Mountain Ash: Nectria canker

categories: Mountain Ash Mountain Ash Diseases Ornamental trees Ornamentals

revision date: 2022-11-25 11:47

Coral or reddish Nectria canker fruiting bodies.
Nectria canker fruiting bodies
Photo by: R.S. Byther


Nectria canker is a fungal disease often found on twigs and branches that have been weakened by drought, frost damage, insect damage, or other diseases. Cankers are initially distinguished by discolored bark with coral or reddish fungal fruiting bodies. The cankers are sunken and often associated with wounds. Older cankers develop concentric, target-like rings of wood. Affected branches may have stunted or wilted leaves, or fail to produce leaves in the spring. Branches may be girdled.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

  • Provide proper plant care. Healthy plants are more resistant to disease.
  • Plant trees or shrubs that are adapted to your climate. Minimizing frost damage and water stress increases disease resistance.
  • Avoid wounding trees. Do not prune in late summer or fall.
  • Prune and destroy infected branches. Make cuts well below diseased tissues.
  • Do not leave stubs when pruning.

Chemical Management

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

  • None recommended