Severe damage to cucumbers by downy mildew. Photo by M. Mechling.
Our lab confirmed downy mildew in cucumbers from Jefferson and Perry counties in eastern and central Ohio this week. Given the confirmed distribution in Ohio counties and outbreaks in neighboring states, it is safe to assume that cucumbers are at risk of downy mildew throughout Ohio (see map). We have also reported downy mildew on cantaloupes in two of our sentinel plots in northern Ohio, but have not had any confirmed reports on pumpkin, squash, watermelons or other cucurbits in this state. Downy mildew has not been observed on any cucurbits in our sentinel plot on the OSU main campus in Columbus. This tracks with reporting from other states; cucumber is the main cucurbit crop affected so far. More information about downy mildew outbreaks and the interactive map can be found here. Management advice can be found in earlier blogs posts this summer.
Map of cucurbit downy mildew outbreaks by county. cdm.ipmpipe.org
I am in southern Michigan, Hillsdale county and the downy mildew has killed almost all of my garden this year after the rains we got!