The production of winter rape is an interesting alternative to other organic cash crops: There is a high demand for organic rape oil and the culture fits very well into organic crop rotation schemes. But production is limited by different pest insects which can be hardly regulated in organic agriculture. Especially the rape pollen beetle (Meligethes aeneus) can cause total crop loss. Different studies have shown a correlation between landscape diversity and parasitism rate of M. aeneus. The question is whether the improvement of agricultural environment by sawn flower strips for the enhancement of beneficial insects and Brassica rapa catch crop can further enhance parasitoids. Aim of the current project is (1) to verify the hypothesis of correlation between landscape diversity and parasitism rate and (2) to compare the effects different strategies of additional landscape diversification and conservation biological control.
