Evaluation of lavicidal efficacy of seed extract of Azadirachta indica in laboratory bioassay on Anopheles mosquitoes

Abstract

Azadirachta indica extracts (ethanol and aqueous) were tested against the 2nd and 3rd instar larvae of Anopheles mosquitoes. Anopheles mosquito were collected from possible breeding sites such as the puddles, tires tracks, rice fields, gutters etc. around Mubi town. Probit analysis was used to determine the lethal concentration of the extracts at 50% and 95% i.e. LC50 and LC95, respectively. The result of the laboratory bioassay revealed that A. indica extracts at 50, 100 and 200 mg/ml significantly (P>0.05) controlled larval Anopheles mosquitoes in Mubi. However, ethanol extract proved to be more potent than aqueous extract as 100% mortality was recorded after 24 hours in all its concentrations, compared to aqueous extract, where mortality was spread between 24 hours and 48 hours. The LC50 and LC95 further proved the superiority of ethanol extract over aqueous extract. LC50 (-12.309) and LC95 (3.589) calculated for ethanol extract was significantly lower compared to LC50 (2.24E+08) and LC95 (1.08E+09) recorded for aqueous extract. Therefore, A. indica is a promising phytochemical which can be used sustainably as an alternative for chemical insecticide in controlling mosquitoes.