UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

NOV 0 4 2014 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

TO: 

BEAD Chemical Profile (BCP) for Registration Review: Oxyfluorfen (111601) 

Sunil Ratnayake, Biologist ~ _ l _ 0 --" 

Biological Analysis Branch ~ ··-.......yy \ v'\(('Yv<.ZJ--- ~ 

Rafael 

Science 

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Information 

Prieto, Environmental 

and Analysis 

Protection 

Branch 

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Stephen Smearrnan, Economist 

Economic 

Biological 

Analysis 

and Economic 

Branch 

Analysis 

~~ Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Branch 

Diann 

Science 

Sims, 

Information 

Chief ~ and Analysis Branch 

Economic 

Timothy Kiely, 

Analysis 

Chief 

Branch ~ ~ ~ Biological and Economic Anal is Division (7 ) 

Benjamin Askin, Chemical Review Manager 

Risk Management and Implementation Branch 1 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: October 15,2014 

Page 1 
SUMMARY 

Oxyfluorfen was first registered in the United States in 1979. Oxyfluorfen is a member of the 

diphenyl-ether family of herbicides. It is applied pre and post-emergence to control broadleaf 

and grassy weeds on a wider variety of use sites such as tree, fruit, nut, vine, and field crops and 

non-agricultural sites. 

Based on the available proprietary data, between the years of 2008 to 2012, in terms of the 

number of oxyfluorfen pounds applied to all crops the majority of the herbicide was applied to 

almonds (36%), grapes (20%) and walnuts (11 %). In terms of the percent crop treated for the 

top three sites that used oxyfluorfen, use of oxyfluorfen was on average applied to 65% of the 

almond acreage, 35% of the grape acreage and 55% of the walnut acreage (Table 1). In addition, 

according to the most recent Screening-level Usage Analysis for oxyfluorfen, other crops with 

high average percent crop treated include onions (75%), garlic (70%), and pistachios (50%). 

While the annual average number of pounds applied for these crops is lower than for top users 

such as almonds and grapes, the percent crop treated implies that oxyfluorfen is an important tool 

for growers of these crops in controlling weeds. In terms of the sites that use oxyfluorfen, usage 

of oxyfluorfen has not changed considerably during the period from 1998 to 2012 (Table 1 ). In 

terms ofthe states with the highest usage, California dominated with 93% of the total pounds 

applied nationally for the time period from 2008-2012 (Table 2). 

INTRODUCTION 

The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an 

overview of the pest management roles and quantitative usage information for oxyfluorfen. The 

BCP includes summaries of previous BEAD products and available public and/or private use and 

usage data for oxyfluorfen to describe the role of this chemical in pest management. Additional 

information on use is available in the oxyfluorfen Label Data Report. Information provided in 

this BEAD Chemical Profile (BCP) may be used by stakeholders (e.g., users and registrants), 

OPP risk assessors, and OPP risk managers, and the general public during the Registration 

Review process of this pesticide. 

USE SITES· 

The registered agricultural uses of oxyfluorfen include a wide range of fruits, including pome 

fruit, stone fruit, tropical fruit, subtropical fruit, nut trees, vegetables and field crops, agricultural 

fallow land and conservation reserve, Christmas tree plantations, shelterbelt, deciduous trees, 

forest trees (softwoods, conifers), and grasses grown for seed. 

Oxyfluorfen is also registered for use on the following non-agricultural use sites: 

household/domestic dwellings, outdoor premises, industrial I construction areas (outdoor), 

mulch, nonagricultural outdoor buildings/structures, nonagricultural rights-ofway/fencerowslhedgerows, non-agricultural uncultivated areas/soils, paths/patios, paved areas 

(private roads/sidewalks), nursery stock, ornamentals, and recreational areas. 

Page2 
FORMULATIONS AND APPLICATION METHODS 

Oxyfluorfen is formulated as an emulsifiable concentrate, granular, ready-to-use solution, 

soluble concentrate, and flowable concentrate. It is applied as band treatment, broadcast, and by 

chemigation. Application equipment includes handheld sprayers and tractor mounded 

conventional ground sprayers. 

