【摘要】 苹果树腐烂病(Valsa mali Miyabe et Yamada)是我国北部苹果产区的主要病害之一,每每在周期性冻害之后盛发,一般在管理粗放、树势衰弱的果园为害严重。在早期的工作中,试图用常规研究方法探索病菌侵入的集中时期,采用适期喷布保护剂防止病菌侵入的方法来预防发病,未获预期的结果。1961—1963年,作者等继续研究侵染问题。在5—9月间果树生长季内,采集外观无病的健康苹果枝条,置-10℃以下环境中冻死,涂石硫合剂杀死枝条上可能附留的孢子,隔绝外来侵染,在室温下插湿砂盘中保持枝条不乾。经一定时间,树皮腐解,呈现腐烂病变特徵,并产生分生孢子器。取分生孢子接种,能致病。试验证明,正常的苹果树皮上带有潜伏病菌,它在寄主失却抗性时扩展。苹果树腐烂病菌具潜伏侵染特点。幼树和成年树同龄枝条带菌枝率无显著差异。2—5年枝,带菌枝率随枝龄增长而增高。辽宁、河北、山东、山西、河南、安徽、湖北等省苹果枝条都带潜伏病菌。文中讨论了潜伏侵染在腐烂病研究和防治上的意义。作者等强调了增强树势,提高抗扩展能力,应作为基本的防治措施。药剂防治的研究应从保护的应用研究改变为筛选具有铲除效能的杀菌剂或内吸杀菌剂。文中还提到探索生物防治的可能性和侵染研究的方法问题。更多还原

【Abstract】 Valsa canker(Valsa mali Miyabe et Yamada)is one of the most serious dis-eases of apple in North China.Generally,it affects the weak bearing trees andcauses catastrophic damage after periodical freezing.In early works,the authors attempted to search for the period of infectionand to control with certain protective fungicides,but all the attempts failed.Inthe years from 1961 to 1963,the authors concentrated the work on the studies ofthe nature of infection of the causal fungus.During the growing season,fromMay to September,the authors collected apparently healthy apple twigs and smallbranches,killed them by freezing below-10℃.After surface sterilization withlime sulfur,these shortened twigs were placed in pans half filled with wet sandin order to keep them moistened.These works were undertaken in the green hou-ses or growth chambers where the Valsa spores were absent.After a specificperiod,the bark of some twigs decayed showing the characteristic Valsa cankerappearance,and Valsa pycnidia was produced.Inoculating the healthy appletwig with spores from this pycnidia caused the characteristic Valsa canker.Thus,it is demonstrated that latent infection of Valsa mali occurred in the Valsabark of apple.The percentages of Valsa latent infection of twigs of the same age of bothyoung and old trees were similar.In the twigs two to five years old,the percen-tages of latent infection increased with the age.Valsa latent infections in apple barks are widespread in distribution,theyoccurred not only in the canker disease area of the Provinces Liaoning,Hopei,Shantung and Shansi,but also in the non-canker diseased Provinces Anhui andHonan,even in Hupei,a province of the Yangtze Valley.The authors discussed the significance of the latent infection of Valsa cankerfungus in relation to the further research works and control measures of cankerdisease.The maintenance of tree vigor is emphasized as the fundamental measureof the canker control.The work on the chemical control of Valsa canker syste-mic fungicides,especially those with endotherapeutic activity,was regarded asthe most important.The significance of the biological control of Valsa canker ofapple was also indicated.更多还原