Moving from Treatment to Treatment-Free

DISCLAIMER: The blog below is generally created from the research and instruction provided by the UK BIBBA association.  This is not my research. All credit is given to BIBBA who are helping beekeepers better understand how we can improve our Varroa management practices.

What is Varroa Resistance (VR)?

There have been several terms used to describe bees that do not die as a result of varroa infestation, including tolerance, resilience and resistance. Although they mean slightly different things, it is simpler to refer to the one term of resistance.

Common terms used be the following and are often used interchangeably:

• Hygienic behavior – Bees detect and remove infested brood.
• Varroa-sensitive hygiene (VSH) – Bees specifically target and remove reproducing mites in brood cells.

Other terms have been previously used such as grooming behavior (bees actively remove and kill mites from their own or nestmate’s bodies) and suppressed mite reproduction (SMR) where mites were thought to fail to reproduce or have reduced reproductive success within brood cells. Science has moved on and these terms are not supported by the latest scientific thinking.

NOTE: Remember that bees can exhibit some VSH and/or hygienic behavior, but they may not be fully resistant to varroa. If somebody is selling bees that are VSH, it is worth being mindful that when you change the locality of the bees, VSH is unlikely to increase as a result of this disruption. The bottom line here is that VSH does not equal VR.

Recognizing VR traits in your bees – Exoskeletons and Mite Drop on the Hive Floor

When the bees chew out the pupa, they effectively cannibalize the innards of the growing bee. They are not able to chew or consume the exoskeleton so these often fall to the floor or through the open mesh screen if one is used.

It’s all very well for bees to uncap the cells and chew out affected pupae but it does need to be done to a level where the varroa population is kept under control all year round. The actions of bees will interrupt the varroa reproduction cycle, but it has to be done to a level where the mite drop (some people may refer to it as ‘mite pressure’) is low because the mite levels are under control. Just bear in mind that a big colony may have more mites because of its sheer size. This doesn’t necessarily mean that a higher percentage of the cells are affected.

Tips to help track VR traits:

• Clear off the hive floor or monitoring board and check after a few days to see if there are exoskeletons present. If yes, this is a strong indicator of VR behaviors
• Understand that the bigger the colony, the more likely there are to be exoskeletons on the hive floor.
• If you have a mesh floor with a board underneath, you can check for exoskeletons all year round without having to disturb the hive.
• Low mite counts may mean the levels are under control

Decide on what changes to make to your treatment regime

Before you start on any change to your treatment regime(s) you may be currently using, it is important to understand that this journey may take three or four seasons to complete. It is likely to involve queen replacement(s) and your choice of future queens will strongly influence your future results. Options on changes to treatments:

Reduce the frequency of treatments

This can be done in one or two ways:

• Understand the mite count and whether or not the mite pressure is at the trigger point to justify a treatment.
• A decision can be made to skip a treatment cycle every now and then. You can choose which one to pick but it may be useful to skip the winter treatment initially as this is the most invasive treatment of a colony at a time where they would appreciate being left alone.

Reduce the amounts of chemicals used in each treatment

Again, there are a couple of considerations here:

• If your mite count is high enough to justify a treatment, bearing in mind that if the count is just above the trigger level, a smaller dose could suffice. This may go against some of the usual recommendations, but your bees may almost be coping by themselves, so you are giving them a helping hand without taking over the varroa control.
• A smaller colony will have a smaller mite drop than a larger colony, on average. Similarly, the mite drop during the summer would normally be higher as the season progresses if the varroa numbers are in the ascendancy.

Use natural treatments instead of chemicals

Certain chemicals can be used at certain times. A pivotal criterion is whether or not honey supers are on the hive at the time of treatment. There’s also the fact that most chemicals can’t get into the sealed cells so a batch of varroa may evade the chemical treatment. We know that varroa requires sealed cells to reproduce so a brood break can be a very useful (and natural) way of knocking back the varroa numbers.  The easiest way to create a brood break is to allow the colony to go through the swarming process. It is an entirely natural process, and it can be used to good effect if it is properly managed.

You can try all three options at the same time if you wish but it may be more prudent to try one option and see how it works.

Monitoring Varroa Infestation: The Foundation of Resistance Breeding

Many bees are susceptible to mite infestation to the point where it can overwhelm the colony. The first step in this process is understanding how many mites are in your colonies and identifying which hives naturally keep infestation levels low. Without accurate monitoring, beekeepers are flying blind, unable to distinguish between resistant colonies and those surviving only due to chemical intervention.

