Honeybees are often brought into orchards and fields with one straightforward objective: pollinate the crop. The reality is considerably more complicated.
The number of colonies required, when they should arrive, where they should be placed, and how long they should remain depend on the crop, cultivar, orchard design, flowering pattern, weather, and the forage available in the surrounding landscape.
“There is no one-size-fits-all answer,” says Mike Allsopp, honeybee researcher at the Agricultural Research Council’s Plant Protection Research Institute.
Allsopp has spent decades researching honeybees, bee health, and agricultural pollination. Speaking to Farmer’s Weekly, Allsopp that much of what is regarded as best practice in commercial pollination has developed from practical experience because controlled research into pollination is exceptionally difficult.
“Results differ for every crop and for each cultivar and for every setting,” he says. Tree size, orchard density, surrounding forage, temperature, and seasonal conditions all influence pollination. Even seemingly straightforward questions, such as how many colonies are required per hectare, cannot be answered with a single figure that applies everywhere.
“Best practice is literally that: best practice and best guesstimate,” says Allsopp. That does not mean growers have to operate blindly. Research and practical experience provide useful guidelines, while monitoring both the colonies and the crop can indicate whether those guidelines are working.
Start with the crop
The first mistake is to think of pollination simply as putting bees next to flowers. Crop biology matters. Many fruit crops require cross-pollination between compatible cultivars. Honeybees transfer pollen as they move between flowers, making colony activity an important component of successful fruit production.
South African research demonstrates the potential impact. In an almond study, flowers without access to compatible polliniser pollen had an average fruit set of only 1%, compared with 10% where compatible pollen was available.
Avocado research found a substantially greater fruit set where insects, including honeybees, had access to flowers than where insects were excluded. Litchi research similarly demonstrated the importance of insect pollination, with most bagged panicles failing to set fruit while the majority of open, mainly honeybee-pollinated panicles produced fruit.
Pollination should therefore be regarded as part of crop management rather than simply a service that can be outsourced to a beekeeper.
How many hives?
There is no magic number. Recommendations vary between crops, and Allsopp cautions against treating any figure as a fixed prescription. The number of colonies required is influenced by tree size, planting density, cultivar attractiveness, competing forage, weather, and seasonal conditions.
His advice is to plan for a poor pollination year rather than an exceptionally good one.
Commercial colonies brought into a crop are effectively an insurance policy: growers need enough pollinators available when conditions are less favourable. “It’s better to have the fruit on the trees [than] not enough,” says Allsopp.
That does not mean that continuously increasing hive numbers will solve every pollination problem. Colony quality and strength are critical, and excessive concentrations of colonies can also affect how bees distribute themselves across the landscape.
The question should therefore not simply be: How many boxes are on the farm? It should be: how many strong colonies are available, and how many bees are actually working the crop?
Colony strength counts
A box containing bees does not necessarily constitute a strong pollination colony. Allsopp places considerable emphasis on the condition and strength of the colonies supplied for pollination. “It is the beekeeper’s job to ensure that sufficient honeybees are leaving the colony,” he says.
His practical rule of thumb is approximately 50 bees leaving a colony per minute under suitable spring conditions of around 20–22°C, during the day and without excessive wind. Summer crops can require higher levels of activity.
Field activity is equally important. A strong colony does not automatically mean that its foragers are working on the target crop. “It’s not the beekeeper’s job to make sure that they’re on your target crop,” says Allsopp.
That responsibility is shared with the grower, who needs to understand what is happening in the orchard or field. The distinction is important because bees make their own decisions about where to forage.
Timing is critical
Bringing colonies into an orchard too early can be counterproductive. Allsopp generally recommends introducing bees at approximately 10% blossom, although crop-specific circumstances can require a different approach.
The reason is simple: bees are highly efficient foragers and will seek the most rewarding food sources available. If the target crop is not yet flowering sufficiently, or is less attractive than surrounding vegetation, bees can establish foraging patterns elsewhere before the crop reaches peak flowering.
Research in South African apple orchards, for example, has shown how quickly bees can switch to alternative forage. Some colonies were found to collect less than 5% apple pollen among returning foragers within three days of being introduced. This makes timing particularly important in crops that are relatively unattractive to bees.
Allsopp generally recommends removing colonies at around 90% blossom rather than keeping them until the final flowers have opened. “If you have not got pollination by 90% blossom, you’re not going to get it in the last 10%,” he says.
Colonies should be moved into and out of orchards at night. Properly prepared colonies should begin normal foraging after they have been introduced.
Place hives strategically
Placing hives directly next to the crop is not necessarily the best strategy. In orchards with mature trees or trellised systems, Allsopp generally recommends positioning colonies at the long ends of the rows. Bees tend to fly down the rows, while trellises and solid blocks of trees can act as barriers that discourage them from crossing between rows.
Low-growing crops are different. Bees can fly over crops such as onions and blueberries, making hive placement less restrictive. Allsopp also advocates what he calls “happy places” for colonies. These are sunny, sheltered sites where bees are protected from wind, kept off the ground, and able to begin foraging early. Such sites should also be away from tractors, people, and pesticide applications wherever practical.
“The more you can get your bees in a sensible, happy place, the more they will get out,” he says. High ground can also be advantageous because it allows bees to disperse more easily across an orchard or field.
Colonies do not necessarily have to be placed at every row end. On larger farms, groups of colonies can be distributed around suitable sites, provided they remain within a sensible foraging distance of the crop. The aim is to make it easy for bees to leave their colonies, disperse, and find the crop.
Pollinating under nets
Nets introduce another layer of complexity. Bees can work successfully under nets, but the design of the system determines how well they perform.
The amount of space between the crop canopy and the netting is important. More space allows bees to move freely above the crop and across rows. Light penetration also matters because bees rely on visual cues for navigation.
Allsopp’s general preference is to have colonies either properly inside a closed netted system or outside it, rather than halfway in.
The disadvantage is that colonies confined under nets can lose strength rapidly. Allsopp says colonies can lose about half their strength within seven to 10 days under some conditions because available forage inside the net is insufficient to support brood production. Bees can also become lost beneath the netting.
Three strategies can be used where colonies need to remain under closed nets: provide supplementary forage, feed colonies with appropriate nectar and pollen sources, or rotate colonies in and out of the netted area to allow them to recover.
Competing forage can change the outcome
A flowering crop is not necessarily the most attractive forage available to honeybees. Bees assess the rewards offered by different flowers and can switch to more attractive sources. This is particularly important with crops such as pears and some apple and plum cultivars, where flowers may be relatively unattractive.
South African research has documented competing forage in several crops. Almond research, for example, found bees collecting pollen from Aloe as well as almond flowers. Research on avocados has identified blackjacks, saligna gums, and early-flowering citrus among plants that can compete for bees’ attention.
The question of whether growers should deliberately plant attractive ‘bee magnet’ species is therefore more complicated than it may appear. The theory is that attracting bees into the general area of a crop will increase the number of bees available to pollinate the target flowers.
Allsopp remains unconvinced. “You might get better bee activity in the area, but that doesn’t mean that you’re going to get better bee activity on your target crop,” he says. His advice is consequently to minimise attractive competing forage during the critical flowering period of relatively unattractive crops, unless there is convincing evidence that alternative forage will improve pollination.
Protect the bees from pesticides
Pesticide management is one of the most important areas where growers and beekeepers need to work together. Allsopp warns that the problem is not limited to products that are highly toxic to bees. Fungicides, nutrient sprays, and wetting agents can also create problems.
The basic principle is to spray as little as possible during pollination and, where spraying is unavoidable, to spray at night and select the most bee-friendly registered product available.
Communication is essential. The beekeeper needs to know when spraying will take place, while the grower needs to know whether the colonies are performing as expected. A breakdown in communication can result in both dead bees and inadequate pollination.
South African research has identified pesticide exposure as one of several pressures affecting pollination services, alongside habitat transformation, loss of floral resources, pests and diseases, and climate-related pressures.
Don’t forget water
Water is another apparently minor consideration that can influence colony performance. Allsopp recommends that growers ensure bees have access to water, particularly during hot conditions.
Water is required by colonies for temperature and humidity regulation and brood rearing. Providing a reliable source close to the colonies also reduces the distance bees need to travel. The principle is straightforward: time spent travelling for water is time not spent foraging on the crop.
Treat pollination as a partnership
A commercial pollination arrangement should not be an informal transaction based simply on the number of boxes delivered to a farm. Allsopp recommends detailed contracts between growers and beekeepers covering the service expected.
Growers should use registered beekeepers and should consider whether the beekeeper belongs to a recognised organisation and whether the colonies are subject to appropriate inspection or auditing. The cheapest pollination service may not be such if the colonies supplied are weak or the service fails during the critical flowering period.
“It’s too late after the fact,” says Allsopp.
Once the crop is well into its flowering period, finding replacement colonies may be impossible. The grower therefore needs confidence that the beekeeper can supply suitable colonies when they are needed.
“Peace of mind is a big part of the deal,” adds Allsopp.
Count bees, not just hives
Technology increasingly offers sophisticated ways of monitoring colonies, including electrical and infrared monitoring. Allsopp believes growers can obtain much of the information they need through careful observation. Count the bees leaving the hives under suitable weather conditions. Then count the bees working the crop. Those two measurements provide a practical indication of colony activity and field activity.
The important point is that hive numbers alone do not measure pollination success. A farm may have what appears to be an adequate number of colonies, but if the colonies are weak, the weather is unsuitable, competing forage is abundant, or the bees are not working the crop, fruit set can still suffer.
Shared responsibility
Honeybees remain central to commercial crop pollination in South Africa. Allsopp’s own research has highlighted the economic importance of managed pollination services, while current ARC research continues to address pollination concerns in crops including onion, blueberry, and macadamia. The challenge is not simply to provide more hives, it is to make the relationship between the crop and the colony work as efficiently as possible.
Growers need to understand the flowering biology of their crop, identify potential competing forage, provide suitable hive sites, manage pesticide applications, and monitor bee activity. Beekeepers need to provide strong, healthy colonies that are properly prepared for the demands of commercial pollination.
The practical knowledge Allsopp shared with Farmer’s Weekly points to a simple principle: successful pollination is not achieved by putting the maximum number of hives next to a crop. It comes from putting strong colonies in the right place at the right time, protecting them from unnecessary risks, and ensuring that the bees actually work the target flowers.
The ultimate measure is not the number of hives standing beside an orchard. It is the number of healthy bees leaving those hives, finding the target flowers, and transferring the pollen needed to produce the crop.
Pollination checklist
Before flowering
- Confirm compatible polliniser cultivars and flowering overlap;
- Assess competing forage around the crop;
- Agree on the number and strength of colonies required;
- Finalise a detailed pollination agreement;
- Plan hive placement and access;
- Agree on pesticide protocols with the beekeeper.
During flowering
- Introduce colonies at the appropriate stage of blossom, generally around 10% for many crops;
- Monitor colony activity and bee numbers on the crop;
- Ensure colonies have access to water;
- Avoid spraying while bees are actively foraging;
- Communicate immediately if colony activity appears abnormal.
After pollination
- Remove colonies at the appropriate stage, generally around 90% blossom for many deciduous fruit crops;
- Assess fruit set and bee activity;
- Record what worked and what did not;
- Use the information to refine pollination planning for the following season.
The best pollination strategy is not simply more bees. It is the right bees, in strong colonies, at the right time, in the right place, with the grower and beekeeper working together.
