Varroa Mite Treatments & Control
Varroa mites are one of the most serious challenges facing honey bee colonies today. Most every beekeeper will be faced with finding effective varroa mite treatments at some point. This article provides a simple overview of the main varroa mite control methods used by beekeepers currently. This is a general look at the struggle as treatment options are always changing.
Successful varroa control involves understanding your options. You must choose the method that fits your bees, your management style, time of year, eta. There are no perfect answers in dealing with this major pest of honey bees.
Why Varroa Control is Necessary
The average bee colony has several types of mites inside-most cause no harm. Varroa mites (Varroa destructor), however, are a different story.
Varroa mites weaken bees by feeding on them and spreading various bee viruses throughout the colony.
Mites reproduce quickly with newly hatched mites feeding on developing bee larva. This sets up a deadly cycle of sick, weak bees. When mite levels become too high, colonies often decline and collapse quickly.
This is why most beekeepers need to use some method of reducing mite populations and slowing down their impact on the hive.
Key Things to Know Before Treating for Varroa
Before choosing a varroa mite control method, there are a few things to keep in mind.
- not all treatments are equally effective
- some have temperature restrictions
- some available varroa mite treatments (yes, even approved treatments) may contaminate the honey and beeswax in the hive (at supposedly safe levels)
- some treatments can not be used when honey supers are on the hive
There is also no single answer to the question, “how many mites are too many”. Treatment decisions are based on mite levels, season, etc.
We beekeepers have several methods for testing for varroa mites to give an estimation of mite numbers.
For more info, see my guidelines in – “when to treat your bees for varroa mites“. Determining the varroa mite threshold for your apiary is often a moving target.
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Chemical Varroa Treatments (Organic & Synthetic)
Research has provided us with several chemical treatment options for varroa control. These products differ in how they work and when they can be used. Your own beekeeping philosophy may determine which you use:
- Organic (soft) Varroa Treatments
- Synthetic Treatment Options
Soft Varroa Treatment Options
Many of these treatment products are organic. They are derived from naturally occurring substances and are widely used by beekeepers.
Soft methods of varroa control are my favorite. I have had success with all that I have tried – but I have also lost colonies along the way.
They can be not as effective as synthetic options – you must not let the mite population get out of control before using them.
Treatments included in this category include:
- formic acid
- thymol based products
- oxalic acid
Formic Acid
Formic Pro is currently my best option when using formic acid. It words as a fumigant and kills mites in capped brood – (many others do not).
This organic treatment can be troublesome in hot weather – a big problem in my region. Extreme temperatures above 92° F during the treatment application may cause colony absconding.
I periodically use formic acid treatments in my colonies, but not during hot weather.
Some beekeepers have reported queen that died or a reduction in brood production. I never had any problems while using this product. But, I always follow the directions on the label!
Thymol Products
Thymol products also do a good job of varroa control in beehives. I have used several of these over the years with good results. Yet, they must be used in a particular temperature range- a challenge for southern beekeepers.
Apigard
Apiguard is a thymol gel that acts as a fumigant. Temperatures should be between 59° F and 105° F. (Personally, I would want it to be much cooler in my humid climate before I used it in my hives.) Use twice at 2-week intervals to complete a mite control plan.
Api Life VAR
CONFUSION ALERT: There is a difference between Apivar and Api Life V A R. One is a synthetic chemical and one is a softer essential oil based treatment. Both are approved for use in beehives.
Api Life Var (thymol, eucalyptol oil, menthol, camphor) It has proven very effective. The product features a green spongy pad impregnated with oils and works as a fumigant.
Pads are placed on the top bars inside the hive – 3 times at 7 day intervals. An acceptable temperature range is between 65-85° F.
Oxalic Acid
Oxalic acid (Oxalic acid dihydrate-organic acid) is used in two ways for mite control – as a drizzle or as a fumigant (vaporization).
- drizzle – used when little to no brood is present
- fumigant – vaporization method
Oxalic Acid Vaporization (I used this method). A small amount of OA crystals are placed on a special wand and slid into the hive. The wand heats causing the crystals to vaporize.
As the vapor cools, crystals reform inside the hive. Honey bees remove the acid crystals and expose varroa to the substance.
Oxalic acid vaporization is a very effect varroa mite treatment during Fall and Winter – times when less brood is in the hive. It does not kill mites hidden inside the brood cells – many beekeepers use timed repeated treatments to kill mites at each stage.
But, some researchers feel the control is not good enough. That even using multiple treatments over a period does not reduce the mite load enough.
VarroxSan
VarroxSan is an organic mite treatment that used special strips, impregnated with oxalic acid. The slow release method is able to kill mites over a longer time period.
Even better, it is not heat sensitive and where approved can be used when honey supers are on the hive.
Synthetic Treatment Options
Synthetic treatments are manufactured chemicals developed specifically for varroa mite control. They are effective and approved because they pose little risk to the bees or humans.
