|Citrus sinensis subsp. var.||Orange|
An orange—specifically, the sweet orange—is the citrus fruit Citrus sinensis (syn. Citrus aurantium L. var. dulcis L., or Citrus aurantium Risso) and its fruit. The orange is a hybrid of ancient cultivated origin, possibly between pomelo (Citrus maxima) and tangerine (Citrus reticulata). It is a small flowering tree growing to about 10 m tall with evergreen leaves, which are arranged alternately, of ovate shape with crenulate margins and 4–10 cm long. The orange fruit is a hesperidium, a type of berry.
Oranges originated in Southeast Asia. The fruit of Citrus sinensis is called sweet orange to distinguish it from Citrus aurantium, the bitter orange. In a number of languages, it is known as a "Chinese apple" (e.g. Dutch Sinaasappel, "China's apple", or "Apfelsine" in German). The name is thought to ultimately derive from the Dravidian word for the orange tree, with its final form developing after passing through numerous intermediate languages.
All citrus trees are of the single genus Citrus, and remain largely interbreedable; that is, there is only one "superspecies" which includes grapefruits, lemons, limes and oranges. Nevertheless, names have been given to the various members of the genus, oranges often being referred to as Citrus sinensis and Citrus aurantium. Fruits of all members of the genus Citrus are considered berries because they have many seeds, are fleshy and soft, and derive from a single ovary. An orange seed is called a pip. The white thread-like material, attached to the inside of the peel is called pith.
The Persian orange, grown widely in southern Europe after its introduction to Italy in the 11th century, was bitter. Sweet oranges brought to Europe in the 15th century from India by Portuguese traders, quickly displaced the bitter, and are now the most common variety of orange cultivated. The sweet orange will grow to different sizes and colours according to local conditions, most commonly with ten carpels, or segments, inside.
Some South East European tongues name orange after Portugal, which was formerly the main source of imports of sweet oranges. Examples are Bulgarian portokal [портокал], Greek portokali [πορτοκάλι], Romanian portocală and Georgian phortokhali [ფორთოხალი]. Also in South Italian dialects (Neapolitan), orange is named portogallo or purtualle, literally "the Portuguese ones". Related names can also be found in non-European languages: Turkish Portakal, Arabic al-burtuqal [البرتقال], Persian porteghal [پرتقال] and Amharic birtukan.
Portuguese, Spanish, Arab, and Dutch sailors planted citrus trees along trade routes to prevent scurvy. On his second voyage in 1493, Christopher Columbus brought the seeds of oranges, lemons and citrons to Haiti and the Caribbean. They were introduced in Florida (along with lemons) in 1513 by Spanish explorer Juan Ponce de Leon, and were introduced to Hawaii in 1792.
A single mutation in 1820 in an orchard of sweet oranges planted at a monastery in Brazil yielded the navel orange, also known as the Washington, Riverside, or Bahie navel. The mutation causes navel oranges to develop a second orange at the base of the original fruit, opposite the stem. The second orange develops as a conjoined twin in a set of smaller segments embedded within the peel of the larger orange. From the outside, the smaller, and undeveloped twin leaves a formation at the bottom of the fruit that looks similar to the human navel.
Because the mutation left the fruit seedless and, therefore, sterile, the only means available to cultivate more of this new variety is to graft cuttings onto other varieties of citrus tree. Two such cuttings of the original tree were transplanted to Riverside, California in 1870, which eventually led to worldwide popularity.
Today, navel oranges continue to be produced via cutting and grafting. This does not allow for the usual selective breeding methodologies, and so not only do the navel oranges of today have exactly the same genetic makeup as the original tree, and are therefore clones; in a sense, all navel oranges can be considered to be the fruit of that single, over a century-old tree.
On rare occasions, however, further mutations can lead to new varieties.
The Valencia or Murcia orange is one of the sweet oranges used for juice extraction. It is a late-season fruit, and therefore a popular variety when the navel oranges are out of season. For this reason, the orange was chosen to be the official mascot of the 1982 FIFA World Cup, which was held in Spain. The mascot was called "Naranjito" ("little orange"), and wore the colours of the Spanish soccer team uniform.
The blood orange has streaks of red in the fruit, and the juice is often a dark burgundy colour. The fruit has found a niche as an interesting ingredient variation on traditional Seville marmalade, with its striking red streaks and distinct flavour. The scarlet navel is a variety with the same diploid mutation as the navel orange.
Grafting, cuttings for true offspring. Seed.
Pests and diseases
Fruit, juice, marmelade. Oil from peel. Orange peel is used by gardeners as a slug repellent. Orange leaves can be boiled to make tea.
Satsuma Oranges picked on Christmas day 2007 in Gainesville, Florida
Standard Cyclopedia of Horticulture
|Standard Cyclopedia of Horticulture|
Orange. Plate LXXVIII. The orange is one of the oldest of cultivated fruits. Its nativity is still in doubt, but it is probable that it is indigenous to the Indo- Chinese region. It is now widely distributed in all warm- temperate and tropical countries, in many of which it has run wild and behaves like a native plant. In parts of Florida the orange was found wild when permanent settlements were made, but it had probably spread from stock that was introduced by the early Spaniards. In stature of tree and character of fruit, the orange has varied immensely. Normally, the fruit contains ten compartments or locules; but under the influence of domestication these compartments have been increased, and in some cases a secondary axis, with its accompanying locules, has been thrust into the center of the fruit, causing the "navel" appearance of some varieties (Figs. 2611, 2612). These navel oranges, of which the Washington Navel, or Bahia, is the best known, are chance kinds or varieties, as other varieties are. The immediate cause of this particular kind of variation, as of other variations, is unknown. The Washington Navel was introduced from Brazil in 1870 by the late Wm. Saunders, and by him distributed as the Bahia (see Van Deman, Report of the Department of Agriculture, 1886, page 267). The two "original" trees in California are still standing at Riverside, carefully protected (Fig. 2613). In recent years, some of the odd and grotesque types of Japanese oranges have been introduced into this country, but they will probably always be curiosities rather than commercial pomological products. See A.G. 1890,333-336. The sweet and sour oranges are considered to be two species (pages 782-784, Volume II), Citrus sinensis and C. Aurantium respectively. To the former belong nearly all the usual commercial oranges, although the King orange is C. nobilis, of which the tangerines, mandarins and satsumas are varieties (Figs. 2614, 2615). The orange belongs to a tribe of three-foliolate plants, and although its leaves appear to be simple, they are really compound. Fig. 2616 shows the articulation above a, at which point the blade is jointed to the rachis; this blade is a leaflet, and the side leaflets have not developed, as they do in the tri- foliolate orange (Citrus, or Poncirus, trifoliata).
There are three well-developed orange regions within the confines of the United States: central and southern Florida; the delta region of the Mississippi; California. Parts of Texas and the Mexico-Arizona region will no doubt develop into commercial orange sections in the near future. Until within recent years a large part of the oranges consumed in this country had come from Mediterranean regions, but the Florida and California oranges have taken the place of the imported fruit.
Oranges under glass.
Years ago, oranges were commonly grown under glass in England and parts of the continent. At that time there was no rapid transportation between the orange-growing regions and northern countries, and the orange fruit was a luxury. Special houses, known as "orangeries," were devoted to the culture of the fruit. The trees were ordinarily grown in large tubs or boxes, and were kept in the open in summer and were placed in the orangery in winter. These orangeries were scarcely greenhouses in the modern understanding of the term. In many cases they had slate or shingle roofs, the sides only being provided with an extra extent of glass in the shape of windows. Some of them, however, were houses with glass roofs. As imported oranges came to be more common, these orange-houses gradually fell into disuse. It is doubtful whether there are any of these establishments now standing in this country; but one sees them sometimes in Europe. As the orange trees disappeared, other plants were grown in the house, so that an orangery came to mean a particular kind of house in which plants are grown that will thrive in conditions suited to the orange. It came to be no uncommon thing to see orangeries in which there were no oranges.
The orange tree is still a popular subject in conservatories, however, and in window-gardens. In the latter conditions it rarely produces fruit of any consequence, but the shining evergreen foliage and the very fragrant flowers make the plant interesting and desirable. The plant is subject to scale and mealy-bug, and constant attention must be given to syringing and sponging the foliage. The leading difficulty in the rearing of an orange tree in the dwelling-house is a tendency to have it growing the entire year and to keep it too wet at the roots. After the fruiting season, in late autumn or early winter, the plant should be allowed to rest for a time in order to harden its wood for the next year's bloom. It may then be kept at a temperature of 40° to 50° and fairly dry at the roots. Water should not be withheld entirely, however, because the plant should be kept in such condition that the foliage will not drop. After a period of relative inactivity of one or two months, the plant may be set in a sunny place and given a somewhat higher temperature, and water and liquid manure may be applied at the roots. It should be in bloom in the summer and early autumn. Best results are secured if the roots are somewhat confined. When the plant is small, it may be potted on from time to time; but after it has attained the height of 5 or 6 feet, it should not be given more root-room than a small tub or a half-barrel. Ordinarily, it will not need repotting for several years at a time after it has attained this size. Some of the surface soil may be removed from time to time and fresh soil added and liquid manure applied. Usually the plants are grown from seeds, and they vary as peaches or apples do. Some of the plants may give desirable fruit, but the larger part of them will give fruit of indifferent or even inferior quality. If the best kind of fruit is wanted, the young plants should be budded after they are well established in the pots. Buds may be secured from any tree that bears a desirable fruit, or they may be brought from the South.
