By Stephen Wegulo
Extension Plant Pathologist
Figure 1. Fusarium head blight in a grower's field in Chase County on June 23.
A survey of wheat fields June 22-24 showed moderate to severe Fusarium head blight (scab) in southeast, south central, and southwest Nebraska (Figure 1). Trace levels of the disease were observed in Kimball, Cheyenne, and Box Butte counties in the Panhandle.
Figure 2. (L) Stripe rust on a wheat plant stunted by wheat streak mosaic in Kimball County on June 23. Figure 3. (R) Leaf rust on a susceptible wheat line in a state variety trial in Hichcock County on June 23.
Stripe rust development had ceased in most parts of the state. Some plants with actively sporulating pustules were observed in the southern and northern Panhandle (Figure 2).
Leaf rust development had picked up and was severe in some lines in a state variety trial in Hitchcock County (Figure 3).
In the southern Panhandle, a few fields with severe wheat streak mosaic virus were observed. In one of these fields, damage from both wheat streak mosaic and stripe rust was evident (Figures 2 and 4).
Wheat in some fields had turned or was starting to turn color.
Figure 4. A section of a wheat field affected by wheat streak mosaic and stripe rust in Kimball County on June 23.
Management
It is too late this growing season to control wheat diseases. Rust and other foliar fungal diseases can be managed by scouting and fungicide application timed to protect the flag leaf. Wheat streak mosaic can be managed by controlling volunteer wheat and grassy weeds before planting in the fall.