Nosema staining on the outside of a bee hive

Nosema is both the name of a condition and the organism which causes it. In the U.S. we have two species, Nosema apis and Nosema ceranae.

  • Both species are a unicellular fungus which resides in the gut of the bee

  • The parasite has a polar tube that penetrates cells of the bee

  • Injects the necessary elements for reproduction into the cell.

  • Inside the cell of the bee’s gut, Nosema reproduces by forming spores

  • Spores are passed within the bee’s waste.

  • Nosema Apis is most problematic in the winter and spring
  • Bees will begin to expel waste in the hive and on the outside
  • Brown spotting on the outside of the hive will appear

  • Nosema ceranae can affect a hive at any time of the year
  • Can cause rapid colony decline
  • No symptoms will be present

Both forms of Nosema are treatable with Fumagilin-B. Fumagilin-B is an antibiotic which restricts the “firing” of the polar tube. If the parasite is unable to attach to the cells of the bee’s gut it cannot reproduce.
Researchers now recommend treating with Fumagilin-B Spring and Fall.