Contact: Donna Gilson 608-224-5130 donna.gilson@wisconsin.gov
MADISON – Wisconsin’s new restrictions are now in effect on plant and wood imports from areas infested with a fungal disease, part of a strategy to prevent introducing a pest that kills black walnut trees.
“The rule will protect Wisconsin’s black walnut resources,” explained Bob Dahl, plant protection section chief at the Wisconsin Department of Agriculture, Trade and Consumer Protection. “There are nearly 19 million black walnut trees in Wisconsin. State businesses export about $4 million in black walnut veneer logs and lumber annually.”
The new regulation took effect Aug. 1. It prohibits bringing plants, firewood and lumber that has not been kiln-dried into Wisconsin from states known to harbor thousand cankers disease. These states are Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Tennessee, Utah and Washington. Importers can get exemptions from the rule if they can certify that the material they want to bring to Wisconsin has not been exposed to TCD or has been treated. They may also get exemptions if they sign agreements with the Department of Agriculture, Trade and Consumer Protection that specify conditions.
Thousand cankers disease has not been found in Wisconsin. Its name comes from lesions, or cankers, that develop when the walnut twig beetle tunnels through the tree, spreading a fungus, Geosmithia morbidus. The tree’s foliage yellows and thins, and eventually the walnut tree dies. There are no known pesticides that will control this disease.
The disease can spread by firewood, nursery stock and unfinished or untreated black walnut products. It was first observed in New Mexico in the 1990s.
Wisconsin joins Indiana, Kansas, Michigan, Missouri, Nebraska, North Carolina and Oklahoma and Virginia in having a TCD quarantine.
