American Foulbrood – Deceptive and Deadly

American Foulbrood has paid a visit to a hive one of my bee yards.  It is the first time I have had a case of Foulbrood in over ten years of beekeeping  The hive has been destroyed.  The frames made a very nice fire.  The boxes got burned too, but that was an error – my husband got a bit carried away.  The tops and bottom screens have been scorched and wiped with bleach solution.


I’m a fan of the Bee Research Laboratory in Beltsville, Maryland –  and their diagnistic servies (  Whenever I suspect something’s wrong, I send a sample.  Until this time it has always been varroa or nosema.


All my equipment is bought new.  No frames in the hives are over five years old (they are dated).   There are a few other beekeepers near-by, and there are feral colonies of honeybees in the area.  American Foulbrood can originate from a beekeeper’s hive or feral hive.


Honeybee brood dead from AFB

American Foulbrood

Honeybee brood comb infested with varroa mites

Varroa Mite Infestation

American Foulbrood can look like brood that has been long dead from mites, if the AFB in the post-ropy “dry” stage.   Brood from a varroa infestation can look like AFB, if the hive has been dead a while (no living bees or mites).  The above image is a USDA image which shows living brood. In a long dead hive these would be all dried up.   This can include depressed cappings, holes in cappings, and even an odd smell.

It’s easier to tell apart if either problem is in the early stages. Mites will be present in a mite infestation. In AFB the brood turns brown and if a thin stick or pin is inserted, the remains will draw out like a long string).

The short story is that I had three hives that looked like mite kill, but one had an odd odor to it.  Ah ha! Foulbood.   Frames from those hives were identified by a friend who has been beekeeping for over 30 years as AFB.  It turned out that hive, the one that smelled, was dead from varroa mites, not AFB (Bee Research Lab results).

However another hive I had tested did show positive for AFB.  It didn’t smell.


AFB can  fool the most experienced beekeepers.  Always check with the Bee Research Lab.


Or always check with the bee lab before you destroy anything

I was clearing out the seven dead hives from the past winter.  All of them had been strong hives over the summer with picture perfect brood patterns.  These teaming hives had gone into winter with full stores.  Four of the hives died by queen failure.  Three had other stories.

One hive in my first yard looked like death from varroa mite.  IMAGE.  Sad, but these things happen, not every “resistant” queen and her mates are perfect.  But this one had a different odor.  It was not the smell of sulfur, or “old socks”, or anything terribly pungent.  It just smelled dead. (If you live in the country where you periodically find that a mouse has passed away in storage area of your pick up, your tractor’s battery compartment, or that tool cupboard you forgot to shut, you’ll know the smell).

The “roping” test for American Foulbrood was not applicable here; these hives had been dead for months.  Scale was there, but that can be deceptive, as you’ll soon read.


I was going to visit a beekeeper friend the next day, with over 30 years in beekeeping experience.  He said “bring some frames down, I’ll look at them.”  I did and he said “Foulbrood.”

Back at the farm, I cut a square of the brood out of one of the frames, wrapped it in paper, put it in a box and put it in my office.  The hive was isolated, and all entrances were closed.

I then checked my records: Where did this hive come from?  Where was the queen from?  Were there any notes on anything odd in this hive last year?  It turned out that the hive was a split from another bee yard with an open-mated queen.  In fact, it was a split from a hive that had died during the winter and was on the next days autopsy schedule.


That hive and the dead-out next to it looked like a mite kill, but they had the same “dead” smell.  By now, I was smelling this everywhere: the kitchen, the libary, the gas station. Those hives got the same treatment as the other, including cutting out a sample.

All the hives were destroyed.  Fire, scorching, bleach…

THE EXPERTS SPEAK– and do diagnostics:

Then I posted the samples to the Bee Research Laboratory.  In hindsight it would have been better to post, wait for results and then destroy.

One hive did show Foulbrood, but NOT the hive that was indentified as Foulbrood by the an experienced beekeeper


1) Wait until you get your results back to destroy any hive.  Do isolate and lock up the hive in the mean time.  If it has living bees, make sure those bees cannot get out of their “lock up”.   It took about 10 days to get the results from the Bee Lab.

