Pesticide-resistant mites will be inevitable, but the goal of beekeepers should be to stave it off as long as possible. Unfortunately, as many agriculturalists have done in the past, pesticides are now being viewed by the beekeeping community as the single answer to their needs. Using it to the exclusion of other techniques will mean faster development of pesticide resistance in the mite population and subsequent loss of an important control tool. Genetic mechanisms have already been identified, such as elaborate cleaning behavior or shorter development cycles, which might be exploited to prevent build up of large mite populations. Experience in other areas of the world suggests a Varroa infestation will kill a colony in a period of years.
Estimates range from one to two years in the subtropics to as long as seven in temperate areas.
It has been called to my attention that this is not correct, given that damage appears to be greater in subtropical areas where brood is present year around. The more brood available for the mites to use in their own reproduction, the faster their population will build and the sooner the colony will die. In temperate latitudes, broodless times can be used to treat and and fewer treatments may be necessary. Where brood is present year around and mites are protected by being sealed in cells, two treatments some specified time apart may be necessary to reduce populations to acceptable levels . Unfortunately, this information will only come with experience.