Biological control of insect pests
Natural enemies of insect pests play a key role in reducing the levels of pest populations below those causing economic injury. Both natural and applied biological control tactics are important in successful management of pest populations. Bi- ological control has the advantage of being self perpetuating once established and usually does not harm non-target organ isms found in the environment. In addition, it is non-polluting or as disruptive to the environment as chemical pesticides, nor does it leave residues on food, a concern of many people today. However, the use of biological control does require detailed knowledge of the pest's biology and the natural enemies associated with the pest and their impact. Many biological agents have been used for the biocontrol of insect pests, but only bacteria and fungi are most impor- tant. Bacteria used for biological control infect insects via their digestive tracts. Bacillus thuringiemsis is the most widely applied species of bacteria used for biological con- trol of lepidopteran(moth, butterfly), coleopteran(beetle) and dipteran(true flies, Frederick and Caesar 2000) Fungi that cause disease or infection in insects are known as entomopathogenic fungi, including at least 14 species of fungi attack aphids. Species of the entomophthoraceous genus Trichoderma are used to manage some soil-borne plant pathogens. Beauveria bassiana is used to manage