Introduction
A small tree, 5 - 12 m tall, with clusters of small pink flowers, which are borne on bare branches or at leaf bases. The fruits are acutely 5-angled and distinctly star-shaped when cut across, yellow to reddish golden in colour when ripe, and about 10-15 cm in length. The total cultivated area in Peninsular Malaysia is estimated to be only about 500 ha but it gives one of the highest returns per hectare.
Varieties
Seventeen clones have been registered but only clone B10 is cultivated commercially. The fruits are sweet and juicy with a pleasant tangy flavour.
Propagation
Readily propagated by bud grafting. Budded plants begin to flower
and fruit as early as 14 months after field planting
Cultivation
Carambola grows well in a wide range of soils. It requires adequate moisture throughout the year but does not tolerate waterlogging. Regular fertilizer application is necessary for fruit production. The trees are regularly pruned and trained. Branches and watershoots are bent and held parallel to the ground so as to maintain a canopy that is "flattened" to enable fruit bagging.
Pests and Diseases
Fruits are attacked by several insects including two species of fruit flies, Bactrocera carambolae and B. papayae, and two species of lepidopteran borers -- Homona sp. and Cryptophlebia sp. The flowers are commonly infested by the flower moth Diacrotricha fasciola Zeller. (Pterophoridae). Mites (Tetranychus sp.) are occassionally a problem in prolonged hot dry weather. Carambola is relatively free of any serious diseases. Occassionally however, during prolonged wet weather in conjunction with dense canopy conditions, the young stems and shoots succumb to thread blight while Cercospora leaf spot causes defiliation as well as spotting on young fruits.
Harvesting, Handling and Storage
Carambola is non-seasonal and yields 3-5 crops per year. The fruits are harvested between 40-50 days after fruit set, when they are just beginning to turn from dark green to a light yellow-green.
• The fruits are hand picked together with the surrounding paper bags, and and transported to the packing shed in baskets.
• Fruits are then unwrapped, sorted and graded by workers using rubber gloves to minimize damage to the fruits.
• Fruits are stored at 7oC for up to six weeks during transit by sea. Fruits are also airfreighted to Hong Kong.