Larvicidal Efficacy of Crude Seed Extracts of Six Important Oil Yielding Plants of North East India against the Mosquitoes Aedes aegypti and Culex quinquefasciatus

Abstract

The use of botanicals as an alternative to the chemical compounds is gaining tremendous momentum because of its multifarious advantages. In view of its increasing interest, an attempt was made in the present study to assess the larvicidal potential of a few plants like Pongamia pinnata, Azadirachta indica, Croton tiglium, Cascabela thevetia, Ricinus communis and Datura stramonium against two medically important mosquito vectors Aedes aegypti and Culex quinquefasciatus. The late third and fourth instars larvae were exposed to different concentration (i.e. 25, 50, 100, 250, 500, 1000 ppm) of crude oil extracts of seeds of all the six plants. The seed extracts of P. pinnata showed highest larvicidal activity with LC 50 value of 18.35 ppm and 26.21 ppm against the larvae of Ae. aegypti and C. quinque fasciatus respectively. Crude seed oil of Azadirachta indica, Croton tiglium, Cascabela thevetia, Ricinus communis and Datura stramonium also having moderate larvicidal potency with LC 50 value of 23.64, 82.08, 95.19, 80.83 & 88.69 ppm against Ae. aegypti and 54.77, 104.38, 140.99, 113.22 & 92.12 ppm against C. quinquefasciatus. These results suggest that the crude seed extracts of all the six plants might be considered promising as larvicide against both the targeted mosquitoes. It may be projected that considering the wide distribution and availability of these trees in this N.E. region of India, this may be developed and used as readily available and cheap natural insecticides for mosquito control.