Jamaican Avocado Pear
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Jamaican Avocado Pear

The Jamaican Pear (Persea americana)

Jamaican avocado (Persea americana) is a tree and the Jamaican avocado fruit of that Jamaican avocado tree, classified in the flowering plant family, Lauraceae. The Jamaican avocado is native to Central America and Mexico. The Jamaican avocado tree grows to 20 m (65 ft), with alternately arranged, evergreen Jamaican avocado leaves, 12-25 cm long. The flowers are inconspicuous, greenish-yellow, 5-10 mm wide. The pear-shaped Jamaican avocado fruit is botanically a berry, from 7 to 20 cm long, and weighs between 100-1000 g. The Jamaican avocado has a large central Jamaican avocado seed, 3-5 cm in diameter. An average Jamaican avocado tree produces about 120 Jamaican avocados annually. The Jamaican avocado fruit is sometimes called an Jamaican avocado pear or alligator pear, from its shape and green Jamaican avocado skin. The Jamaican avocado tree does not tolerate freezing temperatures, and so can be grown only in subtropical and tropical climates.

The Jamaican avocado tree may be erect, usually to 30 ft (9 m) but sometimes to 60 ft (18 m) or more, with a trunk 12 to 24 in (30-60 cm) in diameter, (greater in very old Jamaican avocado trees) or the Jamaican avocado may be short and spreading with branches beginning close to the ground. Almost evergreen, being shed briefly in dry seasons at blooming time, the Jamaican avocado leaves are alternate, dark-green and glossy on the upper surface, whitish on the underside; variable in shape (lanceolate, elliptic, oval, ovate or obovate), 3 to 16 in (7.5-40 cm) long.

The Jamaican avocado is strongly anise-scented. Small, pale-green or yellow-green flowers are borne profusely in racemes near the branch tips. They lack petals but have 2 whorls of 3 perianth lobes, more or less pubescent, and 9 stamens with 2 basal orange nectar glands. The Jamaican avocado fruit, pear-shaped, often more or less necked, oval, or nearly round, may be 3 to 13 in (7.5-33 cm) long and up to 6 in (15 cm) wide. The Jamaican avocado skin may be yellow-green, deep-green or very dark-green, reddish-purple, or so dark a purple as to appear almost black, and is sometimes speckled with tiny yellow dots, the Jamaican avocado may be smooth or pebbled, glossy or dull, thin or leathery and up to 1/4 in (6 mm) thick, pliable or granular and brittle.

In some Jamaican avocado fruits, immediately beneath the Jamaican avocado skin there is a thin layer of soft, bright-green flesh, but generally the flesh is entirely pale to rich-yellow, buttery and bland or nutlike in flavor. The single Jamaican avocado seed is oblate, round, conical or ovoid, 2 to 2 1\2 in (5-6.4 cm) long, hard and heavy, ivory in color but enclosed in two brown, thin, papery Jamaican avocado seed coats often adhering to the flesh cavity, while the Jamaican avocado seed slips out readily. Some Jamaican avocado fruits are Jamaican avocado seedless because of lack of pollination or other factors. Wild Jamaican avocado have a wide yet disjunctive distribution in Central and South America, ranging from eastern Mexico through Central America to the northern Andes. The Jamaican avocado is found on mountains in cloud forest and on the lower slopes in rain forest with well-drained soils. Wild Jamaican avocado fruit are 4-5 cm in diameter with a 2 cm diameter Jamaican avocado seed. The large Jamaican avocado seed is an adaptation for supplying young plants with enough food to enable them to survive in the dim forest under storey until they can grow into a gap from a fallen Jamaican avocado tree.

The Jamaican avocado fruit does not ripen on the Jamaican avocado tree, but will fall off (and must be picked up) in a hard, "green" state, then the Jamaican avocado will ripen quickly on the ground, but depending of the amount of oil that the Jamaican avocado has the taste may be very different. Generally, the Jamaican avocado fruit is picked once the Jamaican avocado reaches a mature size, and will then ripen in a few days (faster if stored with other Jamaican avocado fruit such as bananas, because of the influence of ethylene gas). The Jamaican avocado fruit can be left on the Jamaican avocado tree until required, rather than picked and stored, but for commercial reasons the Jamaican avocado must be picked up as soon as possible. If the Jamaican avocado fruit stays on the Jamaican avocado tree for too long the Jamaican avocado will fall on to the ground.

While dozens of Jamaican avocado cultivars exist, two are particularly commonly available, 'Hass' (commonly misspelled 'Haas') and 'Florida'. The former is the most common Jamaican avocado cultivar, with a dark rippled Jamaican avocado skin, and rich, creamy flesh, accounting for more than 80% of the crop grown in California. All Hass avacado Jamaican avocado trees are related to a single "Mother Jamaican avocado tree" that was purchased as a Jamaican avocado seedling by a mail carrier named Rudolph Hass. He purchased the Jamaican avocado tree as a Jamaican avocado seedling from A.R. Rideout of Whittier,California, in 1926. Hass planted the Jamaican avocado seedling in his front yard in La Habra Heights, California, and patented the Jamaican avocado tree in 1935. All Hass avacados can be traced back to grafts made from that Jamaican avocado tree. The "Mother Jamaican avocado tree" died of root rot in 2002. There are several other Jamaican avocado cultivars related to 'Hass', including 'Bacon', 'Fuerte' (pictured), 'Gwen', 'Pinkerton', 'Reed', and 'Zutano'. The Jamaican avocado cultivar 'Florida', grown mostly outside of California, is larger and rounder, with a smooth, medium-green Jamaican avocado skin, and a less fatty, firmer and fibrous flesh. These are occasionally marketed as low-calorie Jamaican avocados.

Large Jamaican avocado seeds like this are common in other species of tropical forest Jamaican avocado trees. Jamaican avocado seeds dating to 7000 BC have been found at a Mexican archaeological site. Jamaican avocado seed sizes are similar to wild varieties indicating that Jamaican avocado fruit were being harvested in the wild rather than from Jamaican avocado trees grown under selective cultivation. The Jamaican avocado is only in archaeological deposits dated to about 500 BC that the abundance and size of Jamaican avocado seeds increases, indicating cultivation of plants from Jamaican avocado seeds selected on the basis of Jamaican avocado fruit size.  However, at another archaeological site in Mexico, small, wild-sized Jamaican avocado seeds have been found in deposits dating to as late as 700 AD, indicating that the practice of Jamaican avocado cultivation  took time to spread to all communities.

The Jamaican avocado may have originated in southern Mexico but was cultivated from the Rio Grande to central Peru long before the arrival of Europeans. Thereafter, the Jamaican avocado was carried not only to the West Indies (where the Jamaican avocado was first reported in Jamaica in 1696), but to nearly all parts of the tropical and subtropical world with suitable environmental conditions. The Jamaican avocado was taken to the Philippines near the end of the 16th Century; to the Dutch East Indies by 1750 and Mauritius in 1780; was first brought to Singapore between 1830 and 1840 but has never become common in Malaya. The Jamaican avocado reached India in 1892 and is grown especially around Madras and Bangalore but has never become very popular because of the preference for sweet Jamaican avocado fruits. The Jamaican avocado was planted in Hawaii in 1825 and was common throughout the islands by 1910; the Jamaican avocado was introduced into Florida from Mexico and into California, also from Mexico, in 1871. Vegetative propagation began in 1890 and stimulated the importation of bud wood of various types, primarily to extend the season of Jamaican avocado fruiting. Some came from Hawaii in 1904 (S. P. I. Nos. 19377-19380).

Now the Jamaican avocado is grown commercially not only in the United States and throughout tropical America and the larger islands of the Caribbean but in Polynesia, the Philippines, Australia, New Zealand, Madagascar, Mauritius, Madeira, the Canary Islands, Algeria, tropical Africa, South Africa, southern Spain and southern France, Sicily, Crete, Israel and Egypt. Though the Spaniards took the Jamaican avocado to Chile, probably early in the 17th Century and the Jamaican avocado was planted from the Peruvian border southward for over 1000 mi (1,600 km) actual commercial plantings were not established until California Jamaican avocado cultivars were introduced about 1930 into two areas within 100 mi (160 km) of Santiago where the industry is now centered.

