Common Diseases: Cankers

categories: Common Diseases Common Problems

revision date: 2022-11-04 02:56

Black canker and peeling bark on madrone.
Black canker and peeling bark on madrone
Photo by: R.S. Byther

Biology

Cankers are localized wounds or necrotic lesions, often sunken beneath the surface of the stem of a woody plant. Cankers can be caused by fungi, bacteria, or winter damage. Determining the cause of the problem is the first step in managing a canker problem. Examine the canker for fruiting bodies of fungal pathogens. Check diagnostic references for the common canker problems on that particular host plant.

Management Options

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

Non-chemical Management

Select non-chemical management options as your first choice!

  • Plant trees properly and in suitable locations. Protect from rain and frost, if feasible.
  • Burn or cauterize cankers using a hand held propane burner to kill pathogens and lessen disease spread.
  • Give the plants appropriate care. This keeps trees vigorous and helps them to better resist disease.
  • Remove and destroy cankered branches when first noticed. Perform disease management pruning or surgery during dry weather, and especially before fall rains. Sterilize pruning tools between cuts and before use on healthy plant tissues to avoid spreading disease.

Chemical Management

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

Determine the cause of the problem. Then refer to the fact sheet for management options specific to that host plant and causal organism.

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