SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 298044
CASRN 298-04-4
SynonymsDisulfoton
Phosphorodithioic acid, O,O-diethyl S-[2-(ethylthio) ethyl] ester
O,O-Diethyl S-[2-(ethylthio)ethyl] phosphorodithioate
Disyston
Analytical Method EPA Method 8141
Molecular FormulaC8H19O2PS3

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

Use INSECTICIDE FOR MITES & APHIDS ON SMALL GRAINS, CORN & SORGHUM, COTTON, OTHER FIELD CROPS, VEGETABLES, FRUIT & NUTS, ORNAMENTALS SYSTEMIC INSECTICIDE & ACARICIDE RECOMMENDED FOR COTTON, BEETS, POTATOES, HOPS, VEGETABLES, ORNAMENTALS AGAINST WIDE RANGE OF INSECTS & MITES. SHOWS SOME NEMATICIDAL ACTION WHICH MAY PERSIST FOR 6-12 WK. Application sites: Cole crops, root crops, pome, strawberry and pineapple fruits, forage, field and vegetable crops, sugarcane, seed crops, forest plantings, ornamentals, and potted plants (including houseplants). Control of aphids, thrips, mealybugs, and other sucking insects, and spider mites in cereals, maize, sorghum, rice, soya beans, groundnuts, lucerne, clover, sugar beet, hops, cotton, coffee, tobacco, fruit and nut crops, and forestry nurseries. Also prevents cucumber mosaic and potato leaf roll viruses by controlling the virus vectors. Side dressing, broadcast, in the seed furrow or foliar spray to control many insect, mite species. Seed treatment for sucking insects.
Consumption Patterns 65% AS AN INSECTICIDE FOR MITES & APHIDS ON SORGHUM; 33% AS AN INSECTICIDE FOR MITES & APHIDS ON SMALL GRAINS, CORN, COTTON, OTHER FIELD CROPS, VEGETABLES, FRUIT, & NUTS; 2% AS AN INSECTICIDE FOR MITES & APHIDS IN HOME & GARDEN USE (ON ORNAMENTALS) (1974) Wheat, 23.4%; Broccoli, 20.1%; Cauliflower, 6.9%; Cotton, 10.6%; Lettuce, 12.5%; Turf, 5.5%; most of remainder used in production of other cole crops, other cereals and sugarbeets (1984) /California use, calculated from table (1974) 2.5X10 9 G (CONSUMPTION) (1984) 1.04x10 8 g Used in California
Apparent Color OILY, COLORLESS LIQUID ; Pure compound: yellow liquid
Odor CHARACTERISTIC OF SULFUR CMPD
Boiling Point 132-133 DEG C @ 1.5 MM HG, 108 DEG C @ 0.01 MM HG
Melting Point GREATER THAN -25 DEG C
Molecular Weight 274.38
Density 1.144 @ 20 DEG C/4 DEG C
Environmental Impact Release of disulfoton to the environment probably occurs primarily during its use as an insecticide in crops of tobacco and edible foods including carrots, cucumbers, parsley, peas, and potatoes and other potential sources of release include losses during manufacturing, formulation, packaging and disposal of this pesticide. If released to soil, disulfoton will be rapidly oxidized by chemical reaction and possibly microbial metabolism to its corresponding sulfoxide and sulfone. Humic substances are expected to photosensitize chemical oxidation of this compound on soil surfaces. The half-life of disulfoton in soil is reported to range between 1 to 4 days. This compound should have little or no mobility in soil and is not expected to undergo chemical hydrolysis in moist soils with pH <8 or volatilize significantly from soil surfaces. If released to water, disulfoton will be oxidized to its corresponding sulfoxide and sulfone by reaction with photochemically generated singlet oxygen and possibly hydroxyl radicals. Humic substances are expected to photosensitize chemical oxidation of disulfoton. The half-life in water containing large amounts of humic substances ranges from 5 hours during summer to 12 hours during winter. Disulfoton has the potential to strongly adsorb to suspended solids and sediments and is not expected to undergo chemical hydrolysis at pH <8, bioaccumulate in aquatic organisms or volatilize significantly (estimated half-life 23 days). If released to the atmosphere, disulfoton is expected to exist in both vapor and particulate form. It may be oxidized by photochemically generated hydroxyl radicals (estimated vapor phase half-life 12.7 hours) or be physically removed by settling or washout in precipitation. Removal by direct photolysis should not be significant. The most probable routes of exposure to disulfoton by the general population are ingestion of contaminated foods and inhalation. Workers involved in the manufacture, handling or application of this compound may be exposed by dermal contact or inhalation.
Environmental Fate TERRESTRIAL FATE: If released to soil, disulfoton will be rapidly oxidized by chemical reaction and possibly microbial metabolism to its corresponding sulfoxide and sulfone. Humic substances found in soil are reported to photosensitize chemical oxidation of disulfoton. Added to Portneuf silt loam at a concn of 10 and 125 ug/g soil had a half-life of 1 to 2 days and was oxidized to its sulfoxide and sulfone . Granular disulfoton applied in-furrow to soil at a rate of 0.5 kg active ingredient/ha was rapidly oxidized with 1, 0.13, and <0.01 ppm disulfoton (dry basis) recovered 14, 21, and 56 days after application, respectively . Disulfoton should have little or no mobility in soil and is not expected to undergo chemical hydrolysis in moist soils with pH <8 or volatilize significantly from soil surfaces. AQUATIC FATE: If released to water, disulfoton will be oxidized to its corresponding sulfoxide and sulfone by reaction with photochemically generated singlet oxygen and possibly hydroxyl radicals. Humic substances are expected to photosensitize oxidation of disulfoton. The half-life of disulfoton in Aucilla River water (colored water) ranges from 5 hours during summer to 12 hours during winter . Disulfoton has the potential to strongly adsorb to suspended solids and sediments and is not expected to undergo chemical hydrolysis at pH <8, bioaccumulate in aquatic organisms or volatilize significantly (estimated half-life 23 days). ATMOSPHERIC FATE: If released to the atmosphere, disulfoton is expected to exist in both vapor and particulate form. It may be oxidized by photochemically generated hydroxyl radicals (estimated vapor phase half-life 12.7 hours) or be physically removed by settling or washout in precipitation. Disulfoton is not expected to undergo direct photolysis. Measurable residues of the sulfoxide, sulfone, and oxygen analog of the sulfone of disulfoton/ were also present in the soil 2 years after application. Disulfoton was incubated with various soils. A number of products were formed but only disulfoton sulfone persisted in soil. The fate of disulfoton in Portneuf silt loam soil was studied. Oxidation of this compound to the sulfoxide and sulfone was observed. The half-life of disulfoton was approximately 2 days but varied somewhat with temperature and moisture. Disulfoton sulfone persisted for more than 64 days; the disulfoton and its sulfoxide 32 days or less. The corresponding oxygen analogs of the metabolites were not observed. Terrestrial Fate: Disulfoton is metabolized in soil to the sulphoxide and sulphone, to the corresponding phosphorothioate analogs (of demeton-S), and finally, to derivatives of O,O-diethyl hydrogen phosphate and 2-ethylthioethyl mercaptan.

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