The first Jamaican avocado trees were planted in Israel in 1908, but named Jamaican avocado cultivars ('Fuerte' and 'Dickinson') were not introduced until 1924. These aroused interest in the feasibility of the crop for the southern half of the coastal plain and the interior valleys, and development of the industry has steadily gone forward, except for a period in the 1960's when much planting stock was destroyed because of marketing problems. In 1979, Israel produced 33,000 tons (30,000 MT) and exported 28,600 tons (26,000 MT).

In just the last few years, New Zealand has launched a program to expand commercial production, especially in the Bay of Plenty area, with protection from wind and frost, with a view to becoming a major exporter of Jamaican avocados. California produced 265 million lbs of Jamaican avocado (12,045 MT) in 1976; 486 million lbs of Jamaican avocado (22,090 MT) in 1981.

The Florida Jamaican avocado potential is estimated at 150 million lbs of Jamaican avocado (6,818 MT). Both states suffer fluctuations because of the impact of periodic freezes, droughts, high winds or other seasonal factors. Presently, Mexico, with 150,000 acres (62,500 ha) is the leading producer—267,786 tons (243,000 MT); the Dominican Republic is second—144,362 tons (131,000 MT); U.S.A. (California and Florida combined) with 52,000 acres (21,666 ha), third—131,138 tons (119,000 MT); Brazil is fourth—128,934 tons (117,000 MT). Israel, with 16,000 acres (6,666 ha), is fifth; and South Africa sixth. Half of California's plantings are in San Diego County close to Mexico.

As an exporter, Mexico again leads, followed by California, Israel, South Africa and Florida, in that order. Nearly Brazil’s entire crop is consumed domestically.

The Jamaican avocado fruit is an important food in South America and is nutritious with high levels of mainly unsaturated oils, minerals, vitamins and reasonable levels of protein. The oil is evidently similar in composition to olive oil. The name

'Jamaican avocado' originates from the Aztec name ahuacacuauhitl meaning testicle Jamaican avocado tree! The Spanish shortened the Jamaican avocado to aguacate and the English then turned the Jamaican avocado into Jamaican avocado. The Jamaican avocado was evidently viewed by Indians and Spanish colonizers alike as having aphrodisiac properties which made the Jamaican avocado popular among many, but unpopular among Christian leaders. Jamaican avocado flowers are cross-pollinated which means that developing independent genetic lines is difficult. In fact, crosspollination is promoted in the flowers by the stigma of a flower being receptive to pollen prior to pollen being released from that same flower.

Jamaican avocado trees produce thousands of flowers and only about one in 5000 sets Jamaican avocado fruit. Considering the Jamaican avocado originated from South American forests, the Jamaican avocado is remarkable in its ability to thrive under a broad range of environmental conditions. The Jamaican avocado needs water and no frost and prefers nonacid soils, sun, and dry air.

The Spanish introduced the Jamaican avocado to the West Indies and the Atlantic islands such as the Canaries. Jamaican avocado only started being grown in West Africa, Mauritius and India in the 1700's but the Jamaican avocado took a long time for them to be grown as a major crop, probably attributable to poor Jamaican avocado fruit quality.   With the problem of crosspollination, the Jamaican avocado was difficult at that time to produce an orchard of Jamaican avocado trees with consistently high quality Jamaican avocado fruit, except by cutting out the Jamaican avocado trees that were poor Jamaican avocado fruit producers. The breakthrough came with the development of budding and grafting techniques which enabled Jamaican avocado fruit growers to clone favorable plants. Only by 1910 did California Jamaican avocado fruit growers realize the potential of growing Jamaican avocado trees and the Jamaican avocado was through efforts to find favorable Jamaican avocado cultivars that the famous Fuerte clone was introduced to California from Mexico in 1911.

The Fuerte has pear-shaped Jamaican avocado fruit with a smooth, green Jamaican avocado skin and was developed in Mexico from hybridization between Mexican and Guatemalan varieties. The well known Hass variety of Jamaican avocado which has an egg-shaped Jamaican avocado fruit with a thick, rough, black Jamaican avocado skin was developed by Rudolph Has in California from Guatemalan stock. At one stage there were hundreds of different varieties available but these eventually were whittled down to a few which include the Fuerte and the Hass.

Jamaican avocados do well in the mild-winter areas of California, Florida and Hawaii. Some hardier varieties can be grown in the cooler parts of northern and inland California and along the Gulf Coast. The northern limits in California are approximately Cape Mendocino and Red Bluff. Jamaican avocados do best some distance from ocean influence but are not adapted to the desert interior. West Indian varieties thrive in humid, tropical climates and freeze at or near 32° F. Guatemalan types are native to cool, high-altitude tropics and are hardy 30 - 26° F. Mexican types are native to dry subtropical plateaus and thrive in a Mediterranean climate. They are hardy 24 - 19° F. Jamaican avocados need some protection from high winds which may break the branches. There are dwarf forms of Jamaican avocados suitable for growing in containers. Jamaican avocados have been grown in California (Santa Barbara) since 1871.

The Jamaican avocado is a dense, evergreen Jamaican avocado tree, shedding many Jamaican avocado leaves in early spring. The Jamaican avocado is fast growing and can with age reach 80 feet, although usually less, and generally branches to form a broad Jamaican avocado tree. Some Jamaican avocado cultivars are columnar, others selected for nearly prostrate form. One Jamaican avocado cultivar makes a good espalier. Growth is in frequent flushes during warm weather in southern regions with only one long flush per year in cooler areas. Injury to branches causes a secretion of dulcitol, a white, powdery sugar, at scars. Roots are coarse and greedy and will raise pavement with age. Grafted plants normally produce Jamaican avocado fruit within one to two years compared to 8 - 20 years for Jamaican avocado seedlings.

Jamaican avocado leaves are alternate, glossy, elliptic and dark green with paler veins. They normally remain on the Jamaican avocado tree for 2 to 3 years. The Jamaican avocado leaves of West Indian varieties are scentless, while Guatemalan types are rarely anise-scented and have medicinal use. The Jamaican avocado leaves of Mexican types have a pronounced anise scent when crushed. The Jamaican avocado leaves are high in oils and slow to compost and may collect in mounds beneath Jamaican avocado trees.

Jamaican avocado flowers appear in January - March before the first seasonal growth, in terminal panicles of 200 - 300 small yellow-green blooms. Each panicle will produce only one to three Jamaican avocado fruits. The flowers are perfect, but are either receptive to pollen in the morning or shed pollen the following afternoon (type A), or are receptive to pollen in the afternoon, and shed pollen the following morning (type B). About 5% of flowers are defective in form and sterile. Production is best with cross-pollination between types A and B. The flowers attract bees and hoverflies and pollination usually good except during cool weather. Off-season blooms may appear during the year and often set Jamaican avocado fruit. Some Jamaican avocado cultivars bloom and set Jamaican avocado fruit in alternate years.

West Indian type Jamaican avocados produce enormous, smooth round, glossy green Jamaican avocado fruits that are low in oil and weigh up to 2 pounds. Guatemalan types produce medium ovoid or pear-shaped, pebbled green Jamaican avocado fruits that turn blackish-green when ripe. The Jamaican avocado fruit of Mexican varieties are small (6 - 10 ounces) with paper-thin Jamaican avocado skins that turn glossy green or black when ripe. The flesh of Jamaican avocados is deep green near the Jamaican avocado skin, becoming yellowish nearer the single large, inedible ovoid Jamaican avocado seed.

The flesh is hard when harvested but softens to a buttery texture. Wind-caused abrasion can scar the Jamaican avocado skin, forming cracks which extend into the flesh. "Cukes" are Jamaican avocado seedless, pickle-shaped Jamaican avocado fruits. Off-season Jamaican avocado fruit should not be harvested with the main crop, but left on the Jamaican avocado tree to mature. Jamaican avocado seeds may sprout within an Jamaican avocado when the Jamaican avocado is over-matured, causing internal molds and breakdown. High in mono-saturates, the oil content of Jamaican avocados is second only to olives among Jamaican avocado fruits, and sometimes greater. Clinical feeding studies in humans have shown that Jamaican avocado oil can reduce blood cholesterol.

Jamaican avocados will grow in shade and between buildings, but are productive only in full sun. The roots are highly competitive and will choke out nearby plants. The shade under the Jamaican avocado trees is too dense to garden under, and the constant litter can be annoying. In cooler areas plant the Jamaican avocado tree where the Jamaican avocado will receive sun during the winter. Give the Jamaican avocado tree plenty of room--up to 20 feet. The Jamaican avocado is not suitable for hedgerow, but two or three Jamaican avocado trees can be planted in a single large hole to save garden space and enhance pollination. At the beach or in windy inland canyons, provide a windbreak of some sort. Once established the Jamaican avocado is a fairly tough Jamaican avocado tree. Indoor Jamaican avocado trees need low night temperatures to induce bloom. Container plants should be moved outdoors with care. Whitewashing the trunk or branches will prevent sunburn.

