LANSING, Mich. (WJRT) – A microscopic worm that threatens to kill Michigan's 37 million American beech trees appears to be spreading around parts of Metro Detroit.
The Michigan Department of Natural Resources says the Litylenchus crenatae worm, which spends the winter in leaf buds, was first detected in St. Clair County last July. New outbreaks have been identified in Oakland and Wayne counties since then.
Infected trees have been discovered in Birmingham, Bloomfield, China, Clay, Grosse Pointe Shores, Rochester and Troy. State forestry officials believe the infestation has been in those locations for at least a year.
“We’ve now seen beech leaf disease in both woodlots and individual urban trees in southeast Michigan,” said Simeon Wright, Michigan Department of Natural Resources forest health specialist.
The worm causes leaf damage to all species of beech trees and makes them vulnerable to other tree diseases. Beech trees infected with the invasive worm can die within six to 10 years, and no treatment is available.
“The disease causes dark, thick bands between leaf veins, which can be seen on green and brown leaves,” said Wright. “If you have beech trees, take time now to look for symptoms.”
The DNR says Michigan's American beech trees are already under attack by the fatal beech bark disease.
“Though beech leaf disease was detected this spring, the condition of the leaves and number of trees affected at this location suggests the disease has been there for more than a year,” said Simeon Wright, DNR forest health specialist. “Because symptoms are slow to emerge, it is difficult to detect the disease before it is established.”
Beech leaf disease was first identified in the U.S. in Ohio back in 2012. The tree illness has been discovered in eight other states and Ontario.
Scientists continue investigating beech leaf disease, the Litylenchus crenatae nematode and the potential effects on Michigan's forests. They are not sure whether the worm causes the damage or whether they carry another organism that infects beech trees.
“Because of this, we don’t yet know how the disease might be spread,” said Wright. “Currently, there are no known treatments to protect trees or reduce disease impacts, although trials are ongoing.”