Integrated crop and pest management of winter oilseed rape (Brassica napus L.)

The six major pests of winter rape in Europe: cabbage stem flea beetle (Psylliodes chrysocephala), cabbage stem weevil (Ceutorhynchus pallidactylus), rape stem weevil (C. napi), pollen beetle (Meligethes spp.), cabbage seed weevil (C. obstrictus) and brassica pod midge (Dasineura brassicae) are partly, sometimes fully, controlled by natural enemies. Crop management can either support or counteract this natural control. An objective of this European Union project No. QLK5-CT-2001-01447 was to design and test an Integrated Crop Management (ICM) system that aimed to be energy-efficient and high-yielding, giving a good economic net return yet with high natural control of pests and to compare it with a standard STaNdard (STN) farming system aimed to depict a modern way of growing rape. The two systems were compared in joint experiments in five countries. Non-inversion tillage was used to increase parasitisation of pollen beetle and seed weevil and activity-densities of ground beetles. Schedule spraying gave more control of stem weevil larvae than spraying to-control thresholds. Differences in yield between the two systems were generally small. Where control thresholds were used, pesticide use was more than halved. Cost of soil tillage and the seed yield achieved were the main factors determining net return. Embedded energy of nitrogen fertiliser was more important than energy used for soil tillage. In the ICM system, total production costs, total energy use, labour and fuel costs were lower despite the need for one additional herbicide treatment; however, energy efficiency and nitrogen utilisation was a little lower indicating a need to better adjust nitrogen supply to yield level. A fanning system based on the principles of ICM with non-inversion cultivation of soil can be recommended to farmers as a strategy to improve natural control of economically-important pests of winter oilseed rape, usually increase net return, decrease environmental impact and use less resources.