Use of Castor and Garlic Oils to Control the Red Flour Beetle, Tribolium castanium

This study investigated the repellency effect and killing efficiency of castor and garlic oils to control adults and larvae of the red flour beetle, Tribolium castanium. The results obtained showed a significant repellency effect of plant oils on the insect adults with a higher repelling effect of garlic oil, which reached 100%, 20 minutes after treatment with 30% concentration, as compared to 100% for castor oil, 30 minutes after treatment at the same concentration. The results obtained also indicated the superiority of garlic oil’s effect on larval mortality (first, second, and last instars), which reached 86.6, 90.0 and 73.3%, 5 days after treatment with 30% concentration, for the different larval stages, respectively. Furthermore, the highest mortality rate of insect adults (76.7%) was also reached when garlic oil was used at a concentration of 30%, 5 days after treatment, followed by castor oil (66.7%) at the same concentration and period after treatment. Keywords: Red flour beetle, T. castaneum, stored grains, plant oils.