Fig. 43: Tahiti, or Persian lime (Citrus latifolia) (left); and the Mexican, or West Indian (C. aurantifolia) which is especially aromatic.
The Tahiti lime tree is moderately vigorous, medium to large, up to 15 or 20 ft (4.5-6 m), with nearly thornless, widespread, drooping branches. The leaves are broad-lanceolate, with winged petioles; young shoots are purplish. Flowers, borne off and on during the year but mainly in January, are slightly purple-tinged. The fruit is oval, obovate, oblong or short-elliptical, usually rounded at the base, occasionally ribbed or with a short neck; the apex is rounded with a brief nipple; 1 1/2 to 2 1/2 in (4-6.25 cm) wide, 2 to 3 in (5-7.5 cm) high; peel is vivid green until ripe when it becomes pale-yellow; smooth, thin, tightly clinging; pulp is light greenish-yellow when ripe, in 10 segments, tender, acid, but without the distinctive bouquet of the Mexican lime; usually seedless, rarely with one or a few seeds, especially if planted among a number of other Citrus species. The Tahiti lime flowers have no viable pollen.
Origin and Distribution
The origin of the Tahiti lime is unknown. It is presumed to be a hybrid of the Mexican lime and citron, or, less likely, the lemon, and it is genetically a triploid though only the normal 18 chromosomes have been reported. Dr. Groff, in a reference to Citrus aurantifolia in his "Culture and Varieties of Siamese Pummelos . . . ", said: ". . .it is represented by a large variety known as Manow klom and by a small one known as Manow yai." One might speculate as to whether the large variety might be the female parent of the Tahiti lime. At any rate, it is believed that the Tahiti was introduced into the Mediterranean region by way of Iran (formerly called Persia). It is said that, for some centuries, a virtually identical lime called 'Sakhesli' has been cultivated on the island of Djerba off the coast of Tunisia, and that the local name means "from Sakhos", an old Arabic name for Chios, a Grecian island. Portuguese traders probably carried it to Brazil, and it was apparently taken to Australia from Brazil about 1824. It reached California from Tahiti between 1850 and 1880 and had arrived in Florida by 1883. It was being grown at Lake Placid in 1897. This lime was adopted into cultivation in California but is not extensively grown there, the bulk of California's lime crop being mainly the Mexican lime. In Florida, the Tahiti quickly took the place of the more sensitive small lime and the lemon. Following World War I, the Tahiti lime became a well-established commercial crop. At first, there was market resistance, buyers viewing the Tahiti lime as a "green lemon", and, for some time, Canadians would not accept it because they were accustomed to the more flavorful Mexican lime. In the 1930's, many Florida citrus growers planted limes for extra income and, in 1949, the development of limeade concentrate provided further impetus to the Tahiti lime industry.
In 1954, Libby, McNeil & Libby topworked 100 acres (40 ha) of grapefruit trees in Florida to Tahiti lime. Production increased 60% from 1970 to 1980. In 1979, the total crop was valued at close to $9 million. Nearly 1 million bushels (250 limes per bushel) were shipped fresh and the same amount was processed. By 1980, there were approximately 8,000 acres (about 3,250 ha) of commercial groves. Five years later, Dade County shipped 110 million lbs (50 million kg) of fresh fruit worth about $14 million to the growers, from a total of 6,500 acres (2,630 ha). Florida produces 90% of the national crop, for marketing fresh and for canned lime juice, frozen lime juice, frozen lime juice concentrate, frozen limeade and powdered lime juice. The Florida Lime and Avocado Administrative Committee conducts research on production and carries on national promotional activity.
There have been only a few named cultivars, or alleged cultivars, of the Tahiti lime:
'Bearss' ('Bearss Seedless', 'Byrum Seedless')This was first put forward as a new variety of Tahiti lime originating in the grove of T.J. Bearss at Porterville, California, in 1895. It was described and illustrated in 1902 and cultivated and catalogued by the Fancher Creek Nursery Company in 1905. It was grown in California, Arizona and Hawaii under the name, 'Bearss', at least until the late 1940's. However, comparative studies made in California led to the decision that the 'Bearss' did not differ sufficiently from the typical Tahiti lime to be maintained as a distinct cultivar.
