In the 29 years since a fungal disease known as butternut canker was first
observed in southwest Wisconsin, it has infected over 90 percent of butternut
trees throughout their native range from New Brunswick, Canada, to Georgia to
Dale Bergdahl, recently retired after 29 years as a University of Vermont
forestry professor, has been tracking more than 100 butternut trees here in the
University of Vermont’s Jericho Research Forest.
Dr. Bergdahl was the first to find the canker in Vermont, near Snake Mountain,
in the fall of 1983. Since then, it has killed half the butternuts in the state.
The fungus, Sirococcus clavigignenti-juglandacearum, was described as a new
species in 1979 and bears the earmarks of being recently introduced. But it has
never been found outside North America.
Dutch elm disease and chestnut blight, also caused by fungi, were notorious, and
much more conspicuous, because elms and chestnuts were ...