>FWIW, I am somewhat skeptical that comb fumigation with acetic acid, and
>comb renewal programs are sufficient to solve the problem (although I do not
>disbelieve the European experience).  I started over 200 packages this past
>spring from New Zealand, and they were shaken from two different beekeepers.
>I also picked up another batch of over 200 for other beekeepers.  In both
>cases the majority of the load came in excellent condition and some were
>very very poor.  It was determined that one of the beekeepers had high
>levels of nosema and this was the likely cause.

Although it is some years now since we imported package bees due to
health restrictions, there was always a golden rule.

NEVER, NEVER instal them without a good feed of clean fumidil treated
syrup. The same applies in almost as great importance to shaken swarms,
which we HAVE done in more recent years (basically a package you make
yourself).

Without treatment bees subjected to this kind of stress suffer a high
attrition rate from Nosema, and related dysentry. Untreated, as many as
75% could die in the coming winter, yet that can drop to below 20%, even
below 10% with the use of fumidil.

5 years ago I was tempted to do an experiment with shaken swarms (in
May) and found that of the 20 left untreated only 3 survived (and all 3
were weak) the coming winter, even after the whole summer to recover
from what had been done to them, but 16 of the treated ones came
through, of which many were strong. I reckon that is an experiment not
worth repeating.

It does take bees a good while...up to a year, and sometimes more... to
fully get over having this done to them. They have been stressed
severely and that does make them vulnerable to the nosema which is
around everywhere.
Even migratory operations sometimes are plagued with high numbers of
small colonies and slow build up in spring which is often related to
some degree of nosema, again stress related.

Yes, we fumigate all the combs from winter dead outs.
Yes, we cut out and burn any heavily soiled combs from apparently nosema
troubled colonies.
No, we do not routinely treat with fumidil, except where stress has been
likely.
However, all these have their place in a balanced programme of
management for nosema.

Local factors have a great influence as well. We have cold, but not
severely so, winters here in Scotland, which tend to be long, grey, and
damp. Typical of maritime climates, but by tradition this is just the
kind of winter to give rise to nosema troubles.

Others on the list will have completely different problems which means
that there will be no substitute for local knowledge of what works and
what does not for your area.

I guess that what this really comes round to is that I probably agree
with Stan. Given management practices involving high amounts of
migration, coupled with the use of packages or shaken swarms and
temperate to cold weather wintering, that fumidil is an important weapon
in the battle to contol nosema. I do not subscribe to the view that it
should be a universal, annual treatment, certainly in our local
circumstances.

Murray


--
Murray McGregor