In early winter of each year, Dr. Xianming Chen, USDA-ARS, and WSU, Pullman, WA, issues one or more stripe rust forecasts for the PNW region in the USA. Unfortunately, winter wheat crops in the PNW region serve as an important source of stripe rust inoculum for Prairie producers. These PNW forecasts from Dr. Chen serve as a heads-up for Prairie cereal producers regarding potential issues with stripe rust in the coming growing season.
Dr. Chen evaluates weather data (mainly temperatures) for November and December of each year as it impacts potential overwintering and subsequent development of stripe rust on PNW winter wheat crops. In his January 7, 2025 risk update, Dr. Chen indicates that 2025 is forecast to potentially have severe levels of stripe rust, with 27-57% yield losses in highly susceptible varieties. Overall, potential losses in commercial fields of winter wheat will vary based on the susceptibility level of the variety being grown, with yield losses in the 0-29% range. Moreover, growers considering spring wheat in the PNW are encouraged to avoid planting 2025 fields with moderately susceptible to susceptible stripe rust ratings. For Prairie wheat growers the development of stripe rust in the PNW can represent an important source of disease for the Prairie provinces.
The Prairie Crop Disease Network (PCDMN) is currently preparing for the 2025 growing season and will launch weekly cereal rust risk forecasts starting in mid May 2025. With the help of Environment Canada, we look at reverse wind trajectory occurrence and frequency for Prairie sites for the PNW, and the Texas/Oklahoma, Kansas/Nebraska regions. These trajectories can readily move cereal stripe, leaf, stem and crown rust uredospores from source locations in the USA into the Prairie region. Typically trajectories from the PNW are of most concern for central to western Prairie cereal growers, while trajectories from the Texas to Nebraska corridor are of most concern for central to eastern Prairie growers.
In addition to the occurrence of wind trajectories, the PCDMN also looks at the status of cereal rust development for source locations in the USA, as well as Prairie weather conditions and crop growth stages. Based on this information the PCDMN issues weekly updates for Prairie regions regarding potential risks and the need for targeted in-crop scouting.
Unfortunately, damaging cereal rust levels can develop quickly and without timely scouting and fungicide application, the efficacy of control can be significantly reduced. The PCDMN cereal rust forecasts help to identify Prairie regions with an elevated rust risk, thus allowing growers to make timely fungicide use decisions.
The PCDMN cereal rust forecasts appear on the in-season updates section of our website, where one can can also review past in-season updates for a range of crops and disease issues. The in-season updates provide a summary of the weekly rust forecasts, while the Cereal Rust Risk section provides the full weekly reports from current and past growing seasons.
As the 2025 growing season approaches, the PCDMN will be monitoring further rust risk forecasts from Dr. Chen as well as the status of rust development in source USA locations. Further updates will be provided with weekly cereal rust risk forecasts starting around mid-May. Stay tuned and monitor our PCDMN website and X (Twitter) feed for further information.

Stripe rust of wheat ® PCDMN.

Stripe rust of wheat ® PCDMN.

Stripe rust of wheat ® PCDMN.

Stripe rust of wheat ® PCDMN.

Leaf rust of wheat ® PCDMN.

Leaf rust of wheat ® PCDMN.

Leaf rust of wheat ® PCDMN.

Stem rust of wheat ® PCDMN.

Stem rust of wheat ® PCDMN.

Stem rust of wheat ® PCDMN.

Stem rust of wheat ® PCDMN.

Crown rust of oat ® PCDMN.

Crown rust of oat ® PCDMN.

Crown rust of oat ® PCDMN.

Crown rust of oat ® PCDMN.