What is a shook swarm?

It is the beekeeping operation that consists of reducing a honey bee colony to the state of a shook swarm by placing it in a clean and perfectly disinfected hive (or nucleus box) containing only frames with foundation, and this without adding any brood.

Why carry out a shook swarm ? To rid the colony of the pathogen (the bacterium Paenibacillus larvae) and its highly resistant spores (contaminating elements), or to considerably reduce their pressure, by destroying all the brood in which it multiplies as well as all materials in which the spores are preserved.

In what circumstances must it be carried out ?

Every beekeeper is obliged to comply with the specific animal health control measures for American foulbrood when this disease has been diagnosed in the apiary. In particular, any weak colony must be destroyed, even if it shows only few symptoms, as well as any severely affected colony whatever its strength.

A shook swarm onto foundation must be carried out on any diseased colony provided that:

• it is only mildly affected,
• it is sufficiently populous,
• it has retained good vitality,
• the date falls between spring and early summer.

On what principles is the effectiveness of the shook swarm based ? 

• During the 2 days following the shook swarm (the time needed to build comb), the bees eliminate the vast majority of the spores they carry on their bodies by grooming themselves. These spores thus pass into their digestive tract and are eliminated with the droppings, far enough away from the hive. The sanitary fast, even if only relative (see below), promotes the elimination of spores.
• They therefore do not contaminate the new food stores, which should only be stored from a few days after the shook swarm.
• In the new hive, after reduction to the state of a shook swarm, at least 4 to 5 days pass before new larvae appear (after the construction of new cells and the resumption of egg laying by the queen), which makes it possible to obtain a sanitary break. During this period, indeed, the susceptible larvae in which the spores can germinate and the bacterium can multiply in large quantities are absent from the colony.
• Moreover, the adult bees (nurse bees) can no longer contaminate the larvae orally, since there are not yet any larvae.

What are the conditions for a successful shook swarm ?

• The colony must be strong enough to restart as a shook swarm.
• It can only be carried out in spring and up to the beginning of summer: beyond that date the bees no longer have the capacity to build comb quickly and to gather enough food stores for winter survival. In addition, the risk of robbing is fairly high in late summer.
• It must be done outside a period of heavy nectar flow: indeed, during a strong nectar flow the bees are able to draw both sides of a frame in one night in order to place their harvest there. In that case they do not have enough time to eliminate the spores present in and on their bodies and may contaminate their new food stores.
• It must be carried out during the day and by placing the new hive in the exact location of the diseased colony, so that the foragers do not, through drifting, contaminate the entire apiary.
• During the shook swarm, brood frames must above all not be added to the transferred swarm, so that for several days there are no susceptible larvae allowing the bacterium to multiply.
• Following the various operations, at least two careful inspections of all colonies (transferred or not) should be carried out one week apart in order to monitor any possible reappearance of symptoms (thorough brood examination) and the good development of the swarms.

 

What equipment is required ?  Complete hive or nucleus box (floor, brood box, crown board) and division board, clean and perfectly disinfected. As the colony is reduced to the state of a shook swarm, it is recommended to place it first in a reduced volume: a nucleus box or a hive with a division board. Frames with foundation in a quantity suited to the strength of the colony Large sheets of paper or cloths without holes, intended to be destroyed Possibly a queen cage Disposable gloves (destroyed at the end of the operations) or disinfectable gloves Usual equipment: smoker, hive tool, brush, protective gear (to be cleaned and disinfected after the shook swarm) Large sturdy bags or boxes with lids to receive contaminated material before destruction (frames, papers, cloths, debris) and the tools before cleaning and disinfection.

 

How should the shook swarm be carried out ? 

• Smoke the affected hive.
• Move it 1 or 2 m forward, with the entrance facing the former location (180° rotation).
• Place, at the site of the affected hive, a hive or nucleus box fitted with frames with foundation.
• Lay large sheets of paper or a cloth between the entrances of the two hives, fixing one end at the level of the alighting board of the hive to be repopulated in order to collect contaminated debris (and to facilitate the bees entering the hive).
• Whenever possible, isolate the queen and place her in the new hive once part of the bees have entered it, so that the rest of the colony enters it more reliably.
• Shake or brush, one by one, the frames of the affected hive onto the cloth so that the bees fall onto it. They will gradually enter the new hive.
• Burn the papers or cloth together with the contaminated debris that fell during the manipulation, as well as all brood frames and food frames from the affected hive. Thoroughly clean and disinfect its brood box, floor and crown board, as well as any equipment that may have been contaminated (brush, hive tool, smoker). Warning : take the necessary precautions to avoid any risk of burns and fire.
• Bury the burned residues in the ground.
• If burning on site is impossible, place all material to be destroyed in strong airtight bags that are not likely to tear during handling, so that no bee attracted by honey can access them. They can be taken to containers or to a waste disposal centre for incineration, or their contents will be destroyed by fire by the beekeeper in a safe manner away from the apiary.

Should feeding be provided after a shook swarm? 

“The rule” would be that transferred colonies undergo a sanitary fast of about 48 hours, so they should not be fed before that period has elapsed. This is feasible in the case of small operations or when the apiary is close to the home.
Otherwise, in the case of transferred colonies that will not be visited again for a week, feeding may be given at the time of the shook swarm, but the quantity of sugar syrup (50/50) given to the swarm is limited to 1⁄2 or 1 litre according to its population, just enough to satisfy the vital needs of the bees for a few days without allowing them to store it.

In conclusion: 

The shook swarm is a particularly simple method for controlling American foulbrood: it requires only ordinary beekeeping equipment and no medication. Despite its rudimentary appearance, it has been used successfully for several centuries. Recommended as early as 1568 by a Silesian monk (Nikol Jacob) in his Treatise on Beekeeping, its effectiveness has since been regularly observed by beekeepers who have applied it while respecting all the recommendations, and confirmed by scientists relying on laboratory analyses showing extremely low spore levels in transferred colonies.

What are the other indications for a shook swarm with a sanitary purpose ? 

Sacbrood and European foulbrood: when a large proportion of brood is affected, but the colony remains sufficiently strong, a shook swarm onto foundation with destruction of brood and food stores is necessary. The procedure is identical to that described above, but feeding may be more substantial and immediate. As in cases of American foulbrood, diseased and weak colonies will be destroyed.

Suspicion of contamination of wax and food stores by pesticides: in this case, transferring the colony onto new frames with foundation or drawn comb is intended to rid it of any toxic agent present inside the hive by placing it in an uncontaminated environment. Concrete cases carried out at the beginning of the beekeeping season have shown that this operation allows a good restart and good colony performance. Feeding can be provided as much as necessary to help the colony resume its development.

Source: FNOSAD – Fédération Nationale des Organisations Sanitaires Apicoles Départementales

Photo credits: JM Hédon, JP Couix

See also:

• Practical Guide: 2.1 American foulbrood
• Practical Guide: 2.2 European foulbrood
• Practical Guide: 2.11 Sacbrood
• On the contagion of foulbrood diseases