Do you recognise this disease? Explain what you see.
- European foulbrood, a bacterial brood disease.
- Banded brood associated with wax moth.
- Chalkbrood, a fungal brood disease.
- Nosemosis affecting mainly adult bees.
- Deformed Wing Virus: DWV, a viral disease.
- American foulbrood, a bacterial brood disease.
- Healthy colony with regular brood.
Show answer
Correct answer: 5.
Deformed Wing Virus: DWV, a viral disease.
Why?
Deformed Wing Virus, or DWV, is a viral disease of the bee. The most visible sign is the presence of bees with atrophied, crumpled, or poorly unfolded wings.
One may also observe bees with a shortened body, weakened or unable to develop normally. Some die already in the cells before emergence or shortly after leaving them.
DWV is strongly linked to infestation by Varroa destructor. The varroa mite actively transmits the virus and can turn a barely visible infection into a major health problem for the colony.
What to understand
The presence of bees with deformed wings should bring to mind varroa pressure that is too high or poorly controlled. The virus can be present in the colony without visible symptoms, then become problematic when the varroa infestation increases.
Visual diagnosis relies above all on the emerging or adult bees. Unlike the foulbroods or chalkbrood, DWV is not recognised first by the appearance of the larvae, but by the deformations and weakening of the bees.
The practical priority is therefore to control the varroa infestation and to apply the recommended varroa management concept, with authorised methods and products. It is not a matter of 'treating the virus' directly at the apiary.
Key takeaways
The typical sign of DWV is the observation of bees with deformed wings, often with a shortened abdomen or general weakness.
The problem is generally linked to Varroa destructor. A strong presence of deformed bees should lead to a quick assessment of the level of varroa infestation.
Health management relies on strong colonies, regular monitoring of varroa, appropriate comb renewal, and correct application of the varroa management concept.
Further reading
► Practical Guide: 2.8 Varroosis