Langsat, Duku
Lansium parasiticum

Family: Meliaceae

What it is like

An upright slender tree to 12-20 m high. It has sticky sap. The leaves are alternate and simple. Leaves are up to 40 cm long and made up of 5-7 large leaflets. The flowers are yellow in spikes from old wood mostly on the branches. The flowers have 5 petals which join to form a tube. The flowers have a sweet smell. The fruit is 3-5 cm across and divided into 5 segments with 1-2 large seeds. The fruit is borne in long drooping clusters. There can be 25 fruit in a cluster. The fruit is pale yellow when ripe. It develops a brown scurf on the surface as it ripens. The seeds are green and bitter and are not eaten. Langsats have thin skin, milky juice and are oval and 3.7 cm across. Dukus have thick skin, are round, do not have milky juice and are 5 cm across. They are also sweeter than Langsat.

There are 3 Lansium species. Fruit are reasonably high in folates 16μg/100.

Where it is found

A tropical plant. It suits the hot, wet tropical lowlands. It is native to Malaysia. It occurs in coastal areas and probably up to 700 m altitude in the tropics. A rich deep well drained soil is needed. It suits humid places and is not suited to places with a distinct dry season. It cannot tolerate drought. It can grow with an annual rainfall of less than 1,500 mm. It does well in part shade. It can tolerate lower temperature, rainfall and humidity than rambutan. A temperature between 25°-30°C is best. It grows between 17°N - 17°S. A pH between 5.0-6.0 is best.

Countries/locations it is found in

Asia, Australia, Bougainville, Cambodia, Central America, China, Cuba, East Timor, Fiji, Guianas, Hawaii, India, Indochina, Indonesia (country/location of origin), Laos, Malaysia (country/location of origin), Mexico, Myanmar, Pacific, Papua New Guinea, Philippines, Pohnpei, Puerto Rico, Sarawak, SE Asia, Singapore, South America, Sri Lanka, Suriname, Thailand, Timor-Leste, USA, Vietnam, West Indies

How it is used for food

Fruit is eaten fresh after they fall. They can also be candied, preserved in syrup, or made into wine. Seedless fruit can be bottled in syrup. NOTEThe stickiness of the juice of the fruit can be removed by dipping it in boiling water.

It is an important fruit in SE Asia. In Papua New Guinea, introduced to research farms and now being grown in a few places. It is a cultivated food plant.

Edible parts

Fruit

How it is grown

Trees are mostly grown by seed. Seeds remain viable for about 5 weeks if kept moist. Seeds should be washed and cleaned before planting. Seeds are planted 1 cm deep in a nursery. Germination takes 1- 3 weeks. When seedlings are 15 cm tall they are put into nursery beds for 1-2 years before being planted out in the field. Seedlings do not come into bearing for 12-20 years. They can be grown by budding. Buds should be put onto 4 year old rootstocks of the same species. Buds dry out quickly so should be inserted immediately. Propagation by grafting, marcottage and cuttings is difficult. A spacing of 8-10 m is suitable. Seedlings dry out quickly, so need to be transplanted carefully. Shade is normally provided for the first few years.

Trees are slow growing. Fruit production is seasonal. The season tends to be from December to March. Often trees have large crops every second year. Trees start to produce after 5-8 years but can take 15 years to bear fruit. Fruit will only last about 4 days at normal temperatures. They can be stored at low temperatures for several weeks.

Its other names

Local names

Ayer-ayer, Bejetlan, Bijitan, Boboa, Bonbon, Bongko, Bongkong, Buahan, Doekoe fruit, Duku-langsat, Kokosan, Laang-saat, Langsek, Lansa, Lansat, Lanseh, Lansek, Lansones, Lanzone, Lasak, Leang sat, Long gong, Longkong, Pitisan

Synonyms

Aglaia aquea (Jack) Kosterm.; Aglaia domestica (Correa) Pellegr.; Aglaia dookoo Griff.; Aglaia intricatoreticulata Kosterm.; Aglaia merrillii Elmer; Aglaia sepalina (Kosterm.) Kosterm.; Aglaia steenisii Kosterm.; Amoora racemosa Ridl.; Lachanodendron domesticum Nees; Lansium domesticum Correa; Melia parasitica Osbeck; Lansium aqueum (Jack) M. Roem.; Lansium domesticum var. aqueum Jack; Lansium domesticum var. pubescens Koord. & Valet.; Lansium domesticum var. typicum Backer; Lansium javanicum Koord. & Valet. ex Moll & Janss.; Lansium javanicum M. Roem.; Lansium parasiticum Sahni & Bennet; Lansium parasiticum var. aqueum (Jack) Sahni & Bennet; Lansium pedicellatum Kosterm.; Lansium sepalinum Kosterm.; Taeniochlaena polyneura Schellenb.;