苦痘病的发病原因是果实内缺钙。主要原因是土壤缺钙,树体吸收量不足;铵态氮肥、钾肥施用时间不当,用量过多,影响了树体对土壤中钙的吸收;树势偏旺,果实生长过大,使果实内钙浓度过低。 Bitter pit disease is caused by calcium deficiency in the fruit. The main reason is lack of calcium in the soil and insufficient absorption of the tree body. The ammonium nitrogen fertilizer and potassium fertilizer are applied in an improper time and in too much dosage, which affects the calcium absorption in the soil by the tree body. When the tree vigor is too strong and the fruit grows too large, Calcium concentration is too low.