Also known as the European beech, Fagus sylvatica is native to Europe and has dark green foliage with a reddish tint. This beautiful tree does not do well in moist environments, which leave it susceptible to fungi. Fungi and insects can cripple the copper beech, weakening and killing it, or causing unsightly brown and curled leaves.
Beech Bark Disease
In the United States, beech bark disease is caused by beech scale, a soft-bodied insect that feeds on the trees. Beech scale leave a white, waxy substance behind and weaken the bark of the tree, leaving it exposed to the fungus Nectria galligena. Nectria will continue to eat through the tree, eventually killing it.
Bleeding Canker Fungus
Bleeding canker fungus is caused by the fungus phytophthora, which causes reddish-brown, oozing dead spots as it eats through the tree. Eventually the fungus will weaken the tree and cause fatal breakage. According to Forestdamage.net, Cryptococcus fagi, a sap sucking insect is the precursor to this fungus. In Europe, a species called Phytophthora cambivora begins its destruction at the roots of the tree, working its way up to the bark at the base of the tree. The decaying matter is then eaten by honey fungus, tinder fungus and coral fungus.
Mostly cosmetic, powdery mildew disease leaves a white powder on existing leaves and new leaves grow crinkled and brown. Caused by fungus, powdery mildew does not significantly damage the tree and can be taken care of with a fungicide and improved circulation for the tree.
While insects are not diseases in and of themselves, beech trees do have sensitive bark and any damage done by insects can allow the harmful fungi nectria and phytophthora to invade. Beetles like bark beetles, wood-boring beetles, long-horned beetles and beech burprestid all bore into the bark and wood of the tree. Beetles can cut off sap flow and, as they tunnel through the tree, weaken its structure. Removing and burning infested trees quickly is important for stemming beetle infestations.
Differences in European Beech Bark Disease
In the United States beech bark disease is primarily caused by the damage from beech scale and the resulting Nectria galligena infection. In Europe beech bark disease tends to result from extreme weather and the resulting insect and fungi infestations. Again, the fungus phytophthora is a primary culprit, but infestation by the metallic wood-boring beetle also causes devastation.