INDIANAPOLIS (AP) — A deadly tree fungus that's been detected for the first time in Indiana poses a real threat to the black walnut trees that are the state's most valuable tree, the state entomologist said Friday.
Small insects called weevils that emerged from two stressed trees at a black walnut plantation in southern Indiana's Brown County were found to be carrying the fungus that causes thousand cankers disease. That plantation, in the Yellowwood State Forest, has been quarantined by state officials.
The fungus affects many types of walnut trees, but it is lethal within a few years to black walnut trees, a valued tree that in addition to producing richly flavored nuts is used for flooring, millwork and veneer for furniture.
Although the two trees where the weevils were found aren't infected with the disease, State Entomologist Phil Marshall said officials are keeping a close eye on that plantation and surrounding black walnut trees for signs of infection.
He said the discovery of the fungus on the weevil marks the first time that pathogen has been detected on an insect other than the walnut twig beetle, which transmits the disease.
"It's not a serious situation, but it's a matter of very important concern. We've found it and we've found something unusual and different from what is known about this disease complex right now," said Marshall, director of the state Department of Natural Resources' division of entomology and plant pathology.
He said the DNR, the U.S. Forest Service and Purdue University are conducting additional studies at the plantation to better understand the disease and the insects there. The fungus was discovered during a survey for insect pests and fungi in Indiana and Missouri led by the U.S. Forest Service.
Indiana now joins Maryland, North Carolina, Ohio, Pennsylvania, Tennessee and Virginia among the eastern and central states where the disease has been found. It has also been found in eight western states — Arizona, California, Colorado, Idaho, New Mexico, Oregon, Utah and Washington.