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Fludioxonil - New Product Registration and Registration Application Withdrawal 2/03

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
Website: www.dec.state.ny.us

February 4, 2003

CERTIFIED MAIL
RETURN RECEIPT REQUESTED


John D. Abbott, Ph.D.
State Regulatory Affairs Team Leader
Syngenta Crop Protection, Inc.
P.O. Box 18300
Greensboro, North Carolina 27419-8300

Dear Dr. Abbott:

Re: Registration of the New Product Switch 62.5WG Fungicide (EPA Reg. No. 100-953) and Withdrawal of the Application for Registration of the Revised Label for Medallion Fungicide (EPA Reg. No. 100-769) Which Represent Major Changes in Labeling for the Active Ingredient Fludioxonil

    The New York State Department of Environmental Conservation (Department) has reviewed your applications, received June 6, 2002, and additional information received December 23, 2002, to register a revised label for Medallion Fungicide (EPA Reg. No. 100-769) and the new product Switch 62.5WG Fungicide (EPA Reg. No. 100-953) in New York State. The products represent major changes in labeling for the active ingredient fludioxonil (chemical code 071503).

    The applications were deemed complete for purposes of review on July 29, 2002 and a registration decision, originally due by December 26, 2002, has been waived by the registrant.

    Medallion Fungicide (EPA Reg. No. 100-769) (50% fludioxonil) is labeled for control of certain foliar, stem, and root diseases in turfgrass including golf courses, institutional, commercial and residential lawns, sod farms, sports fields, parks, municipal grounds and cemeteries, and of ornamental plants grown in interiorscapes, field nursery plantings, forest nurseries, residential and commercial landscapes, greenhouses, lath and shade houses, containers, and other enclosed structures. The revised Medallion Fungicide is labeled "For Professional Use Only." The maximum application rate for turfgrass, and field grown and landscape ornamentals is two pounds of fludioxonil per acre per year.

    Switch 62.5WG Fungicide (EPA Reg. No. 100-953) (37.5% cyprodinil + 25% fludioxonil) is labeled as a foliar treatment for control of certain diseases in onions and strawberries. The maximum application rate is 3.5 pounds of product per acre per year (1.3 pounds of cyprodinil and 0.88 pounds of fludioxonil per acre per year).

    Fludioxonil is currently registered in New York State for use on ornamental plants grown in containers, greenhouses and other enclosed structures, and as a seed treatment to control diseases in agricultural crops. The addition of "outdoor" ornamental and turf to the Medallion label, and the foliar application to agricultural crops on the Switch label represent major changes in labeling for the active ingredient fludioxonil.

    The Department has reviewed the information supplied to date in support of registration of the revised label for Medallion Fungicide (EPA Reg. No. 100-769) and the new product Switch 62.5WG Fungicide (EPA Reg. No. 100-953).

HEALTH EFFECTS:

Medallion

    The New York State Department of Health (DOH) stated that neither fludioxonil nor the formulated Medallion Fungicide product was very toxic in acute oral, dermal or inhalation toxicity studies in laboratory animals. Fludioxonil was minimally irritating to eyes, but not irritating to skin, whereas Medallion Fungicide was minimally irritating to both skin and eyes (tested on rabbits). Neither the active ingredient nor the formulated product was a skin sensitizer (tested on guinea pigs).

    Fludioxonil caused some toxicity in subchronic studies in laboratory animals. In a 90-day dog feeding study, fludioxonil caused diarrhea at 50 mg/kg/day; the NOEL was 5 mg/kg/day. An increased incidence of microscopic pathology of the kidney and liver and decreased body weight gain were seen in a 90-day rat feeding study at a dose level of 428 mg/kg/day in males and 462 mg/kg/day in females; the NOELs were 64 mg/kg/day and 70 mg/kg/day, respectively. Fludioxonil caused decreased body weight gain in females and changes in serum chemistry, increased liver to body weight ratio, and an increase in the incidence of nephropathy and centrilobular hypertrophy of the liver in both sexes in a 90-day mouse feeding study at a dose level of 1,052 mg/kg/day in males and 1,307 mg/kg/day in females; the respective NOELs were 445 mg/kg/day and 559 mg/kg/day.

