Half Moon Disorder,
or Half Moon Syndrome
Do you really have EFB? (don't burn that hive just yet).
A chap that I correspond with on various Email
lists known as "Pav" Asks... Do you really have EFB?
Most of this page is due to his effort, with contributions from others...
I have merely assembled it in the editorial sense, I did allow him
editorial oversight after he expressed discomfort with his initial
raw email living the life of a web page... Thanks Pav.
Do you folk have, or have you heard of 'Half Moon Syndrome'?
Briefly, Half-Moon Disorder is a common non-infectious
genetic/nutritional (pollen?) problem, the symptoms of which mimic
EXACTLY those of EFB.
A few years back a Nelson (NZ) beekeeper saw EFB signs in a
hive (we don't have EFB in NZ), prompting a full scale Outbreak
response from the authorities.
Other hives were found with it, and samples were sent for
tests in Australia (where they DO have it).
All the experts involved had no doubt they were seeing EFB
- the visual signs were identical.
And so we learned about Half Moon Syndrome. Now I've never
seen it, except to be shown photos of EFB and told that this is
exactly what Half-Moon looks like. And I don't recall (to my chagrin
right now) that they have actually figured out exactly what the cause
is, although I think nutrition and genetics were predisposing factors
[doing some homework since writing the email here,
I can confirm that it is a nutrition problem with genetic
predisposition - there is no infectious agent involved]. The bit I do
recall (my inadequate cerebrum saves space by just holding on to the
relevant bit) is that requeening (and supplementary feeding) fixes the
problem. Sound familiar?
Some Australian beekeepers started calling for immediate access for
their honey to NZ market (currently not allowed, as we try NOT to get
EFB). Yet the lab tests came back negative - NOT EFB. The experts
were bamboozled, the Australians insisted the lab was wrong, that
they recognised EFB when they saw it.
Since then I often wonder when I hear foreign beekeepers
talking about EFB, and how usually its not too bad, requeening will
sort it out etc... Are they really dealing with EFB, or do they also
get Half Moon Syndrome, and mistake it for the more familiar EFB as
our experts did?
Who's heard of it? Where does it exist? Who can
differentiate it from EFB without Lab testing?
Subsequently Pav did some homework and later said..."
I believe I know the answers to my questions:
-none of you have heard of it
-HMS is mistaken for EFB very (very) often.
[Positive differential diagnosis from EFB is only via lab tests. More
practically though, try requeening and supplementary feeding BEFORE
The New Zealand National Beekeepers Association web-site had
some information about Half-Moon Disorder:
This same page has online pictures of EFB (and others) from NZ disease
Thumb 1 :
EFB-infected larvae showing yellow discolouration and prominent
Thumb 2 : EFB-infected larva showing typical twisted (corkscrew)
Clicking these thumbnails will link to the article at the above
address with the full-sized pictures.
I found this:
"... Half Moon Disorder (HMD) ...
HMD occurs everywhere. How do we know? Because it has been isolated
(By Dr. Dennis Anderson - Australia) to a lack of adequate nutrition
of the young queen prior to mating. This nutrition is directly related
to the number of correct aged nurse bees in the mating nuc/hive. This
causes faulty development of the queen's ovaries leading to larvae
that are rejected by the feeding nurse bees whereupon they *die of
Why was HMD discovered in NZ at such a late date? Because we
don't have EFB here. Larvae with EFB *starve* due to competition from
bacteria in their gut. In HMD and EFB, the young larvae die at the
same age from starvation.
This results in *Identical* visual symptoms. Around the
World it is almost certain that HMD is routinely diagnosed as EFB and
hence no further explanation is ever sought. Only in New Zealand with
its absence of EFB did the HMD mystery attract enough attention to
enable it to be explained."
A seemingly less informed article at:-
had this to say:
"A number of commenters were concerned about a disorder called
half moon syndrome (HMS) that has been reported in New Zealand
honeybee colonies. Commenters said there are reports that HMS may have
been [[Page 5998]] introduced into Canada from shipments of New
According to our information, HMS is not known to be present
in any country other than New Zealand. In 1984, ARS researchers
visited New Zealand to study honeybees and honeybee diseases there,
and specifically to study HMS. Field tests conducted in New Zealand
by ARS researchers to determine the communicability of HMS indicated
that the symptoms of the syndrome could not be reproduced in a
healthy colony, even when the healthy colony was given a massive
inoculum (a comb containing larvae with HMS). In laboratory tests, no
pathogen or other causative agent of HMS could be found. Field
observations of New Zealand colonies also showed that symptoms of HMS
appeared to clear up in time without assistance or treatment."
Pav was writing in response to a mail
Ken Hoare wrote: (to an Email List).
EFB is the big problem both locally and nationally. I believe I
noted the figures correctly but in 2000 there were 1060 incidences
compared with 850 in the previous year. In my own area EFB has
increased two and half times over the previous years figure.
I am not being unkind to anyone, but I guarantee if I had a hundred
beekeepers with me at this very moment and showed them a comb infested
with EFB there would only be a VERY SMALL proportion that would be
able to identify the disease. Let's be honest even the 'experts' find
it difficult and send combs away for microscopic examination. Be
honest, how good would you be?
But I believe help is already close to hand.
Do you remember the coloured brochures our Ministry distributed, there
are several of them, but the ones I have in mind are:
'Foul brood disease of honey bees: recognition and control'
and if you can obtain a copy...
'Statutory procedures for controlling foul brood'.
The following is not my idea and the originator prefers to remain
anonymous, but I believe it is so good an aid to disease recognition
I have been promoting it a bee talks recently.
The first brochure mentioned has good pictures of bee diseases as far
ranging as chalkbrood to American Foul Brood and you cut these
pictures from the brochure. You will need two brochures as in removing
one picture you then destroy another on the opposite side. Having
removed them you paste them onto a piece of thin card and get the
whole lot laminated for much less than a pound.
Whenever you are suspicious of the condition of the larvae in the comb
it is easy to hold them side by side, not infallible, but a pretty
good guide I would suggest.
The second brochure contains a very nice picture of a healthy comb of
brood and I suggest you add this to the collection. Have look at it
occasionally just to get an idea what you should be seeing.
See Bee Estimation (editor)
Blane White of MN Dept of Agriculture
"The latest I have seen or heard on the subject is
that it [HMD] is due to a protein deficiency ( or pollen deficiency )
and proper nutrition quickly clears it up completely.
I will pass along an observation from our Canadian friends that half
moon seems to disappear from the bees they import from NZ. Just seems
to not be an issue in Canada at all."
Written... Winter 2001, Revised... 09 Aug 2002