I know of two nuc colonies in a high-varroa area that have thriving
colonies and two-year old strips in them (these are not honey-producing
colonies).   "Don't reuse Apistan" appears to be a frequent note on this
list, but What are the REAL facts on the effectiveness of reused Apistan?
 
    I've read the widely published article showing significantly lower
fluvalinate in the strips within a few weeks (but never Zoecon's own
research). However, Dr. Frank Eischen of the Texas Agricultural Experiment
Station at Weslaco, Texas wrote in the December 1995 issue of American Bee
Journal:
 
  "There are published reports from Europe showing 99% effectiveness of
Apistan strips used five times over a period of five years (Pechhacker,
1993).  I have also received personal communication from knowledgeable folks
outside the U.S. attesting to good efficacy with multiple use.  This issue
needs to be resolved as soon as possible."
 
  The study he cites is Pechhacker, H. 1993.  A successful strategy for
Varroa control.  In: pp. 551-555. Asian Apiculture.  L. Conner et al. eds.
Wicwas Press.
 
 
I have also read speculation that reuse of Apistan may accelarate resistance
of the mites to the pesticide.  Is this REALLY true?  In the December 1995
issue of American Bee Journal, David M. Noetzel, Extension Entomologist
Emeritus from University of Minnesota, suggests almost the opposite.
Responding to the earlier article from James Bach, he writes (page 791):
 
  "...you cannot have miticide resistence without intense (i.e. high kill)
selection.  Unless Mr. Bach has objective evidence that mite resistence to
fluvalinate (Mavrik) is a multiple gene resistence, he has no basis upon
which to suggest that a low dosage of fluvalinate speeds the development of
resistence.  ...
   To date where resistence has been traced to the gene level, it has been
determined a single gene confers resistence.  Hence high dosages always
speeds resistence development."
 
  In essence, Mr. Noetzel appears to be saying that the high kill rate of
Apistan during the first 45 days does more to speed the development of
resistence than a lower kill rate that might occur with weaker fluvalinate
treatments.
 
  I'm not a professional scientist, nor do I advocate any illegal use of
chemicals, but Mr. Noetzel's report, the reports of  high effectiveness
resused Apistan (Pechhacker, 1993 Asian Apiculture, p 551-555, Wicwas Press;
and Dr. Frank Eischen, ABJ, December 1995 pp 815-816), and my own knowledge
of nucs surviving in high-varroa environments indicate that the issue is
quite unclear.  IMHO, what we need now is more factual evidence to either
replicate or refute the various claims.
 
  Can anyone give us recent scientific evidence on Apistan reuse?
 
Regards,
John in Dallas, Texas