Annona muricata

Common name: Soursop

Other common names: Brazilian paw paw, Graviola, Prickly custard apple, Soursapi

Names in non-English languages: Philippines French India Spanish Malaysia Thailand German China

Description

Soursop is a custard apple relative bearing large fruit, probably the largest of the custard apples. Originating in humid areas of tropical America and the Caribbean, it is now introduced and cultivated in other regions including parts of Africa, India, Southeast Asia, Australia, Hawaii and the wider Pacific.

It is a small, densely leafy tree 3 to 8 m (10 to 26 ft) tall with a slender trunk and low-branching habit, forming a pyramidal or narrowly rounded crown. The bark is grey or grey-brown and smooth.

The leaves are oblong, 10 to 20 cm (4 to 8 in) long, dark glossy green on top, pale dull green underneath and remain on the tree throughout the year, though there may be some leaf-fall in areas with a long or pronounced dry season.

The flowers are bisexual, with both female and male parts. They are a three-sided pyramidal shape 3 to 5 cm (1.2 to 2 in) long, made up of three outer and three inner yellow petals slightly opening. They are borne singly on the trunk and branches during the humid months of the year and hang down on short stalks giving off a sweet, musky odour that attracts pollinating insects.

The fruit that follow are oval to heart-shaped and large, typically 15 to 40 cm (6 to 16 in) long, up to 20 cm (8 in) wide, weigh from 1 to 7 kg (2.2 to 15 lbs) and have thin green skin dotted with soft spikes. Immature fruit are dark green and firm, becoming pale green and with a musky odour when mature, which signals a readiness for harvest.

After harvesting, the fruit are stored for around four to five days, becoming soft to the touch when fully ripe. The thin skin is easily peeled away revealing soft, very juicy, fibrous white pulp embedded with many large glossy dark brown, oblong seed.

Use

The pulp can be eaten fresh out of hand, though it is more commonly pressed trough a sieve to extract the juice or it is liquefied in a blender. Care is taken to remove the large seeds before processing. In its natural state, the juice or liquefied pulp is milky-white, smooth and has a sweet-sourish, somewhat musky flavour.

Soursop pulp is used in chilled drinks and desserts, including smoothies, ice cream and sorbets. In the West Indies, the juice is extended and smoothed with milk and then spiced with grated nutmeg to make a refreshing drink. The de-seeded pulp is also torn or cut into pieces and added to fruit salads or it can be chilled or frozen for later use.

Climate

Grows naturally and produces a fair to good crop of fruit in sub-humid to humid subtropical and tropical climates, generally in frost-free areas with annual lows of 17 to 25 °C, annual highs of 26 to 35 °C, annual rainfall of 900 to 2500 mm and a dry season of 6 months or less. Soursop trees may fail to thrive in areas where the average low of the coldest month is below 10 °C (50 °F).

Growing

New plants are usually started from seed, but can also be produced using air-layering (circumposing) methods. The young plants are planted out when around 30 cm (12 in) tall, at the start of the rainy season. They develop quickly and may start to flower and fruit in their third or fourth year, depending on the growing conditions.

Growth and fruiting performance is best on rich, free-draining loam and sand soils of a moderately acid to slightly alkaline nature, generally in 5.5 to 7.5 pH range, and on sites with full to partial sun exposure. 

Although moderately drought tolerant, it has a shallow root system and benefits from mulching, especially in areas near the lower end of its rainfall range. It performs poorly on clayey, slow-draining and waterlogged soils, with poor fruit-set and low yields the usual result.

Some of the more popular varieties include ‘Bennett’ (large fruit with flavoursome pulp), ‘Whitman fibreless’ (delicious melting pulp, but a shy bearer), 'Giant' (produces exceptionally large fruit), ‘Morada’ (commercial variety from Colombia), and 'Ratu’ and ‘Sirsak' (from Southeast Asia). There is also 'Mountain', a cold tolerant, highland variety with pale yellow pulp, but the flavour is poor and it is instead mostly used as rootstock for other varieties.

