Monitoring and Managing Cucurbit Downy Mildew
Historically, Michigan growers produce over 342,000 tons of cucurbits valued at about $99 million on 49,000 acres. Michigan is the number 1 producer of pickling cucumbers and fresh market/processing squash, number 3 producer of fresh market cucumbers, and number 6 producer of pumpkins in the nation. Pseudoperonospora cubensis causes cucurbit downy mildew and infects these crops as well as watermelons, cantaloupes, zucchinis, gourds and honeydew melons. Downy mildew re-emerged as a problem on cucumbers in Michigan in August 2005 when the disease spread across the eastern region of the United States.
Recognizing Downy Mildew on Cucurbits:
- Yellowing on top surface of leaves bound by veins
- Velvety or fuzzy dark spore growth on the underside of leaves