Considerations in the design of a field trial for tsetse fly control

has been a scourge across the middle of the continent of Africa for centuries. A blood-sucking insect, it feeds generally on warm-blooded animals, principally larger wild game, domestic livestock, and man. The fly serves as an intermediate host for the trypanosome which causes the illnesses known as sleeping sickness in man and nagana in domestic livestock; many wild animals have developed immunity to the effects of the trypanosome. The illness causes a general wasting away and lethargy in both man and domestic livestock, often resulting in death. Finding an appropriate method for control of the tsetse fly would have great economic importance in Central Africa. This study deals with examination of a proposed field test in Tanzania to demonstrate control of one species of the tsetse fly, Glossina morsitans, by the sterile insect techniques (SIT). The technique involves flooding a land area with a dominating number of sterile male flies whose matings with fertile females will produce no progeny. Theoretically, over time, with sufficient release of sterile males, the population of indigenous flies should reduce to nearly zero. If feasible economically and biologically, this kind of insect control represents an ideal control technique.