UNITED STATES ENVIRONMENTAL PROTECTION AGENC Y WASHING T ON, D.C

. 20460 

### MAY 2 3 

### 2014

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVEN T ION 

### MEMORANDUM SUBJECT: FROM :

THRU :

TO : BEAD Chemical Profile (BCP) for Registration Review: Triallate (078802) Bill Phillips , Ph.D
. , Agronomis t

# ~ Biological Analys i s Branch 

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### A/-'~ Jihad A l sadek, Ph.D. , Economist J v

## ~fA Science Information and Analysis Branch Stephen Smearman , Economi st**~.** .. 1 

## J Economic Analysis Branch**~~** Biological and Eco nomic Analysis Divi s ion (7503P) Arnet Jones, Chief 

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-**.II J~**  B iological Analys is

## Bran~y [/ Diann S im s, Chief Science Information and Analysis Branch 

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T imo thy Kiely, Chief 

# f.+ \JJ\_ Economic Analysis Branch 

### "'-! ) Biologica l and Economic Analysis Division (7503 ) Katherine StClair, Chemical Review Manager Risk Management and Implementation Branch 4 Pesticide Re

- evaluation Division (7508P)


### Peer Review Panel date: May 14,2014
SUMMARY Triallate was first registered as a pesticide in the U.S. in 1961 (US EPA, 200 I) and a Registration Eligibi lity Decision (RED) document was pub li shed in 2000.As a member of the Weed Science Society of America group eight herbicides , triallate has the mechanism of action of inhibiting the synthesis of fatty acids and lipids. Triallate is used to control persistent grass weeds such as wild oats 

### (Avenafatua) in barley and wheat. Weeds like wild oats are ofparticular importance since they reduce crop yields and can be harvested along with the crop and is considered a contaminate when brought to market. In wheat and barley, triallate can be used preplant incorporated thus providing control prior to emergence of the weed. By controlling wild oats prior to emergence, competition between the weed and crop is avoided and it keep s the seed from being harvested and contaminating the harvested crop grain. Because there is a 12 month restriction for planting any crop other than those currently regi stered for its use , and because triallate does not control emerged weed, there may be an advantage to u sing postemergence herbicides for controlling grass weeds. Because ofthe large decrease in usage during the time period from 1998 to 2012, BEAD has determined t hat the utility of this herbicide has les sened and thus may have been displaced by another herbicide or method of weed control. Based on private market usage data from 1998-2012, usage averaged approximately 874,000 pounds active ingredient (a.i.) applied annually on approximately 792,000 acres treated. The average a.i. rate over this time period was 1.10 pounds a.i. /acre
. T he use of triallate between the years 2008 and 2012 averaged less than 160,000 lbs. a.i. and the percent crop treated was less than 2.5 percent for all crops. There are no reported usage data for non-agricultural use sites. The relatively low percent crop treated on these crops indica te low benefits, or at the very least, a low reliance on triallate to control weeds in these crops. INTRODUCTION The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview of the pest management roles and quantitative usage information for triallate. The BCP includes summaries ofprevious BEAD products and available public and/or private use and usage data for triallate to describe the role of this chemical in pest management. Information provided in this BCP may be used by stakeholders (e.g., users and registrants), OPP risk assessors, OPP risk managers, and the general public during the Registration Review process of this pesticide. USE SITES Agricultural Use Sites Triallate's registered agricultural us e sites include: Bermudagrass (grown for seed or hay), dry beans and peas, green peas, lentil s, barley, spring wheat, triticale and su gar beets.

