UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D

.C., 20460 

### FEB 06**~** 

### '.l

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### SUBJECT: Response to Public Comments from the Center for Food Safety and Bayer Crop Science onthe Glufosinate Draft Risk Assessments, DocketNo. EPA-HQ-OPP2008-0190 FROM:

THRU: William Chism, Senior Biologist Biological Analysis Branch Cynthia Doucoure, Environmental Protection Specialist Science Information and Analysis Branch (SlAB) Derek Berwald, Economist 

### k { 

## r'l"\-**(M_~** Economic Analysis Branch ' 

## J v '-.1 ) 

### Biological and Economic Analysis Division (7503P) Amet "Skee"Jones, Chief

# ~~ Biological Analysis Branch

. /

# u,)

Diann Sims, Chief

# a~ Science Information and Analysis Branch Timothy Kiely, Chief 

# QJ.\

..**~** Economic Analysis Branch \M..... 

### Biological and Economic Analysis ranch (7 P TO: Shirley Keel, Acting Team Leader Risk Management and ImplementationBranchV Pesticide Re-evaluation Division (7508P)



### ProductReview Panel Date: September25, 2013
Throughthis memo, BEAD is providing responses to comments on glufosinate usage data submitted by the Center for Food Safety (CPS) and Bayer Crop Science (BCS) intheir May 6, Page l of 72013 submissions to OPP inresponse to the Glufosinate Draft Risk Assessment, DocketNo. EPA-HQ-OPP-2008-0190. The CFS and BCS comments below are verbatim as received in the submissions

. 

### Center for Food Safety (CSF) Comments
IV. EPA'sASSESSMENT OF GLUFOSINATE USAGE 

### CFS Comment BEAD shows a total of2.24 million lbs. ofglufosinate applied to 21 crops in additionto fallow land in its updated Screening Level Usage Estimate (SLUA, p. 2). This estimate is based on data from various sources dated 2003 to 2010, which are thus from 3-10 years old (SLUA, p. 1). The majority ofcrops listed by BEAD are orchard crops, fruit and nut trees. This reflects glufosinate's historical use pattern: small-acreage specialty crops concentrated in states like California and Oregon where orchards are prevalent. While glufosinate will likely continue to be used in these settings, these specialty crops represent only 24% ofoverall glufosinate use, or 0.54 million lbs.
In contrast,justfour large-acreage field crops (canola, com, cotton and soybeans) claim 76% of overall glufosinate use (1.7 million lbs.). All ornearly all ofthis 1.7 million lbs. is attributable to glufosinate-resistant varieties. This is true despite the fact that glufosinate-resistant crop adoption is extremely low (just a few percent) for com and soybeans, and 5-10% for cotton. The extremely large acreage planted to these crops means thatthe glufosinate applied to eventhe tiny proportion that is glufosinate-resistantpredominates overthat used onmuch smaller acreage orchard crops. Glufosinate use is surging due to several well-documented developments. First, glyphosateresistant (GR) weeds are continuing to infest ever more cropland, and use ofglufosinate with glufosinate-resistant varieties is one ofthe majorrecommendations being made bypesticide-seed firms and extension agents as a response to the epidemic. Second, there is rapidly increasing availability and adoption ofglufosinate-resistant field crops, driven primarily by GR weeds. These factors ensure a continuation ofthe ongoing and dramatic rise in glufosinate use to a level that is several to many times that estimated by BEAD injustthe next few years, perhaps even before the registration review is complete. Below, we explain these developments, and then provide a realistic assessment ofglufosinate use informed bythese developments. According to a three-year survey ofglyphosate-resistantweeds in 31 states by the agri-marketing firm Stratus, 49% offarmers surveyed in 2012 had glyphosate-resistant weeds ontheir farm, up from 34% offarmers in 20**11~** 61.2 million acres ofcropland are nowinfested by GRweeds; GR weeds are rapidly expanding inthe Midwest; and ever more farmers report two ormore resistant species ontheir farms (Stratus 2013). The weed science communityhas reported onthis development many times, and it is indisputable that GR weeds continue to infest more and more cropland. Dowlikewise reports 60 million acres ofcropland infested by GR weeds (Bomgardner 2012), while Ian Heap, who manages the International Survey ofHerbicide:-Resistant Weeds, estimates somewhat less, 30-40 million acres (Heap 2012). Page 2 of 7BEAD Response We agree that the small acreage specialty crops account for**~** 24% andthe large acreage field crops claim**~**76% ofthe overall glufosinate use. We also agree that usage ofglufosinate inthe U.S. is increasing and is likelyto continue to increase inthe future. The Screening Level Usage Analysis (SLUA) provides average usage estimates ofa specific chemical onregistered crops over several years. This information is often used to characterize use ofthe chemical. However, BEAD also produces analyses that take into account trends in chemical use. Our available market datafor glufosinate supports the surge in glufosinate as described above. The additional information youprovided that document reasons for the surge is greatly appreciated.

