Temephos is an nonsystemic organophosphorus insecticide used to control mosquito, midge, and black fly larvae. It is used in lakes, ponds, and wetlands. It also may be used to control fleas on dogs and cats and to control lice on humans. Temephos is available as 50% emulsifiable concentrates, 50% wettable powder, 5% and 1% granular forms.