Beech leaf disease — a disease that has led to the destruction of beech trees from Ohio to southern New England — has been confirmed in Maine and added to the state’s invasive species list.
Landowners in Lincolnville observed possible symptoms of the disease and reached out to the Maine Forest Service pathologist, according to the Maine Department of Agriculture, Conservation and Forestry. The presence of the disease was confirmed by staff at the Connecticut Agricultural Experiment Station using leaf samples from a forest in Lincolnville.
The find is concerning to Maine’s tree experts.
“Beech trees are a pretty significant component of our forests in Maine and ecologically important to mammals, birds and insects,” said Aaron Bergdahl, state pathologist with the Maine Forest Service. “The leaves are high in nitrogen so the tree is important to soil nutrition.”
Beech leaf disease was first reported in Ohio in 2012, and for many years it was known only in adjacent states and nearby Ontario, Canada. In 2019, it was detected in eastern New York and by 2020 a survey and outreach effort found beech leaf disease in southern New England.
Symptoms of beech leaf disease include dark bands between the veins of beech tree leaves; curled, deformed and shriveled leaves; and trees with thin overhead canopy. At its worst, beech leaf disease can kill both American and European beech.
It is not the same thing as beech bark disease which is found throughout Maine.
The Lincolnville landowners’ observation and close attention during frequent walks on their woodland led to the discovery of beech leaf disease in Maine, Maine conservation officials said.
The leaf disease appears to be widespread in the midcoast and has been seen in towns between Belfast and Rockport and inland to Searsmont and Hope, according to the Maine Forest Service. It’s unknown how it spreads, but the forest service said that the areas where it’s being found didn’t show evidence of it in 2020.
The leaf disease is associated with a plant parasitic nematode — or small worm — according to the New York Department of Environmental Conservation. The nematode attacks trees of all ages and the disease can kill mature trees in under 10 years.
However, that’s likely not the only cause, Bergdahl said.
“The nematode alone does not seem to be responsible,” Bergdahl said. “But the nematode is consistently associated with the disease symptoms, so it is widely accepted that it is part of the disease complex.”
That gives beech leaf disease something in common with beech bark disease, a fungal disease that attacks beech trees. The fungus enters the bark after the tree becomes infested by tiny scale insects that create holes in the bark as they feed. Once the fungus enters the bark, it can kill a mature tree in six years.
Some beech trees in Maine are resistant to birch bark disease and Bergdahl fears those trees may fall victim to the leaf disease.
There is no proven method of managing beech leaf disease.
The Maine DACF is asking for the public’s help in identifying additional areas impacted by the invasive disease. Anyone who suspects seeing affected leaves should report them to the Maine Forest Service. Photos of the leaves can be submitted using the Maine Forestry Service tree ailment form, emailing email@example.com or calling 207-287-2431.
Any photos should include a clear shot of the underside of the affected leaf or leaves.