Joseph O’Brien, USDA FS, bugwood.org

Armillaria Mushrooms

Root disease increases trees’ susceptibility to other pests, especially bark beetles, fire and windthrow.

It’s important to consider the root diseases present in a forest stand before beginning fuels reduction thinning or harvesting operations.

Habitat type, soil conditions and climate all affect root disease incidence and severity.

Forest Service researchers study many of the fungi that cause root disease, such as Armillaria spp, and Heterobasidion spp.