Chalkbrood is a mycosis (a disease caused by a fungus), which affects bee brood.
It is an infectious disease of the larvae, and is caused by a fungus called “Ascosphaera apis”. It looks like pieces of chalk in the comb and is chalky-white initially, but some become dark blue-grey or almost black as in the picture to the right.
The disease mostly occurs in the spring and worsens in the summer, generally disappearing in the autumn when the queen slows down laying. It causes the death and mummification of sealed brood (see the picture to the left) and seriously weakens the colony, affecting honey output and the general health and well-being of your bees. Fortunately, it only very rarely kills a colony.
The larvae in the comb ingest the spores of the fungus with their food, allowing the fungus to get into the intestine of the larvae. The young infected larvae do not usually show signs of disease, but they usually die within two days of being sealed in their cells or die as prepupae. The spread of chalkbrood within the colony is very limited, and the fungus only seems to thrive on honeybee larvae and does not appear to affect the adult bees.
Pieces of Chalkbrood
The fungus grows best when the brood is chilled, so keeping a constant temperature within the hive is a major factor that can help to keep infection at bay. The spread is usually due to the accumulation of mummies (the white chalky remnants of infected bee larvae) and the bees being unable to remove the dead bodies from the hive fast enough.
It is mostly spread between colonies through the activity of the beekeeper, on clothing and tools – another reason why good sanitary practise and careful beekeeping husbandry is essential. The spores can remain dormant for more than 3 years anywhere in the colony, including the wax foundation and frames, this means that the disease can return in previously infected colonies.
Chalkbrood is not just a problem in the UK, but is present on nearly all continents. The only place chalkbrood is not a problem is in Antarctica, and that’s only because there are no bees there! Some beekeepers are lucky enough that their colonies never suffer from chalkbrood, but it can be a harsh and serious problem if one of your colonies does!!
( Article under review )
Signs in the colony
Adult bees will tear down the cappings of the dead larvae to reveal the chalky white mummies. These lie along the length of the cell and often take on the hexagonal pattern.
The bees remove the mummies from the hive and they can often be seen on the hive floor and outside the hive.
The mummies are usually found scattered throughout the brood nest and can reach high numbers.
’Mummies’ on hive floor
The disease often appears in a peak in the late spring/early summer as the colony expands and the brood outnumber the bees. This is because there are insufficient bees to maintain the temperature and control the ventilation (CO2 build-up).
Care needs to be taken to differentiate chalk brood from mouldy pollen but this is usually concentrated around the periphery of the brood nest and tends to be a different colour.
This is done by the typical appearance of the larvae
Chalk brood spores are sticky and will attach to the comb and bees as they remove the infected larvae.
They are also readily transmitted by robbing/drifting bees. The beekeeper can also spread the disease on hive tools and comb transfer.
The disease is considered to be endemic in Britain but levels of infection will vary from colony to colony. The beekeeper has to aim to keep the infection level down.
There are no fungicides available for the larvae and spores on the bees and combs are unreachable.
Combs can be fumigated with acetic acid but heavily affected comb should be destroyed.
Viable spores will still be present on the bees and may be present in honey stores.
In severe cases re-queening from a disease free colony is recommended.
Because of the temperature/ventilation aspect of the disease it is more likely to occur in small colonies or nuclei. Ensuring that there are sufficient bees will reduce the risk.
Some strains of bee are more resistant and queens from these should be selected as part of an integrated breeding policy
Cause: Ascosphaera apis, a fungus. Effect: Chalkbrood disease affects only the brood. The diseased larvae are usually found on the outer edges of the brood nest. Workers, drones, and queens are all susceptible to the disease. Symptoms: The affected larvae are usually found on the outer fringes of the brood area. Brood cells can either be sealed or unsealed. Diseased larvae are stretched out in their cells in an upright condition. Typically, larvae dead from chalkbrood disease are chalk white, hence the name chalkbrood. Sometimes the diseased larvae can be mottled with brown or black spots, especially on the ventral sides. The color variation is from the brown to black color of the fruiting bodies (spore cysts). Transmission: The spores of Ascosphaera apis are ingested with the brood food provided by the nurse bees. The germination of the spores and proliferation of the fungus covers the larva with a white mycelium. Spores of Ascosphaera apis remain viable for years. Consequently, the infection source could be present in the cells used to rear brood. Chalkbrood appears to be most prevalent in the spring when the brood area is increasing. Chalkbrood normally does not destroy a colony. However, it can prevent normal population build-up when the disease is serious. No treatment is presently available for the control of chalkbrood. The disease usually disappears or is reduced as the air temperature increases in the summer.
Apitoxin, or honey bee venom, is a bitter colourless liquid. The active portion of the venom is a complex mixture of proteins, which causes local inflammation and acts as an anticoagulant. The venom is produced in the abdomen of worker bees from a mixture of acidic and basic secretions.
Apitoxin is acidic (pH 4.5 to 5.5). A honeybee can inject 0.1 mg of venom via its stinger. Apitoxin is similar to nettle toxin.
It is estimated that 1% of the population is allergic to bee stings. it is un confirmed that Apitoxin can be deactivated with ethanol.
Bee venom therapy is used by some as a treatment for rheumatism and joint diseases due to its anticoagulant and anti-inflammatory properties. It is also used to desensitise people allergic to insect stings.
