>
> >IPM.  It works with other pests, Why not AFB?


Good question, Allen.

I don't have any strong opinions, but I have a heckuva lot of experience
with AFB, and have had to burn large numbers of colonies at times to get it
under control (this was before Tylosin was legal).

In answer to your question, there is one trait of AFB that separates it from
all other pathogens--the extreme longevity of the infective spores, which
are fairly readily spread by drifting, robbing, and frame transfer.  This
means that a reservoir of inapparent infection can spread and build without
the beekeeper's knowledge, ready to explode at the first nutritional stress
event.

The keeping of AFB-resistant stock is of course the best strategy.  The
easiest type of  resistance to test, uncapping and removal behaviors, can be
tested with the freeze-killed brood (FKB) test (note that this is only one
of several resistance mechanisms).  I sold such queens in the early '80s,
and watched their colonies completely clear up intense AFB infections
easily.

However, with current breeding selection for mite and nosema resistance, it
may be tough to always maintain FKB hygiene.

Whether tolerance of AFB spores in your operation is acceptable also depends
upon whether you sell bees or combs to others.  I once bought back a load of
nucs from a buyer, plus paid for his newly-contaminated combs, when I
inadvertently sold him a load of nucs that had robbed out an AFB deadout,
and came down with AFB after the sale.  After that, I have been stringent
about keeping my operation clean, which requires the burning of contaminated
combs.

A couple of years ago I tried an experiment, and set up a test yard of
colonies that only showed one to a few infected larvae, to see if they would
clean up the disease spontaneously (bees not selected for FKB hygiene, and
no antibiotics given).  They didn't--the disease increased.  Ditto with
infected comb removal.

I used to prophylactically treat with OTC patties (also have used dusting,
syrup, wax paper rolls, etc).  What I found in my own California operation,
was that it was more cost effective (what with the cost of Crisco, sugar,
OTC, and labor) to simply burn infected combs, and save the adult bees by
"shake and bake" with a shot of Tylosin to the shook swarm.

I currently avoid any prophylactic treatment, since I want to flush out any
infected colonies, so that I don't spread the spores, nor sell contaminated
nucs.

After looking at the data from New Zealand and England, where burning is
practiced, I'm very impressed by how AFB can be relegated to the status of a
rare disease.

I am very much aware how many commercial operations in the US now routinely
feed Tylosin (which has a half life measured in months) in syrup each fall.
This practice, although illegal, certainly keeps AFB under control, at least
for the time being.  However, right or wrong, many consumers ask for honey
which has not even the faintest taint of antibiotics.

I'm curious on Bob's take on this.  Do your large outfits simply treat, or
do they burn?

Unfortunately, in my area irradiation facilities are not readily available.
Many Aussie beekeepers routinely irradiate used equipment, and as Allen
notes, the sterilization of myriad pathogens in old combs results in renewed
brood health.  For beekeepers who have access to irradiation facilities,
this would likely be more cost effective than burning.  You'd have to do the
math--10 new presassembled frames with foundation cost me about $16.00, and
I don't have to truck hives back and forth to a facility.  For a colony or
two, it's cheaper for me to burn.

When I am in almond pollination, with thousands of other colonies within
flight distance, and often yards stacked with deadouts, I am understandably
curious about the AFB content of all those deadouts being robbed out!  So
the AFB strategy of other beekeepers directly affects me.  I'd feel a lot
more comfortable if I knew that they had AFB under control!

So, IPM for AFB is an individual decision (where legal), but your decision
can affect adjacent beekeepers.  If you are isolated and don't move your
bees, experiment at will.  If your operation has the potential of infecting
others, then I feel that you should take that responsibility into
consideration.

Randy Oliver

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