Toxicity of plant extracts and powders on mobile stages of the hairy grain beetle Trogoderma granarium (Everts) (Coleoptera: Dermestidae)

An experiment was conducted on Trogoderma granarium larvae using extracts of L. nobilis and L. officinalis plants and the effect of both at concentrations of 3, 6, 9 and 12 g/100 ml,, and at exposure periods of 1, 3, 6, 9 and 12 days, respectively., the research aimed to determine optimal insecticidal doses and compare extracts and powders of two substances for optimal effects and timing. The results showed that the extract of L. officinalis plant was better than the extract of L. nobilis, as the mortality rates reached 76.66 and 63.33 mortality rates, with mortality rates reaching 100%. The results of using powders of the leaves of L. nobilis and L. officinalis on the insect larvae showed results of 39.99 and 53.33%, respectively, during the exposure period of 60 days at a concentration of 12%. As for its effect on the percentage of mortality in adult insects, it was at higher rates during the exposure period of 12 days and the concentration of 12% grams/100 Trogoderma granarium ml, with mortality rates reaching 30.0% and 39.99%, respectively. When studying the effect of plant extracts and powders at a concentration of 12% g/100 ml and 12 g/kg for each of the two plants, respectively, L. nobilis and L. officinalis, the statistical differences were significant for the effect of all treatments compared to the control treatment in the number of eggs laid by one female, hatching rates, duration of the larval stage, and the sex ratio of emerging females, as it was positively affected, reducing the damage of the insect compared to the control treatment, and the sex ratio of emerging females reached 33.0, 41.33, 26.99, and 33.66%, respectively, compared to 48.33% in the control treatment.