The disease on your beech tree, unfortunately, may be beech leaf disease. This is a very distressing disease of American and European beech trees, particularly as little is known about transmission and thus how it can be prevented.  Current research suggests that it affects the ability of beech trees to photosynthesize and is associated with the nematode, Litylenchus crenatae. There is some disagreement about the additional factors associated with the disease as affected leaves have also been found to carry a fungus and species of bacteria. Some scientists believe that multiple elements need to be present in concert and others that the nematode is able to infect the plant on its own. You can learn more about foliar nematodes in this fact sheet from Missouri Botanical Garden. When you suspect a tree on your property has beech leaf disease, you should have your county's Cooperative Extension test the leaf in their diagnostic lab to confirm the problem.

The disease was first detected in Ohio more than a decade ago and has moved eastward since then. It is not yet known what the average pace of decline will be for mature beech trees, but a recently published study by Brianna L Shepherd., David J. Burke, and Katharine L. Stuble at Holden Forests & Gardens in Ohio concludes that 30% of the native beech trees in its area have died since beech leaf disease was detected there in 2014, with a dramatic increase in the rate of decline in the last 3 years. Other beech trees in the affected plots grew more slowly than is typical. Areas most densely populated by beech trees suffered the greatest rate of mortality. The disease progresses slowly, starving the tree of some necessary energy each year, and young trees can die within five years.

I am sorry to say that there are no curative management strategies yet. Research is underway and some promising experimental treatments are being investigated. A foliar drench applied by a professional to an entire tree canopy with precise timing in late summer has shown effectiveness at reducing the presence of nematodes. The Holden study found that areas where soil had been amended with phosphate or lime showed somewhat lowered rates of mortality, suggesting that soil chemistry may play a role in beech leaf disease and its management. Other anti-fungal and anti-parasitic applications to the roots are being studied. This fact sheet from The New York Department of Environmental Conservation is a good synopsis of the current state of investigation and control efforts.

Both iNaturalist and Map Invasives NY are collecting data on areas of infestation which is critical in the effort to learn how the disease is spread and create management tools. You can access the iNaturalist Bust Beech Leaf Disease EcoQuest website here and New York's Map Invasives reporting tool here. You can find a map of reported observations of beech leaf disease from iNaturalist here.

Courtesy of NYBG Plant Information Service