The fear of antibiotic-resistant foul brood hung over an otherwise optimistic Saskatchewan Beekeepers Association convention.
“It’s maybe our biggest issue for the next 10 years,” said association president Christopher Warriner.
American foul brood is a bacterial disease that kills bee larvae in the hive. Producers have struggled with it, largely successfully, for most of the past century.
But the main weapon against it, the antibiotic oxytetracycline, or OCT, is no longer 100 percent effective.
For the past five years, American honey producers have been finding infections they can’t treat with OCT.
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The OCT-impervious disease strain has also shown up in Alberta and British Columbia.
Warriner said Saskatchewan beekeepers are worried because the disease will destroy a bee operation if not controlled. Producers have something to worry about if they lose their main control method.
“Suddenly, 20 percent of the hives are gone, 30 percent of the hives are gone, and bang, you’re out of business.”
Don Nelson, an Agriculture Canada bee researcher, is trying to find ways to combat antibiotic-resistant strains.
“It can be just as bad as varroa (mites),” he said.
“In some ways it’s worse, because the spore load is so heavy.”
Starts in the hive
Adult bees carry the disease into a hive’s larvae chamber. An infected larva that dies while the chamber is open will dry up and become a spore-filled scale on the bottom of the chamber.
Adult bees that clean up the scale transfer spores to another location.
A larva that dies in a covered chamber will putrefy. Adult bees will remove the cover and clean out the stinking mess.
Nelson said these larvae are brown and semi-liquid.
One way to test for American foul brood is to open a chamber with a dead and decaying larva and insert a toothpick.
If a long, ropy string of putrefying larva sticks to the toothpick, chances are it is infected with foul brood.
Producers may also notice a stench from a badly infected frame, Nelson said.
Often the only way to control the disease is to burn or otherwise destroy and remove infected frames.
While OCT kills most growing foul brood bacteria, it doesn’t affect the spores, which can live for up to 17 years on beehive frames.
Nelson said producers who hope to catch the disease before it catches them must do more inspections.
American foul brood hasn’t been on the top of producers’ minds for the last few years, Nelson said.
“We’ve been so preoccupied with the tracheal mite and the varroa mite for the last 10 to 12 years that our intensity of inspection for this has fallen by the wayside.”
Nelson said a couple of foul brood resistant bee lines were produced in the 1950s, but were not maintained.
Developing new resistant bee varieties might be one way to deal with OCT-resistant foul brood.
Another antibiotic could be developed to kill the disease, but Nelson said there are no others registered for use right now.
Researchers need to find an integrated pest management system for foul brood.
He has hopes that ongoing research on varroa mite control might also help with foul brood control.
Researchers are trying to develop bee lines that clean themselves and their hives more thoroughly, which would get rid of more mites.
It could also help bees get the spore-infected material out of the hive before the disease destroys them, Nelson said.
Researchers are also looking at irradiating frames to kill spores.
Warriner said his members are worried about American foul brood, but they’re also optimistic because honey prices are up.
Prices have risen 10 to 15 percent to about 85 cents per pound since the fall.
Prices hit a peak of $1.25 per lb. about five years ago. Last year they dropped to 71 cents, which is probably just above most people’s cost of production, Warriner said.
