Pests & Diseases

Bee Health

What might come as a surprise to a lot of people and to new beekeepers is the fact that bees are being threatened by diseases, pests & parasites and environmental issues.

All experienced beekeepers are fully aware of it and know that constant monitoring of their hives for health issues is a vital element of beekeeping. It is important to recognise what is troubling the bees to be able to take measures against it and to avoid the spreading of diseases to other hives.

You cannot just put a hive in your back yard and expect them to look after themselves, if you are going to take them from their natural environment you need to manage and look after them just as you would any other animal.

The first step is to recognise what the problem is, the Victorian Department of Environment and Primary Industries (DEPI) provides assistance to beekeepers and has created a number of Ag Notes on the different Pests and Diseases.

All reportable diseases must be reported to DEPI as soon as possible.

Healthy Bee Frame

bee with brood

Unhealthy Frame

SHB Larvae & Slim

beetle larvae and slim
Category
Sub Category
Name
DiseaseFungalNosema Apis & Ceranae
Chalkbrood
BacterialAmerican Foulbrood (AFB) (reportable)
European Foulbrood (EFB)
VirusesBlack Queen Cell Virus (BQCV)
Sacbrood Virus
Pests & ParasitesPestsAsian Honey Bee (AHB)
Braula Fly (reportable)
Wax Moth
Small hive Beetle (SHB)
Insects (ants, slugs, spiders, slaters, etc)
ParasiteVarroa Mite (reportable)
Tracheal Mite
Tropilarlaps Mites
EnvironmentalStressesMalnutrition & Starvation
Extreme weather conditions
Monoculture
Humans
Insecticides

Diseases – Fungal

nosema

Nosema (Nosema apis and N. Ceranae)

  • Disease caused by two species of of microsporidian parasites which can infect drones, worker bees and queen bees
  • Spores germinate in the bees gut and may cause a declining hive population, poor honey production, reduced brood production and dysentery in and around the hive
  • Infection results in reduced colony health and performance, as well as heavy winter losses
  • Both species are present thoughtout Australia, except N. Ceranae which is not present in WA
chalkbrood

Chalkbrood (Ascophaera apis)

  • A fungus which is ingested by bee larvae causing death by starvation
  • Symptoms include scattered brood with perforated capping.
  • The larvae dies after the cell is capped and becomes covered by a white/grey fungus, causing the diagnostic ‘mummies’
  • Incidence is usually greater when the colony is under stress due to cool weather or poor nutrition
  • Present throughout Australia, but not confirmed in NT

Diseases – Bacteria

AFB

American Foulbrood (paenibacillus larvae) - AFB

  • Fatal brood disease caused by a bacterium that is ingested by young bee larvae
  • Spores germinate in the bees gut and the developing bee usually dies at the pre-pupal or pupal stage
  • Symptons include irregular brood patterns, sunken and discoloured cell cappings with perforations
  • Decaying infected larvae may be roped to a distance to 2-3 cm
  • The bacterium is very infectious and remains dormant for over 50 years
  • Present throughout Australia, but not confirmed in NT or Kangaroo Island (SA)
EFB

 European foulbrood (Melissacoccus plutonius)

  • A brood disease caused by a bacterium that is ingested by honey bee larvae causing death by starvation.
  • Symptoms include spotted brood pattern intermingled with healthy brood, sunken and greasy cappings and a foul smell
  • Infected larvae die before the cells are capped in a twisted positionand become yellow-brown
  • Incidence is usually greater when the colony is under stress due to cool weather or poor nutrition
  • Present throughtout Australia, ecept in WA, NT and Kangaroo Island (SA)

Diseases – Viruses

BQCV

Black Queen Cell Virus (BQCV) (Cripavirus)

  • Virus which causes mortality in queen bee larvae or pre-pupae
  • Queen bee larvae or pre-pupae die after capping. The dead larvae or pre-pupas and the queen bee cell wall turn brown-black
  • Symptoms reflect the appearance of worker bee larvae killed by Sacbrood virus
  • Black queen cell virus may be transmitted by Nosema apis
  • Present throughout Australia, but not confirmed in NT
sacbrood

Sacbrood (Sacbrood Iflavirus)

