The Australian Macadamia Society represents the biosecurity interests of macadamia producers and the industry.
In 2016–17, macadamia production was valued at $241 million (LVP), with exports worth $291 million. Annual production from approximately 750 growers on 25,000 hectares is approximately 53,000 tonnes in-shell or 16,000 tonnes of kernel.
Approximately 70 per cent of the crop is exported, principally to Europe, the United States, Japan and other Asian countries as kernel and to China in-shell. Australia is currently the world’s largest producer of macadamia kernel. South Africa and Kenya are the other major producers.
In Australia the majority of plantings are varieties of Macadamia integrifolia. Of these about 75 per cent are Hawaiian varieties with the remainder being Australian. Five new Australian-bred varieties have been released in the last few years including MCT1, a small precocious and high yielding variety that is proving very popular. Harvest commences in March and runs through to August.
Macadamias are grown along the eastern seaboard of NSW and Queensland, from Port Macquarie in the south through to the Atherton Tablelands in the north. About half of the Australian crop is produced in NSW and half in Queensland. Production is growing fastest in Bundaberg in Queensland and the Clarence Valley in NSW. New plantings are also being developed in Mackay, Maryborough and Emerald in Queensland and in the Richmond Valley in NSW.
Ownership structures are diverse and comprise a combination of family owned orchards, first time farmers, agribusiness corporates and international and joint venture investments where the scale of new plantings is increasing significantly.
Macadamia trees (Macadamia intergrifolia and M. tetraphylla) are tall evergreen trees growing to 20 m in height. The flowers are 5–10 mm long and are born on racemes with 100–150 flowers. There are about 2,500 flowers on a tree. Each flower has 20 ovules, four anthers attached to the petals, and a long stigma. It takes about a week for all the flowers on a raceme to open, with most opening over 2 days. Most cultivars are partly or completely self-incompatible so inter-planting with compatible cultivars is usually necessary. Cross pollination has been reported to increase nut weight as well as the number of nuts. Nut set in Australia and New Zealand is usually less than 1 per cent. A three-year study of macadamia pollination in Queensland, Australia found pollination to be a limiting factor.
In Australia, macadamia will start flowering in August and September. The flowers produce both pollen and nectar. The anthers dehisce several days before the flower opens and the sigma only becomes viable after the flower opens. Flowers are visited by a range of insects including honey bees. Most honey bees collect nectar in the morning and some honey bees collect pollen in the afternoon. The flowers are attractive to bees for 3 days after opening. Each flower produces relatively small amounts of nectar. The pollen gatherers are reported to be better pollinators than nectar foragers as they are more likely to contact the stigma. Since the macadamia is native to Australia, the flowers are also visited by native stingless bee and solitary bees such as Trigona sp. However, as stingless bees are only managed on a small scale, honey bees and unmanaged stingless bees are probably the most important pollinators of macadamia. It has been estimated that about 150 bee visits to a racemes are needed for full pollination in Australia.
The optimal number of bee hives per ha is 5 to 8 based on research from both in Australia and overseas. As pollen collectors are more effective pollinators than nectar foragers, colonies should be managed to promote pollen collection eg high brood to bee ratios, sugar syrup feeding and pollen trapping or stripping.
Additional fact sheets and web links about the pollination of this crop are listed below. Please be aware that some of the information was developed overseas, and environmental and seasonal variations may occur.
Maximise your macadamia crop with better pollination (Plant and Food Research NZ and Hort Innovation)
Macadamia pollination fact sheet, The Pollination Program (AgriFutures Australia and Hort Innovation)
The effect of supplementary pollination on nut set of macadamia, University of Queensland and CSIRO research paper, Annals of Botany
Successful bee management tips for during flowering pest management, Australian Macadamia Society
Bees and the pollination of macadamia, University of the Sunshine Coast
|Annual value of macadamia production 2007–17|
|Distribution of macadamia production by state and territory 2016–17 (based on LVP)|
The pollination information is an excerpt from Mark Goodwin (2012) Pollination of Crops in Australia and New Zealand. Agrifutures Australia Publication No. 12/059
The industry overview and graphs on the value of production and crop distribution are from the National Plant Biosecurity Status Report (2018), Plant Health Australia, Canberra