Abstract: Disclosed is both a method and composition for controlling deleterious organisms, such as insects, nematodes and weeds by applying a compound comprised of both mono-iodinated hydrocarbons and di-iodinated hydrocarbons. The combination provides an effective insecticide and nemacide along with herbicidal properties without causing significant harm to the ozone layer. Additionally disclosed is a method of soil fumigation comprising applying to a soil an effective amount of a fumigant selected from diiodinated hydrocarbons, polyiodinated hydrocarbons and their combinations.