Powdery Mildew (5714)

Powdery mildew occurs on many different flowers, woody ornamentals, and trees including roses, snapdragons, African violets, kalanchöe, English ivy, zinnias, photinia, oak, lilac, and begonias. Several different genera of fungi cause powdery mildew. Although usually one genus specifically attacks one or two different plants, some species of powdery mildew (such as Erysiphe cichoracearum) attack a wide range of plants. All the powdery mildew fungi are obligate parasites, requiring live tissue to grow and reproduce. In greenhouses, the fungus survives by spreading from the diseased plants to the new plants of that same crop. If that crop is not grown for several weeks, the fungus dies out and diseased plants must be brought into the greenhouse to establish the fungus again. Outdoors, fungal structures form on leaves and twigs that allow the fungus to survive winter conditions.

For more information, please see this Penn State Fact Sheet

Penn State Horticulture Department

Penn State Plant Pathology Department

For more information on this subject, Please visit the College of Agricultural Sciences Publications Web site.

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