malathions

Malathion is an organophosphate insecticide widely used in agriculture, urban pest control, and public health programs. It is applied in various formulations, including emulsifiable concentrates, granules, and ultra-low-volume sprays. The chemical acts by inhibiting acetylcholinesterase, an enzyme essential for nerve signal transmission, leading to the accumulation of acetylcholine and overstimulation of the nervous system in insects. Mammals are generally less sensitive because they detoxify malathion more efficiently, though exposure can still be hazardous.

In some organisms and environmental conditions, malathion can be metabolically activated to malaoxon, a more potent acetylcholinesterase inhibitor. This metabolite can contribute to the overall toxicity of malathion in certain contexts, affecting both target pests and non-target species.

Common uses include protection of fruits, vegetables, nuts, and ornamental crops from a range of insects, as well as vector-control efforts in malaria and dengue programs in some regions. Pre-harvest intervals and label directions determine where and when malathion may be applied. Integrated pest management approaches often emphasize rotation with other modes of action to reduce resistance development.

Environmental fate is characterized by relatively rapid degradation in soil and water through hydrolysis and photolysis, though persistence and toxicity can vary with temperature, pH, and sunlight. Malathion is moderately toxic to aquatic invertebrates and fish, and care is advised to minimize spray drift and runoff into water bodies. It can also affect non-target pollinators if exposure occurs during blooming periods.

Regulatory oversight varies by country; malathion products are typically registered with usage instructions, safety precautions, and restrictions designed to limit human and environmental risk. In cases of exposure or poisoning, antidotal treatment may involve atropine and, in certain circumstances, oxime therapies.