Beech bark disease impacts American beech (Fagus grandifolia) trees. The first step of infection is beech scale insects (Cryptococcus fagisuga) damaging vascular tissue and bark. The infestation may begin with a few insects that look like white wool on the bark. As time goes on the bark can be fully covered in scale insects. The insects weaken the trees’ structure and makes it susceptible to wind damage. Eventually the fungus (Neonectria coccinea) infects the weakened tree. After this occurs, leaf size is smaller and leaves are yellow. In the fall you can see red patches of the fungus on the bark in the form of a canker.
Check out our page on beech leaf disease to compare the signs and symptoms!
Have you seen this species? Report it to us or on the MISIN website or smartphone app! Please include a photo for ID verification.
Environmental Effects
Beech bark disease can become widespread in a forested area and reduce the species diversity. This can also lead to a reduction in wildlife habitat. The long-term effects of beech bark disease are still being researched.
Treatments
There are multiple treatment options for treating beech bark disease before the fungus infests the tree. There are chemical and non-chemical methods. Once the fungus has entered the tree there is very little that can be done.
NON-CHEMICAL CONTROL METHOD
- Blast water on trunk: high pressure water can remove the scale insects from the bark. This should be repeated throughout the year and in the following year as well. It does not prevent insects from gathering on the tree it just removes the ones currently on the tree.
- Selective removal of non-disease trees: if there are no scale insects present in a forested stand it may be effective to remove old or stressed beech trees to prevent them from being infested.
- Removal of infested trees: infested trees can be cut down to reduce the abundance of scale insects present. Note: if either removal method is chosen, the roots will sprout suckers which increases the density of beech trees. It is best to spray these with herbicide to reduce the abundance of beeches.
CHEMICAL CONTROL METHOD
- Insecticide: certain insecticides can be applied to the lower portion of the tree trunk or in the soil at the base of the tree. This will prevent scale insects from gathering on the tree. Note: this treatment should be performed yearly in the fall and spring to be most effective.
- Herbicide foliar spraying: if either removal method is chosen, the roots will sprout suckers which increases the density of beech trees. It is best to spray these with herbicide to reduce the abundance of beeches.