Beech Bark Disease

Beech Bark Deisease is a canker caused by the fungus Nectria (Nectria coccinea var. faginata).  Beech scale (Cryptococcus fagisuga) is largely responsible for the spread of Nectria infection on beech trees.  The scale feeds on the tree causing wounds and weakening the tree.  The wounds are then infected by Nectria.  The scale and the Nectria work in combination to kill the tree.