    Fludioxonil also caused some toxicity in chronic animal feeding studies. In a one-year dog feeding study, fludioxonil caused decreased body weight, hematological alterations (increased platelets and fibrin), clinical chemistry alterations (increased cholesterol and alkaline phosphatase), and an increase in relative liver weights in males at a dose level of 298 mg/kg/day; the NOEL was 33 mg/kg/day. A marked decrease in body weight gain and an increase in relative liver weights were seen in females at a dose level of 35 mg/kg/day; the NOEL was 3.3 mg/kg/day. In a chronic feeding/oncogenicity study in mice, an increase in the incidence of clinical toxicity (increased incidence of mice convulsing when handled) was reported in male mice at a dose level of 112 mg/kg/day; the NOEL was 11 mg/kg/day. An increase in liver weight and macroscopic pathology was reported at 417 mg/kg/day in female mice; the NOEL was 133 mg/kg/day. In a chronic feeding/oncogenicity study in rats, fludioxonil caused decreased body weight and body-weight gain, an increase in the incidence and severity of histopathology changes in the liver of both sexes, and slight anemia in females at 12 months of exposure at dose levels of 113 mg/kg/day in males and 141 mg/kg/day in females; the NOELs were 37 mg/kg/day (males) and 44 mg/kg/day (females). The United States Environmental Protection Agency (USEPA) Office of Pesticide Programs established a reference dose (RfD) of 0.03 mg/kg/day for fludioxonil based on a NOEL of 3.3 mg/kg/day in a one-year dog feeding study and an uncertainty factor of 100 (species extrapolation and human variability). This RfD has not yet been adopted by the USEPA's Integrated Risk Information System (IRIS).

    Fludioxonil caused an increase in liver tumors in female rats that was statistically significant for combined adenoma/carcinoma only, but did not cause a tumorigenic response in male rats or in mice of either sex. Fludioxonil was negative in a number of genotoxicity studies. Based on these observations, the USEPA denoted fludioxonil as a Group D carcinogen-"not classifiable"-as to human carcinogenicity.

    Fludioxonil also caused some developmental effects in offspring of pregnant rats, but not rabbits, administered this compound during organogenesis at doses that also caused maternal toxicity. In the rat study, increased fetal and litter incidence of dilated renal pelvis and dilated ureter were reported at 1,000 mg/kg/day mg/kg/day; the NOEL was 100 mg/kg/day. The only reported endpoint of maternal toxicity was decreased body weight gain at a dose level of 1,000 mg/kg/day; the NOEL was 100 mg/kg/day. In the rabbit study, fludioxonil did not cause developmental effects at doses up to 300 mg/kg/day, the highest dose tested. Maternal toxicity was characterized by decreased body weight gain and food efficiency at 100 mg/kg/day; the NOEL was 10 mg/kg/day. In a two-generation reproduction study in rats, toxicity to offspring consisted of reduced pup body weights at dose levels of 221 mg/kg/day in males and 250 mg/kg/day in females; the NOELs were 22 mg/kg/day and 24 mg/kg/day, respectively. Parental toxicity to fludioxonil was reported as reductions in body weight, body weight gain and food consumption at dose levels of 221 mg/kg/day in males and 250 mg/kg/day in females; the NOELs were 22 mg/kg/day and 24 mg/kg/day, respectively.

    The USEPA reported the results of an occupational risk assessment for dermal and inhalation exposures to fludioxonil from application to greenhouse and nursery plants and turf grass. The assessment assumed that handlers wore a long-sleeved shirt, long pants, and gloves as per label requirements. For determining margins of exposure (MOEs), the USEPA compared estimated combined intermediate-term dermal and inhalation exposures to a NOEL of 64 mg/kg/day from the 90-day rat feeding study. The MOEs for various greenhouse, nursery, and turf grass application techniques (including handwand, groundboom, backpack, and drench) were estimated to be between 1,100 and 17,000. The post-application occupational exposures of most concern were considered to be cutting and sorting, sod harvesting, and transplanting to treated soil. The MOEs for these dermal exposures were estimated to be between 220 and 93,000,000. Generally, the USEPA considers MOEs of 100-fold or greater to provide adequate worker protection.

    There are no chemical specific federal or State drinking water/groundwater standards for fludioxonil or its major degradates. Based on their chemical structures, these chemicals fall under the 50 microgram per liter (_g/L) New York State drinking water standard for "unspecified organic contaminants" (10 NYCRR Part 5, Public Water Systems). The New York State drinking water standard for the sum of "unspecified organic contaminants" is 100 _g/L.

