A fungal pathogen that can cause considerable damage in grain crops known as stripe rust has been confirmed in western Idaho, University of Idaho Extension confirmed on Wednesday.
The disease was detected on the soft white winter wheat variety UI Magic CL Plus.
Juliet Marshall, a UI Extension cereals pathologist, said winter wheat in that area has developed past the window in which fungicide application would be beneficial. Fall grain in western Idaho is now in the grain-fill stage, she said in an announcement to farmers.
The region’s spring wheat should still be scouted for stripe rust, and treated with a fungicide if need be, she said.
In the Magic Valley and Eastern Idaho, Marshall said winter wheat is still at the heading stage and may still be protected by spraying to potentially avoid significant yield loss associated with stripe rust infection.
“Please note that while some varieties were reported as resistant in 2019, race changes were reported in California by (University of California-Davis pathologist) Mark Lundy in this year’s crop,” Marshall said in her message to growers. “Therefore scouting of all varieties is recommended this season. Please report observations so we can keep track of the in-season spread.”
Marshall said the regional weather for the coming week forecast is conducive to stripe rust spread and infection. Stripe rust likes cool and moist conditions, and spores can travel long distances in the wind.