Hello Bonnie,
Thanks so much for your inquiry in regards to the health of your plant. Powdery mildew is caused by a huge range of fungi that generally each type has a single type of plant (or similar group of plants) that it will attack. But more important is what causes it, and how to treat it once symptoms arise.
Powdery Mildew in your case is probably being caused by your plants not getting enough water (dry soil- which is probably happening quicker than normal, because your plant is being exposed to outside environments in the carport), and being in the humid air of Florida this time of year.
To control your problem start by watering more often (but not overhead watering!) and removing infected leaves as they show up. Use of a sulfur based fungicide can help for the short term. You can also move it indoors (for less humidity) to see if that helps clear up symptoms.
Thanks so much for your inquiry Bonnie, and please get back to me if you have further questions or concerns in regards to your plant(s)!
Best regards ~ Ian
