Don,
 
        To reduce the likelihood of resistant mite strains evolving it is
advisable to use a highly efficient acaricide (at a known therapeutic level)
over a comparatively short treatment period.
 
It doesn't matter if you're going to take the honey or not, if the strips
(Apistan or Bayvarol) are left in all year 'round there is a risk of actively
selecting for a resistant strain. Few acaricides always kill 100% of the target
every the time but the survivors are NOT necessarily resistant, just lucky they
avoided contact.
However, if the selection pressure is continuous over a long period it IS
possible to promote the emergence of a more tolerant or resistant strain.
 
Label directions on professionally manufactured treatments are there for a
reason; the application and efficacy etc have been thoroughly tested by
independent beekeepers and bee scientists long before the instructions for use
are printed.
 
For more information on resistance see the February issue of Bee World, produced
by IBRA.
 
 
 
Max
 
______________________________ Reply Separator _________________________________
Subject: Varroa treatment
Author:  [log in to unmask] at INTERNET1
Date:    1/28/97 6:42 AM
 
 
There has been much discussion, research, scientific studies and
wishing, since the dreaded varroa has attacked and done so much damage.
Several discussions have mentioned the mites building up resistance to
the medication, some saying it is because of improper use. Is it worse
to use too little for to short a time or to leave the strips on too
long? If a few mites are still in the hive when the strips are removed,
it seems to me that they might be the ones building up the resistance. I
know someone(he is smarter than I am, so telling him is out) that only
uses his bees for polination and therefore leaves his strips on all the
time. If all the mites are dead and there are none in the hive to become
resistant, why not leave them there?
 
Comments appreciated.
 
I personally follow the instructions and treat twice yearly.
 
Don
 
PS I went out to treat my hives last week and couldn't find the bees. I
believe they were playing "hive and seek" with me.