The latest Prairie PCDMN wind trajectory cereal rust risk report is available for download now at the following link: July 5-11, 2022 report.
As of the week of July 11, 2022 the overall Prairie cereal rust risk assessments and need for in-crop scouting are as follows:
Pacific Northwest – There was a moderate number of wind trajectories that passed over the PNW region from July 5-11, 2022 and into the prairies, while key stages of crop development are occurring for spring wheat. Winter wheat is well into grain filling and moving towards maturing, and thus the potential impact of stripe rust arrival is reduced compared to earlier growth stages. In terms of stripe rust development in the PNW there have been increasing reports of occurrence including in commercial fields up until June 17, 2022. However, Dr. Chen has issued his last report for 2022 on July 14, 2022 and indicated the “stripe rust season” is finished for winter wheat and is close to being complete for spring cereals (https://striperust.wsu.edu/2022/07/14/stripe-rust-update-july-14-2022/).
Some Prairie regions where most trajectories ended, did receive more moisture from July 5-11, 2022. Thus, as of July 11, 2022, the risk of stripe rust appearance from the PNW is low to moderate, while scouting for this disease in the Prairie region should be considered for those locations that received increased trajectories and moisture, especially where stripe rust susceptible varieties are planted. Overall, the PNW winter wheat crop is rapidly maturing with 2% of the crop harvested as of July 10, 2022 (https://quickstats.nass.usda.gov/results/BDEFEE07-E8FB-3C93-9D73-E7FE398F98B4).
Thus, as of July 14, 2022 the PNW is of limited risk in terms of acting as a source of rust inoculum for the Prairie region. Given the stage of crop development in the PNW this is the last Prairie cereal rust risk report for 2022.
Kansas-Nebraska corridor – Currently, there is limited leaf and stripe rust development in this corridor and a relatively low number of recent wind trajectories from this area, even though rainfall was increased in some areas of the eastern Prairie region. Most crops in this region are mature and have or will be harvested. Given these factors, as of July 11, 2022, the risk of leaf and stripe rust appearance from the Kansas-Nebraska corridor is generally limited and scouting for these diseases in the Prairies is not urgent.
Prairie regions and the Northern Great Plains – There have been two reports of stripe rust in disease screening plots in the Lethbridge, AB and Saskatoon, SK regions, while stripe rust was recently observed on tame and wild grass species in the Peace region. Given these observations and recent observations of stripe and leaf rust in North Dakota, growers with highly rust susceptible fields may want to keep an eye out for stripe and leaf rust in later developing spring wheat fields.