2) A varroa mites deadout can look like Foulbrood to even the most experienced beekeeper.  Yes, even down to the “scale” of dead larvae.  This hive probably died sometime in the late fall or early winter

3) Foulbrood can look like a varroa mite kill.  It might smel, but do not depend on it to smell like sulfur, rotten eggs, dirty socks. Don’t go with the smell.

4) To beat a dead horse (or hive in this case) : When in doubt send samples to The Bee Research Laboratory (  At this time the service is free, but even if they do start charging (these are hard times), it is well worth the money.  If folks who have been keeping bees for decades can get it wrong, we all can.

So now it’s just wait, watch, and monitor.  Other hives may have visited the infected hive or the location that the infected hive visited.  A bit nail-biting, but at least there was no robbing in the affected hive.  All my hives have strong stores left from last fall, and the rain has kept them in.  I’ll let you know what happens.

That’s the news from Brookfield Farm in Maple Falls.


About brookfieldfarmhoney

Brookfield Farm, a small off-grid apiary in Maple Falls, WA focuses on the beauty and bounties of Washington’s wilderness. I sell honey from our bees, whose naturally-treated, antibiotic-free hives are home to bees who fly Washington’s mountains and farmlands. Herbal salves and lip balms from Brookfield beeswax. Delicately infused honeys and vinegars. Varietal honeys from independent Washington beekeepers. Karen Edmundson Bean: beekeeper, photographer. Her love of the wilderness inspires her to discover new ways of bringing the wonders of nature to others. Brookfield Farm : the tastes, textures, sounds, and images of nature.
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12 Responses to American Foulbrood – Deceptive and Deadly

  1. Natalie says:

    A very helpful post, and I’m sorry you had to deal with this! But I will definitely remember it in the future if I have have similar issues. I hope I don’t, but I know these things happen. 😦

    • I’m glad it was helpful. It is a drag, but it’s all part of the joys of farming wild animals – you just never know where they’re going to go and what they’re going to bring home.

  2. Hey there a good story and very interesting. Did your hive have any of the ropey signs ?

    • Yes, that was the final, horrid moment. I kept looking for scale – and I still don’t really see it. And the dead brood really do look quite like a varroa hit. Smell, well, it sure wasn’t “dirty socks” – but then I wonder about my sense of smell. So ropy was the best bet. Only problem: I don’t pull my hives apart from November to February (not yet this year, still snowing here) – so the first hive it was in had been dead for a few months – no ropy… In the end I got some of the test kits, and kept using that. By the time I got done, I could actually tell by look and smell the ones that had AFB. On the plus side, the notes I had let me trace the hives: they were all splits off of what had been a successful hive for 3 years, but somewhere along the way they had lost (if they ever had) a resistance to AFB. A good learning experience, but one I never hope to repeat – it is so depressing to kill bees and burn frames (flaming the rest isn’t as sad).

  3. PoodooPosse says:

    10/10/12 Yesterday, a local entomologist confirmed the diagnoses that our 2 hives have AFB. We were told to burn everything (may need a burn permit but check with the AG commission) and discard all tools to be extra safe. For next year, do you recommend moving the hives location? A website said the spores can live 70 years–arghhh. Also, on frames with no brood, is the honey OK to spin?

    • My heart so goes out to you. I had a few go down this year with AFB again (ahhhhh!)
      First: DO NOT SPIN THE HONEY. It will put AFB spores all over the place. You have to burn the honey frames as well as all of the other frames (depressing, I Know). VERY IMPORTANT: when you burn those frames, you MUST keep your other bees off that honey (I work out of a truck with a well-sealed back canopy).

      Burning: Burn all the frames (if you use plastic, hit the wax with a garden flame tool, but don’t burn plastic, it’s toxic, then wrap the plastic frames that have melted wax in plastic and seal). You can char the boxes, tops, and bottoms, and any other wood pieces with the garden flame thrower (as I call it).
      Tools: you can flame your tools or boil them.
      Clothes: Wash as hot as you can – or put them in boiling water.

