Larvicidal Activity of Aqeous Extract of <i>Moringa oleifera</i> Seeds on <i>Anopheles gambiae</i> and its Effects on <i>Poecilia reticulata</i>

Abstract

Malaria is a major public health problem and its prevalence is dependent on mosquitoes. There is an increased interest in developing plant-based insecticides as sustainable alternatives to chemical insecticides for the control of mosquitoes. The potential of Moringa plant as a larvicide against the malaria vector, Anopheles gambiaes. S was evaluated and its effects on mosquito fish were also studied. Toxic components in Moringa oleifera seeds were extracted using; five aliquots of concentrations ranging from 1160-8700 μg/ml were prepared by serial dilutions from the extract. Three independent laboratory procedures were run in quadruplicate in which third instar larvae of Anopheles gambiaes. S was exposed to different concentrations and a control group was exposed to distilled water. The fishes were exposed to three graded treatment of the aqueous extract in two experiments run in triplicate. Behavioral changes were observed for 24 hours. From the larval bioassay, the extract presented a 72hour- LC50 and LC90 of 1885.4 μg/ml, 3902.4 μg/ml respectively, (p<0.05), causing 99.33±1.15%mortality at 8700μg/ml. The toxicity assay showed that the guppy fishes exhibited varying degrees of changes as a result of the exposure to treatment unlike in the control. The results obtained show that Moringa seed extract has larvicidal potentials for Anopheles gambiaes. S with observed little or no toxicity effects on the non target, guppy fish. The effectiveness of Moringa seed extract makes it a viable larvicide. Moringa-based larvicides may provide cheap and readily available alternative to synthetic insecticides.

Keywords: Malaria, mosquito control, Guppy fish, Larvicidal activity, Moringa oleifera seeds.