杨梅根腐病的早期诊断

掌握杨梅根腐病早期症状是取得既经济又有效的防治效果的基础。在调查该病害发生情况的基础上, 采用断根和接致病菌等方法模拟其早期症状。发现单株早期症状主要是:盲芽增多, 叶色变淡, 非正常落叶增加, 部分枯梢, 老干上抽生细小新梢复又枯死。根系的早期症状表现为部分细根和根瘤先枯死;多数树体的坡下侧根系先发病枯死。在诊断中还要区分枝叶病虫害和生理病害引起的症状。在群体(成片)发病的早期诊断中, 宜把成片的杨梅林看作是一棵大杨梅树 。单株发病死亡, 就是群体早期症状的开始。表2 参1

Early diagnosis of root rot in Chinese strawberry

Early diagnosis of root rot of Chinese strawberry could help achieve an effective and economic prevention effect.The research was carried out to investigate its occurrence conditions and the simulated (root cutting) symptoms . A single tree demonstrated such chief symptoms as an increase in blind buds , paleness of learves , increase in abnormal fallen leaves , as well as death of new tiny tips which grew on old trunks .The withering of some thin roots and root nodules were the early symptoms of root systems . Damaged roots mostly occurred at the lower part of hillside and withered before others .The symptoms caused by leaf pests and physiological diseases should be differentiated from those caused by root rot during diagnosis . It is suggested that a group of trees be regarded as a big tree in diagnosis , and the death of a sick single tree as initial symptoms of the group .