by Holden Forests & Gardens
Beech leaf disease (BLD) is an emerging threat to North American forest ecosystems. It was first discovered in northeastern Ohio in 2012, and has already spread to 12 additional U.S. states and Canadian provinces. At first the cause of the disease was unknown, and the sick and dying trees were diagnosed on symptoms alone: Dark banding along the leaf veins and shriveled, leathery leaves. But in 2017, nematodes were found in diseased leaves, and by 2020 we had the answer: A newly recognized subspecies of the wormlike creature, Litylenchus crenatae mccannii, was definitely associated with the symptoms.