Finger lime

24.05.17

Overview

Finger limes are naturally grown along the east coast around the Queensland and New South Wales border. Finger lime fruit forms inside a cylindrical pod which hangs off dense, thorny trees. Fruit is small, spherical and akin to caviar in appearance. As a result of its strong flavour and visually pleasing appearance, there is high demand for finger lime products, particularly internationally. Finger limes are sold as an accompaniment to a variety of foods, an ingredient for drinks and for use in beauty products. Finger limes have a shelf life of 4-5 weeks which can be extended to 3-6 months if frozen. Trees are typically grown from rootstock and can be harvested 3-4 years after planting. If grown from rootstock, maximum fruit production usually occurs 6 years after planting however trees grown from seedlings may take 15 years.

The peak industry body for finger limes is the Australian Fingerlime Growers Association. The association aims to represent grower’s interests to government, researchers and other authorities. The Australian Native Food Industry Limited is also involved in representing finger lime growers in wider forums. The Australian Native Plant Society is another group that aims to promote, educate and build appreciation for Australian native species, including finger limes.

Facts and Figures

  • Finger limes are a native Australian bushfood
  • The colour of finger lime fruit varies from bright pinks, to yellow, green, dark brown and black
  • Methods of other citrus production can be broadly applied to finger limes
  • In 2011, Australian finger lime production was estimated to be 12 tonnes with a gross value of around AU$350 000
  • Fingers limes are more tolerant of pest and diseases than other citrus species

Production Status

In 2012, there were approximately 25 finger lime producers in south east Queensland and northern New South Wales. Most growers rely on harvest from cultivated plantings rather than wild sources. Average plantation size is between 100-300 trees, with many finger lime producers also producing other citrus or native foods.

Map of current and potential growing regions

Uses

Finger limes are a highly versatile fruit which can be used in a range of food and beauty products. Fruit is small, spherical and akin to caviar in appearance and has a crunchy, juicy texture. Primarily finger limes are used to compliment seafood, desserts, soups and salads. Restaurants also use finger lime pulp as a garnish or decorative piece to accompany dishes. Finger limes are also used in preserves, dressings, alcoholic drinks and any product which ordinarily uses lemons or limes.

Beauty products are a further opportunity for finger lime production. The high oil content in finger lime skins is used to create anti-aging and skin repair cosmetics, however this is less established than the food markets.

Production Requirements

Growing regions

Finger limes occur naturally along the east coast of Australia around the New South Wales and Queensland border, from the Richmond River in New South Wales to Mount Tamborine in Queensland. Commercial production is generally within this region, however some cultivation exceeds this range and may span from the South Coast of New South Wales to Bundaberg in Queensland.

Soil type

Finger limes are suited to soils which support other citrus species. Well drained soil with a pH(water) of between 5 and 6.5 are preferable, however finger limes will tolerate poor soils. Rootstock species used to establish finger lime trees may have less tolerance to poor soils.

Climate

Finger limes grow naturally in warm, sub-tropical regions and thrive with summer-autumn dominant rainfall. Trees can tolerate dry conditions and cold weather, but do best in their natural growing regions. Mature finger limes can tolerate light frost but young plants will require protection. Finger limes can tolerate full sunlight and shaded conditions. Care should be taken to protect trees from hot or cold winds because this is the primary cause of fruit damage.

Varieties

There are a number of finger lime varieties which have been developed through selective breeding of wild plants and hybridisation with other citrus species. Not all species are ideal for commercial production and shelf life is variable between species. Some cultivars are protected under Plant Breeders Rights (PBR). Care should be taken to ensure plants are purchased from a licensed nursery.

A range of finger lime cultivars can be grown commercially. Some varieties which are grown for commercial production include:

Variety Tree/shrub appearance  Finger lime fruit Commercial merit
Rainforest pearl Small upright tree Green fruit with pink flesh Good long term availability
Alstonville Tall shrub Dark green fruit with pale green flesh Highly productive
Blunobia Pink Crystal Dense medium shrub Green-brown fruit with pink flesh
Durhams Emerald Medium shrub Black fruit with green flesh
Judy’s Everbearing Dense medium tree Dark green fruit with clear flesh May produce occasional fruit throughout the year

Planting and crop management

Commercial finger lime trees are typically propagated using budwood rather than growing from seed. Trees grown from seed are slower to produce fruit, have reduced growing rate and are not always a replica of the parent species.

Finger limes are often planted in spring to avoid frost, however, can be planted in autumn in warmer regions. Many commercial growers use a hedgerow planting system although trees planted in heavy soils or high rainfall areas can be planted on mounded rows to maximise drainage.