CFSComment Thus far, GR weeds have caused the most economic and agronomic damage in cotton. Glufosinate-resistant cotton adoption has increased sharply as GRPalmer amaranth and horseweed and other GRweeds undermine the effectiveness ofa glyphosate-based weed control program. The latest data from USDA's Agricultural Marketing Service suggests thatroughly 24% ofthe nation's cotton acres were plantedto varieties resistant to glufosinate herbicide (USDA AMS 2012). Only 6% ofcottonplanted represents LibertyLink varieties from Bayer CropScience, which are marketed as resistant to glufosinate; the other 18% are Phytogen Widestrike cotton varieties, which incorporate glufosinate-resistance in the form ofa resistance marker gene. Though not advertised as glufosinate-resistant, cotton growers have learned that it is and often apply glufosinate to these crops to kill glyphosate-resistant weeds (Golden 2010). The latest figures from USDANASS's Agricultural Chemical Usage survey showthat 333,000 lbs. ofglufosinate were applied to Program State cotton acres in 2010/5which represent 84.5% oftotal cotton acres planted in the US; correction for the unsurveyed 15.5% yieldsjustunder 400,000 lbs. ofglufosinate applied to cotton (333,000/0.845). BEAD Response BEAD agrees thatthe 2010 estimates ofpounds ofglufosinate applied to cottonprovided by CFS exceed the amount provided on the SLUA. However, as a reminder, BEAD did notjust look at one year ofdata but averages available usage data over 7 to 8 years. The average pounds ofglufosinate applied to cotton during the 2003 to 2010 period was 200,000 lbs a.i. and the average PCTwas 5%.

CFS Comment GR weeds have also become a huge problem for many soybean growers. Glufosinate-resistant soybeans were first made available to farmers in 2009, despite deregulation in 1996. Dowreports proprietary dataon glufosinate-resistant soybean adoption and associated glufosinate use that is summarized in the table below.

Page 3 of 7Year Glufosinate- Total Glufosinate- Pounds Pounds Resistant Soy Soybean Resistant Glufosinate Glufosinate per as 9'0 Total Soy Acres Soybean Acres Applied (a.i.) Acre (a.i.) Acres (thousands) lthousands) 2009 < 19'0 77,451 71,718 2010 1.19'0 77,404 851 460,026 0.54 2011 1.39'0 75,208 978 556,775 0.57 Source: Dow (20 11). "Supplementary documentallon tn support ofdraft enVlronmental assessment: Glufosmate use on soybeans," DowAgroSciences, Nov. 115, 2011; USDA NASS for soybean acreage figures. Glufosinate use on soybeansjumped nearly eight-fold injustthe two years from 2009 to 2011, tracking the rapid increase in glufosinate-resistant soybean acreage. Though applied tojust 1.3% ofsoybean acres, soybeans represent the second-highest use ofthe herbicide (over 500,000 lbs.), second only to com. 

### BEAD Response BEAD agrees that use ofglufosinate on soybeans hasjumped nearly eight-fold injustthe three years from 2009 to 2011.



