Insecticidal Activities and Chemical Composition of the Essential Oils of Ajania nitida and Ajania nematoloba from China.

Abstract

In this work, we investigated insecticidal and repellent activities of the essential oils extracted from Ajania nitida and Ajania nematoloba against Tribolium castaneum and Lasioderma serricorne adults. The components of essential oils were analyzed by GC-MS. The main components of A. nitida oil were camphor (20.76%), thujone (18.64%), eucalyptol (13.42%), borneol (8.32%) and those of A. nematoloba oil were β-pinene (34.72%), eucalyptol (24.97%) and verbenol (20.39%). The results showed that the two essential oils possessed insecticidal and repellent activities against two species of insects. A. nitida oil possessed contact and fumigant toxicity against T. castaneum (LD50 = 30.10 µg/adult and LC50 = 21.07 mg/L air) and L.serricorne (LD50 = 17.51 µg/adult and LC50 = 11.23 mg/L air). A.nematoloba oil showed contact and fumigant toxicity against T. castaneum (LD50 = 102.29µg/adult and LC50 = 69.45 mg/L air) and contact toxicity against L.serricorne (LD50 = 53.43 µg/adult), but no obvious fumigant effect was observed against L.serricorne. Both of essential oils possessed strong repellent activity against T. castaneum and certain repellent activity against L.serricorne. Especially, A. nematoloba oil showed the same level percentage repellency as DEET(the positve control) against T. castaneum. The results indicated that the essential oils of A. nitida and A. nematoloba had the potential to be developed as natural insecticides and repellents for the control of T. castaneum and L.serricorne.