Dutch Elm Disease
CRITICALOphiostoma ulmi / O. novo-ulmi
Overview
A devastating vascular wilt disease spread by elm bark beetles that has killed millions of American elms since the 1930s. The fungus blocks water-conducting vessels, causing rapid wilting. It fundamentally changed the American urban landscape.
- Type
- Disease
- Severity
- CRITICAL
- Source
- USFS
Symptoms
Wilting and yellowing of leaves on individual branches (flagging), brown streaking in sapwood visible when bark is peeled, rapid progression of wilt through the canopy, premature leaf drop
Affected Species
Geographic Spread
Treatments
Fungicide Trunk Injection (Thiabendazole)
Preventive injection of thiabendazole-based fungicide (Arbotect) into the root flares of high-value elms. Provides 2-3 years of protection. Must be applied before infection occurs.
Sanitation Pruning and Removal
Rapid removal of infected branches or entire trees to eliminate beetle breeding habitat and reduce local inoculum. Root graft disruption between adjacent elms prevents underground spread.
Resistant Elm Cultivar Planting
Replacing lost elms with DED-resistant cultivars such as 'Princeton', 'Valley Forge', or 'Jefferson'. These selections maintain the classic elm form with strong disease resistance.
Recommended Products & Tools
Helpful supplies for managing Dutch Elm 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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Frequently Asked Questions
What is Dutch Elm Disease?
A devastating vascular wilt disease spread by elm bark beetles that has killed millions of American elms since the 1930s. The fungus blocks water-conducting vessels, causing rapid wilting. It fundamentally changed the American urban landscape.
What are the symptoms of Dutch Elm Disease?
Wilting and yellowing of leaves on individual branches (flagging), brown streaking in sapwood visible when bark is peeled, rapid progression of wilt through the canopy, premature leaf drop
Where is Dutch Elm Disease currently found?
Dutch Elm Disease is currently active in Alabama, Arkansas, California, Colorado, Connecticut, District of Columbia, Delaware, Georgia, Iowa, Idaho, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Vermont, Washington, Wisconsin, West Virginia, Wyoming. It has been reported in 45 total states across the United States.
What plants are affected by Dutch Elm Disease?
Dutch Elm Disease affects American Elm. Susceptibility varies by species.
How do I treat Dutch Elm Disease?
Treatment options for Dutch Elm Disease include: Fungicide Trunk Injection (Thiabendazole), Sanitation Pruning and Removal, Resistant Elm Cultivar Planting. Treatment approaches may include chemical, biological, cultural, and mechanical methods depending on the severity and context.
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