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chlorfenapyr NYSDEC Letter of Registration Approval 1/02

New York State Department of Environmental Conservation
Division of Solid & Hazardous Materials
Bureau of Pesticides Management
Pesticide Product Registration Section
625 Broadway, Albany, New York 12233-7257
Phone 518-402-8768 FAX 518-402-9024

January 16, 2002


Ms. Michaeleen Linahan
BASF Corporation
P.O. Box 400
Princeton, NJ 08543-0400

Dear Ms. Linahan:

Re: Registration of PylonŽ Miticide-Insecticide (EPA Reg. No. 241-374) and the Manufacturing Use Product (MUP) Chlorfenapyr Technical (EPA Reg. No. 241-366) Containing the New Active Ingredient Chlorfenapyr.

The New York State Department of Environmental Conservation (Department) has completed its technical review of your application submitted in support of the registration of Pylon Miticide/Insecticide (EPA Reg. No. 241-374) and the manufacturing use product Chlorfenapyr Technical (EPA Reg. No. 241-366) containing the new active ingredient chlorfenapyr. The Department has registered these products for formulation and labeled use on ornamental crops in commercial greenhouses to control mites, caterpillars, fungus gnats, and thrips. The Department has registered the Pylon Miticide/Insecticide as a "Restricted Use" product due to concerns raised during the technical review for impacts to fish and avian resources.

The active ingredient, chlorfenapyr is a member of the family of compounds known as pyrroles. Pylon is ingested by target organisms and acts to disrupt mitochondrial action which produces energy in the organism. Pylon uncouples oxidative phosphorylation, preventing conversion of ADP to ATP. The mite or insect dies from the inability to generate energy.

Pylon Miticide/Insecticide is a liquid that is mixed with water and applied as a foliar spray to ornamental crops grown in commercial greenhouses. The product contains 21.4% by weight of the active ingredient chlorfenapyr. The maximum application rate to ornamentals is three applications not to exceed 41 ounces of product or 0.64 pounds of active ingredient per crop growing cycle. The label has a section on resistance management which discusses strategies for reducing the potential of developing pest resistance by alternating the use of this product with other miticides/insecticides with different modes of action. The Application was received by the Pesticide Product Registration Section (PPRS) on May 31, 2001 and was deemed incomplete for purposes of technical review on August 1, 2001. The application required two documents to complete the application package for the Department's environmental fate review. The missing information was submitted by the Applicant on August 14, 2001. The Application and additional data were reviewed and a completeness determination was issued on September 5, 2001. Pursuant to the review time frame specified in ECL §33-0704.2, a registration decision date of February 1, 2002 was established. The Department conducted the following technical reviews with regard to the registration of Pylon Miticide/Insecticide and Chlorfenapyr Technical, for impacts to human health, non-target organisms, and the environment. Review summaries are provided below.

Human Health Summary:

Neither the manufacturing use product, Chlorfenapyr Technical nor Pylon Miticide-Insecticide, was very toxic following acute exposure in laboratory animals. Chlorfenapyr also did not cause developmental or reproductive effects after ingestion by pregnant rats and rabbits. Although chlorfenapyr caused some effects following chronic exposure and there was suggestive evidence that this chemical may have carcinogenic potential, the expected low exposure from the labeled use of Chlorfenapyr Technical and Pylon Miticide-Insecticide should not pose a significant risk to workers or the general public. In addition, because of the very low vapor pressure of chlorfenapyr (less than 1.0 x 10-7 millimeters mercury at 25 degrees Celsius), the potential for inhalation exposure to this chemical following its application appears minimal. In addition, the Pylon product does not contain solvents that pose a concern for confined space use such as in greenhouses.

