Re: Does Extra Drone Comb in Hive Increase Varroa Mites?
Controlled studies have shown that varroa reproduces twice as fast in drone brood (2.6 mites per cycle) as it does in worker brood (1.3). Studies have also shown that there can be as many mites raised over the brooding season in 50-60 drone cells as could be raised in 1000 worker cells.
If you use culling of poor comb to reduce drone cells, you reduce the rate at which the mite population grows. If you control on which comb the drones are produced, you can remove them, freeze them and kill the mites that are in their cells. The drone comb frames can then be reused after freezing. Google Drone Brood removal by Nick Calderone.
The Swiss have done studies that say drone brood removal works early in the year , but that it becomes less effective when mite populations are above 700 mites. This is why it is best to combine drone removal with other methods to keep varroa numbers down. The goal is to prevent the varroa from reaching the point that they damage the colony.
I think you are correct when you try to limit growth by culling bad comb, small reductions in the percentage of growth can make a difference by the end of the brood producing season.
38 years - 25 colonies, 32 Nucs - IPM disciple - Naturally Skeptic