> Here in the UK we have a problem with Varroa control. The only chemical
> treatment which is approved for sale is Bayvarol which is expensive. I
> would like to alternate Bayvarol and Apistan to reduce the chance of buili=
ng
> up resistance.
 
 
Mick,
 
At first hand this seems to be a good idea. However, at the Apimondia
conference in Lausanne it was reported that honeybees in Italy became
resistant to both Apistan and Bayvarol. It seems that for cost reasons
Italien beekeepers substituted Apistan with an other chemical containing a
synthetic pyrethroid, sometimes even spraying this stuff directly onto the
bees! This huge overdoses resulted in the Varroa quickly becoming
resistant. This cross resistance is rather surprising but a fact. The
moral: Please use only Apistan or Bayvarol and then only in accordance with
the label instructions.
 
=46or the moment you seem to be save. Italy seems to be the only place where
this resistance occurs. But given the fact of the intensive international
trade with queens it's only a matter of time until the Varroas in England
will be resistant too.
 
In case you are interested the following paper gives you more details:
 
- N.Milani: The resistance of Varroa jacobsoni to pyrethroids: A laboratory
assay
Apidology 26 (1995), pages 415-429
 
e-mail me in case you can not get a hold of this journal. I will send you a
copy.
 
God luck and few Varroas
 
Hans
 
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=00=D9=00=00=00=00____________________________________________
________
Hans-Ulrich THOMAS. Beekeeper & collector of books about:
 
- bees and beekeeping
- ants (yes these small little buggers!)
- nature printing
 
e-mail:  [log in to unmask]
CompuServe:  100045,2556
=46ax:  +41 1 633 10 77
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