The cankers are hard to detect as they are concealed by old, dead bark, which may become somewhat flattened. A cross section of the infected area may show a wedge-shaped area of darkened wood coming to a point in the center of the trunk. Symptoms of Eutypa dieback are apparent after the canker has become well established, perhaps 2 to 4 years after infection of the pruning wound. As new shoots develop on the trunk or arms above the cankered area, growth appears stunted and the internodes shortened. Symptoms are not readily seen until late spring because affected shoots are usually covered up by healthy shoots.
Infected leaves are small, yellow, and crinkled.
Symptoms on foliage of diseased arms become more extensive each year until eventually the diseased arm fails to produce shoots in the spring. Clusters on affected shoots may have a mixture of both large and small berries. The disease is caused by the fungus, Eutypa lata . This disease is entirely different from that reponsible for Phomopsis cane blight, leaf spot, and fruit rot. In winter, during rainfall or snow melt, fungal spores are released from fruiting structures on dead infected wood.