LABORATORY EVALUATION OF SOME PLANT EXTRACTS AGAINST THE LARVAE OF TWO MOSQUITO SPECIES (DIPTERA: CULICIDAE)

Abstract

Laboratory experiments were conducted at the insectary of the Khartoum Malaria Free Initiative to evaluate the larvicidal activity of ethanol extracts from leaves of three plants: castor bean plant (Ricinus communis), vinca (Vinca rosea) and lantana (Lantana camara) against the 3rd instar larvae of the two main mosquito vectors of malaria and lymphatic filariasis in Sudan Anopheles arabiensis and Culex quinquefasciatus respectively. All concentrations of the plant extracts and those of Temephos were prepared according to the standards of the WHO recommendations for susceptibilities tests. The dead larvae were recorded after 24 hours and the percentages mortality were calculated. The larvicidal activity of each plant extract was compared with the standard larvicide Temephos (Abate®). Larvae of A. arabiensis were found more susceptible to all the plant extracts and the standard Temephos compared to C. quinquefasciatus larvae. Results indicated that castor extract had the greatest larvicidal effect against A. arabiensis and C. quinquefasciatus larvae with the lowest LC50 = 282.7060 ppm and 323.0354 ppm, respectively when compared to other plant extracts, followed by vinca and lantana respectively. ‫.‪species, with LD50s of 0.0013 and 0.0052 ppm for A. arabiensis and C‬‬ ‫.‪quinquefasciatus larvae respectively‬‬ ‫‪This study suggests that the leaf extracts of the three plant species are‬‬ ‫.‪promising as larvicides against A. arabiensis and C. quinquefasciatus‬‬