ABSTRACT
Biological control sensu stricto refers to the use of one living organism to control another, the latter being a pest. However, for the purposes of this chapter we have excluded the use of the host plant (see Atkinson, Chapter 23) and largely confine our comments to the use of parasites and pathogens, which has been the subject of most research on biological control both with and of nematodes. Control organisms include a wide range of vertebrates and invertebrates and microbial pathogens, particularly fungi, bacteria and viruses. Thus, the introduction of cobras to control rats in oil palm estates in Malaysia is a method of biological control, just as is the introduction of entomopathogenic fungi to control insect pests. However, while the concept is simple, its application is not. There is no unifying model for biological control, so that the basic problem is predicting in advance where biological control will succeed and the level of control that will be obtained. This is very difficult because there is usually a great diversity of potential control agents associated with any given pest, there is a number of ways in which the agents may be used, and there is a large number of complex interactions between the animals, plants, and environmental factors that can influence success. However, when biological control is successful, the environmental and economic benefits can be immense.
