果实套袋可有效防止农药污染 ,提高果品质量 ,是目前生产无公害果品的有效途径。但近几年套袋苹果苦痘病大发生 ,并有逐年加重的趋势。1　套袋苹果苦痘病的发生原因1 1　化肥施用不当。近几年由于种植者不能科学施肥 ,尤其是氮、磷、钾高浓度复合肥和氯化钾、硫酸铵等酸性肥料 Fruit bagging can effectively prevent pesticide pollution and improve fruit quality, which is an effective way to produce pollution-free fruit products. But in recent years bagging apple bitter pox disease occurred, and there is a trend of increasing year by year. 1 bagging apple bitter pit disease causes 1 1 improper use of chemical fertilizers. In recent years due to growers can not be scientific fertilization, especially nitrogen, phosphorus, potassium and high concentrations of potassium chloride, ammonium sulfate and other acidic fertilizer