Want to control varroa, cage the queen using a push in cage for 10 days to 2 weeks, do some sugar shakes, and turn the queen loose. The interruption in the brood cycle will put the varroa onto the bees, the sugar shakes will make them fall off.
That is if you have a varroa problem.
My fix has been to go with bottomless hives. I slide a mite board under the hive every few weeks to check for them but to date, after a big brood cycle interruption caused by near starvation (dearth), I have no mites. At least I can't ever find any on the mite boards when I check. So if I have any the population is too low to identify. The bees have also helped by keeping the brood nest fairly small all summer.
My observations are that brood cycle interruption combined with open bottom hives goes much further than any other method for controlling varroa. It also gives the bees an opportunity to develop resistance or adapt to the parasite. If they show up, I'll interrupt the brood cycle and treat with a series of sugar shakes and be good to go for another year of 2, but I honestly expectd to never have to worry about varroa again.
The small (natural) cell from foundationless frames probably helps too. Notice that I'm using more than one approach, as needed, to do the job. There is no solo silver bullet.