Managment of Crops to Prevent Pest Outbreaks

Organic farmers face the same potentially severe pest problems as their colleagues in integrated pest management (IPM) and conventional farming systems. However, approaches to manage the pest insects are different because the aim of organic farming is a holistic system perspective rather than simple reductionist control approaches. Organic cropping systems are designed to prevent damaging levels of pests, thus minimizing the need for direct and curative pest control (Peacock and Norton, 1990). Within the following chapter, we will briefly explain the standards for organic farming, which also set the framework for pest control. We present a conceptual model for pest control in organic farming and describe the influence of functional agro-biodiversity and conservation biological control on pest management. We focus on the use of preventive strategies and cultural control methods. The system approach is illustrated with examples in organic Brassica vegetable and oilseed rape production, because these economically important crops (Ahuja et al., 2010) are attacked by a broad range of different pest insects (Ahuja et al., 2010; Smukler et al., 2008) and show different levels of tolerance. Economic thresholds for pests on oilseed rape are usually higher than on vegetables. Therefore, less control is used in oilseed rape which might lead to the build-up of large pest populations, threatening nearby vegetable fields. With the increasing surface of oilseed rape production, pest problems in these crops are likely to increase