Fungal diseases threatens Michigan's walnut, butternuts

Capital News Service
LANSING — Most butternut trees in the Great Lakes region are dead — victims of an as-yet unstoppable fatal fungus — and the survivors may be doomed as well, leaving a hole in the diversity of the region’s hardwoods. Butternut canker has killed an estimated 90 percent or more of Michigan’s butternut trees — also known as white walnuts –for example, said Mike Ostry, a research plant pathologist who studied the fungus from the 1970s until last May, when he retired from the U.S. Forest Service’s Northern Research Station. “In some respects, butternut canker is far more serious than the chestnut blight in what it does to its host,” he said. The cankers are elongated sunken areas in branches, trunks and exposed roots, according to a study published by Purdue University Extension. As the disease advances, it girdles and kills the tree.