Organic Control of Oilseed Rape Pests through Natural Pesticides and Mixed Cultivation with Turnip Rape

A mixed cropping system of rapeseed and 10 % turnip rape as trap crop was compared with oilseed rape in pure stand to demonstrate the reduction of infestation by insect pests. Furthermore the application of bio-pesticides like pyrethrum/rape oil (Spruzit® Neu), spinosad (SpinTor), diatomeen earth (SiO~2~) /sunflower-oil and rock powder/water was tested. Oilseed rape showed a higher infestation by stem weevils (_Ceutorhynchus_ spp.) in the mixed cropping system compared to rapeseed in pure stand. The reduction of the pollen beetle (_Meligethes aeneus_) on the rapeseed buds resulted from higher attractiveness of turnip rape as a consequence of advanced growth. The faster development of turnip rape seems to be the important key of successful pollen beetle regulation. The application of pyrethrum and spinosad against _Ceutorhynchus_ spp. had no effect, spinosad was the only agent that caused a reduction of the pollen beetle