For clubroot, use 75% chlorothalonil 800 times solution and 10% cyanofenazole 1500 times solution for seedbed disinfection; before transplanting, use 50% fluazinam for soil treatment; before sowing, use 75% chlorothalonil and 1500 times solution 70% thiophanate methyl and 2% of the dry seed amount are used for seed dressing; in the field period, 10% cyanofenazole 1500 times solution, 75% chlorothalonil 600 times solution, 70% thiophanate methyl 600 times solution and other chemicals are used for root irrigation. Generally, it is administered once every 7-10 days and 3-4 times per day.