Role of behavioural studies in the development of management strategies for forest insect pests

Abstract

Under forestry conditions, management techniques aimed at maintenance of pest populations at moderate levels have greater chance of success than conventional methods of pest control. Simple behavioural observations can sometimes be used to great advantage in the development of such methods, some examples of which are given. Although there has been considerable excitement over the past two decades on the possibility of using behaviour modifying chemicals for control of pests through mass trapping or disruption of the insect’s normal communication systems, no significant practical achievement has so far been reported. Difficulties in the use of these chemicals include inadequate information on the biological responses of natural populations of insects; utilization by most insects of a complex pheromone system involving several chemical components; non-reproducibility of laboratory results under natural conditions due to several modifying factors; high cost of the development and deployment of pheromonal control systems, particularly for low value forestry crops; inadequacy of pheromonal control methods for coping with the high epidemic densities of most forest pests; and the possibility of development of pheromone resistance. Behaviour-modifying chemicals, such as food lures, sex pheromones and population aggregating pheromones, however, are useful in pest management as tools for survey and ecological research. Populations generally exhibit properties that cannot be understood by studying individual insects; study of the behaviour of populations is therefore more important than study of the behaviour of individuals for developing management strategies.