops may be rotated with soybean. In terms of acreage however, corn is the most commonly rotated crop. In a survey of major corn/soybean production states, corn and soybean were alternated on 72 to 80 percent of acreage, other ro tations were grown on 16 to 20 percent of acreage, and soybean was grown continuously on 5 to 12 perce nt of acreage between 1996

- 2002 ( Sandretto and Payne 2006 ) . Other crops that may be rotated with soybean include wheat, cotton, rice, sorghum, barley, oats, and dry beans.

The mitigation of pest cycles on an agricultural field is one of the primary benefits of crop rotation. The rota tion of other crops following soybean production may disrupt pest life cycles that are more adapted to soybean fie ld cultivation than other crops ( Poole 2004 ) through the creation of a relatively unstable agroecosystem ( Weller, Owen et al. 2010 ) . For example, crop rotation may encourage the use of alternative he rbicides to further control broadleaf weeds in the same field in successive years that would not otherwise be used if cont inuous soybean was grown ( Gunsolus 2012 )

.

Page 3

- 10Planting high

- quality, weed

- free crop seed is another cultural practice that keeps weed infestations low and easier to manage. One of the most effective means of reducing weed competition is to establish a highly competitive crop. This is best accomplished by planting good quality seed into a well

- prepared seedbed with good fertility and soil moisture. Higher seeding rates can help establish a competitive crop and for some weed species delaying planting will allow for destruction of early flushes of weeds via tillage or non

- selective herbicide application.
Integrated Weed Management To reduce or mitigate against the selective pressures associated with the use of a s ingle weed management practice, agronomists have recommended that growers adopt a diverse weed management strat egy, also known as integrated weed management (IWM) ( Norsworthy 2012

, HRAC 2013 )

. Effective IWM in crops usually involves a combination of cultural, mechanical, and chemical methods. Thus, IWM does not exclude any one management technique. IWM integrates practices such as crop rotation, cover crops, competiti ve crop cultivars, the judicious use of tillage, and targeted herbicide application to reduce weed populations and selection pressures toward the development of herbicide resistant weeds ( Mortensen, Egan et al. 2012 )

. A variety of strategies have been proposed to help farmers deal with glyphosate

- resistant weeds ( Boerboom 1999

, Beckie 2006

, Sammons, Heering et al. 2007

, Frisvold, Hurley et al. 2009 )

. Resistance management begins with good agronomic practices, including the implementatio n of IWM to incorporate diverse weed control practic es to reduce the frequency of herbicide applications and decrease selection pressure for herbicide resistant weed populations ( Norsworthy 2012 )

. IWM programs that use herbicides from different groups, vary cropping systems, rotate crops, and use mechanical as well as chemical weed control methods will prevent the selection of herbicide

- resistant weed populations ( Powles 2008

, Green and Owen 2011

, Sellers, Ferrell et al. 2011

, Gunsolus 2012

, HRAC 2013 )

. The Herbicide Resistance Action Committee, an industry

- based group, has developed the following general principles of weed re sistance management:

• Apply integrated weed management practices. Use multiple herbicide sites

- of

- action with overlapping weed spectrums in rotation, sequences, or mixtures;

• Use the full recommended herbicide rate and proper application timing for the harde st to control weed species present in the field;

• Scout fields after herbicide application to ensure control has been achieved. Avoid allowing weeds to reproduce by seed or to proliferate vegetatively; and

• Monitor site and clean equipment between sites. For annual cropping situations, the following recommendations of the Herbicide Resistance Action Committee ( HRAC 2013 ) are provided:

• Start with a clean field and control weeds early by using a burndown treatment or tillage in combination with a pre

- emergence residual herbicide as appropriate;

• Use cultural practices such as cultivati on and crop rotation, where appropriate; and

• Use good agronomic principles that enhance crop competitiveness.

Page 3

- 11References
Armstrong, J. (2009). Herbicide How

- to: Understanding Herbicide Mode of Action, Oklahoma Cooperative Extension Service. PSS

- 2778

.

Beckie, H. J. (2006). "Herbicide

- resistant weeds: Management tactics and practices." Weed Technology 20 (3): 793

- 814.

Boerb oom, C. M. (1999). "Nonchemical options for delaying weed resistance to herbicides in Midwest cropping system." Weed Technology 13 : 636

- 642.

DAS (2010). Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

68416

- 4 Soybean. S. K. M ark, Dow AgroSciences.

Erickson, B. and J. Lowenberg

- DeBoer (2005). Weighing the Returns of Rotated vs. Continuous Corn. West Lafayette, IN, Top Farmer Crop Workshop Newsletter, Purdue University.

Farnham, D. (2001). Corn Planting. Ames, IA, Cooperativ e Extension Service, Iowa State University of Science and Technology : 8.

Frisvold, G. B., T. M. Hurley, et al. (2009). "Adoption of best management practices to control weed resistance by corn, cotton, and soybean growers." AgBioForum 12 : 370

- 381.

Gian essi, L. and N. Reigner (2007). "The value of herbicides in U.S. crop production." Weed Technology (21): 559

- 566.

Glyphosate Stewardship Working Group (2012). GWC

- 3, Corn and Soybean Herbicide Chart. Glyphosate, Weeds, and Crop Series

.

Green, D. J. and R. J. Martin (1996). "Dealing with Perennial Broadleaf Weeds in Conservation Tillage Systems."

Green, J. M. and M. D. Owen (2011). "Herbicide

- resistant crops: Utilities and limitations for herbicide

- resistant weed management." Journal of Agricultural and Food Chemistry 59 : 5819

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Gunsolus, J. (2012). "Weed Control in Soybean." from http://appliedweeds.cfans.umn.edu/weedbull/Soybeans.pdf

.

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- 12Hager, A. and M. McGlamery (1997). Prin ciples of Postemergence Herbicides. Champaign, IL, University of Illinois, Cooperative Extension Service : 3.

Hart, C. (2006) Feeding the Ethanol Boom: Where Will the Corn Come From? Iowa Ag Review 2011

,

Hartzler, B. (2008). "Timeliness Critical to Pr otect Corn Yields." Retrieved April 5, 2011, from http://www.extension.iastate.edu/CropNews/2008/0523BobHartzler.htm

.

Heatherly, L., A. Dorrance, et al. (2009). Sustainabi lity of U.S. Soybean Production: Conventional, Transgenic, and Organic Production Systems, Council for Agricultural Science and Technology.

HRAC (2013). "Herbicide Resistance Action Committee (HRAC): Resistance Management Strategies." from http://www.hracglobal.com/

.

IPM (2004). Crop Profile for Field Corn in Pennsylvania. University Park, PA, Department of Agronomy, Penn State University : 21.

IPM (2007). Crop Profile for Corn in the Northern and Central Plai ns (KS, NE, ND, and SD), : 26.

Knezevic, S. (2007) Timing Weed Control in Corn to Get the Most Effect. CropWatch

Knezevic, S. Z., S. P. Evans, et al. (2003). "Yield Penalty Due to Delayed Weed Control in Corn and Soybean." Crop Managment

.

Kok, H., D. Fjell, et al. (1997). Seedbed Preparation and Planting Practices

- Soybean Production Handbook. Manhattan, Kansas State University.

Linker, H., H. Coble, et al. (unknown) Chapter 3

- Scouting for Weeds. Scouting Soybeans in North Carolina

Monsanto (2010). Petition for the Determination of Nonregulated Status for Improved Fatty Acid Profile MON 87705 Soybean. G. Rogan. St. Louis, Monsanto Company.

Page 3

- 13Mortensen, D. A., J. F. Egan, et al. (2012). "Navigating a Critical Juncture for Sustainable Weed Mana gement." Bioscience 62 : 75

- 84.

NC State University (1998). "Postemergence, Non

- Selective Herbicides for Landscapes and Nurseries ". Retrieved 11/25/2013, from http://www.ces.ncsu.edu/dep ts/hort/hil/hil

- 648.html

.

Norsworthy, J. K., Ward, S. M., Shaw, D. R., Llewellyn, R. S., Nichols, R. L., Webster, T. M., Bradley, K. W., Frisvold, G., Powles, S. B., Burgos, N. R., Witt, W. W., and Barrett, M. (2012). "Reducing the Risks of Herbicide Res istance: Best Management Practices and Recommendations." Weed Science (Special issue): 31

- 62.

NRC (2010). The Impact of Genetically Engineered Crops on Farm Sustainability in the United States . Washington, DC, National Academies Press.

Ontario Ministry of Agriculture and Food (2009) Chapter 12: Weed Control: Crop Yield Losses Due to Weeds. Agronomy Guide for Field Crops

- Publication 811

Penn State Extention (2013). "Herbicides " Introduction to Weeds and Herbicides . 2013, from http://extension.psu.edu/pests/weeds/control/introduction

- to

- weeds

- and

herbicides/herbicides

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Poole, T. (2004). Crop Rotation, University of Maryland

- Maryland Coope rative Extension : 1

- 4.

Powles, S. B. (2008). "Evolution in action: Glyphosate

- resistant weeds threaten world crops." Outlooks on Pest Management 12 : 256

- 259.

Rosenberg, M. (2013) Effect Of Weed Competition On Corn iGrow

Sammons, R. D., D. C. Heering, et al. (2007). "Sustainability and Stewardship of Glyphosate and Glyphosate

- resistant Crops." Weed Technology 21 (2): 347

– 354.

Sandretto, C. and J. Payne (2006). Soil Management and Conservation, United States Department of Agriculture

- Economic Research Service.

Sawyer, J. (2007) Nitrogen Fertilization for Corn following Corn.

Sellers, B. A., J. A. Ferrell, et al. (2011) Herbicide Resistant Weeds. 2011

,

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- 14Sosnoskie, L. M. and B. Hanson (2013, March 1, 2013). "Understanding herbicide mechanisms (modes) of action and how they apply to resistance management in orchards and vineyards." Retrieved 11/25/2013, 2013, from http://ceventura.ucdavis.edu/?blogtag=mode%20of%20action&blogasset=19305#

.

Stockton, M. (2007). "Continuous Corn or a Corn/Soybean Rotation?". Retrieved April 19, 2011, from http://liferaydemo.unl.edu/web/cropwatch/archive?articleId=.ARCHIVES.2007.CROP4.C ROPCOMPARISON_WORKSHEET.HTM

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University of California (2009). UC IPM Pest Manageme nt Guidelines: Corn. Oakland, CA, University of California Agriculture and Natural Resources, UC Statewide Integrated Pest Management Program : 42.

USDA

- APHIS (2010). Plant Pest Risk Assessment for DAS

- 40278

- 9 Corn. Riverdale, MD, US Department of Agricu lture, Animal and Plant Health Inspection Service, Biotechnology Regulatory Services.

USDA

- ERS (2010, July 1, 2010). "Adoption of Genetically Engineered Crops in the U.S.: Corn Varieties." Retrieved April 4, 2011, from http://www.ers.usda.gov/Data/BiotechCrops/ExtentofAdoptionTable1.htm

.

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- ERS (2010). "Conservation Policy: Compliance Provisions for Soil and Wetland Conservation." Retrieved December 3, 2010, from http://www.ers.usda.gov/Briefing/ConservationPolicy/compliance.htm

.

USDA

- ERS (2011). Major Uses of Land in the United States, 2007. Economic Information Bulletin . C. Nickerson, R. Ebel, A. Borchers and F. Carriazo. USDA

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- NASS (2013). Field Crop Totals.

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- based Utility." from http://weedsoft. unl.edu/weedsoftapps.htm

.

Weller, S., M. Owen, et al. (2010). Managing Glyphosate

- resistant Weeds and Populations Shifts in Midwestern U.S. Cropping Systems. Glyphosate Resistance in Crops and Weeds . Hoboken, NJ, John Wiley & Sons, Inc. : 213

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- 15York, A. C. and A. S. Culpepper (2000). "Weed Management." from http://www.ces.ncsu.edu/plymouth/cropsci/cornguide/Chapter8.html

.

Page 3

- 16

### Herbicide Use Trends a nd Predicted Use on EnlistTM Corn Appendix 4.

a nd Soybean

Page 4

- 1Herbicide Use Trends and Predicted Use on Enlist TM Corn and Soybean

I n recent years , h erbicide use data has generally not been publicly available . For this analysis, third party proprietary data was obtained by DAS and assumed to be “reported correctly”. APHIS used this information to identify the major herbicides, herbicide sites of action, and trends in their use on soybean and corn for the past twenty years. National usage is r eported using the metric treatment acres and not pounds of active ingredient used per crop. P ounds of active ingredient per crop over emphasizes herbicides that are used at high application rates (such as glyphosate, 2,4

- D, and chloroacetamides) and under estimates the use of herbicides used at low application rates (such as

a cetolactate synthase (ALS) and a cetyl

- CoA carboxylase (ACCase) inhibitors). The latter herbicides may be used at rates 100 times less than the former. Treatment acres refer to the acr es of land treated with a particular herbicide summed for each time the land is sprayed. For example, if one acre of land is sprayed twice with a particular herbicide, it is counted as two treatment acres for that herbicide. This metric gives a better repr esentation of grower reliance for a particular herbicide than does pounds of active ingredient.

Corn Herbicide Use Trends

The ten most actively used herbicides used on corn

, based on trea tment acres and in order of use, nationwide and regionally in 2011 ar e shown in Table 4

- 1 and Table 4

- 2 , respectively. The top 10 herbicides accounts for greater than 95% of the herbicide use on corn ( Rausch, 2013 )

. Atrazine has historically been the most widely used herbicide on corn through as late as 2007 and is still widely used. In 2007, glyphosate became the most widely used herbicide on corn and its use has continued to increase through 2011. In addition, chlo roacetamide herbicides are also still widely used including acetochlor and metolachlor

- S. These two chloroacetamides have largely replaced alachlor and metolachlor, which were the predominant chloroacetamides used prior to 1997. Synthetic auxins such as 2 ,4

- D and dicamba were also commonly used p rior to the adoption of RR

corn. As glyphosate use increased, synthetic auxin use decreased but both dicamba and 2,4

- D are now finding increased use in corn as is a third synthetic auxin, clopyralid. Presumably t he increased use of synthetic auxins is in response to the increasing prevalence of glyphosate tolerant and resistant weeds. In addition, the two HPPD type inhibitors, mesotrione and isoxaflutole, are finding increased use, as is the ALS inhibitor, flumets ulam.

Also shown in Table 4

- 1 are the WSSA group number, chemical family name, and site of action for the ten herbicides. These ten widely used corn herbicides represent six herbicide sites of action (Group 9: EPSPS inhibitors, Group 5: Photosystem II inh ibitors, Group 15: very long chain fatty acid inhibitors, Group 27: 4

- HPPD inhibitors, and Group 4: synthetic auxins). For the regional data in Table 4

- 2, just the active ingredient and group number are shown.

Table 4

- 1

. Top 10 Nationally Used Herbicides on Corn

Active Ingredient WSSA Group Chemical Family Site of Action

glyphosate 9 Glycine 5

- enolpyruvylshikimate

- 3

- phosphate synthase atrazine 5 Triazine Photosystem II acetochlor 15 Chloroacetamide Very Long Chain Fatty Acids Page 4

- 2Active Ingredient WSSA Group Chemical Family Site of Action

metolachlor

- S 15 Chloroacetamide Very Long Chain Fatty Acids

mesotrione 27 Callistemones 4

- Hydroxyphenyl

- pyruvate dioxygenase dicamba 4 Benzoic Acid Synthetic Auxin

2,4

- D 4 Phenoxy

- carboxylic acid Synthetic Auxin
clopyralid 4 Pyridine carboxylic acid Synthetic Auxin flumetsulam 2 Triazolopyrimidine Acetolactate synthase

isoxaflutole 27 Isoxazole 4

- Hydroxyphenyl

- pyruvate dioxygenase Source: ( DAS, 2013a )

Table 4

- 2

. Top 10 Regionally Used Herbicides on Corn Heartland (6) N Crescent (6) N Great Plains (6) Prairie Gateway (7) Southeast (7)
AI GN AI GN AI GN AI GN AI GN glyphosate 9 glyphosate 9 glyphosate 9 glyphosate 9 glyphosate 9 atrazine 5 atrazine 5 atrazine 5 atrazine 5 atrazine 5 acetochlor 15 metolachlor

- S 15 acetochlor 15 dicamba 4 metolachlor

- S 15 mesotrione 27 mesotrione 27 metolachlor

- S 15 2,4

- D 4 mesotrione 27 metolachlor

- S 15 acetochlor 15 mesotrione 27 metaolachlor

- S 15 2,4

- D 4 flumetsulam 2 flumetsulam 2 isoxaflutole 27 acetochlor 15 dicamba 4 clopyralid 4 clopyralid 4 dicamba 4 mesotrione 27 rimsulfuron 2 isoxaflutole 27 dicamba 4 2,4

- D 4 isoxaflutole 27 simazine 5 2,4

- D 4 2,4

- D 4 clopyralid 4 difluflenzopyr 19 paraquat 22 thiencarbazone

methyl 2 rimsulfuron 2 flumetsulam 2 carfentrazone

ethyl 14 nicosulfuron 2 Source: ( DAS, 2013a ) Heartland: MN, IA, MO, IL, IN, KY, OH Northern Crescent: WI, MI, PA, NJ, NY, MA, RI, CT, VT, NH, ME Northern Great Plains: MT, ND, SD, NE Prairie Gateway: CO, KS, OK, TX Southeast: AS, LA, MS, AL, GA, SC, NC, TN, VA, WV, MD, DE Numbers next to the regions represent number of sites of action in the top ten most frequently used herbicides

. AI: active ingredient GN: WSSA group number
Regional herbicide use on corn largely mirrors national use. The ten most widely used herbicides represent either 6 or 7 sites of action. In all regions glyphosate and atrazine are the two most frequently used herbicides. After atrazine, chloroacetamides and then HPPD inhibitors are in most frequent use in all regions e xcept the Prairie Gateway. In this region, synthetic auxins, dicamba and 2,4

- D are the most frequently used herbicides after atrazine. There are some differences in the type of ALS inhibitor used between regions. The Prairie Gateway and Northern Great Plai ns seldom rely on ALS inhibitors in corn. In the other areas, flumetsulam or rimsulfuron are the most

Page 4

- 3commonly used ALS inhibitors. Both the Prairie Gateway and the Southeast use 7 modes of action compared to six in the other regions. In the Prairie Gatewa y, the seventh site of action is the PPO inhibitor, carfentrazone

- ethyl, and in the South the 7 th site of action is, paraquat, a PSI inhibitor which is commonly included in burndown applications

.
Trends in H erbicide U se on Corn by Site of Action (SOA)

Al though weed resistance may be selected against one herbicide in a group and not another (for example lambsquarters biotypes have been selected against the synthetic auxin dicamba but not 2,4

- D ( Heap, 2011 ) ), there are examples where selection against one herbicide in the Group also

cross selects resistance to other herbicides of that Group. For example, a biotype selected against the Group 2 herbicide imazethapyr was cross resistant to several other Group 2 herbicides including imazapic, chlorimuron, pyrithiobac, and flumetsulam ( Heap, 2011 ) . From the standpoint of man aging weed resistance, it is better to rotate herbicide sites of action rather than herbicides within a site of action. Because selection of herbicide resistant weeds is a prominent issue in this EIS, the analysis of herbicide use focuses on sites of actio n rather than individual herbicides. Figure 4

- 1 shows the trends in use of herbicide sites of action on corn nationally and by region in five year increments since 1990 and in 2011. Group 9 (g lyphosate ) use on corn has been increasing in all regions of th e country while there appear to be decreases in the use of Group 15 ( chloroacetamides )
, Group 2 ( ALS inhibitors ) , and Group 5 (largely atrazine ) herbicides . There have been increases in Group 4 ( auxin ) herbicide use regionally in the Southeast and Prairie Gateway.

Page 4

- 4Source: ( DAS, 2013d )

. Classification of herbicid es according to site of action.: http://www.hracglobal.com/Publications/ClassificationofHerbicideSiteofAction.aspx Classification of Mechanism of Action http://wssa.net/weed/resistance/

. Figure 4

- 1

. Trends in Herbicide use on corn by S OA.

SOA 1 2 3 4 5 6 7 8 9 Chemical Family ACCase ALS Mitosis Inhib Auxins PS II Inhib-A1 PS II Inhib-B PS II Inhib-A2 FALB Inhib EPSP Inhib

SOA 10 13 14 15 16 19 22 27 Other Chemical Family GS Inhib DOXP Inhib PPO Inhib VLCFA Inhib Unknown ATI PS I Inhib HPPD Inhib U S

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

2 3 4 5 6 8 9 15 16 27 OTHER Heartland

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

2 4 5 6 8 9 15 16 Other 27

Northern Crescent

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

2 4 5 8 9 15 Other 3 22 27 Northern Plains

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

2 4 5 6 8 9 15 16 Other 3 19 27

Prairie Gateway Southeast 

## Corn

Page 4

- 5Soybean Herbicide Use Trends

The trend in soybean herbicide use changed dramatically with the introduction of Roundup Ready TM (RR) soybeans in 1996. The adoption of RR soybeans allowed post emergent application of a systemic herbicide (glyphosate) that controlled most grasses and broadleaves with one product that only required an average of 1.5 applications during the course of a season. This had the added benefits of using a single rate across soil types or pH and did not require either mechanical incorporation into the soil or rainfall for activation. This proved an attractive option for farmers that allowed a simpler solution and also gave a better weed control result in many cases and at less cost. The use of glyphosate post emergent on RR soybeans worked very well because soybeans are usually planted in narrow rows which provide rapid canopy closure thereby preventing most w eeds from germinating. The benefit of total post emergent weed control also supported adoption of no till practices, saving time and money for the grower while reducing soil erosion.

In 1995 prior to the int roduction of glyphosate

- resistant soybean , the m ost commonly u sed herbicides in soybean were: imazethapyr (44 percent of soybean acres treated), pendimethalin (26 percent), trifluralin (20 percent), glyphosate (20 percent) (for pre

- plant weed control)and metolachlor (10%) ( USDA

- NASS, 1995 ) . By 2001, glyp hosate had become the most commonly used herbicide in soybean, used on 73 percent of soybean acres, followed by pendimethalin (10 percent), imazethapyr (9 percent), fomesafen (7 percent), and trifluralin (7 percent) ( USDA

- NASS, 2002 ) . Metolachlor no longer was included in the he top 10 most commonly used herbicides on soybean.

In 2006, glyphosate (all forms) continued to be the most commonly used herbicide on soybean; it was used on more than 96 percent of soybean acres and that use has largely continued t o the present (Table 4

- 3 ). The next most commonly used herbicide on soybean was 2,4

- D (all forms). Its use on soybean for pre

- plant weed control has been steadily increasing since 2008 and in 2011 it was used on more than 12 percent of soybean acres.

Ta ble 4

- 3

. Estimated 2,4

- D, Glyphosate, and Glufosinate Use in Soybean, 2008

- 2011

Year Total Soybean

Acres 2,4

- D Glyphosate Glufosinate
( percent

acres treated) ( lbs/acre) ( percent

acres treated) ( lbs/acre) ( percent

acres treated) ( lbs/acre)

2008 74,404,953 7 0.54 96 1.32
2009 77,584,979 10 0.48 94 1.30 0.3 0.46

2010 78,725,007 10 0.53 94 1.38 1.1 0.52

2011 74,835,007 12 0.55 96 1.40 1.3 0.53

2012 75,939,995 NA NA NA NA 3.9 0.51
NA

– Not Available Source : ( DAS, 2012c )

Page 4

- 6Although glyphosate use on soybean has remained fairly constant, since 2006, there has been a trend to use non glyphosate herbicides for both pre

- and post

- emergent applications

, as depicted in Fig ure 4

- 3 . As noted in Table 4

- 3, glufosinate use has also been increasing as more growers use soybean with the LibertyLink ® trait. Between 2011 and 2012, glufosinate use increased 3 fold from 1.3% to 3.9% of acres treated.

Source: Total acre treatments from ( Monsanto, 2012 ) ; soybean planted acres from ( USDA

- NASS, 2002 ; USDA

NASS, 2004 ; USDA

- NASS, 2006 ; USDA

- NASS, 2007 ; USDA

- NASS, 2009 ; USDA

- NASS, 2011 ) Figure 4

- 2

. Total Acre Treatments p er Soybean Planted Acre and Adoption of GE Herbicide Resistant Soybeans, 2002

- 2011

Table 4

- 4 lists the 10 most frequently used herbicides on soybean in 2011 based on treatment acres in the order of their use. The top 10 herbicides account for greater than 95% of the herbicide use on soybean ( Rausch, 2013 )

. Glyphosate remains the most widely used herbicide though its dominance has been steadily declining since 2005. After glyphosate, the nine most frequently u sed herbicides comprise another five sites of action. These include in order of use, Group 14 PPO inhibitors (flumioxazin and fomesafen), Group 2 ALS inhibitors (chlorimuron, imazethapyr, thifensulfuron), Group 4 synthetic auxins ( 2,4

- D ), Group 15 chloroa cetamides (metolachlor

- S and acetochlor), and Group 1ACCase inhibitor (clethodim) herbicides

.
Table 4

- 4

. Top 10 M ost F requently U sed H erbicides on S oybean in 2011 ( N ationally )

Active Ingredient WSSA Class Chemical Family Site of Action
glyphosate 9 glycine EPSP synthase chlorimuron 2 sulfonylurea Acetolactate synthase 0 10 20 30 40 50 60 70 80 90 100

0 0.5

1 1.5

2 2.52002200320042005200620072008200920102011US Adoption Rate for GE Herbicide Tolerant SoybeansTotal Acre Treatments Per Soybean Planted Acre

PRE non-glyphosate

PRE glyphosate

POST non-glyphosate

POST glyphosate

TOTAL

GE herbicide tolerant soybean adoption

Page 4

- 7Active Ingredient WSSA Class Chemical Family Site of Action

flumioxazin 14 N

- phenylpthalimide Protoporphyrinogen oxidase

2,4

- D 4 Phenoxy

- carboxylic acid Synthetic a uxin

F omesafen 14 Diphenylether Protoporphyrinogen oxidase
I mazethyapyr 2 Imidazolinone Acetolactate synthase

M etolachlor

- S 15 Chloroacetamide Very l ong chain fatty acids C lethodim 1 C yclohexandione AcetylcoA carboxylase C hloransulam

methyl 2 Triazolopyrimidine Acetolactate synthase

Thifensulfuron

methyl 2 S ulfonylurea Acetolactate synthase

Source : ( DAS, 2013a )

Regional Use of Herbicides in Soybean by U

. S

. Cropping Region

Most of U.S. soybean production occurs in the five regions indicated in Table 4

- 2 . Herbicide use on soybeans was examined in these five regions and the top 10 herbicides used are listed in Table 4

- 5 based on treatment acres in the order of their use . The Heartland region is where most soybeans are grown in the U

. S

. and accounts for half of all soybean herbicide treatments (data not shown). Overall, the herbicides used to control weeds in soybean are similar across regions. Glyphosate provides the principal basis for weed control in each of the regions with other actives from Group 2, Group 4, and Group 14 being used to control weeds that are not controlled satisfactorily by glyphosate alone

. Some regional differences in herbicide use are as follows:

• In the Heartland, Northern Crescent, and Northern Great Plains, Group 15 herbicides are not widely used while the Group 1 grass herbicides are.

• The Northern Crescent is the one region where Group 5 Photosystem II inhibitors are widely used. The Northern Crescen t is less reliant on synthetic auxins and uses a smaller variety of PPO inhibitors and a greater variety of ALS inhibitors.

• In the Northern Great Plains and the Prairie Gateway, Group 3 (mitosis inhibitors) herbicides are widely used.

• In the Southeast, Gro up 22 (Photosystem I) and Group 10 (Glufosinate) are widely used.

• Overall, the Heartland, uses the fewest sites of action in the top ten herbicides (5), the Southeast the most (7), while the other three regions use (6).

Page 4

- 8Table 4

- 5

. Top T en H erbicides and WSSA Group U sed on S oybean in the 5 P rincipal G rowing R egion s Heartland (5) N Crescent (6) N Great Plains (6) Prairie Gateway (6) Southeast (7) AI GN AI GN AI GN AI GN AI GN glyphosate 9 glyphosate 9 glyphosate 9 glyphosate 9 glyphosate 9 chlorimuron 2 chlorimuron 2 imazethyapyr 2 chlorimuron 2 fomesafen 14 flumioxazin 14 imazethyapyr 2 saflufenacil 14 flumioxazin 14 flumioxazin 14 2,4

- D 4 flumioxazin 14 2,4

- D 4 2,4

- D 4 chlorimuron 2 clethodim 1 clethodim 1 clethodim 1 metolachlor

- S 15 metolachlor

- S 15 sulfentrazone 14 2,4

- D 4 flumioxazin 14 fomesafen 14 2,4

- D 4 chloransulam

methyl 2 metribuzin 5 chlorimuron 2 sulfentrazone 14 paraquat 22 imazethyapyr 2 thifensulfuron 2 pendimethalin 3 thifensulfuron 2 thifensulfuron 2

fomesafen 14 tribenuron methyl 2 chloransulam

methyl 2 lactofen 14 glufosinate 10

thifensulfuron 2 chloransulam

methyl 2 Fluthiacet

methyl 14 pendimethalin 3 dicamba 4 Heartland: MN, IA, MO, IL, IN, KY, OH Northern Crescent: WI, MI, PA, NJ, NY, MA, RI, CT, VT, NH, ME Northern Great Plains: MT, ND, SD, NE Prairie Gateway: CO, KS, OK, TX Southeast: AS, LA, MS, AL, GA, SC, NC, TN, VA, WV, MD, DE Numbers next to the regions represent number of sites of action in the top ten most frequently used herbicides

. AI: active ingredient GN: WSSA group number Source: ( DAS, 2013a )

Trends in H erbicide U se o n Soybean by Site of Action (SOA)

Fig ure 4

- 3 shows trends in herbicides used on soybean from 1990

- 2010 in five year intervals and for 2011 alone, grouped according to Weed Science Society of America (WSSA) chemical classification for sites of action ( WSSA, 2013 ) . The analysis presents each herbicide site of action (SOA) as a percentage of th e total treatment area of all actives used in that year. This approach allows a consistent comparison of herbicides used given the changes in crop area over time. The figure also breaks down usage by region. It illustrates the decreasing reliance of soybea n growers on glyphosate and the utilization of additional sites of action including PPO inhibitors (Group 14), ALS inhibitors (Group 2), chloroacetamides (Group 15), and synthetic auxins (Group 4) (Fig ure 4

- 3).

In all regions there has been a similar incre asing trend in the use of non

- glyphosate herbicides as weed control has slipped in recent years with some weeds developing increased tolerance or resistance to glyphosate and Group 2 herbicides. In all the major soybean growing regions, the next most widel y used herbicide is either a group 2 (chlorimuron and/or imazethapyr) or a Group 14 (flumioxazin, fomesan, or saflufenacil) herbicide. In all the regions 2,4

- D is also widely used. There is increasing pre

- emergent applications of residual herbicides such a s metolachlor

- S and pendimethalin in the Northern Great Plains, the Prairie Gateway, and the Southeast. These

Page 4

- 9herbicides prevent weeds from germinating over a period of 4

- 6 weeks and help control glyphosate resistant weeds provided there is adequate rain f or activation.

In the Southeast, where glyphosate resistant weeds are the most prevalent, there is a decreasing trend in glyphosate use and the greatest use of different sites of action among the various regions.

Page 4

- 10Figure 4

- 3 . Trends in H erbicide U se on S oybean by SOA 

### Soybean

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

1 2 3 4 5 6 9 13 14 15 Other Heartland

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

1 2 3 4 5 6 9 13 14 15 Other Northern Plains

SOA 1 2 3 4 5 6 7 8 9 Chemical Family ACCase ALS Mitosis Inhib Auxins PS II Inhib-A1 PS II Inhib-B PS II Inhib-A2 FALB Inhib EPSP Inhib

SOA 10 13 14 15 16 19 22 27 Other Chemical Family GS Inhib DOXP Inhib PPO Inhib VLCFA Inhib Unknown ATI PS I Inhib HPPD Inhib
Source: ( DAS, 2013d ) Classification of herbicides according to site of action. http://www.hracglobal.com/Publi cations/ClassificationofHerbicideSiteofAction.aspx Classification of Mechanism of Action http://wssa.net/weed/resistance/ 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

1 2 3 4 5 6 9 10 14 15 22 Other Southeast

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

1 2 3 4 5 6 9 13 14 15 Other Prairie Gateway

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

1 2 3 4 5 6 7 9 13 14 15 Other Northern Crescent 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

1990 1995 2000 2005 2010 2011

1 2 3 4 5 6 9 14 15 Other US

Page 4

- 11Summary of Herbicide T rends in S oybean

Trends in herbicide use are evident in Fig ure 4

- 3 . Since the mid

- 2000s
, at the national level, the use of glyphosate and microtubule inhibitor s has been declining. The use of four other sites of action has been increasing. These are the ALS inhibitor, chlorimuron, the PPO inhibitors flumioxazin and fomesafen, the auxin 2,4

- D and the chloroacetamide, metolachlor

- S. The greatest decline in glyp hosate use has been in the southeast. In all 5 soybean regions, chlorimuron use on soybeans appears to be increasing. In the Prairie Gateway and Southeast, 2,4

- D and flumioxazin use on soybean appears to be increasing. In the Southeast, fomesafen and metolachlor

- S use also appear to be increasing.

Comparison of Herbicide Use in Corn and Soybean

Herbicide use in corn differs substantially from that in soybean both in the types of herbicides used and the variety of herbicide sites of action. Corn yields are more negatively impacted by early season weed competition than soybeans. Corn is also planted in wider rows than soybeans and the resulting penetration of light allows weed germination over a longer period of time than in soybeans ( Rausch, 2013 ) . For these reasons, post emergent applications of glyphosate are not as beneficial i n corn as they are in soybean. To obtain the best corn yields, growers need to manage weeds with pre

- plant or pre

- emergent herbicide applications. Historically they have used atrazine, and chloroacetamide herbicides such as acetochlor, metolachlor, and mor e recently metolachlor

- S. They also relied on both dicamba and 2,4

- D . Even after RR corn was widely adopted, most corn growers have continued to use residual herbicides followed by application of post emergent herbicides as needed to provide good weed cont rol and maximize yield potential. Consequently, soybean growers have been much more reliant on glyphosate than have corn growers.

Figure 4

- 4 shows the number of herbicidal sites of action (SOA) corn and soybean growers used in 2005, 2008, and 2011. Wherea s 3/4 of soybean growers relied exclusively on a single SOA for their weed control in 2005, less than 1⁄4 of corn growers similarly relied o n a single SOA . When only one SOA is used, in both cases the predominant herbicide is glyphosate (Figure 4

- 5 ). For soy bean growers who used just one SOA , greater than 97% of the growers used exclusively glyphosate whereas in corn, this number was 75% in 2005 but increased to 90% in 2011. The alternative herbicides that are used as the only SOA on corn include atrazine, gl ufosinate, HPPD inhibitors, or chloroacetamides. However more commonly, several SOAs are used to raise corn. Over 30% of corn growers used at least three sites of action and this trend did not change over the period of 2005 to 2011 (Fig ure 4

- 4 ). In compar ison, over the same period of time soybean growers using three sites of action changed from just over 5% to nearly 20%. S oybean growers using only glyphosate decreased to just over 65% in 2008 and further decreased to 44% of growers in 2011

. As in soy bean , the recent trend in corn has also been to use even more herbicide SOAs . For example from 2005 to 2011, the percentage of growers using 4 SOAs almost doubled from 10% to 20%. There has also been an upward trend in corn growers using herbicides representin g 5 and 6 SOAs

.

Page 4

- 12Source: ( DAS, 2013c ) Figure 4

- 4

. Herbicide sites of action used in soybeans and corn since 2005 based on national data.

Number of Sites of Action Used/Acre Number of Sites of Action Used/Acre Trends in SOA in Soybeans

Trends in SOA in Corn Number of Sites of Action Used/Acre

Number of Sites of Action Used/Acre

Page 4

- 13Figure 4

- 5 . Herbicides used in Corn and Soybean when a Single Herbicide is Applied. Source: ( DAS, 2013d ) Proportion of Soybean Area Recieving One Active in 2011 by Site of Action

9 Glyphosate

2 ALS

Other Proportion of the Corn Area Recieving One Active in 2011 by Site of Action

9 Glyphosate

5 triazines

10 glufosinate

27 isoxaflutole, mesotrione

Other

Proportion of Soybeans Recieving 1 SOA in 2008 by SOA

9 Glyphosate

other Proportion of Corn Area Recieving 1 SOA in 2008 by SOA

9 Glyphosate

27 isoxaflutole, mesotrione

5 triazines

15 acetamides

other

Proportion of Soybeans Recieving 1 SOA in 2005 by SOA

9 Glyphosate

other Proportion of Corn Recieving 1 SOA in 2005 by SOA

9 Glyphosate

5 triazines

15 acetamides

27 isoxaflutole, mesotrione 10 glufosinate Soybean receiving 1 SOA Corn receiving 1 SOA

2011 2011

20 08 20 08

20 05 20 05

Page 4

- 14Trends in P replant/ P re

- emergent vs P ost

- emergent H erbicide U se in C orn and S oy
As described more fully in Appendix 3, pre

- plant herbicide use refers to use of the herbicide prior to planting the crop, pre

- emergent describes use of the herbicide prior to weed emergence, and postemergent describes use after the crop and weeds emerge. F igure 4

- 6 shows the most commonly used herbicides on corn and soybean and the percent each herbicide was used pre

- plant / pre

emergent (pre) or post

- emergent (post) in approximately five year increments since 1990 ( DAS, 2013a )

. In some situations, such as the use of herbicide on perennial crops and fallow, this nomenclature is not applicable (NA) and notated accordingly. Herbicides that are primaril y used in
pre

- emergent applications include acetachlor, metolachlor, metolachlor

- S, atrazine, isoxaflutole, pendimethalin trifuralin, and paraquat. Herbicides that are used primarily post emergent include fomesafen, imazethapyr

, thifensulfuron, glyphosate, and glufosinate. Some herbicides are widely used for both pre plant/pre

- emergent and post

- emergent applications including 2,4

- D , dicamba, flumetsulam, and mesotrione . One noteworthy trend is that for both 2,4

- D and dicamba, pre

- plant uses are increasing w hile post

- emergent uses are declining. Presumably this use reflects increased use of these herbicides for pre

- plant burndown to better manage glyphosate resistant weeds.

Page 4

- 150% 20% 40% 60% 80% 100%NAPOSTPRENAPOSTPRENAPOSTPRENAPOSTPRENAPOSTPRE

Flumetsulam Fomesafen Glufosinate Glyphosate Imazethapyr

0% 20% 40% 60% 80% 100%

NA POST PRE NA POST PRE NA POST PRE NA POST PRE

Isoxaflutole Mesotrione Metolachlor Metolachlor-S 0% 20% 40% 60% 80% 100%

NA POST PRE NA POST PRE NA POST PRE NA POST PRE

Pendimethalin Thifensulfuron Trifluralin Paraquat 0% 20% 40% 60% 80% 100%

NA POST PRE NA POST PRE NA POST PRE NA POST PRE

2,4

- D Acetachlor Atrazine Dicamba 1990

1995

2000

2005

2011

Figure 4

- 6

. Timing of H erbicide U se

. For each herbicide, the percentage of that herbicide used either post emergent, pre

- emergent, or in situations where the timing is not applicable (NA) is noted for the years indicated. Source: ( DAS, 2013a )
Page 4

- 16Common and U nique H erbicides U sed in C orn and S oy bean

One of the strategies to reduce the pressure of selecting herbicide resistant weeds is to diversify the herbicide sites of action that are used. As crops often are managed with different herbicides, crop rotation can facilitate the use of different herbicidal sites of action. To compare the extent to which herbicide sites of action would vary in a corn

- soy rotation, the common and unique herbicides were identified from among the most widely used herbicides in the two crops. Sites of action corresponding to these herbicides were then compared. This information is presented in Table 4

- 6 for each of the five major corn and soybean regions. If an herbicide is used only on soybean in a particular region, the corresponding matrix square is colored blue. If the herbicide is only used on corn, the square is colored yellow. If the herbicide is used on both crops, the square is colored green. The stippled green squares represent the situation where a common SOA is used on both crops but the herbicides used differ. For the most part, Group 14 PPO inhibitors, Group 1 ACCase inhbitors, and Group 10 glufosinate herbicides are used o n soy. Group 5 PSII inhibitors and Group 27 HPPD inhibitors are used on corn. The Group 15 chloroacetamides, which historically have been used primarily on corn, are now seeing increased use on soybean especially in the Prairie Gateway and the Southeast. G lyphosate and auxins, particularly 2,4

- D are used on both corn and soybean. The auxins, dicamba and clopyralid, are still mostly used on

corn.

