Species in the genus Calonectria (Hypocreales) represent an important group of plant pathogenic fungi that cause serious losses to plant crops in tropical and subtropical climates. Calonectria leaf blight is currently one of the main impediments to Eucalyptus cultivation in Brazil, and various species of Calonectria have been associated with this disease. Since most previous identifications were solely based on morphological characters, much of the published literature needs to be re-evaluated. The aim of this study was thus to identify and determine the phylogenetic relationships among species that occur in the Eucalyptus growing regions of Brazil by using partial sequences of the β-tubulin, calmodulin, translation elongation factor 1-α and histone H3 gene regions. Based on extensive collections from soil and infected eucalypt leaf samples from plantations, phylogenetic inference revealed the Ca. pteridis complex to be the most common species complex present in Eucalyptus plantations in Brazil. By elucidating taxa in the Ca. pteridis, Ca. cylindrospora and Ca. candelabra species complexes, 20 novel Calonectria species were identified, and a new name in Calonectria provided for Cylindrocladium macrosporum as Ca. pseudopteridis.

Calonectria ( Hypocreales ) 属中的物种代表了一组重要的植物病原真菌，它们对热带和亚热带气候下的植物作物造成严重损失。 Calonectria叶枯病是目前巴西桉树种植的主要障碍之一，多种Calonectria都与这种疾病有关。由于大多数以前的鉴定仅基于形态特征，因此许多已发表的文献需要重新评估。因此，本研究的目的是通过使用 β-微管蛋白、钙调蛋白、翻译延伸因子 1-α 和组蛋白 H3 基因区域的部分序列来识别和确定巴西桉树种植区物种之间的系统发育关系。根据对土壤和种植园受感染桉树叶样本的广泛收集，系统发育推断揭示了Ca。凤尾蕨复合体是巴西桉树种植园中最常见的物种复合体。通过阐明Ca中的分类群。蕨类植物， Ca 。圆柱孢子虫和Ca 。烛台物种复合体，鉴定出 20 个新的Calonectria物种，并在Calonectria中为Cylindrocladium macrosporum提供了一个新名称Ca。拟蕨属。