MDA takes steps to protect state’s walnut trees from deadly diseaseWalnut wood is no longer allowed into Minnesota if imported from 11 different states known to have thousand cankers disease (TCD).
By: Staff Report, Alexandria Echo Press
Walnut wood is no longer allowed into Minnesota if imported from 11 different states known to have thousand cankers disease (TCD). A temporary exterior quarantine announced in February was made permanent last week by Minnesota Department of Agriculture (MDA) Commissioner Dave Frederickson. The quarantine was issued as a preventative measure to help stop TCD from coming to Minnesota.
TCD is caused by a fungus carried by a tree pest called the walnut twig beetle. The beetle attacks the walnut tree, introducing the fungus while it tunnels under the bark. This results in small cankers, or dead areas, under the bark. As more beetles attack the tree, more cankers grow together and hinder the tree’s ability to move water, eventually killing it. To date, TCD has been found in Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Tennessee, Virginia, Washington, and Utah. The MDA quarantine restricts movement of products potentially harboring TCD from those states and from other potentially infested areas into Minnesota. Announcement of the formal quarantine comes within a month of the detection of TCD in the state of Virginia, which is only the second state within the native range of eastern black walnut to report the disease.
The list of products covered by the quarantine includes live walnut trees, walnut logs, walnut lumber, walnut nursery stock, wood chips and mulch made from walnut wood, walnut branches and roots, packaging materials made from walnut wood, and all hardwood firewood. The quarantine does not apply to walnut nuts, nutmeat, walnut hulls, finished products made from walnut wood without bark, or processed lumber that is 100 percent bark-free, and kiln-dried with square edges. Several other states within the native range of eastern black walnut have similar exterior quarantines in place.
“We are trying to protect Minnesota’s six million eastern black walnut trees and the state’s walnut timber producers with this quarantine,” said MDA Commissioner Dave Frederickson. “We have responded to several reports of walnut trees with unexplained dieback or decline, but there are no confirmed cases of thousand cankers disease in Minnesota.”
If TCD should occur in Minnesota, early detection is Minnesota’s best chance to minimize TCD’s impact. MDA is collaborating with the U.S. Forest Service and the Minnesota Department of Natural Resources in TCD survey work. MDA is asking for help in identifying walnut trees with unexplained dieback or decline. If suspect trees are spotted, please contact MDA’s Arrest the Pest Hotline (1-888-545-6684).
More information about TCD and the quarantine can be found on MDA’s website at www.mda.state.mn.us/plants/plantdiseases/1000cankers.aspx