As of June 24, 2019, wind trajectory reports show that the risk for cereal rust remains low in the Prairie region, according to latest report from the Prairie Crop Disease Monitoring Network (PCDMN).
Currently, the PCDMN have not heard any reports of stripe or leaf rust in commercial fields of winter or spring wheat across the Prairie region.
Wind trajectory models are used as an “early-warning system” for pests and diseases. Rust spores usually travel with the wind from the U.S. into Canada. The rust situation in the U.S. is a good indicator of disease pressure in Canada. Below is a synopsis of the weekly cereal rust risk report for the week of June 24, 2019, showing that risk is low and scouting for rust is not urgent unless producers had noticed stripe rust development on winter wheat in the fall of 2018.
Pacific Northwest (PNW)
Although there has been a moderate number of recent wind trajectories from the PNW, there is limited stripe rust development in the PNW to begin with. As of June 24, the risk of stripe rust appearing from the PNW is relatively low and scouting for the disease is not urgent.
Rainfall occurred in the Saskatchewan 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.
In general, crops are advancing towards maturity. In many areas of Texas and Oklahoma, crops have been harvested or are being harvested, and therefore 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 Saskatchewan 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. According to the PCDMN, 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.
Kansas crops are starting to mature with harvest starting in some regions. In Nebraska, leaf and stripe rust development continues, and therefore 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 was a low-moderate number of wind trajectories from this area, according to the PCDMN. 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. The PCDMN noted that rust symptoms have been observed in research plots in St. Paul, MN. Stripe and leaf rust have also been observed in research plots at the South Dakota State University Research Farm, but no rust was observed in commercial fields in southeastern and south central regions of South Dakota.
Agriculture and Agri-Food Canada and Environment and Climate Change Canada have been working together to study the potential trajectories for monitoring insect movements since the late 1990s. The full wind trajectories report, with weather and overwintering analysis, is available on the Prairie Pest Monitoring Network blog.