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Chalk Brood

What are the signs?

When observing the hive , inspecting the entrance and bottom board/mesh you may come acroos greyish-white pellets or even dark grey to black ( when fruiting bodies are present) the size of larvae. They look like small lumps of chalk and hence the aptly named ‘Chalkbrood’. Closer inspection of the bee frames in the colony may reveal certain cells with the caps removed showing these pellets inside.

The disease is characterised by the infected brood, called ‘mummies’ so named by their appearance. Larvae die of chlakbrood after the cells have been capped.

Chalkbrood initially appears fluffy and swollen, but will shrink and become hard.

Young larvae usually die within a couple of days of having been sealed in their cells, otherwise they die as propupae.

So what is Chalkbrood?

Chalkbrood is a infectious fungal disease which is caused by Ascospaera apis and which appears to be on the increase. Only the larvae of Apis mellifera are particularly susceptible and Ascospaera apis does not multiply in adult bees and rarely kills a colony, but it will weaken a colony and reduce honey yield by up to 30%.

How is it transmitted?

Spores are highly infectious and carried in contaminated pollen by infected foraging bees with spores left at floral and water sites, drifting bees and drones. Ascospaera apis is ingested by the bee larvae with their food. Usually the spread is limited to within the colony. It is known that Ascospaera apis grows best when the brood is chilled, and the correct temperature within the brood box is an important factorin limiting infection. As the disease has a limited ability to spread, most transmission occurs through the activities of beekeepers – exchanging equipment and bees, feeding contaminated honey and using contaminated tools and gloves.

Stressing bees

Stressing bees contributes to increasing the susceptibility of Chalkbrood. Changes in brood temperature can trigger the disease. If nurse bee numbers become insufficient to cope with extreme waether conditions the brood may be left unattended. You may observe the first larvae to be affected are those around the edges of the brood where the temperature may be higher or lower. Stress of any kind can cause the Chalkbrood to become apparent.

Common causes of stress are: -

  • High and low temperatures
  • Poor nutrition
  • Poor hive management
  • Moving hives
  • Wet or dry conditions.


  • Remove chalkbrood from boards and entrance
  • Destroy infected combs
  • Ensure good ventilation
  • Feed uncontaminated supplements
  • Re-queen
  • Use clean eqipment and clean hive tools before entering the next hive
  • Treat with Bee-Vital’s -Chalkbrood


Dear Customer,
After many years of successfully helping beekeepers rid their colonies of Varroa Destructor Mites, HiveClean can no longer be sold in the UK. After lengthy discussions with the Veterinary Medicines Directorate (VMD) we have agreed not to sell or import and more HiveClean after the end of October 2016.

The reason given is quite simple and it is that another company making an oxalic acid based treatment for Varroa has paid the VMD for a registration of its product in the UK which now makes oxalic acid (and formic acid) medicinal by function and therefore any product containing these ingredients must get authorisation from the VMD to sell or use it in the UK. Unfortunately for us HiveClean contains minute amounts of both as active ingredients and therefore must now be authorised. For us, the cost to register HiveClean is so prohibitive (in the region of £30,000) that it would no longer be financially viable for BeeVital, Austria to supply the UK.

BeeBay would like to thank every one of its customers for their support and apologises if anyone has been inconvenienced by these latest events. We do assure you that we will still be serving your beekeeping needs with organic products to protect and feed your honey bees. Please watch this space.

Please also feel free to protest to the VMD about this decision, should you so wish.

Veterinary Medicines Directorate
Woodham Lane
New Haw
KT15 3LS