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Why 2020 mites were harder to control (To treat or not to treat is the wrong question)

Updated: Feb 15, 2021

Why 2020 mites were harder to control than other years: To treat or not to treat is the wrong question…

By Mike Immer,

Get comfortable. This post turned into a little more of a meandering ‘story like’ article…but I got tired of re-reading it to try and consolidate it…so people who enjoy reading…enjoy. Those that don’t will get the idea pretty quickly. 

The correct question is: To test or not to test? And the answer will MOST frequently be…TEST!

Why? Understanding the condition of your bees is critical to avoid over treating as much as it is critical to avoid under treating.

If you treat prophylactically (as a hobbyist) on certain dates, at certain times of the year, using whatever method is frequently used, you could end up with a big miss when something like…I don’t know…THE WEATHER changes!

New, and intermediate beekeepers usually lack the experience to determine through other means that treatment is necessary. This means you/they COULD be contributing to the development of pests and diseases that are resistant to common (and least expensive) forms of treatment.

Testing can help you be sure you are not unnecessarily exposing healthy, low pest/disease load colonies to unnecessary levels of chemicals (and/or stress). And it can save you MONEY in an admittedly expensive hobby/business.

Testing can also help you avoid issues nearly EVERYONE in your area (and mine - Kansas City region) had this year with late increases in mite levels which is resulting in heavier than normal winter losses.

How? As your testing may determine a low mite level, and therefore no need for certain types of treatment, so too might testing show an “above expected” mite level, late in the season…you know…after fall treatments are “typically” done.

You might recall that summer lasted into fall, and fall lasted into winter in 2020. (And why wouldn’t it in such a crazy year, right?  ).

Therefore, the brood cycle wasn’t disrupted as early, despite shorter days. Meaning? Some types of treatments were ineffective, or needed additional treatment cycles to be effective.

Another way to say it? Temperatures were higher, later into the year, meaning brood (where mites grow) continued being produced AFTER most scheduled treatments. Or there was capped brood DURING most fall treatments…meaning?

MOST methods of mite treatment are ineffective under capped brood, and likely ended prior to brood cycle winding down, or were not repeated based on weather and mite counts… as they SHOULD HAVE.

Why do you say should have? How do you determine this? Weather and population…

For example, we were seeing higher than normal populations into the late fall and were able to determine mite counts were higher and treatmets were less effective than they had been in previous years. Treatments should have been continued or considered as late as October/November…some might argue into December. 

But wait, we are beekeepers right? Won’t we argue about anything anyway? LOL

So, the long and the short of it, in my humble opinion, is that we need to be spot checking our apiaries (if larger yards) or our hives (for smaller/hobbyists) more thoroughly, and more often, so long as their population and other conditions warrant it.

To make a short story longer, I’ll offer some more thoughts, insights, and examples.

An already weak hive, with low population, exhibiting signs or symptoms or other issues (*such as SHB, wax moths, ABPV, BQCV, CBPV, DWVA, DWVB, IAPV, LSV, Trypanosomes, Nosema apis/ceranae) should be treated accordingly, without necessarily euthanizing a few hundred bees.

*If the preceding “alphabet soup” of diseases and pests doesn’t mean anything to you, please work with a more experienced beekeeper that can offer suggestions on an appropriate course of action and even assist you in getting bees tested in a lab.

…ok, OK! Here’s what all of those abbreviations stand for according to the results and abbreviations used the last time I sent bees to a lab:

SHB = Small Hive Beetles – a pest that normally only appears and ‘slimes’ weakened hives

WM = Wax Moths – a pest that normally only appears and webs/cocoons in weekened hives

ABPV = Acute Bee Paralysis Virus

BQCV = Black Queen Cell Virus

CBPV = Chronic Bee Paralysis Virus

DWVA = Deformed Wing Virus Strain A

DWVB = Deformed Wing Virus Strain B

IAPV = Israeli Acute Paralysis Virus

LSV = Lake Sinai Virus

Tuniv = Trypanosomes

Nuniv = Nosema both apis and ceranae

If a hive seems otherwise healthy, has a good population, please don’t be afraid to examine them closely, conduct a mite count (I prefer alcohol/soap/washer fluid over sugar roll or sticky boards) and remember WHY you are looking at mites.

Note that the mites themselves aren’t necessarily killing the bee. Rather, while feeding on the fat body of the bees, or when they are done feeding, they are or have weakened the bees. The mites have likely become a vector for viruses/disease in the weakened bees, before hitching a ride on their way out of the hive as the colony collapses/absconds etc.

*Think about how ticks affect mammals and introduce disease. Similar, for mites on bees except these mites feed on an organ within the bee called the “fat body”.

And that is when many less experienced beekeepers see spikes in SHB, moths, and later in the season, absconds, collapses, population declines, lacking healthy winter bees, starve outs, low population freeze outs, or other forms of dead outs.

Those remaining bees “bailing out” of a hive as it collapses will drift over a mile and find homes (and drop mites) in other healthier hives.

