Nosema – Advice Required

Synopsis: Colony has died. Evidence of dysentery (photos below). Possible Nosema. Not wanting to use acetic acid – should I destroy all the frames and boxes or use hot air gun? Details below. Grateful for advice.

A month ago this hive was looking quiet, with a few flying bees. There were also signs of dysentery (see photo below).

At the weekend I found there were no flying bees and opened the hive.

I found signs of dysentery.

 

I found the dead queen (who was 5 years old).

I found some dead bees ready to hatch out.

Nosema

Due to the presence of dysentery it is possible that the colony died of Nosema.  Nosema is a parasitic microsporidian fungal pathogen that invades the gut of the bee. There they multiply rapidly and are then excreted by the bees. Spores are picked up and swallowed by other bees.

The only way to diagnose Nosema is by identifying the spores under a microscope. I don’t have a microscope (yet).

Dysentery is also often associated with Nosema. But the dysentery I found in the hive might be as per usual levels of winter excretion. Hence, I cannot be 100% sure the colony had Nosema.

If it was Nosema the spores can last 12 months and infect new colonies of bees placed in the hive.

Conclusions

The hive could have died due to one of the following reasons, or combinations thereof:

1. Poor performing queen (as she was 5 years old)
2. Cold (due to lack of insulation)
3. Nosema (due to the signs of dysentery)

Reason 1 could have led to a weak colony and then to reasons 2 and 3.

Next Steps

Freezing frames does not destroy Nosema spores.

I have a hot air gun (heats up to 600C and does destroy the spores) but don’t want to use acetic acid as I only need to sort out one hive, don’t have the space for fumigation and don’t want to get involved with acetic acid at this stage in my beekeeping.

I am struggling to find good advice on the following options.

1. Destroy all frames and boxes? This seems over the top and expensive.
2. Destroy all the frames and use the hot air gun on the boxes? This will give near 100% piece of mind. But again looks over the top for a diagnosis of possible Nosema
3. Destroy frames which have dysentery and use the hot air gun on the tops of other frames and boxes? This is my current plan but will not eradicate all the spores
4. Hot air gun tops of all frames and boxes?

As ever – grateful for advice.

Read More

• My Colony Losses (records of my winter colony losses)
• Grieving For Bees (emotionally dealing with the loss of a colony)
• Beekeepers Anonymous (self-help group for dealing with colony losses)
• Bee Hygiene (how-to guide to help reduce colony losses)
• Hive One 2014 notes (gives more details on what led to this colony loss)