Larvicidal efficacy of Cassia fistula Linn. leaf extract against Culex tritaeniorhynchus Giles and Anopheles subpictus Grassi (Diptera:Culicidae)

To determine the larvicidal efficacy of different solvent leaf extract of Cassia fistula (C. fistula) against Culex tritaeniorhynchus (Cx. tritaeniorhynchus) and Anopheles subpictus (An. subpictus). Twenty five early third instar of Cx. tritaeniorhynchus and An. subpictus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO 2005. The larval mortality was observed after 24 h of treatment. Among three solvent extracts tested the maximum efficacy was observed in the methanol extract. The LC50 and LC90 values of C. fistula against early third instar of Cx. tritaeniorhynchus and An. subpictus were 45.57, 33.76 ppm and 82.05, 60.63 ppm, respectively. No mortality was observed in controls. The Chi-square values were significant at P< 0.05 level. From the results it can be concluded the crude extract of C. fistula has an excellent potential for controlling Cx. tritaeniorhynchus and An. subpictus mosquito larvae.