UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WAS H INGT ON D.C., 20460



### NOV 2

_ 5 2013 OFFIC E OF CHE M ICA L SAFETY AND POLLUTION PREVE N TION MEMORANDUM SUBJECT: FROM:

THRU:

TO: BEAD Chemical Profile for Registration Review: Flucarbazone-sod ium (114009) Sunil Ratnayake, Ph.D., Biologist

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### An**~~ n~h** **,9 ~**  - \ Rafael Prieto, ' Environmen f a{ Protection Specialist Science Informa h on and Analysis Branch T J Wyatt, Economist**~** 1 ,/

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## I'lL Economic Analysis Branch 

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## 19 ,)w.n&r- J(JI -$ Biologic and Econo m ic Analysis Divisioh (7503P) Arnet Jones, Chief Biological Analysis Branc Diann Sims, Chief

# ~~ Science Information and Analysi s Branch Tim Kiely, Chief 

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# ~ Economic Analysis Branch V "\ Biologic and Economic Analysis ivision (7503 Jol ene Trujillo, Chemical Review Manager Risk Management and Implementat ion Branch 5 Pesticide Re-evaluation Division (7508P)
Product Review Panel date: May 22, 2013 SUMMARY Flucarbazone-sodium is registered for use on spring wheat, including durum, and winter wheat, grasses grown for seed, o n conifers (plantations/nurseries), and on ornamental lawns and turf. Based on available usage information, flucarbazone-sodium may play a relatively important role

### in the control of weeds in spring wheat production , where about ten percent of the crop is treated annually. In winter wheat, only about one percent o f the crop is treated annuall y, suggesting that flucarbazone-sodium plays a relative ly minor role in weed control. However, recent data show that use in w inter wheat may be increasing over the past several years. While many weed species have develop ed resistance to ALS

-inhibiting herbicides such as flucarbazone-sod ium, the fairly consistent use of thi s herbicide in wheat production for th e past several years does not suggest that growers are having any particular resistance problems at this time that would deter them from using it. Flucarbazone-sodium may play a role 

### in resistance management as a tank mixed product. Furthermore , as a post-emergence herbicide used in wheat production, it can provide growers with useful options if pre-plant or pre-emergence herbicides do not provide adequate co ntro l of weeds. Growers can use this herbicide as a post-emergence application to control competing weeds present in wheat fields such as wild oats, foxtails , and other grass and broadleaf weed species. However, there are several alternatives to flucarbazone

- sodium that can be applied as post-emergence treatments for the control of s imilar weeds. BEAD does not have any information to assess the pest management role of flucarbazonesodium in grass grown for seed or in conifer and turf.
INTRODUCTION 

### The Biological and Eco nomic Analys is Division (BEAD) Chemical Profile (BCP) provides an overview of the pest management ro les and quantita tive usage information for flucarbazone

sodium
. The BCP includes summaries ofprevious BEAD products and avail able public and /o r pr ivate use and usage data for flucarbazone-sodium to describe the role of this chemical in pe st management. Additional information on use i s avail able in the flucarbazone-sodium PRD Label Data Report and the Screening Level Usage Analysis. Information provided in this BCP may be used by stakeholders (e
.g . , users and registrants), OPP ri sk assessors and risk managers, and the general public during the Registration Review process of this pesticide. The document is based on information and data avail able to BEAD as of October 2013. Flucarbazone-sodium was first registered in the U.S. in 2000. This herbicide is desi gnated as a reduced risk herbicide. Flucar bazone-sodium belongs to the Sulfonylaminocarbonyltriazolinone group of herbicides (Weedscience
.org, 2013) and it is a systemic herbic ide used for the postemergence control of wil d oat , green foxtail, and other grass and broadleaf weeds found in crop production fields and other sites described un der th e use sites. According to the Weed Science Society of America (WSSA) mechanism of action classification, flucarbazone

- sodium belongs to the group 2 herbicides. The mechanism of action of this group of herbicides is inhib ition of the enzyme ace to lactate sy nthase (ALS) enzyme which i s al so call ed the acetohydroxyacid synthase (AHAS). Inhibition of this enzyme interferes wi th the biosynthesi s of branched

- cha in amino acids such as valine, leucine, and isoleucine and initiates a cascade of events leading to the death of susceptible weeds
. 2USE SITES Agric ultural Use Sites Flucarbazone-sodium is registered for use in spring wheat, including durum, winter wheat, grasses grown for seed, and conifers (plantations/nurseries)
. Non-Agricu ltural Use Sites Flucarbazone-sodium is registered for use on ornamental lawns and turf, including go lf courses. COMMON FORMULATIONS AND APPLICATION METHODS Flucarbazone