'Idemor'a limb sport found around 1934 in a grove owned by G.L. Polk in Homestead, Florida, and patented in 1941 (U.S. Plant Patent #444). The fruit is smaller and more rotund than the typical Tahiti. A very similar sport has been reported from Morocco. This lime is no longer planted because of its susceptibility to virus diseases.
'Pond'In 1914, budwood was obtained by Dr. H.J. Webber from a Tahiti lime tree in the Moanalua Gardens, in Honolulu. Budded trees bore fruits that were somewhat smaller than the typical Tahiti but otherwise much the same. The trees were somewhat lower growing. This cultivar seems to have disappeared.
USDA 'No. 1' and 'No. 2'selections from many seedlings grown by Dr. James Childs of the United States Department of Agriculture at the Horticultural Field Station, Orlando, Florida. They are free of exocortis and xyloporosis viruses and are available to growers through Florida's Budwood Registration Program. The fruit does not differ significantly in character from the typical Tahiti lime. The development of these virus-free clones has been a great boon to Florida's lime industry.
The Tahiti lime is hardier than the Mexican lime and better adapted to the mainland of Florida. Most of the commercial groves are in Dade County, but, with some cold protection, this lime can be grown on the east and west coasts and the central ridge as far north as Winter Haven. Even in southern Florida, drastic drops in temperature have made it necessary to protect lime groves with wind machines or overhead sprinkling,
The plantings in southern Florida are on oolitic limestone. Those further north are on deep sand. The soil must be well drained. In low land subject to standing water, lime trees are planted on elevated beds.
The seeds of the Tahiti lime are largely monoembryonic; few seeds are available for planting; and seedlings, for the most part, are exceedingly variable. Only 10 trees of 114 seedlings grown at the Agricultural Research and Education Center of the University of Florida, Homestead, showed typical Tahiti lime characters vegetatively and in the fruit, except for long thorns on the trunk and branches.
This lime has been customarily budded onto rough lemon, but in recent years more commonly on the alemow, C. macrophylla. Many sweet orange and grapefruit trees have been successfully topworked to the Tahiti lime. Today, 40% of the commercial Tahiti lime trees have been grown from air-layers.
In Dade County's limestone, the trees are planted at the intersection of mechanically-cut trenches 16 in (40.5 cm) deep, or on mounds of crushed limestone and soil on scarified ground. The Tahiti lime tree is less vigorous than the Mexican lime and accordingly lends itself to close-planting. Spacing may be as close as 10 or 15 ft (3-4.5 m) in rows 20 ft (6 m) apart, which permits about 150 to 200 trees per acre (60-80/ha). When the trees overlap, they are mechanically hedged and topped. Greater yields will result if the trees are spaced at 20 ft (6 m) and hedging and topping are performed at 2 -to 3 -year intervals. The tree produces few water sprouts. A 12-month study in Cuba showed that hedging does not affect yield a year later, and does not alter the normal growth of the tree.
Air-layered trees begin to bear a year before budded trees but, as they mature, they generally do not yield as well. Because of their year-around growth, lime trees demand more fertilization and irrigation than other Citrus species. In commercial groves, irrigation is provided by overhead sprinklers, portable or stationery.
In early days, many trees were afflicted with bark lesions and even girdling, killing the affected branches or the entire tree if on the trunk. Splitting high-nitrogen fertilizer applications into 4 applications annually instead of 2 seemed to eliminate the problem. More recently, it has been recommended that a 4-6-6 formula of NPK be applied every 60 days. Potash is particularly important in relation to yield. In California, experimental spraying with gibberellic acid (10 ppm) delayed maturity and increased fruit size. The fruit stayed green longer in the packinghouse.
Tahiti limes are harvested 8 to 12 times a yearonce a month in winter, but 70% of the crop matures from May to fall. The peak period is July to September. The demand persists year-around and off-season fruits sell at premium prices. Most harvesting is by hand but some use a "gig". If picked too immature, the fruits will be deficient in juice. Since 1955, a Federal Marketing Order has prevented the harvesting of immature fruit and has provided for the industry's setting of standards of quality, grade and size. The minimum permissible juice content is 42%. If left too long on the tree, the fruits will be subject to stylar-end-breakdown and are apt to turn yellowish before they reach distant markets.
