Studies on insecticide-impregnated targets for the control of riverine Glossina spp. (Diptera: Glossinidae) in the sub-humid savanna zone of Nigeria

Abstract

AbstractInsecticide-impregnated blue cotton targets 70 × 110 cm weretested for the control of Glossina palpalis palpalis (Robineau-Desvoidy) and G. tachinoides Westwood in riverine fringing forests in central Nigeria, under wet-season conditions. Following exposure to treated cloth for 1·5 min, delta-methrin caused 100% mortality of G. p. palpalis for six weeks at 0·05% and for 13 weeks at 0·1%. Dieldrin at 5% was not very effective. At 4%, endosulfan initially caused a high mortality, but rapidly lost its activity, especially against females. By chemical analysis, 43% of deltamethrin applied to the fabric was found to have been lost within 12 weeks, in which 230 mm of rainfall was recorded. Placed 150 m apart in a fringing forest, targets impregnated with 0·05% deltamethrin caused a rapid decline in the G. p. palpalis population, and after 12 weeks only 5% of the original density was recorded. No further reduction or significant increase was observed during the following six months, though it appeared that flies caught during this period had immigrated from an adjacent undisturbed riverine forest. The effect on G. tachinoides was less dramatic, but this may have been due to the low initial density of this species, and to its greater mobility, giving rise to reinvasion from elsewhere.