  • A virus that affects bee larvae after consuming contaminated water, pollen or nectar.
  • Symptons include scattered dead brood and discoloured, sunken or perforated cappings
  • Infected larvae die shortly after capping and lave a yellowish appearance as the larva becomes a fluid filled sac. The shin of the dead larva changes into a tough plastic- like sac
  • Present throughout Australia, but not confirmed in NT

Pests

beetle on frame with bees

Small hive beetle (Aethina tumida)

  • Brown-black beetle that consumes honey bee eggs, brood, pollen and honey within the hive, as well as laying eggs throughout the hive
  • The hatched larvae chew through the combs causing the honey to ferment and the hive to become ‘slimed out’
  • Large numbers of small hive beetle can result in the death of the colony or the colony absconding
  • Has not been reported in NT or Tas but present in all other states of Australia.
destroyed frame wax moth

Wax Moth (Galleria mellonella & Achroia grisella)

  • Pests of weak and stressed colonies and combs in storage
  • Moths are a similar grey colour and tend to coexist in the same location
  • Moths prefer brood combs and eat wax, pollen and remains of larval honey bees, leaving behind silk webbing and silk lined tunnels
  • Larvae spin white silk cocoons on frames and hive body parts which can cause serve damages to the wooden parts of a hive
  • Wax moth can destroy an entire bee colony
  • Present throughout Australia
Braula fly

Braula fly (Braula coeca)

  • The Braula fly lives in the honey bee colonies and attaches itself to the honey bees mouth where it feeds on nectar and pollen
  • Has a preference for attaching itself to queen bees which can decrease the efficiency and egg laying capability of queen bees.
  • Braula fly larvae tunnel under honey cappings which give honey comb capping a fractured appearance
  • Is present in Tasmania but not on mainland Australia
Asian HB

Asian honey bee (Apis cerana Java genotype)

• Invasive and adaptive strain of the Asian honey bee (AHB)
• Similar appearance to the European honey bee, although is slightly smaller, has more pronounced stripes on its abdomen and has an erratic flying pattern
• AHB cannot be managed for honey production or pollination, due to it frequent swarming and tendency to abscond
• Robs European honey bees of their honey stores and competes for floral resources
• Currently only present in the Cairns region (QLD)

Insects

Uninvited Visitors, like ants, slaters and spiders.

Virtually every beehive in the field has the potential to provide shelter to a number of small creatures. Most of these uninvited visitors are a nuisance and don’t pose a serious threat to the bees.

Parasites

varroa on grub
multi varroa on bee

Varroa mite (Varroa destructor and V. jacobsoni)

  • External parasitic mites that feed on adult bees and the haemolymph of drone and worker bee larvae and pupae.
  • Detection possible by close examination of brood and adults or testing of adult bees.
  • Symptoms include deformed pupae and adults (stunting, damaged wings, legs, abdomens) Parasitic Mite Syndrome (PMS) and colony decline
  • Varroa mites can also spread viruses, further affecting the colony;s health and disease susceptibility.
  • Varroa mites currently do not exist in Australia, it is only a matter of time and when it does arrive it will be a major problem for all beekeepers.

Australia is the only country where Varroa Mite does not exist, it is a parasite of adult honey bees and honey bee brood. It weakens and kills honey bee colonies and can also transmit honey bee viruses. It will wipe out most hobby and many commercial beekeepers when it does arrive in Australia.

tropilaelaps mites

Tropilaelaps Mites (Tropilaelaps clareae and T. mercedesae)

  • External parasitic mites that feed on adult bees and the haemolymph of the drone and worker bee larvae and pupae.
  • Detection possible by close examination of brook or tesing of adult bees
  • Symptoms include deformed pupae and adults (stunting, damaged wings, legs, abdomens) Parasitic Mite Syndrome (PMS) and colony decline
  • Tropilaelaps mites can also spread viruses, further affecting the colony;s health and disease susceptibility.
tracheal mite

Tracheal Mite (Acarapis woodi)

  • Internal parasite of the honeybee respiratory system
  • Affects the honey bee’s capacity to breathe, resulting in weakened and sick honey bees which have a reduced lifespan.
  • Symptons include population decline, bees crawling on the ground and h=bees holding their wings at odd angles (“K wing”)
  • Accurate identification requires dissection and microscopic examination of the bees trachea.

Environmental Stress

Some of the issues honey bees are facing are stress related. Just like us, whenever bees are exposed to stressful situations or conditions it does affect their well being and health.

