Death, disease, and dementia.
The aftermath of the Varroa Destructor is absolutely devastating.
These tiny red parasites plague the honey bee population and can take down a hive in a single year.
Ever since they arrived in the states in 1987, Varroa Mites have been the bane of US beekeeping.
They have now become the number one killer of all beehives; taking the lives of far more bees than both agricultural pesticides and human error.
True to their name, these Destructors wreak havoc on your hive.
They are opportunistic and can play the long game by spreading disease and weakening your hive generation after generation.
The worst part about these mites is that they go virtually undetected. You likely will never see them unless you intentionally monitor them.
In this article, we'll expose these silent killers, teach you how to test for them, and show you how to take back your hive.
Table of Contents (Click to Skip Around)
- What Are Varroa Mites?
- What Problems Can Come From Varroa Mites?
- - Issues With Underdevelopment
- - Issues With Diseases
- Counting Varroa Mites
- - Why Should I Count My Varroa Mites?
- - How to Count Varroa Mites?
- How to Treat Varroa Mites
- - Broodless Period
- - Before Putting Supers On
- - While Supers Are On
- - Once Temperature Drops
- - After Supers Are Off
What Are Varroa Mites?
Like ticks on a dog, Varroa Mites are parasites that will latch on to, feed off of, and introduce various diseases to your honey bees. While doing so, they hitch a ride to their breeding grounds - the honey bee brood chamber.
Once they arrive in the brood chamber, they hop off the honey bees into a larva-filled cell.
Just in time, they join the larva 15 hours prior to when their cell is sealed off for the pupa stage.
Entombed alongside your bees, the Varroa Destructor begins to feast.
This video quickly illustrates the lifecycle of a Varroa Mite and how they spread from hive to hive.
What Problems Can Come From Varroa Mites?
Varroa Mites cause both short and long-term damage to your bees.
In the short term, the individual bee will encounter issues with underdevelopment that come from having the life sucked out of it.
In the long term, the whole hive will contract and spread many diseases that originate from the Varroa Destructor. As of now, scientists know of 24 unique viruses that affect honey bees!
Once infected, many of these viruses will then spread from bee to bee. Throughout the following generations, the disease will continue to permeate your hive until it collapses entirely.
Issues With Underdevelopment
After the Varroa Mite crawls to the underbelly of the honey bee larva, it cuts a crevice into the cuticle.
This wound exposes the fleshy fat within the bee's exoskeleton.
The Varroa Mites consume this fat to survive and develop their offspring. Unfortunately, it is also what helps develop your bees.
Without this fat, your bees will likely have one or more of these symptoms:
- Reduced Life Span - Summer/spring bees live for 4 to 6 weeks and have many replacements. The winter bees don't have replacements since the queen doesn't lay eggs during the extremely cold months. If your winter bees have had their fat consumed by Varroa Mites, they may not live the full 4 to 6 months that they need to in order to survive the winter
- Reduced Immunity - Your bees' immune systems will be more likely to be affected by both diseases and pesticides
- Reduced Sperm Count - Along with physical underdevelopment, your drones won't be able to compete with other drones. This leads to a decrease in the genetic diversity of the queens in your area
- Increased Queen Turnover - The worker bees can sense that the new bees aren't fully developed. Because of this, workers will blame the queen for being poorly mated. This will increase the supersedure rate and can affect recently mated queens
- Increased Dementia - Underdeveloped foragers who leave the hive are less likely to return due to forgetfulness. This "honey bee drift" is also a contributing factor to the spread of Varroa Mites from one beehive to another
Issues With Diseases
The cut on your bees not only allows the Varroa Mites to rob nutrition from them, but it also provides an entrance for pathogens and viruses.
The Varroa Mites will pry the wound open with their lateral lips and prevent the laceration from healing.
A prolonged exposure like this invites viruses that are naturally in the hive to foster within the young bee. There are also many not-so-natural viruses that the Varroa Mites contaminate your hive with.
