Nosema is caused by the nosema apis microbe.

Age of brood affected

Adult bees including:

  • workers
  • queens
  • drones.

Infection method

Adult bees ingest nosema spores from:

  • contaminated food or water
  • food exchange with other bees
  • cleaning contaminated combs.


These symptoms may indicate nosema infection:

  • Bees unable to fly. They may crawl on the ground with their hind wings at an unusual angle.
  • Greasy abdomen.
  • Hives may be covered in faecal matter due to dysentery.
  • Dead bees at the hive entrance.
  • Reduced colony population.

Most symptoms of nosema apply to other diseases. Diagnosing nosema from symptoms can be difficult.


The following steps can reduce risk of nosema:

  • Place hives in sunny areas. Hives in the sun that are sheltered from cold, wind, and rain have much less chance of developing nosema.
  • Pack colonies in a small space for winter. They will be kept warmer which reduces risk of nosema developing. Reduce colonies to single or 2-storey hives.
  • Replace old, dark brood combs. Spores will be reduced within the hive.
  • Make high quality pollen available nearby to reduce any protein deficiency.
  • Avoid stressing the colony from early autumn onwards.
To reduce the losses from nosema:
  • provide appropriate nutrition
  • place young queens in hives with large populations
  • use new combs regularly
  • place hives in dry, sunny locations.

Diagnosing nosema

Send 30 sick or freshly dead bees from the hive entrance or top bars of the frame for testing. Place live bees in a cage or jar with holes in the lid and some queen candy. Newly dead bees can be sent frozen.

Send samples to:

Apiary Unit
Primary Industries and Regions SA
33 Flemmington Street
Glenside SA 5065
Page Last Reviewed: 22 Feb 2018
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