Such fungi infect by means of swimming spores called zoospores. Aphanomyces Root Rot of Sugarbeet. Aphanomyces is favored by warm and wet soils. This disease can be devastating in the seedling stage, but also can cause serious root rot later in the season.
Infected plants turn a sickly yellow green and tend to wilt in the afternoons of hot and sunny days.
Some plants may die, but those that survive have stunted roots and are unproductive. Tolerant varieties are not as severely affected as susceptible varieties, but still may sustain serious damage. Tachigaren seed pelleting provides protection against infection only for the first 4 weeks. Once a field dries enough for cultivation, this may be used to help dry and aerate the soil. It will not stop established infections but may help reduce new infections.