The Spatial Dimension in the Ecology of Insect Pests and Its Relevance to Pest Management

The forecast of insect population trends in the temporal dimension and the economic impact of population loads upon agricultural production was one of the central aspects of integrated pest management (IPM) during the second half of the previous century (Berryman and Pienaar 1974; Ruesink 1976; Welch et al. 1978; Getz and Gutierrez 1982; Pruess 1983; Egger 1991; Morgan and Solomon 1993). Phenological models were constructed for a vast variety of insects and crops, and used to make decisions regarding the application of control measures (Welch et al. 1981). Most of these models, however, did not take into consideration the spatial and geographic heterogeneity of the environment, a situation which may have resulted in a reduced ability of the models to forecast population trends and a lower adoption rate of the system approach for pest management (Pruess 1983; Baumgartner and Severini 1987).