B. oleracea occurs mostly in high-temperature, high-humidity areas and seasons, and it can be affected during the seedling and adult plants, and it often causes death. Symptoms can be onset at both seedling stage and adult stage. At the seedling stage, light brown lesions, round or oval, were produced on the cotyledons, true leaves, and young stems. Small black spots were scattered on the seedlings for the conidia; the lesions on the young stems were slightly sunken. Severe disease seedlings soon died. In the adult leaf stage, the lesions are the same as in the seedling stage, and purple-black streaks appear on the lateral roots of the primary root, causing the roots to decay, or to collapse from the diseased stems. Prevention of disease-free seed or seed treatment: Harvest disease-free seeds or sterilize seeds by soaking in warm water at 50°C for 20 minutes. For seed dressing, 50% thiram or DT wettable powder, with 0.4% of seed weight. Soil treatment: 40% thiram WP or 40% pentachloro nitrobenzene powder, 8 to 10 grams per square meter, mixed with 30 to 40 kilograms of fine dry soil, sowed on the bed when sowing. Rotation: Intensive crops were promptly rehabilitated, with a gap of more than three years between the crops of non-cross families and intercropping with field crops. Chemical control: The beginning of onset of spraying, often spraying 75% chlorothalonil WP 600 times; 40% polysulfide suspension 600 times and 60% Duofu WP 600 times and so on. 8 to 10 days spray once, spray 1 to 2 times.
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