Switch

    The DOH stated that neither cyprodinil nor the formulated end product Switch 62.5 WG Fungicide was very toxic in acute oral, dermal or inhalation toxicity studies in laboratory animals. Cyprodinil was mildly irritating to eyes, but non-irritating to skin, whereas Switch 62.5 WG Fungicide was mildly to moderately irritating to eyes and slightly irritating to skin (tested on rabbits). The formulated end product was not a skin sensitizer, but the active ingredient was weakly to moderately sensitizing to guinea pigs.

    Cyprodinil caused some toxicity in subchronic dermal and feeding studies in laboratory animals. In a 28-day dermal toxicity study in rats, alterations in clinical signs (piloerection) occurred at dose levels of 1,000 milligrams per kilogram body weight per day (mg/kg/day) in males and 25 mg/kg/day in females; NOELs were 125 mg/kg/day and 5 mg/kg/day, respectively. In a 90-day dog feeding study, cyprodinil caused reduced body weight gains and food consumption at 560 mg/kg/day in males and 581 mg/kg/day in females; the respective NOELs were 210 mg/kg/day and 232 mg/kg/day. In a 90-day rat feeding study, increased tubular kidney lesions were seen in males at a dose level of 19 mg/kg/day; the NOEL was 3.1 mg/kg/day. Cyprodinil caused histopathological changes in the liver in a 90-day mouse feeding study at a dose level of 257 mg/kg/day in males and 349 mg/kg/day in females; the NOELs were 73 mg/kg/day and 103 mg/kg/day, respectively.

    Cyprodinil also caused toxicity in chronic animal feeding studies. In a one-year dog feeding study, cyprodinil caused decreases in body weight gains, food consumption and food efficiency at a dose level of 449 mg/kg/day in males and 446 mg/kg/day in females; the NOELs were 66 mg/kg/day and 68 mg/kg/day, respectively. In a chronic feeding/oncogenicity study in rats, cyprodinil caused degenerative liver lesions (spongiosis hepatis) in males at a dose level of 36 mg/kg/day; the NOEL was 2.7 mg/kg/day. In a chronic feeding/oncogenicity study in mice, a dose-related increase in the incidence of focal and multifocal hyperplasia of the exocrine pancreas was reported in male mice at a dose level of 212 mg/kg/day; the NOEL was 16 mg/kg/day. The USEPA Office of Pesticide Programs calculated a reference dose (RfD) of 0.03 mg/kg/day for cyprodinil based on a NOEL of 2.7 mg/kg/day from the rat chronic feeding/oncogenicity study and an uncertainty factor of 100 to account for inter- and intra-species extrapolation. This RfD has not yet been adopted by the USEPA's Integrated Risk Information System (IRIS).

    The USEPA classified cyprodinil as "not likely" to be a human carcinogen based on the lack of evidence of carcinogenicity in rats and mice. Cyprodinil also was negative in several genotoxicity studies.

    Cyprodinil showed some effects in developmental toxicity studies in rats and rabbits at doses that also caused effects in maternal animals. In the rat study, lower mean fetal weights and increases in the incidence of delayed ossification were reported at 1,000 mg/kg/day; the NOEL was 200 mg/kg/day. Maternal toxicity included reductions in body weight, body weight gain, and food consumption at a dose level of 1,000 mg/kg/day; the NOEL was 200 mg/kg/day. In the rabbit study, cyprodinil caused a slight increase in the number of litters showing extra (13th) ribs at a dose level of 400 mg/kg/day; the NOEL was 150 mg/kg/day. Maternal toxicity was characterized by decreased body weight gain at a dose level of 400 mg/kg/day; the NOEL was 150 mg/kg/day. In a two-generation reproduction study in rats, cyprodinil caused decreased pup weights at a dose level of 326 mg/kg/day; the NOEL was 81 mg/kg/day. Parental toxicity consisted of lower body weights in female rats during the pre-mating period at a dose level of 326 mg/kg/day; the NOEL was 81 mg/kg/day.

