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Beech leaf disease: An emerging forest threat in Eastern U.S.


A woman holding a leaf while standing next to a tree in the forest
Danielle Martin examines a healthy beech leaf while searching for signs of beech leaf disease in West Virginia forests. Photo courtesy of Brianna Shepherd , Holden Arboretum.
 

WEST VIRGINIA—Forest health managers in the Eastern and Southern Regions are working diligently to assess and manage an emerging threat to forests in the Eastern United States and Canada called beech leaf disease.
The disease kills and causes dieback of American beech trees in North America. Early signs of BLD include dark stripes or bands between lateral veins of leaves in the spring.

BLD was first detected in the United States in Lake County, Ohio in 2012. It is caused by a microscopic worm, or nematode, that was recently discovered.

“Scientists are also examining other bacterial associations,” said Danielle Martin, an Eastern Region forest pathologist in West Virginia.
Beech tree saplings infected with BLD usually die within five years of infection. Mature trees tend to take several years to die of the infection.
Martin described how BLD kills beech trees. “We believe that the nematode initially infects buds. Infected buds become dry and cracked but tend to stay on the branch. Infected buds will not leaf out the following spring, leading to branch dieback and loss of canopy cover.”

Since its discovery, BLD has been detected in 13 states, including Ohio, Connecticut, Delaware, Maine, Massachusetts, Michigan, New Hampshire, New York, New Jersey, Pennsylvania, Rhode Island, Virginia, West Virginia and the Canadian province of Ontario.

“The rate of spread and new detections is very concerning,” said Martin. “The advancement of symptoms within tree stands is extremely high. In only a few years, infections will progress from mild symptoms to mortality of the understory. Although research is ongoing, we believe it’s a nonnative species.”

A leaf in front of a canopy of trees
Close up of a beech leaf showing symptoms of beech leaf disease. Courtesy photo Connecticut Agricultural Experiment Station via Bugwood.org by Yonghao Li.

Martin also shared that the Forest Service has funded multiple projects looking at distribution, spread, vectors, detection techniques and treatment options.

Nearly a dozen agencies and organizations are collaborating with the Forest Service on this issue. They include Holden Arboretum, Cleveland Metro Parks, Pennsylvania State University, USDA Agricultural Research Service, West Virginia University, Connecticut Agricultural Experiment Station, the Ontario Ministry of Natural Resources and Forestry as well as several other state agencies.

“We’re researching different means to mitigate the problem,” Martin added. “We don’t have a good solution on treatment yet. Our partners have had some success with a chemical used to fertilize turf grass, PolyPhosphite 30. We suspect it increases resistance in the tree. We’re not sure if it’s directly affecting the nematode in some way, or if it’s just increasing resistance to BLD.”

Martin said more funding is needed, along with a lot more research.
Beech nuts are important for wildlife, particularly for bears. The Forest Service has several pest alerts available, including one for BLD.

 

Sustain Our Nation's Forests and Grasslands
https://www.fs.usda.gov/inside-fs/delivering-mission/sustain/beech-leaf-disease-emerging-forest-threat-eastern-us