Mosquito larvicidal potentiality of wild turmeric, <i>Curcuma aromatica</i> rhizome, extracts against Japanese Encephalitis vector <i>Culex vishnui</i> group

Abstract

Abstract:One of the promising ways to reduce mosquito population is the use of larvicide. Curcuma aromatica is a cosmetic herb in South Asia. The present study was conducted to explore the larvicidal effect of Curcuma aromatica rhizome extracts against the Culex vishnui group. To assess the larvicidal activity, crude extracts of rhizome of Curcuma aromatica were prepared ranging from 0.02% to 0.1% concentrations against all the instars of Cx. vishnui larvae. Active fractions were obtained by using six different solvents i.e. petroleum ether, n-hexane, ethyl acetate, chloroform: methanol (1:1 v/v), acetone, and absolute alcohol from non-polar to polar fashion. All the solvent extractives were tested against all the larval instars with graded concentrations ranging from 20 ppm to 100 ppm. Through log-probit analyses, LC 50 and LC 90 values were determined. Afterwards the statistical justifications were done by ANOVA analyses with reference to time, concentrations and larval instars as three entirely randomized autonomous variables. Furthermore the bioactive fraction was tested against non-target organisms under laboratory conditions. Maximum mortality was recorded in 0.1% concentrations of crude rhizome extracts against all the instars. Ethyl acetate extractives were found to have good larvicidal effect only among all the solvent extractives. The LC 50 and LC 90 values of 3 rd instars larvae were 17.25 ppm and 78.02 ppm respectively after 72 h of post exposure. The non-responsiveness of the non-target populations towards extractives was also noticed. The rhizome extracts of Curcuma aromatica can be used as an alternative larvicide against the JE vector Cx. vishnui group.

Larvicidal Potentiality of Root Extracts of <i>Annona reticulata</i> Linn. Against the Filarial Vector <i>Culex quinquefasciatus</i> Say (Diptera: Culicidae)

“…To avoid these problems, use of insecticides of plant origin are needed to control pests and vectors as plant based insecticides are easily degradable in the environment and their sources are renewable (Ilahi et al, 2012). Many researchers worked with extracts of different solvents of several plants to identify their larvicidal activity against different species of mosquitoes (Mallick et al, 2014;Singha et al, 2012;Hossain et al, 2011;Chakraborty et al, 2013;Chowdhury et al, 2008) . Methanol and butanol leaf extracts of Annona reticulata Linn.…”