I used to say it was like herpes for plants....Try Eagle20 on all plants at the same time best if they are small plants (less to spray) mix 25 drops to 1- 32 oz spray bottle water
Then address your grow area....if your a small grower in a tent wipe down your entire tent and all equipment with a bleach water solution
If you grow in a large area like I do...use a antifungal bomb FUNGLAFLOR
Remember PM is a airborne spore ...just 1 spore from outside brought in and you have pm