30:02
Honeybee Diseases 2
Renel Sandro Saint Jour
Overview
This video explains common threats to honeybee colonies beyond direct predation, focusing on disease transmission through behaviors like robbing and drifting, and detailing specific ailments such as European and American foulbrood, sac brood, and K-wing syndrome. It emphasizes how these issues, often microscopic or behavioral, can devastate a hive and spread rapidly through an apiary. The content also provides practical advice for beekeepers on recognizing symptoms, managing risks, and implementing preventative measures to maintain colony health and productivity.
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Chapters
- Robbing occurs when bees from one colony steal honey from another, often during nectar dearths, weakening or destroying the victimized hive.
- Robbing is a highly efficient vector for spreading diseases like foulbrood and viruses to the robbers' home colony.
- Drifting is when a forager bee returns to the wrong hive, usually due to close spacing or disorientation, and can spread diseases and unbalance hive populations.
- Signs of robbing include frenzied traffic, fighting bees, wax flakes, and a lack of pollen on returning foragers, while drifting is more subtle and accidental.
Understanding and preventing robbing and drifting is crucial because these behaviors, while natural, can lead to significant disease transmission and colony loss, impacting the entire apiary.
Robber bees tearing open wax cappings to steal honey from a weaker hive, potentially carrying pathogens back to their own colony.
- Foulbrood refers to bacterial infections targeting bee brood (eggs, larvae, pupae), with two main types: European Foulbrood (EFB) and American Foulbrood (AFB).
- EFB, caused by Melissococcus plutonius, affects unsealed larvae, does not form spores, and is generally manageable without colony destruction.
- AFB, caused by Paenibacillus larvae, is far more dangerous due to its highly resistant, decades-long surviving spores, often requiring colony destruction.
- Symptoms differ: EFB larvae twist and melt, appearing yellow to brown with a sour odor; AFB larvae turn into a 'ropy' brown mass and dry into hard scales full of spores.
- Both spread through contaminated food, equipment, robbing, and drifting, but AFB's spores make it exceptionally persistent.
Foulbrood diseases are among the most destructive threats to bee colonies, and recognizing their distinct symptoms and transmission routes is vital for effective management and preventing widespread apiary devastation.
The 'ropiness test' for American Foulbrood, where a stick inserted into a suspect cell and pulled out stretches into a gluey thread.
- Sac brood is a viral disease caused by the Sac Brood Virus (SBV), affecting larvae and preventing them from pupating.
- Infected larvae die in a sack-like skin, appearing stretched out, shiny, translucent, and later dark and brittle.
- The virus spreads through oral transmission by nurse bees, communal feeding, and potentially exacerbated by Varroa mite infestations and environmental stressors.
- While rarely causing total collapse, SBV weakens colonies by hindering population growth, especially during critical spring periods.
- Strong, well-managed colonies can often overcome SBV with support like requeening, improved nutrition, and stress reduction.
Sac brood, though less dramatic than foulbrood, can quietly undermine a colony's strength and growth potential by disrupting the development of young bees.
Dead larvae found in capped cells, stretched out on their backs with heads raised, resembling a water balloon due to the sack-like skin.
- K-wing is not a disease itself but a symptom where a bee's wings become uncoupled, resembling the letter 'K', rendering the bee unable to fly.
- It is often linked to viral infections, particularly Chronic Bee Paralysis Virus and Deformed Wing Virus, and is strongly associated with high Varroa mite loads.
- Environmental stressors like poor nutrition, chemical exposure (pesticides, ammonia), and overcrowding can also contribute to K-wing.
- Affected bees appear otherwise healthy but walk instead of fly, indicating underlying stress or infection within the colony.
- Management focuses on addressing root causes: aggressive Varroa control, ensuring good nutrition, reducing chemical exposure, and requeening weak colonies.
K-wing serves as a critical visual indicator that a colony is under significant stress, often from Varroa mites or viruses, prompting beekeepers to investigate and address the underlying issues.
Seeing bees crawling on the hive entrance with their forewings extended to the sides and hind wings lowered, unable to achieve flight.
- Beekeepers must be vigilant observers, recognizing subtle signs of disease and stress in their colonies.
- Preventative measures include smart apiary design (spacing hives), entrance reduction for weak colonies, proper feeding times, and maintaining good hygiene.
- Regular inspections for abnormal brood patterns, ropiness, or K-wing are essential for early detection.
- Controlling Varroa mites, ensuring adequate nutrition, and choosing hygienic or mite-resistant queens are key long-term strategies.
- Reporting confirmed diseases like AFB is a legal and ethical responsibility to protect the wider beekeeping community.
Proactive management, diligent observation, and adherence to hygiene practices are the most effective tools beekeepers have to protect their colonies from devastating diseases and ensure the health of the entire apiary.
A beekeeper reducing the entrance size of a weaker hive during nectar dearth to prevent robbing attempts.
Key takeaways
- Robbing and drifting are natural bee behaviors that can inadvertently spread diseases and weaken colonies.
- American Foulbrood is a highly destructive, spore-forming bacterial disease requiring colony destruction, while European Foulbrood is generally more manageable.
- Sac brood virus prevents larval development, leading to sack-like remains and hindering colony growth, but strong colonies can often recover.
- K-wing syndrome is a symptom of underlying stress, often linked to Varroa mites and viruses, indicating a need for immediate management intervention.
- Effective beekeeping relies on constant observation, early detection of subtle symptoms, and consistent application of preventative management practices.
- Varroa mite control is paramount, as these mites weaken bees and act as vectors for numerous viruses, exacerbating colony health issues.
- Maintaining good hygiene, proper apiary setup, and understanding disease transmission routes are crucial for preventing outbreaks.
Key terms
RobbingDriftingNectar DearthEuropean Foulbrood (EFB)American Foulbrood (AFB)SporesSac Brood Virus (SBV)K-wing SyndromeVarroa MitesBrood
Test your understanding
- How do robbing and drifting behaviors contribute to the spread of diseases within an apiary?
- What are the key differences in symptoms and management between European Foulbrood and American Foulbrood?
- Why is Sac Brood Virus considered a chronic threat, and what factors can cause it to flare up?
- What is K-wing syndrome, and what are the primary underlying causes that beekeepers should address?
- What are the most critical preventative measures a beekeeper can implement to protect colonies from diseases like foulbrood and viral infections?