505 0_ |a Part I. |t Introduction and overview. |t Introduction ; |t Beneficial insects : an overview -- Part II. |t Insects as natural enemies of plant pests. |t True bugs ; |t Lacewings and allied insects ; |t Beetles ; |t True flies ; |t Wasps and allied insects ; |t Miscellaneous predators -- Part III. |t Insects and mites as natural enemies of weeds. |t Beneficial phytophagous insects and mites -- |t Appendix I: List of parasitic and predacious insects and mites, etc., cited in Part II -- |t Appendix II: List of insects and mites cited in Part II as prey of parasites, parasitoids or predators -- |t Appendix III: List of phytophagous insects and mites associated with weeds -- |t Appendix IV: List of plants mentioned in the text.

520 __ |a Insects are key components of life on our planet, and their presence is essential for maintaining balanced terrestrial ecosystems. Without insects humans would struggle to survive, and on a world scale food production would be severely compromised. Many plants and animals depend directly or indirectly on insects for their very survival, and this is particularly so in the case of insectivorous birds and other such creatures. The beneficial role of insects is often overlooked or misunderstood, and in farming circles their very presence on crops is often seen to be unwelcome. In reality, however, many insects are genuinely beneficial, as in the case of parasitic and predacious species. The use of chemical pesticides to control crop pests is becoming more tightly regulated and environmentally undesirable, and low-input farming, in which natural enemies of pests are encouraged to survive or increase, is becoming far more prevalent. Accordingly, Integrated Pest Management (IPM) and Integrated Pest Management (ICM) strategies are increasingly being developed, advocated and adopted.