2FORMULATIONS AND APPLICATION METHODS Triallate is formulated as emulsifiable and granular. Depending on the crop, triallate may be applied before or after planting, either by ground or aerial equipment. Application is typically made either in the fall or in the spring, before targeted weed species germinate. HISTORY OF TRIALLATE and BEAD PRODUCTS Triallate is an herbicide registered for use in the U.S. since 1961 and a RED was published in 2000. A search of the BEAD database for previous BEAD products for trialla te indicates that there are no records of prior BEAD benefits assessments or emergency exemption requests for triallate in the last 10 years. Note that a lack of emergency exemption requests does not indicate the relative importance ofthe chemical. A Screening Level Usage Analysis (SLUA) was prepared by BEAD for this chemical in 2014 that provides percent crop treated for barley, dry beans/peas, green peas, sugar beet s and wheat. For triallate, the agricultural sites with the greatest number of pounds used were for wheat followed by barley. In terms of the percent crop treated, all crops are less than 2.5 percent treated. There has been a s ignificant decline in both the total pounds oftriallate used and the total area treated over the reported use period
. In addition, the relatively lo w percent crop treated for triall ate on the top crops indicate low benefits , or at the very least, a low reliance on triallate to control weeds in these crops . USAGE Agricultural Usage Based on private mar ket usage data from 1998 -20 12, usage averaged approximately 874,000 pounds active ingredient (a.i.) applied annually on approximately 792 , 000 acres treated. The average a.i. rate over this time period was 1. 1 0 pounds a.i. /acre. The use of triallate decreased by 92 percent since 1998. Figure 1 presents triallate usage in pounds a.i. over the 1998

- 2012 timeframe. Figure 2 presents total area treated in acres over the same timeframe (Proprietary Data, 1 998

-20 12).

3

### FIGURE 1. 

### Trialla te Usage in Pounds Active Ingredient ( 1998-2012) 3.500 , 000



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- 2012 (' l ("", -q- 1n**~** '-' 8 8 ,.... ,r-- 8**~** C5 c 8 0**~** 0 (' I ('I (' I ('I (' ) 

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FIGURE 2. T riallate Total Area Treated in Acres (1998-2012) 3 ,000 ,000**~** Q) 

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-2012 0 0 (' I**~I** ("", -q- '.0 ':£ r-- 

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4Table 1. Comparison of Crops with Highest Use of Triallate- Percent of Total Lbs. Applied (1998

- 2002 and 2008-2012) 1998-2002 2008-2012 Average Annual Usage = 2,000 , 000 lbs/y r Average annual = 156,000 lbs/yr Crop %Lbs Crop %Lbs Spring Wheat 54 Barley 35 Barley 32 Spring Wheat 32 Winter Wheat 8 Dry Beans/Peas 21 Dry Beans/Peas 3 Winter Wheat 11 Other 3 Other I Source: Propnetary Data, 1998 -2012. Table 2. Comparison of States with Highest Use of Triallate- Percent of Total Lbs. Applied (1998-2002 and 2008-2012) 1998 -2002 2008-2012 Average Annual Usage = 2,000,000 lbs/yr Average Annual Usage= 156 ,000 lbs /yr State %Lbs State %Lbs Montana 47 Washington 42 North Dakota 27 Montana 30 Idaho 12 Idaho 20 Washington 11 North Dakota 4 Other 3 Other 4 Source: Proprietary Data, 1998

- 2012 The major agricultural use oftriallate during the 1998

- 2002 and 2008-2012 time frames are spr ing wheat and barley , with use contracted in Montana, North Dakota, Idaho and Washington. Overall use has declined over 90 percent betwe en 1998

- 2002 and 2008

-2012 with similar decl ines in most states. The average annual a.i. rate for the top crops was the highe st for barley at 1
. 109 lbs. a.i./acre and the lowest for dry beans/peas at 0.963 lbs. a.i./acre as shown in Tab le 3. Application Rates 

### T bl 3 

### T
. II t U

a e 

# . raa a e se on T C op rops: A verage An IAI R nua 

# .. ate, 2008 2012 

## - Average Annual Average Annual Avg
. Annual A.l. Crop Pounds A.I. Rate (lbs Applied Total Acres Treated* a.i.lacres) Barley 54 , 533 49,177 1.109 Spring Wheat 50,567 49,441 1.023 Dry Bean/Peas 33,139 34,397 0.963 Winter Wheat 17,968 17,889 1
.000 *Total Acres Treated sums all acres treated for a crop, including those acres that receive multiple treatments . Source: Proprietary Data, 2008 -2012

