A fungus that resembles Chrysoporthe sp. was found associated with Eucalyptus mini-stumps in clonal mini-gardens in Brazil causing severe losses. The symptoms observed were wilt that evolves into partial or complete drying and death of the canopy, and lesion in the xylem of the mini-stumps. The primary objectives of this research were (i) to determine the causal agent of the wilt disease using morphological and molecular analyses; (ii) to assess the pathogenicity of the isolates on various commercial clones of Eucalyptus; and (iii) to evaluate the impact of temperature on the pathogen’s development. Through phylogenetic analyses of sequences from the Internal Transcribed Spacer, actin, and β-tubulin genes, Chrysoporthe cubensis was identified as the causal agent responsible for the wilt disease. All six tested Eucalyptus clones exhibited susceptibility to the pathogen, with clone CNB 007 demonstrating higher susceptibility and clones CNB 005 and CNB 030 displaying comparatively lower susceptibility. Furthermore, the development of the isolates varied depending on the Eucalyptus clone, with higher temperatures favouring pathogen growth. Notably, the less susceptible clones exhibited greater sensitivity to elevated temperatures compared to the more susceptible ones. This study represents the first report of C. cubensis causing wilt disease on Eucalyptus mini-stumps worldwide.

一种类似于Chrysoporthe sp的真菌。被发现与巴西克隆迷你花园中的桉树迷你树桩有关，造成严重损失。观察到的症状是枯萎，逐渐演变成树冠部分或完全干燥和死亡，以及小树桩木质部的病变。本研究的主要目标是 (i) 通过形态学和分子分析确定枯萎病的致病因子； (ii) 评估分离株对桉树各种商业克隆的致病性； (iii) 评估温度对病原体发育的影响。通过对内转录间隔区、肌动蛋白和 β-微管蛋白基因的序列进行系统发育分析，Chrysoporthe Cubansis被确定为导致枯萎病的病原体。所有六个测试的桉树克隆都表现出对该病原体的敏感性，克隆 CNB 007 表现出较高的敏感性，克隆 CNB 005 和 CNB 030 表现出相对较低的敏感性。此外，分离株的发育因桉树克隆而异，较高的温度有利于病原体的生长。值得注意的是，与更敏感的克隆相比，不太敏感的克隆对高温表现出更高的敏感性。这项研究是首次报道C.cubensis在全球范围内引起桉树迷你树桩枯萎病。