Mosquito Larvicidal Efficacy of Andrographis echioides (Acanthaceae) Foliages Against Vector of Lymphatic Filariasis Culex quinquefasciatus Say (1823)

摘要

Increasing resistance against synthetic insecticides, mosquito control is becoming serious problem. For an alternative measure novel botanical sources can be used as good insecticides with less toxic hazards to the environment. The present study estimated larvicidal activities of Andrographis echioides against the vector of lymphatic filariasis Culex quinquefasciatus under laboratory conditions. Crude extracts of A. echioides mature leaves were examined for mosquito larvicidal activity against all the larval instars of Cx. quinquefasciatus. Solvent extraction was carried out using three different solvents viz. petroleum ether, ethyl acetate and acetone. Dose dependent larvicidal bioassays were performed using the solvent extractives. LC_(50) and LC_(90) values were consummated through log-probit analysis. Regression and ANOVA analyses were done for statistical justification. The effects of crude and solvent extractives were tested on a non-target water fauna. Crude extract of A. echioides leaf exhibited 100% mortality in 1.00% concentration against 1st instars larvae after 72 h of exposure. Among three used solvent extracts ethyl acetate showed efficient larvicidal effect against target mosquito. In ethyl acetate extractive 100.00% mortality was noticed at 150 ppm concentration against 1st instars larvae after 48 h of exposure with LC_(50) and LC_(90) values of 32.96 ppm and 106.96 ppm respectively. Tested non target organism was completely safe both from crude and ethyl acetate extractives. This experiment was a pioneer attempt to establish A. echioides as a precious resource for production of mosquito larvicide against Cx. quinquefasciatus.