梨黑星病是我国梨区的最重要的病害。危害梨树的梢、叶、花、果和嫩芽,常造成落叶,树势衰弱,使产量和品质大幅度下降。在我省的条件下,梨树黑星病的发生,具有以下特点:(一)春季发病的早晚,与冬春的雨雪多少有密切关系。黑星病的病原菌,多以菌丝在发病的枝梢芽内和枝条上越冬。梨芽萌动时,即开始活动,到芽鳞开绽时,就会在嫩芽或花朵上危害。一般冬春雨雪多,湿度大的年份,发病早而重。梨芽萌动后迂雨,病菌就能传播。在空气湿度达到70%以上,叶面有露时,病菌就会侵染。(二)夏季雨水多少,是能否发生流行的重要条件.在降雨量多的情况下,病菌随时都能传播,侵染,由春季的点片发生,而至蔓延成灾.(三)品种间的发病程度有一定的差别。我省栽培的梨树品种中,以鸭梨,黄县 Pear scab is the most important disease in pear area of ​​our country. Pests endanger the shoots, leaves, flowers, fruit and shoots, often resulting in deciduous trees, frail weakness, the yield and quality dropped significantly. In the province under the conditions of the occurrence of pear scab, has the following characteristics: (a) the onset of spring sooner or later, and the winter and spring rain and snow are closely related. Scab pathogens, mostly in the pathogenesis of shoots shoots and branches overwintering. Pear bud germination, that is, activity began to Bud scales bloom, it will endanger the buds or flowers. General snow winter and spring, wet years, the incidence of early and heavy. Pear sprouting after rain, bacteria can spread. In the air humidity reaches more than 70%, leaves exposed, the bacteria will infect. (B) how much rain in the summer, is an important prerequisite for the prevalence in the case of large rainfall, the bacteria can spread at any time, infection, from the spring of the film occurred, but to spread into disaster. The incidence of a certain difference between. Pear cultivated in our province varieties to pear, yellow county