🔬 Quantitative Health Surveillance

About this simulation

Eyeballing a frame for mites catches only the most obvious infestations. Reliable varroa monitoring requires a standardized sample — roughly 300 bees (about half a cup) shaken from a brood-nest frame — processed by an alcohol wash or sugar roll to dislodge phoretic mites so they can be counted against a known denominator.

How it works

• Alcohol wash kills the sample but reliably dislodges nearly every mite present — the gold-standard method.
• Sugar roll coats bees in powdered sugar, making their feet slip so mites fall off; bees survive and are returned to the hive, but recovery is a little less complete.
• The result is expressed as mites per 100 bees, which is compared against a seasonal action threshold (commonly 1–3 in fall, up to 3–6 in summer) to decide whether treatment is warranted.
• After treatment, a follow-up wash verifies efficacy — the percentage reduction in mite load — confirming the product actually worked rather than assuming it did.

Controls

• Sampling method — alcohol wash (lethal) or sugar roll (non-lethal).
• Sample size — number of bees shaken into the sample jar (100–400).
• True colony infestation — the real, hidden mite load per 100 bees; the sample only estimates it.
• Action threshold — the mite-per-100 level above which treatment is recommended.
• Treatment efficacy — expected percentage mite-kill of a chosen treatment, projected as a post-treatment estimate.
• ▶ Run sample — shakes the jar and washes mites through the screen onto the counting tray. Drag to rotate, scroll to zoom.

Did you know?

Because sampling is random, repeated washes of the same colony on the same day rarely give the exact same mite count — the model adds sampling noise around the true infestation rate for exactly this reason, which is why beekeepers are advised to monitor regularly rather than trust a single count.