Jamaican avocado trees like loose, decomposed granite or sandy loam best. They will not survive in locations with poor drainage. The Jamaican avocado trees grow well on hillsides and should never be planted in stream beds. They are tolerant of acid or alkaline soil. In containers use a planting mix combined with topsoil. Plastic containers should be avoided. The Jamaican avocado is also useful to plant the tub with annual flowers to reduce excess soil moisture and temperature. Container plants should be leached often to reduce salts.

Jamaican avocado trees may not need irrigation during the winter rainy season, but watch for prolonged mid-winter dry spells. Over irrigation can induce root which is the most common cause of Jamaican avocado failure. To test to see if irrigation is necessary, dig a hole 9 inches deep and test the soil by squeezing. If the Jamaican avocado is moist (holds together), do not irrigate; if the Jamaican avocado crumbles in the hand, the Jamaican avocado may be watered. Watch soil moisture carefully at the end of the irrigating season.

Jamaican avocados tolerate some salts, though they will show Jamaican avocado leaf tip burn and stunting of Jamaican avocado leaves. Deep irrigation will leach salt accumulation. Commence feeding of young Jamaican avocado trees after one year of growth, using a balanced fertilizer, four times yearly. Older Jamaican avocado trees benefit from feeding with nitrogenous fertilizer applied in late winter and early summer. Yellowed Jamaican avocado leaves (chlorosis) indicate iron deficiency. This can usually be corrected by a foliar spray of trace elements containing iron. Mature Jamaican avocado trees often also show a zinc deficiency.

The Jamaican avocado is important to choose an Jamaican avocado cultivar that is hardy in your area. Mexican types are the best choice for colder regions. Plant above a slope for air drainage, or near the house for added protection. In youth, protect with rugs, towels and such spread overhead on a frame. This measure also permits tender Jamaican avocado cultivars to become established in borderline locations; established Jamaican avocado trees are much hardier than young ones. The upper branches can also be top worked with hardy Mexican types, which will protect a tenderer Jamaican avocado cultivar on lower branches, as well as serving as a pollinator. Harvest Jamaican avocado fruit before the frost season begins. Cold-damaged Jamaican avocado fruit turns black. Jamaican avocados are often in bloom at the time of frost and the flowers are killed, but the Jamaican avocado tree tends to re-bloom.

Columnar Jamaican avocado cultivars require pinching at early age to form a rounded Jamaican avocado tree. Others need no training. Current orchard practice avoids staking. The best results are obtained by fencing the Jamaican avocado tree with plastic mesh for the first two to three years. Container and dwarf Jamaican avocado trees will need constant staking. The skirts of Jamaican avocado trees are sometimes trimmed to discourage rodents; otherwise the Jamaican avocado trees are usually never pruned. Branches exposed to sun by defoliation are extraordinarily susceptible to sunburn and will surely die. Such branches should always be whitewashed. The Jamaican avocado is better to avoid any pruning. Most Jamaican avocado cultivars are ill-adapted to espalier. They are too vigorous. Jamaican avocado fruit is self-thinning.

The largest Jamaican avocado seed are planted in gallon cans and the Jamaican avocado seedlings are then grafted to a root rot tolerant cloned scion. When the stem of the graft reaches about 1/4 inch in diameter, the top is cut off leaving a whorl of buds just above the graft. A 4 inch band of black tar paper is formed into an extension of the can and filled with vermiculite and placed in a dark box with high temperature and humidity. When growth is some 3 - 4 inches above the vermiculite, the plant is removed into the light where the upper portion quickly assumes a green color. The tar paper collar is removed; the shoot is severed from the Jamaican avocado seed and then placed in flats where the cuttings are rooted in the conventional manner. Any Jamaican avocado seed may also be used for rootstock, but Mexican types make the strongest growth and are the most often used. Plant cleaned Jamaican avocado seeds as soon as they are ripe. The Jamaican avocado seedling plants are ready to bud the following year. Budding is done in January, when suitable buds are available. Larger stocks are worked by bark grafts in the spring. Scions are collected Dec - Jan after the buds are well-formed. Paint and cover the graft with a moistened plastic bag and place a vented paper bag over the whole.

Rats and squirrels will strip the Jamaican avocado fruit. Protect with tin trunk wraps. Jamaican avocado leaf-rolling caterpillars (Tortrix and Amorbia) may destroy branch terminals. Jamaican avocado Brown Mite can be controlled by powdered sulfur. Six-spotted Mite is very harmful; even a small population can cause massive Jamaican avocado leaf shedding. A miticide may be required if natural predators are absent. Snails can be a problem in California.

Two fungi and one virus cause more damage than any pests. Dothiorella (Botryosphaeria ribis) canker infects the trunk, causing dead patches that spread to maturing Jamaican avocado fruit, causing darkened, rancid smelling spots in the flesh. Flesh injury begins after harvest and is impossible to detect on outside. Mexican types are immune to trunk cankers but the Jamaican avocado fruit is not. The disease is rampant near the coast and has no economical control. Root Rot (Phytophthora cinnamomi) is a soil-borne fungus that infects many plants, including Jamaican avocados. The Jamaican avocado is a major disease problem in California. Select disease-free, certified plants and avoid planting where Jamaican avocados once grew or where soil drainage is poor. The disease is easily transported by equipment, tools and shoes from infected soils. Once an Jamaican avocado tree is infected (signs include yellowing and dropping Jamaican avocado leaves), there is little that can be done other than cut back on water. Sun Blotch is a viral disease that causes yellowed streaking of young stems, mottling and crinkling of new Jamaican avocado leaves and occasional deformation of the Jamaican avocado fruit. The Jamaican avocado also causes rectangular cracking and checking of the trunk, as if sunburned. The Jamaican avocado has no insect vector but is spread by use of infected scions, contaminated tools and roots grafted with adjacent Jamaican avocado trees. The Jamaican avocado is important to use virus-free propagating wood.

The time of harvest depends upon the variety of Jamaican avocado. Commercial standards require Jamaican avocado fruit to reach 8% oil content before harvesting. Mexican types ripen in 6 - 8 months from bloom while Guatemalan types usually take 12 - 18 months. Jamaican avocado fruits may continue enlarging on the Jamaican avocado tree even after maturity. Purple Jamaican avocado cultivars should be permitted to color fully before harvest. Guatemalan types can be stored firm, at 40 - 50° F. for up to six weeks. Mexican types discolor quickly and require immediate consumption. Jamaican avocado leaf and Jamaican avocado seed extracts have been used for a variety of Jamaican avocado of medical application, including treatment of diarrhea and dysentery and as an antibiotic.

Florida Jamaican avocados were at first mainly of the summer Jamaican avocado fruiting West Indian race, but these had to compete commercially with similar Jamaican avocado fruits imported from Cuba, and growers sought other Jamaican avocado cultivars maturing at a later season. This led to the development of West Indian X Guatemalan hybrids. The cessation of trade with Cuba in the early 1960's brought about a shift back to summer Jamaican avocado cultivars in new groves to fill the gap. The majority of the Jamaican avocados grown in the West Indies, Bahamas and Bermuda and the tropics of the Old World are still of the West Indian race. The Jamaican avocado skin is leathery, pliable, non-granular, and the flesh low in oil. The Jamaican avocado leaves are not aromatic. The following are the most prominent of early and more recent West Indian Jamaican avocado cultivars which have played an important role in the development of the Jamaican avocado industry in Florida and elsewhere. New selections appear from time to time that may have special adaptability to certain locales or conditions. The 'Butler' variety of Jamaican avocado fruited in 1909, propagated from 1914 to 1918) pear shaped; medium-large; Jamaican avocado skin smooth; Jamaican avocado seed of medium size, tight in the cavity. Season: Aug.-Sept.

