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POSTERS: Mycology II

P-400 - Characterization of Oklahoma grape vineyard mycoflora present during dormant season that contributes to disease epidemics during grape growing season

Tuesday, August 5, 2025
10:15 AM - 11:00 AM HST
Location: Exhibit Hall 3
Abstract Text:

Grape production requires proactive management of disease caused by fungi and fungus-like organisms for profitable yields. However, the fungal diseases limiting grape production in Oklahoma are poorly characterized. The objectives of this study were to improve grapevine management by identifying fungi present in dormant and actively growing grapevines in Oklahoma vineyards. A survey of nine vineyards in eight counties was conducted in 2024. Dormant and actively growing samples of leaves, berries, mummies, and canes were collected for pathogen analysis. Fungi were cultured and isolated from diseased tissues on ampicillin and streptomycin amended potato dextrose agar (APDA), and each unique isolate was subcultured onto PDA. More than 2000 fungal isolates were collected from more than ten grapevine varieties.  DNA extracted from isolates’ mycelia was used to amplify ITS, β-tubulin, Calmodulin, and TEF gene sequences. BLAST searches identified fungi such as Phyllosticta ampelicida, Eutypella vitis, Phaeoacremonium species,  Diplodia seriata, Botryosphaeria dothidea,  Diaporthe ampelina (synonym Phomopsis viticola) involved in black rot, Phomopsis, trunk decline diseases, and other grapevine-associated fungi of uncertain pathogenicity. These results are important for the identification of fungal species present during the dormant season that may contribute to disease epidemics during the grape production season.