UNITED STATES ENVIRONMENTAL PROTECTION AGE NCY

WASHI NGTON, D.C. 20460

FE3 24 2011

OFFICEOF CHEMICAL SAFETY

AND POLLUTIO N PREVENTION

MEMORANDUM

SUBJECT: BEAD Chemical Profile for Registration view: Thifensulfuron (128845)

,

Bill Phillips, II, Ph.D. j f

Biological Analysis Bran5f2

Rafael A. Prieto .72-t- f .-> n . Science Infonnatfon arl'd Analysis Branch r - Stephen Srneannan \

Economic Analysis Branch pP'\-

Biological and Economic Analysis Division (7503P)

Arnet Jones, Chief

Biological Analysis Branch

" Diann Sims, Chief f{tC."·.....~.",.V- -/ Science Information and Analysis Branch

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FROM :

TO : Kylie Rothwell, Chemical Review Manager

Risk Manage ment and Irnple:nentation Branch 3

Pesticide Reevaluation Divis:on (7508 P)

Peer Review Panel date: August 25, 2010

INTR ODUCTION

The purpose ofthis 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'thifensulfuron-merhyl", and eventually the genera l public . This document builds upon the data

already provided in the "Usage and Label Use Data Packages" that are also provided to

Registration Review teams by BEAD.

Thifensulfuron is an herbicide used in small grain (barley, flax, oats, safflower, triticale, and

wheat) and soybean crops for the control of small-seeded broadleafweeds. This chemical is in

the family of sulfonylurea (SU). The Herbicide Resistance Action Committee and Weed Science

Soc iety of America classify this herbicide in group 8.'22

• The mode of action is via the

inhibition ofthe plant enzyme acetolactate synthase (ALS). Currently, there are several weed

species resistant to herbicides in this famil y, including thifensulfuron.

USE SITES'

Below are the unique agricultural and non-agricultural use sites for thifensulfuron.

Agricu ltural Use Sites:

Agricultural fallow I idle land I conservation reserve, barley, cano la\rape,

com (unspecified), com - field, oats, rice, safflower (unspecified),

sorghum, soybeans (unspecified), sugar beet, triticale, wheat

'Non-Agrcultural Use Sites:

Cotton (unspecified), flax

COMMON FORMULATIONS AND APPLICATION METHODS

This chemical is formulated as dry flowable.

USAGE

Agricultural Use Sites

Based on private market pesticide usage data, the agricultural usage averaged almost 100,000

pounds active ingredient (A.I.) for about 10 mill ion acres from 1998-2008 (GfK Kynetec, 1998-

2008). The use of thifensulfuron, in total pounds A.L per year, over the 1998-2008 year span,

has been relatively constant with a slight increase in 2008.

I 3-(a-methoxy-e-methyl-I,3,S-triazin-2-ylcarbamoylsulfamoyljthiophene-2-carboxylie acid

2 Herbicide Resistant Action Committee

http://www.weedscience.orglsummary/ChemFami1 ySum.asp? lstActive=478&btnSub J'"'Go&IstHRAc3 IThis is a summaryof me usc sues. Please refer to me PRD Appendix A: Food'Feed & Non-Food/Non-Fccd u ses Considered in Registration

Review Work Planning for a comprebcnsive list

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140,000

From 1998-2008, the largest markets in terms oftotal pounds of active ingredient applied are:

winter wheat (51%), spring wheat (29%), barley (7%), soybeans (7%), and com (5%). (OlK

Kynetec, 1998-2008)

From 1998-2008, the largest markets in terms oftotal area treated are: winter wheat (39%),

spring wheat (27%), and soybeans (20%). (OlK Kynetec, 1998-2008)

The states with the most agricultural usage in terms of pounds AI applied are: North Dakota

(20%), South Dakota (7%), Washington (7%), Kentucky (7%), and lllinois (6.5%).

The states with the highest total area treated are: North Dakota (18%), South Dakota (7%),

Washington (7%), Illinois (7%), and Minnesota. (OlK Kynetec, 1998-2008)

USE TRENDS

The following graph provides usage trends, interm s of pounds applied, for thifensulfuron's

largest agricultural markets. The data in this section are provided forpreliminary scoping

purposes. Usage has been steady with an increase in 2008 primarily in spring wheat and corn.

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

j 0 Barley _ Corn 0 Wheat, Spr:ng 0 Wheat, Winter _ All Other C rops I

Note: "All OtherCrops" refers to Cotton, Dry BeanslPeas, Fallow, Pasture/Range, Rice,

Sorghum (Milo), Soybeans, Sunflowers, and Sweet Corn.

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BIOLOGICAL ASPECTS RELEVANT TO THE CHE:\IICAL TIIIFENSULFURONMETHYL

In order to broaden the spectrum ofthis herbicide. thi.ensulfuron is primarily sold in premixed

products or is used as a tank mix partne r with other herbicides. Weeds resistant to other

herbicides in this chemical family are also resistant to thifensulfuron. Resistant weeds include

species such as tall waterhemp (Amaranthus tubercula/us) and wild mustard (Sinapis arvensisf,

HISTORY OF BEAD ASSESSMENTS FOR CHEMICAL THIFENSULFURONMETHYL

A search of BEAD's document data bases including BEAD's Offici al Records and the BEAD

Section 18 data base did not reveal any requests, assessments or reviews for the use of

thifensulfuron-methyl by che mical or product name (Harmony)

DATA NEEDS RELEVANT TO BEAD' S FUTURE WORK ON CHEMICAL

THIFENSULFURON-MET II YL

BEAD needs inform ation for the agricultural use ofthifensulfuron. Specifically, with regards to

the agronomic uses, what weeds thifensulfuron is used to control, what are the primary chemical

alternatives thifensulfuron is used to con trol and what target spec ies have demon strated

resistance. In add ition, economic data needs for future work include the following agronomic

information: growers cost ofthifensulfuron in terms cf cost per pound AI and the cost per acre

treatment, the cost of alternative controls in terms of the cost per pound AI and the cost per acre

treatment; the percent of the particular crop treated with thifensulfuron; production data for flax,

safflower, oats and triticale including production costs for each on a per acre basis.

REFERENCES

GfK Kynetec, 1998-2008 Proprietary data.

Heap, I. The International Survey of Herbi cide Resistant Weeds. 2010

4 Heap, I. The International Survey of Herbicide Resistant Weeds. Online. Internet. August 12, 2010 .

Available www.weedscience.com

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