UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460 

### APR 2

## 4 2013 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM

SUBJECT: BEAD's response to The Center For Food Safety comment onthe 2,4-D BEAD Chemical Profile. (DP# 409912) FROM: Bill Phillips, II,, Ph.D., Agronomist 

# Ay

THRU: Biological Analysis Branch 

# '}::(!1'1 J Sepehr Haddad, Environmental Protection Specialist

# /'It~**~** Science Information and Analysis Branch .,.. Derek Berwald, Ph.D., Economist Economic Analysis Branch Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Branch DiannSims

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

# ~**~** Economic Analysis Branch 

# \MJ \ Biological**an~** Economic Analysi Division 75 3P) TO: Garland Waleko Risk Management and Implementation Branch 2 Pesticide Re-evaluation Division

PRODUCT REVIEW PANEL: March 27,2013 Summary On February 12, 2013, The Center for Food Safety submitted to the Environmental Protection Agency (EPA) comments 

### inresponse to all docketed EPA documents regarding the registration review ofthe herbicide 2,4-D. Within The Center for Food Safety comment document (see Appendix A) there were statements specific to BEAD's chemical profile

1(BCP) 1 (see Appendix B). The focus ofthe statements was onthe analysis of2,4-D use data and its interpretation. BEAD would like to thank The Center for Food Safety for their comments related to the BEAD BCP for 2,4-D. Below are the BEAD responses to the comments provided by The Center for Food Safety.

The Center for Food Safety Comment: "BEAD also fails toprovide any agronomic explanation forpastchanges in 2,4-D use that it does record. For instance, BEAD data (Fable 2, p. 5) show substantial increases in 2,4-D use (bothpounds appliedandtotal acres treated) on soybeans, cotton andto a lesser extentcorn from the 2001-2005periodto the 2006-2010period. Since 2,4-D is.frequentlyrecommended to controlglyphosate-resistant (GR)weeds, andGR weeds have expandeddramatically over this timeperiodinpreciselythose three crops, these increases are very likely attributable to farmers making increasing use of 2,4-D to control GR weeds. Agronomically informed assessments of2,4-D usepatterns are criticalfor estimatingfuture use,for instance ifthe requestednew use applications are granted."

BEAD Response: BEAD agrees that agronomic assessments are important to future uses and new uses ofany pesticide. However, within the scope ofthe BEAD BCP the intent is to present information onthe use ofa pesticide in an effort to draw some inferences as to the importance ofthe role that a pesticide has played in pest control. In addition to evaluating the role ofa pesticide the BCP is also intended to inform the environmental and human health assessments ofcurrently labeled pesticide uses. As for past uses of2,4-D specifically, The Center for Food Safety is correct thatthere was an increase in 2,4-D use in soybeans and cottonbetweenthe 2001-2005 and

. 2006-2010 timeframes. It's also importantto note that the average total pounds and average total area treated for all uses actually decreased from the 2001-2005 timeframe (30 million pounds acid equivalent (a.e.) applied on 58 million acres) to (28 million pounds a.e. applied on 54 million acres) the 2006-2010 timeframe as was provided in a footnote to Table 2 ofthe document. While there were increases in 2,4-D use in soybean and cotton there are other crops for which use had increased minimally orhad decreased. In recent years the increase in the number ofbiotypes and the size ofeach population of glyphosate resistant weeds has led growers and applicators to look for herbicides that can take overwhere glyphosate has failed. It is certainly plausible that one ofthe herbicides selected to fit such a role would be 2,4-D. However, complicating the issue ofdetermining whether all or a majorportion ofthe national increase in 2,4-D use in some crops over the past is a direct result ofa single need is difficult due to the uncertainties with which herbicide decisions are

1 BEAD ChemicalProfile for Registration Review: 2,4-D Chemical Case, Biological and Economic Analysis. June 27,2012

2made. Any future evaluations of2,4-D use will need to look closely at such complexities in an attempt to conduct such an evaluation. BEAD did not address future uses inthe BCP because those uses for 2,4-D, inparticularthe Enlist herbicide/GE crop technology, as discussed in the comments are newuses for the choline salt of2,4-D. The proposed decision on the label amendment for these new uses will be going through a public process whereby environmental and human health assessments will be conducted and will focus onthe newuses of2,4-D choline. The Agency appreciates the details that were provided by The Center for Food Safety and an opportunity to provide additional information and comments will be made available during the public comment period for the 2,4-D choline salt herbicide label amendment.