5Geographic Distribut ion of Triall ate Use

Pounds Active Ingredient per 1.000 Crop Acres Grown CJNoOat a 0 < 0 ,3 2

. 0
. 32 · 0
.59

- 0
.60

- 5
. 50

- >5
. 50 Figure 3 . Annual average agricultural use intensity of TriaUate (2008- 2012). The map included herein is primarily for the use ofthe risk assessors in the Environmental Fate and Effects Di vision. The map provides a very broad geographical view of the average annual amount (in pounds) of the active ingredient applied per 1,000 acres of crop acres grown. These data are included in the maps because ri sk assessors are interested in the amount of a pesticide us ed across agricultural land. The calculated values presented in the map are not equivalent to an application rate (lb. a.i. /A). The data used to make these maps have several limitations
. Any interpretation of the maps should consider the underlying data and the associated limitations carefully. The numerator (annual average pounds app li ed) is based on private market surveys of pesticide use in agriculture averaged over the last five years (Proprietary Data , 2008

- 2012). These surveys cover about 60 crops and are targeted in states tha t produce the majority ofthe crop. Although the surveys capture most of the use of a particular active ingredient in agriculture, there are several limitations to these surveys .

6• States with minor production of a surveyed crop are not samp led • Not all types of pesticides are surveyed in every crop in every year • Many specialty crops with very small acreages are not included in the survey The result of these limitations is that states that s ho w no usage may actually have a small amount of the active ingredient being used. In some cases the displayed use intensity may be distorted because the surveyed crops and the reported pesticide usage may not accurately represent the actual pesticide usage on the crops produced in the state. The denominator ( 1,000 crop acres grown) was also obtained from the same private market survey database. The "Crop Acres Grown" variable represents the total acres grown in a given state of all of the surveyed crops. Thi s value is independent of pesticide usage and pesticide registration. It is important to note that the surveyed crops (about 60) are sampled from states that are major producers of each crop. Therefore, there are cases where the actual crop acreage in a state i s higher than that reported by crop acres grown in the survey becaus e either that state and/or crop was not included in the survey. The reader should pay particular attention to the figure legends and realize that a map prepared for a part icular chemical is not directly comparable to a map prepared for a different chemical as the legend bins will likely be different. Non

- Agricultural Usage There are no reported usage data for non-agricultural use sites.
CHEMICAL AND USE CHARACTERISTICS FOR TRIA LLATE Triallate is a preplant-incorporated herbici de that can be applied in the fall prior to the crop being planted or in the spring either incorporated preplant or after the crop has been planted. On average , this herbicide is applied only once per cropping season for barley, dry beans/peas and spring wheat. Triallate is used in several crops to provide preemergence control of grass weeds such as wild oats. As a member of the Weed Science Society of America group eigh t herb icides , triallate has the mechanism of action of inhibiting the synthesis of fatty acids and lipids. The mode of action ofthis herbicide is the inhibit ion of growth of the coleoptile (sheath covering the growing tip) ofthe new ly emergin g grass weeds (Senseman 

### et al. 2007).

ROLE OF TRIALLATE IN PEST MANAGEMENT 

### Triallate is used to control persistent grass weeds such as wild oats (Avenafatua). 

### Wild oats are ofparticular concern since this weed reduces crop grain production by competing with crops,
7such as barley and wheat, for resources. In addition to competing with crops, the grain from wil d oats i s harvested along with crop grain which reduces grain quality (Pokorny 

### 2007). The mixing of the weed seeds and the crop grain can result in growers paying a penalty because of the added cost to separate the w il d oats seeds from the grain
. The majority of herbicides that
. are used to control wild oats are postemergence applied
. Some of these postemergence herbicides provide some level of residual control. However, in wheat and barley crops triallate can be used preplant incorporated thus providing control prior to emergence ofthe weed (Warrick 

### eta!. No date provided). By contro lli ng wild oats prior to emergence, competition between the weed and crop is avoided and the continued control via the residual activity reduces the potential for harvested seed to contaminate the harvested crop grain. A drawback ofusing triallate is that there is a 12 month restriction for planting any crop other than those currently registered for its use. For this reason there may be an advantage to using the postemergence herbic ides for controlling wild oats and other grass weeds. In addition, because of the large decrease in usage during the time period from 1998 to 2012 , BEAD has determined that the utility of this herb icide has lessened and thus may have been displaced by another herbicide or method of weed control.
DATA NEEDS The Agency currently does not have important information on triallate. Obtaining information on crops that are registered but our proprietary database does not survey such as lentils and tri ticale and on non- agricultural use sites such as grasses may improve future assessments conducted by the Agency related to the use and importance of triall ate . Information on pounds a.i. applied, percent crop treated, application rates and where and when triallate is used
. REFERENCES BEAD, 2014. Triallate Screening Level Usage Analysis
. Biological and Economic Analysis Division, Office of Pesticide Programs , US Environmental Protection Agency. January 14,2014 Pokorny, M. 2007. Wild Oat 

