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| Fig. 77: The phalsa (Grewia asiatica) is primarily a beverage fruit in India. Uneven ripening requires many pickings. |
A large, scraggly shrub or small tree to 15 ft (4.5 m) or more, the phalsa has long, slender, drooping branches, the young branchlets densely coated with hairs. The alternate, deciduous, widely spaced leaves are broadly heart-shaped or ovate, pointed at the apex, oblique at the base, up to 8 in (20 cm) long and 6 1/2 in (16.25 cm) wide, and coarsely toothed, with a light, whitish bloom on the underside. Small, orange-yellow flowers are borne in dense cymes in the leaf axils. The round fruits, on 1-in (2.5 cm) peduncles are produced in great numbers in open, branched clusters. Largest fruits are 1/2 to 5/8 in (1.25-1.6 cm) wide. The skin turns from green to purplish-red and finally dark-purple or nearly black. It is covered with a thin, whitish bloom and is thin, soft and tender. The soft, fibrous flesh is greenish-white stained with purplish-red near the skin and becoming suffused with this color as it progresses to overripeness. The flavor is pleasantly acid, somewhat grapelike. Large fruits have 2 hemispherical, hard, buff-colored seeds 3/16 in (5 mm) wide. Small fruits are single-seeded.
The phalsa is indigenous throughout much of India and Southeast Asia. It is cultivated commercially mainly in the Punjab and around Bombay. It was introduced into the Philippines before 1914 and is naturalized at low elevations in dry zones of the island of Luzon. Only a few specimens have been planted in the New World, for example, at the former Federal Experiment Station, Mayaguez, Puerto Rico, and the Agricultural Research and Education Center, Homestead, Florida.
The tall-growing wild plants bear acid fruits which are not relished. The dwarf, shrubby type, with a blend of sweet-and-acid in the best fruits, is cultivated.
In India, the phalsa grows well up to an elevation of 3,000 ft (914 m). It can stand light frosts which cause only shedding of leaves.
The phalsa grows in most any soil–sand, clay or limestone–but rich loam improves fruit production, as does irrigation during the fruiting season and in dry periods, even though the tree is drought-tolerant. Generally, it is grown in marginal land close to city markets.
Seeds are the usual means of propagation and they germinate in 15 days. Ground-layers, treated with hormones, have been 50% successful; air-layers, 85%. Cuttings are difficult to root. Only 20% of semi-hardwood cuttings from spring flush, treated with 1,000 ppm NAA, and planted in July (in India) rooted and grew normally.
Seedlings are transplanted from seedbeds into well-prepared holes when a year old and are usually spaced 10 to 15 ft (3-4.5 m) apart, though some experiments have favored 6 x 6 ft (1.8 x 1.8 m) or 8 x 8 ft (2.4 x 2.4 m) to maximize efficiency in harvesting. Fruiting will commence in 13 to 15 months. Annual pruning to a height of 3 to 4 ft (0.9-1.2 m) encourages new shoots and better yields than more drastic trimming.
Sprays of 10 ppm gibberellic acid have increased fruit-set. At 40 ppm, there is increased fruit size but decreased fruit-set. In fertilizer experiments, the plant has shown good vegetative response to applications of nitrogen. High levels of phosphorus increase sugar content, while potassium decreases sugar and elevates acidity.
Summer is the fruiting season. Only a few fruits in a cluster ripen at any one time, so continuous harvesting is necessary. The fruits keep poorly and must be marketed within 24 hours. Average yield per plant is 20 to 25 lbs (9-11 kg) in a season.
Leaf-cutting caterpillars attack the foliage at night. A blackish caterpillar causes galls on the growing shoots. Termites often damage the roots. In some areas, leaf spot is caused by Cercospora grewiae.
The fruits are eaten fresh as dessert, are made into sirup, and extensively employed in the manufacture of soft drinks. The juice ferments so readily that sodium benzoate must be added as a preservative.
Analyses made long ago in the Philippines show the following values: calories, 329 per lb (724 per kg); moisture, 81.13%; protein, 1.58%; fat, 1.82%; crude fiber, 1.77%; sugar, 10.27%.
Leaves: The fresh leaves are valued as fodder.
Bark: The bark is used as a soap substitute in Burma. A mucilaginous extract of the bark is useful in clarifying sugar. Fiber extracted from the bark is made into rope.
Wood: The wood is yellow-white, fine-grained, strong and flexible. It is used for archers' bows, spear handles, shingles and poles for carrying loads on the shoulders. Stems that are pruned off serve as garden poles and for basket-making.
Medicinal Uses: The fruit is astringent and stomachic. When unripe, it alleviates inflammation and is administered in respiratory, cardiac and blood disorders, as well as in fever.
An infusion of the bark is given as a demulcent, febrifuge and treatment for diarrhea. The root bark is employed in treating rheumatism. The leaves are applied on skin eruptions and they are known to have antibiotic action.
The flowers have been found to contain grewinol, a long chain keto alcohol, tetratricontane-22-ol-13-one. The seeds contain 5% of a bright-yellow oil containing 8.3% palmitic acid, 11.0% stearic acid, 13.4% oleic acid, 64.5% linoleic acid; 2.8% unsaponifiable.