Caryophyllene oxide from bioassay-guided fractionation of Toona sinensis essential oil shows insecticidal activity against poultry red mite (Dermanyssus gallinae)

The widespread distribution and ecumenical abundance of the poultry red mite, Dermanyssus gallinae (De Geer), in chicken houses, has been bringing about one intractable challenge for the egg-laying hens. However, because of the appearance of drug resistance and the animal safety legislation, the search for some effective insecticidal agents is necessary. In the present investigation, the essential oil extracted from the tender shoots and young leaflets of Toona sinensis (Chinese toon, TSEO) were demonstrated to be not only display significant antioxidant effect, but also revealed prominent insecticidal activity against the poultry red mite. Briefly, in contact toxicity bioassay, the LC₅₀ value was 7.3 μg/mL. In fumigant toxicity bioassay, the highest mortality in the closed container method, and the mortality was 72.5 %. In repellent activity bioassay and residual toxicity bioassay, when TSEO was administrated at the concentration of 20.0 μg/cm³, 89.2 % of mites were repelled for up to six days. Moreover, caryophyllene oxide, was considered to be the compound in TSEO that displayed insecticidal effect against the mites. Therefore, together with the essential oil TESO, caryophyllene oxide can be developed and employed as potential insecticidal agents against the mites in future.