Das Projekt "Effects of plant density and host plant architecture on abundance and level of parasitism of stem boring pests in oilseed rape" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Department für Nutzpflanzenwissenschaften, DNPW Abteilung Agrarpedologie durchgeführt. The work focuses on the oilseed rape stem-boring pests cabbage stem flea beetle (Psylliodes chrysocephala), rape stem weevil (Ceutorhynchus napi) and cabbage stem weevil (Ceutorhynchus pallidactylus) and their parasitoids. Different plant densities influence among other things plant size, stem diameter and the number of lateral racemes. The effects of these host plant factors on the abundance and within-plant distribution of the larvae of the above mentioned pests is examined. The level of parasitism referring to the within-plant distribution of the larvae and the larval instars is detected. Furthermore an analysis of the chemical cues for the host finding behaviour of the parasitoids is made. The project is part of the MASTER-program (Management Strategies for European Rape Pests). In this program integrated pest management strategies incorporating bio-control for oilseed rape pests are tested.