In recent years the Otaheite orange (described in Volume II, page 78.5) has come into prominence as a pot-plant. It is known botanically as Citrus taitensis (Fig. 2617). It is undoubtedly the best form of orange for growing in the house. The fruits are small and handsome, and the flowers have a pinkish tinge and are very fragrant. These plants will bloom and bear when not more than a foot high if the roots are somewhat confined or the plants not over-potted. Usually they will bloom the greater part of the year, but, like most hard-wooded plants, the best results are secured if they have a period of rest, as indicated above. The temperature for all oranges should be relatively low; that is, it should be the temperature of the intermediate house or one that will grow carnations, chrysanthemums, geraniums, and the like.
There is much literature on the orange, a large part of it in the form of bulletins and reports. An authoritative general work on oranges is Risso and Poiteau, "Histoire et Culture des Oranges," Paris. On the oriental forms and histories of oranges, one should consult Bonavia, "The Cultivated Oranges and Lemons of India and Ceylon," London, 1890. The American books on the orange are as follows: Hume "Citrus Fruits and Their Culture;" Coit, "Citrus Fruits;" Garey, "Orange Culture in California;" Moore, "Treatise of Orange Culture in Florida, Louisiana and California;" Manville, "Practical Orange Culture: including the Culture of the Orange, Lemon, Lime, and other citrous fruits as grown in Florida;" Spalding, "The Orange: Its Culture in California;" also small books or pamphlets or reports LXXVIII. A cluster of oranges—the Pineapple variety. by Canada, Davis, Fish, Fowler, Gallesio, Garcelon, Lelong, Prange. L. H. B.
Orange-culture in Florida.
The Spanish occupation of Florida began with the landing of Ponce de Leon in 1513, and they maintained a more or less precarious hold upon the state, disputing possession with the English colonists to the northward, and with the aborigines, until the year 1821 (excepting the years 1763-1783), when it passed under the control of the United States. It was during the Spanish r6gime that oranges were first grown in Florida, and there is reason to believe that as early as the year 1600 the orange was fairly well established on the Florida peninsula.
As in the early days of orange-culture in Spain, the sour orange (Citrus Aurantium) was the fruit cultivated, so in Florida it is not unlikely that the earliest Spanish importations were of sour orange fruit from which seed was secured. At any rate, when the early English colonists made their homes in Florida, they found the sour orange much the more common, although some sweet orange groves were also found. One of the most noteworthy of these sweet orange groves was found in 1823 in Turnbull Hammock near Hawk's Park. It was from this grove that the old strains of oranges which made the Indian River famous came. The old sour orange groves were found mainly on the shores of lakes and rivers, where the fruit had been brought and consumed by the Indians and where the seeds, thrown aside by them, found a congenial soil for germination and growth. The trees were usually mixed with and protected by magnolia, live oak, and other hardwood forest growth. These natural sour orange groves were the foundation, in many instances, of important sweet orange plantings, particularly in the older orange districts in the central part of the state. In some cases, the sour orange trees were topworked where they stood; in others they were taken up, planted out in orchard form and then topworked. There is no orchard cultivation of the sour orange in the state at this time.
The earlier sweet orange groves in Florida were established near lakes and rivers because these afforded the only means of getting the fruit to market. These plantings were made almost entirely with seedling trees, and in spite of the ravages of mal-di-gomma and frost, in many regions they furnish a very large proportion of the crop at the present time. Nor is its quality open to question. In the early sixties there were many famous groves along the St. John's River, but it was not until the railroads opened up the state that the growing of citrous fruits took its place as Florida's most important horticultural industry.
Previous to the severe frost of 1894-5, much fruit was produced in northern Florida, but while some is still grown, the industry has been gradually moving southward, until now the larger part of the total crop comes from the southern part of the state.
The Florida climate is usually marked in spring by a pronounced dry period which extends from the latter part of March or early April up to the beginning of the summer rains, which generally commence in June. During June, July, and August, the rainfall is uniform and heavy. The autumn months are fairly dry, while showers are intermittent during the winter season, with a very large proportion of days of bright sunshine. The annual average rainfall is 53 inches, most of which comes during the summer months.
Florida has been visited from time to time by severe cold waves. Among these, the most noteworthy were the ones which came in 1886 and in 1894-5. At the time of these cold waves, the orange industry was established in the more northerly counties of the state and consequently the damage was much more serious than would occur at the present time, owing to the opening up of the southern districts. The damage from cold waves in Florida has often been greatly increased because they were preceded by periods of high temperatures which caused sap movement in the trees. When entirely dormant, an orange tree is fairly hardy, while, in growth or when stirred from its dormant condition, it may be injured at comparatively high temperatures. This, however, is more or less true of other plants, though they do not respond so readily to variations in temperature. But in Florida, many fruit- trees and ornamentals entirely hardy much farther north have been injured at times because they were not completely dormant.
Florida lands are generally grouped according to elevation and the growth of native timber or vegetation by which they are, or were, covered in a virgin state. Those commonly used for the cultivation of citrous fruits are high hammock, and low hammock, high pine and flat woods land. High hammock lands are elevated, naturally well drained, and are covered with a native growth of evergreen hardwood and deciduous trees. Among these may be mentioned the live oak, hickory, magnolia, dogwood, and holly. They arc well supplied with vegetable matter, the soil is comparatively rich, deep and well adapted for citrous fruit-culture.
Low hammock lands (hammock is an Indian name for a hardwood forest) correspond in a large measure to the high hammock soils. They are not so well drained naturally. The native growth is of much the same character, but the sweet gum, live oak, and cabbage palmetto are more in evidence. Drainage requires careful attention, but the soil is rich in humus. The clearing and preparation of these low hammocks for planting is difficult and expensive, but the results in vigorous orange trees and crops of tine fruit leave Little to be desired.
High pine land is well drained, elevated and often rolling. The native growth consists almost entirely of long-leaf or yellow pine with little or no undergrowth, the latter being replaced by wire-grass. Sometimes a few high-land willow oaks are found. These lands are frequently swept by fires, and consequently the humus- content is lower than would otherwise be the case. The subsoil may be sand, clay or loamy sand. They are not rich soils, but respond readily to good treatment and produce excellent oranges.
Flat woods land is also covered with long-leaf and other pines, but the elevation is much lower and the surface flat and level. Often there is a dense growth of saw palmetto. The subsoil may be clay, sand or hardpan. The better class of flat woods make good citrous soils, but those supporting a heavy growth of saw palmetto or with a hardpan subsoil are not considered good, and though sometimes used are usually avoided. In the handling of Florida soils, the most important things to which attention should be given are drainage and the maintenance of the humus-content of the soil. The rainfall is heavy at times and provision must be made for the rapid elimination of surplus moisture, while the light character of the soil, high temperatures and moist condition assist in the rapid disintegration of the vegetable matter. A water table about 3 feet below the surface is desirable.
Stocks for citrous trees.
Intimately associated with the character of the soil is the kind of stock which should be used for the orchard. The seedling sweet orange as a foundation for a young orchard is a thing of the past and at this time only trees budded on stocks of different kinds are used.
The stocks more or less commonly used for orange trees in Florida are sour orange (Citrus Aurantium), rough lemon (form of Citrus Limonia), grapefruit (Citrus grandis) and trifoliata (Poncirus trifoliata). Each has its peculiar advantages for certain soils and climatic conditions.
No stock is more commonly used in the world's citrous regions than the sour orange. Trees propagated on it are long- lived, vigorous, and produce fruit of high quality. The stock itself is resistant to mal- di-gomma and some other similar diseases which affect other stocks. Wherever it can be used, it should be given preference. It is a congenial stock for all important varieties of oranges, the Satsuma alone excepted. This variety does not grow well upon it. The sour orange tree itself is more resistant to cold than the sweet oranges usually worked on it. It is adapted to low hammock, high hammock, flat woods and to high pine land soils where the latter are not too porous, open, and deficient in moisture. If fruit is to be held on the trees later than its season, or for late-maturing varieties, it has no superior.
Rough lemon stock produces more vigorous tree- growth than sour orange stock. The root-system is widespreading and rather shallow. It is much more tender than the sour orange and trees budded on it are not so cold-resistant. It is not desirable for early varieties as the fruit is not well filled and juicy, and fruit borne by trees budded on it cannot be held very much beyond its season without parting with its juice. It is adapted to conditions where a comparatively shallow root-system is advantageous and to very light sandy soils where a root-system of wide foraging range is necessary.
Grapefruit stock, used in a limited way, produces high quality fruit and is adapted to soils containing liberal amounts of moisture and with rather high water-tables. Where it can be used, it gives very satisfactory results. If the soil is underlaid with clay, close to the surface, so much the better. Grapefruit stock is entirely unsuited to dry open porous soils. In point of hardiness and resistance to cold, it ranks with rough lemon.
Poncirus (Citrus) trifoliata, commonly referred to as trifoliata stock, is the hardiest citrous stock now in general use in America. The tree itself will stand 22° F. at least and it imparts a certain measure of its own hardiness to the orange that is worked on it. This, in the main, is brought about by its very dormant character. In this combination is a noteworthy example of an evergreen tree budded on a deciduous one. Trees budded upon it do not start into growth so readily nor so early in spring. The fruit produced on this stock is smooth, thin-skinned, very juicy, and of high quality even with the very first crops. Poncirus trifoliata stock is adapted to clay soils, loamy or sandy soils with clay close to the surface and to alluvial soils. It requires a uniform and goodly supply of moisture. In Florida it is used for plantings of Satsuma and other oranges in the northern and western parts of the state.
