Fusarium Head Blight Showing Up in Isolated Wheat Fields - UNL CropWatch, June 10, 2011

Fusarium Head Blight Showing Up in Isolated Wheat Fields - UNL CropWatch, June 10, 2011

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Figure 1. A wheat head affected by scab in research plots in Saunders County on June 9. Figure 2. Scab in a center pivot corner planted with wheat next to corn stubble in Keith County on June 9.

June 10, 2011

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On June 9, Fusarium head blight (scab, Figure 1) was found in research plots at Mead, Saunders County, in southeast Nebraska. Incidence was low (about 5%), with severity ranging from trace to entire heads bleached. Farther west in Keith County, scab was found in a couple of isolated commercial fields with incidence of up to 40% and severity of mostly 100% on affected heads. One of the fields has corn stubble on the ground surface. Fields just a couple of miles away where corn stubble was worked into the top two inches of the soil had no scab. The other field (Figure 2) is a center pivot corner planted with wheat next to corn stubble. There was a clear gradient of scab incidence in this field, with the highest incidence next to the corn stubble and the lowest incidence farthest away from the corn stubble (Figure 3).

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Figure 3. A section of the center pivot corner shown to in Figure 2 showing a higher incidence of scab next to the corn stubble (front of photo) and a much lower incidence of scab farthest from the corn stubble.

On June 2 scab was observed at low levels in a commercial field in Chase County. On June 3, scab was observed in early stages of development in a breeder nursery in Lancaster County and in a commercial wheat field in Webster County.

What To Do If You See Scab in Your Field

Once scab appears in a wheat field, it is too late to spray a fungicide to suppress it. At this time scab is still developing in affected fields. So far it has been observed only in isolated fields. Keep an eye on your field to determine the extent to which it is affected by scab. Some areas of the field may be affected more than others. If some parts of the field become severely affected, plan to harvest those areas separately from the rest of the field. When harvesting fields affected by scab, increase the fan speed on the combine to blow out scabby grain.

Stephen Wegulo
Extension Plant Pathologist, Lincoln