防止白菜的病毒病、霜霉病和软腐病这三大白菜病害,是稳定白菜高产丰收的关键。一、白菜病毒病病叶皱缩不平,质脆,心叶扭曲,有的沿叶脉产生褐色坏死斑,味苦。早期受害往往不能结球。轻病株虽能结球,但叶球松散不实。植株发病愈早受害愈重。重病株矮缩,不包心。根系不发达,须根很少。防治措施:(一)农业防治适期晚播,特别是高温干旱时,不宜早播。重施有机肥,多用复合肥或磷钾肥,忌偏施氮肥。苗期浇水降温,坚持三水 To prevent the cabbage virus disease, downy mildew and soft rot diseases of these three cabbage, cabbage is the key to stabilizing high yield bumper. First, the cabbage virus disease leaves shrink wrinkles, crisp, distorted heart leaves, and some brown necrosis spots along the veins, bitter taste. Early victims often can not get the ball. Slightly ill although the ball can be a ball, but leaves loose loose. The earlier the plant is affected, the harder it is. Heavy sick dwarf, not heart. Roots underdeveloped, few fibrous roots. Prevention and control measures: (A) appropriate agricultural late sowing, especially when hot and humid, should not be sowed. Heavy organic fertilizer, fertilizer or phosphorus and potassium, bogey nitrogen fertilizer. Seedling water cooling, adhere to Sanshui