By Stephen Wegulo and Kyle Broderick
Wheat disease surveys were conducted May 12 to May 21 in the wheat-growing regions of Nebraska. Irrigated fields (Figure 1) looked healthy with normal growth and a lush green canopy. In dryland fields, the soil was very dry (Figure 2) and wheat was stunted, averaging a foot tall (Figure 3). Growth stage ranged from flag leaf emerged in the northern Panhandle to flowering or past flowering in the southeast.
In the southwest, leaf yellowing resembling barley yellow dwarf was observed in some fields (Figures 4 and 5), but it was determined that the yellowing was due to freeze injury that occurred in mid- and late April. In a previous CropWatch article, leaf yellowing in a field at the West Central Research, Extension and Education Center (WCREEC) near North Platte was attributed to barley yellow dwarf. However, a second visit to the same field determined that most of the yellowing was due to freeze injury.
An isolated case of severe wheat streak mosaic disease complex (Figure 6) was observed in a grower’s field in Colfax County. This field is adjacent to a field that had volunteer wheat that was not controlled before planting wheat last fall.
From May 18-21, leaf rust and stripe rust (Figure 7) and fungal leaf spot diseases (Figure 8) were observed in research plots at Havelock Research Farm in Lincoln, Lancaster County. Moderate to high levels of barley yellow dwarf were observed in scattered areas in research plots at Havelock Research Farm.
Source : unl.edu