Toxic and biological effects of Moringa oleifera Lam. crude seed extract againstCulex pipiens L. (Diptera; Culicidae) larvae

Abstract

Mosquitos resistance to chemical insecticides motivated the need for alternative control strategy. Therefore, botanical extracts have become one of the control revolutionary methods in the sustainable vector strategy. Current study was conducted under laboratory conditions to evaluate the toxicological efficacy of the crude seed extract of Moringa oleifera against the 3rd larval instar of Culex pipiens mosquito. A series of aqueous concentrations had been prepared (100, 80, 60, 40 and 20 ppm) to carry out the laboratory bio-assay experiment. The highest larval mortality took place at 100 ppm concentration (81.39%). LC50 and LC90 values of M. oleifera seed extract recorded 67.91 ppm and 144.63 ppm after 120 hr exposure time, respectively. The obtained data revealed that larvicidal effect, malformed feature incidence and the cumulative larval death percentages were of time and concentration dependent manner. Similar trend had been documented for the total death percentages of both pupal and adult stages. On the contrary, the percentages of viable pupation and the emerged mosquito showed reverse responses. Accordingly, Moringa extract could be considered as a promising non-chemical candidate in the IPM programs of Culex mosquito.