Chemical Constituents and Insecticidal Activities of the Essential Oil ofCinnamomum camphoraLeaves againstLasioderma serricorne
During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oil ofCinnamomum camphoraleaves was found to possess strong fumigant and contact toxicity againstLasioderma serricorneadults with LC50/LD50values of 2.5 mg/L air and 21.25 μg/adult, respectively. The essential oil obtained by hydrodistillation was investigated by GC and GC-MS. The main components of the essential oil were identified to beD-camphor (40.54%), linalool (22.92%), cineole (11.26%), and 3,7,11-trimethyl-3-hydroxy-6,10-dodecadien-1-yl acetate (4.50%). Bioactivity-directed chromatographic separation on repeated silica gel columns led to the isolation ofD-camphor and linalool.D-camphor and linalool showed strong fumigant toxicity (LC50= 2.36 and 18.04 mg/L air, resp.) and contact toxicity (LD50= 13.44 and 12.74 μg/adult, resp.) againstL. serricorne. The results indicate that the essential oil ofC. camphoraand its active compounds had the potential to be developed as natural fumigants and insecticides for control ofL. serricorne.