SCREENING FOR LARVICIDAL ACTIVITY IN SOME THAI PLANTS AGAINST FOUR MOSQUITO VECTOR SPECIES

Abstract. Ninety-six ethanolic extracts from various parts of 84 Thai plant species were tested for their larvicidal activity against Aedes aegypti mosquitoes. Extracts from Rhinacanthus nasutus, Der-ris elliptica, Trigonostemon reidioides, Homalomena aromatica, Stemona tuberosa and Acorus cala-mus possessed high larvicidal activity, with LC50 values between 16.0 and 48.2 mg/l. Petroleum ether (PE) and methanol (MeOH) extracts were tested for their larvicidal activity against 4 mosquito vector species. The PE extract of R. nasutus exhibited larvicidal effects against Ae. aegypti, Culex quinquefasciatus, Anopheles dirus and Mansonia uniformis with LC50 values between 3.9 and 11.5 mg/l, while the MeOH extract gave LC50 values of between 8.1 and 14.7 mg/l. D. elliptica PE extract showed LC50 values of between 11.2 and 18.84 mg/l and the MeOH extract exhibited LC50 values between 13.2 and 45.2 mg/l