Mangosteen

24.05.17

Mangosteen (Garcinia mangostana) is an equatorial tropical fruit native to the Malaysian peninsula, Sumatra and Borneo. The mangosteen (no relation to the mango) is sometimes known as the Queen of Tropical Fruit. The size of small apples, mangosteens have a thick, dark purple-coloured, inedible leathery skin. Inside, the fruit consists of creamy white segments that are similar in appearance to citrus fruits and have a delicate, sweet taste.

Overview

Mangosteen will grow up to 20 degrees of the equator making it an alternative crop for tropical regions of Australia, including north Queensland.

The mangosteen tree is very slow growing, reaching between six and 25 metres in height. First fruit takes between seven to 10 years to appear, although some trees never fruit.

In Australia, mangosteen is considered an exotic tropical fruit and is currently a small, niche industry. Organisations representing tropical fruit growers include Rare Fruits Australia, and the Rare Fruits Society.

Facts and figures

Mangosteen is a tropical fruit native to the Malaysian peninsula, Sumatra and Borneo
It is no relation to the mango
In Australia, it is considered an exotic tropical fruit and is currently a small, niche industry
Mangosteen trees need a true tropical climate: high even temperatures with high humidity
It is very slow growing, with first fruit appearing 7–10 years after establishment

Production status

Mangosteen is primarily grown in north Queensland (11,606 trees or 98.6% of total plantings in Australia). The remaining 163 trees were recorded in the Northern Territory. However, mangosteen is no longer considered a commercial industry in the Northern Territory, due mainly to the difficulties and costs involved of maintaining trees during the dry season. Mangosteen is rarely grown as a single enterprise crop, rather it is grown as part of a mix of tree crops.

Most mangosteens are consumed domestically, although small amounts are exported.

Mangosteen production is dependent on ideal environmental conditions, so yearly production is highly variable.

Map of current and potential growing regions

Uses

Mangosteen can be eaten like any tropical fruit, either directly from their skin, in fruit salads or desserts. Mangosteen can be canned, frozen or made into juice, preserves and syrup. In parts of Asia, mangosteen is used in traditional medicine.

Production Requirements

Growing regions

Mangosteens are grown along the wet coastal strip from Cooktown (15°S) to Tully (18°S) in Queensland. While the northern Queensland environment is suitable for mangosteen production, the cooler temperatures during July–August will limit the areas where it can be grown.

Mangosteen has been grown around Darwin, however the difficulties of managing the crop during the cooler, drier temperatures during July–August mean it is no longer considered a commercial crop in the Northern Territory.

In order to provide the optimum conditions, mangosteen should not be grown at altitudes higher than 500 metres above sea level.

Soil type

Mangosteen will grow on a wide range of soils provided it has good water holding capacity, but it will not tolerate waterlogged areas. It does best in deep, rich organic soil that is slightly acid (pH 5.0–6.0). The tree grows well on deep river loams and not so well on sandy soils with low organic matter levels.

Climate

Mangosteen prefers an equatorial climate—high even temperatures with high humidity. Its preferred temperature range is 20–33°C and it cannot tolerate temperatures below 5°C nor above 38°C. Seedlings are particularly sensitive to cold and will fail if the temperature drops below 8°C.

Mangosteen requires high atmospheric humidity and an annual rainfall of at least 1,200 millimetres with no long periods of drought. Supplementary irrigation may have to be applied in months with less than 150mm of rainfall. Although moisture-stressed trees may crop well initially, the size of the fruit will decrease and subsequent cropping will be reduced until the trees recover.

Varieties

For many years only a single variety of mangosteen, within the Garcinia mangostana species, was thought to exist due to the parthenocarpic (fruit produces without fertilisation) nature of the fruit. However, growers have long recognised at least two basic fruit types, spherical and oblong, and there are a number of colours. With the advent of genetic finger-printing, several different types have been identified in Australia. The distinctions between type are based primarily on fruit shape, with acidity and flavour remaining similar.

There are other species of Garcinia grown in Australia. A commercial planting of Garcinia hombriana (seashore mangosteen) is grown commercially south of Townsville, while a number of other species are grown by rare fruit enthusiasts, such as the yellow mangosteen (G. dulcis), Cambogia (G. cambogia), and madrano (G. braziliansis).

Planting and crop management

Mangosteen is generally propagated from seed as the plants are genetically identical to the parent tree. Grafted trees are occasionally produced, but although they are reported to be earlier bearing, the trees are small and produce smaller fruit compared to seedling trees. Grafted trees are rarely used for commercial production due to their low vigour, but are ideal for backyard production. Seedlings are available from specialist nurseries (contact growers or industry organisations for further information) and should be propagated in pots for planting at one to two years.

Deep ripping of the soil is recommended, and if the area is prone to waterlogging or ponding, mounding will be required. Manure and compost may be incorporated into the planting sites 6–9 months prior to planting.

