The information in this profile may be out-of-date. It was last revised
in 1996. EXTOXNET no longer updates this information, but it may be useful
as a reference or resource.
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EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Tradenames for disulfoton include Bay S276, Disyston, Disystox,
Dithiodemeton, Dithiosystox, Frumin AL, Solvigram, and Solvirex.
All products formulated at greater than 2% disulfoton are
classified as Restricted Use Pesticides (RUPs). RUPs may be
purchased and used only by certified applicators. Disulfoton is
classified as Toxicity class I- highly toxic. Products containing
disulfoton bear the Signal Word DANGER.
Disulfoton is a selective, systemic organophosphate insecticide
and acaricide that is especially effective against sucking
insects. It is used to control aphids, leafhoppers, thrips, beet
flies, spider mites, and coffeeleaf miners. Disulfoton products
are used on cotton, tobacco, sugar beets, cole crops, corn,
peanuts, wheat, ornamentals, cereal grains, and potatoes.
- Acute toxicity: Disulfoton is very
highly toxic to all mammals by all routes of exposure.
Whether absorbed through the skin, ingested, or inhaled,
early symptoms in humans may include blurred vision,
fatigue, headache, dizziness, sweating, tearing, and
salivation. It inhibits cholinesterase and affects
nervous system function [2,8]. Symptoms occurring at high
doses include defecation, urination, fluid accumulation
in the lungs, convulsions, or coma. Death can occur if
high doses stop respiratory muscles or constrict the
windpipe [2,8]. Ingestion of high doses can lead to rapid
onset of effects on the stomach. Symptoms resulting from
skin exposure may be delayed for up to 12 hours. Complete
recovery from acute effects takes at least week, but
complete restoration of the blood to normal cholinestrase
enzyme levels may take up to 3 months . The oral LD50
ranges from 6.2 to 12.5 mg/kg in male rats and from 1.9
to 2.5 mg/kg in female rats [1,59]. For weanling male
rats, the oral LD50 is 5.4 mg/kg . The dermal LD50 is
3.6 mg/kg in female rats and 15.9 mg/kg in male rats
. The inhalation LC50 for 1 hour is 0.3 mg/L in male
- Chronic toxicity: Rats have survived
daily doses of 0.5 mg/kg/day for 90 days. Some studies
have shown that rats can acquire a tolerance for the
chemical, so they are able to adjust to the lower
cholinesterase levels resulting from chronic low level
exposures . In a 2-year rat study, males fed
disulfoton (95.5% pure) daily at levels below the LD50
had increased spleen, liver, kidney, and pituitary
weights, while females with similar treatment had
decreased weights in these organs. Also, at all dietary
levels, male brains decreased in weight while female
brain weights increased. At the highest doses,
cholinesterase activity was inhibited in both sexes in
the brain, plasma, and red blood cells . In a
23-month mouse study, kidney weights increased in females
fed high daily doses. At that level, cholinesterase
activity was decreased in both sexes .
- Reproductive effects: In a long-term
reproduction study, 98.5% pure disulfoton was fed at a
dose of 0.5 mg/kg/day to both male and female albino
rats. The number of animals per litter was reduced by 21%
in the first and third generations and a 10 to 25% lower
pregnancy rate was noted. Some third-generation litters
whose parents were exposed to this dose developed fatty
deposits and swelling in their livers. Exposed adults and
litters had a 60% to 70% inhibition of red blood cell
cholinesterase . This suggests that disulfoton is
unlikely to cause reproductive effects in humans at
expected exposure levels.
- Teratogenic effects: In one study,
pregnant rats were given disulfoton (98.2% pure) at doses
ranging from 0.1 to 1.0 mg/kg/day through a stomach tube
during the sensitive period of gestation. Cholinesterase
activity was decreased. In the fetuses, no developmental
defects were seen except at high doses, where incomplete
bone development was noted [59,60]. In another study,
rabbits were given disulfoton (97.3% pure) during the
sensitive period. At the higher doses (1.5 and 2.0
mg/kg/day) fetal growth was not affected . These
studies indicate that disulfoton is unlikely to cause
- Mutagenic effects: Disulfoton has been
shown to be mutagenic in studies on bacteria .
