You could try something that contains Bayleton. It's hard when there's already an outbreak because you just have to keep at it and it may take 4 - 6 weeks to get rid of it once it's gotten hold, but with the various treatments, it will eventually go away - particularly provided that the environmental conditions improve. I have a goldflame honeysuckle that is rife with PM right now but my crape, that I've battled wtih over 7 years with PM is doing okay since I started spraying early - ie., once it started leafing out.