Phenthoate is an organothiophosphate insecticide. It is used against Lepidoptera, jassids, aphids, soft scales, mosquitoes, blowflies, houseflies, and ked. Phenthoate is an organothiophosphate insecticide. It is used against Lepidoptera, jassids, aphids, soft scales, mosquitoes, blowflies, houseflies, and ked.