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）属的一种植物是重要的植物病原真菌，在热带和亚热带气候中会严重破坏植物作物。目前，Calonectria叶片枯萎病是巴西桉树栽培的主要障碍之一，并且各种Calonectria物种都与该病有关。由于以前的大多数鉴定仅基于形态特征，因此许多已发表的文献都需要重新评估。因此，本研究的目的是确定和确定桉树中所存在物种之间的系统发育关系。巴西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。根据从土壤和人工林感染的桉树叶片样品的大量采集，系统发育推断揭示了钙。翼龙复合体是巴西桉树人工林中最常见的物种复合体。通过阐明Ca中的分类单元。pteridis，钙。cylindrospora和钙。烛台物种复合体，确定了20种新的Calonectria物种，并为Calonectria提供了一个新名称圆柱状大孢子虫为Ca。pseudopteridis。