USDA Forest Service Forest Health Protection, Southern Region Annosus Root and Butt Rot, caused by Heterobasidion annosum Importance.
All southern pines are susceptible, but loblolly and slash pine are most severely affected.
Identifying the Fungus. Conks, when fresh, are tan to brownish on the upper surface and white with tiny pores on the lower surface. They are rubbery and tough to tear. In the southern United States, conks are most common from December through March. Identifying the Injury.