Stay on top of cereal diseases

A good portion of the agricultural area in the province has received abundant rain throughout the month of June. Although it improves soil moisture, rain and high humidity favour crop diseases. In cereal crops, foliar diseases impact yield by reducing photosynthesis on flag or penultimate leaves; head diseases impact grain yield and/or quality. Amid the moisture and potential disease pressure, scouting to stay on top of the diseases is the starting point of protecting your crops against them.  

Many foliar diseases are favoured by high humidity and/or rain. In a year with above-average rainfall, the disease pressure can increase. Many of the foliar diseases start from the lower canopy, as they are closer to the inoculum (stubbles) and have a more humid microclimate. With high humidity, rain splash and mild temperature, the diseases may spread from lower to upper canopy and threaten the yield-crucial leaves.  

Add the following diseases to your scouting list and keep track of their development. Be ready to apply foliar fungicides to control fungal foliar diseases when the disease threatens the flag leaf (wheat) or penultimate leaf (barley). 

Wheat foliar diseases 

Barley-specific foliar diseases

Head diseases

If wet, humid weather is still prevalent during heading and flowering, cereal head diseases may become a risk. Keep the following diseases on your scouting list.  

To monitor the risk of an FHB outbreak, use a weather-based disease risk forecast tool such as the Prairie-wide Fusarium head blight risk mapping tool. Be ready to apply fungicides for FHB suppression if the risk is high. Besides weather conditions, the decision to spray may also depend on the level of resistance in the variety. 

Takeaways

  • Many foliar and head diseases are favoured by rain, high humidity and mild temperatures. In a wetter year, it is especially important to actively scout for diseases and be proactive.
  • Fungicides are preventative. They are most effective when applied before a large-scale infection has occurred.
  • Use the tools such as Cereal Rust Risk report and FHB Risk Mapping Tool along with scouting to estimate the field-specific risks.

Additional resources

Decision processes for barley fungicide application – Top Crop Manager 

Disease Scouting Playing Cards – Prairie Crop Disease Monitoring Network 

Septoria Leaf And Glume Blotch In Wheat, Barley, And Oats – Government of Manitoba 

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