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American Foulbrood

The most serious disease a hive can have

Spore forming

The vegetative stage infects larvae

It grows for about ten days and then turns into a spore

2.5 billion spores can exist in one (AFB) scale

It takes only about 10 spores fed to a one day old larvae for it to become infected 


            Irregular brood pattern (shotgun appearance)

Many cells are left open among capped brood

Perforated, sunken, sometimes greasy looking wet capped cells

Foul odor

Discolored larvae

Dried out scales adherer to lower cell walls

Pupal tongue may be present

Larvae die upright

Scales are difficult to remove

How it Spreads

Robbing behavior

Infected equipment


Infected honey and pollen



Rosiness test-- take a toothpick stir it into a sick larvae and if it stretches out like glue it is most likely (AFB)

 Foulbrood test kit

Send a sample of Honey free brood to                                                                                                                                                                                                                                                                                           Bee disease Diagnosis

                                                                                                       bee research Laboratory

                                                                                                         Bldg. 306 Room 316

                                                                   Beltsville Agriculture Research Center-East

                                                                                                            Beltsville, MD 2070


Terramycin and Tylan powder kills the vegetative stage but not the spores!!!

Lye bath and Paraffin dipping are both options but there is a risk of reinfection

Ethylene oxide kills the spores but few states still approve it. (it is known as a cancer causing chemical and doesn’t kill the spores in honey)

Gamma Radiation (impractical)

Put the bees on knew equipment, requeen, and feed or spray with a medicated syrup

BURNING is the most effective treatment. Kill the bees with soapy water at night. And them burn them. Then Burn the infected equipment and bury it.

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