darker green stripes on beech leaves

Beech leaf disease symptom. Photo: Jim Chatfield, OSU Extension

Updated: October 31, 2023

Key points about Beech Leaf Disease

  • Beech leaf disease (BLD) causes significant dieback, decline, and death of beech trees. BLD was first detected in the Cleveland, Ohio area in 2012. Since then, it has been detected in other Ohio counties, Connecticut, Massachusetts, New Jersey, New York, Pennsylvania, Rhode Island, West Virginia, Virginia, and the Canadian Province of Ontario. The Maryland Department of Agriculture confirmed the presence of beech leaf disease in Maryland in September 2023. It is now in at least 8 Maryland counties:  Alleghany, Anne Arundel, Baltimore, Cecil, Charles, Frederick, Harford, and Washington.
  • The disease is caused by an invasive foliar-feeding nematode (a microscopic worm), Litylenchus crenatae subsp. mccannii. The nematode overwinters in leaf buds and enters leaves as they develop in the spring. Scientists are trying to find out how the nematodes spread and how they can be managed to protect tree health.
  • All beech species, including native American beech (Fagus grandifolia), European beech (Fagus sylvatica), and Oriental beech (Fagus orientalis) are susceptible to the disease. American beech, native to eastern North America, is a beautiful and important forest tree known for its smooth bark. Beeches are also planted as ornamental trees in the landscape. 
a map showing the distribution of beech leaf disease in the northeast United States as of February 2023
Initial observations of Beech Leaf Disease, as of February 2023. Source: Cleveland Metroparks
the smooth grey bark of a beech tree
The smooth, iconic, grey bark of a mature American beech tree. Photo: C. Carignan, UME

Symptoms of Beech Leaf Disease

  • Dark stripes or bands between the veins of leaves are a distinct, early symptom of BLD infection. They are visible immediately upon bud break in the spring. 
  • The bands are best seen by looking at the leaves from below and allowing sunlight to pass through the leaf tissue.
  • Thickening and leaf distortion can also be observed.
  • Infected leaves may be unevenly distributed in the lower canopy of a tree.
  • Thinning of the leaf canopy happens over time due to early leaf drop and aborted leaf bud development. This stresses and weakens trees, causing them to die.

Dark bands on the leaves of American beech, a symptom of Beech Leaf Disease. Photo: Matthew Borden, Bartlett Tree Experts, Bugwood.org

Damage to American beech, caused by Beech Leaf Disease. Photo: Matthew Borden, Bartlett Tree Experts, Bugwood.org

Damage to European beech, caused by Beech Leaf Disease. Photo: Matthew Borden, Bartlett Tree Experts, Bugwood.org

What to do if you find Beech Leaf Disease

  • Report beech leaf disease symptoms to the Maryland Department of Agriculture by email, fpm.mda@maryland.gov
  • If you are uncertain as to whether the symptoms you are seeing are beech leaf disease, you can first send digital photos to us at Ask Extension and we can assist with preliminary identification.

Resources and additional resources

(PDF) Beech Leaf Disease Pest Alert | USDA Forest Service

Beech Leaf Disease Confirmed in Virginia | Virginia Department of Forestry

New Leaf Disease is a Beech | The Maryland Invasive Species Council 

Compiled by Debra Ricigliano (retired), HGIC. Reviewed by Dr. Dave Clement, Extension Specialist, Plant Pathology. Revised by Christa Carignan, Horticulturist, HGIC. (9/23)