Powders and extracts of Syzygium aromaticum and Anacardium occidentale as entomocides against the infestation of Sitophilus oryzae (L.) [Coleoptera: Curculionidae] on stored Sorghum grains

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\ub12 \ubaC and 75\ub15% 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.Sitophilus oryzae est une peste majeure des grains de sorgho (Sorghum bicor L.) en stockage au Nigeria. Ainsi une \ue9tude a \ue9t\ue9 r\ue9alis\ue9e pour \ue9valuer les effets entomocides de Syzygium aromaticum et Anacardium occidentale \ue0 une temperature ambiante de 28\ub12 \ubaC et une humidit\ue9 relative de 75\ub15%. Les poudres \ue9taient appliqu\ue9es aux taux de 0,5\ua0; 1\ua0; 1,5\ua0; 2,0 et 2,5 g par 20 g de sorgho grains, tandis que les essences \ue9taient appliqu\ue9s aux taux de 1, 2, 3 et 4% par 20 g de sorgho grains. Aussi bien la poudre que les essences de S. aromaticum et A. occidentale pr\ue9sentent des effets insecticides sur S. oryzae. Cependant, la poudre de S. aromaticum \ue9tait plus efficace que celle de A. occidentale; car celle-ci assure une mortalit\ue9 totale (100%) des charan\ue7ons du riz pour toutes les concentrations test\ue9es et ceci en 96 heures d\u2019application. Les essences \ue9taient plus efficaces que la poudre sur les adultes du charan\ue7on du riz. De m\ueame, les essences de S. aromaticum sont plus efficaces que celles de A. occidentale. Toutes les deux essences emp\ueachent l\u2019\ue9mergence des adultes et la perte pond\ue9rale des grains de sorgho pour toutes les concentrations appliqu\ue9es. La seule exception \ue9tait les essences de A. occidentale qui ont permis une \ue9mergence d\u2019adultes de 1.2% et une perte pond\ue9rale en grains de sorgho de 0.89%