Bee Diseases


Honey bee diseases cause significant losses of bees, bee products and pollination activities. Four of the major diseases contributing to these losses are American foulbrood (AFB), European foulbrood (EFB), nosemosis and chalkbrood. The correct diagnosis of these diseases is important, especially in differentiating AFB from EFB, as each disease requires a different control regime. All four diseases are notifiable in NSW.

AFB caused by Paenibacillus larvae,EFB caused by Melissococcus plutonius and chalkbrood caused by Ascosphaera apis are diseases of honey bee brood (larvae and pupae) whereas nosemosis, caused by the parasitic fungi Nosema apis and/or Nosema ceranae,is a disease of adult bees.

Diagnosis and tests available


American foulbrood: The diagnosis is strongly supported by clinical signs of disease. AFB can be confirmed by the microscopic examination of diseased larvae in smears for the spores of Paenibacillus larvae. Honey testing for these spores is also a useful means of tracing infection sources to the hives of origin from which positive honey samples were collected.

European foulbrood: The diagnosis of this disease is also strongly supported by clinical signs of disease. EFB can be confirmed by the microscopic examination of diseased larvae in smears for the bacterium Melissococcus plutonius and/or the spores of Paenibacillus alvei a common secondary bacterial invader in cases of EFB.

Chalkbrood (PDF, 225 KB) is the only significant fungal disease of honey bee brood. The diagnosis is strongly supported by clinical signs of disease and can be confirmed by the microscopy of diseased brood.

Nosemosis: The only accurate means of diagnosing nosemosis is the microscopic examination of the gut of infected bees.

Tests available


Sample(s) required

Days of the week test is conducted

Turnaround time1

American foulbrood (AFB) and European foulbrood (EFB) - microscopy

Larval smear(s) or section of brood comb containing diseased larvae

Monday - Friday

1-2 days

Paenibacillus larvae (AFB) culture on honey

Minimum 100 ml (145g) honey

Monday - Friday

Up to 12 working days

Nosemosis – microscopy2

10-25 adult bees

Monday - Friday

1-2 days

Chalkbrood - clinical signs/microscopy2 Diseased brood (mummies) Monday - Friday 1-2 days

1 Turnaround times are provided as a guide only. For specific information about your submission please contact Customer Service.
2 Testing is not NATA accredited

Specimen requirements

Find details on how to collect/prepare samples (PDF, 318.08 KB).

Larval smears

  • For EFB and AFB:
    • Prepare smears from larvae showing signs of disease (up to 4 larvae per smear).
    • Air dried smears should be individually wrapped in paper and sent between two hard cardboard sheets held together with tape or an elastic band. Do NOT send two smears in contact with each other.

Diseased brood

  • For EFB, AFB and chalkbrood
    • Submit an approx. 5 x 10 cm piece of brood comb containing diseased larvae/pupae wrapped in paper towel and packaged in a strong cardboard box. The comb must not contain honey and crushed combs may not be suitable for diagnostic analysis.
    • If unable to send the comb on the day of collection, the comb should be refrigerated until being sent.
    • Thoroughly clean any tools used to remove the piece of brood comb to avoid spreading disease to other hives.

Honey samples

  • For AFB ONLY
    • Honey samples should only be submitted to trace AFB infections. Submit a minimum of 100 ml  of bulk honey, preferably from an extraction of multiple hives. Do NOT scrape honey from individual frames or send honey contaminated with debris. If you own a small number of hives it is best to examine the hives for disease signs rather than submit honey samples.
    • Find out more information about honey testing.

Adult bee samples

  • For nosemosis
    • Samples for diagnosis should be collected by gathering 10-25 live or freshly dead adult bees from the hive entrance or from the top bars of the frames. Young nurse bees on brood combs are unsuitable for examination.
    • Place live bees in a plastic container with some queen candy and forward to the laboratory by the fastest available means.

Further information

For further information on managing established bee pests and diseases please see the DPI Honey bees web page and the latest PrimeFact

To submit a specimen for diagnosis please complete the Bee Disease Diagnostics Form (PDF, 472.8 KB).