Powdery mildews (Erysiphaceae) are obligate fungal pathogens that infect over 10,000 plant taxa worldwide. Oaks (Quercus spp.) are a particularly important group of hosts due to their ecological and economic value. Recent molecular work has revealed that species infecting North American oaks are more diverse and host-specific than previously recognized. Here, we describe Erysiphe quercus-palustris sp. nov., collected on Quercus palustris in North Carolina, and clarify the placement of the previously described species E. abbreviata. Phylogenetic analyses support the separation of the new species from the main “North American” Erysiphe clade whose species are typically characterized by aerial hyphae, a feature absent in E. quercus-palustris. This study contributes to the growing evidence of cryptic diversity within oak-infecting powdery mildews and underscores the importance of continued taxonomic and phylogenetic research on pathogens of ecologically important hosts.
Shaw et al. (Thu,) studied this question.