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

kobus@africanhoneybee.co.za

www.africanhoneybee.co.za