INTRODUCTION

For many years, control of tsetse fly in Africa was carried out by a variety of methods based on environmental manipulation, such as bush clearing, game exclusion, habitat destruction by burning etc. The choice of methods was mainly determined by the nature of the habitats characteristic of different species of tsetse, and also by whether the objective of these operations was tsetse control or tsetse eradication.

With the advent of the synthetic insecticide DDT and its allies, increasing emphasis has been on the application of insecticide to the tsetse environment either by means of heavy residual dosages to tsetse-resting sites, or by repeated non-residual applications at lower dosage rates (Jordan, 1974). Initially the insecticides of choice were DDT and dieldrin, the latter being favoured because of its higher toxicity to tsetse. However, it was recognised early that such tsetse control measures had a serious immediate effect on wildlife, mammals, birds, reptiles and fish (Graham, 1964). Over the last 20 years therefore, the preferred insecticide for tsetse control has been the allied organochlorine chemical, endosulphan (Thiodan) (Goebel et al., 1982) selected because of its high lethal effect on tsetse combined with less inimical effect on wildlife (Hocking et al., 1966; Park et al., 1972). That period has also been marked by operational changes; insecticides originally applied by means of ground spraying or fogging equipment, are now applied almost entirely from the air, both by fixed-wing planes and by helicopter.