The genus Quambalaria includes several important pathogens of Eucalyptus and Corymbia spp., mainly those that cause leaf and shoot blight. The species Quambalaria eucalypti has been reported to be an aetiological agent of this disease in Brazil only in nurseries involved in the production of Eucalyptus minicuttings, where climatic conditions are more favourable for the pathogen. The aim of this study was to identify the pathogen that causes a similar disease in young Eucalyptus trees. For this, we used morphological characteristics, pathogenicity tests and DNA sequence data. Sequences of four isolates obtained from leaves and cankers were compared to 17 sequences deposited in GenBank. Twenty‐one isolates were subjected to multilocus analyses of internal transcribed spacer (ITS) and rDNA large subunit (LSU) sequence information. The resulting consensus tree showed that isolates in this study could be grouped with Q. eucalypti into one distinct clade, and the morphological characteristics were similar to those described in the literature. The pathogenicity was confirmed, and the pathogen was re‐isolated from inoculated plants, confirming Koch's postulates. This is the first record of Q. eucalypti causing leaf and shoot blight on young Eucalyptus plants in field conditions in Brazil. The presence of this disease in nurseries and its occurrence in the field is cause for alarm in Eucalyptus breeding programmes in Brazil.

中文翻译：

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巴西田间条件下年轻桉树植物中的桉树桉树的首次报道

Quambalaria属包括Eucalyptus和Corymbia spp。的几种重要病原体，主要是引起叶片枯萎和枯萎的病原体。据报道，巴西桉树种是该病的病原体，仅在涉及小型桉木生产的苗圃中才有，而那里的气候条件对该病原体更为有利。这项研究的目的是确定引起幼年桉树类似疾病的病原体树木。为此，我们使用了形态特征，致病性测试和DNA序列数据。将从叶片和鳞茎获得的四个分离株的序列与GenBank中保存的17个序列进行比较。对21个分离株进行了内部转录间隔区（ITS）和rDNA大亚基（LSU）序列信息的多基因座分析。生成的共有树表明，该研究中的分离株可以与桉树分为一组不同的分支，其形态特征与文献中描述的相似。确认了病原性，并从接种的植物中重新分离了病原体，这证实了科赫的假设。这是Q. eucalypti在幼年的桉树上引起叶片和茎叶枯萎的第一个记录。巴西的野外植物。该病在苗圃中的存在及其在野外的发生，引起了巴西桉树育种计划的警觉。