Larvicidal Activity Validation of Scorodophleous zenkeri Harms and Garcinia mangostana L. from Democratic Republic of the Congo using Culex quinquefasciatus (Diptera: Culicidae) as model system

Abstract

The emergence of mosquitos' resistance to synthetic insecticides constitutes a public health challenge in endemic areas. Insecticides of plant origin may serve as an alternative bio-control technique. The aim of this study was to evaluate the bioactivity of aqueous extracts of G. mangostana and S. zenkeri on Cx. quinquefasciatus larva. Larvicidal bioassays were carried out according to WHO protocol. The results showed that S. zenkeri is more larvicidal than G. mangostana. Aqueous extract of S. zenkeri displayed a very good larvicidal activity than G. mangostana with 90% mortality rate at 50% of extract dose after 24 hours exposure (LC50= 32.5 ± 5.8 mg/l and LC90= 47.7 ± 6.2 mg/l). The present finding indicates that selection of plant through zoopharmacognosy approach can serve as source of promising botanical mosquito control agents (which are biodegrade and environmentally no persistent) to be proposed as alternative to the conventional larvicides. For the best of our knowledge, this is the first report on the larvicidal activity of S. zenkeri from Democratic Republic of the Congo in the literature using Culex quinquefasciatus as model system.