Hello Rob & All,
Rob wrote:
I meet the state bee inspector today who told me of an experience last week
 in a corner of our state. Apparently a hive being treated with Apistan
 (after several weeks) was still infested with varroa. Perhaps resistant
 mites are inevitable. I also thought maybe they were old strips (known or
 unknown to the beekeeper). I know there are other treatments for the mites,
 but wonder if anyone has first had experience with resistant varroa.
Bob wrote:
I saw my first fluvalinate resistant mites four years ago.  I expect to see
Coumaphos resistant mites this year.  I expect the same trouble convincing
beekeepers of the Coumaphos resistant mites as I have had the last four
years convincing beekeepers of fluvalinate resistant mites.  Varroa is going
to get harder to control.  Many *bee-havers* are going to quit beekeeping or
be content with buying packages each spring.   I notice you left the name of
your state inspector and your state out of the post.  Both of you need to
search the Bee-L archives for information on resistant mites.  Use resistant
mites and my name in the search.  Now is my busy time so I haven't got time
to go over such a complicated subject ( which is in archives) but will try
to address new concerns.
Sincerely,
Bob Harrison
Odessa, Missouri