Research Article
Hosny AH, Hasan NE, Zayed G
Abstract
The rice weevil Sitophilus oryzae is one of the most important pests of stored products which attacks grains causing weight loss and reduced nutrition values. Laboratory experiments were conducted to evaluate the insecticidal activity, as well as the repellent effect of marjoram Origanum majorana, oil and powder, against adults of S. oryzae compared to malathion insecticide. The chemical composition of marjoram oil was identified by GC-MS analysis. The results indicated that fumigant toxicity of marjoram oil was the most effective against adults of S. oryzae. Based on the contact toxicity 7days post-treatment at the highest concentration marjoram oil with LC50 values of 0.533, the mortality was achieved 90.0% and reduction in adult F1 progeny reaching maximums of 81.2%. Also, the mortality in fumigant toxicity of marjoram oil was achieved 88.3% and reduction in adult F1 progeny reaching 86.9%. In addition, all treatments decreased the wheat grain weight loss with increasing the concentration compared to control. The repellent effect of marjoram oil was more effective than its powder especially at the highest concentrations. With regard to the results of the current study it could be suggested that marjoram oil and powder may have potential to be used as an alternative to insecticides in an integrated pest management program for protection stored grains