Adrian M. Wenner wrote:
[....]
>    HYPOTHESIS:  I believe that we can expect that those colonies with a
> high propensity to swarm will be the ones most likely to survive varroa
> infestation [....]
 
>    Implications for beekeeping:
>
> 1)  One can expect swarming rates to increase.
>
> 2)  A new protocol for beekeepers to follow might be for rather frequent
> colony division (artificial swarming) as part of their management program,
> with later uniting of colonies once the mite reproduction cycle has been
> broken.
 
An interesting thought.  It ties in nicely with a biotechnical varroa
control technique discribed by Johan Calis on Bee-l last year which
combines drone trapping and colony division.  I could just quote the log
reference (LOG9504) but, since I just looked it up to refresh my memory,
I thought it was worth reposting.  It's too complicated for a large scale
beekeeper but for people like me it could be quite practical and I intend
to try it next year.
 
-------------------------------------------------------------------------
Date:         Fri, 28 Apr 1995 12:30:33 +0100
From: johan calis <[log in to unmask]>
 
[....]
Briefly the method:
We combine treatment in two colonies. During early spring (now) we put drone
comb foundation in our colonies and remove this after capping (two drone combs
on the edges of the brood nest are placed and replaced after capping). This can
be combined with regular inspections. This in fact is the original drone-comb
method which works well but not well enough. Generally it can be assumed that
at least the growth of the mite population can be prevented with drone comb
removal in a queen right colony with brood in all stages.
Than comes the period of swarm prevention. We work in the colonies weekly at
the same day.
Week 1
Colony 1 & 2. We place a drone comb in the middle of the brood nest, because we
want the queen to lay eggs in it during the following week.
Week 2
Colony 1: we remove all the brood except for the drone combs with larvae and
put this brood into colony 2. In this broodless colony 1, all mites are now on
the bees and can be trapped with the drone combs that are being capped. This
colony is mite'free' after one week, and is being used to produce drone combs
with larvae for the other colony. Therefore we also put an empty drone comb
next to the drone comb with larvae.
Colony 2: We put the queen together with at least one drone comb with larvae
and an empty drone comb in an otherwise broodless super on top and separated
with a queen excluder of the other supers with all the brood of colony 1 & 2.
Week 3.
Colony 1 : In most cases the drone brood will be capped and can be removed (but
the drone brood will not emerge for at least another week and can therefore
remain in the colony when still a large portion of the drone brood cells are
open). The colony is now clean. The newly produced worker brood of colony 2 is
removed from there and put into colony 1 (brood younger than 7 days is still
not being invaded by mites, so this brood is and (since it's being tranferred
to the already mite free colony 1) remains mite free!). The drone comb with
larvae is being replaced by an empty drone comb.
Colony 2 : The top super, with the queen, is taken from the colony and placed
on a bottom board. As mentioned the young worker brood is transferred to colony
1 and this artificial swarm is, containing at least 7/8 combs of bees, the
queen and at least one drone comb with larvae, is being placed on a other stand
to prevent the uncontrolable loss of flight bees. That leaves colony 2
queenless with brood aging at least 1 week. We remove all (urgency) queen cells
if present. In this colony you can now breed new queens by e.g. offering larvae
in queencups.
Week 4.
Colony 1: The drone comb with larvae is replaced with an empty one.
Artificial swarm of colony 2: The drone comb can now be removed and similar to
colony 1, week 3, this artificial swarm is now mite 'free'.
Colony 2: The capped brood ages at least 2 weeks. A drone comb from colony 1
with larvae is placed into the middle of the colony.
Week 5
Colony 1: The last drone comb with larvae is transferred to colony 2.
Colony 2: Young queen emerged from queen cell. All the old brood is now
emerged; all mites are now on the bees. The drone cells can now trap with a
high efficacy the mites from the bees .
week 6/7
Colony 2: The capped drone combs have to be removed and than also this colony
with a young queen is mite 'free'.
 
We started with 2 colonies and now we end with 3 colonies.
 
Capped drone combs can be reused. To clean them cut the caps away with a
breadknife, shake the drone pulp out (chickens love it!), clean with water with
a handspray and let dry carefully.
 
This is briefly the method as we use it, but many variants can be considered.
Important rules of the thumb are:
-You can only trap mites when they are on the bees. You have to trap in
broodless colonies or colonies that have brood younger than 7 days.
-You need 500 capped drone cells per kg bees (10.000 bees) to trap more than
95% of the mites in a broodless colony.
-Brood younger than 7 days is not yet invaded by mites.
-Never let drone combs emerge, than you will be breeding mites instead of
trapping them.
-Also natural swarms of unknown origin can be de-mited with a comb with drone
larvae.
 
Good luck!
 
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Malcolm Roe            [log in to unmask]
                       Hewlett-Packard Laboratories Bristol
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