Antifeedant properties of extracts derived from different parts of some medicinal plants against the granary weevil, Sitophilus granarius Linnaeus, and 1758 (Coleoptera: Curculionidae)

Abstract

The different solvent extracts (viz. Chloroform, Hexane and Methanol) obtained from leaves and flowers of Common Dandelion, Taraxacum officinale and St. John’s Wort, Hypericum perforatum were researched for antifeedant activity against the wheat weevil, Sitophilus granarius. All the six different extracts showed antifeedant activity at four different concentrations. The methanol extracts of leaves of Taraxacum officinale and Hypericum perforatum exhibited significant activity at 4% concentration. The numbers of seed holes produced were only 16.67 and 21.00 respectively, which are significantly less than the number of seed holes produced in control group, 102.00 and 97.33 respectively. The treatment with methanol extracts of flowers of both the plants significantly reduced the number of feeding holes to 18.00 and 22.67 respectively in comparison to the control group values of 100.00 and 99.00. All the efficiencies are dose dependent. The mean results with SEM (mean ± SE) were statistically significant at 1% level (p<0.01) for three treatments.