Local pesticide use intensity conditions landscape effects on biological pest control

Complex landscapesincluding semi-natural habitats are expected to favour natural enemies thereby enhancing natural pest biocontrol in crops. However, when considering a large number of situations, the response of natural biocontrol to landscapeproperties is globally inconsistent, a possible explanation being that local agricultural practices counteract landscapeeffects. In this study, along a crossed gradient of pesticide use intensity and landscapesimplification, we analysed the interactive effects of landscapecharacteristics and local pesticide use intensity on natural biocontrol. During 3 years, using a set of sentinel prey (weed seeds, aphids and Lepidoptera eggs), biocontrol was estimated in 80 commercial fields located in four contrasted regions in France. For all types of prey excepted weed seeds, the predation rate was influenced by interactions between landscapecharacteristics and local pesticide use intensity. Proportion of meadow and length of interface between woods and crops had a posit...