Varroa Management Glossary: Every Term You Need to Know
The term "phoretic" refers to the mite life stage when varroa rides on adult bees outside capped brood cells. Understanding that distinction, and dozens like it, is the foundation of effective varroa management. This glossary covers every term you'll encounter in research papers, treatment labels, and beekeeping discussions.
TL;DR
- Varroa management involves specific terminology: PHI, efficacy rate, phoretic mites, VSH, IPM, and more
- Efficacy rate is calculated as: ((pre-treatment count - post-treatment count) / pre-treatment count) x 100
- Phoretic mites are those on adult bees (not in brood); only phoretic mites are killed by most treatments
- PHI (pre-harvest interval) is the required gap between treatment end and honey super addition
- VSH (varroa-sensitive hygiene) is a heritable bee trait that suppresses mite reproduction in brood cells
- VarroaVault uses standard industry terminology aligned with HBHC and USDA guidelines
A
Acaricide
A pesticide specifically targeting mites (acarids). In varroa management, registered acaricides include amitraz (Apivar), oxalic acid (Api-Bioxal), formic acid (MAQS, Formic Pro), thymol (Apiguard, ApiLife VAR), and hop beta acids (HopGuard). VarroaVault's treatment log includes all registered acaricides in its product list.
The gold-standard mite counting method. A 300-bee sample from the brood nest is shaken in 70% isopropyl alcohol, which dislodges mites from bees. The mites are counted in the wash liquid. Provides 95%+ sensitivity for threshold detection.
Amitraz
The active ingredient in Apivar. Works by disrupting the octopamine nervous system in mites. Resistance to amitraz is documented in several US states. See also: Apivar.
Apis cerana
The Eastern honey bee, native to Asia. Co-evolved with Varroa destructor and has developed behavioral defenses (grooming, hygienic brood removal) that allow natural mite population control without chemical intervention.
Apis mellifera
The European honey bee. The most widely managed species for honey production and pollination globally. Has no natural behavioral defenses against Varroa destructor, making management essential.
ApiLife VAR
A thymol-based varroa treatment in tablet form. Applied in multiple 1-week intervals. Requires ambient temperature above 59°F for efficacy.
Apiguard
A thymol gel varroa treatment applied in two 50g doses, 14 days apart. Requires ambient temperature above 59°F. Approved for use in certified organic operations under USDA NOP.
Api-Bioxal
The registered brand name for oxalic acid dihydrate labeled for varroa treatment in the US. Used by dribble, vaporization (sublimation), or spray. The only EPA-registered OA product available in the US.
Apivar
Plastic slow-release strips containing amitraz. Applied at 2 strips per hive for 42-56 days. Must be placed in the bee cluster. Cannot be used with honey supers in place.
B
Brood break
A period when a colony has no or minimal capped brood. Can occur naturally (winter) or be induced (by caging the queen or removing her). Creates conditions where most mites are phoretic and vulnerable to OA treatment.
Broodless period
The time in winter when the queen has stopped laying and no capped brood is present. The most effective window for OA dribble treatment. Typically November-January in northern US states, though warmer winters have shortened or eliminated this window in many regions.
C
Capped brood
Brood cells with a wax cap covering the developing pupa. Varroa reproduces inside capped worker brood (12 days capped) and drone brood (14-15 days capped). Mites inside capped cells are inaccessible to most topical treatments. This is why OA dribble requires a broodless period for high efficacy.
Colony collapse disorder (CCD)
A pattern of colony loss characterized by rapid disappearance of adult worker bees without dead bees present. While CCD's exact causes remain debated, varroa and the viruses it transmits are consistently implicated as primary or contributing factors.
Coumaphos
The active ingredient in CheckMite+ strips. A synthetic acaricide (organophosphate) that was widely used before resistance became common. Prohibited under USDA NOP. Accumulates in beeswax at levels that can persist for years.
D
Deformed Wing Virus (DWV)
The most economically damaging bee virus transmitted by varroa. Causes developmental defects in emerging bees including crumpled, stunted wings. Colonies with high varroa loads have DWV titers hundreds to thousands of times higher than low-mite colonies.
Drone brood
Male bee brood. Drone cells are capped for 14-15 days (longer than worker brood), making them preferred reproductive sites for varroa. Approximately 8x higher mite infestation rates in drone versus worker brood. Drone frame removal is used as a supplemental mite management tool.
E
Economic threshold
The infestation level at which expected colony damage exceeds the cost of treatment. For varroa, the generally accepted threshold is 2% in late summer/fall (protecting the winter bee cohort) and 3% during the active season. VarroaVault's default thresholds follow HBHC recommendations.
