Some observations after my first OA vaporizer use.

I decided to use a white abitibi board (it is used for siding or walls and
runs about $15 for a 4'x8'x1/8" sheet) for my mite count. I cut it into
1'x2' boards. It is easy to slide into the hive and remove and the mites
are easy to spot.It has a white shiny plastic coat on one side.

Lesson 1- put the board in after treatment. I wanted to see if there was
any drop immediately after treatment and could have done so by inserting
the board after removal of the vaporizer, but decided to have both in at
the same time to see if there was any immediate mite drop. Even with a
concerted effort to keep the heated pan down, the extra 1/8" elevation put
it close to the frames and I got some wax melt and burning. No problem
after that with the board out. There were no immediate mites.

But I made sure, after my first trial, that I put the towel I used to close
up the entrance under the vaporizer shaft so it was angled down inside the
hive and away from the frames. I am going to measure out a "shim" to put
under the shaft so it will be pointed down and I can just lay the towel
that closes up the entrance over everything which is easier.

Lesson 2- The time it takes on the first hive is not the same as all that
follow. So the dry run to measure the time is for cold equipment. In my
case it was about 2 min 45 sec. 2:30 seems to be the norm.

In real life, when you remove the vaporizer after waiting a minute, and
reload it, the OA will start to liquefy. So you really need to  measure
that time too. I did and it is about 2 minutes instead of the 2:45.  I took
my time between the two vaporizations to make it as close to what would
happen in the field. Also it was a cool day, so it was a "longest case"
scenario.So if you just stay with 2:30 you are just heating equipment and
doing no vaporizing for 30 seconds, which is a long time for something to
go wrong.

Lesson 3- BTW, have you noticed that I am discovering the obvious? The
problem is that there is little out there in the US about vaporizers and
some of it is wrong. Anyway, the times are too long for real use. You
should subtract at least 15 seconds off your time from power on to power
off as the tool is still hot enough to complete the vaporization even with
the power off. The normal time between power off to removal is 1 minute,
but just add 15 seconds and all is well. By not leaving it on, you are not
running up the temperature and possibly causing damage both to the tool and
frames near the tool.(See lesson 2.)

There seems to be some arbitrary rules with OA vaporizers, such as the 1
minute wait rule. My guess is that it is for safety so we idiots do not
remove a smoking tool. Another is to keep the entrance close for 10
minutes after treatment. Again my guess is for safety rather than increased
efficacy. Some don't bother. Some procedures have you leave the tool in the
hive for many minutes to cool (10 seems the norm). Again, this seems more
for safety than any other reason. I did with my first trial but will not
for future ones. But you need to wear that respirator!

So what were my results? They confirmed my hive inspections and alcohol
wash which was that there were no mites in my two test colonies. I checked
the boards after one and two days with zero for one hive on both days and 4
mites for the other hive.So the OA gave me better results as to the status
of the colonies than did my inspections. Plus it was easy, took less time
and near zero disruption of the colonies. And it measured all the sunning
mites (getting their burn before going into the cells, also known as
phoretic).

I wondered about such low mite loads but learned that, at this time, they
are low around the State. So my readings are fine.

The next stage of my test will be in August when I do the multiple day
treatment (4x at 7 day intervals) as well a one hive with MAQS as a sort of
control. At the end of the OA treatments I will OA the MAQS hive to see any
difference in mite drop.

I do believe that OA vapor is a great mite treatment tool. But I also
believe that sometime soon there will be a vapor incident, since it is
great for the bees but really dangerous for the beekeeper.

Bill Truesdell
Bath, Maine

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