一、病毒病白菜病毒病是白菜三大病害之一，一般年份发病率为３％～３０％，病重地块可达８０％以上。幼苗在七叶以前易感病，病株多不能包心结球。后期发病植株受害轻，所以发病越早受害越重。苗期高温干旱，病毒病发生重。早播发病重，晚播发病轻。症状：幼苗受害时心叶上出 First, the virus disease cabbage virus disease is one of the three major diseases cabbage, the general year incidence of 3% to 30%, up to 80% of the disease block. Seedlings are susceptible to disease before the seven-leaf, the disease can not be more than the ball wrapped. Post-disease plants suffer light, so the earlier the onset of the more serious victims. Seedling heat and drought, severe viral disease. Early onset of serious illness, late sowing light. Symptoms: When the seedling leaves the heart leaves