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The disease occurs when cooler than normal temperatures prevail during the reproductive stages of the soybean plant. Powdery mildew begins as small, circular areas of white, powdery mold growth on the upper leaf surface. These areas enlarge to cover large areas of the leaf surface (both upper and lower surfaces) and may develop on stems, petioles and pods as well. When severe, all above-ground portions of the plant appear to be covered with white to grayish white, powder-like mold growth. Heavily infected leaves may yellow and drop prematurely.
Selecting resistant varieties may help control powdery mildew. |
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