Late-Summer Varroa Mite Check: What Your Count Needs to Tell You
Late summer is a time to get a measured Varroa result, not guess from how busy the entrance looks.
In many U.S. regions, this means sampling after the main honey supers come off and before or during the period when colonies begin raising longer-lived winter bees. The exact week varies with climate, forage, and colony condition.
Your mite count should answer three questions:
- What is the colony’s current mite level?
- Has that level changed since the previous sample?
- Does it require action under current local guidance?
The count is only useful when you record the method, sample size, colony, and date, and when you check again after any management step.
Why late summer matters
A colony can look large and productive while its Varroa pressure is increasing.
As the season advances, adult-bee and brood populations may begin declining while mites remain in the colony. That can increase the number of mites relative to the available bees.
The timing also matters because colonies in colder regions begin producing the bees that must live through winter during late summer and early fall. Penn State explains that winter bees can live far longer than summer workers and depend on good nutrition and lower disease pressure. See Penn State’s seasonal-management guidance.
This does not mean every U.S. beekeeper should test on the same August date. A colony in northern Pennsylvania, coastal Florida, or the Mississippi Delta may be following a different seasonal schedule.
The important point is to identify your local post-flow and winter-preparation window before it passes.
A strong-looking hive is not a mite test
Heavy entrance traffic, boxes full of bees, and a good honey crop do not establish a low mite level.
Varroa mites reproduce under capped brood. They can build inside a colony before the beekeeper sees obvious adult-bee symptoms. The University of Minnesota Bee Lab recommends regular sampling because visual inspection alone does not provide a dependable mite percentage. Review its Varroa testing guidance.
This is why “I did not see any mites” is not a useful inspection record.
July 29. Alcohol wash. Approximately 300 adult bees. Six mites. Estimated result: 2 mites per 100 bees.
That result can be compared with the same colony’s previous and later samples.
What a good sample must tell you
The result should be tied to one named colony.
Small apiaries should not assume that the strongest hive represents every nuc and colony in the yard. Mite levels can differ between neighboring colonies because of brood patterns, queen history, robbing, drifting, previous management, and colony strength.
Record:
- Colony ID
- Sampling method
- Approximate number of adult bees
- Mites counted
- Mites per 100 bees
- Date and weather
- Brood condition
- Whether honey supers are present
- Previous result
- Next sample date
Without those details, the number becomes difficult to interpret later.
Alcohol wash, soap wash, or sugar roll?
Several sampling methods are used, but they are not equally dependable.
The University of Minnesota describes the alcohol wash as faster and more reliable than the powdered-sugar roll for estimating mites on adult bees. The alcohol wash kills the sampled bees, which should be stated honestly. Many established protocols use roughly 300 adult bees, often described as about half a cup, from the brood area. The queen must not be included in the sample.
A soap wash follows a similar counting principle with a different liquid. A sugar roll does not intentionally kill the sampled bees, but technique, humidity, and incomplete mite removal can reduce its reliability.
A beekeeper who has never taken a sample should learn the procedure from a current extension demonstration, inspector, mentor, or bee-club workshop. A written article is not the best place to learn safe queen exclusion and sample handling for the first time.
Whichever accepted method you use, consistency matters. Changing methods and sample sizes makes comparisons more difficult.
Turn the count into a percentage
The common comparison is mites per 100 adult bees.
Mites counted ÷ estimated bees sampled × 100
For a 300-bee sample:
| Mites found | Approximate result |
|---|---|
| 3 | 1 mite per 100 bees |
| 6 | 2 mites per 100 bees |
| 9 | 3 mites per 100 bees |
These examples explain the arithmetic. They are not universal treatment instructions.
There is no single national action number
Published action thresholds vary by region, season, colony condition, and extension program.
Virus pressure, brood amount, climate, management history, and the time remaining before winter can all affect risk. A result that prompts one state program to recommend action may be interpreted differently elsewhere.
Use a current source from your state extension program, state apiary inspector, university bee lab, or the Honey Bee Health Coalition. When a registered control is being considered, follow the current product label and state regulations.
The Honey Bee Health Coalition released the ninth edition of Tools for Varroa Management on June 22, 2026. It updates monitoring and management information, but it does not remove the need for state-specific guidance and label compliance. See the coalition’s current updates.
Late-summer mite-record checklist
The sample
- Colony name or number
- Date
- Method
- Estimated sample size
- Mites counted
- Calculated percentage
The colony
- Recent queen evidence
- Brood amount and stage
- Adult-bee population
- Food stores
- Signs of disease or unusual decline
- Recent robbing or drifting pressure
The management limits
- Honey supers present or removed
- Current and forecast temperature
- Local action guidance
- Registered product label, when relevant
- Brood-dependent limitations
- Required follow-up or retest date
The July hive-inspection checklist can help organize the broader colony observations around the sample. When entrance activity is confusing, compare it with the signs in Robbing Bees or Orientation Flights?
A practical decision guide
The result is below the local action point and stable
Record it and schedule the next sample.
Do not turn one low count into permission to stop monitoring for the season. Sampling can underestimate the true population, and mite pressure can change through drifting, robbing, and continued reproduction.
The result is close to the local action point, rising, or uncertain
Shorten the follow-up interval.
Check whether the sample was large enough and whether the method was performed consistently. Compare the result with previous records and ask a local extension specialist or mentor how it fits current regional conditions.
The result is above the current local action point
Respond promptly using current extension guidance, the registered label, and the colony’s actual conditions.
Temperature, capped brood, honey supers, and product registration can determine whether a particular option is permitted or likely to work. Do not select a control from an old social-media comment or a general blog post.
The colony is declining regardless of the number
A mite result is one part of the diagnosis.
Queen problems, disease, food shortage, robbing, pesticide exposure, and secondary pests may also be involved. Contact an inspector or qualified local resource when the colony’s condition is unclear.
Retest after the management step
Do not assume that an action worked because it was completed.
Temperature, brood conditions, application error, resistance, reinvasion, and colony differences can all affect the result. Follow-up sampling lets the beekeeper verify the outcome instead of relying on the management date alone.
Your record should contain:
- Result before action
- Action and date
- Conditions during use
- Follow-up sample date
- Follow-up result
That sequence turns a treatment entry into useful evidence.
Let local seasonality set the date
Mississippi State’s beekeeping calendar describes July and August as a summer-dearth and post-harvest period when sampling can guide Varroa decisions before winter-bee production. Read the Mississippi calendar.
UF/IFAS guidance published July 16, 2026, similarly tells Florida Panhandle beekeepers to shift attention toward pest management as the main flow ends. Read the post-flow guidance.
In the Northeast, Penn State places winter-bee production later in summer and early fall.
These are regional examples, not one national calendar. Use local bloom, weather, colony records, and extension guidance to identify your window.
The habit behind “Mite Count First”
Good hive decisions begin with knowing what is happening inside the colony.
The Mite Count First Vintage Cap recognizes the beekeeper who would rather record a real result than choose the next step from appearance or guesswork. It is a washed cotton-twill cap made around a colony-care habit another active beekeeper will understand.
Sources and further reading
- University of Minnesota Bee Lab: Varroa Mite Testing and Management
- Penn State Extension: Honey Bee Management Throughout the Seasons
- Honey Bee Health Coalition updates
- Mississippi State University Extension: Beekeeping Calendar
- UF/IFAS: As the Main Honey Flow Winds Down
This article provides general educational information. Varroa thresholds, registered products, temperature limits, honey-super restrictions, and management recommendations vary by state and colony. Follow current labels and consult a local extension office, state apiary inspector, university bee program, or qualified mentor.