Most Australian beekeepers have spent the past few years learning a lot more about mites than most of us ever wanted to know.
Varroa has understandably received most of the attention. But there is another parasitic mite that Australian beekeepers should have on their radar: Tropilaelaps mercedesae, commonly shortened to Tropi.
Tropi is tiny, fast-moving and heavily dependent on honey bee brood. Overseas, it can cause serious damage to Apis mellifera colonies, and its changing geographical distribution has increased international concern about the pest.
The good news is that Tropilaelaps mites are regarded as exotic to Australia. Australian biosecurity authorities list Tropilaelaps mercedesae and Tropilaelaps clareae among exotic mites of concern.
That doesn't mean Australian beekeepers need to panic.
It does mean we should know what we're looking for.
And interestingly, recent overseas research has produced encouraging results involving formic acid, including the commercial treatment Formic Pro.
So, what exactly is Tropi, why are researchers taking it seriously, and what might the latest research mean for Formic Pro Australia and the future use of formic acid Australia?
Let's take a closer look.
What Is Tropilaelaps mercedesae?
Tropilaelaps mercedesae is an external parasitic mite of honey bees.
At roughly 1 mm long, Tropilaelaps mites are small reddish-brown mites. Unlike Varroa, which can spend considerable time on adult bees, Tropi is particularly dependent on developing brood.
Female mites enter brood cells before they are capped. Once inside, they reproduce and feed on developing bees.
The resulting damage can include unhealthy brood, reduced adult bee longevity and deformities in emerging bees.
Signs associated with Tropilaelaps infestation can include:
- irregular or patchy brood patterns
- damaged or dead brood
- bees emerging with deformed wings, legs or abdomens
- weakened colonies
- reddish-brown mites moving rapidly across brood comb.
One reason Tropi deserves attention is how quickly populations can increase when plenty of brood is available.
Tropi vs Varroa: What's the Difference?
It's tempting to think of Tropi as simply another Varroa mite.
There are similarities, but their biology isn't identical.
Both parasites reproduce in capped honey bee brood and both can seriously compromise colony health. However, Tropilaelaps is much more dependent on brood.
That weakness is extremely important.
Because Tropi needs developing brood to reproduce successfully, interrupting the colony's brood cycle can disrupt the mite's life cycle.
This has led researchers to investigate integrated approaches combining brood breaks with mite treatments.
And the results are worth paying attention to.
What Does the Latest Research Tell Us?
A 2024 study published in Scientific Reports investigated the management of Tropilaelaps mercedesae using brood interruption alone and brood interruption combined with formic or oxalic acid treatments.
The difference between treated and untreated colonies was striking.
Over 60 days, worker-brood infestation in untreated colonies increased from 0.4% to 15.25%. The treatment groups remained below 0.11% at Day 60.
Importantly, however, the researchers cautioned that the treatments did not necessarily eradicate every mite.
That's an important distinction.
Successful mite management isn't always about finding a single silver bullet. Monitoring, treatment timing, brood management and follow-up checks all matter.
What About Formic Pro and Tropi?
This is where things become particularly interesting for Australian beekeepers already familiar with Formic Pro Australia as a Varroa treatment.
A 2026 study published in Veterinary Parasitology investigated formic-acid-based treatments against both Tropilaelaps mercedesae and Varroa destructor in western Georgia.
Researchers evaluated Formic Pro and another formic-acid treatment during late summer and autumn.
They reported rapid, near-complete mortality of Tropilaelaps in both seasons and reductions in brood infestation to near-zero levels.
Tropilaelaps was also more consistently susceptible to the treatments than Varroa in the study.
That doesn't mean Australian beekeepers should start treating hives for Tropi.
Quite the opposite.
Tropilaelaps is an exotic pest in Australia, and a suspected detection is a biosecurity matter — not a cue for DIY treatment.
But the research is encouraging because it gives the international beekeeping community another potential tool for managing the parasite where it is present.
Why Is Formic Acid Interesting?
Anyone researching formic acid Australia for beekeeping will quickly discover that it behaves differently from many contact miticides.
Formic acid works through vapour inside the hive.
One particularly useful characteristic in mite management is its ability to affect mites associated with capped brood.
That's significant because the capped cell provides mites with a protected reproductive environment where some other treatments have limited effect.
Research conducted in Thailand has also reported substantial reductions in Tropi and Varroa following applications of Formic Pro and liquid formic acid.
But there is an equally important part of the story: formic acid isn't something to improvise with.
Temperature, concentration, application method, colony condition and exposure all matter.
Formic Pro Australia: Temperature Matters
Formic acid is powerful, and that means it needs to be respected.
Australian conditions can create particular challenges because hive temperatures can climb quickly.
Australian permit directions for Formic Pro have specified a daytime-high treatment window and warned that high temperatures during the initial treatment period may result in excessive losses of bees, brood or queens.
