ABSTRACT
Strategies for pest management often assume that pest populations are more or less static. Numbers of insects or intensity of disease within a crop may be monitored, sometimes routinely, and emergency action taken when a certain threshold is exceeded. But pest organisms can be highly mobile, with individuals traveling many kilometers before causing harm, such as crop yield reduction or illness in humans and livestock through transmission of disease organisms. Such mobility adds to the difficulties of management, but it also provides opportunities for alternative management strategies: monitoring and controlling pests at their source or during movement (preventive strategies) as well as in the area at risk (defensive strategies). Study of pest mobility is particularly justified if it can lead to a reduction in (a) spread of harm, particularly that caused by an influx of a new genotype, and (b) waste, such as field monitoring or application of management techniques at wrong times or places.
