Ornamental Plum: Cytospora canker

Biology

Cytospora canker infects the bark and cambium (the growing layer beneath the bark), and may be found in the outer layers of wood. Cuts into newly infected areas often reveal a reddish discoloration in the inner bark. Leaves above the infection site droop and discolor and twigs die back, resulting in “flags” of dead material. Infected branches develop cankers which may display gumming (oozing sap), a dead twig at the center of the canker, pinhead-sized bumps on the bark, and a sunken area on the surface of the branch at the canker margin. Amber to orange-colored spores may be seen oozing from the pinhead-sized bumps. The canker may girdle and kill the branch or increase in length each year, resulting in a “perennial canker”. This fungal disease often infects through injury sites.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Avoid wounding trees.
• Avoid overhead watering, which can spread infection.
• Control insect and disease problems to decrease chances of wounding.
• Prevent winter injury by not fertilizing late in the growing season and protecting the trunk from strong sunlight in freezing weather.
• Prune out and destroy infected twigs and branches during the summer, cutting 12″-15″ below infected area. Remove cankers on trunks and large branches. Disinfect pruning tools after use.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended