Introduction

One of the oldest methods of pest control is the use of other animals as carnivores to reduce pest numbers. More recently other biological organisms, such as microbes causing insect diseases, plants which are resistant to pest attack and animals that tolerate, at least to a certain extent, infection with diseases, have been used for pest and disease control. These are discussed in succeeding chapters, while ‘biological control’ in this chapter is limited to the use of animals that are natural enemies of insects. There are no elementary recent texts on biological control; the slim volume by Samways (1981) can still be recommended. An excellent recent book, but an advanced text (more than 500 pages), is that by Van Driesche and Bellows (1996).

History of biological control

The use of biological control is probably about as old as the history of agriculture. Chinese cave paintings clearly show ducks being used to consume pests at the base of plants in rice paddies, a technique still in use in China today. However, the first well documented case of biological control occurred in 1762, when a Mynah bird (Gracula religiosa) was brought from India to Mauritius to consume locusts. In the 1770s, the practice developed in Myanmar (Burma) of creating bamboo runways between citrus trees to enable ants to move between the trees more freely for the control of caterpillars.