In the brambles, it is most serious on black raspberries, but can also occur on red and purple raspberries. Blackberries vary in how susceptible they are to this disease. Loganberry is highly resistant and boysenberry is highly susceptible. It is common in the northern half of the United States and on the Pacific Coast. Symptoms are most noticeable in hot, dry weather, and plants may look better in cool, fall weather.
Symptoms begin at the bottom of the canes and work up.
Leaves on new canes become pale green, then yellow in midsummer. Leaves may drop early. On second-year canes, fewer leaves are made. Beginning at the bottom of the cane and progressing upwards, the leaves become yellow, wilt, and fall off. Symptoms may be on only one side of the cane.