On 18 Dec 97 at 1:49, Sid Pullinger wrote:
>
> Whilst I do not in any way dispute the claims that bee breeders have
> produced resistance to tracheal mites by selective breeding I am
> very puzzled as to how this may come about.
 
I think we are confusing a number of issues in this post, and
possibly the only way to clear up the problem would be to recount
what we had to do to achieve T-mite resistance.
        We had been extending our yards for some years by buying queens from
a variety of Ontario breeders, as the yard we had obtained had
started inbreeding. The previous owner didn't worry too much, and
as a result the egg pattern had started to disintegrate.
        Dr. Nasr's program came at just the right time for us, so we
isolated 15 hives all unrelated to each other. With the program we
tested each hive for resistance or susceptibility to T-mites. Out of
those we found 5 which were susceptible and ranged up to resistant.
We removed the bad, some of which we culled, and bred from the top
ones. After 3 generations the quality of resistance didn't change.
        Basically resistance is natural, there are no changes made to the
bees. The reason for resistance is not fully understood, some are
resistant, some not, all we have done is selected the best.
        Regretfully the North American method of bee keeping is maintaining
susceptible bees. Whereas in the UK the bad were allowed to die,
mainly because in the first instances there was no treatment for
T-mites, here they are medicated and therefore perpetuate. This of
course keeps the problem rolling, as these bees mate, even with
resistant queens and weaken the resistant strain.
        As I have said many times, T-mites are still a major problem, they
are just masked by medication for V-mites.
        The only true way to determine T-mite resistance is the assay test
where young bees, less than 24hrs old are inserted into a T-mite
hive. One week later they are found, sliced and examined under a
microscope. Now you can count mites, larvae and eggs. But how many
even take the time to send bees to the lab for checking? The average
bee keeper thinks it's more cost effective to slap a grease pattie
on and forget it!!!  As I said before perpetuating the problem.
 
> test carried out on 120 colonies only two showed slight traces of
> mites. The other had found a colony with around 100% infestation
> "tracheae absolutely black with mites" and was treating with grease
> patties.
 
 As I said perpetuating the problem. Wouldn't a better solution be to
re-queen with the first guy's stock?
 
> wintering bees this does not have much effect in a short winter.  If
> you live in an area where the winters are long, hard and unbroken
> and breeding is delayed. the situation changes and you can well have
> the old bees dying off faster than the young are produced.  Thus you
> have an apparently healthy colony in midwinter collapsing in March
> or April.  In such a situation I would accept that autumn testing
> and treatment would be necessary.
 
I think the best analogy would be to ask. How well do you perform
when your lungs are full of junk? I had double pnuemonia a couple of
years ago, almost killed me, what does the same thing do for your
bees?
        Comments?
 
*******************************************
The Bee Works, 9 Progress Dr, Unit 2,
Orillia, Ontario, L3V 6H1
Phone/fax  705-326-7171
David Eyre, Owner.
http://www.muskoka.net/~beeworks
e-mail <[log in to unmask]>
********************************************