WSU Extension


Common Diseases : Tubercularia canker
(revision date: 4/30/2013)

Tubercularia canker is a fungal disease typically affecting twigs and branches, and occasionally trunks, of several species including elm, Russian olive, and Japanese maple. This disease is easily diagnosed by observing the creamy orange spore stage of the fungus, which appears in the cankered areas as small spots. The characteristic coloration and appearance of the fungus has led to the disease sometimes being referred to as "coral spot". Tubercularia is a weak pathogen most often associated with wounds, winter-injured stems, or other disease problems. In Japanese maple it may also be associated with a Verticillium infection.
Management Options

Non-Chemical Management
  • Avoid leaving pruning stubs. Make a sharp, clean cut which will heal promptly.
  • Avoid wounds.
  • Maintain tree vigor through proper fertilizing and watering. Avoid fertilization in late summer and fall which delays dormancy and predisposes trees to winter injury.
  • Prune during dry weather near the end of the dormant period. Make cuts well below infected area and disinfect pruning tools between cuts to avoid spreading infection.
  • Remove and destroy affected twigs and limbs. Do not leave them on the ground between the rows, but carry them out to a burn pile or rotovate them into the soil so they are completely buried.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

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Caption: Tubercularia canker fruiting bodies
Photo by: R.S. Byther
Caption: Tubercularia canker fruiting bodies
Photo by: R.S. Byther