### CFS Comment Glyphosate-resistant weeds have not yet become as problematic or extensive in com as in soybeans orcotton, though reports have been on the rise since 2005. Accordingly, glufosinateresistant comhas notbeen widely adopted, and glufosinate has only been employed to a limited extent oncomresistant to it. EPA reports glufosinate applied to an average of5% ofcom acres and a maximum of 10%, which would also reflect glufosinate-resistant com acreage since glufosinate can only be usedpost-emergence with glufosinate-resistant varieties, and glufosinate is used little ifat all pre-emergence since there are better and cheaper pre-emergence herbicide options in com. Assuming deregulation by USDA, DuPont-Pioneer will be introducing comhybrids based on 4114 maize, which will incorporate both glufosinate- and glyphosate-resistance as well as resistance to lepidopteran pests and comrootworm (Appendix, p. 27). DuPont-Pioneer expects to more efficiently develop glufosinate-resistant comvarieties based on4114 maize, which should mean more rapid development ofmultiple highly-stacked comvarieties that containthis trait and retirement ofmore affordable varieties with few or no biotech traits (Appendix, p. 46). This increased availability coupled withrapid emergence ofglyphosate-resistant weed biotypes in com since 2005 ensures a trend ofsharply increasing glufosinate use in com as well. Increasing use driven primarily by glufosinate-resistant crops has led to "all-time high" in demand for glufosinate (trade name: Liberty), as explained by a Bayer spokesman below: "Bayer Spokesman AI Luke says, 'Due to the increased pressure ofglyphosate resistant weeds and the use ofLiberty herbicide inboth LibertyLink andnon-LibertyLink crops, demand for Liberty herbicide has reached an all-time high. Although Bayer CropScience has dramatically

. fage 4 of 7increased production quantities ofLiberty for the 2012 crop season, some local areas may face challenges in locating supply."' (Roberson 2012) In light ofthis analysis, it is clear thatEPA has underestimated current glufosinate use associated with glufosinate-resistant crops, and made no allowance for cleartrends that are driving increased use. For instance, EPA reports 100,000 lbs. ofglufosinate applied to soybeans (SLUA), in contrastto the more than 500,000 lbs. reported by Dow (2011). BEAD's estimate of 200,000 lbs. ofglufosinate on cotton (SLUA) is only halfthe 2010 usage of400,000 lbs., and glufosinate use oncotton has surely increased since then. However, currentuse does not capture well-delineated trends that EPA should account for. In the table below, CFS provides a projection ofglufosinate use under various scenarios. 

### ProJection ofGlufoslnateUse on Glufosinate-ReslstantCrops Crop Rate' Total Crop Annual Use rn Four Different Scenarfos: (a.l./acre/year) Acru + current use, 10%, 25%, SO% Crop Acres (millions) Treated {million lbs. a.l.) Current 10% 2S% SO%

Use"' Corn 0.51b. 100 2.5 5.0 12.5 25.0 Cotton 0.61b. 12 0.5 0.7 1.8 3.6 Soybeans 0.61b. 75 0.6 4.5 11.3 22.5

TOTAL 3.6 10.2 25.6 51.1 # Slightly higherthancurrentusagerates m each ca$e, to account for creepmgglufosmatereSistance, although any signifi.cant emergence ofglufo sinate-resistant weedswould increase use rates morethan indicated here. + Based on extrapolation ofcurrent acreage trends • So/o com (BEAD); 7% cotton (USDA NASS 2010), I 3% soybeans (Dow estimate for 2011) In light ofthe above discussion, the scenario projecting 10% total com, cotton and soybean acres treated with glufosinate is a conservative projection ofcurrenttrendsjusta few years into the future. In this scenario, 10.2 million lbs. glufosinate would be applied to these three crops and 10.7 million lbs. total, assumingthe other, primarily orchard crop uses remain at 0.5 million lbs. This conservative scenario would represent nearly a five-fold increase in glufosinate use over the 2.24 million lbs. estimated by BEAD. Glufosinate treatment of50% ofcotton acres and 25% of soybean acres is certainly conceivable inthe near future in light ofglyphosate-resistant weed pressure inthese crops, which would mean annual use ofapproximately 20 million lbs. glufosinate. Practically all ofthis vastly increased use would be post-emergence applications to field crops in areas (e.g. Midwest, Northern Plains, mid-South) where glufosinate is used sparingly at present.

BEAD Response BEAD agrees that use ofglufosinate on cotton and soybeans has increased, especially over the mostrecent three years and that increased use is likely to continue. As for com, BEAD finds that, based on the available data, there was a sharp increase in glufosinate usage from 2005 to 2007; however, after 2007, there was a sharp decline in usage in terms ofpounds ofglufosinate Page 5 of 7applied and total areatreated.

