I have a purple shamrock that I bring in in the Winter and recently I noticed that it was looking really bad so I took a closer look. It looks like it might have powdery mildew but I'm not sure. Everything I've read so far make it sound like the mildew should be on top of the leaves. My plant has white powdery circles on the underside of the leaves and the top of the leaves have dark brown/black dried up spots...sort of looks like blight spots. Does this still sound like powdery mildew and what should I use to get rid of it? I have already taken off lots of infected leaves but almost the whole plant is infected so that would leave almost no leaves. Should I just cut the whole thing back and let it start over. Help please!