What beech leaf disease is
Beech leaf disease is caused by a microscopic worm-like nematode that feeds inside the buds of beech trees. Infected leaves come out damaged, the tree loses its ability to make food, and over several years branches die back and the tree can die. It affects American beech as well as European and other ornamental beeches.
Where it's been found
The disease was first identified in Ohio in 2012 and confirmed in Michigan in 2022. Since then it has been found in several southeast Michigan counties, and it continues to spread. Not every area has it yet, so suspected cases are worth reporting. The Michigan DNR and MSU Extension track new finds.
Signs to look for
- Dark green bands between the leaf veins, easiest to see looking up at leaves from underneath, against the sky.
- Leaves that are thick, leathery, crinkled or curled.
- Thinning canopy and fewer buds over time.
- Small, aborted or yellowing leaves in later stages.
Not to be confused with beech bark disease
Beech bark disease is a different, older problem in Michigan, caused by a scale insect and a fungus that attack the bark. It shows up as white, woolly patches on the trunk, cankers, and eventually trunks that snap partway up ("beech snap"). A tree can have one, both or neither.
What you can do
- Report it if you think you've found it in an area where it hasn't been confirmed. The Michigan DNR takes reports and photos.
- Don't move beech material such as nursery trees, branches or leaves from affected areas.
- Ask about treatment for valuable trees. Some treatments are being studied and used on high-value beeches; an ISA Certified Arborist can tell you what's currently recommended.
- Plan ahead for declining beeches near the house. A beech that's dying back, especially one also hit by beech bark disease, can drop limbs or snap.
Not sure what's wrong with a beech? See tree health & risk checks or request an estimate with photos of the leaves and trunk.
Common questions
What does beech leaf disease look like?
Dark green stripes between the veins of beech leaves, best seen from underneath against the light, plus thick, crinkled leaves. Over several years the canopy thins and branches die back.
Is beech leaf disease in northern or west Michigan?
Confirmed finds have been concentrated in southeast Michigan, but the disease is spreading. If you see the symptoms elsewhere, report it to the Michigan DNR.
Can beech leaf disease be treated?
Treatments for high-value trees are being studied and used in some places. Ask an ISA Certified Arborist what's currently recommended for your tree.
Should I remove a beech tree with beech leaf disease?
Not necessarily right away. Trees decline over several years. If the tree is near a house or driveway and is dying back or also has beech bark disease, plan to have it assessed and possibly removed.