Mullen, J. 2001. Southern blight, Southern stem blight, White mold. The Plant Health Instructor. DOI: 10.1094/PHI-I-2001-0104-01. Updated, 2006.

DISEASE:  Southern blight, Southern stem blight, White mold

PATHOGEN:  Sclerotium rolfsii (teleomorph: Athelia rolfsii)

HOSTS: more than 500 plant species including apple, peanut, potato, tomato; also many woody ornamentals, herbaceous annuals and perennials including aucuba, forsythia, azalea, hydrangea, viburnum, ageratum, begonia, columbine, coneflower, marigold, pansy, petunia, and zinnia.

Author
Jackie Mullen
Auburn University, AL

Southern blight, caused by the soilborne fungus Sclerotium rolfsii is a serious disease of a wide variety of plants, including field, vegetable, fruit, ornamental crops and also turf. S. rolfsii usually infects the lower stem near the soil surface. With some plants, the roots may become infected. The disease occurs worldwide, but predominantly in warm climates. In 1928, the USDA reported that S. rolfsii and root knot nematode caused more damage in the southern USA than any other pathogen. In recent years, southern blight has been especially damaging on cotton in Arizona, peanut and tomato in the Southeast, and sugar beet in California. Despite considerable research on this disease, control of southern blight continues to be a problem.

A viburnum trunk base infected by Sclerotium rolfsii. (Courtesy J. Mullen)