Environmental Fate and Toxicology of Dimethoate

The insecticide dimethoate, an organophosphate, was first introduced in 1962 for broad spectrum control of a wide range of insects including mites, flies, aphids, and plant hoppers. It is known to inhibit AChE activity like other organophosphates, resulting in nerve damage which may lead to death. In the environment, hydrolysis represents a major degradation pathway under alkaline conditions, whereas volatilization is not a major route of dissipation from either water or moist soils. Dimethoate is also degraded by microbes under anaerobic conditions and the major degradation product, omethoate, has been identified. Dimethoate has been found to adversely impact many organisms. In plants, photosynthesis and growth are highly impacted, whereas birds exhibit inhibition in brain enzyme activity, thus sublethal effects are apparent. Aquatic organisms are expected to be highly impacted via direct exposure and display changes in swimming behavior.