Beech leaf disease is thought to be associated with the nematode Litylenchus crenatae, a microscopic worm that enters and spends the winter in leaf buds, causing damage to leaf tissue on American, European, and Asian beech speciesm, explains the Michigan Department of Agriculture and Rural Development (MDARD). From one year to the next, leaf curling and distortion may progress, resulting in withered or yellow leaves and a thin canopy. Noticeable leaf loss can occur in early summer on heavily infested trees. Trees weakened by leaf damage become susceptible to other diseases and can die within six to 10 years after initial symptoms.
Many questions about beech leaf disease remain unanswered. Researchers are still working to understand if the Litylenchus crenatae nematode is the primary cause of the disease or the carrier of another causal agent responsible for the disease.
Currently, there are no known treatments to protect trees or reduce disease impacts, although trials are ongoing.
Confirmed populations in Michigan
Beech leaf disease was first confirmed in Michigan in July 2022 after landowners noticed its characteristic thickened leaf bands on trees in a small woodlot in St. Clair County. Since then, new detections in Oakland and Wayne counties indicate the disease is more widespread.
Since January of 2021, beech leaf disease has been listed on Michigan's invasive species watch list to encourage nurseries, foresters, residents, and land managers to look for and report suspected infestations.
Reporting potential infestations
Look for signs of beech leaf disease on American or ornamental beech trees. If you suspect you have found a symptomatic tree, take photos of the infested tree, including close-ups of affected leaves; note the date and location, and report it in one of the following ways:
For more information, visit Michigan.gov/Invasives/ID-Report/Disease/Beech-Leaf-Disease.
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