You can clearly see some small black dots in the 2nd picture,.... I guarantee those dots MOVE!!!!
It is NOT Powdery Mildew ;)
Preventing mites is the best method, but for resolving them once you have them, and you certainly seem to, Neem is my #1 Mix per the bottles instructions and spray every 3 day's to knock down the infestation, then weekly as a prevention measure.
Also, make sure your grow room is pretty much hospital clean, don't go directly into your room after working out doors, shower and change clothes to prevent a bug from hanging on you.
Any new cuttings should be quarantined for 2 weeks and watched for bugs or disease before introducing to your proper grow.
Low temps and high humidity will slow them down, but like a buddy of mine is realizing, it wont get rid of them!
Someone will eventually say, "No Pest Strip" It works initially, however mites can become immune to them, and the strips only keep them down to a minor infestation at best.
Neem Neem Neem, Weekly until 2nd week of flower,... but not after that since it'll F up the taste of the buds something fierce! But by then you shouldn't have mites anymore ;)
