Beech Bark Disease Control

Identification

• Beech bark disease requires the presence of two problems -- a scale insect and the fungus known as Nectria. Only when the scale insect has infested the beech is the Nectria fungus able to enter the bark. Nectria kills wooden areas on the trunk, making the trunk and branches more prone to snapping during wind storms. Trees typically succumb to beech bark disease within a few years of being heavily attacked by the scale.

Infestation Control

• Beech bark disease is difficult to control as both the scale insect and fungus are carried by the wind, in addition to being transported to the tree by birds and other wildlife. Humans can help control the spread of the disease by refusing to transport wood over long distances, especially from July through November. Prevention of beech bark disease by discouraging the spread of scale and Nectria is the ideal way to manage the problem.

Resistant Seedlings

• The planting of cultivars and beech seedlings resistant to scale and the Nectria fungus also helps to alleviate occurrences of beech bark disease. State entities like the Michigan Department of Natural Resources are working with federal authorities like the U.S. Department of Agriculture Forest Service Research to develop seeds and seedlings resistant to the disease. The spread of beech scale to new areas typically occurs at a rate of approximately 6 miles per year, at the time of publication.

Chemical Control

• Early detection of the beech scale is crucial in beech bark disease control. Horticultural oil and insecticidal soap may both be utilized to manage infestation by the insect and should be applied when the immature form of scale -- crawlers -- are present, normally between June and November. The effectiveness of the oil or soap is damaged if applied when the temperature exceeds 90 degrees F. The insecticide only kills scale that are present and is not a barrier against future infestations, according to the University of Tennessee Extension.