The process of removing the queen and letting the colony go queenless and raise a new queen interupts the Varroa Mite reproductive cycle. More importantly this break in the honey bee brood cycle has the Varroa mites exposed on the comb or bees for a period of several days. This is an opportune time to apply Varroa mite treatments. Understanding this vulnerablility of the mite will make any treatment more effective to reduce mite numbers.

queen removed = Day 0 last eggs laid,
bees select 1 day old larva (Day -3),
Day 8-13 introduce new queen cell from other source if desired,
Day 13-16 queen emerges and destroys other queen cells
Day 21-24 the last of the workers and drones emerge
Day 21 start sugar dusting cycle of every 3 days for 10 days window to capture mites that have no brood,
Day 30 check for eggs,
Day 35 check for larva.
A colony with queen removed on 12-15 AUG will have emerging brood on 1-4 OCT.

To download the picture above illustrating this process click here.