Cleistopholis Patens’s Extract: An Alternative to Synthetic Insecticides against Anopheles Gambia

In this study, the toxic effects of the methanolic and aqueous extract obtained from the tree bark of Cleistopholis patens (Benth.) were evaluated against Anopheles gambiae Giles larvae and adult. Five treatment concentrations of C. patens extracts (0.1 ml, 0.2 ml, 0.3 ml, 0.4 ml, and 0.5 ml) were evaluated against A. gambiae’s larvae for contact effect and for the fumigant effect on adults. Knockdown and mortality data were obtained at intervals of 15, 30, 45, 60, 75, and 90 minutes. The result showed that 0.4 ml and 0.5 ml concentrations of the methanolic extract achieved absolute (100 %) larvae mortality at 60- and 75-minutes post-exposure. Likewise, after 90 minutes, 100% mortality was observed at 0.3 ml – 0.5 ml concentration. For aqueous extract treatments, larvae mortality recorded at 90 minutes ranged from 10 – 16.67% without significant difference (p>0.05). The high mortality of An. gambiae’s adult at 90 minutes using methanol extract was 36.67 %, while aqueous extract was 30.00 %. LC50 and LC90 recorded for methanol extract on larvae were 0.10 ml and 0.31 ml, respectively, while aqueous extract was 0.817 ml and 1.186 ml respectively. For An. gambiae’s adult, LC50 and LC90 recorded for methanol extract were 0.689 ml and 1.251 ml, respectively while aqueous extract was 1.428 ml and 2.575 ml respectively. This study suggests that aqueous and methanolic extracts of C. patens possess insecticidal activity against An. gambiae. Thus, we recommend further investigation of its component to correlate insecticidal activity with the chemical constituent.