| Popis: |
In preparation for designing a strategy of integrated management associated with post-harvest products in Senegal, the bioactivity of crude and extracts of Calotropis procera Ait. on the survival of eggs and adults Caryedon serratus (Ol.) pest of groundnut, Arachis hypogaea L., was studied under controlled conditions. The crude extracts (ether and methanol) and fractions of extract (hexane, ethyl acetate and methanol) were applied through contact with C. serratus at different concentrations C1 (0.1 g of dry residue / ml of solvent dilution), C2 (0.01 g/ml) and C 3 (0.001 g/ml). The action of each biocid extract of C. procera on the survival of treated is dependent on the concentration and varies with the polarity of the extract. All concentrations induce high mortality of C. serratus eggs and adults regardless of the sample in use. The most important (86.14 ± 4.21%) adulticidal action was noted in 10 days of treatment with the methanol fraction. The adulticidal effect of crude methanol extract on C. serratus was in the range of 74.10 ± 2.82%. The biological activity of extracts of C. procera on the insect is also expressed by an imbalance of sex-ratio in favor of males, an extension or a reduction in the duration of the phases of development, reduced fecundity and fertility limited. The fecundity averages, less important, were obtained with the hexane fraction (44.83 ± 3.01 eggs) and high concentrations of ethyl acetate fraction (35 ± 0.71 eggs) or a respective rate of reduction of spawning 52.93% and 63.25% compared to the control. After characterization of reactions, it is clear from this study that the bioactivity of extracts of C. procera is likely related to suspected active compounds (alkaloids, flavonoids, tannins, anthracene derivatives, saponins, sterols and terpenes) as revealed from staining or precipitation using specific reagents. |
