In vitro repellent and larvicidal efficacy of Swietenia mahagoni against the larval forms of Culex quinquefasciatus Say

Abstract

ObjectiveTo analyze the mosquito repellency and larvicidal activity of mature leaves of Swietenia mahagoni (S. mahagoni) against Culex quinquefasciatus (Cx. quinquefasciatus) Say in laboratory bioassay. MethodsVarious concentrations of crude and petroleum ether extract of S. mahagoni mature leaves were exposed against all instars of Cx. quinquefasciatus larvae and the respective LC50, LC90, Regression equations and R values were calculated. Mosquito repellency was tested with chloroform: methanol (1:1, v/v) extract of mature leaves. ResultsCent percent mortality of 2nd instar mosquito larva was observed at 50 ppm concentration of petroleum ether extract after 72 h of exposure. 1st, 3rd and 4th instar larvae showed 96.66%, 90.00% and 60.00% mortality at 50 ppm concentration of petroleum ether respectively after 72 h of exposure. Preliminary qualitative phytochemical assay revealed the presence of saponins, alkaloids, tannin, flavonoids, and free glycoside bound anthroquinones. Chloroform: methanol extract showed repellency up to 2 h 15 min after application. No mortality was found in non target organisms, such as Gambusia affinis, Tadpole of Bufo and Chironomus larvae. Chloroform: methanol of mature leaves extract ofS. mahagoni exhibits 100% repellency upto 2 h 15 min as no mosquito bites up to that time periods in the treated hands. ConclusionsDifferent solvent extracts of mature leaves of S. mahagoni can be effectively used as a potent ecofriendly biocontrol agent against larval form ofCx. quinquefasciatus.