HISTORY OF OXYFLUORFEN AND BEAD PRODUCTS 

Oxyfluorfen was first registered for use in the United States in 1979 for pre and post-emergent 

control of broadleaf and grassy weeds in a variety of field, fruit, and vegetable crops, 

ornamental, as well as non- agricultural sites. There was a RED on this chemical in 2002 

(http://www.epa.gov/oppsrrdl/REDs/oxyfluorfen red.pdO. 

BEAD prepared a Screening Level Usage Analysis (SLUA) in April2014. A search of the 

BEAD database for previous BEAD products for oxyfluorfen indicates that there are no records 

of prior BEAD benefits assessments or emergency exemption requests over the past 1 0 years for 

oxyfluorfen. Note that a lack of emergency exemption requests does not indicate the relative 

importance of the chemical. 

USAGE 

Agricultural Uses 

Usage Trends 

For the years from 1998 to 2012, oxyfluorfen annual agricultural usage averaged 1.2 million 

pounds of active ingredient (a.i.) treating an average of2.5 million acres, for an overall average 

application rate of0.48 pounds a.i. per acre. (Proprietary data, 1998-2012). 

The usage of oxyfluorfen in terms of pounds applied has been basically constant, with a slight 

decrease when comparing total pounds applied over the time period from 1998 to 2012 (Figure 

1 ). Over the same time period the total acres treated (TAT) has trended upwards since 1998 

(Figure 2). Over time the number of acres treated has increased as the number of pounds applied 

has shown a downward trend especially since the 2002 RED which may indicate mitigation 

measures with rate reductions have taken effect (Tables 3 and 4). 

Page 3 
Figure 1. Total Pounds of Oxyfluorfen Applied (1998-2012) 

1,600,000 

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Figure 2. Total Area treated (TAT) of Oxyfluorfen in Acres (1998-2012) 

3,500,000 

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The rankings and percentages ofthe top crops (Table 1) and states (Table 2) have not 

significantly changed before and after the RED was issued in 2002. 

Page4 

N 

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Table 1. Crops with Highest Use of Oxyfluorfen in Terms of Percent of Total Lbs. 

Applied for Years 1998-2002 (before the RED) and 2008-2012 (after the RED) and 

P ercen tC rop T rea td e . 

1998-2002 (pre-RED) 2008-2012 (post-RED) 

Crop %Lbs Crop %Lbs %Crop 

Treated* 

Almonds 34 Almonds 36 65 

Wine Grapes 20 Wine Grapes 20 35 

Pistachios 9 Walnuts 11 55 

Walnuts 8 Pistachios 6 50 

Other 29 Other 27 - Source: EPA Proprietary Data, 1998-2012 

*Percent Crop Treated is based on proprietary data for the years 2004-2012. 

Table 2. States with Highest Use of Oxyfluorfen in Terms of Percent of Total Acres 

Treated (TAT)for Years 1998-2002 and 2008-2012 

1998-2002 (pre-RED) 2008-2012 (JJost-RED) 

State %Lbs State %Lbs 

California 91 California 93 

Washington 3 Washington 3 

Other 6 Other 4 

Source: EPA Proprietary Data, 1998-2012. 

Agricultural Usage: Top Crops and application Rates 

Table 3. Oxyfluorfen Usage on Top Crops and Average Application Rates from 1998-

2002 

Crop Total Total Acres Average AI Rate 

Pounds Applied Treated* (lbs AI/acres) 

Almonds 2,300,000 3,400,000 0.685 

Wine Grapes 1,400,000 1,500,000 0.909 

Pistachios 600,000 600,000 1.130 

Walnuts 500,000 800,000 0.710 

*Total Acres Treated sums all acres treated for a crop, including those acres that receive 

multiple treatments. 

Source: EPA Proprietary Data, 1998-2002. 

Page 5 
T a bl e 4 . 0 xyj fl uo rti en U sa2e on T C op rops an dA vera2e A ~PP1ICa r f Ion Rt a es f rom 2008 -2012 

Crop Total Total Acres Average AI Rate 

Pounds Applied Treated* (lbs AI/acres) 

Almonds 2,000,000 5,100,000 0.406 

Wine Grapes 1,100,000 1,500,000 0.767 

Pistachios 400,000 600,000 0.614 

Walnuts 600,000 1,400,000 0.449 

*Total Acres Treated sums all acres treated for a crop, mcludmg those acres that recetve multtple 

treatments. 