Table 4

- 6

. Common and U nique H erbicides U sed in C orn and S oy 1

Re gions Heartland Northern Crescent N orthern Great Plains Prairie Gateway Southeast Sites of Action WSSA EPSPS 9 both both both both both Auxin Action 4 both both both both both PSI 22 N/A N/A N/A N/A both ALS 2 soy PPO 14 soy soy soy soy ACCase 1 soy soy soy N/A N/A Microtubule 3 N/A N/A soy soy N/A GS 10 N/A N/A N/A N/A soy PSII 5 corn corn corn corn HPPD 27 corn corn corn corn corn Chloroacetamide 15 corn corn corn both both

1 based on the 10 most widely used herbicides in a given region: Source: ( DAS, 2013a )

. Key Green (both ): Herbicides with the same site of action used in both soybean and corn in a given region. Green Shaded : Herbicides with the same site of action used in both soybean and corn but differing in individual herbicides. Blue ( soy ): Herbicides with a site of action used only on soy in a given region. Yellow (corn) : Herbicides with a site of action used only on corn in a given region. White (N / A): Not applicable because herbicides with that site of action are not used in the region.

Page 4

- 17Herbicide Use in the Different Market Segments

O nly a few o f the ma jor herbicides used in corn and soybean have a major portion of their use in

non

- crop markets. These herbicides are glyphosate, pendimethalin and the synthetic auxins 2,4

- D, clopyralid, and dicamba (Fig ure 4

- 7). In addition to use on agricultural crops, these herbicides are applied for use on range and pasture use and non

- crop uses.

Figure 4

- 7 . Herbicide U se by M arket S egmen t Source: ( DAS, 2013a )

. Current 2,4

- D U se
The herbicide 2,4

- D is a phenoxy auxin herbicide, introduced more than 60 years ago and registered and used throughout the world for the treatment of broadleaf weeds. The mode of action of 2,4

- D is described as an “auxin mimic,” meaning that it kills the target weed by mimicking auxin plant g rowth hormones like indole acetic acid (IAA ) ( Tu et al. , 2001 ) . A uxins and synthetic auxinic herbicides regulate virtually every aspect of plant growth and development; at low doses, auxinic herbicides possess similar hormonal properties to natural auxin ( Kelley and Clopyralid Use by Segment

Crop Use
Range & Pasture
Non Ag 

### Pendimethalin Use by Segment 2011

Crop Use

Range & Pasture
Non Ag



### Dicamba Use by Segment 2011

Crop Use

Range & Pasture
Non Ag Glyphosate Use by Segment 2011

Crop Use
Range & Pasture
Non Ag

2011 Use of 2,4

- D by Pounds Active

Crops
Range & Pasture

Non

- Crop glyphosate c lopyralid

dicamba pendimethalin

2,4

- D

Page 4

- 18Riechers, 2007 ) . However, as rates increase, they can cause various growth abnormalities in sensitive dicots ( Tu et al. , 2001 ) . Ob servable plant responses to 2,4

- D can include epinasty, root growth inhibition, meristematic proliferation/callusing, leaf cupping/narrowing, stem cracking, adventitious root formation, senescence, and chlorosis. This uncontrolled and disorganized plant g rowth eventually leads to plant death when applied at effective doses ( Tu et al. , 2001 ) . The agricultural segment is made up of the crop use segment and the range and pasture segment. With in the crop segment these uses are very diverse ranging from burndown application prior to planting soybeans, to use underneath tree crops and use on wheat. The range and pasture segment consists of control of annual weeds as well as control of perennial w eeds, woody and invasive species. Unlike the other herbicides, less than 50% of 2,4

- D is used in the crop segment (Fig ure 4

- 7).

Sou rce: ( US

- EPA, 2012c )

. Figure 4

- 8

. 2,4

- D Agricultural Usage by Crop Reporting District, 2006

– 2010

As can be seen in Figure 4

- 8, 2,4

- D is used predominantly in the Heartland , Prairie Gateway, the Southeast, and Northwestern U.S. 2,4

- D controls many broadleaf weeds including carpetweed, dandelion, cocklebur, horseweed, morning glory, pigweed sp., lambsquarters, ragweed spp., shepherd’s

- purse, and velvetleaf. It has little to no effective activity on grasses, including wheat, corn, and rice ( Industry Task Force II, 2005 ) . The states with the highest use in both periods from 2001

– 2005 and 2006

– 2010 were Texas, Oklahoma, Kansas and Montana, while the sites with the highest use in terms of total pounds applied in these periods were pastureland, winter wheat, and corn. The three highest use states are those with some of the highest amounts of pastureland. The sh are of 2,4

- D use on pastureland declined considerably between 2001

– 2005 and 2006

– 2010. The most non

- agricultural usage in terms of pounds applied as reported in 2003

Page 4

- 19and 2005 was by consumers for lawn use, direct application

, or as a fertilizer combinatio n ( US

EPA, 2012b )

. 2,4

- D is an ingredient in approximately 660 agricultural and home use products as a sole active ingredient or in conjunction with other active ingredients. In 2002, 2,4

- D was ranked as the third most used herbicide by active ingredient in the U.S. for all pu rposes (~46 million pounds), behind glyphosate (~102 million pounds) and atrazine (~77 million pounds) ( Gianessi and Reigner, 2006 ) . That same report found that the use o f 2,4

- D remained relatively steady from 1992 to 2002; Since that time, 2,4

- D use has been increasing from about 46 million pounds in 2002 to 64 million pounds in 2011 ( DAS, 2013b ) . In 2011, about 40% of 2,4

- D was used on crops, 38% was used on turf and ornamentals, and 22% was used on range and pasture and for industrial vegetation management such as to control unwanted vegetative growth on utility corridors, rights

- of

- way, roadsides, railroads, cemeteries, n on

- crop areas, and managed forest. It is also used to control aquatic and nuisance weeds, e.g., purple loosestrife ( Industry Task Force II, 2005 )

. 2,4

- D is very widely used for non

- agricultural use.

A major use today of 2,4

- D is in combination with other herbicides because it economically enhances the weed control spectrum of many other herbicides such as glyphosate, dicamba, mecoprop, and ALS herbicides ( US

- EPA, 2005 ) . Agriculturally, it is used on a variety of grass crops including pasture/hay, small grains (spring wheat, winter wheat, rice, sorghum, barley, millet, oats), corn, and sugar cane and on nut and fruit tree crops (almonds, apples, apricots, cherries, citrus, hazelnuts, nectarines, peaches, pears, pecans, pistachios, plums, and walnuts). It is also used in the production of some crops which are very sensitive to 2,4

- D such as soybean

, cotton, grapes where the 2,4

- D is used without applying it to the crop (see Table 4

- 7) . Table 4

- 7 lists the crops where at least 10% of the crop is treated with 2,4

- D and includes how many pounds of 2,4

- D were applied based on EPAs screening level usage analysis conducted in 2012 ( US

- EPA, 2012b )

. Although 2,4

- D is labeled for use in corn as a broad

- leaf weed herbicide, its use is limited beyond early seedling stages because it can produce significant malformations of

corn plants when applied at late s eedling stages ( Wright et al. , 2010 ) . When used in soybean production, 2,4

- D is applied as a pre

- plant burndown treatment

.

Page 4

- 20Table 4

- 7

. Agricultural U ses of 2,4

- D

Amount Used Percent Crop T reate d

Crop Pounds Active Ingredient

(lbs a.i. ) Average Maximum

1 Almonds 200,000 15 20 2 Apples 80,000 20 25 3 Apricots 2,000 10 25 4 Asparagus 5,000 10 30 5 Barley 500,000 25 40 6 Cherries 30,000 15 25 7 Corn 3,200,000 5 10 8 Cotton 700,000 10 15 9 Fallow 2,300,000 25 30 10 Grapefruit 10,000 10 25 11 Grapes 50,000 5 15 12 Hazelnuts (Filberts) 20,000 25 35 13 Nectarines 5,000 15 35 14 Oats 300,000 15 20 15 Oranges 100,000 20 30 16 Pasture 10,600,000 10 15 17 Peaches 30,000 20 30 18 Peanuts 50,000 5 10 19 Pears 10,000 15 20 20 Pecans 40,000 10 15 21 Pistachios 9,000 5 20 22 Plums 5,000 15 30 23 Prunes 20,000 15 25 24 Rice 300,000 10 15 25 Sorghum 900,000 20 30 26 Soybeans 2,900,000 10 15 27 Sugarcane 400,000 40 65 28 Sunflowers + 60,000 5 10 29 Sweet Corn 7,000 5 10 30 Tangelos 1,000 30 45 31 Tangerines 2,000 10 20 32 Walnuts 40,000 10 15 33 Wheat 5,900,000 30 65 Source: ( US

- EPA, 2012a )

. Page 4

- 21The current EPA

- approved use directions for 2,4

- D on corn allows a single pre

- e m ergent (burn down) application of 0.5

- 1 lb acid equivalents/acre (ae/ac) of 2,4

- D, a single post

- emergent application of 0.5 lbs ae/ac, and a single preharvest application of up to 1.5 lbs ae/ac. Seasonal

m ax i m u m use is 3 lbs ae/ ac/season ( DAS, 2010a )

. The current EPA

- approved use directions for 2,4

- D on conventional soybean allows a single
pre

- plant (burn down) application of 0.35

- 1 lb acid equivalents/acre (ae/ac) of 2,4

- D. There is a 7 to 30 day pre

- plant restriction, depending on the application rate used during the pre

- plant application ( DAS, 2010b )

.
When 2,4

- D is utilized in a burn down or pre

- plant treat m ent (corn or soybean), it is almost always c om bined in a tank m ix with glyphosate or other non

- selective herbicide and, when tank

- m ixed, 2,4

- D is generally recommended at the lower end of the rate range ~ 0.5 lbs ae/ac ( Nice et al. , 2013 )

In 2012, 97 m illion acr e s of corn was planted and 97.4 million acres were planted in 2013 ( USDA

- NASS, 2013 )

. Based on third party proprietary data obtained by DAS, in 2011, 5 .5

m illion p ounds of 2,4

- D were ap p lied to 9.5 m illion acres (10% of the corn crop) for an averag e of 0.57 lbs ae/treated acre while in 2009, 4 m illion pounds were used on 7.3 m illion acres (8.4% of the corn crop) for an average of 0 .55 lbs ae/treated acre (Table 4

- 8 ) ( DAS, 2012d )

.

Table 4

- 8

. 2,4

- D A pplied to C orn
Y ear Total A cres A cres trea t ed

w ith 2,4

- D Trea t ed A cres % of Total A cres Total Po und s

2,4

- D Pounds 2,4

- D / A cre Total App licatio ns / A cre

2009 86,382,000 7,300,000 8.4 4,000,000 0.55 2011 91,936,000 9,500,000 10 5,500,000 0.57 Source: ( DAS, 2012d )

. In 2012, 77 million acres of soybean was planted and 77.7 million acres were planted in 2013. 2,4

- D use as a pre

- plant burndown material has continued to increase between 2008 to 2011 where the percent of the crop treated has increased from 7% to 12% and total pounds used has increased from 2.7 million pounds to 4.9 million pounds (Table 4

- 9 ) ( DAS, 2012c )

.

Table 4

- 9

. 2,4

- D A pplied to S oybean

Y ear Total A cre s A cres trea t ed

w ith 2,4

- D Trea t ed A cres % of Total

A cres Total Po und s

2,4

- D Pounds 2,4

- D / A cre Total App licatio ns / A cre

2008 74,404,953 5,068,628 7 2,716,207 0.5 1.01 2009 77,584,979 7,637,880 10 3,680,330 0.4 1.01 2010 78,725,007 7,763,593 10 4,106,140 0.5 1.00 2011 74,835,007 8,832,324 12 4,893,146 0.5 1.00 Source: ( DAS, 2012c )

.

Page 4

- 22Current Qui z alofop Use DAS

- 40278

- 9 corn is resistant to q uizalofop

- P

- ethyl whereas conventional corn is sensitive. The “fop” herbicides (AOPP ACCase inhibitors) have been registered for crop use for more than 20 years ( USDA

- APHIS, 2010 ) . The “fop” herbicides traditionally have not been used to control weed species in cornfiel ds because, as a grass (Poaceae family) species, corn is damaged by AOPP ACCase inhibitor activity. The registration and use of “fop” herbicides has been primarily on broadleaf crops, such as soybean, to control grass weed species, although certain cereal plant varieties have a level of tolerance to some “fops” ( see DuPont, 2010 ) . According to the USDA National Agricultural Statistics Service (NASS ) Agricultural Chemical Use Database, “fop” type herbicides were used for weed contro l on at least 23 food crop species between 1990 and 2006, totaling more than 16 million pounds of active ingredient ( USDA

- NASS, 2011 )

. The AOPP herbicides inhibit chloroplastic ACCase , which catalyzes the first committed step in fatty acid biosynthesis, causing plant death ( Burton et al. , 1989 )

. There are three families of ACCase inhibitors, the “fops”, the “dims”, and the “dens” where Quizalofpr

- ethyl belongs to the “fops” family. The herbi cidal activity of quizalofop

- ethyl ester was first reported in 1983, and quizalofop

- ethyl was first approved for use in a registered herbic ide product in the U.S. in 1988 ( DAS, 2010b ; DuPont, 2010 )

. 1 However, all end use product registrations were cancelled prior to 1996 and it was replaced by the more active quizalofop

- P

- ethyl (pure R

- ena n tiomer of quizalofop racemic mixture), which first was approved for use in a registered product in 1990 ( DuPont, 2010 ) . Quizalofop

- P

- ethyl is a systemic herbicide that is absorbed from the leaf surface and translocated throughout the plant ( DAS, 2010b )

.
Most non

- graminaceous plants (dicots and sedges) are tolerant to quizalofop. Dicotyledonous plants contain a prokaryotic form of ACCase which is insensitive to “fop” herbicides. In contrast, monocotyledonous plants contain a sensitive eukaryotic form of ACCase in the plastid ( DAS, 2010a )

. This is the primary reason that the “fop” herbicides are generally good graminicides, with little activity on dicot plants. In addition, some gras s species, including some cereal crops and weeds (e.g., annual bluegrass and wild oats), are tolerant of some of these herbicides (i.e., clethodim, quizalofop, and others) due to their ability to metabolize the herbicides to inactive forms ( Devine and Shukla, 2000 ; Powles and Preston, 2009 )

. Quizalofop

- P

- ethyl is used as a selective post

- emergent herbicide for the control of annual and perennial grass weeds in 23 broadleaf food crop species. The currently registered uses of quizalofop

- p

- ethyl in clude canola, crambe, cotton, crops grown for seed, eucalyptus, dry beans (including Chickpea), dry and succulent peas, flaxseed, hybrid poplar plantings, lentils, mint (spearmint and peppermint), pineapple, ryegrass grown for seed, snap beans, soybeans, s ugar beets, sunflowers, and noncrop areas. Current allowable rates for this herbicide vary from 0.0172 to 0.344 lb ai/acre, depending on crop and weed conditions ( see EPA approved label for Assure II) ( DAS, 2010b ; DuPont, 2010 )

. Although quizalofop

- P

- ethyl is registered for use on soybean, it is not among the 10 mo st frequently used herbicides on this crop. It is sometimes used to eliminate vol unteer corn from

1 Reference to the DuPont Assure TM II label is for illustration only, and is not intended to infer any recommendation for the use of this product by APHIS or the USDA.

Page 4

- 23soybean fields. T he most frequently used ACCase inhibitor on soybean is clethodim , an herbicide in the “dim” family and the fifth most widely used herbicide in the Heartland, the Northern Crescent, and the Northern Great Plains. The “fop” herbicides traditionally have not been used to control weed species in cornfields because, like ot her grasses, corn is sensitive to ACCase inhibitors

. D A S

- 40278

- 9 corn, however is resistant to quizalofop.

Current Glufosinate Use

G lu f osin a te is a nons e l ec tive h er bi c ide th a t is us e d to c ont r ol g r a ss e s, s e d g e s a nd b r o a dl ea f

w e e ds. Sin c e it is a nons e l ec tive h e r bi c ide it inju r e s or kill s cr op pl a nts th a t it c ont ac t s. S e v era l

cr o p pl a nts h a ve b ee n modi f i e d b y ins e r ting a g e ne th a t p r odu ce s a n e n z y me w h i c h d e to x i f i e s g lu f osin a te b y c on v er ti n g the h e r bi c ide into a non

- ac tive f o r m. B a y e r C r op S c i e n c e h a s

r e g ist e re d g lu f osin a te f or use on g lu f osi n a te

- resistant cr ops in c luding corn and s o y b e a n. I gnite 280 S L Her bi c ide (E PA R e g

. N o

. 264

- 829) is a c omm e r c i a l l y a v a il a ble g lu f osin a te c ont a ini n g h e r bi c ide w ith di rec tions f o r use on g lu f osin a te

- resistant cr ops ( DAS, 2012a )

. Glufosinate herbicides contain the active ingredient phosphinothricin and are in the phosphinic acid family of herbicides. The herbicide acts by blocking the plant enzyme glutamine synthetase, which is responsible for nitrogen metabolism and for detoxi fying ammonia, a by

product of plant metabolism. The exposed plant dies by the over

- accumulation of ammonia ( US

- EPA, 2008 ) . First registered with EPA in 199 3, initial glufosinate end

- use products were designed for home owners; light industrial, non

- food users; and farmstead , weed

- control users ( OSTP, 2001 ) . Glufosinate, a water soluble herbicide, is approved for use on apples, berries, canola, corn, cotton, currants, grapes, grass grown for seed, potatoes, rice, soybeans, sugar beets, and tree nuts. Non

- crop areas where glufosinate is registered for use on include residential lawns and industrial and public areas. Products include Rely TM , RemoveTM, AEH TM

, Derringer TM , and Finale TM ( US

- EPA, 2008 ) . Ignite TM /Liberty TM glufosinate products are registered exclusively for selective over

- the

- top use on GE LibertyLink TM corn, cotton, canola, rice, and soybean.

In 2002, it was estimated that glufosinate use in the U.S. for all purposes was 982,324 lb a.i. ( Gianessi and Reigner, 2006 ) . Estimates of annual applications of glufosin ate in the U.S. indicate that approximately 1,000,000 lb a.i. were applied to agricultural land with the highest percentage (90 percent) used on corn ( United States Geological Survey, No Date ) . Based on its proprietary data for the period from 2007

– 2011, EPA estimated that the highest annual agricultural uses of glufosinate are in corn (1.3 million lbs), almonds (200,000 lbs), cotton (200,000 lbs), grapes (200,000 lbs), canola (100,000 lbs) and soybeans (100,000 lbs) ( US

- EPA, 2012d ) . With the commercial availability of glufosinate

- resistant LibertyLink TM soybean beginning in 2009, glufosinate use on soybeans has increased. Glufosinate

- resistant soy bean accounted for less than 1 percent of soybean acreage planted in the U.S. in 2009 with approximately 72,000 lb ai glufosinate applied. In 2012, the planted acreage of glufosinate

resistant soybeans increased to 3.9 percent, and glufosinate use rose to approximately 1,536,000 lb ( DAS, 2012a ) Table 4

- 3 . The map in Figure 4

- 9 shows the use of glufosinate from 2009 prior to the use on soybean. (A more recent version is/is not available). At that time, most use of glufosinate was concentrated in the Midwest.

Page 4

- 24Figure 4

- 9

. Estimated Annual Agricultural Use of Glufosinate in the U.S

. Source: ( USGS, 2009 )

Due to its nons e l ec tive a c tivi t y , g lu f osin a te h a s a wee d m a n a g e m e nt sp e c t r um simil a r to g l y phos a te a nd its use h a s g r o w n, p ar ti c ul a r l y in a rea s w ith g l y phos a t e

- re s i st a nt wee ds ( Southeast Farm Press, 2012 )

. In the southeast in 2011, glufosinate was the ninth most frequently used herbicide on soybean. G lu f osin a te resistance in E nlist TM s o y b ea n e n a bl e s u se of g lu f osin a te a s a n h e r bi c ide on c omm erc i a l l y g r o w n s o y b ea ns but a lso p r ovid e s u se a s a

s e l e c tion a g e nt in b ree di n g p r o g ra ms a nd s ee d a mpli f i c a tion ( DAS, 2010b )

.
G lu f osin a te

- resistant s o y b ea ns a r e a mo r e r e ce nt i n t r odu c tion th a n g l y phos a t e

- resistant

s o y b e a ns. T he numb e r of ac r e s pl a n t e d to g lu f osin a te

- resistant s o y b ea ns h a s g r o w n st e a di l y but is still a v e r y sm a ll fr a c tion of tot a l s o y b e a n a cre s. A v e ra ge s ea son a l use ra te is a b o ut a h a lf pound p e r acr e w ith just ov e r 1 a pp l i ca tion p e r a cr e m a d e

. G lu f osin a te ca n a lso be us e d a s a p r e

- pl a nt ( bu r n do w n) t rea tm e nt on c on v e ntion a l a nd g lu f osin a te

- resistant s o y b ea n, h o we v e r volume e stim a t e s f or this use h a ve a hi g h d e g re e o f un c er t a in t y ( DAS, 2012a )

. F o r the y e ar s 200 9

- 2011on l y a tot a l of 46,000 lbs wer e u s e d in a p r e

- pl a nt t r ea tm e nt a nd 75% o f those pounds we r e us e d in 2 0 11.

Although glufosinate provides an additional means of weed control, it is not as versatile as glyphosate. For example, g lu f osin a te n ee ds to be a ppli e d to sm a ll e r wee ds w ith f in e r d r opl e t si z e s a nd l a r g e r c a rr i e r volum e s to ac hi e ve a d e qu a te c o n t r ol. This is in part because, unlike glyphosate which translocates readily throughout the plant, glufosinate h a s limit e d mobili t y and
t hus re qui r es b e tt e r c ov er a ge f or c ont r ol ( h e n c e the l a r g e r ca rr i e r vol u m e s a nd sm a ll e r d r opl e t

s i z e s )

. Page 4

- 25Application rates of glufosinate range significantly by use pattern, with the highest rate allowed for broadcast (ground) spray applications, at 1.5 lbs a.i./ A, on orchard nuts and fruits, grapes, grasses grown for seed, and golf course turf. On the low end of application rates, labeled uses of glufosinate on turf and patio are at 0.03 lbs a.i./A. Multiple applications are allowed by most labels, although the interval is not generally specified ( US

- EPA, 2008 ) . The EPA

- registered use of glufosinate on LibertyLink TM (i.e., glufosinate

- resistant ) soybean includes an initial application of glufosinate no higher than 0.66 lb a.i./A (36 fl oz/A) with a minimum of 0.40 lb a.i./A (22 fl oz/A). A single second application of glufosinate up to 0.53 lb a.i./A (29 fl oz/A) is approved on LibertyLink TM soy beans, with a seasonal maximum rate of 1.2 lb a.i./A (65 fl oz/A) permitted. Glufosinate applications on LibertyLink TM soybean should be made from emergence up to but not including the bloom growth stage and within 70 days of harvesting soybean ( Bayer CropScience, 2011 )

. Current Glyphosate Use Current glyphosate use direct ion s approve d b y EP A fo r us e o n g l yphosate

- resistant cor n allow a

m ax i m u m pre

- e m ergence application a m ount of 3.7 lbs glyphosate ae/ac, and two post

- e m ergent applicati o ns each at 1

. 125 lbs gly p hosate ae/ac (total 2.25 lbs ae/ac). A n additional pre

- harvest applic a tion of 0.77 lbs ae/ac can be m ade. Total seasonal use rate is 6 lbs glyphosate ae/ac

. Application of glyphosate to soybean is simil ar with the exception that post

- emergent applications fr o m 0.75 to 1.5 lbs g l y pho s a te ae / a c ( tot a l 2.25 lbs a e / ac /s ea so n ) can be made.

Third party proprietary m arket research data indicate that the percentage of glyphosate

- resistant

corn acres has grown over the last four years (Table 4

- 10 ). Total pounds of glyphosate applied to corn have also increased during this ti m e where the percentage of the crop has increased from 77% treated in 2008 to 90% treated in 2011. In contrast, acres of soybean treated ha ve remained fairly constant at 94

- 96% of the crop (Table 4

- 11) . The application rate and the total applications/acre have remained fairly uniform for both crops despite the increase in glyphosate resistant weeds.

Table 4

- 10

. Glyphosate Use on Glyp h osate

- Resistant Corn Year Total Acres Gly

- Tol Acres Gly

- Tol as % o f Total Acres Total Pounds Gly Lbs Gly/Ac r e Total Applicatio n s/ Acre 2008 86,705,017 66,854,236 77 67,760,400 1.06 1.29 2009 86,409,977 71,071,345 82 68,621,113 1.05 1.28 2010 87,230,005 75,958,684 87 75,582,434 1.11 1.31 2011 91,620,001 82,163,813 90 85,671,957 1.17 1.33 Source: ( DAS, 2012d )

Page 4

- 26Table 4

- 11

. G ly ph o s ate Us e on Gly ph o s ate

- Resistant S oy b ean Ye ar To t al Acres G ly

- Tol Acres G ly

- Tol as % o f To t al Acres To t al P ounds G ly Lbs G ly/ Ac r e To t al A ppli c a t ions/ Acre 2008 74,404,953 71,592,624 96 95,398,687 1.32 1.58 2009 77,584,979 73,219,835 94 96,415,627 1.30 1.55 2010 78,725,007 74,059,182 94 102,162,527 1.38 1.58 2011 74,835,007 71,734,538 96 100,121,452 1.40 1.54 Source: ( DAS, 2012c )
Glyphosate use is concentrated heavily in the Midwest, along the Mississippi River, the Southeast seaboard, and the Central Valley of California as depicted in Fig ure 4

- 10

.

Figure 4

- 10

. Estimated Annual Agricultu ral Use of Glyphosate in the U.S.

Notes: Map represents average annual pesticide use intensity expressed as average weight (in pounds) of a pesticide applied to each square mile of agr icultural land and typical use patterns over the 5

- year period of 1999 through 2004. Source: ( USGS, 2009 ; United States Geological Survey, No Date )
Changes in 2,4

- D and Glyphosate Use for Enlist Duo TM Herbicide Proposed new use rates of 2,4

- D and glyphosate, the active ingredients in the new DAS Enlist DuoTM herbicide formulation, on Enlist TM corn and soybeans are detailed in Appendix 8.
Page 4

- 27Projected 2,4

- D U se in Corn and Soybean under the No Action and Action Alternatives

No Action Alternative

In the past 3 years, there has been a 38% increase in the amount of 2,4

- D applied to corn (Table 4

- 8) and an 80% increase in the amount applied to soybean over the past 5 years (Table 4

- 9 ) ( DAS, 2012d ; DAS, 2012c ) . These increases are due to the increased fraction of the crops treated and the increase in acreage of both crops. Although the acreage of corn and soybean is not expected to increase substantiall y beyond current levels, the percentage of the crop treated is expected to continue to increase as glyphosate resistant weeds become more widespread. Thus

, under the No Action Alternative, an increase in baseline use of 2,4

- D on corn and soybean is expecte d. Historically, the highest recorded use of 2,4

- D is its application to 14% of the U

. S

. corn acres in 1994 ( USDA

- NASS, 2011 ) which would result in a further 4% increase in 2,4

- D use in corn. However, APHIS sees no reason that this share is an upper limit and 2,4

- D use in either crop as a pre

- plant burndown could reasonably be expected to follow the distribution of glyphosate

- resistant weeds in the corn and soy bean crop.

Third

- party proprietary market research demonstrates that approximately 98% of glyphosate

resistant soybean acres receive at least one glyphosate application (burn down and/or post emergent). A small population of farmers (~4%) that purchase glyphosate

- resistant soybeans elect not to make a pos t

- emergent glyphosate application. The market research also indicates that 22% of planted soybean acres currently receive a burn

- down (pre

- plant or pre

- emergence) herbicide application. For corn, ~10% of farmers that purchase glyphosate

- resistant c o rn el ect not to m a ke a post

- e m ergent glyphosate application. T he m arket re s earch also indicates t h a t 22 %

o f planted corn acres currently receive a burn

- down (pre

- plant or pre

- e m ergence) herbicide application.

Using third party m arket data, DAS has esti m ated that 5% of U

. S

. c orn or soybean acreage had glyphosate

- resistant weeds in 2010, and that the percentage would grow to 10% of soybean/corn acreage by 2015 and to 30% by 2020 (Figure 4

- 13 ). This is consistent with but less aggressive than pre d ictions m ade by other others, ( Foresman, 2009 ; Farm Industry News, 2013 )

. Assuming that by 2020, 30% of corn and soybean fields will be infested with glyphosate resistant weeds, it is reasonable to assume that up to 30% of corn and soy gr owers will use 2,4

- D on their crops for burndown applications

. Currently 12% of the soy crop is treated with 2,4

- D (Table 4

- 9) . If that percentage increases to 30%, 2,4

- D use on soy would be expected to increase from 5.4 to 13.5 million pounds ( a factor o f 30/12=2.5). Likewise, 10% of the corn crop is treated with 2,4

- D (Table 4

- 8) . If 30% were treated, the amount of 2,4

- D applied would increase from 5. 4 million pounds to 16.2 million pounds. Assuming 2,4

- D use does not increase in other
crop or non

- crop applications, the total applied to crops is predicted to increase from 25.6 million pounds to 44.5 million pounds resulting in a 74% increase in crop use of 2,4

- D and a 29% increase in total 2,4

- D use (Table 4

- 14 ) under the No Action Alternative

.

Page 4

- 28Source: ( DAS, 2011a )

. Figure 4

- 11

. Projected corn and soybean acres infested with glyphosate resist a nt weed s.

Action Alternatives

There is considerable uncertainty regarding the projected use of 2,4

- D on DAS

- 40278

- 9 corn
, DAS

- 68416

- 4 soybean, and DAS 44406

- 6 soybean should all be granted non

- regulated status. The adoption rate would depend on the availability of the traits in high performing varieties, the extent to which weeds are difficult to control with existing herbicides, cost of the new product relative to existing varie ties, to name a few.

EPA has approved 2,4

- D for use on other major agricultural crops at rates greater than those proposed for DAS

- 68416

- 4 soybean, DAS 44406

- 6 soybean or DAS

- 40278

- 9 corn. The proposed maximum 2,4

- D application rate for soybean is the sa me as that currently approved for use on field corn and popcorn ( US

- EPA, 2005 ) , which are typically grown in the same areas as soybeans and often in the same fields in rotation with soybean. U tili z ing the histo r i ca l l y

c onsist e nt d a ta fr om the c u rre nt a nd b r o a d u s e of g l y phos a te on DA S

- 40278

- 9 corn (Table 4

- 10), DAS has estimated that farmers who grow Enlist TM corn will use an average of 0.875 lbs 2,4

- D ae/ac/application with an averag e o f 1.3 3 applications per season. Similarly, u tili z ing the histo r i ca l l y c onsist e nt d a ta fr om the c u rre nt a nd b r o a d u s e of g l y phos a te on s o y b e a n (Ta b l e 4

- 11 ) plus f i e ld t r i a l d a ta on w e e d c o nt r ol w ith v ar ious h er bi c i de a ppli ca tion ra t e s, DA S h a s e stim a t e d th a t f ar m er s w ho g r ow Enlist TM s o y b ea n w ill use a n a v e ra g e o f 0.875 lbs 2,4

- D ae / a c / a ppli ca t i on

w ith a n a v e ra g e of 1. 5 4 a ppli ca tions p e r s e a son ( in c lud e s bu r n do w n a nd post e m e r g e nt applications )

. T he a ppli ca tion r a te of 0

. 875 lbs 2,4

- D ae / a c is the midpoint b e t wee n the m e dium

Page 4

- 29a nd hi g h r a t e s a llo we d on the E nlist D uo TM l a b e l a nd is c onsist e nt w ith the g l y phos a te ra te n ee d e d f

or wee d c ont r ol. A s E nlist D uo TM c ont a ins a n ~ 1:1 r a tio of 2,4

- D a nd g l y phos a te , n ear l y id e nti c a l

ra t e s of 2,4

- D and g l y phos a t e w ill be a ppli e d.

DAS provided to APHIS three projections of 2,4

- D use in corn and soybean:

Scenario 1 assu m es growers will o n ly apply Enlist Duo TM to D A S

- 40278

- 9 corn, DAS

- 68416

- 4 soybean, or DAS 44406

- 6 soybean where growers are facing or actively trying to prevent the establishment of glyphosate

- resistant weeds. Addition a lly t h is scenario also assu m es that all far m ers with corn or soybean acres that have glyphosate resistant weeds will plant DAS

- 40278

- 9

corn or DAS

- 68416

- 4/ DAS 44406

- 6 soybeans and will use E n list Duo TM herbicide. This is an overestimate of the use of 2,4

- D given the fact that other weed control options are available. Assu m ing that m in i m al additio n al acreage would be treated to prevent g l yphosate resistant we eds from beco m ing established, and using the a ssu mptions set f orth ab o ve reg a rding tot a l corn or soybean acres, application rates and ap p lications per season, the following fo r m ula was used to calculate tota l lb s o f 2,4

- D a e tha t m i gh t be used on DAS 40278

- 9 corn
, DAS

- 68416

- 4 soybean, or DAS 44406

- 6 soybean:

Corn

92MM acres x 30% resistant weeds (in 2020) x .875 lbs ae/ac/application x 1.33 applications/season = 32MM lbs 2,4

- D ae per yea r (Table 4

- 14)

. This represents an approxi m ate six

- fold increase in 2,4

- D use on corn in 2020 co mpared to the volu m e of 2,4

- D currently used on corn in 201 1 and a 100 % increase compared to the volume predicted to be used under the No Action Alternative for 2020.

Soybean

76MM acre s x 30% re si s t a nt wee ds ( in 2020) x .8 75 lbs ae / ac / a ppli c a tion x 1.54

a ppli ca tions/s ea son = 3 1 MM lbs 2,4

- D a e p e r y e a r (Table 4

- 14)

. T his re p re s e nts a n

a p p r o x im a te six

- f old in crea s e in 2,4

- D u s e in 2020 c omp are d to t h e volume of 2,4

- D

c u rr e n t l y us e d on s o y b ea n in 2011 and a 130 % increase compared to the volume predicted under the No Action Alternative for 2020.

S ce nario T wo. T he s ec ond s c e n ar io a ss u m e s that all acres of DAS 40278

- 9 corn
, DAS

- 68416

- 4 soybean, or DAS 44406

- 6 soybean w ould r ece ive a p p li ca tions of E nlist D uo TM

, re g ar dl e ss of

wee d c ont r ol n ee d, a nd thus r e l i e s on e stim a t e s of what t he p r oj ec t e d m ar k e t share of these two
crops w ill b e :

DA S s e lls corn and s o y b e a n s ee d t h r ou g h its subsidi a r y s ee d c omp a ni e s, i. e ., M y c o g e n S ee ds, R e n z e S ee ds, Da i r y l a nd S e e d, P f ist e r S ee ds, B r odb e c k S ee ds, Tr iumph S ee d, P ra i r ie B r a nd S ee d

a nd H y l a nd S e e ds. T h r o u g h t h e se subsidi ar i e s, DA S c u rre nt l y h a s <5% of the m arket share for field corn and silage corn and < 3 % of the m ar k e t sh a r e f or s o y b e a n. A t this tim e , DAS is not planning to breed DAS

- 40278

- 9 corn into all of its corn hybrids, so DAS

- 40278

- 9 corn would occupy considerably less than DAS’s current < 5% of the m arket. Similarly, DA S is not pl a nning to b r e e d D A S

- 68416

- 4 s o y b ea n into a ll of its s o y b ea n v ar i e ti e s, so Enlist TM s o y b e a n

w ould o c c u p y l e ss th a n DA S ’ s c u r r e nt < 3% of the m ar k e t. H o w e v er , f or p u rpos e s of this

Page 4

- 30e stim a t e , 5% and 3% w ill be us e d a s a minimum pot e nti a l for DAS

- 40278

- 9 corn and Enlist TM

s o y b e a n acr ea g e, respectively.

DA S is int ere st e d in a nd is pu r suing li ce nsi n g a g r ee m e nts w ith a ddition a l corn and s o y b e a n s ee d

c omp a ni e s to b r e e d DAS

- 40278

- 9 corn and DA S

- 68416

- 4 or DAS

- 44406

- 6 s o y b ea n into a licensee’s corn and soybean ger m pla s m, respectively. T o d a t e , t wo li ce nsing a g r e e m e nt h a ve b ee n m a de re p r e s e nti n g ~ 35% of the soybean m ar k e t but no agreements have been made for

corn. T h r ou g h n a t u ra l g r o w th a nd th e se li ce nsi n g a rra n g e m e nts it is rea son a b l y possible th a t, a t

m a tu r i t y , a pp r o x im a t e l y 45% of the corn and s o y b ea n g er mpl a s m c ould h a ve the E nlist TM t ra it and these corn and s o y b ea n v ar i e ti e s could be pl a nt e d on up to 45% of the tot a l corn and s o y b ea n

a c re a g e . Due to the technical as p ects of corn and soybean seed breeding, rapid i m prove m ent of ger m pla s m and stacking with other traits, this level of adoption of DAS

- 40278

- 9 corn
, DA S

68416

- 4 soybean, or DAS

- 44406

- 6 s o y b ea n is esti m ated to take 5

- 10 years to reach m aturity ( m aturity i n 2018

- 2023)

.
Corn :
Assuming application rates of 2,4

- D are as described above: an average of 0.875 lbs ae/ac/application with 1.33 a pplications per y ear and 90 % of acres esti m ated (based on current glyphosate application information from proprietary third party data that only 90% of glyphosate resistant corn is sprayed with glyphosate ) :
At present market share of 5%, 2,4

- D use on corn is expected to double comp ared to 2011:

92MM acres x 5 % m arket share x 90% DAS

- 40278

- 9 corn acres treated x 0.875 lbs ae/ac/ap p lication x 1.33 applications per DAS

- 40278

- 9 corn acre = 4,709,250 additional lbs 2,4

- D ae per year compared to 5.4 million pounds in 2011

. At a market share of 45%, 2,4

- D use on corn might increase 8 fold compared to 2011 levels.

92MM acres x 4 5 % m arket share x 90% DAS

- 40278

- 9 corn acres treated x 0.875 lbs ae/ac/application x 1.33 esti m ated applications per DAS

- 4078

- 9 corn acre = 43,361,325 lbs 2,4

- D ae per year.
Soybean :
Assuming a ppli ca tion ra t e s of 2, 4

- D ar e a s d e s c r ib e d a bo v e : a n a v e ra g e of 0.875 lbs

ae / ac / a ppli c a tion w ith 1.54 a ppli ca tions p e r y e ar and 100% of acres are treated:

At a market share of 45%, 2,4

- D use on soybean is expected to increase approximately nine

- fold compared to 2011 levels.

76MM acre s x 45% m ar k e t sh ar e x 100% DA S

- 6 8 416

- 4 s o y b ea n a c r e s t rea t e d x 0.875 lbs

ae / ac / a ppli c a tion x 1

. 54 e stim a t e d a ppli ca tions p e r Enlist TM s o y b e a n ac r e = 46,084,500 lbs 2,4

- D

a e p e r y e a r.

