Potential Insecticidal Activity of some Medicinal Plants Essential Oils against Red Flour Beetle ,Tribolium castaneum (Herbst) (Coleoptera:Tenebrionidae).

Abstract

Tribolium castaneum is a major pest of wheat grain flour. Studies were carried out to investigate the insecticidal activity of essential oils (EOs) extracted from locally grown seven medicinal plant such as ginger (Zingiber officinale), garlic (Allium sativum), thyme (Thymus vulgaris), clove (Syzygium aromaticum), dill (Anethum graveolens), eucalyptus (Eucalyptus globulus) , and lemon (Citrus limon) against Tribolium castaneum. In addition, Gene expression analysis for three insecticide resistance genes (Cytochrome P450 similar gene, CYP4Q4 and CYP4Q7) that mediated the detoxification mechanism, The EOs showed effective mortality of adult and larval stages of tested insect at concentration levels (6.25, 12.5 and 25) and exposure periods under laboratory conditions as compared with untreated experiments. Overall results, among essential oils A. graveolens and S. aromaticum showed highest mortality rate, followed with T. vulgaris and A. sativum while the minimum mortality rate was in E .globules against T. castaneum adult and larval stage, highest LC 50 values was recorded in Anethum graveolens (LC 50 at 1.5 hrs),it is note worthy that larvae more sensitive to EOs than adult in addition, Eos showed maximum expression level in T. castaneum larval stage was in Cytochrome P450 similar gene 3.38 Fold changes in mRNA, followed with CYP4Q4 and CYP4Q7 were 2.21 fold and 1.41 fold respectively as compared with reference gene (house keeping gene, β-Actin). Hence, these EOs of investigated plants may be recommended as botanical insecticide to control of stored grain insect, T. castaneum.