Mosquitoes transmit serious human diseases, causing millions of deaths every year and the development of resistance to chemical insecticides resulting in rebounding vectorial capacity. Plants may be alternative sources of mosquito control agents. The present study assessed the larvicidal and oviposition - deterrence activities of methanol extract of Plumbago zeylanica against the fourth instar larvae of vector mosquitoes. Larvicidal activities of LC50was studied in the range of 20 to 320 ppm in the laboratory bioassays against early 4th instar larvae of selected mosquitoes. The mortality data were subjected to probit analysis to determine the lethal concentrations (LC50 and LC90) to kill 50 and 90 per cent of the treated larvae of the respective species. Oviposition attractancy were calculated for oviposition active index and oviposition attractancy concentration which were calculated by the standard procedure. The experiments showed significant activity and larvicidal activity were tested after 24 h of exposure. The LC50 andLC90 value of Plumbago zeylanica methanol extract against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus were 47.24, 46.52, 48.28 and 94.00, 92.28 and 98.05ppm respectively. The oviposition attractancy concentration of (OAC50) Plumbago zeylanica methanol extract against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus were 55.508, 33.348 and 60.438 respectively. Our data suggest that the leaf methanol extract of Plumbago zeylanica have the potential to be used as an ecofriendly approach for the control of selected vector mosquitoes.
