Varroa

In a beekeeping season, the annual progression of varroa in a hive will depend on the number of months that there is brood. Each month, the amount of varroa will double, or triple if there is a significant amount of drone brood. In a Central European climate, with a winter brood break, a hive can survive for about 2 years without treatment, as during the broodless period the varroa population decreases. However, in a Mediterranean climate, without a brood break, infested hives rarely survive a year without treatment; only the "tolerant" ones will endure, which are usually less than 10%.