Research into Tropilaelaps management has raised similar concerns. One study reported reduced adult bee populations in colonies exposed to a brood break plus formic acid when temperatures regularly exceeded 30°C.
The practical lesson is simple:
More treatment isn't better treatment. Correct treatment is better treatment.
Always follow the current Australian product label, APVMA registration or permit conditions applicable to the product, pest, location and circumstances.
Never assume that an overseas research protocol is automatically legal or appropriate for an Australian apiary.
Could Tropi Reach Australia?
Australia's biosecurity system treats Tropilaelaps seriously for a reason.
The Australian Government lists Tropilaelaps mercedesae among mites of bees considered national priority plant pests.
Tropilaelaps mites occur in parts of Asia and nearby regions, and movement of infested bees creates a potential pathway for spread.
Australian beekeepers therefore form an important part of the country's early-detection network.
You don't need to become a mite taxonomist.
You simply need to know what normal looks like in your colonies — and recognise when something doesn't look right.
How Can Australian Beekeepers Look for Tropi?
Regular brood inspections are useful.
Look for unusual brood patterns, damaged pupae, unexplained deformities and small reddish-brown mites.
Brood uncapping can also help detect mites associated with developing bees.
Alcohol washing, already familiar to many beekeepers as a Varroa-monitoring technique, can detect Tropilaelaps mites as well.
Remember that visual identification isn't enough for a definitive diagnosis. Small mites and other hive organisms can easily be confused with one another.
If you find something suspicious, don't simply assume it's Varroa.
What Should I Do If I Suspect Tropilaelaps?
Treat a suspected Tropilaelaps detection as a biosecurity issue.
Avoid moving affected hives, bees, brood or equipment unnecessarily, and contact the relevant Australian biosecurity authority.
The national Exotic Plant Pest Hotline is 1800 084 881.
Early reporting matters.
Trying to quietly treat a suspicious colony could potentially make an incursion more difficult to trace and manage.
Where Does Formic Pro Fit Into Australian Beekeeping?
For Australian beekeepers, Formic Pro is currently relevant primarily in the context of Varroa management, subject to current Australian regulatory requirements.
Buzzbee stocks Formic Pro alongside other Varroa monitoring and management equipment.
Recent Tropilaelaps research adds another fascinating chapter to the formic-acid story, but it should not be interpreted as an Australian recommendation to treat Tropi independently.
If Tropi were ever detected here, control measures would be determined by biosecurity authorities and the applicable regulatory framework at that time.
For now, our best defence is awareness.
Know your bees.
Know your brood.
Monitor mites.
And report anything unusual.
Frequently Asked Questions
Is Tropilaelaps mercedesae currently in Australia?
Tropilaelaps mites are regarded as exotic pests of Australia. Tropilaelaps mercedesae is included among Australia's priority exotic bee mites.
Is Tropi worse than Varroa?
Both can cause serious colony damage, but their biology differs. Tropilaelaps reproduces rapidly when brood is continuously available and is particularly dependent on developing honey bee brood. Rather than thinking of one as simply "worse", beekeepers should understand that they require appropriate monitoring and management strategies.
Can Formic Pro kill Tropilaelaps mites?
Overseas research has shown very strong results. A 2026 study found Formic Pro produced rapid, near-complete mortality of T. mercedesae under the trial conditions. This research does not constitute an Australian label direction or recommendation for Tropilaelaps treatment.
Is Formic Pro available in Australia?
Formic Pro has been available to Australian beekeepers for Varroa management under Australian regulatory arrangements. Because registrations, permits and conditions can change, check the current APVMA requirements before use.
Is formic acid safe for honey bees?
Formic acid can be used effectively when an approved product is applied correctly, but temperature, dose and colony conditions matter. Excessive exposure or inappropriate environmental conditions can harm adult bees, brood and queens. Always follow the current Australian label or permit.
Can I make my own formic acid treatment?
Beekeepers should use treatments legally authorised for their circumstances and follow Australian label and permit requirements. Don't assume that recipes, concentrations or application methods described overseas are legal or safe for Australian hives.
How do I test for Tropi?
Brood inspection and uncapping can reveal suspicious mites. Alcohol washing can also detect Tropilaelaps. Suspected detections should be professionally confirmed rather than diagnosed solely by appearance.
What should I do if I find a mite that looks like Tropilaelaps?
Don't move potentially affected bees or equipment unnecessarily. Photograph or retain a sample if this can be done safely, and contact the Exotic Plant Pest Hotline on 1800 084 881 for advice.
Where can I learn more about Formic Pro Australia?
Visit Buzzbee's Varroa treatment range for information on Formic Pro Australia, mite-monitoring equipment and other products used by Australian beekeepers. Always check the current product directions and APVMA requirements before treating colonies.