Disease updates & alerts

As the season progresses, cereal diseases have been found in various regions of Alberta. Pathologists from Prairie Crop Disease Monitoring Network (PCDMN) have received observations of the common cereal diseases. Check out the disease alerts they sent, and add the disease to your scouting list if they are in your region :

1. Wheat streak Mosaic virus

Wheat streak mosaic virus (WSMV) has been confirmed in 5  fields in Southern Alberta. Producers, agronomists and crop scouts are encouraged to watch for symptoms of WSMV on wheat (winter, spring, durum), barley, corn and all other cereals and grasses.

When in doubt, reach out to Alberta Plant Health Lab planthealthlab@gov.ab.ca about having the sample tested.

2. Powdery Mildew

Powdery mildew symptoms were found in at least 5 fields in the Lacombe area, while more were observed in the Ponoka region. Agronomists are encouraged to scout into the mid canopy, where the microclimate may be more humid.

Management of powdery mildew is mainly achieved via the use of resistant varieties or fungicide application. Though varieties have different levels of resistance to powdery mildew, the disease resistance rating is not available on the Seed Guide. Fungicides can be very effective, especially when upper canopy leaves can be protected to ensure improved grain filling and yield.

3. Stripe Rust

Stripe rust symptoms have been observed in the following regions. Wheat producers in these regions should be on the look out for stripe rust development.

1. Calgary to Drumheller

2. Airdrie and Madden

3. Taber

4. Nanton and Claresholm

5. Penhold, Rimbey, Bentley, Sylvan Lake, and Ponoka

6. Bruderheim

Early detection is the key to managing stripe rust, especially for susceptible varieties. Refer to PCDMN’s stripe rust forecast for the general risk in your region. For susceptible varieties, a fungicide application is warranted when approximately one plant per square meter is rusted. Scouting for early detection is critical as once 5% of the flag leaf area becomes symptomatic in susceptible varieties it is very challenging to manage with a fungicide. A fungicide application may not be necessary for resistant varieties. Once any variety is past anthesis, a fungicide application is not likely to provide economic benefit.

Figure 6. Symptoms of stripe rust from early July 2025, Calgary to Drumheller region. Photographs courtesy of Micayla Code, Emma Nesbitt and Grace Gregory, Nutrien. 

Takeaways & action items 

As the crop goes into booting, flowering and grain filling stage, protecting the flag leaf (plus penultimate leaf in barley) and head from diseases is top of mind for a successful crop.

A few things you can do to help:

  • Subscribe to Prairie Crop Disease Monitoring Network to receive timely disease risk updates and disease alerts.
  • Use diagnostics resources such as :
    • Disease scouting cards by PCDMN.
    • Diagnostic labs such as Alberta Plant Health Lab, Innotech Alberta.
  • Have the sprayer calibrate and ready, in case a fungicide application is called for.
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