UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C ., 20460

MEMORANDUM

NOV 2 9 20 10 OfFICE OF CHEMICAL SAFETY

AND POLLunoH PREVEN110N

SUBJ ECT:

FROM:

THRU:

BEAD Chemical Profile for Registration Review: Cloransulam-methyl (129 116)

Sunil Ratnayake , Biologist /I. L , I ,

Biological Analysis Branc h "'. \ j\

Sepehr Haddad, Environmental Scientist If4) 1.1/, J

Science Information and Analysis Branch VI- I~

Andrew Lee, Economist ~Z C. J

Economic Analysis Branch l/f/""

Biological and Economic Analysis Division ( 03P)

Arnet Jones, Chief jp;1<"+- Biological Analysis Branch (.J?<--

Diann Sims, Chief

Science Information and Analy sis Branch

Timothy Kiely, Chief {,).... [;I,\.

Economic Analysis Branch 'J J

Biological and Economic Analysis Division (7 P)

TO: Carissa Cyran Chemical Review Manager

Pesticide Reeva luation Division (7508P)

Peer Review Panel Date: May 19,2010

INTRO DUCTION

Cloransulam-methyl belongs to sulfonanillide herbicide group and it inhibits the enzym e

acetolactate synthetase (ALS). Cloransulam-methyl was first registered in 1997 by DowElanco

and it is labeled for broadleafweed control in soybeans. It controls broadleafweed species such

as giant ragweed (Ambrosia Irifida), common ragweed (Ambrosia anemisiifolia), horseweed

(Conyza Canadensis), sicklepod (Cassia obtusifolia}, cocklebur (Xanlhium strumarium), velvet

leaf(Abulilon theophrastiv wild mustard (Brassica /caber) and jimsonweed Datura stramonium

species. This herbicide is applied as pre-plant incorporated, pre-plant surface, pre-emergence
and post-emergence applications. Mode of action ofthis herbicide is inhibition ofthe

acetolactate synthase (ALS) enzyme.

PRI MARY USE SITES

This chemical is only used on soybeans.

COMMON FORMULATIONS AND APPLICATION METHODS'

Formulations include: dry flowable (water dispersible granules), wettable powder, and soluble

concentrate (solid).

This chemical is applied as ground spray, broadcast, bumdown treatment, soil treatment (surface,

incorporated, broadcast), and band treatment.

USAGE/USE TRENDS

Cloransularn Agricultural Usage

Based on private market pesticide usage data from 1998-2008, the annua l total agricultural usage

averaged approximately 44,000 pounds active ingredient for 2.5 million acres (GfK Kynetec,

1998-2008). During the 11 year time period, all use in terms oftotal pounds of active ingredient

applied was on soybeans (GfK Kynetec, 1998-2008). Cloransulam is not used on nonagricultural sites.

Figure I provides usage in terms of pounds applied annually from 1998-2008, for chloransulam's

only agricultural market, which is soybeans.

Figure 2 below shows average usage by state during the 11 year time period for states with the

most agricultural usage in terms of pounds active ingredient (A.I.) applied. These are : Iowa,

Illinois, Ohio, Indiana, Minnesota, Nebraska, and Missouri. (GfK Kynetec, 1998-2008).

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FIGURE 1. Cloransulam Usa e Pounds AI

0, OOO -r~~~-----------------------

Pounds AI

o

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

Source: GfK Kynetec, 1998-2008

FIGURE 2. AVERAGE USAGE BY STATE 1998-2008

7%

g lQWA

• ILLINOIS

DOHIO

D INOIANA

. MINNESOT

t1 NEBRASKA

• MISSOURI

15%

Source: GfK Kynetec, 1998-2008

PREVIOUS BEAD ASSESSMENTS

There are no previous BEAD assessments on this chemical includ ing Section 18s, benefit or

alternative assessments which had a role in risk-benefit decisions such as cancellations or

retention ofregistered uses, reduction in rates, and shorter REIs.

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OTHER ISSUES SUCH AS RESISTANCE, PLANT OR PUBLIC HEALTH CLAIMS

The mode of action of this herbicide is inhibition of the enzyme acetolactase synthase (ALS).

The introduction of sulfonylureas in 19805 was followed by other ALS inhibitors such as

imidazolinones, and triazolopyrimidine sulfonamides (Patzoldt et al, 200 1). ALS inhibitors were

widely used in crop production. Low rates, low mammalian toxicity, flexible application timing,

and broad spec trum of weed control were th e advantages of usin g these herbicides. However,

wide use of ALS inhibitors contributed to the development ofresistance bio-types to these

herbicides. Resistant weed species include: common ragweeds Ambrosia artemisiifolia, giant

ragweeds (A mbrosia trifida), prickly lettuce (lectuca serriola), kochia (Kochia scoparia), smooth

pigweed (Amaranthus hybridus), Livid amaranth (Amaranthus lividus} Red stem (Ammania

auriculate) downy brome (Bramus teetarum), and lambsquarters (Chenopodium album)

(International Survey of Herbicide Resistant Weeds, 2010).

BEAD SPECIFIC REGISTRAnON REVIEW ISSUES - BEAD DATA GAPS FOR

FUTURE ASSESSMENTS AND BEAD WORKPLAN

REFERENCES

GfK Kynetec (1998-2008) proprietary data.

FirstRate. 2010. Specimen Label. DowAgroSciences LLC.

International Survey of Herbicide Resistant Weeds. 2010. http://www.weedscience.org/ln.asp

Patzoldt, W. L., Tranel, P. J., Alexander, P L., and P. R. Schmitzer. 2001. A common ragweed

population resistant to cloransulam-methyl. Weed Sci. Vo1.49, No.4, pp. 485-490.

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