| Chemical Abstract Number (CAS #) |
298044
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| Synonyms | Disulfoton |
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Phosphorodithioic acid, O,O-diethyl S-[2-(ethylthio) ethyl] ester | O,O-Diethyl S-[2-(ethylthio)ethyl] phosphorodithioate | Disyston |
| Analytical Method |
EPA Method 8141A |
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| Molecular Formula | C8H19O2PS3 |
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| 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.
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| 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
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| Apparent Color | OILY, COLORLESS LIQUID ; Pure compound: yellow liquid
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| Odor | CHARACTERISTIC OF SULFUR CMPD
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| Boiling Point | 132-133 DEG C @ 1.5 MM HG, 108 DEG C @ 0.01 MM HG
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| Melting Point | GREATER THAN -25 DEG C
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| Molecular Weight | 274.38
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| Density | 1.144 @ 20 DEG C/4 DEG C
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| 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.
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| 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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