White powder Mildew. If you have found a few white spots on your plants, join the club. These white spots can appear on most plants. Don't worry too much, this mildew is generally not fatal to plants. It will cut down on photosynthesis of your plant. These mildews are a type of fungi, however there is nothing fun about this guy. There are several species of the mildew. They all function in the same fashion. The different types of mildew don't affect other plants. If you have mildew on your coleus, you wont get the same species on your jade plant. What causes white powder mildew? High humidity, or just a general dampness around the plant. Poor air circulation Make sure that you take care of the mildew as soon as you can. If you do not your plant can be in a bit of danger. It won't receive full photosynthesis that the plant needs, and won't be able to process the nutrients properly. I'll wait till winter. If you think the winter will solve your prob...