WSU Onion Field Day
Prime Conditions for Powdery Mildew Story and photos by Denise Keller, Editor
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oward the end of July this year, Washington State University (WSU) plant pathologist Lindsey du Toit began hearing from onion growers reporting powdery mildew in their Columbia Basin onion fields. By the time the annual WSU Onion Field Day rolled around on Aug. 28, powdery mildew incidence in the Columbia Basin was the highest du Toit has seen in her 25 years of working with onions in the region. At the field day, she took the opportunity to educate attendees about powdery mildew development, symptoms and management. WSU plant pathologist Lindsey du Toit points out symptoms of powdery mildew on an onion plant.
Field day attendees listen to presentations from researchers.
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Onion World • November 2025