A water-soaked region on infected seedlings or plants may extend several inches above the soil line with little, if any, visible evidence of the fungus. Pythium root rot. Disease Management Soil-borne pathogens of dry beans and other Crops can be managed to reduce but not eliminate damage. Integrated and carefully implemented approaches to crop production reduce disease pressure and plant stress. This enables vigorous plants to more successfully obtain nutrients and moisture during critical vegetative and reproductive periods.
Crop rotation reduces residual populations of all four root rot organisms.
A three-year crop rotation with beans planted every third or, ideally, fourth or fifth year is best. Potatoes and sugar beets may increase fungus inoculum in the soil and should not be included in the rotation if a field has a history of Rhizoctonia root rot. Resistant Crops include alfalfa, barley, wheat, oats and corn. Previous crop stubble always should be well incorporated into the soil and decomposed before bean planting. This avoids temporary nitrogen deficiency, hence plant stress, early in the season.