Epidemiology of insect-transmitted plant viruses: modelling disease dynamics and control interventions

Plant viruses are an important constraint to crop production world-wide. Rarely have plant virologists, vector entomologists and crop specialists worked together in search of sustainable management practices for viral diseases. Historically, modelling approaches have been vector-based dealing with empirical forecasting systems or simulation of vector population dynamics. More recently, epidemiological models, such as those used in human/animal epidemiology, have been introduced in an attempt to characterize and analyse the population ecology of viral diseases. The theoretical bases for these models and their use in evaluating control strategies in terms of the interactions between host, virus and vector are considered here. Vector activity and behaviour, especially in relation to virus transmission, are important determinants of the rate and extent of epidemic development. The applicability and flexibility of these models are illustrated by reference to specific case studies, including the increasing importance of whitefly-transmitted viruses. Some outstanding research and methodological issues are considered.