- sodium is formu l ated as water dispersible granul es, emulsifiable concentrate, and so luble concentrate. Use in grass grown for seed is lim ited to so lub le concentrate and use in conifers and turf i s li mited to the emulsifiable concentrate. This chemical i s applied as broa d cast and spot treatment. According to the information provided on the product label of Everest ® herbicide, aerial and groun d app li cations are recommended as the application methods of thi s herb ic ide
. HIST ORY OF BEAD ASSESSMENTS FOR FLUCARBAZ ONE-SODIUM B EAD has not previously assessed the benefits associated with the use o f flucarbazone

- sodium. USAGE Based on private market pesticide usage data from 2008

-20 1 2 , flucarbazone

- sodium's annual agricultural usage averaged 36,000 pounds of active ingredient (A. 1.) treatin g an average of2.4 million acres, for an average app lication rate of 0
.0 1 5 pounds A. I. p er acre. Use in grass seed, conifer, and turf production i s not included in this estimate as usage surve y data do not cover these si tes . USE TRENDS Figure 1 shows the overa ll tre nd offlucarbazone-sodium use from 2001 through 2012. Use has ri sen steadily si nce registration in 2000. Use fluctuated aroun d an average of 30 , 000 pounds A. I. applied per year in the latter half of the decade , but recent data su ggests the u pward trend may cont inue (Prop rietary data, 2001-20 12)
. Thus , the average use reported here may underestimate future use.

3Fi re 1. Total Pounds of Flucarbazone-sodium A

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 (Source: Proprietary data, 2001-2011) During thi s timeframe , spring wheat accounted for the largest percentage of usage in terms of total pounds of A. I. applied and total area treated. See Table 1 below. The average application rate of0.015 lb A.I. per acre i s approximately the same for both winter and spring wheat. Less than 0.5 percent of the total amount was applied to fallow and barley according to survey data. These are not registered use sites and th e survey results could indicate misuse, response errors in the survey, or reflect the respondents' interpretation of the question (e.g., fallowed land to be planted w ith wheat). Table 1. Flucarbazone-sodium's Top Crops in Terms of Avg. Lbs . Applied & TAT (2008- 2012) 

### Crop Pounds Applied (A.I) Total Acres Treated Wh eat, Sprin g 77.0% 77.8% Wheat, W inter 22.3% 21 .9 % (Source: Propnetary data , 2008-2012) Over the 2004 to 2011 time period, about five percent of U.S. wheat acreage was treated each year, on average, with flucarbazone-sodium (BEAD, 2011). According to data from the U.S. Department of Agriculture (NASS, 2010), flucarbazone-sodium has been used on less than one percent of the U.S
. winter wheat acreage. Use is somewhat more prevalent on spring wheat, with less than five percent of durum wheat treated and between seven and nine percent of acres in other spring wheat.

4

### As seen on Table 2 below, flucarbazone

- sodium's top states in terms of both pounds (lbs
.) applied and total area treated (TAT) are North Dakota, Montana, and Minnesota. These three states accounted for about 80 percent oftotal acres planted to spring wheat in the U.S. between 2009 and 2011 (NASS, 2012). There is substantial acreage of w inter wheat in Montana as well
. 

### Table 2 . Flucarbazone-s odium's Top States in Terms of Avg. Lbs. App lied & 

### TAT (2008- 2012) STA T E Pounds Applied Total A cr es T reated 

### North Dakota 63.0% 63.4% Montana 15.0% 13.5% Minnesota 5
. 8% 6.8% (Source : Proprietary data, 2008

- 20 12) 

### Figure 2 depicts flucarbazone

- sodium's agricultural usage, in terms of pounds applied , for winter and spring wheat (proprietary data, 2001

- 2012)
. Since about 2005, use in spring wheat has fluctuated from year to year, but does not appear to be trending up or down while use in winter wheat has been stable or increasing , especially in the most recent year data are available. 

### Fi ure 2. Pounds of Flucarbazone-sodium A lied on Major Cro s er Year

40,000 -.- -- - - ---- - ---- - --------------

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## "' -lbs applied, Spring Wheat

- - ·lbs app l ied, Winter Wheat



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0**+---.-- .--.---.** **--.--,---.--.---.- -.** **-- .--~**  2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Year Note : A minim um percentage of barley and fallow was treated with flucarbazone-sodium
. (Source: Proprietary data , 200 1 -20 12)

5Geographic Distribution of Flucarbazone-sodium Use Figure 3 depicts the regions of the United States where use offlucarbazone-sodium is reported. The map indicates the re lative intensity of use where th e use intensity is expressed as the pounds A 

### .I. applied per 1,000 acres of cultivated crop land. This differs from the application rate, which is expressed as the pounds A.I. applied per treated acre. The average application ra te for the period 2008-2012 is 0.015 pounds A. I. per acre, or 15 pounds A.I. per 1,000 treated acres. As shown in Figure 3, however, use intensity range is well u nder one pound per 1,000 acres of crop land
. The area of highest intensity is in North Dakota reflecting a relatively high percent of spring wheat treated with flucarbazone-sodium and a high proportion of s pr ing wheat in farmland. Relatively low intensity ofuse is shown in Kansas, Oklahoma, and Texas. These three states account for almost 50 percent of winter wheat acreage in the U.S. (NASS, 2012 ), but, as noted above , le ss than one percent of U.S
. winter wheat is treated with flucarbazone -sodium (NASS , 2010). 

