<Most amazing report from respected commercial beekeeper in WNY. Kept bees
since 1968, running over  1000 colonies. Has worked as inspector and knows
diseases well.  Last spring put two new Apistan strips in each colony in
March and removed them in June. Surveyed bees in September and found low
varroa counts.  Lost 80  percent with PMS symptoms>
Assuming that report is correct the strips were left in for a period of some
nine to sixteen weeks.  We are advised not to leave them in for more than
six weeks.  Tests have shown that from then on the pesticide level is very
much reduced so we are exposing the mites to a sub-lethal dose, a sure way
to encourage resistance.  All strips should go in straight from the packet,
removed at six weeks and destroyed.   In addition all strips should be out
before the supers go on to avoid carrying the residue into the nectar cells.
The bees were surveyed in September.  I cannot comment for WNY but  here
bees are breeding merrily in September  so a large proportion of mites
present will be in the cells on the larvae and will not show up on a count.
The only way would be to sample the capped brood.  The last few brood cycles
will become the bees that have to live through the winter and feed the
larvae when the queen resumes breeding in the new year.  Researchers report
that one or two mites on a wintering bee will lower its ability to produce
brood food and shorten its life by one third.  Thus we hear many stories of
visibly strong stocks going into the winter and dwindling away to little or
nothing by the spring.  For the time being I think autumn treatment with
Apistan is a must, timed to have the maximum effect to keep the wintering
bees as free as possible.
It is accepted now that the mites can carry a range of viruses detrimental
to the bees.  If they should be carrying a particular vicious strain it is
sheer hard luck on the beekeeper.
_________________________________________________________________
Sid Pullinger                    Email :  [log in to unmask]
36, Grange Rd                Compuserve:  [log in to unmask]
Alresford
Hants SO24 9HF
England