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Pollination management for macadamias
in South Africa
ByAfrican Honey Bee
www.africanhoneybee.co.za
in theUSA
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
TimingMacadamia 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
PesticidesOne 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 labelso select the least harmful insecticide for bees and spray late in the afternoon
or at nighto do not spray in conditions where spray might drift onto adjacent fields
supporting. foraging beeso dispose of waste chemical or used containers correctlyo 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’ noticeo 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
0713310981
www.africanhoneybee.co.za