2011 Winter Wheat Survey for Diseases and Insects - UNL CropWatch, June 10, 2011

2011 Winter Wheat Survey for Diseases and Insects - UNL CropWatch, June 10, 2011

barley yellow dwarf wheat damage Wheat damage
Figure 1. Barley yellow dwarf in Polk County on May 30. Figure 2. Russian wheat aphid damage in Cheyenne County June 1. Figure 3. Stem maggot damage in Chase County on June 2.

June 10, 2011

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 Figure 4. A section of a field with 100% incidence of wheat streak mosaic in Cheyenne County on June 1.

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Figure 5. Powdery mildew in Webster County on June 3.

The 2011 winter wheat survey was conducted in the wheat growing areas of Nebraska from May 30 to June 3 by a group of UNL Extension specialists and educators.

Barley yellow dwarf (Figure 1) was widespread throughout the state with varying levels of incidence. Lady beetles were observed in many fields, indicating an increased presence of cereal aphids, which carry and transmit barley yellow dwarf virus. Damage from the Russian wheat aphid (Figure 2) and stem maggot (Figure 3) was seen but at quite low (non-economic) levels. Additionally, other grain aphids (for example, English grain aphids and greenbugs) were present in low populations as were some adult sawflies throughout the Panhandle (about 1-2 per 50 sweeps in about 75% of visited fields).

Some areas in the Panhandle and southwest Nebraska were severely impacted by wheat streak mosaic virus (Figure 4). The wheat streak severity in these areas could be mostly traced back to inadequately controlled volunteer wheat in areas that had preharvest hail in 2010.

Other diseases observed were powdery mildew (Figure 5), tan spot (Figure 6), Septoria tritici blotch, loose smut (Figure 8), stripe rust (Figure 9), leaf rust (Figure 10), and Fusarium head blight (scab) in its early stages of development on barley (Figure 10) and wheat (Figure 11).  (See related story).

In general, the development of the wheat crop was slightly behind due to prolonged cool weather in the spring. Some fields had an uneven stand due to uneven emergence resulting from a lack of adequate moisture in fall 2010.

Stephen Wegulo, Extension Plant Pathologist, Lincoln
Gary Hein, Entomologist, Lincoln
Drew Lyon, Extension Dryland Crops Specialist, Scottsbluff
Robert Harveson, Extension Plant Pathologist, Scottsbluff
Jeff Bradshaw, Extension Entomologist, Scottsbluff
William Booker, Extension Educator, Box Butte County
Dewey Lienemann, Extension Educator, Webster County
Emmanuel Byamukama, Post-doctoral Research Associate, Lincoln

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 Figure 6. Tan spot in Box Butte County on May 31.  Figure 7. Septoria tritici blotch and loose smut in Chase County on June 2.  Figure 8. Severe stripe rust in Webster County on June 3.
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Figure 9. Leaf rust in a breeder nursery in Lancaster County on June 3. Figure 10. Fusarium head blight on barley in a breeder nursery in Lancaster County on June 3. Figure 11. Fusarium head blight on wheat in Webster County on June 3.