Repellent Constituents of essential oil from Citrus wilsonii stem barks against Tribolium castaneum.

The essential oil obtained from Citrus wilsonii Tanaka stem barks with hydrodistillation was investigated by GC-FID and GC-MS. The main components of the essential oil were identified to be nerol acetate (44.5%), nerol (13.6%), citronellyl propionate (13.5%) and α-terpineol (3.6%). Among them, the four active constituents, predicted with a bioactivity-test, were isolated and identified as nerolacetate, nerol, citronellyl propionate and α-terpineol. It was found that the essential oil of C. wilsonii stem barks possessed strong repellency (86% and 92%, respectively, at 78.6 nL/cm2, after 2 and 4 h treatment) against Tribolium castaneum adults. Repellency of the four active compounds was also determined. Nerolacetate, nerol, citronellyl propionate and α-terpineol were strongly repellent (100%, 100%, 90% and 96%, respectively, at 15.7 nL/cm2, after 2h treatment) against T. castaneum. Nerol exhibited the same level of repellency as the positive control, DEET. The results indicate that the essential oil of C. wilsonii stem barks and its active compounds have the potential to be developed as natural repellents for control of T. castaneum.