LANSING, Mich. – Beech leaf disease has been added to Michigan’s invasive species watch list and state officials are asking residents to be on the lookout for trees infested with the damaging disease. Beech leaf disease is associated with a microscopic worm that enters and spends the winter in leaf buds. It causes damage to leaf tissue on American beech and European and Asian beech species resulting in darkened, thick tissue bands between leaf veins, creating a striped effect on the leaves, leaf distortion and bud mortality. Michigan is home to about 32 million American beech trees. “Many questions about beech leaf disease remain unanswered,” said Simeon Wright, a DNR forest health specialist.