### (Avenafatua). Accessed at: http: //ipm.montana.edu/cropweeds!Extension /weed%20species%20

- not%20every%20file%20is%20here-/Wild%20oat.htm Proprietary Data. 1998

-2012
. Senseman, S.A. (2007), Her b icide Hand Book Ninth Edition. Weed Sci. Soc. ofAm. 810 E. 10 1 h Street, Lawrence , KS 66044-8897. U .S.A.

8USDA, 2006

- 2010. NASS Crop Reporting Districts (shape file ofCRDs)
. Available at: http: //www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass . USDA, 2006-2010. NASS Crop Reporting Districts. Online: http: //www.nass.usda
. gov/Data and Statistics / County Data Files/Frequently Asked 

### 0 uestions /county list.txt USDA, 2007. Census of Agriculture. Online: http: //www.agcensus.usda.gov /Publications/2007 /index.asp
. USDA, 2007. Census of Agriculture
. (for Land in Farms data). Available at: http: //www.agcensus.usda.gov / Publications/2007/ index.asp
. http: / /www.epa.gov/oppOOOO 1/chem search/reg actions/reregistration/fs PC-078802 1-MarOl.pdf http: //www.epa . gov/oppOOOO I /chem search/reg actions/reregistration/red PC-078802 1-AugOO.pdf Warr ick, B. E
. and T. Baughman. (No date provided) W ild Oat Control in Texas
. Accessed a t : http: //sanangelo.tamu.edu/extension/agronomy / agronomy -publications /wild

- oat
- controlpublication/ 

### APPE ND I X A The map included herein primarily for the use ofthe risk assessors in the Environmental Fate and Effects Division. The map provides a very broad geographical view of the amount (in pounds) ofthe active ingredient app li ed per 1,000 acres of" land in farms "
. These data are included in the maps because risk assessors are interested in the amount of a pesticide used across farmland. Because of the definition of Land in Farms, as discussed below, the calculated values presented in the map are not equivalent to an application rate (lbs a.i. IA)
. The data used to make these maps have many limitations
. Any interpretation of the maps should consider the underlying data and the associated limitations carefully. The smallest areas shown on the maps within each state are Crop Reporting Districts (CRD). CRDs are defined by USDA and each consists of multiple counties that have similar soils, growing conditions , and farming practices. The CRDs within many states have roughly the same area . Because it is not feasible to conduct an agricultural survey that samples every county in the United States, the use of C RDs allow for a sample to be collect ed that represent a much larger area with relatively homogeneous agricultural characteristics. The numerator (annual average pounds applied) is based on private market surveys ofpesticide 

### use in agriculture averaged over the last five years (Proprietary Data, 2008

-2012). The se surv eys cover about 60 crops and are targeted in sta tes that produce the majority of the crop. Although


### 9the surveys capture most of the use of a particular active ingredient in agriculture, there are several limitations to these surveys.
• States with minor produc tion of a surveyed crop are not sampled Not all types of pesticides are s urv eye d in every crop in every year • Many specialty crops with very small acreages are not included in the survey The result ofthese limitations is that CRDs that show no usage may actually have a small amount of the active ingredient being used. The denominator (1,000 Acres ofland in farms) was selected from the Census of Agriculture (USDA, 2007) to represent agricultural acreage that i s actively managed and includes most ofthe areas treated with pesticides. The category "Land in Farms" is defined by the Census of Agriculture as being made up of four components: • Total cropland • Permanent pasture • Total woodland • Land in farmsteads, buildings , livestock facilities, ponds, roads , wasteland, etc. This category includes land in the various USDA conservation programs. It should be noted that the Census of Agriculture does not include grazing land rented (on a per-animal basis) from the Bureau of Land Management or Fore st Service, thus it is an undere stimate ofthe land being managed for agricultural purposes. The reader should pay particular attention to t he 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 of measurement do matter and may be different between maps.

10