Re: Apivar of Oxalic Vaporization for extreme mite count?
Grapeman, I just came through the same thing. Do as psm1212 suggests and hit the entire apiary with OAV on a tight schedule. The mites will continue to drop in large numbers for the first several treatments so do not get discouraged when you see all those mites falling. Keep at it until the drops are near zero and you will be giving the bees their best chance at surviving. Plan on around 6 or 7 treatments 3-5 days apart. Feed both syrup and brood builder pollen patty and you might get them to produce another round of brood before they shut down. You are about a month behind the point where you want the hive to be nearly mite free, but the bees are pretty resilient if you help them a little. Make feeding shims and keep the hives well supplied. If they make it to Feb., be prepared to give them some brood and bees from your other hives.
Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.