UNITED STATES-ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C

. 20460 

### MAR 1 4 2016

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION MEMORANDUM SUBJECT:
FROM:

THRU:

TO: BEAD Chemical Profile for Registration Review: Ethofumesate: (PC Code: 110601) Sunil Ratnayake, Ph.D., Biologist

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

### v**~** ?JI"· Science Information and Analysis Branch Stephen Smearman, Economist 

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### ~ Biological and Economic Analysis Division (7503P) Colwell Cook, Ph.D., Acting Chief 

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# 1 Economic Analysis Branch Biological and Economic Analysis Division (7503P) Jordan Page, Chemical ReviewManager Risk Management and Implementation BranchV Pesticide Re-evaluation Division (7508P)
Peer Review Panel date: September 9, 2015

### SUMMARY Ethofumesate is a selective herbicide that was registered in the United States in 1977 (USEPA, 2005). It canbe applied as pre-plant, pre-emergence, and post-emergence treatments to control many economically important annual grasses and broadleafweed species. Itis used primarily on sugarbeets and onions. According to the WSSA (Weed Science Society ofAmerica) classification ofherbicides, ethofumesate belongs to the family ofbenzofuranherbicides (Group 16).
. Based onprivate market usage data from 2009-2013, usage averaged approximately 35,000 pounds active ingredient (a.i.) applied annually on 104,000 acres. The average applicationrate a.i. (active ingredient) over this time period is 0
.34 pounds a.i. /acre. From 2009 to 2013 the highest usage ofethofumesate was ononion and sugar beets. Minnesota, Oregon and California are the states withthe most usage. There are isolated reported usage data for table grapes and apricots, but no reported usage data for carrots. There are no reported usage data for nonagricultural use sites
. 

### INTRODUCTION The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an overview ofthe pest management roles and quantitative usage information for ethofumesate. The BCP includes summaries ofprevious BEAD products and available public and/or private use and usage data for ethofumesate to describe its role inpest management. Information provided inthis BCP may be used by stakeholders (e.g., users and registrants), OPP risk and benefit assessors, OPP risk managers, and the general public during the Registration Review of this herbicide. 

### USE SITES Agricultural Use Sites Registered agricultural use sites include: carrots, garlic, onion, shallot and beets (sugar beets, garden beets, and table beets). 

### Non-Agricultural Use Sites Non-agricultural use sites which are registered for ethofumesate application include: grasses grown for seed, ornamental lawns, turf, and ornamental sod farms. 

### FORMULATIONS AND APPLICATION METHODS Ethofumesate is formulated as a flowable liquid concentrate, emulsifiable concentrate, and soluble concentrate/liquid. It may be applied pre-plant, pre-emergence orpost-emergence. Application methods include banding, broadcast, soil-incorporation, and impregnated dry bulk fertilizer.

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### HISTORY OF ETHOFUMESATE and BEAD PRODUCTS A search ofthe BEAD database for previous assessments for ethofumesate indicates that there are no records ofprior benefits assessments or Section 18 Emergency Exemption Requests in the last 10 years. Recent Section 18 Emergency Exemption Requests might suggest that a chemical is important for the uses granted inthe request; however, a lack ofSection 18 Emergency Exemption Requests is not an indication ofthe relative importance ofthe chemical. 

### USAGE Ethofumesate is an herbicide that was registered for use inthe U.S. in 1977
. A Registration Eligibility Decision (RED) was published in 2005 and revised in 2007. Figure 1 & 2 presenttotal pounds a.i
. applied and total areatreated in acres overthe 1998-2013 time period (Market Research Data, 1998-2013)
. The use ofethofumesate, in terms oftotal pounds applied and total area treated in acres increased from 1998 through 2007, then decreased significantly from 2008 and 2009 before stabilizing in 2010-2013, as shown in Figures 1 

### & 2. 

### Figure 1. 

### Ethofumesate Usage in TotalPounds Active IngredientA plied (1998-2013)



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# .... . 1,200,000

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Source: Market Research Data, 1998-2013

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earsFi ure 2. EthofumesateTotal Area Treated in Acres 1998-2013) 2,500,000

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# s s .-4 .-4 N N N N N N N N N , , N , , N N Years Source: Market Research Data, 1998-2013 There were no reported usage data on onions during the 1998-2005 time frame. The reported use ofethofumesate during this period was totally on sugar beets. The use on sugar beets peaked in 2004, and decreased thereafter until 2009. The wide adoption ofglyphosate-resistant sugarbeets began in about 2009 which coincides with the steep decline in ethofumesate usage. (Figure 3). The major use ofethofumesate is on sugar beets and onions. The use on onions remained almost constant and has slightly increased since 2009 (Figure 3). The agricultural use sites interms of the number ofaverage annual pounds used were sugar beets (300,000 lbs. a.i) followed by onions (10,000 lbs. a.i.) for 2004-2013 time period. The crops with the greatestpercent crop treated include sugar beets, with an average of30 percent crop treated annually and onions with an average of20 percent crop treated annually. The annual percent crop treated for sugar beets and onions indicate that growers still find benefits for use onthese crops, or atthe very least, a reliance on ethofumesate to control pests on these crops.

