|A friend gave me 3 minature rose plants and I cannot get rid of the powdery mold. I'm not sure what it is called but it looks like the plants were sprinkled with powder and leaves turn yellow. I thought I got rid of it 3 times but it keeps on coming back.|
|You named the culprit - it's powdery mildew! It's one of those persistent garden companions. It loves roses, among other things. I'm guessing that these are potted plants growing inside, so the mildew spores are probably present on growing and fallen leaves, and hit your plants when conditions to turn to the mildew's favor.
You've won previous battles with it, and that's the name of the game - the war goes on and on. The mildew will win if you loose interest or patience with the control regime. It requires that you keep vigilant, washing top and bottoms of leaves weekly with water. If you have a compost pile, make some compost tea and spray it on leaf surfaces every couple of weeks, or use baking soda-oil spray (1 tsp. baking soda and 2.5 tsp. summer oil in 1 gallon of water) sprayed once per week. A commercial organic alternative is Soap Shield Fungicidal Soap from Gardens Alive (5100 Schenely Pl., Lawrenceburg IN 47025; ph# 812/537-8650). Also, just keep your roses healthy through proper care, since they'll be more resistant to disease. Let us know if you need any further specifics, and good luck!