Evaluation of the insecticidal activity of the methanol extracts of Calotropis procera (Asclepiadaceae) and Albizia lebbeck (Mimosaceae) on larvae of Culex quinquefasciatus Say, 1823

Abstract

Vector-borne diseases are mostly transmitted by mosquitoes. Therefore, these mosquitoes constitute a socio-economic scourge. Due to the resistance of mosquitoes to synthetic chemical insecticides and the pollution they generate, this study was conducted to assess the larvicidal activity of plant crude extracts on larvae of Culex quinquefasciatus. Bioassays performed on larvae shown that the extract of Calotropis procera at 0.6 mg/mL recorded the highest mortality rate of 100% for L1, L2 and L3. However, the extract of Albizia lebbeck at 0.7 mg/mL recorded the highest mortality rate of 100% for all the four stages of larvae. Negative and positive controls recorded 16% and 100% mortalities, respectively, after 24 h of exposure. The extract of Calotropis procera recorded LC50 values as follows: 0.194, 0.251, 0.258 and 0.284 mg/mL for L1, L2, L3 and L4, respectively. The LC90 of Calotropis procera were: 0.340, 0.433, 0.444 and 0.502 mg/mL for L1, L2, L3 and L4, respectively. In contrast, the extract of Albizia lebbeck recorded the following LC50: 0.238, 0.264, 0.290 and 0.316 mg/mL for L1, L2, L3 and L4, respectively. Also, its LC90 were: 0.456, 0.498, 0.531 and 0.580 mg/mL, respectively, to L1, L2, L3 and L4. The larvicidal bioassays performed revealed that these plant extracts have significant larvicidal properties. In the framework of fighting against vector-borne diseases, these two plants constitute alternative products to control mosquitoes.