Repellent and Toxicant Effects of Eight Essential Oils against the Red Flour Beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae)

Abstract

This study was conducted to compare the repellent effect and contact toxicity of eight essential oils (EOs), including <i>Syzygium aromaticum</i>, <i>Allium sativum, Eucalyptus camaldulensis</i>, <i>Lavandula officinalis</i>, <i>Simmondsia chinensis</i>, <i>Matricaria chamomilla</i>, <i>Citrus limon</i>, and <i>Prunus dulcis</i>, against adults of <i>Tribolium castaneum</i> Herbst. Four concentrations (1, 5, 10, and 15% in acetone solvent) of each EO were tested. The 5, 10, and 15% concentrations of <i>S. aromaticum</i> EO had a high repellency effect against <i>T. castaneum</i> compared with <i>A. sativum</i>, <i>E. camaldulensis</i>, <i>L. officinalis</i>, <i>S. chinensis</i>, <i>M. chamomilla</i>, <i>C. limon</i>, and <i>P. dulcis</i> after 30 min of exposure. The repellency test of the <i>S. aromaticum</i>, <i>E. camaldulensis</i>, <i>L. officinalis</i>, <i>M. chamomilla</i>, <i>C. limon</i>, and <i>P. dulcis</i> EOs on <i>T. castaneum</i> has shown that the mortality percentages enhanced with the increase in the EOs concentration and also with the exposure time. The 15% concentration of <i>P. dulcis</i> and <i>M. chamomilla</i> EOs have a significant impact on the mortality rate of <i>T. castaneum</i> compared with <i>S. aromaticum</i>, <i>A. sativum, E. camaldulensis</i>, <i>L. officinalis</i>, and <i>S. chinensis</i> after the 24 h of contact test. Moreover, the 15% concentration of the <i>C. limon</i> EO caused a greater mortality percentage compared with <i>S. aromaticum</i>, <i>A. sativum, E. camaldulensis</i>, and <i>L. officinalis</i>. It could be concluded that using the <i>S. aromaticum</i> EO as a repellent oil and using <i>P. dulcis, M. chamomilla</i>, and <i>C. limon</i> for contact toxicity to treat the flour infested by <i>T. castaneum</i> can play an important role in protecting stored grains and their products.