Larvicidal efficacy of medicinal plant extracts against Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae)

Mosquitoes transmit serious human diseases, causing millions of deaths every year. Natural products of plant origin with insecticidal properties have been used in recent years for control of a variety of pest insects and vectors. The present study was based on assessments of the larvicidal activity to determine the efficacies of hexane, chloroform, ethyl acetate, acetone and methanol extracts of ten medicinal plants tested against fourth instar larvae of malaria vector, Anopheles stephensi Liston and lymphatic filariasis vector, Culex quinquefasciatus Say (Diptera: Culicidae). The larvicidal activity was assessed by the procedure of WHO with some modification. The highest larval mortality was found in leaf acetone of Adhatoda vasica, bark ethyl acetate of Annona squamosa, methanol leaf and flower of Cassia auriculata, leaf ethyl acetate of Hydrocotyle javanica, methanol leaf and seed of Solanum torvum and leaf hexane extracts of Vitex negundo against the fourth instar larvae of An. stephensi and Cx. quinquefasciatus. The calculated LC90 for acetone, ethyl acetate, methanol and hexane extracts of dried leaf and bark of A. vasica, A. squamosa, S. torvum, and V. negundo were in the range of 70.38-210.68 ppm. Our results suggest that the leaf methanol extract of S.torvum and bark ethyl acetate extract of A. squamosa from Southern India have the potential for use to control mosquitoes. Therefore, this study provides the larvicidal activity against An. stephensi and Cx. quinquefasciatus of plant extracts.