Scenari o Three : The third scenario as s u m es that all curre n t gly p hosate

- resistant corn and soybean acres would be planted to hybrids that also c ontain the DAS

- 40278

- 9 corn
, DAS

- 68416

- Page 4

- 314 soybean , or DAS 44406

- 6 soybean traits. This is an unrealistically high esti m ation but provides

an uppe r confidenc e leve l o n 2,4

- D volume

. It is unrealistic to assume that all glyphosate resistant corn and soybean will be replaced by the Enlist TM products. First, not all growers will be f

aced with glyphosate resistant weeds and such growers may have little economic incentive to adopt Enlist TM corn or soybean. Second, other herbicide resistant soybean varieties are on or expected to appear on the market, such as glufosinate, dicamba, isoxafl utole, and mesotrione resistant varieties so competition is expected to reduce market share. Third, corn is already resistant to 2,4

- D and dicamba for at least part of its growth cycle , and thus some growers may not value this trait in corn. Even with thi s extre m e assu mption, the esti m ated 2,4

- D volu m e is only a 17

- fold increase in 2,4

- D use on corn and a fourteen fold increase on soybean compared to the current use of 2,4

- D on existing varieties, calculated as follows:

From Table 4

- 10
, 82MM acres of the 9 2 M M tota l cor n acre s a r e planted to glyphosate

- resistnat

corn. Using the sa m e application information and other assu mptions used in the previous two scenarios, the 2,4

- D v o lu m e can be esti m ated as follows:

82MM glyphosate

- resistant acre s x 90 % DAS

- 40278

- 9 cor n acre s treate d x 0.87 5 lbs ae/ac/application x 1.33 esti m ated applications per DAS

- 4078

- 9 corn acre = 85,884,750 lbs 2,4

- D per year.
For soybean, at least 32% of the market (24MM acres) will not contain the DAS

- 68416

- 4 or DAS

- 44406

- 6 soybean traits, d ue to one developing technology that will be a direct competitor to the Enlist TM Weed Control System. Correcting for this market share, the maximum acreage that might be planted to DAS

- 68416

- 4 or DAS 44406

- 6 soybean traits is 52MM acres (76MM

24MM). Using t he previously applied assumptions for soybean, 2,4

- D volume is estimated as follows:

52MM glyphosate

- resistant acres x 100% DAS

- 68416

- 4/DAS 44406

- 6 soybean acres treated x 0.875 lbs ae/ac/application x 1.54 estimated applications per DAS

- 68416

- 4/DAS

- 44406

- 6 soybean acre = 70,070,000 lbs 2,4

- D per year

.
Other Estimates of 2,4

- D U se on Enlist TM C orn and S oybean.

Benbrook ( Benbrook, 2012 ) projected much higher 2,4

- D use rates on DAS

- 40278

- 9 cor n (30 fold) than any of the scenarios noted above. One major discrepancy is his assumption that 2,4

- D use on corn may increase to 55% of planted corn acres by 2019. This is a much larger estimate than DAS made (30

- 45%) based on its potential for licensing of its technology to corn s eed breeders. He also assumes a much higher use rate. Both Benbrook and DAS estimate a comparable application rate of 0.84 and 0.875 lbs/acre, respectively. However Benbrook projects that the frequency of applications will increase to 2.3 applications/year

, while DAS estimates the average number of applications to be 1.33 per year. Historically, corn growers have used 3

- 4 different herbicide chemistries even after the introduction of Roundup Ready corn. If growers continue to use other modes of action, it is unlikely that 2,4

- D applications will rise to 2.3 applications/year. Therefore, USDA considers the Benbrook projection to be an overestimate.

Summary of Projected 2,4

- D Use

Page 4

- 32The information from the calculations described above are summarized in Table 4

- 14 . Under the No Action Alternative, 2,4

- D use is expected to increase to 82.8 million pounds for all uses of 2,4

- D where 44.5 million pounds are applied to crops. The predicted 2020 crop usage constitutes an increase of nearly 75% compared to the volum e of 2,4

- D used on crops in 2011 (44.5 million pounds vs25.6 million pounds).

Under the Action Alternatives, three scenarios were considered (I, II, and III). Under Scenario I, a six fold increase in 2,4

- D use is estimated for both corn and soy bean compar ed to current levels. Under Scenario II, an 8 fold increase is estimated for corn and a 9 fold increase is estimated for soy bean . Under Scenario III, a 17 fold increase is estimated for corn and a 14 fold increase is estimated for soy bean. These c alculatio ns are summarized in Table 4

- 14 . Total crop 2,4

- D use is predicted to range from 9 8 .6 million pounds to 214.5 million pounds , depending on the scenario and Alternative

. Compared to levels of 2,4

- D used in 2011, the predicted increase in crop 2,4

- D use und er the Preferred Alternative would be approximately 204% to 588%. However compared to the No Action Alternative estimation for 2020 , the increase on crop use i s estimated to range from 75%

- 296%.

Under Alternative 3 where only corn would be deregulated, the increase of crop 2,4

- D use predicted under the three scenarios ranges from an increase of 136% 370% compared to the current situation. Relative to the No Action Alternative estimation for 2020, the increase ranges from 36% to 169%.

Under Alternative 4 , where only soy would be granted non

- regulated status, the increase of crop 2,4

- D use predicted under the three scenarios ranges from an increase of 201% 316% compared to the current situation. Relative to the No Action Alternative estimation for 2020 , th e increase ranges from 39% to 139%.

Note that even under S cenario I which predicts the smallest fold increase in 2,4

- D use, USDA considers the estimate to be high because it assumes an unrealistically high market share. Thus while 2,4

- D use is expected to increase under the Action Alternatives, the difference from the predicted No Action is expected to be less than the 75 % increase noted in Table 4

- 14

. Currently, 2,4

- D is the third most frequently used herbicide in the U.S (an estimated 64 million pounds we re used in 2011) after glyphosate (an estimated 225 million pounds were used in 2011) and atrazine (an estimated 77 million pounds were used in 2011) (Table 4

- 15). Levels of atrazine use have stayed fairly constant over the past decade but use of glyphosat e and 2,4

- D have continued to increase. Based on the assumptions made, it is estimated that 2,4

- D use will surpass atrazine use by 2020 under both the No Action and Action Alternatives.

Page 4

- 33Table 4

- 12

. Projec ted 2,4

- D U se U nder Four Alternative s. Alternative 2 (Enlist TM corn + soybean)
actual 2,4

- D (millions of pounds) projected 2,4

- D

use in 2020 under No Action (NA) Alternative Projected 2,4

- D use based on DOW estimates for 2,4

- D use on 2,4

- D corn and soybean

(millions of pounds)

2011 increased burndown 1 Scenario I 2 Scenario II 3 Scenario III 4

crops 25.6 44.5 77.8 104.1 176.2
t urf and ornamental 24.3 24.3 24.3 24.3 24.3 range/pasture/industrial management 14.0 14.0 14.0 14.0 14.0

corn 5.4 16.2 32.0 43.3 85.9 soybean 5.4 13.5 31.0 46.0 70.1 total 2,4

- D 64.0 82.8 116.1 142.4 214.5 % increase in crop 2,4

- D relative to No Action 2020 75% 134% 296% % increase in total 2,4

- D relative to No Action 2020 40% 72% 159%

Alternative 3 (Enlist TM corn only)

2011 increased burndown 1 Scenario I 2 Scenario II 3 Scenario III 4

crops 25.6 44.5 60.3 71.6 119.6 Turf and ornamental 24.3 24.3 24.3 24.3 24.3 range/pasture/industrial management 14.0 14.0 14.0 14.0 14.0

corn 5.4 16.2 32.0 43.3 85.9 soybean 5.4 13.5 13.5 13.5 13.5 total 2,4

- D 64.0 82.8 98.6 109.9 157.9 % increase in crop 2,4

- D relative to NA 2020 36% 61% 169% % increase in total 2,4

- D relative to NA 2020. 19% 33% 91%

Page 4

- 34Alternative 4 Enlist TM (soybean only)

2011 increased burndown 1 Scenario I 2 Scenario II 3 Scenario III 4

crops 25.6 44.5 62.0 77.0 106.5 Turf and ornamental 24.3 24.3 24.3 24.3 24.3 range/pasture/industrial management 14.0 14.0 14.0 14.0 14.0

corn 5.4 16.2 16.2 16.2 16.2 soybean 5.4 13.5 31.0 46.0 70.1 total 2,4

- D 64.0 82.8 100.3 115.3 144.8 % increase in crop 2,4

- D relative to NA 2020 39% 73% 139% % increase in total 2,4

- D relative to NA 2020. 21% 39% 75%

1 Assumes 2,4

- D applied to 30% of corn and soybean crop as preplant burndown

. 2 I estimate (30% glyphosate resistant weeds) = 6X current soy and corn use.

3 II estimate (DAS 45% market share corn and soy) = 9x current soy and 8X current

corn
4 III estimate (all corn and soy less competitor market share) =14X current soy and 17X current corn Source: ( DAS, 2013d )

.
Table 4

- 13

. Top T hree H erbicides

- Total Crop Use in 2002, 2011 and E stimated U se U nder Alternatives (millions of lbs )

2002 2011 2020 (No A ction) 2020 (Preferred ) 2020 (Alt 3) 2020 (Alt 4) glyphosate 102 225 225 225 225 225 atrazine 77 77 77 77 77 77 2,4

- D 40 64 83 116

- 215 99

- 160 100

- 145 Source: ( DAS, 2013d )

. Projected use of Qui z alofop on DAS 40278

- 9 Corn
Changes in Qui z alofop Use Directions w ith Enlist TM W eed Control System Quizalofop is currently registered for use on soybean and no changes in the use of quizalofop on soybean are projected.

Page 4

- 35Quizalofop is not yet registered for use on corn. It’s use as a post

- emergent herbicide on corn is a proposed new use 2 ( DAS, 2010b ) . The petitioner has indicated that “fop” herbicides could be used to maintain seed purity in DAS

- 40278

- 9 corn breeding nurseries, hybrid production fields, and generally for the control of grass weeds in corn. Table 4

- 16 provides a summary of the current labeled uses of quizalofop in comparison with proposed application rates and directions for use on DAS

- 40278

- 9 corn.
In current registered uses of quizalofop, the EPA has approved single application rates ranging from 0.034 to 0.082 lbs ai/acre (38 g ai/ha to 92 g ai/ha), depending on the weed species, with the highest maximum seasonal application rate being 0.206 pounds ai/acre (231 g ai/ha) for weed control in mint ( DAS, 2011b ) . Upon EPA a pproval of the herbicide registr a tion a m end m ent, a quiz a lofop herbicide (e.g., Assure II ) would be available for use on DAS

- 40278

- 9 corn. Whether used as a selection agent or as a n her b i c ide, the proposed use dir e ction s woul d essentially be the sa m e. The proposed directions for u s e o f quizalofo p o n DAS

- 40278

- 9 cor n woul d allow up to two post e m ergent applications from the V2 to V6 growth stage (Figure 4

- 14)

. Application rates are 0.034

- 0.082 lbs ai/ac. The total amount that could be applied in a season is 0.082 lbs ai/ac ( DAS, 2011b ) . The m ax i m u m s easonal rate for quizalo f op on DAS

- 40278

- 9 corn would be less than or equal to the m axi m u m seasonal rate on the la b el f or all o t her crops. DAS

40278

- 9 corn has proven tolerant to quizalofop post

- emergent application rates of up to 184 g ai/ha (0.164 lbs ai/acre) in field trials ( DAS, 2011c ) . The proposed maximum application rate is also the seasonal maximum application rate ( DAS, 201 1c ) . This maximum application rate is less than that currently approved for use of quizalofop for control of grassy weeds in soybeans and cotton, where a seasonal maximum application rate of 139 g ai/ha (0.124 lb ai/acre) is approved ( DAS, 2011c )

.
Table 4

- 14

. Comparison of Current and Proposed Application Rates for Quizalofop

Crop Stage Current Use Pattern for Quizalofop on Soybeans and Cotton Proposed New Use on DAS

- 40278

- 9 Co rn

Maximum Application Rate (lb/acre) 1,2 Directions and Timing Maximum Application Rate (lb/acre) 1,2 Directions and Timing

Post

emergence 0.082 Apply 0.034 to 0.082 lb/acre per application. Do not exceed a total of 0.124 lb/acre per 0.034 to 0.082 Apply 0.034 to 0.082 lb/acre per application from V2

– V6 Growth stages. Do not make more than 2 applications. Do not exceed a total of

2 As required under FIFRA, metabolism and residue data, along with proposed labeling changes, will be submitted to the EPA for the use of “fop”

- type herbicides (specifically q uizalofop) in DAS

- 40278

- 9 Cornfield s (page 18 of the Petition). Under FIFRA, it is unlawful to use an herbicide “in a manner inconsistent with its labeling” without an experimental use permit issued (7 U.S.C. 136j). Quizalofop is currently under registration review (http://www.epa.gov/opp srrd1/registration_review/) by the EPA with a Final Decision expected in 2013 (EPA

- HQ

OPP

- 2007

- 1089 at http://www.regulations.gov , accessed 3/2011).

Page 4

- 36Crop Stage Current Use Pattern for Quizalofop on Soybeans and Cotton Proposed New Use on DAS

- 40278

- 9 Co rn

Maximum Application Rate (lb/acre) 1,2 Directions and Timing Maximum Application Rate (lb/acre) 1,2 Directions and Timing

season. 0.082 lb/acre per season. Do not apply later than V6 growth stage. Total Annual Maximum Application 0.124

--- 0.082

---

So urce: ( DAS, 2010a )

. Notes: 1. Active ingredient. 2. 1 lb/acre is the equivalent of 1,120 g/hectare.

Source: ( DAS, 2012b )

. Figure 4

- 12

. Proposed Use P attern of Quizalofop on DAS 40278

- 9 Cor n

Page 4

- 37Under the No Action Alternative and Alternative 4, Enlist TM corn would not be deregulated and quizalofop c ould not be used on currently available corn varieties due to its inherent sensitivity. No changes are anticipated in the use of quizalofop on soybean.

Under the Preferred Alternative and Alternative 3, DAS

- 40278

- 9 corn would be deregulated. Because, unlike all other cor n, DAS

- 40278

- 9 corn is resistant to quizalofop, new uses for quizalofop may arise including the control of glyphosate resistant grasses in corn. A determination of nonregulated status of DAS

- 40278

- 9 corn, with EPA

- approved use of quizalofop on corn, has the potential to result in an increase in the annual amount of quizalofop

use . Although si x grass species have developed resista n ce to glyphosate in the US (Jungle rice, G oosegrass, Italian Ryegrass, Rigid Ryegrass, Annual Ryegrass and J ohns on grass), glyphosate remains an effective grass herbicide because the acreage of the affected area is still small. Hence, in the near future it is not expected that quizalofop will be used to control grass weeds in corn. One of the major uses of quizalof op is to control volunteer corn in soybean. It is expected that this use of quizalofop to control volunteer corn will decrease on farms that have adopted DAS

40278

- 9 corn, under the Preferred Alternative and Alternative 3

.
DAS anticipates that the pri m ary use of quizalofop will be to enhance the purity of lines bred with the DAS 40278

- 9 trait. The expected primary use is a s a s e lection agent, to re m ove (kill) any

c or n plants in the seed p r o pagation n u rsery that do not contain the DAS 40 2 78

- 9 trait. It could find more widespread use to control grassy weeds in corn if other herbicide control options prove to be unsatisfactory. E.I. DuPont Co m pany (DuPont) has sub m itted a label a m end m ent (Assure II, EPA Reg. No.352

- 541, active ingredient quizalofop) to pro vide new directions for quizalofop use

as a selection agent in g r ow ing seed corn and as a grass herbi c ide for use in corn.

There are t w o applications considered in predi c ting the use of quizalofop on DAS 40278

- 9 corn: Use as a selection agent in producing hybrid s eed corn, and use as a n herbicide to control glyphosate

- resistant grasses. In the foreseeable future, the latter is not considered likely given the effectiveness of glyphosate in controlling grass weeds. Hence projections are only considered for t he use of quizalofop in seed corn production.

Seed Corn Productio n : The production of hybrid seed corn requires approxi m ately 1 acre of nursery to produce sufficient hy b rid s eed to p l ant 125 acres t h e following season. Two scenarios are presented to bound the range. The first scenario, the lower bound, uses DAS current 5% market share for field and silage corn. The second, upper bound, assumes DAS market share will expand to 45%.

Scenario 1 : 5% m arket share for field and silage corn.

92MM acres /125 acres nursery/acre of field corn x 5% m a r ket share x 0.082 lbs ai/ac/application x 1 application = 3018 lb s quizalofop.

Sc en ario tw o : 45% m arket share for field and silage corn

.
92MM acres /125 acres nursery/a cr e o f fiel d cor n x 45 % m a rk et share x 0.082 lbs ai /ac/application x 1 application = 27,158 lb s quizalofop.

Page 4

- 38Note that if just one percent of the adopters had previously used quizalofop to manage volunteer corn in soybean, either increase will be offset by a corresponding decrease in quizalofop that will

no longer be used to manage corn volunteers. For example if 1% of the soybean growers no longer use quizalofop to control volunteer corn and assuming a 5% market share of DAS

- 40278

- 9 corn is grown in rotation with soybean, the decrease in quizalofop is calcu lated as follows:

76MM acres soybean x 5% market share of DAS

- 40278

- 9 corn adopters x 1% no longer using quizalofop for volunteer control x 0.082 lbs ai/ac/application x 1 application=3116 pounds.

Thus the small increase in quizalofop use that is expected for corn seed production under the Preferred Alternative 2 and 3 is likely to be offset by a corresponding or larger decrease in quizalofop use by soybean growers who had previously used quizalofop to manage corn volunteers. Accordingly, it is expected tha t quizalofop use will decrease overall under the Preferred Alternative and Alternative 3.

G lu f osina t e P r opos e d U se on DA S

- 68416

- 4 Soyb e an
Under the No Action Alternative, glufosinate resistant lines of corn and soybean will still be available (Liberty Link TM ). As noted earlier, the planting of glufosinate resistant soybean increased three fold between 2011

- 2012 and further increases can be anticipated under the No Action Alternative. The Action Alternatives will not impact the availability of glufosinate res istant corn and soybean varieties. In all likelihood, glufosinate and glyphosate resistance traits will be stacked with resistance to 2,4

- D and growers will have the flexibility to use glufosinate, glyphosate, and 2,4

- D as appropriate. Most likely, the use of glufosinate would not increase under the Action Alternatives relative to the No Action Alternative. Possibly, glufosinate use will decrease relative to the No Action Alternative if 2,4

- D is considered a more favorable option for glyphosate resistant w eed control compared to glufosinate.

R e ferences

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. Benbrook, Charles M. 2012. "Impacts of genetically engineered crops on pesticide use in the U.S.

-- the first sixteen years." Environmental Sciences Europe 24.24. http://www.enveurope.com/content/24/1/24

. Burton, J.D., J.W. Gronwald, D.A. Somers, B.G. Gengenbach, and D.L. Wyse. 1989. "Inhibition of corn acetyl

- CoA carboxylase by cyclohexanedione and aryloxyphenoxypropionate herbicides." Pesticide Biochemistry and Physiology 34: 76

- 85. DAS.2012a. "DAS comments to APHIS

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- 0019. Stewardship. Herbicide volume estimate on soybean. off target exposure. trait stacking. 2,4

- D toxicity evaluation. analysis for the presence of dioxins and furans . errata. non ge soybean. regulatory status of herbicides that may be used on enlist soybean, 2,4

- D choline formulation, lack of toxicological or biological synergistic effects between glyphosate and 2,4

- D, auxin resistant waterhemp, impact of enlist on he rbicide use." DAS.2011a. "Economic and Agronomic Impacts of the Introduction of DAS

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- 39Petition for Determination of Nonregulated Status for Herbicide Tolera nt DAS

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- 9 Corn . Ed. Blewett, T. Craig 202. DAS.2012b. "EnlistTM Weed Control System." PowerPoint Slide Deck presented June 11, 2012 to APHIS

- BRS and Louis Berger Inc. staff, . Ed. Blewett, T.C. 68. DAS.2013a. "Information Addressing Questions 1, 2 and 3 from Section A. Herbicide Use Issues." DAS

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- 4 Soybean and DAS

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- 9 Corn, Dow AgroSciences Petition Numbers 09

- 349

- 01p and 09

- 233

- 01p, Supplemental Documentation in Support of Environmental Assessments : . DAS.2011b. "Petition for Determination of N onregulated Status for Herbicide Tolerant DAS

444Ø6

- 6 Soybean." Ed. Mark, S. Krieger: Dow AgroSciences. 228. http://www.aphis.usda.gov/brs/aphisdocs/11_23401p.pdf

. DAS. 2010a. Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

40278

- 9 Corn. Submitted by L. Tagliani, Regulatory Leader, Regulatory Sciences & Government Affairs . Indianapolis, IN: Dow AgroSciences, LLC. DAS.2010b. "Petition for Determination of Non regulated Status for Herbicide Tolerant DAS

68416

- 4 Soybean." Ed. Mark, S. Krieger: Dow AgroSciences. http://www.aphis.usda.gov/biotechnology/not_reg.html

. DAS.2012c. "PowerPoint Presenta tion: EnlistTM Weed Control System." T.C. Blewett, Dow AgroSciences LLC, . 68. DAS.2013b. "Supplemental Documentation in Support of Environmental Assessments in Response to Questions 1

- 3 Received December 12, 2012 regarding DAS

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- 4 s oybean. Herbicide use issues." Ed. Hoffman, Neil. DAS. 2013c. "Supplemental Documentation in Support of Environmental Assessments regarding DAS

- 40278

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- 4 soybean. 2,4

- D weed resistance prevention and management, DAS herbicide formulation , geographic areas where other crops are in close proximity or will be rotated with corn/sybean

". DAS. 2012d. Supplemental Information for Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

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- 9 Corn; Estimate of Herbicide Vol ume and Impact on Environmental Load of Herbicides with the Introduction of Enlist corn (DAS

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. Indianapolis, IN: Dow AgroSciences, LLC. DAS. 2011c. Supplemental Information for Petition for Determination of Nonregulated Status for Herbicide Toleran t DAS

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- 9 Corn; Regulatory Overview of 2,4

- D and Quizalofop Use on DAS

- 40278

- 9 Corn. Submitted by T.C. Blewett, Regulatory Leader, Regulatory Sciences & Government Affairs. Indianapolis, IN: Dow AgroSciences, LLC. DAS.2013d. "Supplementary Documentati on Regarding Herbicide Use and Weed Resistance Management in Support of Environmental Assessments/Environmental Impact Statement." Response to follow up questions sent between Feb 2 and May 3, 2013 regarding DAS

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- 4 soybean. treatm ent acres, flutiacet

methyl, herbicide use plots based on site of action, weed resistance management considerations based on site of action and chemistry family, herbicide use when only one herbicide is used, current 2,4

- D use, grass weeds

. Devine, M.D., a nd A. Shukla. 2000. "Altered target sites as a mechanism of herbicide resistance." Crop Protection 19: 881

- 89. DuPont. 2010. "DuPontTM Assure® II Herbicide Label." 2010. Web. March 31 2011 http://www.cd ms.net/LDat/ld742006.pdf

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- 40Farm Industry News. 2013."Glyphosate

- resistant weed problem extends to more species, more farms." Farm Industry News . Web. September 27, 2013. Foresman, C. 2009. "Syngenta Resistance FighterTM Message Board. Figure 2." 2009. Web. Accessed January 16, 2011 http://blog.syngenta

‐ us.com/blogs/ask_the_expert/archive/2009/04.aspx. Gianessi, L.P., and N. Reigner. 2006. Pesticide Use in U.S. Crop Production: 2002

- with Comparison to 1992 & 1997

- F ungicides & Herbicides . Washington, DC: Crop Life Foundation, Crop Protection Research Institute. Heap, I. 2011. "The International Survey of Herbicide Resistant Weeds." (2011). Web. April 24, 2011 www.weedscience .com

. Industry Task Force II. 2005. "2,4

- D Research Data." 2005. Web. April 4 2011 http://www.24d.org/background/Backgrounder

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- 2005.pdf

. Kelley, K.B., and D .E. Riechers. 2007. "Recent developments in auxin biology and new opportunities for auxinic herbicide research." Pesticide Biochemistry and Physiology 89.1: 1

- 11. Monsanto.2012. "Petition of the Determination of Nonregulated Status for Dicamba

- Tolerant Soy bean MON87708." MON 87708

- 9 . Ed. Monsanto. Missouri: Monsanto. 723. Nice, G., B. Johnson, and T. Bauman. 2013. "A Little Burndown Madness." 2013. Web. August 5, 2013 http: //extension.entm.purdue.edu/pestcrop/2010/issue1/Burndown.pdf

. OSTP. 2001. Case Studies of Environmental Regulation for Biotechnology: Herbicide

- Tolerant Soybean . Washington, DC: The White House Office of Science and Technology Policy. http://www.whitehouse.gov/files/documents/ostp/Issues/ceq_ostp_study4.pdf

. Powles, S.B., and C. Preston. 2009. "Herbicide Cross Resistance and Multiple Resistance in Plants." Herbicide R esistance Action Committee 2009. Web. April 19 2011 http://www.hracglobal.com/Publications/HerbicideCrossResistanceandMultipleResi
st ance/tabid/224/Default.aspx

. Rausch, D.2013. "Differences in herbicide use in corn and soybean." Ed. Hoffman, Neil. Southeast Farm Press. 2012. "Glufosinate herbicide shortage sparks controversy." 2012. Web http://southeastfarmpress.com/cotton/glufosinate

- herbicide

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- sparks

controversy

. Tu, M., C. Hurd, and JM Randall. 2001 Weed Control Methods Handbook: Tools and Techniques for Use in Natural Areas . Ed. Conservancy, The Nature: UC Davis, CA. United States Geological Survey.No Date. "Estimated Annual Agricultural Usage Map for Glyphosate." Pesticide Usage Maps . Ed. National Water

- Quality Assessment Program. http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=02&map= m1099

. US

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- D (030001, 030004)

- Screening Level Usage Analysis (SLUA)." Ed. Office of Chemical Safety and Pollution Preventi on. Washington, D.C.: U.S. Environmental Protection Agency. Vol. 2013. http://www.regulations.gov/#!documentDetail;D=EPA

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- D. Human Health Assessment Scoping Document in Support of Registration Review." Ed. Office of Chemical Safety and Pollution Prevention. Washington, D.C.: U.S. Environmental Protection Agency. 36. Vol. 2013. http://www.regulations.gov/#!documentDetail;D=EPA

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- EPA.2012c. "BEAD Chemical Profile for Registration Review: 2,4

- D." EPA

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2012

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- Registration Review of Quizalofop

- ethyl (128711) and Quizalofop

- p

- ethyl (128709)." Ed. Office of Prevention, Pesticides, and T oxic Substances,. Washington, D.C.: U.S. Environmental Protection Agency. 8 of Docket Number EPA

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- D . Washington: U.S. Environmental Protection Agency. http://www.epa.gov/oppsrrd1/REDs/24d_red.pdf

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- Resistant Weeds by Site of Action." 2013. Web. 12/6/2013.

Page 4

- 42

### Common Weeds in Corn a nd Soybean Appendix 5.

Page 5

- 1Common Weeds in Corn and Soybean

Weeds are simply plants growing in areas where their presence is undesired by humans ( Baucom and Holt 2 009 ) . Plants that colonize frequently disturbed environments have evolved with characteristics or mechanisms that allow them to survive conditions in agricultural environments

. Weedy plants typically exhibit early germination and rapid growth from see dling to sexual maturity, have the ability to reproduce sexually and asexually, and therefore are well adapted to agricultural fields ( Baucom and Holt 2009 )

. The presenc e of weeds in corn and soybean fields is a primary detriment to productivity. Weeds are the most import ant pest complex in agriculture, impacting yields by competing with crops for light, nutrients, and moisture. In addition to taking valuable resources f rom crops, weeds can introduce weed seed or plant material to a crop, thereby reducing the market grade of the crop.

Additionally, w eeds can harbor insects and diseases; weeds also can interfere with harvest, clogging and causing extra wear on harvest eq uipment ( Loux, St achler et al. 2008 ) . For example, s ome winter annuals have been found to serve as alternative hosts for the soybean cyst nematode, a pest that affects soybean yields in the U.S.

Effective weed management involves an understanding of weed biology and of weed management strategies. This section provides an overview of weed types, the weed seed bank, and the timing and occurrence of weeds. Also described are the types of weeds that occur in corn and soybean. Weed management is discussed in Appendix 3.

W eed Classification

Weeds are classified according to their life cycle, as annuals, biennials or perennials. Weeds are also classified as broadleaf (dicots) or grass (monocots). Weeds can reproduce by seed, rhizome (underground creeping stems), or other u nderground part (e.g., buds, bulbs ).

An annual is a plant that completes its lifecycle in one year or season and reproduces only by seed. Annuals can be further differentiated into summer or winter annuals. Summer annuals appear in the spring or early summer and die prior to or by the first frost, producing seeds within the same growing season. These weeds grow rapidly, strongly competing with crops for resources, and can outgrow and shade slower

- growing crops. These weeds tend to be the most problema tic weeds in corn and soybeans, as they share a similar life cycle.

Summer annuals can be further categorized into three groups: small

- seeded summer annual broadleaf weeds, large

- seeded summer annual broadleaf weeds, and summer annual grass weeds ( Schonbeck 2010 ) . Some small

- seeded s ummer annual broadleaf weeds include pigweeds, common lambsquarters, common purslane, galinsoga, and smartweeds. Commonly found large

seeded summer annual broadleaf weeds include velvetleaf, common cocklebur, and morning glory. Summer annual grass weeds have small to medium sized seeds and include foxtail, crabgrass, and goosegrass.

Winter annuals typically emerge in late summer or early fall, but can also germinate as late as early spring. Usually these weeds over

- winter as small seedlings and set seed in the spring.

Page 5

- 2These weeds have little effect on warm season crops. Common winter annuals include purple deadnettle, henbit, field pennycress, shepherd’s

- purse, and chickweed ( Scho nbeck 2010

, Mock, Creech et al. 2011 )

. Biennials have a life cycle of two years or seasons. After persisting as low

- growing vegetation during their first season, biennial weeds overwinter, then flower an d produce seeds in their second growing season. Examples of biennial weeds are burdock, bull thistle, poison hemlock, and wild carrot.

Perennials are plants that live for more than two years and are typically categorized as simple or creeping or invasive perennials. T hese weed species have root systems that store large amounts of food reserves, making them difficult to control. Winter perennials are particularly competitive and difficult to control because these weeds re

- grow every year from rhizomes or r oot systems ( DAS 2010 )

. Canada thistle, bermudagrass, common milkweed, common pokeweed, dandelion, johnsongrass are examples of perennial weeds ( Penn State University 2009

, Mock, Creech et al. 2011 )

. Generally, annual grass and broadleaf weeds are considered the most common weed pro blems in corn and soybean ( Krausz, Young et al. 2001

, DAS 2010 )

.
Weed Seed Bank

An important concept in weed control is the seed bank which is the reservoir of seeds that are on the soil surfac e and scattered at different depths in the soil. The soil weed seedbank determines the size and species composition of the weed community within a growing season ( Norsworthy 2012 )

. Under favorable conditions, these seeds have the potential to germinate and emerge, creating weed pressure (i.e., competition) in crops. The weed seed bank contains recently dropped seeds, older seeds mixed into the soil, tubers, bulbs, rhizomes, and othe r vegetative structures. Climate, soil characteristics, shifts in agricultural management practices, such as tillage, crop selection, and weed management practices, affect the density and species composition of the seed bank within a given field ( Davis, Renner et al. 2005

, May and Wilson 2006
, Buhler, Hartzler et al. 2008 )

. The majority of seeds in the weed seed bank come from the weeds that have grown and set seed in the field. Wind, water, animals, and birds can carry se eds, adding to the weed seeds already present. Also, manure or other material (e.g., mulch, feed, soil) transported by humans or farm equipment from other locations can be indirect sources of weed seed ( Renner 2000 )

. Agricultural soils ca n contain thousands of weed seeds and a dozen or more vegetative weed propagules per square foot ( Menalled and Schonbeck 2013 )

. Estimates of weed seeds in Corn Belt soils range from 56 to 14,864 seeds per square foot ( Renner 2000 ) . Annual weeds produce large numbers of seeds. For example, a pigweed plant can shed at least 100,000 mature seeds and one lambsquar ters plant can produce more than 50,000 seeds ( Renner 2000 )

. If left untended and without crop competition, giant ragweed can produce approximately 10,000 seeds, common waterhemp 70,000 seeds, and waterhemp 100,000 seeds, or more, per pla nt. L arger

seeded broadleaf weeds are not as prolific in comparison to small

- seeded summer broadleaf weeds, but seed production is still high, with a few hundred to a few thousand per plant

Page 5

- 3( Schonbeck 2010 ) . It has been observed that weeds in agricultural fields produce less seeds as a result of competition from the crop, damage from herbicides, and other factors, although these weed still produce high numbers of seeds that can affect production ( Buhler, Hartzler et al. 1997 )

. Although s eedbanks are made up of numerous weed species, generally only a few species will comprise 70 to 90 percent of the total seed bank ( Wilson 1988

, Buhler, Hartzler et al. 1997

, Renner 2000 ) . For example, common lambsquarters (Chenopodium album) is the dominant weed seed in many field soils in the north central region of the U.S. (Michig an) ( Renner 2000 )

. A second smaller group of weed species may represent 10 to 20 percent of the seed bank ( Buhler, Hartzler et al. 1997 )

. Additionally, only a fraction of th e seeds in a weed seed bank germinate and grow each year. Birds, rodents, insects, and other animals typically will consume available weed seeds found on the soil surface. Some seeds may decay or become un viable in the soil; other seeds may germinate but will die. Some seeds can remain dormant in the soil for long periods of time. When changes in the cropping system change, creating conditions that are suitable for germination and development of a particular weed species, that species can respond rapidl y, becoming non

- dormant and establish itself in the cropping system ( Renner 2000
, Durgan and Gunsolus 2003

, May and Wilson 2006

, Steckel, Sprague et al. 2007 )

. It is estimated that less than 10% of the weed seeds in the soil are non

- dormant and able to germinate w ithin a season. The remaining dormant seeds thereby serve to extend the longevity of the seed bank ( Renner 2000
, PhysicalWeed ing 2009 )

. For example, s ummer annuals can remain viable for years, even if buried deeper in the soil, while the larger broadleaf seeds can remain viable for decades ( Schonbeck 2010 )

. The majority of weeds grow from seeds in the top two inches of soil with the most significant numb ers emerging from only the top one inch of soil ( PhysicalWeeding 2009 )

. In general, most small

- seeded weeds (e.g., foxtail, pigweed) germinate and emerge within the upper half inch of the soil surface. The large

- seeded summer annual broadleaf weeds are usually found in soils below the surface layer (about 0.5 to 2 inches belo w the surface) and can germinate from soil depths of 1.5 inches or more. Summer annual grass weeds germinate predominantly from the top inch of soil. Generally, tillage brings these seeds to the surface, where they rapidly grow in response to light . The effects of different forms of tillage on the prevalence of weed species are discussed further, below.

Weed populations change in response to agricultural management decisions. Collectively, management decisions will impart selection pressures 1 on the present weed community, resulting in weed shifts on a local level (i.e., field level). These weed shifts occur regardless of what the selection pressure may be and may result in changes in weed density or weed diversity ( Reddy

1 Selection pressure may be defined as any event or activity that reduces the reproductive likelihood of an individual in proportion to the rest of the population of that one individual. In agriculture, selection pressure may be imparted by any facet of ma nagement in the production of a crop, including the type of crop cultivated, strategy of pest management, or when and how a crop is planted or harvested.

Page 5

- 4and Norsworthy 2010

, Weller, Owen et al. 2010 ) . Weed shifts are generally most dramatic when a single or small group of weeds increases in abundance at the expense of other weed populations, potentially dictating the primary management efforts of the grower.

T h e vertical distribution of weed seeds in the soil is primarily influenced by the tillage system used. 2 These resulting changes in the distribution of the weed seeds in the weed seedbank will impact weed emergence and the resulting weed population in farm fields ( Renner 2000 ) . As shown in Figure 5

- 1, the practice of no

- till results in a majority of the weed seeds remaining at or near the soil surface where they have been deposited ( Renner 2000
, Shrestha, Lanini et al. 2006

, Menalled and Schonbeck 2013 ) . In no

- till field s with more seeds at the surface, a greater diversity of annual and perennial weeds species may occur ( Baucom and Holt 2009 ) . Winter annuals thrive in soil that is undis turbed from late summer or fall through early summer the following year which is best provided by no

- till systems. Similarly, biennial weeds are prevalent in fields that have been no

- till for several years, as they need undisturbed soil for two consecutiv e growing seasons.

Under reduced tillage systems (such as chisel plowing), approximately 80 to 90 percent of the weed seeds are distributed in the top four inches, with the majority found at depths ranging from two to four inches. Summer annual grass weeds germinate predominantly from the top inch of soil with prevalence in shallow and reduced tilled fields ( Curran, Lingenfelter et al. 2009 ) . With recent increased rates of conservation tillage, there has been an observed decrease in large

seeded broadleaf weeds and an increase in perennial, biennial, and shallow

- emerging annual grasses, small

- seeded broadleaves, and winter annual weed species in those fields ( Green and Martin 1996

, Durgan and Gunsolus 2 003
, Norsworthy 2012 ) . The growth and spread of some perennial species that reproduce by spread of underground structures (e.g., rhizomes) may be encouraged by no

- till or conservation tillage system which allows these st ructures to remain undisturbed ( Buhler, Hartzler et al. 2008

, Baucom and Holt 2009

, Curran, Lingenfelter et al. 2009 )

.

2 Tillage represents a mechanical means of weed control and is generally characterized by the amount of remaining in

- field residue and may be classified as conservation ( > 30 percent), reduced (15

- 30 percent), or intensive (0

- 15 percent) CTIC (2008). 2008 Amendment to the National Crop Residue Management Survey Summary, Conservation Technology Information Center.

Page 5

- 5Figure 5

- 1

. Vertical Distribution of Weed Seeds in the Soil Profile at Depths of 0 to 2 inches, 2 to 4 inches, and 4 to 6 inches Affected by Different Tillage Regimes Source: ( Shrestha, Lanini et al. 2006 )

W e ed seeds become buried approximately four to six inches below the surface as a result of increasing tillage ( Menalled and Schonbeck 2013 )

. As fewer weeds can germinate when buried, weed diversity tends to decline and annual large

- seeded broadleaves are more prominent ( Norsworthy 2012 )

.
These shifts in weed species necessitat e changes in weed management strategies. Tillage practices must be regularly changed, in a manner similar to that of other agricultural production practices, to prevent buildup of any particular species or group of weeds in the soil seedbank.

Weed Emergence/Timing

In addition to weed density, the timing of weed emergence affects how they compete with the corn or soybean crop and influences the level of crop yield loss. The critical period of weed control (CPWC) is the time during which weeds must be controlled to prevent yields losses. The key components defining CPWC are 1) knowing when weeds need to be removed and 2) when the crop becom es dominant ( Boerboom 2000 )

. Weeds emerging before the CPWC may not impact crop yields if those weeds are controlled by the start of the CPWC

. Weed competition occurring after the end of the CPWC will not affect yield ( Boerboom 2000

, Knezevic 2007 ) . In particular, e arly in the growing season, the critical period of weed competition is most affected by: 1) how competitive the different weed species are, 2) the density of weeds, and 3 ) the relative time of weed emergence ( Boerboom 2000 )

. Corn is more vulnerable to early competition by weeds than soybean, especially when weed density is high, when corn is under stress from environmental conditions (e.g., drought, extreme 90%

27%
12% 9%

66%

25% 1% 7%

63%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

No-till Chisel Plow Moldboard PlowPercent Seeds (%)

Tillage System 4-6

2-4

0-2 Soil Depth

(in)

Page 5

- 6wet conditions, cold soils), or when the crop is slow to establish ( Monsanto 2012 )

. W eed control is most critical during the first three to five weeks after emergence of corn seedlings ( Sikkema and Hamill 2005

, ANR 2009 )

. Weed costs in corn begin almost as soon as the corn emerges. Weeds that are about 3 to 4 inches tall when corn is at the V

- 3 to V

- 4 growth stage 3 are going to present the most competition . If the weeds are taller than corn, they will shade the crop. Control should be begin four to five days (one to two leaves) prior to the beginning o f the CPWC ( Knezevic 2007 ) . If weeds are controlled early, after several weeks when the corn canopy closes, corn can compete with later emerging weeds by shading them out. Narrow row spacing and adequate plant populations promote early corn canopy closure ( Rosenberg 2013 )

. Although weeds do not impact corn yield nearly as much later in the corn growing season, those weeds can harbor destructive ins ect pests , such as thrips, which can carry Fusarium ear rot, and armyworms, which can defoliate corn. Additionally, w eeds in corn can also reduce silage and feed quality, slow harvesters by causing wheel slippage or clogging, raise grain moisture content, and reduce future corn harvests by add ing to the seed bank ( ANR 2009 )

. In soybean, t he later that weeds emerge, the less i mpact they will have on yield, although weeds emerging later can have a negative influence on seed quality and harvest efficiency ( Prostko 2013 )

. S oybean plants withstand early season weed competition longer than corn because the soybean canopy closes earlier ( Boerboom 2000 ) . The extent of canopy closure restricts the light available for weeds and other plants growing below the soybean. In addition, canopy closure occurs more quickly when soy bean is drilled or planted in narrow rows ( Boerboom 2000

, Bradley 2006 ) ; however, in some studies it has also been observed that, depending on factors such as weed species, environmental conditions (i.e., rainfall amounts) and soybean cultivar, soybeans are able to compete with weeds with no result ing yield reduction ( Krausz, Young et al. 2001 ) . Place et al. have determined that larger soybean seeds produce a larger canopy more quickly and are, therefore, more successful at outcompeti ng weeds ( Place , Reberg

- Horton et al. 2011 )

. Full

season soybean planting is preferable during the drier late spring conditions; however, summer annual weed emergence often occurs at this same time, resulting in a high level of weed interference with soybean emergen ce and establishment ( DeVore, Norswo rthy et al. 2013 )

. Common Weeds in Corn and Soybean

To assist growers in managing weeds, individual states, typically through their state agricultural extension service, list the prevalent weeds in crops in their area and the most effective means for th eir control (see, e.g., IPM 2004
, IPM 2007
, University of California 2009 )

. Some of the key weed species found in corn and soybean fields are described in the following sections.

