Varroa mite drop counter from a bottom board photo
Upload a photo of your sticky board — the QueenRadar model marks everyVarroa destructor mite, counts them and computes the daily mite fall. No tally counter, no magnifier, no sign-up.
The counter runs on this page — the photo is analyzed on our server. The result is indicative — base treatment decisions on the guidance for your region and season.
Varroa mite fall — how to measure and interpret it
Natural mite fall is the number of varroa mites that drop off the bees onto the bottom board within 24 hours. It is the simplest, non-invasive way to monitor colony infestation: no bee sampling, no alcohol wash. All you need is a screened bottom board, a light sticky board and 1–3 days.
Indicative daily drop thresholds
| Mites / day | Level | Action |
|---|---|---|
| < 1 | low | monitor, repeat in 1–2 weeks |
| 1 – 3 | moderate | confirm with alcohol wash / sugar roll, plan treatment |
| > 3 | high | treat according to your regional programme |
The thresholds apply to the active season (spring–summer). In late summer and autumn, when the colony shrinks, the same drop means a higher infestation — even 1–2 mites per day call for action. After a treatment (oxalic acid, formic acid, amitraz) the drop is many times higher and is used to evaluate efficacy, not infestation.
How the counter works
The photo is split into tiles; each tile is analyzed by a neural network (YOLO) trained on thousands of labelled mites from real boards — with wax, pollen and other debris. Detections are merged into one result; the confidence slider tightens or relaxes the count, and the dot overlay lets you verify every mark.
Other ways to assess infestation
Mite drop shows the trend but does not tell you directly what share of bees is infested. When the result is borderline or you need a quick decision, use a sample-based method:
- Sugar roll. About 300 bees (half a cup) from a brood frame go into a jar with a mesh lid; add a spoonful of icing sugar, roll and shake the mites out onto a light surface. The bees survive and go back to the hive. Good for regular checks during the season.
- Alcohol wash. The same bee sample rinsed in alcohol or washer fluid. It gives the most accurate infestation percentage, but the sampled bees die. Use it to confirm a result before treatment.
- Drone brood check. Pull drone pupae with an uncapping fork and count mites on their pale bodies. A quick look in spring and early summer, when varroa prefers drone brood; of little use outside that period.
In practice: mite drop every few weeks as ongoing monitoring, a sugar roll or alcohol wash when the drop rises or before deciding on treatment, drone brood as a quick spring check.
Mite drop after treatment
After applying a treatment, insert a clean board and count the drop every 1–3 days, replacing the board after each photo. A high drop in the first days followed by a clear decline means the treatment is working. If the drop stays high long after the treatment has ended, the colony may have been reinvaded by mites from nearby apiaries or the treatment failed — check infestation with a sample-based method. Photos of successive boards uploaded to the counter give a simple record of the treatment.
While you are in the hive, check that the colony has a laying queen — see our guide onhow to find the queen bee, and you can check a comb photo with the QueenRadar model tester.
Frequently asked questions
How do I count varroa mite drop on a bottom board?+
Slide a clean, light-coloured sticky board (lightly oiled or coated with petroleum jelly so the mites cannot walk away) under the screened bottom board for 1–3 days. Take it out, photograph the whole board from above in good light and upload it here. The counter marks the mites and divides the total by the number of days.
What daily varroa mite drop is dangerous?+
Thresholds are indicative and depend on the season. For natural mite fall the usual rule of thumb is: below 1 mite per day — low infestation; 1–3 per day (spring–summer) — moderate, confirm with an alcohol wash or sugar roll; above 3 per day — high, treatment advised. In autumn, when the colony shrinks, the same numbers mean a higher infestation.
What is the difference between natural mite fall and post-treatment drop?+
Natural mite fall counts mites that fell off on their own and shows the infestation trend. The drop after a treatment (oxalic acid, amitraz…) is many times higher and is used to judge the efficacy of the treatment. The counter works for both, but apply the thresholds only to natural fall.
Does the counter tell mites apart from wax crumbs and pollen?+
The model was trained on photos of real boards with debris (wax, pollen, bee legs), so in most cases yes. On a very dirty board raise the confidence threshold or brush the board gently before the photo. Check the marks in the preview — you make the final call.
How do I take a good photo of the board?+
Whole board in frame, from above, without shadows or glare; daylight in the shade gives the best contrast. Higher resolution is better — a 12 MP phone photo is enough. Do not downscale before uploading (messengers compress photos — send the original).
Is my photo stored?+
No. The photo is analyzed on our server and immediately discarded from memory. We keep it only if you explicitly tick the consent to donate it for model training.
Training data sources
The mite-drop model was trained on QueenRadar's own photos and on open datasets released under CC BY 4.0: J. Divasón et al., Dataset for varroa mite detection on sticky boards (Zenodo, 2023; paper: Agriculture 2025, 15(9), 969) and the “varroa” dataset by user tomislav-uri (Roboflow Universe, 2022). Thank you.
Looking for the queen in the apiary?
The QueenRadar app detects the queen and queen cells on the comb live — offline, on your phone.
Updated: 26 September 2026