Once it’s too cold to fly, for real, those bees that drifted, dispersed into other hives, with their little tag along mites may like their new home, and are going to stay put or work from their new home for a while. And as they do so, it gets later and later in the season.

And that, of course, is when winter is at it’s darkest, and sometimes the cold as it at’s worst, and the moisture in the hive can becomes deadliest, even with a decent cluster.

I’ve seen hives test with extremely low mites, spike to an extremely large number of mites (more than what hatching brood would account for) even a few days after a treatment.

So, as you reflect back on last seasion, you may not have been battling your own hive’s mites.

You were battling your neighbors mites down the road…and your neighbor’s neighbor’s mites, and so on, as their hives absconded and drifted. Fun stuff, right? 

This is why a lot of beekeepers do get upset about less diligent beekeepers, or hobbyist that fail to properly care for their bees.

Don’t get too defensive.

I’m not offering anything here other than some explanation and my own theory on why 2020->2021 winter was so transitional, caused higher than expected losses, and why some newer beekeepers that were getting a little overconfident might be licking their wounds (and buying more bees this spring).

It’s exceptionally cold right now as I finish this post. Like negative temps, after a night if double digit negatives, and theirs several inches of snow, almost white out conditions, and yes, even as a seasoned beekeeper I wonder how well the bees I’ve kept at home in Missouri are faring (compared to those I sent south).

Beekeepers almost always get nervous this time of year! This, is when you see the social media posts go nuts about winter killing bees.

And that is also when my phone starts to ring, my website starts to ping, and I start to worry that I might run out of bees for customers in the spring.

Yes, I sell bees (nucs mostly), and this cycle CAN be good for business.

But I ALSO sell queens, and I’d much rather help you keep your bees healthy, teach you to split and manage your apiaries better, and help you avoid getting discouraged! We need bees!

Just remember, bees drift, abscond, swarm, and take diseases and pests WITH them. (How do you think they got here?) 

Why does that matter?

Well…that’s when YOUR problems…become mine…and become the problem of every other beekeeper within a mile of a mile of a mile of a mile of a mile (you get the point) of a colony that fails, absconds, swarms, spreading their issues further and further.

It’s kind of hard to isolate/quarantine/restrict an insect that forages for miles, right?

But wait, what about treatment free beekeeping?

Oh boy, I’m not taking the bait here in this article. I’ll just share this extra little bonus story/example (in my already rambling forum post/article) LOL:

I have customers that keep bees for the sake of keeping bees, fully intending on sending swarms out into the world. Again, no judgement.

But as I ask and assist them, and I’ll ask you too… Can we please make sure that the bees we send out into the world, to your neighbors flowers, trees, and hives, are as healthy as possible?

I’ve had customers that wanted to do exactly this. We treated thermally, and with more common methods, and he got to enjoy seeing his hive swarm and start a new queen.

Now, before other experienced beekeepers go nuts and start commenting, let me just say, all other aspects of the situation WERE discussed, along with potential damage a swarm could do to homes and structures, etc. And they were going to do this either way!

This way, at the end of the day, at least we knew that the bees leaving his hive were as pest and disease free as we could make them.

And I’m hopeful another lucky beekeeper within a mile or two was very pleased with the swarm they retrieved! She was an awesome queen! That colony produced over a hundred pounds of harvestable honey the first season…from one of our nucs!

(Yes, I should’ve grafted off of her myself!)

PS. Edits, corrections and suggestions are welcome. Shares, reprints, reposts are all totally fine with me, just please give credit and include my website ( when doing so.

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Feb 15, 2021

A comment came in via email asking if they were doing something wrong by doing an OA sublimation in January without testing first. My thoughts were: no, not necessarily. Referring back to my original post I offered an exception early in the article for other indicators impacting this. :-) population being low in January would be one of those things to consider. Another is knowing why you are treating. Did something come up that left you less confidential fall/winter treatments? So there are lots of variables to consider right? :-) Here’s another thing to consider: Cluster density. Will an OA sublimation (vaporization) get to all of the bees if they’re are tightly clustered? I like to see them warm enough…


Feb 15, 2021

Another excerpt from our conversation: Lol I really like your theory as it makes a lot of sense. Even if you consider varroa lesser or not a vector, you’d have to give credence to the penetration required in order to feed. The drift thing is fascinating. The compromised immune system fits into really any case of succepability.


Feb 15, 2021

From Darwyn Flynn (really good thoughts imho): Good blog post. I wanted to throw a twist in for you to ponder. I’ve sought to validate what I call “theory” for about 6-8 years. “Varroa is a vector for viruses”. I found one euro study that dissected varroa and tested to discover DWV. The amount was very small relatively speaking. At The Texas bee lab, I ran into a candidate, now PHD, who curiously tested 12 different ant species commonly found in bee yards in Texas. All carried DWV. These viruses exist in the bee world. Varroa feed on fat body which is tied to the immunosuppression system. Darwyn’s therory - Bees vector their own viruses. Varroa merely comprises the immune…

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