Given a 97% hypothetical kill by using weak strips, the 3% of mites that
are left might be tolerant to *that weak level* of miticide.
 
You can't get 'em all.  Even if you have the supposed 99% kill, that leaves
1% surviving.  Why not take that result to the same conclusion -- it means
that remaining 1% will still reproduce, and their offspring may well end up
"tolerant" to the original concentration in the new strips.
 
Given time, even that 1% would foil the use of Apistan as a reliable control.
 
On the other hand, a higher-than-recommended dose of fluvalinate would
leave only the truly tolerant mites remaining, and then eventually their
offspring could really make attempts at further control a nightmare.
 
Bear in mind that the talk was given by a Sandoz representative... ;-{|
 
What say ye?
 
----------
Lloyd Spear wrote:
 
>I am not disputing what you said as a matter of pride, but only as what I
>hope will be taken as clearing up a misconception.  My comments come from
>listening to both representatives of Sandoz as well as representatives of
>Ohio State, Penn State, and Cornell.
>It is, as stated, very important to leave the strips in only as long as
>directed on the package.  The reason is that the chemical discharge from the
>strips weakens over time and it is very important to keep a chemical
>discharge with the planned potency to kill 99% of the mites.  If fewer than
>that number are killed, those remaining will be exposed to a dosage that is
>less potent and will build tolerance to the chemical.
>Replacing the strips with new strips (with the 99% killing power) will not
>encourage build up of tolerance!  Leaving in old strips with a reduced
>killing power will!
>In fact, one of the most interesting talks I heard (from a Sandoz
>representative) was what would be the hypothetical result of a 97% kill
>rate, rather than 99%.  It was frightening to hear him go through the
>numbers on mite reproduction, with the 3% left, and what would happen to the
>hive!
>Hope this helps.