UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF           

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

  SEQ CHAPTER \h \r 1 MEMORANDUM

DATE:  	25-MAR-2009

SUBJECT:	Iodosulfuron-Methyl-Sodium in/on Wheat; Revised Response to the
Health Effects Division (HED) Review of 29-OCT-2008 (DP#: 350509).

PC Code:  122021	DP Barcode:  D363431

Decision No.:  388140	Registration No.:  264-IEN

Petition No.:  1F6299	Regulatory Action:  Section 3 Registration

Risk Assessment Type:  NA	Case No.:  NA

TXR No.:  NA	CAS No.:  144550-36-7

MRID Nos.:  47671201-47671202	40 CFR:  §180.580



FROM:	Sarah J. Levy, Chemist

Registration Action Branch 1 (RAB1)/HED (7509P)

THROUGH:	George F. Kramer, Ph.D., Senior Chemist

RAB1/HED (7509P)

TO:		Jim Tompkins/Hope Johnson, RM 25

Registration Division (RD) (7505P)

Executive Summary

This memorandum supersedes the previous HED document (Memo, S. Levy,
18-MAR-2009; DP#: 362191), which did not reflect all of the submitted
residue analytical method data from the registrant.

Bayer CropScience proposed a Section 3 registration for the 5%
water-dispersible granule (WDG) formulation of
iodosulfuron-methyl-sodium (Hussar® Herbicide; EPA File Symbol No.
264-IEN) for use on spring and winter wheat (including durum).  The
product is proposed for postemergence foliar application at a maximum
seasonal application rate of 0.009 lb ai/A, with proposed preharvest
intervals (PHIs) of 55 days for grain and straw.  

In conjunction with the requested use, Bayer CropScience submitted a
petition, PP#: 1F6299, for the establishment of permanent tolerances for
the residues of the herbicide iodosulfuron-methyl-sodium (methyl
4-iodo-2-[3-(4-methoxy-6-methyl-l,3,5-triazin-2-yl)ureidosulfonyl]benzoa
te, monosodium salt) in/on the following raw agricultural commodities
(RACs):

Wheat, grain	0.02 ppm

Wheat, forage	0.06 ppm

Wheat, hay	0.05 ppm

Wheat, straw	0.05 ppm

Iodosulfuron-methyl-sodium is a sulfonylurea herbicide intended to
control annual and perennial grass and broadleaf weeds.  In the U.S.,
iodosulfuron-methyl-sodium is registered for use on field corn and for
preplant burndown on soybeans, and it is formulated as 2% and 10% WDG
formulations.  A residential use is registered for
iodosulfuron-methyl-sodium on ornamental turfgrass.  All applications of
this product are to be performed by professional (commercial)
applicators only.

The current petitioner’s amendment addresses residue chemistry
deficiencies relating to PP#: 1F6299, identified in HED’s review of
29-OCT-2008 (Memo, S. Levy; DP#: 350509).

Regulatory Recommendations

A risk assessment was previously completed for PP#: 1F6299 (Memo, S.
Levy et al.; 12-NOV-2008; DP#: 350046).  All residue chemistry
deficiencies relating to PP#: 1F6299 are now resolved.

DETAILED CONSIDERATIONS

860.1200 Directions for Use

Deficiency - 860.1200 Directions for Use (from Memo, S. Levy,
29-OCT-2008; DP#: 350509)

A revised Section B should be submitted to reflect PHIs for wheat forage
and hay of 21 and 50 days, respectively.

Petitioner's Response:  The petitioner submitted a revised Section B.

HED's Conclusion:  HED has received a revised Section B (accepted
11-FEB-2009) which reflects PHIs for wheat forage and hay of 21 and 50
days, respectively.  This deficiency is now resolved.

860.1340 Residue Analytical Methods

Deficiency - 860.1340 Residue Analytical Method - Plant Commodities
(from Memo, S. Levy, 29-OCT-2008; DP#: 350509)

The petitioner should submit additional validation data for the proposed
enforcement method from samples of wheat forage and hay or straw
fortified at the stated limit of quantitation (LOQ) for these
commodities, 0.05 ppm.  In addition, the petitioner should modify Method
BY/02/99 to incorporate the changes recommended by the ILV laboratory.

Petitioner's Response:  The petitioner noted that Method BY/02/99 has
been proposed as the tolerance enforcement method for all crops.  This
method has been adequately validated with corn grain, forage, and
stover.  This method has also been successfully independently validated.
 According to GLN 860.1340, the method only needs to include recovery
data from a representative number of crops, in this case corn.  Corn
matrices are very similar in nature to the wheat matrices and provide an
excellent level of confidence that the method is suitable for both corn
and wheat (and other cereal crops).

The petitioner stated that Method BY/02/99 has been revised to include
the recommendations from the ILV and has been renamed BY/02/99, Revision
1.  The revised method will be provided to the Agency as a separate
document.

HED's Conclusion:  The petitioner adequately demonstrated that the
existing data support the conclusion that method BY/02/99 is a suitable
enforcement method for all cereal crops, including wheat and that no
additional data are necessary.  HED has received an acceptable revised
method (BY/02/99, Revision 1).  The deficiencies relating to residue
analytical methods are now resolved.  The method will now be forwarded
to the U.S. Food and Drug Administration (FDA) for publication in the
Pesticide Analytical Manual (PAM) Volume II.  

860.1550 Proposed Tolerances

Deficiency - 860.1550 Proposed Tolerances (from Memo, S. Levy,
29-OCT-2008; DP#: 350509)

The petitioner should propose an increased tolerance of 0.10 ppm for
wheat forage.

Petitioner's Response:  The petitioner submitted a revised Section F.

HED's Conclusion:  HED has received a revised Section F with the
recommended tolerance level of 0.10 ppm for wheat, forage.  This
deficiency is now resolved.

References

Memo, S. Levy, 29-OCT-2008; DP#: 350509

Memo, S. Levy et al.; 12-NOV-2008; DP#: 350046

Memo, S. Levy, 18-MAR-2009; DP#: 362191

cc:  S. Levy (RAB1/HED)

RDI:  G.F. Kramer (03/25/09)

S. Levy:S10953:PY-S:(703)305-0783:7509P:RAB1

Template Version November 2003

Iodosulfuron-methyl-sodium	Response to Previous HED Review	DP#: 363431 

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