UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MAR 112015 

' 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

BEAD Chemical Profile (BCP) for Registration Review of Pinoxaden (147500) 

Sunil Ratnayake, Ph.D., Biologist ~-" 1,., _ ri _ 

Biological Analysis Branch ~ c '~1 V'\ 4 ~ 

Jihad 

Science 

Alsadek, 

Information 

Ph.D., 

and 

Economist 

Analysis Branch 

i/ LJ /}z- Jf ~ 

Biological 

Economic 

Derek Berwald, 

Analysis 

and Economic 

Ph.D., 

Branch 

Economist 

Analysis 

~ 

Division (7503P) 

Diann Sims, Chief ~rttl"-l~u,/1144 -.v 

Science Information and Analysis Branch 

Economic 

Timothy Kiely, 

Analysis 

Chief 

Branch ~ ~ i 

Biological and Economic Analys · Division ( 50 ) 

TO: Miguel Zavala, Chemical Review Manager 

Risk Management and Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel Date: February 18, 2015 
SUMMARY 

Pinoxaden was first registered in the United States in 2005 (USEP A, 2005). This selective and 

systemic herbicide belongs to the phenylpyrazolin family. Pinoxaden is applied as a postemergence treatment for the control of annual grass weeds and certain broad leaf weeds in 

barley, winter wheat, and spring wheat, including durum. Pinoxaden can be tank mixed with 

compatible herbicides to broaden the weed control spectrum in small grain production. 

Based on private market usage data from 2006-2012, usage of this herbicide averaged 

approximately 165,000 pounds active ingredient (a.i.) applied annually on approximately 

3,685,000 acres treated. The average a.i. rate over this time period is 0.045 pounds a.i. /acre. 

There are no reported usage data for non-agricultural use sites. On the basis of2008 to 2012 

proprietary data, on average the highest usage (pounds a.i. applied) of this herbicide was 

observed in North Dakota. According to the available usage data in terms of percent of crop 

treated, 30 percent of barley and 5 percent of wheat are treated with pinoxaden. 

INTRODUCTION 

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

the pest management roles and quantitative usage information for pinoxaden. The BCP includes 

summaries of previous BEAD products and available public and/or private use and usage data 

for pinoxaden to describe its role in pest management. Additional information on use is 

available in the pinoxaden LUIS Label Data Report. Information provided in this BCP may be 

used by stakeholders (e.g., users and registrants), OPP risk assessors, OPP risk managers, and the 

general public during the Registration Review process of this pesticide. 

USE SITES 

Agricultural Use Sites 

Pinoxaden registered agricultural use sites include: barley, spring wheat, and winter wheat. 

FORMULATIONS AND APPLICATION METHODS 

Pinoxaden is formulated as an emulsifiable concentrate, flowable concentrate and soluble 

concentrate/liquid. Pinoxaden is applied post emergence for control of grass weeds in wheat 

(including durum) and barley. Pinoxaden is applied once per crop season using ground and aerial 

application equipment. 

HISTORY OF PINOXADEN and BEAD PRODUCTS 

Pinoxaden is an herbicide registered for use in the U.S. since 2005. A Screening Level Usage 

Analysis (SLUA) was prepared by BEAD for pinoxaden in 2014 that provides national level 

poundage applied by active ingredient (a.i.) and percent crop treated (PCT) data for crops for 

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which usage data are available. For pinoxaden, the agricultural sites with the highest average 

lbs. a.i. used annually were wheat (100,000 lbs. a.i.) followed by barley (40,000 lbs. a.i.). In 

terms of the percent crop treated, barley is 30 percent treated and wheat is 5 percent treated with 

pinoxaden. The high percent crop treated for barley may indicate high benefits for this crop, or 

at the very least, a high reliance on pinoxaden to control weeds in barley. 

A search of the BEAD data base for previous BEAD products for pinoxaden indicates that 

BEAD has not evaluated pinoxaden since early in its registration, when reviews on the efficacy 

of pinoxaden against barnyard grass were made to support the addition of barnyard grass to the 

U.S. label. 

USAGE 

Agricultural Usage 

Based on private market usage data from 2006-2012, usage averaged approximately 165,000 

pounds active ingredient (a.i.) applied annually on approximately 3,685,000 acres treated. The 

average a.i. rate over this time period is 0.045 pounds a.i. /acre. Figure 1 presents pinoxaden 

usage in pounds a.i. over the 2006-2012 timeframe. Figure 2 presents total area treated in acres 

over the same time period. The data show that the use of pinoxaden increased significantly 

between 2006 and 2008 and was stable thereafter. (Proprietary Data, 2006-2012). 