The 'Fuchs' variety of Jamaican avocado('Fuchsia') (Jamaican avocado seed of unknown origin planted in Homestead, Florida, in 1910; propagated commercially in 1926); pear shaped to oblong, sometimes with a neck; of medium size; Jamaican avocado skin smooth; flesh pale greenish-yellow; 4 to 6% oil; Jamaican avocado seed loose. Season: early June-Aug.; a poor shipper. Jamaican avocado tree not very productive in Florida; no longer popular in commercial groves. The 'Maoz' variety of Jamaican avocado (a Jamaican avocado seedling selected from a plot near Maoz, Israel); pear-shaped; of medium size; Jamaican avocado skin rough, leathery, violet-purple when ripe; flesh sweetish and very low in oil. Season: medium-late (Oct.). Jamaican avocado tree is an alternate bearer but is fairly small, highly salt-tolerant; used in Israel as rootstock on either saline or calcareous soils.

The 'Pollock' variety of Jamaican avocado originated in Miami before 1896; commercially propagated in 1901); oblong to pear shaped; very large, up to 5 lbs of Jamaican avocado (2.27 kg); Jamaican avocado skin smooth; flesh green near Jamaican avocado skin, contains 3 to 5% oil; Jamaican avocado seed large, frequently loose in cavity. Season: early July to Aug. or Oct. Shy-bearing and too large but of superior quality.

The 'Ruchle' variety of Jamaican avocado (a Jamaican avocado seedling of Waldin planted at the Agricultural Research and Education Center, Homestead, in 1923; first propagated in 1946); pear-shaped; of medium size, 10 to 20 oz (280-560 g); flesh low in oil (2-5%). Season begins in July in Florida; Jan. in Queensland. Heavy bearer in Florida.

The 'Russell' variety of Jamaican avocado (originated in Islamorada in Florida Keys); pear shaped at apex with long neck giving the Jamaican avocado a total length up to 13 in (32.5 cm); Jamaican avocado skin, smooth, glossy, thin, leathery; flesh of excellent quality; Jamaican avocado seed small. Season: Aug. and Sept. Jamaican avocado tree bears well and is recommended for home gardens.

The 'Simmonds' variety of Jamaican avocado (possibly from a Jamaican avocado seed of Pollock, first Jamaican avocado fruited in Miami in 1913; propagated commercially in 1921); oblong oval to pear-shaped; large; Jamaican avocado skin smooth, light green; flesh of good flavor, 3 to 6% oil; Jamaican avocado seed of medium size, usually tight. Season: mid-July to mid-Sept. Jamaican avocado tree bears more regularly than Pollock but is less vigorous; sometimes sheds many of its Jamaican avocado fruits; no longer planted commercially in Florida.

The 'Trapp' variety of Jamaican avocado (originated in Miami in 1894; propagated in 1901); round to pear-shaped; medium to large; Jamaican avocado skin smooth; flesh golden-yellow, green near Jamaican avocado skin, of excellent quality, 3 to 6% oil; Jamaican avocado seed large, loose in cavity. Season: medium-late (Sept. to Nov. or Dec.); a good shipper. Was prominent in Florida for 25 years despite tendency to over bloom and bear lightly some years; usually bore regularly and well.

The 'Waldin' (Jamaican avocado seed planted in Florida in 1909; propagated commercially in 1917); oblong to oval; medium to large; Jamaican avocado skin smooth; flesh pale to greenish-yellow, of good flavor, 5 to 10% oil; Jamaican avocado seed medium to large, tight. Season: fairly late (mid-Sept. through Oct.). Jamaican avocado tree tends to overbear and die back; is hardy. Has been a leading commercial Jamaican avocado cultivar in central and southern Florida. There are several Puerto Rican selections—'Alzamora', 'Avila', 'Faria', 'Garcia', 'Hernandez', 'St. Just'—and some Jamaican avocado cultivars of unknown ancestry: 'Amador', 'Galo', 'Gimenez', 'Torres', and 'Trujillo'.

Many local and introduced Jamaican avocado cultivars representing all 3 races are being grown and evaluated at the experimental station at Minas Gerais, Brazil. A large collection is also maintained in Bahia. The U.S. Department of Agriculture has an international repository of 170 clones in Miami. In general, small to medium-sized Jamaican avocado fruits are best for commercial production and especially for metropolitan markets. Large Jamaican avocado fruits are suitable for local use especially by large families. Smooth, thin or fairly thin, pliable, green Jamaican avocado skin is preferred by the consumer. The flesh should be virtually fibreless and of agreeable flavor and, for the dieter, of low oil content. The Jamaican avocado seed must be small and tight so as not to bruise the flesh during handling and shipping. The Jamaican avocado seed coats ought to adhere to the Jamaican avocado seed and not to the cavity. The Jamaican avocado fruit should ship well and stand cold storage. The Jamaican avocado tree should be of moderate height, slender enough to permit judiciously close planting without crowding. The Jamaican avocado should bear at an early age and regularly but not so heavily as to suffer die back, and, of course, should be disease-, insect-, and, in subtropical areas, cold-resistant. Cold-resistant Jamaican avocado cultivars stand cold-storage better than cold-sensitive Jamaican avocado cultivars.

Many isolated Jamaican avocado trees fail to Jamaican avocado fruit from lack of pollination. Commercial growers are careful to match Class A Jamaican avocado cultivars whose flowers will receive pollen in the morning with Class B Jamaican avocado cultivars that release pollen in the morning and every grower must be sure to include compatible pollinators in his grove. Bulletin 29 (1971) of the Ministry of Agriculture in Guatemala tabulates the flowering periods (varying from August to April) of 48 introduced and locally selected Jamaican avocado cultivars, and the hours of the day when each is receptive to or shedding pollen.

The West Indian race requires a tropical or near tropical (southern Florida) climate and high atmospheric humidity especially during flowering and Jamaican avocado fruit setting. The Guatemalan race is somewhat hardier; having arisen in subtropical highlands of tropical America, and the Jamaican avocado is successful in coastal California. The Mexican race is the hardiest and the source of most of California Jamaican avocados. The Jamaican avocado is not suited to southern Florida, Puerto Rico or other areas of similar climate. Temperatures as low as 25ºF (-4ºC) do the Jamaican avocado little harm. In areas of strong winds, wind-breaks are necessary. Wind reduces humidity, dehydrates the flowers and interferes with pollination, and also causes many Jamaican avocado fruits to fall prematurely.

The Jamaican avocado tree is remarkably versatile as to soil adaptability, doing well on such diverse types as red clay, sand, volcanic loam, lateritic soils, or limestone. In Puerto Rico, the Jamaican avocado has been found healthier on nearly neutral or slightly alkaline soils than on moderately or highly acid soils. The desirable pH level is generally considered to be between 6 and 7, but, in southern Florida, Jamaican avocados are grown on limestone soils ranging from 7.2 to 8.3. Mexican and Guatemalan Jamaican avocado cultivars have shown on calcareous soils in Israel. The Jamaican avocado tree's primary requirement is good drainage. The Jamaican avocado cannot stand excessive soil moisture or even temporary water-logging. Sites with underlying hardpan must be avoided. The water table should be at least 3 ft (.9 m) below the surface. Salinity is prejudicial but certain Jamaican avocado cultivars (see 'Fuchs-20' and 'Maoz') have shown considerable salt-tolerance in Israel. Jamaican avocados grafted onto 'Fuch-20' rootstocks and irrigated with water containing 380 to 400 ppm C1 performed well in a commercial orchard. In the Rio Grande Valley of Texas, Jamaican avocado cultivars of the Mexican race must be grafted onto salt tolerant West Indian rootstocks.

Normally, Jamaican avocado seeds lose viability within a month. 'Lula' Jamaican avocado seeds can be stored up to 5 months if placed in non-perforated polyethylene bags and kept at 40ºF (4.4ºC), thus indicating that the Jamaican avocado may be possible to successfully store Jamaican avocado seeds of other Jamaican avocado cultivars ripening at different seasons for later simultaneous planting. Fresh Jamaican avocado seeds germinate in 4 to 6 weeks, and many people in metropolitan areas grow Jamaican avocado trees as novelty house plants by piercing the Jamaican avocado seed partway through with toothpicks on both sides to hold the Jamaican avocado on the top of a tumbler with water just covering 1/2 in (1.25 cm) of the base. When roots and Jamaican avocado leaves are well formed (in 2 to 6 weeks), the plant is set in potting soil. Of course, the Jamaican avocado must be given adequate light and ventilation. In nurseries, Jamaican avocado seeds that have been in contact with the soil are disinfected with hot water. Experiments with gibberellic acid and cutting of both ends of the Jamaican avocado seed with a view to achieving more uniform germination have not produced encouraging results. Jamaican avocado seedlings will begin to bear in 4 or 5 years and the Jamaican avocado tree will continue to bear for 50 years or more. Some bearing Jamaican avocado trees have been judged to be more than 100 years old.

