Question
Hello - I luckily found your website while looking for some help on diagnosing a problem with my african violets.  Some background on them -- I inherited these violets about 1-1/2 years ago when my mother died.  I have cared for them, keeping them in an east-exposure window, fertiizing with special african violet food -- and they have bloomed non-stop the entire time.  I have not repotted them. My mom would be so pleased because she loved her violets.  All 4 plants are quite large and were very healthy until about 1 month ago.  They have developed white spots on the leaves, and stems that looks like snow flakes sprinkled over them.  It is not a leaf discoloration but is actually like a white substance sitting on top of the leaf.  Also, many of the leaves are turning dark and dying off but are very moist, not crunchy and dry.  Is this a fungus?  I don't see any bugs like spiders or gnats on the plants.  From what I have read, I'm afraid it may be terminal - that would upset me since I'm trying to keep them going in my mom's memory. Please give me any suggestions you can.  I think I will get some african violet soil and repot them today in new pots.  I think I could even scrape off the white "snowfakes" but I know that's not the answer to the problem. I'll appreciate your help.  

Answer
Brenda,
I'm almost 100% certain what you have is  POWDERY MILDEW.  This is a very common problem which affects violets, and can be treated easily, but must be treated quickly to prevent damage to the plant.  It is caused by humidity being a little too high, or from condensation on leaves from big variations in day to night temperatures.  The best treatment for a "light" mildew case like your's is to brush away the mildew powder with a very small paint brush, or you can even use a Q-tip with a half-strength solution of rubbing alcohol and water to rub or brush the mildew away.  You want to use this method first to get rid of the powdery substance on the leaves.  There are different chemical substances available in stores which will eradicate the mildew, but for a light case on the leaves only just stick with the brush method.  If you wish, you can substitute Listerene mouthwash 1/2 with water instead of the alcohol.  

For the leaves and stems that are dark and dying there is not much you can do for them except pull them off. Since you are repotting your plants right now take this opportunity to inspect the root system of all your violets.  If there are any soft mushy areas in the roots you will need to CUT these off, because this will only lead to ROOT ROT, and this is a very bad disease which spreads quickly, and there is no cure except to discard the plant.  I know you don't want to do this!

If by chance you decide not to re-pot your violets right now, I still recommend you re-pot any of them with the mushy dark leaves, because then you can cut away any soft, mushy, diseased roots.  By doing this, you will probably save the life of your plant. It sounds as if you are very knowledgeable about violets and their needs.  You could probably give me some advice!

Good luck. I invite you to write in to me anytime you have a question or problem.  And, please let me offer my condolence on the loss of your mother.