Honeybee Health – Diseases

Diseases

There are a range of diseases that bees are affected by.
Most are spread through poor husbandry, in particular hygiene.  Identification is key to dealing with whatever problem you may face when you are doing an inspection of your bees.

AMERICAN FOUL BROOD (AFB) – notifiable to the National Bee Unit

Signs and Symptoms:

  • pepper pot pattern;
  • holes in the cappings;
  • dark cappings sinking to dark black scales
  • ropy goo when cell poked with matchstick
  • always evident after the cell has been sealed

Cause:

  • Bacteria:  Paenibacillus 
  • Spore forming; resistent to hot/cold even extremes; can remain dormant in old honey/equipment

Action:

  • Contact the NBU immediately
  • Test with kit from VitaEurope
  • Burn hive and contents
  • Alert neighbouring beekeepers and your association for support

EUROPEAN FOUL BROOD (EFB)

Signs and Symptoms:

  • pepper pot pattern
  •  yellow creamy goo in cell – melted down larvae
  • twisted yellow larvae
  • an unpleasant sour odour;
  • Loosely-attached brown scales
  • always evident before the cell has been sealed and does not rope when drawn

Cause:

  • Bacteria:  Melissococcus plutonius
  • Infected food is fed to larvae

Action:

  • Contact the NBU immediately
  • Test with kit from VitaEurope
  • NBU will advise if hives have to be burnt or treated using antibiotics
  • Alert neighbouring beekeepers and your association for support
  • As part of Integrated Pest Management (IPM) perform shook swarm every spring – changing of comb will reduce instance and is more effective than antibiotics
  • Stress is often a trigger – lack of food, water

Links:  Dave Cushman     NBU     Vita-Europe    Healthy Bees infomation

CHALKBROOD

Signs and Symptoms:

  • holes in cell caps
  • pepper pot brood pattern
  • fluffy white – sometime look like mouldy pollen (can be mistaken for EFB)
  • dead larvae swell up
  • sometimes have protruding mouth parts
  • harden grey or black or white in cell
  • cell sinks

Causes:

  • Fungal:  Ascosphaera apis

Action:

  • use Open Meshed Floors (OMF)
  • keep your hive well ventilated
  • requeening is an option particularly if the colony is not thriving – assess all other options first
  • Consider leaving feeder holes in crown boards open during winter (reduces moisture making spores less likely to develop
  • don’t allow colony to lack stores (pollen and honey)

SAC BROOD

Signs and Symptoms:

  • pepper pot brood pattern
  • infected larva turns to a pale yellow colour
  • as dries out turns a dark brown to black colour,
  • workers uncap the cells to expose them
  • discoloured, sunken or perforated cappings

Causes:

  • viral infection:  Iflavirus genus

Action:

  • Hygiene very important – clean equipment between apiaries and between hives
  • consider requeeening

BALD BROOD

Signs and Symptoms:

  • uncapped or partially capped cells caused by tunnelling wax moth larvae

Causes:

  • Wax moth larvae – both Achroia grisella (lesser) and Galleria mellonella (greater)

Action:

  • keep strong colonies
  • manage hygiene – keep boxes clean – eggs laid in crevices!
  • deal with wax moth with new comb/foundation

baldbrood caused by wax moth

Other brood viruses include Acute Bee Paralysis Virus (ABPV) and Chronic Bee Paralysis Virus (CBPV).

Links:  NBU   Vita-Europe

Advertisements