EFB ACK!

Earlier this summer, we noticed our new package of bees wasnt building up as quickly as it should, and the brood pattern wasnt full and solid like it would be in a healthy colony.  We started looking closer at the combs, and noticed a few things.  Most of the uncapped cells all had eggs or larvae in them, so the queen was laying fine.  But many of the uncapped larvae didnt look quite right--some were sort of discolored and laying at the back of the cells; others started to extend out toward the front of the cells, but were slightly twisted, as if they had a stomach ache. In short, a lot of our brood frames looked like these and these.  Sounds like trouble.  Not trusting our limited beekeeping experience to officially diagnose the problem, we decided to send a comb sample to the USDA bee lab, where they test it for free and tell you what disease your bees have (if any).  A few weeks later, the results came back: our bees had European Foulbrood (EFB).  Oh no!

Heres the old brood comb, with the sample we cut out to send to the Bee Lab.  Although they only ask for a 2" x 2" square, we cut out a section to fit a small USPS box instead.  Dont want them to wish they had more to test!

So what are our options for treatment?  While EFB is no walk in the park to get rid of, its not quite as bad as its evil sibling American Foulbrood (AFB) in that it doesnt form spores.  For AFB, the only treatment is to kill the bees and burn them along with the frames and comb (hive boxes and other equipment the bees have come into contact with can sometimes be sterilized by high heat or bleach).  For EFB, there are a few more options (and here):

1. Do nothing, since in a strong hive, symptoms will often clear up when the nectar flow is strong.
2. Treat with the antibiotic Oxytetracycline (trade name Terramycin).
3. Re-queen, since a disruption in the brood cycle will often clear up symptoms.
4. Use the "shook swarm" method to restart the colony on uninfected combs in a new hive (this also disrupts the brood cycle).
5. Kill the bees and burn or sterilize everything, same as for treating AFB.

Of these options, we had already been trying #1 for a while, and it clearly wasnt clearing up.  Were trying to minimize chemical treatments of our bees, so #2 wasnt a great option, either.  #3 would be ok, but it seems like we could get the same effect by #4, which was preferable to us since our queen seemed to be laying well and we already had everything we needed.  #5 is obviously a last resort, and we werent there yet!

So, shook swarm it is!

The general operation is simple, and shown here: were just taking all the bees from the old hive and shaking them into the new hive.  A few tricks that arent shown in the video: the new hive should have a queen excluder on the bottom (actually functioning as a queen includer) so that she doesnt have the opportunity to decide she doesnt like the new digs. Also, the chances are good that shell end up in the new hive if were efficient in our shaking operation, but we can increase the odds by spraying the frames down with sugar water to reduce flying bees before shaking them, or if we wanted to be really sure, we could find the queen and catch her, and then install her in the new hive once the rest of the bees are in there.

Also, in our case, since were trying to clear up EFB, the new hive should just have foundation and not already-drawn comb so that the bees have a chance to sort of purge their system before they have to feed new brood. Some sources recommend holding off on feeding them for a few days for the same reason.

After a couple weeks in the new hive, theyve started drawing out comb and generally looking healthier.  Can you find the queen in this picture?  Her name is Waldo.

If we blow a little smoke on them to clear the bees away, we can see that the brood pattern looks a lot more full than it did in the old hive.  Time will tell if they can build up enough to make it through the winter, but theyve got a better chance now than they did before!

Stay tuned to find out what happened to all the old frames, comb, and the honey they had stored.

Have you dealt with EFB before?  Have you done the shook swarm method with your bees?  How did it go?  Let us know in the comments section below!

Related Posts by Categories