Someone on these boards suggested Regalia for PM. I figured I'd give it a try. My plants are about 3 feet tall in veg, 36 plates total, 6 of them had some light PM spots. I applied Regalia per instructions and waited a week. The plants that had PM on them had further progression of PM and many of the other plants that didnt have PM are showing signs of PM.
Long story short: dont waste your money.
Long story short: dont waste your money.