2

provided in the “Usage and Label Use Data Packages” that are also provided to Registration Review teams by BEAD. The document is based on information and data available to BEAD as of December 17, 2010.

Isoxaflutole is a postemergence herbicide used in corn to control broadleaf and grass weed species. This herbicide is a cyclopropylisoxazole chemical with the mechanism of action o f inhibiting the enzyme used in carotenoid synthesis. It is classified by the Herbicide Resistance Action Committee and Weed Science Society of America in group F2 27

. 1 Currently, there are no confirmed weed species or biotypes reported as resistant to this herbicide in the U.S.

USE SITES Isoxaflutole is registered for use on field corn.

COMMON FORMULATIONS AND APPLICATION METHODS Isoxaflutole may be formulated as water dispersible granules, emulsifiable concentrate, or as a

soluble concentrate.

The herbicide can be applied by ground boom and can be incorporated (shallow) into soil above the seed planting zone (no aerial application).

USAGE Based on private market survey data from 1998-2008, usage on corn averaged approximately 250,000 pounds for nearly 4.5 million acres (GfK Kynetec, 1998-2008). Isoxaflutole is typically applied once per year at a rate of approximately 0.06 pounds per acre (GfK Kynetec, 1998- 2008).

The states with the most agricultural usage in terms of pounds AI applied are: Iowa, Illinois, Nebraska, Indiana, South Dakota, and Ohio (Figure 1). The ranking was the same in terms of the

total area treated.

Figure 1. States with Highest Isoxaflutole Use- Pe rcent of Total Lbs A.I. Applied

Source: GfK Kynetec, 1998-2008

1 http://www.hracglobal.com/Publications/ClassificationofHerbicideModeofAction/tabid/222/Default.aspx Iowa

36%

Illinois

18% Nebraska

13% Indiana

11% South Dakota

6% Ohio

6% Other

10%3

USE TRENDS The historical usage data provided in this section is provided for preliminary scoping purposes only, to convey a broad overview of Isoxaflutole at the beginning of the registration review

process.

Source: GfK Kynetec, 1998-2008

BIOLOGICAL ASPECTS RELEVANT TO ISOXAFLUTOLE Currently, there are no confirmed weed species or biotypes reported as resistant to this herbicide in the U.S. In addition, this herbicide is often used to control weed species and biotypes that are resistant to other herbicides (e.g. glyphosate).

HISTORY OF BEAD ASSESSMENTS FOR ISOXAFLUTOLE There have been no Section 18 requests evaluated by BEAD for this chemical.

BEAD Environmental Chemistry Laboratory (ECL) reviewed the method (MRID No. 471716- 01) for detection of Isoxaflutole and its primary metabolite RPA 202248 in surface water and ground water submitted by Bayer CropScience in accordance with the registration of Isoxafluotole. ECL concluded that this method was acceptable with minor deficiencies (EPA 2008).

DATA NEEDS RELEVANT TO BEAD’S FUTURE WOR K ON ISOXAFLUTOLE Obtaining additional information on the following items would improve future BEAD assessments of the importance of Isoxaflutole and may be required as part of the registration review of this pesticide.

At this time BEAD has no data needs. 0 400,000

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008Pounds A.I. Applied

Year4

REFERENCES

GfK Kynetec. 1998-2008. EPA Proprietary Data

EPA/OPP/BEAD. Environmental Chemistry Laboratory. Isoxaflutole in Water Method Review Report No. ECM0236W1-W2. DP Barcode: 342502. 2008.