ABSTRACT
The results of a project whose objective was to eradicate Glossina palpalis palpalis from a 1500 km2 area in central Nigeria are reported. The project (BICOT) was conducted by a team of scientists including Nigerians and expatriates in Nigeria and by scientists from the tsetse unit of the International Atomic Energy Agency, Seibersdorf Laboratory, Austria. Within the project area, there was a total of 450 linear kilometers of gallery forest. Prior to the release of sterile Insects, the wild tsetse population was reduced by more than 90 % with biconical traps. Sterile male flies for field release were produced by a mass-rearing facility in Vom, 200 km from the release area. Both in vivo and in vitro feeding techniques were used. Male flies destined for release were colour marked, irradiated at 12 k-Rad in a Co-60 source and allowed to feed on guinea pigs, before being packed and shipped to the release area. These were released in the target area, approximately 150 sterile flies per week per linear kilometer of gallery forest. A sterile to wild male ratio of 3:1 was expected to lead to eradication, but when this proved ineffective, the ratio was increased. At the 10:1 ratio, eradication of G. p. palpalis was reached within 6–12 months. The impact of the sterile males on the wild population was studied by examination of the female reproductive organs, and confirmed by high levels of induced sterility. The eradication area was protected from reinvasion by the use of insecticide impregnated targets, which had been placed alongside streams surrounding the area, at 50 m intervals over a length of 10 linear kilometers. At the time of writing (January 1986) 60 % of the area had been freed of G. p. palpalis using the SIT, while eradication in the remaining area was in progress.
