Hello my name is Doug Somerville, I'm a technical specialist with the NSW Department of Primary
Industry for honey bees.
My responsibilities are education, research and extension for NSW.
What I would like to briefly give you a talk about or present to you are the results of
a research trial we ran over 14 months looking at screened bottom boards on beehives.
There is this belief that screened bottom boards, something like this, is bad for the
bees because of the added ventilation that the bees have to deal with in relation to
the temperature control of the beehive.
What I set out to do was to demonstrate whether that is actually the case, whether that screen
or ventilated bottom board does impact on the productivity of the beehive.
So what we have got here is a normal or conventional bottom board, you can see that it is solid
with cleats underneath and rises up top and entrance here.
It's just your normal standard bottom board that the majority of beekeepers utilise.
Here we have a screened bottom board, there are different types but the same principle
applies.
The gap there that they've got is about 3 millimetres so it prohibits the movement of
bees through these screens.
Bees cannot go through the screens, but a lot of rubbish can and particularly Varroa
mites if we were ever to get them.
Here I have got a hive for a foundation that gives you the indication that its got a screen
on the bottom of it.
So what we did is we set up 60 beehives, we equalised all the populations, we re-queened
them all so they had all sister queens and we managed those hives for 14 months.
We moved them around four different locations in the state, in the south of the state, different
climatic zones from the coast, the west and the tablelands, extracting honey and gathering
a lot of data in relation to variability between hives and treatments.
The end result was that the actual screened bottom board, this particular design, produced
15% more honey than a conventional bottom board.
The reality is that is not a major significance but what it does clearly demonstrate, this
is the ultimate result of this trial is there is no difference between solid bottom and
screened bottom.
Bees are quite happy, in a range of climatic zones, existing with ventilated bottom boards
and that was the essence of the trial.
So one of the uses for a screened bottom board is to monitor mite populations in a hive to
determine if the hive needs treatment or not.
So this screened bottom board for instance has been modified so a tray can slide underneath
to catch any mite falls.
In that tray you could place a sticky mat or Vaseline or something and leave it under
there for 24 hours and then you pull it out and count the number of mites trapped in the
tray to determine if the colony needs treating or not.
Thus far Australia does not have Varroa mites, so we are in a privileged position, but if
we ever did this would be a very useful tool to use to monitor the mite populations.
Here I've got a card that's literally covered in Varroa mites, this particular example came
out of New Zealand a very heavily infected hive.
But that card would be sitting on the base of a tray, the colony in this case has probably
been treated with a miticide, all the mites have fallen through the screen onto the sticky
mat underneath and it has given you an indication of the mite population in the hive.
So it is a very useful tool to measure mite populations in a hive and determine when or
if treatments are necessary.
The full copy of the report is available on the Rural Industries Research and Development
Corporation website.
It's called Screened Bottom Boards and you can download it for free or you can pay for
a printed copy.