Will scientists finally defeat deadly chestnut blight?

St. Paul, MN (June 24, 2002) -- Hope lies on 90 acres of unglaciated hillside in western Wisconsin. That's where researchers have attempted to slow the movement of chestnut blight on more than 3,000 trees, originally planted in the 1880's. Chestnut blight, a devastating disease that caused one of the country's worst environmental disasters, arrived at this stand in 1987 and has been the focus of a biological control study ever since. Scientists from around the world will tour the site in July as part of the Annual Meeting of the American Phytopathogical Society (APS), an international association of scientists who study and manage plant diseases.

One of the deadliest diseases ever imported, chestnut blight struck American chestnut trees with a vengeance. "These were giant trees, measuring 80 to 120 feet in height," says Jane Cummings Carlson, a scientist with the Wisconsin Department of Natural Resources and local coordinator of the Wisconsin research project. "Within fifty years of its discovery in 1904, chestnut blight had virtually destroyed more than 3.5 billion trees, driving the American chestnut to near extinction."

Long appreciated for their beauty and prized as a source of lumber due to their rot-resistant wood, American chestnut restoration has been a long-term goal of scientists.

In the last two decades, scientists have attempted to debilitate the fungus by infecting it with a virus, a process called hypovirulence. Hypovirulence gives chestnut trees a much less potent form of the disease and gives chestnuts a fighting chance for survival. Once introduced into a few trees, hopes are that hypovirulence will spread throughout the forest, offering hope to surrounding trees as well. Whether hypovirulence can ultimately help save what remains of the American chestnut is yet to be seen. "There's a lot riding on this," states Cummings Carlson. "It's our hope that hypovirulence will enable us to save the trees we have left and provide favorable conditions for new trees to grow."

In addition to the Wisconsin site, researchers in other parts of the U.S. have been experimenting with hypovirulent strains. Reports on whether or not they've faired equally as well as the Wisconsin project will be part of a special symposium "Chestnut Blight: A Ten-Year Study of Disease Management Using Hypoviruses," which will include a tour of the Wisconsin research site.

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