Larvacidal effects of methanolic and ethanolic leaf extracts of Xienemia americana against female Anopheles gambiae S.L. (Culicidae: Diptera)

Abstract

Anopheles gambiae complex is the most important vector of malaria in sub-Saharan Africa. It is thought that Nigeria comprises about 45 species of Anopheles mosquitoes of which Anopheles gambiae is the most prevalent. Extract of different concentrations were evaluated at the level of 2.00 3.00, 4.00, 5.00 and 0.00 (Control) mg/ml. Distilled water only was used as control. Twenty (20) larvae were put into four (4) cups containing 100ml of the test solution of each concentration. Larval to pupa mortality were recorded and calculated after 24, 48 and 72h after treatment. Mortality results were used to determine LC₅₀ and LC₉₀ using probit analysis. The larvicidal activity of methanol and Ethanolic extracts of the X. Americana were evaluated on 4th instar larvae of Anopheles gambiae. From the results concentration of X. americana with ethanol has shown high larvicidal effect with 10%, 12%, 3% adult emergence when compare with control. While Methanol concentration reveals low larvicidal effect with 16 % adult emergence. Treatment group X. Americana showed highest survival from pupa to adult (28, 18% and 6%) recorded, this means concentration of ethanol has larvicidal effect against A. gambiae. However, methanol concentration shows low activity with 45, 21 and 16% followed by X. Americana with 18, 15 and 10% recorded the highest larvicidal activity among all the concentrations with methanol respectively. Concentration of 5.0 mL, 12.0 mL, 20.0 mL, 25.0, 30.0mL compare to control group. All the extracts proved to be toxic to the test organism, though there was a remarkable difference in the concentrations and timing of their activity.