Spider mittes and mildew

Hi, i have an indoor and after 5 days of holidays when i back saw some mildew and advanced spidermitte problem..

Now i'm on 4th week of flower, so.. Can i fumigate? Or it's too late?

pm can usually be cleared up with a spraying of diluted skim milk, or a weak h2o2 solution. then improve your ventilation, and do a little wipe down of the general area with some bleach water.
once a plant has started to flower, the only thing i like to use is spinosad, and i try to get as little on the buds as possible. if its a bad problem i'll take 1/2 tblsp and add it to my water, to use as a systemic pesticide, but i don't like to do that if i don't have to. its supposed to totally dissipate in a week or two, but i don't trust any pesticide farther than i have to