SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 2310170
CASRN 2310-17-0
SynonymsPhosalone
Phosphorodithioic acid, S-[(6-chloro-2-oxo-3(2H)-benzoxazolyl)methyl] O,O-diethyl ester
Rubitox
Benzophosphate
Zolone
Molecular FormulaC12H15ClNO4PS2

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use SRP: FORMER USE INSECTICIDE, ACARICIDE, MOLLUSCICIDE Control of chewing and sucking insects and spider mites on pome fruit, stone fruit, citrus fruit, vines, and ornamentals; Colorado beetles on potatoes; aphids on cereals; aphids, bollworms, jassids, thrips, and spider mites on cotton; stem borers, leafhoppers, and planthoppers on rice; thrips and mites on tea; leaf miners on beet; blossom beetles, flea beetles, seed weevils, aphids, and pod midges on brassicas (including oilseed rape); flower midges on lucerne; seed weevils on clover; thrips and stem borers on cardamom; sorghum midges. It is a non-systemic acaricide and insecticide used at 300-600 g ai/100 l against Aphididae, Contrachelus nenuphar, Cydia pomonella, Cydia molesta, Panonychus species, Psylla pyricola, Rhagoletis pomonella, Tetranychus species and Tortricidae on deciduous tree fruits; at 400-800 g/hectare on field and market garden crops; against Aphididae, bollworms, jassids, red spider mites and thrips on cotton; Aphididae and Phthorimaea operculella on potatoes; Meligethes species and weevils on oilseed rape. Pests (including lepidopterous, coleopterous, and piercing/sucking pests) on perennial crops, field crops, vegetables, ornamentals, cotton.
Consumption Patterns ESSENTIALLY 100% AS AN INSECTICIDE FOR FRUITS AND NUTS
Apparent Color CRYSTALS; White; Colorless
Odor SLIGHT GARLIC
Melting Point 47.5-48 DEG C
Molecular Weight 367.80
Sensitivity Data Phosalone is moderately irritating to the skin and eyes.
Environmental Impact Phosalone was a non-systemic acaricide and insecticide recommended for use on fruit trees, field and market crops, cotton, and potatoes. It is not commercially produced in the United States. If phosalone is sprayed on crops, its half-life on the plants may range from <1 to 16 days. Its half-life in soil is 3-7 days. Essentially none of the insecticide is lost by volatilization. In two soils, 8.5 and 9.9% of phosalone was mineralized in 85 days. Metabolism proceeds by oxidation of the phosalone to the oxon, cleavage of the O,O-diethyl methyl phosphorodithioate linkage to form 6-chloro-2-benzoxalinone and ultimately a condensation product that binds tightly to soil. Phosalone's degradation rate in soil increases with the humous content and pH of the soil. If released in water, phosalone would adsorb to sediment and particulate matter in the water column and photolyze in surface layers of water. The rates of other degradative processes in water are unknown. When phosalone is released into the atmosphere as an aerosol during spraying, it will be removed by gravitational settling. It will degrade by direct photolysis to produce phosalone-oxon with an estimated half-life of 86 minutes. Vapor phase phosalone would react with photochemically produced hydroxyl radicals with an estimated half-life of 2.2 hr. Agricultural workers may be exposed to phosalone via inhalation during spraying and via dermal contact during handling or from touching leaves or soil to which the insecticide was applied. The general population may be exposed to phosalone by ingesting fresh or processed fruits that contain phosalone residues, especially apples, pears, and grapes.
Environmental Fate TERRESTRIAL FATE: IN SOIL, INITIAL STAGES WERE APPARENTLY SAME AS IN PLANTS. HOWEVER RED MATERIAL WAS OBSERVED & IDENTIFIED AS SUBSTITUTED PHENOXAZONE. DISULFIDE FORMED BY OXIDATION OF PHOSPHORODITHIOATE. TERRESTRIAL FATE: PHOSALONE WAS INCORPORATED IN MOIST & FLOODED MATAPEAKE LOAM & MONMOUTH FINE SANDY LOAM. IT RAPIDLY DISAPPEARED FROM BOTH SOILS. TERRESTRIAL FATE: If sprayed on plants, phosalone persists for about 14 hr, being converted into the corresponding phosphorothioate which is rapidly hyrolyzed . Another study showed that half-life of phosalone applied to apples, grapes and alfalfa was 2.5, 9.9-16.0, and 4.0 days, respectively . When (phenyl-14C) phosalone was uniformly incorporated into moist (75% field capacity) and flooded Matapeake loam and Monmouth fine sandy loam at 10 ppm and incubated at 22 deg C, it was found that the half-life in soil was 3-7 days . TERRESTRIAL FATE: An analysis of soil extracts and volatilized material, indicate that volatilization was not a major loss mechanism (<0.1%). After 85 days in moist soil, 8.5% and 9.9% of phosalone was converted to CO2, 16.9 and 11.2% were extractable residues, and 74.9 and 79.3% were bound residues. For the flooded soils the values were 0.5 and 2.7%, 11.9 and 11.2%, and 87.6 and 88%, respectively. The bound fraction was primarily associated with the fulvic acids in soil. Approximately 8% of the extractable 14C remaining in the moist Matapeake soil after 85 days was phosalone . Based on the products identified in soil, a metabolic pathway was proposed in which phosalone undergoes extensive binding and condensation in soil, similar to many aniline-based herbicides. Metabolism proceeds by oxidation of the phosalone to the oxon, cleavage of the O,O-diethyl methyl phosphorodithioate linkage to form 6-chloro-2-benzoxalinone, and opening of the heterocyclic ring followed by condensation to form 2-amino-7-chloro-3H-phenoxazin-3-one , the same dimer formed from 4-chloroaniline in soil . TERRESTRIAL FATE: In a Russian study, only 34.7-41.2% of phosalone remained in the upper 5 cm of soil 5 days after application . The concn of phosalane in 15 cm sandy loam soil cores taken from test plots sprayed at 1050 g/ha and 2100 g/ha was 0.293 and 1.18 ppm after application, 0.165 and 0.493 ppm 6 days after application, and 0.072 and 0.121 ppm 14 days after application . The half-life of phosalone in soil at the two application rates was 7 and 5.8 days, respectively . The degradation rate of phosalone in soil increases with the humous content and pH of the soil . AQUATIC FATE: If released in water, phosalone would adsorb to sediment and particulate matter in the water column and photolyze in the surface layers. It would not be expected to bioconcentrate in aquatic organisms. No information is available concerning the degradation rate of phosalone in natural waters. Phosalone is relatively stable to hydrolysis in neutral and acid solution, but hydrolyzes in alkaline solutions to 6-chloro-2-oxobenzoxazole and diethylphosphorothioic acid . ATMOSPHERIC FATE: Phosalone will be released into the atmosphere as an aerosol during spraying and removed by gravitational settling. It will degrade by direct photolysis to produce phosalone-oxon with an estimated half-life of 86 minutes . The reaction rate for photolysis depends on the solar irradiance and will therefore be a function of season, latitude, and cloud cover. Vapor phase phosalone reacts with photochemically-produced hydroxyl radicals resulting in an estimated half-life of 2.2 hr(2,SRC).
Drinking Water Impact GROUNDWATER: In a survey of farm wells in Ontario, Canada, 103 in 1986 and 76 in 1987, phosalone was not detected in any wells at a detection limit of 0.5 ug/l . However, phosalone was only used on crops in 2 farms in 1986 and none in 1987 . In a similar survey of 84 farms in Southern Ontario in 1984, phosalone was also not detected . However, only one farm used phosalone.

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