Mighty Mites and Waxing Poetic

This Bee Babble was started on June 4, 2020, updated on June 21, and probably needs a little more work. When complete, this grey text will disappear.

We had a good Bee Babble Zoom on May 27. Most of the conversation was about treatments for Varroa mites. That will be the gist of this post.

Varroa Treatment

Prophylactic versus Metaphylactic Treatment

We talked a little bit about metaphylaxis vs prophylaxis in the treatments used for Varroa destructor. I have long believed that treatment without testing first, is unwise. I didn’t just come up with this on my own … many of my mentors and most of the scientific and technical references to beekeeping recommend that you test before and after treating. Why would you put chemicals in your hives if you do not have a mite infestation that requires treatment at that time? How do you know whether the treatment worked at all? Testing before and after answers those questions.

I often hear beekeepers, some experienced and many newbees, ask: “Why kill 300 bees to test for mites? Everybody says that we are going to have mites for sure. Why not just treat for them on a routine schedule?” That is a hard question to answer quickly in a “sound bite.”

Somebody pointed out to me that:

  •  In an urban area like Washington DC, your bees will have mites. Mites are known to jump from bee to bee within the hive, on flowers when in close proximity, and at communal sources of water or pollen. Drone bees are welcome in any other nest and they drift quite often, so a drone that is carrying mites is likely to end up sharing them with another colony.  When bees from a strong colony rob a weaker, sick colony, the mites will attempt to the healthier bees and return to their home.
  • If you are treating to reduce the impact of the mites that you know are going to be on your bees, without checking, technically this is metaphylaxis and not prophylaxis.

That having been said, it is really a matter of semantics.

Why Test Before Treating?

You should test at least a sample of  your hives before you treat, so that you can test the effectiveness of your treatment. If you test after you have treated and you have no baseline to compare to, what can you conclude? Let’s assume that you applied Formic Pro and ten days later you measure a 3% mite load.

  • Did you start at 13% mite load and successfully knock down the population to 3%? That is a successful treatment. You still have a mite problem to manage, but no acaricide treatment kills 100% of your mites.
  • Did you start at 2% mite load and your treatment failed and you had a normal buildup of 1% over the course of your treatment?
  • Did you start at 0% mite load and your treatment was unnecessary, but the day after treatment ended your girls robbed out a dying “mite bomb” and totally infested the clean hive. You stressed out your hive with an unnecessary treatment, you still have a mite problem to manage, and it is too soon to treat again with the acaricide of choice.

I try not to lecture on how you choose to manage Varroa mites. There are some management methods that, in my opinion, will work better than others. I am highly sceptical about the effectiveness of some management methods. There are some methods (e.g.: “Do nothing … any bees that can’t survive with mites should be allowed to die.”) that I believe are completely inappropriate for beekeeping unless you are on your own private island. Do not be the beekeeper who relies on “Better lucky than smart” for managing your mites.

However … if you keep honey bees within 3 to 4 Bee Fly Zones (9 to 12 miles) from my apiaries, I have a vested interest in your managing your mites effectively. I can’t stop my healthy bees from robbing your dying bees and bringing home your mites. I can’t stop your infested bees from bringing your mites into the foraging range of my hives.  If you let your bees get infested with mites, you are killing my bees!

Testing For Mites : Wash, Roll, Fork or Slide?

To be written.

  • Comparing the use of counting mites on an IPM Board vs. the Alcohol Wash vs. the Sugar Roll vs. uncapping drone brood
  • Are you really saving any bees’ lives by using the sugar shake instead of the alcohol wash? Probably not … you’re taking a risk that you will let 300 bees live (though I am surprised if more than 50 really do) and you kill your entire hive with a false negative test result.

How to Decide What Treatment to Use When

There is no reason to re-invent the wheel. The Honey Bee Health Coalition has created, and maintains an excellent tool to help you decide which treatment to use. The tool will ask you questions about the following factors: severity of infestation; are you willing to consider a synthetic treatment; is there brood present; do you have your honey supers on; where in the bee population cycle are you; etc.  Once you answer the questions, the list of treatments that match your situation will be presented. You can then click on each one to see the application label, any constraints such as temperature sensitivity, and other instructions for use. It is basically an expert system for mite treatment.

Try it out. Use it. It is updated on a regular basis when new data from reputable science and field experience is acquired.


If you are not sure about your answers, after you have gotten to the end, you can note the results, and then go backwards to change them. This lets you do some “What if?” reasoning. You can use the tool to work out a plan for yourself, such as “I have my honey supers on right now. If I wait to treat until the nectar flow ends and I take the supers off, will that change my options?” (Answer: you bet! Quite drastically!)

My only desire from the tool would be either an aggregation site for reporting of field experience (e.g., how many people report that they used a particular treatment and still had high mite loads afterwards) or a link to the same, if someone else gathers that data. Of course, that is a difficult data set to obtain with “clean data.” Treatments can fail in a multitude of ways. The assessment of whether a treatment succeeded or failed is also difficult. Sometimes you do everything right and your bees get into a “mite bomb” right after they are relatively mite-free. Other times, you might have made a mistake, either in your testing technique or your treatment.

Common Mistakes in Testing and Treating

To be written.

My Treatment Plan Right Now

I will be having surgery very soon, and I’ll be in a cast until July 20. I have a large number of wonderful beek friends who have offered me any help that I need while convalescing. Even so, I don’t want to impose on anyone too much, and with 15 hives or nucs (eek!) in my care, it is a lot to ask of anyone, even if they divide up the work. So, I want to get ahead of the mites as much as possible before I disappear for a month. I have my honey supers on, and they will probably stay on until I can walk again.

We are almost at the end of the window where formic acid can be safely used. Maybe by now, unless we have a “cool spell” it is too late. In July, it will definitely be too hot. So I hit all my “full-sized” hives with a full dose of Formic Pro (both strips). I am going to have to rely on my smaller hives that a combination of the brood break when they were created and the use of mite trapping in drone comb will be sufficient until August.

My own preference is to avoid synthetic chemicals if I can. I treated with Apivar last year because I had high mite loads and I waited until it was too hot for formic acid. The treatment did not bring my mite loads below threshold levels, and I had to treat with formic acid as soon as the temperatures came down.

Warning : This pages are part of my ‘Bee Babble’ series. The content is intended for a specific audience and is subject to my disclaimer

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