Wheat (Triticum aestivum)-Pythium Root Rot

Latest revision: 
March 2024

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Cause Pythium spp. (syn. Globisporangium spp.) are fungus-like microorganisms that live for years in soil and on old root debris, parasitizing the roots of wheat and many other plant species. The disease can be important in all wheat-producing areas.

Symptoms Mild infections may reduce population and tillering, and delay maturation. Adult plants may be stunted and/or chlorotic, as if nitrogen deficient. Heads may contain shriveled grain. Symptoms are often uniform across the field and are difficult to recognize and diagnose. Severe infections cause a general root rot.

Cultural control

  • Plant when soil temperature (about 50°F) allows seeds to germinate and establish quickly.
  • Use high-quality seed and supplemental phosphorus.

Chemical control Seed treatment reduces seedling infection.

  • Acquire (Group 4) at 0.75 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
  • Allegiance-FL at 0.75 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
  • Apron XL at 0.32 to 0.64 fl oz/100 lb seed plus a dye. See label for reentry restrictions.