The potential for identifying and utilising sources of host plant resistance to the pests and pathogens of Brassica crops as a key component of future IPM strategies

Abstract: In wild species, host plant resistance is often a key factor limiting pest populations. This is not the case with most crop cultivars since they have been developed for cultivation in systems where pests, diseases and weeds have been controlled effectively by agrochemicals or other means. However, despite the widespread use of pesticides, pests and diseases and competition from weeds are still responsible for billions of pounds worth of crop losses each year. In particular, control with pesticides is confounded by factors such as loss of efficacy due to the evolution of resistance in the target species, legislative removal of products on the basis of environmental concerns, the slow development of the next generation of pesticides and limited availability to farmers in many parts of the world. Many of the problems caused by pests and pathogens could be overcome by the incorporation of genetic resistance into cultivars and this has become a major activity in most crop breeding programmes. This paper discusses, in the context of Brassica crops, the new technology and improvements in techniques which should mean that it will be ‘easier’ and quicker to incorporate new traits for pest and disease resistance into commercial crop cultivars. It suggests that possibly one of the greatest bottlenecks in the process at the moment is the lack of resources for ‘phenotyping’ – screening plant material for useful traits.