Toxicity and biochemical efficacy of six essential oils against Tribolium confusum (du val) (Coleoptera: Tenebrionidae)

Abstract

Six essential oils extracted from  garlic  (Allium sativum), mint (Mentha piperitaa), basil (Ocimum basilicum), thyme  (Thymus vulgaris ) , sesame (Sesamum Indicume) and chamomile (Chamaemelum nobile) were tested for both  repellency and toxicity  against the  confused  flour  beetle,  Tribolium confusum adults and  last larval instar. Two kinds of repellency bioassays were performed by using filter paper tests and treated kernels.  The toxicological bioassay was performed by topical application. The results showed that the tested oils were highly repellent to the adult insect compared to the larvae. By contrast, the toxicological bioassay showed that larvae were more susceptible to tested essential oils than the adults.  Effects of essential oils on five detoxification enzymes were also investigated. A reduction in total activities of the major detoxification enzymes in treated larvae was also observed.