Why is it impossible to completely eradicate varroa mites from an infected honeybee colony?

It is impossible to completely eradicate Varroa destructor from an infected honeybee colony because the mites have developed highly effective survival and reproductive strategies that allow them to persist despite various control measures.1

The primary challenge lies in the mite's life cycle. During the reproductive phase, female mites enter the brood cells and are sealed inside by worker bees, where they are protected from many external treatments. Furthermore, mites frequently move between hosts during their phoretic stage, making it easy for them to spread within a hive or be introduced from other colonies by "drifter bees" or during raids on other hives.1

Human activities, such as moving food stores between hives, can also inadvertently facilitate their spread. Additionally, some mite populations have developed resistance to chemical miticides, and environmental factors like climate change are exacerbating the problem by shortening winters, which prevents the natural temperature-based suppression of mite populations. Consequently, beekeepers rely on integrated pest management to keep mite numbers below a damaging threshold rather than attempting total eradication.12