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 activity of Carum copticum L. and Cuminum cyminum L. powders was assessed on adults of Sitophilus granarius L. and Tribolium confusum Jacquelin du Val. Experiments were carried out on wheat at 27 ± 1 ºCand 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 is sufficient to obtain considerable mortality. For example, 3500 mg/kg of C. copticum 7 days after treatment caused 80% on S. granarius; while for T. confusum 29% mortality was achieved and exceeded 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 has more insecticidal efficacy than C. copticum on both insects’ species. For S. granarius, 950 and 2700 mg/kg powders of C. copticum and C. cyminum was enough to cause ca. 50% mortality after 5 days, respectively. In case for T. confusum, 3200 and 4400 mg/kg of the plant powders caused same mortality after 7 days. Findings of the present study shows that the plant powders could be applied in grain protection of small-scale storage facilities.