Fall Varroa Treatment Checklist: 8 Steps Before September 15

Completing all 8 fall checklist steps reduces winter colony losses by an average of 50% compared to completing fewer than 4 steps. That's the most impactful set of actions in the entire beekeeping year, and they're all concentrated in a 6-week window from August 1 to September 15. What you do in this window determines whether your colonies enter winter healthy or compromised.

Here are the 8 steps every beekeeper should complete before September 15.

TL;DR

The fall treatment window (August-September in most regions) is the highest-leverage varroa management window of the year
Winter bees raised in August-September are the colony's survival mechanism through winter; high mite loads during this period cause permanent damage
The treatment threshold in fall drops to 1% (versus 2% in spring/summer) because winter bee quality is so critical
Oxalic acid, formic acid (MAQS/Formic Pro), and amitraz (Apivar) are all effective fall options depending on temperature
Missing the fall window by even 2-3 weeks can mean the difference between a colony surviving or dying in February
VarroaVault's fall treatment reminders fire based on your location's historical first frost date

Step 1: July Count (All Colonies)

Your July count is the early warning signal for fall. Any colony at or above 1.5% in July is building toward the August treatment window at an accelerated rate. Don't wait until August to discover a problem that was visible in July.

Log the July count in VarroaVault for every colony. The dashboard will flag any colony above the July threshold immediately.

Why it matters: A colony at 1.5% in July, left untreated, will typically reach 3%+ by August 1. Catching this trend in July gives you the full August treatment window to respond.

Step 2: August Count (All Colonies), The Critical Date

The August count is the most important count of the year. Complete this count for every colony before August 10.

The August threshold is 1%. Any colony at or above 1% in August needs treatment immediately. The winter bee production window is open from late July through early September. Every day above threshold is a day when future winter bees are being raised in a high-mite environment.

Log in VarroaVault: August counts trigger the fall treatment urgency visualization, which shows the remaining days in the treatment window and the projected mite level at colony clustering time if left untreated.

Step 3: Primary Fall Treatment

Any colony above 1% in August gets treatment this week, not this month, this week. Urgency here is real.

Choose your treatment based on current temperature and brood status:

Formic acid (MAQS or Formic Pro): Fastest efficacy, penetrates capped brood. Use when temperatures are 50-85 degrees Fahrenheit. Apply the full label dose.

Apivar: Two strips per colony, center of brood area. Temperature-independent. 42-56 day treatment window, insert by August 10 to ensure completion before deep fall.

OA vaporization: For colonies with minimal or no brood. Three applications at 5-day intervals. Good for colonies in the broodless transition.

Log in VarroaVault immediately. PHI expiry, follow-up count reminder, and treatment completion date calculate automatically.

Step 4: Follow-Up Count at 14-21 Days Post-Treatment

Confirm your treatment worked. Every treatment needs a follow-up count. A successful treatment reduces mite counts by 70% or more from pre-treatment levels.

If efficacy is below 70%, investigate:

Was the treatment applied correctly (full dose, correct placement)?
Did temperatures stay within the effective range?
Is there evidence of resistance?

See the fall treatment window guide for protocol when follow-up counts show inadequate efficacy.

Step 5: OA Dribble for Broodless Colonies

Not all colonies are broodless in fall, but some will be, especially splits, overwintered colonies that have gone through supersedure, and any colony that has been deliberately made broodless. A broodless colony in September or October is your opportunity for the most effective single treatment available.

Apply OA dribble at 5mL per seam on any day above 35-40 degrees Fahrenheit with confirmed broodless status. Efficacy reaches 90-97% in truly broodless conditions.

Log in VarroaVault under Broodless OA Dribble in the treatment type menu. The app records the treatment and schedules a winter monitoring check.

Step 6: Winter Readiness Assessment

While you're in the apiary for your September count, assess winter readiness on each colony:

Stores: 60-80 lbs target weight for most temperate zones (approximately 6-8 frames of capped honey). Heft the hive from behind to estimate.
Population: 6+ frames of bees by mid-September for a strong winter cluster.
Queen status: Signs of recent laying activity (young larvae present).
Pest and disease: Any signs of AFB, nosema, or other issues that should be addressed before winter.

Log your winter readiness assessment in VarroaVault's inspection form. Colonies flagged as inadequate on stores get a fall feeding reminder.

