In 2008, this new disease was recognized by researchers in Colorado. It is caused by a fungus, Geosmithia morbid, that is transmitted by small twig beetles. Tree mortality occurs after two to three years after infection. Confirmed populations now have been through the states of Washington, Oregon, California, Idaho, Utah, Colorado, and most recently Tennessee. The infected counties in Tennessee have had an emergency quarantine. The Thousand Cankers Disease spread is helped by the movement of walnut wood with the bark still on (logs, firewood, etc.). It also can spread naturally, but at a slower rate.
This is all troublesome news to us. Black walnut is the most valuable tree species in the Midwest. Many landowners have invested their money and hard work into plantations of black walnut. Researchers are currently working hard to come up with ways to save our valued trees. No solution has been found yet. The best thing to do is stay informed on the current information. Also be sure to inspect your woods regularly to see how the health of your trees are doing.