Beekeepers are engaged in a battle with a formidable foe – the varroa mite. As guardians of honey bees, beekeepers are challenged with finding effective varroa mite treatments. Whether through chemical interventions, natural remedies, or integrated approaches to management, varroa control is essential. Let’s look at some of the most common ways to treat bees for mites.
A leading cause of colony deaths, there are no easy answers for varroa mite infestations. However, beekeepers must continue to search for the best control methods for this pest of honey bees.
Why Mite Treatments for Bees are Necessary
Finding mites inside a honey bee colony is nothing new. Most honey bee colonies actually have several types of mites in residence. Thankfully, most cause no problem for the bees or the beekeeper.
However, Varroa mites (Varroa destructor) are a different story. These small reddish mites are external pests. They are visible to the naked eye and look like a tiny red dot on the bee’s body.
Mites infiltrate the hive and begin feeding on adult bees, spreading viruses and weakening the bees. Mature female mites enter bee brood cells and reproduce by laying eggs.
Newly hatched mites will feed on the developing bee larva – setting up a deadly cycle of sick, weak bees. These infestations can escalate, leading to weakened colonies, compromised immune systems, and devastating colony losses.
In areas with varroa mites, most infested colonies will die withing 2-4 years without some type of mite treatment plan for the bees.
Key Considerations Before Treatment
Before choosing a method of varroa mite treatment, the beekeeper must face several critical decisions. If only the factors were clear – a decision would be easy. However, that is not the reality.
- not all treatments are equally effective at ridding the colony of the mite infestation
- 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
Varroa Mite Treatment Threshold
How many mites are too many? It depends. (If you thought I was going to give you a definitive answer, you must be a beginning beekeeper.)
Those of us who have been around a while know that most questions in beekeeping have several answers.
But, I do have some guidelines for you to consider regarding when to treat your bees for mites. This involves determining the varroa mite threshold and that is often a moving target.
Regardless of the method used, testing for varroa mites is critical to saving your hives. These involve sticky boards, sugar shakes and alcohol washes.
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Research has provided us with several chemical treatment options for varroa control. These products are generally divided into two groups: hard and soft.
Those considered to be hard chemical treatments are often of synthetic origin. They boast great efficacy but can be hard on the colony and/or have a greater risk of chemical buildup in the beeswax or honey.
Please understand that just because these varroa treatments fall into the hard category – that does not mean you should avoid them.
They have been tested and approved because they work with supposedly little risk to the bees or humans.
Also, varroa resistance to some of these products is reported in the industry. If you choose to use these products, it is important to rotate them.
You must use your own judgement when deciding what to put in your hive – weigh the risks-rewards.
Apistan (fluvalinate) is an older substance used for mite control in honey bees for years. It is an impregnated strip that kills by contact. Strips must be placed inside the hive and then 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.
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.
I have never used this product. Sold as a restricted pesticide in some areas – you may need a veterinarian approval to purchase.
Apivar (amitraz) is a synthetic miticide that kills by contact. Impregnated strips are placed near the brood nest much like Apistan. This chemical was used for mite control for a while 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. Mites can develop resistance. But, some beekeepers report good results with this approved varroa mite treatment product.
Soft chemicals are those treatments that are derived from natural substances. They work without leaving noticeable residues in the wax or honey. Unfortunately, they are not the quick and easy fix that hard chemicals promise.
They are not as effective in mite removal and you must monitor the colony to make sure they worked. With soft chemical mite treatments – you can’t simply put in a strip and forget it.
There are also several essential oil recipes for bees that you can make and try in your hives. Many beekeepers feel that essential oils promote good health in honey bee colonies. But, use care – some essential oils are absorbed through the skin. Wear gloves.
Don’t think that these treatments are weak – many of these natural compounds are strong and should be used with care.
Mite Away Quick Strips (MAQS) formic acid (organic acid) works as a fumigant. Biodegradable treatment pads are placed in the hive for 7 days.
After 7 days, you can remove the pads or not. A plus, you can use Mite Away Quick Strips when honey collection supers are on the hive.
Formic Acid also kills mites in capped brood (many others do not). This is an organic treatment but it is also strong – especially if the temperatures are very warm.
Some beekeepers have reported queen loss or a reduction in brood production. I never had any problems while using this product. But, I always follow the directions on the label!
Extreme temperatures above 92° F during the treatment application may cause colony absconding. In my region, the temperature requirements for some of these treatments were a big problem.
Formic Pro is another option for those wanting to use formic acid. This version has a longer expiration date for the package in case you want to keep some on hand.
It works in the same way as MAQS with some of the same benefits and challenges. I periodically use formic acid treatments in my colonies, they are very effective.
Essential oils are natural compounds distilled from plants. One of the most popular essential oils used for mite treatments is thymol.
There are several thymol products on the market. They do a good job of varroa control in beehives. But, they must be used in a particular temperature range.
How well thymol products work depends on colony strength and weather conditions. Also, check after the treatment period to ensure success.
Apiguard is a gel containing thymol that acts as a fumigant to kill mites. Like most of the natural treatments, this product is temperature sensitive.
Temperatures should be between 59° F and below 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) Api Life VAR is another contender for the one of the best varroa mite treatments.
