The collapse of Glossina tachinoides populations, within a 27-month period of weekly sampling by means of unbaited biconical traps, in two peridomestic agroecosystems is described. Consistent removal of parous flies through trapping and low recruitment of young flies into the population, were largely responsible for unabated decline in the apparent density of both G. tachinoides populations. Reduction in the size of the resident pig population to below five pigs/week/agroecosystem triggered the collapse of both tsetse populations. Some ecological implications of these findings and their possible application in tsetse control are discussed.

The combination of a trapping system of insecticide impregnated screens and biconical traps followed by the release of sterile males led to the complete control of Glossina palpalis gambiensis and Glossina tachinoides in the agro-pastoral zone of Sideradougou. This area, situated south of Bobo Dioulasso, Upper Volta, in the Guinea savannah, covers an area of approx. 3000 km2. Along more than 650 km of rivers, bordered by gallery forests and infested by riverine tsetse, 6500 impregnated screens were placed during 4 months of the dry season, followed by the release of sterile males in the rainy season. For release purposes, colonies of 150,000 producing females of G.p. gambiensis and 85,000 females of G. tachinoides were maintained in industrial colonies on artificial membranes. Reinvasion of the project area was prevented by two barriers consisting of biconical traps impregnated with synthetic pyrethroid in one and simple biconical capture traps in the other. The screens reduced the initial fly population by 94% and permitted the release of only 35 sterile males per km of river to attain the planned ratio of seven sterile males to one wild male. Regular surveys showed that, after 4 months of release of sterile males, the relic fly population was constantly decreasing and tending towards disappearance.

An economic evaluation based on the production costs of the sterile males together with the costs of field operations showed that this combination of two non-pollutant methods was competitive with other methods of tsetse control.