| Chemical Abstract Number (CAS #) |
17804352
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| Synonyms | Benomyl |
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Benlate | Benzimidazolecarbamic acid, 1-(butylcarbamoyl)-, methyl ester |
| Analytical Method |
EPA Method 631 |
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| Molecular Formula | C14H18N4O3 |
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| Use | FUNGICIDE, ASCARICIDE; ACTIVITY AS CATALYST IN BIOLOGICAL OXIDN
OF SEWAGE & FERTILIZERS.
FOR THE CONTROL OF CERTAIN DISEASES OF ROSES, FLOWERS, ORNAMENTALS
& TURF; DIP TREATMENT OF PINEAPPLE SEED PIECES. PROMISING FOR CONTROL
OF WIDE RANGE OF DISEASES OF VEGETABLE & FRUIT CROPS.
Benomyl is used as a protective and eradicant fungicide with systemic activity, effective against a
wide range of fungi affecting field crops, fruits, nuts, ornamentals and turf. It is also effective
against mites and is used as pre- and post-harvest sprays or dips for the control of storage rots of
fruits and vegetables.
Medication (Vet).
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| Consumption Patterns | 100% USED AS A FUNGICIDE (1975)
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| Apparent Color | WHITE, CRYSTALLINE SOLID
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| Odor | Faint acrid odor
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| Molecular Weight | 290.36
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| Sensitivity Data | It is mildly irritating to the skin
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| Environmental Impact | Benomyl is used as a protective and eradicant fungicide and is effective againsta wide
range of fungi that affect field crops, fruits, nuts, ornamentals and turf. Benomyl released to soil
will not tend to leach but volatilization of benomyl from soil may be significant. Hydrolysis of
benomyl in soil is probably the most significant removal process although biodegradation may also
be significant, especially for the benomyl hydrolysis products. Benomyl released to water will have
a low to moderate tendency to sorb to sediments, suspended sediments and biota and will not tend
to bioconcentrate to any significant extent. Volatilization of benomyl from water is probably
insignificant. Hydrolysis will probably be the most significant removal process for benomyl in
water (t 1/2 <1 week) although biodegradation and photolysis may also be important. A computer
estimated half-life for reaction of benomyl in the vapor phase with photochemically produced
hydroxyl radicals in the atmosphere is 1.6 hours. Humans may be exposed to benomyl through
dermal contact where it is mixed and used, through the inhalation of dust particles to which it has
sorbed in fields, and from dermal contact from picking fruits and vegetables that have been
sprayed with benomyl.
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| Environmental Fate | TERRESTRIAL FATE: Benomyl released on or into soils will not move downward or
leach extensively(1,2,3). Volatilization of benomyl from soil may be significant (estimated vapor
loss of benomyl from soil was 3.5 to 6.5 kg/ha/yr or more) . Benomyl in soil is easily
hydrolyzed to methylbenzimidazole-2-ylcarbamate (carbendazim; MBC) . Bacteria and fungi
that can degrade benomyl have been isolated from garden soil(6). Mixed cultures(7) and pure
cultures of Psuedomonas strains(8) that can grow on benomyl as the sole carbon source have been
isolated from water and soil. Intact benomyl, applied as a solid in aqueous suspension,
decomposes rapidly in soil. Four weeks after the application of 5 pounds of benomyl/acre to soil
in Florida, North Carolina and Delaware, no intact benomyl was found in the Florida and
Delaware soils and only 7% remained in the North Carolina soil. The major and minor
degradation products were methyl 2-benzimidazolecarbamate (MBC) and 2-aminobenzimidazole
(AB), respectively . The half-life of the benzimidazole-containing residues was about 3-6
months on turf and about 6-12 months on bare soil . In another study, degradation of benomyl
occurred within 15 days in unsterilized soil .
AQUATIC FATE: Benomyl released to water will have a low to moderate tendency to sorb to
sediments, suspended sediments and biota and will not tend to bioconcentrate (log Kow = 2.42
and 3.11 ). No information was found about volatilization from water. In water, benomyl will
hydrolyze(3,4). One study reported that the conversion of benomyl (approx 40 ppm) to methyl
2-benzimidazole carbamate (MBC) was complete within one week . Since benomyl has an
absorption maximum at 294 nm , it may photodegrade in water. Mixed cultures from
water were able to use benomyl as a sole carbon source but the degradation rate was slow(6).
ATMOSPHERIC FATE: Benomyl may enter the atmosphere in the vapor phase or sorbed to
particulate matter. A computer estimated half-life for benomyl in the vapor phase in the
atmosphere is 1.6 hours due to reaction with photochemically generated hydroxyl radicals .
EFFL: Benomyl or its degradation product were detected leachate near a pesticide plant in
Barcelona, Spain in concn range of 5-10 ppm .
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