Hello Medhat!
Just "another" George.

After reading your comments about using Apistan in the fall and formic acid
in the
spring, I had to agree with you.

As you "may know" from my writings, particularly in the PINK PAGES, I have
STRONGLY advocated the use of Apistan LATE in the fall and always for 6 weeks
but
NEVER to exceed 8 weeks.  Here in central Maryland, we always have 5-6 days in
December where the temperature exceeds 50°, so we can remove Apistan because
the bees are not clustered.  I have installed my Apistan on October 1st on my
50-100 colonies and removed it the first 50° plus day after November 15th.
Since
few queen bees are laying any eggs after about November 1st, the mites have
no bee larvae to lay their eggs, so perhaps I am getting 99.9% Varroa kill.
The proof is my sticky board tests on April 1st, which are 0-1 mite, or my
July 1st sticky board test which rarely exceed 20 mites.

The problem seems to be that most beekeepers are not willing to take off from
work to remove Apistan of a warm weekday; and hence start using Apistan
EARLY, like September 1st, and maybe do not leave it in place for a full 6
weeks.  I have been unable to persuade many beekeepers to hold off until
October, and then they use Apistan 2-3 times per year.  They say "George, you
are retired and can tend to your bees on weekdays"; but I note they going to
fall baseball games, hunting, fishing, etc. on weekdays and seem to mentally
justify those work vacation days, but not to take care of their bees.  It
discourages me.

If you are coming to ABF in Savannah next week, look me up.  I have to
conduct a workshop there, but it will be good to hear all about your new job
at Rutgers.

George Imirie
Certified EAS Master Beekeeper
Starting my 70th year of beekeeping in Maryland
Author of George's PINK PAGES