Chalk brood. Should I worry?

[REDWOOD]

Chalkbrood isn't caused by small colonies, it's a fungal infection exacerbated by cold and damp.

Some colonies are more susceptible to it than others and it can often be resolved by requeening.

I'm glad someone got it right

 

[BeeJayBee]

Chalkbrood can, and will, develop in large colonies in a damp location.

Small colonies will not always show signs of chalkbrood.

Not being smart here, but can you define a damp location? Are you talking about wet weather or is there more to it?

There is more to it than just wet weather. It's mostly the location of the apiary, or even individual hives within an apiary, and what happens to the rain that falls on or near the apiary.

The worst chalkbrood I've seen was in a brood and a half National colony on heavy clay soil about ten foot from a stream. The whole apiary was under trees and didn't get any direct sunlight at any point during the summer. The ground was also lower than surrounding land, so would act as a bit of a frost pocket (cold air sinks and moves to low ground). The hives were there because that's where the landowner had told the beekeeper to put them. The hives were also on low stands - just a single brick high - so were very close to the damp ground. Long grass close the the hive entrances probably didn't help much either.

Taller hive stands don't just help reduce the incidence of beekeepers back because, coupled with an open OMF, they also make sure the colony is above a layer of moving air. Stale or static air can often be damp, especially in the winter. Damp air tends to contain more CO2 and, as mBK, says CO2 can trigger germination of the chalkbrood spores (http://www.ibrabee.org.uk/component...res-of-the-chalkbrood-fungus-ascosphaera-apis)

Standing a hive on a paving slab, or anything that will raise it slightly above soil level, can help because it keeps the grass down and it raises the hive just a bit more above the ground. Black weed membrane slightly increases solar gain, so can slightly increase the temperature around a hive as well as keeping the grass down. Warm air rises, and carries moisture with it.

There's a fairly decent piece written by Roger Patterson on Dave Cushman's site. The only thing I would disagree with is to open the feeder holes - they should only be open when the bees need feeding! http://www.dave-cushman.net/bee/chalkbrood.html

Some 'old' beekeepers locally reckon that pouring a line of salt along the top bars will cure chalkbrood. I don't know if it does and I don't plan to try it, but salt will attract moisture so maybe that's why they think it works?