### Figure 3 . Flucarbazone-sodium Usage by State (2008-2012)

Pounds Acitve Ingredient per 1,000 Crop Acres Grown 0No0at a 

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- 003 · 01 2

. 0
. 1 3 · 0.32

- > 0.3 2 See Appendix A for explanation of the methodology and data used to generate Figure 3, as well 

### as a discussion of data limitat i ons and uncertainties. 6CHEMICAL AND USE CHARACTERISTICS Flucarbazone

- sodium belongs to the sulfonylamin ocarbonyltriazolinone group of herbicides (Weedscience.org, 2013). Herbicides belong to this group inhibit the acetolactate synthase (ALS) enzyme which is also called the acetohydroxyacid synthase (AHAS)
. Inhibition ofthis enzyme interferes with th e bio-synthesis of branched chain amino acids (valine, leucine , an d isoleucine) in susceptible weeds (WSSA, 2013)
. Other major classes ofherbicides which inhibit this enzyme are imi dazo linones , pyrimidinylthiobenzoates, sulfonylureas, and triazo lopyrimidines. Variations on residual activity, crop selectivity, and spectrum of weeds controlled may be observed with the application of herbicides included in these classes (Univ. of Tennessee, 2013). The majority ofthese herbicides are systemic herbicides and they are active on annual and perennial weed species
. The major weed species controlled by :flucarbazone

sodium are green foxtail 

### (Setaria viridis), wild oats 

### (Avena sativa), barnyard grass 

### (Echinochloacrusgalli), brome species 

### (Bromus spp.), redroot pigweeds 

### (Amaranthus retrojlexus), wild mustard species 

### (Brassica spp.), curly dock 

### (Rumex crispus), and Pennsyl vania smart weed 

### (Polygonum pensylvanicum)
. Generally, injury symptoms occurring due to the applications of ALS inhibitors appear within a week after th e herbicide treatmen ts. Significant symptoms are chlorosis, purple leaf veins, and bottlebru sh appearance of root s in some weed spec ie s. Comp lete death of susceptible weed species may occur w ithi n two to three weeks after the herbicide app li cati ons . It has been reported that currently, 131 different weed species have developed resistance to ALS inhibiting herbicides in more than 400 locations in the world (Weedscience.org, 2013). Clodinafop, fenoxaprop, pinoxaden, and propoxycarbazone

- sodium are some of the herbicides that can be used as alternatives to control wild oats, Italian ryegrass, and other grass weed species in spr ing wheat production (Morishita and Lyon, 2012). Flucarbazone-sodium is applied as a post-emergence treatment (herbicide applied after the emergence ofthe cro p) in wheat. Generally, post-emergence treatments are highly effective when applied at t he seedling stage of weeds. The use ofpost
- emergence herbicides, including flucarbazone, is important when pre - plant or pre-emergence treatme nts do no t provide adeq uate weed control. The alternatives noted above can also be use post-e mergence. Furthermore, flucarbazone

sodium is used for the selective control of grass and broadleaf weed species in tolerant cool and warm season turf grass species. In addition, this herbicide is used for the growth management and seedhead s uppression of certain turf grass species (Align Product Label, 201 0). ROLE OF FLUCARBAZONE-SODIUM IN PEST CONTROL Given the low percentage of the crop treated, flucarbazone-sodium does not appear to play an important pest control role in winter wheat production. However, the relatively higher percentage of spring wheat treated suggests that :flucarbazone-sodium may be important for weed control in s pring wheat production. While many weed species have developed resistance to ALS-inhibiting herbicides such as :flucarbazone-sodium, the fairly steady u sage ofthis herbicide in wheat production for the past several years does not suggest that growers are facing resistance 7problems at this time. Flucarbazone

- sodium may play a role in resistance management, for example , in a tank mix in combinat ion with herbicides with different mechanisms of action. As a post-emergence herbicide , it can pro vide growers w ith useful options if pre-plant or pree mergence herbicides d o not provide adequate weed control. Flucarbazone-sod ium is likely to be an effective product for the co ntrol of wild oats , foxtails, Italian ryegrass, and other grass weed species found in wheat. However, it is not unique in either the weeds it cont rols or 

