Introduction: Most grapevines are very susceptible to various fungal diseases. These diseases affect leaves, shoots, and fruit. Leaf diseases can drastically reduce photosynthesis, and, in extreme cases, can cause defoliation. Fungal diseases can render fruit unusable and can very easily cause severe losses in yield.
It is important to distinguish between the three broad categories of grapevines because of differences in susceptibility to fungal diseases. “Vinifera” refers to Vitis vinifera varieties, also known as the classic European winegrape: Chardonnay, Riesling, Merlot, Pinot Noir, Cabernet Sauvignon, and Thompson Seedless. American” refers to species of grapes native to North America, including Concord, Canadice, Einset, Delaware, Catawba, Niagara, and the winegrape Cayuga White. “Hybrid” refers to varieties of grapes that are crosses between vinifera and American grapes: Aurore, Chancellor, De Chaunac, Seyval, Vidal, Vignoles, Melody and the table grapes Interlaken, Himrod, Lakemont, and Romulus.