According to the characteristics of clubroot occurrence in broccoli，this paper studied the control
effect of 50% fluazinam suspension（SC）on clubroot and safety for plant growth in seedling and adult-plant stages
by 2 different applying methods：one was homogeneously stirred seedling substrate while sowing，the other was
root-irrigation at different dates after transplanting in field．The results showed that the growth of seedling was
inhibited severely by 3 concentrations of 50% fluazinam SC．Compared with the control group，the plant height
became shorter，and first true leaf became smaller．The higher the concentration was，the more obvious the
inhibition was．So fluazinam was not suitable to be used in the seedling stage．Meanwhile，the rate of emergence
was not significantly affected．The control effect was variant，as applying 50% fluazinam SC irrigating root after transplanting in field at different dates．The relative control effect of treatment with root-irrigation at 3 days and
30 days after transplanting was extremely the best，reaching 92.21%，which was extremely significantly superior
to the other treatments．The second way was conducting root- irrigation at 3 days after transplanting．The relative
control effect was 74.03%，which was extremely significantly better than that after disease onset．The control
effect of the treatment of 2 times was obviously better than that of the treatment of 1 time．Meanwhile，the control
effect of treatment before symptom appeared was better than that of the treatment afterwards．