Yeah one year I got a hold of two OG kush clones and both had pm within a few days of putting them in the tent. I thought wow thats odd, the guy I got them from must have had pm...So I tossed them, cleaned the tent out...Started from seed... and those got pm as well, but in mid flower though. Ended up tossing ***everything*** (tent lights fans filters an lb of buds etc) and took a break for a while I was so pissed off.. Its been s while now with no pm visible on the property and none in my tent... (knock on wood)
All it really takes with these arid strains is a poorly timed foliar feed, temp change, poor air flow, or transpiring leaves touching under the right conditions (during a pm outbreak) and boom youre screwed! VPD guidelines are really good to follow, but there is a point where youre returns start to diminish considering other factors. I mean, pm spores are generally in the air at all times.. but some years there are exponentially more..which drastically increases the odds of an outbreak..