Yields of up to fifty fruit per tree per year have been reported for ten-year-old trees grown under intensive cultivation, however, yields vary greatly among the different varieties and under different growing conditions, with yields from homegrown trees about half to a quarter that of trees in commercial orchards.

Problem features

It has been recorded as a having escaped cultivation and as a weed of the natural environment and agriculture. However, there does not appear to be any records of it anywhere as a serious weed or invasive species, and it is assessed as a low weed risk species for Hawaii, by the Hawaii Pacific Weed Risk Assessment project (HPWRA).

The seed are reported to be toxic and have been used traditionally as an insecticide and fish poison.

Where it will grow

References

Books

  • Adams, C. D. 1972, Flowering plants of Jamaica, University of the West Indies, Mona, Greater Kingston

  • Allen, B. M. 1967, Malayan fruits : an introduction to the cultivated species, Donald Moore Press, Singapore

  • Food and Agriculture Organization of the United Nations (FAO) 1986, Food and Fruit-bearing Forest Species, 3 : Examples from Latin America, FAO Forestry Paper no 44/3, Rome

  • Jacquat, C. & Bertossa, G. 1990, Plants from the markets of Thailand : descriptions and uses of 241 wild and cultivated plants, with 341 colour photographs, Editions Duang Kamol, Bangkok

  • Janick, J., & Paull, R. E. 2008, The encyclopedia of fruit & nuts, CABI Publishing, Wallingford, Oxfordshire

  • Jensen, M. 1999, Trees commonly cultivated in Southeast Asia : an illustrated field guide, 2nd ed., Food and Agricultural Organisation of the United Nations (FAO) Regional Office for Asia and the Pacific (RAP), Bangkok

  • Little, E. L. et al. 1964 and 1974, Common trees of Puerto Rico and the Virgin Islands (2 volumes), Forest Service, U.S. Department of Agriculture (USDA), Washington D.C.

  • Macmillan, H. F. 1943, Tropical planting and gardening : with special reference to Ceylon, 5th ed, Macmillan Publishing, London

  • Martin, F. M., et al. 1987, Perennial edible fruits of the tropics : an inventory, U.S. Dept. of Agriculture (USDA), Agricultural Research Service, U.S. Government Printing Office (G.P.O.), Washington, D.C.

  • Morton, J. F. & Dowling, C. F. 1987, Fruits of warm climates, Creative Resources Systems, Winterville, North Carolina

  • National Research Council (Board on Science and Technology for International Development) 1975, Underexploited tropical plants with promising economic value, National Academic Press, Washington D. C.

  • Norrington, L. & Campbell, C. 2001, Tropical food gardens : a guide to growing fruit, herbs and vegetables in tropical and sub-tropical climates, Bloomings Books, Hawthorn, Victoria

  • Perkins, K. D. & Payne, W. 1981, Guide to the poisonous and irritant plants of Florida, Florida Cooperative Extension Service, Gainesville, Florida

  • Perry, F. & Hay, R. 1982, A field guide to tropical and subtropical plants, Van Nostrand Reinhold Company, New York

  • Queensland Department of Primary Industries and Fisheries (QLD DPI) 2008, Queensland tropical fruit : the healthy flavours of North Queensland, Brisbane

  • Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

  • Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

  • Selvam, V. 2007, Trees and shrubs of the Maldives, Food and Agriculture Organisation (FAO) RAP publication (Maldives), Thammada Press Company Ltd., Bangkok

Articles, Journals, Reports and Working Papers

  • Percival, S. & Findley, B. 2007 (Reviewed April 2014), What's in Your Tropical Fruit?, Fact Sheet HN 0708, University of Florida IFAS Extension Service, Gainesville, Florida

  • Subhadrabandhu, S. 2001, Under-utilized tropical fruits of Thailand, Food and Agriculture Organisation of the United Nations (FAO), Regional Office for Asia and the Pacific (RAPA), Bangkok

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