A survey of fields in south central, southeast, and northeast Nebraska shows wheat diseases increasing in severity and occurrence. Stripe rust and leaf rust have developed to severe levels in fields plant with susceptible varieties that weren't sprayed to protect the flag leaf.
In a survey of wheat fields and research plots in south central and southeast Nebraska on May 24-25, stripe rust was the predominant fungal disease found. Its increase is due to the rainfall and cool temperatures that have prevailed during the last two weeks.
Recent rainfall and cool temperatures have favored development of stripe rust to severe levels on flag leaves in fields that have not been sprayed as shown in Figure 1, a photo taken Wednesday, May 24, in a grower’s field in Webster County in south-central Nebraska.
A survey of wheat fields in the Nebraska Panhandle found only trace levels of stripe rust and low levels of tan spot, but widespread areas of wheat streak mosaic virus with severity ranging from mild to severe.
Research plots at UNL’s Agricultural Research and Development Center (ARDC) were surveyed for diseases on May 12. These plots are not sprayed with fungicide and therefore the diseases and disease levels in them can be representative of those in growers’ fields under similar conditions. Here's what we found.
Because of the presence of stripe rust and leaf rust in the state, as well as increasing incidence and severity of Septoria leaf blotch and tan spot, growers are encouraged to be vigilant in scouting their fields.
Wheat fields are still looking green (Figure 1). However, development of several diseases is increasing. On April 26, stripe rust was confirmed in Nuckolls County in south central Nebraska and on April 27, it was found at low to moderate levels in research plots at the University of Nebraska-Lincoln’s Havelock Research Farm near Lincoln in Lancaster County (Figure 2).