核桃基腐病病菌越冬场所试验研究

Experimental Study on Overwintering Sites of Walnut Stalk Rot Pathogens

通过采集病株茎基部土壤、腐烂病斑组织、病株上健康树皮、枝条、越冬芽,无病株主干树皮、枝条、越冬芽及落叶、落果等,利用大麻籽、黄瓜、土豆诱发土壤中病原菌,采用选择性培养基对疑似越冬器官组织进行病原菌的分离、培养、纯化及鉴定,并将分离物再接种。结果表明,病株根际土壤通过诱集分离出寡雄腐霉和镰孢霉,其中黄瓜片分离腐霉病菌的比率最高,达78.5%;从核桃腐烂病斑上分离到镰孢霉、链格孢菌及少量腐霉病菌;病株健康部位及无病株的树皮、枝条、越冬芽、落叶等器官均未分离到寡雄腐霉菌。对分离物的致病性测定结果表明,病田土壤是病原菌的主要越冬场所,其次也可在病组织中越冬存活。

By collecting soils of stem base of diseased plants,rot lesions,healthy tree barks,branches,o-verwintering buds from diseased plants,and tree barks,twigs,buds from healthy plants,fallen leaves,fallen fruits,etc,the hempseeds,cucumbers and potatoes were used to induce pathogens in the soil,the suspected overwintering tissues and organs were isolated cultured,purified and identified.The results indicated that P ythium oligandrum and Fusarium were obtained from soils of stem base of diseased plants,separation rate of P ythium pathogen from cucumber slices was the highest,reaching 78.5%.Fusarium ,Alternaria spp.and a little P ythium pathogen were isolated from Walnut rot scab.P ythium oligandrum was not got-ten in both healthy tree barks,branches,overwintering buds of diseased plants and these Parts of healthy plants,including fallen leaves,etc.Pathogenicity tests were performed with isolations and it showed that soils from diseased fields were main overwintering sites of walnut pathogens,secondly the pathogen also can overwinter in diseased plants.