WSU Extension


Ornamental Plum
Armillaria root rot 
Brown rot 
Crown gall 
Cytospora canker 
Plum pockets 
Shothole (Coryneum blight) 
Silver leaf 
Hop aphid 
Leaf curl plum aphid 
Peachtree borer 
Pear slug 

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Caption: Cytospora-infected peach twigs
Photo by: R.S. Byther
Ornamental Plum : Cytospora canker
(revision date: 4/28/2014)

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

Non-Chemical Management
  • 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.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Cytospora-infected peach twigs
Photo by: R.S. Byther