Home

DEET

Permethrin

Natural Insecticides

Links

Permethrin is a powerful, rapidly acting insecticide,similar in structure to natural pyrethrim insecticide derived from the crushed and dried flowers of the daisy Chrysanthemum cinerariifolium. Permethrin is a human-made synthetic pyrethroid. It does not repel insects like DEET does but works as a contact insecticide, causing nervous system toxicity that leads to the death or "knockdown" (out of the air) of the insect. The chemical is effective against mosquitoes, flies, ticks, and chiggers. Permethrin has low toxicity in mammals, is poorly absorbed by the skin, and is rapidly inactivated by ester hydrolysis(the insect can quickly get rid of it so it does not necessarily kill.

Permethrin should be applied directly to clothing or other fabrics (such as tent walls or mosquito nets, not to skin. The spray form is nonstaining, nearly odorless, and resistant to degradation by heat or sun and maintains its potency for at least 2 weeks, even through several washings. In a field trial conducted in Alaska, persons wearing permethrin-treated uniforms and a polymer-based 35% DEET product had more than 99.9% protection (1 bite per hour) over 8 hours, even under conditions of intense biting pressures; unprotected persons received an average of 1188 bites per hour.

Molecular Formula: C₂₁H₂₀Cl₂O₃

Synonyms:

Ambush; Ectiban; Pounce; 3-(2,2-Dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (3-phenoxyphenyl)methyl ester; (3-phenoxyphenyl)methyl (+/-)-cis,trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate.

Physical Properties:

Is Permetrin Safe?

Permethrin should be applied to clothing or other fabrics. It is not intended for direct application to the skin. Once Permethrin has dried on the clothing it bind very strongly to the fibres and absorption through the skin is negligible.

Any permethrin that may get on the skin inadvertently is poorly absorbed (less than 2% of applied dose). It is rapidly inactivated by skin and liver esterases, its metabolites are then excreted by the kidneys. Occupational exposure to high doses of permethrin has been associated with symptoms of of itching, burning and numbness. Studies have shown permethrin not to be a human teratogen, mutagen, or carcinogen.

Permethrin is also environmentally safe as it is degraded by sunlight, its half life is less than 30 days in soil and the chemical is readily metabolized by soil microorganisms.

More Molecules of the Month