Varroa Mite Checks: How Often and How to Treat
Varroa mites (Varroa destructor) are the single most serious pest for honey bees in British Columbia. Left unmanaged, they weaken colonies, spread viruses like Deformed Wing Virus, and can lead to colony loss in just a season or two. The good news? With a consistent monitoring and treatment plan, you can keep mite levels low and your bees healthy year-round.
How Often Should You Check for Varroa Mites in BC?
In BC’s climate, we recommend:
Every month from early spring to late fall (March–October)
Four essential checks each year:
Spring buildup (Feb/March)
Mid-summer (June/July – only treat if thresholds are high)
Post-honey harvest (Aug/Sept – prime treatment window)
Before winter (Nov/Dec – broodless period for oxalic acid treatments)
Testing regularly is critical because mite populations can spike quickly, especially in August and September. Always test before and after any treatment to confirm it’s working.
Best Ways to Test
Sugar Roll – Collect ~300 bees from the brood nest, coat in powdered sugar, shake, and count mites.
Alcohol Wash – Same as sugar roll but more accurate; bees are sacrificed.
Sticky Boards – Slide under a screened bottom board for 72 hours to measure natural mite drop.
Aim to keep mite levels below 1–2% in spring and below 3% in summer. Anything higher should be treated right away.
When and How to Treat in BC
February / March – Early Spring
Test as soon as weather is consistently above 8–10°C.
If levels are high, use Formic Pro or Api-Life Var before honey supers go on.
Begin drone brood removal as colonies build.
June / July – Mid-Summer
Test every 3–4 weeks.
Only treat if above threshold; Formic Pro can be used if needed.
Avoid Apivar unless honey supers are off.
August / September – Post-Honey Flow
This is the most important treatment window in BC.
Treat immediately after removing honey supers.
Options: Apivar, Formic Pro, Api-Life Var, Thymovar, HopGuard III.
Combine weak colonies before cold weather sets in.
November / December – Winter Broodless Period
Test to confirm mites are still present.
Apply Oxalic Acid vaporization or drizzle for a final knockdown.
Works best when no brood is present.
Integrated Pest Management (IPM) for BC Beekeepers
Rotate treatments to prevent resistance (don’t use the same product season after season).
Pair chemical treatments with cultural controls: screened bottom boards, hygienic queens, and drone brood removal.
Record every test and treatment to spot trends over time.
Need a Ready-Made BC Varroa Plan?
To make this easier, we’ve created the Varroa Mite Chart PDF — a complete BC-specific, season-by-season mite management guide. It includes:
Treatment timing for all four seasons
Product-specific instructions
Mite biology overview
Printable mite tracking sheet
It’s designed so you can open it, follow it, and keep your colonies healthy without second-guessing your timing. Click here for more info.