cyfluthrin (Baythroid) Registration of Additional Uses 8/96
New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
Bureau of Pesticides & Radiation
Pesticide Product Registration Section
50 Wolf Road, Albany, New York 12233-7257
Phone 518-457-7446 FAX 518-485-8990
August 2, 1996
Ms. Cynthia J. Whitten
Bayer Agriculture Division
8400 Hawthorne Road, P.O. Box 4913
Kansas City, MO 64120-0013
Dear Ms. Whitten:
Re: Registration of Additional Uses for Baythroid 2 Emulsifiable Pyrethroid
Insecticide (EPA Reg. No. 3125-351) - Use on Sweet Corn, Alfalfa,
This Department has reviewed and accepted for registration amended
labeling for the referenced pesticide product in New York State. The product
contains the active ingredient cyfluthrin.
Baythroid 2 (cyfluthrin) was registered in New York State on March 28,
1996 for use on cotton, carrots, peppers, radishes and tomatoes. This amended
registration allows use of Baythroid 2 to control insect pests on sweet corn,
alfalfa and sunflowers in New York State. The only differences between the
amended labeling for use on corn, alfalfa, and sunflowers and the previously
registered label for use on cotton, carrots, peppers, radishes, and tomatoes
are that when used on corn, alfalfa, and sunflowers 1) Baythroid 2 may be
applied by air; and 2) a maximum of ten applications are allowed instead of
We have determined that use of Baythroid 2 on the above mentioned field
crops should not result in significant adverse impacts to human health or the
environment in New York State.
Baythroid 2 is a federally "restricted use" pesticide due to fish and
aquatic organism toxicity. However, the Baythroid 2 label for use on corn,
alfalfa, and sunflower requires a 150-400 foot buffer strip when applied by
aerial spray, or a 25 foot buffer strip when applied by ground spray. This
should be adequate to protect water from spray drift.
To assess the impact of the ten applications allowed on sweet corn,
alfalfa, and sunflower instead of the six allowed for other crops, we modeled
the concentration of cyfluthrin on the ground following ten applications using
the following variables: half-life on soil - 8.7 days, ten applications, seven
day separation between applications. The highest concentration on the ground
resulting from 10 applications would be 0.115 lbs. of cyfluthrin per acre.
This is only slightly higher than the highest concentration that would occur
as a result of six applications (0.102 lbs. cyfluthrin per acre).
When modeled, the concentration of cyfluthrin on the ground from 10
application had about the same potential to harm aquatic systems as the
concentration on the ground resulting from six applications. Runoff results
were compared to the mesocosm study previously submitted by Bayer to support
the registration of Baythroid 2 on carrots, peppers, radishes, and tomatoes.
Some species of invertebrates may be temporarily impacted; however, the
mesocosm study showed that at the concentrations likely to occur from runoff
of treated fields, the overall abundance and diversity of aquatic life is not
likely to be impacted.
As noted in our data completeness letter to Sayer Corporation dated May
14, 1996, we requested clarification of the United States Environmental
Protection Agency's (USEPA) review which initially estimated that the maximum
daily exposure of non-nursing infants from all existing and proposed
tolerances could exceed the reference dose. In a letter to this Department
dated May 24, 1996, Bayer Corporation stated that the USEPA had agreed that
some of the calculations used in their dietary analysis were in error and
granted registration of the additional uses. We did not receive from Bayer any
correspondence from the USEPA documenting this acknowledgment, but the March
15, 1996 Federal Register (61:10678-81) contains a revised dietary exposure
analysis for cyfluthrin in all labeled crops. This analysis estimates
exposures for the general U.S. population and the most highly exposed subgroup
(non-nursing infants less that One year old) to be 0.004 mg/kg/day and 0.011
mg/kg/day, respectively. These values are 15 and 43.4 percent of the reference
dose for cyfluthrin respectively.
The New York State stamped accepted supplemental labeling Baythroid 2
Emulsifiable Pyrethroid Insecticide approving use on sweet corn, alfalfa and
sunflowers is enclosed for your records. Also enclosed is the stamped accepted
supplemental label Baythroid 2 to control several insects in sorghum.
If you have any questions, please contact Teresa Foster of my staff at
Maureen P. Serafini
Pesticide Product Registration Section
cc: w/enc. - W. Smith, Cornell University PMEP
N. Rudgers, Dept. of Ag & Mkts.
N. Kim/T. Grey, NYS Dept. of Health