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.

[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.

[gavin]

I wonder if Cooper's fluctuating nest temperature (if true) is an inherent property or an effect of a smaller brood nest? Chalkbrood seems to decline as colonies strengthen, perhaps the opposite to some other problems (inc Varroa).

I was reading some papers there ... you can induce near 100% chalkbrood by chilling to 18C as late open brood then maintaining a lower temperature brood nest during pupation. Also, there is a paper from Tom Seeley's group that says that bee colonies have a 'fever' post infection with spores that appears to be a response to challenge, and is effective in reducing the problem. Just a small temperature shift, but possibly useful.

A propensity to chalkbrood might even help Amm in heather areas delay build-up to match the state of the flora. In a warm, dry season it may get away faster and take advantage of the better conditions. Assuming we have wet and dry years.

[mbc]

From "The Honeybees of the British Isles", "The character(fluctuating broodnest temp.) possibly assists in survival through adverse winter and spring conditions with reduced production of heat and hence a slower depletion of food reserves.......and not to worry too much over insignificant losses(from chalk brood) which they see."
Swings and roundabouts in the great balance of life and natural selection, or an apologist for an unwelcome trait?