Dry rot canker (DRC) is a root rot disease of sugarbeets that occurs infrequently throughout the irrigated western United States.
It was first reported by B. L. Richards in Utah in 1921, and has since been identified from California, Colorado, Minnesota, Montana, Nebraska, North Dakota and Wyoming. The disease is caused by a largely uncharacterized strain of Rhizoctonia and typified by localized, dry sunken lesions that penetrate into taproots forming internal cavities filled with brown spongy necrotic material. The surface tissues of the cankers also produce a distinctive series of concentric circles, like a target board, which is easily contrasted with the typical brown to black lesions associated with the more familiar Rhizoctonia root and crown rot (RRCR).
These symptom differences are also corroborated with genetic analyses. Complex molecular tests have convincingly proven that the DRC isolates are genetically distinct from the typical Rhizoctonia pathogen associated with RRCR. Since 2011, we have noted an increase in the dry rot canker disease incidence and it has been identified from more than one dozen fields in Morrill and Scotts Bluff counties in Nebraska in three of the last six years.
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