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Polyoxin D Zinc Salt - Registration of Endorse WP Turf Fungicide 5/02

New York State Department of Environmental Conservation
Division of Solid and Hazardous Materials
Bureau of Pesticides Management, 9th Floor
625 Broadway, Albany, New York 12233-7254
Phone: (518) 402-8788     FAX: (518) 402-9024

May 16, 2002


Ms. Marissa N. Carlos
Technical Assistant
Arvesta Corporation
100 First Street, Suite 1700
San Francisco, California 94105

Dear Ms. Carlos:

Re: Application for Registration of Endorse WP Turf Fungicide (EPA Reg. No. 68173-2-66330)
Which Contains the New Active Ingredient Polyoxin D Zinc Salt

    The New York State Department of Environmental Conservation (Department) has reviewed the application, received September 12, 2001, from Arvesta Corporation, formerly Tomen Agro, Inc., to register the above-mentioned product in New York State. This product contains the new active ingredient polyoxin D zinc salt.

    The application was forwarded to the New York State Department of Health (DOH), to our geological staff, as well as the Bureau of Habitat (BOH), for review. The application was deemed complete for purposes of review on January 24, 2002 and a registration decision is due by June 21, 2002.

    Endorse WP contains 2.5% of the active ingredient, polyoxin D zinc salt and is a systemic, foliar applied turf fungicide for control of Brown Patch and Large Patch caused by Rhizoctonia. Endorse is applied at the rate of four ounces of product in a minimum of 0.5 gallons of water per 1,000 square feet (or 0.006 lb ai/1000 sq. ft.) at seven- to 14-day intervals with no maximum application rate stated. The inerts do not appear to be solvent carriers.

    The Department has reviewed the information submitted to date in support of the application for registration of Endorse WP (EPA Reg. No. 68173-2-66330).

    Polyoxin D is produced via a fermentation process using the soil bacteria Streptomyces cacaoi var. asoensis. This active ingredient interferes with fungal cell wall production by inhibiting the enzyme chitin synthetase. Polyoxin D zinc salt has been classified by the U.S. Environmental Protection Agency (USEPA) as a "biochemical-like" pesticide. Consequently, the USEPA required only limited toxicological data for federal registration of Endorse WP Turf Fungicide and waived the requirement for environmental fate data.

    The oral, dermal and inhalation acute toxicity data on Endorse WP Turf Fungicide and polyoxin D zinc salt indicate that neither was very toxic by these routes of exposure. Also, whereas the active ingredient caused slight to moderate eye irritation and was mildly irritating to the skin (tested on rabbits), the Endorse WP Turf product was not a skin irritant, and was only mildly irritating to the eyes. The formulated end-use product was not a skin sensitizer (tested on guinea pigs); the active ingredient was a mild skin sensitizer.

    No developmental toxicity effects in fetuses were reported when polyoxin D zinc salt was administered to pregnant rabbits during organogenesis at doses up to the highest level tested, 800 milligrams per kilogram body weight per day (mg/kg/day). Maternal toxicity, based on decreased mean body weight gain was reported at 200 mg/kg/day; the no-observed-effect level (NOEL) was 50 mg/kg/day.

    Although chronic toxicity/oncogenicity studies on polyoxin D zinc salt were not required for federal registration of this active ingredient, the USEPA briefly reported in its Registration Eligibility Document (August 1997), on the results of such registrant-sponsored studies. No chronic toxicity or oncogenic effects were reported either in rats or mice fed polyoxin D zinc salt at the highest doses tested, which for rats were 2,059 and 2,470 mg/kg/day (males and females, respectively) and for mice were 3,591 and 4,177 mg/kg/day (males and females, respectively). Polyoxin D zinc salt gave a weakly positive result in two genotoxicity studies. A search of the toxicological literature did not find any additional information on adverse effects from exposure to polyoxin D zinc salt.

    There are no chemical specific federal or State drinking water/groundwater standards for polyoxin D zinc salt. Because this chemical is a (zinc) salt of polyoxin D, the general New York State drinking water standards for "principal organic contaminants" and "unspecified organic contaminants" do not apply. However, the free acid polyoxin D in an aqueous environment would fall under the 50 microgram per liter general New York State drinking water standard for an "unspecified organic contaminant" (10 NYCRR Part 5, Public Water Systems).

    The available information indicates that the labeled uses of polyoxin D zinc salt should not pose significant risks to those who may use the product. Neither the active ingredient nor the formulated end-use product was very acutely toxic. In addition, the limited data on the toxicity of polyoxin D zinc salt from repeated exposures indicate that the potential for significant risks to public health is minimal.

    According to the Biopesticide Fact Sheet for Polyoxin D Zinc Salt (230000) dated 8/01, "Polyoxin D Zinc Salt is used as a fungicide for turf on golf courses, parks, home lawns and the grounds of commercial and institutional buildings. Given the lack of toxicity and limited use sites, this active ingredient is not expected to harm people, pets, wildlife, or the environment when used according to label directions."

    The Environmental Assessment Branch of the USEPA does not perform an environmental exposure assessment on biopesticides unless the Toxicology Branch has a problem with the information presented by the registrant. In this case, no problem was noted; therefore, environmental fate data were not required. Since environmental fate data were not necessary, there is no impact to the groundwater to be assessed.

    Polyoxin D is highly water soluble. It is formulated as the zinc salt to lower its solubility, to roughly 8590 ppm, allowing for longer residence time on plant surfaces.

    Polyoxin D zinc salt has very low toxicity to mammals and birds, and ranges from moderately toxic to highly toxic to the few aquatic animals for which data was required. A nontarget terrestrial arthropod, two insects and a mite, toxicity study was classified as supplemental by USEPA because it utilized Asian agricultural pests instead of beneficial insects required by U.S. guidelines. Topical applications of Polyoxin D zinc salt were not toxic to two-spotted spider mite, Tetranychus urticae, brown plant hopper, Nilaparvata lugens, or diamond back moth, Pulutella xylostella, eggs, nymphs, or larvae at concentrations up to 400 ppm which is slightly more than ten times the field application rate. Nontarget plant and honeybee toxicity studies were waived.

    Polyoxin D degrades rapidly in the environment. Correspondences with USEPA and study abstracts from the open literature were submitted that indicate a soil half life of two to three days. All environmental fate studies were waived by USEPA.

    Screening level avian and mammalian feeding exposure estimates and aquatic runoff modeling were conducted utilizing highly conservative assumptions. Under the exaggerated conditions, the only toxicity threshold exceeded was a NOEC concentration for Daphnia, the most sensitive test species, at the highest exposure calculated. Exposures under labeled field use are not expected to approach the levels modeled. Legal use of ENDORSE is unlikely to result in adverse effects to fish or wildlife resources.

    Based on the above-mentioned information, the Department accepts for general use registration in New York State Endorse WP Turf Fungicide (EPA Reg. No. 68173-2-66330) which contains the new active ingredient polyoxin D zinc salt.

    Enclosed is your Certificate of Registration and New York State stamped "ACCEPTED" label.

    If you have any questions, please contact Samuel Jackling, Chief of our Pesticide Product Registration Section, at (518) 402-8768.


Maureen P. Serafini
Director, Bureau of Pesticides Management
Division of Solid & Hazardous Materials

cc: w/enc. - N. Kim/D. Luttinger - NYS Dept. of Health
R. Zimmerman/R. Mungari - NYS Dept. of Ag. & Markets
G. Good/W. Smith - Cornell University, PMEP