Chemical Composition and Insecticidal Activity of Essential Oils from Cinnamomum austroyunnanense H. W. Li against...

Cinnamomum austroyunnanense is a traditional Chinese medicinal plant that is thought to be developed as a biological insecticide. Essential oils (EOs) of C. austroyunnanense fresh leaves over different extraction periods (0-90, 90-180, 180-315, 315-540 minutes) were investigated for their chemical composition and insecticidal activities. The chemical components of EOs were analyzed by GC-MS. Methyl eugenol was the primary component in all EOs (68.06 %, 90.91 %, 75.73 %, 40.62 %). The target insects were Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. The results showed that the EOs had significant fumigation effects on L. bostrychophila, but poor fumigation effects on T. castaneum and L. serricorne. All four EOs exhibited contact toxicity against L. serricorne and L. bostrychophila, but only the first and second time period oils showed contact toxicity against T. castaneum with LD₅₀ values were 25.87 µg/adult and 40.00 µg/adult, respectively. The EOs also demonstrated repellent activity against three insects. EO's repellent effects were comparable to N,N-diethyl-3-methylbenzamide (DEET) at the highest concentrations. As the concentration decreased, the repellent effect gradually turned into an attractant effect. This research confirmed that C. austroyunnanense EOs possessed insecticidal potential and offered scientific guidance for its efficient extraction, demonstrating its promise as a novel eco-friendly insecticide.