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### Figure 3. Ethofumesate Usage in Pounds Active IngredientApplied on Onions and Sugar Beets, 2000

- 2013.

1.200.000

0 2<X>O 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 201 1 2012 2013

----- C>nions ---..- susar b eet.s '-----------------------------------------------
- Source: Market Research Data, 2000-2013 The use ofethofumesate is about 60% sugarbeets and 40% onions during the 2009-2013 time span, as shown in Table 1. 

### Table 1. Comparison ofCropswith Highest Use ofEthofumesate, PercentPounds AI Applied (2000-2004 and 2009-2013) 2000-2004 2009-2013 Average Annual Usage= 489,000 lbs/yr Average Annual Usage= 35,000 lbs/yr 

### Crop %Lbs Crop %Lbs Onions 57 Sugar Beets 100 Sugar Beets 42 Source: MarketResearch Data, 2000 -2013.

Page 5Inthe 2000-2004 time frame, the states with the highest use ofethofumesate interms ofpounds applied were North Dakota and Minnesota, the largest producers ofsugar beets. This changed in
· the 2009 to 2013 time period when use declined in North Dakota and Idaho and increased in

Minnesota, Oregon and California. Table

### 2. Comparison ofStates with HighestUse ofEthofumesate, in Terms ofthe Percent ofPounds Al Applied (2000-2004 and 2009-2013) 2000-2004 2009-2013 Average Annual Usage= 489,000 lbs/yr Average Annual Usage= 35,000 lbs/yr State %Lbs State %Lbs North Dakota 30 Minnesota 31

Minnesota· 27 Oregon 23 Idaho 13 California 18 Montana 8 Idaho 8 Wyoming · 7 North Dakota 8 Nebraska 5 Texas 4 Michigan 4 Washington 4 Source: MarketResearch Data, 2000 -2013 The average application rate (a.i.) for the top crops was the highest for onions at 0.44 lbs a.i./acre and the lowest for sugar beets at 0
.25 lbs. a.i./acre as shown in Table 3. Table 3. Ethofumesate Use on Top Crops (2009-2013) Average Annual Average Annual Crop Pounds AI Total Acres Aoolied Treated* Onions 20,000 45,000 Sugar Beets 15,000 59,000 *Total Acres Treated sums all acres treated for a crop. Source: Market Research Data, 2009 -2013
Geographic Distribution ofEthofumesate Use Average Annual A.I. LabelA.I. Rate (lbs. a.i. /acre) Max. App. Ran2e Rate 0.44 0.48-1.00 0.25 1.45-3.78

As the following map (figure 4) shows most use ofethofumesate is in Oregon and Minnesota. The map included herein is for general use inthe registration review process. The map provides a very broad geographical view ofthe total acres treated (TAT) over 5 years ofa pesticide on all agricultural crops. The map units are total acres treated, which accounts for all agricultural acreage treated withthis chemical and includes multiple treatments to the same area.

