Varroa Mite Treatment Guide

Varroa destructor mites are the greatest threat to honey bee colonies worldwide. Without treatment, most colonies will collapse within 1-3 years. Here's how to monitor and treat effectively.

Know Your Enemy

Varroa mites are external parasites that:

• Feed on bee fat bodies and hemolymph (blood)
• Reproduce inside capped brood cells
• Spread deadly viruses (especially DWV)
• Weaken individual bees and entire colonies
• Kill colonies if left untreated

Monitoring Methods

You can't treat effectively without knowing your mite levels:

Alcohol Wash (Most Accurate)

1. Collect ~300 bees (½ cup) from brood frames
2. Place in jar with alcohol
3. Shake vigorously for 1-2 minutes
4. Strain and count mites
5. Calculate mites per 100 bees

Sugar Roll (Less Accurate, Bees Survive)

1. Collect ~300 bees in jar with #8 mesh lid
2. Add 2 tablespoons powdered sugar
3. Roll gently, let sit 2 minutes
4. Shake sugar/mites out through mesh
5. Count mites, return bees to hive

Sticky Board (Passive Monitoring)

Count natural mite drop over 24-72 hours. Less accurate but non-invasive.

Treatment Options

Organic Acids

Oxalic Acid:

• Most effective during broodless periods
• Apply via dribble, vaporization, or spray
• Safe for bees at proper doses
• Doesn't contaminate honey
• Kills only phoretic (on-bee) mites

Formic Acid:

• Penetrates capped cells—kills mites in brood
• Temperature sensitive (64-85°F optimal)
• Can harm queens at high temperatures
• Longer treatment period (2-3 weeks)

Essential Oils

Thymol-based products (Apiguard, ApiLife VAR):

• Effective at proper temperatures
• Multiple applications needed
• May affect honey flavor (don't use during honey flow)

Synthetic Treatments

Amitraz (Apivar):

• Very effective
• Resistance developing in some areas
• Longer treatment period (42 days)

Treatment Timing

• Spring: After honey supers removed, before population peak
• Late summer/fall: Critical treatment—protect winter bees
• Winter (broodless): Oxalic acid highly effective

Integrated Pest Management (IPM)

Combine multiple strategies:

• Drone comb trapping: Mites prefer drone brood—remove when capped
• Brood breaks: Cage queen or split to create treatment window
• Screen bottom boards: Mites that fall can't return
• Resistant stock: Use mite-resistant genetics when possible
• Monitor regularly: Treat based on data, not calendar

Common Mistakes

• Treating without monitoring (under or over-treating)
• Wrong treatment temperature for product used
• Not following label instructions exactly
• Treating too late in fall
• Assuming treatment worked without post-treatment check