Beech leaf disease (BLD) was first discovered affecting American beech trees in Lake County in northeastern Ohio in 2012. Symptoms have been documented in at least a dozen northeastern Ohio counties and parts of Pennsylvania, New York, Connecticut, and Ontario Canada.
It has since been confirmed that the dark banding on leaves, leaf disfigurement, and branch dieback symptoms typical of BLD are linked to the presence of nematodes (microscopic worms) in the leaves and buds. American beech, European beech, and possibly other non-native species of beech are susceptible. In some areas, extensive mortality of understory beech seedlings and saplings has occurred.
Work is underway by multiple agencies and organizations to learn more about the damage BLD causes, how it spreads, and how it can be managed.