The Virginia Department of Agriculture and Consumer Services (VDACS) officially confirmed a case of Thousand Cankers in Virginia. For several years, Thousand Cankers has been causing widespread decline and death of walnut trees in many Western states. This critical confirmation marks the disease’s first appearance east of Knoxville, Tennessee, where it was detected in 2010.
The discovery was made in Richmond, Virginia when two Bartlett Tree Experts arborists noticed decline and dieback symptoms consistent with the disease on a group of black walnuts on a client’s property.
According to the VDACS, Thousand Cankers is caused by a fungus that is vectored by the walnut twig beetle. Adult beetles bore through the bark and deposit eggs. As the larvae hatch, they tunnel through the tree, introducing the fungus and causing cankers under the bark. The result is branch dieback, decline, and eventual death of the tree.
Upon observing signs of Thousand Cankers, arborists Greg Crews and Alan Jones enlisted the assistance of Bartlett’s Plant Diagnostic Clinic at the Bartlett Tree Research Laboratories. The plant pathologists and diagnostic staff at the Clinic analyze over 8,000 plant samples each year and are one of only two private diagnostic labs partnered with the National Plant Diagnostic Network (NPDN).
“Knowing how important rapid detection and communication of the disease would be to help prevent its spread, we immediately contacted our Plant Diagnostic Clinic,” said Alan Jones, an arborist and Division Manager at Bartlett Tree Experts. “With their help in collecting samples from the declining trees, a positive identification was made quickly.”
Bartlett’s Plant Diagnostic Clinic worked closely with the VDACS to confirm the disease. As a result, the VDACS recently quarantined movement of walnut trees from Richmond and some neighboring counties in Virginia. Though it is possible that the disease will spread naturally, the quarantine will help prevent the artificial spread of Thousand Cankers, caused by transporting firewood, mulch or debris to uninfected areas.
This quarantine is a key step in protecting black walnut trees, an important native species of forest ecosystems in the Midwestern and Eastern U.S. As effective controls for the disease have not yet been developed, early detection and removal of infected trees is also recommended to limit spread. Property-owners concerned about their walnut trees should contact a certified arborist.
“Whether we’re helping one tree on a client property or working to protect a whole species, this is what tree care is all about.” commented Eric Honeycutt, a plant pathologist at Bartlett’s Plant Diagnostic Clinic. “It’s our ability to apply expertise, science and technology to help in the preservation of trees.”