UNITED STATES**ENVIRON~ENTAL** PROTECTION AGENCY WASHINGTON, D
.C
. 20460 

### NOV 0 1

## 2012

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### SUBJECT: FROM: BEAD Chemical Profile for Registration Review: Clodinafop-propargyl (125203)
Bill Phillips, Ph.D., Agronomistt1Jf{ Biological Analysis Branch

### ~

THRU: Jihad Alsadek, Economist

# ~~ A--

# l'f->~ Science Information and Analysis Branch Stephen Smearrnan, Economist

# J

# ~ 4 

# f ··· -- Economic Analysis Branch

## ~~ . Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Branc Diann Sims, Chief

# ~ Science Information and Analysis Branch



## ... Timothy Kiely, Chief 1 

### Economic Analysis Branch q 

## 1M,. \ Biological and Economic Analysis Division (7503P) TO: Wihelmena Livingston, Chemical Review Manager Risk Management and Implementation Branch 4 Pesticide Re-evaluation Division (7508P) 

### ProductReview Panel date: August 01, 2012 

### Introduction The purpose ofthis document is to convey usage information and a broad overview ofthe pest management roles ofpesticides that are beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status ofclodinafop-propargyl, and eventually the general public. This document builds upon the data already provided in the "Usage and Label Use DataPackages" that are also provided to 1Registration Review teams by BEAD. The document is based on information and data available to BEAD as ofAugust 01,2012. 

### Herbicide Discussion Clodinafop-propargyl is a postemergence herbicide formulated as an emulsifiable concentrate and used to control annual and perennial grasses. When mixed with the chemical safener cloquintocet-mexyl this herbicide canbe tolerated by wheat and still provide effective weed control. This herbicide is inthe Weed Science Society group 1 and has a mechanism ofaction of inhibiting fatty acid synthesis by the inhibition ofthe enzyme acetyl-CoA carboxylase (ACCase). This herbicide controls some economically key weed species that impactcrop production, specific weed species are, green foxtail 

### (Setaria viridis), yellow foxtail 

### (Setaria glauca), and giant foxtail 

### (Setaria faben) as well as barnyardgrass 

### (Echinochloa crus-galli). Currently there are 2 weed biotypes that are resistant to this herbicide, wild oats 

### (Avenafatus) and Italian ryegrass 

### (Lolium multiflorum). In addition to their resistance to clodinafop-propargyl these biotypes are also resistant to other Group 1 herbicides. Careful stewardship ofthis herbicide and other Group 1herbicides is needed inorderto reduce the selection ofother resistant biotypes and to maintain this herbicide chemistry. Clodinafop-propargyl is primarily used in the northern wheat production areas ofthe country, concentrated mostly in the states ofldaho, Montana and North Dakota. The types ofwheat produced inthese states are durum wheat, hardred spring and winter wheat, and soft white spring and winterwheat. Forthe years 2006-2010, winterwheat accounted for an average of 10% and spring wheat accounted for 72% ofthe wheatproduced in Idaho, Montana andNorth Dakota. Duringthis same time period, less than 5% ofall wheat planted in the country included one ofthe spring wheat types such as durum. 70% ofthe durum wheat was planted inNorth Dakota with a smaller amount in Montana (20%). 1 In 2010 and 2011, the average number of acres ofdurum wheat harvested by farmers inthe states ofMontana and NorthDakotatotaled 89% ofthe nation's durum wheat grain harvest. From 2006-2012, 90% ofthe totallbs a.i. ofclodinafop-propargyl was applied to 90% ofthe total acres treated (TAT) for the various types ofspring wheat; while 9% ofthe lbs a.i. had been applied to 8% ofthe different types ofwinter wheat? From 2006-2010, the annual total agricultural usage averaged approximately 74,000 pounds active ingredient (lbs a.i.) on 1.8 million treated acres (approximately 3.75% ofthe total US harvested wheat acreage) with an average application rate of0.04lbs. a.i. acre· 1

. On average, for the years from 2006 to 2010, Montana and North Dakota farmers together accounted for 83% ofthetotallbs ai ofClodinafop-propargyl used on 90% ofthe durum crop produced in the nation. This niche market for this herbicide is very important in spite ofthe relatively lowtotal national use of74,000 pounds active ingredient.

