>
> >I sent samples to the NBDC in Alberta from all of my yards a couple of
> times and could find no correlation between spore count and productivity or
> spore count and overwintering success.


I tracked 36 colonies in the Sierra Foothills over the course of a year
(few periods during winter over 10 days without flight), taking monthly
spore counts(25-bee average) and prevalence of infection (infected bees out
of 10).  I too did not find either count to be a predictor of either future
colony performance or overwintering success (seldom did any of the colonies
exhibit more than half the bees infected).

That said, there is plenty evidence that nosema causes morbidity and
precocious foraging.  I have been unable to come to any conclusion as to
how bad a problem N ceranae is of itself.  But coupled with an in-hive
epidemic of a virus, I've seen it lead to rapid colony depopulation.

And when I compare my most productive colonies in summer to the least
productive, the latter group tends to have more nosema.
-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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