It’s very important to treat your bee colonies for varroa mites before they make their “winter bees” at the end of the season.
Varroa mites feed on larvae and cause honey bees to have shorter lifespans. If your colony raises winter bees while they have mites in the hive, those winter bees will not survive through the whole winter. As bees die earlier, the winter cluster gets smaller and at some point, the colony doesn’t have enough bees to keep warm through winter (even though they may have plenty of honey nearby, they cannot reach it because the cluster is too cold).
If you already removed supers you can still treat for mites with the same two products or even use Oxalic Acid.
Formic Pro is more convenient for the beekeepers that have one to 10 hives, with Oxalic acid becoming more convenient for beekeepers with more hives.
This link will take you to the section of of the online store that shows the products and tools we have available: https://beemaniacs.com/product-category/bee-health/