Source: EPA Proprietary Data, 2008-2012 

The application rates have decreased for the years of2008-2012 (Table 4), compared to the 

1998-2002 (Table 3) time span. 

Agricultural Use Intensity of Oxyfluorfen. 

Another measure of usage is the use intensity. In this analysis, the use intensity is expressed as 

the average annual amount (in pounds) of the active ingredient applied per 1000 acres of crop 

acres grown. This differs from the application rate, which is expressed as the pounds a.i. applied 

per treated area. Figure 3 spatially represents the use intensity of oxyfluorfen in the United States 

during 2008-2012 timeframe. Oxyfluorfen is registered on for use on a wide variety of fruit, tree 

nut and vegetable crops. The highest number of pounds applied by crop is on almonds followed 

by grapes, walnuts and pistachios in that order. Figure 3 shows that the highest use intensity is 

found in California, with more than 8 lbs oxyfluorfen per 1,000 crop acres grown. That is 

probably because of the large amount of tree nuts and grapes that are commercially grown in 

California. Following California, the highest use intensities are found in Washington, Oregon, 

Arizona, Louisiana, New York and Georgia, with 0.5 to 8 pounds. 

Page 6 
Figure 3. Annual average agricultural use intensity of oxyflourfen (2008-2012). 

Pounds Active Ingredient 

per 1,000 Crop Acres Grown 

0NoData 

0 <0.2 

0.2-0.5 

. 0.5-8 

- >8 

The map included herein is primarily for the use of the risk assessors in the Environmental Fate 

and Effects Division. 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 risk assessors are interested in the amount of a pesticide 

used across agricultural land. The calculated values presented in the map are not equivalent to 

an application rate (lb ai/ 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 applied) 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 that produce the majority of the crop. Although 

the surveys capture most of the use of a particular active ingredient in agriculture, there are 

several limitations to these surveys. 

Page 7 
Non-agricultural Usage 

Table 5. Oxyfluorfen Non-A~ ricultural Usa2e in Pounds A. I. ( 2002-20121 

Site 2002 2004 2006 2012 

Turf and Ornamental N/A NIA NIA 108,000 

Nurseries 107,000 84,000 71,000 

N/ A = Not Available 

Source: Proprietary Data, 2002-2012 

Use of oxyfluorfen on nursery stock has been declining since 2002 based on the available 

proprietary data as seen above (Table 5). 

BIOLOGICAL ASPECTS RELEVANT TO OXYFLUORFEN 

N/A . 

Oxyfluorfen is a broad spectrum contact type herbicide in the diphenyl-ether family. It is applied 

as pre-emergent and post-emergence treatments for control ofbroadleafweeds and some grass 

weeds in many crops listed above. When applied pre-emergence it provides residual weed 

control. Oxyfluorfen is readily absorbed by leaves of most weed species and very little is 

absorbed by the plant roots. According to Weed Science Society of America (WSSA) 

classification ofmode of action ofherbicides, oxyfluorfen is included in Group 14 (PPO 

inhibitors). It inhibits the enzyme protoporphyrinogen oxidase (WSSA, Undated). Inhibition of 

this enzyme interferes with chlorophyll production resulting in a rapid bleaching, necrosis and 

desiccation of susceptible weeds (Herbicide Handbook, 2014). 

ROLE OF OXYFLUORFEN IN PEST MANAGEMENT 

Oxyfluorfen is applied for the control of a broad spectrum of weeds on agricultural and nonagricultural sites. There are a number of crops that rely on the use of this herbicide for the 

control of many problematic weed species. From 2008 to 2012, about 36 percent of the almond 

crop was treated on average and for grapes about 20 percent of the crop was treated with 

oxyfluorfen. These and other high value crops require good weed management for optimum 

yield and quality. As an example, little mallow (Malva parviflora), a weed known to be a 

problem in orchards and vineyards, can be controlled effectively by applying oxyfluorfen or 

oxyfluorfen + glyphosate (University of California IPM Guidelines, 2014 (1)). Although 

almonds and grapes are the top crops for oxyfluorfen in terms of pounds and acres treated, 

oxyfluorfen is also used on garlic and onions where weed control is important as they are slowgrowing, shallow-rooted crops that can suffer severe yield loss from weed competition. 

