PMEP Home Page --> Pesticide Active Ingredient Information --> Insecticides and Miticides --> cadusafos (Rugby) to cyromazine (Larvadex) --> cyfluthrin (Baythroid) --> cyfluthrin (Baythroid) Registration of Additional Uses 8/96

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
Licensing Clerk
Registrations Section
Bayer Agriculture Division
Bayer Corporation
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 
(518) 457-7446.


                                       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