Occurrence Regularity and Influencing Factors of Pear Spot Disease in Field

Symptoms, occurrence regularity and influencing factors of the spot disease in pear leaf were investigated and analyzed through field tracking and fixed observation.The results showed that the pear spots disease performed with small spot and large quantity in field.The spots could appear in leaf surface, vein and petiole, and made the leaves become yellow-green at the middle-late stage.The disease level would be higher during years with more rainy days or heavier rain, and be more gentle on the contrary.The disease degree varied among different pear species, which was lighter on Mixue, Mingfu, Huanghua and Qingxiang.Meanwhile, the disease degree was negatively correlated to the altitude with significant or very significant difference, and decreased as the height increasing.Within a flat ground orchard, pear leaves of the side rows showed more resistant to the spot disease.And among gardens, higher management level with the robust tree could greatly reduce the incidence and control the spreading tendency of the spot disease.