Pythium root rot

(Pythium)

Browning root rot or Pythium root rot is predominantly a seedling disease, causing reduced stands, delayed maturity and yield reductions. Pythium is most frequent where soil oxygen levels are low due to high rainfall. In western Canada, disease develops in wet soils low in phosphorus and organic matter. Spores of Pythium survive for many years in soil and crop residue. Worst outbreaks with heaviest damage occur when a dry spell is followed by abundant rain.

Scouting

Damping off occurs frequently when germination takes place under wet conditions. Seedlings that emerge usually recover but may experience impaired root development and delayed maturity. Look for disease symptoms in patches throughout fields, especially waterlogged areas. Infected plants become chlorotic and lower leaves turn yellow, then brown. Underground, look for dead root tips on small plants and brown lesions on roots of larger plants, particularly at tips of young roots.

Barley is more sensitive than wheat.

Control

Ensure good drainage and modify soil profile to improve aeration. High quality treated seed improves germination and vigour, helping to outgrow infections. Raxil T and Vitaflo 280 protect against Pythium root rot.