Spatio-temporal distributions of pests and their parasitoids on the oilseed rape crop

Abstract

Good co-incidence in time and space between parasitoids and the pests they attack is essential for effective biocontrol. The six major pests of oilseed rape in Europe migrate to the crop in succession, attacking the crop at various growth stages and damaging different parts of the plant. Research on the phenologies and within-field spatial distributions of the pests and their key parasitoids on oilseed rape crops is reviewed. Pest distributions are non-uniform, with differing irregular patterns of aggregation, often edge-distributed. Parasitoid distributions do not necessarily completely reflect those of the host stage they attack. Crop and environmental factors affecting these distributions are discussed. The spatio-temporal distributions have implications for biocontrol-based integrated management of the pests. These include accurate sampling for pest monitoring, the temporal and spatial targeting of pests with insecticide to avoid killing parasitoids and strategies for manipulating pest and parasitoid distributions through the siting, layout and surround of the crop to enhance parasitoid populations and increase their effectiveness. © 2010 Springer Science+Business Media B.V.