Southern blight is caused by the fungus Agroathelia rolfsii and is a destructive soil-borne disease that threatens plants in ornamental production and landscapes. First documented in 1911 on tomatoes in the southern US, this plant pathogen now infects more than 500 plant species, causing rapid wilting, stem rot, and eventually plant death. Once established in soil, managing this fugus becomes expensive due to the need for both labor-intensive practices and repeated fungicide applications.