Cucumber downy mildew was confirmed in Delaware and Franklin counties this week. Cucumber and melon growers in northern and central Ohio should assume that downy mildew risk is high and should protect their plants with fungicides. Since downy mildew has also been reported on cantaloupe and cucumber in Kentucky (Lexington area), it is likely that theses crops are also at risk in southern Ohio. A list of recommended fungicides was posted here on June 28. Additional information can be found in the Midwest Vegetable Production Guide for Commercial Growers.
We still have not confirmed downy mildew on squash or pumpkins in Ohio, but we continue to monitor our sentinel plots, field research plots and commercial fields. We will be happy to check out a pumpkin or squash sample, or any cucurbit sample, for downy mildew – please send affected leaves in a box by priority mail or 1- or 2-day courier, or drop them off at out lab: Vegetable Pathology Lab, OSU-OARDC, 1680 Madison Ave., Wooster, OH 44691; ph. 330-263-3838.