Wilted Plants? Check for Signs of Southern Blight

Southern blight on sage
Southern blight on sage. Photo: Dave Clement

Southern blight is a plant disease that is active now in hot summer weather. It is caused by a fungus called Sclerotium rolfsii. This fungus has a wide host range including woody plants, vegetables and herbs, and ornamental perennials such as coneflower, peony, and hosta.

Signs and Symptoms of Southern Blight

  • The first symptoms seen are wilting and collapse of individual stems or entire plants.
  • Close inspection of the stem at the soil line reveals white mycelium (strands of fungus growing on the stem and/or soil surface), and small, white or tan spherical sclerotia that resemble mustard seeds.
  • Roots of infected plants are unaffected. Decay of the stem at the soil line is common during hot, humid weather.

    Southern blight on banana pepper
    Southern blight on banana pepper. Photo: Gerald Holmes, Bugwood

How to Manage Southern Blight

  • The cornerstone for control of southern blight is clean-up of diseased plants in the garden.
  • Wilted and blighted plants and plant parts should be promptly removed from the garden.
  • Do not compost material killed by southern blight because the resting spores (sclerotia) of these fungi may survive the composting process.

Visit the Home & Garden Information Center for more information on Southern blight.

Have a question about ornamental plant care? Submit your question to Ask an Expert.

By Dave Clement, Principal Agent, University of Maryland Extension, Home & Garden Information Center

Leave a Reply