The product features a green spongy pad impregnated with oils and works as a fumigant. Treatment involves placement of pads on the top bars of the hive – 3 times at 7 day intervals. An acceptable temperature range is between 65-85° F.
Very high temperatures during the treatment period can cause serious colony disruption including bees leaving the hive or absconding.
Used in Europe for years, beekeepers in the United States can now use oxalic acid as a varroa mite treatment. Oxalic acid (Oxalic acid dihydrate-organic acid) is used in two ways for mite control – as a drizzle or as a fumigant (vaporization).
The drip or drizzle method involves mixing OA with sugar water and pouring this over the cluster of bees.
The drizzle method is best used in early Winter or late Fall-when the bees are clustered together. The colony should have little or no brood so the majority of mites will be on the adult bees.
The yearly limit of drizzle applications is 2 per year. This is because the acid is somewhat corrosive to bee bodies. Do not use drizzle treatments in extreme cold or the bee cluster can become chilled.
Oxalic Acid Vaporization – 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 cell.
You need to make or purchase an oxalic acid vaporizers. Be careful when purchasing a wand. You want one that works properly, you do NOT want to be inhaling any fumes. Wear appropriate safety mask etc. Follow the manufacturers directions – read the label.
Using OA in the Summer
Vaporization is my current method of mite control. I believe it is the best varroa mite treatment for bees in my area.
We have a lot of hot weather That makes some of the other natural or organic varroa mite treatments unsuitable during July/August. This is the time that I need to have a healthy hive – getting ready to raise healthy fat bees for Winter.
Because this method does not kill mites hidden inside the brood cell, the southern beekeepers I know – repeat this treatment every 5-7 days for 3 times. Thereby, covering a complete worker bee brood cycle.
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. I don’t argue that point – but for me, it is the best thing I have right now.
Fogging with Oxalic Acid- Should you?
You will hear a lot of information on the internet and YouTube about fogging with Oxalic Acid. We humans are always looking for an easier way to do things. No harm in that -but you may harm yourself or your bees.
Fogging with OA is not approved in the US (at this time). I have not seen any approved research reports that say it is a good idea. I will not use this method for the present.
HopGuard (Potassium salt -hops beta acids)
Potassium salt of hop beta acids (16%) is a natural product made from hop compounds. It is safe to use any time of year – even when honey supers on the hive.
It is more effective when there is less brood in the hive as it does not kill mites under the cap (where the majority of them are).
Beekeepers report that it is messy to work with. Also, beekeepers in my region have not reported consistently good results using Hopguard. Still, you may decide to give it a try in your apiary.
IPM (Integrated Pest Management) Approaches
Chemicals are not the only way to fight varroa. In an integrated pest management plan (IPM) beekeepers use all methods to battle the mite.
One way beekeepers deal with mites is the use of mechanical methods. Using screened bottom boards (instead of solid), causes some mites to fall to the ground and perish.
There was high hopes for the use of screened bottom boards (also called IPM boards) in the beginning but I have little confidence in them at this point as a varroa control. The number of mites removed is just too insignificant.
However, screened bottom boards are great at giving your hive extra ventilation and I think they are worth the effort in that respect.
Powdered Sugar Use
Several years ago, the use of powdered sugar become a popular treatment plan for varroa. Beekeepers would take a cup of powdered sugar and use a sifter to dust the bees.
Removing the hive top and dusting the top bars as bees came up from below. The idea was that as the bees groomed themselves to remove the sugar – more of the mites would be knock off.
Unfortunately, this method has proven to be very ineffective. t does not result in a significant reduction in mite populations (much the same as the use of a screened bottom board).
Few beekeepers bother to use powdered sugar dusting today. But, I must admit that the white bees looked like little flying ghosts for a while – rather cute.
Drone Brood Removal
Some beekeepers advise the removal of developing capped drone bees (the mites favorite host). They use special drone frames to encourage drone production. Once filled with capped brood and developing mites inside, the frame is removed.
Freeze the whole frame, killing the mites and the drone brood is sacrificed as well. After thawing, the frame is put back into the hive for reuse.
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.
- varroa mites are the #1 killer of bee colonies worldwide.
- always – READ THE LABEL – manufacturer recommendations change.
- choose a mite treatment option and try it. If, the first one doesn’t work, try again. After treating, do another mite count. Don’t assume the treatment worked.
- keep a log of what worked or didn’t work in your colonies each year. Good hive records can make beekeeping more enjoyable.
- record your beekeeping year in your beekeeping journal so you will have years of records.
- if you want to go treatment free – find a reputable breeder of Varroa Sensitive Hygiene (VSH) bees
- you must check to ensure that the treatment plan you choose really works for your bees.
Varroa mites are a serious threat to honey bee colonies. They weaken bees, decrease their immunity to other pathogens and spread viruses. Unchecked they result in colony death.
Even though varroa mites are visible to the human eye – you can not rely on visual inspections. Look for signs of varroa infestations such as bees with deformed wings. The real determination requires doing mite counts using approved varroa testing methods: alcohol wash, sugar shake etc.
Yes there are natural alternatives to chemical control of varroa mites. However, they do not work as quick and easy and you must test to make sure they 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.
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. I tell my students in my online beginners class – you need a mite mite control plan. As the industry strives to breed bees with more mite resistance we use what we have.