Does it go thru the capped brood? that is what I was referring to sorry if I did not make myself clear. Treating with brood can be done with all of the mite control methods but most of them will not be very effective unless they are done repeatedly simply because they do not kill the mites under the capped brood.Where do you get the impression that OAV isn't effective with brood?
As for the cost of $20-$30 a year I was not referring to the yearly cost but the cost of the initial equipment to purchase.
Arguing about cost while using your own financial status as a benchmark of affordability is disregarding another person's situation. If a beekeeper cannot afford the initial set up, or choses to use other methods because of the lower costs, and responsibly kills their mites and keeps them in control they are neither cheap nor uniformed.