Biodiversity and integrated pest management in agroecosystems
农田生物多样性与害虫综合治理

In modern agroecosystems, natural plant communities are usually modified to meet the special needs of humans with a specific species of cultivated crop over vast area, and other species of plants are artificially excluded for improving the crop yield. The instability of agroecosystems, which is manifested as worsening of most insect pest problems, is increasingly linked to the expansion of crop monocultures in place of the natural vegetation, thereby reduction of species and habitat diversity in the fields. Agricultural biodiversity may be affected by many factors, such as geographical location, climatic types, environmental variables, crop varieties, interspecific relations and cultivated activities, etc. Based on current ecological principles and research results, higher natural enemy and lower insect pest potentials can be expected through restoration and enhancement of the agricultural biodiversity which may be well done in the manners of rational arrangement of mixing crops in time and space, discontinuity of monoculture in time through rotation, ground cover vegetation in perennial crop systems, high genetic diversity using variety mixtures, and so on. In the planning for a biodiversity management strategy in agroecosystems, however, local variations in climate, geography, vegetation, crop and soil must be taken into account because these variables might increase or decrease the potential for pest development under certain habitat conditions.