A trial of a cypermethrin ‘pour-on’ insecticide to control<i>Glossina pallidipes, G. fuscipes fuscipes</i>and<i>G. morsitans submorsitans</i>(Diptera: Glossinidae) in south-west Ethiopia

Abstract

Abstract Tsetse populations and trypanosome prevalence in cattle were monitored from 1986 to 1993 in the Ghibe valley, south-west Ethiopia. From January 1991 to December 1993 between 2000 and 4000 cattle were treated at monthly intervals with a synthetic pyrethroid insecticide, cypermethrin (RS-alpha-cyano-3-phenoxy- benzyl [1RS]- cis, trans -3-[2,2-dichlorovinyl]-2,2-dimethylcyclopropane carboxylate). An approximate dosage of 1 ml per 10 kg bodyweight was used to control tsetse flies ( Glossina spp.). Treatments were given as ‘pour-on’ applications along the backlines of animals, using automatic drench-gun applicators. This resulted in a decline of 93% in the apparent density of G. pallidipes Austen. A reduction of 83% in the apparent density of G. morsitans submorsitans Newstead was also observed. This reduction was associated with a reduction in trypanosome prevalence in cattle of over 74% in 1993, despite a high level of resistance to all available trypanocidal drugs. The numbers of Stomoxys spp. (Diptera: Muscidae) and Tabanidae were also significantly reduced (P &lt; 0.01).