    The USEPA Office of Pesticide Programs established tolerances for the residues of fludioxonil in or on strawberries at 2.0 parts per million (ppm), dry bulb onions at 0.2 ppm, and green onions at 7.0 ppm. The USEPA estimated that chronic dietary exposure to these residues would be less than 3.7 percent of the chronic population adjusted dose (cPAD) of 0.03 mg/kg/day for the general United States population, less than 9.8 percent for children one to six years old, and less than 12 percent for all infants under one-year of age. The tolerances set for cyprodinil are 5.0 ppm on strawberries, 0.6 ppm on dry bulb onions, and 4.0 ppm on green onions. Chronic dietary exposure to these residues would be less than seven percent of the cPAD of 0.03 mg/kg/day for the general United States population, less than 22 percent for children one to six years old, and less than 23 percent for all infants under one-year of age. These chronic exposure analyses are based on the assumption that 100 percent of crops are treated and contain tolerance level residues. Actual residues and resulting exposure levels are expected to be less than these assessment estimates.

    The USEPA reported the results of an occupational risk assessment for dermal and inhalation exposures to cyprodinil and fludioxonil from application to onions. Onions were used in the assessment because they represent the largest average farm size of the labeled uses. For determining MOEs for cyprodinil, the USEPA compared estimated short- and intermediate-term dermal exposures to a NOEL of 25 mg/kg/day from the 28-day rat dermal toxicity study. The MOEs for commercial and private mixer/loader/applicators were estimated to range from 230 to 2,200. Inhalation exposure was not addressed by the USEPA in the assessment because of the use pattern of Switch 62.5 WG Fungicide, the low exposure potential, and the low acute inhalation toxicity. Inhalation exposure was considered for estimating the MOEs for fludioxonil (see below). The post-application occupational exposure of most concern for cyprodinil was hand harvesting of strawberries at day zero. The MOE for this exposure was estimated to be 74 using the intermediate-term dermal NOEL of 25 mg/kg/day from the 28-day rat dermal toxicity study. To reduce the extent of post-application exposure, a restricted entry interval (REI) of 12 hours was established. For determining MOEs for fludioxonil, the USEPA compared estimated combined intermediate-term dermal and inhalation exposures to a NOEL of 64 mg/kg/day from the 90-day rat feeding study. The MOEs for commercial and private mixer/loader/applicators were estimated to be between 2,100 and 19,000. Harvesting dry bulb onions was considered to be the post-application exposure of most concern for fludioxonil. The MOE for this exposure was estimated to be 1,900, again using the intermediate-term dermal NOEL of 64 mg/kg/day from the 90-day rat feeding study.

    There are no chemical specific federal or State drinking water/groundwater standards for cyprodinil or its degradates. Based on their chemical structures, they fall under the 50 microgram per liter (_g/L) New York State drinking water standard for "unspecified organic contaminants" (10 NYCRR Part 5, Public Water Systems). The New York State drinking water standard for the sum of "unspecified organic contaminants" is 100 _g/L.

Summary

    While neither fludioxonil nor cyprodinil was very acutely toxic, both compounds caused some subchronic, chronic, and developmental effects in animal studies. Fludioxonil also caused some limited increase in liver tumors in female rats, but was negative in male rats, mice and in numerous genotoxicity studies. Based on these data, the USEPA denoted this chemical as a Group D carcinogen- "not classifiable." The information in the registration package, however, indicates that the labeled use of the Medallion and Switch products should not pose significant risks to workers or the general public. Given the above, the DOH does not object to registration of the Medallion Fungicide or the Switch 62.5 WG Fungicide products.

ECOLOGICAL EFFECTS:

    The Department's Division of Fish, Wildlife & Marine Resources' Bureau of Habitat (BOH) reviewed the information submitted in support of registration of Medallion Fungicide (50% fludioxonil) and Switch 62.5WG Fungicide (37.5% cyprodinil + 25% fludioxonil). The BOH stated that fludioxonil is practically non-toxic to birds and mammals on an acute basis though it may be toxic with chronic exposures. It is highly toxic to all freshwater and marine organisms for which toxicity data was submitted. It is also toxic to aquatic plants.

    Fludioxonil is stable to hydrolysis. It is relatively labile to photodegradation in laboratory studies with soil surface and aqueous photolysis half-lives, T1/2s, of 1.6 and 8.7 days respectively, but appears not to photodegrade appreciably in the field. Microbial degradation is slow with aerobic soil metabolism T1/2s ranging from 143 to 220 days. No anaerobic studies are reported. Results from partially acceptable terrestrial field dissipation studies conducted in Georgia and New Jersey yielded T1/2s that range from 95 to 440 days with a mean in turf of 204 days. Formation and decline of degradates was not well characterized in the field studies.

