北京地区桃树腐烂病的发生与诱因

1960—62年初步調查发現:桃树腐烂病疤主要分布在主干与主枝上,其中主枝基部(五(木义)骨)占60％;病疤多为西南向;流胶为发病后的共同表現;病害可深入皮层与木质部。各主要栽培品种均能感病,以大久保等最重,士蒼与耐寒品种病輕。病菌可自剪口、冻伤、虫伤等处侵入。3—10月田間接种均能发病,潛育期4—10天,以春季較短。病害每年自3月开始发生,3—5月最为严重,以后随树势生长旺盛,病害发展卽受限制。冻害为主要誘因,凡栽培不当如肥、水过多和过晚,以及与秋菜間作等促使徒长或延期休眠而誘发冻害者,均能誘致腐烂病,改进以上栽培管理,提高抗冻、抗病力是防治腐烂病的根本途径。

THE OCCURRENCE AND PREDISPOSITION OF PEACH CANKER IN THE VICINITY OF PEKING

The peach canker which caused by a species of Cytospora is severe in the vicinity of Peking. Field survey revealed that about 60 per cent of the cankers occurred on the basal part of the twigs and upper part of the trunk or of the collar. Most of the cankers occurred on the southwest sides of the trees. The cankers initiate their activities usually in the late march and ceased to develop in May or early June. Henceforth, a greater healing power halts the development of the disease. The pathogen entered into the tree mainly through winter injuries, pruning wounds, and insect injuries. Winter injury and incorrect cultural practices are considered to be the most portant inducing factors of the disease.