Pollination management for macadamias in South Africa By African Honey Bee

in the USA each year

o Many documented trial results are available that demonstrate that well managed pollination can increase yields of macadamia o Pollination can be improved by placing hives of Apis mellifera scuttelata in the macadamia orchard o Pollination can be improved by careful planning of insecticide spraying regimes to avoid times of peak pollinator activity o Pollination can be improved by increasing the number of honeybees collecting pollen Bee pollination increases macadamia yields

Macadamia orchard layout Tree and blossom density: Orchard high density (6 x 3m) 50% Orchard lower density (10 x 4m) 40% depends on tree variety, soil conditions and topography High-density crops will have a greater blossom density and as such would require a greater amount of hives to ensure best possible pollination

Weather Temperature and rainfall have a marked effect on honey bee activity Bee activity is very limited below temperatures of 13°C Activity increases up to around 19°C, above which activity tends to remain at a relatively high level Decreases in both numbers of bees visiting blossoms and the distance from the hive at which bees forage occur with a decrease in temperature Hives should therefore be exposed to sunlight for larger parts of the day

Farm access Beekeeper = bakkie access is critical Limited access = increased workload for the beekeeper, uneven placement of hives and thus inefficient pollination Ensuring the beekeeper has good access will aid in placement of hives and be mutually beneficial to the grower (increased pollination efficiency) and the beekeeper (decreased labour effort)

Density of bees Macadamia flowers are borne on long narrow racemes arising from the axils of leaves. The racemes are pendent, 10–20cm long, with 100 to 300 white flowers Each flower is perfect with both male and female parts, and is about 12mm long Approximately 50 bee visits are made per day to each raceme The individual flowers remain attractive to insects for three days and so approximately 150 visits per raceme are required to ensure adequate pollination The optimal number of bee hives per hectare of 5–8 depending on crop density

Arrangement of hives The placement of hives within an orchard is very important to maximise pollination of a crop Place hives near the central orchard area to minimise bees targeting other sources of nectar and pollen Avoid low lying, damp and windy areas Place hives within 300m of a water source

Timing Macadamia flowers on an individual raceme open over a period of 6-12 days The peak of flower opening is variable from as early as two days from the beginning of flowering to as late as six days and so flowers on some racemes open synchronously while those on other racemes open gradually For racemes opening over a long period there are more opportunities for cross-pollination The duration of attractiveness, from anthesis to withering of the perianth, is the period corresponding to visitation by insects It is the period in which cross-pollen will arrive and hence its duration will partly determine the chances of cross-pollination Anthesis results in the presentation of pollen to flower visitors As such, it is an important factor influencing the behaviour of the flower visitors Hives should therefore be placed in orchards at least 5 days before the first flowering starts

Attractiveness and nutritional value of pollen Honey bees pollinate macadamia flowers primarily whilst foraging for pollen The quality of macadamia pollen may be variable. It ranges from 16% to 22% crude protein and the amino acid iso-leucine appears in two analyses to be a major limiting nutritional factor for bees This low nutritional value for rapidly breeding bees means that hives would need to be primed to collect pollen by harvesting the incoming pollen

Availability of bees for pollination If conditions are right bees can produce some honey from macadamias If the farmer and beekeeper work well together, the relationship can be mutually beneficial Farmers should book bees for pollination well in advance e.g. 1 year in advance Farmers and beekeepers should sign a contract to avoid misunderstandings and conflict

Pesticides One of the biggest drawbacks of placing bees near any agricultural crop is the possibility of colonies or field bees being affected by pesticides Pesticides should be kept to a minimum while hives remain on the property Most poisoning occurs when pesticides are applied to flowering crops, pastures and weeds Farmers need to take the following steps to prevent or reduce bee losses: o follow the warnings on pesticide container labels o select the least harmful insecticide for bees and spray late in the afternoon or at night o do not spray in conditions where spray might drift onto adjacent fields supporting. foraging bees o dispose of waste chemical or used containers correctly o always warn nearby beekeepers of your intention to spray in time for steps to be taken to protect the bees; give at least two days’ notice o always advise nearby farmers

Opportunities for improvement Awareness: Improved awareness of the technicalities of pollination will allow management decisions to be implemented on an informed basis This awareness should be directed to everyone involved in the implementation of management decisions in the production of macadamias including the farmer, the beekeeper and their employees

Thank you For further information on macadamia pollination solutions, please contact Kobus Visser