The introduction of Dutch elm disease in the 1930s marked a turning point in American urban forestry. Millions of the once iconic elm trees across the U.S. were lost. The disease originated in Asia, where native elm species show some natural resistance, but it was first identified outside the region in the Netherlands, giving rise to its name. Unfortunately, most elm varieties outside Asia lacked immunity, making them highly vulnerable.
What Is Dutch Elm Disease?
Dutch elm disease is caused by one of two fungal pathogens (Ophiostoma ulmi and Ophiostoma novo-ulmi) and is spread primarily by elm bark beetles.
- Beetles lay eggs beneath the bark
- As larvae develop, they tunnel through the sapwood and inner bark
- Adult beetles emerge carrying fungal spores, which are transmitted to healthy trees when the beetles feed
Once infected, the fungus disrupts water movement within the tree, causing rapid wilt and often death.
Thankfully, Dutch elm disease never reached Florida’s native elms, preserving five species:
- Florida Elm (Ulmus americana var. floridana)
- Winged Elm (Ulmus alata)
- Cedar Elm (Ulmus crassifolia)
- Slippery Elm (Ulmus rubra)
- American Elm (Ulmus americana)
Because of this natural buffer, Florida played a role in developing disease-resistant elm cultivars, which have been reintroduced to northern urban landscapes since the 1990s. These cultivars are helping restore the canopy of parks and city streets where elms were once dominant.
You will also find Chinese Elm (Ulmus parvifolia) in urban settings dues to its disease resistance.
Managing Dutch Elm Disease Today
If you live in a region where Dutch elm disease remains a concern, consider two proactive strategies:
- Plant disease-resistant cultivars – many are available through nurseries specializing in urban forestry
- Fungicide injections – consult an ISA Certified Arborist trained in tree injection for protection of high-value specimens (treesaregood.org)
Lessons From This Disease
One of the most important messages we can take from the spread of Dutch Elms Disease, and other similar best and diseases, is the need to maintain diversity in our urban landscapes. One reason Dutch Elms Disease was able to spread so widely, and so fast, was due to the simple fact that there were so many elms in out urban landscapes. With the limited plant palate often used in urban settings, we may see another species sufferer a similar fate as our northern elms.
Whether you are an urban planner, or a homeowner, work to create landscapes diverse in all plant species. Contact your local extension office to assistance with species selection for your area, or use the FFL Plant Guide.
Additional Resources:
Dutch-Elm-disease-UM Extension
This article was edited with Co-Pilot
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