Yellow to pale-green lesions caused by downy mildew on scapes in an onion seed crop. Note the ‘dirty gray’ appearance in the center of two of the lesions as a result of sporulation of <em>Peronospora destructor</em>.

Yellow to pale-green lesions caused by downy mildew on scapes in an onion seed crop. Note the ‘dirty gray’ appearance in the center of two of the lesions as a result of sporulation of Peronospora destructor.

Photo Source: Lindsey du Toit, Washington State University