Propagation and the seed-bed.
The seed-bed in which citrous seedlings are grown is carefully prepared in advance by liming and by applying commercial fertilizers. The soil is well and deeply broken, pulverized and raked free of all roots and trash. Irrigation is usually provided, though not always necessary and may be dispensed with on moister soils.
Seeds of sour orange, rough lemon, grapefruit and trifoliata are extracted by cutting through the rind of the fruit, twisting the halves apart and squeezing out the pulp and seed into a vessel. They are then washed free from pulp and dried off slightly in the sun, just enough to remove such moisture as may remain on the seed-coats. Sometimes the fruits are allowed to decay partially, when the seed is removed by macerating in water and floating off the pulp, rind, and other refuse.
Citrous seeds will not stand drying and remain viable. If they are dried, the cotyledons separate and they will not germinate. Seeds may be kept several weeks, or even months, by drying off on the outside and packing in pulverized charcoal in tight receptacles. It is best, however, to plant sour orange, rough lemon, and grapefruit seeds immediately after they are extracted in December and January. Trifoliata seed is best extracted in September and October and planted at once in soil containing considerable moisture, yet well drained. Frosts arc very injurious to young citrous seedlings of all kinds except trifoliata. If frozen off when 1 or 2 inches in height, they are killed out, but trifoliata develops shoots from buds lower down on the stem and the stand is but little injured.
Seeds are planted much as garden beans are planted, in rows 2 feet apart. Frequent cultivation is given from the time the plants come through the soil, and fertilizers rich in nitrogen are applied from time to time as required by the seedlings. Damping-off sometimes causes serious losses in seed-beds, but may be prevented by spraying frequently with bordeaux mixture and by keeping the soil about the plantlets dry and well pulverized on top.
Seedlings are transplanted when one year old and 6 to 15 inches in height or when two years old and 15 to 24 inches in height. Preference is given to the larger seedlings, as they are easier to handle and care for under field conditions. The nursery rows are spaced 4 feet apart, the plants about 1 foot apart in the rows. A row is left out here and there at convenient distances apart, making an 8-foot wagon passage. About 10,000 seedlings are set on an acre of ground.
The seedlings are grown from one to two seasons in the nursery, when they are ready for budding. While citrous trees may be propagated in many different ways, budding alone is resorted to in nursery practice in Florida. By far the greater number of trees are dormant budded, the buds being inserted by the ordinary inverted shield method, the cross cuts being made at the bottom of the downward incisions and the buds shoved up from below. Wrapping is usually done with strips of waxed cloth. These are allowed to remain on from ten days to three weeks, depending upon weather conditions. Frequently, in the colder sections, these dormant buds are banked with earth, using a plow and a celery-hiller, to protect them against possible frost- injury in winter. In spring, the seedling tops are cut off and a stake driven beside each bud, to which it is tied as it grows. These stakes (4 feet long and ¾ inch square, made of cypress) insure straight trunks on the young trees and prevent the buds from being broken off when young and succulent. Careful attention is given to keep off all sprouts which come out on the stock and on the bud growth too low down. The work of sprouting and tying requires each bud to be handled five or six times by competent workmen, during the summer growing season. This adds greatly to the expense, but is necessary in the production of quality stock. At about 30 inches, the buds are topped and allowed to branch. Good buds of one season s growth will caliper ½ to ⅞ inch, 2 inches above where the buds were inserted. Usually the buds are placed rather close to the ground.
One-year buds are used by many planters, but two- and three-year buds are preferred by many, particularly among the older planters. These hitter trees caliper from 1 to 2 inches, depending upon the variety and the stock on which they are grown.
Opinions vary considerably as to the best distances at which to set orange trees in Florida, but 25 by 25 feet may be taken as a reasonable distance for standard sorts, or sixty-nine trees to the acre. Some prefer to set trees farther apart one way than the other, as 20 by 30 feet. Satsuma is usually planted 20 by 20 feet. The rectangular system is used almost entirely.
Land is prepared for planting, by plowing deeply and pulverizing thoroughly. Nearly all Florida soils are greatly benefited by applications of lime, and by having a cover-crop of some kind grown on them during the summer and turned under the autumn before planting. This increases the humus-content of the soil and leaves it in the best possible condition for the trees.
Sometimes orange trees are planted out during the early summer months, just after the summer rains set in; but by far the best season for planting the trees is during the winter months of December, January, and February. Planting should not be delayed too late; as best results are secured if the trees are established in advance of the dry spring period, which usually begins in March.
In the actual setting of the trees, the chief points to be observed are (1) that the roots be not exposed, (2) that the trees be set at the same depth as they grew in the nursery row, (3) that the soil, naturally rather open, be well packed and firmed about the roots. Balled trees are not used in Florida on account of the character of the soil, nor are they considered necessary. Water at time of planting is advantageous, as it helps to settle and pack the soil about the roots, and at times there is an actual lack of moisture to be supplied. Surface soil is used in filling in about the roots and some commercial fertilizer is often thoroughly mixed with it, from a half-pound to a pound, depending upon the size of the trees. The use of stable manure is not advisable.
Clean cultivation throughout the year, though at one time attempted in Florida, is a practice which has entirely disappeared. It did not take many years to demonstrate that it was a failure, because the basic necessity of maintaining and increasing the humus- content of the soil was not taken into consideration. At the present time, two systems of cultivation are in use: (1) the usual system of clean cultivation in spring and summer, followed by a cover-crop; (2) a system of non-cultivation, under which the vegetation which covers the soil is cut from time to time and allowed to mulch the surface.
By far the greater number of plantings is handled by the first system. Under the clean-culture-cover- crop or the 4-C system, cultivation begins in early spring as soon as danger of frost is past and the trees have started into growth, and is continued until about the middle of June or the beginning of the summer rainy season. During this period the grove is cultivated shallowly once every ten days or thereabouts, and a dust mulch is constantly preserved to prevent the escape of moisture from the soil. When cultivation ceases in June, a cover-crop is either planted or allowed to come on voluntarily, consisting of cowpeas, velvet beans, beggarweed or native weeds and grasses. If the growth of this crop is so rank as to make it difficult to handle in fall, it is cut with a mowing machine and allowed to remain on the ground for some time before incorporating in the soil. In autumn the coyer-crop is either plowed under or cut into the soil with a disc-harrow. It is advisable to have the ground bare and free from vegetation in winter as a safeguard against fires, and when the soil is bare, the trees suffer much less from cold than when the soil surrounding them is covered by a dense mat of dead or living vegetation. On heavier soils the cover-crop may be plowed under, but on lighter soils best results are secured by disposing of it with disc-harrow, cutting it over several times if necessary. In Florida, it is not advisable to incorporate a green cover-crop with the soil. The advantage of the 4-C system is that clean culture during the spring months conserves soil-moisture when most needed, while the cover-crop during the summer helps to take care of the excess supplied by the rains. At the same time, vegetable matter is added. In handling young groves, the plan is often followed of cultivating the soil in the narrow strip along the tree rows throughout practically the whole season and growing a cover- crop on the middles. The implements commonly used for grove-cultivation in Florida are the plow, disc-harrow, and Acme harrow.
The system of non-cultivation is followed on certain lowlands, on light soils, and, in general, where the character of the soil or subsoil makes it inadvisable to follow the 4-C system. It has also given good results under conditions where the 4-C system might be used, and is followed because less expensive and the trees thrive under it. The plan is to give no cultivation at all, except when the trees are young, only to hoe the weeds and grass immediately surrounding the trees. This same end is secured in many cases by mulching heavily with weeds, grass, leaves or trash of any sort. From time to time, the mower is used to cut down the growth of vegetation. It is allowed to remain where it falls. There is no question but that fine fruit is produced under certain conditions by this system, but much depends upon the character of the soil and the moisture available.
The plants commonly used in Florida for cover-crops are beggarweed, cowpeas, velvet bean and its relatives, and native weeds and grasses. Cowpeas and velvet beans are better adapted for new soils, those only recently brought into cultivation. These crops are also very valuable for preparing soils for planting. A good stand of cowpeas may be secured on almost any Florida citrous soil if planted at the right season. But the best cover-crop for Florida orange groves is beggar- weed, either alone or combined, as it most usually is, with a number of other native plants. These latter appear without the necessity of seeding them.
Beggarweed is a strong, erect annual legume, a native of Florida, and thoroughly adapted to all parts of the state. When standing apart, with plenty of room for growth, it is a much-branched plant, but, when closely planted, it produces small straight stems. Nitrogen tubercles are produced in abundance on its deep roots. At the end of its season's growth, a good covering of partially decayed foliage covers the ground. Often it is best to cut it once during the season to prevent its getting too rank and heavy. If cut at the blossoming season, a second crop will come on from the stubble. As much as one to two tons of stems and leaves may be produced to an acre. From five to ten pounds of seed are sown to the acre in April and May, broadcasted and harrowed into the soil. After the crop has become well established, it reseeds itself from year to year and cultivation may be continued up to the rainy season without interfering with the crop. It will come on as soon as cultivation ceases. If it be deemed advisable to stop the growth of beggarweed in a grove, as is sometimes the case if there is too much nitrogen in the soil, it may be accomplished by cutting frequently to prevent seeding and by continuing cultivation later into the summer.
The general plan followed in Florida orange-growing is to give the trees but little pruning. Beyond shaping up the trees, mostly done while they are young, little is done except to remove dead, injured or diseased branches. The type of trees developed is low-headed, symmetrical, and spreading. The low-headed tree is almost the only form seen in the younger groves and as the advantages in shading the ground and the tree-trunks, in spraying and in harvesting, are all in its favor, it is not likely to be displaced.
