Rolf's disease

The fungus produces effused basidiocarps (fruit bodies) that are smooth and white. Microscopically, they consist of ribbon-likehyphae with clamp connections. Basidia are club-shaped, bearing four smooth, ellipsoid basidiospores, measuring 4-7 by 3-5 μm. Small, brownish sclerotia (hyphal propagules) are also formed, arising from the hyphae.

Athelia rolfsii occurs in soil as a saprotroph, but can also attack living plants. It has an almost indiscriminate host range, but its capacity to form sclerotia (propagules that remain in the soil) means that it particularly attacks seasonal crops. It mostly occurs in warm soils (above 15°C) and can be a serious pest of vegetables in tropical and subtropical regions (including Florida, where it was first recognized), causing "southern blight".