How to Check for Varroa Mites in Your Beehive

Varroa mites are a widespread problem affecting beekeepers in New Zealand, Australia, and beyond. These parasites latch onto bees, injecting saliva that transmits harmful viruses while also feeding on their body fats. Left unchecked, Varroa infestations can severely weaken colonies, leading to deformed wings, reduced lifespan, and colony collapse.

Early detection and treatment are crucial for keeping your hives healthy. Here are some effective ways to check for Varroa mites: 

1. Inspect Drone Cells & Bee Behaviour

  • Open capped drone cells and check for mites inside. (Use an uncapping fork)
  • Look for deformed wings—a clear sign that mites have been present for some time and have spread viruses.
  • If you see bees crawling on the ground instead of flying, they may be heavily infected with viruses from the varroa.

2. Use a White coloured Board under a Ventilated Floor

  • Locate a white tray or Corflute sheet and spray around the edge with cooking oil or silicone to stop sick mites walking off it.
  • Place under the hive’s ventilated floor for 24 hours. For unvented floors, use Corflute on the floor, directly below the brood box.Mites naturally fall through the mesh, giving you an idea of the infestation level.
  • Check the board for varroa mites. Use a magnifying glass if necessary. 5–6 mites per day is normal, but higher numbers indicate trouble.

3. Icing Sugar Shake (Non-Lethal Test)

  • Take half a cup of bees (about 200 bees) from the brood frames and place them in a jar with a mesh lid. (Be careful not to get the queen)
  • Add icing sugar and gently roll the bees for 40 seconds to dislodge the mites.
  • Shake the sugar and mites onto a white surface and count the mites.
  • A count of 1–3 mites is manageable, but 4–5 signals it's time to treat. If you find 10 or more mites per 200 bees, immediate action is needed.

4. Alcohol Wash (Most Accurate Method)

  • Place half a cup of bees in a Varroa check cup with methylated spirits or alcohol.
  • Swirl for one minute—this kills the bees but removes all attached mites, allowing for an accurate count.
  • Count the mites at the bottom of the cup.
  • While this method is highly effective, some beekeepers avoid it due to the loss of bees. However, performing even one alcohol wash per apiary can provide critical data.

5. Vaporization Test

  • Apply an oxalic acid vapor treatment and observe how many mites fall onto the bottom board afterward over 36 hours.
  • It is best to fit a whiteboard on the base if there is a solid floor or under the base if it is vented. See No. 2.
  • Regular vaporization can help control mites while also serving as a monitoring tool.

Final Thoughts

Regular mite checks are essential to keeping your colonies healthy. Monitoring and early intervention can make all the difference in preventing colony losses.

By staying vigilant and using these test methods, you can keep your bees thriving and one step ahead of Varroa.

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