Beech leaf disease

Febuary 20th, 2023

Beech Leaf disease is an invasive disease that causes dark stripping, disfiguration and a thick, leathery

appearance. It is a fungus disease, known to be caused by microscopic worms called nematodes that

infest the tree. The disease slowly kills the tree over time after the initial infection. Smaller trees

infected usually live for three years after symptoms appear and mature trees can live seven years after

being infected.

Researchers have tested and proven a treatment that they will be expanding to many beech trees in the

Cleveland Metroparks which contains 18 nature reserves.

One treatment that has been working very well is PolyPhosphite 30. This chemical is injected into the

soil beneath the trees to treat beech leaf disease without causing harm to the environment. It has been

proven that trees after 5 years of research treated with PolyPhosphite 30 have highly decreased

symptoms.

The other effort that the Cleveland Metroparks has introduced is two insecticides that treat beech leaf

disease. These insecticides are being directly injected into the stem of the beech leaf tree in order to

prevent the nematodes from harming other trees. There are not yet enough proven results for the

insecticides as it is in the beginning stages of trials, and as of yet, to be approved to be used by arborists.

PolyPhosphite 30, however, is expanding into areas beyond Cleveland Metroparks. There is a growing

concern as the disease has been found in Pennsylvania, New York, Connecticut, New Jersey, Virginia,

West Virginia, Massachusetts, Rhode Island, Maine and Ontario.