Downy mildew was confirmed today in a 3 acre cucumber field in Medina County, OH. Given the outbreaks reported in Michigan in June and an outbreak confirmed in Kent County, Ontario this week, this was expected. Although recent weather has been hot and dry, there have been localized intermittent rainstorms that favor downy mildew spread, and nighttime temperatures are usually cool enough for infection.
Growers in northern Ohio should protect cucumbers and melons with fungicides. Recommendations can be found here.
Thanks to Frank Becker, OSU Extension Wayne County IPM Program Coordinator, for bringing us the sample.