In no citrous region have the problems connected with the fertilizing of orange groves received more attention nor has a greater amount of definite knowledge pertaining to this difficult problem been secured than in Florida. The kind and quantity of fertilizer used has a pronounced influence, not only upon the quantity and quality of fruit, but upon the growth, health and longevity of the trees, and it has taken many years to determine the value of different materials in the fertilizers applied. Much remains to be found out, but a good start has at least been made.
The leguminous cover-crops referred to, when rightly handled, supply a large part of the necessary nitrogen, but the fertilizers applied to orange groves in Florida are drawn almost entirely from commercial sources. Potash is used largely in the forms of high- and low- grade sulfate of potash; phosphoric acid is secured from bones and phosphate rock, while nitrogen is procured from nitrate of soda, sulfate of ammonia, and from organic sources such as blood, tankage, cottonseed-meal, castor pomace, and the like. Much care must be exercised in the use of nitrogen in organic combinations because they are prone to induce "die back," a physiological disease characterized by the exudation of gum on twigs, leaves, and fruit. The several materials entering into the composition of fertilizers, as sulfate of potash, sulfate of ammonia, and acid phosphate (for example) may be purchased separately and mixed by the grower in proper proportions, but more usually they are mixed by the fertilizer manufacturers and sold as complete fertilizers. Fertilizers for nursery trees, and plantings which have not reached bearing age, contain about 6 per cent phosphoric acid, 4 per cent ammonia, and 6 per cent potash, while for bearing trees one containing approximately 8 per cent phosphoric acid, 4 per cent ammonia, and 10 or 12 per cent potash is commonly used. These percentages are of course not absolute, as the exact composition must be governed by the character of the soil, the condition or requirements of the trees, and crops. Growers watch the behavior of their trees carefully and are governed in the use of fertilizers by their general appearance.
Lime is very generally deficient in Florida citrous soils and the trees and fruit are much benefited by applications of ground limestone, broadcasted over the surface at the rate of about two tons to the acre.
The general tendency in the use of commercial fertilizers is to make frequent applications of small amounts, thereby preventing loss from leaching. Applications, by many growers, are made in February, April, June, and September. The composition of these applications is often varied, giving larger amounts of nitrogen in spring and larger proportions of potash in autumn. Young orange trees are fertilized roughly on a basis of one pound to two pounds for each year of age and bearing trees according to their size and crop indications; sometimes as much as thirty or even fifty pounds a tree in the year is applied in the several applications to the latter. These amounts may even be exceeded if the crop in sight justifies.
In fertilizing young trees, the fertilizer is scattered in a band 2 or 3 feet wide, beginning back 6 to 12 inches from the trunk. As they become older, the fertilizer is spread out toward the ends of the branches and in old orchards or groves it is broadcasted over the whole surface, as the roots have made their way into all parts of the soil. After each application of fertilizer the ground is usually cultivated.
Insects and diseases.
The insects which cause most damage in Florida orange groves are the white-fly (Aleyrodes citri), scale insects of different kinds, and the rust mite. In insect- control, fumigation has been carefully tried out but has not met with general favor, and by most growers spraying is considered more satisfactory and practicable. Against the white- fly and scale insects, miscible oil and whale-oil soap sprays are generally used; and against the rust mite, sulfur in some form is effective. For the control of white-fly and scales, most of the spraying is done in the winter dormant season, one thorough application usually giving satisfactory results. Spraying for rust mite is done during the summer months as it injures the skin of the growing fruits, and three or more sprayings are generally necessary. In Florida, beneficial entomogenous fungi are very effective in holding scale insects and white-fly in control.
Among the fungous diseases the most injurious are melanose with which is associated the stem-end-rot, and anthracnose or wither-tip. These may be handled by careful attention to grove sanitation, removing diseased fruit, pruning out dead and injured wood, and by spraying with bordeaux mixture. "Die-back," a physiological trouble to which reference has already been made, may be corrected by changing the method of cultivation and the fertilizer used. The common method is to discontinue cultivation entirely, and use no fertilizers or those drawn only from inorganic sources and rich in potash.
Citrus Canker, a bacterial disease caused by Pseudomonas citri (see also page 2375) has gained a foothold in Florida and threatens serious injury to the citrus industry. The authorities are meeting with success in their determined efforts to stamp it out. No attempts have been made at control, the method of handling it being to burn the affected trees where they stand.
Within recent years much attention has been given to the protection of orange groves against cold. Many different methods have been tried, but protection by means of sheds, tents and the like has been abandoned except for strictly amateur purposes (Figs. 2618, 2619). The trees were not fruitful under the artificial conditions created, or the methods were too costly. In the more exposed sections, the trees are still banked with clean earth, sufficiently high to afford protection to the bud unions. But the chief method of protection is by firing with small wood-fires or with oil-heaters.
Harvesting and marketing.
The season for Florida oranges extends from the latter part of October until June. This is divided into two parts by the Christmas holidays. At that time but little is shipped. Unfortunately, it has been the custom to ship fruit that is green and unfit for consumption. Attempts have been made to correct this mistake by laws and these have helped greatly.
Perhaps the greatest change in harvesting and marketing in the last two decades has been in the disappearance of the small individual packing-house. Most orange groves in Florida are small. 10 to 25 acres, and formerly nearly every owner had his own packinghouse and picked, packed, and shipped his own fruit under his own brand. Now the marketing of the crop is in the hands of the Florida Citrus Exchange, or of individuals or companies operating on a large scale, and the fruit, in large quantities, is handled through centrally located packing-houses equipped with every convenience for the rapid and economical preparation of the fruit for market (Fig. 2620). This noteworthy change has brought about a great improvement in the methods of handling and the uniformity of the pack. Every detail of picking, hauling, handling, packing, and shipping has been carefully investigated and many improvements have been introduced. As a result, the value of the Florida orange in the markets has been greatly increased by the care taken in handling it.
The standard Florida orange box, the size of which is fixed by state law, contains two compartments, each 12 by 12 by 12 inches, or 2 cubic feet of fruit. Oranges of the mandarin group are put up in half- boxes, two of which are fastened together for shipment, known as a "strap." The fruit is arranged in the box according to definite diagrams for each size.
The Florida orange crop has been gradually increasing. In the season of 1914-1815, approximately 7,000,- 000 boxes were produced.
Of the mandarin group, the varieties planted are Satsuma (in the northern part of the state), Dancy, Tangerine, and King. The Dancy originated in Florida; the other two are introductions. A great many varieties of sweet oranges have originated in Florida as noteworthy seedlings in different groves. Perhaps in no fruit-growing region of America was the amateur spirit more strongly developed or was more interest taken in the merits of different varieties. Formerly a great many different sorts were planted, but gradually the most of these have been eliminated until only a few remain. Of these the most important, arranged according to season of ripening, are, Parson Brown, Homosassa, Pineapple, Ruby, Valencia Late (Hart's Tardiff, Hart's Late), and a recent introduction, Lue Gim-Gong, remarkable because of its late-keeping qualities. Of this list, all originated in Florida except Ruby and Valencia. These are introductions from Europe. H. Harold Hume.
Orange-culture in Louisiana.
From the early settlement of Louisiana to the present day, orange-culture has received most attention in the lower Mississippi delta, but for several years past, the other coastal lands have produced fruit in some quantity, and more recently, plantings of the hardy Satsuma variety in particular have been made in the interior sections of the southern half of the state. Originally, the seeds of sweet oranges were planted and the young trees transplanted in and around the home yards and gardens; and, to a slight extent, this method of growing trees is practised yet by individuals. No extensive groves were grown until after the close of the Civil War. At first, groves of these seedling trees only were planted and they proved exceedingly profitable up to the very cold spell of 1895, which destroyed nearly every one in the state. Another freezing calamity, occurring in February, 1899, utterly killed every tree to the ground.
In the meantime, extensive experiments had been made in budding the choice varieties of sweet oranges on various kinds of stocks, and many of the trials demonstrated the power of resisting moderate freezes by certain kinds of root-growth, notably the Poncirus trifoliata. Accordingly, many of the old groves and numbers of new ones were planted in budded stocks, using the buds of selected trees of sweet oranges and establishing them upon the Poncirus trifoliata. The success of this method also led to the growing of grapefruit or pomelo, mandarin or tangerine, and Satsuma and kumquat upon the trifoliata stock.
Budded stock has thus almost entirely superseded sweet seedlings. The sour orange, the bitter-sweet orange, the rough lemons, the grapefruit or pomelo, and the Poncirus trifoliata have all been used successfully as stock for the sweet orange. Meanwhile, with the introduction of the hardy Japanese varieties, including the Satsuma, mandarin or tangerine, these were also budded upon various kinds of stock. In 1895, when the temperature fell to 15° F. in New Orleans, the only trees able to survive this cold were found to consist of the combination of the hardy Japanese varieties budded upon the Poncirus trifoliata. This experience caused the adoption of the trifoliata as the chief stock for future groves. Therefore, nearly all of the groves planted since that time have been made with this stock.
