Question
I have 2 potted gardenia plants that both bloomed. I also have a Plumeria, I am noticing white foamy, sticky stuff on them. When I looked at my Plumeria I see little black dots when I scrape them it begins to foam. Can you tell me what it is and how to treat it please? Thank you

Answer
Denise, your plants have been infected with powdery mildew, a fungus disease that is especially prevalent in wet and/or humid conditions.

To combat this disease, you must use a copper based fungicide. I use a product called Soap Shield, and it works great. But it is best to start spraying in early summer to prevent the disease, because once the plant is infected, powdery mildew is extremely difficult to cure. Attached is a link to this product if you are interested.

http://www.gardensalive.com/product.asp?pn=8066&ss=Soap%20Shield  

I hope this answered your question. Good luck, and please write again if I can ever be of assistance.  

Regards,  

Mike