      Moving the hives might help, but probably not. AFB spreads by the bees visiting other hives, either drones moving around, or from robbing. If, as the AFB hive was dying, the hive’s defenses were low, other bees may have entered and taken honey – AFB is in the honey too. So they’ve taken it home and will later eat it. This could mean you’re in for more AFB, or possibly not:

      Why possibly not: because most hives have low levels of AFB in them (the disease has been around for over 100 years) but they all do not die of it. Resistance is part of it. Weather can be part of it – stressed bees can be more affected.

      Long answer to short question: Move the hives? I don’t think it will help, but if you can, it’s worth a shot. If you have other hives infected, they will be dead by spring. Monitor the hives closely this winter – don’t let other bees get into deadouts.

      Good luck. You can beat this, but it will take time.

      • PoodooPosse says:

        Thank you for taking the time to write. We are in Santa Clara County CA (I sent your reply to the former pres of the local bee guild) and the Ag Commissioner also said to burn not bury. The fire department said Air Quality Control prohibits ANY such burning even for fire department training purposes. We found someone with an agriculture burn permit (not this county) for the frames and a beekeeper with a blowtorch for the supers etc. He said you scorch until the propolis bubbles. We’re starting over in 2013. Last year we used swarms, this year we’ve ordered 2 queens and 2 bee packages. We are very Thankful for our bees and so much more. Wishing you a very happy, healthy Thanksgiving.

        • AFB’s bad enough, but it must be far more troubling trying do deal with disposal in a no-fire area.  Is it possible that your local fire dept would burn the frames for you?  But yes, scorching is great and I love your discription “until the propolis bubbles” perfect. I’m going to steal that line.  It’s what one has to do if one has plastic foundation (as burning plastic is toxic).  But after the sorching, it’s best to wrap and seal (with tape) the frame in plastic for disposal: the smell of the burnt honey/propolis/wax brings bees (go figure).  I’m glad you’re going to keep going.  The most challenging thing about beekeeping is keeping them alive and healthy.  Good luck – it’s all one long adventure, isn’t it?

          On Thu, 15 Nov 2012 16:02:41 +0000, “Brookfield Farm Bees & Honey Blog”

        • PoodooPosse says:

          Hope you had a great Thanksgiving. Our mentors have friends with a burn permit and they dealt with AFB hives (our mentors and their friend.) The fire department was no help because of air quality control restrictions. Not only couldn’t they burn our bits, our fire department is no longer allowed to train with any live fires. BTW, our mentors have been beekeepers for over 40 years and her dad was a beekeeper, too. She said in all the years they have only had AFB twice and to not give up, one bad year won’t necessarily be repeated.

        • The fire dept can’t train with real fires!? That’s scary.  AFB seems to come and go.  There’s AFB up here, and in the county south of us there is a report of EFB.   I have this feeling that 2 things are going on 1) that perhaps bees became less resistant to AFB and 2) it’s been around, but people are relectant to talk about it, thinking they’re at fault.  As you know, it’s not the beekeeper’s “fault” if the bees bring it home, only if the beekeeper doesn’t deal with it.  I’m glad you have such wonderful mentors, that makes beekeeping so much easier.  Yea, never give up – sometimes it’s 2 steps forward one back I’ve had a few 2 forward, 3 back as well, but on average I’m moving forward.

          On Sun, 25 Nov 2012 00:37:21 +0000, “Brookfield Farm Bees & Honey Blog”

  4. Jack Simpson says:

    I recently had the same experience with 2 of my hives, so depressing have to burn them. I had 2 other hives nearby and a few months have passed and thankfully they’re still going strong which is a relief considering I took a long time to seal up the dead colonies.

    • I know what you mean. I think I howl “noooooo!” when I find AFB. You would think that after over 100+ years of it being around, someone could come up with a viable, natural solution (other than a blow torch and pounds of dead bees). Glad to hear the AFB didn’t spread in your yard.

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