Response of <i>Culex quinquefasciatus</i> say (Diptera: Culicidae) from different larval habitats to deltamethrin and bendiocarb insecticides

Abstract

Laboratory evaluation of Bendiocarb and Deltamethrin insecticides for the management of Culex quinquefasciatus mosquitoes were conducted in June, 2016 at Arbovirus and Vectors Research Centre, Enugu, Nigeria. Cx. quinquefasciatus larvae were obtained from breeding sites (ground pools, dirty water, containers) at Michael Okpara University of Agriculture, Umudike, Southeast Nigeria. They were reared and fed with ground biscuit to adulthood. Two- to three-day old, non-blood engorged female mosquitoes were exposed separately to discriminating dosages of 0.1 % bendiocarb and 0.05 % deltamethrinimpregnated papers embedded in World Health Organisation (WHO) diagnostic test kit following their standard protocol of susceptibilities. Knockdown effect was recorded at 5 and 10 minutes intervals, and their mortality scored 24 hours after exposure. Fifty and ninety percent knockdown times (KDT₅₀ and KDT₉₀) were determined using probit analysis. The result showed that the Cx. quinquefasciatus collected from the breeding habitats were resistant to bendiocarb with a mortality of 38.50 % after 24 hours exposure. A similar result was also obtained from deltamethrin treatment with percentage mortality of 10.80. The KDT₅₀ and KDT₉₀ were 30 and 60 minutes, respectively in deltamethrin treated mosquito, whereas 40 and 60 minutes in bendiocarb treated. This result revealed that bendiocarb and deltamethrin insecticides may not be suitable alternatives to control Culex spp. at this location.

Keywords: Culex quinquefasciatus, Larval habitats, Bendiocarb, Deltamethrin, Knockdown time