Developing sustainable pest control from chemical ecology

Abstract

The study of chemical ecology, particularly involving pheromones and other semiochemicals that influence insect behaviour, promises methods of pest control as alternatives to the exclusive use of broad-spectrum toxicants. However, if the potential of semiochemicals in crop protection is to be realised, a greater understanding of insect/insect and insect/plant interactions, and insect chemical ecology generally, is essential. Semiochemicals, when employed alone, often give ineffective or insufficiently robust pest control. Use of semiochemicals should therefore be combined with other approaches in integrated management strategies. The main components of such strategies are pest monitoring, to allow accurate timing of pesticide treatments; combined use of semiochemicals, host plant resistance and trap crops, to manipulate pest behaviour; selective insecticides or biological control agents, to reduce pest populations. The objective is to draw together these approaches into a push-pull or stimulo-deterrent diversionary strategy (SDDS). In an SDDS, the harvestable crop is protected by host-masking agents, repellents, antifeedants or oviposition deterrents. At the same time, aggregative semiochemicals, including host plant attractants and sex pheromones, stimulate colonisation of pests on trap crops or entry into traps where pathogens can be deployed. Because the individual components of the SDDS are not in themselves highly efficient, they do not select for resistance as strongly as conventional toxicant pesticides, thereby making the SDDS intrinsically more sustainable.