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Quarantine ordered for walnut wood in Baltimore City and County to prevent spread of thousand cankers disease

The Maryland Department of Agriculture enacted a ban on the transfer of black walnut tree material in Baltimore City and parts of Baltimore County to prevent the spread of thousand cankers disease.

State agriculture officials ordered a quarantine Wednesday on walnut wood in an effort to prevent a blight that kills walnut trees from spreading beyond Baltimore and Baltimore County.

The quarantine, enacted by the Maryland Department of Agriculture, makes it illegal to move any walnut material or any hardwood firewood out of the quarantined area, which stretches across 185 square miles. The area encompasses all of Baltimore City and southeast Baltimore County.


It bans people from transporting nursery trees, grafts, green lumber and firewood, as well as living or dead walnut material including stumps, roots, branches and mulch.

The firewood quarantine applies to any type of hardwood firewood because it is difficult to distinguish between the types of wood. Walnut material cannot be moved beyond the quarantined area without a certificate of inspection for the blight.


The quarantine was placed into effect after thousand cankers disease was discovered in a Baltimore industrial area.

Thousand cankers disease is caused by a combination of a fungus, Geosmithia morbida, and walnut twig beetles, Pityophthorus juglandis. The beetles, which carry the fungus, tunnel under the bark of walnut trees and cause cankers to develop, which ultimately kill the trees within 10 years.

It’s the second time thousand cankers disease has been detected in Maryland since 2015.

The order, which lasts indefinitely, was added to a quarantine already in effect for Cecil County.

Maryland agriculture secretary Joe Bartenfelder said in a statement the quarantine aims to protect the local lumber industry from the disease and ensure surrounding states that Maryland walnut products are safe.

Breaking the quarantine could lead to civil and criminal penalties.