Beech bark disease (Ontario)

Beech bark disease is a lethal problem occurring in American Beech (Fagus grandifolia) throughout much of the native range of this tree species. The disease is caused by a complex of two pests. First, a scale insect (Cryptococcus fagisuga) infests the trunk and feeds by inserting a long mouthpart into the phloem; and second, fungal pathogens (Nectria coccinea var. faginata or N. galligena) infect the feeding wounds caused by the scale, leading to canker formation which eventually kills the tree.