Diplodia was introduced by Montagne (1834) with D. mutila on bark of Populus nigra from France. However, its taxonomic history has been confusing for many years, particularly due to the controversy surrounding the holotype and the characters that define the type species of the genus (Phillips et al. 2013). Alves et al. (2004) examined the isotype of D. mutila and clarified the morphological status of the species and an emendment of the genus was later provided by Phillips et al. (2005). Since no ex-type, or authentic cultures, of any type specimen of D. mutila exits, Alves et al. (2014) designated an epitype and ex-epitype culture based on a collection from Populus alba in Portugal. Species in Diplodia are characterized by hyaline, aseptate and thick-walled conidia that may become pigmented and 1-septate either after or before discharge from the pycnidia (Phillips et al. 2013). They have a worldwide distribution and are known as pathogens, endophytes and saprophytes on a wide range of mainly woody hosts (Damm et al. 2007, Slippers & Wingfield 2007, Lazzizera et al. 2008, Laveau et al. 2009, Pérez et al. 2010, Phillips et al. 2012, Linaldeddu et al. 2013, Abdollahzadeh 2015). Some Diplodia species are important pathogens causing cankers, dieback, wilt, root diseases, leaf spots and shoot/tip blight on a variety of horticultural crops, such as D. corticola on oaks, D. sapinea on pines and D. mutila and D. seriata on apples (Alves et al. 2004, Trapman et al. 2008, Stanosz et al. 2009, Phillips et al. 2012, Úrbez-Torres et al. 2016, Ferreira et al. 2021). Although more than 1000 species epithets are listed in MycoBank and similar databases (Crous et al. 2004), DNA sequence data are available for a limited number of species. Currently, 28 species are recognised based mainly on the basis of molecular data and minor differences in conidial morphology (Phillips et al. 2013, Boonmee et al. 2021, Lee et al. 2021, Tennakoon et al. 2021, Zhang et al. 2021a).