### in its u se as a post-emergen ce herbicide. B EAD does not hav e sufficient information on the u se of flucarbazone-sodium to assess its value in grass g rown for seed, in conifer production , or in turf. INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK ON FLUCARBAZONE-SODIUM The Agency c urrently does no t have important i nformat io n on so me uses of flucarbazone

sodium. To understand th e ro le o f flucarbaz one - sodium in the production of grass seed, conifers , and turf , and any benefits it provides u sers, useful information would includ e • acres treated and app li cation rates , • timin g and frequency of applications , and • target pest s REFERENCES Align Herbicide Product Lab el. 20 10. Arysta LifeS cience, North America LLC. 15401 Weston Parkway , North Ca rolina, NC 27513. Accessed on Nov , 5, 2013. BEAD. 2 01 3. Screen in g Le vel Us age Analys is . B iologica l and Eco nomic Analysis Div i sion, Office of Pest i cide Programs, U.S. EPA. Morishita, D. , and D. Ly on. 2012. Spring Wheat. Pacific Northw est Weed Management Handbook. E. Peachy, ed. Pacific Northwest Extens ion Pub li catio n , Oregon S tate University , Was hin gto n S tate University, and University of Idaho. Avai lable at htt p: // p nwhan dbooks.or g/weed/agro norni c/ cereal-grai n -cro p s /spring

- wheat. Accessed Date. May 1 5, 20 1 3. NASS. 2012. Crop Productio n , 201 1 Summary. National Agricultural Stati st ics Service, U.S
. Department of Agricu lture . January. Avail a ble at http: // usdaO l.library.corne ll .edu/usda/nass/ C ro pProdSu/ / 20 1 Os/ 20 1 2/CropP ro d S u- 0 l

- 12

- 2012.pdf. Accessed Da te. May 8 , 20 1 3.



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### NASS. 2010. 2009 Wheat Chemical Use. National Agricultural Stati stic s Service , U .S. Department of Agriculture. May
. Available at http: //www.nass.usda.gov/ Oata and Statistics/PreDefined Queries /2009 Wheat Chern Usage/index.asp
. Accessed Date. May 8 , 2013. Proprietary data, 2001

- 2011 Univ. of Tennessee. 2013
. Mode of Action Definitions. University of Tennessee , Knoxv ill e. Available at http: / /hortweeds.tennessee.edu/webapp/test/moa.htm
. Accessed Date May 6, 2013
. Weedscience
. org. 2013. International Survey of Herbicide Resistant Weeds. http: //www.weedscience.org/summary/home.aspx
. Accessed Date May 7 , 2013. WSSA. 2013
. Summary of Herbicide Mechani sm of Action. Weed Science Society of America. Availabl e at http: //wssa.net/wp-content/uploads / WSSA-Mechanism-ofAction.pdf
. Accessed Date May 8, 2013.

9

### Appendix A . Fluca rbazone Use 

### Intensity by State (2008- 2012) The map included herein i s primarily for the use of the risk assessors in the Environmental Fate and Effects Division. The map provides a very broad geographical v iew ofthe average annual amount (in pounds) of the active ingredient applied per 1,000 acres of crop acres grown. These data are inc luded in the maps because risk assessors are interested in the amount o f a pesticide used across agricultural land. The calculated values presented in the map are not equivalent to an application rate (lb ail 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 ofpe st icide use in agriculture averaged over the l ast five years (Proprietary Data, 2008-2012). These surveys cover about 60 crops and are targeted in states that produce the majority ofthe crop. A lthough the surveys capture most of the use of a particular active ingredient in agriculture, th ere are several limitations to these surveys.
• States with minor production of a surveyed crop are no t sampled • Not all types of pesticides are surveyed in every crop in every year • Many specialty crops with very sma ll acreages are not included in the survey The result of these limitations is that states that show no usage may actually have a small amount of the active ingredient being used. In some cases the d isplayed use intensity may be distorted because the surveyed crops and the reported pesticide usage may not accurately represent the actual pe sticide usage on the crops produced in the state . The denominator (1 ;000 crop acres grown) was also obtained from the same private market survey database
. The "Crop Acres Grown" variable represents the total acres grown in a given state of all of the surveyed crops. This value is independent of pesticide usage and pesticide registration. It is important to note that the surveyed crops (about 60) are sampled from states that are major producers of each crop. Therefore, there are cases where the actual crop acreage in a state is higher than that reported by crop acres grown in the survey because either that state and/or crop was not i ncluded in the s urvey. The reader should pay particular attention to the figure legends and realize that a map prepared for a particular chemical is not directly comparab le to a map prepared for a different chemical as the legend bins will likely be different.

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