Thousand Cankers Disease in Ohio
HIGHDisease
Thousand Cankers Disease is currently active in Ohio. Watch your susceptible trees closely and act early.
About Thousand Cankers Disease
A disease complex involving the walnut twig beetle and an associated fungus that has caused significant mortality of black walnut, particularly in western states. Thousands of small cankers coalesce to girdle branches and the trunk.
Symptoms to watch for
Yellowing and thinning of upper canopy, branch dieback progressing downward, tiny bark beetle entrance holes, numerous small dark cankers under bark that merge together, staining of sapwood
Trees at risk in Ohio
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Treatment options
Quarantine and Firewood Restrictions
State quarantines restricting movement of walnut wood products and firewood from infested areas. The primary regulatory tool to slow disease spread to new regions.
Maintain Tree Health
Proper watering, mulching, and fertilization to maintain vigor of walnut trees, as stressed trees are more susceptible. Avoid wounding bark. No chemical treatments have proven effective.
Recommended Products & Tools
Helpful supplies for managing Thousand Cankers Disease. Always read and follow label directions, and confirm a diagnosis before treating.
Protectant spray for many bacterial and fungal diseases.
For the rare case sealing is advised (e.g., oaks in oak-wilt season).
Sharp, clean cuts to remove affected wood — a tree-care essential.
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Need help with Thousand Cankers Disease in Ohio?
Connect with ISA Certified Arborists serving Ohio:
Browse all Ohio arborists →Frequently asked questions
Is Thousand Cankers Disease in Ohio?
Thousand Cankers Disease is currently active in Ohio. Watch your susceptible trees closely and act early.
What does Thousand Cankers Disease look like?
Yellowing and thinning of upper canopy, branch dieback progressing downward, tiny bark beetle entrance holes, numerous small dark cankers under bark that merge together, staining of sapwood
What trees does Thousand Cankers Disease affect in Ohio?
It affects Black Walnut. Susceptibility varies by species.
How do I treat Thousand Cankers Disease?
Options include: Quarantine and Firewood Restrictions, Maintain Tree Health. Confirm the diagnosis before treating, and consider a certified arborist for high-value trees.