Canker Diseases - Hardwoods
Beech Bark Disease
Beech trees with beech bark disease.
Cankered areas on beech caused by Neonectria vaginata (old name Nectria) coccinia var. vaginata. The small white flecks are the beech scale insect. Sporodochia and perithecia are produced on the cankered areas (not seen in this photo).
Beech scale insect (introduced into Canada and the US) make wounds on bark and Neonectria enters the wounds causing cankers.
Beech scale insects can be seen along with many small cankers.
Red perithecia of Neonectria form on the older cankers produce acsi and ascospores.
Higher magnification of the red perithecia formed on the cankered area.
As the disease progresses, more cankers develop and coalesce. Beech bark disease eventually kills the tree.