Mangosteen seedlings should be planted at the beginning of the wet season at a minimum distance of six metres between plants in the row and 6–8 metres between rows, resulting in an initial stocking rate of 280 trees/ha.

Because it is an understorey species in tropical rainforests (meaning it grows below taller trees), the mangosteen prefers shading during early growth and development, and shelter throughout its life. Replicating the rainforest understory conditions using other tree species is successful but leads to increased management due to the shade species and increases the risk of tree damage under cyclonic conditions.

The use of shade cloth to protect the trees is recommended for the first couple of years. However, it is important not to cut out more than 50% of the light, as trees will not thrive, resulting in tall and skinny trees with poor fruiting potential. Shade must be provided immediately after planting, ensuring no foliage is exposed to full sunlight. The shade enclosure should be of an adequate size to allow the tree to grow. Alternatively the use of “sun screens” in the form of kaolinite or lime based sprays mixed with 5% white plastic paint have been used successfully.

Planting of windbreaks will be necessary to protect mangosteen trees from exposure to wind and low humidity, particularly during the dry season. Seek advice from local departments of agriculture or forestry for suitable species of tree for each region. In far north Queensland successful wind break species include Jambolin Plum (S. cumeni), Bamaga Satinash (Syzygium tierneyanum) while fruiting species such as jackfruit (Artocarpus heterophyllus) or Black Sapote (Diospyros digyna) may provide an option that not only serves as a windbreak, but also produces an exotic tropical fruit for harvest.

Pruning of growing trees should be done to achieve the desired single trunk of at least three metres in height. A general maintenance program, including mulching , irrigating and the removal of weeds is recommended.

Mangosteens are low maintenance trees and fertiliser requirements for young trees are minimal, but will increase as the trees age to ensure high yields. Mulching after the end of the wet season using straw is generally practiced to improve soil structure and moisture.

Irrigation is essential during the dry season for juvenile trees. Once trees reach fruit-bearing age irrigation can be “carefully” withheld or substantially reduced for 4 to 6 weeks during the dry season in an effort to induce flower induction. Longitudinal wrinkling of the terminal shoots suggests that sufficient soil moisture stress has occurred. Trees should be heavily irrigated and fertigated or foliar sprayed with urea to induce the release of the floral bud.

Following harvesting of fruit, pruning of low lying branches and internal secondary branches is recommended. When trees have reached the maximum preferred height the tree can be carefully topped by pruning out the top branches. Topped trees may benefit from additional sunburn protection as detailed earlier for juvenile trees. Any large cut surfaces should be treated with a wound dressing (copper/plastic paint paste or bituminous paint).

Weeds, pests, and diseases

The area under the canopy should be well mulched and weed free, to reduce competition with young plants and to maintain plantation hygiene once the trees are established.

Mangosteen is moderately susceptible to a range of pests and diseases, which are exacerbated in suboptimal environments.

Leaf eating pests (caterpillars, grasshoppers, beetles) can be a problem in young trees. Severe defoliation can slow development so they should be controlled early. Fruit skin quality can be adversely affected by a mite and red-banded thrip and while only cosmetic in nature, any damage can greatly devalue the fruit for the fresh market. Control methods include treating with spinetoram insecticide and elemental sulphur as a miticide.

In north Queensland, Pestalotia sp. has been associated with canker development and shoot tip die back. This disease is seen more commonly where trees are growing poorly or have been severely sunburned following a rapid loss of shade. Stem canker, algal leaf spot, and sooty mould can also be problems. There are a range of fungicide copper and sulphur products that can be used to treat diseases.

Please check the Pubcris Database on the Australian Pesticides and Veterinary Medicines Authority website to see if there are any chemicals either registered or permitted for your specific crop or more generally for your crop grouping e.g. mangosteen specifically or tropical fruit more generally. Once you have found the chemicals listed, view the label and follow the instructions according to the label.

Infrastructure Requirements

The existing infrastructure on most established horticultural enterprises would suit mangosteen production. This includes an irrigation system, as well as cleaning, sorting, packing and refrigeration infrastructure.

Mangosteen will require shading when young, therefore shade cloth and frames to support the shade cloth will be necessary.

Harvesting & Processing

The harvest period for mangosteen in Australia is January to March. Generally, mangosteen can be harvested 13–14 weeks after fruit set. Yields are variable but 400–900 fruit can be expected from each mature tree.

The fruit are predominately located on the outside edge of the tree’s canopy but are also found within the canopy. Fruit are handpicked once they are physiologically mature and commence a colour change from green to purple (yellow/red in colour). Fruit that is purple is over ripe and not desirable, as it will damage easily during packing and transport.

Fruit have a climacteric respiratory pattern and colour change will continue to develop after picking. Fresh fruit is best but mangosteen can be stored for up to 4 weeks under low temperature (13°C) and controlled atmosphere conditions.

At this stage, mangosteen are packed on farm and sold to consolidators, wholesalers or directly to retail outlets, where they are on sold, used in the food service industry or processed for other uses.