V. GLUFOSINATE-RESISTANT CROPS, WEEDS. AND VOLUNTEER WEEDS 

### CFSComment CFS provides a documented discussion ofthe problem ofglufosinate- and multiple herbicideresistantweeds as they relate to glufosinate-resistant crops in the Appendix (pp. 14-28). A documented discussion ofwhy herbicide-resistant crop systems foster more rapid evolution of resistant weeds is found inthe Appendix, pp. 17-20, while the highpotential for glufosinateresistant weeds is addressed onpages 20-25. One important issue here is the discovery ofa weed biotype that had evolved resistance to glyphosate through continual glyphosate use, butwhich has also been found to be resistant to glufosinate, an "alarming weed management issue" that casts great doubt onthe strategy ofusing POST glufosinate to kill glyphosate-resistant weeds on crops resistant to both herbicides, and more generally on the "multiple modes ofaction" dogma as the chiefrecommendation to forestall or manage herbicide-resistant weeds. The high potential for already multiple herbicide-resistant weeds (e.g. waterhemp) to rapidly evolve resistance to glyphosate is also discussed. EPA should be interested in how glufosinate- and multiple herbicide-resistant crop volunteers can accelerate evolution ofresistance in pests such as the com rootworm, whenthose HR crops also express Btinsecticidal toxins (Appendix, pp. 27-28). 

### BEAD Response The use ofany pesticide can lead toincreased selectionpressure for resistantpests. Historically glufosinate, which was registered in 1993 inthe U.S., has not had a severe problem with resistant weeds and there is only one weed species Italian ryegrass found in the United States that is resistant to glufosinate (Heap, I. The International Survey ofHerbicide Resistant Weeds. Online. Internet. Wednesday, October 30,2013. Available www.weedscience.org). The EPA, Office ofPesticide Program (OPP) is concerned about pesticide resistance and is actively working on a wide range ofresistance issues. OPP- has a voluntary program (the Food and Drug Administration also has voluntary programs for antibiotics and anthelmintics) for resistance managementthat is described in our Pesticide RegistrationNotice 97-2. The program is updating that PRNotice onresistance management. Itis developing a webpage ofdefinitions and frequently asked questions. And it is working with registrants to putthe mode ofaction and resistance management language ontheirpesticide labels. OPP has been working with the Fungicide, Herbicide and Insecticide Resistance Action Committees (FRAC, HRAC, and IRAC) as well has a professional societies (Agronomy, Entomology, Plant Pathology, Weed), and crop consultants (National Assoc Ind. Crop Consultants & Certified Crop Consultants). HRAC and the Weed Science Society ofAmericahave provided a list ofBestManagement Practices for resistance management which couldbe used as a template for farmers to develop their own herbicide resistance plan. The best managementpractices take a very holistic approach (e.g. crop rotation, mechanical weed control, scouting and identification ofweeds, etc.) and only a few ofthe elements can be directly addressed bypesticide regulations.

Page 6 of 7

### Bayer Crop Science Comments



## - Glufosinate Typical Use Data, DP #405082, Document EPA-OPP-2008-0190-0030, dated September 17, 2012 Bayer Comment EPA indicates there is no active registration for peaches, plums orprunes. Glufosinate use on these crops was registered Sept 27, 2012. Please refer to Appendices 1 and 2 for the maximum application rates and number ofapplications for all listed crops. Please refer to Table 1 for the total area (in acres) treated and maximum application rate (lb a.i./acre) for the years 2010- 2012 for the crops listed.

BEAD Response We appreciate the update on the registration ofpeaches and plums/prunes and for the data.
Bayer Comment Informationpresented in Appendices 1 and 2 provides the currently registered use scenarios by crop as perthe label directions on the current labels for Liberty® 280 SL Herbicide (EPA Reg. No. 264-829), Liberty® 200 SL Herbicide (EPA Reg. No. 264-660) and Finale® Herbicide (EPA Reg. No. 432-1229), Derringer Herbicide (432-1228) and Derringer F Herbicide (432-960) for non-crop weed control and weed control in conifer and hardwood tree plantings. BEAD Response Thanks for the dataprovided for currently registered uses ofthe above mentioned products.

Page 7 of 7