This unit deals with the basic biology, ecology and management of pest organisms (insects, diseases and weeds) which attack plants in agricultural and environmental ecosystems. The principles of ecological, physical, biological and chemical control techniques are discussed, and the concepts of integrated pest management are applied. Topics include: the main groups of plant pests and their economic impacts, economic thresholds, identification, biology and ecology; mode of action, application and detoxification of pesticides; management of pesticide resistance; biological control using natural enemies; pest management through environmental modification; use of resistant varieties including transgenic plants; quarantine; and integrated pest management systems.