Chlorpyrifos-methyl (CAS 5598-13-0)

Chlorpyrifos-methyl, an organophosphate insecticide, demonstrates remarkable efficacy against adult stored-grain pests. When applied to grain at a dose of 10 mg/kg, it induces mortality rates of 100%, 100%, 63%, and 97.3% for L. bostrychophila, L. decolor, L. entomophila, and L. paeta, respectively. Moreover, at a lower dose of 2.5 mg/kg, it significantly reduces the number of live progeny produced by these pests, resulting in reductions of 100%, 100%, 30.4%, and 41.1%, respectively. Additionally, research involving pregnant female mice has revealed that administration of chlorpyrifos-methyl (at doses ranging from 4 to 100 mg/kg) leads to altered H19 gene methylation in sperm. This alteration is accompanied by changes in male offspring, including decreased anogenital distance, increased thymus and epididymis weights, and higher serum testosterone levels. Chlorpyrifos-methyl, known chemically as O,O-dimethyl hydrogen phosphorothioate with a 3,5,6-trichloropyridin-2-yl group replacing the hydrogen of the hydroxy group, serves various roles such as an agrochemical, an EC 3.1.1.7 (acetylcholinesterase) inhibitor, an environmental contaminant, a xenobiotic, an acaricide, and an insecticide. It appears as colorless crystals and has corrosive properties towards copper, brass, iron, and tin plate. Due to its insecticidal properties, formulations containing chlorpyrifos-methyl have been utilized to manage stored-grain pests and mosquito populations.