Beech Leaf Disease is has been found in every county in Pennsylvania.
This disease was first identified in Ohio in 2012 and is caused by a microscopic nematode that damages leaves while they are in buds over winter. Once leaves emerge in the spring, they remain damaged and will result in reduced vigor and over several seasons can result in the death of the tree. Often leaves will fall off giving the forest a very open appearance.
Since this disease is fairly new, effective treatments are fairly limited. The most effective treatments can be used on individual landscape trees, but are cost prohibitive on larger scales.