核桃炭疽病病原菌越冬方式及场所的研究

Overwintering forms and sites of the pathogen of walnut anthracnose

为明确河北省邢台市核桃炭疽病的越冬方式及越冬场所,于2018年12月和2019年3月越冬季节采集核桃树上发病的带芽枝条、带果柄果实、落果、落叶以及林下土壤,观察子实体着生情况,测定越冬子实体内孢子萌发率,对采集的组织以及土壤进行室内病原菌的分离培养。结果表明,核桃炭疽病病原菌可以子实体的形式在树上果壳和落果上越冬,越冬后子实体萌发率分别达96.82%,94.36%。该病菌也可以菌丝体的形式在果壳、果仁、果柄、芽鳞、枝条、落果果壳、落果果仁中越冬,越冬后病原菌分离率达60%~82%,少数可以在叶柄中越冬,越冬后分离率为27.59%。土壤也是其重要越冬场所,1 g土壤中病原菌数量为2.0×10^5个。

In order to clarify the overwintering forms and sites of the pathogen of walnut anthracnose in Xingtai city,Hebei province,the branches with bud,fruits with stalks,fallen fruits,fallen leaves and underground soil of walnut trees with anthracnose were collected during the overwintering season from December 2018 to March 2019.The fruiting body was observed,the conidia germination rate in overwintering fruiting bodies was determined,and the collected tissues and soil were isolated and cultured in the laboratory.The results showed that the pathogen of walnut anthracnose could overwinter on dropped fruit or husk on the tree in the form of fruiting body,and the germination rate of fruiting body after overwintering reached 96.82%and 94.36%respectively.The pathogen could also overwinter in the form of mycelium in the husk on the tree,the tree nuts,fruit stalk on the tree,bud scale,branches,husk of dropped fruit,and kernel of dropped fruit,the isolation rate of pathogen after overwintering reaching 60%-82%,while a few can overwinter in the petiole,and the isolation rate after overwintering was 27.59%.Soil was also an important overwinter site,and the number of pathogens in 1g soil was 2.0×10^5.