Updated: Mar 4, 2020
For the full article with pictures and supporting graphs, visit www.BeeResQ.com (removed for blog post)
Thermal Treatment Review
Mites, Small Hive Beetles, and MORE??? :-)
Beekeeping Stories: An adventure in Integrated Pest Management
An article and review by Mike Immer for www.BeeResQ.com
Please be sure to get permission from and credit the author and source when
Special thanks to Sophia A. Immer for some assistance making graphical sense out of
my junky spreadsheets! (removed for blog post)
Thermal treatment equipment and methods vary. The thermal boards from
www.beehivethermalindustries.com are simple and require little to no custom or
Thermal treatment on 30 test colonies showed the greatest effectiveness on both
varroa mites and small hive beetles (SHB) on single brood box configurations.
Thermal treatment was still effective for varroa mites on double deep brood boxes
configurations but was less effective for small hive beetles (SHB).
Thermal treatment was more difficult and less effective for varroa mites and made
almost no difference for small hive beetles (SHB) in triple deep configurations.
Additional, more anecdotal information offered: general health and hardiness of
bees observed to be better and support the proposed additional benefits of reducing
the viral and bacterial load bees may be experiencing with mites being the primary
vector for the additional diseases. Testing to continue on this topic.
Pros: Kills mites on the bees, in the hive, even under capped brood
Kills or forces out small hive beetles (SHB)
Less safety equipment is required/more comfortable
Safer than oxalic acid sublimation/dribble
More studied and proven than essential oils and powdered sugar methods
Less temperature dependent than some treatment methods
Can be used with supers
Durable and reusable
Can be integrated with other pest management methods if needed
Length of treatment ensures impact on mites as foragers come and go*
Affects mites on bearded bees with temperatures that kill or sterilize mites
Recent studies indicate that heat can also reduce viral and/or bacterial loads
No need to buy and store harsh chemicals or worry about expiring products
~$350 US per unit
Cons: Length of treatment (roughly 2.5-3 hours) and yes, listed as both pro and con
Requires monitoring for 15-30 minutes until treatment temp is reached
Requires power (nearby outlet or generator)
Only available for Langstroth style 8 Frame, 10 Frame and Nucs
Custom bottom board required to treat plastic/foam insulated hives
Recommended operating temperature minimum 70 degrees Fahrenheit
(Meaning most treatments done in daytime when foragers are out)*
Effectiveness varies based on configuration of hives l
(Meaning most effective on singles, least effective on triples)
Doubles and triples often require tape over any gaps between boxes
~$350 US per unit - and yes, this is listed as both pro and con
*Note: Reiterating the biggest complaint about the process and product, the
treatment time. This may actually be a positive in regards to overall effectiveness.
Most foragers will be making trips back into the hive to deposit any gathered
resources over this period of time and will be exposed to the raised hive
temperature. The temperature to sterilize mites is actually lower than the full
treatment temperature, and less exposure time can still effectively reduce or
eliminate mites in a given hive/colony.
Returning foragers may also beard up with the other bees trying to regulate the hive
temperature, and thus be exposed to temperatures that can kill or sterilize mites
they already had, or those they may have picked up while robbing out a collapsed
hive, open feeding, or just being out foraging in the trees, flowers, etc.
Records/Data: See my somewhat rudimentary spreadsheet data and cost
comparison at the end. One or two hives being tested wouldn’t be a large enough
sample, so I used 30, in the same yard. Further, more scientific studies could
eliminate more variables by standardizing further and providing a control. (removed for blog post)
Disclaimer: I am not a scientist or a professional researcher, data analyst, or even a
spreadsheet guru. I’m an “ok” writer I suppose, but I know there are errors here and
there in this article correcting would have put publication of this information off
EVEN LONGER. The curse of a perfectionist with very little time I guess!
That said, I know there are unaccounted for variables, and likely anomalous data
due to my own terrible handwriting, the weather, etc. J But certain trends and
generalities can be gained from the data I’m offering as it relates to the small scale
testing that I did on thirty of my own colonies in the summer and fall of 2018.
Thumbnails (below) are of the larger graphs at the end of the document: (removed for blog post)
The Rest of the Story - for those that like to read
First of all, I am not what you would call a strictly, treatment free beekeeper.
By strictest definition, treatment free beekeeping advocates discourage ANY type of
activity that intervenes in the process of bees developing their own survival traits
against pests like varroa and small hive beetles. Some would argue that anything
beyond observing them in the wild could be considered intervention. So I won’t get
Although I applaud treatment free or chemical free beekeeper’s determination and
intent in some ways, and I LOVE the idea of treatment free beekeeping…I like the
idea of keeping bees alive even better!
