Components of a good PM management program:
1. Choose PM-tolerant or -resistant hybrids whenever possible to maximize host plant resistance against this disease.
2. Scout for PM beginning mid-summer on the upper and lower leaf surfaces throughout the field and leaf canopy. If even a few colonies are found, treatment should begin immediately and continue until harvest.
3. Know the Fungicide Resistance Action Code (FRAC) or mode of action (MOA) number (found on the label) for each fungicide used on your farm and how to rotate it.
Ohio State University Extension
Powdery mildew management | VGNews
Plant Pathologists at Land Grant Universities conduct fungicide efficacy trials on cucurbits to determine spray programs to recommend. Results of these trials are published in Plant Disease Management Reports.
Downy Mildew on Pumpkins in Ohio
Clade 1 of the downy mildew pathogen has a broad host range among cucurbits, preferring pumpkins, squash and watermelons. Clade 2 isolates infect and cause damage to cucumbers and melons, and are seen in northern Ohio first. As in 2022, the Fulton County outbreak on pumpkins was unusual for the Great Lakes region.