Figure 1. Pinoxaden Usage in Pounds Active Ingredient (2006-2012) 

250,000 

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Years 

Source: Proprietary Data, 2006-2012 

Page 3 
Figure 2. Pinoxaden Total Area Treated in Acres (2006-2012) 

5,000,000 

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Source: Proprietary Data, 2006-2012 

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The major agricultural use of pinoxaden during the 2008-2012 time frame was on wheat (spring 

and winter) and barley in North Dakota, Montana and Idaho. Tables 1 and 2 show the crops and 

states where pinoxaden is applied. Most of the use (77 percent of pinoxaden use) is in wheat, 

with the majority of that use in spring wheat. Most of the pinoxaden use is in states with 

significant acreage of wheat and barley, as shown in Table 2. Although more of the use is on 

wheat, pinoxaden may be more important on barley, where a larger portion of the much smaller 

crop is treated, as mentioned above. Wheat acreage is· substantially larger than barley acreage, 

which is why the majority of use is on wheat, even though more of the barley crop is treated. 

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in Terms of Pounds A lied 2008 - 2012 

Percent of Total Pounds A lied 

62 

23 

Winter Wheat 15 

Source: Proprietary Data, 2008-2012 

Table 2. Share of Pinoxaden Use by State in Terms of Pounds Applied (2008 - 2012) 

State Percent of Total Pounds Aoolied 

North Dakota 45 

Montana 24 

Idaho 10 

Other* 21 

Source: Proprietary Data, 2008-2012 

*Other states includes Minnesota, Tennessee, Washington, Texas, Arkansas, Oklahoma, Colorado, North Carolina, 

Kentucky, South Dakota, Wyoming, Missouri, Virginia, Nebraska, Oregon, Kansas, California, Utah, Georgia, 

Michigan and Pennsylvania. 

Application Rates 

The average a.i. rate for the top crops in terms of average annual pounds a.i. applied was highest 

on wheat both spring and winter at 0.05 lbs. a.i. per acre and lowest for barley at 0.04 lbs. a.i. per 

acre, as shown in Table 3. 

T a e . bl 3 p· moxa d en u se on T C op rops an dA verage A I R .. a t e, 2008 -2012 

Average Annual Average Annual Total Crop Pounds AI Area Treated * Applied 

Barley 46,000 1,037,000 

Wheat, Spring 123,000 2,725,000 

Wheat, Winter 29,000 62·1,000 

*Total Acres Treated swns all acre treatments for a crop. 

Source: Proprietary Data, 2008-2012 

Geographic Distribution of Pinoxaden Use 

AI Rate (lbs AI/acres) 

0.04 

0.05 

0.05 

Figure 3 provides a very broad geographical view of the average annual amount (in pounds) of 

pinoxaden applied per 1,000 acres of crop acres grown. The calculated values presented in the 

map are not equivalent to an application rate (lbs. a.i./a), therefore, the map may show areas of 

high use intensity that do not necessarily correspond to the states listed in Table 2 since those are 

the states with the highest use of pinoxaden based on pounds active ingredient applied. 

However, in this case, the map does demonstrate that North Dakota and Montana which account 

for 69 percent of pinoxaden usage in terms of pounds a.i. applied are also the states with the 

Page 5 
highest use intensity. 

As shown in the map, these states depict a high use intensity of acres treated with pinoxaden. 

Please see Appendix A for a more detailed explanation of the information presented on the map. 

Figure 3. Annual average agricultural use intensity of Pinoxaden (2009-2013). 

Pounds Active Ingredient 

per 1,000 Crop Acres Grown 

c:::J No Data 

LJ <0.05 

CJ o.05 - 0 .1 

0.1 - 0.5 

. 0.5-1 

- >1 

(Source: Proprietary Data) 

Page 6 
BIOLOGICAL ASPECTS RELEVANT TO PENOXADEN 

Pinoxaden belongs to the phenylpyrazolin family of herbicides (Group 1). This is a selective and 

systemic herbicide used as a post-emergence treatment and it controls economically important 

annual grass weed species and certain broadleaf weeds in barley and wheat production. 