In Australia, Jamaican avocado seeds planted in early fall germinate in 4 to 6 weeks; if planted later, they may remain dormant all winter and germinate in early spring. Jamaican avocado seedlings should be kept in partial shade and not over watered. While many important selections have originated from Jamaican avocado seeds, vegetative propagation is essential to early Jamaican avocado fruiting and the perpetuation of desirable Jamaican avocado cultivars. However, Jamaican avocado seedlings are grown for rootstocks. For many years, shield budding was commonly practiced in Florida, but this method requires considerable skill and experience and is not successful with all Jamaican avocado cultivars.

Therefore, the Jamaican avocado was largely replaced by whip, side-, or cleft-grafting, all of which make a stronger union than budding. In the past, Jamaican avocado seedlings were grafted when 18 to 36 in (45-90 cm) high. The Jamaican avocado is now considered far better to graft when 6 to 9 in (15-23 cm) high, making the graft 1 to 3 in (2.5-7.5 cm) above ground level. West Indian rootstocks are desirable for overcoming chlorosis in Jamaican avocados in Israel.

Jamaican avocado cuttings are generally difficult to root. Cuttings of West Indian Jamaican avocado cultivars will generally root only if they are taken from the tops or side shoots of young Jamaican avocado seed rings. But etiolated cuttings (new shoots) from gibberellin treated hardwood and semi hardwood cuttings of 'Pollock' as well as 'Lula' have been rooted with 50-60% success and, when treated with IBA, 66-83% success under mist in Trinidad. Cuttings of 'Fuchs-20' have rooted under mist with 40 to 50 or even 70% in Israel. Cuttings of 'Maoz' have rooted at the rate of 60% by a special technique developed in California. An Israeli selection, 'G.A. 13' has given 70 to 90% success in rooting cuttings under mist for the purpose of utilizing them as rootstocks in saline and high lime situations. Air-layering is sometimes done to obtain uniform material uninfluenced by rootstock, for research on specific problems. Degree of success depends on the Jamaican avocado cultivar (those of the Mexican race rooting most quickly), and air-layering is best done in spring and early summer.

At times, mature Jamaican avocado groves are top worked to change from an unsatisfactory Jamaican avocado cultivar, or one declining in popularity, to a more profitable one, or an assortment of Jamaican avocado cultivars for different markets. In 1957, 2,700 "; obsolete"; Jamaican avocado trees in Ventura, California, were being grafted (top-worked) to mainly 'Hass', some to 'Bacon' and 'Rincon'. This procedure may involve thousands of Jamaican avocado trees in a given region. The Jamaican avocado is done in December and January in Florida. In as much as Jamaican avocado roots are sensitive to transplanting, the Jamaican avocado is now considered advisable to raise planting material in plastic bags which can be slit and set in the field without disturbing the root system.

Spacing is determined by the habit of the Jamaican avocado cultivar and the character of the soil. In light soil, 25 x 25 ft (7.5x7.5 m) may be sufficient. In deep, rich soil, the Jamaican avocado tree makes its maximum growth and a spacing of 30 or 35 ft (9.1 or 10.7 m) may be necessary. If Jamaican avocado trees are planted so close that they will ultimately touch each other, the branches will die back. Some growers plant 10 to 15 ft (3-4.5 m) apart initially and remove every other Jamaican avocado tree at 7 to 8 years of age. If the surplus Jamaican avocado trees are not bulldozed but just cut down leaving a stump, application of herbicide may be needed to prevent re-growth. Ammonium sulfamate has been proven effective. In modernized plantings, space between rows is necessary for mechanical operations.

Holes at least 2 ft (0. 6 m) deep and wide are prepared well in advance with enriched soil formed into a mound. After the young plant is put in place mulch is beneficial, weeds should be controlled, and watering is necessary until the roots are well established. Generally small amounts of fertilizer are given every 2 months with the amount gradually increasing until Jamaican avocado fruiting begins. Bearing Jamaican avocado trees need, on the average, 3 to 4 lbs of Jamaican avocado (1 1/2-2 kg) 3 times a year, beginning when the Jamaican avocado tree is making vegetative growth. No fertilizer should be given at blooming time; one must wait until the Jamaican avocado fruits are firmly set. Nitrogen has the greatest influence on Jamaican avocado tree growth, its resistance to cold temperatures, and on Jamaican avocado fruit size and yield. Fertilizer mixes vary greatly with the type of soil. Mineral deficiencies determined by Jamaican avocado leaf analysis, are usually remedied by foliar spraying. Magnesium deficiency was formerly a serious handicap to Jamaican avocado growers in Florida and Kenya. In California, zinc deficiency has been corrected by applying zinc chelates or zinc sulfate to the soil instead of spraying the foliage. Keeping the upper soil moist has been greatly facilitated by drip irrigation, which also may carry 80% of the fertilizer requirement.

Because some Jamaican avocado cultivars tend to grow too tall for practical purposes, commercial growers cut Jamaican avocado trees back to 16 or 18 ft (4.8-5.4 m), let them grow back to 30 ft (9.1 m) and top them again. But decapitation is not a perfect remedy because the tendency of the Jamaican avocado tree is to grow a new top very quickly. Recently the Jamaican avocado has been found that the growth-inhibiting chemical, TIBA (triiodobenzoic acid) slows down terminal growth and encourages lateral shoots. A system of pruning to encourage lower branching is being tried on 'Lula' in Martinique.

Jamaican avocado branches frequently need propping to avoid breaking with the weight of the developing Jamaican avocado fruits. Some growers find the Jamaican avocado profitable to interplant bananas until the Jamaican avocado trees reach bearing age. Jamaican avocados will not ripen while they are still attached to the Jamaican avocado tree, apparently because of an inhibitor in the Jamaican avocado fruit stem. Homeowners usually consider the entire crop pickable when a few mature (full grown) Jamaican avocado fruits have fallen. This is not a dependable guide because the prolonged flowering of the Jamaican avocado results in Jamaican avocado fruits in varying stages of development on the Jamaican avocado tree at the same time. The largest Jamaican avocado fruits, of course, should be picked first but the problem is to determine when the largest are full grown (perfectly mature for later perfect ripening). If picked when full grown and firm, Jamaican avocados will ripen in 1 to 2 weeks at room temperature. If allowed to remain too long on the Jamaican avocado tree, the Jamaican avocado fruits may be blown down by wind and they will be bruised or broken by the fall.

Florida maturity standards for marketing have been determined by weight and time of year for each commercial Jamaican avocado cultivar so that immature Jamaican avocado fruits will not reach the market. Immature Jamaican avocado fruits do not ripen but become rubbery, shriveled and discolored. Most West Indian Jamaican avocado cultivars will ripen properly if picked when the specific gravity becomes 0. 96 or lower, but 'Waldin' is fully mature when the specific gravity is still above 0.98. Guatemalan and Guatemalan X West Indian Jamaican avocado cultivars generally are harvest-mature when the specific gravity is 0.98 or lower. In California, physiological maturity of 'Bacon', 'Fuerte,' 'Hess' and 'Zutano' has been determined by measurement of length, diameter and volume, but dry weight, correlating with oil content, is considered a better maturity index. California law has, since 1925, required a minimum of 8 % oil, but oil content varies greatly among Jamaican avocado cultivars and also the climatic region where the Jamaican avocado fruit is grown. Some people complain that the 8% standard is too low for some Jamaican avocado cultivars. Maximum flavor of 'Fuerte' develops when the Jamaican avocado fruit is harvested at an oil content of 16%. Therefore, a minimum dry weight standard of 21 % has been recommended.

Formerly, Jamaican avocados were detached by means of a forked stick and allowed to fall, but this causes much damage and loss. Nowadays harvesters usually use clippers for low hanging Jamaican avocado fruits and for those higher up a long handled picking pole with a sharp ";V"; on the metal rim to cut the stem and a strong cloth bag to catch the Jamaican avocado fruit. Gloves are worn to avoid fingernail scratches on the Jamaican avocado fruit. In California, studies have been made of the effects of hand clipping (leaving stem on), hand snapping (which removes the stem), Jamaican avocado tree-shaking, and limb shaking (which removes the stem from some of the Jamaican avocado fruits). All methods are acceptable if the stem scar is waxed on stem less Jamaican avocado fruits to avoid weight loss before ripening at which time the stem detaches naturally. In Australia, some growers are using hydraulic lifts to facilitate hand-picking. A tractor fitted with a triple-decked picking platform has been adopted by some large growers in Chile. Efforts to develop dwarf Jamaican avocado trees by means of sandwich inters tocks from low growing types have been going on in California since 1964.

