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).
A good, thick stand of wheat, such as this one near McCook provides a warmer microclimate near the soil surface that reduces the potential for freeze injury. (Photos by Robert Klein)
Figure 1. Stripe rust was found this week in wheat fields in two Nebraska counties ― Sheridan and Box Butte ― and growers are urged to scout fields regularly.
Winter wheat growth in Nebraska is progressing at a steady pace, with most fields now green with little or on disease; however, growers are urged to continue scouting their wheat for early signs of disease as current and forecasted wet weather this spring is likely to lead to severe disease outbreaks.
Figure 1. A grower’s wheat field in Saline County on March 22. Winter wheat is greening up across Nebraska and growers are urged tos scout for disease, given the forecasts for a wet spring. (Photos by Stephen Wegulo)
The wheat-growing season is off to an early start due to a mild winter. Wheat fields are looking green from a distance (Figure 1), but closer examination reveals freeze damage in some fields caused by periods of subfreezing temperatures that occurred after growth had resumed (Figures 2 and 3).
Figure 1. Severe symptoms of wheat streak mosaic in volunteer wheat in sunflower stubble in Deuel County in November 2016. Such a field significantly increases the risk of infection of wheat in nearby fields. (Photo by Gary Hein)
While the mild fall promoted wheat establishment, it also favored survival of wheat curl mites, the leading vector of several viruses common to Nebraska wheat. While much of the state's wheat crop entered winter in very good condition, growers are urged to scout for viruses this spring and assess yield potential of individual fields when making management decisions.
