Above ground symptoms include preemergence damping off, poor seedling vigor, stunting, reduced tillering and delayed maturity.
Diseased roots have soft brown lesions.
Small young roots are attacked more frequently than large older roots. Pythium root rot is favored by cool wet soils. Pythium root rot is difficult to control because the pathogen is found in all agricultural soils. Planting high quality seed in a well drained seedbed is beneficial in establishing a good stand. High levels of phosphorous has been shown to reduce the severity of root rot.