On  9 Dec 97 at 22:48, Vince Coppola wrote:
 
>  I agree with David on this one. Andy's statement is poor advice for
> anyone wintering bees in the north. There is plenty of data on the
> affect of T-mite and not to treat is foolish. Before treating our
> losses were as high as 55%, treating got us below 25% and breading
> for resistance has almost eliminated losses to T-mites.
 
It is very possible that Andy's advice forgets the necessary
temperature controls of the winter cluster. Dr. Nasr has done a great
deal of work on "Thermal Regulation"and this explains why Northern
bees die with T-mite infestations, whereas Southern bees do not.
        It seems the cluster regulates the internal temp by increased oxygen
uptake. Obviously if the bees trachae are blocked with mites they
cannot absorb enough oxygen to keep the cluster warm under our low
temp conditions. This accounts for excessive winter kill due to
T-mites in the North.
        We have been in the Ontario Breeding for 4 years, and when we first
started to test and select for T-mite resistance we were finding up
to 250 mites per bee. Now by selection and breeding we have reduced
that to no mites or figures like .25 mites in 50% of bees tested.
Well below the economic threshhold. In other words, at these figures
there is no need for treatment or loss to T-mites.
        Worthy of comment?
 
 
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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
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