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RAMBUTAN

The rambutan is a medium sized tree producing a red or yellow fruit round to oval in shape with hairs or tubercles on its skin. The flesh or aril is translucent and sweet. Most rambutan trees propagated from seed is not true-to-type and usually sour. Male rambutan trees are also not uncommon. The rambutan has a small crop in June - July and a heavy crop in November to January. Selected clones produce thick, firm flesh which are sweet.

 Rambutan is indigenous to the Malay Archipelago and has been widely cultivated throughout the region in Thailand, South Vietnam, Indonesia, the Philippines, India and Sri Lanka. In Malaysia is rambutan cultivated in almost all part of the contry but is concentrated mainly the states of Perak, Pahang, Kedah, Kelantan, Johor dan Terengganu.

A large number of rambutan clones is available in the country but recommendations of clones for planting is made complicated by the inevitable effects of environment as some clones perform well in one environment or area but not in other areas. Clones which are recommended for general planting are R134, R156,R162,R167,R170, R191 and R193.

The rambutan is well adapted to the tropical and humid climate. A warm climate is ideal for its growth and high yield. It is suitable for most types of soil, except the waterlogged and peat areas. However, rambutan requires a lot of moisture and is not suitable in the hilly terrain. It does not perform well on sandy areas. Deep alluvial soil and those which contain high organic matter is ideal for its growth and development. These soils should be well drained. Soils which have a high water table is not favourable.

Rambutan is easily propogated by budding, approach grafting, and air-layering. Budding is the most common method of vegetative propogation.

 The recommended spacing for planting is 10m x 10m and ideal planting holes are 0.6m x 0.6m x 0.6m. After the holes are dug some organic matter with phosphate fertilizer and limestone are incorporated to mix into the planting holes before introducing the seedlings.

For the first 1-3 years a compound fertilizer consisting of nitrogen, phosphate potash and magnesium in the proportion of 15:15:6:4 is given. From the 4th year onwards the proportion is 12:12:17:2+TE

The weeds compete for sunlight, water and nutrients with the seedling and must be removed early. Circle weeding is done manually or chemically to prevent overgrowth of cover crops. Parquat, dalapan and glyphosphate are common herbicides used against weeds.

An open centre pruning system is recommended. Pruning is also done during harvesting to encourage the growth of fruiting branches for the next crop. Removal of dead, broken or diseased branches and water shoots is done regularly.

Larvae of the leaf roller, adoxophytes privatana walk, roll and feed on young leaves. It can be controlled chemically. Larvae of the fruit borer bore into the fruit. All fallen and infected fruits should be destroyed. The are three weevil pests - apogonia SPP., adoretus SPP and Hypomeces Squamosus which feed on and cut leaves. They are only active at night. This can be chemically controlled by spraying with Trichlorphon or BHC.

 The rambutan is relatively free of serious diseases. Powdery mildew (oidium nephelli) infect fruits causing them to split and drop. For control spray immature fruits with sulphur when symptoms appear. Corky stem canker (Dolobra nepheliae) is quite common in rambutan. It attacks branches and twigs causing the formation of corky tissue. There is no effective control but improving air circulation helps reduce its incidence. Sooty mould ( Meliola nephelii) is normally a secondary infection , after insect damage, often transmitted by wind. Both leaves and fruit develop a black sooty mould on the surface. The aril is normally not affected but the fruit is rendered unsightly. This can be controlled by spraying with copper oxychloride, benomyle or other fungicide.

Rambutans fruit twice a year. Trees begin flowering from March to May and August to October. Fruits mature from 15-18 weeks after flowering. The main fruiting season is from July to November and secondary fruiting season is from March to July. A variation of 4-6 weeks may occur in the periods for fruiting depending on locality and climatic conditions. The fruit bunch is harvested when a majority of the fruits has turned red or yellow.

Yield may begin at 1.2 tonnes per hectare for the first year of fruiting reaching as high as 20 tonnes per hectare for trees over ten years old. Yield normally varies from 12-16 tonnes per hectare. An average tree may produce between 5000 -6000 fruits although trees producing 10000 fruits have been observed.