Comparative study on larvicidal potentials of Cymbopogon citratus stapf, Ricinus communis L. and Allium sativum L. on fourth instar larvae of Anopheles mosquitoes

Abstract

Abstract Background The war against malaria in Africa especially Sub-Saharan Africa seems to be unending despite all efforts being invested on it for some decades. Mosquitoes have remained key transmitters of malaria. This study evaluated the larvicidal potentials of ethanolic leaf extracts of Cymbopogon citratus, Ricinus communis and Allium sativum on the fourth instar larvae of Anopheles mosquito. Results Cymbopogon citratus had the highest mortality of 78% (312) out of 400 larvae used in all the varied concentrations (100, 200, 300, 400 and 500 mg/l), and had the least LC50 value of 54.08 mg/l. Ricinus communis and Allium sativum had mortalities of 59.75% (239) and 73.75% (295) with LC50 of 141.25 mg/l and 81.096 mg/l, respectively. There was no mortality in the control. Temperature, pH and conductivity correlated positively with mortality (p < 0.05) while dissolved oxygen and total dissolved solids did not positively correlate with mortality (p > 0.05). Conclusions Ethanolic leaf extracts of Cymbopogon citratus, A. sativum and R. communis have larvicidal properties. However, C. citratus was most effective followed by A. sativum while R. communis was the least effective. The extracts of these plants can serve as replacements to synthetic insecticides because they are bio-degradable, ecologically friendly, safe for non-target organisms and do not lead to an aftermath problem and still have properties that can reduce pest populations.