What is varroa and how do I treat it?
Varroa destructor is a parasitic mite that feeds on bees and spreads the viruses that actually kill the colony. Measure before you treat: an alcohol wash or sugar roll of about 300 bees, counted as mites per hundred. Above roughly three per hundred, treat. Untreated colonies typically collapse within one to two years.
Step by step
- Half-cup scoop
- Alcohol wash jar or icing sugar
- Approved varroa treatment
- Shake about 300 bees from a brood frame into your jar — roughly half a cup. Check the queen is not on the frame first.
- Wash the sample in alcohol for the most accurate count, or roll it in icing sugar if you want the bees back.
- Count the mites and express the result as mites per hundred bees. A number is the point: 'a few mites' is not a measurement.
- Treat when the count passes roughly three per hundred, using a product licensed where you live.
- Follow the label exactly on temperature and duration, and never treat with honey supers on the hive.
- Re-test after the treatment period ends. A treatment you did not verify is a treatment you cannot rely on.
The full lesson
Varroa is a brown, flat, external parasite mite that attaches to the bodies of honeybees and can be seen with the naked eye. This parasite feeds on the fat body
and fluids of bees and larvae, directly destroying their immune system and weakening them. Varroa enters the worker,
and especially drone brood cells, just before they are capped to reproduce inside the honeycomb. Inside the sealed cell,
the female Varroa lays her eggs on the developing larvae, where a new generation of parasites grows. Young bees attacked by Varroa inside the cells are born without wings, with missing legs,
or stunted in size. Varroa doesn't just drain energy, it spreads deadly diseases from bee to bee, especially the deformed wing virus.
In an untreated hive, the Varroa population multiplies exponentially every month, causing the colony numbers to melt away. To check the Varroa infestation level,
look for mites falling onto the sticky bottom board, or use the powdered sugar test. If Varroa mites are left uncontrolled, that colony will completely collapse
and die within one to two years. Varroa cannot be fully eradicated, however, it must be kept below the economic threshold, using proper methods in spring and autumn.
This lesson is also in the app, along with the other twenty-nine.
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1:40Lessons and forum answers describe beekeeping practice and peer experience, not veterinary guidance. Treatment thresholds, inspection timing and disease management vary by climate, subspecies and local regulation. Diseases that are notifiable where you live must be reported to your national bee inspectorate.