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Rhizoctonia root rot

© Iowa State University

Pathogen(s) causing disease:

Rhizoctonia solani


Produces a sunken, reddish-brown to dark brown decay of the outer layer of the main root and stem at the soil line and below. In contrast with Pythium root rot, Rhizoctonia-infected stems remain firm and dry. Phytophthora-infected roots are a dull, dark brown; those infected with Rhizoctonia are usually reddish brown.


Rainfall followed by cool and then warm, humid weather is most favorable for disease development. Growth of the Rhizoctonia fungus in soil depends on nutrient supply; soil moisture, temperature and pH; and competition from other soil microorganisms. Stress conditions - soil compaction, planting too deep, chemical damage.


Use a fungicide seed treatment. Promote good soil conditions that favor rapid seedling development. Avoid herbicide or other chemical damage. Avoid planting too deeply and compacting soil.


U of IL

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