Some of the viruses that are brought about by Varroa Mites are:
- Deformed Wing Virus (DWV) - This virus is named after the obvious symptom it causes. The virus stunts the development during the pupa stage and results in shrunken or deformed wings. These wings cripple the bees ability to fly
- Cloudy Wing Virus (CWV) - Much less is known about this virus than DWV. It is questionable if this virus is spread by Varroa Mites, but it is believed to be linked to their presence within a hive
- Slow Paralysis Virus (SPV) - This virus causes the front two pairs of your honey bees' legs to be paralyzed. It will eventually kill its hosts
- Black Queen Cell Virus (BQCV) - Most commonly found in the queen production industry. The visual symptoms of this virus only affect the queens. Once infected the queen will die and turn a pale yellow, then brown, and finally black
- Sacbrood Bee Virus (SBV) - One of the most widely distributed viruses. It infects the larvae and results in failure to pupate which leads to a quick death
- Israeli Acute Paralysis Virus (IAPV) - It's been in the states since 2002. Studies show that IAPV affects the cells' mitochondrial function. The mitochondria are in charge of producing energy that powers the cell's biochemical reactions. Lacking energy, the cells become paralyzed
- Acute Bee Paralysis Virus (ABPV) - Once transmitted to the bees via the Varroa Mite, the bees will spread this virus to others via the salivary gland secretion that they use to feed the brood
- Kashmir Bee Virus (KBV) - This virus can harm both your brood and adult bees. Infected larvae may survive on to adulthood, but adults that are infected will die within a few days of exposure
- Chronic Bee Paralysis Virus (CBPV) - This virus can be identified by an abnormal trembling, shiny/hairless abdomen, or flightlessness in your bee. The infected adult bees will die within a week and will lead to mounds of dead bees outside the colony
Counting Varroa Mites
Monitoring your mites can do wonders for your apiary and the bee community at large.
To count your mites you'll need a mason jar, a lid, and a screen. You could also purchase one of these Varroa EasyCheck systems.
You'll also need some powdered sugar, rubbing alcohol, or windshield washer fluid.
Why Should I Count My Varroa Mites?
Some beekeepers don't see the point in testing their hive before they treat it. They think it's useless because they're going to have to treat their hives anyways.
This is the wrong approach though.
While it's likely true that you're going to have to treat them anyways, counting your mites can help us all save the bees.
By knowing which hive is naturally the best at resisting Varroa Mites, you can reward that hive by splitting it and furthering its genetics and behaviors.
This promotes a more healthy hive and is likely the same process that the apiary you bought your bees from practices.
How to Count Varroa Mites?
To get a Mite Count from your hive you can use powdered sugar, rubbing alcohol, or window washing fluid.
The method for all three materials is the same.
Both rubbing alcohol and window washing fluid will give you a more accurate count than powdered sugar, but you will kill the bees that are tested.
Generally, this is seen as collateral damage for the greater good.
In this article, we'll go over the Sugar Shake Method. There is a video below to illustrate the process.
- Step 1 - Collect about 300 bees (1/2 a cup) into a mason jar. To do this, you'll take your 1/2 cup measuring tool and put it at the top of the frame. Then you'll run it downward while barely touching each bee's back. As you touch them, they'll usually let go of the frame and fall into the cup as you lower the cup downwards (see the video below at minute mark 1:50)
- Step 2 - You'll then put a screened lid (1/8th inch holes) on the jar, pour 2 tablespoons of powdered sugar on them through the lid, and roll the bees in the sugar for two minutes. This may sound like it could harm the bees a bit, but they're resilient and it's nothing compared to the thousands of bees that could die from an out of control mite problem
- Step 3 - After 2 minutes, the bees are fully coated and the mites have dislodged from your bees as the powdered sugar jams itself into the Varroa Mites' joints
- Step 4 - Then you'll shake out the powdered sugar through the screened lid onto a white plastic background. This allows the powdered sugar and the Varroa Mites to come out of the lid, while the bees remain in the mason jar
- Step 5 - Count the amount of Varroa Mites that are on the white background. You can pour a little water onto the white background to help clean the sugar off the Varroa Mites and make them more visible. This will make it easier for you to count
- Step 6 - Write down the number you've counted in your notes. If it's more than than 4, you have a mite problem and will need to take care of it
How to Treat Varroa Mites
There are plenty of different treatments for getting rid of Varroa Mites.
For good reason too. If you continue to use the same treatment over and over, oftentimes the mites start to become resistant to it.
To avoid this resistance, it's recommended that you change your treatments up throughout the year.
You likely won't have to use every treatment in the following list. Rather, this list tells you which treatment is best for the time of year that you're in.
If after doing a Mite Count, you find that you need to treat your hive, refer to the following time periods below:
The broodless period usually occurs between November and February. During this time, we recommend the OAV wand.
Your queens will naturally stop laying eggs in the cold months of late fall and winter.
This means that all of the Varroa Mites are scrambling around the hive looking for a cell with a host in it. While all the Varroa Destructors are exposed, you'll want to hit your hive with an Oxalic Acid Vaporization (OAV) treatment.
The winter is perfect for OAV for two other reasons.
OAV is effective in temperatures down to 37 degrees Fahrenheit.
