在春、夏两季气候冷凉、潮湿的国家,苹果黑星病发生危害最重。由于此病直接影响苹果的质量,果个及产量,加之喷药的花费,因而常造成严重的经济损失。有的年份,此病可使苹果减产70%以上,甚至造成苹果绝收。目前最重要的问题是减少这种病菌的初次侵染源和再侵染。如果能减少初次侵染源,就会大大地减少病菌的无性繁殖。在苹果树落叶前,施 In the spring and summer, the climate is cold and humid, damp countries, Apple scab is most harmful. As the disease directly affects the quality of apple, fruit and yield, coupled with the cost of spraying, which often cause serious economic losses. In some years, the disease can reduce the production of apples more than 70%, or even cause apple harvest. The most important issue at the moment is to reduce the initial infestation and reinfection of this bacterium. If you can reduce the initial source of infection, it will greatly reduce the vegetative propagation of bacteria. Before the apple tree leaves, Shi