Importance
Anthracnose, caused by the fungus Elsinoe veneta, causes severe damage each year to blackberries, to purple and black raspberries and to a much lesser extent, to red raspberries in Kentucky. When left to develop unchecked, anthracnose can significantly reduce overall yields as well as limit the longevity of bramble plantings.

Symptoms
Anthracnose can be present on both current and second-year canes. Initially, infected canes develop circular, light gray spots about 1/8 inch in diameter. Later, these spots enlarge, become sunken, and develop a purplish border with a light gray center. Spots often grow together to form large cankers, especially on older canes. Severely infected canes may be girdled or cracked, thus reducing the supply of water and mineral nutrients to the top. When this situation occurs, the fruit associated with the diseased canes often ripen abnormally and/or "dry-up" before maturation. The abnormal berries may have an "off" flavor.
The anthracnose fungus can also cause similar symptoms to on the leaves. Leaf spots are at first yellowish, turning to a distinct light gray with a red-purple border. Spots are about 1/16 inch in diameter. Leaf tissue showing anthracnose infection often drops out, leaving holes in the leaves called "shot holes." Only rarely does foliar anthracnose result in significant defoliation.
Cane blight and spur blight, two other potentially serious raspberry diseases, are also caused by fungi which can produce cane cankers like anthracnose. Although the symptoms can sometimes be confused these are distinctly different but less common diseases. Control measures are similar, however.

Disease Cycle
The anthracnose fungus overwinters primarily in old, infected canes produced the previous season. Primary infection in the spring occurs when spores (produced in lesions in these canes) are spread by splashing rain and wind to susceptible tissue. Once infection has occurred and the fungus is established, the disease continues to spread as additional spores are produced in what is known as the secondary disease cycle. Generally, severe disease is favored by prolonged wet weather during the growing season.

Control
Since the anthracnose fungus overwinters in old infected tissue, sanitation is important for effective disease management. Before setting new plants, cut off and burn to below ground level the stubs of old canes attached to the young plants. This procedure limits the infection of new shoots by any anthracnose that may be present in the old canes. In addition, remove and destroy old fruiting canes after harvest to reduce overwintering inoculum levels of the fungus.
Fungicide sprays can supplement sanitation for control of anthracnose. Generally, a delayed dormant application of liquid lime sulfur (10-12 gal per 100 gal dilute spray) is essential for good disease control. Although red raspberries are less likely to be seriously damaged by anthracnose than black or purple varieties, sprays should be applied if the planting has a history of anthracnose. Completely cover all canes with the fungicide to receive the spray's maximum benefit. Timing is also important as sprays applied after new shoots are 3/4 inch long may "burn" the leaves. This treatment will also aid in controlling spur blight and cane blight.
In severe disease situations, additional sprays may be required for acceptable disease control in new canes, even after harvest. However, in most cases, good disease control early in the season will reduce the need for later sprays. For a listing of additional fungicides and usage rates, consult Cooperative Extension publications, ID-94, "Small Fruit and Grape Spray Guide" or ID-21, "Disease and Insect Control Program for Home Grown Fruit in Kentucky".