苹果干腐病发生与防治

根据1960—1961年的研究,苹果干腐病在辽宁省,每年从5月中旬到10月均能发生为害,6月分为发生发展的第一次高峯;8月下旬至9月上旬为第二次高峯。苹果干腐病的发生与气候条件有密切关系。干旱与积水均能诱发病害的发生,而干旱的影响最大。地势与发病亦有影响,低洼地发病较重。树势强弱与本病的发生有密切关系。栽培管理条件好,树势旺壮者,病势一般较轻。喷药保护树干有一定作用,彻底刮治病斑,再涂抹石灰硫磺合剂,效果很好。

STUDIES ON THE OCCURRENCE AND CONTROL OF TRUNK ROT OF APPLE TREE

Formerly trunk rot of apple (Botryosphaeria ribis Gross,et Dugger) was reported only occuring on young trees.Since 1957 it was noted to be one of the serious diseases on mature apple trees in the southern part of Liao-ning province,where the disease developed from the middle of May to the end of October.There were two peaks of development in a year (i.e.June and August),during which the cankers extended most rapidity.Wounds and lenticels were found to be the principal entrances of the fungus.The rate of infection reached 62.7% at the points where the bark was injured.Topography was also an influencing factor.Lim-sulfur spray proved to be fairly effective among the nine fungicides tested.Four applica-tions of lime-sulfur in the growing season reduced the trunk rot to less than 50%.Cuttingoff infected tissue or banks was considered as a less effective operation.