Thousand Cankers Disease (TCD) Thousand Canker Disease (or TCD) is possibly the greatest threat to black walnut trees here in Murfreesboro TN. Spread by a twig beetle, this disease is caused by a fungal infection that spreads on multiple contacts with the carrier insect. This particular disease, as it is so contagious, is a serious danger to black walnut and other trees as well, causing certain counties and areas to be under quarantine. The best way to keep the disease from spreading is to never transport wood from one area to another: always use wood from a local source, and never store firewood in your home! Murfreesboro TN Tree Service http://murfreesborotntreeservice.com/ See previous post: https://posts.gle/UNxx3v