UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MAR 12 2014 

OFFICE OF CHEMICAL SAFETY 

AND POLLUnON PREVENTION 

MEMORANDUM 

SUBJECT: BEAD Chemical Profile for Registration Review: Bispyribac-sodium (078906) 

FROM: 

THRU: 

TO: 

Monisha 

Biological 

Kaul

Analysis 

, Biologist 

Branch 

I: 10J1.h,J ~ ~ 

Cynthia Doucoure, Environmental Protection Specialist C . ~~~ .. c' 

Science Information and Analysis Branch 

Andrew Lee, Economist t (? j 

Biolog

Economic 

ical 

Analysis 

and Econom

Branch 

ic Analysis Divis n (7503P) 

· ~ 

Arnet 

Biological 

Jones

Analysis 

, Chief 

Branch rr-· /) -- "' ~ (;. . Diann Sims, Chief J{]~ Science Information and Analysis Branch 

Timothy 

Economic 

Kiely

Analys , Chis 

ie

Brancn 

f Q: lA/l~ . 

Biological and Economic Anal sis Division (75 ) 

Moana Appleyard, Chemical Review Manager 

Risk Management and Implementation Branch V 

Pesticide Re-evaluation Division (7508P) 

Product Review Panel date: November 27, 2013 

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INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

management roles of pesticides that are beginning to undergo registration review. The 

anticipated audience consists of the team of EPA staff currently evaluating the registration status 

of bispyribac-sodium, and eventually the general public. This document builds upon the data 

BEAD provides in the Label Use Information System (LUIS) reports and the Screening Level 

Usage Analysis (SLUA) to Registration Review teams. The document is based on information 

and data available to BEAD as of October 2013. 

Bispyribac-sodium is a post-emergence herbicide formulated as a wettable power or water 

soluble granule used to control grasses and weeds. This herbicide is in the Weed Science 

Society (WSSA) group 2 and has a mode of action of inhibiting acetolactate synthase (ALS 

inhibitor). Bispyribac-sodium is an herbicide that was registered in the U.S. on September 24, 

2001. 

HISTORY OF BEAD ASSESSMENTS FOR BISPYRIBAC-SODIUM 

BEAD prepared a Screening Level Usage Analysis (SLUA) in April 2013 that provided data on 

use ofbispyribac-sodium on rice in the U.S. during the 2004-2011 timeframe, which showed that 

an average of 4,000 pounds a.i. was applied annually to rice and that the average percent crop 

treated was 5%. 

COMMON FORMULATIONS AND APPLICATION METHODS 

Bispyribac-sodium is commonly formulated as a wettable powder or water soluble granule, 

packaged in water soluble bags, and applied as broadcast or surface sprays using ground or aerial 

sprayers. 

USE SITES 

Agricultural Use Sites: 

Bispyribac-sodium is registered for use on rice. 

Non-Agricultural Use Sites: 

Bispyribac-sodium is registered for use on golf course turfgrass and sod farms, as well as aquatic 

sites such as canals, drainage ditches, marshes, lakes, ponds, and reservoirs. 

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BISPYRIBAC-SODIUM USAGE 

Agricultural Usage on Rice 

According to proprietary market research surveys, bispyribac-sodium use on rice fluctuated in 

terms of pounds a.i. applied and total area treated throughout the 2002-2012 timefrarne as shown 

in Figures 1 and 2 below. The overall average a.i. rate of application during this period was 

0.026 lbs a.i. per acre. However, there was a slight increase in the average a.i. rate of application 

(0.029 lbs ai per acre) during the second half of the period (2008-20 12) due to a nearly 50% 

increase in pounds a.i.applied and a nearly 20% increase in total area treated as shown in Table 

1. 

Figure 1. Bispyribac-sodium Use on Rice: Pounds AI Applied, 2002-2012 

...: 

<i 

"0 "' 

c 

:I 

0 

Q. 

8,000 ....-------------------------

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 

Year 

Source: EPA Proprietary Data, 2002-2012 

Page 3 of8 
Figure 2: Bispyribac-sodium Use on Rice: Total Area Treated Applied, 2002-2012 

300,000 ..,..--- ----------------- -

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 

Year 

Source: EPA Proprietary Data, 2002-2012 

Table 1. Bispyribac-Sodium Use on Rice: Comparison of Usage between the 2003-2007 and 2008-2012 

Time frames 

Timeframe Av2 Lbs AI Total Area Treated A V2. A.I. Rate 

2003-2007 3,510 147,188 0.024 

2008-2012 5,196 180,492 0.029 

Source: Propnetary Data, 2003-20 12 

Agricultural Usage: Top States, 2003-2012 

Bispyribac-sodium was used predominantly in the states of California and Arkansas during the 

2003-2012 timeframe. During 2008 - 2012, Louisiana accounted for a smaller proportion of 

national use than in 2003 - 2007 (Table 2). The proportion of national use increased in Arkansas 

and Texas as shown in Table 2. Although the proportion of use in California has decreased 

slightly in 2008 - 2012 as shown in Table 2 the total pounds applied actually increased from a 

little over 9,000 lbs a.i. during the 2003-2007 period to nearly 12,000 lbs a.i. during the 2008-

2012 period. The a.i. rate of application in California was also above average in the second half 

while the rates of application in other states were below average. 

