Stripe rust was found on winter wheat in several South Dakota locations the week of May 21.

The USDA Cereal Disease Lab reports that stripe rust appeared at nearly the same time in Minnesota, North Dakota, Wisconsin, and Ontario, Canada, suggesting that there were likely one or more recent very large spore shower events. If cool, wet conditions persist, stripe rust can be expected to spread aggressively, whereas warm temperatures and dry conditions will cause it to shut down, says Bob Fanning, SDSU Extension Plant Pathology Field Specialist.

"Leaf rust has been reported in southern Nebraska, but to date, no farther north. With winter wheat rapidly progressing, much of it flowering or nearly flowering, producers will need to make fungicide decisions soon if they haven't already," Fanning said.

Fanning reminds growers to read and follow label directions and adhere to harvest intervals.

"Foliar fungicide application decisions at this stage should be based on yield potential, progression of residue borne diseases from the lower leaves, weather forecasts and risk of head scab and rust diseases," Fanning said.

View the Resource Library and links section of iGrow Wheat (http://igrow.org/agronomy/wheat/) for the following resources:

  • USDA Cereal Disease Laboratory - Progression of leaf, stripe and other rust situations moving up from the South can be monitored
  • Use the "Risk Map Tool" on the "Wheat Fusarium Head Blight Prediction Center" website to monitor head scab risk
  • For information on fungicide recommendations, access SDSU Extension publications "South Dakota Wheat Fungicide Recommendations" and "Managing Crop Diseases with Fungicides." Additional information regarding resistance and variety performance can be found in 2011 Winter Wheat Variety Yield Results and 2012 Spring Wheat Variety Recommendations and 2011 Variety Performance Results. 

If you have additional questions about stripe rust or other plant diseases, contact your local SDSU Extension Plant Pathology Field Specialist by contacting your SDSU Extension Regional Center, contact information available at iGrow.org.