Water-based Aerosol Insecticides Containing Dimethyl Ether as a Propellant

Abstract

The stability and the biological efficacy of water-based aerosol formulations containing dimethyl ether as propellant were examined by using various insecticides. Stability varied from the most stable d-phenothrin to the most unstable fenitrothion, depending on their chemical structures. Electron-withdrawing substituents were suggested to activate the ester bonds of pyrethroids to hydrolyze. The biological efficacy of the formulations against houseflies and mosquitoes was almost equal to that of water-based aerosol formulations containing LPG (propane/butane) as propellant, except that the knockdown efficacy of tetramethrin against mosquitoes was lower than that of the formulations containing LPG. A combination of d-allethrin as a knockdown insecticide with a stable killing pyrethroid such as d-phenothrin, d-cyphenothrin, d-resmethrin or permethrin will make promising water-based aerosol formulations containing dimethyl ether, followed by a combination of prallethrin with a stable killing pyrethroid.