Weed species emerge in a particular order throughout the year with each species having one or more periods of high emergence. The initial emergence date can vary fr om year to year, but the order stays relatively constant. Figure 5

- 2 shows the relative emergence of common weed species found in summer annual crops such as corn and soybean. Weed emergence timing can dictate which weeds will be the most problematic for or be more easily controlled by a specific

3 Corn at the V3 is approximately 2 weeks after emergence and is ~8 inches tall and at the V4 growth stage is near or at 12 inches tall.

Page 5

- 7crop production or weed management practice ( Buhler, Hartzler et al. 2008 ) . Weed management is discussed in Appendix 3.

Figure 5

- 2

. Re lative Emergence of Common Weeds of Summer Annual Crops

. Source: ( Buhler, Hartzler et al. 2008 )

. Problem Weeds in Corn and Soybean

Based on a survey of growers in 2011, Table 5

- 1 lists the 10 broadleaf or grass weeds found in corn and soybean that growers indicated they most often had to manage in their fields ( DAS 2013 ) . The first column lists those weeds on a national basis and the remaining columns list the weeds that are most problematic in each region. Regions that produce very little corn or soybean

w ere not included. The Southeast region produces very little corn, but significant amounts of soybean; so information for the region was included for soybean but not for corn. Likewise the Prairie Gateway produces considerable corn but little soybean and wa s included in the section for corn but not soybean. Many of the problem weeds are present in multiple regions.

Page 5

- 8Table 5

- 1

. National and Regional List of Top Ten Troublesome Broadleaf and Grass Weeds in Corn and Soybean in 2011.

Source: ( DAS 2013 )

Based on the information in Tab le 5

- 1, a list of the unique problem weeds in corn and soybean are presented in Table 5

- 2. In some cases the same weed species are listed under two different common names in Table 5

- 1. In Table 5

- 2, common waterhemp and tall waterhemp are listed as
water hemp. Marestail and horseweed are listed as horseweed. Moringglory and field bindweed are listed as field bindweed. Thistle is listed as Canada, Russian, or Musk thistle. Foxtail is listed as giant, yellow, or green foxtail. US Corn Heartland Northern Crescent Northern Great Plains Prairie Gateway Broadleaf Weeds most treated for
VELVETLEAF VELVETLEAF LAMBSQUARTERS VELVETLEAF PIGWEED, REDROOT PIGWEED, REDROOT WATERHEMP, COMMON PIGWEED, REDROOT PIGWEED, REDROOT KOCHIA LAMBSQUARTERS LAMBSQUARTERS VELVETLEAF WATERHEMP, COMMON THISTLE WATERHEMP, COMMON RAGWEED, GIANT RAGWEED SUNFLOWER VELVETLEAF
COCKLEBUR COCKLEBUR RAGWEED, GIANT COCKLEBUR MORNINGGLORY RAGWEED, GIANT PIGWEED, REDROOT DANDELION KOCHIA THISTLE, RUSSIAN
KOCHIA RAGWEED THISTLE, CANADA LAMBSQUARTERS BINDWEED, FIELD
MARESTAIL MARESTAIL MORNINGGLORY MARESTAIL COCKLEBUR
RAGWEED MORNINGGLORY COCKLEBUR THISTLE, CANADA THISTLE, MUSK
MORNINGGLORY HORSEWEED THISTLE SUNFLOWER SUNFLOWER Grass weeds most treated for
FOXTAIL FOXTAIL FOXTAIL FOXTAIL, YELLOW JOHNSONGRASS FOXTAIL, GIANT FOXTAIL, GIANT QUACKGRASS FOXTAIL SANDBUR FOXTAIL, YELLOW FOXTAIL, YELLOW FOXTAIL, GIANT FOXTAIL, GREEN WHEAT, VOLUNTEER FOXTAIL, GREEN FOXTAIL, GREEN FOXTAIL, YELLOW FOXTAIL, GIANT PANICUM, TEXAS
JOHNSONGRASS JOHNSONGRASS CRABGRASS SANDBUR BARNYARDGRASS
CRABGRASS PANICUM, FALL FOXTAIL, GREEN WHEAT, VOLUNTEER SICKLEGRASS WHEAT, VOLUNTEER CUPGRASS, WOOLLY PANICUM, FALL OAT, WILD QUACKGRASS BARNYARDGRASS GRASSES, ALL BARNYARDGRASS PANICUM, FALL QUACKGRASS MILLET, WILD-PROSO CHEAT
BARNYARDGRASS CRABGRASS CUPGRASS, WOOLLY CRABGRASS

US Soybeans Heartland Northern Crescent Northern Great Plains SouthEast Broadleaf Weeds most treated for
REDROOT PIGWEED WATERHEMP, COMMON LAMBSQUARTERS VELVETLEAF PIGWEED, REDROOT
COMMON WATERHEMP VELVETLEAF VELVETLEAF WATERHEMP, COMMON MORNINGGLORY
VELVETLEAF RAGWEED, GIANT PIGWEED, REDROOT COCKLEBUR MARESTAIL
COCKLEBUR LAMBSQUARTERS RAGWEED MARESTAIL COCKLEBUR
MARESTAIL COCKLEBUR RAGWEED, GIANT PIGWEED, REDROOT AMARANTH, PALMER'S LAMBSQUARTERS PIGWEED, REDROOT DANDELION MUSTARD, WILD SICKLEPOD
GIANT RAGWEED MARESTAIL NIGHTSHADE, BLACK BUCKWHEAT, WILD SIDA, PRICKLY
MORNINGGLORY RAGWEED CHICKWEED, MOUSEEAR LAMBSQUARTERS LAMBSQUARTERS
RAGWEED MORNINGGLORY MORNINGGLORY SUNFLOWER SESBANIA, HEMP
SUNFLOWER WATERHEMP, TALL WATERHEMP, COMMON KOCHIA HENBIT Grass weeds most treated for
FOXTAIL FOXTAIL FOXTAIL FOXTAIL JOHNSONGRASS FOXTAIL, GIANT FOXTAIL, GIANT QUACKGRASS FOXTAIL, YELLOW BARNYARDGRASS
JOHNSONGRASS FOXTAIL, YELLOW FOXTAIL, GIANT OAT, WILD CRABGRASS FOXTAIL, YELLOW JOHNSONGRASS FOXTAIL, YELLOW FOXTAIL, GIANT SIGNALGRASS, BROADLEAF
BARNYARDGRASS CORN, VOLUNTEER CORN, VOLUNTEER FOXTAIL, GREEN RYEGRASS FOXTAIL, GREEN FOXTAIL, GREEN CRABGRASS BROME, DOWNY WATERGRASS
CRABGRASS QUACKGRASS FOXTAIL, GREEN BROME, JAPANESE BLUEGRASS, ANNUAL

Page 5

- 9In summary, there are 25 broad leaf and 22 grass weed species noted from the top ten lists, respectively, that required control measures in the major growing regions of soybean and corn. Some species such as redroot pigweed were problematic in all regions in both corn and soybean fields (marked in green in Table 5

- 2). Other species such as sicklepod, prickly sida, and wild buckwheat were more regional problems. Combining the lists of corn and soybean, there are a total of thirteen broadleaf and nine grass weeds, respectively, that are a problem in both corn and soybean, four broadleaf and seven grass weeds that are mostly problematic in corn (marked in yellow in Table 5

- 2), and eight broadleaf and six grass weeds that are mostly problematic in soybean (marked in blue in Table 5

- 2).

Tabl e 5

- 2

. Summary of Problem Weeds Affecting Corn and Soybean. Broadleaf Weeds Grass Weeds Corn + Soybean Corn Soybean Corn + Soybean Corn Soybean
redroot pigweed henbit wild mustard giant foxtail woolly cupgrass downy brome

lambsquarters Pennsylvania smartweed black nightshade yellow foxtail wild

- proso millet Japanese brome

waterhemp Russian thistle mousear chickweed green foxtail sandbur broadleaf signalgrass

cocklebur musk thistle hemp sesbania johnsongrass fall panicum ryegrass giant ragweed palmer's amaranth crabgrass cheat watergrass

kochia sicklepod wheat, volunteer Texas panicum annual bluegrass

horseweed prickly sida quackgrass sicklegrass
common ragweed wild buckwheat barnyardgrass

field bindweed wild oat

sunflower

Canada thistle

velvetleaf

dandelion
Based on the data in Table 3

- 1 ( DAS 2013 )

. Notes: Green: Weeds managed in both corn and soybean Yellow: Weeds primarily managed in corn Blue: Weeds primarily managed in soybean

References:

ANR, U. (2009) Integrated Weed Management. UC IPM Pest Management Guidelines: Corn

Baucom, R. and J. Holt (2009). "Weeds of agricultural importance: Bridging the gap between evolutionary ecology and crop and weed science." New Phytologist (184): 741

- 743.

Boerboom, C. (2000) Timing Postemergence Herbicide s in Corn and Soybeans. 2011

,

Page 5

- 10Boerboom, C. (2000). "Timing Postemergence Herbicides in Corn and Soybeans." Wisconsin Crop Management Conference 2000 Proceedings Papers

.

Bradley, K. W. (2006). "A Review of the Effects of Row Spacing on Weed Management in Corn and Soybean."

Buhler, D. D., R. G. Hartzler, et al. (1997). "Implications of Weed Seedbank Dynamics to Weed Management." Weed Science 45 (3): 329

- 336.

The species composition and density of weed seed in the soil vary greatly and are closely link ed to the cropping history of the land. Altering tillage practices changes weed seed depth in the soil, which plays a role in weed species shifts and affects efficacy of control practices. Crop rotation and weed control practices also affect the weed seedb ank. Information on the influence of cropping practices on the weed seedbank should be a useful tool for integrated weed management. Decision aid models use information on the weed seedbank to estimate weed populations, crop yield loss, and recommend weed control tactics. Understanding the light requirements of weed seed may provide new approaches to weed management. Improving and applying our understanding of weed seedbank dynamics is essential to developing improved weed management systems. The principles of plant ecology must be integrated with the science of weed management to develop strategies that take advantage of basic plant responses in weed management systems for agronomic crops.

Buhler, D. D., R. G. Hartzler, et al. (2008) Relative emergence seq uence for weeds of corn and soybeans. Sustainable Agriculture 4

CTIC (2008). 2008 Amendment to the National Crop Residue Management Survey Summary, Conservation Technology Information Center.

Curran, W. S., D. D. Lingenfelter, et al. (2009) An Introdu ction to Weed Management for Conservation Tillage Systems

- Conservation Tillage Series Number Two.

DAS (2010). Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

68416

- 4 Soybean. S. K. Mark, Dow AgroSciences.

Page 5

- 11DAS (2013). Su pplementary Documentation in Support of Draft Environmental Assessment

- Responses to Questions 4, 6 and 7 from Section B. 2,4

- D Use. DAS

- 686

- 416

- 4 Soybean and DAS

- 40278

- 9, Corn Dow AgroSciences Petition Numbers 09

- 349

- 01p and 09

- 233

- 01p, , Dow AgroSciences LLC : 33.

Davis, A. S., K. A. Renner, et al. (2005). "Weed seedbank and community shifts in a long

- term cropping systems experiment." Weed Science 53 (3): 296

- 306.

DeVore, J. D., J. K. Norsworthy, et al. (2013). "Influence of Deep Tillage, a Rye Cover Crop, and Various Soybean Production Systems on Palmer Amaranth Emergence in Soybean." Weed Technology 27 (2): 263

- 270.

Durgan, B. R. and J. L. Gunsolus (2003) Develop ing Weed Management Strategies that Address Weed Species Shifts and Herbicide Resistant Weeds. 2011

,

Green, J. D. and J. R. Martin (1996) Dealing with Perennial Broadleaf Weeds in Conservation Tillage Systems. 2011

,

IPM (2004). Crop Profile for Field Corn in Pennsylvania. University Park, PA, Department of Agronomy, Penn State University : 21.

IPM (2007). Crop Profile for Corn in the Northern and Central Plains (KS, NE, ND, and SD), : 26.

Knezevic, S. (2007) Timing Weed Control in Corn to Get t he Most Effect. CropWatch

Krausz, R. F., B. G. Young, et al. (2001). "Influence of weed competition and herbicides on glyphosate

- resistant soybean ( Glycine max )." Weed Technology 15 : 530

- 534.

Loux, M., J. Stachler, et al. (2008). Weed Control Guide f or Ohio Field Crops Ohio State University Extension.

Page 5

- 12May, M. and R. Wilson (2006). Chapter 14: Weeds and Weed Control. Pgs. 359

– 386. Sugar Beet . A. P. Draycott. Oxford, United Kingdom, Blackwell Publishing Ltd. World Agricultural Series: 474 pgs.

Menal led, F. and M. Schonbeck (2013) Manage the Weed Seed Bank

— Minimize "Deposits" and Maximize "Withdrawals".

Mock, V. A., E. J. Creech, et al. (2011). Winter Annual Weeds and Soybean Cyst Nematode Management With a Guide for Identifying Known Weed Hosts, Purdue Extension. WS

- 36

.

Monsanto (2012). "Early

- Season Weed Competition in Corn."

Norsworthy, J. K., Ward, S. M., Shaw, D. R., Llewellyn, R. S., Nichols, R. L., Webster, T. M., Bradley, K. W., Frisvold, G., Powles, S. B., Burgos, N. R., Witt, W. W., and Barrett, M. (2012). "Reducing the Risks of Herbicide Resistance: Best Management Pra ctices and Recommendations." Weed Science (Special issue): 31

- 62.

Penn State University (2009). "An Introduction to Weed Management for Conservation Tillage Systems."

PhysicalWeeding (2009). "Information: Integrated Weed Management." from http://physicalweeding.com/information/index.html

.

Place, G. T., S. C. Reberg

- Horton, et al. (2011). "Effects of soybean seed size on weed competition." Agronomy Journal 103 : 175

- 181.

Prostko (2013) Soybeans Weed Control 2013 Georgia Soybean Production Guide

Reddy, K. and J. Norsworthy (2010). Glyphosate

- Resistant Crop Production Systems: Impact on Weed Species Shifts. Glyphosate Resistance in Crops and Weeds . Hoboken, NJ, John Wile y & Sons, Inc. : 213

- 233.

Renner, K. A. (2000) Weed Seedbank Dynamics. 4

Page 5

- 13Rosenberg, M. (2013). "Effect Of Weed Competition On Corn ".

Schonbeck, M. (2010). Know the Weeds, eXtension.com.

Shrestha, A., T. Lanini, et al. (2006). Conservation Tillage and Weed Management. Agriculture and Natural Sciences . University of California. 8200: 14.

Sikkema, P. H. and A. S. Hamill (2005). "Weed Costs Per Day: New Perspectives on Research into Early Weed Control."

Steckel, L. E., C. L. Sprague, et al. (2007). "Tillage, Cropping System, and Soil Depth Effects on Common Waterhemp (Amaranthus rudis) Seed

- Bank Persistence." Weed Science 55 (3): 235

- 239.

University of California (2009). UC IPM Pest Management Guidelines: Corn. Oakland, CA, University of Californi a Agriculture and Natural Resources, UC Statewide Integrated Pest Management Program : 42.

Weller, S., M. Owen, et al. (2010). Managing Glyphosate

- resistant Weeds and Populations Shifts in Midwestern U.S. Cropping Systems. Glyphosate Resistance in Crops a nd Weeds . Hoboken, NJ, John Wiley & Sons, Inc. : 213

- 233.

Wilson, R., Ed. (1988). Biology of weed seeds in the soil . Weed Management in Agroecosystems: Ecological Approaches. Boca Raton, FL, CRC Press.

Page 5

- 14

### Herbicide Resistance Appendix 6.

Page 6

- 1Herbicide Resistance

Not unlike other agronomic practices, herbicide use may impart selection pressures on weed communities

, resulting in shifts in the weed community that favor those weeds that do not respond to the herbicide used ( Owen, 2008 )

. Herbicide resistance is described by the Weed Science Society of America as the “inhe rited ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type” ( WSSA, 2011b )

. The shift to herbicide resistance in plants is largely a function of the natural selection of herbicide

resistant t raits and is strongly related to the repeated use of one or a limited number of herbicides ( Durgan and Gunsolus, 2003 ; Duke, 20 05 )

. Individual plants within a s pecies can exhibit different responses to the same herbicide rate. Initially, herbicide rates are set to work effectively on the majority of the weed population under normal growing conditions. Genetic variability, inc luding herbicide resistance, is exhibited naturally in normal weed populations, although at very low frequencies. When only one herbicide is used year after year as the primary means of weed control , the number of weeds resistant to that herbicide compare d to those susceptible to the herbicide may change as the surviving resistant weeds reproduce. With no change in weed control strategies, in time, the weed population may be composed o f more and more resistant weeds.

Both the increased selection pressure from the extensive use of glyphosate associated with glyphosate

- tolerant crops along with the subsequent reduction in the use of other herbicides and changes in weed management practices (i.e., conservation tillage or no

- till) have resulted in weed populat ion shifts and increasing glyphosate resistance among some weed populations ( Owen, 2008 ; Duke and Powles, 2009 ) . G lyphosate

- resistant crops themselves do not influence weeds any more than non

- transgenic crops. It is the weed control tactics chosen by growers that create selection pressure that ultimately over time change s these weed communities and may result in the selection of herbicide

- resistant weeds ( Owen, 2008 )

. History of W eed R esistance to H erbicides and its D evelopment

One of the earl iest selective chemical herbicides to be used in agriculture was 2,4

- D, a synthetic auxin, whose commercial use began in 1945 ( Burnisde, 1996 ) . Use of 2,4

- D in corn was successful in controlling broadleaf weeds such that in the mid

- 1950s 2,4

- D was applied to nearly

one

- half of all U.S. corn acres ( Knake, 1996 ) . Within 12 years, the first herbicide resistance to 2,4

- D was reported in spreading dayflower in a Hawaiian sugarcan e field ( Commelina diffusa ) in 1957 (see report in ( Sellers et al. , 2011 ; Isaac et al. , 2013 ) ) and then in field bindweed ( Convolvulus arvensis) in Kan sas cropland in 1964 ( Heap, 2013a )

. Simazine was the first triazine to be used commercially in 1956. In 1958, the herbicide atrazine was first registered for weed cont rol in corn in the U.S. Similar to what had occurred with 2,4

- D, triazines were used extensively in the 1960s and common groundsel resistant to triazine herbicides was discovered in Washington in 1970 ( Buhler, unknown ) . Regardless of the occurrence of resistant weeds, atrazine was, and still is, an extremely effective herbicide due to it s broad spectrum, low cos t, and flexible timing of applications ( International, 2012 )

.

Page 6

- 2ALS inhibitors or Group 2 herbicides were introduced in the mid

- 1980s a nd became extensively used in both corn and soybeans. With its broad

- spectrum weed control, residual activity, and flexibility in application timing, the Group 2 herbicides became popular in the late 1980s and early 1990s. For example, by the early

- 1990s , Pursuit TM , containing the ALS herbicide imazethapyr, was used on more than 75 percent of the soybeans in Iowa ( Tranel and Wright, 2002 ) . The widespread use of Group 2 herbicides resulted in the rapid selection of ALS

- resistant waterhemp. By the mid

- 1990s
, Group 2 resistant waterhemp was so widespread that the industry essentially stopped recommending Group 2 herbicides for this weed ( Hartzler, 2013 )

. Sales of glyphosate began in 1974 and it became one of the most commercially successful and dominant herbicides in the U.S. ( Duke and Powles, 2008 )

. There are several reasons for the success of glyphosate in the market and the corresponding market sector penetration of glyphosate

- tolerant crops since the ir introduction in the mid

- late 1990s. Glyphosate: 1) works

non

- selectively on a wide range of plant species; 2) is a relatively low

- cost herbicide ; 3) enhances no

- till farming practices ; and 4) has minimal animal toxico logical and environmental impact ( Owen, 2008 ; Duke and Po wles, 2009 ) ( Duke and Powles, 2008 )

. The widespread adoption of glyphosate

- tolerant soybean, in combination with an increased

r eliance on glyphosate, has been related to the adoption of no

- till cultivation which depends on controlling weeds without tillage. Glyphosate tolerant soybean also led to a simplification in weed control compared to past practices, reduced input and labor costs associated with the cultivar and glyphosate use, and increased flexibility in herbicide application timing ( Lorenz et al. , 2006 )

. Most instructive are the events leading to the development of glyphosate resistance in weeds in the U

. S. The p revious history of glyphosate use for 20 years did not result I the selection of herbicide resistant weeds. As a result, industry promoted the view that widespread glyphosate

use was unlikely to result in the selection of glyphosate resistant weed s ( Bradshaw et al. , 1997 )
, despite the fact that resistance to other herbicides

, such as 2,4

- D were being reported (see history in ( Mithila et al. , 2011 )

. The first case r eported, glyphosate resistant rigid ryegrass, was documented and confirmed in Australia in 1996 ( Powles et al. , 1998 ) , over twenty years after glyphosate first began to be used in agriculture.

Herbicide

- resistant crops were intr oduced in 1996 with glyphosate

- resistant soybean rapidly adopted by growers

. As glyphosate went off patent in 2000, increased usage of glyphosate

resistant crops was facilitated by the low price of the herbicide. T ank mixes for separate activity against grasses and broad

- leaf weeds were not needed when glyphosate could be used for weed control . In the mid

- 1990s, 51% of growers were using three, four or more herbicides for soybean weed control (cited in Gianessi et al. ( 2008 ) ) or about three overall in 1995 ( USDA

ERS, 1997 )

. W ith the availability of glyphosate and glyphosate

- resistant crops , herbicide applications could be reduced in many situations.

The efficacy of post

- application s of glyphosate became clear, with weed cont rol often not requir ing a pre

- application for good control ( Reddy, 2001 ) . If a grower needed additional weed control for effectiveness or flexibility, a pre

- application of glyphosate and a post

- glyphosate
app lication w ere as effective and cost less than a pre

- application with a non

- glyphosate residual herbicide followed by post

- application of glyphosate ( Reddy, 2001 ) . I ncreasing glyphosate

Page 6

- 3application s resulted i n a decline of the sale s and use of most other herbicides. The earliest U

. S

. glyphosate resistance in a GE crop was found in horseweed, Conyza c anadensis , in Delaware soybean in 2000 ( Heap, 2013a ) . Increasing exposure of weeds to glyphosate in other herbicide resistant crops such as corn and cotton soon began to expand the numbers and populations of resistant weeds in the U

. S.

The intense use of glyphosate compared to sparing use of other herbicides on field crops is apparent in overall herbicide use trends over the last decade, and surveys of grower usage

, such as that of Prince et al. ( 2012 ) , provide specific details (see also Figures 4

- 1, 4

- 3. 4

- 4, and 4

- 5). These surveys give evidence of the prevalent practices employed by growers in which glyphosate was nearly the only herbicide used with the subsequent overexposure of crops and weeds to glyphosate. In 2005, surveyed growers in multiple states rotating soybean and corn indicated they chose glyphosate 22% of the time for spring burndown, versus 9% for other herbicides (Table 6

- 1). For continuous soybean, growers chose glyphosate 46% of the time and 22% another herbicide (Table 6

- 1) ( Prince et al. , 2012 ) . Overall, 74% of the continuous soybean growers used glyphosate two or more times during a growing season (Table 6

- 2), and growers rotating between corn and soybean, used glyphosate two or more times 50% of the time on soybean. When growers used non

- glyphosate herbicides, continuous soybean growers used these herbicides in post

- emergence applications 67% of the time, and corn/soybean growers applied the herbicides on soybean post

- emerge nce 35% of the time (Table 6

- 2). Growers were choosing glyphosate frequently for pre

- plant burndown, but also post

- planting with high frequency, so that repeated exposure of weeds to glyphosate during crop production was common within the same season, and because the most common rotation crop for corn is soybean, exposure of weeds to selecting doses of glyphosate occurs in consecutive seasons. Prince et al. ( 2012 ) document that in 2005, glyphosate tolerant corn/glyphosate tolerant soybean rotations, only 9% of soybean acreage received non

- glyphosate herbicides, although 45% of corn acreage received non

- glyphosate treatment.

Table 6

- 1

. Frequency of Spring Pre

- plant Application of Glyphosat e among Surveyed Growers (2005) Herbicide Application Crop Glyphosate Non

- glyphosate Continuous soybean 46% 22% Soybean in soybean/corn rotation 22% 9%

Source: ( Prince et al. , 2012 )

T able 6

- 2

. Frequency of Glyphosate Application to Crop by Surveyed Growers (2005). Herbicide Application Crop Glyphosate Non

- glyphosate Frequency 1X 2X 3X 1X 2X 3X Continuous soybean 23 62 12 27 7 67
Soybean in s oybean/corn rotation 48 47 3 53 12 35
Source: ( Prince et al. , 2012 )

Page 6

- 4It is clear that w hen herbicides are applied, selection for those weeds with adaptive mechanisms to escape eliminat ion will survive. If the herbicide is repetitively used in crop production, the surviving weeds will be further selected, and dominant genes as well as multi

- component resistance mechanisms will be selected. While many practices can be used to manage wee ds, the recent history of glyphosate use shows that when the collective knowledge of resistance development is either neglected or practices not sufficiently integrated with mechanical and cultural controls, or with more robust herbicidal strategies, resis tant weeds will arise. As noted earlier, it is not so much herbicide resistant crops that are a cause of herbicide resistant weeds, but from the failure to apply best management practices in the production of herbicide resistant
crops.

Mechanisms of H erbi cide R esistance in W eeds and R elationship to S elective P ressure
Two types of weed resistance may arise following inadvertent weed selection and both confer complex management concerns for growers. The first is target site specific resistance (TSR), and t he second, non

- target site specific (NTSR). The first results in an alteration of the target site of the herbicide so the target is no longer inhibited. The second type of resistance is more general and may confer resistance to a wide range of chemistries . For example, NTSR resistance may provide protection by reduced penetration of the herbicide, altered translocation, overproduction of targets, target mutation, or neutralization of cytoplasmic toxins ( Délye et al.

, 2013 ) . TSR confers resistance usually to a single herbicide, and NTSR may con fer resistance to as many as nine different modes of action (e.g., Lolium rigidum ) and 16 herbicides (Burnet et al., 1994). In the case of NTSR, the use of herbicides on weeds with unknown NTSRs may provide a substantial risk for development of weed resis tance ( Délye et al. , 2013 )

. The target s ite alterations leading to TSR are often produced by dominant or semidominant nuclear mutations and can be found in herbicide G roups 1
, 2
, 3
, 23
, 14 , and 9, while triazine herbicides ( G roup 5 ) result from dominant cytoplasmic mutations ( Délye et al. , 2013 ) . This resistance arises following a sin gle mutation, which because of its beneficial nature promotes immediate survival and is positively and rapidly selected within the agricultural environment. Glyphosate resistance that is TSR is a consequence of one amino acid change at position 106 of the chloroplast EPSPS protein. Worldwide, 14 of these populations have been identified ( Beckie, 2011 )

.
Natural T olerance

Natural tolerance to certain herbicides may be apparent when weeds are first exposed to a herbicide, or with selection, existing genes may be selected and then accumulated to produce varying level s of tolerance ( likely by NTSR) . F ield morning glory ( Convolvulus arvensis L.) has such tolerance to glyphosate and has been assessed in detail (Westwood and Weller 1997). Glyphosate tolerance in Convolvulus was also found in historical populations which predated glyphosate resistant crop introductions ( Baucon and Mauricio, 2010 )

. The pre exposure NTSR to glyphosate was at about the same level as that which is currently observed. Morning glory can also be shown to have pre

- existing resistance ( that is, by TSR) but which is not as high as that expressed by plants now collected ( Baucon and Mauricio, 2010 )

. Both types of resistance can exist in the species, but independently, with resource allocation costs apparent for the plant’s toleran ce mechanisms for the herbicide ( Baucon and Mauricio, 2008 )

. At least some

Page 6

- 5populations of 16 species have been alleged as not controllable by recommended field rates of glyphosate, presumably by natural tolerance mechanisms ( Duke and Powles, 2008 )

.
Weeds Resistant to Multiple Herbicides

Direct resistance of a weed species to an herbicide is an unwelcome consequence of weed selection, but cross resistance to other herbicides in the same class or to other classes of herbicides provides an even greater cons equence to those who manage weeds, since a grower’s choice of herbicide site of action (SOA) will be restricted in the present season’s crop and potentially also in the rotation crop. When resistance is based on non

- target site mechanisms, which may inclu de increased metabolism and reduced translocation to target sites, the weed may be capable of resistance to multiple herbicide modes of action ( Beckie and Tardif, 2012 ) . NTSR appears to arise from a weed’s accretion of variants of several genes which may originally have been subsets of stress

- tolerance genes (see review in Délye ( 2013 ) . Délye ( 2013 ) attributes much of the recently discovered weed resistance to this mechanism, and it is particularly important in Groups 9 (glyphosate) and 1 (acetyl

- CoA carboxylase inhibitors)

, as well as grasses and probably broadleaf weeds ( G roup 2 : acetohydroxyacid synthase inhibitors) . In the case of glyphosate, Beckie ( 2011 ) lists 15 i nstances worldwide of glyphosate NTSR.

Weed S election for R esistance to H erbicides by Overuse

The intense use of glyphosate on field crops compared to decreased use of other herbicides is a trend within the last decade, but how growers use glyphosate in f ield situations makes the situation clearer in grower surveys such as that of Prince ( 2012 ) . These surveys give evidence of the prevalent practices employed by growers in which glyphosate is sometimes the only herbicide used, allo wing the overexposure of crops and weeds to glyphosate. Growers were choosing glyphosate frequently for pre

- plant burndown, but also post

- planting with high frequency, so that repeated exposure of weeds to glyphosate during crop production was common with in the same season. Because the most common rotation crop for corn is soybean, exposure of weeds to selecting doses of glyphosate occurs in consecutive seasons as well.

Because conservation tillage systems are inherently more dependent upon weed managemen t using herbicides, selective pressure on weeds is greater than that on fields using conventional tillage with its greater options for pre

- plant primary tillage and post plant secondary tillage ( Vencill et al. , 2012 ) . In a survey conducted in 2007, growers that planted 87% of th eir crops to glyphosate resistant corn, soy or cotton varied the SOA used on their crops ‘always’ or ‘mostly’ just 39% of the time, with the remaining 61% affirming they did so ‘seldom’ or ‘never’ ( Frisvold et al. , 2009 ) . Thus, when conservation tillage and HR crops define the production system, growers are likely to use the same herbicide (i.e., glyphosate) frequently. Some other options also may be foreclosed by conservation till (especially no

- till), such as soil incorporation of residual herbicides, although some residuals can also be soil applied ( Penn State Extention, 2013 )

. Considering the recommendat ions for success in reducing resistant weed development ( Vencill et al. , 2012 ) , unsuccessful herbicide strategies that have encouraged resistant weeds can include:

Page 6

- 61. H erbicide use of mostly one or a few modes of action ( Norsworthy, 2012 ) and infrequent use of herbicide tank mixes, sequences and diversity ac ross seasons ( WSSA, 2011a )
, 2. I ncorrect timing of herbicide application ( Norsworthy, 2012 )
, 3. F ailure to consider the likelihood th at a weed already has non

- target site resistance mechanisms ( Délye et al. , 2013 ) against specific herbicides (including metabolic potential, ability to prevent translocation, or ability to sequester the herbicide)

. 4. Applying low doses of herbicide thereby a llowing weeds to be exposed to low rates herbicide which encourage s sequential escapes and accumulating resistance genes ( WSSA, 2011b ) ; 5. N ot establishing fields devoid of active weeds at planting or good weed control at canopy closur e (for soybean) because not all available tools and herbicides were used ( Monsanto, 2013 ) ; resulting in poorer crop establishment and more weed initiation

. Weed R esistance from U ndervaluing a B alance of Residual and Contact Herbicides

The decrease in use of soil applied residual herbicides and a focus instead on mainly foliar

applied contact herbicides may be another basic and strategic misapplication of technology by field crop producers and these resulted in resistant weed development . In the era before introduction of HR soybean and corn, and afterwards, production changes by growers were noted in the use of herbicides in the transition to greater HR crop acreage. For soybeans, in 1996, 70% of growers used pre

- emergent herbicides, b ut by 2002 they did so less than 20% of the time ( Livingston and Osteen, 2012 )

. A decline in corn pre

- emergent herbicide use also occurred, from nearly 80% to around 60%. Post

- emergent herbicides were applied to about 80% of soybean in 1996, then steadily increased to nearly 100% in 2010; in corn, post emergent herbicide use incr eased from 60% to 75%. These reflect increased use of glyphosate with its utility as an over the top and POST herbicide on soybean, but also a decline in reliance on pre

emergent non glyphosate herbicides. Likewise, Prince ( 2012 ) concluded that soybean growers were less likely than corn or cotton growers to use a residual herbicide (often pre

- emergent) in their multistate survey of herbicide use in 2005 and 2010. Growers thus lost value from an herbicide by not deploying a residual (soil applied residual in no

- till production) herbicide that has a different SOA than glyphosate, and relying on post

- emergence control using glyphosate or another foliar active herbicide. Perhaps as a consequence of awareness of weed herbicide resistance or in an effort to combat glyphosate resistant crops, use of residual herbicides has increased modestly between 2005 and 2009 from 15% to 27% of soybean acreage ( Owen et al.

, 2011 )

. Related to the issue of reductions in residual pesticide use is that of reductions in numbers of herbicides used in soybean and corn. An USDA Agricultural Resources and Environmental Indicators (AREI) survey showed that soybean growers reached a high point of rotating pesticides to slow resistance evolution in1998, but this declined steadily to low single digits in 2010 ( USDA

- ERS, 2010 ) . Corn growers chose to rotate pesticides to avoid resistance development from a high of 45% in 1998 to about 30% in 2010. Total applications of all herbicides have also decl ined from nearly 3 per year in soybean in 1996 to about 2 in 2006 ( USDA

- ERS, 2010 )

. Although this survey does not tabulate different sites of action applied in these years, it is clear that fewer SOAs were likely employed since overall application rates indicate limited actual use of non

- glyphosate herbicides on soybean.

Page 6

- 7Weeds R esistant to the H erbicides C ommonly U sed on C orn and S oybean.

As of March 21, 2013 , internationally

, there were 397 cases of herbicide resistant weeds in 217 species ( Heap, 2013a )

. The first herbicide

- resistant biotypes were described in the 1950s, but the number of weeds resistant to herbicides increased dramatically in the 1980s and 1990s, and resistance to 21 of the 25 known herbicide sites of action has been identified through out the world ( Heap, 2013a ) . Of the 25 known herbicide sites of action, 11 of these sites of action are commonly used on corn and soy ( See Appendix 4, Table 6

- 3). These sites of action and the particular herbicides commonly used to manage weeds in corn and soybean are listed on the top and bottom, respectively of Table 6

- 3. While there are hundreds of cases of herbicide resistant weeds, most of these weeds are not actively managed in corn and soybean. The analysis below focuses on weeds that are actively managed in corn and soybean fields and addresses which of these have developed herbicide resistance to the major herbicides used in corn and soybean.

Table 6

- 3, below, lists the problem weeds of corn and soybean, derived from survey data noted in Tables 5

- 1 and 5

- 2 in Appendix 5, and indicates whether validated herbicide resistance has been reported for these species as noted in the International Survey of Herbicide Resistant Weeds ( Heap, 2013a ) . Each column represents a different site of action and the WSSA number associated with that site of actio n is also listed on the top of each column. The major herbicides used on corn and soybean are listed below the table and color coded green if used on both corn and soybean, blue if used only on soybean, and yellow if only used on corn. If a particular we ed has been reported to be resistant to any of the herbicides listed below the chart, the herbicide is so indicated for that combination and colored as just described. In cases where herbicide resistance has been noted only outside the U.S., the herbicide is marked with an asterisk. Quizalofop

- p

- ethyl is not among the top ten herbicides used in corn or soybean, but nevertheless is indicated where corn/soybean weeds are resistant. Cells are marked NR, for “not reported,” in cases where resistant weeds aga inst the listed herbicides are not reported on International Survey of Herbicide Resistant Weeds site ( Heap, 2013a ) .The last column lists those cases where weeds have been selected for resistance against more than one herbicide site of action corresponding to the listed herbicides. In those cases, the WSSA Herbicide Group # for the site of action is listed. For example, two types of multiply resistant kochia biotypes have been noted. One is multiply resistant to both ALS (#2) and PSII inhibitors (#5), the other is multiply resistant to ALS inhibitors (#2) and glyphosate (#9).

Page 6

- 8Table 6

- 3 . Herbicide Resistant Biotypes of Problem Weeds in Corn and Soybean.