Efficacy
The percentage mite reduction achieved by a treatment. Calculated as ((pre-count % - post-count %) / pre-count %) x 100. EPA label claims for registered acaricides specify minimum 90% efficacy. VarroaVault calculates efficacy automatically from pre and post count entries.
F
Fat bodies
The metabolically active tissue in bees analogous to the liver and fat storage of vertebrates. Varroa feeds on bee fat bodies (not hemolymph as previously believed), damaging protein metabolism, immune function, and vitellogenin production in affected bees.
FIFRA
Federal Insecticide, Fungicide, and Rodenticide Act. The US law governing pesticide registration and use. Requires that all varroa treatment products be EPA-registered. Using unregistered products (such as grocery store oxalic acid) for varroa treatment is a FIFRA violation.
Formic acid
The active ingredient in MAQS and Formic Pro. An organic acid that penetrates capped brood cells, reaching mites in the reproductive phase. Requires 50-85°F ambient temperature for safe and effective use. Approved under USDA NOP.
Formic Pro
A formic acid strip product that releases formic acid more slowly than MAQS, reducing bee stress risk in warm weather. 14-day treatment period.
H
HBHC (Honey Bee Health Coalition)
An organization of beekeeping industry stakeholders that publishes varroa management best practice guidelines. Their Varroa Management Guide is the most widely cited management reference in US beekeeping education. VarroaVault's default thresholds and monitoring frequencies align with HBHC recommendations.
HopGuard III
A hop beta acid varroa treatment that can be used with honey supers in place per label. Approved under USDA NOP.
Hygienic behavior
A behavioral trait in some Apis mellifera populations where workers detect and remove diseased or parasitized brood before pathogens or pests can complete their life cycle. VSH (Varroa Sensitive Hygiene) is a specifically selected form of hygienic behavior that targets varroa-infested cells.
I
Infestation rate
The percentage of adult bees in a sample that carry phoretic mites. Calculated as: (mites counted / bees sampled) x 100. For a 300-bee sample with 9 mites: (9/300) x 100 = 3%. This is the primary metric in VarroaVault's count log.
M
MAQS (Mite Away Quick Strips)
A formic acid product consisting of gel-matrix strips applied in pairs for 7 days. Can be used with honey supers on per label at temperatures of 50-85°F.
Mite bomb
A colony with extremely high mite loads (often 5%+) that spreads mites through robbing and drift to neighboring colonies. Mite bombs are a community-level varroa management concern.
N
Natural mite drop
Mites that fall naturally from bees during grooming and movement, collected by a sticky board under a screened bottom board. Used as a trend monitoring indicator but not reliable for precise infestation percentage calculation.
NOP (National Organic Program)
The USDA program governing certified organic agricultural production. NOP rules specify which varroa treatments are allowed (OA, formic acid, thymol, hop beta acids) and which are prohibited (amitraz, coumaphos, tau-fluvalinate) in certified organic honey operations.
Nurse bees
Worker bees 1-14 days old that tend brood cells. They carry 3-4x more phoretic mites than foragers. Sampling nurse bees from the brood nest gives the most accurate mite count.
O
OA (Oxalic acid)
A naturally occurring dicarboxylic acid used as a varroa treatment. Applied by dribble, vaporization, or spray. The dribble method requires a confirmed broodless period for high efficacy (95-97%). Vaporization (extended protocol) works even with brood present.
Oxalic acid vaporization
The sublimation of OA crystals using a heating element to produce vapors that coat bees and mites in the hive. Extended protocol (3-5 applications, 5-7 days apart) achieves 90-95% efficacy even with capped brood present.
P
PHI (Pre-Harvest Interval)
The minimum time that must pass between the last application of a treatment and the harvesting of honey. Set on product labels and regulated under FIFRA. VarroaVault tracks PHI for every logged treatment and alerts you before expiry.
Phoretic mite
A varroa mite in the non-reproductive phase, riding on an adult bee. Phoretic mites are the target of OA dribble and sugar roll counting. During the active season, only 10-20% of mites are phoretic at any time; the rest are in capped brood.
Population modeling
The use of mathematical models to project future mite population based on current count, brood cycle length, and colony size. VarroaVault's AI uses your count history to project mite load 30 days forward.
R
Resistance
The genetic ability of a mite subpopulation to survive exposure to an acaricide. Resistance develops through selection pressure when the same product is used repeatedly. Documented in US varroa populations for tau-fluvalinate (widespread) and amitraz (emerging in some areas).
