The Efficacy of Cola millenii K. Schum. (Malvaceae) against Malarial Vector Anopheles stephensi (Diptera: Culicidae)

Abstract

Cola millenii (Monkey kola) is a wild plant of tropical and sub-tropical countries. The persistent increase in the incidence of antibiotic resistant strains of organisms has led to the search for newer and more potent antimicrobials. Some plant materials have traditionally been used in folk medicine, as well as in the extension of shelf-life of foods, in the case of those with antimicrobial activity. The C. millenii is such a plant, that is widely distributed throughout tropical Africa. This research investigated C. millenii leaf for its insecticidal properties against mosquitoes. The extracts of C. millenii leaf was obtained using ethanol and n-Hexane as the solvents. The insecticidal efficacy of the plant extracts were evaluated in the laboratory against larvae of Anopheles stephensi. A 40% mortality was recorded at 1 ppm of the n-hexane leaf extract, while a lethal dose that killed 50% of the test larvae was calculated as 4.18 ppm. Moreover, a mortality of 45 % was obtained at 1 ppm of the ethanol leaf extract of the plant while an LC50 of 1.71 ppm was obtained. The killing effect of the coil made from ethanol leaf extract was comparable to the commercially available coil 5 hr after exposure recording 100 % mortality in the mosquitoes. Phytocoil and phytospray were produced from the leaf extracts of the plant which gave promising results in the control of the malaria parasite vector.