Death is normally preceded by yellowing and subsequent blighting of needles, defoliation, and heavier than normal cone production. Infection centers enlarge at the rate of 1 to 6 feet per year, reaching diameters of 60 to 100 feet. Rate of infection center expansion is much faster on former agricultural sites and in soils with a high pH. Since several symptoms produced by annosum root rot infected trees are nonspecific and can be brought on by other irritations, including other root rot fungi, positive field diagnosis depends on locating H. annosum basidiocarps. Basidiocarps are perennial and often located under litter at bases of dead or dying trees, under roots, and in stump cavities. Upper surfaces are tan to brown with distinct white margins, and lower surfaces are white.
Basidiocarps are rubbery and difficult to tear.
Even though basidiocarps are most common from December through March, their spores are produced throughout the growing season in the South. Evasion of the pathogen by planting on low-hazard sites. In low hazard sites depth to clay is less than 12 inches. Low hazard sites have poor internal drainage and high seasonal water tables. A high hazard site has 12 inches of sand or sandy loam above a clay subsoil with good internal drainage.