However, heavy usage has resulted in varroa resistance to some of these products. If you use them, it is important to rotate them. Use your own judgement when deciding what to put in your hive – weigh the risks-rewards.
Common Synthetic Treatments include:
- Amitraz-based products
- Fluvalinate
- Coumaphos
Apivar (amitraz)
Apivar (amitraz) is a synthetic miticide that kills by contact. Impregnated strips are placed near the brood nest for a period of time. This chemical was used for mite control in the past, then pulled and now allowed again.
Apivar has time usage restriction. Do not place honey supers on your colony for at least 2 weeks after treatment. Low levels of residue can be detected in the beeswax and honey.
Apistan (fluvalinate)
Apistan (fluvalinate) is an older substance used for mite control in honey bees for years. Impregnated strips kill by contact – they too are placed inside the hive and removed after a certain time period.
Reports of wide spread resistance to fluvalinate has been reported in colonies over recent years. Also, chemical residues may persist in beeswax in the hive. Most beekeepers that I know no longer use it.
Checkmite+ (coumaphos)
Sold as Checkmite+ – coumaphos is another product that has been used for varroa control and coincidently also aids in controlling Small Hive Beetles.
As great as that sounds, there are serious considerations within the industry regarding the negative effects in the hive and possible bad effects on drone honey bees.
I have never used this product. Sold as a restricted pesticide in some areas – you may need a veterinarian approval to purchase.
IPM (Integrated Pest Management) Approaches
Chemicals are not the only way to fight varroa. In an integrated pest management plan (IPM) beekeepers use several methods to control varroa mites.
Mechanical Methods
Mechanical methods-such as the use of screened bottom boards allowing some mites to fall to the ground and perish was exciting several years ago.
Now, I have little confidence (IPM – screened) as a varroa control the number of mites removed is just too insignificant.
For a time, the use of powdered sugar become a popular treatment plan for varroa. Dusted over the bees and top bars – as the bees groomed themselves to remove the sugar – varroa mites would be knocked off.
I lost 10 hives to that experiment one summer. Though, I must admit that the white bees looked like little flying ghosts for a while – rather cute.
Drone Brood Removal
Some beekeepers still practice drone removal to reduce mite populations. Drones are the mites favorite host. Special green drone frames are used to encourage drone production.
Once filled with capped brood and developing mites inside, the frame is removed and frozen. This kills the mites and the drone brood is sacrificed as well.
Personally, I am not a fan of this method. You must remember to remove the frame at the proper time. Otherwise, you have just created a mite maternity ward.
Promoting Bee Health
One thing we have learned is that the health of the bee colony plays a role in mite control. Several products including homemade essential oil recipes for bees are used.
And genetics play a role as well. Some strains of honey bees do a better job of controling varroa. When buying a new queen bee – finding one that has some mite resistance is a big plus.
Natural beekeeping or even treatment free is a great idea but you are not likely to be successful unless you have the right bee genetics.
FAQs
No. At this time, varroa mites cannot be completely eliminated. The goal of varroa management is to keep mite levels low enough that the colony can remain healthy and productive.
Yes. Varroa mites can move between colonies through drifting bees, robbing behavior, and collapsing hives. This is one reason why consistent mite management is important, even if your own bees appear healthy.etc.
Yes. Colonies can appear strong while mite levels are increasing. Without monitoring and timely control, even strong hives can decline rapidly due to varroa-related viruses.ey were effective.
Yes, it is common for varroa mites to develop resistance to treatments – especially chemical treatments such as fluvalinate or coumaphos – rotate your treatment methods.
The Future of Varroa Mite Control
Varroa mite control methods are constantly evolving. We are all looking for that “silver bullet” that will take us back to those pre-varroa days.
In spite of new developments (such as dsrna products), we have not found the perfect answer. Learn, study and listen to what is working for other beekeepers in your area.
Final Thoughts
What you choose as your varroa mite treatment for bees is as individual as you. The goal is not necessarily a complete kill of every mite – rather a reduction in varroa mite populations. If you are new to beekeeping – my online beginners class will help you get on a path to success.
Charlotte, have you any information on extended release oxalic acid. I am aware it is not commercially approved at this time. But as an experimental treatment for trial. Only have two hives and expense of vaporizer seems out of line.
Thank you, Wesley
I do not. I know that the idea is really appealing and several researchers have worked on it but I have not heard of any that have been able to get the dose just right. Though they don’t last as long – some of the cheaper vaporizers might work for a while with only 2 hives.
We treated our nine hives 5 days apart with Oxalic Acid for five days. It was thorough and early in the day when the hives were still quiet. We did this for five treatments, waited one week and inspected for mites and we did have mites, often more than one. We have restarted the treatments but I don’t know whether my bees are picking up mites from other local hives, whether we have the timing wrong, or if this very hot wet weather makes miteless living impossible. The bees still have nectar to gather, are peaceable, busy and don’t act desperate.
