One of the most common diseases of pumpkin in Indiana is powdery mildew. Growers are naturally anxious to observe whether the fungicide they have been applying for this disease has been effective. Therefore, many pumpkin growers scout their fields for disease.
Although powdery mildew is relatively easy to recognize, it is possible to become confused. Figure one shows two pumpkin leaves. The bottom leaf has the white, sporulation of the powdery mildew fungus in colonies randomly scattered across the leaf. The top leaf, has silvery coloration primarily along the vein. This latter leaf is a healthy variegated leaf. Some pumpkin varieties show this type of variegation more than others.
Figure 1. The bottom pumpkin leaf has the disease powdery mildew. The top leaf is healthy and has a variegated pattern primarily along the veins.
It may be a good idea to study the photo shown here so that one can tell the difference between a pumpkin leaf with the disease powdery mildew and a healthy leaf that is merely variegated
