It's not in SoCal but that's where I grew up and learned to deal with mold(mostly botrytis) and bug(caterpillars).
If PM is a real bad problem there is a product called eagle20. It's definitely not organic but it fucking works! I've never used it outdoors, but after a real bad indoor problem, I had to use it and haven't seen PM in 3 full indoor cycles. It works/effects bud rot too but that was never a problem indoors for me. Expensive too. Just be preventative with serande and you should be fine for al mold problems.