Objective Affected by industrial structure adjustment, tree aging and frequent frost damage, the occurrence of Apple Valsa Canker has become increasingly severe in Xinjiang, which seriously restricts the development of local apple industry. This study was conducted to clarify the occurrence status and dynamic regularity of Apple Valsa Canker in major apple-producing areas of Xinjiang, especially in Aksu region, and to provide a theoretical basis for integrated disease prevention and control.
Methods A combination of general field survey and fixed-point systematic monitoring was adopted to investigate the occurrence of Apple Valsa Canker in major apple-producing areas of Xinjiang and monitor its population dynamics in Aksu
Results There were significant differences in the severity of Apple Valsa Canker between Northern and Southern Xinjiang. The average incidence rate and disease index were 38.57% and 1.82 in Southern Xinjiang, while 70.74% and 3.29 in Northern Xinjiang, indicating the disease was obviously more severe in Northern Xinjiang. The disease resistance varied greatly among different apple cultivars. Red Fuji showed the highest average incidence rate (33.40%) and disease index (3.03), while Huashu had the mildest disease symptoms. Lesions expanded rapidly from April to May and reached the peak around May 20, and basically stopped expanding in early August.
Conclusion The occurrence of Apple Valsa Canker presented obvious regional differences, with more serious damage in Northern Xinjiang. Cultivar and tree vigor were key influencing factors, and Red Fuji was highly susceptible to the disease, as well as old and weak trees. In production, it is necessary to strengthen tree vigor cultivation, protect pruning wounds and prevent frost damage to reduce disease losses.
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