Sclerotium diseases caused by Athelia rolfsii (Sclerotium rolfsii) include: base rot, crown rot, southern blight, collar blight
Athelia rolfsii is a soil-borne pathogen responsible for large economic losses across the world due to a broad host range, prolific growth rate and sclerotia as highly effective survival structures. More than 500 species from over 100 plant families are recorded as hosts world-wide including sunflower, legumes, maize, sorghum, cucurbits, wheat, multiple weeds and ornamental flowers. Although often a minor pathogen of sunflower, A. rolfsii is particularly damaging in tropical and sub-tropical regions where seasonal crops and weeds of the rotation may also become infected. A. rolfsii is heavily favored by hot temperatures, and distribution and severity of A. rolfsii has been increasing in countries such as Australia as temperatures increase.
The pathogen survives as small, pale to caramel brown sclerotia, resembling mustard seeds (Figure 1).
They survive in soil and crop (and weed) residues for many years and are the source of inoculum (Figure 2).