Beech Leaf Disease: Mistaken Identity

By Hannah Harkness, NCRN I&M Science Communications Intern

Beech leaf disease.

NPS/Brolis

An Emerging Threat

Beech leaf disease (BLD) is an emerging threat to beech trees (Fagus sp.) in the National Capital Region (NCR) and beyond. Since beech is the most common tree species found in the NCR (as of 2023) it is helpful to learn how to identify BLD and avoid falling for look-alikes!

First, Make Sure it's a Beech

Characteristic features of a beech tree. Leaves are oval, serrated, and have an alternate pattern (top) and bark is smooth and gray (bottom).

NPS/Vinduska (top) NPS/Sheline (bottom)

Distinctive features of beech trees include:

• Oval-shaped leaves with serrated edges
• Yellow or bronze leaves that stay on the tree through the fall and winter
• Smooth, gray bark
• Leaf veins arranged in an alternating pattern

Learn more about identifying beech trees: How to Identify the American Beech

Beech trees showing distinctive yellow and bronze leaves in winter.

NPS/John Zuke

Beech Leaf Disease: Signs and Symptoms

Beech Leaf Disease (BLD) causes very distinctive symptoms. Evidence of BLD on beech trees can be found in the canopy; diseased leaves will show characteristic dark banding between the veins of the leaf. Leaves also tend to be wrinkled and misshapen, which worsens as the disease progresses.

Characteristic symptoms of beech leaf disease on beech leaves.

NPS/Brolis

Other Pests Affecting Beech

Beech trees can suffer from various afflictions that can be confused for BLD. It is important to make a distinction between different pests and pathogens to assess the health of beech trees.

Woolly Aphid

Woolly aphids (Eriosoma lanigerum) are a common forest pest that changes beech leaf appearance. These small insects cause beech leaves to develop pale or yellow banding between veins of the leaf. They can also leave behind pale spotted patterns along these leaves.

Woolly aphid damage on beech leaves.

NPS/Brolis

Beech Erineum Mite

Another beech pest is the beech erineum mite (Acalitus fagerinea). These microscopic mites cause a dark spotting pattern of galls, or small growth deformities on the leaf. This pattern can appear similar to BLD, but the discoloration creates less organized bands on the leaf. These spots can also be raised or lighter in color depending on the severity of infection.

Beech erineum mite damage on beech leaves.

Charles Smith (Strick Tree Services)

Leaf Curling Aphid

A more generalized pest that sometimes attacks beech is the leaf curling aphid. This term refers broadly to several types of aphids, which attack beech as well as other tree species. These aphids cause leaves to curl along their edges and can cause yellowing between veins of the leaf that can be mistaken for BLD. Sometime aphids will leave behind cast skins on the underside of leaves that appear as brown bumps.

Leaf curling aphid damage on a beech leaf.

NPS/Brolis

What to do when you spot BLD (and other pests)!

• Report any pest sightings to local county authorities or department of agriculture. For good measure, you can also report them on iNaturalist. 
• Consult with local forestry experts and ISA Certified Arborists for advice and assistance on tree-related issues. 

Further Reading

• Carta, L.K., Handoo, Z.A., Li, S., Kantor, M., Bauchan, G., McCann, D., Gabriel, C.K., Yu, Q., Reed, S., Koch, J., Martin, D., and Burke, D.J. 2019. Beech leaf disease symptoms caused by newly recognized nematode subspecies Litylenchus crenatae mccannii (Anguinata) described from Fagus grandifolia in North America. Forest Pathology.
• Chatfield, Jim and Boggs, Joe. 2018. Ohio State University Extension. Diagnostics of Beech Leaf Disease: The Ultimate Beech Read
• National Park Service. 2022. Beech Trees in the National Capital Area
• US Forest Service. 2022. Pest Alert: Beech Leaf Disease
• Washinton University Arboretum. 2024. Washington University in St. Louis. How to Identify the American Beech