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Powdery Mildew in Wheat


Today while checking some wheat fields, I noticed some powdery mildew in the lower canopy.  This disease isn’t particularly a problem for us but under the right conditions, can warrant treatment.  We will keep an eye on this as the season progresses to ensure it doesn’t work its way to within a leaf or two of the flag leaf.  Many years this is not a major concern but we should be aware of its presence so we don’t confuse it with wheat rust.

Dr. Alfredo Martinez, UGA Plant Pathologist, has this to say about powdery mildew on wheat;

“Powdery mildew is usually the first leaf disease to appear in the spring because the disease is favored by temperatures between 50 degrees and 70 degrees F (10 degrees C and 21 degrees C). The disease usually declines after flowering, when temperatures rise above 75 degrees F (24 degrees C). Powdery mildew can infect plants in the fall and survive in the invaded tissue during the winter. Early infection can result in reduced tillering of susceptible varieties. Thus, spores may come from earlier infections within the field or from fields farther away. Dense stands, high nitrogen fertility, and rapid plant growth increase susceptibility. Under such conditions a variety listed as having “good” resistance may become heavily infected. As the stem elongates and temperatures increase, conditions become less favorable for powdery mildew.”

The following chart will give you an idea as to the susceptibility of the variety of wheat that you have planted to powdery mildew and other diseases.

2015 wheat characteristics

If you have questions concerning this information, contact your local county extension office.