In 2019, the PCDMN will release a series of weekly Cereal Rust Risk Reports throughout May and June. Information related to trajectory events based on forecast and diagnostic wind fields and cereal rust risk is experimental, and is OFFERED TO THE PUBLIC FOR INFORMATIONAL PURPOSES ONLY.
Background: Agriculture and AgriFood Canada (AAFC) and Environment and Climate Change Canada (ECCC) have been working together to study the potential of trajectories for monitoring insect movements since the late 1990s. Trajectory models are used to deliver an early-warning system for the origin and destination of migratory invasive species, such as diamondback moth. In addition, plant pathologists have shown that trajectories can assist with the prediction of plant disease infestations and are also beginning to utilize these same data. An introduction will be presented of efforts to identify wind trajectory events that may bring rust urediniospores into Western Canada from epidemic areas in the central and Pacific northwest (PNW) regions of the USA. Identification of potential events as well as an assessment of epidemic severity from source locations, and prairie weather conditions, will be used to assess the need for prompt targeted crop scouting for at-risk regions of the Canadian Prairies.
Two documents are available from the PCDMN:
• An introduction to cereal rust risk and wind trajectories from the USA.
• WIND TRAJECTORY AND CEREAL RUST RISK REPORT for June 24, 2019
Summary of wind trajectory and cereal rust risk assessment and the need for in-crop scouting in the Prairie region, June 18-24, 2019:
1. Pacific Northwest – Currently there is limited stripe rust development in the PNW, although there has been a moderate number of recent wind trajectories from the PNW. Rainfall did occur in SK and some regions of Alberta. Winter wheat is progressing into heading and beyond, and spring wheat is moving from the stem elongation stage to flag leaf emergence. Thus, as of June 24, 2019, the risk of stripe rust appearance from the PNW is relatively low and scouting for this disease is not urgent.
2. Texas-Oklahoma corridor – In general, crops are advancing towards maturity, while in many areas of Texas and Oklahoma crops have been harvested or are being harvested, and thus winter wheat crops in these areas are less of a source of rust inoculum. There were no recent wind trajectories from this area, while rainfall did occur in SK and some regions of Alberta. Winter wheat is progressing into heading and beyond, and spring wheat is moving from the stem elongation stage to flag leaf emergence. Thus, as of June 24, 2019, the risk of leaf and stripe rust appearance from the Texas-Oklahoma corridor is low and scouting for these diseases is not urgent.
3. Kansas-Nebraska corridor – Kansas crops are starting to mature with harvesting starting in some regions. In Nebraska, leaf and stripe rust development continues, and thus over the next few weeks this region could act as a significant source of rust inoculum for the Prairie region. From June 18-24, 2019 there has been a low-moderate number of wind trajectories from this area. Rainfall did occur in SK and some regions of Alberta, while winter wheat is progressing into heading and beyond, and spring wheat is moving from the stem elongation stage to flag leaf emergence. Thus, as of June 24, 2019, the risk of leaf and stripe rust appearance from the Kansas-Nebraska corridor is relatively low and scouting for these diseases is not urgent. Although further development of rust in Nebraska may increase the risk, the crop will soon start to progress towards maturity and will become less of a source of the cereal rusts. It should be noted that rust symptoms have been observed in research plots in St. Paul, MN (Cereal Rust Survey, CEREAL-RUST-SURVEY@LISTS.UMN.EDU, Dr. O. Fajolu, USDA-ARS Cereal Disease Lab, June 18, 2019). Stripe and leaf rust have also been observed in research plots at the South Dakota State University Research Farm, while no rust was observed in commercial fields in southeastern and southcentral regions of the SD (Cereal Rust Survey, CEREAL-RUST-SURVEY@LISTS.UMN.EDU, Dr. E. Byamukama, South Dakota State University, June 18, 2019).
4. Currently, we are not aware of reports of stripe or leaf rust in commercial fields of winter or spring wheat across the Prairie region.