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Healthy Brood

If the beekeeper is familiar with the look of healthy worker brood, abnormalities will be more readily recognised.


The queen lays eggs at the base of cells in the brood nest. The eggs hatch after three days and develop into tiny translucent larvae, each lying at the base of the cell in a bed of milky brood food.

After 5-6 further days of development, the larvae have increased in size to almost fill the base of their individual cells. Healthy larvae are pearly-white in colour and lie in a distinct ‘C’ shape, with the head and tail curled towards one another. The body of each larva is divided into a series of segments along its length.

Wax cappings on healthy brood vary in colour from very light to dark brown and are often described as digestive biscuit colour, and look dry and slightly convex.

Drone brood cells are 1mm wider and have a domed capping.

A good even brood pattern has few empty cells and indicates the queen is laying well. Even when a queen is old or failing and the pattern becomes more chaotic, the larvae and cappings will still look healthy, provided no disease is present.

How Foulbrood is Spread

  • Infected combs

  • Comb transferred between colonies

  • Super combs

  • Robbing and drifting

  • Beekeeping equipment e.g. hive tool

  • Beesuits and gloves that are not cleaned

  • From swarms

  • Buying/importing infected bee stocks


The term ‘foulbrood’ covers two diseases of honey bee larvae, one known as American foulbrood (AFB) and the other, European foulbrood (EFB). The names bear no relation to the geographical distribution of the diseases: both occur in the United Kingdom - the annual economic damage to the beekeeping industry is considerable.


AFB is considered the most destructive brood disease in the UK, however, EFB is the most widespread, and where it occurs it can spread rapidly and is difficult to eradicate unless prompt measures are taken

Both AFB and EFB are subject to statutory controls in the UK. All colonies in the UK are at risk of contracting foulbrood. If disease occurs, but is not detected and controlled, the infection will normally spread quickly through the apiary and into adjacent apiaries belonging to other beekeepers. If the infection is spotted at an early stage and action is taken to tackle it, no further or only limited spread should occur.

Beekeeper's Responsibilities - Good Husbandry

• Keep a close eye on the health of your bees and make sure you can recognise signs of foulbrood infection and abnormalities in brood

• Plan apiaries to minimise the effects of robbing and drifting.

• Keep strong, vigorous colonies and select hygienic strains of bees that do not suffer from disease.

• Regularly replace old comb - a minimum of one third to half of the combs per brood box each year.  Some replace all the combs in the brood chambers each year as the colony expands in the spring.

•You should be familiar with the signs and causes of the diseases that may affect your bees, the action to take if foulbrood is suspected and the measures you should take to help keep your colonies healthy and productive.

•Be careful what used equipment and bees you buy. Make sure that equipment is clean and bees are healthy before parting with your money.

• The Healthy Bees Plan has produced useful advice notes about obtaining honey bees and also the sale of honey bee nuclei.

• Old, used equipment must be thoroughly sterilised before reuse.

• Be aware of the risk of spreading infection when you visit other apiaries or when other beekeepers visit you.

• If you suspect foulbrood, you must contact the DAERA for assistance. It is good practice to inform other local beekeepers so they can quickly check for signs of disease in their own bees.

• Migratory beekeeping can spread pests and diseases over long distances.

10 Rules for Foulbrood Control

1. Make sure you are familiar with the signs and causes of foulbrood and other brood disorders. 2. Inspect your colonies at the very least every spring and autumn, specifically to check for brood disease. If you are unsure, seek expert advice.

3. Never transfer combs between colonies, or divide colonies, without first checking for signs of brood disease.

4. Never bring colonies, combs or beekeeping equipment into the apiary unless you are sure that they come from a disease-free source.

5. Never buy old combs. Always sterilise second-hand hives by thoroughly scorching them with a blow lamp before use.

6. Control robbing in the apiary. Never leave combs or honey exposed to robbing bees. Never feed honey from another source to your bees.

7. If a colony of bees dies out at any time, seal the hive to prevent the remaining stores being robbed out, pending examination of the brood combs for signs of disease.

8. If any colony appears not to be thriving and the reason why is unknown, examine the brood for signs of disease.

9. Be suspicious of stray swarms. Hive them on foundation rather than drawn comb, keep them ‘isolated’ from the rest of the apiary as the colony expands and inspect them for disease once they have become established.

10. Regularly and systematically replace old brood combs in the apiary by melting them down and replacing them with frames fitted with foundation.

How To Check For Brood Disease

During an inspection, adult bees will obscure the brood cells, shake them from the comb into the brood box. Inexperienced beekeepers often find it difficult to shake bees off brood frames. The secret lies in holding the end lugs of the frame between the thumb and index finger, lifting the frame a little way out of the box, and then jerking the frame back down a similar distance into the box. This dislodges the bees in such a way that they fall to the bottom of the box and then quickly walk or fly the short distance onto the adjacent combs

With a double brood box, examine the lower box first. Set aside the first comb in a frame hanger (unlikely to contain brood), to make space to work.

Examine sealed and unsealed brood for discoloured larvae or perforated cappings.

Look for AFB scales by holding combs so the light is over your shoulder and scanning the bottom of open cells.

Using a match-stick, open any sealed cells that look abnormal and look inside. Probe the cell to examine the consistency of the remains, if they can be drawn out in a brown mucus-like thread or 'rope', AFB is present - dispose of the match-stick in the smoker.