- Carcinogenic effects: There is no
evidence that disulfoton is carcinogenic. Studies of rats
and mice fed high doses for 2 years did not show
significant tumor growth [59,60].
- Organ toxicity: Continual daily
absorption may cause flu-like symptoms, loss of appetite,
weakness, and uneasiness. While repeated exposure to
disulfoton may inhibit the cholinesterase enzyme and thus
interfere with the nervous system, 30-day human exposures
have not resulted in significant enzyme inhibition .
Workers chronically exposed to organophosphates like
disulfoton have developed irritability, delayed reaction
times, anxiety, slowness of thinking, and memory defects
. Chronic exposure of workers may also lead to
- Fate in humans and animals: Disulfoton
is rapidly absorbed by the gastrointestinal tract,
metabolized, and excreted via urine. In one study, in
which both male and female rats received single doses,
females excreted the chemical at a slower rate than did
the males. Males excreted 50% of the dose in the urine
within 4 to 6 hours after dosing, while it took females
30 to 32 hours to excrete 50% through the urine. Within
10 days after dosing, both male and female rats lost, on
average, 81.6% of the initial dose via the urine, 7.0% in
the feces, and 9.2% in expired air .
- Effects on birds: Disulfoton is
moderately toxic to birds. The 5-day acute dietary LC50
for disulfoton is 692 ppm in mallard ducks, and 544 ppm
in quail .
- Effects on aquatic organisms:
Disulfoton-containing products are highly toxic to cold
and warm fish, crab, and shrimp . The LC50 values for
the compound are 0.038 mg/L in bluegill sunfish, 0.25
mg/L in guppies, 1.85 mg/L in rainbow trout, and 6.5 mg/L
in goldfish . The bioconcentration factor of 460
indicates that there is a low to moderate potential for
this compound to concentrate in living organisms .
- Effects on other organisms: Use of
disulfoton on certain crops may pose a risk to some
aquatic and terrestrial endangered species .
Disulfoton is toxic to bees.
- Breakdown in soil and groundwater:
Disulfoton has a low to moderate persistence in soils.
Disulfoton is not strongly bound to soil [8,19]. Some
metabolites are more mobile than the parent disulfoton in
sandy loam, clay loam, and silty clay loam soils.
Mobility decreases as organic matter content of soil
increases. In addition, these metabolites can persist
longer than disulfoton. In a study on sandy loam soils,
disulfoton had a half-life of 1 week, and 90% loss in 5
weeks. One metabolite had a half-life of 8 to 10 weeks,
and another was fairly stable for 42 weeks .
Disulfoton has been found in groundwater in in Virginia
and Wisconsin at levels up to 1 mg/L .
- Breakdown in water: Like other
organophosphorous insecticides, disulfoton will break
down in water under alkaline conditions, and is most
stable at normal surface water acidities. The degradation
of the compound is temperature dependent .
- Breakdown in vegetation: When applied to
the soil, disulfoton is actively taken up by plant roots
and is translocated to all parts of the plant . Such
systemic distribution is especially effective against
sucking insects, while predators and pollinating insects
are not destroyed. Control may persist for 6 to 8 weeks
[60,61]. Breakdown in plants follows the same chemical
pathway as in soil.
- Appearance: Disulfoton, a member of the
organophosphate chemical family, is a yellowish oil .
- Chemical Name: O,O-diethyl
- CAS Number: 298-04-4
- Molecular Weight: 274.40
- Water Solubility: 25 mg/L @ 23 C 
- Solubility in Other Solvents: soluble in
most organic solvents and fatty oils 
- Melting Point: 25 C 
- Vapor Pressure: 24 mPa @ 20 C 
- Partition Coefficient: Not Available
- Adsorption Coefficient: 600 (estimated)
- ADI: 3 x 10-3 mg/kg/day 
- MCL: Not Available
- RfD: 4 x 10-5 mg/kg/day 
- PEL: Not Available
- HA: 3 x 10-4 mg/L 
- TLV: 0.1 mg/m3 (8-hour) (skin) 
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- Phone: 905-639-7535
- Emergency: Not Available
References for the information in this PIP can be found in
Reference List Number 5
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide