A new pathogen has been detected in the Adirondacks. Beech Leaf Disease has the potential to spread rapidly. The Adirondack Park Invasive Plant Program held a seminar recently bringing together plant and forest scientists to discuss what is known about the pathogen and promote a citizen science project to identify and track it.
Beech Leaf Disease was first detected in North America in Ohio in 2012 and although it has been spreading scientists do not know a lot about it.
New York State Department of Environmental Conservation Forest Health Specialist Maria Moskalee says Beech Leaf Disease is the latest threat to the American Beech tree. It can kill mature trees in 6 to 10 years and younger trees within a few years. It raised alarm this year when it was found in Herkimer County, the first of 30 counties in the state with the disease in the Adirondacks.
“In New York DEC Forest Health first started hearing reports of striping on leaves and thinning beech canopies in 2017. We first started tracking it as Beech Leaf Disease in 2018. At that time the only detections were in the most southwestern part of the state. Each year since we’ve seen a significant expansion of the disease range. So far this year we have found Beech Leaf Disease in 15 new counties.”
The biology and vectors of the disease are not well understood. Researchers have found that a nematode causes symptoms of the disease, but they are not sure if it is the only cause or if other pathogens are factors. Moskalee said they also don’t know how the disease spreads.
“Birds or human spread are two theories. The first time BLD is found in a new county we send beech leaf samples to the Cornell plant disease diagnostic clinic to confirm whether nematodes are present. After that we confirm new locations with photos of these symptoms.”
The ideal time to survey for the disease is late May through the fall. Partnerships for Regional Invasive Species Management – or PRISM — programs across the state, and the DEC are implementing a citizen science program to collect photos of leaf banding to determine where Beech Leaf Disease has spread.
NY Natural Heritage Program Invasive Species End User Support Specialist and iMapInvasives Project Team member Mitchell O’Neill said photos of suspected diseased leaves should then be uploaded to New York’s iMapInvasives for positive identification.
“Good photos are super, super important. So like if you take a picture of a beech leaf from the top you can’t really tell if it has beech leaf or not. But if you take a really nice focused picture from the bottom with the sun coming through the leaf then it’s much easier to be able to tell whether it’s beech leaf disease or something else. And it’s really important to record those non-detected surveys. So if you go out looking for beech leaf disease and you don’t see it please document that, because that’s really helpful for us to see.”
Maria Moskalee has been working with the Lower Hudson PRISM to survey for Beech Leaf Disease.
“Pretty much every beech tree that they see has it unfortunately. It’s really bad. It just rapidly spreads. And also it’s in the trees before they show symptoms.”