1 USDA, National Agricultural Statistics Service. July 2011. http://www.usda.mannlib.eomell.edu/usda/nass/CropProd-07-12-2011.pdf 2 EPA Proprietary Data, 2006-2010 2

### The climate in the two states, Montana andNorth Dakota, where clodinafop-propargyl herbicide is currently being used the most are characterized by very cold winters with an average annual rainfall of 

### go inches3 

### and an average soil organic matter oflessthan or equal to three percent4• 

### Given the soil organic matter in the states and the short soil half-life (<3 days), as well as the relatively high 

## Koc (1,500-2,000) ofthis herbicide5
, 

### carryoverto rotated crops may not be an issue. 

### Use Trend Summary Overall, the crops with most total areatreated (TAT) are spring wheat (90%), winter wheat (9%), and barley and fallow (<1 %). 

### However, the use ofclodinafop-propargyl has declined since its peak in2005, when use is averaged over all reported crops. Figure 1presents the trend ofuse for clodinafop-propargyl interms oftotal pounds.
Figure 1. 

### Total Annual Agric.ultural Usage for Clodinafop-propargyl between 2000-2010

180,000 .-------------------- --------



### <i Ill "D c :I 0 Q..

2000 2001
. 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years Source: Proprietary Data, 2000 -2010 

### Figure 2 provides usage data for 2006-2010. During this period, the use ofclodinafop-propargyl on spring wheat increased in 2008 and had a slight decrease in 2009. The use onwinter wheat was also fairly steady except for a decrease in 2007 and 2010. There could be many factors that played into these use fluctuations, however there does not seem to be a single verifiable reason.

3 http:/ /www.nass.usda.gov/Charts _and_ Maps/Crops_ County/index.asp#cr 4 Flaherty, C. "What is a pound ofnitrogen worth in spring wheat
. MSU Communications Services, Bozeman, MT 59717http://www.montana.edu/cpa/news/wwwpb-archives/ag/whe _fert.html 5 Vencill, W.K. ed. Herbicide Handbook, Eighth Edition. 2002. Weed Science Society ofAmerica. Lawrence, KS 66044
. USA 

### 3Figure 2. Agricultural Usage Datafor Clodinafop-propargyl averaged over 2006-2010. 100,000 ..--- --- -- -- ---------

2006 2007 2008 Years Source: Proprietary Data, 2006-2010 History ofBEAD assessments - Wheat, Spring

- Wheat, Winter

2009 2010

BEAD conducted an assessment for clodinfop-propargyl for EPA's Registration Division in 2010. A document entitled "Requested Information on FourHerbicides Used for Weed Control in Wheat Production" was a review bythe Bioloigical and Economic Analysis Division (BEAD) to provide information on four herbicides (flucarbazone-sodium, pinoxaden, clodinafoppropargyl, and pyroxsulam) used for weed control in wheat production. This information was needed for RD to resolve a risk issue involved with safeners used in these herbicide formulations. To support the process, BEAD reviewed publicly available information related to application rates, application timing, mechanism ofaction and major weeds controlled by these herbicides.**~EAD** concluded that all four ofthese herbicides would not be applied to the same wheat field inthe same production season. BEAD did conclude that onvery rare occasions, sequential application of2-3 ofthese herbicides is possible depending onthe weed spectrum and intensity ofweed pressure found in an individual wheat field in a particular growing season. Conclusion Overall the use ofclodinafop-propargyl in Idaho, Montana, andNorth Dakota is important for the control ofannual and perennial grasses. As discussed earlier inthis document, because ofthe magnitude ofthe use in Montana and North Dakota where 89% ofthe harvested durum wheat produced inthe US accounted for 83% ofthe clodinafop-propargyl use, it is clearthat there is an important niche use for this herbicide.

4

### References Proprietary Data, 2000-201 0 USDA, 2006-2010. NASS Crop Reporting Districts. Online: http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass
. USDA, 2007. Census ofAgriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp
. USDA, 2012. National Agricultural Statistics Service, Crop Production, Agricultural Prices, and unpublished data; and USDA, World Agricultural Outlook Board, World Agricultural Supply and Demand Estimates
. Online: http://www.ers.usda.gov/data-products/wheat-data
.aspx.

5APPENDIX Clodinafop-propargyl Usage 

### by Crop Reporting District 

### (2006- 2010) Another measure ofusage is the use intensity. Inthis analysis, the use intensity is expressed as the pounds a.i. applied per acre ofland in farms. This differs from the application rate, which is expressed as the pounds a.i. applied pertreated acre. Figure 3 spatially represents clodinafop-propargyl's use intensity inthe US.

Clodinafop-propargyl Use (2006-2010) by Crop Reporti ng District Av0f118e Pounds per 1,000 Acres ofFarmland

- <0
. 11

. 0
.11

- 0
.25 CJ0
.26

- 0
.50 0
.51-2.00

. 2
.01

- 2.50
This is a map ofagricultural pesticide usage at the Crop Reporting District (CRD) level prepared by BEAD for use in the Environmental Fate and Effects Division documents. These maps are used to help visualize where the pesticide being considered is most likely to be used and can be helpful in scenario selection and placing the exposure assessment in context. CRDs are boundaries created by USDA NASS which are aggregates ofcounties (USDA, 2010). Pesticide usage is displayed as average pouhds (for the years 2006-2010) per 1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. Farmland acreage was obtained from USDA (2007). Farmland or "land in farms" is defmed as follows: The acreage designated as "land in farms" consists primarily of agricultural land used for crops, pasture, or grazing. It also includes woodland and wasteland not actually under cultivation or used for pasture or grazing, provided it was part ofthe farm operator's total operation. Large acreages ofwoodland or wasteland held for nonagricultural purposes were deleted from individual reports during the edit process. Land in farms includes CRP, WRP, FWP, and CREP acres. Land in farms is an operating unit concept and includes land owned and operated as well as land rented from others. Land used rent free was reported as land rented from others. All grazing land, except land used under government permits on a per-head basis, was included as "land in farms" provided it was part ofa farm or ranch. Land under the exclusive use ofa grazing association was reported by the grazing association and included as land in farms. All land in American Indian reservations used for growing crops, grazing livestock, or the potential of grazing livestock was included as 6land in farms. Land in reservations not reported by reservation, individual American Indians or non-Native Americans was reported in the name ofthe cooperative group that used the land. In many instances, an entire American Indian reservation was reported as one farm (2007 Census of Agriculture, USDA). Usage is based on private market surveys ofpesticide use in agriculture (Proprietary Data, 2006-2010). The survey data are limited to the states that represent the top 80-90% ofacreage for the individual crops, therefore, use may be occurring in regions outside the scope ofthe survey. CRDs showing no usage ofpesticides may be due to either the lack ofpesticide use in the region or non-participation in the agricultural surveys. In addition, across the years, there may be variations in the specific crops included in the CRD survey. This may result in a lower annual average for the CRD. This map displays ratio data (i
.e., average pounds per 1,000 acres offarmland) summarized at a very high-level. Readers are strongly cautioned against trying to over interpret the map without examination ofthe underlying data. The underlying data may explain some ofthe many reasons that a Crop Reporting District may have a high value for a particular active ingredient such as significant acreage (compared with the CRD as a whole) ofa crop or crops with a high application rate and frequency ofapplication. The reader should pay particular attention to the figure legends and realize that a map prepared for a particular chemical is not directly comparable to a map prepared for a different chemical. Scale and units ofmeasurement do matter and may be different between maps. Sources: Proprietary Data. 2006-2010 USDA, 2006-2010
.NASS Crop Reporting Districts
. http://www.ers
.usda
.gov/briefing/arms/resourceregions/ resourceregions.htm#nass
. USDA, 2007. Census ofAgriculture. http://www.agcensus.usda.gov/Publications/2007/index.asp
.



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