This year I am going to treat both fall AND spring. I use HopGuard, 3 applications, 7 to 10 days apart. I put solid boards, smeared with Vaseline, under the screened bottom boards to catch the dead mites. These are the mites that were on the board after 24 hours.
Close up of mites. They are the blood red ovals.
I will treat twice more this month. Meanwhile I am feeding them 2:1 syrup and giving them pollen patties. I want to make sure they have plenty of food to get them through the winter and raise their winter brood.