Varroa Mites

Varroa mites (Varroa destructor and V.jacobsoni) are serious external parasites of honey bees. Varroa mites feed and reproduce on adult bees as well as their larvae and pupae in the developing brood. While feeding from them, the transmit numerous viruses and cause bee brood to emerge from the brood malformed and weakened.

Varroa mites are parasitic mites which survive through feeding off their host, the honey bee and their brood. They are visible to the naked eye, and look somewhat like a tick. Adult female Varroa mites are oval, flat, and red-brown in color. She will lay her eggs more frequently on drone brood rather than on worker brood, due to its longer brood cycle.

Varroa mites are known to spread a virus that causes deformed wing virus (DWV), parasitic mite syndrome (PMS) and are associated with colony collapse disorder (CCD).

Symptoms depend on the level of Varroa mite infestation, the number of brood in the colony, and potential of viral infections being transmitted by the mites. For low infestations in colonies, early signs of infection normally go unnoticed as bees show very few symptoms. As Varroa mite infestations increase, signs will become more apparent and widespread in colony members. The newly-emerged bees may be smaller than normal, have crumpled or disjointed wings, and shortened abdomens. Other symptoms include Parasitic Mite Syndrome (PMS), which causes reduced coordinated social behavior, distortion and deformation of bee parts, scattered brood frame with dead or uncapped brood and rapid honey bee de-population in the colony. Most infested colonies die within 1 to 2 years if the beekeeper does not take actions to get rid of the mites from the hive.

Transmission

Varroa mites are transported from colony to colony by drifting or robbing bees, swarms and absconding colonies, the transport and movement of hive and beekeeping equipment, used beekeeping equipment, packaged bees and queen bees.

Symptoms

  • Scattered brood
  • Mites visible on adult bees, brood, or hive debris
  • Crippled bees
  • Crawling honey bees
  • Reduced colony population
  • Weight loss
  • Impaired flight performance
  • Reduced lifespan
  • Deformed wings and abdomens

Cause

  • pest - varroa destructor

Diagnosis

  • Clinical signs
  • Physical examination - of brood
  • Sugar shake or either roll
  • Alcohol wash
  • Sticky board

Treatment


  • Drone brood sacrifice
  • Powdered sugar dusting
  • Brood interruption
  • Downsizing of the brood cell size
  • Varroa mite control entrance
  • Drone comb or bottom screens to trap Varroa mites.
  • Overnight sticky sheets
  • Screened bottom boards

Prevention

  • Screened bottom boards
  • Mite-tolerant stocks
  • Drone-brood trapping
  • Treatment of inert dusts

Article Reference

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