when the hive shuts down for the winter and brood rearing stops, shouldn't the varroa die off. i've been wondering about this and can't seem to find an answer. still another question i have is what mite count do you find acceptable going into winter, say in terms of mite fall/ per 24 hrs. 10, 20, 100 ? tia.
The adult varroa over winter on the adult bees. The 24 hr mite fall numbers differ depending where you are located. Check with local beekeepers or your states inspection service.
Depending on location, brood rearing may not stop. It slows considerably, often to just a small patch in the center of the cluster. In my climate - central Indiana - the queen may stop laying for a couple weeks, but that's all. That's why it's important to get the mite counts knocked down before winter, otherwise there are a lot of mites concentrated on a small amount of brood and that's when we lose hives to varroa.