| Popis: |
As one kind of cost-effective, efficient and environment-friendly materials for direct control of mosquitoes, botanicals have been widely concerned. The present study has evaluated the synergistic effect of different blends of seed methanolic extract of Cuscuta chinensis ( C. chinensis ) with its assumed synergist Asparagus setaceus ( A. setaceus ) against larval instars of Culex quinquefasciatus ( Cx. quinquefasciatus ). Different larval instars were exposed to 100 ppm to 300 ppm concentrations separately and in blends at different ratios of prepared extracts of tested plants as per WHO protocol. Major seed secondary metabolites of interest were analysed. This study recorded the highest mortality at 300 ppm for both the plants against all instars in 72 h. In combinatorial bioassay, A. setaceus and C. chinensis at the ratio of 1:2 was more effective as a larvicide and it encountered (98.68±0.00)%, (97.32±0.33)%, (85.32±0.33)% and (94.68±0.33)% death of 1 st , 2 nd , 3 rd and 4 th instars larvae at 300 ppm concentration respectively after 72 h of exposure. In addition, the SF (Synergistic Factor) and CTC (Co-toxicity Coefficient) values indicated synergism. These results have suggested that the botanical blend of tested plants possesses a suitable property which may be exploited as a source of the larvicidal product to replace harmful chemical pesticides. |