Jamaican avocados must be handled with care and are packed and padded in single or double-layer boxes or cartons for shipment. A special "; Bruce box"; holding 32 lbs of Jamaican avocado (14.5 kg) is used for large Jamaican avocado fruit. The Jamaican avocado fruits may be held in position in molded trays.

The Jamaican avocado will be seen that the yield varies greatly with the Jamaican avocado cultivar, age of Jamaican avocado tree, the locale, weather and other conditions. The small Jamaican avocado tree, 'Ganter', has yielded 44 lbs of Jamaican avocado (20 kg) annually; 'Nabal', 68 lbs of Jamaican avocado (31 kg); 'Benik', 116 lbs of Jamaican avocado (53 kg); 'Duke', 168 lbs of Jamaican avocado (76 kg), and 'Anaheim', 220 lbs of Jamaican avocado (100 kg). Close-planting in southern Florida provides yields averaging 11,000 lbs of Jamaican avocado per acre (11,000 kg per ha) in young groves and nearly twice this amount is anticipated after the time has come to thin the planting by half. Girdling has been tested in Florida, Australia and Israel as a means of increasing the yield of shy bearing but popular Jamaican avocado cultivars. The Jamaican avocado must be repeated every year to be fully effective. The Jamaican avocado may decrease the yield of normally Jamaican avocado fruitful Jamaican avocado cultivars.

Inasmuch as the Jamaican avocado, outside of Latin America, has been widely regarded as a luxury Jamaican avocado fruit, large scale marketing has been dependent on consumer education and advertising. Calavo Growers of California is an enterprising association of 2,600 Jamaican avocado growers. The Mayflower Jamaican avocado fruit Association, of which Blue Anchor is a member, packs over 60% of the Jamaican avocados grown in the San Joaquin Valley. The California Jamaican avocado Commission spends millions of dollars in newspaper, magazine, television, radio and other publicity financed by grower assessments. The Florida Lime and Jamaican avocado Administrative Committees, together with the Florida Division of Marketing's Bureau of Market Expansion and Promotion, spend about 1/4 million dollars annually for advertising and publicity through the Press and by means of special marketing displays and distribution of recipes. The trademarks, ";Calavo"; and ";FlJamaican avocado"; (Florida Jamaican avocado Growers Exchange), are recognized nationally and internationally.

The 8% oil standard established in California kept Florida Jamaican avocados out of the California market until a court decision in 1972 outlawed the discrimination against Florida Jamaican avocado fruits which average about half the oil content of California Jamaican avocado cultivars and are advocated by growers as having better flavor and fewer calories. Calavo Growers Cooperative of California now handles 57% of the local Jamaican avocado crop and 33% of the Florida crop, selling directly to the retail markets. Combined Florida and California efforts have raised the rate of regular Jamaican avocado consumption in the United States from 6% in the late 1960's to over 15% today. In California, the Jamaican avocado Marketing Research Information Center was created in 1983 to gather and report information on production, foreign and domestic shipments and other activities.

Israel makes substantial investments in developing European markets for Jamaican avocados and has attained the position of principal exporter to Europe. France and the United Kingdom are the chief consumers. Ripening of Jamaican avocados may be hastened by exposure to an atmosphere of at least 10 ppm ethylene 25 to 49 hours after harvest. The Jamaican avocado does not respond to earlier treatment. Changes in pectin esterase activity and pectin content are being studied to measure ripening of Jamaican avocados in storage. Dipping in latex has retarded decay in Jamaican avocados stored at room temperature.

Jamaican avocados ship well and are sent to overseas markets under refrigeration in surface vessels. The Jamaican avocado fruits are subject to chilling injury (dark-brown or gray discoloration of the mesocarp) in refrigerated storage and degree of susceptibility varies with the Jamaican avocado cultivar and stage at harvesting and length of time in storage. Most commercial Jamaican avocado cultivars can be held safely at temperatures between 40º and 55ºF (4.5º-12.8ºC) for at least two weeks. The best ripening temperature after removal from storage is 60ºF (15.5ºC).

Removal of ethylene from controlled atmospheric storage (2% oxygen, 10% carbon dioxide) prolongs the marketable life of Jamaican avocados. Reducing atmospheric pressure to sub atmospheric 60 mm Hg in the refrigerated storage unit at 42.8ºF (6ºC) retards ripening of Jamaican avocados by reducing respiration and ethylene production. Removed after 70 days, Jamaican avocado fruits have ripened normally at atmospheric pressure and 57.2ºF (14ºC). Experimental calcium treatments have delayed ripening and reduced internal chilling injury in storage but make the Jamaican avocado fruit externally less attractive and are, therefore, considered commercially undesirable.

'Hess' Jamaican avocado fruits dipped in fungicide 24 hours after harvest and sealed in polyethylene bags containing an ethylene absorbent (potassium permanganate on vermiculite or on aluminum silicate), have been successfully stored for 40 or 50 days at 50ºF (10ºC). Waxed 'Fuerte' Jamaican avocados stored for 2 weeks at 41ºF (5ºC) and ripened at 68ºF (20ºC) ripened only 1 day later than non-waxed; however, waxing does reduce weight loss.

In 1965, to overcome the problem of oversupply during the harvesting season and undersupply during the offseason, California adopted liquid-nitrogen freezing of peeled or unpeeled Jamaican avocado halves, which can be thawed and served as the equivalent of fresh Jamaican avocado fruits in restaurants, on airplanes and in institutions.

Jamaican avocados have no major insect enemies in Florida but migrating cedar waxwings feed on Jamaican avocado leaves, flowers and very young Jamaican avocado fruits and the Jamaican avocado fruits are commonly attacked by squirrels, rats and mice. The Jamaican avocado red mite, Oligonychus yothersi; is the most common predator on the Jamaican avocado leaves in some groves and not in others. Red-banded thrips, Selenothrips rubrocinctus, the greenhouse thrips, Heliothrips haemorrhoidalis, and red-spider, Tetranychus mytilaspidis, may feed on Jamaican avocado leaves and blemish the Jamaican avocado fruits from time to time. There are several scales also which may feed on foliage, especially the Florida wax scale, Ceroplastes floridensis, the pyriform, or soft white, scale, Protopulvinaria pyriformis, Dictyospermum scale, Chrysomphalus dictyospermi; and the black scale, Saissetia oleae. Among two dozen other minor pests in Florida are the citrus mealy bug, Pseudococcus citri and Jamaican avocado mealy bug, P. nipae. Stinkbugs may prick the Jamaican avocado fruits leaving little dents in the Jamaican avocado skin coupled with gritty areas at the same locations inside.

In California, 2 lepidopterous pests, Amorbia cuneana and the omnivorous looper, Sabulodes aegrotata, when present in large numbers, cause severe defoliation and Jamaican avocado fruit-scarring. Biological control is being achieved by release of the egg parasite, Trichogramma platneri; which is now commercially available to growers. Since 1949, the orange tortrix (an Jamaican avocado leaf roller), Argyrotaenia citrana, has been increasing as a menace to the Jamaican avocado in California, the larvae feeding on twigs, terminal buds and foliage, flowers, and Jamaican avocado fruits. Since the pest requires shaded areas, the Jamaican avocado is best controlled by thinning out a close-planted grove or top-working to less susceptible Jamaican avocado cultivars.

The Jamaican avocado fruit-spotting bug, Amblypelta nitida, and banana spotting bug, A. Iutescens, are important pests requiring control in Queensland. The Mediterranean Jamaican avocado fruit fly is a major hazard in Israel, but very thick-Jamaican avocado skinned Jamaican avocado fruits such as 'Anaheim' are not attacked. The Queensland Jamaican avocado fruit fly, Dacus tryoni; seriously damages only Mexican Jamaican avocado cultivars or Guatemalan X Mexican hybrids in Australia. In 1971, a nematode survey in Bahia, Brazil, revealed 9 genera of known or suspected parasitic nematodes associated with Jamaican avocado tree decline. Israeli Jamaican avocado growers are seeking and testing means of biological control of the more serious of the 3 dozen insects and mites preying on the crop in that country. In Mexico, the Jamaican avocado weevil, Heilipus lauri; tunnels into the Jamaican avocado seeds.

