Crown rot, or southern blight, was once just a disease of southern climates but has been seen recently in Minnesota, Illinois, Iowa and Michigan. |
Symptoms: Symptoms on hosta include wilting and yellowing lower leaves and stems dying at the soil line. A key diagnostic feature is the sclerotia (overwintering structure) of the fungus, which look like small tan mustard seeds. They can be found on infected parts of the plant as well as the surrounding soil. |
| Causal organism: | Sclerotium rolfsii |
| Over wintering: | In plant material and soil. |
| Months of infection: | Growing season |
| Method of dispersal: | Purchase of infected plants, transplanting of infected plants, spread of infected soil on shoes or tools. Also, the fungal mycelium can grow through the soil. |
| Infection point: | Stems and crown. |
| Control: | Purchase disease-free plants. Remove disease infected plants. Clean soil from tools and shoes. Quarantine any infected area of garden. |
| Labeled fungicides | PCNB (sold as Terraclor) or Flutolanil (sold as Contrast) Note: Not readily available to homeowners. |
| Comments: | Prevention is the best management strategy for this disease. Inspect all new plants carefully for signs or symptoms. |
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