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一、分布与危害白粉病是世界上分布很广的一类病害,在我区每年均有不同程度发生。经初步调查,已发现杨树,苹果、枸杞、刺槐等数十种。病害主要发生在叶片和嫩枝梢上。小苗、大树上都可发生,但以幼苗受害为重。如1965年灵武种苗场和1978年银川苗木场,刺槐幼苗上都发生了自粉病,发病率高达100%,叶面上布满了灰白色粉状物,即病菌
First, the distribution and hazards Powdery mildew is a type of disease in the world is widely distributed, in my area every year, varying degrees of occurrence. After a preliminary investigation, poplar, apple, Chinese wolfberry, acacia and other dozens have been found. Diseases mainly occur on leaves and shoots. Seedlings, trees can occur, but the seedling victims as the most important. Such as Lingwu seedling field in 1965 and 1978 Yinchuan seedling field, locust seedlings have occurred on the powdery mildew, the incidence of up to 100%, the foliage covered with an off-white powder, that bacteria