Even so, I try to keep a “no judgment” attitude in my little bee company as I try to
help whoever I can, without condemning “mite bombs” and the increased potential
for small hive beetle proliferation, and spreading of other diseases etc.
I just try to be as responsible a beekeeper as I can be, and take care of my bees, and
my customer’s bees, as well as I can.
That said, and even though I use things like Apivar, oxalic acid sublimation/dribble,
patties, test other methods etc., I DO like to limit the use of harsh chemicals when I
In fact, I tend to favor more natural and organic treatments whenever I can… IF they
So, in thinking about this mysterious new thing called “thermal treatment” what
could be more natural and chemical free than strait up heat? Right?
I’ll go ahead and risk sounding (unintentionally) like a review of the specific type of
thermal treatment equipment I tested, but this article is more than that.
Hopefully I will be able to relieve some of the immediate concerns beekeepers seem to have beyond the general “newfangled-ness” (if that’s a word) of these computer
A lot of beekeepers have never heard of thermal treatment.
In fact, I’ve received lots of private messages about this topic, so thought I’d go
ahead and write up my experience and elaborate a bit for whoever is interested.
When I first came across thermal treatment, I had NO IDEA what it was, how it
worked, it’s intended use etc. other than it was a relatively new and chemical free
alternative treatment for honeybees to rid them of the nasty little varroa mites that
have been causing such difficulty and disease.
It turns out that the bees themselves do a version of “thermal treatment” when they
swarm, raising the hive and their own body temperatures before they go, etc.
Fascinating, right? Did you know that? I didn’t until I started my research!
I did a ton of reading, and it turns out that the concept isn’t necessarily new, but
overcoming some of the challenges during the studies and finding a way of
simplifying the process IS new.
To boil down a LOT of research, some of which was conducted in other countries,
thermal treatment simply involved heating bees up to determine at which
temperatures mites were affected, and at what temperatures would the bees, brood,
wax, queen, etc. be able tolerate?
You can imagine how many bees “gave their lives” in this type of research. It’s kind
of sad to think about.
You can imagine, there were significant difficulties encountered in rounding up
bees, moving them, containing them for treatment, building cabinets for treatment
and monitoring, and then putting survivors back, and determining queen viability,
managing variables, laboratory versus field studies, etc.
Moreover, there was lot of measuring and recording of data to determine what
temperatures and timeframes were required to kill mites in various states and
various places within the hive. For instance, finding ways of killing mites under the
capped brood, where they are protected from many other treatments!
By the way, this is the real breeding ground for varroa mites, that many other
treatment methods don’t reach. This one very good reason that oxalic acid (OA)
vaporization (more accurately called sublimation) and fogging aren’t very effective,
at least when brood is present! That is also why several treatments are necessary.
The every four days, or every seven days, for three or four treatments with OA? That
is intended to get into the cells that were capped, and hatched, etc. over the
treatment period! That may be something else you didn’t know too!
So, before we get into too much detail, I think the simple goal of all of this, beyond
healthier bees, should be stated:
Use heat to destroy/control mites, and have healthy and productive bees.
Without going into the “law of unintended consequences” and a bunch of other stuff,
let me outline some of the reasons I landed on one particular product to test with.
1. I didn’t want to utilize ANY non-standard beekeeping hive equipment. If it
required custom frames or foundations, I had no interest in trying it.
2. I wanted use ONLY standard Langstroth deeps, mediums and even a few
shallows, in ten and eight frame configurations as these are the most
common, and would provide the best test for my own purposes based on
what equipment and bees I had available.
3. Portability is important as I also didn’t want to have some kind of bulky
enclosure or cabinet to move around, or a process that could only be used at
night, or anything like that.
Why? Like most beekeepers, budget always plays a role. All of my equipment at the
time consisted of standard, Langstroth deeps, mediums, and shallows, with a mix of
plastic frames, plastic foundations, wooden frames, and even some foundationless
frames. And I also had very few telescoping lids by this time, as I had switched to
After doing some looking, I chose the www.beehivethermalindustries.com “Mighty
Mite” thermal treatment boards.
I spent a lot of time at their website reading through their documentation before
deciding to go this direction. The information they shared matched up pretty nicely
to other studies I’d read, and even used some of those studies as sources.
Since I had both eight and ten frame equipment, I went ahead and ordered one of
each. This would allow me to treat two hives at a time, which it turns out was hugely
beneficial to me as I had already determined I wanted to test thirty hives.
