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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

  • Drifting

  • Infected honey and pollen

  • Swarm     



  • 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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