Are species concepts outdated for fungi? Intraspecific variation in plant-pathogenic fungi illustrates the need for subspecific categorization.

Abstract Precise naming of a species is very important for phytopathogenic fungi because names may carry key information for the management of the fungal diseases. Naming fungal species based on morphological traits or biological properties is outdated and unreliable. This chapter provides the classification of some plant pathogenic fungi including Rhizoctonia solani, Colletotrichum, Fusarium oxysporum, and Verticillum based on morphological, pathogenicity, molecular and phylogenetic analysis. Debate on species identification is no longer a question of being in favour of 'splitters' rather than of 'lumpers', but defining phytopathogenic species is particularly complicated and requires further consideration of subspecific categorizations.