WSSA herbicide # 2 5 1 4 22 9 3 14 15 27 10 major weeds in corn and soybean ALS PSII ACCase Auxin Bipyridiliums EPSPS Dintro

anilines PPO Chloroacetamides 4

- HPPD GS multiple

BROADLEAF PIGWEED, REDROOT imazethapyr metribuzin 1 N/A NR NR NR NR NR NR NR NR 2+5 Chlorimuron

ethyl atrazine 2+7

chloransulam

methyl simzine 1

thifensulfuron

methyl tribenuron

methyl 1
nicosulfuron 1

LAMBSQUARTERS thifensulfuron

methyl metribuzin N/A dicamba 1 NR NR NR NR NR NR NR NR

tribenuron

methyl 1 atrazine

simzine

WATERHEMP Chlorimuron

ethyl atrazine N/A 2,4

- D NR Glyphosate NR fomesafen NR mesotrione NR 2+5

imazethypyr lactofen isoxaflutole 2+ 1 4 chloransulam

methyl 2+9

thifensulfuron

methyl 2+27

2+5+9 flumetsulam 2+5+ 1 4
nicosulfuron 2+9+ 1 4
rimsulfuron 2+5+27
2+9+27
2+5+ 1 4+27
2+5+9+ 1 4
2+5+9+27
2+5+9+ 1 4+27

COCKLEBUR imazethypyr NR N/A NR NR NR NR NR NR NR NR NR Chlorimuron

ethyl
chloransulam

Page 6

- 9WSSA herbicide # 2 5 1 4 22 9 3 14 15 27 10 major weeds in corn and soybean ALS PSII ACCase Auxin Bipyridiliums EPSPS Dintro

anilines PPO Chloroacetamides 4

- HPPD GS multiple

methyl

RAGWEED, GIANT chloransulam

methyl NR N/A NR NR Glyphosate NR NR NR NR NR 2+9

imazethypyr
Chlorimuron

ethyl

KOCHIA imazethypyr atrazine N/A dicamba NR Glyphosate NR NR NR NR NR 2+5 thifensulfuron

methyl 2+9

tribenuron

methyl rimsulfuron
nicosulfuron

Horseweed Chlorimuron

ethyl atrazine N/A NR paraquat Glyphosate NR NR NR NR NR 2+9

chlo ransulam

methyl simzine 9+22

thif ensulfuron

methyl 5+7 1

tribenuron

methyl 2+5 1

RAGWEE D Chlorimuron

ethyl atrazine N/A NR NR Glyphosate NR flumioxazin NR NR NR 2+ 1 4

chloransulam

methyl simzine fomesafen 2+9

imazethypyr lactofen

Field Bindweed NR NR N/A 2,4

- D NR NR NR NR NR NR NR NR

SUNFLOWER Chlorimuron

ethyl NR N/A NR NR NR NR NR NR NR NR NR

imazethypyr
chloransulam

methyl flumetsulam
THISTLE, CANADA NR NR N/A 2,4

- D 1 NR NR NR NR NR NR NR NR
velvetleaf NR atrazine N/A NR NR NR NR NR NR NR NR NR

Page 6

- 10WSSA herbicide # 2 5 1 4 22 9 3 14 15 27 10 major weeds in corn and soybean ALS PSII ACCase Auxin Bipyridiliums EPSPS Dintro

anilines PPO Chloroacetamides 4

- HPPD GS multiple

dandelion NR NR N/A NR NR NR NR NR NR NR NR NR

HENBIT NR NR N/A N/A NR NR NR NR NR NR NR NR Pennsylvania
SMARTWEED NR atrazine N/A NR NR NR NR NR NR NR NR NR

Russian thistle NR NR NR NR NR NR NR NR NR NR NR NR
Musk thistle 2,4

- D

wild mustard chloransulam

methyl atrazine 1 N/A dicamba 1 NR NR NR NR NR NR NR NR

imazethypyr metribuzin 1 2,4

- D 1
thifensulfuron

methyl
tribenuron

methyl 1 black nightshade NR atrazine NR paraquat NR NR NR NR NR NR NR
simazine

mousear chickweed NR NR N/A NR NR NR NR NR NR NR NR NR hemp sesbania NR NR N/A NR NR NR NR NR NR NR NR NR palmer's amaranth imazethypyr atrazine Glyphosate mesotrione 2+9 Chlorimuron

ethyl 2+5+27

thifensulfuron

methyl sicklepod NR NR N/A NR NR NR NR NR NR NR NR NR prickly sida NR NR NR NR NR NR NR NR NR NR NR NR

wild buckwheat thifensulfuron

methyl NR N/A NR NR NR NR NR NR NR NR NR

tribenuron

methyl 1

Grasses foxtail, giant imazethypyr atrazine clethodim N/A NR NR NR NR NR NR NR NR

n icosulfuron quizalofop

p

- ethyl 2
rimsulfuron
fox tail, yellow imazethypyr atrazine NR N/A NR NR NR NR NR NR NR NR
simzine
fox tail, green imazethypyr 1 atrazine 1 NR N/A NR NR NR NR NR NR NR NR
Page 6

- 11WSSA herbicide # 2 5 1 4 22 9 3 14 15 27 10 major weeds in corn and soybean ALS PSII ACCase Auxin Bipyridiliums EPSPS Dintro

anilines PPO Chloroacetamides 4

- HPPD GS multiple

joh nsongrass nicosulfuron NR quizalofop

p

- ethyl 2 N/A NR Glyphosate NR NR NR NR NR
NR

r imsulfuron 1 clethodim imazethypyr

cra bgrass imazethypyr 1 atrazine 1 clethodim 1 N/A NR NR NR NR NR NR NR NR nicosulfuron 1 quizalofop

p

- ethyl 1 ( 2 )

whe at, volunteer 3 NR NR N/A N/A NR NR NR NR NR NR NR NR

qua ckgrass NR NR N/A N/A NR NR NR NR NR NR NR NR

barnyardgrass imazethypyr 1 atrazine quizalofop

p ethyl 1 ( 2 )

n icosulfuron 1 simzine

oat , wild rimsulfuron 1 NR clethodim 1 N/A NR NR NR NR NR NR NR NR quizalofop

p

- ethyl 2
cupgrass, woolly NR NR N/A N/A NR NR NR NR NR NR NR NR
mil let, wild

- proso NR NR N/A N/A NR NR NR NR NR NR NR NR

san dbur NR NR N/A N/A NR NR NR NR NR NR NR NR panicum, fall NR atrazine 1 NR N/A NR NR NR NR NR NR NR NR

che at 4 NR NR N/A N/A NR NR NR NR NR NR NR NR panicum, texas NR NR N/A N/A NR NR NR NR NR NR NR NR

sic klegrass NR NR N/A N/A NR NR NR NR NR NR NR NR brome, downy NR atrazine 1 clethodim N/A NR NR NR NR NR NR NR NR
simzine 1 quizalofop

p

- ethyl 2

bro me, japanese 4 NR NR N/A N/A NR NR NR NR NR NR NR NR signalgrass, broadleaf NR NR N/A N/A NR NR NR NR NR NR NR
NR

rye grass (italian?) NR NR clethodim 1 N/A NR Glyphosate NR NR NR NR glufosinate NR quizalofop

p

- ethyl 2

watergrass 4 NR NR N/A N/A NR NR NR NR NR NR NR NR
blu egrass, annual NR simzine NR N/A NR Glyphosate NR NR NR NR NR NR
atrazine
Page 6

- 12WSSA herbicide # 2 5 1 4 22 9 3 14 15 27 10 major weeds in corn and soybean ALS PSII ACCase Auxin Bipyridiliums EPSPS Dintro

anilines PPO Chloroacetamides 4

- HPPD GS multiple

Ke y: Commonly used herbicides on corn and soybean

2 5 1 4 22 9 3 14 15 27 10

ALS PSII ACCase Auxin Bipyridiliums EPSPS Dintro anilines PPO Chloroacetamides 4

- HPPD GS
Chlorimuron metribuzin clethodim 2,4

- D paraquat Glyphosate pendimethalin flumioxazin metolachlor

- S mesotrione glufosinate imazethypyr atrazine quizalofop

- p

- ethyl 2 dicamba fomesafen acetochlor isoxaflutole
chloransulam

- methyl simzine clopyralid sulfentrazone thifensulfuron

- methyl saflufenacil tribenuron methyl flutiacet

- methyl flumetsulam lactofen
thiencarbazone

methyl rimsulfuron nicosulfuron

1 outside US only

2 not a top 10 herbicide in either soy or corn

3 ALS resistant varieties through conventional breeding; glyphosate resistant variety identified as volunteers in a single Oregon field though never deregulated.

4 Not resistant to herbicides commonly used on corn and soybean Source: ( DAS, 2013 ; Heap, 2013b )

Page 6

- 13The most widespread resistance is observed for the ALS inhibitors. Five different ALS inhibitors are commonly used on soybean and four are used on corn but none of these herbicides are commonly used on both crops. For this site of action, 12 of the 25 prob lem broadleaf weeds and 7 of the 22 grasses include ALS resistant biotypes. We are not aware if these biotypes exhibit cross reactivity to other ALS herbicides listed or otherwise. From limited survey data, it has been inferred that ALS resistant weeds are present in all soybean fields in the Heartland ( Trane l et al.

, 2011 )

. Also widespread are biotypes resistant to PSII inhibitors which include 11 of the problem broadleaf weed species and eight of the grasses. Most of these cases involve biotypes that have been selected against atrazine in corn or metribuz in in soybean.

ACCase inhibitors are grass specific herbicides and so have not been used on corn. They have been used on soybean and other crops. Clethodim is one of the more commonly used herbicides on soybean. Quizalofop

- p

- ethyl, is not commonly used on soybean but is considered here because Enlist TM corn would also be resistant to that herbicide. Seven of the problem grasses have developed resistance to quizalofop

- p

- ethyl and a subset of six biotypes are also reported to be resistant to clethodim, though for two of these cases, crabgrass, and barnyard grass, resistant biotypes have only been reported outside the U.S.

Glyphosate, 2,4

- D, and dicamba are the three herbicides that are commonly used on both soybean and corn. Of the three, only glyphosate is effective on most grass weeds. Relatively few grass weeds have resistant biotypes so glyphosate remains a very effective herbicide to control grasses. Of the problem weeds in corn and soybean, three: johnsongrass, Italian ryegrass, and annual bluegrass hav e been selected for glyphosate resistance. Glyphosate resistant broadleaf weeds have been more problematic. In this case, resistant biotypes have been selected in five broadleaf species and these resistant biotypes are more widely disseminated especially i n the Southeast. The prevalence of such weeds is increasing and becoming more problematic in the Northern Crescent, Heartland, and Great Plains. Corn/soybean weeds that now have glyphosate resistance include waterhemp, giant ragweed, kochia, horseweed, and common ragweed.

Resistance to g lu f osin a te o ffer s a n a lt er n a tive mode of ac tion to g l y phos a te f or the b r o a d

sp ec t r um c ont r ol of w ee d s in s o y b ea n. T o d a t e , o nl y I t a li a n R y e g ra ss h a s b ee n re p o r t e d as

re sist a nt to g lu f osin a te in the U. S. a nd this biotype is lo ca t e d in Or e g on. H o w e v er , this
p opul a tion of I t a li a n R y e g r a ss a lso a p p ear s to l era nt to g l y pho s a t e. Three problem corn/soybean weeds, lambsquarters, kochia, and wild mustard have dicamba resistant biotypes (though wild mustard is not reported to be resist ant in the U.S.). Four problem corn/soybean weeds, waterhemp, field bindweed, canada thistle, and wild mustard, are reported to be resistant to 2,4

- D (though the Canada thistle and wild mustard biotypes are not reported to be resistant in the U.S.). Resist ance to clopyralid, the other auxin commonly used in corn, has not been reported.

For the other commonly used herbicides on corn and soybean, resistant biotypes have generally not been selected in the problem weeds. The exceptions include horseweed and b lack nightshade resistant to paraquat, waterhemp and ragweed resistant to PPO inhibitors, Italian ryegrass resistant to glufosinate, and waterhemp and Palmer’s amaranth resistant to the 4

- HPPD inhibitors mesotrione and isoxaflutole. There are two sites of action for which we are not aware of any

Page 6

- 14resistant biotypes in the problem weeds. These include the dinitroanilines, such as pendamethalin, and the chloroacetamides such as metolachlor

- S and acetochlor.

A number of the problem weeds have biotypes that are resistant to herbicides corresponding to more than one site of action. The most problematic is waterhemp which is resistant to six of the eleven sites of action commonly used in corn and soybean. Biotypes multiply resistant to 13 combinations of these sit es of action have been reported including one biotype that is resistant to five sites of action ( Owen, 2012 ) . Ragweed, kochia, and horseweed are each reported to have biotypes resistant to four sites of action including biotypes that are multiply resistant to two herbicides. Horseweed has four such bi otypes, kochia and ragweed each have two. Multiply resistant biotypes have also been selected in redroot pigweed and giant ragweed. In total, 7 of the 47 problem weeds include biotypes resistant to more than one herbicide.

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- ERS. 2010. "To p 25 Agricultural Export Commodities, With Level of Processing, by Fiscal Year, Current Dollars." (2010). Web. August 13 http://www.ers.usda.gov/Data/FATUS/#monthly

. Vencill, William K., Robe rt L. Nichols, Theodore M. Webster, John K. Soteres, Carol Mallory

Smith, Nilda R. Burgos, William G. Johnson, and Marilyn R. McClelland. 2012. "Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide

- Resistant C rops." Weed Science 60.sp1: 2

- 30. WSSA.2011a "Lesson 5

- Principles of Managing Herbicide Resistance

- " WSSA Lesson Modules: Herbicide Resistant Weeds . Vol.: Weed Science Society of America, 2011a. 24. Web http://wssa.net/wp

- content/uploads/Lesson_5_HR

- Turf.pptx

. WSSA. 2011b. "Weed Science Society of America." Weed Science Society of America April 18, 2011 2011b. Web. May 25 2011 http://wssa.net/wp

- content/uploads/WSSA

- Mechanism

of

- Action.pdf

.

Page 6

- 17

### Off

- Target Pesticide Movement Appendix 7.

Page 7

- 1Off

- T arget P esticide M ovement
Once applied, pesticides (which include herbicides) that are not taken up by targeted plants that have been harvested will persist, degrade, or move in the environment. The potential environmental fate of an herbicide is shown in Figure 7

- 1. Degradation occurs by hydrolysis, photolysis, or microbial dissipation resulting in the herbicide being broken down and losing its herbicidal activity. Herbicides can be transporte d from their original application site by spray drift, runoff, leaching, volatility, wind erosion, or crop removal. Off

- site movement of herbicides have the potential to impact non

- target plant and animal communities living in proximity to fiel ds in which herbicides are used, as well as human populations.

Figure 7

- 1

. Environmental fate of herbicides in the environment.

Pesticide use has the potential to affect soil quality due to the impact to the soil mic robial community. The length of persistence of herbicides in the environment depends on the concentration and rate of degradation by biotic and abiotic processes ( Carpenter et al. , 2002 )

. Persistence is measured by the half

- life or dissipation time (DT 50 ), which equates to the length of time needed for the herbicide to degrade to half of its original concentration.

Use of herbicides for field crop production may introduce these chemicals to water through spray drift, cleaning of pe sticide application equipment, soil erosion, or filtration through soil to groundwater. Irrigation and rainfall occurring the first few days after herbicide application can influence herbicide loss through leaching and runoff. However, it has been estima ted that even after heavy rains, herbicide losses to runoff generally do not exceed 5 to 10 percent of the total applied ( USDA

- NRCS, 2000 ; Tu et al. , 2001 )

. Planted vegetation, such as grass buffer strips, or crop residues can effectively reduce runoff ( Fishel, 1997 ; USDA

- NRCS, 2000 )

. Pesticides applied to crops may volatilize, thereby introduci ng chemicals to the air. Volatilization typically occurs during application, but herbicide deposited on plants or soil can also volatilize. Volatilization occurs when pesticide surface residues change from a solid or

Page 7

- 2liquid to a gas or vapor after appli cation. V ol a tili z a tion refer s to the t ra ns f o r m a tion of a liquid or solid p e sti c ide i nto a g a s. T he e x t e nt of vol a tili z a tion is d e p e nd e nt on p r op er ti e s of the c h e mi ca l

a nd h er bi c ide f o r mul a tion, a nd e nvi r o n m e nt a l fac to r s s u c h a s a ir t e mp era tu r e , w ind sp ee d, a nd

r e l a tive hum i di t y

. V ol a tili z e d p e sti c id e s ca n be c a rr i e d b y a i r c u rre nts pot e nti a l l y l ea ding to o f f

t ar g e t e x posu re . Once airborne, volatilized pesticides may be carried long distances from the treatment location by air currents. The higher the vapor pressure of a chemical, the more volatility it exhibits. In addition, other physical and chemical pesticide properties, agricultural practices, meteorological conditions, persistence of a pesticide on plant surfaces, and soil properties influence th e extent of volatilization ( University of Missouri, 1997 ; US

- EPA, 2012c )

. Most of the herbicides considered highly volatile are no longer used ( Tu et al. , 2001 )

.

Dr i f t is the p h y si ca l mov e m e nt of s p r a y d r opl e ts moving o ff

- s ite a s a c h e mi c a l a ppli ca t ion is

m a d e

. U nd er cer t a in c onditions, the p o t e nti a l f or p h y s i ca l d r i f t f r om a n a ppli ca tion site to

a dj ace nt non

- t a r g et e nvi r onm e nts is possible f or a ll t y p e s of p e sti c ide sp r a y a ppli ca tions. T his is

a n a ppli ca tion

- re l a t e d ph e no m e non ind e p e nd e nt of the c h e mi ca l p e sti c id e , w hi c h m a y be i n f lu e n ce d b y the f o r mul a tion in g r e di e nts a nd sp r a y mix a dditiv e s. Spray drift is a concern for

non

- target susceptible plants growing adjacent to fields when herbicides are used in the production of any crop. This potential impact relates to exposure of non

- target susceptible plants to the off

- target herbicide drift ( Jordan et al. , 2009 )

. Damage from spray drift typically occurs at field edges or at shelterbelts (i.e., windbreaks), but highly volatile herbicides may drift further into a field. The risk of off

- target herbicide drift is recognized by EPA, which has incorporated both equipmen t and management restrictions to address drift o n EPA

- approved herbicide labels. These EPA label restrictions include requirements that the grower manage droplet size, control spray boom height above the crop canopy, restrict applications under certain wi nd speeds and environmental conditions, and use drift control agents ( Jordan et al. , 2009 )

. The amount of drift varies widely and is influenced by a range of factors, including weather conditions, topography, the crop or area being sprayed, application equipment and methods, and practices followed by the applicato r ( US

- EPA, 2000 )

. EPA’s Office of Pesticide Programs (OPP), which regulates the use of pesticides and herbicides in the U.S., encourages pesticide applicators to use all feasible means available to minimize off

- target drift. EPA

- OPP has introduced several initiatives to help ad dress and prevent the problems associated with drift. Currently, EPA

- OPP is evaluating new regulations for pesticide drift labeling and the identification of BMPs to control such drift ( US

- EPA, 2009 ) , as well as identifying sci entific issues surrounding field volatility of conventional pesticides ( US

- EPA, 2010 )

. Additionally, EPA

- OPP and its Office of Research and Development are developing a new voluntary program, the Drift Red uction Technology (DRT) Program, which encourages the development, marketing

, and use of application technologies verified to significantly reduce spray drift ( US

- EPA, 2009 )

. EPA’s core pesticide risk assessment and regulatory processes ensure that protections are in place for all populations of non

- target species potentially exposed to pesticides, including humans. These assessments provide EPA with information needed to develop label use restrictions for the pesticide. G rowe rs are required to use pesticides, such as 2,4

- D and quizalofop, consistent with the application instructions provided on the EPA

- approved pesticide label. Labels can include restrictions related to minimizing drift or exclusion distances from bodies of w ater when necessary. These label restrictions carry the weight of law and are enforced by EPA and the states ( FIFRA 7 USC 136j (a)(2)(G) Unlawful Acts).

Page 7

- 3In the comments to the EA on 2,4

- D resistant corn and soybean, the issue was raised whether the increase in 2,4

- D use expected from the adoption of EnlistTM corn and soybean would result in greater off

- target effects to neighboring crops and thereby increase adverse socioeconomic impacts to these farmers. A group, Save Our Crops Coalition (SOCC), comp rised of fruit and vegetable growers in the Heartland, petitioned the USDA to conduct an EIS regarding the deregulation of EnlistTM corn and soybean, because of their concern that off target movement of 2,4

- D would damage their crops. In this appendix, we c onsider the EPA’s regulation of off

- target pesticide movement, the recorded cases of 2,4

- D damages to neighboring farms, and the changes requested by DAS for the registration of EnlistTM products aimed at mitigating off

- target pesticide movement.

2,4

- D and o ff

- targ e t m o ve m e nt

Sin c e it wa s int r odu ce d i n 1948, th er e h a v e b ee n r e po r ts of 2,4

- D a dv er s e l y aff e c ting no n

- t a r g et b r o a dl e a f f ood a nd fee d c r ops, su c h a s c otton, g r a p e s a nd tom a to e s, g r o w i n g in the vi c ini t y of
t ar g e t cr ops ( Schultz et al. , 1956 )

. Su c h in c id e nts h a ve b e e n link e d to d r i f t of sp r a y d r opl e ts (e sp ec i a l l y th r o u g h aer i a l sp r a y i n g) or d r i f t o f v a po r s f o r m e d b y vol a tili z a tion of the 2,4

- D its e l f ( Dexter, 1993 )

.

I n cr e a s e d c on t r ol of d r i f t a nd v ol a tili z a tion acr oss p e sti c id e s h a s b ee n ac hi e v e d w ith p r op e r

e quipm e nt s e tup a nd a tt e ntion p a id to c lim a tic c onditions a t the time of a ppli ca tion. U niv er si t y

e x t e nsion a g e n c i e s h a ve b ee n e sp e c i a l l y p r omin e n t in d e v e loping a nd diss e min a ting “G ood A ppli ca tion P rac ti ce s ” to minim i z e d r i f t. A dditio n a l l y , p e sti c ide l a b e l re st r i c tions, st a te p e sti c ide

r e g ul a tions, no zz le t ec hnolo g y a nd m a n u fac t u re r s t ewar dship p r o g r a ms h a v e h e lp e d to d e v e lop

a nd e st a blish a ppli ca tion p rac ti ce s t h a t minimi z e t he pot e nti a l f or o f f

- t a r g e t e x posu re

. The herbicide 2,4

- D is currently available in several formulations, including 2,4

- D acid, 2,4

- D sodium salt, 2,4

- D diethyl amine, 2,4

- D dimethylamine salt, 2,4

- D isopropyl acid, 2,4

- D triisopropyl acid, 2,4

- D butoxyethyl ester), 2,4

- D ethylhexyl ester, and 2,4

- D isopropyl ester ( US

- EPA, 2005c )

. In 2011, EPA approved the first new use of the 2,4

- D choline salt formulation

on crops, including corn and soybean ( US

- EPA, 2011 )

. The 2,4

- D mode of action as a synthetic auxin is not changed by these formulations, but the chemical and physical properties of each formula tion influence the selection of equipment, mitigation measures adopted in the field to minimize off

- target impacts, and formulation

- specific safety measures. 2,4

- D is formulated primarily as an amine salt in an aqueous solution or as an ester in an emulsif iable concentrate ( US

- EPA, 2005c )

. For a major ity of use s, 2,4

- D is combin ed with other herbicides because it economically enhances the weed control spectrum of many other herbicides such as glyphosate, dicamba, mecoprop, and acetolactate synthase ( ALS )

- inhibitor herbicides ( US

- EPA, 2005c )

.
A tt r ibutions of vol a tili t y to 2,4

- D h a ve l ar g e l y b ee n a sso c i a t e d w ith the e st er s, p ar ti c u l a r l y sho r t

c h a in e st er s. E ar l y f o r ms of 2,4

- D in c lud e d sho r t c h a in e st e r s th a t wer e fa vo r e d due t o ra pid h er bi c i d a l ac tivit y , but th e se we r e re l a tiv e l y vol a til e ( Nice et al. , 2004 )

. A d e si r e to re d u c e r isk of

o ff

- t a r g e t inju r y to s e nsitive cr ops, su c h a s c otton, tom a to e s or g ra p e s, l e d to the d e v e lopm e nt of lon g e r c h a in e st er s t h a t wer e no t a b l y l e ss vol a til e , a nd to d e v e lopm e nt of v ar ious a mine s a lts th a t E PA c onsid er s to be e ss e nti a l l y non

- vol a til e

. T he vol a tili t y o f the s a lt f o r ms a pp r o ac h e s t w o

o r d er s o f m a g nitude re du c tion c om p are d to the sho r t c h a in e st er s ( US

- EPA, 2013 )

. I n the l a st

Page 7

- 4t w o d e ca d e s, long e r c h a i n e st er s h a ve re p l ace d t h e sho r t e r c h a in e st er s a nd reduced volatility issues

. In addition, the new 2,4

- D choline salt further reduces the potential for volatility.

F e d e r al and S t a t e R e gula t ion of O ff

- t a r g e t P e s t i c ide M o v e me nt ( DAS, 2013 )

E PA is the fe d e r a l a g e n c y v e st e d w ith the a utho r i t y a nd re sponsibili t y f or r e g u l a ting the s a l e , dist r ibution a nd use of p e sti c id e s, in c luding h er b i c id e s su c h a s 2,4

- D

. E PA r e g ist er s or a p p r ov e s

a p e sti c ide f or o n e or m o r e us e s on l y af t e r d e t e r mining th a t the p r od u c t w ill not ca use

un rea son a b l e a dv e r se e f f

ec ts on the e nvi r onm e nt

– the st a tuto r y t e st f o r r e g ist ra tion und e r F I F R A

. W h e n E PA a pp r ov e s the r e g ist ra tion of a p e sti c id e , it a pp r ov e s a p ar ti c ul a r p r od u c t f or a p ar ti c ul a r use o r us e s un d e r sp ec i f i e d c onditions ( in c luding c omposition, a p pli ca tion m e thods,

us a ge ra t e s, a nd p r ot e c tive m ea su r e s) a nd s p ec i f i e s the l a n g u a g e th a t must a pp ea r on the l a b e l of the p e sti c ide p r odu c t th a t s e ts f o r th those c onditions a nd limit a tions. I f a p e sti c ide p r odu c t is

us e d in a m a nn e r t h a t is in c onsist e nt w ith its l a b e l i n g , the u s e r is subj ec t to fe d e r a l a nd st a te

e n f o r c e m e nt a c tion. W h e n m a king its re g ist ra tion d ec ision, E PA sp ec i f i e s the d a ta a nd in f o r m a tion it n ee ds to suppo r t th a t r e g ist ra tion. A mong the d a t a E PA re qu i re s a r e those re l a ting
to o ff

- t a r g e t p e sti c ide m o v e m e nt in c ludin g , e

. g ., sp r a y d r i f t a nd vol a tili z a tion ( 40 C F R p ar t 158, Subp ar ts L a nd N)

.

F e d e ra l l a w re qui re s E P A to p er iodi ca l l y re v i e w e x isting p e sti c ide r e g ist r a tions to e nsu r e th a t th e y m e e t the F I F RA st a nd ar d f or r e g ist ra tion ( t h e " no u n rea so n a ble a d v e r se ef f

ec t s " cr it e r ia of F I F R A ) und e r c u r r e nt s c i e nti f ic st a nd ar ds. E PA s p ec i f i ca l l y a d d re ss e d iss u e s r e g a r ding o ff

- site
p e sti c ide mov e m e nt of 2
, 4

- D in E P A’ s 2005 R er e g ist ra tion E li g ibili t y Dec i sion ( R ED ) f or 2,4

- D ( US

- EPA, 2005c ) , w hi c h in c o rpo r a t e d m a j o r l a b e l re visions to p r od u c t s c ont a ining 2, 4

- D

. T h e se

re visions in c lud e d:

• lo we r limits f or sp r a y d r o pl e t si z e ;

• p r ohibitions on sp r a y i n g a t w ind sp ee ds g r ea t e r t h a n 15 mph,

• sp r a y i n g w ith a w ind di rec tion th a t is not fa vo r a ble to on

- t a r g e t d e position, or sp r a y i n g

w ith s e n s itive non

- t ar g e t cr ops w ithin 250 f ee t do w n w ind;

• a p r ohibition on sp r a y i n g a t w ind sp ee ds of l e ss t h a n 3 mph if th er e ar e t e m p era tu r e inv er sion c onditions, or st a ble a tmosph er ic c onditions a t or b e low no zz le h e i g ht;

• a p r ohibition on sp r a y i n g w h er e s e nsitive cr ops mi g ht oth e r w ise be sus c e ptible to d r i f t;

• re st r i c tions on boom l e ngth a nd sp r a y r e l ea se h e i ght f or aer i a l a ppli ca tions, a nd no zz le h e i g ht f o r g r ound boom a ppli ca tions;

• lo we r limits on a ppli ca tion ra t e s a nd tot a l a ppli ca tions p e r y e a r f or sp e c i f ic cr ops

• c ompli a n c e w ith a n y st a t e a nd lo ca l l a w s th a t a r e mo r e st r ing e nt (e

. g ., C a l i f o r ni a , a r ea s of

w hi c h h a ve s e a son a l limit a tions on use of 2,4

- D ) ( US

- EPA , 2005c )

E PA d e t er min e d the use of the th e n

- e x isting f o r m ul a tions of 2,4

- D to be e l i g ible f or

rer e g ist r a tion w ith those l a b e l re st r i c tions. St a t e s a lso r e g ul a te t h e use o f p e sti c id e s, in c luding
Page 7

- 5h e r bi c id e s. A numb e r of st a t e s h a ve p a ss e d l a w s to sp ec i f i ca l l y a dd r e ss sp r a y d r i f t ( Feitshans, 1999 )

. T h e se l aw s m a y i n c lude p e n a lti e s a nd/or r e st r i c t a ppli ca tion m e thods, re qui r e p r ior noti f i c a tion, impose bu ff e r z on e s, e t c ., a s eac h s t a te h a s d e e m e d a pp r op r i a t e.

I n a ddition to r e g ist er i n g individu a l p e sti c id e s, E PA a lso r e g ul ar l y a ss e ss e s the s afe t y of p e sti c ide

use mo r e b r o a dl y , a nd h a s re p ea t e d l y a d d re ss e d issu e s a sso c i a t e d w ith o ff

- t a r g et p e sti c ide

mov e m e nt. As stated on their web site ( http:// www

. e p a

. g ov/ p e sti c id e s/ fac ts h e e ts/sp r a y d r i f t.htm .) s ome of th e se e ff o r ts in c lu d e :

• I n 2009, E PA d e v e lop e d a nd issu e d f or public c o mm e nt a d raf t g uid a n c e d o c um e nt ( PR N oti ce ) on P e sti c ide Dr i f t L a b e ling to p r ovi d e g uid a n c e to p e sti c ide m a nu f ac tu r e r s on l a b e ling st a t e m e nts c on c er ning p e sti c ide d r i f t, a n d to in f o r m the public of E P A’ s poli c i e s

w ith re g ar d to p e sti c ide d r i f t. E PA c ontinu e s to w o r k w ith st a k e hold er s to f i n a li z e this g uid a n ce.

• F or m a n y y e ar s E PA h a s c ont r ibut e d f undi n g to suppo r t e du ca tion a nd t r a i n ing p r o g r a ms on d r i f t m a n a g e m e nt. E P A p r ovid e s a nnu a l f unds to st a t e s to suppo r t p e sti c ide a ppli ca tor t ra ining p r o g ra ms, m a n y of w hi c h in c lude e d u ca t i on a l m a t er i a l on d r i f t m a n a g e m e nt, a nd E PA h a s c ont r ibut e d to oth e r e du c a tion a l p r o g ra m s, su c h a s the Na tion a l C o a lition on Dr i f t Minimi z a tion e du ca tion a l vid e o a nd C D

- Rom, the Na tion a l P e sti c ide A ppli ca tor C er ti f i ca tion Co r e M a n u a l, a nd the Na tion a l A g r i c ultu ra l A vi a tion A sso c i a tion ’ s P r o fe ssion a l Aer i a l A ppli ca tor Suppo r t S y st e m ( P AA SS) to suppo r t th e ir t ra ining a nd

e du ca tion p r o g r a ms to r e du c e d r i f t in c id e nts.

• E PA e n c ou r a g e s p e sti c i d e a ppli ca to r s to use a ll f e a sible m ea ns a v a il a ble to th e m to minim i z e o ff

- t a r g e t d r i f t. T o suppo r t this g o a l, E P A h a s st a t e d its int e nt to w o r k w ith

a ppli ca to r s, a g r i c ultu ra l e x t e nsion a g e nts, r e g ist ra n ts, e nvi r onm e nt a l g r oups, a nd oth e r int ere st e d st a k e hold e r s to c oll ec t a nd d e v e lop in f o r m a tion on b e st m a n a g e m e nt p rac ti c e s ( B MPs) to re d u c e o f f

- t a r g e t d r i f t f or sp e c i f ic a ppl i ca tion m e thods a nd cr op s ec tor

c ombin a tions. T h e se g uid a n c e d o c um e nts w ill be c onsolid a t e d b y E PA a nd m a de

a v a il a ble onlin e

.

• O PP a nd the E P A’ s Off i c e of R e s e a rc h a nd De v e lopm e nt ar e d e v e loping a n e w volunt a r y p r og ra m, the D r i f t R e du c tion Tec hnolo g y (D R T ) P r o g r a m, w hi c h e n c ou r a g e s the d e v e lopm e nt, m ar k e ti n g , a nd use of a ppli c a tion t e c hnolo g i e s, v e r i f i e d to signi f i ca nt l y

re du c e s p r a y d r i f t ( US

- EPA, 2012a )

.

• E PA h a s a lso t a k e n a c tion to a dd re ss issu e s ar ou n d p e sti c ide vol a tili t y

. I n Dece m b e r 2009, E PA c onv e n e d the F I F RA S c i e nti f ic A dvis o r y P a n e l ( S A P) to e x a mine s c i e nti f ic issu e s a sso c i a t e d w ith f i e ld vol a tili z a t ion of c onv e ntion a l p e sti c id e s, f o c us i ng on

m e thodolo g i e s b y w hi c h b y st a nd e r inh a l a tion c ou l d be m ea su r e d.

Existing pr ec auti o ns a g ainst o ff

- targ e t e xposure ( DAS, 2013 )

De spite fe d era l a nd s t a te c ont r ols a nd the b e st e ff o r ts of a ppli ca to r s, o f f

- t a r g e t p e sti c ide

mov e m e nt o cca sion a l l y d a m a g e s n e i g hbo r i n g cr o p s. C r ops m a y be e x pos e d to p e sti c ide vol a tili t y or d r i f t fr om a v ar i e t y of sou r ce s, in c lu d ing public r i g ht of w a y u s e s f or r o a d

Page 7

- 6m a int e n a n c e a nd utiliti e s, a nd a g r i c ultu r a l us e s. C r ops th a t h a ve the pot e nti a l f or d a m a g e due to

e x posu r e to a p ar t i c ul a r p e sti c ide ar e c onsi d ere d s e nsitive c r ops. S e n sitive cr ops to 2,4

- D include cotton, grapes, and many fruits and vegetables.

G r o w e r s use a numb e r o f a pp r o a c h e s to p r ot ec t th e ir c r ops fr om o ff

- t ar g e t e x posu re

. L o c a tion of

w h e re the cr op is g r o w n is a k e y c onsid e ra tion; s e nsitive cr op g r o w er s m a y c hoo s e to pl a nt in f i e lds th a t ar e sh e lt e re d or p r ot ec t e d fr om pot e nti a l e x posu re , a nd ar e not imm e di a t e l y a dj ace nt to

c onv e ntion a l cr op s ( Mohr )

. B u f fe r z on e s a nd v e g e t a tive b arr i er s ar e o f t e n us e d a s a no sp r a y

z one b e t wee n a s e nsitive a r e a a nd a cr op b e i n g sp r a y e d

. A bu ff e r z one m a y be a v e g e t a tive b a rr i er c onsisting of g r o v e s, h e d g e r o w s, w ind b r ea ks, p a stu re s, or e v e n t h e g r o we r’ s o w n

c on v e ntion a l cr ops. V e g e t a tion pl a nt e d in st ra t e g i c lin e s ca n r e du c e the e x t e nt of sp r a y d r i f t of

a g r i c ultu r a l c h e mi ca ls b y f ilt er i n g o u t sp r a y d r opl e ts in a ir p a s sing th r o u g h th e ir f oli a g e ( Department of Primary Industries )

. I n some c a s e s, g r o wer s ar e a ble to s e l ec t a s e nsitive cr op

v a r i e t y t h a t is l e ss s e nsitive to p e sti c id e s th a t ar e c ommon l y a ppli e d to n e i g hbo r i n g ar e a s. Modi f i e d c ultu ra l p r a c ti ce s, in c l u ding timing of op era tions, a r e a noth e r a pp r o ac h th a t c a n be u s e d to p r ot ec t a g a inst o f f

- t a r g e t e x posu re ( Maynard et al. , 2012 )

.
S e nsitive cr op g r o w e r s m a y help to a void e x posu r e in r i g h t of w a y a r ea s b y posti n g si g ns a nd

m a ki n g arra n g e m e nts w ith g o v e r nm e nt r o a d c r ew s or utili t y c omp a n i e s to do th e ir o w n

m a int e n a n c e of ea s e m e nts a nd r o a d w a y s n ea r th e ir s e nsitive cr op s

. Simil ar l y , n e i g hb o r i n g far ms

ca n b e noti f i e d of the p re s e n c e o f s e nsitive cr ops th a t r e qui r e p r o t ec tion fr om h er b i c ide sp ra y d r i f t a nd vol a tili t y . Sin c e a ppli ca tions of h e r bi c id e s ar e i n cr e a sin g l y b e ing m a d e b y c ustom

a p p li ca to r s, si g n a ge pl ace d n e a r f i e ld e nt ra n c e s a l er ti n g op e r a to r s to the p re s e n c e of s e nsitive

c r ops a nd th a t no sp r a y s ar e a llo w e d, a r e a lso us e d. A lt er n a tiv e l y , s e nsitive cr op g r o wer s m a y noti f y the lo c a l c oops a nd a ppli ca to r s di r e c t l y

. Some states have a pesticide sensitive crop registry and locator. Driftwatch ( Driftwatch ) is a national online tool for identifying specialty crop sites and to further enhance communications between producers of specialty crops and pesticide applicators that promote awareness and stewardship activities to help prevent and manage drift effects that sometime occur from spray operations. It currently includes the states of Colorado, Illinois, Indiana, Michigan, Minnesota, Missouri, Montana, Nebraska, and Wisconsin. This site features an easy

- to

- use Google MapsTM interface that clearly shows applica tors the locations of registered areas so they can utilize the information in their ongoing stewardship activities before they spray . Other states, such as Maryland maintain their own, voluntary, pesticide

- sensitive crop registry ( http://mda.maryland.gov/P ages/homepage.aspx ).

I f cr op d a m a g e o cc u r s, a f fec t e d g r o wer s ca n s e e k c omp e ns a tion b y a v a r i e t y of m e c h a nisms. T he
p e sti c ide a ppli c a tor m a y h a ve insu ra n c e to c o v e r su c h loss es. In many cases, growers work out an equitable settlement. Where this is not possible, state p e sti c ide e n f o r c e m e nt bu rea us a r e noti f i e d
to v i e w a nd do c u m e nt the d a m a g e

. EPA obtains reports of pesticide incidents from private citizens, poison control centers, states, and other government and non

- governmental organizations. I n some st a t e s, t h e a ppli ca tor m a y b e subj ec t to f in e s or oth e r p e n a lti e s ( Feitshans, 1999 )

. T he cr op d a m a g e m a y a lso g ive r ise to c l a ims f or l e g a l d a m a g e s in p r iv a te l aw s u its.

Recorded Cases of D amages from O ff

- target E xposure to 2,4

- D ( DAS, 2013 )

Page 7

- 7USDA is not a w a r e of a c omp re h e nsiv e , n a tion a l d a t a b a se of o ff site in c id e nts fr om p e sti c ide us e. I n c i d e nts involving a ll e g e d p e sti c ide sp r a y d r i f t m a y be re po r t e d b y v ar ious sou rce s to the g r ow er , a ppli c a to r , re t a il er , st a te or fe d era l a g e n c y a nd/or the p r odu ct m a nu fac tu r er ( US

- EPA, 2007 )

. I n f o r m a t i on a sso c i a t e d with the a l l e g e d in c id e nts a nd inv e s t i g a tions is m a n a g e d b y e ac h

r e sp e c tive p ar t y or e nti t y

.

P e sti c ide p r odu c t r e g ist r a nts ar e re qu i re d und e r F IF R A S ec tion 6 ( a )( 2) to s ubmit cer t a in t y p e s of fac t u a l in f o r m a t i on to the U. S . Envi r onm e nt a l P r ot ec tion Ag e n c y ( E P A) r e g a r ding a dv er se ef

f

ec ts on hum a n h ea lth or the e nvi r on m e nt fr om the use of th e ir r e g ist e r e d p r odu c ts. If the incidents are “minor” they are included in the Aggregate Incidents Database and are not included in the Ecological Incident Information system (EIIS) ( US

- EPA, 20 07 ) . EIIS includes information on all ecological incidents reported to the agency prior to 1998 and all major incidents reported since. For plants, a major effect is one that is alleged to have occurred on more than 45% of the acreage exposed to the pe sticide ( US

- EPA, 2005b )

. E I I S a lso in c lud e s in f o r m a t ion on in c id e nt re po r ts s u bmitt e d th r ou g h oth e r sou rce s, s u c h a s the S t a t e s, r e g ar dl e ss if
t h e y ar e " m a jo r " in c id e nts or not. I n c i d e nts of a dv er se ef f

ec ts on l a wns a nd oth e r o r n a m e nt a ls

c a us e d b y di r ec t a ppli c a tion of p e sti c ide p r odu c ts ar e n ot e nt e r e d into E II S

. W h e n a v a il a bl e , E I I S in c lu d e s d a te a nd lo ca tion of in c id e nt, t y pe a nd m a g nitude of e f fec ts ob s er v e d i n v ar ious sp ec i e s,

u s e( s) of p e sti c id e s known or susp ec t e d o f c o nt r ibuting to the in c id e nt. How e v e r , the d a t a b a se

c ont a ins a limit e d numb e r of re p o r t e d in c i d e nts a nd is not rea di l y a v a il a ble to the publi c

.
Re g ist ra nts r out i n e l y submit re po r ts on a ll e g e d in c id e nts th a t h a v e not b ee n ind e p e nd e nt l y

v er i f i e d. Thus, due to the n a tu r e o f in c id e nts a nd how th e y ar e t y pi ca l l y re po r t e d th r o u g h the F I F R A 6 (a)( 2 ) p r o c e ss, the a uth e nti c i t y , v a lidi t y , a nd/or acc u r a c y of in f o r m a tion c ont a in e d in the

re po r ts c a nnot be g u a ra nt ee d b y the r e g ist ra nts a nd m a y not acc u r a t e l y r ef l ec t ac tu a l i n c id e nts

a nd p r odu c ts i n volv e d. I n m a n y ca s e s th er e is not e no u g h in f o r m a tion to d e t er mine if the a ll e g e d

a d v er se ef f

ec ts not e d w e r e in f a c t the re sult of p e sti c ide sp r a y d r i f t a nd not a noth e r c ont r ibuti n g fac to r . Thus, sp r a y d r i f t a ll e g a tions m a y be re po r t e d a s pl a nt d a m a g e whi c h m a y , in fac t, h a ve b ee n c a us e d b y dis ea s e s, ins ec ts, nut r i e nt d ef i c i e n c i e s, h er bi c i d e r e sidue (ca r r y ov e r ) a nd g r o wing

c onditions. F or its p ar t, E P A do e s n o t re qui r e r e po r ti n g of a d v er se e ff e c ts to non

- t a r g e t pl a nts a t the use site wh e n the p e sti c ide l a b e l p r ovid e s a d e q u a te n o ti ce . As a r e sult, some in c id e nts m a y not be re po r t e d b e c a use E P A is a l rea d y a w a r e of the p ot e nti a l f or those e f fec ts t o o cc ur und e r

cer t a in c onditions. It should be noted that none of the reports includes 2,4

- D formulated with choline, a formulation designed to be less susceptible to drift, as the registration of this formulation was only recently a pproved by the EPA.

