Abstract
Botanical gardens host diverse plant assemblages that provide valuable opportunities to study fungal biodiversity and plant–fungal interactions. Powdery mildews ( Erysiphaceae ) are common pathogens in these settings, yet little is known about how they co‐occur with culturable fungi present on infected leaves. To document fungi recovered from infected tissue, we surveyed powdery mildew infections at the JC Raulston Arboretum, which is part of North Carolina State University. We identified the powdery mildew species present and the fungi that could be cultured from the infected phyllosphere. Eighteen powdery mildew species representing three genera were documented and confirmed through morphological and molecular methods. Using a dilution‐to‐extinction culturing approach, we recovered 147 isolates corresponding to 57 fungal species across 36 genera. Several genera including Aspergillus and Cladosporium were repeatedly recovered from powdery mildew‐infected leaves, and six isolates represent potentially novel lineages. Several of these genera have previously been shown to possess biological control potential against powdery mildew. These findings demonstrate that botanical gardens harbor rich, underexplored fungal diversity and that powdery mildew–infected tissues provide access to a broad community of co‐occurring fungi. Our results highlight the potential of culture‐based surveys in botanical gardens to uncover novel fungal taxa and identify candidate biological control agents for powdery mildew management.