Effectiveness of medicinal plant powders on Sitophilus granarius and Tribolium confusum

Medicinal plant powders have traditionally been used as grain protectants against stored-product insect pests. In this study, insecticidal activities of Carum copticum L. and Cuminum cyminum L. powders were assessed on adults of Sitophilus granarius L. and Tribolium confusum Jacquelin du Val. Experiments were carried out on wheat at 27 ± 1 ?C and 55 ± 5% r. h. The mortality increased with increasing concentration level and time exposed to each concentration. For S. granarius, 7 days and in case of T. confusum 14 days exposure time was sufficient to obtain considerable mortality. For example, 3500 mg/kg of C. copticum 7 days after treatment caused 80% mortality in S. granarius; while for T. confusum 29% mortality was achieved and increased to 100% after 14 days. Therefore, it can be concluded that adults of S. granarius were more susceptible than T. confusum to plant powders. Also, according to the findings, C. cyminum powder had more insecticidal efficacy than C. copticum on both insect species. For S. granarius, 950 and 2700 mg/kg powders of C. cyminum and C. copticum was enough to cause ca. 50% mortality after 5 days, respectively. In the case of T. confusum, 3200 and 4400 mg/kg of the plant powders caused the same mortality after 7 days. Findings of the present study show that the plant powders could be applied for grain protection in small-scale storage facilities.