OAV works just fine, if you use it as directed. Keep in mind that it doesn't kill mites under the brood cappings, which at some seasons is the majority of the total mites in a hive. Using OAV requires the use of personal protective gear, including a respirator with ACID GAS canisters, goggles and gloves. And you need a proper wand, some homemade models work just as well as the commercial ones. I haven't got the expertise to make one, so I bought my VArrox wand, which I like very much.
FGMO fogging doesn't work worth beans, but it has an eternal zombie-life on the internet.
There are tons of threads on this site about doing OAV. It is particularly effective as a one-shot treatment when there is no brood, which is typically in early-mid December - it clears the mites out to near-zero levels. But that assumes you have previously protected your winter bees with some kind of treatment in the mid-summer/early fall period. Because even in a near-zero mite environment during the winter, bees weakened when they were larvae and pupae by mites and the viruses they transmit will still die prematurely causing the colony to fail.
FGMO fogging and FGMO with thymol will kill mites mechanically by choking them. The mites inhale the oily fog and suffocate. The kill rate is very poor and cannot control mites. Oxalic acid mixed with water and ran through fogger does not work. Fogger reaches 600 degrees and creates steam + formic acid. Oxalic acid vapor does not leave the nozzle therefore fogger will not create OAV effect. I gathered this information from another thread and I believe it to be true.
A forum community dedicated to beekeeping, bee owners and enthusiasts. Come join the discussion about breeding, honey production, health, behavior, hives, housing, adopting, care, classifieds, and more!