RAMBUTAN - HAIRY THING FROM THE FOREST

(One of a series of articles about growing fruit trees in Samoa, written by Digby Gotts and published in the 'Samoa Observer' between December 2000 and April 2001)

Any day in February in the Fugalei Market, you should start to see some golf ball size and bright red fruit covered in hairy threads. These are rambutan (lamutana in Samoan), a fruit native to Indonesia that have proven to grow very well here, preferring the hot and wet climate of the coast to the cooler climate of the hills. Rambutan translates from Indonesian as “hairy thing from the forest” and is a word I have often heard said about me as I push my way through Indonesian markets.

These fruits may look a little unusual, but once you break open the hairy shell the sweet melting flesh has few equals. It is much sweeter and a little larger than the lychee, a similar but non-hairy fruit from China unlikely to grow well in Samoa. Rambutan is best eaten fresh, but is so delicious that it is very difficult to simply eat one or two.

The trees can produce fruit in 4 years and by the time they are ten years old, can produce 400 kilograms of fruit every year. Seeds grow well, but unfortunately about half of these grow up to be male, and will never produce fruit. The female trees can produce fruit but the flesh is often strongly attached to the seed, a bit like mango, making it difficult to eat. Rambutan trees are normally grafted, producing a more compact tree with easy eating and well-flavoured fruit. The adult tree should be fed with one kilo of NPK at flowering and another at harvest, along with a monthly micronutrient spray. It will also help a second crop if the tree is sprayed with a 3% Potassium Nitrate solution just after the flowers have set fruit.

The only time rambutan trees are pruned is at the harvest, when the bunches of fruit are cut away along with a little wood. This will encourage new growth from the cut end with the possibility of a second crop that season. If the fruit are picked individually, a second crop has no chance. The timber in the branches is particularly weak and careless climbers can break off large limbs in their hunt for fruit. For this reason you should use a pole picker to harvest bunches of fruit. This can be made from a pair of secateurs with one handle attached to a bamboo pole, with a cord running from the ground through a pulley on the fixed handle, then to the other handle. Pull the cord to cut off a bunch of fruit.

For the moment, all locally grown fruit is sold in Samoa, but there is a possibility that this fruit can become an export crop. Research is presently underway to help this decision, but no definite answer will be available for 3-5 years. If this does happen, then expect the price to rise rapidly, so enjoy them while they are affordable in the markets.

Grafted trees, and more information, are available at Nafanua Horticulture Centre.

Rambutan revisited

The rambutan season is sadly drawing to a close but if you missed out on tasting these delicious morsels don’t fret too much. A second, smaller, crop is on its way and should be ready around June. This season has been the first one for growers who have cared for their trees for around 5 years. Prices at Fugalei market of $4 – 6 a kilo have made their wait worthwhile.

The MAFFM Fruit Tree Project team have had an exciting time over the past month or so sending some trial shipments of these fruits to New Zealand for market testing and to see how difficult it is to gain the approval of the NZ Quarantine service for importing this fruit. The good news is that NZ consumers enjoyed the fruit at least as much as Samoans do here, but they are willing to pay much higher prices, making the fruit a good prospect for export. The bad news is that there is still a lot of pest control work to be done in ensuring that the fruits sent to NZ are completely clean of insect pests.

MAFFM researchers have been working flat out over the harvest season testing many of the varieties of rambutan to prove to NZ Quarantine (and others) that the local fruit flies are not attracted to these fruits. This has involved breeding thousands of the flies in sealed cages and then exposing hundreds of the fruits to the flies when they are ready to lay eggs. The exposed fruit, which may have eggs inside, are then taken to another cage where they are left to allow any eggs to develop. When the larvae hatch from their egg, they leave the fruit and drop into a sawdust layer where they can be collected. Not one fruit has so far produced one larva although the trials are continuing, as there are around 8 varieties of rambutan, each of which has to be tested.

The problem pest is proving to be mealy bugs infesting the fruit. They do little damage, but there are some that are common here and not in NZ. The NZ government therefore insists that every mealy bug be removed from the fruit before they are shipped. They are easily recognised by the white hairy patches on the fruit, but not so easily removed. They are controlled on the tree by sprays of oil or soapy water, but this doesn’t remove them well enough for a quarantine standard. We have to find a safe-for-man-and-fruit cleaning process that will kill every possible mealy bug on every fruit. Work is continuing.

Another issue to be dealt with is that having identified rambutan as a strong possibility for an export crop, there are simply not yet enough trees in the country to allow an industry to become established beyond supplying the local market. Rambutan grow to be big trees and need a lot of land if they are to be grown commercially. Twenty trees, needing 2000 square meters, would be a minimum number to allow a reasonable return to a household using it’s own labour. An operation employing labour would need around 200 trees for a worthwhile return on the investment.