UNITED STATES ENVIRONMENT AL PROTECTIONAGENCY WASHINGTON D.C., 20460 

## JUN 11 2015

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION
MEMORANDUM SUBJECT:

FROM:

THRU:

TO: Fenoxaprop and Fenoxaprop-ethyl Qualitative & 128701) Bill Chism, Ph.D., Senior Biologist Biological Analysis Branch Michelle Ranville, Ph.D., Economistr**('(\~** 

### ry-:} Economic Analysis Branch 

## U**~** Biological and Economic Analysis Division (7503P) Arnet Jones, Chief 

# (I r'1

# ~ BiologicalAnalysis Branch

# ~~(J I• Timothy Kiely, Chief

# ~**~ \~**  J Economic Analysis Branch 1\". · Biological and Economic Analysis ivision (750 Miguel Zavala, Chemical ReviewManager Tracy Perry, TeamLeader Kelly Sherman, Acting Chief Risk Management and Implementation Branch III Pesticide Reevaluation Division (7505P)

BEAD ProductReview Panel date: May20, 2015

### SUMMARY Fenoxaprop and fenoxaprop-ethyl are undergoing registrationreview. As part ofthe risk managementphas

_ e, the Biological and Economic Analysis Division (BEAD) conducted a qualitative assessment ofthe benefits offenoxaprop and fenoxaprop-ethyl. Fenoxaprop-ethyl (PC Code 128701) is a post emergence herbicide usedto selectively control annual and perennial grass weeds with labeled use sites onfallow, rice and soybeans. Fenoxaprop (PC Code 129092) has labeled use sites on fallow, barley, cotton, right-of-way, ornamentals, turf, rice, and wheat. Datain this document cover both active ingredients, fenoxaprop and fenoxaprop-ethyl; the two active ingredients are referred to collectively as fenoxaprop. This qualitative assessment reviews four example crops to determine whetherfenoxaprop formulations are an effective tool for selective control ofgrass weeds inbarley, rice, soybeans, and wheat (spring and winter).


### BACKGROUND
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires EPA to register pesticides before they canbe distributed and used and to re-evaluate· the registrations at least once every 15 years. FIFRA requires the EPA to regulate the use ofa pesticide to the extent necessary to prevent unreasonable adverse effects onthe environment, including humanhealth, where 'unreasonable' is defined as taking into accountthe economic, social, and environmental costs and benefits ofthe use ofthe pesticide. The primary risk concern for fenoxaprop is to non-target terrestrial (monocot) plants, primarily from spray drift resulting from aerial applications. There have also been a series ofincidents reported for grain crops treated withfenoxaprop. (EPA, 2014). Fenoxaprop-ethyl (PC Code 128701) and fenoxaprop (PC Code 129092) are post emergence herbicides usedto selectively control annual and perennial grass weeds innumerous crops. Fenoxaprop inhibits acetyl CoA carboxylase enzyme (ACCase) (WSSA Group 1) and"interferes with meristematic tissue development. Grass herbicides like fenoxaprop canbe a tool inthe control ofherbicide resistant (e.g., glufosinate, glyphosate, acetolactate synthase) volunteer com in broadleafcrops such as soybeans but unless they are usedproperlythey can select for ACCase resistant weeds. ACCase herbicides have many herbicide resistant weeds with over 40 resistant weed species in the United States.
For agricultural uses, fenoxaprop is generally applied earlyto late post emergence to the crop and weeds using ground equipment with lowbooms. Onlytwo crops show significant aerial applications with 8% oftotal acres treated for barley (approximately 240 thousand acres) and 53% percent oftotal acres treated for rice (approximately 87 thousand acres). (Chism et. al., 2015) Dataon applicationtiming indicate that the rice aerial applications were made to accommodate the large number ofacres involved and not specifically because ofwet fields since they were applied pre-flood; only a small number ofacres were treated post-flood. Itappears that the barley aerial applications generally occurred late post so thatthe large fields could be treated in a short amount oftime whenthe weeds were most sensitive. (Chism et. al., 2015) Page2QUALITATIVE BENEFITS Between 2009 and 2013, fenoxaprop has been shownto be used primarily onbarley (20,000 lb. ai/year), rice (10,000 lb. ai/year), soybeans (20,000 lb. ai/year), and spring/winter wheat (200,000 lb. ai/year) (Chism et. al., 2015). Percent crop treated is approximately 10 percent for barley, 5 percent for rice, 2.5 percent for soybeans, and 10 percent for wheat. (Chism et al, 2015) This assessment reviews these four example crops (selected based onhighest proportion of usage) and concludes that fenoxaprop formulations are an effective tool for control ofdifficult to control weeds and prices are comparable or lowerthan alternatives