Fruit production can be supported with light fertiliser application in spring. Fruit production usually occurs 3-4 years after planting and reaches maximum production by 6 years.

Weeds, pests and disease

Managing weeds is important for finger limes as they compete with the trees for nutrients, can be a vector for viruses (bacterial and fungal), as well as attract insects that can cause damage to the plantings and crop. Before planting, the site should be free of weeds and ongoing weed control will be required as for any other fruit crop.

Commercial finger limes are affected by the same pests that affect other citrus varieties (though to a lesser extent). Some pests which impact finger lime production include the spined citrus bug, bronze orange bug, aphids, mealybugs, caterpillars, snails, katydids and grasshoppers. Preliminary research suggests finger limes are not hosts for fruit fly.

Pests can be treated with a variety of pesticides, destruction of infested fruit and foliage or, if isolated, physical removal of the pest species. Pest Oil is a widely used pesticide which can control a range of citrus pest species.

Some diseases which are common to citrus also affect finger limes. These include dieback, Melanose, Stylar End Breakdown and Oleocellosis. Selection of resistant varieties, appropriate care at harvest time to ensure ongoing plant health and treatments such as copper fungicide are some of the strategies used to manage these diseases.

Infrastructure Requirements

Infrastructure used to produce traditional citrus varieties is largely compatible with finger lime production. Some of the equipment required includes:

  • Drip irrigation
  • Soil moisture monitoring equipment
  • Soil preparation machinery
  • Pruning equipment

Finger limes also require refrigerated storage directly following harvest.

Harvesting & Processing

Finger limes trees typically flower from June to October and fruit is harvested between December and May.   Harvesting is predominantly conducted by hand because fruit is easily damaged and trees do not lend themselves to mechanical harvesting. Climatic conditions alter the maturing rate of finger lime fruit and so harvesting occurs every 10-14 days over a 6-8 week period. Fruit is picked when it changes colour, signalling that it is ripe, as it does not ripen off the tree.

Finger limes are delicate and care must be taken to avoid damage as the fruit is handled along the supply chain. Finger limes are often packed into 1-2 kilogram plastic bags and then packed into 2 or 5 kg fibreboard boxes. However, unique packaging requirements have been developed for some cultivars and new methods are constantly being tested. Refrigerated transport is commonly used to send the fruit to market.

Finger lime fruit has a shelf life of 4-5 weeks. This can be extended by freezing either the whole fruit or fruit pulp, which can then be stored for 3-6 months. As frozen finger limes do not lose their taste or colour sales are not limited to seasonal production.

Markets And Marketing

Demand for premium grade finger limes is strong and in 2012 demand continued to exceed supply, primarily being driven by the restaurant trade.

The finger lime industry is constrained by a lack of critical mass, largely due to the lack of commercial quantities or raw material and the fluidity of supply chains.

Domestically, most produce is sold at fruit and vegetable markets in Brisbane, Sydney and Melbourne. Some fruit is also provided direct to restaurants, particularly those located close to finger lime growing regions. The majority of finger lime producers are linked to marketing groups which sell produce in bulk (such as Wild Finger Lime Citrus Caviar and Finger Limeing Good Limeburst). However some individual growers sell directly to markets, restaurants and online or value add.

International demand for finger limes is high and continues to grow. In 2009, half of finger lime production was exported to European and Asian markets. There is also strong demand for finger limes in the United States however, as at 2013 this market had not been secured. The Australian Fingerlime Growers Association is working towards opening the US market to Australian growers.

In 2004, finger lime prices were AU$25-$80 per kg at the farm gate, however, this has fallen, largely due to the growth of the industry and increased availability of fruit. In 2011 fruit farm gate prices ranged from AU$12-$55 per kg. The variation of price is dependent on the quality of fruit produced. Formalised fruit grading systems would benefit the industry.

Risks and Regulations

Finger lime

Risks/Challenges

Weather conditions can have a major impact on fruit production. For example, unusually wet conditions in 2010 caused fruit to split which resulted in high losses. Wind rub and sunburn can also damage production. A further challenge is ensuring trees are properly pollinated as fruit deformation can occur without complete pollination.

Regulatory considerations

Growers are encouraged to check export requirements with the Australian Government Department of Agriculture if considering export markets. To obtain an export permit some countries conduct orchard inspections to check a property’s disease status. These checks have associated costs for producers. Domestic quarantine restrictions also apply in some growing areas, for example Queensland’s fruit fly exclusion zones.

Image gallery

Finger Lime

Cut finger limes, displaying their fruit (image source Anfil)

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