Selected studies in chemical ecology are described that have led to the identification of semiochemicals playing key roles in pest behaviour. In some instances, these compounds can provide alternatives to insecticides, but novel integrated control programmes including use of semiochemicals are described which have greater potential for the future. Thus, semiochemicals can be used to increase the efficacy of entomophagous fungi and to manipulate populations of beneficial insects. New strategies are being developed which use both antifeedant and attractant semiochemicals to deter insects from crops and aggregate them in areas where they can be destroyed. For the long term, strategies are described that employ genetic manipulation of crop plants so that pests are controlled by semiochemicals produced directly in the plants.