Honey Bee Acarine Disease (Tracheal Mite Infestation): Symptoms, Diagnosis, and Hive Impact

Quick Answer
  • Honey bee acarine disease is caused by the internal tracheal mite Acarapis woodi, which lives in the breathing tubes of adult bees rather than on the outside of the body.
  • There is no single telltale sign. Beekeepers may notice crawling bees, poor flight, disjointed or K-wing posture, weak wintering, and gradual colony decline.
  • A true diagnosis requires microscopic examination of adult bee tracheae. Visual signs alone are not enough because other hive problems can look similar.
  • Hive impact ranges from mild stress to reduced overwinter survival, especially when colonies are already weakened by poor nutrition, weather stress, or other parasites.
  • Typical U.S. cost range for evaluation and mite confirmation is about $25-$75 for state apiary or extension lab submission, or roughly $100-$300 if a beekeeper also purchases sampling supplies, replacement queen, and supportive management steps.
Estimated cost: $25–$300

What Is Honey Bee Acarine Disease (Tracheal Mite Infestation)?

Honey bee acarine disease is an infestation of the adult bee's breathing tubes, or tracheae, by the mite Acarapis woodi. Unlike Varroa mites, these mites are not usually seen on the outside of the bee. They live inside the thoracic tracheae, where they feed and reproduce, which can interfere with normal breathing and flight.

This condition affects adult honey bees only. Queens, workers, and drones can all help spread mites from bee to bee within a colony, and movement of package bees, queens, or whole colonies can spread infestation between apiaries. Detection tends to be easier in fall and winter, when infestation rates are often higher and weak colonies are more noticeable.

Acarine disease does not always cause dramatic signs. Some colonies show only subtle weakness, while others struggle with flight, winter survival, or overall productivity. Because the signs overlap with other bee health problems, confirmation usually depends on lab-style examination rather than appearance alone.

Symptoms of Honey Bee Acarine Disease (Tracheal Mite Infestation)

  • Crawling bees near the hive entrance
  • Poor flight or inability to take off
  • Disjointed or K-wing posture
  • Distended abdomen
  • Weak winter cluster or poor overwinter survival
  • Gradual colony decline

There is no single symptom that proves tracheal mites are present. A colony can have crawling bees, wing changes, or weak wintering and still be dealing with something else, such as Varroa pressure, viral disease, queen failure, pesticide exposure, or nutrition problems.

When to worry: take action if you see repeated flight problems, many crawling bees, or a colony that is fading without a clear reason. Because visual signs are unreliable, the next step is usually to collect the right adult bees and work with your state apiary inspector, extension service, or bee lab for confirmation.

What Causes Honey Bee Acarine Disease (Tracheal Mite Infestation)?

Acarine disease is caused by infestation with Acarapis woodi, a microscopic mite that lives inside the tracheae of adult honey bees. The mites move from bee to bee through close contact inside the colony. Queens, workers, and drones can all contribute to spread, and moving package bees, queens, or established colonies can introduce mites into new locations.

The disease tends to matter most when colonies are under multiple stresses at once. Cold weather, poor nutrition, weak colony population, and other parasites or infections can make the effects of tracheal mites more noticeable. In practical terms, mites may be part of a larger hive-health picture rather than the only problem.

Season also matters. Infestation levels often become easier to detect in fall and winter, while signs may be less obvious during periods of peak bee population. That is one reason some colonies seem to decline during overwintering even when the problem was building earlier.

How Is Honey Bee Acarine Disease (Tracheal Mite Infestation) Diagnosed?

A true diagnosis requires microscopic examination of the tracheae from adult bees. Visual inspection of the hive is not enough. Even classic signs like crawling bees or disjointed wings are not specific, and some infested bees show few outward changes.

For the best chance of finding mites, samples are usually taken from moribund older bees near the hive entrance or from bees entering and leaving the hive. USDA guidance notes that detection is often highest in fall and winter. Freshly collected bees are typically preserved promptly in alcohol before dissection and examination.

During examination, the tracheae may show darkening, blotches, crust-like lesions, or obstruction in heavier infestations. Still, discoloration alone does not confirm mites, and normal-looking tracheae do not fully rule them out. Your vet may work alongside an apiary inspector, extension specialist, or diagnostic lab to interpret results and decide whether treatment or broader hive management changes make sense.