Account must be taken of a frost limit beyond which this combination succumbs to the effects. Such results were evidenced by the unprecedented freeze of February! 1899, which practically wiped out every kind of citrous growth. Since that time, orange-growing made very slow progress for a long time, but gradually the ground was replanted and the industry expanded until plantings are now scattered over most of the southern half of the state, and, at present, many large groves are to be found. Under suitable attention, the industry has brought profitable returns, and the fame of the Louisiana Sweet, also called "creole orange," is widely known for its excellence. These names apply to a great variety of strains, but all are of a type originally introduced from southern Europe and developed by select cultivation. The budded trees bear early and yield in three to five years after being transplanted in the grove. The city of New Orleans furnishes a home market for most of the crop that is raised in the delta, although large shipments are made to northern points. Local consumption generally absorbs the supply grown in other sections.
The Louisiana orange matures ahead of the Florida fruit and is also ready before the California crop ripens, and, therefore, reaches the market when, on account of scarcity, good prices prevail. These facts, coupled with the readily productive soil, seldom requiring any fertilizer, and the abundant rainfall, dispensing with irrigation, make orange-culture attractive in Louisiana.
The most serious drawback is an occasional cold blast from the North in winter or early spring, which drives Gulfward, overcoming the usually balmy weather and temporarily chilling the growth. At rare intervals, such as have been mentioned, a blizzard occurs so intense as to kill the trees outright. How to protect groves against these destructive frosts is an important matter with the orange-growers. Flooding the orchard with water drawn from the adjacent river or bayou, upon the approach of a freeze, has been practised upon a large scale without complete success. The use of oil- burning orchard-heaters, or smudge-pots, comes nearest to solving the problem, and some enterprising growers are equipped with outfits. Other producers sometimes resort to building smudge-fires on the ground. The practice of banking the trees by piling the soil around the trunk to a height of a few feet more or less (Fig. 2622), on the approach of a freezing spell whose intensity and time of coming are usually predicted by the government weather service, is very largely adopted as the next best economical protection against excessive cold. This banking retains vitality in the main trunk, and while the outer limbs may be killed, young shoots will start from the tree when the soil is removed and spring advances. This practice, therefore, gives only partial protection. Should the tree be frozen so as virtually to cause the death of the growth, new shoots from the protected trunk will soon appear, and in a year o two the tree resumes shape and becomes ready to bear a crop. Although the yield is lost for the ensuing interval, yet, by skilful care, the grower is enabled to secure a renewed orchard quickly. A trial with shelters built to cover the trees has shown them to be very expensive and, further, caused shortage of yield by shading the growth in summer.
Insects and diseases.
Unfortunately, not enough attention has been given toward preventing the introduction of pests, both insects and diseases, nor to accomplish their control after becoming established.
Consequently, through carelessness and neglect principally, the pests have spread nearly everywhere and made many trees unproductive. The leading growers have been compelled to fight these enemies in order to produce clean fruit in sufficient quantity to make commercial growing pay. Added to the cost of spraying groves regularly, some packers clean and polish their fruit, which process involves an investment in a properly equipped plant and further labor for the purpose. The chief insect foes are the citrus white-fly (Aleyrodes citri), the purple scale (Lepidosaphes beckii), Glover's or long scale (Lepidosaphes gloverii), and the chaff scale (Parlatoria pergandii).
Recently, the cottony cushion or fluted scale (Icerya purchasi) has appeared to a limited extent in one locality. With the advent of the Argentine ant (Iridomyrmex humilis), the attendance of this pest upon scale insects has greatly increased the abundance of the latter and complicated the problem of their control. Russeting of fruit, due to infestation by mites, occurs in some places. Following the discovery of the canker disease in 1914, many thousands of nursery stock plants and numbers of older trees were entirely destroyed by cutting and burning in efforts to eradicate this incurable evil. The danger of this menace has brought the growers to a realization of the need of having adequate state protective measures provided for the industry. Awakening to the necessity of aiding in the development of citrous culture, the General Assembly in special session during 1915 appropriated $5,000 for eradication of canker, other diseases, and pests. This recognition, however, gives some hope that sufficient provision will be made by the state in the near future to bring it to the fore rank in horticultural prosperity through the suppression of enemies and the promotion of all fitting lines of fruit-growing. The leading orange culturists have effected an organization called the Louisiana Citrus Growers' Association, whose object is to protect their interests against natural foes.
The propagation of oranges is effected directly from seed and from buds. Budding is done at any time of the year from early spring to late fall. When performed in the fall, the buds remain dormant through the winter. The various stocks have particular merits for special soils and other conditions, and several kinds are used, as already said; but when the chief obstacle to successful orange-culture is cold, all other considerations must be dispensed with and only the most resistant stocks used. These stocks, are, first, Poncirus trifoliata, and, second, sour orange. The latter, however, is not very well adapted to the climate much north of the latitude of New Orleans. Hence, nearly all Louisiana groves have been propagated on these two stocks, a large part being on the former.
Planting a grove is always preceded by a nursery, and though home-grown stock is being produced in extensive quantities, most trees for planting are yet brought from outside of the state. The nursery is started by planting the seed of the Poncirus trifoliata or sour orange. When the shoots are one to two years old, they are shield-budded with buds from selected varieties, or rarely grafted to obtain the desired kind of top-growth. One year later, as a rule, the combined growth is large enough to be planted out in groves.
Soil and fertilizer.
The soil selected for groves is first thoroughly prepared and pulverized, and needs to be well drained. The trees are planted at intervals of 12 to 20 feet (some time more or less) apart both ways, and the grove is cultivated until the trees become large enough to shade the ground. After that period, only the weeds and bushes are kept down. Very early or late cultivation of trees is usually discouraged, as having a tendency to induce a too luxuriant, sappy growth, which may be injured by subsequent frosts. The cultivation is usually performed with light plows or suitable cultivators.
A fertilizer containing fifty pounds of nitrogen, fifty pounds potash, and twenty-five pounds phosphoric acid to an acre is the one usually recommended in this state. Of course, special requirements should be considered, depending on the age of trees. Sometimes on rich soils, only a dressing of lime or bone-meal is needed. Truck or leguminous crops may be advantageously grown between the rows of young trees.
In three years after a grove is planted, the trees should begin to bear, increasing their products every year thereafter, and becoming profitable at five to six years of growth. When ripe, the fruit is carefully gathered by hand with clippers, using ladders to reach the high limbs, then assorted and packed in boxes, and shipped to market, generally in New Orleans.
Some idea of the status of production may be obtained from figures secured in 1915 by the entomologist in charge of Tropical and Subtropical Fruit Insect Investigations of the United States Department of Agriculture, having a station in New Orleans. According to the data applying to 361 groves, the yield is classified proportionately as follows: sweet, 63 per cent: mandarin, 20 per cent; tangerine, 5 per cent; navel, 7 per cent; pomelo, 3 per cent; Satsuma, 1 per cent; and Valencia, kumquat and miscellaneous, 1 per cent. On an average, 108 trees are planted to the acre. In Plaquemines, St. Bernard and Cameron parishes, the number of bearing trees amounted to 270,505, while 73,285 trees were found that had not yet borne any fruit. A large part of a tract of 7,000 acres, located near the city of New Orleans, has been planted in groves, and the company is proceeding in preparations to cover the whole area with one vast orchard.
The marketable crop for 1914 was placed at 275,000 boxes by a well-posted commission merchant of New Orleans. To quote his experience during the past twenty years in marketing the fruit, he says: "When my first visits were made to groves, the growers were not disposed to deal with commission merchants, owing to previous unfair treatment, and the industry was entirely without organization. The growers then had no knowledge of the value of their oranges, or of how to market them. They sold their fruit to speculators, who bought it on the trees, for any price that they chose to give for the crop. These speculators' manner of handling the fruit was very crude. Thev pulled the oranges from the trees without the use of clippers, threw them into buckets, dumped them into boxes, hauled them to the boats which sailed for New Orleans, and, in this unattractive fashion, offered the fruit for market in a bruised and decaying state. After educating the growers, they began picking carefully, but without any method of grading or sizing. The first packing efforts were made without using wrapping-paper, though later they were taught how to wrap the fruit. Many years passed, however, before our leading growers were induced to install modern graders, cleaners and polishers. The growers are now using labeled paper and printed boxes, and compete in the principal markets, and have been doing so for the past several seasons, with the best oranges grown elsewhere.
"Louisiana oranges are of the highest quality, being thin-skinned, sweet, juicy, and have a delicious flavor that is not found in any other orange. A number of markets take them at higher net prices to the growers than are obtained for either Florida or California oranges. A vastly greater quantity than we now raise could be handled to equally good advantage. The opportunity to market so many more than are now grown should be an inducement to an enormously increased acreage.
"Any number of growers who have shipped from 1,000 to 10,000 boxes of oranges are willing to testify that results during the past five years have been from $1.25 to $1.75 per box net on the trees. These prices included culls and all varieties of oranges which they grew. The production per tree compares favorably with other citrous fruit growing sections. Our real industry, however, lies in our commercial varieties known as the Louisiana Sweet orange. This fruit comes on the market about the first of October, and shipments continue until the first of January. The season could be extended, but, on account of our limited crops, we find no necessity to hold the fruit any longer. We grow successfully the Satsuma, which begins to move in the latter part of September, and shipments are made until the end of October. Then follows our sweet high-grade mandarin; these first appear in October and last until the middle of November, sometimes extending a month longer. The tangerine starts to move about the middle of November and continues until the latter part of December. The navel orange is also grown very successfully, the only drawback being that they grow too large, as the market is limited for extra-large sizes. Valencias are ready for market in February and the season extends until March; they usually command $1 per box more than Louisiana Sweets for the reason that the bulk of the sweet crop is then sold out. thus leaving a bare market. Grapefruit is perfectly adapted to our soil and climate. It is a large producer and of a quality equal, if not superior, to that grown elsewhere. Our prices have been very high, on account of which our growers are generally increasing their acreage of this fruit tree." E. S. Tucker.
