Spring Varroa Check: Monitor Now, Plan Treatment Before Mites Peak

May can fool beekeepers. Colonies may look beautiful: big brood nests, fresh wax, and busy entrances. Varroa mites are building at the same time, mostly hidden under capped brood.

A spring mite check gives you time to make a calm plan instead of discovering a problem in late summer when winter bees are already being raised.

Monitor, do not guess

Visual signs are not enough. A colony can look strong and still carry a damaging mite load.

Use a standard mite count method. The most common field method is an alcohol wash. A sugar roll can also be used, but it is generally more variable. Sticky boards are useful for trends, but they are not as reliable for treatment decisions.

For an alcohol wash:

1. Choose a brood frame with nurse bees.
2. Confirm the queen is not on that frame.
3. Collect about 1/2 cup of bees, roughly 300 bees.
4. Wash the sample and count the mites.
5. Divide the mite count by 3 to estimate mites per 100 bees.

Example: 9 mites from a 300-bee sample equals about 3 mites per 100 bees, or a 3% infestation.

Use spring thresholds conservatively

The Honey Bee Health Coalition's Tools for Varroa Management names 3 mites per 100 bees (3%) as the action threshold across most of the year, tightening to about 2% heading into fall. In spring, many beekeepers act earlier — closer to 2% — because mite populations can climb fast as brood production expands. We recommend the same conservative spring approach below.

A practical approach:

• 0-1 mite per 100 bees: keep monitoring monthly
• Around 2 mites per 100 bees: plan your next move; do not ignore it
• 3 or more mites per 100 bees: treatment or another effective control is usually warranted

Local conditions matter. Colonies near collapsing hives, feral colonies, or yards with a history of high mites may rebound faster.

Plan around honey supers and temperature

Before choosing a treatment, check three things:

• Are honey supers on?
• What are the expected daytime highs and lows?
• Is the colony strong enough for that product?

Always follow the current label for the product you use. Some treatments cannot be used with honey supers intended for harvest. Some have strict temperature ranges. Some may increase queen risk or brood interruption if used during stressful weather.

Formic acid products are notable because some are labeled for use with honey supers under specific conditions, but they also have temperature and colony-strength limits. Oxalic acid is most effective when little or no capped brood is present, so it may not be enough by itself in a booming May brood nest unless used according to an appropriate labeled method.

Other registered miticide categories include thymol-based products (e.g., Apiguard — temperature-sensitive, supers off) and hop-beta-acids (e.g., HopGuard — usable with supers under label conditions). Each has its own temperature, brood-state, and super-compatibility rules. Read the current label for whichever product you choose.

Do not mix treatments, improvise dosages, or use off-label applications.

Consider non-chemical tools as part of IPM

Cultural controls can help slow mite growth, but they do not replace monitoring.

Options include:

• Brood breaks through splits
• Removing capped drone brood if you are already managing drone frames
• Requeening with stock selected for mite resistance
• Avoiding the exchange of brood frames from high-mite colonies into low-mite colonies

A swarm-control split may temporarily reduce mite reproduction by interrupting brood, but you should still test both resulting colonies.

Recheck after action

A treatment plan is not finished when the product goes in.

Record:

• Pre-treatment mite count
• Product or control method used
• Date applied
• Weather conditions
• Whether supers were present
• Follow-up count

Recheck according to the product label or once the treatment window has passed. If mite levels remain high, get advice from a local experienced beekeeper or extension resource before stacking additional treatments.

When to act

Act now if:

• You have not taken a mite count yet this spring
• A colony tests around 2-3 mites per 100 bees or higher
• You plan to add honey supers soon and need to know your options
• A colony came through winter weak, spotty, or with mite history
• Nearby colonies have crashed or are being robbed

Monitor instead of treating if:

• Your mite count is low
• The colony is growing well
• You have a clear date for the next mite check
• You are using brood breaks or splits and will verify results with another count

Bottom line

May mite monitoring is not busywork. It protects the bees that will raise your summer workforce and, later, your winter bees. Count now, choose carefully, and write it down.