Maryland Quarantines Cecil County Walnut Trees. Disease Found.

The Maryland Agriculture Department says it’s now illegal to move any walnut material and hardwood firewood out of a 21 square mile area in the northeast corner of Cecil County. They found Thousand Cankers Disease (TCD), which until now was confirmed in western states. 

It’s a fungus carried by the walnut twig beetle. The bug found its way to one section of Maryland, an area bounded by the Pennsylvania and Delaware state lines, I-95 and MD Route 213. (see the red dot in the map below)

2014 Maryland Walnut Twig Beetle Traps
Map courtesy Maryland Department of Agriculture

“MDA believes the Fair Hill site is an isolated infestation,” said Agriculture Secretary Buddy Hance. “The quarantine prohibits the movement of potentially infested material out of the area, and helps to reassure neighboring states that Maryland walnut products do not carry the disease.”

Due to the difficulty in distinguishing between species of hardwood firewood, all hardwood firewood from the area is considered quarantined. All walnut material without a certificate of inspection for this pest is restricted, including nursery stock, budwood, scionwood, green lumber and firewood. It also covers other walnut material that is living, dead, cut or fallen, including stumps, roots, branches, mulch and composted and uncomposted chips.

Thousand Cankers Disease
Photo by Joe Boggs of the Ohio State University Extension
Walnut twig beetles
Walnut twig beetles on a penny (photo courtesy The Ohio State University Extension)

Nuts, processed lumber and finished wood products without bark are exempt from the quarantine.

The walnut twig beetle, a dark brown bug about the size of a poppy seed, tunnels under the walnut tree’s bark, causing a canker. As the beetles and cankers grow, they slowly starve the tree of nutrients. The walnut tree is typically dead within 10 years of initial infestation.

The leaves start to yellow and thin out in the upper crown of the tree. Larger limbs die as the disease progresses, eventually killing the trunk. Once the crown starts to turn yellow, the tree is dead usually within three years.

Signs of Thousand Cankers Disease in Black Walnut trees
Walnut leaves that have collapsed and wilted, signs of Thousand Cankers Disease hitting Maryland’s Black Walnut trees (Photo courtesy Curtis Utley, Colorado State University Extension)

One way the beetle might have come to Maryland is by firewood or logs brought from other states. Campers and homeowners are encouraged to use only local firewood and burn it all. Don’t transport it.

The disease was first discovered in Maryland in October. Officials say there’s no effective treatment for TCD.

Several Pennsylvania counties are also quarantined. Movement of walnut material and hardwood firewood are limited from states known to have Thousand Cankers Disease including Arizona, California, Colorado, Idaho, Indiana, Nevada, New Mexico, North Carolina, Ohio, Oregon, Tennessee, Utah, Virginia, Washington, and now Maryland.

Here’s more information about TCD nationwide.  

People who suspect they have seen thousand cankers disease or walnut twig beetles should contact their local county extension office or call 410-841-5870 Visit for more details.


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