The Almond Board of Australia represents the biosecurity interests of almond producers and the industry.
In 2013–14, almond production was valued at $342 million (LVP). About three-quarters of Australian almonds are exported, going to 50 countries, with Europe the largest market and India the most valuable export country.
The Australian almond industry is concentrated in Victoria, SA and NSW with almost 30,000 hectares of cultivated almond trees. The industry is undergoing enormous expansion. Production has risen from 12,000 tonnes in 2005 to 80,000 tonnes in 2015.
It is predicted that another 15,000 hectares will be planted with almond orchards over the next three years with an expected yield of 130,000 tonnes by 2025.
Pollination of almonds (Prunus dulcis) is very important. With the appropriate number of pollinators, such as managed hives, almonds can commonly receive between 90–100 per cent nut set, which form into ‘nutlets’. However, the resulting yield at harvest time is always much lower. This can be due to a range of factors, such as excess rain, poor nutrition etc. which causes the tree to abort some of the nutlets.
Almonds generally require between 30–60 per cent yield to produce a commercial crop, with 30 per cent yield being classified as below average and 60 per cent being classified as above average. It is recommended that between 6 and 7 hives per hectare are used to achieve adequate pollination.
Almonds are one of the earliest crops to flower in the spring (August). The flowers have five petals, and a single stigma surrounded by a ring of anthers. They open before the tree produces leaves. The flowers produce both nectar and pollen. While the ovary contains two ovules, only one ovule normally develops into a seed and produces a fruit. The stigmas are usually receptive as soon as the flowers open. Almonds are generally not self-fertile and pollinisers must be planted, however new self-fertile varieties are now becoming available. Pollination is a significant factor affecting crop yield.
A wide range of insects visit almond flowers to collect pollen and nectar including flies, bumble bees (not present on mainland Australia) and honey bees. Honey bees are the most important pollinators because they can be managed and introduced to a crop. Because almonds flower early in the spring, in many situations they may be the only crop flowering in an area. Although this has the advantage there are fewer flowers surrounding the crop that may draw bees away from the almonds, it also means almonds are often open in cooler conditions, which may reduce honey bee activity. Anything that can be done to site honey bee colonies in warm sheltered positions may encourage them to forage in colder conditions. Research also indicates higher fruit set rates are achieved when hives are placed in smaller placements and spread evenly across the orchard, rather than larger placements placed less often.
For many crops it is recommended hives are not introduced until about 10 per cent flowering; however, colonies can be introduced earlier to almonds when there are few competing flowers around the orchard. Even if there is competition, a few hives should be introduced at the start of flowering to ensure the early flowers are pollinated. With the relatively high fruit set required and the large numbers of flowers on the trees, fruit set often declines quickly as with increasing distance from a polliniser. Honey bees will mainly forage on a single tree and if they leave this they are most likely to move to the next tree in the same row. It used to be common for polliniser rows to be every third row; however, it is now recommended to plant them every second row.
Because of the flower shape, pollen gatherers are likely to be better pollinators than nectar foragers. Many nectar foragers collect nectar from almond flowers without touching the stigma. Pollen gathers have a greater chance of contacting the stigma, as they scramble over the anthers to collect pollen, so there is a high frequency of contact with the stigma. Managing colonies so they have a high demand for pollen may assist pollination.
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.
Almond pollination fact sheet, The Pollination Program (Rural Industries Research and Development Corporation and Horticulture Australia Limited)
Almond pollination basics, Almond Board of Australia
Honey bee best management practices for California Almonds, California Almonds
Honeybee pollination of fruit tree crops, Victorian Department of Environment and Primary Industries
Almond pollination overview, California Almonds
|Annual value of almond production 2007–14 (LVP)|
|Distribution of almond production by state and territory 2013–14 (based on LVP)|
The pollination information is an excerpt from Mark Goodwin (2012) Pollination of Crops in Australia and New Zealand. RIRDC 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 (2015), Plant Health Australia, Canberra