Integrative Taxonomy Reveals the First Record of Diaporthe manihotia in Russia and Resolves the Status of Diaporthe betae Within the D. manihotia Species Complex

Diaporthe comprises widespread, economically significant fungi associated with diverse plant hosts. The genus exhibits overestimated species diversity, with numerous new taxa described annually. Recently, an integrative approach combining multilocus phylogeny with Genealogical Concordance Phylogenetic Species Recognition (GCPSR), phylogenetic network analysis, and coalescent‐based methods (PTP, mPTP) has been adopted for reliable species delimitation in Diaporthe . This study applied such approach to identify three Diaporthe strains isolated from Chenopodium album in the Russian Far East (Amur region) in 2023. Multilocus phylogenetic analysis of ITS, cal , his3 , tef1 and tub2 placed the strains within a well‐supported clade corresponding to Diaporthe betae in the Diaporthe ganjae species complex. Integrative analysis reliably identified the strains as members of this complex. Furthermore D. betae was found to be redundantly described and conspecific with other species in this complex. Taxonomic re‐evaluation revealed that the name D. ganjae was erroneously prioritized for this complex. According to the International Code of Nomenclature for algae, fungi, and plants, the correct priority name is D. manihotia . Consequently, our strains were reliably identified as D. manihotia . Accordingly, we propose synonymization of D. betae , D. compacta , D. ganjae , and D. sambucusii under D. manihotia . This study provides the first report of D. manihotia in Russia and the first record of C. album as a host for this species.