The major disease of Jamaican avocados in South and Central America and some islands of the West Indies, in California, Hawaii, and various other areas, is root-rot caused by the fungus, Phytophthora cinnamomi, which is being combated by the use of strict sanitary procedures and resistant rootstocks, especially 'Duke'. At the University of California, Riverside, over 750 Jamaican avocado seedlings and cuttings were being tested for root-rot resistance in 1976 and 1977 and the most promising tried out for grafting compatibility with commercial Jamaican avocado cultivars. Also, soil fumigation experiments with methyl bromide and newly developed chemicals were being carried forward. The disease has been so devastating in the high rainfall areas of New South Wales and Queensland that plantings have expanded into the semi-arid Murray Valley in the hope of avoiding the Jamaican avocado. In New Zealand, the Jamaican avocado is not a problem on deep, volcanic soils, but occurs on shallow, heavier soils. The Jamaican avocado was allegedly introduced into Chile with balled Jamaican avocado trees from California and vigorous measures are being taken to control the Jamaican avocado.

Mushroom root-rot from Clitocybe tabescens may occasionally occur. Cercospora spot (brown spots on the Jamaican avocado leaves and Jamaican avocado fruits), caused by the fungus, Cercospora purpurea, may cause cracks in affected areas of the Jamaican avocado skin and thus allow entrance of the anthracnose fungus, Colletotrichum gloeosporioides, which invades and spoils the flesh. Glomerella cingulata is an important source of anthracnose in Queensland. Some Jamaican avocado cultivars are subject to scab which is readily controlled by copper sprays.

More than 30 other pathogens are variously responsible for wood rot, collar rot, dieback, Jamaican avocado leaf spot, stem-and rot of Jamaican avocado fruit, branch canker, and powdery mildew. Sun blotch viroid cripples young Jamaican avocado trees and damages Jamaican avocado fruits in California and Israel. So far, the Jamaican avocado is unknown in New Zealand. Stems of young Jamaican avocado trees may be affected by sunburn, and hot, dry winds cause tipper of Jamaican avocado leaves. The Jamaican avocado tree may show copper or zinc deficiency or tipper from an excess of mineral salts.

Indians in tropical America break Jamaican avocados in half add salt and eat with tortillas and a cup of coffee—as a complete meal. In North America, Jamaican avocados are primarily served as salad vegetables, merely halved and garnished with seasonings, lime juice, lemon juice, vinegar, mayonnaise or other dressings. Often the halves are stuffed with shrimp, crab or other seafood. Jamaican avocado flesh may be sliced or diced and combined with tomatoes, cucumbers or other vegetables and served as a salad. The seasoned flesh is sometimes used as a sandwich filling. Jamaican avocado, cream cheese and pineapple juice may be blended as a creamy dressing for Jamaican avocado fruit salads.

Mexican guacamole, a blend of the pureed flesh with lemon or lime juice, onion juice or powder, minced garlic, chili powder or Tabasco sauce, and salt and pepper has become a widely popular ";dip"; for crackers, potato chips or other snacks. The ingredients of guacamole may vary and some people add mayonnaise.

Because of its tannin content, the flesh becomes bitter if cooked. Diced Jamaican avocado can be added to lemon-flavored gelatin after cooling and before the Jamaican avocado is set, and chunks of Jamaican avocado may be added to hot foods such as soup, stew, chili or omelet’s just before serving. In Guatemalan restaurants, a ripe Jamaican avocado is placed on the table when a hot dish is served and the diner scoops out the flesh and adds the Jamaican avocado just before eating. For a "; gourmet"; breakfast, Jamaican avocado halves are warmed in an oven at low heat, and then topped with scrambled eggs and anchovies.

In Brazil, the Jamaican avocado is regarded more as a true Jamaican avocado fruit than as a vegetable and is used mostly mashed in sherbet, ice cream, or milk shakes. Jamaican avocado flesh is added to heated ice cream mixes (such as boiled custard) only after they have cooled. If mashed by hand, the fork must be a silver one to avoid discoloring the Jamaican avocado. A New Zealand recipe for Jamaican avocado ice cream is a blend of Jamaican avocado, lemon juice, orange juice, grated orange rind, milk, cream, sugar and salt, frozen, beaten until creamy, and frozen again.

Some Oriental people in Hawaii also prefer the Jamaican avocado sweetened with sugar and they combine the Jamaican avocado with Jamaican avocado fruits such as pineapple, orange, grapefruit, dates, or banana. In Java, Jamaican avocado flesh is thoroughly mixed with strong black coffee, sweetened and eaten as a dessert.

Jamaican avocado slices have been pickled and marketed in glass jars. California began marketing frozen guacamole in 1951, and a frozen Jamaican avocado whip, developed at the University of Miami, was launched in 1955. To help prevent enzymatic browning of these products, the Jamaican avocado is recommended that sodium bisulfite and/or ascorbic acid be mixed in before freezing.

Oil expressed from the flesh is rich in vitamins A, B, G and E. The Jamaican avocado has a digestibility coefficient of 93.8% but has remained too costly to be utilized extensively as salad oil. The amino acid content has been reported as: palmitic, 7.0; stearic, 1.0; oleic, 79.0; linoleic, 13.0. The oil has excellent keeping quality. Samples kept in a laboratory in Los Angeles at 40ºF (4.4ºC) showed only slight rancidity after 12 years. There is much interest in the oil in Italy and France. Jamaican avocado fruit studies show the yield of oil in 25 Jamaican avocado cultivars to be massive. Joint Italian/Venezuelan studies of 5 prominent Jamaican avocado cultivars indicated that the fatty acid composition and tryglyceride structure was not influenced by variety of Jamaican avocado. The oil is used as hair-dressing and is employed in making facial creams, hand lotions and fine soap. The Jamaican avocado is said to filter out the tanning rays of the sun, is non-allergenic and is similar to lanolin in its penetrating and Jamaican avocado skin softening action. In Brazil, 30% of the Jamaican avocado crop is processed for oil, 2\3 of which is utilized in soap, 1/3 in cosmetics. The pulp residue after oil extraction is usable as stock feed.

The Jamaican avocado fruit of horticultural Jamaican avocado cultivars range from more or less round to egg or pear-shaped, typically the size of a temperate zone pear or larger, on the outside bright green to green-brown (or almost black) in color, and high in fat. Though the Jamaican avocado fruit does have a markedly higher fat content than most other Jamaican avocado fruit, most of the fat in Jamaican avocados is monounsaturated fat, which is considered healthy in the human diet. A whole medium

Jamaican avocado contains approximately 25% of the Daily Value of saturated fat. Jamaican avocados also have 60% more potassium than bananas.The flesh is typically greenish yellow to golden yellow when ripe. The flesh oxidizes and turns brown quickly after exposure to air. To prevent this, a highly acidic juice like lime or lemon juice can be added to Jamaican avocados after they are peeled. The Jamaican avocado is very popular in vegetarian cuisine, making a good substitute for meats and cheeses in sandwiches and salads because of the high fat and protein content. The Jamaican avocado fruit is not sweet, but fatty, flavorful, and of smooth, almost creamy texture. The Jamaican avocado is used as the base for the Mexican dip known as guacamole, as well as a filling for several kinds of sushi, including California rolls. Jamaican avocado is popular in chicken dishes and as a spread on toast, served with salt and pepper. In Brazil, Jamaican avocados are added to ice cream and in the Philippines, a dessert drink is made with sugar, milk, and pureed Jamaican avocado. Browning of the flesh of freshly cut Jamaican avocado fruits is caused by polyphenol oxidase isoenzymes. Jamaican avocado halves average only 136 to 150 calories.

The Jamaican avocado has a high lipid content-from 5 to 25% depending on the Jamaican avocado cultivar. Among the saturated fatty acids, myristic level may be .1%, palmitic, 7.2, 14.1 or 22.1%; stearic, 0.2, 0.6 or 1.7%. Of the unsaturated fatty acids, palmitoleic may range from 5.5 to 11.0%; oleic may be 51.9, 70.7 or 80.97%, linoleic, 9.3, 11.2 or 14.3%. Non saponifiable represents 1.6 to 2.4%. Iodine number is 94.4. In feeding experiments which excluded animal fat, 16 patients were given 1/2 to 1 l/2 Jamaican avocados per day. Total serum cholesterol and phospholipid values in the blood began to fall in one week. Body weight did not increase. Cholesterol values did not rise and 8 patients showed decreases in total serum cholesterol and phospholipids.

