Sorry gigs and you're right that shit is nasty. I got some great advice last yr from some of the guys from the outdoor section, tried the milk solution and it worked but wasn't quite stronger enough to hold back the onslaught of PM, so I was fighting a losing battle...but worth it!.
This year I'm hoping to remove that problem or at least lessen the work load keeping it a bay.
I remember reading something about PM a month ago by UncleBen. don't remember all of it but he lists some chemicals/remedies. someone else dealt with this, JJ or Joe M?