Lesson 55: Counting Mites

How to measure your colony's mite level, step by step

You can't manage what you don't measure. Most mites hide under brood cappings, and by the time you see mites or sick bees, the problem is already serious (lesson 54). The only way to know your colony's mite level is to take a sample and count.

The standard measure is mites per 100 bees, often written as a percentage ("3 mites per 100 bees" = "3%").

The sample: 300 nurse bees

For the alcohol wash and sugar shake, you need about 300 adult bees from the brood nest (lesson 40):

• Take them from one to three brood frames, where mites ride on nurse bees.
• Check every frame for the queen first, and set aside any frame she's on.
• 300 bees ≈ ½ cup of lightly packed bees. Fewer than 300 won't give an accurate result.
• Two ways to collect: shake bees from the frames into a tub, wait a moment for older bees to fly off, then scoop ½ cup; or roll a jar down the face of the frame so the bees tumble in.

Method 1: The alcohol (or soap) wash (most accurate)

The alcohol wash kills the sample (about 300 bees, a tiny fraction of a colony), but it's the most accurate and reliable method and the one the Honey Bee Health Coalition recommends.

You need: a wide-mouth jar (a quart canning jar) with a lid, a mesh screen (#8 hardware cloth) that fits the lid, a ½-cup measure, a white tray or tub, and rubbing alcohol (70%), ethanol, low-sudsing soap solution, or windshield washer fluid (at least 40% alcohol).

1. Pour enough alcohol into the jar to cover the bees by a couple of inches.
2. Add ½ cup of nurse bees to the jar and close it.
3. Shake or swirl vigorously for at least one minute. This knocks the mites off.
4. Pour the liquid through the mesh into the white tray. The screen holds back the bees; the mites wash through.
5. Refill with fresh alcohol and repeat once or twice more, adding to the same tray. Repeating makes the count more accurate.
6. Count the mites in the tray: small reddish-brown ovals.

Method 2: The powdered sugar shake (bees survive)

The sugar shake doesn't kill the bees, but it's less accurate and takes practice.

Don't use it in humid weather or during a strong nectar flow: damp sugar sticks, and mites stay on the bees, so you'll undercount.

1. Put the 300 bees in a jar with a screened lid (#8 mesh).
2. Add about 1–2 tablespoons of powdered sugar (sifted is best).
3. Roll and shake the jar for about a minute to coat all the bees.
4. Set it in the shade for 2–5 minutes. The bees groom themselves and mites lose their grip. Don't rush this.
5. Turn the jar upside down and shake it hard, like a salt shaker, over a white plate or tray until no more sugar and mites fall out.
6. Repeat once with the same bees for a better count.
7. Mist the sugar with water to dissolve it, then count the mites.
8. Return the bees to the top of their hive (their sisters clean them off).

If the bees aren't evenly dusted with dry sugar, the test didn't work.

Doing the math

Mites counted ÷ number of bees × 100 = mites per 100 bees (%)

With a standard 300-bee sample: mites ÷ 3 = mites per 100 bees.

Example: you count 12 mites. 12 ÷ 300 = 0.04 × 100 = 4 mites per 100 bees (4%).**

Lesson 56 explains what number means it's time to treat.

Method 3: The sticky board (a rough check)

A sticky board catches mites that fall naturally off the bees.

1. Slide a sticky board (a card coated with a tacky substance or petroleum jelly, ideally printed with a grid) under a screen onto the bottom of the hive. The screen keeps bees off it. A screened bottom board with an insert tray works. Don't block the entrance.
2. Leave it in for 3 days.
3. Count the mites and divide by the number of days to get mites per day.

USDA uses about 30 or more mites per day as a sign treatment is needed. But sticky boards are less precise than a wash or shake: counts vary with brood emergence and colony size. Use them for a quick check, or to watch a treatment working, and confirm with an alcohol wash or sugar shake.

Just looking for mites on bees is the least reliable method of all. If you can see them easily, there are already a lot.

When and how often

• Sample regularly through the active season. The Honey Bee Health Coalition recommends monthly from the spring build-up, or at least four times from the summer peak into the fall decline. Check more often in fall, as often as every three weeks.
• Sample again after every treatment to confirm it worked.
• In winter, leave colonies alone (a sticky board is the least disruptive check).
• Sample every colony if you have fewer than about ten. Colonies in the same yard can differ a lot.
• Record every count (lesson 41).

How it looks: A sugar shake in progress.

What you're counting: varroa mites collected from a mite check.

Collecting a bee sample for a mite count.

What to remember

• Measure mites per 100 bees from 300 nurse bees (½ cup), never including the queen.
• Alcohol wash = most accurate (kills the sample). Sugar shake saves the bees but is less accurate and fails in humid weather or strong flows.
• Mites ÷ 3 = mites per 100 bees (for a 300-bee sample).
• Sticky boards give a rough mites-per-day check; confirm with a wash.
• Sample monthly in season, every 3 weeks in fall, and after every treatment.

Quick check

1. How many bees are in a standard mite sample, and about how much is that?
2. You count 9 mites in a 300-bee alcohol wash. What's the mite level?
3. Why shouldn't you do a sugar shake during a strong nectar flow?

Show answers

1. About 300 bees, roughly ½ cup. 2. 9 ÷ 3 = 3 mites per 100 bees (3%). 3. Damp conditions and nectar make the sugar sticky, so mites stay on the bees and you undercount.

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Adapted from: Honey Bee Health Coalition, Tools for Varroa Management (9th ed., 2026), "Monitoring Varroa Mite Populations"; USDA Agricultural Research Service, How to Monitor, Sample, and Treat for Varroa, Alcohol Wash, Sugar Shake, Sticky Board and When to Sample; Penn State Extension, Methods to Control Varroa Mites (2025); UF/IFAS Extension, Welcome to the Apiary! (4H446).

Photos: sugar shake, Jürg Vollmer, CC BY-SA 4.0 · mites in vial and sampling, Starr Environmental, CC BY 2.0 (all via Flickr).

Adapted from university Extension sources. Experienced Georgia beekeepers are reviewing these lessons. See something that doesn't match your experience? Tell us.