Without bees, between R30 billion and R40 billion of agricultural production in the Western Cape wouldn’t come to fruition. “Agriculture is now responsible for more than 50% of the GDP of the Western Cape, and much of this depends on healthy honeybee populations and successful commercial pollination,” says Mike Allsopp who oversees honeybee research at the Agricultural Research Council – Plant Health & Protection (ARC-PHP). “Natural processes are no longer enough.”

This is particularly true on the West Coast where cauliflower and broccoli seed are produced on behalf of Syngenta for export to mainly Europe, the Americas and India. Between 45 and 60 growers in the Olifants and Breede River valleys perform this crucial task, which will be impossible without bees.

But simply putting hives in fields is not enough. Control, standardisation and high hive standards are necessary to achieve the required level and quality of pollination. To this end, Syngenta contracted with the ARC and Allsopp to train its West Coast seed growers on how to monitor hive and pollination activity and, if necessary, what changes to make to ensure a productive outcome.

For commercial pollination to be successful, the bees must be properly prepared. For example, a hive’s store of honey must be calibrated carefully so that the bees are hungry enough to be motivated to work in crops that they don’t naturally favour, such as blueberries, but not so hungry that they are not strong enough to work.

Allsopp advises producers who depend on honeybee pollination to follow these guidelines:

  • Growers are legally required to use registered beekeepers with a DALRRD registration number. All hives must display an identification number. It is also best practice to insist on a written agreement with your beekeeper.
  • The number of hives you need depends on crop type and cultivar. Apples, for instance, need roughly two to four hives per hectare, whereas almonds require up to 10 due to fleeting effective pollination periods. More hives are necessary when pollination conditions are suboptimal or if the main crop must compete with more attractive forage.
  • Visit the bees on the first morning after delivery to check that the hives are open and the bees active. Normal foraging usually starts the day after delivery and, under ideal circumstances, about 50 bees should leave the colony per minute. Fewer bees indicate a potential problem with colony strength. Field strength is the number of bees visiting flowers. This will vary by crop and cultivar, but two new bees arriving per tree per minute is a general starting point. Monitor colony and field strength twice weekly and contact your beekeeper immediately if you suspect a problem.
  • Hives can be brought in at around 10% of full bloom and, if necessary, a second wave at around 50%. If you bring in the bees too early, ie, before 10% of full bloom, you risk them looking for alternative forage.
  • Generally, hives are best delivered at night as bees can get agitated and heat-stressed when moved during the day. Bees may benefit from being introduced in colder weather with time to settle in before work starts.
  • With crops under open nets, bees should be outside and allowed to fly in. Keep the sides as open as possible to prevent bees being trapped. If a net must be closed, it must be fully closed, to avoid bees escaping and then not able to return. Under closed nets, bees lose half their strength in 7 to 10 days and need to be replaced every two weeks.
  • Put hives in dry, sunny areas out of the wind. The bees will get moving faster every morning if hives face the sun and don’t stand on cold soil. Bees prefer peace, hence keep hives away from vehicles and people.
  • Bees will fly up to 5km to get to their favourite forage, which can make it challenging to keep them focused on “unattractive” pear and plum blossoms. Control weeds before the bees arrive to limit distractions and delay their discovery of alternative forage by placing hives closer to the target crop. Cover crops and flowering weeds in orchards do support colony health and reproduction and when hives are inside enclosed nets, alternative forage can stimulate the queen to keep laying, which fuels the hive’s demand for pollen.
  • Always put out water for bees, especially in hot weather and inside nets. Every minute they’re flying around searching for water is a minute they’re not pollinating the orchard. Don’t expose bees to water contaminated by any form of agrochemical.
  • A wet bee is a dead bee so avoid spraying – even water – during pollination. If you must spray or irrigate, consult the beekeeper beforehand and plan to spray at night.

In addition to pollination training, Syngenta is funding a long-term study to determine the impact of exposure to agricultural pesticides, and to intensive agriculture in general, on the health of the honeybee population of the Western Cape. Carried out by the ARC and Professor Theresa Wossler of the University of Stellenbosch Department of Botany and Zoology, the study also investigates which plants, both indigenous and exotic, are crucial to supporting the health of honeybee colonies during commercial pollination.

Source: Syngenta