Diazinon

Overview
Diazinon (O,O-diethyl-O-(2-isopropyl-6-methyl-pyrimidine-4-yl)phosphorothioate), a colorless to dark brown liquid, is a thiophosphoric acid developed in 1952 by Ciba-Geigy, a Swiss chemical company (later Novartis and then Syngenta). It is a nonsystemic organophosphate insecticide formerly used to control cockroaches, silverfish, ants, and fleas in residential, non-food buildings. Bait was used to control scavenger wasps in the western U.S. Residential uses of diazinon were cancelled in 2004; it is still approved for agricultural uses.

Diazinon kills insects by inhibiting acetylcholinesterase, an enzyme needed for proper nervous system function. Diazinon has a low persistence in soil. The half-life is 2 to 6 weeks. The symptoms associated with diazinon poisoning in humans include weakness, headaches, tightness in the chest, blurred vision, nonreactive pinpoint pupils, excessive salivation, sweating, nausea, vomiting, diarrhea, abdominal cramps, and slurred speech.

In 1988, the Environmental Protection Agency prohibited the use of Diazinon on golf courses and sod farms because of decimation of bird flocks that congregated in these areas. In the United States as of December 31, 2004, it became unlawful to sell diazinon outdoor, non-agricultural products. It is still legal for consumers to use diazinon products purchased before this date, provided that they follow all label directions and precautions.

Among cultivators of carnivorous plants, diazinon is known as the most effective systemic insecticide, capable of eradicating severe infestations of aphids, mealybugs and other sucking parasites while leaving the plant unharmed. For cultivators unable to obtain diazinon, Malathion and Acephate (Orthene) have been reported as less effective substitutes.