SUSCEPTIBILITY OF AMERICAN, EUROPEAN, AND INTERSPECIFIC HYBRID GRAPE CULTIVARS TO THE FUNGUS SEPTORIA-AMPELINA

European Vitis vinifera L. (four cultivars); interspecific hybrid (sev en cultivars); and American V. aestivalis Michx. (one cultivar), V. la brusca L. (three cultivars), and V. rotundifolia Michx. (two cultivars ) grapevines were tested for susceptibility to septoria leaf spot dise ase. V. rotundifolia cultivars Cowart and Fry exhibited hypersensitive -type resistance. All other American, European, and hybrid cultivars t ested were susceptible with varying levels of disease severity. Cultiv ars with little (e.g., interspecific hybrid) or no (e.g., European) V. labrusca L. heritage were more susceptible to septoria leaf spot than American V. labrusca cultivars.