brood larvae dropping to varroa floor

[peesbees]

Hello,
We are first year beekeepers so not sure if this is something to worry about or not.
We have a colony where we have recently noticed what look like mummified brood larvae on the varroa floor. We have seen a few of these amongst the varroa floor debris in other colonies, but there are a lot more in this particular hive - we counted at least 50 after ten days, then this week, another 40 in 4 days.
This hive has a new queen from a swarm cell in July. The bees seem quite happy, have taken plenty food, and are still quite active bringing in a lot of pollen at the moment.
Does it happen that the queen might be laying too much for the time of year and the workers are regulating this by throwing out brood? Or could there be a more sinister reason?
We are reluctant to go into the hive to look if it is not necessary, so any advice would be appreciated.
Thanks.

[Jon]

What you are describing is a fungal disease known as chalkbrood.
It can be trivial or serious depending how much of the brood gets infected.
It tends to get worse when conditions are damp or when brood gets somewhat chilled.
There is also a strong genetic component so if it persists it is better to change the queen.
Not much you can do at this time of year other than make sure your hive is well insulated and also has adequate ventilation to alleviate dampness.

[gavin]

As always, Jon gives good advice.

I wouldn't worry. Chalkbrood is very common and even if you have a lot in a colony it doesn't affect the strength that much. If you were seeing a high proportion of brood affected in early summer then replacing the queen would be sensible.

As you have a young queen in that colony you might be seeing more simply because young queens raise brood late in the season compared to older ones.

[Adam]

Hi and welcome to the forum.

You have good ventillation as you have an OMF - assuming the slider is out - which is good. What's the site like you have the colony on? As Jon has alluded to, I think dampness is not helpful. A dry sunny winter site helps here compared to having the hive in a shady bog. If the hive is close to the ground and grass is growing up under it, then you can clear out the grass and raise the hive a little, maybe?
If the bees have food, there's not much you can do within the hive - they should be OK.

[peesbees]

Thanks for the advice Jon and Gavin. We will try not to worry too much and keep an eye out for chalk brood next year.
Adam - our site is very sheltered and it gets the sun in the morning. But it is quite close to mature trees so there can be a damp atmosphere if there is a lot of rain. The hive is on slabs so no grass coming up. The hive in question is a WBC and we have the OMF insert in at the moment but we were not sure about in for insulation or out for ventilation. I know some people here put solid floors on the winter. Maybe we will have a rethink though and do more for ventilation if that will help combat the chalk brood.