Efficacy of Cupressus sempervirens essential oils against Trogoderma granarium everts (Coleoptera: Dermestidae)

The seeds and leaves of Cupressus sempervirens essential oils were evaluated against the khapra beetle, Trogoderma granarium at different concentrations. Mortality, repellence activity, adult emergence rate, larvae chemical profile (protein contents and energy reserves), seed germination effect, and grain damage were assessed. The results of phytochemical screening of C. sempervirens leaf and seed demonstrated the presence of saponins, flavonoids, leucoanthocyanins, catechetical tannins, and gallic tannins. We identified eighty-two (82) compounds for leaves and seventy-four (74) for seeds by GC/MS. The major compounds for leaf and seed EOs were α-pinene (33.65% and 26.53%), δ-3-Carene (14.78% and 19.48%) and terpinolene (4.25% and 4.13%), respectively. C. sempervirens exhibited fumigant toxicity and repellent activity as a function the concentrations. C. sempervirens leaves was most potent both in adult emergence (66.94%) and germination rate (99%) compared to seeds oil. Furthermore, the seed and leaf oils significantly reduced seed damage. Finally, the treatments induced an alteration of the biochemical profile via a decrease in energy reserves and protein content. The data obtained suggest that the toxicity of EO by fumigation could be explained by an alteration of insect metabolism via food uptake and digestion.