2024 field study: brood interruption and chemical treatments for Tropilaelaps mercedesae
Research update — October 30, 2026. A 2024 peer-reviewed Scientific Reports field study evaluated 51 honey bee colonies in Thailand over 60 days, comparing brood interruption alone, brood interruption combined with oxalic acid, brood interruption combined with formic acid, and untreated colonies.
Reported brood infestation at day 60
| Group | Infested worker brood cells |
|---|---|
| Untreated | 15.25% |
| Brood break only | 0.10% |
| Brood break + oxalic acid | 0.11% |
| Brood break + formic acid | 0% detected |
The untreated colonies began near 0.40% infestation. Although the formic-acid group had no detected infested worker brood cells at day 60, differences among the three brood-break treatments were not statistically significant. Subsequent sticky-board mite detections could represent survivors or reinfestation; zero detected brood infestation is not proof that every mite was killed.
What is a brood break?
A brood break temporarily interrupts egg laying or the availability of developing brood, depriving Tropilaelaps of reproductive sites. Depending on the technique and the presence of drone brood, a complete broodless interval can take roughly three to four weeks. It is not equivalent to a 24-hour treatment.
Why it matters
Tropilaelaps reproduces in developing bee brood and spends comparatively little time on adult bees. The study demonstrates the importance of targeting its reproductive cycle and supports brood interruption as a management approach. It did not test heat treatment.
Heat-treatment research questions
Controlled heat reaching capped brood is a plausible avenue for investigation, but lethal temperature–time combinations for Tropilaelaps, whole-colony effectiveness, and impacts on queens, brood and adult bees require direct study. Findings for Varroa cannot automatically be assigned to Tropilaelaps. No 106°F/24-hour Tropilaelaps eradication claim is established by this study.
Original study: Full peer-reviewed paper, Scientific Reports (2024). See also our Tropilaelaps threat and research hub.