Abstract

Culex mosquitoes transmit filarial worms, and current control methods heavily use chemical insecticides. Evaluating botanicals for their phyto-constituents and insecticidal properties is vital for greener and more effective mosquito vector control. We then investigated aqueous and ethanolic leaf extracts of Nicotiana tabacum and Moringa oleifera for their phyto-constituents and larvicidal effects on Culex quinquefasciatus larvae at concentrations of 1.0, 1.5, and 2.0 mg/mL over exposure times of 24, 48, and 72 h . Data were analysed using the one way analysis of variance (ANOVA), probit analysis and Chi-square tests. Phytoscreening of extracts revealed various compounds, including flavonoids, tannins, alkaloids, and glycosides. Additionally, the ethanolic extract from N. tabacum contained starch and phenols Mortality of mosquito larvae exposed to both extracts of N. tabacum varied significantly (p < 0.05); specifically at 24 and 48 h for the aqueous extracts and at 48 and 72 h for the ethanolic extracts. Similarly, for the M. oleifera extracts, significant differences (p < 0.05) in mortality were recorded only at 48 h for the aqueous and at 48 and 72 h for the ethanolic extracts. In all, highest percentage mortality occurred with the highest test concentrations (range: 86.7 – 93.3 %). The Lethal concentration 50 (LC50) values of all the plant extracts, varied significantly (F(2,9) = 101.0; p < 0.01) across exposure times: highest at 24 h and lowest at 72 h. Easy access to these plants, combined with the potency of both aqueous and ethanolic extracts, positions them as crucial tools for local mosquito vector control