Treating without measuring is the commonest and costliest mistake in Varroa management. Monitoring tells you whether to act, and measuring again tells you whether it worked.

The methods

Alcohol wash

The most accurate. A sample of bees is shaken in alcohol; the mites detach and are counted.

The bees die. That is the cost of the most reliable figure available.

Sugar roll

Bees are rolled in powdered sugar and the mites are dislodged. The bees survive.

Slightly less sensitive than the alcohol wash, but usable repeatedly on the same colonies.

Natural mite drop

Mites falling onto a tray under an open mesh floor are counted over several days.

Useful for a trend, not for a decision. The drop depends on colony size, brood status and weather, which makes the figure hard to interpret.

Opening drone brood

Drone cells are uncapped with a fork and the pupae inspected.

An early warning method: because the mite prefers drone brood, infestation shows here first.

How to take the sample

• Take bees from the brood chamber, where mite levels are representative
• Not from the frame with the queen — and check she is not in the sample
• Use the same method every time; figures from different methods are not comparable
• Sample several colonies, not one

Thresholds

Published thresholds vary by region, by season and by the source consulted. What matters more than any single figure:

• The season: The same count means something different in May and in August
• The trend: A rising count matters more than a single reading
• Local advice: Your association will have figures suited to your region and climate

The late-summer measurement is the decisive one, because it determines the condition of the winter bees.

The step most often skipped

Measuring after treatment. Without it you do not know whether the product worked — and that is exactly what makes resistance visible early.

Recording

Note the date, the colony, the method and the count. Comparison across seasons is what turns monitoring from a chore into a management tool.