Disease Directory

    Southern Blight

    Sclerotium rolfsii (Athelia rolfsii)

    Fungus
    Stems
    Roots
    Whole Plant

    Overview

    A soil-borne fungal disease common in warm climates that attacks the base of stems, causing a white, fan-like mycelial growth and small, round sclerotia resembling mustard seeds.

    Symptoms

    White, fan-like mycelial growth at the base of stems at the soil line. Small (1-2mm), round, tan to brown sclerotia (resembling mustard seeds) in the mycelium. Wilting and collapse of plants. Stem girdling at soil level.

    Environmental Conditions

    Hot

    Prevention

    Rotate with non-host crops (grasses, corn). Deep plow to bury sclerotia. Avoid excessive mulch near stems. Maintain good air circulation. Solarize soil in summer.

    Management

    Remove infected plants and surrounding soil. Apply biological controls (Trichoderma). Lime soil to raise pH above 7.0. Deep tillage to bury sclerotia. Fungicide drenches around plant bases.