Diseases

Crown Rot

Crown rot is a general term that is hard to describe. The list is up to at least four different diseases or possible causal agents. Look for an AHS Journal article and a summary here in the future.

Anthracnose

Hostas that are heat dormant or are stressed due to lack of water or to nutritional deficiencies in mid-summer may develop red spots. These are a secondary anthracnose infection and are more pronounced on gold hostas especially tokudama types but are present on green and blue hostas also. Again a systemic fungicide will help control the spread of the fungus but not make the spots go away. Good cultural practices, (regular irrigation, maintaining adequate nitrogen levels throughout the summer, and keeping the plants cool buy overhead watering or shading them), may decrease this pest problem.

Unlike Southern Blight, none of these fungus problems are persistent. Good fall garden cleanup of old foliage may reduce the number fungus spores in the area but the susceptibility of certain hostas (i.e., H. 'tokudama') to infection maybe genetically based.

** Please follow label directions and all state and federal regulations on pesticide use.


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