Stripe rust, also known as yellow rust, is caused by the fungus Puccinia striiformis and can affect wheat, barley and triticale. Stripe rust is identified by small, yellowish uredinia that appear in linear rows the length of the leaf blade (see figure).
In Manitoba, stripe rust does not overwinter. Instead, the majority of our stripe rust inoculum blows in from the central US states by what is known as the “Puccinia Pathway”. Normally the first inoculum starts arriving at the beginning of June. However, this can vary depending on how much inoculum is present in the United States and when the winds blow from the south.
Fortunately, the progress of stripe rust inoculum, as well as other cereal rusts, is documented on the USDA’s website (http://www.ars.usda.gov/News/docs.htm?docid=9757). To date, there have been a number of stripe rust detections in winter wheat, with the most recent located in North Dakota (in winter wheat research plots in two different counties – as reported by Andrew Friskop, Cereal Extension Pathologist with NDSU Department of Plant Pathology).
In Manitoba, majority of winter wheat is in the stem elongation stage of development. There have been no reports of stripe rust to date; however, inoculum can move quickly so growers should scout their winter wheat for early infections. The good news is stripe rust can be managed by timely fungicide applications. If the disease pressure, weather conditions (stripe rust favours cool, damp conditions) and crop yield potential warrant application, foliar fungicides should be applied before the disease is well-established in the crop to provide maximum benefit. There are numerous products available for the control of stripe rust; please refer to the Guide to Field Crop Protection.
For more information on stripe rust, its symptoms and control measures, visit Manitoba Agriculture’s website at http://www.gov.mb.ca/agriculture/crops/plant-diseases/stripe-rust-puccina-pathway.html.
Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture