1. Monthly priorities

• Protect the winter bee generation by reducing varroa pressure without delay.
• Top up food stores early enough and at regular intervals, without blocking brood production or triggering robbing.
• Sort colonies before investing further: unite what can still become winterable, and do not artificially sustain failing colonies until spring.
• Clarify the situation of nucleus colonies and queens while a decision is still possible.
• Store supers and frames properly, recycle useful old comb, and avoid unnecessary contamination of the wax.

2. September at the apiary: the guiding principle of the month

Objective To show that September is no longer a production month, but a consolidation month in which the quality of overwintering is already being determined.

In September, the apiary shifts in its logic. Colonies remain active, but the aim is no longer to extend the season: the goal is to enter autumn with coherent, sufficiently populous colonies capable of forming a good winter cluster.

The central point of the month is straightforward: protect the winter bee generation, do not delay colony health management, top up food stores in time, and sort colonies with clear eyes before investing further. A colony that is still alive is not necessarily one that should be artificially supported until spring.

Depending on altitude, weather, and late-season forage conditions, this window may be shorter or longer. The further into the month, the smaller the margin for correction.

Further reading

• Vitellogenin and the keys to the colony
• Winter survival of honey bee colonies
• Preserving the vitality of bees
• The winter bee
• Practical Guide: 4.3 Overwintering

3. Priority tasks for the month

3.1 Treat against varroa at the right time and reassess the situation after treatment

Objective Reduce varroa pressure in time to protect winter bees still being reared, then verify that the colony resumes a coherent trajectory.

What to look at
The actual condition of the colony after the honey harvest: presence of brood, known or suspected infestation level, rationale behind the chosen treatment, general condition of the bees, and resumption of laying after the intervention. In September, treating is not enough: a follow-up visit a few days later is needed to assess how the colony has responded to this second treatment.

Concrete actions
Even if the first summer treatment was carried out on a broodless colony using oxalic acid during a brood break, the second summer treatment remains necessary within the ApiService concept and must not be omitted. In practice, the second summer treatment often begins between mid-August and early September, depending on the timing of the first summer treatment, local conditions, and the chosen treatment schedule; it should ideally be completed by mid-September at the latest. The goal is to avoid unduly shortening the laying period needed for winter bees. After treatment, monitor the resumption of laying, which may be suspended for approximately two weeks with certain formic acid treatment schedules, and verify that no problematic requeening is developing.

Points to watch
Delaying this work means exposing more winter bees to varroa. An old or already weakened queen may also respond poorly to treatment: in September, it is therefore not enough to apply a method — the colony must be inspected afterwards. If the situation remains incoherent, a decision must be made quickly.

Further reading

• Practical Guide: 1.2 Overview of summer treatment methods
• Development and dynamics of bees and varroa throughout the year
• Emergency varroa treatment in autumn: with or without brood is not the only question

3.2 Complete food stores without blocking brood production

Objective Bring colonies to a sufficient level of food stores for overwintering, without triggering robbing or unnecessarily saturating the brood nest.

What to look at
The actual hive weight, the quantity of stores already present, colony size, the space still available for laying, behaviour at the apiary, and pollen stores. In September, protein stores (pollen) also matter for the quality of winter bees, particularly in nucleus colonies and young colonies. Production colonies and nucleus colonies have neither the same stores nor the same requirements.

Concrete actions
As a rough guide, a production colony should have approximately 15 to 20 kg of food stores by the end of September, corresponding to around 4 well-filled brood box frames; at higher altitudes, around 5 food frames is often the target. Regular feeding is preferable to adding all the syrup at once. If an estimated shortfall of 10 kg is identified, this corresponds to approximately 14 litres of 3:2 sugar syrup or 12 litres of inverted syrup at 72% dry matter. A concentrated syrup is more appropriate at this time of year, as it reduces the evaporation workload for the bees.

Points to watch
Feeding too late or poorly managed can tire the bees, unnecessarily prolong activity, or block laying through lack of space. Conversely, waiting too long to supplement insufficient stores quickly narrows the margin for correction. Every hive opening and every addition must also be planned with the risk of robbing in mind.

In a year with a strong forest honey flow, it is also important to assess the practical suitability of the stores. If the honey is high in melezitose—which crystallizes quickly in the combs—a colony should not rely solely on these stores for overwintering. If this risk is confirmed, it may be necessary to replace several affected frames and then supplement the stores with appropriate feed.

Further reading

• Practical Guide: 4.2 Feeding
• Protein feeding for bees: useful or overrated?
• Summer nucleus colonies with bees from the supers
• Which syrup to choose for winter feeding

3.3 Sort colonies, decide on uniting, requeening, or elimination

Objective Enter autumn with colonies that are genuinely winterable, rather than artificially prolonging units with no clear prospects.

What to look at
The actual colony strength, queen quality, regularity of laying, state of food stores, coherence of the occupied volume, and any questionable health signs. A distinction must be made between a weak colony with remaining potential, a colony too weak for overwintering, a queenless or drone-laying colony, and a diseased or suspect colony: these call for different decisions.

Concrete actions
Unite when the resulting combined unit genuinely becomes stronger and more viable for overwintering. Monitor late nucleus colonies that are still developing. Allow requeening only when a realistic window still exists. Stop investing in failing colonies, colonies with no clear trajectory, or severely weakened units. In certain well-defined situations — in particular in the presence of disease, very high varroa infestation, or when continuing to support a colony no longer makes sense — elimination may be the most appropriate decision.

Points to watch
Uniting two weak colonies does not automatically produce a strong colony. A very weak colony does not call for the same approach as a drone-laying colony or a colony that is suspect from a health perspective. In the event of any health concern, do not unite with a healthy colony; for cases where American foulbrood is suspected, follow the standard procedure and contact the bee inspector.

Further reading

• Practical Guide: 4.7.1 Uniting colonies
• Practical Guide: 4.7.2 Destroying colonies
• The drone-laying colony
• Practical Guide: 4.7 Colony assessment and selection

3.4 Monitor nucleus colonies and replace queens where this still makes sense

Objective Clarify the situation of nucleus colonies and queens in good time, while a realistic decision can still be made before overwintering.

What to look at
Queen acceptance, presence of laying, the pace at which the nucleus colony is building up, the available population, and the realistic capacity to build up adequate food stores. In September, it is not enough for a unit to be alive: it needs to have a credible trajectory.

Concrete actionsFor summer nucleus colonies, it is important to check whether the queen has been accepted and is laying. If a still viable summer nucleus colony needs to complete its organization or finish building a few remaining combs, appropriately adapted feeding may sometimes support this process, but only under continued favorable weather, with a laying queen, sufficient colony strength, and a credible prospect of successful overwintering. The main objective at this stage remains the building up of winter stores, not the stimulation of further colony expansion. In ApiService schemes, a summer nucleus colony is generally only considered a serious candidate for overwintering once it has reached about 6 frames.

September is also a favourable period for replacing old, weak, or unsatisfactory queens: acceptance is often better than during the main nectar flow. Queens can be sourced from one's own mated queens or purchased from a trusted breeder or breeding monitor. When introducing a new queen, she should ideally have been laying for at least three weeks; the colony must have adequate food, introduction is carried out in a queen introduction cage with a fondant plug, and varroa treatment should be avoided during the three weeks following introduction.

Points to watch
In September, requeening remains possible, but uncertainty must not be allowed to drag on. A young queen accepted too late, a nucleus with no genuine laying activity, or a unit no longer building up an autumn population all offer very little margin. Before any introduction, it is also essential to confirm the absence of a residual queen, queen cells, or a drone-laying colony situation.

Further reading

• Summer nucleus colonies with bees from the supers
• Renewing colonies and queens
• How to introduce queens

3.5 Store supers, render the last frames to be retired, and properly close out the post-harvest period

Objective Close out the harvest phase properly, protect equipment, recycle wax usefully, and avoid creating problems or robbing hotspots after the season.

What to look at
Supers still in place, frames to be stored or retired, any signs of wax moth, the general condition of equipment, and anything left unnecessarily exposed at the apiary or in the workshop.

Concrete actions
Remove, sort, and store supers without leaving them lying around. A simple and effective approach is to place frames or supers in the freezer for 48 hours, then stack them in a ventilated column and in the light. To prevent intrusion by insects (bees, wasps, etc.) or rodents, the top and bottom of the stack of supers should be fitted with a bee-tight screen. Examine super frames and carefully remove any pollen-containing zones or at-risk frames. The last retired frames can also be rendered at this point to recycle the wax and progressively clean up the comb cycle.

Food frames require separate management. They are best suited to temporary storage: outside the freezer, they should be reused promptly during the season and not kept for more than a few weeks. Surplus food frames from healthy colonies, stored in autumn (in the freezer), should be used the following spring — for example, for nucleus colony formation or to supplement insufficient stores — and then rendered. Food frames must be stored separately from super frames to limit wax moth damage. Frames from diseased or dead colonies, poorly built frames, or frames containing little food should be rendered without delay after the harvest. In the event of a suspected or confirmed notifiable disease, the instructions of the bee inspector must be followed. Finally, store equipment under clean, dry, and well-ventilated conditions, and note what will need to be repaired, replaced, or brought back into service later.

Points to watch
Poorly stored supers or abandoned equipment quickly give rise to wax moth infestation, contamination, or robbing. Homemade recipes, solvents, and scented or non-approved products should be avoided: wax absorbs foreign substances readily. It is better to store cleanly, in the cold if necessary, then in the light in a cool or well-ventilated environment. In September, a clean close to the post-harvest period is already part of good preparation for the following beekeeping year.

Further reading

• Practical Guide: 4.4.2 Comb storage
• Wax moth
• Maintaining beekeeping equipment
• Practical Guide: 4.4.1 Rendering frames

4. Colony health / varroa / Asian hornet

Objective Maintain a clear interpretation of the health status of the apiary at the end of the season: varroa first, then brood condition, colony strength, and any pressure from the Asian hornet.

What to look at
The balance between open and capped brood, brood activity, colony activity, the general appearance of the bees, any signs of re-infestation, drifting, or weakening, and any anomaly that cannot be explained solely by the progression of the season. Clearly patchy brood warrants careful examination.

Concrete actions
A thorough assessment of colony dynamics in September: brood normal or not, laying present or not, colony stable or not. If signs suggestive of a brood disease are observed, the situation must not be downplayed. Where American foulbrood is suspected, the standard procedure must be followed and the bee inspector called in.

Points to watch
The seasonal decline in brood should not be used as an automatic explanation for everything. A very weak colony, clearly patchy brood, abnormal larvae, or unusual behaviour all require a serious assessment of colony health. At the end of the season, diagnoses must not be invented, and suspect colonies must not be united with healthy ones.

The seasonal decline in brood should not be used as an automatic explanation for everything. A very weak colony, clearly patchy brood, abnormal larvae, or unusual behaviour call for a real health assessment. Chalkbrood, which is of fungal origin, may also become more visible in weakened colonies or in colonies whose space is poorly matched to their strength, especially in damp or chilled conditions. In such cases, the first step is to correct the situation at the apiary: reduce the space if needed, address the source of the problem, and remove a heavily affected frame if that makes sense. The question of whether to keep the queen, or even the colony, mainly arises if the problem persists, worsens, or is combined with other signs of weakness.

Asian hornet

In September, in affected regions, predation pressure from the Asian hornet may remain high in front of hives. Monitoring the hive entrance therefore remains very important. Beyond the visible captures, this pressure can also cause marked stress within the colony: bees fly out less, foraging may drop sharply, and the colony’s overall activity can become disorganized. If this situation persists, it can seriously weaken a colony at a time that is crucial for its preparation for overwintering. In cases of confirmed attacks, a meshed entrance guard may be useful; however, it should not be installed preventively, as it makes flight more difficult for the bees. Observe, photograph, report on frelonasiatique.ch; trapping as a standard measure and direct intervention on a nest are not recommended.

Further reading

• Identifying bee diseases
• Practical Guide: 2.7 Asian hornet
• Practical Guide: 2.7.1 Instructions for meshed entrance
• Asian hornet: how to identify it and what to do at the apiary
• On the spread of foulbrood

5. Stores and available resources

Objective Understanding the apiary context: what the colony already has, what it can still find outside, and what can no longer be assumed.

What to look at
The stores actually in place, the resources still available around the apiary, the presence of pollen, colony size, and the correct match between colony strength, the volume occupied, and the volume the colony can realistically overwinter in. Pollen stores deserve a genuine assessment: they play an important role in the rearing and physiological quality of winter bees, and checking them is particularly useful in young colonies.

Concrete actions
Interpret the dynamics without expecting an ideally productive end of season. Where resources genuinely exist, incoming stores are likely; where those resources have not been verified, incoming stores must not simply be assumed. In practice, this means looking beyond honey or stored syrup: the pollen wreath around the brood and the presence of sufficient pollen frames must also be read. This point matters particularly for nucleus colonies and young colonies, which have less margin if protein supply becomes limited.

Points to watch
Late-season resources vary considerably by region, aspect, and weather. They can supplement, but rarely replace on their own, a rigorous reading of actual stores. A colony that is too populous for its available resources, or conversely too weak for the volume at its disposal, will overwinter poorly even if fed.

Further reading

• Principles of bee feeding
• Winter survival of honey bee colonies
• Pollen consumption and colony development
• Practical Guide: 3.2 Dearth periods

6. In the workshop / organisation

Objective Prepare the remainder of the season with a properly managed apiary and stored equipment, rather than allowing end-of-year improvisation to accumulate.

September is also a month for organisation: update hive records, clearly identify colonies to be monitored, united, requeened, or eliminated, store supers and frames, and plan the rendering of the last retired combs while decisions are still fresh in mind.

A clean workshop and precise records prevent many mistakes in October. The goal is not to do everything, but to finish the month with an up-to-date apiary.

Further reading

• Apiary management: beekeeping management plan
• Inspections: points of attention
• Practical Guide: 4.8.1 Entrance observation
• Practical Guide: 4.8.2 Hive floor debris check

7. What not to do now

Objective Highlight the mistakes that are costly in September, when the margin for correction narrows rapidly.

• Do not postpone colony health management in the hope that the situation will resolve itself.
• Do not feed indiscriminately without assessing food stores, colony size, pollen stores, and the risk of robbing.
• Do not unite a colony that is suspect from a health perspective with a healthy colony.
• Do not artificially sustain until spring very weak colonies with no realistic prospect of overwintering.
• Do not confuse a drone-laying or queenless colony, a very weak colony, and a diseased colony: the decisions required are not the same.

8. Depending on context

Objective Avoid overgeneralisation by keeping in mind what can vary considerably from one apiary to another.

At higher altitudes, the intervention window is often shorter: feeding, sorting, and closing the season sometimes have to be done under time pressure. The persistence of late-season resources may make a certain contribution, but must not artificially delay the fundamental decisions that need to be made.

Nucleus colonies formed at the time of super removal, Asian hornet pressure, the density of neighbouring apiaries, and the local health situation can also affect September management. The sound approach remains the same: stick to the actual situation at the apiary and do not follow an abstract calendar.

 

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