Alcohol Wash Mite Count Guide: Step-by-Step Protocol for Accurate Varroa Monitoring

The Honey Bee Health Coalition (HBHC) describes alcohol/soap wash and powdered sugar shake as methods that remove mites from adult bees for counting. Its current guide says alcohol/soap wash is more reliable than powdered sugar shake and that practice improves accuracy with both methods.

What You Need

For a do-it-yourself alcohol or soap wash, the HBHC equipment list uses a wide-mouth jar with a two-part lid and #8 screen mesh, a white tray or similar container, and one of these liquids: ethanol (ethyl alcohol) at a minimum 70 percent concentration, isopropyl (rubbing) alcohol at a minimum 70 percent, methanol (methyl hydrate) at a minimum 70 percent, non- or low-sudsing soap solution, or automotive windshield washer fluid at a minimum 40 percent alcohol. A sampling kit may instead be used according to its manufacturer's instructions.

Sample Collection

Collect approximately 300 adult bees from one to three brood-nest combs, avoiding the queen. The guide equates 300 bees with about 1/2 cup of lightly packed bees and warns that using fewer than 300 will not provide an accurate sample.

Washing Procedure

Add enough alcohol, low-sudsing soap solution, or winter windshield washer fluid to cover the 300-bee sample by a couple of inches. Vigorously swirl for at least one minute. Empty the liquid through mesh that retains the bees while the mites pass into a shallow tray or tub. Refresh the liquid, repeat the swirl-and-strain steps with the same sample, and combine the collected mites before counting.

Calculating Your Infestation Rate

Count the mites, divide by 300 or the actual number of bees in the sample, and multiply by 100 to report mites per 100 adult bees. The HBHC example is 12 mites divided by 300 bees, multiplied by 100, which equals 4 percent.

HBHC Table 1 presents phase-specific bands: dormant, below 1 percent versus at least 1 percent; Population Increase, below 1 percent versus at least 1 percent; Peak Population, below 2 percent versus at least 2 percent; and Population Decrease, below 2 percent versus at least 2 percent. The table labels the lower bands as immediate control not needed and the upper bands as promptly control. These are conservative estimates, not universal cutoffs: the guide says thresholds are evolving, situationally specific, and regionally specific, and advises consulting a local apiary inspector or extension service when possible.

How Often to Sample

The guide recommends sampling monthly beginning with the Population Increase phase, or at least four times from Population Peak to Population Decline. It also says to check more frequently during Population Decrease and repeat sampling after treatment. Sampling results are estimates that can vary among colonies and across the year, so use repeated measurements rather than treating one result as a complete picture. Keep dated before-and-after readings together with the Mite Count Efficacy Calculator.

Primary Source and Limits

This protocol was checked against the Honey Bee Health Coalition, Tools for Varroa Management, 9th Edition (June 11, 2026): monitoring and regional context on printed page 7, equipment and minimum liquid concentrations on page 8, collection and wash steps on page 9, calculation and phase-specific threshold table on page 10, and interpretation cautions and sampling frequency on page 11. The thresholds depend on colony phase and can vary by situation and region; the cited pages do not establish a single year-round or location-independent treatment threshold.