Dear All,

I copied the recent posts on the UK Varroa resistance issue to Medwin
Bew, head of the National Bee Unit (who does not currently subscribe to
Bee-L) and am forwarding his response below.

For those that want more information about the discovery of resistance
in the UK and its geographical distribution, the Pyrethroid Resistance
pages on our website (http://www.csl.gov.uk/prodserv/cons/bee/) may be
of interest.

James

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Thanks to everyone for their helpful comments on the development of
pyrethroid resistant varroa here in the UK. It is useful getting the
views and experience of others overseas who are dealing with the same
problem.

We didn't claim that varroa resistance is only caused by misuse. As a
research lab with many years experience in pesticide research,
application and impact, including mite control, we are aware that
resistance develops naturally with any product in time. We have also
been working closely with European colleagues dealing with resistance,
including the European Apistan distributor, for many years. The
epicentre of the UK case of resistance found so far is DEFINITELY linked
to confirmed and persistent misuse. Misuse accelerates resistance onset
considerably.

We are trying to get across to people that (a) they should check for
resistance routinely, (b) they should follow the treatment label so that
we can keep products as long as possible on the market shelf before
resistance sets in (i.e., don't misuse them) and (c) they should
alternate products they use. We have adopted this approach for years.

The problem is that we only have Bayvarol and Apistan as authorised
products so far, although others are in the pipeline but could take a
while for approval. In the meanwhile we are seeking Special Treatment
Authorisation for alternative high efficacy products that we can use to
treat the colonies in the immediate area this autumn. This will at least
slow down the spread of resistance. We are well aware that it will not
stop resistance in its tracks and well aware that there could be other
epicentres we are not yet aware of. That's why we put a national
screening programme in place a while ago and why we are instructing
beekeepers how to check for themselves. We have done this for years in
preparation for the inevitable. We do know that there is a possibility
that resistance we are dealing with could well cover a wider area.

Not everyone in the UK uses pyrethroid. Many use organic acids,
essential oils and the like. So spread of resistance to pyrethroid on a
wider scale will be a little slower. We are not hiding our heads in the
sand, by the way, and never have done. That is why the screening
programme was put in place, why we have had an advisory campaign on the
subject for years and why our screening targets misuse first AND random
checks second.

Medwin Bew
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James Morton
South-Eastern Regional Bee Inspector
Central Science Laboratory
National Bee Unit
Tel/fax: 020 8571 6450
Mobile:  07719 924 418
E-mail: [log in to unmask]
CSL website: http://www.csl.gov.uk
National Bee Unit website: http://www.csl.gov.uk/prodserv/cons/bee/
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