Susceptibility test of female anopheles mosquitoes to ten insecticides for indoor residual spraying (IRS) baseline data collection in Northeastern Nigeria

Lambdacyhalothrin (0.05%), Malathion (5%), Permethrin (0.75%), Propoxur (0.01%), Alpha-cypermethrin (0.75%), Bendiocarb (0.1%), Bifenthrin (0.15%) and untreated (control). Twenty (20) two to three day-old, female Anopheles species, glucose fed, none blood fed, were exclusively used in the bioassay per treatments which was replicated three times. The post exposure 1 h knockdown and 24 h mortality was assessed. The results of the knockdown assessment indicate that Alphacypermethrin had the lowest KD50 (time taken to knockdown fifty percent of the exposed mosquitoes) value of 4.8 min. Relatively moderate KD50 values (minutes) were obtained with Propoxur (11.34), Deltamethrin (13.20), Malathion (15.82), Bendiocarb (17.29), Permethrin (18.43), Cyfluthrin (20.28) and Lambdacyhalothrin (23.11). Relatively higher KD50 values were obtained with Bifenthrin (27.29) and DDT (32.12) impregnated papers. The results of mortality assessment indicate that Anopheles mosquitoes were susceptible to Alphacypermethrin, Malathion and Propoxur with 100% mortality. The Anopheles species were less susceptible to Bifenthrin, Lambdacyhalothrin, Permethrin, Deltamethrin, Bendiocarb, Cyfluthrin and DDT. The Anopheles species used in the tests were morphological identified as Anopheles gambiae, Anopheles funestus and Anopheles nili. The public health significance of these findings is discussed.