Originally identified in Colorado, TCD affects many types of walnut trees to varying degrees but is typically lethal to black walnuts in the western states. The decline of the walnut in western states has caused concern in the Midwest about TCD. In Indiana walnut trees are often grown in plantations and they are also 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 that blend together and destroy the tree's ability to transport water and nutrients. Gradually, branches die, and then the entire tree.
In western states, walnut trees affected by the disease typically die within two to three years after symptoms are noticed. However, one study monitoring walnut trees with TCD in Virginia and Tennessee reported trees that seem to be recovering from symptoms of dieback. Preliminary reports seem to show that — at least in the Midwest and East— the development of TCD in walnut trees coincides with an additional stress event, such as drought.
Geosmithia morbida was isolated from a native weevil, Stenomimus pallidus in a black walnut plantation in Yellowwood State Forest in Brown County in December 2013. This was the first time the fungus was detected on an insect other than the walnut twig beetle. Geosmithia morbida has not been detected in any other location in Indiana.
The walnut twig beetle was detected in Franklin County in samples collected during the 2014 trapping season. This is the first detection of walnut twig beetle in Indiana. The detection was from a trap and also from logs at a sawmill.
The TCD disease complex of Geosmithia morbida and the walnut twig beetle has not been found together in a living tree in Indiana. 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, such as sawmills, concentration yards for log buyers, solid waste sites and other woodworking sites.
Please contact your local nursery inspector with questions, concerns, or possible find of this insect/disease complex.
Indiana Quarantine Information
Moving walnut material inside Indiana
Movement of black walnut within Indiana is not restricted.
Transporting walnut material OUT of Indiana
Upon the discovery of the fungus Geosmithia morbida on the Stenomimus pallidus beetle in Indiana, a few states began to quarantine walnut material being transported out of Indiana. Since then it has been determined that the native beetle Stenomimus pallidus is not an effective vector of TCD. Upon that determination most states have removed or are in the process of removing the quarantine of walnut materials originating in Indiana. 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.
- Indiana Thousand Cankers Disease Updates and Shipping Requirements (August 2015)
- Thousand Cankers Disease Final Rule (May 22, 2013)
- Determination for Thousand Cankers Disease Temporary Rule (Updated January 23, 2013)
- Emergency rule aimed at stopping tree disease (August 31, 2010)
- Walnut Twig Beetle detected in Indiana (April 9, 2015)