> I have never been able to see it as a problem in my outfit, and I've
looked.In my case, I could not even find one spore in my own samples and
had to borrow bees from a friend to prove I was using the right techniques.

Since you could not find a single spore, I certainly would not expect it to
be a problem : )

Calif beekeepers also tended not to see N apis as a problem, and I had
trouble seeing N ceranae as a problem.  But the closer I look, and the
results of trials by myself, and of others (e.g., Pernal in Canada, and
Eischen in U.S.) strongly suggest that N ceranae can be a real problem.

I'm still not using fumagillin as a matter of course.

In answer to Geoff, fumagillin is rather expensive, and as Allen said,
commercial beekeepers are loathe to spend that kind of money year after
year unless they see results.

The amount of adverse affect due to nosema infection is complicated by a
number of factors, including nutrition, varroa, viruses, the fecundity of
the queen, genetics of the bees, chilling, ability to take cleansing
flights, beekeeper manipulations, spore reservoir in the combs, etc.  So it
makes simple answers more difficult.

Even the testing for econonomic treatment thresholds is difficult, due the
the influence of a single infected bee in a sample.  That's why I'm also
studying the prevalence of infected individual bees in the hives.  I have
an article on that coming out in the next ABJ.

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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