Why Monitoring is Essential

Many beekeepers treat for Varroa without checking infestation levels, assuming all colonies need intervention. This approach not only wastes time and resources but also prevents natural selection from working in your favor. By regularly monitoring mite levels, you can:

• Identify colonies with naturally low Varroa loads – potential breeding stock.
• Detect colonies at risk of collapse early, preventing mite spread.
• Determine whether intervention is necessary.
• Track mite population trends throughout the season.

Regular monitoring provides the data needed to select for resistance and reduce reliance on treatments over time.

Varroa Monitoring Methods

There are several ways to assess mite levels in a colony, each with advantages and drawbacks. Beekeepers should choose a method that is accurate, repeatable, and practical for their operation.

Alcohol Wash

The alcohol wash requires sacrificing a small number of bees.

How to Perform an Alcohol Wash:

1. Collect 300 bees from the brood nest.
2. Submerge them in alcohol (or windshield washer fluid, or Dawn dishwashing liquid) in a testing device.
3. Shake vigorously for a minute to dislodge mites.
4. Check the bottom of the device and count the mites.

Sticky Board Test (mite drop)

This passive method involves placing a sticky board beneath the colony’s screened bottom board to collect falling mites over time. A sticky board can be created from a sheet of corrugated plastic sign board and then applying a thin layer/film of petroleum jelly (Vaseline) to it.  Mineral oil or petroleum Jelly mixed with dish soap can also be used. A grid can be drawn on the board to make counting mites easier.

How to Perform a Sticky Board Test:

1. Place a white sticky board under the colony for 24-72 hours.
2. Count the mites that have fallen.
3. Divide the count by the number of days to get a daily mite drop rate.

Drone Brood Inspection

Since Varroa prefer drone brood, opening capped drone cells can reveal infestation levels.

How to Inspect Drone Brood for Varroa:

1. Identify an area of capped drone brood.
2. Use an uncapping fork to remove the pupae.
3. Look for mites on the white pupae or inside the cells.

A suggestion is to use the sticky board (mite drop) method, or some similar way of measuring mite drop. Precision is not needed here, just an indication of the mite drop averages over time. No bees will be harmed or disturbed in the process. Importantly, the sticky board can be used year-round so overwintering monitoring can happen without having to open the hive.

Interpreting the Results

Once you’ve collected data, you need to determine whether action is necessary.

• 0-2 mites per 100 bees (0-2%) – Low risk. Colonies may have natural resistance. Continue monitoring but avoid unnecessary treatment.
• 3-5 mites per 100 bees (3-5%) – Acceptable risk. Monitor closely. If mite numbers rise, consider intervention.
• 6+ mites per 100 bees (6% or higher) – Colony at risk. Mite levels are approaching colony collapse thresholds. Immediate action is required.

The same numbers can be used for average daily mite drops per colony. Infestation rates tend to rise as the season progresses, so check colonies regularly, especially in late summer.

Next Steps: Record-Keeping and Planning

Monitoring is only useful if you track your results over time. Keep a log of:

• Mite levels/drops for each colony at different times of year.
• Colony health and productivity.
• Observations of hygienic behavior or other resistance traits.

At the end of the season, this data will help identify the strongest colonies for queen rearing. Beekeepers who track their data and allow natural resistance to develop will see long-term benefits, with stronger bees and fewer losses. By making informed decisions rather than blindly treating all colonies, we can work toward a future where Varroa is no longer the dominant threat to beekeeping.

Building a Stronger Beekeeping Future

Selecting for resistance is one of the most powerful tools a beekeeper has. By allowing only the strongest, most Varroa-tolerant colonies to reproduce, we can build a bee population that thrives without constant chemical intervention.

Why Selecting for Resistance is Crucial

In nature, only the strongest survive. However, modern beekeeping often interferes with this natural process by keeping weak colonies alive with chemical treatments. This prevents evolution from favoring bees that can tolerate Varroa.

By selectively breeding from the best colonies, we accelerate natural selection. Over time, this leads to:

• Lower Varroa loads without chemical treatments.
• Increased colony survival rates.
• Stronger, healthier bee populations.
• Reduced reliance on expensive and labor-intensive treatments.

The key is choosing the right colonies to propagate.

