Beekeepers use something called a 'Shook Swarm' to help reduce disease and pests in bee colonies. Basically, it is like a 'forced spring clean for bees!'
Many pests and diseases use the Brood combs (where the Queen lays her eggs and the baby bees are born) to multiply and live, so the idea of a Shook Swarm is to replace all the brood frames with new clean ones for the bees to use in a clean new hive... the plan being, all the pests such as Varroa are left behind!
Also, after each new bee emerges, the cell becomes very slightly smaller as she leaves behind her cocoon, after a few seasons, these smaller cells lead to smaller bees which are much less likely to winter well and resist disease.
Many pests and diseases use the Brood combs (where the Queen lays her eggs and the baby bees are born) to multiply and live, so the idea of a Shook Swarm is to replace all the brood frames with new clean ones for the bees to use in a clean new hive... the plan being, all the pests such as Varroa are left behind!
Also, after each new bee emerges, the cell becomes very slightly smaller as she leaves behind her cocoon, after a few seasons, these smaller cells lead to smaller bees which are much less likely to winter well and resist disease.
The old frames, which sadly contain stores and brood, are dispatched quickly in a steamer... it is a very difficult thing to do, but the bees soon recover and this method of pest and disease control means we need to use less harmful chemicals on our bees.