一、危害症状及程度病害主要发生在树干的1.5米以下,裂纹多在树干的东南面、南面、西南面,从树干基部开始,向上出现不等长度的裂缝,最长78cm,最短15.8cm,平均42.3cm,平均宽度2～3mm,大多深达木质部,平均发病率24.6%。二、发病原因杨树破腹病,一般发生在早春或晚秋,天气骤然变冷或变暖,气温忽高忽低,昼夜温差大时易诱发此病。生长后期,土壤水分过多,树木生长过快,木质部含水量过高,树干横向生长不均匀,也是导致幼树发生破腹病的重要原因。影响幼龄树破腹病的 First, the hazard symptoms and degree of disease occurs mainly in the trunk of 1.5 meters below the cracks in the trunk southeast, south, southwest, starting from the base of the trunk, there are upward cracks of different lengths, the longest 78cm, the shortest 15.8cm, Average 42.3cm, the average width of 2 ~ 3mm, mostly deep xylem, the average incidence of 24.6%. Second, the cause of the disease Poplar broken belly disease, usually occurs in early spring or late autumn, the weather suddenly chilled or warmer, the temperature fluctuated, the temperature difference between day and night is easy to induce the disease. Late growth stage, the soil is too much water, excessive growth of trees, xylem water content is too high, horizontal growth of uneven trunk is also an important reason leading to young belly breaking belly. Affect the young tree breaking belly disease