But I do.
Mary, depending on where you live – I think it is impossible to have a mite-less hive. They do pick them up from flowers, drifting bees etc. It is good to check your colonies after any treatment for effectiveness. Good for you that you know this is important. Finding a few mites is not a problem – a large infestation is a different matter.
I have treated while feeding. In general, as odd as it sounds, even feeding can cause the colony a little stress so that’s why it is usually recommended to remove them. However, I think being hungry would cause more stress . So if it were me, I would probably just go ahead.
Here in Texas we are currently feeding our bees because of the dearth. Is there a treatment where we can leave the sugar syrup in the hive or do we need to remove the feeders for any of the treatments?
why do we vaporize with OA 7 days apart for 3 weeks when drones are capped for 24 days?
My best answer to that – any type of treatment does stress the colony to a degree. We can’t get rid of every single mite in the colony but want to knock them down below a threshold. While we won’t hit every new mite in drone cells (over 21 days), we are covering a long period of time that should help control the infestation.
Treated hive in fall for high mite load with formicpro. Surprisingly this hive wintered so well that I did a split in the spring. When my population started to dwindle 6 weeks later I checked for mites and found 3 out of 100 also concerned for failing or missing queen. I did one strip of formicpro for 1 week and ordered a new queen. Is it dangerous to continue with Second strip? Also how long do I wait to introduce new queen after treatment? I live on coast of SC.
I don’t like to requeen until after treatments are finished. You can – its just a bit risky
Hi Charlotte and thank you for all goods informations.
I have a lot of mites this summer cause i did not treat last fall like i had planned.
I am wandering if it’s too hot (26 C, 78.8f) to use OA vap? I dont have
anything else to treat and i just saw a lot of mites in my hives.
I know it will not kill in the brood but that it might lower the amount of mites a bit.
I can not find anything about temperature and oa vap on a web. I know that is usually for spring and fall treatement.
Thanks a lot for your time
Nini
I do it in the summer when I have to. I try to avoid temps over 90.
New beekeepers, treat your bees or you will be buying new bees every year after winter, that makes your bee supplier happy. Check your bees for mites and treat if needed. Also treat in the summer and that is for the winter mites, because it will take time before your winter bees will emerge and those bees have to be top notch healthy for winter. And after you get them over winter include treating in the spring.
There is one more option. Break the brood cycle for 12 days. lock your queen up for 12 days to get an brood interruption, but you have to check for new queen cells and remove them or the bees will make new queens.
I have seen videos of folks sugar coating bees/hives as well have I seen comments on it. Be careful, sugar coating will kill open brood/ larvae if they get covered in powder sugar.
Also understand how your treatments work. Some treatment may be only active for 2 hours while another treatment does not actually directly kill mites but makes them sterile so they can not reproduce. Also be aware that some treatments will not treat capped brood while another will kill mites inside capped broods.
Do an alcohol wash to check for mites, the sugar testing is not accurate enough. Sacrifice 300 bees to save a hive is not much considering that a queen can lay around 2,000 eggs a day.
Charlotte, thank you for posting this.
Mites are a big problem. Not the only one but they can not be ignored.
I have used the dribble in the fall as I do not own a vaporizer tool to apply OA. I was wondering what you think about using a clean spray bottle and making up the drizzle liquid ban spraying each side of the frame with the bees on it. The dribble gets them very wet and the vapor would envelop the bees in a vapor. Wouldn’t two gentle light sprays on each side be as effective? What do you think?
I dont think so Sharon. There is a fine line between killing mites and harming the cuticle of the bees. During vaporization – the chemical changes as the vapor forms and then cools.
Why is no one using parasitic mites, like hypoaspis mites, to control the varroa mites? Long term protection and no harm to bees.
Interesting idea John, I am sure some of the researchers have considered it. Perhaps, they thought other ideas had better promise. Maybe they will look into this more in the future.
Thank you for taking the time to help inform those of us with less knowledge on Varroa treatment.
Do you have a link to the OA that you prefer to purchase or any recommendations?
Hi Thomas, Legally you are supposed to buy OA that is labeled for bees. But many beekeepers do order quality OA crystals from Amazon.
Hi Charlotte!
this summer i treated with MAQS in august and it was the last time i used MaQs.
that killed one queens and stopped spawn in others hives.
So, i found your site and i bought a varrox.
i wondering if its to late for this year for treating my hives oa vap ? my hives are isolated for the winter. i had plan to treat in october but i just reseived my varrox sooo late
thanks a lot
Julie from Québec, canada
Hi Julie, To the very best of my knowledge its a great time to use your varrox. Because oxalic acid does not kill mites under the brood cap, times of little to no brood are perfect for its use. However, where I live-we cant wait until a broodless time to treat. Go for it!