Beech Tree Disease

Updated April 17, 2017

Beech tree disease is caused by small bugs called scales that cause a fungus to form under the bark of the beech tree. Both the bugs and the fungus are very harmful to a beech tree's bark, and may even cause the tree to die altogether.


The first time that beech tree disease was seen in North America was in Nova Scotia in 1890. Beech tree disease spread to Maine by 1932, and 40 years later it was rampant in the Hubbard Brook experimental forest in New Hampshire.

How it Spreads

This disease generally spreads through a large quantity of the scale insects that cause the initial nectria fungus to form. Once the scale insects and fungus have run their course, they die, and even though the disease may still be present in the forest, it is generally drastically reduced.

Trees it Affects

Beech tree disease tends to affect older trees, as it has the ability to get under the cracks in the bark. Younger trees, which have smoother bark, are less susceptible.

How it Works

Beech trees are generally susceptible to nectria fungus, but scale insects help the fungus get into the trees. The insects pierce the bark to feed upon it, and leave holes for the fungus to enter into. The fungus almost always kills both the insects and the bark.


Because there is not an effective way to kill the fungus, it is best to regulate the population of scale insects so that they do not cause the mechanism through which the trees is afflicted with fungus. A dormant spray of lime sulphur should take care of most of the insects, and therefore the disease.

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About the Author

Sara Tetreault has worked as a marketing copywriter and editor since 2006. She has written copy for public health organizations, Yankee Retail, and Oce North America. Tetreault received her Master of Arts degree in early modern culture and literature from the University of Sussex and obtained a dual Bachelor of Arts degree in English and communications from Eastern Connecticut State University.