And Varroa destructor mites. If Beewise can figure a simple but effective method for eradicating them from the hive, they will solve one of the biggest stressors on bees. Beekeeping, as has been said, is really pest management.
These can be killed easily with vaporized oxalic acid in two treatments spaced a week apart (iirc, dad keeps bees not me). This pretty much eliminated any hive loss for years now, and we’re convinced this is the fix for colony collapse disorder (at least in our area).
Ants have some methods of doing this exactly, with some guards at the entrance carrying off infected ants before they can enter. Seen in the documentary "fantastic fungi".