苹果白粉病是苹果树较难防治的常发性病害之一,在各苹果产区普遍发生,特别是近年来病害的发生日趋加重。被害新梢生长受到很大影响,不但影响当年产量,而且不利于叶芽与花芽的分化,从而降低第二年的产量。少数严重受害的果树,叶片提前枯死脱落引起新梢干枯死亡,严重影响树势,缩短结果年限。发病原因: Apple powdery mildew is one of the most common diseases that apple trees are hard to prevent and control. It occurs in every apple producing area especially in recent years. Victim shoot growth has been greatly affected, not only affect the current production, but also conducive to the differentiation of leaf buds and flower buds, thereby reducing the second year of production. A few serious victims of fruit trees, leaves died in advance died off shoot death, seriously affecting the tree vigor and shorten the results of life. Causes: