Hi Guys,

In Bob's recent posting it was proposed that thymol treatments were only
effective if combined with an Apistan treatment during the same year. It's
not that simple; in many European and other countries there is widespread
resistance to pyrethroids, coumaphos and to amitraz. Many, many beekeepers
are using thymol-based treatments WITHOUT the backup of an Apistan, Perizin
or Apivar type treatments because they just don't work in some areas. So I
can't agree with Bob's premise.

In my own opinion, thymol/organic acid treatments of any type on their own
may not provide the 97 - 98%+ control of mites every time such as we have
seen with Apistan and some other treatments but sometimes they do. OK, the
results between colonies may be more variable than with Apistan treatments
but at least there is no resistance and mites are being eliminated from the
hive. A further treatment of some sort may be necessary but isn't it worth
it to overcome this plague of resistant mites?

As far as I am aware, there is no wonder drug around the corner to replace
Apistan [or Checkmite in The States]. Varroa resistance is serious trouble
and will only be restrained (not eliminated) by IPM practices being
introduced in treating our colonies.

Monitoring is crucial to the success of IPM and good hive management.

Chris Slade earlier referred to resistance reversion in varroa; from the
European monitoring trials we have been involved in, pyrethroid resistance
as a character may start to be reduced from a varroa population over the
course of 4 years. It depends on many factors, not least the abstinence of
any form of pyrethroid treatment within the region over a 3-4 year period,
or longer.

In the USA, where beekeepers are now seeing resistance to pyrethroids, to
coumaphos and to amitraz, this is not going to disappear overnight; it will
gradually grow and spread unless other methods are used.

Thymol-based treatments such as Apiguard, organic acid treatments or
biomechanical methods may not be everyone's preference but they may be more
helpful than you think, whether the mites in your colonies are
pesticide-resistant or not.

I guess it's a matter of individual choice.


Max

Dr Max Watkins
Vita (Europe) Limited
21/23 Wote Street
Basingstoke
Hampshire RG21 7NE
UK

Tel.: +44 (0) 1256 473177
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