AFTER HARVEST....
I myself would spray the fuckers/ROOM first with Forbid, then 3 weeks later Avid, and then if they aint gone, Id hit them with Oberon, or Floramite.
Don't go into the room until 12 hours after spraying.
Give it 2 months to clear the chemicals if sprayed directly on vegging plants. Not to be used in flowering, and don't forget to not enter room for 12 hours, then ventilate the shit out of it.
THIS WILL KILL THEM. USUALLY ON THE FIRST SPRAYING, but Id recommend a second spray 3 weeks later to make sure none survived the first spraying, because if they do, they will have a possible immunity to the first chemical. Rotationg chemicals makes sure there is no adaptation to the chemicals.
Mites generally have a 3 weeks reproduction time, and these 3 chemicals kill mites for 4 weeks. 1 week longer than the mite reproduction period.