Non-target Organism Summary:

Technical chlorfenapyr has a water solubility of 0.14 mg/L at pH 7. It has a low vapor pressure, 1.0X10-7 mmHg, thus volatilization will not contribute significantly to dissipation. Its octanol/water partition coefficient, KOW, is 67,670 at 25O C. A Bluegill sunfish accumulation study yielded bioconcentration factors for edible and non-edible tissues of 830x and 3400x respectively. Its depuration half-life, T1/2, was approximately 4 days. Roughly 97% of the accumulated residues had depurated within 21 days of exposure cessation.

Chlorfenapyr is slightly to highly toxic to mammals. It is highly to very highly toxic to birds, and is very highly toxic to all aquatic organisms for which data was submitted. The January 10, 1997 United States Environmental Protection Agency (USEPA) Environmental Fate and Effects Review of chlorfenapyr use on cotton states that chlorfenapyr is one of the most chronically toxic pesticides to avian species that they had evaluated to date.

Fish and wildlife exposures from the Pylon labeled greenhouse uses should be minimal to nonexistent. The label contains extensive warnings in the ENVIRONMENTAL HAZARDS section regarding contamination of surface waters which should prevent exposure via drainage. Properly contained use within a commercial greenhouse should not adversely affect fish and wildlife resources.

Environmental Fate Summary:

HYDROLYSIS: Chlorfenapyr is stable at pHs 5, 7 and 9.

AQUEOUS PHOTOLYSIS: Chlorfenapyr has half-lives of 5.1-5.4, 6.9-8.1 and 4.8-4.9 days in sterile aqueous solutions of pH 5, 7 and 9 respectively. One degradate was found, CL-357806, ranging from 55% to 73% of applied based on pH. However, aqueous photolysis is not a major degradation route because this is a foliar spray for greenhouse use.

SOIL PHOTOLYSIS: Chlorfenapyr has a half-live in a sandy loam soil of approximately 75 + 21 days (MRID 42770242). According to the 8/31/98 memorandum, the half-life is approximately 0.4 years (146 days).

AEROBIC SOIL METABOLISM: Chlorfenapyr has a half-life in sandy loam of 3.8 years (MRID42770243); however, USEPA felt this data was anomalous. In the 8/31/98 EFED memorandum, USEPA indicated that the half life is 1.4 years based on five soils (MRID 44452621-not presented with application).

AEROBIC AQUATIC METABOLISM: Chlorfenapyr has a half-life of 0.8 years in the aqueous portion and 1.1 years in the soil portion, according to the 8/31/98 EFED memorandum.

ANAEROBIC SOIL METABOLISM: Chlorfenapyr has an estimated half-life of 2 years according to the 8/31/98 EFED memorandum.

ADSORPTION/DESORPTION: This study was found to be upgradable and partially satisfied the data requirements; however, USEPA felt that despite the shortcomings of the study, chlorfenapyr was strongly bound to all test soils and would not be expected to be mobile. The Kocs for the parent are 13,214 in loamy sand, 14,117 in sandy loam, 12,321 in loam and 18,095 in silt loam. In the 8/31/98 memorandum, USEPA indicated that chlorfenapyr has a relatively high Koc of about 12,000 and as such, leaching would not be significant in soil dissipation studies.

The study for the degradate (in the same soils as the parent) was acceptable and found the Kocs for the degradate are 5,000 in loamy sand, 2,352 in sandy loam, 2,774 in loam and 2,095 in silt loam.

FIELD DISSIPATION: Five studies were done, and all were upgradable, and further information was needed. The studies did not investigate or attempt to identify degradates, so the routes of dissipation cannot be established. USEPA stated in the DER that "However, it is clear from these studies that parent pesticide AC303,630 is indeed persistent, as defined below, and does not leach." Minimum field dissipation half-lives were stated to be 0.4-0.6 years in loamy sand, 0.4-0.8 years in sandy loam, 0.6-0.9 years in silt loam, 0.6-1.4 years in clay loam, and 0.8-2.1 years in sand.

