Using pheromones to disrupt mating of moth pests

Introduction Many kinds of insects rely on sex pheromones to locate mates, with attraction often occurring over distances of ten meters or more. The prospect of achieving direct population control of insect pests by applying synthetic copies of these attractants to a crop has long intrigued entomologists and chemists. Because odor communication is mediated by miniscule quantities of pheromone, it was imagined that application of relatively small amounts of synthetic pheromone, perhaps a fraction of a gram of pheromone per ha per day, would readily interfere with mate location by “confusing” the responders. But testing the feasibility of mating disruption requires synthetic copies of these chemical messages, and it was not until the late 1960s and early 1970s that advances in techniques for characterizing pheromone structures facilitated the identification of the pheromones of many of the world's most damaging pest insects. The availability of synthetic pheromones in turn enabled field testing of this method of pest control, beginning with Gaston et al . (1967). Female-emitted pheromones that induce mate-location behaviors in males are now known for hundreds of moth species (Arn et al ., 2000), and for insects in many other groups (Mayer and MacLaughlin, 1991). Although some moth species have pheromones consisting of a single compound, most moth pheromones are blends of two to four components. The majority of compounds utilized are unbranched alkyl chains, 10 to 18 carbons in length, most always with an even number of carbons, one or two double bonds, and with a terminal acetate, alcohol, or aldehyde moiety.