“The Walnut Twig Beetle (WTB), Pityophthorus juglandis, the insect involved in Thousand Cankers Disease of Black Walnut (TCD), has been detected in Indiana for the first time at a Franklin County sawmill.

The beetle was detected in a trap placed at the sawmill for a 2014 statewide survey for WTB. Additional WTBs were found during an inspection of walnut logs and lumber at the sawmill. TCD is caused by the fungus Geosmithia morbida that is transmitted by WTB.

The beetles bore into walnut branches, feeding on the tree’s 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 destroy the tree’s ability to transport water and nutrients. Gradually the tree dies.

Tests for the fungus from the collected beetles and walnut samples in Franklin County are ongoing. So far, the fungus has not been detected. Surveys at the sawmill have not detected any infested walnut trees. Another survey is planned for this summer for the area surrounding the sawmill.

State Entomologist Phil Marshall has ordered the sawmill quarantined. The sawmill is working with the DNR and is destroying walnut material on the property to prevent movement of TCD from the property.”

Note that no live trees have been found with TCD in Indiana yet. It is not recommended that landowners cut their walnut trees due to the disease. Instead, it is recommended that residents do not move firewood or other bark on materials of any species due to the risk of transporting known and unknown insects and diseases.

View Thousand Cankers Disease, Indiana Department of Natural Resources, for more information.

Resources
Walnut Anthracnose, Walnut Notes, U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station
Indiana Walnut Council, Industry Representatives include 45 states and 3 foreign countries
Diseases in Hardwood Tree Plantings, The Education Store, Purdue Extension resource center
Study: Fungus Behind Deadly Disease in Walnut Trees Mutates Easily, Complicating Control, Purdue Agriculture News
Thousand Cankers Disease, collaborative website
Walnut Twig Beetle and Thousand Cankers Disease of Black Walnut, Purdue Plant and Pest Diagnostic Laboratory
Indiana Walnut Council
Diseases in Hardwood Tree Plantings, The Education Store, Purdue Extension resource center
Why are my walnut trees dropping their leaves?, Purdue Extension – Forestry & Natural Resources (FNR) Got Nature? Blog
Invasive Species Walnut Twig Beetle Detected in Indiana, Purdue Extension – FNR Got Nature? Blog
Intro to Trees of Indiana: Black Walnut, Purdue Extension – FNR Got Nature? Blog
Planting Hardwood Seedlings in the Central Hardwood Region, The Education Store
Regenerating Hardwoods in the Central Hardwood Region:  Soils, The Education Store
Fertilizing, Pruning, and Thinning Hardwood Plantations, The Education Store
Resources and Assistance Available for Planting Hardwood Seedlings, The Education Store

Indiana Department of Natural Resources