3Appendix A 

### II. EPA'S ANALYSIS OF 2,4-D 

### USAGE EPAprovides an extremelybriefand inadequate analysis of2,4-D use in "BEAD: Chemical Profile for Registration Review: 2,4-D Chemical Case," hereinafterreferred to as "BEAD." As noted above, BEAD made no attempt to assess the changes in 2,4-D use that would be enabled by the proposed registrations for Enlist com and soybeans. BEAD also fails to provide any agronomic explanationfor past changes in 2,4-D use thatit does record. For instance, BEAD data (Table 2, p. 5) show substantial increases in 2,4-D use (both pounds applied and total acres treated) on soybeans, cotton and to a lesser extentcom from the 2001- 2005 period to the 2006-2010 period. Since 2,4-D is frequently recommendedto control glyphosate-resistant (GR)weeds, and GRweeds have expanded dramatically over this time period in preciselythose three crops, these increases are very likely attributable to farmers making increasing use of2,4-D to control GRweeds. Agronomicallyinformed assessments of2,4-D use patterns are critical for estimating future use, for instance ifthe requested new use applications are granted. 4 We note that Dow AgroSciences anticipates introduction of2,4-D-resistant corn in 2014, suggesting that it expects EPA to register 2,4-D choline salt for use on it before that time (Gillam 2013). CFS provides such informed analyses of2,4-D use patterns in Appendix B (pages 5-10) for soybeans and AppendixA (pages 6-13) for com and soybeans. Four critical aspects ofthese analyses deserve emphasis. First, Enlist com and soybeans eliminate, for all practical purposes, the biological constraint ofcrop injury thathas hitherto been a major factor limiting the extent, the frequency, and the intensity (lbs./acre) of2,4-D use inAmerican agriculture since its introductioninthe 1940s. Second, Enlist crops would facilitate a strong shift in 2,4- D use patterns, from predominantly early season use (pre-emergence) atpresentto midseason, post- emergence use, particularly on soybeans. The shift to post-emergenceherbicide use patterns is associated with increased drift-related crop injury episodes and more rapid evolution ofherbicide-resistant (HR) weeds. HRweeds in turn trigger greaterherbicide use as well as more tillage operations and associated soil erosion. Third, use ofEnlistcom and soybean systems will foster rapid evolution of2,4-D resistance in weeds already resistant to glyphosate and often other herbicides. Multiple HRweeds are already a huge and growing problem inU.S. agriculture, and will be greatly exacerbatedby Enlistcrops. Finally, only a renewed commitmentto much greater use ofnon-chemical weed controltactics inthe context oftruly Integrated Weed Managementcan slow the epidemic emergence ofherbicide resistance in weeds. Based onreasonable adoption scenarios and usage rates, CFS estimatesthat Enlist com and soybeans would each leadto roughly a 60-70 million lb./yearincrease in overall2,4-D use in American agriculture, comparedto a total of7 million lbs. used onboth com and soybeans at present. BEAD estimates that an average of28 million lbs. of2,4-D was applied each year in all ofU.S. agriculture from 2006-2010 (BEAD, p. 5-6), though this mightbe a slight underestimate since a few lower-use states are excluded. 21 million lbs. are applied to crops otherthan com or soybeans, and usage onthese crops may be expectedto continue at roughly similar levels. Once they are widely adopted, Enlist com and soybeans would leadto an estimated 120-140 million lbs. ofadditional2,4-D use, for 140 to 160 million lbs. total

4agricultural use ofthis herbicide. This would represent a five-fold increase in overall agricultural use of2,4-D. Dow's expected introductionof2,4-D-resistantcottonwould move increase usage still more. It should not be thoughtthatthis is an unrealistic scenario for herbicide use driven by an HR crop system and the resistant weeds it fosters. EPA estimated glyphosate usage, drivenby Roundup Ready crops and glyphosate-resistantweeds, at 180-185 million lbs. in 2007, and currentusage easily exceeds 200 million lbs. While glyphosate use with Roundup Ready crops significantly displaced use ofotherherbicides, a similarphenomenon is not expected with 2,4-D used with Enlist crop systems. This is because 2,4-D is a broadleafherbicidethat will be used primarily to kill glyphosate-resistantweeds, while broader-spectrum glyphosate will continue to be used inconjunction with it to kill grass-family weeds and others it controls more effectively. Additional analysis is presented in the usage analysis and resistant weed sections ofAppendices A and B.

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