Improved understanding of dispersal in crop pest and disease management: current status and future directions

Abstract

Implementation of integrated pest management (IPM) is by definition scale- and location-specific and because these features govern biophysical processes such as dispersal, information on the latter is relevant for IPM. However, dispersal has not featured prominently as the defining and critical element of IPM schemes. At the larger regional or inter-continental scales then our understanding of dispersal has improved with the availability of new tracking technologies (e.g., Doppler weather radar, see Westbrook and Isard (1999)), but proportionate returns in terms of IPM have not been demonstrated. There is increasing interest in describing within-field and within-plant dispersal events, but much remains to be done to integrate research findings into operational IPM programmes. Models are often seen as useful tools for analysing pest and disease outbreaks and for the evaluation of alternative control options. Dispersal, in full biophysical detail, has rarely featured explicitly in such models, and indeed the lack of biological balance in complex simulation models places their uses in research, technology development or implementation somewhat in doubt. Often, however, it is possible to incorporate dispersal or more generally spatial processes into simplified models that combine applicability to real pest management situations with the insights of theoretical population ecology. Such insights are relevant to the multiple-species interactions characteristic of biological control and the ways in which dispersal affects the qualitative attributes of these interactions. Dispersal research has had a demonstrable impact on pest management and new opportunities will arise in the future.