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Beech Leaf Disease

a single beech leaf with striping and brown patches
beech tree leaves with dark striping, a symptom of beech leaf disease
Beech leaves exhibiting the striping
associated with beech leaf disease

Beech leaf disease (BLD) affects and kills both native and ornamental beech tree species. It is associated with a nematode, Litylenchus crenatae mccannii. This disease has only been discovered in recent years and much about it, including the full cause and how it spreads, is still unknown. Because of this, DEC is collecting information on symptomatic beech across New York State in the hopes of learning more about the disease.

On this page:

Threat to Beech

Beech leaf disease can kill mature beech trees in 6-10 years and can kill younger trees even more quickly. Some cases have shown saplings being killed in as little as one year.

In New York State where our predominant forest type is beech/birch/maple, beech is one of the most common forest species. Beech is particularly valued in the forest for hosting nesting sites and providing nuts for birds, black bears, and other wildlife.

Disease Symptoms

Symptoms of this disease are seen in the leaves and include striping, curling, and/or leathery texture. These symptoms may be visible from leaf out in May until leaves fall off in October and are most easily noticed by looking up into the forest canopy. Eventually, affected leaves wither, dry, and yellow.

Reduced leaf and bud production may also occur. Leaf loss has been recorded only in heavily affected trees, but would be noticeable in summer months. A single tree can contain both heavily infected and unaffected branches.

Known Locations in New York and Neighboring States

map of northeastern US showing areas with beech leaf disease
BLD is currently known to be present in both western and southeastern NY counties.

Beech leaf disease has been found in Chautauqua, Cattaraugus, Erie, Rockland, Westchester, and Suffolk counties in New York. We suspect there are infestations elsewhere that we have not yet found, and tracking locations of this disease will help us learn more about its biology.

The disease was first discovered in Ohio in 2012. Neighboring infections currently exist in Ohio, Pennsylvania, Connecticut, and Ontario, Canada.

Current Control Efforts in New York State

DEC's Forest Health team is surveying trees across the state to:

  • identify infested stands,
  • monitor the disease severity and progression, and
  • research possible methods of spread by trapping and analyzing insects from both affected and unaffected stands.

DEC has partnered with other affected states to conduct research and share findings on beech leaf disease.

Currently, there is no known way to control or manage this disease.

How to Report

a canopy of beech leaves with the striping associated with beech leaf disease
The backlighting seen when looking up into the forest canopy can
help you spot the leaf striping associated with beech leaf disease.

Because so much about this disease is unknown, finding new infestations can help us learn more about how BLD spreads. Determining and understanding this information is the first step towards developing management techniques. As of summer 2020, beech leaf disease is present on either side of the state, but there could be other locations out there that we have not yet found.

After reviewing the identification materials on this website, if you think you have seen signs of beech leaf disease:

  1. Take photos of symptoms, as well as the tree's leaves, bark, and the entire tree if possible. Photos of leaves held up to the light, or taken through the canopy, make it easier to identify BLD symptoms.
  2. Email photos and location information to DEC at foresthealth@dec.ny.gov. Or you may call us via phone at 1-866-640-0652.
    1. If you have an iMapInvasives account, you may report through iMap instead (leaves DEC website) and cite the beech leaf disease nematode (Litylenchus crenatae mccannii).

What You Can Do to Help Stop its Spread

Please follow the New York State Firewood Regulation to help prevent the spread of all pests and diseases that threated our forests. Do not move untreated firewood more than 50 miles from its source or origin. If BLD symptoms are observed in an area, avoid moving firewood from that location.

Lookalikes and Other Beech Phenomena

Review the table below for other issues you may see on beech trees. It is possible for a beech tree to exhibit symptoms of both beech leaf disease and any of these other impacts simultaneously.

DEC is interested in reports of leaf striping or curling associated with BLD on any beech tree, but we do not manage the other issues listed in the table.

If you have questions about any of the diseases or phenomena listed in the table, please click "learn more" in the "About" column.

Name Signs and Symptoms About
Beech bark disease (BBD)

Symptoms: The symptoms of this disease are concentrated on the bark. A white, fuzzy coating on the tree's trunk and branches is a sign of the scale insect.

Bark of a tree affected by beech bark disease. Bark has open wounds and is warped in shape.
Photo by Linda Haugen, USDA FS, Bugwood.org

Beech bark disease is the result of the combined effects of a non-native scale insect and a canker fungi. The insect pierces and sucks at the tree, allowing the fungus to enter and cause harm internally. This disease is common across New York State and is not managed by DEC.

Most trees die within 10 years of infestation by the insect and fungi.

Learn more (leaves DEC website).

Erineum patch

Symptoms: Yellowish patches appear on the upper side of the leaf. The patches are light green in spring, then fade to orange and eventually brown.

green beech leaves with dead patches between veins
Photo by Eric R. Day, Virginia Polytechnic and State University, Bugwood.org

Erineum patch is caused by eriophyid mites and is not typically viewed as a problem. The patches rarely cover enough of the leaf to affect the overall health of the tree.

Learn more (leaves DEC website).

Powdery mildew

Symptoms: Leaves and stems appear to be covered in a white, powdery substance that resembles powdered sugar.

powdery, white fungi on leaves
Photo by University of Georgia Plant Pathology, Bugwood.org

Powdery mildew is caused by native fungi and affects a variety of shrubs and trees. This is a cosmetic disease that does not kill the tree but could cause defoliation if not addressed.

Learn more (leaves DEC website).

Anthracnose

Symptoms: Small brown or black spots on leaves that eventually cause dead areas. New leaves may curl.

green beech leaves with some brown patching between veins
Photo by Nancy Gregory, University of Delaware, Bugwood.org

Anthracnose affects a variety of tree species and is caused by a group of fungi. In beech, the fungi infect the leaves and stems and can cause dieback or some defoliation. The disease thrives in years where there are cool, wet conditions during bud break.

Learn more (leaves DEC website).

Beech blight aphid

Signs: These native insects have a fluffy, white outer coating. Also known as "boogie woogie aphids", the insects will shake or "dance" when the branch is disturbed in order to ward off potential predators.

fuzzy, white beech blight aphids on a branch
Photo by Steven Katovich, Bugwood.org

This insect is native and feeds on beech without causing much harm.

Learn more (leaves DEC website).

Marcescense

Signs: Beech retain their dead leaves through the winter.

brown beech leaves in winter

This is a totally normal, common, and harmless feature of beech.

Learn more (leaves DEC website).

Additional Resources