杨树溃疡病在我国分布广,危害重,主要危害苗木和幼树,新移栽的树木更为严重,轻则影响生长,重则造成大批树木枯死。 1、症状。病害主要发生在树干和主枝上,不仅危害苗木也能危害大树,病班多发生在树干基部0.2-2.5米高度范围内,感病植株多在皮孔边缘形成近圆形水泡状溃疡斑,初期极少,不明显,后变大呈典型水泡状,泡内充满淡褐色液体,水泡破裂,液体流出后遇空气变为黑褐色,并残留在病斑处。最后病斑干缩下陷,中央有一纵裂小缝。后期病班上长出许多黑色小点。通常粗皮树种不形成水泡,仅树皮下变褐腐烂,并流出红褐色液体,光皮树种水泡型症状明显。 2、发病规律。病菌以菌丝在树木病皮内越冬,树皮上常带菌。在廊坊、北京一带4月上旬开始发病,多发生 Poplar canker disease is widely distributed in our country, endangered, the main damage to seedlings and saplings, the new transplanted trees are more serious, ranging from the impact of growth, while causing a large number of dead trees. 1, symptoms. Disease occurs mainly in the trunk and the main branch, not only endanger the seedlings can also harm trees, disease classes occur in the base of the trunk 0.2-2.5 m height range, susceptible plants in the skin near the edge of the formation of nearly circular blister-like ulcer spots , The initial very few, not obvious, after the larger into a typical blisters, bubble filled with light brown liquid, blisters rupture, the liquid flows out of the air into a dark brown, and remain in the lesion. Finally, dry shrinkage subsidence, there is a central longitudinal cracks. Post-sick class grow many black dots. Usually bark species do not form blisters, only brown under the bark rot, and out of red-brown liquid, light-skin tree blisters obvious symptoms. 2, the incidence of law. Pathogens to mycelium in the winter tree bark, bark often carrying bacteria. In Langfang, Beijing began in early April onset, occurred