Frame of brood infected by ascphaera apis, chalkbrood. Photo courtesy of Bee Informed Partnership.

Battling honey bee chalkbrood an expensive, maddening affair

We’ve had our hands full this year, what with the exceptionally early spring and the unusual advancement of bloom times. Our blueberry and raspberry growers called us in early, and the wild blackberry flow that we all depend upon in the Fraser Valley for our honey is just as early.
But what’s been equally troubling for us is a particularly severe outbreak of chalkbrood, almost exclusively limited to the packages of bees we imported earlier this year.
It’s a well-known fact that chalk brood, caused by a fungus called ascosphaera apis, can be a problem with packages of bees imported from New Zealand and Australia. I don’t know the exact reason for this, but have been told it may have something to do with the flipped season. They aren’t the only source of this fungus, and it primarily makes its appearance in the spring and fall.
But, at least in B.C., the presence of chalkbrood appears largely tied to imported packages.
In the past, we’ve had one or two packages show chalkbrood. But this year, we found that more than 50 per cent of the packages we ordered out of New Zealand had the fungus, and within weeks we were seeing frames shotgunned with the dead mummies of larvae. It was so severe that the bottom boards were littered with piles of mummies; not a happy sight when you are spending $180 a package and what you end up with is weak bees and an infected hive.
A commercial beekeeping colleague of mine told me last night that he’d frankly rather have European Foul Brood than chalkbrood. When someone says that, you know the problem is severe.

Closeup of chalkbrood-infested brood frame. The white mummies are the remains of larvae infected with aschophaera apis, a fungus. Photo courtesy of University of Minesota.

Closeup of chalkbrood-infested brood frame. The white mummies are the remains of larvae infected with aschophaera apis, a fungus. Photo courtesy of University of Minnesota.

Chalkbrood doesn’t kill a colony. But it can severely retard the growth of the hive and that itself is bad enough; it steals the economic value of the hive and leaves the beekeeper with problems, rather than productivity.
There is some research that suggests the prevalence of chalkbrood can be linked to poor availability of pollen. The U.S. Department of Agriculture has also done extensive research on chalkbrood as it affects the alfalfa leafcutter bee, a cousin to our honey bees.
The B.C. Ministry of Agriculture also has a useful fact sheet on common diseases, with a section devoted to chalkbrood. The Bee Informed Partnership also has a good section on chalkbrood.

Chalkbrood mummies at the entrance of a hive, where bees have dragged them. Photo courtesy of Bee Informed Partnership.

Chalkbrood mummies at the entrance of a hive, where bees have dragged them. Photo courtesy of Bee Informed Partnership.

There is no “treatment” for chalkbrood. The cure is both simple and severe: pinch the queen and add in a couple of frames of brood from a healthy hive to help the new queen. Clean the bottom boards and remove severly-infected frames to reduce the spread of the fungal spores
But this is also an expensive option. Another $40 for a queen (prices are up because of a shortage, of course!) and the diversion of frames of brood that could otherwise be used to build up colonies for honey production. For us, that meant nearly $1,000 in extra costs in replacing every queen in our imported stock. We pinched nearly every NZ queen regardless of whether they had chalkbrood or not, just as a precaution.
It was so maddening to find such a waste of resources that we’ve likely sworn off of ever buying packages out of New Zealand again. Not until the beekeepers there figure out how to produce bees without shipping us the fungal spores too.

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One Response to Battling honey bee chalkbrood an expensive, maddening affair

  1. Rob August 10, 2015 at 5:11 pm #

    Interesting post. I am trying to decide if one of my colonies here in NB has chalkbrood. It was slow to build, and today I noticed an unusual blackish frass deposit on the screen sheet, together with what appears to be mummies. Some are all white but others have a covering of black that under a 10x lens is revealed to be an encrustation of tiny black nodules a bit like a truffle.

    I don’t follow the logic of killing the queens unless the disease is transmitted *in* the eggs (as opposed to on them)? Presumably spores will be on all the bees, comb etc.

    Rob