Echinacea Diseases
Gary W. Moorman, Plant Pathology Professor
| 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 iprodione + thiophanate methyl or copper to protect healthy 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 copper 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 iprodione + thiophanate methyl or copper to protect healthy 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 iprodione + thiophanate methyl or copper to protect healthy 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 iprodione + thiophanate methyl to protect healthy plants. |
| FRAC Group No. | Risk Level | Class | Active ingredient | REI Restricted Entry Interval | Trade names (EPA Reg. no.) |
|---|---|---|---|---|---|
| M | 1 | Copper complex | copper sulfate | 24 | Phyton 27 (49538-3) |
| copper ammonium | Liqui-Cop (54705-7) | ||||
| copper salts | Camelot (67690-36) | ||||
| Copper , fixed | copper hydroxide | 24 | CuPRO 2005 (67690-37) | ||
| Champ (55146-64) | |||||
| Combined product | |||||
| 12 + 1 | 3 | iprodione + | 12 | 26/36 Fungicide (432-1414-1001) | |
| thiophanate methyl |
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