Mosquito Larvicidal Efficacy of Michelia champaca Seed Extracts Against Culex vishnui

Abstract: The purpose of the study is to evaluate the larvicidal effectiveness of solvent-based seed extracts from Michelia champaca against the Japanese encephalitis causing rice field mosquito, Culex vishnui. The methanolic extract obtained from Michelia champaca seeds showed potent larvicidal effect. With a regression coefficient value close to 1 in each instance, the rate of mortality was positively correlated with the increasing concentrations of solvent extracts, indicating a clear positive dose-dependent mortality. For the extractive, the lowest LC50 and LC90 values was exhibited to be 63 ppm and 114 ppm, respectively against second instar larvae after 72 hours of exposure in a larvicidal bioassay. For chemical profiling of the methanolic extractive, FT-IR analysis was relied upon. Non target organisms such as Chironomous sp. and Diplonychus sp. were marked safe upon treatment with solvent extract. Keywords: Culex vishnui, FT-IR analysis, Japanese encephalitis, LC50 and LC90, Michelia champaca