Figure 1. Downy mildew of pumpkin causes yellow, angular lesions as viewed from the top of the leaf.
Downy mildew was observed on pumpkins in Daviess, Knox and Washington County. Evenings and mornings with heavy dews and fogs may help the disease to spread. Whether to apply fungicides for this disease will depend in part on when growers plan to harvest. In addition to the cucurbit downy mildew outbreaks reported in the last issue of the Vegetable Crops Hotline, the disease has also been reported in White County Illinois, directly west of Evansville, IN. Photos of downy mildew lesions on the top (Figure 1) and bottom (Figure 2) of pumpkins leaves.
Figure 2. During or shortly after moist conditions, downy mildew of pumpkin will cause a fuzzy-like fungal growth on the underside of the leaf.