As the spots enlarge they become darker in color and sunken, but remain circular in shape. The tissue beneath the spots is spongy. As the spots continue to develop, small bumps or cushions are formed in the centers. These bumps contain spores. Although the spots enlarge slowly, other rot-producing fungi may enter the damaged tissue and cause rapid rotting.
Sanitation is extremely important when trying to control apple anthracnose.
Cankered branches should be removed as soon as they are noticed. Do not wait until the dormant season to do this type of pruning. Cankers on large branches should be cut out during dry weather and treated with a registered fungicides. Check with your local WSU Cooperative Extension office for chemical control recommendations. By Roy Davidson, Jr., former Agricultural Research Technologist, and Ralph S. Byther, Extension Plant Pathologist, WSU Puyallup Research Center.