So I started noticing these weird spots about a month ago on my Phals. I also had one Den that had black spots and droppped every last leaf. Per the Sticky link above it appears to be a micro fungus. It is not mites. I have already checked. So I am quarantining these and breaking out the Cleary's as that is the only fungicide I have on hand at the moment. I am also sterilizing trays in bleach water. It's beginning to spread quickly now that warmer weather has arrived. I'll keep you posted.
