Learning Objectives
- Measure mite pressure with a consistent method and record the result.
- Interpret counts with brood, season and colony condition rather than one universal threshold.
- Use splits, brood breaks and drone-comb management deliberately, then recheck.
- Recognize when to seek prompt local advice rather than allow avoidable collapse.
Field infographic
Measure, interpret, recheck
A count is evidence, not an automatic diagnosis or universal treatment threshold.
- 1
Sample
Use a consistent method; protect the queen and record sample size.
- 2
Calculate
Mites divided by sampled bees, multiplied by 100.
- 3
Context
Consider brood, season, symptoms and colony strength.
- 4
Act
Use responsible management and current local guidance when needed.
- 5
Recheck
Verify the trend; do not assume a split or propolis solved it.
Local survivor selection needs monitoring. Propolis is not Varroa control.
Diagram
Development times by caste
The clock behind grafting calendars, mite trapping and queenless triage. Click any band for stage detail.
Queen
16 days
Graft day 0 → capped day 5 → move cells day 10 → emerge day 12 → mating flights from day 17 → laying day 21–24.
Worker
21 days
Varroa prefer the 12-day capped stage; the 24-hour graft window and the 9-day post-capping mite cycle both key off it.
Drone
24 days
Longest capped stage means highest mite preference — the basis of drone-brood trapping and of drone saturation in a closed mating population.
Adult worker task progression
Day 1–3
Cell cleaning; hypopharyngeal glands not yet active.
Day 3–12
Nurse bee — glands at peak, feeds larvae and the queen.
Day 12–18
Wax production and comb building; receives and ripens nectar.
Day 18–21
Guard duty; Koschevnikov alarm pheromone response peaks.
Day 21–42
Forager — flight muscle and behaviour shifted by juvenile hormone.
Winter bees
Task progression suspended; high vitellogenin, 4–6 month lifespan.
Count backwards from what you see: eggs mean the queen laid within 3 days; capped worker brood means she was laying at least 9 days ago.
Read these first
This chapter assumes the ground covered below. If any of it is unfamiliar, take the detour — the sequence exists so nothing here has to be taken on faith.
Reading mode
Treatment-free is a breeding and management commitment, not a promise to ignore mites. Mark's 4H standard assesses brood, mite pressure, stores, queen line and spring survival together. Propolis cannot be counted as Varroa control.
Measure before deciding
- 1Choose a consistent sampling method; a standardized alcohol wash of roughly 300 brood-nest bees gives comparable estimates but is lethal to the sampled bees. Confirm the queen is not in the sample.
- 2Divide the mite count by the number of sampled bees and multiply by 100 for mites per 100 bees. Write down the method, sample size, date, yard and amount of brood.
- 3Repeat at comparable points in the season and after an action. Compare each colony with its own trend and current local extension guidance; thresholds vary with region, season and sampling method.
- 4Check brood quality, deformed wings, population, stores and robbing pressure. A low adult-bee count does not rule out mites under capped brood.
Student chapter
The rest of this chapter is behind the hive gate.
You are reading the open preview of "Varroa Monitoring in a 4H Apiary". The full chapter — about 3 minutes of it, the beginner and advanced sidebars, the printable field cards and the paired Guelph video work all sit behind a Hive Key.
What a Hive Key opens
- Every chapter in full, both reading tracks
- Printable field cards — mite thresholds, feed schedule, queenright
- The Guelph HBRC video library, paired chapter by chapter
- The Princeton season dashboard, twice a month
How to get one
Ask Mark about access to the full lessons. Hands-on workshops are a separate offer: $25 per session for youth and students, $35 for adults. No Hive Key is needed to sign up for a workshop.
Workshop prices & signup →Track your way through the curriculum
Students with a Hive Key get completion ticks, percent-through-track and a resume button across every chapter.
Open the student desk →From Section IV — Peak Flow, Summer Management & Varroa