The limes are collected in wooden field boxes and conveyed by truck to packinghouses where they are graded, washed, waxed, and packed in 10-,20-,40-,or 55-lb (4.5-,9-,18-,or 25-kg) corrugated cartons for shipment to retailers. About 40% of the crop is processed locally for lime juice concentrate. Cull limes are shipped to out-of-state manufacturers of citrus juices and peel oil extractors. Limes for shipment to Hawaii and Arizona must be fumigated with methyl bromide because of possible infestation by Caribbean fruit fly.
The yield from 7 ft (2.13 m) trees grafted on alemow rootstock has averaged 90 lbs (41 kg), while trees of the same size on rough lemon yielded 63 lbs (29 kg). Under advanced methods of management, Florida lime groves produce 600 bushels per acre (243 bu/ha) annually.
The Tahiti lime requires no curing. The fresh fruits remain in good condition for 6 to 8 weeks under refrigeration.
Pests and Diseases
The citrus red mite (purple mite, red spider, spider mite), and the broad mite may heavily infest Tahiti lime leaves and fruits.
Formerly, the trees and fruits commonly evidenced lime blotch (yellow areas on leaves and fruits) but the replacing of susceptible trees has largely eliminated this problem. The tree is immune to withertip, moderately susceptible to scab and greasy spot. Red alga is a major problem, causing bark splitting and dieback of branches. It can be prevented by regular and thorough spraying with copper or other suitable fungicides. The tree is subject to several viruses: crinkly leaf, psorosis, tatterleaf , tristeza, exocortis and xyloporosis.
The fruits are highly subject to oil spotting (oleocellosis), which occurs most frequently during rainy seasons and when limes are harvested when wet with dew. Stylar-end-breakdown, or stylar-end-rot, has been a very serious post-harvest disorder in the summer. It may develop within 2 hours after picking or several days later. It is apparently induced in oversize fruits, larger than 2 1/2 in (6.25 cm) picked early in the morning when internal pressure is high and left too long in the hot sun in the field boxes. The effect is an expansion and rupturing of juice vesicles and the development of a brown, soft area at the apex of the fruit, occasionally at the base also. Fruit losses have been as high as 40%. Precooling the fruits for 24 hours greatly reduces the incidence of this disease.
The Tahiti lime is utilized for making limeade and otherwise for the same purposes as the Mexican lime. In Florida, a wedge of lime is commonly served with avocado, and lime juice is frequently used as an alternative to vinegar in dressings and sauces.
It was formerly held that the oil from the peel of the Tahiti lime was of inferior quality. Since the late 1960's, it has been accepted by the trade and produced in quantity as a by-product of the juice -extraction process. It is utilized for enhancing lime juice and for most of the other purposes for which Mexican lime peel oil is employed.
Excessive exposure to the peel oil of the Tahiti lime may cause dermatitis. Rolling the limes between the hands before squeezing in order to extract more of the juice will coat the hands with oil and this will be transferred to whatever parts of the body are touched before washing the hands. Subsequent exposure to sunlight often results in brown or red areas that itch intensely, and sometimes severe blistering. The sap of the tree and scratches by the thorns may cause rash in sensitive individuals.
Lime juice is employed as a rinse after shampooing the hair. Light streaks have been bleached in the hair by applying lime juice and then going out into the sun for a time. One should be sure that there is no peel oil on the hands when doing this. Lime juice has been applied on the face as a freshening lotion. Some Florida housewives use lime juice for cleaning the inside of coffeepots, and grind a whole lime in the electric garbage-disposal to eliminate unpleasant odor. Dilute lime juice will dissolve, overnight, calcium deposits in teakettles.
Medicinal Uses: Lime juice, given quickly, is an effective antidote for the painful oral irritation and inflammation that result from biting into aroids such as Dieffenbachia spp., Xanthosoma spp., Philodendron spp., and their allies. Lime juice has also been applied to relieve the effects of stinging corals.