>> And how would you tell when the comb is back in the hive whether the
AFB scales you are seeing are new or old?
>
> I doubt you could tell with this treatment or any that leaves the comb
intact like the just mentioned ethylene oxide method.

Very good point.

There are some management schemes where this presents much less of a
problem, such as those where medication is used routinely to forestall
outbreaks, but nonetheless, finding scale under such circumstances can
present a quandary.  Active AFB may, indeed be a threat in the case of a
botched treatment -- or a renfection.  Since visible scale will no
longer be considered a definitive indicator of the presence of active
AFB after such treatment, added vigilence -- and some logic -- becomes
necessary in the search for and identify active disease in the first
year after treatment.

After a year, most scale will be removed by bees, if it is properly
managed, and located where the bees will work on it in a reasonably
strong hive of healthy bees.  After that, new sightings of scale will
again become more meaningful.  Also, scale changes appearance over a
period of time in a hive, and, with some practice, old scale should be
identifiable.

Immediately after the treatment, though, the situation can be confusing
if the beekeeper does not know what is in his hives and also has not
marked the frames that have been treated by fumigation or radiation
before inserting them into random hives, and particularly where the
beekeeper considers any bit of scale -- in total absence of any active
disease -- a cause for panic or a bonfire, rather than something to
ponder.

Suffice it to say that after treatment with either ETO or radiation, the
criteria for declaring an AFB outbreak will be different.  Simply seeing
verifyable AFB scale will not be enough.  Active disease and/or a high
active spore count become the indicators of reinfection.  Fortunately --
from reports I've heard, radiation -- done properly -- is as close to
100% effective as possible.  I personally -- decades back -- found ETO
to be much less reliable, possibly due to my own management at the time.

As a footnote: Kim mentioned to me some time back that in the case of
particle radiation (as opposed to electron beam radiation (what exactly
is the difference, Jim? -- I though all radiation could be treated as
either)) -- brood boxes deteriorate after several trips through the
device.  After several trips, the wood gets soft and the nails fall out.
I've asked the guys who use electon beam and they say they don't see any
ill effects.

As always, we have a problem when discussing these sorts of topics here
on BEE-L, in that we are a very diverse group, with idealists tyros, and
dilettantes side by side with large scale practical beekeepers,
extension people and researchers -- plus others with long-term
experience located all around the world.  People who see and deal with
AFB on a daily basis are conversing with people who have to try hard to
imagine what the disease even looks like.  As a result, we are wide open
for all kinds of misunderstanding due to extremely varied expectations,
experience, standards, practices, climates, jurisdictions, and  locales.
No one answer is going to satisfy everyone.  It is interesting to see
the different perspectives.  I know mine has changed a bit with time,
and with exposure to ideas from around the world.

allen