HUNTINGTON, W.Va. (WSAZ) -- From a plant's perspective, your house is a desert in the wintertime. On the positive side, diseases that attack the leaves are also discouraged by the dryness. But even a desert has an oasis.
Some nooks and crannies of your house may be wetter than others. It's in these oases that you will find powdery mildew on African violets, begonias and poinsettias as examples.
Powdery mildew fungus will form whitish spots on both leaves and flowers. When the air stays moist and still long enough, the white spots get so numerous that they blanket the plant with a white looking film.
Keep in mind that what you are seeing if your indoor plants suffer from powdery mildew is the same fungus that makes the leaves of dogwood trees and lilac bushes outside also turn white. Severely infested leaves and flowers on house plants will eventually turn yellow or brown and soon will die.
Since powdery mildew loves saturated terrarium-like conditions, a good way to discourage attack is to dry out the environment. This can be done by adding a fan to increase air circulation, use of a dehumidifier, and even increasing the space between pots or a combination of all the above.
If you get the air moving and cut the humidity, your powdery mildew problem will be solved without resorting to chemical weapons. Have a good day.