Time is ripe for powdery mildew

WOOSTER, Ohio – With Ohio’s wheat crop under way and performing well despite frost damage concerns, now is the time for growers to begin scouting for foliar diseases, especially on susceptible varieties.
Powdery mildew. Pierce Paul, an Ohio State University plant pathologist with the Ohio Agricultural Research and Development Center, said growers should be on the lookout for powdery mildew.
Powdery mildew is one of the most common wheat diseases in Ohio. Mild temperatures, high relative humidity and dense stands favor mildew development.
It is most prevalent on the lower leaves of susceptible varieties when wheat is in the joint to flag-leaf stage of development. This disease results in reduced kernel size and test weight, and ultimately lower yields.
“Growers should get out in their fields and pull a few plants. Look for whitish fungal growth on the lower leaves,” said Paul, who also holds a partial Ohio State University Extension appointment.
“As the crop progresses toward boot stage and if growers see lesions spreading up the plant, then it may be time to apply fungicides.”
Fungicides. There are several fungicides available to Ohio growers that control powdery mildew. They include Headline, PropiMax, Quilt, Stratego and Tilt.
As the season progresses, Paul said growers should be on the lookout for Stagonospora leaf/glume blotch and leaf rust. A new fungicide, Proline, is available to growers this season and effectively controls both diseases, as do the other fungicides. Proline is still being tested for its effectiveness against powdery mildew.
“As with any fungicide use, growers should scout their fields first and then apply fungicides only when it’s warranted,” said Paul.
“Keeping the flag leaf healthy is important. It contributes most of the sugars for grain development.”