I tend to follow the news about North American diseases of trees ever since I got interested in the case of the American Chestnut back in the 90s. I'm a casual, interested observer. I had heard about the disease that was impacting the Black Walnut trees west of the Rocky Mountains in the early 2000s. It seems that the trees, which originally came from the eastern forests of the U.S., had no natural immunity to the local flea-sized pest, the twig beatle, or more importantly, to the fungus that this little beatle carries from tree to tree.
It's depressing to realize how little knowledge, particularly in treatments, we have of tree diseases. Right now, tree disease or insect infestations are devastating the global populations of black walnut trees, elms, ash trees, butternut, Japanese larch, some European oak trees, and many others. The only defense proposed by the foresters in the United States to the walnut disease, otherwise known as Thousand Cankers Disease, is to attempt to quarantine the infected black walnut populations of the west coast, to keep it away from the valuable and widespread Walnut groves in the Eastern United States.
I hadn't heard until today, that the disease has already made the jump. It evidently popped up in Tennessee as early as 2010. But as with all things tree related, movement is slow. Even verification is slow. And in late 2012, the disease was also detected in Butler County in my own native state of Ohio. This is horrible news. The black walnut tree population, so valued by woodworkers in North America may be doomed. And this is probably the nail-in-the-coffin for the butternuts, who were already devastated by their own special disease in earlier decades. The disease seems to be close to 100% fatal to the juglans nigra (Black walnut) species.
The only good news seems to be that the disease is spreading more slowly in the Eastern States than it did in the West. But this is a faint hope, since the beatles are very hard to block or prevent, and there doesn't seem to be any near term hope for an effective treatment.
As in almost all of these stories about tree diseases, there are three actions the arborists and foresters attempt, in declining order of frequency: quarantine, disease vector blocking, and finally, biological treatment of the underlying disease. It's odd to me that the last is the one tried least often. It's not surprising, I guess, since science knows so little about the world of plant disease, at least compared to the world of animal disease. These stories always tack on a last paragraph that the most hope that can be gleaned about the future of the tree species in question is a hybrid anti-fungal/insecticide dual attack on the disease. The problem, I guess, seems to be that we don't have good ways to administer these treatments.
Still, it is imporant to say, IF YOU HAVE BLACK WALNUT LUMBER OR WOOD, ESPECIALLY WITH THE BARK STILL ON, DO NOT TRANSPORT IT ANYWHERE. NOT EVEN A COUPLE OF MILES IN ANY DIRECTION!!!