In this study, botanicals extracted from two the species of family Scrophulariaceae, Verbascum cheiranthifolium Boiss and Verbascum speciosum Schard, were examined for their effect on mortality and progeny production against adults of Sitophilus oryzae (L.). The plant extracts were applied at five dose rates, which 0.25, 0.5, 1.0, 2.0 and 3% (w/v). Adults of S. oryzae was exposed to the treated wheat at 25 degrees C and 65% RH and mortality was assessed after 24 h, 48 h, 7 day, 14 day and 21 day of exposure. Then all adults were removed and the treated substrate remained at the same conditions for an additional 45 day after this interval, the commodity was checked for progeny production. In use two extracts the mortality of adults increased with the increase of dose and exposure interval so that; mortality was 100% after 21 days of exposure at the highest dose rate. Results indicated that applied of V. cheiranthifolium extract was more effective than V. speciosum against adult insects. Interestingly, in two cases complete suppression (100% reduction) of the progeny production (F1) was observed in the treated wheat than in control even in the lowest dose rate. Therefore, our results indicate that these medicinal plants can be used for protection of stored grain from infestations of stored-product insect pests.

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Tissues of higher plants contain novel natural substances that can be used to develop environmental safe methods for insect control. In this study, ethanol extract from flowers of Verbascum cheiranthifolium Boiss. (Scrophulariaceae) was examined for their effect on mortality and progeny production against adults of Rhyzopertha dominica (F.) on two commodities, wheat and barley. The botanical extract was applied at five dose rates, which 0.25, 0.5, 1.0, 2.0 and 3% (w/v). Adults of R. dominica were exposed to the treated wheat and peeled barley at 25 degrees C and 65% RH and mortality was assessed after 24 h, 48 h, 7 day, 14 day and 21 day of exposure. Then all adults were removed and the treated substrate remained at the same conditions for an additional 45 day after this interval, the commodities were checked for progeny production. In two commodities mortality increased with the increase of dose and exposure interval. Results indicated that on wheat, mortality was 100% after 14 days of exposure at the highest dose rate. Whereas, in the same conditions mortality of adults on barley was 63%. Thus plant extract was more effective against adults of R. dominica on wheat than application of barley. Interestingly in two diets, complete suppression (100%) of the progeny production was observed in the treated wheat and barley than in control even in the lowest dose rate.