Orange-culture in California.
Orange seeds were brought into California by the Jesuit missionaries who planted the first orchard at San Gabriel Mission in 1804. The success of these trees so impressed William Wolfskill, a Kentucky trapper of German blood, that he planted the first commercial orange orchard in 1841 on the ground now occupied by the Arcade Passenger Station of the Southern Pacific Railway in the city of Los Angeles. Wolfskill was highly successful and gradually enlarged his orchard of seedling trees from 2 to 70 acres. It was he who, in 1877, shipped the first full carload of oranges across the Rocky Mountains to eastern markets.
Thomas A. Garey, of Los Angeles, established the first citrous nursery in 1865 and by propagating trees and introducing new varieties, played a prominent part in establishing the industry.
Extensive commercial development of orange-culture may be said to have begun with the completion of the Southern Pacific Railroad's connections with the East in 1876. Three years later, the exhibition of the first fruits of the Washington Navel orange at Riverside gave another impetus to citrous planting, but the greatest development came with the completion of the Santa Fe's competing line of railroad which was opened about 1885.
The strong demand for California oranges in the eastern markets and the high prices received by some, brought on a period of frenzied planting and speculation which culminated hi 1882-1883, when drought, frost, scale insects, and the lack of a coherent marketing organization, conspired rudely to awaken from their golden dreams many who had rushed into the business with insufficient knowledge and capital to weather a period of depression. Since 1890, expansion has been rapid but conservative; better distribution and increased consumption have taken care of the increased production. At present (1915) production is increasing much more rapidly than consumption. The growth in production may best be shown by the shipments for the past twenty-four years:
California Citrous Shipments.
(Including all citrous fruits.)
The chief factors which have influenced the growth of the industry are: (1) The very favorable climatic and soil conditions. (2) The building of the railroads. (3) The great success of the Washington Navel variety as a regular and heavy bearer, a good shipper, and a splendid seller. (4) The protective duties imposed upon imported citrous fruits by the United States Congress. These duties have been continuously in force since July 4, 1789, although they have been changed in amount nineteen tunes during that period. (5) The marked enterprise of the persons engaged in the business. The California citrous business is peculiar in that the persons who have made it are, in so many cases, retired business or professional men from the East and North who, having lost their health in the acquisition of wealth, have bought and developed citrous properties, thus bringing into the industry much-needed capital, commercial ability, and business habits. (6) Cooperative packing and marketing. By this means a uniform standard pack has been established, better distribution secured, and, by uniting their strength, the growers have been able to secure from the railroads many valuable concessions. (7) The introduction of the Australian lady-bird beetle, Novius cardinalis, and its control of the cottony cushion scale. (8) The development of the method of refrigeration in transit. (9) Rigid inspection and quarantine methods against injurious insect pests and diseases. By this means the state has so far been kept free from the Mexican orange maggot, the Mediterranean fruit-fly, and many other damaging pests, such as the citrus canker. (10) Scientific investigations and research by the United States Department of Agriculture, the State University Agricultural Experiment Station, and the State Commission of Horticulture. (11) The great advertising activities by the Chambers of Commerce of the various cities and towns. It is estimated that in 1915 the California citrous industry represents an investment of $200,000,000 and gives continuous employment to the equivalent of 40,000 persons. Not less than 200,000 acres were devoted to citrous fruits at the end of 1914.
The orange-producing lands of California are scattered from San Diego to Shasta County, a north-and- south distance of 450 miles. It is a peculiar fact that there are orange orchards in California in the same latitude with New York City; Peoria, Illinois; Lincoln, Nebraska; and Salt Lake City, Utah. This is made possible by the peculiar topography of the state whereby the mountain ranges are so arranged that the cold winds of the North are shut out, and the warm southwesterly breezes from the Pacific are admitted. The great interior valleys, such as the Sacramento, San Joaquin and Imperial, are very hot and dry. The chief citrous areas of these valleys are situated on the foothills about their rims. West and south of the Coast Range, the fogs and moist ocean breezes protect, to an extent, from sudden fluctuations in temperature, and orange orchards extend from the foothills well out upon the valley floor. The factors which determine orange areas are: frequency of frosts, water-supply, transportation, and soil conditions. The greatest and most productive area embraces the country around Los Angeles, Riverside, Redlands, Corona, Orange and Santa Ana. The second area in importance is the Por- terville section in Tulare County. Other important areas are in San Diego, Santa Barbara, Ventura, Kern, Fresno, Sacramento, Yuba, and Butte counties. Large extensions are now under way in Ventura, Los Angeles, Tulare, Fresno, Glenn, Sacramento and Tehama counties. On account of the higher temperatures, the interior valley oranges ripen much earlier than those grown near the coast. As some of these valley orchards lie far to the north of the coast country orchards, the unusual procedure of shipping early ripening fruits southward to market is accounted for.
Almost all the old seedling orchards of early days have given place to budded trees. Several kinds of stocks are used. The most popular root at present is the Florida sour orange, because it is better suited to heavy lands and is markedly resistant to gum disease and foot-rot. Sweet orange root is desirable on light well-aerated soils. Grapefruit root is being increasingly used and is especially satisfactory on desert soils of a granitic nature. The use of China lemon root has been discontinued entirely. The rough lemon and trifoliata roots are little used, as they very rarely show any advantage over the sour or pomelo, and in many cases suffer in comparison with them. Seeds are usually planted under the partial shade of a lath-house. They are covered with an inch of sterile sand and watered with great care in order to prevent serious loss from damping-off fungi. After a year in the lath-house, the seedlings are transplanted into the field 12 inches apart in rows 4 feet apart. After a year's growth, they are budded from 2 to 6 inches from the ground. After the bud has set, the top is cut away and the young shoot trained to a lath stake and headed at about 33 inches. Budding is done both in the fall and in the spring and early summer. Some of the more rapid-growing trees will be large enough to set in orchard form at one year from the bud, but some will require two years. Often the slower-growing trees are the more desirable, having been budded from wood with heavy fruiting tendencies. In fact, a pair of calipers is a poor gauge of the value of an orange tree. Many fine large nursery trees produce but little fruit in after years. The selection of buds is a very important matter. Oranges vary and sport much more commonly than apples or pears and the greatest care and eternal vigilance is necessary in order to keep the nurseries free from undesirable sports. The worthless "Australian" or "hobo'.' trees which make up such a shockingly large proportion of many orchards are the result of ignorance or carelessness in selecting buds on the part of nurserymen whose only concern is to sell nursery stock.
Citrous nursery trees are usually dug and transported with a twenty- to forty-pound ball of earth about the roots inclosed in burlap. When set out, the cords are cut and the comers turned down but the sack is not removed, inasmuch as it quickly decays in the soil. Orange trees will grow just as well when dug with bare roots as when balled, provided the sun and dry desert air are not allowed to touch the moist roots even for a few minutes. There is the greatest difficulty in impressing laborers with the importance of this danger, which has led to the custom of balling trees and paying transportation charges on the extra soil as a precautionary measure. Balled trees retain then- leaves, while bare-root trees have the leaves removed when they are dug.
The prevailing custom in California is to plant the trees in orchard form in squares 22 by 22 feet or 22 by 24 feet, the former requiring ninety trees to the acre. Great care is used to keep the bud-union above the ground and free from the soil. Yucca or paraffined pasteboard trunk-protectors are almost universally used to prevent sunburn. Often the trees are planted out ahead of canal-construction and watered for a year or two from a tank wagon.
Soils and fertilizers.
The character of soil for orange-culture is not so important as its physical arrangement. If the soil is deep, fertile, well drained, anal free from layers or strata of a different physical make-up from the main body of the soil, for 5 or 6 feet in depth, it does not matter so much whether the soil is light sand, heavy adobe, loam, or disintegrated desert granite. Excellent orange orchards exist in all these types of soil. It ia more pleasant and convenient to cultivate a loam than an adobe, and it is easier to irrigate a loam than a light sand. These things should always be taken into account, but the successful growth of the trees depends more on the uniformity than upon the character of the soil. Upon shallow soils, trees will succeed for a while, but artificial feeding must be resorted to earlier. No soil less than 2 feet deep should be considered safe for oranges. Soils underlaid by hardpan, or layers of open gravel are apt to cause functional derangements of the nutrition of the trees. The ideal soil is a friable easily worked loam, 8 or more feet deep, growing gradually lighter in color and texture as the depth increases. This not only provides a large storehouse of plant-food but a great reservoir to hold water. Of the two most common conditions, it is much better to have a light topsoil over heavy clay subsoil than a heavy clay top- Boil over sand or gravel.
It is the custom to, plow the orchards once a year, usually in the spring at the time of turning under the green-manure crop. Throughout the spring and summer, the soil is clean cultivated to a depth of 4 to 8 inches. Thorough cultivation and the reestablishment of the dust mulch follows each irrigation during Bummer. For this work, either disc, spike-tooth cultivators, or spading harrows drawn by three or four horses are used. Orchard tractors are beginning to take the place of horses in the interior valleys. In some soils, the oft-repeated tramping of the horses causes the formation of a "plow-sole" which interferes with the downward course of the irrigating water. This may be broken up every second or third year by running a subsoil plow through the middles in such a way as to cut as few of the large roots as possible. Some growers have abandoned all tillage and cover the ground 8 or 10 inches deep with mulch. The trees do well under this system but the mulching material is expensive and the danger from fire during the dry season is very great.