Oxyfluorfen is registered as a post-emergent herbicide in onion. It controls small broadleaf 

weeds and some grasses. Oxyfluorfen (Goal2XL) formulation is used at the two- to four-leaf 

stage of the crop, but the Goal Tender formulation can be used at the 1st true leaf stage. 

(University of California IPM Guidelines, 2014 (2)). Oxyfluorfen is also used for weed control 

in gardens and landscape management (Univ. of California IPM, 2014 (3)). 

Page 8 
According to the International Survey of Herbicide Resistant Weeds, currently, only biotypes of 

two weed species; common ragweed (Ambrosia artemisiifolia), and tall waterhemp (Amaranthus 

tuberculatus) are reported to be resistant to the mode of action of oxyfluorfen in the United 

States (Heap, Undated). However, it is not clear whether the resistance of these 2 weeds affects 

the use of oxyfluorfen in the United States. 

DATA NEEDS 

The Agency currently does not have important information on oxyfluorfen. Obtaining the 

following information may improve future assessments conducted by the Agency related to the 

use and importance of oxyfluorfen. 

Non Agricultural Use 

• National·poundage applied in a yearly basis on the rights-of-way and other nonagricultural use sites would be useful to our work. 

REFERENCES 

Heap, I. Undated. The International Survey of Herbicide Resistant Weeds. Online Publication. 

2014. Available at: www.weedscience.org. Accessed on Feb 12, 2014 

Proprietary Data, 1998-2012. 

University 'of California. 2014 (1). UC Pest Management Guidelines. Almond. Online 

Publication. Available at: http:/ /www.ipm. ucdavis.edu/PMG/r3 7002ll.html. Accessed on 

Sep. 24, 2014. 

University of California. 2014 (2). UC Pest Management Guidelines. Onions and Garlic. Online 

Publication. Available at: http://www.ipm.ucdavis.edu/PMG/r58470011l.html. Accessed 

on Sep. 22, 2014. 

University of California. 2014 (3). Weed Management in Landscapes. Online Publication. 

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn744l.html. Accessed on Oct. 28, 

2014. 

USEPA. 2002. Registration Eligibility Decision (R.E.D.) for Oxyfluorfen. Online 

Publication. Available at: http://www.epa.gov/oppsrrdl/REDs/oxyfluorfen red.pdf. 

Accessed on Sep. 23rd, 2014. 

USEPA Oxyfluorfen Screening Level Usage Analysis (SLUA), April, 2014. 

WSSA (Weed Science Society of America). Undated. Summary of Herbicide Mechanism of 

Action. Online Publication. 

Available at: http://wssa.net/wp-content/uploads/WSSA-Mechanism-of-Action.pdf. 

Accessed on Sep. 23, 2014. 

Page 9 
APPENDIX A 

The map included herein is primarily for the use of the risk assessors in the Environmental Fate 

and Effects Division. The map provides a very broad geographical view of the amount (in 

pounds) of the active ingredient applied 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./A). 

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 CRDs allow for a sample to be collected that represent a much larger 

area with relatively homogeneous agricultural characteristics. 

The numerator (annual average pounds applied) is based on private market surveys of pesticide 

use in agriculture averaged over the last five years (Proprietary Data, 2007-2011). These surveys 

cover about 60 crops and are targeted in states that produce the majority of the crop. Although 

the surveys capture most of the use of a particular active ingredient in agriculture, there are 

several limitations to these surveys. · 

• States with minor production of a surveyed crop are not sampled 

• 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 CRDs that show no usage may actually have a small 

amount of the active ingredient being used. 

The denominator (1,000 Acres of land in farms) was selected from the Census of Agriculture 

(USDA, 2007) to represent agricultural acreage that is actively managed and includes most of the 

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 Forest Service, thus it is an underestimate of the land being 

managed for agricultural purposes. 

Page 10 
The 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. 

Scale and units of measurement do matter and may be different between maps. 

Page 11