Description
Cypermethrin is a synthetic pyrethroid derivative of natural pyrethrins with a good insecticidal action. In vertebrates and invertebrates, cypermethrin acts mainly on the nervous system. It is both a stomach poison and a contact insecticide.
Cypermethrin is used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes. Cypermethrin is used to control pests in soybean, leeks, onions, carrots, turnips, swedes, parsnips, viola spp., spinach, black currant, gooseberries, sunflowers, linseeds, groundnuts, barley, and mushrooms.
Uses
Cypermethrin is a synthetic pyrethroid which is highly used pesticide in agriculture, household and animal husbandry mainly to crack, crevice and spot treatment for control of insects.
Cypermethrin is commonly used to kill household insect pests. In California, it is the fourth most commonly-used insecticide: only chlorpyrifos, pyrethrins, and diazinon have more reported applications.
It is also used in agriculture to control cotton, fruit and vegetable pests. About 90% of cypermethrin is manufactured for cotton crops (WHO, 1998).
Toxicology
Cypermethrin is a moderately toxic material by dermal absorption or ingestion. Symptoms of high dermal exposure include numbness, tingling, itching, burning sensation, loss of bladder control, incoordination, seizures, and possible death. Pyrethroids like cypermethrin may adversely affect the central nervous system. Symptoms of high-dose ingestion include nausea, prolonged vomiting, stomach pains, and diarrhea which progresses to convulsions, unconsciousness, and coma. Cypermethrin is a slight skin or eye irritant, and may cause allergic skin reactions. The oral LD50 for cypermethrin in rats is 250 mg/kg (in corn oil) or 4123 mg/kg (in water). EPA reports an oral LD50 of 187 to 326 mg/kg in male rats and 150 to 500 mg/kg in female rats. The oral LD50 varies from 367 to 2000 mg/kg in female rats, and from 82 to 779 mg/kg in mice, depending on the ratio of cis/trans- isomers present. This wide variation in toxicity may reflect different mixtures of isomers in the materials tested. The dermal LD50 in rats is 1600 mg/kg and in rabbits is greater than 2000 mg/kg.
References
[1] DeeAn Jones, Environmental Fate of Cypermethrin
[2] http://www.inchem.org
[3] http://npic.orst.edu
Description
Cypermethrin is a type II pyrethroid insecticide. It prolongs opening of sodium channels resulting in membrane depolarization and a conductance block of the insect nervous system, and point mutations in sodium channels induce cypermethrin-resistance in house flies, cockroaches, and mosquitos. Cypermethrin (1-1.5 mg) reduces survival of ticks (
H. anatolicum)
in vitro in a concentration-dependent manner. Topical administration of cypermethrin reduces the number of ticks on infested cattle. Cypermethrin (5 and 10 ppm) reduces survival of lice (
D. ovis) in sheep fleece and prevents re-infestation in contact-challenged sheep for 7 and 19 weeks, respectively. It induces developmental neurotoxicities in zebrafish, increasing mortality and edema and inducing body-axis curvature when used at concentrations ranging from 50 to 200 μg/L. Cypermethrin (15 mg/kg twice weekly for 24 weeks) also induces Parkinson''s disease-like neurodegeneration in rats, decreasing locomotor activity, dopamine production, and the number of tyrosine hydroxylase positive (TH
+) neurons in the substantia nigra.
Description
Form: Odorless crystals (pure); yellow-brown viscous semisolid at ambient temperatures (technical grade).
Cypermethrin is a pyrethroid insecticide. It was first synthesized in 1974.
Cypermethrin is a synthetic chemical similar to the pyrethrins in pyrethrum extract (which comes from the chrysanthemum plant). Pyrethroids, including cypermethrin were designed to be effective longer than pyrethrins.
Chemical Properties
Thick, yellow-brown liquid or semisolid mass
(technical product).
Chemical Properties
Viscous Semisolid
Uses
Synthetic pyrethroid insecticide, usually exists as a mixture of cis and trans isomers. Ectoparasiticide
Uses
A potent inhibitor of calcineurin
Uses
Zeta-cypermethrin is used for the control of Lepidoptera, beetles
and aphids in cotton, fruit, vegetables, field crops, ornamentals and
forestry. It is also used in public health.
Definition
ChEBI: A carboxylic ester resulting from the formal condensation between 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid and the alcoholic hydroxy group of hydroxy(3-phenoxyphenyl)acetonitrile.
Agricultural Uses
Insecticide: A U.S. EPA restricted Use Pesticide (RUP) used to control a variety of insects on cotton, fruit and vegetable crops. Also used in commercial and residential settings, ships, laboratories and food processing plants.
