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Originally found in Arizona, TCD affects many types of walnut trees to varying degrees but is lethal to black walnuts, which often are grown in plantations in Indiana but also are common in the state's urban and rural forests.
TCD is spread by walnut twig beetles carrying a newly identified fungus (Geosmithia morbida). Smaller than a pinhead, the beetles bore into walnut branches, feeding on the tree's bark tissues and depositing the fungus that creates a canker, or dead area, under the bark. Multiple feedings cause the formation of thousands of cankers under the bark and destroys the tree's ability to transport water and nutrients. Gradually, branches die, and then the entire tree.
Walnut trees affected by the disease typically die within two to three years after symptoms are noticed.
Thousand cankers diseases was detected on weevils in a black walnut plantation in Yellowwood State Forest in Brown County in December 2013. Geosmithia morbida was isolated from an insect – a native weevil, Stenomimus pallidus. This was the first time the fungus was detected on an insect other than the walnut twig beetle.
As of August 2014, this is the only known occurrence of TCD in Indiana. The walnut twig beetle has not been detected in the plantation or in any other location in Indiana. Geosmithia morbida has not been detected in any other location in Indiana.
Surveys are in place in the plantation to monitor and evaluate the detection. Visual surveys for the disease symptoms and trapping surveys for the walnut twig beetle are ongoing throughout Indiana with a focus on areas anticipated to be likely introduction points.
Moving walnut material inside Indiana
Due to the TCD find in Yellowwood State Forest, Brown County, the plantation has been quarantined. This restricts the movement of black walnut out of the plantation. Movement of black walnut within Indiana from other areas of Brown County and the rest the state is not restricted.
Transporting walnut material OUT of Indiana
Due to the TCD find in Indiana, other states have restricted the movement of Indiana walnut material into or through their states. These restrictions vary from state to state. Please contact an Indiana Compliance Officer for the most recent restrictions and to obtain a compliance agreement or state phytosanitary certificate to facilitate the movement of this material.
Transporting walnut material INTO Indiana
Indiana instituted an external quarantine in 2011 to protect our natural resources from walnut twig beetle and thousand cankers disease.
Walnut nursery stock, budwood, scionwood, logs, stumps, roots, branches, chips, and all species of nonconiferous (hardwood) firewood is restricted from entry into Indiana from the states of Arizona, California, Colorado, Idaho, Maryland, Nevada, New Mexico, North Carolina, Ohio, Oregon, Pennsylvania, Tennessee, Utah, Virginia and Washington.
Walnut nuts, nut meats, hulls, processed lumber without bark, kiln-dried lumber and finished wood products without bark are not restricted.
Please contact an Indiana Compliance Officer to obtain a compliance agreement for movement of regulated items or for more information about this quarantine.