Phytol. I used it 2 weeks ago on a flower room that was 3 weeks in......I used a fogger. I sprayed 3 times at 3 day intervals. I defoliated any leaves with mites. I am now almost 6 weeks in and have ZERO mites. It is active against all stages of mites and creates an inhospitable environment as well. It is also a natural fungicide so it gets PM at the same time. I've used Avid,Floramite,Forbid,Shuttle-O and think Phytol may be better. This was the first infestation battled and I think a dip in veg and a light fog going into bloom will completely eradicate mites from a grow. It is organic and I really dig that.
Disclaimer.......It is an oil. It will burn pistils if applied heavy...thus, fogger only in bloom. If you spray with a bottle you will not get the same result. I was fairly heavy handed at the 3 week mark to allow less use in later weeks.....it worked. Fog from low to high to coat bottom of leaves. This also protects the pistils as the leaf blows up and covers them. The earlier you start and the smaller the infestation the better your chances. Get busy, its not impossible. Peace.