This particular piece of equipment met my needs for simplicity, no custom
beekeeping woodenware, etc. and it was simple to install.
But there were (and are) some requirements to consider.
1. You need a power source, either a standard outlet nearby, long enough to run
extension cords, or a generator.
2. You need to make sure the ambient temperature is 70 degrees or higher.
3. You may need some tape for any gaps, and an extra super to set on top of the
provided foam lid to hold it down while providing adequate ventilation.
4. Notably absent from these requirements? Chemical resistant gloves, eye
protection suitable for fog/vapor/sublimation, and a respirator.
Since I was running mostly singles, I started with a couple of those and decided to
test it’s effectiveness on the doubles and triples I had, last. Since customers had been
asking, and I was investing the time and money into testing these devices, I was
determined to keep records as well as I could.
(Assuming my chicken scratch, glove and wind hampered notes can be trusted, I’ll
provide what I was able to translate into spreadsheet data at the end!)
It’s important to note that the following experience as a first time user of thermal
treatment, although common, isn’t necessarily representative of a typical treatment.
I’m just relating what I did, how I did it to some extent, and why.
But it makes for an entertaining story that can save time for users of this product
who, having read this, will know better what happens, and what parts of the process
will continue on WITHOUT the intense scrutiny I’m describing.
And yes, I did a mite wash and counted nine on the first hive prior to treatment.
As you can imagine, I was very cautious with my first treatments to be very sure I was doing this correctly. And I remember, my goal was to test this process, so starting with a “before” alcohol mite wash was an important step.
I reviewed the instructions and got to work.
I slid the thermal board/heating plate into the fully open entrance easily. It fit nicely and sat solidly on the bottom board, covering the screen on the first hive. (I had a mix of both screened and solid bottom boards.)
Following the directions closely, I placed the sensor on
top of the middle frame of the bottom brood box, which was easy enough given that
I was starting with singles. Then I made sure the connection to the control unit was good.
I put the provided insulation board on top instead of the migratory lid, and then placed an empty medium on top of the foam insulation board to hold it in place, and placed the migratory lid back on top of the empty super, leaving it gapped, or open by a couple of inches to make sure it was well vented. And since my first test was on a single, I didn’t have to worry about taping/sealing any gaps between brood boxes etc.
I put the specially provided entrance reducer on the front. It was designed so that it
had just enough room for the cable to the heating element on one side and only
enough room for a bee or two at a time to make their way in and out of the opening
at the other side.
This special reducer was intended to keep the heat in and make it harder for
the bees to work against the process while the hive was getting up to
Nervously, I plugged in the control unit last, and three lights blinked as the
computerized controller did a “Power On Self Test”. I was one button push away
from starting the process. So, I gave it one last look and started it up.
What was going to happen??? Would all of my wax melt? Would my bees pile up dead? Would my queen abscond, stop laying, or worse let, lose viability or die???? Scary stuff, right? :-)
I watched, intently while the blinking blue light indicated it wasn’t yet up to the correct temperature.
A few bees started piling up a little at the much smaller entrance as it took fifteen to twenty minutes to switch from blinking blue to blinking green
indicating the hive had reached treatment temperature.
I pulled the entrance reducer out a couple inches and stood back to watch…and
The green light blinked red a few times indicating that the temperature in the brood
nest had reached a tenth of a degree higher than the target, and the thermal board had turned off and stopped heating for a while. As the temperature came back down
to the ideal 106 degrees, the green light resumed it’s blinking.
The beard on the front of the hive got bigger, and bigger as more and more bees piled out in a futile attempt to lower the hive temperature.
And more and more foragers were coming in to deposit the resources they had gathered.
It made sense on seeing this why ventilation is SO important. Imagine how much oxygen the bees use to try and cool down their hive into the normal range! If the hive was sealed too tightly, asphyxiation would be a risk!
This cycle continued…and continued…and continued…for two and a half hours!
That’s a LOT of time, right?
But not to worry! I was only sticking around for the full cycle because it was my
first time using it.
As I gained more confidence and experience I was able to start the process, and once
the entrance reducer was pulled away, I could walk away, go do other things (like
start a second hive’s thermal treatment process, and just let the treatment complete
on it’s own.
Please note that it is CRITICAL to make sure the ventilation is correct, and to
remove the entrance reducer once the hive reaches treatment temperature. So set
an alarm on your phone or something! (That’s what I did).
While observing the process, and watching the bees beard more and more, I also
noticed something else that was fascinating…
Small hive beetles were LEAVING the hive, right out the front entrance, and
right into direct sunlight!
But more about SHB later.