Beech leaf disease

Beech leaf disease is a newly discovered lethal disease of beech trees believed to be caused by the nematode Litylenchus crenatae mccannii.^[1] The symptoms of the disease appear as a dark green, interveinal banding pattern on the lower canopy foliage, eventually spreading throughout the tree. The symptoms appear to progress through the buds and no new leaves are produced. This eventually results in the death of the tree. The disease has the potential to drastically alter the Eastern deciduous forests of the United States on its own and through potential compounding disease effects.

Example of BLD on a beech leaf.

The disease affects the native American beech as well as the commonly planted European beech. The estimated economic and environmental cost of the loss of the beech in Ohio alone is $225 million. The disease has no known cure.^[2][3]

Cause

The disease is caused by a type of nematode that feeds inside the leaves. The nematodes feeding cause dark bands in the leaves. The worms are most damaging to young trees, which can die in less than five years after the first signs of damage appear. In places where the disease is established, it can prove fatal to 90% of saplings.^[4]

The U.S. Department of Agriculture Forest Service believes that insects, birds, as well as human movement are all possible modes of transport for the nematodes.^[5]

Disease range

Since its discovery in Lake County, Ohio in 2012, it has rapidly spread to 14 counties in Ohio, as well as to western Pennsylvania, Western New York, and Ontario, Canada.^[6] In 2020, it was identified in eastern New York, Long Island, Connecticut, Rhode Island, and Massachusetts.^[7] In 2021 it was found in Maine,^[8] in Lincolnville, Waldo County,^[9] and in Prince William County, Virginia.^[10]

See also

• Beech bark disease

References

1. "Beech Leaf Disease - NYS Dept. Of Environmental Conservation".
2. Wilke, Carolyn (January 22, 2019). "A Mysterious Disease is Killing Beech Trees". The Scientist. Retrieved August 28, 2019.
3. "Beech leaf disease is ravaging North American trees".
4. Kuffner, Alex (2020-09-14). "Microscopic worm poses big threat to R.I.'s beech trees". Providence Journal. Retrieved 2020-11-15.
5. Lambert, By Ben (10 June 2021). "Scientists: Beech Leaf Disease, potentially fatal for trees, widespread in CT". New Haven Register.
6. Popkin, Gabriel (July 28, 2018). "An Arboreal Murder Mystery What is Killing Beech Trees". Washington Post. Retrieved August 28, 2019.
7. Crowley, Brendan (2020-09-28). "Deadly 'Beech Leaf Disease' Identified Across Connecticut and Rhode Island". The Connecticut Examiner. Retrieved 2020-11-15.
8. "Beech leaf disease added to Maine's invasive species list after Midcoast confirmations". PenBay Pilot. 2021-06-07. Retrieved 2021-06-14.
9. "Invasive Threats to Maine's Forests and Trees: Forest Health & Monitoring". Maine Forest Service. Retrieved 2021-06-14.
10. "Beech Leaf Disease Confirmed in Virginia". Virginia Department of Forestry. 18 August 2021. Retrieved 2 September 2021.

Further reading

• Beech Leaf Disease in Massachusetts | Mass.gov