An integrated approach to mite control is exactly what is needed, using
biomechanical methods as well as organic acids/essential oils and other
effective products, where legal and practicable.

However, alternating Apistan with a coumaphos-based product may be OK as a
short-term measure, where varroa pyrethroid resistance levels are not high
(requires total abstention from using pyrethroid hive treatments in the area
for at least 2 years) but maybe not for the long-term.

In Italy and Spain, where both tau-fluvalinate and coumaphos have been used
for quite some time, resistance to both classes of compound has arisen.
Moreover it seems that there could be a cross-resistance between the two
classes in the varroa mite; once they are resistant to pyrethroids, they may
have some resistance confirmed to organophosphates and vice versa. Evidence
to this effect is building but not concrete as yet.

This may be different in North America as I understand the mechanism(s) of
pyrethroid resistance in varroa there are different to the known European
resistance mechanisms.

The answer must be to use several different approaches to varroa or other
bee disease control, within and/or between seasons wherever possible, to
minimise the risk of resistance emergence and to prolong the lifespan of all
treatments available.


Max

Dr Max Watkins
Vita (Europe) Limited
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