UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D
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## JUL Ot5 l012

MEMORANDUM OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: FROM: BEAD Chemical Profile for Registration Review: Foramsulfuron (122020) Sunil Ratnayake, Biologist 

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. Biological Analysis Branch 

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THRU: Jihad Alsadek, Economist

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### yf-~ Science Information and Analysis Branch Stephen Smearman, Economist 0 

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### . . Biological and Economic Analysis Division (7503P) AmetJones, Chief /]

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# lj Diann Sims, Chief Science Information and Analysis Branch Timothy Kiely, Chief

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# J. Biological and Economic Analysis Division 3P) TO: Jose Gayoso, Chemical Review Manager Risk Management and Implementation Branch 2 Pesticide Re-evaluation Division (7508P) Product Review Panel date: May 9, 2012 INTRODUCTION The purpose ofthis document is to convey usage information and a broad overview ofthe pest managementroles ofpesticides that are beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status offoramsulfuron, and eventuallythe general public. This document builds upon the data already provided inthe "Usage and Label Use DataPackages" that are also provided to Registration 1Reviewteams by BEAD. The document is based on information and data available to BEAD as ofMay 2, 2012. Foramsulfuron was initially registered in 2002 (EPA, 2002). Foramsulfuron belongs to the sulfonylurea herbicide family and it inhibits the activity ofacetolactate synthase (ALS) enzyme. It is a selective herbicide applied as a post-emergence treatment to control annual and perennial grass and broadleafweeds mainly in field com, sweet com, and non-agricultural sites described below. Foramsulfuron is absorbed by leaves and roots ofsusceptible plants andprovides very effective weed control at very low rates. COMMON FORMULATIONS AND APPLICATION METHODS Foramsulfuron is formulated as an emulsifiable concentrate. Ground applications with tractor mounted ground sprayers and aerial applications are recommended. USE SITES 

### Agricultural Uses Foramsulfuron is registered for use on com and sweet com. 

### Non-Agricultural Uses Foramsulfuron is registered for use on ornamental turf, domestic dwellings (outdoor), camp sites, schools (outdoor), and roadsides. USAGE Agricultural From 2002-2010, the annual total agricultural usage offoramsulfuron averaged approximately 17,000 pounds ofactive ingredient (a.i.) for 632,000 treated acres with an overall application rate of0.03 lbs. a.i. per acre. Less than one percent ofthe com crop is treated annually. During this timeframe, the crop with the most use in terms oftotal pounds ofactive ingredient applied and total acres treated is com (nearly 100%). Less than 0.1 percent is used on sweet com. On average, the states with the most agricultural usage in terms ofpounds a.i. applied and total acres treated are Nebraska (15%), Iowa (13%), Illinois (12%), and Indiana (11%).
USE TRENDS Figure 1 shows the trend in terms oftotalpounds offoramsulfuronused on com. There was no reported use in 2000 and 2001because 2002 was the initial year ofregistration; reported usage from 2002 through 2010 indicates a continuous decline in use. During the last three years, 2008- 2010, the application rate was still 0.03 lbs. a.i. per acre. 2

### Figure 1. Agricultural Usage Data ofForamsulfuron on Corn, 2002-2010

PoundsA.I.

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

### Foramsulfuron Agricultural Usage by Crop Reporting District Another measure ofusage is the use intensity. In this 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 2 spatially represents foramsulfuron use intensity on com. The highest use intensity was observed in Idaho, Nebraska, and Indiana as indicated bythe red color (Fig. 2). The data indicate that reported use in a given Crop Reporting District (CRD) is driven by the reported number ofpounds applied per acre oflandin farms extrapolated over the number ofgrowers in a particular CRD. So the use of foramsulfuron by a single user in an CRD that has a high number ofprojected users but a small number oftotal acres grown for a crop that might be treated with foramsulfuron may appear on the map as ifthere is very intense use in a CRD when in fact the use may be for only a very small number ofacres.

3Figure 2. Foramsulfuron Usage by Crop Reporting District (2006- 2010)

Average Pounds Per 1,000 Acres of Fannland

. 0.00-002 0.03-0
.05 c:::::J o.OS-0
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This is a map of agricultural pesticide usage at the Crop Reporting District (CRD) level. CRDs are boundaries created by USDA NASS which are aggregates of counties (USDA, 2010). Pesticide usage is displayed as average pounds (for the years 2006-2010) per 1,000 acres offarmland in a CRD to normalize for the variation in farmland between CRDs. Farmland acreage was obtained from USDA (2007). 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% of acreage for the individual crops; therefore, use may be occurring in regions outside the scope of the survey. CRDs showing no usage of pesticides 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. Non-Agricultural The main non-agricultural use offoramsulfuron is on golfcourses. The reported amount of forainsulfuron used on golfcourses approximately doubled from 500 lbs. a.i. in 2004 to 1,000 lbs. a.i. in 2006. Less than 500 lbs. a.i. was reportedly used for institutional turf, landscape, and lawn care operators (LCOs) from 2004 to 2006. BIOLOGICAL ASPECTS RELEVANT TO FORAMSULFURON Foramsulfuron is a sulfonylurea herbicide andthe mode ofaction ofthis class ofherbicide is inhibition ofacetolactate synthase (ALS) enzyme. Many weed species resistant to ALS inhibitors 4have beenreported in the United States. Presence ofannual bluegrass (Poa annua) biotypes specifically, with resistance to bispyribac-Na, foramsulfuron, imazaquin, and trifloxysulfuronsodiumhas been reported inthe State ofAlabama (Heap et al. 2012) The control ofweed species resistant to foramsulfuron canbe achieved by tank mixing a compatible registered herbicide with a different mode ofactionto foramsulfuron. Since the introduction ofRoundup ready comin 1988, the acreage ofRoundup ready comhas increased significantly. Therefore, the observed reduction offoramsulfuronusage on comfrom 2002 to 2010 may be due to the increase ofglyphosate usage in Roundup ready comproduction in the United States. HISTORY OF BEAD ASSESSMENTS FORFORAMSULFURON A search ofBEAD's document database did notreveal any previous BEAD assessments. DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON FORAMSULFURON Obtaining additional information ontypical foramsulfuron use inthe non-agricultural sector would improve future BEAD assessments onforamsulfuron and may be necessary as a part of the registration review ofthis pesticide. Requested data should include, but not be limited to application timing, application rate, application method, and application frequency. CONCLUSION The importance offoramsulfuron applied as a post-emergence treatment to control annual and perennial grass and broadleafweeds mainly in com and non-agricultural sites has been in decline. While foramsulfuron provides an effective weed control at very lowrates in corn, it appears to be losing market share, possibly to glyphosate products. REFERENCES Heap, I, H. Glick, L Glasglow, and W. Vencill. 2011. Herbicide Resistant Weeds by Country and Site ofAction. 2011. http://www.weedscience.org/summary /countrysummary.asp. Kline and Company, Inc., 2004-2006. Proprietary Data, 2002-2010. USEPA. 2002. Pesticide Fact Sheet. Foramsulfuron. http://www.epa.govIopprdOO 1 /factsheets/foramsulfuron.pdf
. 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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