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Table 2. Comparison of States with Highest Use ofBispyribac-Sodium- Percent of Total Lbs. Applied 

between the 2003-2007 and 2008-2012 Timeframes 

2003-2007 2008-2012 

Average= 3,510 lbs/yr Average= 5,196lbs/yr 

State %Lbs A.I. Rate of State %Lbs A.l. Rate of 

Applicaton Applicaton 

California 52 0.052 California 46 0.038 

Arkansas 21 0.021 Arkansas 32 0.026 

Louisiana 13 0.012 Texas 14 0.011 

Other* 14 0.020 Other** 8 0.023 

*Other States in the 2003-2007 timeframe include MS, MO, and TX 

*Other States in the 2008-2012 timeframe include LA, MS, and MO 

Source: Propnctary Data, 2003-2012 

Agricultural Use Intensity of Bispyribac-Sodium on Rice in the U.S. 

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 1,000 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 bispyribac-sodium's use intensity in the U.S. on 

rice, which is relatively greater in California and Arkansas during the 2008-20 12 timeframe. For 

more information about this map, see Appendix A. 

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Figure 3. Annual Average Agricultural Use Intensity ofBispyribac-Sodium (2008-2012). 

Pounds Active Ingredient 

per 1.000 Crop Acres Grown 

c=J No Data 

c=J < 0.002 

.. 0.003- 0.025 

.. 0.026 - 0.055 

.. >0.056 

(Source: Proprietary Data, 2008-2012) 

Non-Agricultural Usage 

BEAD reviewed available data sources but did not find any data on non-agricultural uses of 

bispyri bac-sodi urn. 

BIOLOGICAL ASPECTS RELEVANT TO BISPYRIBAC-SODIUM 

Bispyribac-sodium is selective, postemergence herbicide. Although most ALS inhibitors are 

systemic, bispyribac-sodium can be used as a contact herbicide. According to the product label 

Regiment®, bispyribac-sodium may be applied in single or split application and alone or in a 

tank mix. Most applications require the use of a surfactant. 

Bispyribac-sodium is used to control many weeds in rice such as bamyardgrass/junglerice 

(Echinochloa crus-galli/Echinochloa colonum), watergrass (Echinochloa oryzoides), and 

momingglory (Ipomoea hederacea and Ipomoea Jacunosa) (Proprietary data, 2008-2012). There 

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are two weed species with reported resistance to bispyribac-sodium: annual bluegrass (Poa 

annua) and rice flatsedge (Cyperus iria) (Heap, 2013). In addition, there are many more reports 

of weed resistance to WSSA group 2 herbicides. Careful stewardship of this herbicide and other 

Group 2 herbicides is needed to delay herbicide resistance. 

ROLE OF BISPYRIBAC-SODIUM IN PEST MANAGEMENT 

Bispyribac-sodium provides late, postemergence weed control in rice production. Because of 

known resistance issues the use of this herbicide must be managed carefully. However, the use 

ofbispyribac-sodium has increased in rice production despite the documented weed resistance. 

California and Arkansas account for the majority of the bispyribac-sodium pounds applied to rice 

and are also the top two rice producing states in the U.S. (USDA NASS, 2013). Although use 

has increased overall (Table 1 ), only 5% ofrice is treated nationally on average with this 

herbicide, which indicates low importance to rice production nationally. 

INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK ON 

BISPYRIBAC-SODIUM 

The Agency currently does not have important information on bispyribac-sodium. Obtaining the 

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

use and importance of bispyribac-sodium: 

• Information on ornamental lawns and turf, including golf courses and sod farms, as well 

as aquatic sites such as canals, drainage ditches, mashes, lakes, ponds, and reservoirs, 

including pounds a.i. applied, application timing, application rate, application method, 

application frequency. 

• Importance ofbispyribac-sodium for fungal pests such as dollar spot. 

• Resistance management information related to the use and importance ofbispyribacsodium in rice production. 

REFERENCES 

EPA Proprietary Data, 2002-2012 

EPA, Bispyribac-sodium Screening Level Usage Analysis (SLUA), January 2013 

Heap, I. The International Survey ofHerbicide Resistant Weeds. Available at: 

www.weedscience.org. Verified: November 12, 20 13. 

USDA NASS, 2013. Acreage. Online: http://usdaOl.library.cornell.edu/usda/current/Acre/Acre06-28-2013.pdf. Verified: February 28, 2014. 

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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 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 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 of pesticide 

use in agriculture averaged over the last five years (Proprietary Data, 2008-20 12). 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 ofthese limitations is that states that show no usage may actually have a small amount 

of the active ingredient being used. In some cases the displayed use intensity may be distorted 

because the surveyed crops and the reported pesticide usage may not accurately represent the 

actual pesticide 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 included in the survey. 

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 as 

the legend bins will likely be different. 

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