Varroa Mite Treatment Schedule: When to Test, Treat, and Harvest
Most beekeepers test varroa levels at least monthly through the active season and treat when an alcohol wash or sugar roll shows roughly three or more mites per hundred bees. The most important treatment window in temperate climates is late summer, before the colony raises its winter bees.
How often should you test for varroa?
Test on a schedule rather than when a colony looks sick, because by the time you can see mite damage the colony is usually far past the point of an easy fix. A common routine is a wash or roll once a month from spring through autumn, plus an extra test roughly two to three weeks after any treatment finishes to confirm it worked.
The two standard methods both sample about half a cup of bees, which is roughly 300 bees, taken from a brood frame away from the queen. An alcohol wash kills the sample and is the more accurate of the two; a sugar roll releases the bees but tends to undercount. Whichever you use, use the same one every time so your numbers are comparable across visits.
What mite count means you should treat?
Thresholds are expressed as mites per hundred bees, and the commonly cited action level is around three. Beekeepers generally use a lower threshold going into autumn, because mite growth compounds exactly when the colony is raising the long-lived bees that must survive winter.
| Time of year | Commonly cited action threshold | Why |
|---|---|---|
| Spring | Around 2 to 3 mites per 100 bees | Low counts now compound all season |
| Summer | Around 3 mites per 100 bees | Brood is abundant, so most mites are hidden in cells |
| Late summer, before winter bees | Around 2 mites per 100 bees, or lower | Winter bees must be raised largely mite-free |
| Autumn and winter | As near zero as you can get | No brood cycle left to outgrow the damage |
These are typical figures from mainstream extension and beekeeping-association guidance, and they do vary by region, bee stock, and season length. Your local association or apiary inspector is the better authority for where you keep bees.
When in the year to treat
The one treatment almost every temperate-climate beekeeper plans around is the late-summer or early-autumn treatment, timed before the colony raises its winter bees. Miss it and a colony that looks strong in September can dwindle and die between December and March.
- Spring: test, and treat only if the count warrants it. Treatment options narrow once supers go on.
- During the honey flow: most products require supers off, so monitoring usually replaces treating here.
- Late summer, after the harvest: the critical window. Supers are off, so the full range of products is available.
- Broodless periods: oxalic acid is most effective when there is little or no capped brood, since mites in sealed cells are shielded from most treatments. In temperate climates that usually means midwinter, and it also applies after a swarm or a split.
Rotating between product families across the year is standard practice to reduce the chance of resistance building in your mite population.
Honey supers and withdrawal periods
The short answer is that most varroa products require honey supers to be removed before treatment, and every product carries a withdrawal period before honey from that hive may be harvested. Amitraz strips and thymol-based products are typically applied with supers off; some formic acid products are labelled for use with supers on. Only the label for the exact product you are holding decides this.
Temperature also constrains the choice. Thymol and formic acid products are temperature-sensitive and carry both a lower and an upper limit, often somewhere in the range of about 10 to 30 C (roughly 50 to 85 F). Treating outside the labelled range risks queen loss, brood damage, or simply a treatment that does not work.
Keeping the schedule straight
A varroa schedule fails on record-keeping more often than on knowledge: a strip that stayed in two weeks too long, a re-treat that was never done, a harvest pulled from a hive that was still inside its withdrawal window. The fix is to write down the product, the start date, and the date it came out, per hive.
Combwise logs treatments per hive and runs an automatic withdrawal-period countdown with a "do not harvest until" date, alongside varroa counts from your inspections. Its Next Actions engine raises a treat-now prompt when a logged mite count crosses your threshold, all computed on-device from your own logs. Recording counts as part of your normal inspection routine is what makes the schedule survive a busy season.
Records, not regulatory advice. This guide is general beekeeping information, not veterinary, regulatory, or professional advice. Always follow the product label, the stated withdrawal period, and the laws that apply to miticide use where you keep bees. A countdown in any app is guidance, not a clearance to harvest.
Related guides
- Hive Inspection Checklist: What to Check and How Often
- Signs of a Queenless Hive: How to Confirm and What to Do
- Combwise: the offline beekeeping logbook
Track treatments and withdrawal dates per hive
Combwise is an offline-first beekeeping app with a treatment and honey-withdrawal tracker, varroa counts in every inspection, and PDF records you own. No account, no cloud.