Black rot, Guignardia bidwelli, is one of the most serious diseases of grapes in the eastern United States.
Botrytis bunch rot, or gray mold, exists in all vineyards worldwide. This disease is caused by the fungus Botrytis cinerea and is commonly associated with the decay of ripe or nearly ripe grapes.
Crown gall, Agrobacterium tumefaciens, is characterized by galls or overgrowths that form on the roots, trunk, and arms of grape vines. V. vinifera are more susceptible than V. labrusca varieties.
Downy mildew, Plasmopara viticola, can infect berries, leaves and young shoots. It occurs wherever it is wet and warm during the growing season.
Phomopsis cane, leaf spot, and fruit rot are widely distributed in vineyards. The disease can weaken vines, reduce yields, and lower fruit quality.
Powdery mildew, caused by the fungus Uncinula necator, can be found in most areas of the world where grapes are grown.
