Powdery mildew is a common problem on indoor plants during the fall and winter months. |
Signs: White, thread-like fungal growth develops on leaves, stems, buds and flowers, and later develops into a white to gray powdery coating that can be rubbed off with fingers. Powdery mildew on poinsettia leaf. Photo by Plant Disease Clinic |
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Powdery mildew on lilac leaf. Photo by Chad Behrendt |
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Powdery mildew on begonia leaf. Photo by Plant Disease Clinic |
| Causal organism: | Variety of fungi |
| Method of dispersal: | On air currents or water splashes |
| Infection point: | The fungi causing powdery mildew grow only on the surface of the plant, and do not invade the tissues. |
| Control: | Prune out affected leaves, if possible. Gently wash affected areas with water and rub off fungal growth. Maintain plants in a well-ventilated area with low humidity. |
| Labeled fungicides: |
Not recommended |
| Comments: | Powdery mildew infection will rarely kill plants, though they will use the plants' nutrients, reduce photosynthesis, and reduce growth of the plant. Severely infected plants will be more susceptible to other diseases and pests. |
| Additional Information | Back to Problems Affecting Multiple Hosts | Back to Houseplant Diseases |