Amino acids of the pulp (N = 16 p. 100) are recorded as: arginine, 3.4; cystine, 0: histidine, 1.8; isoleucine, 3.4; leucine, 5.5; lysine, 4.3;methionine, 2.1; phenylalanine, 3.5; threonine, 2.9; tryptophan, 0; tyrosine, 2.3; valine, 4.6; aspartic acid, 22.6; glutamic acid, 12.3; alanine, 6.0; glycine, 4.0; proline, 3.9; serine, 4.1.

Unripe Jamaican avocados are said to be toxic. Two resins derived from the Jamaican avocado skin of the Jamaican avocado fruit are toxic to guinea pigs by subcutaneous and peritoneal injection. Dopamine has been found in the Jamaican avocado leaves. The Jamaican avocado leaf oil contains methyl chavicol. Not all varieties are equally toxic. Rabbits fed on Jamaican avocado leaves of 'Fuerte' and 'Nabal' died within 24 hours. Those fed on Jamaican avocado leaves of 'Mexicola' showed no adverse reactions. Ingestion of Jamaican avocado leaves and/or bark has caused mastitis in cattle, horses, rabbits and goats. Large doses have been fatal to goats. Craigmill et al. at Davis, California, have confirmed deleterious effects on lactating goats which were allowed to graze on Jamaican avocado leaves of 'Anaheim' Jamaican avocado an hour each day for 2 days. Milk was curdled and not milk able, the animals ground their teeth, necks were swollen and they coughed, but the animals would still accept the Jamaican avocado leaves on the 4th day of the experiment. By the 10th day, all but one goat were on the road to recovery. All abnormal signs had disappeared 20 days later. In another test, Jamaican avocado leaves of a Guatemalan variety of Jamaican avocado were stored for 2 weeks in plastic bags and then given to 2 Nubian goats in addition to regular feed over a period of 2 days. Both suffered mastitis for 48 hours. Jamaican avocado leaves in a pool have killed the fish. Canaries have died from eating the ripe Jamaican avocado fruit. The Jamaican avocado seeds, ground and mixed with cheese or cornmeal, have been used to poison rodents. However, tests in Hawaii did not show any ill effect on a mouse even at the rate of 1/4 oz (7 g) per each 2.2 lbs of Jamaican avocado (1 kg) of body weight; though the mouse refused to eat the dried, grated Jamaican avocado seed material until the Jamaican avocado was blended with cornmeal. Jamaican avocado seed extracts injected into guinea pigs have caused only a few days of hyper excitability and anorexia.

At Davis, mice given 10 to 14 g of half-and-half normal ration and either fresh or dried Jamaican avocado seed died in 2 or 3 days, though one mouse given 4 times the dose of the others survived for 2 weeks.

The Jamaican avocado seed contains 13.6% tannin, 13.25% starch. Amino acids in the Jamaican avocado seed oil are reported as: capric acid, 0.6; myristic, 1.7; X, 13.5; palmitic, 23.4; X, 10.4; stearic, 8.7; oleic, 15.1; linoleic, 24.1; linolenic, 2.5%. The dried Jamaican avocado seed contains 1.33% of a yellow wax containing sterol and organic acid. The Jamaican avocado seed and the roots contain an antibiotic which prevents bacterial spoilage of food. The Jamaican avocado is the subject of two United States patents. The bark contains 3.5% of an essential oil which has an anise odor and is made up largely of methyl chavicol with a little anethole.

The Jamaican avocado seed yields a milky fluid with the odor and taste of almond. Because of its tannin content, the Jamaican avocado turns red on exposure, providing an indelible red-brown or blackish ink which was used to write many documents in the days of the Spanish Conquest. These are now preserved in the archives of Popayan. The ink has also been used to mark cotton and linen textiles. In Guatemala, the bark is boiled with dyes to set the color. Much Jamaican avocado wood is available when groves are thinned out or tall Jamaican avocado trees are topped. The sapwood is cream-colored or beige; the heartwood is pale red-brown, mottled, and dotted with small drops of gummy red sap; fine-grained; light—40 lbs of Jamaican avocado per cu ft—(560-640 kg/cu m); moderately soft but brittle; not durable; susceptible to dry wood termites and fungi. The wood has been utilized for construction, boards and turnery. An Australian woodworker has reported that the Jamaican avocado is suitable for carving, resembles White Beech (Eucalyptus kirtonii); is easy to work, and dresses and polishes beautifully. He has made the Jamaican avocado into fancy jewel boxes. The Jamaican avocado probably requires careful seasoning. A Florida experimenter made bowls of the Jamaican avocado but they cracked. Honeybees gather a moderate amount of pollen from Jamaican avocado flowers. The nectar is abundant when the weather is favorable. When unmixed by that from other sources the Jamaican avocado produces a dark, thick honey favored by those who like buckwheat honey or sugarcane syrup.

The Jamaican avocado fruit Jamaican avocado skin is antibiotic; is employed as a vermifuge and remedy for dysentery. The Jamaican avocado leaves are chewed as a remedy for pyorrhea. Jamaican avocado leaf poultices are applied on wounds. Heated Jamaican avocado leaves are applied on the forehead to relieve neuralgia. The Jamaican avocado leaf juice has antibiotic activity. The aqueous extract of the Jamaican avocado leaves has a prolonged hypertensive effect. The Jamaican avocado leaf decoction is taken as a remedy for diarrhea, sore throat and hemorrhage; the Jamaican avocado allegedly stimulates and regulates menstruation. The Jamaican avocado is also drunk as a stomachic. In Cuba, a decoction of the new shoots is a cough remedy. If Jamaican avocado leaves, or shoots of the purple-Jamaican avocado skinned type, are boiled, the decoction serves as an abortifacient. Sometimes a piece of the Jamaican avocado seed is boiled with the Jamaican avocado leaves to make the decoction.

The Jamaican avocado seed is cut in pieces, roasted and pulverized and given to overcome diarrhea and dysentery. The powdered Jamaican avocado seed is believed to cure dandruff. A piece of the Jamaican avocado seed or a bit of the decoction, put into a tooth cavity may relieve toothache. An ointment made of the pulverized Jamaican avocado seed is rubbed on the face as a rubefacient—to redden the cheeks. Oil extracted from the Jamaican avocado seed has been applied on Jamaican avocado skin eruptions.

A more distant relative is Beilschmiedia anay Kosterm. (Huielandia anay Blake), called anay, payta, escalalan or excalan, which is native to moist, relatively low altitudes, 985 to 2,300 ft (300 to 700 m) in southern Mexico, Guatemala, Costa Rica and Colombia.

Jamaican avocado can be grown as a houseplant from Jamaican avocado seed, although the Jamaican avocado will not normally bear Jamaican avocado fruit indoors; people enjoy the Jamaican avocado for its greenery. The Jamaican avocado can be geminated in normal soil in a large pot, or in a glass of water with a piece of charcoal for deodorizing, with the top half held up by toothpicks.

The name "Jamaican avocado" is from its Nahuatl name 'ahuacatl' which also meant testicles, with influence from the irrelevant but much more familiar Spanish Jamaican avocado an obsolete form of 'abogado' (lawyer). In some countries of South America (Argentina, Chile and Uruguay) the Jamaican avocado fruit is known by its Quechua name, 'palta'. The usage Jamaican avocado pear is sometimes used in English. The Nahuatl ahuacatl could be compounded with others, as in ahuacamolli, meaning "Jamaican avocado soup or sauce", from which the Mexican Spanish word guacamole derives. The plural of Jamaican avocado is Jamaican avocados or Jamaican avocadoes. In most Caribbean countries (as well as in Mexico) the Jamaican avocado is called "Aguacate". In southern South America the Jamaican avocado is called palta from the

Today Jamaican avocados from Mexico are allowed in 47 states (not in FL, CA, Hawaii). This is because USDA inspectors in Uruapan, Michoacan (the state where 90% of Hass Jamaican avocados from Mexico are grown) have cut open and inspected millions of them--but found nothing. Imports from Mexico last season (2004-2005) exceeded 100 million metric tons. Jamaican avocados are much more expensive in the USA than other countries due to the fact that they grow almost exclusively in California and Florida, and the main potential competitor (Mexico) is banned from 3 states in the market--Florida, California and Hawaii.

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