Nematicidal Activity of Essential Oil from Four Species of Cupressaceae against Bursaphelenchus xylophilus

Essential oils were extracted by steam distillation from four species of Cupressaceae, namely Chamaecyparis obtuse, Ch. pisifera ‘Plumoso’, Ch. pisifera, Ch. obtusa var. formosana for experiment of their nematicidal activity by immersion method against Bursaphelenchus xylophilu. B. xylophilus was treated with different concentrations of essential oils for 24 h, 48 h and 72 h. The results showed the inhibitory effect of essential oils from four species of Cupressaceae on B. xylophilus had positive relation with duration and concentration. The median lethal concentration (LC50) of four essential oils from Ch. obtuse, Ch. pisifera ‘Plumoso’, Ch. pisifera, Ch. obtusa var. formosana 72 h later was 2.84 mg/mL, 2.77 mg/mL, 2.37 mg/mL and 1.76 mg/mL respectively. The essential oil from Ch. obtusa var. formosana had the best effect.