    Four photodegradation products were identified in laboratory studies. Two degradates, CGA339833 and CGA192155, were identified in grass samples in the two field dissipation studies for which DERs were submitted. The other two degradates are unstable and degrade so rapidly that their mobility could not be determined in laboratory soil mobility studies.

    Grass concentrations of the two degradates were low in both studies. CGA339833 was detected at a maximum of 1.2 ppm, CGA192155 was detected at a maximum of 0.82 ppm. The only toxicity data available for either degradate is a rat 90-day feeding study conducted with CGA339833 submitted to EPA as required by FIFRA section 6(a)(2). While no LOEL or NOEC dietary concentrations are reported there appear to be no detectable effects below 800 ppm which suggests CGA339833 is significantly less toxic to mammals than the parent compound. The report also states that the soil T1/2 for CGA339833 is nine to 16 days.

    Screening modeling was conducted to estimate terrestrial and aquatic non-target exposures resulting from Medallion turf applications. No avian or mammalian acute toxicity thresholds were exceeded in modeled feeding exposures. Direct application to surface waters at the single application rate exceeds the LC50 for only the most sensitive aquatic species tested the algae Selenastrum.

    The BOH stated that Medallion Fungicide is not likely to adversely impact fish or wildlife resources when used as labeled. There is some uncertainty with respect to the field production of degradation products and their fate, but there is also limited evidence that the degradates occur at low concentrations, are not as toxic as the parent compound, and do not appear as persistent as fludioxonil.

    Switch 62.5 WG Fungicide is labeled for control of Botrytis Leaf Blight and Purple Blotch in onions and Gray Mold in strawberries. Applications of 0.258 lb. to 0.328 lb. cyprodinil and 0.172 lb. to 0.219 lb. fludioxonil are made using water as the carrier at seven to ten day intervals. No more than 3.5 lbs. Switch, four or five applications depending on use rate, may be applied per acre in a year.

    Cyprodinil is a relatively persistent compound, it dissipates in soil primarily via aerobic microbial metabolism with a mean field dissipation half-life, T1/2, of 69 days. In water its aerobic metabolism is slower but it is susceptible to photolysis. Cyprodinil has low toxicity to birds and mammals, is moderately toxic to fish, but is very highly toxic to aquatic invertebrates. Cyprodinil has slight to low soil mobility.

    Screening modeling to estimate terrestrial and aquatic non-target organism exposures resulting from labeled use of Switch showed no acute or chronic avian, or acute mammalian feeding toxicity thresholds were exceeded. The BOH stated that the use of Switch 62.5 WG Fungicide as labeled is unlikely to result in significant adverse impacts to fish or wildlife resources.

ENVIRONMENTAL FATE AND GROUNDWATER IMPACTS:

    The Department's groundwater staff stated the following:

CYPRODINIL:

Hydrolysis: Cyprodinil is stable at pHs 5, 7, and 9 after 32 days. Hydrolysis is not a significant route of degradation.

Solubility: Cyprodinil is soluble in water at a level of 13 mg/L at pH 7.0.

Aqueous Photolysis: Aqueous photolysis was found to be biphasic, with phototransformation of the parent in irradiated samples very slow during the first nine days, then faster from days nine to 30. A half-life of 22 days was extrapolated from the data curve. Canada did not consider aqueous photolysis a major route of dissipation.

Soil Photolysis: The half-lives from the radiolabeled studies were 64 to 70 days. Canada did not consider soil photolysis a major route of dissipation.

Aerobic Soil Metabolism: For the parent, there was confusing data. One European study showed that cyprodinil had a biphasic half-life, with rapid degradation during the first 28 days, then slowing for the rest of the study. The half-life for the first 28 days was calculated to be 30.8 days. For the slower phase, the calculated half-life ranged from 59-364 days. A second European study indicated a biphasic half-life, with the half-life for the first 21 days calculated to be 22.1 days; for the slower phase, the calculated half-life ranged from 28-363 days. A third and fourth study were performed on Collamer loamy sand, and results indicated a half-life of 39-46 days after 180 days. A fifth study was performed on Hanford sandy loam and indicated a somewhat biphasic pattern with calculated half-lives of 267 and 365 days. No pattern was discernible when the data was plotted. The half-lives calculated from the first 30 days of the study were 31 days and 22 days. Canada's summary states that the pattern of degradation is not clear; there is evidence to support both first order and biphasic degradation curves. For modeling, Canada chose a half-life similar to half-lives based on other laboratory and field data (69 days). Aerobic metabolism appears to be a major route of dissipation.

