In message <[log in to unmask]>, Stan
Sandler <[log in to unmask]> writes
>Please elaborate James on criteria for EFB comb destruction.
Readers should realise that this is UK experience and legislation and
working (usually) with a single brood chamber. If anyone thinks this
last is strange, I do get 100lb+ from good colonies and 160-200 from
colonies in good apiaries. One of my friends got 800lb from a 5-colony
apiary last year and a half-ton from 8 colonies in a different apiary
this year. These are static and not moved for pollination or forage.

I can only go on the mixed experience of having to call in our Bee
Inspectors over a period of more years than I care to think, since my
first detection of EFB. We are legally obliged to call them in if we
suspect either foul brood. If the colony has more than half its brood
affected the whole hive innards are destroyed, i.e. all frames, honey
included; the hive body and queen excluder are flamed drastically (zinc
excluders melt!). If it is weak it is similarly destroyed. The whole
apiary is examined at the time, a standstill order is put on the apiary,
until it is cleared 6 weeks later. This means nothing goes out. If the
colony is considered strong enough to take medication, outside spring,
then it is given oxytetracycline (I think). In the last case where one
of my colonies was treated in August, we also removed and destroyed 4 of
the oldest combs in the hive and left the 5 most recently given
foundation (this year or last). We wait and see. If a colony is to be
treated in spring, now the preferred method is to destroy all frames and
brood, re-hive the colony on foundation with a queen excluder below
along with medication. I have not seen that in practice since I chose to
destroy all colonies infected in spring this year. In addition, the one
colony treated several years ago had to be destroyed as the disease was
still present 6 weeks later.

Conversations with the various inspectors suggest it is a poorly
understood disease: some consider it endemic and develops according to
stress; others consider it brought in as an infection. There is evidence
about variation in pollen quality notably the extent of linoleic and
linolenic acids keep bees healthy as they do humans. I was given some
information about how a map of EFB incidence has peculiarities,
including seeming to associate with beekeepers who are known to have it
and other oddities that I was asked to keep quiet about. Certainly our
intermittent flows and intermittent nectar gathering cause problems:
confinement means well-fed larvae so they don't starve, but may live to
infect the next generation; abundant nectar may paradoxically mean
minimal feeding so starvation shows up and infected larvae die. Hygienic
bees remove infected larvae quickly so you just may not see it. But you
do see the increasingly uneven brood pattern. Actually if you look very
carefully you may find just one or two infected larvae not yet removed.
I prize colonies that are poorly patterned but have no chalk brood or
EFB for assessment of varroa levels: I hypothesize that they are
removing varroa-infected larvae, which I hope will show up as low varroa
levels.
>-  EFB is not a spore forming bacteria.  I would still like confirmation of
>this,
Yes, this is what I have been taught by all experts.
>  and it leads one to the question of how long the bacteria itself
>remains infective.
I don't know. The thing about EFB is that the infected larva may leave a
small hole in its cocoon, so that when it defecates the faeces are in
contact with the next larva's food. Hence it will infect the next larva.
So, a removed larva will still pass on its infection. I was told that
acetic acid vapour is acceptable to sterilize empty honey supers, but
would not be considered a reliable method for comb used in brood
rearing. In any case, all sorts of bacteria have been found in honey,
presumably inert whilst the honey is capped. So, presumably it would
live on in stored honey until it was used by the bees, when it would
infect the larvae, but at perhaps a sub-critical level.
>  This is a simple question, it should have a simple,
>experimentally verified answer.  It is also a question of importance to the
>idea of comb destruction, and to the beekeeper if he wants to decide how
>long to remove frames from active duty before reintroducing them.
See above. I would destroy all comb used for brood from an apiary that
had EFB confirmed, in case it was in the comb of the hive from which it
came, even if it had been passed as OK. IMHO it is not prudent to reuse
possibly infected comb even if treated with acetic acid. Late spring
bees have wax producing bees in abundance and will draw copious comb.
This year I managed to get all hives in an apiary to redo all the
(single) brood chamber frames by demareeing them (above the queen
excluder initially) in an attempt to remove all possible infection. All
removed combs were rendered after removing honey for personal use as
were honey frames from infected hives (with Inspector's permission).
>3.  The disease certainly does seem to be infective and does spread in the
>apiary so comb removal is likely indicated.
I have one apiary where it reappears year after year even though
colonies are destroyed. The Inspectors suspect a nearby unknown
beekeeper as the source. One trick used by beekeepers (not in George
Imirie's meaning) is to re-colonize an empty hive with a swarm. Once it
dies, they presume it was caused by varroa since they refuse to treat
it, and put in another swarm. So, EFB is preserved and any honey robbed
out of the brood section by another colony will take EFB away. I don't
understand infection of an apiary at all I have to say. Drifting would
normally be the older flying bees that are not feeding larvae. Unless
when they process honey they add EFB bacteria to the honey with the
enzyme. But surely individual bees would add little EFB bacteria. I
suppose strong robbing might do it. Perhaps I should be more careful to
reduce entrances once the main flow stops - too late now!
>4.  Here is PEI the disease is almost always accompanied by severe
>chalkbrood.
This is a mixed blessing. Apparently chalk brood can act as a
preventative to EFB. The chalk brood suppresses the EFB in that cell. (I
only half remember what I was told). In another paper, I read that bees
can also stuff pollen into cells to do the same. This year I saw lots
more colonies than usual stuffing masses of pollen into the brood
rearing area. But chalk brood itself will stress colonies since they
have to keep the area warm but don't profit from the hatching bees to
carry on all the hive jobs: double trouble (especially in spring as the
colonies try to build up).
>5.  Requeening, like antibiotics, is most effective before the disease gets
>going.
Unfortunately this is not an option here: we must report our suspicion,
then apart from consultation, which seems more thorough if you are
commercial, the matter is out of your hands. It might be possible, where
you don't have the legislation, to cull infected combs only, or do this
and then requeen. To do this you'd normally have to be commercial and
have young queens at the ready (or buy them in). I would not be too
happy with the idea of uniting a colony with EFB to a colony without,
though I suppose if you de-queened and put the colony on top of another
one, and removed all comb once the brood was hatched, you might succeed.
But successful larvae in the colony with EFB would simply pass it on to
the larvae they feed. I don't understand requeening as a solution,
unless, as you say, it is at a low level and since bees feed many
larvae, the bacteria are so spread out the number never gets to a
critical level in any bee. In this case, its level would reduce over the
generations. Can anyone help here?
--
James Kilty