there is disclosed a spray apparatus for holding contents comprising diatomaceous earth and a compressed propellant for propelling the diatomaceous earth . there is also disclosed use of diatomaceous earth to control a population of bedbugs , wherein the diatomaceous earth comprises remains of pennate diatoms . there is also disclosed a method of controlling a population of insects , the method comprising causing a compressed propellant to propel diatomaceous earth on a surface . method of manufacturing a spray apparatus and methods of preparing diatomaceous earth for use in controlling a population of insects are also disclosed .