Allethrin

Allethrin is a synthetic pyrethroid insecticide derived from the natural insecticide pyrethrin, which is found in chrysanthemum flowers. It was first synthesized in the 1970s as a more stable and cost-effective alternative to natural pyrethrins. Allethrin is widely used in household insecticides, particularly in aerosol sprays, due to its effectiveness against flying insects such as mosquitoes, flies, and moths.

The chemical structure of allethrin mimics that of natural pyrethrins but is modified to enhance stability and reduce degradation in sunlight. It acts on the nervous system of insects by binding to sodium channels in nerve cells, disrupting normal electrical signaling and leading to paralysis and death. Allethrin is classified as a type I pyrethroid, which means it causes rapid knockdown effects but may require repeated exposure for lethal results.

Due to its low mammalian toxicity, allethrin is generally considered safe for human use when applied according to label instructions. However, it can cause skin irritation or allergic reactions in sensitive individuals. Environmental concerns have been raised regarding its potential impact on non-target organisms, particularly aquatic life, though its effects are generally less pronounced than those of older insecticides like DDT.

Allethrin is commonly found in consumer products such as insecticide sprays, coils, and mats. Its use is regulated in many countries, with restrictions often placed on outdoor applications to minimize ecological risks. Research continues into its long-term effects and the development of resistance in insect populations.