Adsorption/Desorption: Cyprodinil showed a high affinity for sorption to soil particles in batch equilibrium studies with four soils. Adsorption was positively correlated with organic content of the soil. The Kocs for sandy loam, sand, clay loam and loam were 2030, 1770, 1550 and 1630, respectively.

Degradate Adsorption/Desorption: The minor degradate CGA-249287 was shown to be highly mobile in a loamy sand with a Koc of 180, and moderately mobile in clay loam, loam, sandy loam and sand soils with Kocs of 173, 260, 650 and 867, respectively.

Degradate Adsorption/Desorption: The major degradate CGA-275535 was found to be immobile in six soils from the United States, with Kocs ranging from 1810 to 7500.

Degradate Adsorption/Desorption: The minor degradate CGA-321915 was found to be highly to moderately mobile in five soils from the United States, with Kocs for loamy sand, clay loam, loam, sand and sandy loam soils of 147, 50, 75, and 313, respectively.

Aged Leaching: In the two aged leaching studies, the bulk of the applied radioactivity remained in the top zero to two cm, with small amounts recovered throughout the column and approximately 1% recovered in the leachate from the two columns. Cyprodinil did not appear to leach in the column leaching studies.

Terrestrial Field Dissipation: In a California study, 3.0 lbs. ai/acre was applied to bare ground. The first order half-life for cyprodinil was 42 days with multiple applications, and 47 days from a single application. Two minor degradates, CGA-249287 and CGA-321915, were tracked along with the parent. CGA-249287 was detected soon after application to a maximum of 0.03 ppm, and decreased to below detection by 540 DAT (days after treatment). CGA-321915 was detected at levels of 0.011 to 0.016 between 60 and 240 DAT. Cyprodinil and CGA-249287 were not found below six inches. CGA- 321915 was found at 6-12 inches on 240 DAT and 360 DAT. Degradate CGA-275525 was not tracked.

In Columbia County, New York at a site representative of the geographic and climatic region for pome fruit and vegetable production, 3.0 lbs. ai/acre was applied to bare ground in multiple applications at seven day intervals, and at one application. The soil was loam down to 24 inches, and silt loam from 24 to 48 inches. The observed half-life was 14-28 days based on 0-540 DAT. CGA-279287 was found in the top six inches soon after application to a maximum of 0.086 ppm. It decreased to 0.028 to 0.048 ppm by 540 DAT. Cyprodinil was detected at random intervals at 0.011 to 0.050 ppm in the 6-12 inch samples. The plot was irrigated to 130% of the 30 year average for apple orchards. CGA-321915 was not detected in this study. CGA-249287 was found in the top six inches (loam). Degradate CGA-275535 was not tracked.

There were no detections of any compound below 12 inches in either study.


FLUDIOXONIL:

Hydrolysis: Fludioxonil is stable to hydrolysis at pHs 5, 7, and 9.

Aqueous Photolysis: This study, along with additional information provided, was found to be acceptable by the USEPA. The study indicated a half-life of 8.7 to ten days. Many minor degradates and two major degradates, CGA-339833 and CGA-344623, were formed. Degradate CGA-339833 was found at 31% and 15.1%, and degradate CGA-344623 was found at 4% and 11.3%.

Soil Photolysis: The USEPA found this study acceptable. Fludioxonil degraded fairly rapidly with a calculated half-life of 1.0 days to 1.6 days. Major degradates were CGA-265378 at 12.3%, and CGA-192155 at 10% and 11.7%.

Aerobic Soil Metabolism: The USEPA found this study acceptable. Fludioxonil has a half-life ranging from 143 to 220 days, suggesting that fludioxonil is fairly persistent under most conditions. No major degradates were detected.

Adsorption/Desorption: The USEPA found this study scientifically valid and that it partially fulfilled the USEPA requirements. Fludioxonil has a Koc in sand of 1490, in sandy loam of 2440, in Collamer loam of 991 and in Niagara loam of 1250.

Degradate Adsorption/Desorption: For degradate CGA-265378, the USEPA found the study not acceptable due to the instability of the test compound. No mobility could be determined.

Degradate Adsorption/Desorption: For degradate CGA-339833, the USEPA found the study acceptable. The study indicated virtually no sorption to sand, sandy loam, or two loam soils.

