Studies On The Inhibition Effects Of Gross Extracts Of Dioscorea Zingiberensis Wright CH.on Main Crop Fungus And Bacteria

Huajiang, also named Dioscorea zingiberensis Wright C.H. Its stem underearth can be used as food, and as Chinese medicine too. The sapogenin extracted from its stem is not only an important material to compose cortisone and the other hormonal medicines but also has somewhat inhibition effect on fungus.The roots and leaves of Dioscoreaceal zingiberensis C.H.Wright were researched in this paper, which were comminuted after airing and drying in 50-60℃ ,then the plant materials were extracted with methanol, acetone, ethanol and their mixture as solvents by cold dipping.Fungus selected in experiment mainly were Rhizoctonia solani Kuhn., Fusarium oxysporum schlechendahl f.sp.niveum., Fusarium graminearum Schwabe.; Bacteria selected were Xanthomonas campestris pv. Orvzae (Ishiyama) Dye., Erwinia caratovora (Jones) Hou pv. caratovora Dye. The mycelial growth rate measurement and the bacteria liquid culture method were used.The restraint experiments show that gross extracts have deferent controlling effects on fungus and bacteria. In the culture dish experiments on fungus, the inhibition rates(24h) of root gross extracts(0.01g/ml) on Rhizoctonia solani Kuhn. and Fusarium oxysporum schlechendahl f.sp.niveum. are 100% , 23.35% respectively, the inhibition rate(48h) on Rhizoctonia solani Kuhn., Fusarium oxysporum schlechendahl f.sp.niveum. and Fusarium graminearum Schwabe. are 78. 64%, 13. 64% , 38. 89%. In the culture dish experiments on bacteria, the inhibition rates(24h)of gross extracts(4%) on Xanthomonas campestris pv. Orvzae (Ishiyama) Dye. and Erwinia caratovora (Jones) Hou pv. caratovora Dye. are 51.67% and 61.24%. The liquid culture experiments also show that inhibition rates(24h) of gross extracts(5%) on Xanthomonas campestris pv. Orvzae (Ishiyama) Dye and Erwinia caratovora (Jones) Hou pv. caratovora Dye are 68.29% and 64.31%. The experiments of gross extracts plus fungicide certificates that they can produce synergy effect. The best economic ratio of extract plus fungicide on Rhizoctonia solani Kuhn. is finally determined as l:18ppm.