Markets & Marketing

Exotic tropical fruit is considered a small niche industry and the fruit is currently grown in small quantities, therefore marketing can be a challenge. When planning to market any horticultural product, it is important to remember that wholesalers and retailers are generally looking for the following attributes from a supplier:

a great tasting product
high quality flesh texture
on-time delivery and consistency of supply.

The need for on-time delivery and consistency of supply, usually at high volumes, can hamper exotic tropical fruit producers from actively participating in the larger horticultural market. This has been a particular challenge for growers in north Queensland recovering from cyclones Larry and Yasi, where a large part of the exotic tropical fruit industry was destroyed. Those growers who have decided to re-plant and are harvesting fruit from their remaining trees have noted the difficulty in supplying consistent volumes, large enough to justify transport costs or attract wholesalers. As a result, many growers are marketing at a local level, for example selling at farmers markets or directly to restaurants. Some growers are investigating tourism opportunities through farm tours or farm gate sales. Research is also underway into potential value-add opportunities for exotic tropical fruit.

Due to insufficient production data or firm market prices, the economics for mangosteen production is not established. As at 2011, yields of 5,550 kg/ha and a farm gate price of AU$8/kg were used in calculations that indicated a breakeven period of 20 years for mangosteen, with an initial investment of AU$191,100 required to establish a five hectare orchard and with recurrent costs of AU$73,333 per year.

Factors affecting the price are seasonal availability, the availability of substitute products and consumer spending and preferences. Premium produce will generally earn a premium price, however, there are no guarantees of this always happening. For example, an oversupply of high quality fruit will depress prices but equally, periods of low availability will see even average quality fruit command high prices.

Fresh mangosteen is a product with a relatively strong demand in North America and Europe. Thai mangosteens already have a strong presence in Europe from May to July and hence any new suppliers considering those markets should consider supply times that do not clash with Thai production times.

Both North America and Europe have stringent import conditions covering food safety and pesticide residues. The United States also has stringent import regulations based on pest and disease quarantine issues and fruit may have to undergo costly quarantine treatments before being granted entry. The United States Department of Agriculture (USDA) has approved the importation of irradiated fruit from Thailand, which gives that country a trade advantage over potential Australian exports.

Specialty market opportunities may exist for mangosteen depending on growing location and markets. Some Australian producers are exploring the organic market, however it is not thought to provide the price premium required to make it viable, at this stage.

It is often suggested that one of the best ways to monitor price signals and plan production accordingly is the establishment of good business relationships between the grower and the wholesaler/agent. This can add some transparency around market signals.

Risks & Regulations

Risks/challenges

Like all tree crops, the biggest commercial risk to new entrants to the industry is the length of time between planting and first harvest. Short-term returns on mangosteen are not possible because of the long period between planting and commercial harvest (7–10 years). Assuming good culture and maintenance of the crop, a complete return on investment may be possible at 15–20 years after establishment.

General risks associated with growing exotic tropical fruits are different for each market but may include:

unpredictable weather conditions affecting yield, meaning inconsistent cropping from year to year
crop losses from birds or flying foxes that may require expensive solutions
the availability and cost of labour, as exotic tropical fruits are harvested by hand
the short amount of time to transport fruit to market before it starts to deteriorate
the challenges of understanding the marketing of exotic tropical fruits with limited information available.

Tropical cyclones pose a considerable risk to primary industries in far north Queensland and the Northern Territory. Cyclones Larry (2006) and Yasi (2011) devastated production areas of far north Queensland around the towns of Innisfail, Tully and Cardwell and inland regions of the southern Atherton Tablelands.

In the aftermath of Cyclone Yasi, a number of Queensland growers left the tropical tree fruit industry. While an understanding of the lessons learned by these cyclone events has been documented, research into cyclone preparedness is still underway with a range of management options, like trellising of fruit trees, being investigated. Since the cyclones, securing affordable insurance is a major challenge to growers in cyclone prone regions with some insurers declining to offer insurance at all.

Regulatory considerations

Before buying new land to plant orchards, a thorough investigation of the land’s suitability for a horticultural enterprise and its cropping or land use history, should be undertaken. This may include identifying a history of chemical contamination (and residue levels) as some export licences may be withheld on products grown on land where chemical residues exist. Potential disease risks should also be investigated.

It is recommended that prospective growers consult their local Department of Agriculture and/or other growers to consider any soil issues, such as contamination and potential disease risk when considering site selection. Growers will also be responsible for regularly inspecting their orchards for notifiable pests and diseases and reporting any incidence to the relevant state agriculture department.

When planting new orchards and establishing additional on-farm infrastructure or access roads, liaison with state government agencies responsible for planning, native vegetation laws and water licences will be necessary. Some land use applications will also need to be considered by the relevant local government authority.

Horticulture and food production businesses have strict requirements in relation to record keeping, registrations, and accreditations as well as associated costs for e.g. quality assurance, food safety, safe use of chemicals, environmental performance and intellectual property. Websites like Freshcare may provide a starting point for understanding these requirements.