Study On Essential Oils Of Several Woody Plants Against Plant Pathogens

Plant essential oils ,which had many merits ,were seen to exert great application potentiality in plants protection as one kind of the very important derivatives. The research is to find out some substance from woody plant essential oils against plant pathogens for the development of botanical pesticides. In this paper,essential oils of 7 plants were extracted with vapor-distillation. Based on this,the best inhibitory efficiency oil was screened through testing 9 kinds of phytopathogenic fungi by using mycelial growth rate method and determined for further antifungal activity In vitro and in vivo.Meanwhile, nematicidal activity were investigated for 7 kinds of plants essential oils against Bursaphelenchus xylophilus in vitro.The resulsts were as follows:1.7 kinds of plants had different oil yields. Cinnamomum camphora had the highest oil yields(15.0 uL. g-1)than the others(2.9-5.0 uL. g-1).The yields of the 7 plants were ranked as follows:C.camphora>Magnolia cylindrical>M. grandiflora >Torreya grandis>Pinus elliottii>P. massoniana >P.thunbergii.2. The essential oil of M. cylindrical had the strongest antifungal efficacy on the most of tested fungi under the concentration of 500 uL . L -1. Inhibition rates of seven fungi were above 50%;Valsa mali and Fusarium graminerum were more sensitive to the oil ,with the inhibition rates of 95.23% and 93.83% respectively.3. The essential oil of M. cylindrical had strong toxicity agaist the mycelial growth and spores germination of fungi. EC50 values to 6 sentive fungi were ranged from 147.94-223.73 uL . L -1,the minimum and maximum were recorded in V.mali and Sclerotinia sclerotiorum. EC50 values to Botrytis cinerea and Pyricularia oryzae were 506.07 uL . L -1 and 599.93 uL . L -1.4. The essential oil of M. cylindrical had good inhibitory efficiency against B. cinerea on tomato and cucumber leaf in vivo, but had differenc in these two samples. The results showed that its therapy efficacy against B.cinerea on these two differen samples were better than its protective efficacy.And at the concentration of 1000 uL . L -1,the therapy efficacy were 55.21% and 33.85%, the protective efficacy were 41.32% and 22.37%,respectively. But, the result in vivo showed that the oil had no significance efficacy against the Penicillium italicum on oranges.5. The essential oil from M. cylindrical and T. grandis also had good nematicidal activity against B. xylophilus,LC50 values were 947.10 uL . L -1 and 960.47 uL . L -1 respectively.The study indicated that the essential oil from M. cylindrical had highly antifungal efficacy and good nematicidal activity against B. xylophilus, were needed for further study.