Informational table showing disease name, symptoms, pathogen/cause, and management of Echinacea diseases. Disease Symptoms Pathogen/Cause Management Alternaria leaf spot Small dark brown to black leaf spots become oblong and develop lighter-colored centers as they enlarge. Spots on young plants are often along the midrib. Alternaria Water in a manner that keeps moisture off the leaves and stems. Apply a fungicide to protect plants. Aster yellows Flowers remain green. Leaf-like structures form in place of some flower parts and tight clusters of such flowers may form. In the spring, foliage may be bright yellow. Aster yellows phytoplasma spread by leafhoppers Remove infected plants. Remove weeds in the area and other aster-related plants that have similar symptoms. Bacterial leaf spot Dark brown to black spots form on leaves and are angular in shape because they are limited by large leaf veins. The spots often have a yellow halo Pseudomonas cichorii Water in a manner that keeps moisture off the leaves and stems. Apply bactericide to protect healthy plants Botrytis leaf spot and stem rot Brown spotting on leaves is sometimes accompanied by a stem rot. Botrytis cinerea Water in a manner that keeps moisture off the leaves and stems.Apply a fungicide to protect plants. Cercospora leaf spot Brown spots from on the leaves. Tiny black dots are seen within the spots. Cercospora tabacina Water in a manner that keeps moisture off the leaves and stems. Apply a fungicide to protect plants. Foliar nematode Purplish, angular spots form between veins. The spots become tan with age. Aphelenchoides Most other perennials are also susceptible to foliar nematode. Examine all surrounding plants for similar symptoms. Remove infected plants. Water in a manner that keeps moisture off the leaves and stems. Leaf mottle Light and dark green blotches develop on leaves. Sometimes there dark green ring spots present or line patterns and etches formed by dead tissue. Impatiens necrotic spot virus (INSV), cucumber mosaic virus (CMV), and others Remove infected plants. Control thrips (that move INSV) and aphids (that move CMV). Sclerotinia and Sclerotium crown rot Plants with dark spots on lower stems and dark roots wilt and die. White fungus with dark granule-like (Sclerotinia) or tan balls (Sclerotium) structures form on the surface of the dead areas. Sclerotinia sclerotiorum and Sclerotium rolfsii Remove infected plants. Septoria leaf spot Purplish-brown spots develop on the leaves, often completely covering older leaves. Septoria lepachydis Water in a manner that keeps moisture off the leaves and stems. White smut Yellow spots form on the leaves and become brown with age. Entyloma compositarum Several plants in the aster family are susceptible and should be examined for symptoms. Apply a fungicide to protect plants.

Prepared by Gary W. Moorman, Plant Pathology Professor