California soils are, as a rule; noted for their low content of humus. It is imperative that the humus-content be increased and maintained by generous additions of organic matter. The chief source of humus is the vetch green-manure crop, but where the trees are large and shade the ground, the growth of vetch amounts to little, and other means must be resorted to. Large quantities of stable manure, grain, hay, lima- bean straw, and even alfalfa hay, have been used for this purpose, and of late attention has been called to the possibility of using kelp, which is plentiful along the Pacific coast. How to maintain a high humus- content in the soil is today one of the chief problems before the industry.
Commercial fertilizers are commonly used and in increasing amounts from the time the trees are five or six years old. There is probably more difference of opinion and diversity in practice in connection with the use of commercial fertilizers than with any other phase of the business. The amount of application runs from two to forty pounds to each tree, annually, depending upon its size and age. Some apply the fertilizer all at one time, just before the spring plowing, while some make two or three applications a year. California soils are usually high in potassium, and wherever the humus is high, this element is hardly needed. In many cases in which the soil is deep, rich and high in humus, an annual application of ten to fifteen pounds of ground phosphate rock to a tree, together with the vetch crop and five tons of alfalfa or bean straw to the acre every alternate year will be a satisfactory program. Orange trees are very susceptible to alkali. Where the soil contains .2 of 1 per cent of total salts, the trees begin to decline. A total salt- content of less than .1 of 1 per cent is usually considered safe. These figures will vary somewhat, however, according to the proportion of the different salts, which, taken together, are known as "alkali," some of which (such as sodium carbonate) are very injurious.
On none of the citrous areas of California is the rainfall sufficient. Irrigation is practised in every orchard. For the most part, water is taken out of streams near the upper headwaters and conveyed by gravity through cement canals sometimes for hundreds of miles to the citrous orchards. Often the descending water generates electrical energy to be used in pumping additional supplies from wells. The water is distributed through steel or concrete pipe-lines and delivered at the upper end of the furrows. Usually the grower buys the water-right with the land and is assessed annually for the upkeep of the system serving him. The keys to the water gates are kept by a water-boss or "zanjero" who measures out to each grower his proper allotment. The amount of water required varies with the character of the soil and the age of the trees. Full- grown bearing trees require from 1 ordinary miner's inch continuous flow to 10 acres up to as much as an inch to 3 acres, depending on the rainfall and whether the soil is a heavy clay or an open sand or gravel. An irrigation is given every month or six weeks during the summer and less often in winter, according to the rains. In heavy soils, the water is run for three or four days at each irrigation in very small streams through four deep furrows to each tree row. The water is cut off when tests with a soil-tube show the soil to be soaked 5 feet deep. In very light porous soils, it is necessary to throw up ridges each way. leaving each tree in the center of a large basin. These basins are filled quickly with a large stream. It is only by the use of large, rapid streams that water may be conveyed across and distributed over such open and porous soils.
The common or spring vetch (Vicia sativa) is very commonly grown as a green-manure crop in southern California. It is planted in September and turned under in February before the trees start the spring growth. The seeds are large and germinate well and the vines suffer less from the trampling incident to harvest than some other green-manure plants. Canada field peas, Tangier peas, bur clover, fenugreek, and sour clover (Melilotus indica) are occasionally used in place of the vetch. In northern California, bur clover volunteers satisfactorily and is commonly used. Summer green- manure crops, such as cowpeas, are coming into use wherever there is sufficient cheap water available to supply both the trees and the peas during the dry hot months.
Orange trees are pruned somewhat differently according to the variety. The young Washington Navel tree should not be pruned for the first two or three years after being headed and set in the orchard. Especially if budded from the best type of wood, it may be depended upon to form a good head by itself. Suckers should of course be removed whenever they appear. The Valencia is a more rampant grower, and the young upright shoots are apt to grow too long before branching. They should be pinched back. In pruning old trees, the following rules are thought to embody the best practice: Remove suckers whenever and wherever they appear. Remove the too vigorous vertical shoots which tend to produce coarse fruit. Remove old brush of waning vitality. Thin the tops and, to some extent, the sides so as to allow proper airing and lighting of the interior foliage, thus encouraging the production of high quality, inside fruit. Remove all dead twigs from the fruiting brush. Navel trees rarely need propping, while Valencia trees, unless the limbs are kept short and stout by pinching, are apt to require a great deal of propping.
California oranges are harvested the year round, the Navels, from November 1 to May 1; seedlings and miscellaneous varieties during May; and the Valencias, from June 1 to November 1, thus overlapping the next Navel crop. A ripe Navel will remain in prime condition on the tree for two months, a Valencia for six months or longer.
Oranges are picked with extraordinary care to prevent injury. They are never pulled, but are clipped flush with the "button" with round-pointed clippers. The fruit is collected in canvas bags carried by the picker, which open at the bottom and allow the fruit to slide gently into wooden lug-boxes. The unbroken skin of an orange is very resistant to decay, but the least abrasion, no matter how slight, whether caused by withdrawing the orange carelessly from the branches, or by the finger-nails, or by placing the fruit in boxes in the bottom of which a few grains of sand or dirt have fallen, is almost sure to become inoculated with spores of decay fungi, such as the blue-mold or the soft-rot. Many growers do not take all the fruit from the trees at one picking, but pick the lower fruit first, thus getting it out of the way of frosts which are most severe near the ground; and brown-rot, which is splashed up from the soil by winter rains; and also to relieve the strain on the branches. The standard car is made up of a certain proportion of the different sizes, hence it is customary to go over those remaining on the trees, selecting certain sizes to meet the daily demands at the packing-house. Formerly, picking was paid for by the oox, but the tremendous losses from the decay resulting from rapid work has brought about a complete change to day labor.
The lug-boxes of fruit are hauled to the packinghouse on spring wagons or auto trucks and weighed in. The fruit is then stored in the same boxes from one to five days, in order that the rind may shrink and the surface cells become less turgid and subject to abrasion. In this condition, oranges will stand a large amount of handling and tumbling about in the padded machines without injury. The fruit is first run through a brasher which removes dust and dirt. In case there is smut from scale insects or soot from oil-pots, they are put through a washing machine containing a 1/50 of 1 per cent solution of copper sulfate in water. The fruit next travels on belts before the graders who, considering color, shape, smoothness and blemishes, sort the salable fruit into three grades, standard, choice, and fancy. Each one of these grades, after being weighed on automatic scales, passes through a separate sizing machine which delivers each of the eight or ten sizes into a separate, heavily- padded canvas bin. The packers, mostly women, wrap each fruit in printed absorbent tissue paper and place it in the box with great dexterity and skill, averaging sixty boxes a day. A very high pack is customary, and after the covers are forced on and nailed, the boxes are delivered by automatic carriers to the car or the pre- cooling room. One hundred lug-boxes will usually pack put about sixty packed boxes. The cars vary in capacity, depending on whether they are provided with collapsible ice-bunkers. The standard car contains 384 boxes loaded two tiers on end and six rows wide and including not more than 10 per cent of the following sizes, 96, 112, 250, and not over 20 per cent of the 126 size. The remainder of the car may be divided among the 150, 176, 200 and 216 sizes. Cars other than standard are discounted on the market according to the number of the off sizes they contain. The freight is figured on an estimated weight of seventy-two pounds to the box. In summer about five tons of ice are placed in the bunkers after loading and the cars are re-iced in transit as needed, unless they have been pre-cooled, in which case the initial icing suffices. The average time between San Bernardino where the Santa Fe trains are made up, or Colton where the Southern Pacific trains are made up, and New York is about fourteen days. The packing-houses vary in capacity up to twenty carloads a day. In no other fruit industry have the appliances for handling the fruit in the packing-house been so highly developed. While a few of the larger growers still look after the sales of their own fruit, and a few sell the fruit on the trees to various fruit companies and commission men, the larger part turn their fruit over to a large and very strong cooperative organization of growers known as the California Fruit-Growers' Exchange. This organization began business in 1895 but was reorganized in 1905. In 1915, the Exchange handled about 62 per cent of all the citrous fruits shipped out of the state. The Exchange has greatly increased the consumption of citrous fruits by advertising and better distribution. The business of the Exchange is to "provide for the marketing of all the citrous fruit of members at the lowest possible cost under uniform methods, and in a manner to secure to each grower the certain marketing of his fruit and the full average price to be obtained in the market for the entire season. Much of the fertilizer and other supplies used in the industry are secured through a cooperative store known as the Growers' Supply Company. In 1914 this store did a business of $3,319,062.04 at an operating expense to the members of ¾ of 1 per cent on each dollar of business transacted.
A large list of varieties of oranges has been tested out under California conditions, but the law of "the survival of the fittest" has worked rapidly and today two varieties dominate the field, viz., the Washington Navel and the Valencia Late. While old orchards of other varieties are still producing considerable quantities of fruit, new plantings are now practically limited to these two varieties. The Washington Navel originated at Bahia, Brazil, in the early part of the nineteenth century and was introduced into California by William Saunders, of the Department of Agriculture, in 1870, through Mrs. L. C. Tibbet. of Riverside. This variety now known as the "king of oranges" rapidly gained in popularity until at the present time nearly 80,000 acres of it are planted. It owes it success to the following characteristics: fruit large, smooth, with fine color and flavor, seedless, a splendid shipper, and having a navel mark which serves on the market as a trade-mark. The tree is semi-dwarf, precocious, prolific, and a regular bearer. The Navel is prone to sport and much care should be used in cutting Dud wood. The Thomson Improved is the best example of a desirable sport from the Navel. The Navel reaches its highest development in the interior valleys. The Valencia Late originated in the Azores and was introduced into the United States in 1870 by S. B. Parsons, of Lone Island, through Thomas Rivers, of England. The Valencia reaches its highest development along the coast. It is a poorer orange than the Navel, but it is the only variety which remains on the trees in good condition until late fall or early winter. Other varieties still marketed to some extent from old groves are Mediterranean Sweet, Paper Rind, Jaffa, Ruby Blood, and Seedlings.