Key Traits of Varroa-Resistant Colonies

When selecting breeder colonies, it’s important to focus on multiple traits. A colony with low mite levels but poor honey production or aggressive behavior may not be a good candidate for breeding. Ideally, look for colonies that exhibit a combination of:

• Low Varroa Levels Without Treatment. The best sign of resistance is a colony that maintains low mite counts throughout the season. If a hive has significantly fewer mites than others without intervention, it likely has valuable resistance genetics.
• Hygienic Behavior. Hygienic bees detect and remove infected brood before mites can reproduce. You can test for this by looking for uncapped pupae with Varroa mites attached.
• Overall Colony Health and Productivity. Resistance alone isn’t enough. Select colonies that:
  1. Are they productive and store adequate honey?
  2. Do they have good temperament (docile, easy to work with)?
  3. Do they have low disease levels beyond Varroa (chalkbrood, nosema, etc.)?

By selecting for a balance of traits, you ensure that future generations are not only mite-resistant but also good for beekeeping.

Steps in Selecting Breeder Colonies

After monitoring your colonies for at least one season, it’s time to identify the best candidates for breeding. Follow these steps:

1. Review Mite Monitoring Data – Compare mite counts across your apiary. The goal is to find colonies that:

• • Have lower-than-average mite levels throughout the year.
  • Show signs of hygienic behavior
  • Survive without chemical treatments.

2. Observe Colony Behavior – Look for additional resistance indicators:

• • Do they clean out diseased brood quickly?
  • Do they maintain strong populations without excessive swarming?
  • Are they productive in honey and brood rearing?

3. Rank Your Colonies – Assign a score based on mite levels, hygienic behavior, productivity, and temperament. This ranking system will help you decide which colonies are best suited for breeding.

Breeding Methods for Resistant Stock

Once you’ve identified your best colonies, you need a method to propagate their genetics. The three most common approaches are:

1. Raising Queens from Resistant Colonies – The simplest method is to raise new queens from your top-performing colonies. You can do this by:

• • Transferring larvae from a strong colony into queen cups.
  • Using a queenless colony to rear new queens naturally.
  • Allowing swarm cells to develop from a high-resistance colony. This ensures that the new queens inherit resistance traits.

2. Splitting Colonies to Expand Resistant Stock – If a colony is showing good resistance, you can split it into two or more colonies. This method:

• • Increase the number of resistant colonies in your apiary.
  • Allows you to compare resistance traits across different locations.

3. Controlling Mating for Better Genetics – Mating control is more challenging but can significantly improve resistance. Methods include:

• • Isolated mating areas – Placing mating nucs where resistant drones dominate.
  • Selecting for drone genetics – Allowing only the best colonies to produce drones for mating flights. Also known as ‘drone flooding’

Most beekeepers will rely on open mating as the above methods can be challenging to arrange. If you can put a frame of drone foundation into your best colonies, that will always help the situation.

Getting Started

Step 1: Set Up a Test Group

Understand that if you choose to go completely treatment-free the early losses can be high and, to not put too fine a point on it, a sudden full exposure to Varroa could wipe out all your colonies. An alternate solution would be to choose 10-20% of your colonies to manage without treatment. For most of us, it will mean a single colony. Monitor them closely, recording survival rates, mite loads, and behaviors. Compare them to treated colonies to see if resistance traits emerge.

Step 2: Implement a “No Rescue” Policy

No chemical treatments…let mites take their toll. This is a somewhat full-on approach, but it is with a single colony or a small percentage of your apiary. The bees can start to uncap the pupae, chew out the affected pupae and they may be able to stabilize the mite population. When it comes to preparing for winter, try to avoid helping the bees. This can mean a no feeding approach for weak colonies (except in extreme starvation cases). Natural selection is brutal in real life so there should be an approach of not replacing failing queens with new queens from the same colony – weak colonies should be allowed to fail. Only the strongest hives will survive, and those genetics will be passed on.

Step 3: Track Mite Loads and Colony Performance

Monitor the following:

• Mite counts (mite drop is suggested as it is simple and a useful indicator).
• Brood patterns and hygienic behaviors. (uncapping and recapping)
• Winter survival rates.
• After 1-2 seasons, patterns will emerge, and you’ll identify your most resistant colonies.

Step 4: Raise Queens from Survivor Colonies

Once survivor colonies have been identified then begin propagating from them by:

• Grafting from their larvae.
• Allowing them to naturally raise their own queens.
• Encouraging their drones to dominate local mating areas.

Over successive generations, your population will shift toward greater Varroa resistance. Allowing natural selection to shape Varroa resistance is one of the most powerful strategies for long-term sustainability. While it requires patience and tough decisions, the end result is a population that can thrive with minimal human intervention. By combining natural selection with strategic breeding, we’re moving closer to a future where bees manage Varroa on their own.