A honey-brown colored mushroom develops in the autumn on the roots or buttress of infected trees. The spores liberated from the mushroom are windblown to other areas. Top growth of the infected tree slows, branch dieback occurs, and roots rot. Trees may appear to die quickly. White fans of fungal growth are found when bark is peeled off infected trunks near the soil line.
Conifers have abundant resin flow from the trunk at the soil line.
Irrigate to relieve drought. Protect plants against injuries to the lower trunk and upper portion of the root system. Do not replace an Armillaria -killed plant with another woody species.