Efficacy of two tropical plant extracts for the control of mosquitoes

Abstract

The larvicidal activity of seed and leaf extracts of Calophyllum inophyllum and leaf extract of Rhinacanthus nasutus on the juveniles of Culex quinquefasciatus , Anopheles stephensi and Aedes aegypti was determined. Ethyl acetate (EA) soluble fractions of C. inophyllum and petroleum ether (PE) fraction of R. nasutus extracts showed very high larvicidal activity. Irrespective of the species of the mosquitoes tested, at concentrations ranging from 3.91 to 9.39 ppm, 9.04 to 35.49 ppm and 13.21 to 28.92 ppm of the active fractions of seed and leaf extracts of C. inophyllum and the leaf extract of R. nasutus , respectively, killed 50% of the treated larvae. The fractions also interfered with adult emergence. Exposure of the mosquitoes at any stage of their larval development to less than 0.86, 5.49 and 6.81 ppm of the active fractions of seed and leaf extracts of C. inophyllum and the leaf extract of R. nasutus , respectively, inhibited 50% of the treated larvae from emerging as adults. Experiments under laboratory and semi‐field conditions showed that the activity of the extracts persisted for up to 10 days.