Since I seem to have brood all the time the temp is above 50F in my area, I dont know when I would use oxalic acid as the bees are either raising brood, or in a cluster. The acetic acid part jumped out at me, but alas, it provides no "real" info.
The lack of detailed info on acetic acid, other than "it is the greatest thing since sliced bread" is really fustrating and leaving many people very skeptical. When essential oils was being pushed as the answer for all problems, there were at least some people trying to provide some type of scientific testing (albeit low tech and questionable). Is there any evidence that acetic affects varroa in capped brood? I know oxalic doesn't and formic does, but where does acetic fall.
When I first switched to using oxalic acid, I had heavy infestation and plenty of brood in the hives. I vaporized 3 times at 7 day intervals as Michael described and I had no noticeable brood damage. Now I just vaporize once a year in the Fall and have not lost a hive to varroa in 3 years.
I also question the statement by the relative of the vinegar vaporizer maker.
At this time, we are happy to provide this machine to those who are seeking a chemically free alternative that successfully and safely treats their hives. We are not looking for an endorsement from any one entity. Frankly we have a great product with a proven track record of customers who are increasing their annual honey yields while reducing their losses from dead hives.
chemically free??? If acetic acid isn't a chemical, than neither is oxalic acid. I know they try to use the pickle example for it being safe, but I can also put together an arguement for oxalic acid that the quantity I use is the same as 3 1/2 cups of chopped spinach.
As far as a proven track record, I'm not convinced at that either. Yes there are some here that swear by it (and I'm happy for them), but go over to Beesource and do a search and you will find just as many that say it didn't work for them. I lived through similar times with essential oils. There where many that claimed great success, others biased by their desire to want success, and those that had little to no success.
I don't want to discount it, but I just don't see the details yet for me to consider buying in on the claims. Why does acetic help nosema, fowl brood, chalk brood and hive beetle but yet the other organic acids don't? Until some data (even rudimentary) is provided to back up some of these claims, most will remain skeptical from being burned by snake oil salesman claims in the past.