Larvicidal activity and GC-MS analysis of Leucas aspera against Aedes aegypti Anopheles stephensi and Culex quinquefasciatus

The mosquitocidal activity of aqueous, ethanol, methanol, chloroform and petroleum ether plant extracts of Leucas aspera against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus was analyzed. The larval mortality of fourth instar larvae of Ae. aegypti, An. stephensi and Cx. quinquefasciatus after 24 h and 48 h of treatment was observed separately in control 30, 40, 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500 ppm concentrations. The plant extracts were screened to identify the phytochemical bioactive compounds. Ae. aegypti was found to be most susceptible than the other species. Based on probit analysis the 24 h and 48 h methanol extracts of L. aspera showed pronounced larvicidal activity when compared with the other extracts. An LC50 and LC90 value of methanol extracts against Cx. quinquefasciatus was found to be 37.649 ppm and 27.855 ppm (24 h), 79.150 ppm and 73.284 ppm (48 h) respectively. LC50 and LC90 values were 35.624 ppm and 20.897 ppm (24 h), 64.260 ppm and 60.096 ppm (48 h) against Ae. aegypti. The 24 h and 48 h LC50 and LC90 values of ethanol extracts of L. aspera were found to be 40.877 ppm and 34.359 ppm, 72.903 ppm and 67.355 ppm against An. stephensi. The extracts of this plant showed potent larvicidal efficacy and can be considered for further investigation.