> Al said: "There was some thoughts that it will take N generations of
> mites
> before Apistan will be useful against a mite population that
> had become resistant. Rotation would only continue the resistance."
>
> The thought is, isn't it, that those bees resistant to Apistan are
> all killed by the Coumaphos so they disappear from the gene pool
> altogether?  Dan
>

No, nothing kills all the mites. 99% is the best I have seen claimed.
Apistan kills 99% of the mites until most of the mites left were resistant.
Then the Cumaphos kills 98% of the mites, Apistan resitant and non-Apistan
resistant in about equal proportions until the population is mainly Cumaphos
resistant. This new population would still be partialy Apistan resistant.