What's The Issue?

The forests of the Northeastern United States and Canada are facing a silent but serious threat—Beech Leaf Disease (BLD). First spotted in Ohio in 2012, this fast-spreading disease is now making its way through New York, recently surfacing in 15 new counties, including Oswego. And it’s not just native beech trees at risk—ornamental varieties are also vulnerable.

BLD is believed to be linked to a microscopic nematode called Litylenchus crenatae mccannii. But the story might be more complex. Scientists aren’t yet sure whether this nematode is the sole culprit or if it’s working in tandem with another pathogen—possibly a bacterium, fungus, or virus. Research is ongoing, and while treatments are being explored, there’s currently no known cure.

American beech trees are more than just beautiful—they’re foundational to the northern hardwood forest ecosystem, which includes maple, birch, and beech. These forests cover over half of New York’s wooded landscape. Wildlife such as bears, deer, and birds depend on beech nuts (mast) for energy, especially during colder months. If BLD continues to spread unchecked, the ripple effects could reshape entire ecosystems.

What Can Be Done?

You don’t need to be a scientist to help. Here’s how you can get involved:

  • Learn to recognize BLD symptoms: Look for dark bands between leaf veins, leaf curling, and premature leaf drop.

  • Report your findings: Use NYiMapInvasives’s free mobile app to report sightings and help track the disease’s spread.

  • Get outside: Take a hike, explore your local woods, and inspect beech trees. Your observations could make a real difference.

  • Review the information below to learn more! 

Beech Leaf Disease is a reminder of how interconnected our forests are—and how even the smallest organisms can have big impacts. By staying informed and involved, we can help protect these vital trees for generations to come.

Join a Training

Looking for a more hands-on approach? Enjoy a guided walk in the woods, and learn to recognize and report Beech Leaf Disease.

  • When: Friday, September 26th, 10 AM- 12 PM
  • Where: Salmon River Falls UMA, Richland, NY. 
Get Details & Register

What to Look For

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).

  • Striping 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.
Beech Leaf Disease Flyer

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

Where to Look?

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.  

Identifying Beech Trees

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

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