ANNAPOLIS, MD (June 9, 2025) The Maryland Department of Agriculture has confirmed worsening symptoms of beech leaf disease throughout the State in counties including Allegany, Anne Arundel, Baltimore, Caroline, Carroll, Cecil, Charles, Frederick, Harford, Howard, Montgomery, and Washington and Baltimore City. Beech leaf disease and the associated nematode Litylenchus crenatae maccannii, a microscopic wormlike animal that lives inside the trees leaves and buds, affects all beech species including American beech (Fagus grandifolia). The disease has also been found in surrounding states including Pennsylvania, Virginia, West Virginia, Delaware, New Jersey, Ohio, Michigan, New York, Connecticut, Massachusetts, Rhode Island, New Hampshire, Vermont, and Maine.
Beech leaf disease affects and kills native and ornamental beech tree species. During the winter the nematode will consume the tissues inside of the bud causing damage. Beech leaf disease symptoms can occur at any time of the year and are best viewed from the underside of the leaf. Symptoms include leaf striping, curling, leathery texture, reduced leaf and bud production. Young trees can be killed within one year of infection and mortality for mature trees is estimated between 6-10 years.
Currently there is no known way to prevent nematode infection. Pruning trees in the winter or early spring can help increase light and air circulation to dry out the leaves and limit the nematode’s life. The use of fluopyram when applied during the nematodes movement from the leaves to the buds to overwinter was shown to kill over 90% of live nematodes. Treatment should occur in the late summer during a time when the leaves are wet. Another treatment with proven effectiveness on smaller size class trees is a PolyPhosphite30 fertilizer. This product is used during the growing season as a soil drench or soil injection which will stimulate the tree’s immune system. Landowners can contact licensed and certified pesticide applicators for treatment options. A list can be found at https://www.egov.maryland.gov/MDA/Pesticides. Additional information regarding treatments can be found at https://holdenfg.org/beech-leaf-disease/ or https://njaes.rutgers.edu/E376/ or https://web.uri.edu/coopext/wp-content/uploads/sites/2042/2024-BLD-update_9.23.24-1.pdf
Forest Pest Management continues to survey for Beech Leaf Disease in Maryland. Additional counties are being tested for presence of the disease and the nematode. Additionally, since 2019 permanent survey plots have been set up across Maryland. To report symptoms of Beech Leaf Disease, please use the Tree Health Survey app (https://treehealthapp) or via email to fpm.mda@maryland.gov. For additional information visit the UMD Extension Website at: https://extension.umd.edu/resource/beech-leaf-disease.
###
