UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 

### MAY 

## 19 2011

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM
SUBJECT: BEAD Chemical Profile for Registration Review: Benfluralin (084301)
FROM: Sunil Ratnayake, Botanist

# ~- 

# A'lVv1 Biological Analysis Branch \. 'V'<.J.-.. \ SepehrHaddad, Environmental Protection Specialist / 

# 1'-../ 

# 1/ I Science Information and Analysis Branch 

## '7 Andrew Lee, Economist 

# tJ..1. (!. Economic Analysis Branch 

# 1 Biological and Economic Analysis Division (7503P) THRU: Arnet Jones, Chief Biological Analysis Branc Diann Sims, Chief /'

### (2::1 --#'L-'7'..9-H'-n/l....-1. Science Information and AnalYGJiS ch Timothy Kiely, Chief ' Economic Analysis Branch Biological and Economic Analysis Division (7503P) TO: Katherine S1. Clair, Chemical Review Manager Risk Management and Implementation Branch 2 Pesticide Reevaluation Division (7508P)


### Product Review Panel date: May 11,2011 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 ofBenfluralin (084301), and eventually the general public. This documentbuilds 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 ofMay, 2011. Benfluralin belongs to dinitroraniline class ofherbicides and it is applied as apre-emergence treatmentto control grasses and small seeded broadleafweed species. Benfluralin is used in many , agricultural and non-agricultural sites (USEPA, 2004). Benfluralin needs to be soil incorporated to minimize the loss ofherbicide activity due to photodecomposition and volatility (Dow Chemical Co., 2010). Benfluralin inhibits the cell division and act as a mitotic poison. Therefore, growing points such as roots and shoots are most affected. It is absorbed by roots and shoots ofemerging weed seedlings (Peterson et al., 2010). Benfluralin can be applied alone or tank mixed with other compatible herbicides to increase the weed control spectrum (Dow Chemical Co., 2010). USE SITES Agricultural Use Sites Benfluralin is used to control grasses and small seeded broadleafweeds in lettuce, alfalfa, peanut, clover, birdsfoottrefoil, nonbearing fruit and nut trees, nonbearing berries, and nonbearing vineyards. Non-Agricultural Use Sites Benfluralin is used to control weeds in ornamentals, rights ofway including industrial sites, utility substations, highway guardrails, sign posts, and irrigation systems.
COMMON FORMULATIONS AND APPLICATION METHODS It is formulated as emulsifiable concentrate, granules, soluble concentrate/liquid, water dispersible granules and ready- to- use -solutions. Benfluralin can be applied using tractor mounted sprayers or hand sprayers. USAGE Agricultural Usage Based on private market usage data from 1998-2010, usage averaged approximately 100,000 pounds active ingredient (a.i.) for 100,000 acres treated (Proprietary Data, 1998-2010). Figure 1 presents benfluralin usage over the 1998-2010 timeframe for alfalfa, lettuce and peanuts. Minor benfluralin usage has been reported ontobacco, while usage has also been reported on three sites for whichbenfluralin is not registered; onions, broccoli, and pasture/range. The use onpeanuts was voluntarily cancelled in 2008.

2FIGURE 

### 1. 

### Benfluralin Usage (1998-2010) 250,000 

# I 

# I

o • Peanuts

• lettuce

• Alfalfa

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Years Source: Proprietary Data, 1998-2010 Between 2008-2010, the states with the most agricultural usage in terms ofpounds a.i. applied were Arizona (60%), California (19%) and Alabama (19%). Other states (2%) where use has been reported between 2008-2010 are Georgia and Tennessee (Figure 2).
USE TRENDS As shown in Figure 1, between 1998 and 2010, benfluralin use reached apeak in 1999 and the lowest use was reported in 2009. An increase in use occurred during 2008 but use was cancelled in September ofthat year, and therefore no usage is shown for peanuts in 2009 and 201D, the most recent years for which we have data. Use on alfalfa was the highest in 1999 and steadily decreased until 2004. Usage on alfalfa increased from 2006 through 2008 and there was no use reported in 2009. The use ofbenfluralin on lettuce has remained fairly constant from 1998 through 2008, with the least use on lettuce reported in 2009. Figure 2 presents the states with the highestpounds a.i. used from 1998-2000, as compared to the states with the highestpounds a.i. used from 2008-2010. As shown in Figure 2, the proportion of use in California has decreased by approximately 50% withinthe last decade, while use in Alabama has increased during the same periodto approximately 20% oftotal pounds a.i. applied. A review ofproprietary data indicates that this is due to a decrease in use on alfalfa in California and the increase in use on peanuts grown in Alabama in 2008 before the use on peanuts was voluntarily cancelled. The last pie chart in Figure 2 shows the states with the highest use in 2009-2010 after the use on peanuts was cancelled.

