Beech leaf disease (BLD) is a tree disease that causes leaf deformities and leads to mortality in native and ornamental beech tree species. BLD is believed to be caused by the nematode Litylenchus crenatae mccannii (pictured).  It is unknown whether the nematode causes all of the damage, or if it is associated with another pathogen such as a bacteria, fungus, or virus. Research on possible treatments is ongoing. 

Photo by Paulo Vieira, USDA, ARS


American beech trees are an important component of the northern hardwood forest type (maple-beech-birch) which makes up more than half of the forested land in New York. Many wildlife species rely on beech mast as a main source of energy. The loss of beech trees would cause changes in forest structure that would affect the whole ecosystem.


BLD symptoms appear in the leaves and include striping, curling, or a leathery texture. These signs may be visible year-round, as some beech trees may hold their leaves in winter. Stripes are most noticeable on the underside of leaves and you may see them by looking up into the canopy or holding branches up to the light. Eventually, affected leaves wither, dry, and yellow (NYSDEC).

  • Stripping on leaves is most visible from the underside. 
  • Hold leaves up to the light to look for dark strips along the veins. 
  • Some infested trees only have a few leaves that show symptoms so search carefully throughout the canopy. 

Since so much about beech leaf disease is unknown, learning of new infestations aids research and management efforts. Reports in counties where BLD has been newly found and in counties where it has not been found are especially needed.

If you think you have found beech leaf disease follow these steps: 

  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. Submit a report through iMapInvasives  Beech leaf disease is listed as the nematode Litylenchus crenatae maccannii.

Identifying Beech Trees

  • Beech tree bark is gray in color & usually smooth in texture (left photo).

Beech trees may show signs of beech bark scale and beech bark disease. 

  • The bark of a beech tree infested with beech scale may have scattered woolly spots on the tree trunk (middle photo).
  • Beech scale may lead to an infestation of different fungi that combined with the presence of the scale result in beech bark disease which causes the bark to have bumps and cankers (right photo). 
  • Beech leaves are ovate; every leaf vein ends in a tooth, and leaves are not hairy (right leaf pictured above). 
  • Eastern hophornbeam has a similar leaf but there are teeth along the edge that are not at the end of a leaf vein (left leaf pictured above).

Management:  There is still much unknown about how beech leaf disease infects and spreads. Below are a few methods that could be effective for managing or preventing BLD. 

Prevention is the best management option. If BLD is present in an area, avoid moving soil, and beech tree material including firewood, branches, twigs, leaves, and seedlings from the infected location. In addition, follow all NYS firewood regulations and don’t move firewood more than 50 miles from its original source.

Disinfect footwear with a  solution of bleach and water immediately after walking through stands of trees with BLD. 

Chemical:  Preliminary findings through the Maine Forest Service show that soil applications of Phosphite products have been effective for managing beech leaf disease. Nematicides may also be an effective chemical control method although application timing is still being researched (University of Massachusetts Amherst). 

Get Involved

There is a state-wide effort to track the spread of beech leaf disease. You can help by learning to recognize symptoms of the disease and report observations to iMapInvasives.org, New York’s invasive species observation database. 

You can choose any public location to search for signs of beech leaf disease. The map below shows suggested survey sites and confirmed observation sites for beech leaf disease. Data from iMapinvasives.org was used to generate confirmed observation locations. Suggested survey sites were selected based on proximity to confirmation sites and public accessibility.  

Aid Early Detection Efforts

 Searching for invasive species populations in an effort to detect their presence before their populations become too large to manage is vital to reducing the impacts of invasive species on our natural ecosystems.

Click the link below to learn more about the species we’re enhancing early detection efforts for and to join our invasive species Volunteer Surveillance Network to aid this effort (training will be provided). 

Report Invasive Species

NYiMapInvasives is an online, collaborative, GIS-based database and mapping tool that serves as the official invasive species database for New York State.

 Click the links below to become familiar with iMap


Prevent the introduction of invasive species into the SLELO PRISM.

Rapidly detect new and recent invaders and eliminate all individuals within a specific area.

Share resources, including funding personnel, equipment, information, and expertise.

Collect, utilize, and share information regarding surveys, infestations, control methods, monitoring, and research.

Control invasive species infestations by using best management practices, methods and techniques to include: ERADICATION (which is to eliminate all individuals and the seed bank from an area), CONTAINMENT (which is reducing the spread of established infestations from entering an uninfested area) and SUPPRESSION which is to reduce the density but not necessarily the total infested area.

Develop and implement effective restoration methods for areas that have been degraded by invasive species and where suppression or control has taken place.

Increase public awareness and understanding of invasive species.

Develop and implement innovative technologies that help us to better understand, visualize, alleviate or manage invasive species and their impacts or that serve to strengthen ecosystem function and/or processes.

Take the Pledge, Get the Tools & Earn the Badge!

Protect your favorite outdoor spaces from invasive species. 

Rob Williams                              rwilliams@tnc.org                     Program Director

Megan Pistolese megan.pistolese@tnc.org
Outreach and Education

Brittney Rogers brittney.rogers@tnc.org 
Aquatic Invasive Species

Robert Smith       robert.l.smith@tnc.org 
Terrestrial Invasive Species

Zachary Simek    zachary.simek@TNC.ORG     Conservation and GIS Analyst

During this time the best way to contact our team is via email.