. . Barley and Wheat In barley and wheatproduction inNorth Dakota, fenoxaprop provides excellent selective post emergence control ofseveral difficult to control annual grass species such as wild oat, foxtail (green and yellow), and bamyardgrass (Zollinger, 2015). Inbarley and wheat in California, fenoxaprop is considered part ofan integratedpest management (IPM) program for the control of canarygrass, wild oat, and foxtail (green and yellow) (Univ. ofCal., 2009). Inbarley and wheat, fenoxaprop formulations are used as part ofan IPM programto control several difficult to control weeds and are less expensivethan several ofthe alternative herbicides. Rice In rice production inMississippi, fenoxaprop is recommended for control ofseveral difficult to control annual and perennial grass species such as bamyardgrass, sprangletop, broadleaf signalgrass,johnsongrass (seedling), and fall panicum (MSU, 2015). In California fenoxaprop is recommended for control ofsprangletop (California Rice Research Board, 2003). Inrice, fenoxaprop formulations control several difficult to control weeds and are priced comparably to the alternative herbicides. Soybeans In soybeans in Alabama, fenoxaprop is recommended for selective post emergence control of several difficultto control annual andperennial grass species such as fall panicum, foxtail spp., and shattercane (ACES, 2015). Grass herbicides like fenoxaprop-ethyl are an important tool in the control ofherbicide resistant volunteer comin broadleafcrops such as soybeans. In soybean fenoxaprop formulations control several difficult to control weeds including glyphosate-resistant comand are less expensive than several ofthe alternative herbicides.

Page 3CONCLUSION Fenoxaprop is used for selectivepost emergence control ofdifficult to control annual and perennial grass species in barley, rice, soybeans, and winter and spring wheat. As a post emergence treatmentthe grower can avoid making prophylactic preemergence applications. In these crops fenoxaprop is less expensive than some ofthe other available alternative herbicides. Fenoxaprop is generally applied earlyto late post emergence to the crop and weeds using ground equipment, with lowbooms. It is applied aerially to rice (53% ofacres treated) to accommodate a large number ofacres treated, and it is applied aerially to barley (8% ofacres treated) so that large fields canbe treated in a short amount oftime when the weeds were most sensitive.

REFERENCES ACES. 2015. Soybean, Insect, Disease, Nematode, and Weed Control Recommendations 2015. IPM-0413. Alabama Cooperative Extension System, Alabama A&M and Auburn Universities. Accessed online on April 24, 2015 at http://www.aces.edu/pubs/docs/I/IPM-0413/IPM-0413.pdf California Rice Research Board. 2003. Weed Control inRice. Accessed online onApril 24, 2015 at http://www.carrb.com/02rpt/Weeds.htm Chism, W., J. Alsadek, and M. Ranville. 2015. Fenoxaprop-ethyl Usage Information (PC# 128701 & 129092). Biological and Economic Analysis Division, Office ofPesticide Programs, EPA. EPA. 2014. Environmental Fate and Ecological Risk Assessment for the Registration Review of Fenoxaprop-p-ethyl. Environmental Fate and Effects Division, Office ofPesticide Programs, EPA. Mississippi State University (MSU). 2015. Weed Control Guidelines for Mississippi. Mississippi State University. Accessed online on April 24, 2015 at http://msucares.com/pubs/publications/p1532.pdf Proprietary data. 2004-2013. University ofCalifornia. 2009. Pest Management Guidelines, Small Grains. Accessed online onApril 24, 2015 at http://www.ipm.ucdavis.edu/PMG/r7307001l l.html Zollinger, R. editor. 2015. North DakotaWeed Control Guide. Hard Red Spring and Durum Wheat, Winter Wheat and Barley. Accessed online onApril 24, 2015 athttp://www.ag.ndsu.edu/weeds/weed-control-guides/nd-weed-control-guide-1/wcgfiles/3.1-Wheat.pdf

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