Vegetable Crops Hotline A newsletter for commercial vegetable growers prepared by the Purdue University Cooperative Extension Service

Downy Mildew Update

August 4, 2015 - Included in Issue: 603

By: Dan Egel

On July 22, I announced that downy mildew had been observed on watermelon in Knox County in southwestern Indiana. This article https://ag.purdue.edu/arp/swpap/VeggieDiseasesBlog/Lists/Posts/Post.aspx?ID=48 describes the outbreak and management options. Below, I will discuss the whereabouts of additional downy mildew outbreaks on cucurbits.

Downy mildew has now been reported on cucumber in Knox and La Porte County Indiana. Downy mildew has been observed on pumpkins in Mason County in central Illinois. In addition, several counties in Kentucky and Michigan have reported downy mildew, primarily on cucumbers. A photo of downy mildew on pumpkin is shown here for reference (Figure 1).

You may follow the development of downy mildew of cucurbits on this website http://cdm.ipmpipe.org/.

Downy mildew causes bright chlorotic lesions on pumpkin leaves.

Downy mildew causes bright chlorotic lesions on pumpkin leaves.

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