Health issues are causing further stress and when conditions do not improve the bee colony is on a downward spiral to extinction. A multitude of issues can increase the stress level, some of them created by nature and some created by us (human action).

Malnutrition and Starvation

Honey bees require a variety of pollen and nectar from different plant sources, to remain a healthy and strong bee colony. They collect pollen and nectar from flowering plants as long as it is available and what is not consumed during this time gets stored in comb cells. When conditions are good they build new comb to store more nectar and pollen. Bees use the stored surplus when there is insufficient nectar and pollen to collect, during winter, on cold or wet days. Once a bee colony has established a substantial food store and is left alone it will rarely run out of food but when they don’t have sufficient food this is when malnutrition and starvation can wipe out an entire bee colony.

The strength of a honey bee colony can be affected by

  • Extreme weather conditions (stops foraging)
  • Humans robbing the hives of surplus honey (insufficient nectar)
  • Plants not producing enough pollen or nectar (insufficient food available)
  • Monoculture, insufficient variety of pollen or nectar (lack of variety and food)

Insecticides

Insecticides have been developed to kill insects,  ” Bees are insects”. It should not come as a surprise that bees get killed by insecticides. How effective can an insecticide be, claiming to be “safe for bees” – safe for insects? – a contradiction in itself !
The use of insecticides in agriculture, in particular required for monoculture farming, is an attempt to reduce the damage to crop by insects. But by killing those “crop damaging” insects we also eradicate a great variety of other insects, among them our bees which are vital for crop pollination.
When placing beehives in or near an orchard or argricultural farms there is a fairly high risk that the bees get exposed to insecticides used during that time, or to plants that have been treated prior with seed treatment products. If not in the same orchard or farm, insecticides might have been used in one of the neighbouring orchards or farms – bees don’t stop at the fence!
With the ongoing development of new toxic chemicals, more powerful products are released on the market to “do their job”, the threat to bees is always present – and the list of these products is getting longer every year.
Some of the most powerful “weapons of mass destruction” are neonicotinoids, bees are killed by just walking on a plant that has been treated with this toxic chemical.

Monoculture

Our monoculture approach to agriculture where crops of the same kind are grown in large, concentrated areas are having an affect on Honey Bees. If the only source of food the bees can get is from the one crop grown in an area, it can lead to malnutrition, bees need a variety of different pollens and nectar, imagine only having access to one food source for weeks at a time.
One might argue that the pollination period is only for a short time, between three and six weeks, and during that time bees have also access to the pollen and nectar already stored in their hive. This argument weakens though when beehives are moved from one farming region to the next to pollinate large areas of monoculture crop at a time.
The Almond farms in the Robinvale area (Victoria) required 60,000 beehives for pollination in August 2008 and in 2014 requires 145,000 to meet the demand. Almonds only produce pollen and no nectar, it could be quite easy for a beehive to starve to death, bee need both pollen and nectar for survival.

Extreme Weather Conditions

In the 2013 spring season, the continuing weather pattern offered 3-4 days of warm weather with good foraging conditions, then a sudden temperature drop to 6-12°C with rain and strong winds for two weeks or more. This brought a sudden end to the foraging and the collection of nectar and pollen.
Some new starter bee colonies (swarms) simply ran out of food, causing a high stress level for the bees. In some cases new brood could not be kept at 35°C and simply chilled to death, in other cases the under-tempered brood got infected by a fungus causing Chalkbrood disease.
In extreme cases the entire colony simply starved and froze to death. Feral bee colonies with insufficient food stores do not survive and disappear quietly and unnoticed. It is a beekeeper responsibility to manage their hives and ensure that there is always sufficient food available to keep their hives strong and healthy.

Humans

Inappropriate beekeeping methods, i.e. bee farming, where hundreds or thousands of beehives are kept and managed with an industrial approach. Bee Farmers with 2,000 or 5,000 hives cannot provide the same attention, love and care for their bees as a beekeeper with only two, eight or twenty hives. One can only suspect that it does cause stress to bee colonies when they are handled as commodity rather than living creatures.
One might also argue that with bee farming the focus for the beekeeper shifts towards “what is good and efficient for me” as opposed to “what is good for the bees”. Watch the movie “More than Honey” to get an understanding of large scale bee farming, not a very nice thing to see.

bee on flower
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