WHEAT DISEASE UPDATE
I have looked at numerous wheat fields in the past week. They were remarkably clean of disease but we are experiencing ideal conditions for disease considering the rain and warm temperatures in March. Most of our wheat growers have yield goals of 75+ bushels per acre and protecting the flag leaf and head from disease with a fungicide application is an important practice in obtaining these high yields. Below is a foliar wheat disease update from Dr. Alfredo Martinez, University of Georgia Extension pathologist.
Foliar Wheat Disease Update
1. Powdery mildew. Moderate to heavy powdery mildew (Erysiphe graminis) infections have registered throughout the state. Powdery mildew tends to diminish as temperatures consistently reach above 75ºF and RH falls below 85%. However, if powdery mildew is continuing to progress up the plant and is found in upper leaves (flag leaf minus 2) you may consider a fungicide application.
For powdery mildew, fungicides options include: propiconazole (Tilt, Propimax); metconazole (Caramba); pyraclostrobin (Headline); azoxystrobin (Quadris); prothioconazole (Proline); propiconazole + trifloxystrobin (Stratego); propiconazole + azoxystrobin (Quilt, QuiltXcel), prothioconazole + tebuconazole (Prosaro); prothioconazole + trifloxystrobin (Stratego YLD); pyraclostrobin + metconazole (Twinline); tebuconazole + trifloxystrobin (Absolute).
Folicur (tebuconazole) is not labeled for powdery mildew.
A complete list of wheat fungicides, rates and specific remarks and precautions can be found at the 2012 Plant Management Handbook page 145 and/or at 2011-2012 Wheat Production Guide WheatProductionGuideComplete_000 (page 58). Always read the label for fungicide applications instructions, restrictions and proper handling.
2. Leaf Rust. No infections of leaf rust have been observed or reported in commercial fields. However, while Powdery mildew tends to diminish with warmer temperatures, leaf rust (Puccinia triticina-formerly P. recondita) and/or Stagonospora (leaf-glume blotch) (formerly Septoria) infections can surface with these present weather conditions in Georgia. Field monitoring for these diseases is advised.
3. Remember that for an appropriate filling of grain, protection of the flag leaf is essential.
For more information on wheat diseases http://plantpath.caes.uga.edu/extension/DiseaseLibrary.html#field