Microemulsion insecticides that do not contain conventional actives kill insects by an oil/surfactant combination that when applied to the surface of a crawling insect cause it to flip over onto its back. The microemulsion includes 20% to 60% by weight of a hydrocarbon solvent, 1% to 20% by weight of a surfactant, and at least 10% by weight of water. The conventional actives that are not included in the microemulsion are insecticidally active synthetic pyrethroids, pyrethrum, organophosphates, carbamates, chlorinated hydrocarbons, and heterocyclics.