Antioviposition and Reduction of Callosobruchus chinensis Pic. 1902 (Coleoptera: Bruchidae) Emergence on Phaseolus vulgaris by Dioscorea sansibarensis Powder and Its Chemical Composition

Abstract

Callosobruchus chinensis causes damage to the Phaseolus vulgaris seeds. Traditionally, Dioscorea sansibarensis serves as a medicinal plant. Naturally, D. sansibarensis has toxins that protect against herbivores and the surrounding invasive plants in its natural habitat. Phytochemical analysis by thin-layer chromatography (TLC) and laboratory experiments was carried out to determine the activity of D. sansibarensis leaves, bulbils, and yams powders on antioviposition and inhibition of the F₁ emergence of C. chinensis. Bioassay data were subjected to nonparametric (Kolmogorov–Smirnov) statistical analysis and a generalized linear model at . Statistically, the powders had an antioviposition activity of 34.3% (R² = 0.343). A recommendable activity on antioviposition was displayed by the yams powder; treatment by 0.8 g of yams powder had a Wald Chi-Square value of 1.291, . Inhibition of F₁ emergence was significantly attained by the yams powder; the treatment by 0.6 g of yams powder had a Wald Chi-Square value of 7.72, . Statistically, the bulbils powder displayed low antioviposition and inhibition of F₁ emergence. Observations on the TLC exposed compounds with similar Rf values; saponin with an Rf value of 0.72 was portrayed in the leaves, bulbils, and yams. A terpenoid and a flavonoid with Rf values of 0.37 and 0.71, respectively, were observed...