Cankers are caused by any of a number of different fungi and bacteria. They usually appear as discolored, sunken areas on a branch or on the main trunk, and often have sap oozing from them. As the organisms spread through the tissue, the cankers increase in size. If the cankers girdle the wood, the portion of the tree above the canker dies. Remove cankered branches by pruning off the branch at the trunk, or at least 6 inches below the canker. When the canker appears on the main trunk or a large branch, the tree or branch can sometimes be saved by surgical removal of the canker. Using a chisel and a sharp knife, excise all discolored bark and wood from the wound. All tools should be sterilized with rubbing alcohol after each cut to prevent spreading the disease organisms to healthy tissue. To hasten the healing process and promote vigorous growth, fertilize and water the tree regularly. For more information about fertilizing and watering, see the index.
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Bark Wounds
Cankers
