The direct and subsequent effects of saponins obtained from aboveground parts of alfalfa (Medicago sativa L.) on development and fertility of grain weevil (Sitophilus granarius L.) were investigated. The results have revealed that life cycle of grain weevil prolongs along with an increase in saponin concentration, whereas duration of the offspring generation emergency decreases. Also, a significant reduction in grain weevil fertility was observed. Strong subsequent effect of saponins on the offspring generation bred on untreated wheat was recorded. Prolongation of the life cycle and duration of the offspring generation emergency of grain weevil was noted in comparison with the results from tests of the direct effect. Moreover, the fertility index of the offspring generation was lower.

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