Treatment Options for Honey Bee Acarine Disease (Tracheal Mite Infestation)

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$25–$120
Best for: Beekeepers managing a small apiary, mild suspected disease, or colonies needing supportive care while awaiting confirmation
  • Confirm suspicion with extension or state apiary inspection before treating
  • Improve colony support: adequate feed stores, reduced stress, dry/well-ventilated winter setup
  • Replace failing queen if colony is weak and poorly organized
  • Avoid unnecessary chemical use if infestation is not confirmed or colony is already collapsing
Expected outcome: Fair when infestation is low and colony strength is otherwise good. Supportive management may reduce losses, but it may not clear a meaningful infestation on its own.
Consider: Lowest upfront cost, but slower and less targeted. If mites are significant, supportive care alone may not prevent winter decline.
Most Common

Recommended Standard Treatment

$40–$180
Best for: Most manageable colonies with confirmed or strongly suspected tracheal mite infestation
  • Microscopic confirmation or strong field suspicion based on colony history
  • Seasonally appropriate labeled tracheal-mite treatment such as menthol, formic acid, or thymol-based products where legal and label-appropriate
  • Late summer or autumn timing when treatment is most often recommended
  • Follow-up colony assessment and routine management to reduce additional stressors
Expected outcome: Good to fair depending on colony strength, season, and whether other problems like Varroa, viruses, or poor nutrition are also present.
Consider: More targeted than supportive care, but treatment choice depends on temperature, honey flow timing, product label restrictions, and local regulations. Chemical handling and timing matter.

Advanced / Critical Care

$150–$450
Best for: Complex apiaries, repeated winter losses, or pet parents wanting every available management option for valuable colonies
  • Full hive-health workup to look for concurrent issues such as Varroa, Nosema/Vairimorpha, queen failure, starvation, or pesticide stress
  • Queen replacement with resistant or better-performing stock
  • Combining or restructuring weak colonies when appropriate
  • Repeated monitoring, lab submissions, and apiary-wide management planning for multiple affected hives
Expected outcome: Variable. Outcomes improve when tracheal mites are addressed as part of a broader colony-health plan rather than treated in isolation.
Consider: Highest cost and labor. Best for situations where one diagnosis is unlikely to explain the whole hive problem.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Honey Bee Acarine Disease (Tracheal Mite Infestation)

Bring these questions to your vet appointment to get the most out of your visit.

  1. Do these signs fit tracheal mites, or should we also rule out Varroa, viral disease, queen problems, or nutrition stress?
  2. Which adult bees should I collect for the most accurate tracheal mite testing?
  3. Is this the right season to test, or should we repeat sampling in fall or winter if results are unclear?
  4. What infestation level would make active treatment reasonable in my colony or apiary?
  5. Which labeled treatment options are practical for my climate, honey flow timing, and hive setup?
  6. Should I requeen this colony, and would more resistant stock help long term?
  7. How should I support the colony during treatment so stress stays as low as possible?
  8. If one hive is positive, should I monitor or manage nearby colonies differently?

How to Prevent Honey Bee Acarine Disease (Tracheal Mite Infestation)

Prevention starts with strong colony management. Healthy, well-fed colonies handle stress better than weak ones, and extension guidance consistently emphasizes reducing stress as a practical way to limit disease impact. Good nutrition, appropriate population size going into winter, and avoiding unnecessary disturbance all matter.

It also helps to be thoughtful about bee movement and replacement stock. Introducing queens, package bees, or colonies from outside sources can move mites between apiaries. When possible, use reputable sources, monitor new additions closely, and avoid sharing equipment in ways that could spread pests or disease pressure.

Routine monitoring is important even though tracheal mites are less common than they once were. If a colony shows unexplained crawling bees, poor flight, or winter decline, collect the right adult bees and seek confirmation rather than guessing. In some operations, selecting or requeening with more tolerant stock may also support long-term control.

Because treatment timing and product choice depend on season, honey flow, and local rules, prevention plans should be tailored with your vet, extension beekeeper program, or apiary inspector. The goal is not one perfect answer. It is a practical plan that fits your bees, your region, and your management style.

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