Cankers are diseased areas of the bark. Many different kinds of fungi and a few bacteria may cause them. The outer bark may appear abnormal. Inner bark is brown and discolored. In time, the bark may fall off. Leaves beyond the canker may yellow, scorch or die. Usually canker-causing pathogens can infect only hosts that have been injured or stressed. Trees in decline often lose branches to cankers. Management of canker disease includes avoiding unnecessary injuries and knowing and supplying the maintenance needs of the host to reduce stress. Prune out diseased branches well below the visible infection. After each cut, disinfect pruning tools with rubbing alcohol or 10 percent household chlorine bleach in water. With Rhizoctonia/Phoma canker or “die back,” stems and leaves may become blackened or blighted. Shoots beyond the necrotic area wilt and die. Remove severely affected plants. It may be necessary to increase air circulation by pruning overhanging shrubs and improve drainage by amending soil.