A May 6, 1997 letter to the USEPA presented data indicating that the registrant went back and did degradate work and found an average field dissipation half-life of the parent of 273 days (175-418 days). They indicated that CL 312,094 was found at a maximum of 30% and two minor (<10%) degradates, CL 303268 and CL 322118 were found. These degradates further degraded to form CL303267, CL325195 and CL322250. However, there is nothing in the application from USEPA indicating that they found this supplemental data acceptable.

In the 8/31/98 memorandum, USEPA indicated that two supplemental multi-year soil dissipation studies demonstrated the trend towards increasing concentrations over time. Soil concentrations ranged from 0.1 ppm in the first year to 0.3 and 0.4 ppm in the fourth year of the study.

In the 8/31/98 memorandum USEPA indicated that the half-life was 1.3 years based on five small-plot cotton studies in four cotton states (MRID 43492850).

Given the very long half-lives and the very high Kocs for chlorfenapyr, there is very little probability that this product, when used as directed in greenhouses, will cause any impact to groundwater. However, should the registrant apply for other than greenhouse uses in the future, the application should be carefully reviewed because this active ingredient is very persistent and accumulates in soil when used on a yearly basis.


The Department has determined that the Pylon Miticide/Insecticide product should be registered as "restricted use" based on the concerns raised in the non-target organism and environmental fate reviews. Use restrictions will limit the use of the Pylon product to only certified applicators or those working directly with a certified applicator. The "Restricted Use" status will provide a higher level of assurance that the product will be applied according to label directions. The label contains extensive warnings in the ENVIRONMENTAL HAZARDS section regarding toxicity to fish and wildlife as well as contamination to surface waters. The Department believes that properly contained use of the Pylon product should not adversely affect fish and wildlife resources. However, new applications containing this active ingredient, which demonstrate a labeled use outside the controlled environment of a commercial greenhouse, will be reviewed with a high degree of caution towards the protection of aquatic and avian resources.

Please note that the Pylon Miticide/Insecticide product, as noted on the "restriction" column on the Certificate, is to be classified as "restricted use" under rules and regulations 6NYCRR 326.2(g). As such, this product is restricted in its purchase, distribution, sale, use and possession in New York State.

According to New York State Department of Environmental Conservation Regulations 6NYCRR 326.3(a): "It shall be unlawful for any person to distribute, sell, offer for sale, purchase for the purpose of resale, or possess for the purpose of resale, any restricted pesticide unless said person shall have applied for, and been issued a commercial permit."

The Pesticide Reporting Law (PRL) requires all certified commercial pesticide applicators to report information annually to the Department regarding each pesticide application they make. Commercial pesticide retailers are required to report all sales of restricted pesticide products and sales of general use pesticide products to private applicators for use in agricultural crop production. If no sales are made within New York State, a report still must be filed with the Department indicating this is the case.

If you need information relating to the Pesticide Reporting Law, or annual report forms, please visit the Department's website at or call 1-888-457-0110 (toll free within New York State). Out-of-State callers may contact the Pesticide Reporting Section at (518) 402-8765.

Should you require information to obtain a commercial permit, please contact Thomas Lynch, Chief, Pesticide Certification Section, at (518) 402-8748.

Enclosed for your record is a copy of the stamped accepted label and the Certificate of Registration for Pylon Miticide/Insecticide (EPA Reg. No. 241-374) and Chlorfenapyr Technical (EPA Reg. No. 241-366). Please note that a proposal by BASF Corporation or any other registrant, to register a product that contains chlorfenapyr, and whose labeled uses are likely to increase the potential for significant impact to humans, non-target organisms, or the environment, would constitute a major change in labeled (MCL) use pattern. Such an application must be accompanied by a new application fee and meet the requirements listed in Appendix 1.B. of "New York State Pesticide Product Registration Procedures" (August 1996). Such information as well as forms can be accessed at our website as listed in our letterhead.

Please contact our Pesticide Product Registration Section, at (518) 402-8768 if you have any questions.


Maureen Serafini
Bureau of Pesticides Management

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