Taxonomic Reevaluation of Blackwellomyces Isolates Preserved in Korean Agricultural Culture Collection and Description of Two New Species.

Blackwellomyces is a genus of entomopathogenic fungi in the family Cordycipitaceae (Hypocreales, Sordariomycetes, Ascomycota) that primarily infects arthropod larvae, particularly those of Lepidoptera. Despite its ecological significance, this genus remains poorly studied in Korea. During the re-identification of Korean Cordyceps sensu lato isolates preserved in the Korean Agricultural Culture Collection (KACC), 12 strains were found to belong to the genus Blackwellomyces. Accordingly, this study aimed to accurately identify and clarify the taxonomic status of these isolates. The 12 Blackwellomyces strains were identified using molecular markers, including the internal transcribed spacer (ITS), large subunit rDNA (LSU), translation elongation factor 1-alpha (TEF), and the largest (RPB1) and second-largest (RPB2) subunits of RNA polymerase II. Phylogenetic analyses based on multilocus sequence data revealed that the isolates formed two distinct clades, which were further supported by morphological observations, representing novel species within the genus. Consequently, two new species, Blackwellomyces koreensis sp. nov. and Blackwellomyces larvicola sp. nov., are described from Korea.