Bee venom therapy can also be delivered in the form of Bee Venom Balm although this may be less potent than using live bee stings.
Bees leave stingers behind. Get them out as soon as possible anyway you can.
Bee Stings can often cause anaphylaxis (Shock) in people allergic to bee venom. Treatment of hornet and wasp stings is the same as for bees, except that hornets and wasps don’t leave their stingers behind and each insect can sting multiple times.
React quickly in case of anaphylaxis (Shock)
1. Get away from the bee. Bees release a scent when in danger to attract other bees. If you’re still around when reinforcements get there, they’ll sting you.
2. Remove any stingers immediately! No need to scrape off bee stingers, just remove them. It’s OK to pull stingers out with your fingers, brush them off or get them out any way you can.
The longer bee stingers are allowed to remain in the body, the more severe the reaction will be.
3. If the victim is allergic to bees, check to see if the victim is carrying an epinephrine auto-injector (EpiPen). If so, help the victim use the EpiPen. If the victim is supposed to carry an EpiPen and does not have it, call for medical help immediately! Do not wait for symptoms to appear.
Watch any victim closely for signs of anaphylaxis.
•Hives (Raised Welts)
•Shortness of Breath
If there is any concern that the victim may be developing anaphylaxis, call for emergency help immediately.
Antihistamines, such as diphenhydramine (Benedryl), can slow an anaphylactic reaction, but will not stop it.
4. Non-allergic victims will almost always develop local reactions to bee stings. Redness, swelling, and pain are all common at the site of the bee sting. The pain will usually go away pretty quickly, but swelling may last for more than a day. Use an ice pack to reduce swelling at the site.
It’s common to develop some itching at the bee sting site.
Antihistamines or calamine lotion should help.
5. Take the victim to the Hospital if stung more than 10 times, or if there are bee stings inside the nose, mouth, or throat.
Swelling from these stings can cause shortness of breath, even in non-allergic victims.
6. Use ibuprofen or acetaminophen for minor pain relief. For tenderness at the site, try a bee-sting swab to dull the pain.
You can also use an ice pack to help with swelling. Put a cloth towel between the ice and the skin and do not let the ice stay on the skin for longer than 20 minutes.
Letting ice sit directly on the skin or keeping ice on too long could result in frostbite from the ice pack.
Conventional wisdom says to scrape bee stingers away from the skin because pinching the venom sack could push extra venom into the victim. In fact, how fast you get the stinger out is much more important than how.
Honey bees leave a stinger behind when they sting a victim. Wasps, yellow jackets, and hornets do not leave a stinger. These relatives of the honey bee can also cause an anaphylactic reaction.
LIFE CYCLE OF THE HONEY BEE.
The Honey bee exists as an egg for the first three days of its life. About the third day the egg hatches to form small larvae. The larvae will exist until the 7th to 8th day. The worker bees then start to feed the larvae and the larvae continues to eat getting larger every day. The larvae become large and robust and are pearly white colour, covering the bottom of the cell. The adult bees then begin to cap the cell. The VARROA MITE must enter the cell before the cell is capped. If a varroa mite has not entered the cell before it is capped it will look for another open cell.
Once the cell is capped the larvae will continue its development within the first 24hours from larvae to pre pupae. During this transformation the honey bee larvae spin a cocoon sheds its larvae skin and becomes a pre-pupa. Day 12, during the next 24 hours the pupae will enter the white eyed pupae stage, about day 13 the pupae enters the pink eyed stage and 14th day the purple eyed pupae stage. The pigmentation of the pupae cuticle then changes as it gradually tans around the mouth and antennae sockets.
Day 16 the pupae are of a tanned colour with movement beginning to happen in the legs.
Day 18 the pupae have turned to a black headed bee stage, and finally about 20 days the honey bee chews of the capping to vacate the cell.
It is at this stage if there is Varroa mite in the cell that they will also escape with and on the honey bee.
LIFE CYCLE OF THE VARROA MITE.
The varroa mite will enter the brood cell 15-20 hours before the cell is capped. The mite will crawl down between the larvae and the cell wall and embed itself in the brood food. The varroa mite will turn itself upside down and breathe through a tube while it is in the food. As soon as the larvae has eaten all of the brood food, it frees the mite allowing the varroa mite to take its first blood feed from the pre-pupae bee. Usually this takes place around the tenth day of the honey bees development and it is about this time that the varroa mite lays its first egg. The first egg laid by the varroa mite is male, and she continues to lay at 30 hour intervals the remaining eggs being female. Varroa mite defecates frequently in the cells the faeces having a whitish appearance.
The first male varroa egg will hatch about day 12. After 48 hours, these become eight-legged protonymphs which, after feeding on the bee larva, moult into a deutonymph. Three days later, the last moult to an adult occurs. Approximately twenty-four hours later the mites mate inside the capped honey bee brood cell. The males die after copulation in the brood cell and the female mites emerge to begin the cycle again. When the adult bee chews the cap off to emerge the adult mother mite and any of her mature daughters leave the cell. Fortunately, the survival rate of the progeny is just over one per cell, the rest dying within the cell.
As the female mite lays her eggs at 30 hour intervals it is thought that the mite prefers the longer developmental cycle of the drone of 24 days over the worker of 21 days.