梨树疫腐病又叫颁腐病,是近年来在河北省中南部出现的一种新病害,特别是遭受水灾的梨园发病重、传播快、幼树死亡率高,是一种毁灭性病害。 一、病原及传播。病原是土壤习居菌侵染致病。病原菌随地面流水传播。树干基部嫁接口、机械伤冻伤是病菌的主要侵染点。 二、发病症状。该病主要发生在幼树主干基部,砧穗接口以上。病部树皮呈黑褐色,皮层组织逐渐坏死,干缩凹陷,当病斑绕树干一周时,破坏形成层,造成全树死亡。病树一年生枝衰弱,秋季叶片变红,逐渐变褐而脱落。果实受害后,产生不明显褐斑,部 Pear blight rot disease, also known as rot disease, is a new disease in central and southern Hebei Province in recent years, especially in flood-prone pear orchard disease, rapid transmission, saplings high mortality rate is a devastating disease . First, the pathogen and spread. Pathogen is caused by soil habitat infection. Pathogen spread with the ground water. Trunk base grafting, mechanical injury frostbite is the main infection of bacteria. Second, the incidence of symptoms. The disease occurs mainly in the sapling trunk base, scion spike interface above. Sick bark was dark brown, cortical tissue necrosis, shrinkage depression, when the lesion around the trunk a week, the destruction of the formation of layers, resulting in death of the whole tree. Diseased tree annual branches weak, autumn leaves turn red, gradually brown and fall off. Fruit damage, have no obvious brown spots, Ministry