European foulbrood (EFB) is a serious, bacterial disease of honeybee brood now found throughout the world. The infected larvae appear twisted in their cells, often forming an unnatural C-shape along the sides or in the bottoms of the cells. Their tracheal system tends to stand out and appear silvery. Sometimes the gut will be visible through the translucent body tissue. The infected larvae turn yellow and then brown. Eventually they dry to rubbery scales within the cells. Note that these cannot be “roped out” with a matchstick as with AFB. These drier scales can be more easily removed by the worker bees and thus this disease is less easy to spot.

Signs of European foulbrood include:

  • dead larva collapse, turning yellowish-brown
  • brood pattern appears patchy and erratic
  • an unpleasant sour smell

If you suspect your colony has European foulbrood you must:

  • contact the NBU office or your local bee inspector immediately
  • close the hive
  • disinfect beekeeping equipment before examining other colonies
  • not remove any colonies, equipment or honey from the site until the disease, if confirmed, has been controlled