Alcohol wash mite count calculator

Mites per 100 adult bees. Count the mites that drop out of the wash, divide by the number of bees in the sample, and multiply by 100. Twelve mites in 300 bees is 4 %. The calculator divides by the bee count you enter, never by a fixed 3.

A level half cup of lightly packed bees is about 300 bees. That is the sample the Honey Bee Health Coalition guide is built around, and the guide says a smaller sample is not accurate. Take the bees from one to three brood-nest combs, and find the queen before you shake. Some extension protocols use 400 bees; the calculator works with whatever count you enter.

Alcohol or soap wash is the method the HBHC guide prefers: it gives the more accurate count, and the bees in the sample do not survive it. A sugar roll returns the bees alive but is the less reliable count (HBHC). Whichever you choose, use it every time so the trend in your log means something.

Enter the count you have; the calculator divides by your number. A sample under 300 bees is not accurate (HBHC), so read the result as a rough check and wash a full half cup next time.

It is Bee Community's own warning band, not an HBHC category: a short band just under the threshold for the phase you picked, printed with the result. In the app that hive's status turns amber with the prompt to log a wash, so the next count comes sooner than your monthly check and you have looked at which registered products fit your temperatures and supers before it crosses the line.

The same count means something different at different points in the colony's year, so the HBHC guide sets its thresholds by colony phase — dormant, population increase, peak population, population decrease — rather than by calendar month, and it says the numbers vary by region. Several extension services publish their own variants; the footnote on this page lists the ones on file, for reference only. When in doubt, ask your state apiary inspector or extension office which threshold they use.

That is the guide's signal to act, not a diagnosis. Pick a registered product that fits your daytime temperatures and whether honey supers are on, read the whole label before you open the package — the label is the law — and wash again after the treatment ends to confirm the count came down; the result above gives the recheck window when a count is over the line. Two failed treatments in a season is a reason to call your state apiary inspector.

About once a month through the active season, starting when the colony begins to build in spring, and at least four times from peak population through the late-summer decline. Wash before a treatment so you have a baseline, and again after it ends to see whether it worked. The app turns that cadence into reminders from your own log.

No. A sticky board counts mites that fall onto a board over a period of days; it is not a count per 100 bees, so it does not map onto these thresholds. The app records it as monitoring only. Use a wash for the number you compare against the threshold.

The thresholds are the ones published by the Honey Bee Health Coalition in Tools for Varroa Management, 9th edition; the edition date is printed under the table. The guide is licensed CC BY-NC-ND 4.0, so this page states the numbers as facts in its own words and copies none of the guide's text, tables or figures. The watch band is Bee Community's own addition. Bee Community is not affiliated with or endorsed by the Coalition.