Good questions Matthew,

Let's first step back a bit, and to biology and immune responses in
general.  What researchers are finding is that the adaptive and innate
immune systems evolved in a "dirty" world in which organisms were
continually exposed to parasites (including bacteria, fungi, and viruses).
Some of the adaptive immunity can be passed from parent to offspring, by
various mechanisms. Organisms reared in sterile environments may not fare
as well under natural conditions as those that grew up in the dirty world.

Bees may be similar--the queen can pass immunity to bacteria via binding of
bacterial proteins to vitellogenin, the nurse bees can pass dsRNA and
possibly other factors to the larvae, etc.  So perhaps we should be asking
the question, Do we really want to baby our bees and try to protect them
from exposure to every possible comb-transmitted parasite?  As a breeder, I
choose not to.  I want to breed for bees that handle such "normal" exposure
on their own.

That said, over the years I've followed studies on comb sterilization.  It
can clearly be of benefit against AFB, and some studies indicated benefit
against *N. ceranae.*  But not all studies have shown benefit from
irradiation.  Ozone is expensive and difficult to get to a high enough
level.  The hobby beekeeper could simply spray a solution of bleach on the
combs, or perhaps briefly expose them to the UV radiation from the sun
(each side, directed into the cells).

The practical question to me is whether the hassle and expense are worth
it?  That's why I shared my practical experience.  I'm not saying that
there may not be a benefit, but in my operation, we simply see little
impact of disease so long as we keep varroa under control and provide good
nutrition.  When we occasionally observe the apparently new form of EFB
that doesn't go away on its own, we do treat those hives with oxytet, but
that's only a handful of hives most seasons out of the 1600 that we've been
running.

>You note that you remove sick hives to their own yards- why would one do
> that if it weren't trying to prevent the spread of a disease? Or are there
> other reasons?
>

We've only done that a couple of times--last time a few years ago when EFB
and IBDS was ravaging hives.  I moved the sick hives to a single yard to
see which ones would cure themselves, then  once the bees and brood looked
healthy, moved all the equipment back into the operation .

I can't speak for beekeeping in other areas or under other conditions, and
I don't like to give advice.  I myself don't feel like playing Florence
Nightengale, but would rather just be a breeder of tough bees.  So it's
really a personal decision for you to make.  Again, over the years, under
my conditions (with really tough late summers for bees), so long as I
manage varroa and provide good nutrition, I observe few health problems.

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

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