Pinoxaden is rapidly absorbed by the weed foliage and translocated to the growing points. The 

mechanism of action of this herbicide is inhibition of Acetyl CoA Carboxylase enzyme 

(ACCase) (WSSA, Undated). This enzyme interferes with the synthesis of membrane lipids. 

Susceptible weed species generally stop growing within a few days after the application. Leaf 

chlorosis and necrosis develop within 1 to 3 weeks after the treatment and weeds are completely 

controlled within five weeks (Herbicide Handbook, 2014). 

ROLE OF PINOXADEN IN PEST MANAGEMENT 

Pinoxaden is an important herbicide available for weed control in barley, winter wheat, and 

spring wheat including durum. Pinoxaden has an excellent crop safety and controls many 

troublesome grass weeds such as: wild oat (Avenafatua), volunteer oat (Avena sativa), green 

foxtail (Setaria viridis), yellow foxtail (Setaria glauca), giant foxtail (Setariafaberi), Italian 

ryegrass (Lolium multiflorum), Persian darnel (Lolium persicum), barnyard grass (Echinochloa 

crus-galli), Canarygrass (Phalaris spp.), wild proso millet (Panicum miliaceum), and wind grass 

(Apera spp.) (Axial XL® Product Label, 2014). In addition, pinoxaden can be tank mixed with 

other compatible herbicides to increase the weed control spectrum in barley and wheat 

production (Axial XL® Product Label. 2014). Tank mixing ofpinoxaden with other herbicides 

with different modes of action helps on minimizing the development of herbicide resistance 

weeds in wheat and barley production. 

As described under the usage section, the percent of crop treated with pinoxaden for barley and 

wheat were 30 percent and 5 percent, respectively. Pinoxaden effectively eradicate major classes 

of grass weeds, leading to a substantial increase in crop yield. Grassy weeds including wild oat, 

cheatgrass, green foxtail, and Persian darnel are among the most serious weed problems to many 

barley growers (Univ. of Montana, Undated). Control of these weeds may contribute to the 

relatively high present of barley treated with pinoxaden. 

According to the international survey of herbicide resistant weeds in the United States 15 weed 

species have developed resistance to the Group 1 herbicides. However, presence of only 2 weeds 

species; Italian ryegrass (Lolium perenne ssp. multiflorum, and green foxtail (Setaria viridis) 

with resistance to pinoxaden have been reported in the. United States (Heap, Undated). 

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DATA NEEDS 

Currently, no data need is observed for this chemical. · 

APPENDIX A 

The map included herein 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 air. /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, 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. 

• 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. 

Page 8 · 
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 

lireas 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. 

The reader should pay particular attention to the figure legends and realize that a map prepared 

for a particular pinoxaden is not directly comparable to a map prepared for a different pinoxaden. 

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

REFERENCES 

Axial XL® Product Label. 2014. Syngenta Crop Protection LLC. P. 0. Box 10300, North 

Carolina, 27 419. Online Publication. Available at: 

http://www.cdms.net/LDat/ld9M9000.pdf . Accessed on Feb. 13, 2015. 

BEAD, 2014. Pinoxaden Screening Level Usage Analysis. Biological and Economic Analysis 

Division, Office of Pesticide Programs, US Enyironmental Protection Agency. November 

17, 2014. 

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

Available at: http://www.weedscience.org/summary/ResistbyActive.aspx. Accessed on 

January 28, 2015. 

Herbicide Handbook. 2014. 10th edition. Weed Science Society of America. Pinoxaden. Pp 

355-356. 810 E. 10th Street, Lawrence, KS 66044-8897. 

Montana State University. (Undated). Montana Barley Production Guidelines. Online 

Publication. Available at: 

http://www.msuextension.org/carbon/Documents/ag%20barley%20prod.pdf. 

Accessed on Feb. 27, 2015. 

Proprietary Data, 2006-2012. 

USDA- NASS, 2004. Available at: 

http://www.nass.usda.gov/Statistics by Subject/index.php?sectoi=CROPS. Accessed on 

February 20, 2015. 

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USEPA. 2005. Pinoxaden Conditional Registration. Available at: 

http://www.epa.gov/oppOOOO I /chem search/reg actions/registration/fs PC-14 7500 0 lJul-05.pdf. Accessed on January 28, 2015. 

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

Action. Online Publication. Available at: http;//wssa.net/wp-content/uploads/WSSAMechanism-of-Action.pdf. Accessed on January 28, 2015. 

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