| Oxalie acid (OA) is an important pathogenic factor in the pathogenicity process of Sclerotinia. Choosing the bacteria that can degrade OA is the target of this thesis. The screen may be divided into three steps: First, adjustment of pH values. We use medium containing 0. 3%?. 5% OA to culture the selected bacteria and choose those that can heighten the number of pH. Second, Test of HPLC .The peak value is lined with the content of OA, We may compare the change of peak value to determine whether the oxalic acid is degraded. Last, Experiment of rice?s emerging. When added with 2000ppm OA, the emergency of the rice can be inhibited. The less of the OA is the less of the inhibition. 3æ¢eaves棗old of rape (Brassica napus) being acted with U? 1 ~ SOOppm OK. l000ppm OK. 2000ppm OK~ the mixture of U梚 and 2000ppm OA ~, their PAL~ P0 and PPO activities changed differently during 60 hrs. In 12 hrs, the activities of PAL may be increased 39%, compared with the check. But the l000ppm and 2000ppm OA inhibit the activities of PAL. In 24 hrs 3 kinds of enzymatic activity of nape may induce the improvement of P0 and the numbers are l0%~ 20%~. 30% respectively, but they drop greatly with the time going on. Three concentrations of OA may drop the activities of PPO in l2hrs. Compared with the check, the rates of reduction are 36%~ 52%~. 64% 3 respectively . With the action of the mixture of U梚 and 2000ppm OA, three enzymatic activities improved, compared with the 2000ppm OA. On the basis of the prior research, we study the effect of U梚 on leaves of nape and in the field. In the room, the leaves handled with Lb-i, compared with the check, the incidence of the disease dropped 47% and the area of the disease dropped 56%. The field experiments were carried on in Xuyu and Nantong. In Xuyu, the pathogenic strain and control effect dropped 57%~. 61%. In Nantong, they were 32%~ 68%. U梚 was identified as Arthrobacter sp according to Bergy?s manuaiof systematic bacteriology.
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