I agree that the most practical way to determine whether a varroa treatment
is necessary or not is to monitor the colony closely, checking mite fall; it
makes no commercial or practical sense to treat a hive if there are no or
very few mites in it. Whether or not a colony's varroa are
pyrethroid-resistant (or OP or other chemical resistant) or not may be
useful to know if you want to avoid wasting more money in future using a
treatment in that hive that gives insufficient control.

The pyrethroid resistance field and laboratory kits (developed in the early
90's by Europe by Vita (Europe) Limited and the University of Udine, Italy
by the way with a modified version being used later in The States by
Beltsville) are tools only. They can be used to give a more accurate
diagnosis of resistance before a beekeeper wastes money and time on a full
treatment. In Europe we (Vita and various beekeeping institutes) use them
for monitoring resistance and the potential for reversion in area of known
resistance, not as a commercial product.

Resistance can be incorrectly diagnosed - as an example there was one
beekeeper a few years back who claimed resistance to Bayvarol (another
pyrethroid treatment) as he had put the strips in his colony and very few
mites fell. On close examination the hive was found to contain no mites - ie
a very low infestation, not resistance! Mites in the hive following a
treatment isn't always an indication of resistance; reinvasion is very
common especially in highly infested colony locations, treatments aren't
always used properly etc. The resistance kits will be able to confirm the
presence or absence of resistant mites, for sure but they must be regarded
as one tool only. Monitoring the colony is simpler for many professional
beekeepers and as Allen says, if the resistance levels are high and you're
monitoring frequently, you'll soon know about it.

Power to the sticky board!

Max

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

Tel.: +44 (0) 1256 473177
Fax: +44 (0) 1256 473179

e-mail: [log in to unmask]

web: http://www.vita-europe.com

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