POWDERS AND EXTRACTS OF Syzygium aromaticum AND Anacardium occidentale AS ENTOMOCIDES AGAINST THE INFESTATION OF Sitophilus oryzae (L.) [Coleoptera: Curculionidae] ON STORED SORGHUM GRAINS

摘要

Sitophilus oryzae is a major pest of sorghum (Sorghum bicor L.) grains in storage in Nigeria. Thus a study was conducted to evaluate the entomocidal bustle of Syzygium aromaticum and Anacardium occidentale at ambient temperature of 28±2 °C and 75±5% relative humidity. The powders were applied at rates of 0.5, 1.0, 1.5, 2.0 and 2.5 g per 20 g of sorghum grains, while oils were applied at rates 1,2,3 and 4% per 20 g of sorghum grains. Both the powders and oils of S. aromaticum and A. occidentale showed insecticidal effects on survival of the S. oryzae. However, the powder from S. aromaticum was more effective than that of A. occidentale; as it achieved 100% weevil mortality at all the tested concentrations within 96 hours of application. The oils caused more mortality on adult S. oryzae than their powder counterparts. Similarly, the oils of S. aromaticum are more effective than those of A. occidentale. Both the oils prevented adult emergence of the weevil and weight loss of the sorghum grains at all concentrations. The only exception was the oil of A. occidentale which recorded 1.2 and 0.89% adult emergence and seed weight loss, respectively.