The other reason is that you don't have to open up the hive in order to do this treatment -- you can just stick the OAV wand through the entrance.
Before Putting Supers On
Most beekeepers put their honey supers on around April or May once the brood box(es) are full. During this time, we recommend powdered/confectioners sugar.
Before you put on your supers for the year there's a great opportunity to do a couple of treatments of powdered sugar.
Much like the Sugar Shake Counting method we talked about earlier, you'll use powdered sugar to dislodge the Varroa Mites.
This time though, you'll use it on the entire hive. Using about 1 cup per brood box.
This way of defeating Varroa Mites is the best for this time of year because you'll be feeding your hive anyways.
So to go along with the sugar syrup that you're feeding your hive, you'll give them some powdered sugar as well.
If possible, you'll want to pulverize your own powdered sugar by putting the granular sugar into the blender. This will result in a powder sugar that doesn't have cornstarch in it. The bees don't digest the starches as well as pure sugar.
As you can see in this video, the beekeeper will take a cup of powdered sugar and a fine mesh strainer to spread it between the frames throughout the hive. He'll brush the remaining bit that has landed on top of the frames down into the hive as well.
While Supers Are On
Your honey supers will be on for most of the spring and summer. During this time, we recommend purchasing some Drone Trapping Frames.
This method can be done regardless of the weather outside and regardless of if you have supers on the hive.
While these frames are a peculiar shade of green, that's not the part that's special about them.
Their unique attribute is that they have attached foundations that produce larger cells once the bees build wax on them.
The queen will then fill these larger cells with drone eggs.
As we learned earlier, the Varroa Destructor prefers to feed and mate in drone cells because they are sealed and protected for longer. This means they can produce more fertile females per litter.
To use this frame, you'll put it in your hive in the 2nd or 3rd frame position.
Once the larva has all been sealed (between 18 and 24 days), you'll pull the frame out of the hive and place it in the freezer for 48 hours.
This will kill both the drone pupae and the Varroa Mites inside.
Drones don't really do anything in your hive, so if it helps you kill mites, then it's worth getting rid of them.
If you decide to use this method, be sure to take the Drone Trapping Frames out of the hive before the drones emerge, otherwise, you'll have only heightened the issue of Varroa Mites instead of managed it.
Once Temperature Drops
Once temperatures finally fall below 85 degrees Farhenheit consistently, we recommend Mite Away Quick Strips (MAQS).
The MAQS are gel strips impregnated with Formic Acid that you lay on top of your brood boxes.
There are two unique properties to this Formic Acid.
One is that it's been approved by the FDA to be used even when you have honey supers on the hive.
The second is that Formic Acid has the ability to penetrate through the wax of capped brood cells.
This means every Varroa Destructor in the hive can receive a dose even during the brood period.
One caution is that there is a temperature limit. You do not want to use MAQS when the temperature outside could reach over 85 degrees Fahrenheit within the 7-day span of treatment.
Hopefully, the temperatures in your area are low enough to use MAQS in July or August while the Varroa Mites are at their worst.
After Supers Are Off
Once you've pulled off the honey supers for the year, it is then safe to use Apivar.
If you just used MAQS, it's likely that you don't have to use Apivar as well. You should count your mites first.
However, if your mite count is still high, it'd be good to switch to a different chemical. It's likely that the mites had gained some resistance to the Formic Acid in MAQS.
The active ingredient in Apivar is Amitraz which paralyzes the Varroa Mites. Once paralyzed, they'll fall to the bottom board, and eventually, die from starvation.
Another reason someone may use Apivar is if you have extremely long summers and the heat doesn't come down till late fall. If this is the case for your area, you'll want to use Apivar once you've taken off your supers for the year.
It does not have any limitations when it comes to temperature, but Apivar will take 42 days for the full effect to hit your hive.
Varroa Destructors are true to their name.
They quickly wreak havoc on a hive.
These silent killers cause short-term damage by producing underdeveloped bees.
As well as long-term damage through spreading diseases that permeate throughout the hive.
On the bright side, Varroa Mites are manageable.
We can all help save the bees if we are diligent in counting the mites and administering treatments as necessary.
If we don't do anything about it, not only will your own hive perish, but the mites will move on to its next victim.
Continue Your Bee Journey!
The following articles could be very helpful in taking your next steps.
Recommended First Hives
If you haven't yet purchased your first hive, we recommend one of our Starter Hive Kits. Each kit comes with all the essential parts of a beehive and the accessories you'll need for your first few years of beekeeping. We consider them "Nuc Ready" which means they come with 5 frames and are ready for the 5 that you buy when you purchase a 5-Frame Nuc of bees.