Downy mildew on cucumber in Medina County, OH, July 2, 2024. Photo by Frank Becker.
Downy mildew was found today in cucumbers in Medina County, OH. Dr. Mary Hausbeck also reports today the first siting of cucumber downy mildew in Michigan (Washtenaw County). Growers in northern Ohio counties should apply downy mildew-targeted fungicides (Orondis Opti, Ranman, Omega, Previcur Flex, and Elumin) posted here and here in a spray program alternating fungicides with different modes of action/FRAC group. Follow all label instructions. Cucumber growers in other Ohio counties should scout their fields intensively and protect their cucumber crops with protectant fungicides such as chlorothalanil. Melons are also susceptible to the early strain of the pathogen that has appeared in northern Ohio, so these growers should also protect their melon crops with downy mildew targeted fungicides.
If you see suspicious symptoms in cucumbers or melons, you may send (or drop off) samples to the OSU Plant and Pest Diagnostic Clinic in Wooster. There is no fee for this service for Ohio growers thanks to contributions from the Ohio Produce Growers and Marketers Association’s Ohio Vegetable and Small Fruit Research and Development Program.