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SUSCEPTIBILITY OF Aedes aegypti PUPAE TO NEEM SEED KERNEL EXTRACTS
Authors: UMAR, Abba, KELA, Santa Larit and OGIDI, Jonathan Asadabe
Number of views: 45
Laboratory bioassays were conducted to evaluate the pupicidal activity of neem (Azadirachta indica) seed kernel extracts (NSKE) on Aedes aegypti. The neem seed kernel powder was sequentially extracted with hexane, benzene, ethyl acetate, acetone, DMSO, 2-propanol, ethanol, methanol and distilled water. Ten concentrations (0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 50, 10.0,15.0 and 20.0%) of the neem extracts were used for the bioassays. Each treatment was replicated five times. Twenty-laboratory strains of Aedes aegypti pupae were exposed to each concentration Pupae were not fed during the exposure periods. Pupal mortality was assessed after 1 and 24 hours of exposure. The results of the effects of 1h exposure indicated decreased pupicidal mortality with decreasing extracts toxicity thus: ethyl acetate (LC 50 = 0.06%) > acetone > (LC50 = 0.29%) > benzene (LC50 = 0.82%) > hexane (LC50 = 3.13%) and propanol (LC50 = 763%). No pupal mortality was observed with extracts from Dimethyl sulfoxide (DMSO), ethanol, methanol and distilled water. The results of the effect of extract for 24h exposure indicated pupicidal mortality in2-propanol (LC50 = 0.67%) and ethanol (LC50 = 1.70%). No pupcida mortality was observed with hexane, benzene, ethyl acetate, acetone, Dimethylsulfoxide (DMSO), methanol and distilled water extracts. The ability of some neem extracts to kill Aedes pupae at relatively low concentrations presents an alternative to the use of synthetic pesticides for the control of mosquitoes. This technique is environmentally friendly, biodegradable, less expensive, and locally available in mosquito endemic areas. Potentials for adoption in mosquito management programmes cannot be overemphasized.