Trade name
AMMO®; AGROTHRIN®; ARDAP®; ARRIVO®; AVICADE®; BARRICADE®; CCN52®; CNN 52®; CYMBUSH® 2E; CYMBUSH® 3E; CYMPERATOR®; CYNOFF®; CYPERCARE®; CYPERSECT®; CYPERKILL®; CYRUX®; DEMON®; DORSAN-C® (+cypermethrin); DYSECT®; FASTAC®; FLECTRON®; FMC® 30980; FMC 45497; FMC® 45806; FOLCORD®; IMPERATOR®; JF 5705 F®; KAFIL® SUPER; KENCIS®; NAGATA®; NRDC 149®; NRDC 160®; NRDC 166®; NURELLE; POLYTRIN®; PERMASECT C®; PP383®; PREVAIL®; RALO 10®; RIPCORD®; ROCYPER®; RYCOPEL®; SHERPA®; SIPERIN®; STOCKADE®; SUPERSECT®; TOPCLIPPARASOL®; USTAAD®; WL 43467®; WRDC149®
Biological Activity
Type II synthetic pyrethroid insecticide; an extremely potent, cell-permeable inhibitor of calcineurin.
Contact allergens
Pyrethroids, also called pyrethrinoids, are neurotoxic
synthetic compounds used as insecticides, with irritant
properties. Cypermethrin and fenvalerate have been
reported as causing positive allergic patch tests, but
only fenvalerate was relevant in an agricultural worker.
Potential Exposure
Pyrethroid insecticide used to control
pests on cotton, fruit, and vegetable crops. Also used in
commercial and residential settings, ships, laboratories, and
food-processing plants. A United States Environmental
Protection Agency Restricted Use Pesticide (RUP).
Environmental Fate
Soil. The major soil metabolite was reported to be 3-phenoxybenzoic acid (Hartley and Kidd, 1987).
The typical half-life of cypermethrin in the soil is 30 days, although it can range from two to eight weeks (6, 9). Soil microbes rapidly break down cypermethrin.
Cypermethrin has an extremely low potential to move in the soil. It is unlikely to contaminate groundwater because it binds tightly to soil particles. Cypermethrin is stable in sunlight.
The average half-life of cypermethrin on foliage is 5 days.
United States Environmental Protection Agency. (1989). Cypermethrin Pesticide Fact Sheet. Washington, D.C.
Knisel, W.G. (Ed.). (1993). Groundwater Loading Effects of Agricultural Management Systems. (Version 2.10). [Online]. Tifton, Georgia: United States Department of AgricultureAgricultural Research Service. [Online]. http://www.arsusda.gov/ rsml/ppdb.html
Metabolic pathway
In cabbage plants, (1R)-cis- and (1R)-trans-isomers of
cypermethrin undergo epimerization to (1S)-isomers,
cis=trans isomerization, ester bond cleavage,
hydroxylation of the phenoxy group in the alcohol
moiety or the geminal methyl group in the acid moiety,
hydration of the cyano group to an amido group with
subsequent hydrolysis to the carboxylic acid, and the
conjugation of the carboxylic acid, and alcohols with
sugars.
Shipping
UN3349 Pyrethroid pesticide, solid toxic,
Hazard Class: 6.1; Labels: 6.1-Poisonous material. UN3352
Pyrethroid pesticide, liquid toxic, Hazard Class: 6.1;
Labels: 6.1-Poisonous materials.
Degradation
Zeta-cypermethrin is stable as a solid but it is readily hydrolysed at
alkaline pH. Its half-lives at pH values 7 and 9 (25 °C) were 188-635 and
3 days (PM). By analogy with cypermethrin, the major products should
be 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylica cid (2,
DCVA), 3-phenoxybenzaldehyde (9, 3PBAl) and a-carbamoyl-3-
phenoxybenzyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate
(the amide 3); minor products expected are the a-carboxy analogue of
3 (4) and 3-phenoxybenzoic acid (10,3PBA) (see cypermethrin, Schemes
la and lb).
Photodecomposition would be expected to be similar to that of cypermethrin.
In aqueous solution the DTSo was reported to be 20-36 days
(PM).
Toxicity evaluation
Acute oral LD
50 for rats: 250-4,150 mg/kg (pure); 7,180
mg/kg (technical grade)
Incompatibilities
May react violently with strong oxidi-
zers, bromine, 90% hydrogen peroxide, phosphorus
trichloride, silver powders, or dust. Incompatible with silver
compounds. Mixture with some silver compounds forms
explosive salts of silver oxalate.
Waste Disposal
Incineration would be an
effective disposal procedure where permitted. If an efficient incinerator is not available, the product should be mixed
with large amounts of combustible material and contact
with the smoke should be avoided. In accordance with 40
CFR 165, follow recommendations for the disposal of pes-
ticides and pesticide containers.