W hile acc u ra t e , c omp re h e nsiv e , a nd r e li a ble n a ti o n a l d a ta on o ff site in c i d e nts fr om p e sti c ide use is not rea di l y a v a il a b l e , E P A ’ s O ff i c e of P e sti c ide P r o g r a ms m a y publish in c id e nt d a ta a s p ar t of its p er iodic re v i e w o f a ll p e sti c id e s to e nsu r e t h a t th e ir r e g ist ra tions c o n tinue to m ee t c u rre nt

s c i e nti f ic st a nd a r ds. R ece nt l y , E P A publ i sh e d a s c opi n g do c um e nt f or 2,4

- D ac id, s a lts, a nd

e st er s to supp o r t r e g ist ra tion re vi e w th a t in c lud e s the re sults of a s earc h o f the E I I S a nd the A g g r e g a te I n c id e nt R e po r ts d a t a b a s e s f o r ec ol o g i ca l in c id e nts inv o lving 2,4

- D ac id a nd its f o r m s ( US

- EPA, 2012a )

. They reported that, for all years, there were 422 incidents involving plants in the EIIS and 13,798 incident reports for all forms of 2,4

- D in the Aggregate Incident Report database. From the details provided in the EPA summary of the EIIS reports, m a n y of the pl a nt in c id e nts a pp e a re d to re s ult fr om ov er

- a ppli c a tion of 2,4

- D p r od u c ts to l a wns or a ppli ca tion of 2,4

- D p r od u c ts to t y p e s of plants th a t a r e s e nsitive to 2,4

- D. Oth e r p l a nt in c id e nts w er e t h e re sult

Page 7

- 8of sp r a y d r i f t in a g r i c ultu ra l s e ttin g s. Detailed information was not provided for the Aggregate Incident reports.

2,4

- D use restrictions

E P A ' s r e g ist ra ti o n f or 2 ,4

- D un d e r s e c tion 3 of F I FR A in c lud e s c e r t a in re st r i c tions on use th a t

a pp e a r on the p r odu c t ' s l a b e l, but E P A h a s not c l a ssi f i e d 2,4

- D a s a “ r e st r i c t e d use p e sti c id e ” ( R U P ) . The most fre q u e nt m e a ns b y whi c h E P A a dd re ss e s pot e nti a l a d v er s e ef f

ec ts is th r ou g h

w ar ni n g s, p r ohi b itions, re st r i c tions a nd di rec tions f or use on the p r o du c t l a b e l ( 40 C F R P ar t 156 )

. W h e n r e g ist er i n g a p r odu c t, the E P A a lso h a s the a bility to c l a ssi f y a p e sti c ide a s a R UP should it d ee m th a t the p r odu c t n ee ds a ddition a l re st r i c t ions to d ecrea s e the r isk of a dv e r se e ff e c ts ( 40 C F R s ubp ar t I , 15 2 .160 )

. R U P s ca n on l y b e a ppli e d b y o r und e r the di r e c t sup er vis i on of a n

a ppli ca t o r c e r ti f i e d b y t h e st a te or E P A ( DAS, 2013 )

.
A f t e r a p e sti c ide is r e g ist ere d b y E P A, st a t e s ca n r e g ist e r p e sti c id e s und e r sp e c i f ic st a te p e sti c ide

r e g ist ra tion l a ws. S t a te l ea d a g e n c i e s h a ve p r im a r y a utho r i t y f or p e sti c id e s us e d within the st a t e

. I n some ca s e s, st a t e s m a y e n ac t a ddition a l re st r i c tio n s f or use of a p r odu c t to m ee t the us e s a nd

n ee ds of th e ir st a t e

. For example in Northeast Arkansas

, rice, a crop where 2,4

- D was used for weed control, and cotton, a 2,4

- D sensitive crop, are grown in proximity. In 2006, the Arkansas State Plant Board (ASPB) re ceived more than 100 complaints about 2,4

- D drift ( Bennett, 2006 )

. The greater than usual drift was attributed in part to a v e r y w e t sp r ing ( USDA

- NASS, 2006 ) whi c h re sult e d in m a n y a ppli ca tions of 2,4

- D b e i n g c ondu c t e d aer i a l l y a nd do n e in a s h o r t p er iod of tim e

. The ASPB created a 2,4

- D task force and a glyphosate task force in 2006 charged with the mission of developing proposed regulations for the board to consider ( Bennett, 2007 )

. After conducting public meetings and taking testimony from representatives from various agriculture sectors, the task forces submitted recommendations to the ASPB at t he end of 2006. The final rule, adopted in February 2007, called for a ban on most aerial and ground spray applications of 2,4

- D in ten northeastern counties (area known as Crowley’s Ridge) between April 15 and September 15 and buffers of 2,4

- D applicatio ns from susceptible crops in the remaining counties ( Arkansas State Plant Board, 2007 )

. Applications of glyphosate were limited to wind speeds no higher than 10 mph or 15 mph if using a commercially available hooded sprayer ( Arkansas State Plant Board, 2007 )

.
C u rr e nt l y , th e r e a r e 18 st a t e s with some t y pe of re st r i c t ion on the use of 2,4

- D (Figure 7

- 2 and Table 7

- 1)

. T y p e s o f use re st r i c tions on r e g ist ere d p r odu c ts in c lude g e n e r al restricted use pesticide ( R UP ) r e g ul a tions, f o r mul a tion

- sp ec i f ic re st r i c tions, tim e

- sp ec i f ic re st r i c tions a nd/or lo ca tion

- sp ec i f ic re st r i c tions.

T y p e s of S t a t e R e s tr i c t i o n s
2,4

- D p r od u c ts designated as a R UP

– Four states, M a ss ac hus e tts, N e w J er s e y , N e w M e x i co

a nd V er mont have designated 2,4

- D products a RUP. The R UP d e si g n a tion m e a ns th a t

a ppli ca to r s must be cer ti f i e d to use the R UP p r odu c t or h a v e a li ce n s e d a ppli ca tor within the vi c ini t y of the p er son m a k i ng the a ppli ca tion. The a ppli ca tor must a lso k ee p sp r a y rec o r ds.

Page 7

- 9Figure 7

- 2

. States with r estrictions on the use of 2,4

- D Source: ( DAS, 2013 )

.

Table 7

- 1

. S tat e 2 , 4

- D R e s t r i c ti o n s *

TY PE O F R E S T R I C T IO N S TA TE S tate R UP d e si gn at i o n , bu t with n o s p ra y / u se r e strict i o n s ( e .g . li c e n sed

a pp li ca to r s, p e r mi t ti ng , r e c o r d k ee p i ng , e t c .) M A
, NJ
, N M
, V T

S tate R UP d e si gn at i o n a n d s p ra y/ u s e r e s trict i o n s C A
, L A
, T X
, WA N o st a te R UP d e si gn at i o n b u t s p ra y / u se r e strict i o n s AR, FL, ID, IA, MI, MS, NY, OH, OK, OR

T o t a l nu m be r o f s t a t e s 18

* S t a t e r e gu l a tio n s s ub je c t t o chang e. Source: ( DAS, 2013 )

2,4

- D p r odu c ts designated a s a R U P a long with sp r a y u s e r e st r i c tions

– Four states, C a li f o r ni a , L ouisi a n a , T e x a s a nd W a shin g ton designate 2,4

- D as a RUP and in addition impose spray use restrictions which v a r y b y st a t e

. I n th e se st a t e s, a ppli ca tions ar e re st r i c t e d or
p r ohibit e d du r ing c e r t a in tim e s of the y ea r (e

. g . Ap r il th r o u g h S e pt e mb er ) in d e s i g n a t e d c ou n ti e s. F or the r e m a ining c ounti e s in L ouisi a n a a nd T e x a s, bu ffer s fr om s e nsitive or sus ce ptible cr ops

a r e e s t a blish e d.

2,4

- D products are subject to sp ec i f ic sp r a y u se re st r i c tions

– Ten states, A r k a ns a s, I d a ho, I o w a , F lo r id a , Mi c hig a n, Mississippi, N e w Yo r k, Ohio, O kl a homa a nd O r e g on impose spray use restrictions though they do not designate 2,4

- D as a RUP. The re st r i c tions r a n g e f r o m bu ffer s to

a er i a l v e r sus g r ound spray a ppli ca tions to the t y p e of 2,4

- D f o r mul a tions which can be applied. F or e x a m p l e , N e w Y o r k h a s sp r a y u se re st r i c tions in on l y th r e e c ounti e s. In these counties, no 2, 4

- D ca n be a ppli e d within 100 fee t of a n y g ra p e vin e y a r d a nd t h er e is a 2

- mi l e bu ff e r f or a ll
Page 7

- 10e st e r f o r mul a tions. I n Mississippi, 2,4

- D is limit e d to g r ound spray a ppli ca tions on l y fr om Ap r il 1 to S e pt e mb e r 30. I n I o w a , e st e r f o r mul a tions on l y a r e p r ohibit e d in f ive c ou n ti e s. The specific state restrictions of 2,4

- D use are summarized in Table 7

- 2.

Table 7

- 2

. Summary of State R estrictions on the U se of 2,4

- D

S T A TE RUP RE S TRICTIO N S

A r ka n sas No A l l 2
, 4

- D herbicides a r e i n C l a s s F w i t h u s e r e s t r i c t i on s

. From A p r

. 15

- S e p t. 1 5: 2,4

- D u s e is not allowed i n C l a y , Gr ee n e, C r a i g hea d

, P o i n s ett, C r o ss , C r i t t end e n, S t. Fr an c i s , L e e, P h i l l i p s , and M i ss i ss i p p i C oun t i e s

. P e r m i ts m ay be obt a i n e d to a l l o w

e x e m pt i o n w i t h k e y r e q u i r e m ents r e c o r d i n g ap p li c a t i on de t a i l s

. B u ff er z one / w i n d s pe e d r e q u i r e m ent s

. B u ff er z o n es s et: e .g. 4

m il e a e r i a l ; 1 m il e g r ou n d. A R Re g u l at i o ns on P e s t i ci de C l a ss i f

i c a t i on

- F i nal Ru l e ( Re v

. 06/ 0 7 ) :

Cali fo r n ia Y es RUP f or p r o d u c ts 1 g al or g r eater c on t a i n i n g o v er 15% a c t i v e i ng r e d i ent. Permits are needed to spray 2,4

- D in de f i n e d a r eas o f S a cr a m ento, M a de r a, Fr e s no, Ki n g s , T u l a r e, K e r n , and Sa n J oa q u i n Coun t i e s

. R e s t r i c t i o ns are b a s ed on da t e s , f

o r m u l at i on t y p e, w i n d s p ee d, s e t

- ba c k f r o m c o m m e r c i al

v i n e y a r d or c otton p l a nt i ng. 2,4

- D u s e r e s t r i c t i ons exist t o p r o te c t the California Red Legged Frog ( bu ff er z o n es i n 3 3

c o u nt i e s) ; 2,4

- D s a l ts and e s te r s are de si gna t ed as t o x i c a i r

c onta m i nant s

. Ti t l e 3, C CR 3, S e c

. 6 4 00

Florida No S a l e a nd u s e of h i g h l y v o l at i l e 1 f o r m s of o r gano

- au x i n he r b i c i de s i s p r o h i b i t e d e xc ept f or tho s e p r o du c ts l a be l ed as plant growth regulators on c i t r u s

. M i n i m u m s e t

- ba c k d i s tan c es f r o m

s u sc e pt i b l e cr o ps a r e s pe c i f i e d ba s e d o n w i n d s pe e d. M ax w i nd

s p eed = 1 0 m ph. A p p li c a t or r e c o r d k eep i ng r eq u i r e m ents are in effect. A e r i al a p p l i c at i on b y f i x ed

- w i ng a i rcr a f t is p r o h i b i t e d J an 1 un t i l M a y 1 i n H e n d r y , P a l m B ea c h, G l a de s , M a r t i n

c o u nt i e s

. F l o r i da A d m i n i s t r at i v e Co d e Ch a pter 5 E

- 2

. 033 ( f f )

I d a h o No 2,4

- D e s ter r e s t r i c t i o ns exist in L a tah, N e z P e rc e , and C l e a r w a t er Coun t i e s

. Re s t r i c t i ons are b a s ed o n ae r i a l or g r o un d application

, f

o r m u l at i on t y p e, s et

- ba c k f r o m s u s c ept i b l e c r op, and w i nd

s p ee d

. B u ff e r s f r o m ha z a r d a r eas required f or 2,4

- D a m i nes a n d

a c i d s , MC P A
, MC P B
, and d i c a m ba. ID A P A 02. 0 3. 0 3 S e c

. 5 5 0

I o w a No T he u s e of h i g h v o l at i l e e s te r s 2 f o r m u l at i ons of 2

, 4

- D a nd 2
, 4,5

- T
, the a l c o h ol f r a c t i o n of w h i c h c o nta i ns f iv e or f ewer c a r bon s , is
p r oh i b i t ed i n t he c o un t i es of Ha rr i s on, M i ll s , Le e , Mu s c at i n e a nd
t hat pa r t of P o tt a watta m i e c ou nt y we s t of Ran g e 41 W e s t of the 5th P .M. 2 1

— 45

. 27 ( 2 06)

Louisiana Y es 2,4

- D is designated an RUP f or agricultural u s es. Re s t r i c t i o ns f or

c o m m e rc i al and p ri v ate ap p li c a t o r s are ba s ed on t i m i n g , l o c a t i o n, and w i nd s p ee d

. 32 pa r i s hes have r e s t r i c t i on s

. LA T i t l e 7, P a r t XX I

II, § 1 1 03

Page 7

- 11S T A TE RUP RE S TRICTIO N S

M assac hu se tt s Y es If p r odu c t c ont a i ns > 2 0% 2
, 4

- D, i t i s a S t ate RUP

- - a p p li c at i o n must be m ade b y c e r t i f i ed a p p li c a t o r s and there are r epo r t i ng

r e qu i r e m ent s

. 3 3 3 C M

R 1. 0 0

M ic h i g an No No u s e of v o l at i l e e s ter f o r m s of 2, 4

- D and M C P A are allowed

w i t h i n s p e c i f i ed r eg i o ns f r o m M a y 1 to Oc t. 1 i n pa r ts of B e rr i en, Ca ss , K a l a m a z oo and V an B u r en c o un t i e s

. There are s p r a y er

s p e c i f i c at i ons f or a m i ne f o r m s

. MDA Reg 28 5 .6 3 7

M ississi pp i No For ho r m one

- t y pe he r b i c i d es, 3 r e s t r i c t i ons apply f or ae ri al
ap p li c a t i on. Restrictions are based on da t e and type of aircraft and include n o use of e s ter f o r m u l at i o n s, a 0.5 m il e

s e t

- ba c k f r o m c otton and s u sc ep t i b l e cr op s , applications at w i nd

s peed < 5 m ph. There are a p p li c a tor and li c e n s i ng r eq u i r e m ents. M i ss. Code A n n. § 69

- 2 1

- 109 ( P a r t 3

- Ch 1 0

- S u b 01) New Je r s e y Y es Concentrated 2,4

- D ( > 2 0 %) may only be pu rc ha s ed and u s ed b y

c e r t i f i e d ap p li c a t o r s N. J

. A .C. 7: 3 0

- 2

. 10

New M exico Y es State restrictions apply to all 2,4

- D products used in agriculture. S p r a y r e s t r i c t i ons i n C u r r y and R oo s e v e l t c o u nt i es are ba s ed on t i m i ng, a p p li c a t i on m ethod, and must be applied at windspreeds < 1 0 m ph and only by ce r t i f i e d a p p l i c ato rs

. Permits are required f or ap p li c a t i ons of l o w v o l a t i l e formulations. Esters and ae r i al

a p p l i c a t i ons are not permitted i n the s e 2 c o u nt i es from A p r .15 t o Oc t. 1. 21. 1 7.56 N M

A C

New Y o r k No For 2,4

- D, 2 ,4

- 5 T
, and MCP s p r a y r e s t r i c t i ons and s e t

- ba c k s of 100 f t f r om g r ape v i n e y a r ds i n po r t i ons of Chau t au q ua, E r i e , N i a g a r a c oun t i e s are in effect

.

NY E CL A r t. 3 3 § 321

- 324
Oh io No Re s t r i c t i o n f r om u s e of e s t e r f o r m u l at i on i n Ma d i s on t o wn s h i p of La k e Coun t y is in effect

. O R C T i t l e IX

, Ch. 921

O kla ho ma No A p p li c a t i ons of p r o du c ts c onta i n i ng 2 ,4

- D e s t e r s or d i c a m ba to

a g r i c u l t u r al l a n d s are prohibited i n Gr ee r , H a r m on, and K i o w a

c ou n t i es M a y 1

- Oc tober 1 5; A p p li c a t i o ns of p r odu c ts c o nta i n i ng 2 ,4

- D, d i c a m ba, p ic l o r a m , t r i c l o p y r , or cl o p y r a l i d are prohibited i n J a c k s on and T ill m an c ount i es M a y 1

- Oc tobe r

. Not i f i c a t i on and r epo r t i n g p r o c edu r es are required for 2,4

- D applications. 2 O

. S

. § 3

- 8 4 ( 3 5 :30

- 1 7

- 24.1)

O r e go n No Use of h i gh v o l a t il e e s te r s of 2, 4

- D i n a r e as of Mo rr o w a nd U m at ill a c o un t i e s are prohibited A pr 1

- S e pt 1 e xc ept b y p e r m i t.

O

A R 6 0 3

- 0 5 7

- 03 0 1 to 0 32 0

Page 7

- 12S T A TE RUP RE S TRICTIO N S

T exas Y es Use of 2,4

- D, M C PA
, d i c a m ba, q u i n c l o r a c is prohibited within 4 miles of a susceptible crop in 53 " P e s t i c i d e Reg u l a t ed H e r b i ci de C o u nt i e s "

. No ap p li c at i o ns are permitted when w i nd speeds exceed 10 m ph. A d d i t i o n al p r o v i s i ons are s et c o un t y

- b y

c o un t y. T A C 4

- 1

- 7

- E § 7.5 0

, 53

V e r mon t Y es C l a s s A r e s t r i c t ed u s e, application requirements, and reporting requirments are in effect. 6 V

. S

. A

. C h 87

W as h i ngto n Y es A l l p h e n o x y h o r m one

- t y pe he r b i c i des are r e s t r i c t ed t h r oug h out

ea s te r n W a s h i ngton w i t h a dd i t i o nal r e s t r i c t i o ns i n 14 c oun t i e s : A da m s , B ent o n, C o l u m b i a, Dou g l a s /C h e l an, Fr a n k li n, G a r f i e l d, Gr ant, K i t t i ta s , K l i c k i tat, L i n c o l n, O k anog a n, S po k ane, W a ll a W a ll a, W h i t m an, and Y a k i m a. S pe c i f i c r e s t r i c tions are determined b y c oun t y pertaining to b ou n da ri es; f o r m u l at i o n t y pe,

a p p l i c at i on pa r a m ete rs , date s , and a e r i a l or g r ou n d, s e t

- b a c k s

. 16 W

A C 1 6

- 228

, 232
Source: ( DAS, 2013 )

1 Al l p e s t i ci d e s r e g i s te r e d f or s a l e i n A r k an s as a r e a ss i gn e d t o a C l a ss

. E a c h C l a s s c a rr ie s w it h i t one or

m o r e r e s t r ic t i ons t hat m u s t b e c o m p l ie d w i t h by t h e u s e r , app l ic a t o r , or d e a le r

. T he cl a ss if i c a t i on s y s t e m

r

ang e s f r om C l a s s A wh i c h p res u m ab l y a l l p e s t i ci d e s a r e r e g i s te r e d as i n i t i a l l y , un t i l a p r o b le m d ev e l op s

. T

he o n l y u s e

- r e s t r icti ons a ss i g n e d t o C l a s s A p r odu ct s a r e t ho s e on t h e p r odu c t l a b e l . If p r ob le m s d e v e l op

w i t h a p r odu ct , t

he P l ant B oa r d, a fte r a p u b l i c h e a r i ng, c a n m o v e a p r odu c t f r om t h e C l a s s A d e s i g na ti on t o ano t h e r d e s i gn a t i on ( B , C, D

, E or F ) wh i c h has m o r e r e s t r i ct i on s

. E a c h cl a ss i f

ic a ti on c a rr ie s w it h i t

a l l t h e r e s t r i cti on( s ) t hat a r e s p eci f

ie d f or t h a t cl a s s p l u s a l l t h a t c a m e b ef o r

e it

.

2 N ote: H i g h vol a tility est e r s of 2

, 4

- D ar e t ho se t ha t h a ve five o r f e w e r ca r bon s on t h e a l c o ho l si d e cha i n. C u rr e n tly t h e r e a r e n o h i g h vol a tility es t e r s r e g ist e r ed f or u se in t h e U n i ted S t a tes.

3 H o r

mo n e

- ty p e h e r b i c i d es i nc l ud e 2

, 4

- D

, 2

, 4

- D B, a mi nop y r a li d

, c lo p y r a li d

, d i ca m ba

, d i ch lo r p r o p, fl u r oxy p y r , M C P

A

, M C P

B, me c o p r o p , p i c lo r a m, qu i nc lo r a c an d t r i c lo p

y r

.
Ne w t ec hnologi e s f or c o ntroll i ng dri f t and v ola ti lity ( DAS, 2013 )

DA S c ondu c t e d a n e x t e nsive e v a lu a tion of v a r ious s a lts und e r c onditions indu c ing h i g h vol a tili t y to id e nti f y c a ndid a t e s th a t h a d si g ni f i c a nt l y r e du ce d vol a tili t y a nd thus lo w e re d pot e nti a l f or inju r y to sus ce ptible pl a n ts. T he re sults l e d to the d e v e lopm e nt of 2,4

- D c h oline s a lt. T his nov e l f

o r m of 2,4

- D h a s b ee n t e st e d in the l a bo ra to r y a n d subs e qu e nt l y in f i e ld s t udi e s. Q u a nti f i ca tion of vol a tili z e d 2,4

- D fr om s o y b e a n a nd b ar e soil f i e lds d e monst ra t e d that 2,4

- D e t h y lh e x y l e st e r

w as the most vol a til e , w ith ca l c ul a t e d loss ra t e s of the 2,4

- D e t h y lh e x y l e st e r a s mu c h a s t w o

o r d e r s of m a g nitude g r ea t e r th a n t he 2,4

- D dim e t h y l a mine (D M A ) f o r m, w hi c h is c onsid ere d to be much less volatile than ester formulations ( National Pesticide Information Center )

. T he

c holine f o r m of 2,4

- D m ea su re d a s mu c h a s 50 X l e ss vol a tili t y t h a n the D MA f o r m a nd h a d d ra m a ti ca l l y l e ss inju r y to a v ar i e t y of cr ops kno w n to be s e nsitive to a u x in h er bi c id e s und e r

c on f in e d c onditions a s c o mp are d to e st e r a nd a mi n e f o r ms of 2,4

- D ( US

- EPA, 2013 )

.

Page 7

- 13DA S ’ s n e w p r od u c t c on t a ining 2,4

- D c holine a nd g l y phos a te D MA (E nlist D uo TM h er bi c id e ) w ill

m a ke the h er b i c ide sp r a y d r opl e ts l a r g e r a nd mo r e uni f o r m in si z e c omp ar e d to a st a nd ar d 2,4

- D

a nd g l y pho s a te t a nk mix a ppli ca tion. DA S h a s m e a su re d a 3 X imp r ov e m e n t (re du c tion) in d r i f t a ble f in e s ( < 150 μ) f or both 2,4

- D c holine a n d g l y phos a te un d e r f i e ld c onditions using

c omm erc i a l a ppli c a tion e quipm e nt. T his v a lid a t e s obs er v a tions m a de und e r c ont r oll e d l a bo ra to r y

a nd w ind tunn e l c onditions. Coupl e d w ith using the l a t e st in d r i f t re d u c tion no zz l e s, a s mu c h a s a 10X re du c tion in d r i f t w a s ac hi e v e d c omp a r e d to a st a nd ar d t a nk mix a ppli ca tion of the s a me

ac tive i n g re di e nts usi n g c onv e ntion a l no zz l e s.

P e nding re g ist ra tion b y E P A
, DA S int e nds to m ar k e t E nlist D uo TM Her bi c ide w ith Col e x

- D Tec hnol og y , a p r e

- mix of the n e w 2,4

- D c holine s a lt a nd g l y phos a te dim e t h y l a mine w ith r e du ce d d r i f t a nd vol a tili t y c h a r ac t er isti c s, f or use w ith Enlist TM corn and soybean

. V i a a T e c hnolo g y U se A g ree m e nt, D A S w ill r e qui r e g r o w e r s of Enlist TM corn and s o y b ea n w ho c ho o se to use 2,4

- D in post

- pl a nt a ppli ca tions to pu rc h a se t h e 2,4

- D f o r mul a tion in E nlist D uo TM to p r ovide this a dd e d
p r ot ec tion a g a inst o f f

- t a r g e t e x posu re

. A c ombin a tion of E P A

- re qui r e d l a b e l re st r i c tions,

c ont rac tu a l obl i g a tions a nd g r o we r e du ca tion a nd out reac h are expected to minimi z e o f f

- t a r g e t

e f

fec ts to n e i g hbo r i n g cr ops when a ppli c a tions of E nlist D uo TM is made to Enlist TM corn and

s o y b e a ns.

I n a ddition to the t ec hnolo g y innov a tions, the h e r b i c ide p r odu c t l a b e l a nd p r odu c t use g uide do
not a llow a ppli ca tions into area s w h er e t e m p e r a tu r e inv er sions a r e p r e s e nt, do not a llow

a ppli ca tions wh e n winds e x cee d 15 mph, do not a llow aer i a l a ppli c a tions, a nd re qui r e use of on l y sp r a y no zz l e s th a t p r odu c e a c o a r se or c o ar s e r sp r a y d r opl e t si z e

. S u c h st e w ar dship a nd

re sponsible use r e qui re m e nts are expected to f u r th e r minim i z e the pot e nti a l f or o ff

- t a r g e t h er bi c ide mov e m e nt.
In addition to the reduction of particle drift or volatilization due to physical properties of the herbicide formulation , other precautions have been included in conjunction with the Enlist TM Weed Control System to minimize the potential for off

- target movement . Specifically, DAS will request an amendment to its pending herbicide label submitted to EPA to include language regarding sensitive crops under a new “Susceptible Plants” heading on the label and label language requiring buffer zones between areas of 2,4

- D choline use and sensitive plants ( Coalition, 2012 ) . The proposed label for Enlist Duo TM Herbicide with Colex

- D Technology TM label does not allow herbicide application through any type of irrigation equipment and prohibits aer ial application ( DAS, 2011 ) . Individual state regulations for use of 2,4

- D, such as the widesprea d prohibition of aerial application and restricted seasonal application, will also remain in effect. For instance, Texas has limited the application of “regulated herbicides” (such as 2,4

- D) by county with the aerial application of 2,4

- D being prohibited in many counties between March 10 and September 15 or outright prohibited within a given distance of any susceptible crop ( 4 Tex. Admin. Code §7.53 )

. Iowa state law prohibits the use of some 2,4

- D esters in some counties ( 21 IAC 45.27 [ 2013 ] ). Mississipp i prohibits the aerial application of 2,4

- D by fixed wing aircraft between April 1 and September 30 (CMSR 02

- 001

- 310). However, Mississippi allows 2,4

- D to be applied by helicopter between April 1 and September 30 as long as certain application criteria a re met , such as the use of precision spray systems, the use of booms no longer than rotor diameter, a flight speed of no more than 30 mph during application, and wind speed of 5 mph or less at the time of application (CMSR 02

- 001

- 310).

Page 7

- 14Use of the innov a tiv e c h oline s a lt of 2,4

- D, the n e w f o r mul a tion t ec hnol o g i e s, a nd Dow Ag r o S c i e n ce s ’ S t e w ar d s hip P r o g ra m is expected to h e lp r e du c e the pot e nti a l f o r o f f

- t a r g e t imp ac ts on s e nsitive cr ops a nd non

- c r op pl a nts/o r g a nisms.

P ropos e d H e rbi c ide L ab e l L anguage f or Enl i st D u o TM ( DAS, 2013 )

DA S h a s submitt e d to E P A f or a p p r ov a l a p r opo s e d l a b e l f or its E nlist D uo TM her bi c ide w ith Col e x

- D Tec hnolo g y TM , a p re

- mix of the n e w 2,4

- D c holine s a lt a nd g l y pho s a te D M A

. DA S ’ s p r opo s e d l a b e l c ont a ins the inst r u c tions f or use di rec t l y a d d re ssing t h e pot e nti a l f or s p r a y d r i f t

a nd vol a tili t y

. T h e s a me l a b e l inst r u c tions w ill be su b mitt e d f or use on E nlist TM s o y b e a ns.

DA S h a s submitt e d f or E PA a pp r ov a l the f ollo w i n g proposed E nlist D uoTM l a b e l l a n g u a g e

s p ec i f i c a l l y a dd re ssi n g sp r a y d r i f t m a n a g e m e nt. D u r i n g its l a b e l a pp r ov a l p r o ce ss, E PA m a y impose a dditio n a l use re st r i c tions or oth e r p r ot ec tive m ea su re s f or c o r n a nd/or s o y b ea n

. Sp r ay Dr i f t M anag em e nt

A void d r i f t

. U se e x tr e m e c a r e w h e n ap p lying t h is p r odu c t t o p re v e nt in j u r y t o d e si r able plan t s

a n d cr ops.

D o not a llow G F

- 2726 to mist, d r ip, d r i f t or spl a sh onto d e si ra ble v e g e t a tion sin c e minute
qu a ntiti e s of this p r odu c t ca n c a use s e v er e d a m a g e or d e st r u c tion to the cr o p, pl a nts or oth e r

a r ea s on w hi c h t r e a tm e nt wa s not int e nd e d. T he lik e lihood of inju r y o cc u rr i n g f r om the use of this p r odu c t i n crea s e s w h e n w inds ar e gus t y , a s w ind v e l o c i t y in c rea s e s, w h e n w ind di rec tion is

c onst a n t l y c h a n g i n g or w h e n th e r e a r e oth e r m e t e o r ol o g i c a l c onditions th a t fa vor sp r a y d r i f t. W h e n sp r a y i n g , a void c omb i n a tions of p re ssu r e a nd n o zz le t y pe th a t w ill re sult in f ine p a r ti c l e s ( mist) w hi c h ar e li k e l y to d r i f t. D o not apply at e x ce ssive sp ee d or p re ssu re

. U se of this
p r odu c t in a n y m a nn e r not c onsist e nt w ith this l a b e l m a y re sult in inju r y to p er son s , a nim a ls or

cr ops, or ot h e r unint e nd e d c on s e qu e n ce s.

A voiding sp r a y d r i f t a t t h e a ppli ca tion site is the r e sponsibili t y of the a ppli c a to r

. T he int erac tion of m a n y e quipm e nt

- a nd

- w ea th e r

- re l a t e d fac t o r s d e t er min e s the pot e nti a l f or sp r a y d r i f t. T he

a ppli ca t o r a nd the g r o w e r a r e r e s p onsible f or c onsid er i n g a l l th e se fac to r s w h e n m a ki n g d ec isions.

D o not a er ially apply t h is p r odu ct

.

Dr opl e t Si ze

A pp l y a s a c o ar se or v e r y c o ar se s p r a y ( A S A B E S

- 572 St a nd ar d )

. U se d r i f t re du c i n g no zz le ti p s in acc o r d a n c e w ith m a nu fac tu r e r di r e c t ions th a t p r odu c e a d r op l e t c l a ssi f i ca tion of c o ar se o r v e r y

c o ar se to s i g ni f i ca nt l y re d u c e the pot e nti a l f or d r i f t.

G r oundboom A ppli c a t ion

U se the minimum boom h e i g ht b a s e d upon the n o zz le m a nu fac tu rer’ s di r e c tions. Sp r a y d r i f t pot e nti a l in crea s e s a s boom h e i g ht in c r ea s e s. Sp r a y d r i f t ca n b e minimi z e d if no z z le h e i g ht is not g r e a t e r th a n the m a x imum h e i g ht sp ec i f i e d b y the no zz le m a nu fac tu r e r f or the no zz le s e l ec t e d.

Page 7

- 15Wind

Dr i f t pot e nti a l is lo we st a t w ind sp ee ds of 10 mph or l e ss. H o we v er , m a n y f ac to r s, in c luding d r opl e t si z e a n d e quipm e nt t y p e , d e t er m ine d r i f t pot e nti a l a t a n y g iv e n sp e e d. D o not a pp l y a t

w ind sp e e ds g rea t e r th a n 15 mph. N o te : L o c a l t er r a in ca n i n f lu e n c e w ind p a tt er ns. T he

a ppli c a tor s hould be fa mili a r w ith lo ca l w ind p a tt er ns a nd h o w th e y af f

ec t d r i f t.

T e m p e r a t u r e and Hu m idi t y

W h e n m a king a ppli c a tions in low re l a tive humidi t y , s e t up e quipm e nt to p r odu c e l a r g e r d r opl e ts to c omp e ns a te f or e v a po r a tion. Dr opl e t e v a po ra tion is most s e v e r e w h e n c onditions ar e both hot

a nd d r y

.

T e m p e r a t u r e Inv er sions

I f a pp l y i n g a t w ind sp ee d s l e ss th a n 3 mph, the a ppli ca tor must d e t er mine i f : a ) c onditions of
t e mp era tu r e inv er sion e x ist, or b) st a ble a tmosph er ic c onditions e x ist a t or b e low no zz le h e i g ht. D o not m a ke a ppli ca tions d u r ing a t e mp e r a tu r e inv e r sion or st a ble a tmosph er ic c onditions. Te mp era tu r e inv er sions r e st r i c t v er ti ca l a ir mi x in g , w hi c h ca us e s sm a ll susp e nd e d d r opl e ts to

re m a in in a c on c e nt ra t e d c loud. T his c loud ca n move in unp re di c t a ble di r ec tions due to the li g ht

v ar i a ble w inds c ommon du r ing i n v er sions. Te mp era tu r e inv er sions a r e c h a r a c t er i z e d b y in cr e a sing t e mp e ra tu r e s w ith a ltitude a nd ar e c ommon on ni g hts w ith limit e d c loud c ov e r a nd l i g ht to no w ind. T h e y b e gin to f o r m a s the sun s e ts a nd o f t e n c o ntinue into the mo r nin g

. T h e ir
p re s e n c e ca n b e indi ca t e d b y g r ound f o g ; ho we v e r , if f og is not p re s e nt, the p re s e n c e of a n inv er sion c a n a lso be id e nti f i e d b y the mo v e m e nt of smoke fr om a g r o u nd sou rce . Smoke th a t l a y er s a nd mov e s l a t era l l y in a c on n ec t e d c loud ( un d e r low w ind c onditions) indi ca t e s a n inv er sion, w hile smoke th a t mov e s up war ds a nd ra pid l y dissip a t e s indi ca t e s g ood v er t i ca l a ir mixin g

.

Dr i f t S et ba c ks f r om S e nsi t ive Are as

A llow s e tb ac ks ( bu f fe r z on e s) up w ind of s e nsiti v e ar e a ( e

. g ., re sid e nti a l ar ea s, bodi e s of wa t er , kno w n h a bit a t f or th rea t e n e d o r e n d a n g e r e d sp ec i e s, s e nsitive non

- t a r g e t cr ops oth e r th a n those list e d a b ov e ).

I f a c o ar se o r v e r y c o ar s e d r opl e t c l a ssi f i ca tion ca nnot be m a int a in e d, a n u p w ind s e tb ac k of 250 fee t f r om s e nsitive ar e a s must be obs er v e d

. Applicators will not exceed a spray volume of 15 gallons (water) per acre.

In addition, when sensitive areas are nearby, applicators will use recommended drift setbacks based on wind speed and spray boom hei ght above canopy (see below).

Page 7

- 16Table 7

- 3

. Drift Setback Distances (feet)

Sus ce p t ible P lan t s

D o not a pp l y un d e r c i r c u mst a n ce s w h e r e sp r a y d r i f t m a y o cc ur to f ood, f o r a g e , or oth e r pl a ntin g s th a t m i g h t be d a m a g e d or cr ops t h ere of re nd e re d un f it f o r s a l e , use or c onsumption. A void

c ont ac t of h er b i c ide w ith f oli a g e , g ree n s t e ms, e x pos e d non

- w oo d y r oots of c r o p s, d e si ra ble pl a nts a nd t re e s b eca u s e s e v e r e inju r y or d e st r u c tion m a y re sult. Sm a ll a mounts of sp r a y d r i f t th a t

m a y not be visible m a y inju r e sus ce ptible b r o a d l ea f pl a nts. B ef o r e m a ki n g a n a ppli ca tion, pl ea s e

r efe r to y o ur st a t e’ s s e nsitive cr o p r e g ist r y ( if a v a il a bl e ) to id e nti f y a n y c omm e r c i a l sp ec i a l t y o r

c er ti f i e d o r g a nic cr ops th a t m a y b e l o ca t e d n e ar b y

.
Comm erc i a l l y g r o w n tom a to e s a nd oth e r f r uiting v e g e t a bl e s (E PA cr op g r oup 8 )
, c u c u r bits (E PA

c r op g r o up 9 )
, a nd g ra p e s a r e p a r ti c ul ar l y s e nsitive to d r i f t fr om this p r odu c t. D o not a pp l y w h e n

w ind di rec tion f a vo r s o ff

- t a r g e t mov e m e nt o n to th e se cr ops.

S t a t e and Lo c al Re qui r e m e n t s

A ppli ca to r s must f ollow a ll st a te a nd lo ca l p e sti c i de d r i f t re qui r e m e nts r e g ar ding a ppli ca tion of 2,4

- D h er b i c id e s. W h er e st a t e s h a v e mo r e st r ing e nt r e g ul a ti o ns, th e y must be obs er v e d.

T he submitt e d E nlist D uo TM l a b e l l a n g u a g e a lso re q ui re s a ddition a l m ea su r e s to a void o ff

- t ar g e t

mov e m e nt a nd cr o p inju r y , in c ludi n g d e t a i l e d inst r u c tions f or c l e a n

- out of sp r a y e r e quipm e nt,

use of d r i f t c ont r ol a dditiv e s, a nd boom a nd no zz le h e i g ht inst r u c tions.

Addition a l D AS m e asu r e s to addr e ss spray dri f t and v olatility

A s not e d a bov e , D A S w ill c ont rac tu a l l y re qui r e g r o wer s of Enlist TM corn and soybean w ho w ish to use 2,4

- D a s a n in

- cr op h e r b i c ide to use on l y E nlist D uo TM

. T his n e w 2,4

- D t e c h n olo g y w ill
p r ovide subst a nti a l l y lo we r vol a t i li t y t h a n a n y oth e r f o r m of 2,4

- D
, a s w e ll a s imp r ov e d d r i f t

c ont r ol, low odo r , a nd imp r ov e d h a n d ling c h a rac t er isti c s.

T h r ou g h its T e c hnol og y U se A g r e e m e nt, DA S w i ll impose a l e g a l a nd c o n t rac tu a l oblig a tion th a t

w ill re qui r e a ll g r o w er s o f Enlist TM corn and s o y b e a n to: Wind Speed (mph) Spray Boom < 24 inches above Canopy Spray Boom >24 inches above Canopy

<5 15 `30

5

– 10 40 80

10

– 15 80 150

Page 7

- 17U se on l y E PA ac c e pt e d a nd DA S a utho r i z e d 2,4

- D f o r mul a tions c ont a ining Col e x

- D Tec hnol og y TM , su c h a s E nl i st D uo TM

, f or in

- cr op a ppli c a tions to Enlist TM corn and s o y b e a n.

R ea d a nd f ollow F I F RA P e sti c ide P r odu c t L a b e l di rec tions.

R ea d a nd f ollow the E nl i st TM W ee d Cont r ol S y st e m P r odu c t U se G uid e

.
U se p r op e r l y m a int a in e d a nd ca lib ra t e d g r ound a p pli ca tion e quipm e nt f or E nlist D uo TM with Col e x

- D Tec hnology TM w ith minimum boom h e i g hts.

U se no zz l e s th a t re du c e t he pot e nti a l f or p h y si ca l d r i f t of E nlist D uo TM w ith Col e x

- D Tec hnol og y TM

.

F ollow inst r u c tions f or e quipm e nt c l ea n

- out a f t e r p r odu c t us e

.
DA S w ill p r ovide c omp r e h e nsive t ra ini n g on its t ec hnol og y a nd po r t f olio of p r odu c ts to g r o w e r s, d ea l er s a nd dist r ibuto r s th r ou g h a v ar i e t y o f f o r m a ts. E du ca tion a nd t ra ini n g , r e in f o r c e d th r o u g h
p r odu c t p r o f il e s, t e c hni c a l bull e tins, s a l e s lit era tu re , di rec t m a ili n g a nd w e b sit e s w ill a lso be
p re s e nt e d in multiple f o r m a ts to e nh a n c e l e ar ni n g a nd m a st e r y of c o r e c on c e pts re l a t e d to
st ewar dship to be e mpl o y e d ar ound Enlist TM corn and soybean . A v a r i e t y of e du ca tion a l f o r m a ts

w ill be us e d to p r omote c o n c e pt l ear nin g

. T his t ra ining w ill in c lude e du ca tion on sp r a y t ec hnol og y a nd h er bi c ide a ppli ca tio n , in c luding sp r a y q u a li t y b a si c s, a s we ll a s sp r a y q u a li t y of E nlist D uo TM

, a s we ll a s how to minimi z e the pot e nti a l f or o ff

- t a r g e t mov e m e nt of E nlist D uo TM

. Producers who do not comply with the requirements of the stewardship program risk losing access to the EnlistTM Weed Control System. Legal penalties may also be imposed by state regulatory agencies when label instructions are not followed.

P ot e ntial O ff

- targ e t P e sti c ide I m pa c ts on O rg a nic C rops ( DAS, 2013 )

Gr o wer s o f o r g a n i c cr ops m a y a lso fa c e e c onomic d a m a g e s fr om o ff

- t ar g e t p e sti c ide mov e m e nt,

e v e n if th e ir cr ops a r e n o t d a m a g e d. I f a c er ti f y i n g a g e nt t e sts a cr op g r o w n und e r o r g a n i c p r odu c tion a nd the t e st r e v ea ls the p re s e n c e o f re s i du e s fr om a p e sti c ide not a pp r ov e d f o r use und e r the Na tion a l Or g a n ic P r o g r a m (NO P ) , the c r op m a y not be sold a s o r g a n i c if the r e sidue is
p re s e nt a t a l e v e l g r e a t e r th a n f ive p e r ce nt of the E PA tol era n c e f or the d e t e c t e d p r ohibit e d

re sidue ( 7 C F R 205.671 )

. A g r o we r w hose o r g a nic cr ops w er e subj e c t to o ff

- t a r g e t p e sti c ide

mov e m e nt th a t re sult e d in re sidue l e v e ls g r ea t e r th a n f ive p e rce nt of t h e E PA tol era n c e c ould th e n lose the o r g a nic p r e mium he m a y oth e r w ise h a ve obt a in e d f o r his cr o p. W hile some

cer ti f y

i n g a g e nts h a ve r e f us e d to a llow o r g a nic p r o du c tion on f i e lds th a t h a v e b ee n the ob j ec ts of
sp r a y d r i f t, a r e c e nt c ou r t d ec ision f ound this th re e y e a r b a n on o r g a nic p r o du c tion f ollo w ing
sp r a y d r i f t to be in c onsis t e nt w ith the NO P ( Anonymous, 2012 )

.

I n f in a li z in g the NO P, U S D A d e s cr ib e d the f ollo w ing in re g ar ds to g r o we r’ s re sponsibiliti e s to p r ot ec t a g a inst c h e mi ca l d r i f t ( 65 F R 80556 ) :

Dr i f t h a s b ee n a di ff i c ult issue f or o r g a n i c p r odu ce r s fr om the b e g inni n g

. O r g a n i c op e r a tions h a ve a l w a y s h a d to w o rr y a bout the po t e nti a l f or d r i f t fr om n e i g hbo r i n g o p era tions, p ar ti c ul a r l y

Page 7

- 18d r i f t of s y nt h e tic c h e mi c a l p e sti c id e s. A s the nu m b e r of o r g a nic f ar ms in c r ea s e s, so do e s the pot e nti a l f or c on f li c t b e t wee n o r g a nic a nd non o r g a nic op e r a tions.

I t h a s a l w a y s b ee n the re sponsibili t y of o r g a nic o p era tions to m a n a g e po t e nti a l c ont ac t of o r g a nic
p r od u c ts w ith oth e r subst a n ce s not a pp r o v e d f or use in o r g a nic p r odu c tion s y st e ms, w h e th e r f r om the nono r g a nic po r tion of a split op era tion or f r om n e i g hbo r i ng f ar ms. T he o r g a nic s y st e m pl a n must outline st e ps th a t a n o r g a nic o p e r a tion w ill t a ke to a void this kind of unint e ntion a l c ont ac t.

W h e n w e ar e c onsid er i n g d r i f t issu e s, it is p ar ti c ul ar l y impo r t a nt to re m e m b e r th a t o r g a n i c st a nd ar ds a r e p r o c e ss b a s e d. C er ti f y

i n g a g e nts a tt e st to the a bili t y o f o r g a n i c op era tions to f ollow

a s e t of p r od u c tion st a nd ar ds a nd p r ac ti ce s t h a t m ee t the re qu i re m e nts of t h e Ac t a nd the

r e g ul a tions.

A ll of the p re v e ntions di s c uss e d a bove ar e a v a il a b l e to o r g a nic g r o wer s a nd m a n y ar e re qui re d b y the N O P a s p ar t of t h e ir o r g a nic p r od u c tion pl a n. Simil ar l y , insu r a n c e a nd l e g a l rec o u r se m a y be

a v a il a ble to o r g a nic g r o wer s w ho lose p r e miums a s a re sult of sp r a y d r i f t.

2,4

- D has an extensive history of safe and effecti v e use. It has been thoroughly reviewed and

rere g istered by all m ajor regulatory agencies in t h e world wit h in the last t e n years. R e cently (April 2012), the EPA denied a petition to cancel the tolerances and registrations for 2,4

- D based

on toxic o lo g ical h azard. The Agency issued a de n ial of that petition, affirming that 2,4

- D posed no unreasonable risk when use d a s directe d ( US

- EPA, 2012b )

. Therefore the impacts to the physical environment are expected to be similar under the No Action a nd Action Alternatives.

O th e r pot e ntial sour ce s of o ff

- targ e t m o ve m e nt ( DAS, 2012b )

Soil L e a c hing

2,4

- D h a s a re l a tiv e l y s h o r t h a l f

- li f e a nd is ra th e r immobile in the soil. I n 3 5 rece nt f i e ld dissip a tion studi e s acr oss the U .S., l e ss th a n 5% of a ppli e d 2 ,4

- D mov e d d o w n war d mo r e th a n 15

c m ( 6 in c h e s )

. T h e a v er a g e lo w e st d e pth d e t e c t e d ra n g e d f r om 6 to 12 in c h e s in soils of the south er n U nit e d St a t e s, a nd 16 to 24 in c h e s in low o r g a nic soils w h e r e g r ea t e r mov e m e nt w ould be e x p ec t e d ( ( Industry Task Force, 2006 ) cited in ( DAS, 2012a ) ). Gr ound wa t e r d e t ec tions of 2,4

- D
, w hi c h ar e v e r y r a r e , a r e l ar g e l y a tt r ibut e d to di rec t int r odu c tion b y misuse or spills a t we ll sit e s ( ( Industry Task Force II, 2013 ) cited in ( DAS, 2012a ) ). P r op e r a ppli ca tion a nd a voiding f illing sp r a y e quipm e nt n e a r w e ll h ea ds ar e st a n d ar d g o o d far mi n g p r a c ti ce s th a t minim i z e the pot e nti a l f or l e a c hing a nd w o r k ef f

ec tiv e l y f or 2,4

- D.

R uno f f The environmental risks of pesticide use are assessed by EPA in the pesticide registration process and are regularly reevaluated by EPA for each pesticide to maintain its registered status under FIFRA. EPA’s process ensures that each registered pesticide continues to meet the highest standards of safety to protect human h ealth and the environment ( DAS, 2012a )

. Both field crop and aquatic application for weed control are registered uses of 2,4

- D ( US

- EPA, 2005c ) . Glyphosate is registered for use on many food and non

- food field crops as well as non

crop areas where total vegetation contro l is desired ( US

- EPA, 1993 ) . Although the registered

Page 7

- 19use of glufosinate is primarily terrestrial ( US

- EPA, 2008 ; Bayer CropScience, 2011 ) , it may be applied to certain confined waters for irrigated crops, such as rice ( US

- EPA, 2002 )

.
As described in ( DA S, 2012a ) , as part of an ecological risk assessment, EPA recently evaluated monitoring data from the USGS NAWQA program to assess the current trend of 2,4

- D concentrations in surface water and groundwater ( US

- EPA, 2013 ) ). 2,4

- D was detected in 47 percent of surface water samples (i.e.

, 434 samples from a total national dataset of 931 samples). The maximum concentrations of 2,4

- D ranged from 0.008 μg/l to 8.7 μg/L. 2 ,4

- D was detected in only 1 percent of the groundwater samples (i.e.

, 12 samples from a total national dataset of 1
, 184 samples). The maximum concentrations of 2,4

- D ranged from 0.008 μg/L to 1.4 μg/L. The reported concentrations for both surface water a nd groundwater are lower than in the previously reported drinking water memorandum ( US

- EPA, 2004 )

.
As described in ( DAS, 2012a )
, 2,4

- D is currently approved by EPA for aquatic applications to control aquatic weeds in food use areas (i.e., rice and fish farms) as well as industrial areas (i.e., drainage sy stems) ( US

- EPA, 2005c )

. When used for aquatic treatments (direct application to water for aquatic vegetation control), 2,4

- D has a half

- life of between 3.2 days and 27.8 days ( US

- EPA, 2005c ) ; t he half

- life of 2,4

- D in aerobic aquatic environments is approximately 45 days , and the half

- life of 2,4

- D esters in normal agricultural soil and natural water s is less than 3 days ( US

- EPA, 2005a ; US

- EPA, 2009 )

. E PA has stated that the 2,4

- D acid and amine salts are practically non

- toxic to freshwater or marine fish ( US

- EPA, 2005c )

. Environmental Loading of Her b icides Used on Corn ( DAS, 2012b ) DAS has conducted an analysis to deter m ine the anticipated impact on env i ron m ental loading of herbicide s resultin g fro m th e us e o f 2,4

- D cho l ine on herbicide tolerant DAS

- 40278

- 9 corn, DAS

- 68416

- 4, soybean, and DAS 44406

- 6 soybean. Specifically, this analysis looked at the environ m ental load of herbicides applied on gl yphosate tolerant corn and soybeans to control glyphosate resistant and hard

- to

- control weed biotypes ( DAS, 2012a )

. The top c u rrently available herbicide progra m s (excluding just increasing the rate of g l yphosate alone) that are currently being recommended to control glyphosate resistant weeds in corn under scenari o s representative of different key corn

- growing regions were co m pa red to projected use of Enlist Duo TM

. W hile the range of rates of these currently available alternate progra m s and the ones for Enlist Duo TM pro g ra m s overlap p ed, when the a v erage of the Enlist Duo TM program rates were

co m p ared to the a v erage of all of these t op alt e rnates, t h e analy s is indicated that the use of 2,4

- D on herbicide tolerant DAS

- 40278

- 9 corn w ould reduce the per acre environ m ental load of herbicides co m pared to these top, currently available, non

- glyphosate alternative progra m s. Reductions on corn ran g ed by 0.15 to 0.74 lb ai/ac, within the individual scenarios, with an overall avera g e reduction of 0.49 lb ai/ac across a ll scenarios ( DAS, 2012a )

.

H erbicide use may increase to meet the need for additional integrated weed management tactics to mitigate herbicide

- resistant weeds in different cropping systems ( Culpepper et al. , 2008 ; Owen, 2008 ; Heap, 2011 ; Owen et al. , 2011 )

. Some of these adjustments may have the potential to impact surface water quality through increased sedimentation and agricultural chemical loading derived from exposed soils ( Towery and Werblow, 2010 ; Owen et al. , 2011 )

. Some of these adjustments have the potential to impact air quality by increased emissions from tillage equipment and release of particulate matter generated from soil disturbance during tillage operations ( Madden et al. , 2009 )

. Increases in herbicide resistant weeds potentially could lead to

Page 7

- 20a decline in no

- till and conservation tillage. Declines in such practices are expected to reduce air quality from greater use of heavy fiel d equipment and greate r release of airborne particles. Implementation of BMP to slow soil erosion and filter pollutants from surface runoff, such as vegetated strips, control of spray drift, and adherence to label restrictions governing safe application a nd equipment cleanup, minimize the potential for pesticide impacts to surface and groundwater.

The environmental risks of pesticide use are assessed by EPA in the pesticide registration process and are regularly reevaluated by EPA for each pesticide to mai ntain its registered status under FIFRA. In this process, steps to reduce pesticide drift and volatilization are included on a pesticide’s label approved by EPA. EPA’s process ensures that each registered pesticide continues to meet the highest standards of safety to protect hum an health and the environment. Use of the herbicides glyphosate 2,4

- D , and glufosinate would be contingent upon periodic reevaluation and continued approval by EPA

.
References:

Johnson v. Paynesville Farmers Unio n Cooperative Oil Company. State of Minnesota Supreme Court 2012. Arkansas State Plant Board.2007. "Final Rule Arkansas Regulations of Pesticide Classification ". http://www.sos.arkansas.gov/rulesRegs/Arkansas%20Register/2007/jul_2007/209.02.0 7

- 005.pdf

. Bayer CropScience. 2011. "Ingite 280 SL Herbicide Label 5a " Bayer CropScience 2011. Web. September 28 2011 http://fs1.agrian.com/pdfs/Ignite_280_SL_Herbicide_Label5a.pdf

. Bennett, D. 2006. "2,4

- D Damages Arkansas Cotton." Delta Farm Press

. http://deltafarmpress.com/24

- d

- damages

- arkansas

- cotton

. Bennett, D. 2007. "Proposed Regulations Target Arkansas 2,4

- D and glyphosate drift." Delta Farm Press

. Carpenter, Janet, Allan Felsot, Timothy Goode, Michael Hammig, David Onstad, and Sujatha Sankula. 2002."Comparative Environmental Impacts of Biotechnology

- derived and Traditional Soybean, Corn, and Cotton Crops." 2011.July 8. Web. www.cast

- science.org

. Coalition. 2012. "JOINT STATEMENT OF DOW AGROSCIENCES A ND THE SAVE OUR CROPS COALITION REGARDING 2,4D TOLERANT CROPS AND THE 2,4D CHOLINE SALT HERBICIDE." Culpepper, A. S., J.R. Whitaker, A.W. MacRae, and A.C. York. 2008. "Distribution of Glyphosate

- Resistant Palmer Amaranth ( Amaranthus palmeri ) in Georgia and North Carolina During 2005 and 2006." Journal of Cotton Science 12.306

- 310. DAS.2012a. "DAS Comments to APHIS

- 2012

- 0019 on EA for DAS

- 68416

- 4 Soybean parts 2a, 2b, 2c, and 3." DAS.2012b. "DAS comments to APHIS

- 2012

- 0019. Stewardship. Herbicide volume estimate on soybean. off target exposure. trait stacking. 2,4

- D toxicity evaluation. analysis for the presence of dioxins and furans. errata. non ge soybean. regulatory status of herbicides that may be used on enlist soybean, 2,4

- D choline formulation, lac k of toxicological or biological synergistic effects between glyphosate and 2,4

- D, auxin resistant waterhemp, impact of enlist on herbicide use." DAS.2011. "Enlist TM Weed Control System

- Technical Bulletin." Dow AgroSciences.

Page 7

- 21DAS.2013. "Supplemental Docum entation in Support of Environmental Assessments in Response to Questions 8

- 11 Received December 12, 2012 regarding DAS

- 40278

- 9 corn and DAS

- 68416

- 4 soybean. Herbicide drift issues

". Ed. Hoffman, Neil. Department of Primary Industries. "Using Buffer Zones and Vegetative Barriers." Web. August 6, 2013 http://www.dpi.vic.gov.au/agriculture/farming

- management/chemical

use/agricultural

- chemical

- use/spraying

- spray

- drift

- and

- off

- target

- damage/ag0860

- using

buffer

- zones

- and

- vegetative

- barriers

- to

- reduce

- spray

- drift

. Dexter, A.G. 1993. Herbic ide Spray Drift

. http://library.ndsu.edu/tools/dspace/load/?file=/repository/bitstream/handle/10365/ 3067/126dex93.pdf?sequence=1

. Driftwatch. "National Specialty Crop Site Registry." Web. August 6, 2013 (https://driftwatch.org/.) Feitshans, T.A. 1999. "An analysis of state pesticide drift laws." San Joaquin Agriculture Law Review 9.37: 37

- 93. http://nationalaglawcenter.org/assets/bibarticles/feitshans_drift.pdf

. Fishel, Fred. 1997. "Pesticides and the Environment." Heap, I. 2011. "The International Survey of Herbicide Resistant Weeds." (2011). We b. April 24, 2011 www.weedscience.com

. Industry Task Force. 2006. "Environmental fate of 2,4

- D." http://www.24d.org/backgrounders/ body.aspx?pageID=30&contentID=134

. Industry Task Force II. 2013. "FAQs." Copyright 2013 Industry Task Force II on 2,4

- D Research Data 2013. Web http://www.24d.org/faqs/d efault.aspx?pageID=10&contentID=174&#q0

. Jordan, T., N. Glenn, B. Johnson, and T. Bauman. 2009. "Reducing Spray Drift from Glyphosate and Growth Regulator Herbicide Drift Caution." Purdue University Weed Science 2009. Web. March 14 2011 http://www.ag.purdue.edu/btny/weedscience/Documents/ReducingDrift09.pdf

. Madden, Nicholaus M. , Randal J. Southard, and Jeff P. Mitchell. 2009. Soil Water Content and Soil Disaggregatio n by Disking Affects PM10 Emissions : University of California

- Davis. Maynard, E, B Overstreet, and J. Riddle. 2012. "Pesticide Drift and Organic Production." Driftwatch . Purdue Extension 2012. Web. August 6, 2013 http://www.extension.purdue.edu/extmedia/HO/DW

- 1

- W.pdf

. Mohr, M. "Reducing Pesticide Drift. Specialty Crops and Conventional Crops as Good Neighbors." Web. August 6, 2013 https://my

s.extension.uiuc.edu/documents/96011100611061 1/reducingdrift.pdf. National Pesticide Information Center. 2,4

- D Technical Fact Sheet

. http://npic.orst.edu/factsheets/2,4

- DTech.pdf

. Nice, G.R.W., B. Johnson, and T.T. Bauman. 2004. Amine or e ster, which is better? http://www.btny.purdue.edu/weedscience/2004/articles/amineester04.pdf

. Owen, M. D., B. G. Young, D. R. Shaw, R. G. Wilson, D. L. Jordan, P. M. Dixo n, and S. C. Weller. 2011. "Benchmark study on glyphosate

- resistant crop systems in the United States. Part 2: Perspectives." Pest Management Science 67.7: 747

- 57. http://www.ncbi.nlm.nih.gov/pubmed/21452168

. Owen, M.D.K. 2008. "Weed species shifts in glyphosate

- resistant crops." Pest Management Science 64.4: 377

- 87. http://www.ncbi.nlm.nih.gov/pubmed/182320 55

.

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- 22Schultz, H.B., N.B. Akesson, W.E. Yates, and K.H. Ingebretson. 1956. "Drift of 2,4

- D applied by plane." California Agriculture .August: 4

- 14. http://ucce.ucdavis.edu/files/ repositoryfiles/ca1008p4

- 64547.pdf

. Towery, D., and S. Werblow. 2010."Facilitating Conservation Farming Practices and Enhancing Environmental Sustainability with Agricultural Biotechnology." 28. Web. November 9, 2010 http://www.ctic.purdue.edu/media/pdf/Biotech_Executive_Summary.pdf

. Tu, M., C. Hurd, and JM Randall. 2001 Weed Control Methods Handbook: Tools and Techniques for Use in Natural Areas . Ed. Conservancy, The Nature: UC Davis, CA. University of Missouri. 1997. "Pesticides and the Environment." 1997. Web http://extension.missouri.edu/p/G7520

. US

- EPA.2013. "2,4

- D Final Work Plan

- Registration Review Case Number 73." Ed. Office of Chemical Safety and Pollution Prevention. Washington, D.C.: U.S. Environmental Protection Agency. Vol. 2013 of Docket Number EPA

- HQ

- OPP

- 2012

- 0330

. h ttp://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPP

- 2012

- 0330

- 0024

. US

- EPA. 2005a. "2,4

- D RED Facts." 2005a. Web. August 10 2011 http://www.epa.gov/oppsrrd1/REDs/factsheets/24d_fs. htm

. US

- EPA.2012a. "2,4

- D. Human Health Assessment Scoping Document in Support of Registration Review." Ed. Office of Chemical Safety and Pollution Prevention. Washington, D.C.: U.S. Environmental Protection Agency. 36. Vol. 2013. http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPP

- 2012

- 0330

- 0004

. US

- EPA. 2005b. "Attachment III: Environmental Risk Assessment of Plant Incorporated Protecta nt (PIP) Inert Ingredients." U.S. Environmental Protection Agency 2005b. Web. July 20 2011 http://www.epa.gov/scipoly/sap/meetings/2005/de cember/pipinertenvironmentalrisk assessment11

- 18

- 05.pdf

. US

- EPA.2012b. "EPA Denial of November 6, 2008 NRDC Petition to Cancel All 2,4

- D Registrations." Ed. Wu, Dr. Solomon and Ms. Personnal Communication ed. US

- EPA. 2004. "Glyphosate Analysis of Risks to E ndangered and Threatened Salmon and Steelhead." U.S. Environbmental Protection Agency 2004. Web. January 24 2012 http://www.epa.gov/espp/litstatus/effects/glyphosate

- analysis .pdf

. US

- EPA. 2012c. "Pesticide issues in the works: pesticide volatilization." 2012c. Web http://www.epa.gov/opp00001/about/intheworks/volatilization.htm

. US

- EPA. 2010. "Pest icide Registration Manual: Chapter 11

- Tolerance Petitions." U.S. Environmental Protection Agency 2010. Web. November 3 2011 http://www.epa.gov/pesticides/bluebook/chapter11.html

. US

- EP A. 2000. Profile of the Agricultural Crop Production Industry . Washington: U.S. Environmental Protection Agency

- Office of Compliance Sector Notebook Profile. http://www.epa.gov/compliance/resources/publications/assistance/sectors/notebo oks/agcrop.pdf

. US

- EPA.2008. "Quizalofop Final Work Plan

- Registration Review of Quizalofop

- ethyl (128711) and Quizalofop

- p

- ethyl (128709)." Ed. Office of Prevention, Pesticides, and Toxic Substances,. Washington, D.C.: U.S. Environmental Protection Agency. 8 of Docket Number EPA

- HQ

- OPP

- 2007

- 1089

. http://www.regulations.gov/#!d ocumentDetail;D=EPA

- HQ

- OPP

- 2007

- 1089

- 0026

. US

- EPA. 2007. Quizalofop Summary Document, Registration Review: Initial Docket, December 2007, Case Number 7215

.

Page 7

- 23US

- EPA. 1993. R.E.D. Facts

– Glyphosate. Prevention, Pesticides and Toxic Substances Washington: U. S. Environmental Protection Agency. http://www.epa.gov/oppsrrd1/REDs/factsheets/0178fact.pdf

. US

- EPA. 2009. Registration Review

- Preliminary Problem Formulation for the Ecological Ris k and Drinking Water Exposure Assessments for Glyphosate and Its Salts (PC Code 417300, 103601, 103604, 103607, 103608, 103613, 103603, 103605, 128501). Washington, D.C. http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPP

2009

- 0361

- 0007

. US

- EPA. 2005c. Reregistration Eligibility Decision for 2,4

- D . Washington: U.S. Environmental Protection Agency. http://www.epa.gov/oppsrrd1/REDs/24d_red.pdf

. US

- EPA. 2002. "Summary of Analytical Chemistry and Resdue Data for Registration of Trangenic Cotton (ID# 0F06140)." USDA

- NASS. 20 06. Agricultural Chemical Usage 2005 Field Crops Summary : United States Department of Agriculture

- National Agricultural Statistics Service. htt p://usda.mannlib.cornell.edu/usda/nass/AgriChemUsFC//2000s/2006/AgriChe mUsFC

- 05

- 17

- 2006.pdf

. USDA

- NRCS. 2000. Conservation Buffers to Reduce Pesticide Losses . USDA: USDA. http://w ww.in.nrcs.usda.gov/technical/agronomy/newconbuf.pdf

.

Page 7

- 24

### Herbicides used on DAS Corn and Soybean Appendix 8.

Page 8

- 1Herbicides Used on DAS Corn and Soybean Three petitions submitted by DAS to APHIS seek deter minations of nonregulated status for GE maize and soybean cultivars engineered for resistance to herbicides. The three petitions are as follows:

APHIS Petition 09

- 233

- 01p ( DAS, 2010a ) is for GE maize ( Zea mays ) designated as event DAS

40278

- 9 corn . It is engineered for increased resistance to certain broadleaf herb icides in the phenoxy auxin group such as 2,4

- D (2,4

- dichlorophenoxyacetic acid ) . DAS

- 40278

- 9 corn is also resistant to grass herbicides classified as aryloxyphenoxypropionate (AOPP) acetyl coenzyme A carboxylase (ACCase) inhibitor s, such as quizalofop

- p

- ethyl (quizalofop) , that are referred to as fop herbicides

.

APHIS Petition 09

- 349

- 01p ( DAS, 2010b ) is for a GE soybean ( Glycine max ) variety designated DAS

- 68416

- 4 soybean

. The aad

- 12 gene in DAS

- 68416

- 4 soybe an expresses the AAD

- 12 protein, which degrades 2,4

- D into herbicida lly inactive 2,4

- dichlorophenol. D AS

- 68416

- 4 soybean also contains the PAT protein, conferring resistance to the herbicide glufosinate.

APHIS Petition Number 11

- 234

- 01p ( DAS, 2011d ) is for non

- regulatory status determination of event DAS

- 44406

- 6 soybean, which is genetically engineered for increased resistance to certain broadleaf herbicides , including the nonselective herbicides glufosinate

, glyphosate , and 2,4

- D

. The only difference between these two soybean events is that r esistance to glyphosate in DAS

68416

- 4 soybean will be achieved by traditional breeding wi th another soybean containing the 2mEPSPS gene, while DAS

- 44406

- 6 soybean has been genetically engineered with this gene.
A brief overview of the four herbicides (glyphosate, 2,4

- D, quizalofop, and glufosinate) that are intended to be used on the three DAS events are presented in the following sections. The proposed uses of these herbicides on DAS

- 40278

- 9 corn and DAS

- 68416

- 4 soybean (which would also include DAS

- 44406

- 6 soybean ) and any EPA assessments performed assessing the potential effects from the ne w uses are summarized.

2,4

- D

Background and Current Uses 2,4

- D is in the phenoxy or phenoxyacetic acid family and is listed as an herbicide, a plant growth regulator, and has been reported to elicit fungicid al properties at concentrations in ex cess of
ap proved application rates . Its main use is as a selective post

- emergence herbicide for controlling broadleaf weed species. The herbicide is approved for use on a wide variety of crops and has more than 600 registered end

- use products for use on more than 300 distinct agricultural and residential sites, including t errestrial and aquatic settings ( US

- EPA, 2005b )

. Agriculturally, it is used on a variety of crops including corn, rice, sorghum, sugar cane, wheat, rangeland, and pasture. In addition, 2,4

- D is used to control unwanted vegetative growth on utility corridors, rights

- of

- way, roadsides, non

- crop areas, managed forest, and lawn and turf areas. I t is also used to control aquatic and nuisance weeds, e.g., p urple loosestrife ( Industry Task Force II, 2005 )

. 2 ,4

- D controls many broadleaf weeds including carpetweed, dandelion, coc klebur, horseweed, morning glory, pigweed sp., lambsquarters, ragweed spp., shepherd’s

- purse, and velvetleaf. It

Page 8

- 2causes some plant damage to grasses at early growth stages in corn, and little to no plant damage in other grasses such as wheat and rice ( Industry Task Force II, 2005 )

. The herbicide 2,4

- D is currently available in ten molecular forms: 2,4

- dichlorophenoxyacetic acid, dimethylamine salt of 2,4

- D, 2

- ethylhexyl ester of 2,4

- D, butoxyethyl ester of 2,4

- D, triisopropanolamine salt of 2,4

- D, isopropylamine salt of 2,4

- D, diethanolamine salt of 2,4

- D, sodium salt of 2,4

- D, isopropyl ester of 2,4

- D, and choline salt of 2,4

- D ( US

- EPA, 2013b )

. 2,4

- D is formulated primarily as an amine salt in an aqueous solution or as an ester in an emulsifiable
concentrate ( US

- EPA, 2005b )

. The mode of action of 2,4

- D is described as an “auxin mimic,” meaning that it kills the target weed by mimicking auxin plant growth hormones

, such as indole acetic acid (IAA ) ( Tu et al.

, 2001 )

. Auxins and synthetic auxinic herbicides regulate virtually every aspect of plant growth and development; at low doses, auxinic herbicides possess similar hormo nal properties to natural auxin ( Kelley and Riechers, 2007 )

. However, as rates increase, they can cause various plant growth abnormalities in sensitive di cots ( Tu et al. , 2001 )

. Observable plant responses to 2,4

- D can include epinasty, root growth inhibition, meristematic proliferation/callusing, leaf cupping/narrowing, stem cracking, adventitious root formation, senescence, and chlorosis. This uncontrolled and disorganized plant growth eventually leads to plant death when applied at effective doses ( Tu et al. , 2001 )

. 2,4

- D controls many b roadleaf weeds including carpetweed, dandelion, cocklebur, horseweed, morning glory, pigweed sp., lambsquarters, ragweed spp., she pherd’s

- purse, and velvetleaf ( Industry Task Force II, 20 05 )

. The 2,4

- D mode of action as a synthetic auxin is not changed by the formulations, but the chemical and physical properties of each formulation influence the selection of equipment, mitigation measures adopted in the field to minimize off

- target imp acts, and formulation

- specific safety measures. For a major ity of use s, 2,4

- D is combin ed with other herbicides because it economically enhances the weed control spectrum of many other herbicides

, such as glyphosate, dicamba, mecoprop, and ALS herbicides ( US

- EPA, 2005b )

. The degradation products of 2,4

- D are 1,2,4

- benzenetriol, 2,4

- DCP
, 2,4

- dichloroanisole (2,4

- DCA ), 4

- chlorophenol, chlorohydroquinone (CHQ ), volatile organics, bound residues, and carbon dioxide

. T he EPA has de termined that residues other than 2,4

- D and 2,4

- DCP are not of risk concern due to low occurrence under environmental conditions, comparatively low tox icity, or a combination thereof ( US

- EPA, 2013b )

. Using pesticide usage data from the USDA

- NASS and Private Pesticide Market Research, EPA estimated that an average of nearly 29 million pounds of all forms of 2,4

- D were applied to agricultural crops in the U.S. annually between 2006 an d 2010 ( US

- EPA, 2012a ) . Based on average treated fraction of acreage, the crops with the highest uses of 2,4

- D were: almond (15%), apples (20%), barley (25%), cherries (15%), fallow (25%), hazelnuts (25%), nectarines (15%), oats (15% ), oranges (20%), peaches (20%), pears (15%), plums (15%), prunes (15%), sorghum (20%), sugarcane (40%), tangelos (30%), wheat (30%). All other treated crops averaged 10% or less of the total acreage grown ( US

- EPA, 2012a ) . Average ann ual use on lawns, turf, nurseries, etc. in commercial settings decreased from 5 million to 4 million pounds per year (2002, 2004, 2006). Homeowner and aquatic weed control uses have remained fairly constant with average annual uses of 9 to 9.5 million pou nds per year (2003, 2005) ( US

- EPA, 2013b )

.

Page 8

- 3For 2,4

- D, the current maximum approved usage rate is 4.0 lbs ae/A per year for asparagus, pome fruits, sugarcane, stone fruites, forestr y uses, and non

- cropland uses, among others. The maximum rate for aquatic uses is 10.8 lbs ae/acre foot for submerged aquatic plants. Typically, one to three applications are made per growing season. 2,4

- D is currently registered in the U.S. for use on corn. The currently approved application rates for field corn and popcorn are a maximum per

- year application rate of 3 lbs/acre and a maximum single application rate of 1.5 lbs/acre ( US

- EPA, 2013b )

. 2,4

- D is approved for use on soybean only for pre

- plant burndown application. Application rates on soybean are 0.5 or 1.0 lbs ae/A per application or 1.0 lbs ae/A p er crop per year. The herbicide may not be applied any later than 7 to 15 days (0.5

– 1.0 lb ae/A of ester formulations) or 15 to 30 days (0.5

– 1.0 lb ae/A of amine formulations) prior to planting due t o the potential for crop injury ( DAS, 2011a )

. Under Section 408 of FFDCA, EPA regulates th e levels of pesticide residues that can remain on food or food commodities from pesticide applications ( US

- EPA, 2010b ) . The tolerance level is the maximum residue level of a pesticide that can legally be present in food or feed, and if pesticide residues are found to exceed the tolerance value, the food is considered adulterated and may be seized. The EPA establishes tolerances to regulate the amount of pesticide residues that can remain on food or feed commoditi es as the result of pesticide applications. Table 8

- 1 shows the current tolerances for residues of 2,4

- D established for corn and soybean commodities ( US

- EPA, 2011a )

.
Table 8

- 1

. 2,4

- D Tolerances for Corn and Soybean Commodities

Commodity Residue (parts per million) Corn, field, forage 6.0 Corn, field, grain 0.05
Corn, field, stover 50 Soybean, forage 0.02 Soybean, hay 2.0 Soybean, seed 0.02
Source: ( US

- EPA, 2011b ) EPA is currently conducting a registra tion review of 2,4

- D which was begun in 2012 and is currently scheduled to be completed in 2017 ( US

- EPA, 2013a ) . According to EPA, as part of their review, a comprehensive ecological risk assessment, including an endangered species assessment, will be prepared for all uses of 2,4

- D. Additionally, EPA will conduct revised dietary, residential, and occupational risk assessments, incorporating any new toxicological or other r elevant data ( US

- EPA, 2013a ) . All documents related to the 2,4

- D registration review can be viewed at the registra tion review docket:
http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2012

- 0330

Page 8

- 4New 2,4

- D Choline Salt Formulation and Uses DAS has developed a new herbicide formulation containing 2,4

- D choline salt ( DAS, 2010b ; DAS, 2010a ; DAS, 2011a ) for additional pre

- and post

- emergence use with DAS

- 40278

- 9 corn
, DAS

- 68416

- 4 soybean, and DAS

- 44406

- 6 soybean

. The 2,4

- D

- resistan ce trait s allow for a later application of the herbicide in both soybean (R2 stage) and corn (V8 stage). The new formulation is reported to be chemically more stable, making it less volatile, than the currently used amine or ester formulations of 2,4

- D. In addition, the new formulation is reported to have minimized potential for physical drift in comparison to the currently used 2,4

- D ester and 2,4

- D dimethylamine (DMA) formulations, as well as decreased odor and improved handling ( DAS, 2011a ; DAS, 2011e )

. 2,4

- D choline salt is a quaternary ammonium salt that rapidly dissociates into a 2,4

- D anion and a choline cation. 2,4

- D choline salt is currently registered on a number of crops including: sugarcane, rice, pome fruits, stone fruits, conventional corn and soybeans, fallow land, turf, and tree and brush control. Dow Agrosciences LLC, the manufacturer and registrant of 2,4

- D choline salt, has submitted applications to EPA to add the following uses to the current 2,4

- D choline salt labels: 1) DAS

- 40278

- 9 corn, 2) DAS

- 68416

- 4 soybean, 3) EnlistTM corn (DAS

40278

- 9 corn stacked with a glyphosa te

- resistance trait), and EnlistTM soybean (DAS

- 68416

- 4 soybean stacked with a glyphosate

- resistance trait).

Two of the proposed registrations contain only 2,4

- D choline salt as the active ingredient, whereas the other two labels are for a 2,4

- D

- choline sal t/glyphosate mixture which DAS plans to market under the name Enlist Duo TM . The latter would allow applications to GE herbicide

resistant corn and soybean with resistance to both 2,4

- D and glyphosate. The 2,4

- D choline formulation GF

- 2654 TS would be used on DAS 68416

- 4 soybean and the 2,4

- D choline formulation GF

- 2654 TC used on DAS

- 40278

- 9 corn. The Enlist Duo TM formulations GF

- 2726 and GF

- 2727
, contain ing both 2,4

- D choline salt and glyphosate , would be applied on EnlistTM

corn and EnlistTM soybean, respe ctively

.
Proposed New 2,4

- D Use on Corn Although 2,4

- D is already used on corn, its use is limited beyond early seedling stages ( Wright et al.

, 2010 ) . Applications of 2,4

- D as a post

- emergent herbicide at later growth stages in conventional corn can cause significant malformations ( Wright et al. , 2010 ) . The proposed new use of 2,4

- D choline on DAS

- 40278

- 9 corn includes a pre

- emergent and up to two post

- emergent applications ( DAS, 2011b )

. Table 8

- 2 compares the current the use patterns for 2,4

- D on field corn with the proposed use patterns for 2,4

- D on DAS

- 40278

- 9 corn

. The comparison is also shown graphically in Figure 8

- 1.

The label directions indicate no more than one pre

- emergence application and no more than two post

- emergence applications per use season. Proposed application rates for this new use of 2,4

- D

on DAS

- 40278

- 9 corn are up to 1 lb acid equivalent (ae)/acre (1,120 g ae/h a) as a pre

- emergent herbicide and up to two applications between 0.5 to 1.0 lbs ae/acre (560 and 1,120 g ae/ha) for post

- emergence. The post

- emergence applications must be at a minimum of 12

- days apart during the first 3

- 5 weeks before the corn reaches 6

- 8 inches in height and again up to the V8 [48

- inch] stage of corn. These application rates are based on the currently approved rates for field corn and popcorn, which establish a maximum

- per

- year application rate of 3 lbs/acre, and a

Page 8

- 5maximum single application rate of 1.5 lbs/acre ( DAS, 2011f ) . Post

- emergence application of 2,4

- D, as specified on the draft label, could not occur within 30 days of forage harvest. The proposed preharvest interval (PHI) for corn is 30 days. Applications are to be made using groundboom equipment. Aerial application and chemigation are prohibited. The new use pattern and draft label are subject to regulatory approval by EPA.

Table 8

- 2 : Comparison of Current and Proposed Application Rates for 2,4

- D on Corn

Crop Stage Conventio nal Field Corn Proposed New Use on DAS

- 40278

- 9 Corn Maximum Application Rate (lb/acre) 1,2 Directions and Timing Maximum Application Rate (lb/acre) 1,2 Directions and Timing

Pre

- plant or Pre

- emerg ence 1.0 Apply before corn emerges to control emerged broadleaf weed seedlings or existing cover crops 1.0 Apply before corn emerges to control emerged broadleaf weed seedlings

or existing cover crops

Post

- emerg ence 0.5 Apply when weeds are small and corn is less than 8 inches tall (to top of canopy). When corn is over 8 inches tall, use drop nozzles and keep spray off foliage. 0.5 to 1.0 Apply after crop and weed emergence but before corn exceeds growth stage V8 or

48” in height, whichever occurs first. Make 1 to 2 applications with a minimum of 12 days between applications.

Pre

- harvest 1.5 Apply after hard dough (or at denting) stage. --- ---
T otal Annual Maximum Application 3.0

--- 3.0

---

Source: ( DAS, 2011f ) 1. All values expressed as acid equivalents. 2. 1 lb/acre is the equivalent of 1,120 g/hectare.

Page 8

- 6Source: ( DAS, 2012b )

. Figure 8

- 1

. Current use pattern of 2,4

- D on conventional corn and proposed new use of 2,4

- D choline salt on DAS

- 40278

- 9 corn.

New 2,4

- D Use on Soybean Currently, 2,4

- D is approved for use on soybean only for pre

- plant burndown application. Application rates on soybea n are 0.5 or 1.0 lbs ae/A per application or 1.0 lbs ae/A p er crop per y ear ( US

- EPA, 2005b )

. I t may not be applied any later than 7 to 15 days (0.5

– 1.0 lb ae/A of ester formulations) or 15 to 30 days (0.5

– 1.0 lb ae/A of amine formulations) prior to planting due to the potential for crop injury ( DAS, 2010b )

. The proposed new use of 2,4

- D choline on DAS

- 68416

- 4 soybean (or DAS

- 44406

- 6 soybean) includes a single pre

- plant or pre

- emergent application and up to two post

- emergent applications ( DAS, 2011b ) . Specifi cally, an application of 2,4

- D at pre

- plant/burndown or pre

- emergence (1.0 lb ae/A) without plant back restrictions would be allowed and/or one or two over

- the

- top post

- emergence applications (0.5

- 1.0 lb ae/A ) at least 1 2 days apart up to the R2 stage (f ull flowe r) of development ( see Figure 8

- 2 ) ( DAS, 2010b ) . Thus, the proposed maximum total seasonal application rate of 2,4

- D on DAS

- 68416

- 4 soybean (or DAS

- 44406

- 6 soybean ) would increase from 1.0 lb ae/A (current) to 3.0 lb ae/A per year . (This proposed new seasonal rate is
t he same current EPA

- approved maximum annual use rate of 2,4

- D for popcorn and field corn). Post

- emergence application of 2,4

- D, as specified on the draft label, coul d not occur within a PHI of 30 days ( DAS, 2011a ; DAS, 2011c ) . The new use pattern and draft label are subject to regulatory approval by EPA. T able 8

- 3 presents a comparison of the current and proposed

Page 8

- 7application rates of 2,4

- D on soybean and DAS

- 68416

- 4 (or DAS

- 44406

- 6 soybean ) ( DAS, 2010b )

.

Source: ( DAS, 2010b )

. Note: the new 2,4

- D use pattern would be the same for DAS

- 44406

- 6 soybean. Figure 8

- 2

. Proposed 2,4

- D Application R ates on DAS

- 68416

- 4 Soybean Compared to Current Application Rates Per mitted for Conventional Soybean

Table 8

- 3

. Comparison of Current and Proposed Application Rates of 2,4

- D on Soybean

Crop Stage Current Use Pattern

- Conventional Soybean Proposed New Use Pattern

– DAS

- 68416

- 4 Soybean ( or DAS

- 44406

- 6 Soybean )
Maximum Application Rate (lb/acre) 1 Directions and Timing Maximum Application Rate (lb/acre) 1 Directions and Timing

Pre

- plant (burndown) or Pre

- emergence 0.5

- 1.0 Pre

- plant: Apply before soybean emerges to control emerged broadleaf weed seedlings or existing
cover crops 1.0 Pre

- plant: Apply any time prior to and up through soybean planting but before soybean emerges to control emerged broadleaf weed seedlings or existing cove r crops. Pre

- emergence: Apply any time after planting but before soybean emerges to control broadleaf weed seedlings or existing cover crops.

Page 8

- 8Crop Stage Current Use Pattern

- Conventional Soybean Proposed New Use Pattern

– DAS

- 68416

- 4 Soybean ( or DAS

- 44406

- 6 Soybean )
Maximum Application Rate (lb/acre) 1 Directions and Timing Maximum Application Rate (lb/acre) 1 Directions and Timing

Post

emergence -- 2

-- 0.5

- 1.0 Apply when weeds are small and soybean growth stage is no later than R2 (full flowering stage). Make one to two applications with a minimum of 12 days between applications.

Total Annual Maximum Application 1.0

-- 3.0

--

1 All values expressed as acid equivalents

2 Not applicable
Source: ( DAS, 2011c )

.

EPA Assessments of Proposed New 2,4

- D Choline Salt Formulation and Uses on 2,4

- D

Resistant Corn and Soybean Under FIFRA, EPA regulates the use of herbicides, requiring registration of a pesticide for a specific use prior to distribution or sale of the pesticide for a proposed use pattern. The process of registering a pesticide is a scientific, legal, and admini strative procedure through which EPA examines the ingredients of the pesticide; the particular site or crop on which it is to be used; the amount, frequency, and timing of its use; and storage and disposal practices. In evaluating a pesticide registration application, EPA assesses a wide variety of potential human health and environmental effects associated with use of the product. Prior to registration for a new use for a new or previously registered pesticide, th e p roducer of the pesticide must provide data from tests done according to EPA guidelines. EPA must determine through this submitted test data that the pesticide will not cause unreasonable adverse effects on the environment and non

- target species when used in accordance with label instructions and will result in a reasonable certainty of no harm to humans

.
EPA must also approve the language used on the pesticide label in accordance with 40 CFR part 158. The EPA pesticide registration process involves the design of use restrictions that, if followed, have been determined to be protective of worker health. Growers are required to use pesticides consistent with the application instructions provided on the EPA

- approved pesticide labels. The overall intent of the label is to provide clear directions for effective product performance while minimizing risks to human health and the environment ( US

- EPA, 2010c )

.

Page 8

- 9Based on the studies submitted on 2,4

- D choline salt formulation by DAS

, EPA has condu cted draft assessments on the potential environmental fate

, ecological effects , and human health effects of the proposed new uses of 2,4

- D choline salt. The conclusions from those assessments are summarized in this section. EPA will be publishing these co mplete draft analyses in the Federal Register for public comment.

Environmental Fate and Ecological Risks

EPA E nvironmental Fate and Effects Division (E FED ) assessed the ecological risks to listed and

non

- listed species associated with the proposed new use s of 2,4

- D choline salt on 2,4

- D

- resistant corn and soybean. The assessment examined the effects of 2,4

- D choline salt (and 2,4

- DCP, when relevant) on aquatic and terrestrial environments primarily through the routes of spray drift, volatile (vapor) drift , and runoff. Modeled application rates represent the maximum use pattern s of the proposed label s for use on 2,4

- D

- resistant corn and soybean.

The results are summarized as follows:

No potential direct risks from the proposed applications of 2,4

- D choline salt to herbicide

tolerant corn and soybeans were identified for the following:

• Birds (chronic)

,
• Aquatic plants

,
• Freshwater fish (acute and chronic)

,
• Estuarine/marine fish (acute and chronic)

,
• Freshwater invertebrates (acute and chronic)

,

• Estuarine/marine invertebrates (acute and chronic)

,
• Aquatic plants , and

• Terrestrial insects

. The screening level risk assessment for non

- listed species identified these groups as being potentially at direct risks from exposures from the proposed new uses of 2,4

- D cholin e salt :

• Mammals (acute and chronic)

,
• Birds , reptiles, terrestrial

- phase amphibians (acute) , and

• Terrestrial plants

. In addition, the screening level risk assessment identified all non

- listed taxa as potentially at i ndirect risks from the proposed uses of 2,4

- D choline salt because of potential dependencies (e.g., food, shelter, habitat) on species that are directly affected

. Information, such as biological distribution, species biology, spray drift properties specific to the 2,4

- D choline formulations,

an d mitigation efforts in regions where the pesticide is used, could be used to reduce the uncertainty regarding potential direct and indirect effects.
An assessment of the direct and indirect risks to listed species for which a potential for risk was identi fied in the screening level assessment is under development by EPA. This assessment will address the specific geographical and biological characteristics of each species potentially at risks from exposures to 2,4

- D. When this refined, species

- specific as sessment is completed,

Page 8

- 10EPA will be able to identify which species are at direct and indirect risks from exposures to 2,4

- D.
A spray drift analysis using the GF2726 formulation indicated that buffers c ould reduce risk quotients for birds (acute), mammals (a cute and chronic), and terrestrial plants below the Agency’s levels of concern. The results of the buffer analysis indicated that riskes below levels of concern can only be achieved through the combination of the AIXR 11004 nozzle and GF

2726 formulation. Final species

- specific buffer distances remain uncer review and refinement. The locations of the buffers would be dependent on species distribution, species biology, and any mitigation efforts proposed by the registrant.
EPA will be publishing these com plete draft analyses in the Federal Register for public
comment.

Human Health Risk Assessment The EPA Health Effects Division (HED) of the Office of Pesticide Programs (OPP) is charged with estimating the risk to human health from exposure to pesticides. HED evaluated hazard and exposure data and conducted dietary, residential (non

- occupational), aggregate, and occupational exposure assessments to estimate the risk to human health that will result from the proposed new use of 2,4

- D choline salt on 2,4

- D

- re sistant corn and soybean. Based on the ir draft human health risk assessment, EPA HED recommends for a registration for the use of 2,4

- D choline on 2,4

- D

resistant corn and soybean. EPA identified additional data needed, specific tolerance recommendations , and label modifications. A summary of the results of the assessment are provided, below. The draft assessment will be published by EPA in the Federal Register for public review and comment.

Hazard Characterization: Based on its review of hazard data , EPA concluded that 2,4

- D ’s principal toxic effects are changes in the kidney, thyroid, liver, adrenal, eye, and ovaries/testes in the rat following exposure via the oral route at dose levels above the threshold of saturation of renal clearance. No systemic toxicity was observed in rabbits following repeated exposure via the dermal route at dose levels up to the limit dose. Neurotoxicity was observed in the acute neurotoxicity study in rats at the high dose. In an extended 1

- generation reproductive toxicity study in rats, reproductive toxicity, developmental neurotoxicity, and immunotoxicity were not observed, and the thyroid effects observed at dose levels up to /approaching renal saturation were considered treatment

- related, although not adverse. Maternal and developmental toxicity were observed at high dose levels exceeding the threshold of saturation of renal clearance. T here are no residual uncertainties for pre

- and/or postnatal toxicity. 2,4

- D is not acutely (lethal) toxic via the oral, dermal, and inhalation routes, is not a dermal irritant or a dermal sensitizer, but it is a severe eye irritant

. 2,4

- D has been classified as a Category D chemical, i.e., not classifiable as to human carcinogenicity.
Dietary Exposure and Risk Assessment: Acute and chronic aggregate (food + dietary d rinking water) exposure and risk assessments were conducted for the new proposed use of 2,4

- D choline salt. EPA HED determined that t he resulting acute food plus drinking water risk estimates are not of concern to (≤100% of the acute population adjusted dose ( aPAD) ) at the 95 th percentile of the exposure distribution for the general population and all population subgroups. The res ulting acute risk estimate for children 1 to 2 years old (the subgroup with the greatest exposure) was
Page 8

- 1114 % of the aPAD at the 95 th percentile of the exposure. The resulting chronic risk estimates are not of concern to EPA HED for the general population and all population subgroups . The most highly exposed population was children 1 to 2 years old, utilizing 15 % of the chronic PAD (cPAD).

Residential (Non

- Occupational ) Exposure and Risk Assessment: There is n o potential hazard vi a the dermal route f or 2,4

- D, therefore the handler assessment included only the inhalation route of exposure and the post

- application assessment included only the inhalation and incidental oral route of exposure. The residential handler and post

- applicat ion risk estimates are not of concern for 2,4

- D for all scenarios and all routes of exposure.
Exposure to drift and volatilization, and the appropriate available data, were considered in this assessment due to the anticipated market expansion. Concernin g spray drift, the residential post

application exposure assessment for registered use as direct application to turf is protective of potential deposition on turf from spray drift for the proposed use of 2,4

- D choline on herbicide

tolerant corn and soybean . The potential exposure to vapor phase 2,4

- D residues emitted from treated fields for the proposed uses of 2,4

- D choline has been evaluated in this assessment. The results indicate that volatilization of 2,4

- D from treated crops does occur and could result in bystander exposure to vapor phase 2,4

- D. Modeling results, however, indicate that airborne concentrations, even at the edge of the treated fields, are not of concern.
Aggregate Risk Estimates: The acute aggregate risk assessment include only food and water
exposure. The resulting acute food plus drinking water risk estimates are not of concern to EPA HED (≤100% aPAD) at the 95 th percentile of the exposure distribution for the general population and all population subgroups.

The short

- term agg regate risk assessment includes food, water, and residential exposure. According to EPA HED, the resulting short

- term aggregate risks are not of concern (margins of exposure (MOEs) > level of concern (LOC) of 100) for adults and children.

The re are no int ermediate

- term residential exposure to 2,4

- D; therefore the intermediate

- term aggregate risk assessment include only food and drinking water exposure. Furthermore, the chronic aggregate risk assessment includes only food and water exposure. The chronic f ood plus drinking water risk estimates are not of concern to EPA HED for the general population and all populations subgroups

. Occupational Exposure and Risk Assessment: Occupational handlers may apply 2,4

- D choline with groundboom equipment. There is n o potential hazard via the dermal route f or 2,4

- D, therefore the occupational handler assessment included only the inhalation route of exposure. Occupational handler inhalation risk estimates are not of concern (i.e., MOEs > LOC of 300) for all scenarios for use of 2,4

- D choline on herbicide

- tolerant corn and soybean. At baseline personal protective equipment (PPE) (i.e., no respirator), the occupational handler inhalation MOE is 4,900 for mixer/loaders and 3,200 for applicators using groundboom equipment

. There is n o potential hazard via the dermal route f or 2,4

- D ; therefore, a quantitative occupational post

- application dermal risk assessment was not completed. Furthermore, a quantitative post

application inhalation risk assessment was not performed for workers at this time; although the assessment was not performed, other exposure scenarios are expected to be protective of

Page 8

- 12potential worker post

- application inhal ation exposure. T he minimum Worker Protection Standard (WPS) restricted entry interval ( REI ) of 48 hours is adequate to protect agricultural workers from post

- application exposures to 2,4

- D

. Glyphosate

Background and Current Uses Glyphosate acid is a broad spectrum, nonselective s ystemic herbicide widely used to control most annual and perennial grass and broadleaf weeds in agricultural crops and non

- agricultural sites. The herbicide is registered for pre

- and post

- emergence application on a variety o f fruit, vegetable, and field crops, as well as for aquatic and terrestrial uses. Labeled uses of glyphosate include over 100 terrestrial food crops as well as other non

- food sites including forestry, greenhouse, non

- crop, and residential. Glyphosate can also be used as a plant growth regulator and accelerate fruit ripening. Additionally, glyphosate is registered for use on GE glyphosate

- resistant crops, including canola, corn, cotton, soybeans, alfalfa, and sugar beets. G lyphosate is the most widely use d herbicide on U.S. corn and soybean.

Glyphosate was first introduced under the trade name of Roundup TM by Monsanto in 1974. Glyphosate salts serve as the source of the active ingredient (ai) N

- (phosphonomethyl) glycine and improve handling, performance, and concentration of the glyphosate acid. Glyphosate is distributed in several forms, including technical grade glyphosate, isoproplyamine salt, monoammonium salt, diammonium salt, N

- methylmethanamine salt , trimethylsulfonium salt, or potassium salt ( US

- EPA, 2009c ) . I sopropylamine salt is the most typically used form in formulated products ( Henderson, 2010 )

. Glyphosate acid is a nonselective Group 9 herbicide and kills plants by inhibiting the 5

- enolpyruvylshikimate

- 3

- phosphate synthase (ESPS) enzyme. This enzyme is essential for the biosynthesis of aromatic amino acids (e.g., tyrosine, tryptophan, and phenylalanine) and other aromatic compounds in algae, higher plants, bacteria and fungi. By creating a deficiency in EPSP enzyme and aromatic amino acids production, glyphosate affects protein synthesis and plant growth ( US

- EPA, 2009 c )

. Glyphosate is absorbed across the leaves and stems of plants and moves throughout the plant, concentrating in the meristem tissue ( Henderson, 2010 )

. Based on pesticide usage data from USDA

- NASS, private pesticide market research, and California Department of Pesticide Regulation (DPR), EPA estimated glyphosate usage from 2004 through 2011. The crops with the highest glyphosat e uses (based on average treated fraction of acreage) were: almond (85%), apples (55%), apricots (55%), asparagus (55%), avocados (45%), barley (20%), blueberries (20%), canola (65%), cherries (65%), corn (60%), cotton (85%), cucumbers (20%), dates (20%), dry beans/peas (25%), fallow (55%), figs (40%), grapefruit (80%), grapes (70%), hazelnuts (70%), kiwifruit (30%), lemons (70%), nectarines (45%), olives (45%), onions (30%), oranges (90%), peaches (55%), peanuts (20%), pears (65%), pecans (35%), peppers (2 0%), plums (65%), pumpkins (20%), rice (25%), sorghum (40%), soybeans (95%), squash (20%), sugar beets (50%), sugarcane (45%), sunflowers (55%), tangelos (55%), tangerines (65%), tomatoes (35%), walnuts (75%), and wheat (25%). All other treated
crops avera ged 15% or less of the total acreage grown ( US

- EPA, 2012e )

.

Page 8

- 13The CP4 EPSPS protein confers resistance to glyphosate and has been used in many Roundup Ready TM crops (e.g., canola, corn, cotton, soybean, and sugar beet). Glyphosate may be used premergent, preplant incorporated, or postemergent with Roundup Ready TM crops. As listed on the Roundup TM herbicide labels, Roundup Original MAX TM , Roundup WeatherMAX TM , and Roundup PowerMAX TM products contain 48.8 percent of the potassium salt of glyphosate, equivalent to 4.5 lb of glyphosate ae per gallon (540 g glyphosate per liter ( L ) ). Glyphosate is also commonly used in conjunction with many ot her herbicides as a tank mix for both pre

plant/pre

- emergence weed control up through the 12

- leaf stage or until the corn reaches a height of 30 inches ( see, e.g., Loux et al. , 2011 )

. The current approved maximum pre

- emergence application of glyphosate on glyphosate

- resistant corn or soybeans is 3.7 lbs ae/a cre. A glyphosate post

- emergence application from 0.75 to 1.5 lbs ae/acre (total 2.25 lbs/acre/season post

- emergence) and an additional pre

- harvest application of 0.77 lbs/ae/acre are permitted. The current maximum total seasonal use rate for glyphosate on glyphosate

- resistant corn and soybean is 6 lbs ae/acre ( DAS, 2012c )

. Pesticide residue tolerances for glyphosate are listed in 40 CFR Part 180.364
, representing combined residues of glyphosate, N

- (phosphonomethyl)glycine and its metabolite N

- acetyl

glyphosate (expressed as glyphosate) ( US

- EPA, 2010a )

. Table 8

- 4 shows the curre nt tolerances for residues of glyphosate established for corn and soybean commodities.

Table 8

- 4

. Glyphosate Tolerances for Corn and Soybean Commodities Commodity Residue (parts per million) Corn, field, forage 13 Corn, field, grain 5 Corn, field, stover 100 Soybean, forage 100 Soybean, hay 200 Soybean, hulls 120 Soybean, seed 20
Source: ( US

- EPA, 2010a )

. EPA is currently conducting a registration review of glyphosate which was begun in 20 09 and is currently scheduled to be completed in 201 5 ( US

- EPA, 2009b ) . According to EPA, as part of their review, “ the Agency plans to require a number of ecological fate and effects studies, an acute and subchronic neurotoxicity study, and an immunotoxicity study through a data call

- in, which is expe cted to be issued in 2010. The new information will be used to conduct a comprehensive ecological risk assessment, including an endangered species assessment, as well as a revised occupational human health risk assessment, for all glyphosate pesticidal use s ( US

- EPA, 2009b ) .”

All documents related to the glyphosate registration review can be viewed at the registra tion review docket:
http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2009

- 0361

Page 8

- 14Glyphosate Use on DAS

- 40278

- 9 C orn , DAS

- 68416

- 4 S oybean , and DAS

- 44406

- 6 S oybean DAS’ new pre

- mix of 2,4

- D choline and glyphosate DMA, the Enlist TM Duo formulations GF

2726 and GF

- 2727 , will be formulated as an approximate 1:1 ratio of 2,4

- D choline to glyphosate DMA. If approved by EPA, glyphosate could be applied to EnlistTM Corn and EnlistTM Soybean ( DAS

- 40278

- 9 corn and DAS

- 68416

- 4 soybean stacked with a glyphosate

resistance trait (or DAS

- 44406

- 6 soybean ) at pre

- plant/burndown at 0.5 to 1.0 lb ae/acre and up to two post

- emergence applications at 0.5 to 1.0 lb ae/, for a maximum total seasonal application
rate of 3.0 lb ae/acre. This compares to current glyphosate use on glyphosate

- resistant corn and soybeans of a maximum pre

- emergence application of 3.7 lbs ae/acre and post

- emergence applications from 0.75 to 1.5 lbs ae/acre (total 2.25 lbs/acre/season post

- e mergence) and an additional pre

- harvest application of 0.77 lbs/ae/acre. The current maximum total seasonal use rate for glyphosate on glyphosate

- resistant corn and soybeans is 6 lbs ae/acre ( DAS, 2011f ; DAS, 2012a )

. Quizalofop

Background and Current Uses Quizalofop

- p

- ethyl is a selective, systemic post

- emergence phenoxy herbicide that is toxic to many annual and perennial grasses. It belongs to a subclass of phenoxy compounds known as aryloxyphenoxys ( “ fops ” ). Quizalofop

- p

- ethyl is absorbed from the leaf surface and is moved throughout the plant. It accumulates in the active growing regions of stems and roots. Most non

graminaceous plants (dicots and sedges) are tolerant to quiz alofop

. Dicotyledonous (or dico t) plants contain a prokaryotic form of ACCase (an enzyme found in chloroplasts) which is insensitive to “fop” herbicides. In contrast, monocotyledonous (or monocot) plants contain a sensitive eukaryotic form of ACCase in the plastid ( DAS, 2010a ) . This is the primary reason that the “fop” herbici des are generally good graminicides 1 , with little activity on dicot plants. In addition, some grass species, including some cereal crops and weeds (e.g.

, annual bluegrass and wild oats), are tolerant of some of these herbicides (i.e.

, clethodim, quiz alofo p , and others) due to their ability to metabolize the herbicides to inactive forms ( Devine and Shukla, 2000 ; Powles and Preston, 2009 )

. The aryloxyphenoxypropionates ( AOPP ) herbicides inhibit chloroplastic ACCase, which catalyzes the first committed step in fatty acid biosynthesis, causing plant death ( Burton et al.

, 1989 ) . The herbicidal activity of quiz alofop

- ethyl ester was first reported in 1983

, and quiz alofop

- ethyl was fir st approved for use in a registered herbicide product in the U.S. in 1988 ( DAS, 2010a ; DuPont, 2010 )

. 2 However, all end use product registrations were cancelled prior to 1996 and it was replaced by the more active quiz alofop

- P

- ethyl (pure R

- enatiomer of quiz alofop racemic mixture), which first was approved for use in a registered prod uct in 1990 ( DuPont, 2010 )

.

1 A graminicide is an herbicide used for the control of grass weeds ( of the former family ''Gramineae').'

2 Reference to the DuPont Assure ® II label is for illustration only, and is not intended to infer any recommendation for the use of this product by APH IS or the USDA.

Page 8

- 15The “fop” herbicides (AOPP ACC ase inhibitors) have been registered for crop use for more than 20 years ( USDA

- APHIS, 2010 ) . The “fop” herbicides traditionally have not been used to control weed species in cornfield s because, as a grass (Poaceae family) species, corn is damaged by AOPP ACCase inhibitor activity. The registration and use of “fop” herbicides has been primarily on broadleaf crops, such as soybean, to control grass weed species, although certain cereal plant varieties have a level of tolerance to some “fops ” ( see DuPont, 2010 ) . According to the USDA

- NASS Agricultural Chemical Use Database, “fop” type herbicides were used for weed control on at least 23 food crop species between 1990 and 2006, totaling more than 16 million pounds of active ingredient ( USDA

- NASS, 2011 )

. The currently registered uses include canola, crambe, cotton, crops grown for seed, eucalyptus, dry beans (including Chickpea), dry and succulent peas, flaxseed, h ybrid poplar plantings, lentils, mint (spearmint and peppermint), pineapple, ryegrass grown for seed, snap beans, soybeans, sugar beets, sunflowers, and noncrop areas. Current allowable rates for this herbicide vary from 0.0172 to 0.344 lb ai/acre, depend ing on crop and weed conditions (see EPA approved label for Assure II ) ( DAS, 2010a ; D uPont, 2010 )

. Pesticide residue tolerances for quizalofop are listed in 40 CFR Part 180.4 41. As quizalofop is not currently approved by EPA for use on corn, only residue limits for soybean commodities are shown in Table 8

- 5

, representing combined res idues of combined residues of quizalofop ethyl, quizalofop, and quizalofop methyl ( US

- EPA, 2012b )

.
Table 8

- 5

. Quizalofop Tolerances for Soybean Commodities Commodity Residue (parts per million) Soybean, flour 0.5 Soybean, hulls 0.02 Soybean, meal 0.5 Soybean, seed 0.05 Soybean, soapstock 1.0
Source: ( US

- EPA, 2012b ) Note: quizalofop is not currently approved for uses on corn. The Registration Review for q uizalofop was begun in 2007 and a final workplan was completed in June of 2008. EPA has not published a proposed decision schedule for quizalofop as of this
assessment : http://www.epa.gov/oppsrrd1/registration_review/schedule.htm

Documents related to the EPA review are posted as part of the Registration Review of Quizalofop

- ethyl (128711) and quizalofop

- p

- ethyl (128709) docket ( EPA

- HQ

- OPP

- 2007

- 1089 ):

http://www.regulations. gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2007

- 1089

New Use of Quizalofop on DAS

- 40278

- 9 Corn
DAS

- 40278

- 9 corn is a GE corn line that has increased resistance to treatment with phenoxy auxin herbicides (e.g., 2,4

- D) and resistance to AOPP ACCase inhibitor (“fop”) herbicides ( DAS, 2010a )

. DAS has indicated that “fop” herbicides could be used to maintain seed purity in DAS

- 40278

- 9 corn breeding nurseries, hybrid production fields, and generally for the control of

Page 8

- 16grass weeds in corn. As q uizalofop is not currently registered for use as a post

- emergent herbicide on corn , this is a proposed new use ( DAS, 2010a )

. Quizalofop

- P ethyl is the active ingredient in DuPont Assure II TM herbicide (EPA Reg. No. 352

- 541). DuPont has submitted petitions to EPA to add the new use of quizalofop on DAS

- 40278

- 9 corn. Since most grass crops, including corn, are highly sensitive to the herbicide, quizalofop could only be used on field corn that has been GE to be resistant to the herbicide, such as DAS

40278

- 9 corn.

DuPont p roposes a maximum single application rate of 0.082 lb ai/acre corn ( DAS, 2011f ) . The proposed maximum application rate also is the seasonal maximum application rate ( DAS, 2011f ) . The proposed PHI is 30 days for forage; a PHI for corn grain or stover is not specified (US

- EPA, 2011). This maximum application rate is less than that currently approved by EPA for use of quizalofop for the control of grassy weeds in soybeans and cotton, where a seasonal maximum applic ation rate of 139 g ai/ha (0.124 lb ai/acre) is approved ( DAS, 2011f )

. Applications of quizalofop would be made by broadcast foliar application by ground; aerial applications would be prohibited. EPA currently is reviewing the propo sed label change for quizalofop and has not granted the registration yet. Table 8

- 6 provides a summary of the proposed application rates and directions for use on DAS

- 40278

- 9 corn.

Table 8

- 6

. Comparison of Current and Proposed Application Rates for Quizalofop

Crop Stage Current Use Pattern for Quizalofop on Soybeans and Cotton Proposed New Use on DAS

- 40278

- 9 Corn

Maximum Application Rate (lb/acre) 1,2 Directions and Timing Maximum Application Rate (lb/acre) 1,2 Directions and Timing

Post

emerg ence 0.082 Apply 0.034 to 0.082 lb/acre per application. Do not exceed a total of 0.124 lb/acre per season. 0.034 to 0.082 Apply 0.034 to 0.082 lb / acre per application from V2

– V6 Growth stages. Do not make more than 2 applications. Do not exceed a total of 0.082 lb/acre per season. Do not apply later than V6 growth stage. T otal Annual Maximum Application 0.124

--- 0.082

---

Source: ( DAS, 2011f )

. Notes: 1. Active ingredient. 2. 1 lb/acre is t he equivalent of 1,120 g/hectare.

Page 8

- 17Source: ( DAS, 2010b )

. Figure 8

- 3

. Proposed Quizalofop Application R ate on DAS

- 40278

- 9 Corn.

EPA Assessments of Proposed New Use of Quizalofop on DAS

- 40278

- 9 Corn

Environmental Fate and Ecological Risks As part of the approval process, EPA EFED performed a screening level ecological risk assessment for listed and non

- list ed species for the proposed label for quizalofop. The screening

- level analysis for quizalofop

- p

- ethyl concluded that the proposed new agricultural use for quizalofop shows the possibility for direct effects to mammals (chronic dose

- based risk), and
terres trial monocots. Direct risks were also assumed for aquatic vascular plants, and estuarine/marine fish (acute) because of an absence of data. Chronic risks were assumed for terrestrial birds because of nondefinitive toxicity endpoints. Since birds serve a s surrogates for terrestrial

- phase amphibians and reptiles, these taxa may also be at direct risk from the new uses of quizalofop

- p

- ethyl

. Indirect effects were determined by assessing the potential for reduction of prey base or habitat modification of li sted taxa. Given that monocots are at risk, there is the potential for habitat modification to indirectly affect all listed taxa.
The draft assessment will be published by EPA in the Federal Register for public review and
comment.

Human Health Risk Assess ment EPA HED evaluated hazard and exposure data , as well as dietary, residential (non

- occupational),

oc cupational , and aggregate e xposure s to estimate the risk to human health that could potentially

Page 8

- 18result from the proposed new use of quizalofop on DAS

- 402 78

- 9 corn . Based on the ir draft human health risk assessment, EPA HED recommends for a registration for the use of quizaolfop

on DAS

- 40278

- 9 corn . EPA identified additional data needed, specific tolerance recommendations, and label modifications. A summ ary of the results of the assessment are provided, below. The draft assessment will be published by EPA in the Federal Register for public review and comment.

Hazard Characterization: Quizalofop ethyl has low acute toxicities via the oral, dermal, and inhalation routes. It is not an eye or dermal irritant nor a skin sensitizer. Following oral administration, quizalofop ethyl is rapidly absorbed and excreted via urine and feces. Liver is the target organ as evidenced by increased liver weight and his topathological changes in the liver.

There were no effects observed in oral toxicity studies that could be attributable to a single

- dose exposure. Hence, a dose and endpoint have not been selected for assessment of acute exposure. Similarly, there was no observed toxicity in a dermal subchronic study at the highest dose tested (above the limit dose) so no dermal risk assessment is needed. Inhalation toxicity studies for occupational exposure assessment are waived based on the low exposure expected by the current and proposed use patterns. A chronic reference dose (cRfD) was established based on a combined chronic toxicity/carcinogenicity study in rats. Mutagenicity studies conducted on quizalofop ethyl did not demonstrate evidence of mutagenic potential . The Cancer Peer Review Committee determined that quizalofop ethyl should be classified as Category D (not classifiable as to human carcinogenicity). As such, a cancer risk assessment was not conducted.

Developmental studies in rats and rabbits and a two

- generation reproduction study in rats showed no evidence (qualitative or quantitative) for increased susceptibility following in utero and/or pre/post

- natal exposure to quizalofop ethyl.

Dietary Exposure and Risk Assessment: An acute dietary risk assessment was not performed, as an acute endpoint was not identified in the hazard assessment. Similarly no cancer risk assessment was needed, as quizalofop ethyl was not classifiable with regard to carcinogenici ty.
A chronic dietary exposure assessment was conducted using the maximum application rate per season for quizalofop ethyl on dry peas in Michigan. Under this scenario, children (1

- 2 years) were found to have the maximum chronic dietary risk at 29% of the chronic population adjusted dose (cPAD). This is well below HED’s level of concern of 100% of cPAD.

Residential Risk: Quizalofop ethyl has no registered homeowner or ornamental uses and none are being proposed.
Aggregate Risk Estimates: Aggregate risk es timates take into account dietary and non

- dietary residential sources of exposure. As there are no registered or proposed uses of quizalofop that would result in non

- dietary residential exposure, the aggregate risk estimates are equivalent to the chronic d ietary risk estimates discussed above and are below HED’s level of concern.

Occupational Exposure and Risk Assessment: No doses or endpoints for dermal or inhalation exposure were selected or needed. Therefore, a quantitative estimate of occupational risk was not

Page 8

- 19determined. The acute toxicity categories are IV for both routes of exposure, and a 12

- hour re

entry interval (REI) was established under the worker protection standard (WPS).

Glufosinate Ammonium Glufosinate is a contact herbicide which is taken up by the plant primarily through the leaves. There is no uptake from the soil through the roots, presumably because of the rapid degradation of glufosinate by soil microorganisms. There is limited translocation of glufosinate within the plant.

Glufosinat e is manufactured and labeled by Bayer Cropscience for pre

- plant burndown on conventional or GE soybean, corn, cotton, canola, or sugar beet and post

- emergence use on crops designated as LibertyLink TM (soybean, corn, cotton, canola, and rice). T he PAT prot ein
exp re ssed in DAS 68416

- 4 and DAS 44406

- 6 soybean soybean is similar to PAT found in other commercially

- grown glufosinate

- resistant crops (e.g., LibertyLink TM soybeans, corn, cotton, canola, rice) . Since the PAT protein has been included as an herbicide tolerance marker in products containing plant incorporated protectants ( PIP s) , it has been reviewed by EPA as a PIP inert ingredient ( US

- EPA, 2005a )

. Based on their environmental risk assessment, EPA determined that the PAT protein presents a low probability of risk to human health and the environment and granted an exemption from the requireme nt of a tolerance for this PIP inert ingredient (40 CFR 180.1151; 62 FR 17719, Aug. 11, 1997).

Based on pesticide usage data from USDA

- NASS, private pesticide market research, and California Department of Pesticide Regulation (DPR), EPA estimated gl ufosina te usage from 200 3 through 201 0 . The crops with the highest glyphosate uses (based on average treated fraction of acreage) were: almond ( 15 %), canola ( 25 %), grapes ( 15 %), and p istachios ( 20 %). All other treated crops averaged less than 15% of the total ac reage g rown ( US

- EPA, 2012d )

.
DAS has indicate d that the proposed glufosinate application rate for use on DAS

- 68416

- 4 soybean and DAS 44406

- 6 soybean will be consistent with the current use pattern of glufosinate on other glufosinate

- resistant soybean (i.e., LibertyLink TM soybean) ( DAS, 2010b ) . As there is

no change from the current EPA

- approved labeled use pat tern , no petition has been submitted to EPA for a change in the glufosinate label

. The EPA

- approved label for Liberty TM (i.e., glufosinate ammonium) use on glufosinate

- resistant soybean can be viewed here:
http://www.bayercropscience.us/products/herbicides/liberty/labels

- msds

The EPA

- registered use of glufosinate on LibertyLink TM soybean includes an in i tial burndown application of glufosinate no higher than 0.66 lb a.i./A (36 fl oz/A) with a minimum of 0. 53 lb a.i./A (2 9 fl oz/A). A single second in

- season application of glufosinate up to 0.53 lb a.i./A (29 fl oz/A) is approved on LibertyLink TM soybeans, with a seasonal maximum rate of 1.2 lb a.i./A (65 fl oz/A) permitted. Glufosinate applications on LibertyLink TM soybean should be made from emergence up to but not including the bloom growth stage and within 70 days of harvesting.

Pesticide residue tolerances for quizalofop are listed in 40 CFR Part 180.4 73 ( US

- EPA, 2012c )

. As quizalofop is not currently approved by EPA for use on corn, only residue limits for soybean commodities are shown in Table 8

- 7, representing combined residues of combined residues of quizalofop ethyl, quizalofop, and quizalofop methyl.

Page 8

- 20Table 8

- 7 . 2,4

- D Tolerances for Corn and Soybean Commodities
Commodity Residue (parts per million) Corn, field, forage 4.0
Corn, field, grain 0.20
Corn, field, stover 6.0
Soybean 2.0 Soybean, hulls 0.02 Source: §180.473 Glufosinate ammonium; tolerances for residues ( US

- EPA, 201 2c )

. Currently, glufosinate is undergoing registration review by EPA. The registration review began in 2008 and a decision is expected in 2013 ( US

- EPA, 2009a ) . EPAs web site for the glufosinate ammonium registration review case can be found here:
http://www.epa.gov/oppsrrd1/registration_review/glufosinate_ammonium/index.htm

The docket containing documents related to EPAs review can be viewed here:
http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2008

- 0190

Page 8

- 21References:

Burton, J.D., J.W. Gronwald, D.A. Somers, B.G. Gengenbach, and D.L. Wyse. 1989. "Inhibition of corn acetyl

- CoA carboxylase by cyclohexanedione and aryloxyphenoxypropionate herbicides." Pesticide Biochemistry and Physiology 34: 76

- 85.

DAS.2012a. "Dow AgroS ciences LLC Comments to Docket ID APHIS

- 2012

- 0019,." Section 2: Estimate of Herbicide Volume and Impact on Environmental Load of Herbicides with the Introduction of Enlist Soybean (DAS

- 68416

- 4) . 66.

DAS.2011a. "Enlist TM Weed Control System

- Technical Bulletin." Dow AgroSciences.

DAS. 2011b. Enlist TM Weed Control System

- Technical Bulletin

. DAS.2012b. "EnlistTM Weed Control System." PowerPoint Slide Deck presented June 11, 2012 to APHIS

- BRS and Louis Berger Inc. staff, . Ed. Blewett, T.C. 68.

DAS.2011c. "GF

- 2654 TS Draft Label." Supplemental Information for Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

- 68416

- 4 Soybeans

. Ed. Krieger, Mark S.: Dow AgroSciences LLC.

DAS.2011d. "Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

444Ø6

- 6 Soybean." Ed. Mark, S. Krieger: Dow AgroSciences. 228. http://www.aphis.usda.gov/brs/aphisdocs/11_23401p.pdf

.

DAS. 2010a. Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

40278

- 9 Corn. Submitted by L. Tagliani, Regulatory Leader, Regulatory Sciences & Government Affairs . Indianapolis, IN: Dow AgroSciences, LLC.

DAS.2010b. "Petition fo r Determination of Nonregulated Status for Herbicide Tolerant DAS

68416

- 4 Soybean." Ed. Mark, S. Krieger: Dow AgroSciences. http://www.aphis.usda.gov/biotechnology/not_reg.html

.

DAS.2012 c. "Preliminary Plant Pest Risk Assessment and Draft Environmental Assessment for Determination of Nonregulated Status of DAS

- 68416

- 4 Soybean Genetically Engineered for Herbicide Tolerance." 9/11/2012 ed: Dow Agrosciences. 66.

DAS.2011e. "Research Demonst rating Reduction in Potential Off

- Target Movement for 2,4

- D Choline and Colex

- D TM Technology as Part of the Enlist TM Weed Control System." Supplemental Information for Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

- 68416

- 4 Soy bean . 13.

DAS. 2011f. Supplemental Information for Petition for Determination of Nonregulated Status for Herbicide Tolerant DAS

- 40278

- 9 Corn; Regulatory Overview of 2,4

- D and Quizalofop Use on DAS

- 40278

- 9 Corn. Submitted by T.C. Blewett, Regulatory Leade r, Regulatory Sciences & Government Affairs. Indianapolis, IN: Dow AgroSciences, LLC.

Page 8

- 22Devine, M.D., and A. Shukla. 2000. "Altered target sites as a mechanism of herbicide resistance." Crop Protection 19: 881

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