Chalk brood

[snimmo243]

One of my two colonies (bought as nucs last summer) had really bad chalk brood so I treat it with thymol last learning as I felt it was at a level that would hamper winter preparations. This seemed to help and they got through the winter fine and started building up well too, however at the last inspection the chalk brood was back with a vengeance. I think this queen is for the chop!
Interestingly/coincidently/completely unrelated (delete as appropriate) this colony has had a very low varroa count, consistently zero natural fall!

Sent from my C5303 using Tapatalk

[Jon]

Too much chalk brood is a pita. Changing the queen is the best option although it does get noticeably worse when the weather is poor and brood can get chilled.

[gavin]

Interestingly/coincidently/completely unrelated (delete as appropriate) this colony has had a very low varroa count, consistently zero natural fall!

I'd go for Interestingly. Noticed that before in non-treated survivors belonging to John McLean of W Stirlingshire. The chalky ones seemed more resistant. Was it just that that they lacked vigour, or was the chalkbrood somehow hitting infested cells? Or was it all imagination?

[Rosie]

I have heard it claimed that chalk brood is a result of a strain that keeps its nest slightly cooler than others. If true perhaps varroa like a warm nest too.

[Silvbee]

I've noticed the exact same thing with one of my colonies. Although I've also found the CB is worst in older, darker brood frames so I'll be carrying out a larger than normal frame change over this year.

[mbc]

I have heard it claimed that chalk brood is a result of a strain that keeps its nest slightly cooler than others. If true perhaps varroa like a warm nest too.

Cooper lists "FLUCTUATING BROODNEST TEMPERATURE" as one of his 23 behavioral characters of native bees in "The Honeybees of the British Isles", and quotes Italian colonies as maintaining a "remarkably constant 95 degees F"(35°C) compared to native strains under similar conditions ranging from 95 degrees F down to 65 degrees F (18°C) in the early morning after a clear-sky night. Unfortunately there are no references as to where, when or by whom this work was done and we are expected to take his word for it. He goes on to say "Breeders should learn to accept low to moderate attacks of chalk brood as indicative of their bees' possession of this habit" !!
I've just started reading this book and while finding it a good read I think I might take any recommendations with a pinch of salt.

[Jon]

while finding it a good read I think I might take any recommendations with a pinch of salt.

Very wise move MBC.
A lot of the AMM core beliefs such as AMM living longer than other races can only be found in 'Honeybees of the British Isles' and no other source.
His books are just his observations and his claims are not based on experimental work.
A good read but contains a lot of fiction.

[Rosie]

his claims are not based on experimental work.
A good read but contains a lot of fiction.

Are sure about that Jon? He was an entomologist after all and he claims to have marked young bees to test their longevity.

[snimmo243]

I suppose the question is at what stage chalk brood becomes a problem and threat to colony growth? I am also in the process of working the old frames out of the hive

Sent from my C5303 using Tapatalk

[mbc]

Any chalk brood obviously peggs back colony growth, they invest time and energy into growing larvae only to have to spend more time and energy throwing them out and cleaning the cell.