UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

APR 2 3 20#.3 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: Responses to Public Comments Submitted by Syngenta Crop Protection, LLC. 

Concerning the Registration Review of Clodinafop-propargyl (PC Code 125203) 

from EPA Docket ID No. : EPA-HQ-OPP-2012-0424, DP# 409739 

FROM: 

THRU: 

Jihad Alsadek, PhD, Economist "' . T~~ ~--J+-.~ Science Information and Analysis Branch 

Bill Phillips, PhD, Agronomist AI j _,/ 

Biological Analysis Branch ~ 

Stephen Smearman, Economist 

Economic Analysis Branch 

Biological and Economic Analysis Division (7503P) 

Diann Sims, Chief /()~ Science Information and Analysis Branch 

Arnet Jones, Chief ;/) ~~~ Biological Analysis Branch ~I' u . 

Timothy 

Economic 

Kiely, 

Analysis 

Chief 

Branch 

Sl \A., ~ 

Biological and Economic Analysis ivision (75 

TO: Wilhelmena Livingston, Chemical Review Manager 

Risk Management and Implementation Branch 4 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel Date: April3, 2013 

Through this memo, BEAD i.s responding to comments submitted by Syngenta Crop Protection, 

LLC concerning the registration review of Clodinafop-propargyl. In addition to this response, 

BEAD is providing a revised version of the BEAD Chemical Profile for Clodinafop-propargyl 

(November 2012) which addresses several of the Syngenta comments. 

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Syngenta Comment 1: Syngenta believes the percent crop treated for wheat should be 7. 4% for 

average and 15.1% for maximum. 

BEAD Response: The Percen~ Crop Treated (PCT) values (5% for the average and 10% for the 

maximum) reflect the results of the Screening Level usage Analysis (SLUA) for clodinafoppropargyl. These values are derived from several pesticide usage data sources (USDA/NASS 

and EPA Proprietary Usage Data). These data are merged, averaged, and rounded for reporting 

purposes. We are not clear on the method used by Syngenta to derive the PCT values or the 

time frame represented in their data. No changes are suggested for the BEAD values. 

Syngenta Comment 2: Syngenta believes that the agricultural usage averaged approximately 

7 4, 000 pounds active ingredient (lbs. a. i.) on 6 million treated acres. 

BEAD Response: We are not clear on the data sources used to derive the Syngenta results and 

cannot confirm them. BEAD's reported values are based on proprietary data. Based on that 

data, the average annual pounds active ingredient (74,000 lbs. a.i.), and the average annual total 

area treated (1.8 million acres) are correct for the time period 2006-2010. No changes to BEAD 

values are suggested. 

Syngenta Comment 3: Syngenta respectfully submits that winter wheat accounted for 14% and 

spring wheat accounted for 76% of the wheat produced in Idaho, Montana and North Dakota. 

BEAD Response: BEAD ha.S removed this sentence in the BCP as it was confusing and did not 

provide additional supporting information to the fact that the majority of the durum wheat in the 

U.S. was harvested in the two states ofNorth Dakota and Montana. Overall, two sentences were 

removed because they were c~nfusing and did nothing to add to the focus of the paragraph. 

Original paragraph: 

Clodinafop-propargyl is primarily used in the northern wheat production areas of the country, 

concentrated mostly in the states of Idaho, Montana and North Dakota. The types of wheat 

produced in these states are durum wheat, hard red spring and winter wheat, and soft white 

spring and winter wheat. For the years 2006-2010, winter wheat accounted for an average of 

10% and spring wheat accounted for 72% of the wheat produced in Idaho, Montana and North 

Dakota. During this same time period, less than 5% of all wheat planted in the country included 

one of the spring wheat types such as durum. 70% of the durum wheat was planted in North 

Dakota with a smaller amount in Montana (20%). In 2010 and 2011, the average number of 

acres of durum wheat harvested by farmers in the states of Montana and North Dakota totaled 

89% of the nation's durum wheat grain harvest. 

Revised paragraph: 

Clodinafop-propargyl is primarily used in the northern wheat production areas of the country, 

concentrated mostly in the states of Idaho, Montana and North Dakota. The types of wheat 

produced in these states are durum wheat, hard red spring and winter wheat, and soft white 

spring and winter wheat. Seventy percent of the durum wheat was planted in North Dakota with 

a smaller amount in Montana(20%). In 2010 and 2011, the average number of acres ofdurum 

wheat harvested by farmers in the states of Montana and North Dakota totaled 89% of the 

nation's durum wheat grain harvest. 

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Syngenta Comment 4: Syngenta respectfully submits that c/odinafop-propargyl was applied to 

93% of the total acres treated (FAT) while 9% of the lbs. a.i. had been applied to 7% of the 

different types of winter wheat. . . 

BEAD Response: BEAD agrees to this revision and has changed the percentages in the revised 

version of the BCP. The difference was due to rounding error in the BEAD calculation. 

Syngenta Comment 5: Syngenta would like to respectfully revise foliar to foliar, postemergence. 

BEAD Response: BEAD agrees to this revision. Clodinafop-propargyl is a systemic, postemergence herbicide for selected grass control in spring and durum wheat. These changes are 

addressed in the revised BEAD Chemical Profile for Clodinafop-propargyl (March 26, 2013). 

Syngenta Comment 6: The maximum application rate for Discover Herbicide (EPA Reg. No. 

100-907) is 4 jl oz/A, and the active ingredient (a.i.) maximum application rate for Discover 

Herbicide (EPA Reg. No. 1 00-907) is 0. 0625 lb/A. 

BEAD Response: BEAD agrees that the Discover herbicide label does show that 4 fluid ounces 

per acre is the labeled maximum application rate for this product in a minimum of 5 gallons of 

water or aerially in a minimwn of3 gallons of water per acre combined with 12.8 ounces ofDSV 

adjuvant. The dosage conversion system in BEAD's label use reports does not provide 

converted active ingredient (a.i.) rates for tank mixes including surfactant and adjuvant mixtures. 

As such, the maximum converted rate for this product was captured as No Dosage Conversion 

(NDC) in the converted single maximum application fields of the Clodinafop-propargyl 

Appendix A and EFED Label Data report. BEAD agrees with Syngenta that the converted single 

maximum application rate is 0.0625 lb. a.i. /A. 

Sources: 

Clodinafop-propargyl Screening Level Usage Analysis (SLUA), EPA-HQ-OPP-2012-0424-0004 

Appendix A, EFED Label Data report 

B. Phillips, J. Alsadek, and S. Smeannan Clodinafop-propargyl BCP, March 26, 2013 

Syngenta Crop Protection, LLC. Comments Submitted by Syngenta Crop Protection, LLC. 

Concerning the Registration Review ofClodinafop-propargyl (PC Code 125203) from EPA 

Docket ID No.: EPA-HQ-OPP-21012-0424, February 8, 2013 

B. Phillips, J. Alsadek, and S. Smeannan. Responses to Public Comments Submitted by 

Syngenta Crop Protection, LLC. Concerning the Registration Review of Clodinafop-propargyl 

(PC Code 125203) from EPA Docket ID No.: EPA-HQ-OPP-21012-0424 

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