Update on Rust Diseases of Wheat – June 16, 2023
During wheat disease surveys June 12-15, stripe rust (Figure 1) was found to be widespread in the wheat growing regions of Nebraska, but only at trace levels. Counties in which stripe rust was found are Banner, Box Butte, Chase, Cheyenne, Deuel, Jefferson, Keith, Lincoln, Perkins and Red Willow. Leaf rust (Figure 2) was found in Jefferson County. Figure 3 and Figure 4 show the current distribution of stripe rust and leaf rust in Nebraska based on observations in the field or confirmation on samples submitted to the Plant and Pest Diagnostic Clinic.
Stripe rust and leaf rust have arrived in Nebraska late in the wheat growing season. They are not expected to cause significant yield reductions. Wheat in the majority of fields is past the growth stage (flowering) when a fungicide can be applied. Both stripe rust and leaf rust are at trace to low levels in the fields in which they have been observed. Warmer temperatures in the coming weeks will slow down stripe rust development. For these reasons, it is not recommended to spray a fungicide to control stripe rust or leaf rust. In the Panhandle, if wheat is irrigated, the variety planted is susceptible to stripe rust, the growth stage is at or before flowering, and stripe rust is observed, a fungicide application may be beneficial.