Examine all brood combs. Flame the hive tool before examining another hive.

For Antrim and Londonderry:

Kevin Bradley


028 7939 5331


European Foulbrood (EFB) - Notifiable Disease

  • A non-spore forming bacterial disease

  • Larvae die BEFORE cells are sealed

  • Related to stress conditions, especially protein proficiency

  • Visible in spring/early summer when there is more brood:bees

  • Spread by transferring bees and combs between colonies

  • Captured swarms should be inspected before placing in the apiary


  • Required by law to notify the DAERA Bee Inspector

  • If disease is severe, colony will be destroyed by burning, including frames

  • If disease is mild, Bee Inspector may permit a shook-swarm procedure


  • Infested larvae lie twisted in their cells

  • Larvae have a 'melted' appearance

  • Larvae turn yellowish-brown and dry to a brown scale

  • Adult bees remove the scales

  • Pepper-pot brood pattern: if cell is capped, it will be sunken and perforated 

  • A well-fed larva can survive, but cell will be soiled

  • Match-stick test will NOT have a ropey trail

Shook Swarm

  • Locate the queen and move her to the clean hive manually

  • Shake all of the other adult bees into a colony in a clean hive filled with frames of foundation, with no drawn comb

  • A disruptive process that sacrifices all the existing brood

  • Bees will rapidly make fresh comb

Sac brood

  • Caused by a Iflavirus genus virus

  • Larva does not acheive the final moult stage

  • Dead larva lie in fluid-filled sac

  • Larva dries out over time to a brown scale

  • Adult bees pull out and dispose of the dead larvae

  • Not common


Colonies usually recover naturally.

Beekeeper can help by:

  • controlling varroa mite

  • feed and improve forage

  • re-queening with a different strain


  • Fungal disease that kills larvae

  • Larval death usually occurs after cell is sealed

  • Larva dys out to a hard, chalky white lump

  • Adult bees detect a death has occurred and ubcap the cell

  • Hardened 'mummies' are usually removed and disposed of

  • Infected larvae can release millions of spores, viable for 3 years

  • Found in colonies with inadequate ventilation and in Nucs


Colonies usually recover naturally.

Beekeeper can help by:

  • improving ventilation

  • removing carcasses

  • re-queening with a different strain

Deformed Wing Virus (DWV)

  • The varroa mite is a vector for at least 5 known viruses

  • DWV is the most common

  • Wings are crumpled

  • Bees are smaller in size, with a stunted abdomen

  • Bees underweight

  • Bees only live for a few days

  • Can cause early death of pupae (spotted brood)


Treatments for Varroa, early in the autumn and with Oxalic acid in the spring, either by trickle method or vapor/fogger, keeps the varroa mite, and the associated viruses at a manageable level and gives the colony a much better chance of surviving the winter.


Nosema Apis: A single-celled organism and endemic pest that lives in the lining of the gut of the bee, reducing its ability to digest food effectively.  The organism is spread through faeces; under normal conditions, a bee will defecate away from the hive, dispersing nosema spores harmlessly.  Under stress conditions e.g. dysentry, the bee may defecate in the hive, transmitting the infection to bees on cleaning duty.  Bees crushed during inspection/manipulation can result in spread of infection when their gut contents are released.

Nosema will be present in all colonies and can be kept at unnoticeable levels by not stressing the bees unnecessarily, careful handling and by renewing old comb using Bailey frame change method. Avoid cool, damp, shady, drafty apiary sites.

  • The colony will be slow to build up

  • Adult bees are seen crawling on the ground at the hive entrance

  • Evidence of dysentry will be present on the front of the hive

Nosema Ceranae: An emergent pathogen of western honeybees and, similar to Nosema Apis, is a spore-forming intracellular parasite.  Adult bees become infected by ingesting spores. Protein absorption becomes impaired, causing poor nutrition in the bee. Considered a more virulent disease than Nosema Apis.

  • Small colony population

  • Large number of forager deaths

  • Colony slow to build up

  • Dysentry NOT usually present

  • Crawling in front of the hive NOT usually present

  • Greater chance of colony death over the winter.

Combating Nosema

  • Change comb to reduce spores, at least 1/3 of comb annually

  • Avoid cool, damp, shady, drafty apiary sites

  • Control varroa with treatments

  • Head colony with a young queen

  • Ensure adequate forage

  • Avoid stress

Acarine Mites

  • A parasitic disease of adult bees, caused by a mite

  • The mite invades the spiricals (breathing tubes), where it lives, feeds and breeds

  • Results in obstruction of the airways so that tissues become starved of oxygen

  • Reduces the worker's ability to produce enough heat to maintain cluster temperature in the winter


With a high level of Acarine infestation:

  • dead bees

  • Bees crawling in front of the hive

  • K wing (wings projecting outwards) and unable to fly

  • Distended abdomens


Grease patties - 1 part vegetable shortening to 3 parts granulated powdered sugar.

Place on the top bars in the centre

Can add spearmint oil or lemongrass


The vegetable shortening disrupts the  female mite's ability to find young bee hosts and the mite dies

1 ounce of menthol in packet form per brood box, which vaporizes and is breathed in by the bees.  Keep in the hive for 2 weeks.


  • A single-cell organism that affects the Malpighian tubules of the kidney, attacking the lining and leading to malfunction of the excretory system

  • Cysts are passed out in faeces

  • Often associated withNosema

  • Can weaken the colony

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