Beneficial arthropods in arable crops.

Abstract

Since the advent of Integrated Pest Management (IPM) research has been done on the ecology and potential of pest predators in arable crops, especially cereals. Initially research concentrated on the impact of pesticides with the Boxworth Project being the most intensive study (Çilgi et al., 1993). Many beneficial arthropods were found to suffer from broad-spectrum insecticides, but the effects were insufficient to generate interest in developing an IPM system for arable crops, although they were sufficient to ensure that the impact of pesticides on beneficial arthropods became a component of the registration process. IPM systems have primarily been developed for protected crops and for crops in which insect resistance to pesticides has threatened the existing production system, e.g. cotton. However, increasing concerns over the environmental impact of pesticides, especially the indirect effects on farmland birds (Campbell et al., 1997), combined with lower grain and oilseed values is now driving arable farmers towards more integrated systems. Before an IPM system can be fully developed for arable crops the ecology of the beneficial arthropods within the agroecosystem must be understood. Much is now known of the role of beneficial arthropods in arable crops, but their contribution to pest control is difficult to quantify. This article reviews the different types of beneficial insects and spiders found in arable farmland, how they may be affected by farming practices and whether they could be manipulated to increase their contribution to pest control. The emphasis will be upon cereal crops because the majority of the European research has concentrated on this crop; less is known about predators in oilseed or legume crops.