WSU Extension


Bacterial canker 
Brown rot 
Cytospora canker 
Shothole (Coryneum blight) 
Silver leaf 
Brown marmorated stink bug 
Peach twig borer 
Peachtree borer 

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Caption: Cytospora-infected peach twigs
Photo by: R.S. Byther
Apricot : Cytospora canker
(revision date: 5/20/2014)

The fungi which cause Cytospora canker attack through wounds on twigs and branches. Initial cankers are small, but enlarge quickly and may streak up and down the stems without girdling. The cankers may also girdle twigs, resulting in dieback above the infection site and causing "flags" of dead material to appear in the canopy. The leaves on the dead twigs turn color and droop, but often remain attached. The canker itself appears as a dark, sunken area of dead bark and wood. Later, callus forms at the margin of the canker. Amber gumming is often present. Pinhead-sized black fruiting structures of the fungi often erupt through the bark and produce orange tendrils or droplets of spores in wet weather. Spores are easily spread by wind, rain, and insects. The cankers may enlarge over several seasons.
Management Options

Non-Chemical Management
  • Provide proper planting sites and culture. Healthy trees are more resistant to disease and winter injury.
  • Avoid wounding trees.
  • Avoid overhead watering.
  • Control insect and disease problems to minimize injuries.
  • Prune out and destroy infected tissues during dry weather. Make cuts at least 12" below visibly infected area.
  • Rake and destroy infected twig debris.
  • Correct pruning practices minimize injury and improve wound healing. For information see PNW 400, Training and Pruning Your Home Orchard, or contact WSU Master Gardeners or your county Extension agent.
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