UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C

. 20460 

## APR J 

## 32013

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### MEMORANDUM
SUBJECT:

FROM:

THRU: 

### BEAD Chemical Profile (BCP) for Registration Review: Clodinafop-propargyl (125203)
Bill Phillips, Ph.D.,

## Agronomist~ Biological Analysis Branch

### ~ Jihad Alsadek, Ph.D., Economist

# .;r~**~ /If~**  Science Information and Analysis Branch Stephen Smearman, Economist ./._ -1_. _ 

### 1 Economic Analysis Branch ;IJG!f-'I.VVI**~** 

### Biological and Economic Analysis Division (7503P) Arnet Jones, Chief Biological Analysis Bran<(b 

### /)

Diann Sims, Chief

## /.-.!J(_£1...,.,_~~'1V'""'-" Science Information and Analysis Branch Timothy Kiely, Chief

# ~ lA

# ~ Economic Analysis Branch 

## U 

## !.) VV'-._, 

### Biological and Economic Analysis Division (750 TO: 

### Wihelmena Livingston, Chemical Review Manager Risk Management and Implementation Branch 4 Pesticide Re-evaluation Division (7508P)
Product Review Panel date: 

### August 01, 2012 Revised: 

### March 26, 2013 Introduction 

### The purpose ofthis document is to convey usage information and a broad overview ofthe pest management roles ofclodinafop-propargyl that is beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status1

### ofclodinafop-propargyl, and e.ventually the general public. This document builds upon the data already provided in the "usage and label use data packages" that are also provided to Registration Review teams by BEAD. The document is based on information and data available to BEAD as ofMarch 26, 2013. Herbicide Discussion 

### Clodinafop-propargyl is a systemic, postemergence herbicide formulated as an emulsifiable concentrate and used for selected grass control in spring and durum wheat. When mixed with the chemical safener cloquintocet-mexyl this herbicide can be tolerated by wheat and still provides effective weed control. This herbicide is in the Weed Science Society group 1 and has a mechanism ofaction ofinhibiting fatty acid synthesis by the inhibition ofthe enzyme acetylCoA carboxylase (ACCase). This herbicide controls some economically key weed species that impact crop production, specific weed species are, green foxtail 

### (Setaria viridis), yellow foxtail 

### (Setaria glauca), and giant foxtail 

### (Setariafaberi) as well as barnyardgrass 

### (Echinochloa crus-galli). Currently there are 2 weed biotypes that are re.sistant 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 1herbicides. Careful stewardship ofthis herbicide and other Group 1herbicides are needed in order to 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 ofIdaho, Montana and North Dakota. The types ofwheat produced in these states are durum wheat, hard red spring and winter wheat, and soft white spring and winter wheat. Seventy percent ofthe durum wheat was planted in North Dakota with a smaller amount in Montana (20%). 1 

### In 2010 and 2011, the average number ofacres ofdurum wheat harvested by farmers inthe states ofMontana and North Dakotatotaled 89% ofthe nation's durum wheat grain harvest. From 2006-2012, 90% ofthe totallbs a.i. ofclodinafop-propargyl was applied to 93% ofthe total acres treated (TAT) for the various types ofspring wheat; while 9% ofthe lbs a.i. had been applied to 7% 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. On average, for the years from 2006 to 2010, Montana and North Dakota farmers together accounted for 83% ofthe total.lbs a.i. ofClodinafop-propargyl used on 90% ofthe durum crop produced inthe nation. This niche market for this herbicide is very important in spite ofthe relatively low total national use of74,000 pounds active ingredient.

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

### 2The climate inthe two states, Montana andNorth Dakota, where clodinafop-propargyl herbicide is currently being used the most is characterized by very coldwinters with an average annual rainfall of 

### go inches3 and an average soil organic matter ofless than or equal to three percent 4• 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
, carryover to 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 in 2005, when use is averaged over all reported crops. Figure 1 presents the trend ofuse for clodinafop-propargyl in terms oftotal pounds.
Figure 1. Total Annual Agricultural Usage for Clodinafop-propargyl, 2000-2010 180,000

0 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 on winter 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.

Figure 2. Agricultural Usage :pata for Clodinafop-propargyl averaged over 2006-2010.

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 59717 http://www.montana.edu/cpalnews/wwwpb-archives/aglwhe
_fert.html 5 Vencill, W.K. ed. Herbicide Handbook, Eighth Edition
. 2002
. Weed Science Society ofAmerica. Lawrence, KS 66044. USA 

### 3100,000 ,------------------- --

..: 

## < "' "C c :s 0 D.

0 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 Four Herbicides Used for Weed Control in Wheat Production" was a review by the Biological 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 safener 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. BEAD concluded that all four ofthese herbicides would not be applied to the same wheat field in the same production season. BEAD did conclude that on very 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, and North Dakota is important for the control ofannual and perennial grasses. As discussed earlier in this document, because ofthe magnitude ofthe use in Montana and North Dakota where 89% ofthe harvested durum wheat produced in the US accounted for 83% ofthe clodinafop-propargyl use, it is clear thatthere is an important niche use for this herbicide.

4

### References Proprietary Data, 2000-2010 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 Oqtlook Board, World Agricultural Supply and Demand Estimates. Online: http://www
.ers.usda
.gov /data-products/wheat-data
.aspx.

5

### APPENDIX Clodinafop-propargyl 

### Usage by 

### Crop Reporting District 

### (2006- 2010) Another measure ofusage is the use intensity. In this analysis, the use intensity is expressed as the pounds a.i. applied per 1,000 acres ofland in farms. This differs from the application rate, which is e. xpressed as the pounds a.i. applied per treated acre. Figure 3 spatially represents the use intensity ofclodinafop-propargyl on wheat inthe Dakotas.

Clodinafop-proporgyl Use (2006-2010)
. by Crop Reporting District Average Pounds per 1,000 Acn:s ofFarmland

- <011

. 0
. 11 · 025 c::::J o .26-o
.so 0.5 1

- 2
.00

- 201

- 2
.50
This is a map ofagricultural P<lSticide 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 pounds (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 defined 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 

### 6used for growing crops, grazing livestock, or the potential of grazing livestock was included as land in farms. Land in reservations not reported by reservation, individual American Indians or non-Native**Ameri~ans** 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, USOA). Usage is based on private market surveys of pesticide 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 CRJ?. 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/anns/ resourceregions/resourceregions.htm#nass
. USDA, 2007. Census ofAgriculture. http://www.agcensus.usda.gov/Publications/2007/index.asp.



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