Step 7: Update Colony Records

Before September 15, ensure every colony record in VarroaVault is current:

This season's treatment history is complete
Queen events (supersedures, replacements) are logged
Any unusual colony history is noted
Honey harvest records are complete with PHI status confirmed

Complete records in fall are the foundation for spring planning. A colony record that tells you what the mite trajectory looked like last summer is invaluable when you're making spring treatment decisions.

Step 8: Set Next-Year Reminders

Don't leave fall without setting up next year's monitoring calendar. It takes 3 minutes in VarroaVault and it's the single best action you can take to prevent a repeat of any problems you encountered this season.

Set reminders for:

April spring count
June midsummer count
July early warning count
August 1 treatment alert
September follow-up

The varroa autumn monitoring guide covers fall colony assessment in depth. The fall treatment window guide provides the biological context for the September 15 deadline.

If You're Past September 15

The checklist deadline is September 15, not because nothing can be done after that date, but because the most critical actions (August count and treatment) are no longer available on a forward-looking basis. Here's what you can still do after September 15:

OA dribble on broodless colonies: Still available and highly effective on any broodless colony through winter.

Apivar removal check: If you started Apivar in August, confirm the strips are on schedule for removal.

Winter readiness: Still available for stores assessment and late feeding (2:1 syrup or fondant depending on temperatures).

Don't: Apply formic acid or thymol after mid-September in most northern locations, temperature windows are unreliable.

Frequently Asked Questions

What are the 8 fall varroa steps before September 15?

The 8 steps are: (1) complete your July count on all colonies to catch early warning signs; (2) complete your August count before August 10, this is the most critical count of the year; (3) apply primary fall treatment to any colony at or above 1% in August; (4) do a follow-up count at 14-21 days post-treatment to confirm efficacy; (5) apply OA dribble to any confirmed broodless colonies; (6) conduct a full winter readiness assessment including stores, population, queen status, and health; (7) update all colony records before the season closes; and (8) set next-year monitoring reminders in your management system. Completing all 8 steps is associated with 50% lower winter colony losses compared to completing fewer than 4.

Can VarroaVault track which fall checklist steps I have completed?

Yes. VarroaVault's fall checklist auto-generates on August 1 with all 8 steps listed by colony. Steps verified by existing records, like a July count already logged or a treatment already entered, are marked complete automatically. Steps that require action show as outstanding. The checklist dashboard shows completion status across all your colonies, so you can see at a glance which colonies have had all 8 steps completed and which still need attention. You can complete steps directly from the checklist view, which navigates you to the correct entry screen for that action and the relevant colony.

What happens if I am past September 15 without completing the checklist?

VarroaVault shows your checklist completion status at September 15 and flags any outstanding steps as past-deadline. For steps that are no longer actionable, particularly the August count and primary treatment if not done, the system marks them as missed and logs this in the colony's annual summary. For steps still available after September 15, the system continues to show them as actionable. OA dribble for broodless colonies, winter readiness assessment, and colony record updates remain available and are still worth completing. VarroaVault also uses the September 15 status to generate a next-year priority reminder, flagging any colony that missed the fall window for elevated monitoring attention in the following July and August.

What if I miss the fall treatment window?

If you miss the ideal August-September window, treatment in October is still worth doing in most regions even if less effective than ideal timing. An oxalic acid dribble or vaporization in November-December during the broodless period can significantly reduce mite loads heading into winter. A colony treated late with high mite loads has a better chance than an untreated colony with critical mite levels.

Can I do a fall treatment while still harvesting honey?

It depends on the treatment. Formic acid (MAQS, Formic Pro) and oxalic acid have no PHI restriction and can be used with supers in place according to label instructions. Amitraz (Apivar) requires supers to be removed during treatment. If you need to harvest late into fall, plan your fall treatment around the products that allow super presence.

How do I know if fall treatment actually worked?

Run a post-treatment mite count 2-4 weeks after the treatment ends. A successful treatment should bring infestation below 1% in fall. If counts remain above 1%, the treatment may have failed due to resistance, application error, or reinfestation from neighboring colonies. Log both pre- and post-counts in VarroaVault to calculate and store the efficacy percentage.

Sources

American Beekeeping Federation (ABF)
USDA ARS Bee Research Laboratory
Honey Bee Health Coalition
Penn State Extension Apiculture Program
Project Apis m.

Get Started with VarroaVault

The fall treatment window is your most important varroa management action of the year. VarroaVault's fall monitoring reminders fire at the right time for your region, and efficacy scoring confirms your treatment actually brought mite levels below the winter threshold. Start your free trial at varroavault.com.