Page 61btalAcres lteated 

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- S>1-4,000

- 4,001-11,600

- 11,801-21,000 • •21,001


### Figure 4. TotalAcres Treated ofEthofumesate. (Source: Market Research Data, 2009-2013) The dataused to make these maps have many limitations. Any interpretation ofthe maps should considerthe underlying data and the associated limitations carefully. For example, there may be significant differences in the crop acres grown between states and there may be variation in the percent ofeach ofthe various crops treated by the pesticide. TAT is based onprivate market surveys ofpesticide use in agriculture averaged overthe last five years (Market Research Data, 2009-2013). These surveys cover about 60 crops and are targeted in states thatproduce the majority ofthe crop. Although the surveys capture most ofthe use ofa particular active ingredient in agriculture, there are several limitations to these surveys. • States with minorproduction ofa surveyed crop are not sampled • Not all types ofpesticides are surveyed in every crop in every year • Many specialty crops with very small acreages are not included inthe survey The result ofthese limitations is that states thatshow no acres treated may actually have a small ' amount ofthe active ingredient being used. In some cases, the displayed TAT maybe distorted because the surveyed crops and the reported pesticide usage (or TAT) does not accurately represent the actual pesticide usage on the crops produced inthe state. Page 7The 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 as the total acre treatment. intervals used inthe legend will likely be different. CHEMICAL AND USE CHARACTERISTICS FOR ETHOFUMESATE Ethofumesate is a selective and systemic herbicide that belongs to the benzofuran family (Group 16) ofherbicides (WSSA, Undated). The mechanism ofaction ofthis herbicide is not well understood, although it appears to inhibit lipid synthesis (Herbicide Handbook, 2014). Ethofumesate is readily absorbed by roots and shoots ofweed species. When ethofumesate is applied as a post-emergence treatment it is poorly absorbed by maturing leaves with a welldeveloped cuticle (Herbicide Handbook, 2014). ROLE OF ETHOFUMESATE IN PEST MANAGEMENT Ethofumesate is registered for the control ofmajor grass and broadleafweed species in sugar beets, garden beets, table beets, onions, garlic, shallots, and carrots. Itis also applied for selective control ofweeds in certain grass seed crops and commercial sod production in California, Idaho, Nevada, Oregon and Washington. Ethofumesate has a broad application window and can be applied as pre-plant, pre-emergence and post-emergence treatments. This herbicide controls broadleafweed species such as black nightshade (Solanum nigrum), common chickweed, (Stellaria media), common lambsquarters (Chenopodium album), Kochia (Kochia scoparia), redroot pigweed (Amaranthus retroflexus), Russian thistle (Sa/so/a Kali Var. tenuifolia) and wild buckwheat (Polygonum convolvulus). The major grass weed species controlled by ethofumesate are bamyardgrass (Echinoch/oa crus-galli), green foxtail (Setaria viridis), large crabgrass (Digitaria sanguinalis), and yellow foxtail (Setaria glauca) (Herbicide Handbook, 2014, Market Research Data). Based on Market Research Data for the period from 2011 to 2013, the top five pests in terms oftotal acres treated that ethofumesate is used to control are redroot pigweed, kochia, lambsquarters, chickweed and wormwood. According to Market Research data, the highest usage ofethofumesate was observed in 2004 on sugar beets (Figure 3). Shifting ofuse ofethofumesate to glyphosate to control weeds in sugar beetproduction maybe the major factor contributed to the observed low usage ofethofumesate on sugarbeets during the period from 2009 to 2013 (Figure 3). About 95 percent ofU.S. sugar beetproduction in 2013 was glyphosate-resistant varieties (GMO Compass, 2013). Ethofumesate may be tank mixed with compatible herbicides with different modes ofaction which may help manage weed resistance to ethofumesate. There are no reports ofany weed species with resistance to the mechanism ofaction ofethofumesate inthe United States (Heap, 2015).

Page 8DATANEEDS The Agency currently does not have important information on ethofumesate, such as pounds a.i
. applied and percent crop treated on some ofthe registered crops, such as carrots, garlic, and garden and table beets. In addition, obtaining similar information onnon-agricultural use sites such as grasses for seed, ornamental lawns and turf , and ornamental sod farms may improve future assessments.conductedbythe Agency.
REFERENCES BEAD, 2015. Ethofumesate Screening Level Usage Analysis (SLUA). Biological and Economic Analysis Division, Office ofPesticide Programs, US Environmental Protection Agency
. July 20, 2015. Ethofumesate 4SC Product Label. 2014. Willowood LLC
. 1600 NW Garden Valley Blvd. Suite # 120, Roseburg, OR 97471. Online Publication. Available at: http://www.willowoodusa.com/wp-content/uploads/2012/01/Ethofumesate-4SC-SpecLabel.pdf
. Accessed onJune 26, 2015. GMO Compass
. 2013
. USA: Cultivation ofGMplants. Online Publication. Available at:http://www.gmocompass.org/eng/agri
_biotechnology/gmo _planting/506.usa_ cultivation _gm _plants _2013

.html. Accessed onAug. 18, 2015. Heap, I. 2015. The International Survey ofHerbicide Resistant Weeds. Online Publication. Available at:http://www.weedscience.org/summary/ResistbyActive.aspx
. Accessed on June 25, 2015
. Herbicide Handbook. 2014. 10th edition. Weed Science Society ofAmerica
. Ethofumesate
. Pp. 184-185. 810 E. 10th Street, Lawrence, KS 66044-8897. Market Research Data (MRD). Various years. Datacollected and sold by a private market research firm. Datacollected onpesticide use for about 60 crops by annual surveys ofagricultural users inthe continental United States. Survey methodology provides statistically valid results, typically at the state level. · USDA- NASS, 2010. Available at: http://www.nass.usda.gov/Statistics by Subject/index.php?sector=CROPS
. Accessed on July 20, 2015. USEPA. 2005. Registration Eligibility Decision (RED) for Ethofumesate. Available at: http://www
.epa.gov/pesticides/reregistration/REDs/ethofumesate red.pdf
. Accessed on June 23, 2015.

Page 9WSSA, (Weed Science Society ofAmerica). (Undated). Summary ofHerbicide Mechanism of Action. Online Publication. Available at: http://wssa.net/wp-content/uploads/WSSAMechanism-of-Action.pdf. Accessed on August 18, 2015.

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