3

### FIGURE 2. Comparison ofStates with Highest Use Between 1998-2000 and 2008-2010 Timeframes & 

### States with Hi hest Use in 2009-2010 After Cancellation ofPeanut Use States with Highest Use - Percentof Total Lbs. Applied 1998-2000

States with Highest Use - Percent ofTotal Lbs. Applied 2008·2010

OTHER

2%

States With Highest Use - Percent of Total Lbs. Applied 2009-2010 (after cancellation of use on peanuts in 2008)

Source: Proprietary Data, 1998-2010

4Non-Agricultural Usage In terms ofnon-agricultural usage, data are available for usage by consumers for lawn use and for lawn care operators (LCO's) and for uses such as golfcourses, landscape, nursery/greenhouse, and turffarms. Generally, over the reported years (1999 through 2006), the majority ofuse was by consumers, LCO's and golfcourses. Consumers used 1.8 millionpounds a.i. in 2000; 800,000 pounds a.i. in 2003, and 800,000 pounds a.i. in 2005. LCO's used approximately 171,000 pounds a.i. in 1999. Use decreased to approximately 85,000 pounds a.i. in 2002; 99,000 pounds a.i. in 2004; and 35,000 pounds a.i. in 2006. Benfluralinuse on golfcourses declined from 1999 through 2006, with approximately 45,000 pounds a.i. used in 1999; 16,000 pounds a.i. in 2002; 8500 pounds a.i. in 2004; and less than 300 pounds a.i. in 2006. Finally, for Nursery/Greenhouses, the amount reported used has fluctuated from 21,000 pounds a.i. in 1999 to approximately 200 pounds a.i. in 2002; less than 100 pounds a.i. in 2004; and increased to approximately 2500 pounds a.i. in 2006 (Kline and Co., Inc. 1999-2006).


### BIOLOGICAL ASPECTS RELEVANT TO BENFLURALIN Inhibition ofcell division is the mode ofaction ofthis herbicide. Therefore, it affects the growing areas ofthe weeds such as roots and shoots (Peterson et al., 2010). Dinitroraniline herbicides have been used more than 25 years and several weed species have developed resistance to the mode of action ofthis class ofherbicides (Heap, 1997). Biotypes ofpalmer amaranth (Amaranthus palmeri), wild oat (Avenafatua), goosegrass (Eleucine indica), annual bluegrass (Poa annua), green foxtail (Setaria viridis),andjohnsongrass (Sorghum hale pense) have developed resistance to dinitroraniline class ofherbicides (International Survey ofHerbicide Resistant Weeds, 2011). Goosegrass (Eleucine indica) is the most widespread resistant weed specie for the dinitroraniline group ofherbicides. Infestations ofdinitroraniline resistant goose grass were reported in cotton fields ofNorth and South Carolina, Alabama, Georgia, and Tennessee (Heap, 1999).


### HISTORY OF BEAD ASSESSMENTS FOR BENFLURALIN The only BEAD analysis regarding benfluralin is the alternatives assessment (Phillips, Zinn, and Faulkner, 2004) in support ofRe-registration Eligibility Decision (RED). According to this assessment, alternatives used for benfluralin on turfuse were trifluralin, dithiopyr, prodiamine, oxadiazone, oryzalin, and alternatives used on alfalfawere metribuzin, norflurazone, paraquat, pendimethalin, terbacil, and trifluralin. Also, alternatives used on lettuce were bensulide, propyzamide, benefin, and trifluralin. Althoughthe use on peanuts was cancelled in 2008 no BEAD analysis was conducted related to this cancellation.

5DATA NEEDS RELEVANT TO BEAD'S FUTURE WORK ON BENFLURALIN BEAD specific Registration Review issues, as relevant, including BEAD data gaps neededfor future assessments and BEAD work plan. None at this time. REFERENCES EPA R.E.D. Facts. Benfluralin. 2004. United States Environmental ProtectionAgency. http://www.epa.gov/oppsrrdllREDs/factsheetslbenfluralin fs.pdf Proprietary Data, 1998-2010. Heap, I. M. 1999. Occurrence ofHerbicide Resistant Weeds, Worldwide. http://www.weedscience.comlpaper/resist97.htm International Survey ofHerbicide Resistant Weeds. 2011. http://www.weedscience.org/In.asp Peterson, D. E., C. R. Thompson, D. E. Shoup, and B. L. Olson. 2010. Herbicide Mode of Action. Publication offKansas State University Agricultural Experiment Station and Cooperative Extension Service. http://www.ksre.ksu.edullibrary/crpsI2/c715.pdf Phillips, W II, N. Zinn, and J. Faulkner. 2004. Potential benfluralin alternatives. Memorandum submittedto Special Review Re-registration Division. July 15,2004. Product Safety Assessment. Benfluralin. 2010. Publication ofDow Chemical Company. http://www.dow.comlproductsafety/pdfs/233-00785.pdf

6