Sclerotinia blight is a plant disease that causes wilting then death of the purple coneflower. Signs of the disease include dark brown or black lesions at the soil line and just above. The roots are rotted and black.

Here are some ways to treat it:

• Use sterile, well-drained soil media.
• Space plants for good air circulation.
• Remove and destroy infected plants.
• Rotate with less susceptible crops such as alyssum, daffodil, salvia, pansy, or ornamental grasses for at least 3 years.

Thank you for your question and have a great gardening summer.