Larvicidal Activity of Aqueous Pod Extract of Adansonia Digitata (Linnaeus, 1753) on Culex Quinquefasciatus (Say, 1823) Maulik

Abstract

The study evaluatrd the effect of Baobab, Adansonia digitata pod extract on larvae of Culex quinquefaciatus. The plant material was sun-dried for two weeks and pulverized using mortar and pestle and stored at room temperature for further processes. Powdered plant material was extracted using aqueous cold extraction method. The condensed extract was screened for phytochemicals. Indoor resting adult blood-fed female Culex mosquitoes were collected and introduced into Entomological Cages in the Laboratory and oviposited on water in the bowls. The third instar larvae were confirmed as Cx. quinquefasciatus using Hopkins keys for Culicinae. Triplicates of twenty-five late third instar larvae were tested in pod extract concentrations of 0.5mg/L, 1.0mg/L, 1.5mg/L, 2.0mg/L and 2.50mg/L. Mortality was recorded after 24hr of exposure. The LC50 was determined using probit analysis, while one-way ANOVA was used to establish significant differences in larval mean mortality. Phytochemical constituents such as carbohydrate, cardiac glycosides, steroids, triterpenes, tannins, flavonoids and alkaloids were present. The mean mortality of test concentrations differed significantly (p≤0.05) from control. However, the concentrations: 0.5mg/L and 8.0mg/L had 49% and 71% mortalities, respectively with LC50 of 0.6mg/L. It can be concluded that, the aqueous pod extract of Adansonia digitata demonstrated good activity against Cx. quinquefasciatus. Adansonia digitata pod extracts has potential for controlling larvae of Culex mosquitoes and can be incorporated into integrated mosquito management programme.