Varroa mites (Varroa destructor) are external parasites that attack both honey bees and brood. They suck the blood from both the adults and developing brood, especially drone brood. This weakens and shortens the bee’s life. Emerging brood may be deformed with missing legs or wings. Untreated infestations of varroa mites will increase and may kill colonies. If the colonies are not examined for
mites, losses may be mistaken for winter mortality or queenlessness.
Varroa mites transmit dangerous viruses and bacteria :
Varroa mites transmit pathogens like viruses and bacteria which are damaging to bee health. This parasite has wiped out entire populations of Western honey bees over recent years. Without human intervention, infestation with varroa means certain death sooner or later for honey bees in Europe and America.
Things are different in Asia, where the deadly mite originated. There, a balanced relationship between the parasite and its original host, the Eastern honey bee or Apis cerana, has evolved over many generations.