Reproductive cycle
The process by which a female varroa mite enters a capped brood cell, lays offspring, and emerges with the adult bee. Worker brood cells support one complete cycle (producing 1-2 viable daughters). Drone brood cells, capped longer, support 1-3 viable daughters.
S
Sticky board
A card with adhesive surface placed under a screened bottom board to collect naturally-falling mites for count estimation. Useful for trend monitoring. Not reliable for precise infestation percentage calculation due to seasonal variability in natural drop rates.
Sugar roll
A non-lethal mite counting method where bees are coated with powdered sugar and mites dislodged by shaking. Returns 30-40% fewer mites than alcohol wash on the same colony. Acceptable for trend monitoring; not ideal for threshold treatment decisions.
T
Tau-fluvalinate
The active ingredient in Apistan and Mavrik strips. A synthetic pyrethroid acaricide. Widespread resistance in US varroa populations has made this product largely ineffective in most areas.
Threshold
See: Economic threshold.
Thymol
A naturally occurring terpenoid compound derived from thyme oil. Used in Apiguard and ApiLife VAR. Requires above 59°F ambient temperature for effective vapor release. Approved under USDA NOP.
V
Varroa destructor
The scientific name of the varroa mite. A parasitic mite of honey bees that feeds on fat bodies of developing pupae and phoretic mites on adult bees. Originally a parasite of Apis cerana; jumped to Apis mellifera in the 20th century.
Varroa jacobsoni
A related but distinct varroa species found primarily on Apis cerana in parts of Asia. Originally thought to be the same species as Varroa destructor before taxonomic separation in 2000. V. jacobsoni has limited ability to reproduce in Apis mellifera.
Vitellogenin
A storage protein in honey bees produced primarily in fat bodies. Critical for winter bee longevity and nurse bee function. Mite-damaged bees with impaired fat bodies produce lower vitellogenin levels, reducing their survival in winter.
VSH (Varroa Sensitive Hygiene)
A selected behavioral trait in some Apis mellifera breeding lines. VSH bees detect and remove mite-reproductive cells before the mite completes its reproductive cycle, dramatically reducing mite population growth. VSH queens are commercially available.
See also: Complete varroa management guide and VarroaVault varroa mite treatment software.
Frequently Asked Questions
What does PHI mean in beekeeping?
PHI stands for Pre-Harvest Interval, the minimum time required between the last application of a varroa treatment and harvesting honey. PHI is set on each product's label and is legally required under FIFRA. For example, Apivar must be removed before supers are added; Apiguard requires no supers during treatment. VarroaVault tracks PHI automatically for every logged treatment.
What is a phoretic varroa mite?
A phoretic varroa mite is one that is riding on an adult bee rather than reproducing inside a capped brood cell. Phoretic mites are accessible to contact treatments like OA dribble. During active brood season, only 10-20% of mites are phoretic; 80-90% are in capped cells. This is why the broodless period is so valuable for OA dribble treatment.
What does economic threshold mean for varroa?
The economic threshold is the infestation level at which the expected damage to the colony (mite-damaged bees, virus transmission, reduced winter survival) exceeds the cost of treatment. The commonly accepted threshold is 2% infestation rate in late summer and fall (to protect the winter bee cohort) and 3% during the active season. These thresholds are published by the Honey Bee Health Coalition and are used as VarroaVault's default alert settings.
How do I know if my varroa treatment is working?
Run a mite count 2-4 weeks after the treatment ends and compare it to your pre-treatment count. The efficacy formula is: ((pre-count - post-count) / pre-count) x 100. A result above 90% indicates effective treatment. Results below 80% should trigger investigation for possible resistance, application error, or reinfestation. Log both counts in VarroaVault to track efficacy trends across treatment cycles.
How often should I check mite levels in my hives?
At minimum, once per month (every 3-4 weeks) during the active season. Increase to every 2 weeks when counts are near threshold or after a treatment to verify it worked. In fall, monitoring frequency matters most because the window to treat before winter bees are raised is narrow. VarroaVault's monitoring reminders can be set to your preferred interval for each apiary.
What records should I keep for varroa management?
Each record should include: date of count or treatment, hive identifier, monitoring method used, number of bees sampled, mites counted, infestation percentage, treatment product name and EPA registration number, dose applied, treatment start and end dates, and PHI end date. State apiarists typically expect this level of detail during inspections. VarroaVault captures all of these fields in a single log entry.
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 information in this guide is most useful when you have your own mite count data to apply it to. VarroaVault stores every count, flags threshold crossings automatically, and builds the treatment history you need for state inspections and effective management decisions. Start your free trial at varroavault.com.