Allethrin is used almost exclusively in homes and gardens for control of flies and mosquitoes, and in combination with other pesticides to control flying or crawling insects. The purified d-trans-isomer of allethrin is more toxic to insects and is used for control of crawling insects in homes and restaurants.
Allethrin is a synthetic duplicate of a component of pyrethrum. Pyrethrum is a botanical insecticide extracted from chrysanthemum flowers. Allethrin, the first synthetic pyrethroid, was introduced in 1949, and is a mixture of several isomeric forms. The most common form is a 4:1 mixture of the trans- and cis-isomers. It is available in aerosol, coil, mat, dust and oil formulations. Aerosol and spray formulations of the purified d-trans- isomer of allethrin are also available. D-trans allethrin is usually combined with synergists such as piperonyl-butoxide.
Allethrin is slightly to moderately toxic by dermal absorption and ingestion. Short-term dermal exposure to allethrin may cause itching, burning, tingling, numbness, a feeling of warmth, with no dermatitis. Exposure to large doses by any route may lead to nausea, vomiting, diarrhea, hyperexcitability, incoordination, tremors, convulsive twitching, convulsions, bloody tears, incontinence, muscular paralysis, prostration and coma. Persons sensitive to ragweed pollen are at increased risk from exposure to allethrin
Allethrin is practically non-toxic to birds. Allethrin is highly toxic to fish and aquatic invertebrates.
Read more: Insecticides