Degradate Adsorption/Desorption: For degradate CGA-308565, the USEPA found the study not acceptable due to the instability of the test compound. No mobility could be determined.

Degradate Adsorption/Desorption: The USEPA found this study scientifically valid and that it partially fulfilled the USEPA requirements. CGA-192155 was very mobile in sand, sandy loam and 2 loam soils with Kocs of 166, 15, 21 and 28, respectively.

Terrestrial Field Dissipation: The USEPA found this study (MRID 44382315) scientifically valid, but did not meet even the partial requirements because the analytical method and the storage stability data were inadequate. Half-lives were 228 days in a sand and 440 days in a loamy sand, as calculated by the registrant.

The USEPA found this study (MRID 44382316) scientifically valid, but did not meet even the partial requirements because the analytical method and the storage stability data were inadequate. Half-lives were 211 days in a silt loam and 95 days in a loam, as calculated by the registrant.

USEPA Comments: The uncertainties regarding the environmental risk of fludioxonil involve the fate, transport and toxicity of the major degradates of the compound. Preliminary data suggest that two (CGA-192155 and CGA-339833) of the three degradates are more mobile than the parent compound and may be more likely to either leach into ground water or runoff into surface waters.

Summary: Fludioxonil has an aerobic half-life between 143 and 220 days, but the Koc is fairly high so that it is not expected to impact groundwater when applied at the rate of either 0.88 lb. ai/a/yr, or 2.0 lbs. ai/a/yr. Degradate CGA-192155 is also mobile, and found at a maximum of 11.7% in soil photolysis laboratory studies. LEACHM modeling using the most conservative parameters predicted between 17 and 40 ppb, again depending on half-life and application rate. However, the model projected that this degradate would accumulate.

    Widespread use of fludioxonil on turfgrass and outdoor non-containerized ornamentals in Nassau and Suffolk Counties would present an unacceptable risk to the vulnerable sole-source drinking water aquifer. In the absence of groundwater monitoring data, it is the opinion of geological staff that Medallion Fungicide be prohibited from use in Nassau and Suffolk Counties. When groundwater monitoring data is submitted and found to be acceptable, the prohibition issue can be revisited.

    Syngenta Crop Protection, Inc. has agreed to add the following statement to the Medallion Fungicide label:

    The above-mentioned revision will be added to the USEPA Section 3 Medallion Fungicide (EPA Reg. No. 100-769) label via the amendment process. However, the amendment process will take approximately four to five months. Therefore, Syngenta Crop Protection, Inc. has formally requested a voluntary withdrawal of their major change in labeling submission of Medallion Fungicide. Upon gaining USEPA approval, Syngenta Crop Protection, Inc. will resubmit the amended Medallion Fungicide label bearing the above-mentioned New York State specific language to the Department for registration.

    Switch 62.5WG Fungicide is labeled for use on onions and strawberries at a maximum application rate of 0.88 pounds of fludioxonil per acre per year. Onions are primarily grown on muck (organic) soils found in Orange, Oswego, Orleans, Genesee, Madison, Wayne, Yates, and Steuben Counties. Strawberries can grow in a wide variety of soils. They prefer a soil pH between 5.8-6.5 and produce the best yields on deep, fertile soil with a high organic matter content. Therefore, the use of Switch 62.5WG Fungicide in Nassau and Suffolk Counties is not expected to impact the vulnerable groundwater resources when applied to the foliage of onions and strawberries as labeled.

    The Department concludes that Switch 62.5WG Fungicide should not have an adverse effect on the health of workers or the general public, the fish and wildlife resources, or the ground and surface water of New York State when used as labeled.

    Therefore, the Department hereby accepts for registration the new product Switch 62.5WG Fungicide (EPA Reg. No. 100-953) and acknowledges the withdrawal of the application for registration of the revised label for Medallion Fungicide (EPA Reg. No. 100-769).

    Enclosed are your New York State stamped "ACCEPTED" label and a copy of the Certificate of Registration.

    Syngenta Crop Protection, Inc. is reminded that if New York State registration is requested for this product or for any other product which contains fludioxonil with an increased application rate and/or expanded use sites, the product will be considered a Major Change in Labeling and the Department will require an extensive review.

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

Sincerely,

Maureen P. Serafini
Director
Bureau of Pesticides Management

Enclosures
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