hi all!
 
 
A few more remarks on the resistancy of Varroa mites to fluvalinate ( Apistan)
and flumethril (Bayvarol), seem in order:
 
1. as has been established on several occasions( cf. a.o.
my previous message on this theme), colonies in northern Italy
have in fact shown a reduced sensitivity to Apistan strips,
while this seems also to be the case for Bayvarol strips.
This has obviously to do with the resemblance in molecular
structure of both active ingredients. They both belong to
the same group of Pyrethroids. It follows, that in order
to prevent inducing resistance in V. Mites to either acaricide,
it is better policy to implement a mite control scheme based on
one of these pyrethroids alternating with a totally different
chemical treatment, such as formic- or lactic acid. Alternating
two chemicals from the same group would merely enhance general
resistance to the group as a whole.
 
2. If I remember correctly from my days in molecular genetics,
resistancy resides in small circular pieces of DNA, called
'resistancy factors' . These minute pieces of genetic information contain the
genes involved in resistancy against e.g. a certain chemical, and they can be
passed on from one individual to rthe next and so spread much like virus
particles. This is one asdon why we have a shared responsability not to bring
these resistancy factors
into existence, after which they'd 'infect' every other beecolony on earth.
This 'epidemy' of resistance would obviously make it very hard to control mites
any more thereafter..
 
sincerely, Hugo
 
 --
 
                               Hugo Veerkamp
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