Phomopsis Cane, Leaf Spot, and Fruit Rot Fruit Pathology Penn State Department of Plant Pathology Jim Travis, Jo Rytter and Ken Hickey Phomopsis Cane, Leaf Spot, and Fruit Rot Phomopsis cane, leaf spot, and fruit rot, is widely distributed in vineyards. The disease can weaken vines, reduce yields and lower fruit quality. This disease was often the first disease of the growing season to appear in the vineyard. Infected rachises and shoots develop black, elongated lesions which often split the green tissue.
Numerous lesions give the surface a blackened, scabby appearance.
Leaf lesions often are numerous with brown or black brown coloration and become covered with black, pimple-like fruiting bodies. These infections usually do not become visible until late summer. When infections on shoots are numerous, they often run together and form dark blotches that crack. Cluster stems can blight and become brittle if infections are high. These clusters usually break and the fruit is lost.