Insects and diseases.
The following insect pests occur in the California citrous orchards: the black scale, red scale, yellow scale, purple scale, cottony cushion scale, soft brown scale, citricola scale, hemispherical scale, greedy scale, oleander scale, citrus mealy-bug, red-spiders, silver mite, thrips, aphis, orange tortrix, Fuller's rose beetle, and a few others. More than $500,000 are expended in southern California each year combating the scale insects. The cottony cushion is controlled by a predaceous beetle, but the other scales are controlled by fumigation with hydrocyanic acid gas under movable tents made especially for the purpose. The cost of fumigating a medium-sized tree averages about 35 cents and the work must usually be repeated every second year. Spraying citrous trees for scale insects is almost obsolete in California. The black and purple scales are most damaging along the coast, while the red and yellow are severe in the interior valleys as well as the coast country. In Tulare County, a species of thrips has done much damage by scarring the fruit and distorting the leaves. The Tortrix worm is the only insect which burrows into the orange.
Gum disease is the most serious fungous disease of the tree in California, while armillaria root-rot, maldi-gomma, trunk-rot (Schizophyllum), twig-blight (Sclerotinia), wither-tip (Colletotrichum), and damp-off fungi are minor troubles. Physiological diseases of the tree include squamosis or scaly bark, exanthema, chlorosis, mottled-leaf, die-back, and leaf-gumming. Fungous diseases of the fruit are: brown-rot (Pythiacystis citrophthora), blue-mold (Penicillium italicum), green- mold (Penicillium digitatum), gray-mold (Botrytis vulgaris), sooty-mold (Melilola Camelliae), cottony-mold (Sclerotinia sp.), gray scurf and navel end-rot (Alternaria citri).
Physiological defects of the fruit are: sunburn, frost, off-bloom, exanthema, corrugations, bottle-neck, fingers, yellow-spot, double navel, brown-spot, stem-end spot, cracks, puffs, splits, peteca, red-blotch, and others.
Control measures, more or less satisfactory, have been worked out for the larger number of insects and diseases prevalent in the state.
Protection against frost.
The different kinds of citrous fruits vary in the amount of cold they will endure without injury. The amount of injury done by a given degree of cold upon a given variety will vary, also depending upon the degree of dormancy, the state of the weather just preceding and just after the freeze and the length of time the cold lasts. Many thousand acres of land in California are well suited for growing citrous fruits except for the fact that they are subject to occasional frosts which destroy the crop and sometimes injure the trees. It is natural, therefore, that under such conditions, the citrous growers of California should be pioneers in the work of frost-protection. A great deal of experimenting has been done along the line of diminishing the radiation of heat and by raising the dew-point. It has been demonstrated, however, that the most practicable and satisfactory method of fighting frost is by adding heat directly to the trees through the agency of fires distributed throughout the orchard. Some ten or more types of patent orchard-heaters are now on the market, but the kind the citrous growers find most satisfactory is a round sheet-iron pot of three or five gallons capacity fitted for burning low-grade distillate or crude-oil. The pot should be provided with a suitable cover to keep out the rain and a draught by which the size of the flame may be regulated to suit the degree of cold to be overcome. The less smoke is produced, the better. The smudge commonly used by deciduous fruit-growers is objected to on the ground that the fruit is covered with soot and it is both expensive and damaging to the keeping quality of the fruit to clean it properly. Citrous growers prefer to generate the additional amount of heat necessary to compensate for the lack of smoke.
Many small fires are better than a few large ones. The heaters are usually placed one to each tree or about ninety to the acre throughout the orchard with an extra row along the windward sides. Each ranch should be provided with an oil-reservoir which will hold enough oil to fill all the heaters on the ranch five or six times. When properly equipped with heaters, the temperature of an orchard can be maintained during the night at 10°F. above that of the surrounding country.
The effects of frost on oranges appear as a spotting of the skin and a softening of the outward side of exposed fruits. The juice disappears, leaving the interior dry and pithy. Slightly frosted oranges occasionally develop a very bitter taste. Fruit from the same trees will often grade all the way from sound to badly frosted, depending on the position the fruit occupied on the tree. The method of separating sound from frozen fruit is based on specific gravity.
The machine consists of an oblong tank through which water may be made to circulate at definite speeds by a small propeller. The oranges roll down an incline and drop into the moving water from a height of a foot or more. The light frosted oranges bob up to the surface quickly, while the sound, heavy fruit is slower to rise. Meanwhile the oranges have been carried along by the current, the sound fruit passing under, and being caught by a horizontal wire screen, while the light fruit is carried along above it. At the farther end of the tank the two grades are lifted by conveyors and delivered to separate bins. By adjusting the position of the screen and the rate of flow of the water, any degree of separation desired may be secured.
The manufacture of citrous oils, perfumes, citrate of lime, and other by-products has never been developed commercially in California, although at present much experimenting is being done in an effort to encourage such an industry, which is badly needed. At present, the culls mostly go to waste or are applied to the land as fertilizer. The manufacture of marmalade and citrate of lime has been attempted but has not as yet assumed importance.
|Standard Cyclopedia of Horticulture|
Citrus sinensis Osbeck (C. Aurantium var. sinensis, Linn. C. Aurantium, Lour, et Auct., not Linn.). Common or Sweet Orange. A medium-sized tree, with a rounded top and regular branches: spines, when present, slender, flexible, rather blunt: lvs. medium-sized, rounded at the base, pointed at the apex; petiole narrowly winged, articulated both with the blade and the twig: fls. medium-sized, smaller than those of the sour orange, white in the bud; petals white on both surfaces; stamens 20-25; ovary subglobose, clearly delimited from the deciduous style: fr. sub- globose or oval, pith solid, pulp sweet, membranes not bitter in taste, segms. 10-12 or 13 in number; seeds cuneate-ovoid with rugose margined plane surfaces, white inside.—The common or sweet orange is widely cult, in all the tropical and subtropical regions of the world. It is rather tender, not so hardy as the sour or Seville orange, but much more cold-resistant than the lemon or lime. A very few orange trees occur in a semi- wild state in S. Fla. Sweet oranges were doubtless intro. into Fla. by the Spaniards nearly four centuries ago and, as they were prop, by seeds until within the last half-century, many local varieties have arisen there. Orange-culture has reached its highest development in S. Calif., where it constitutes one of the most important agricultural industries. Fla. is second only to Calif. in the extent and value of the orange groves, while some oranges arc grown in favored spots in La., Texas, and Ariz.—Oranges are the best known and probably the most highly esteemed dessert fr. A few are used in cooking and the peel is sometimes candied. An essential oil is also pressed from the peel. The sweet orange is commonly used as a stock on which to graft other species of citrous frs. It grows well on light well-drained loam or sandy loam soil. On heavy soil it is subject to the mal di gomma or foot- rot. Very many varieties are in cult. Some of the principal sorts grown in the U. S. are listed here. (1) Florida seedlings— varieties originated in Fla. as a result of prop, oranges from seed, mostly strong-growing trees: Parson Brown. Frs. medium-sized, very early. Pineapple. Frs. medium or large, very juicy; seeds rather numerous: midseason: tree a strong grower. Homosassa. Frs. medium-sized, very juicy: a good bearer and keeper: tree nearly thornless. Madam Vinous. Frs. medium or large; pulp coarse-grained, juicy; midseason. Nonpareil. Frs. rather large, flattened; pulp fine-grained, juicy: tree vigorous. Also Arcadia, Summit, Foster, Hick, Magnum Bonum, May, Old Vini. Osceola, Stark, Whittaker, and very many others of the same general type. (2) Florida mutations or hybrids—new sorts originated in Fla., usually differing in some striking way from the old Fla. seedling ranges, perhaps through hybridization with foreign varieties. Boone (Boone's Early). Frs. medium size, strongly oval or oblong, very juicy, very late, keeping well on the tree: lvs. with petioles varying in width. Lue Gim Gong. Frs. oval, juicy, ripening very late and holding very well on the tree, even until late summer. A variety newly intro. into cult. Drake Star. A rare variety with variegated foliage; usually a poor bearer but sometimes bearing a good crop of excellent fr. (3) Mediterranean varieties, largely intro. into Fla. by Sanford and Lyman Phelps, about 30-40 years ago: Ruby. Frs. small or medium-sized; peel red-orange; pulp streaked with red when fully ripe, juicy; seeds rather few: rather late: tree vigorous, nearly thornless, prolific. St. Michael. Frs. medium-sized, oblong, red-blotched when ripe; flesh wine-red; seeds few; rather early. Jaffa. Frs. large, oblong, juicy; seeds few. Possibly not the same as the celebrated orange of Jaffa, Palestine. Mediterranean Sweet. Frs. large, oval, juicy, late: tree nearly thornless. Majorca. Frs. round or slightly flattened, juicy: rather late. Hart (Hart's Tardiff). Frs. round or slightly oval, medium to large size, juicy; seeds few; ripens very late: similar to the next and thought by some to be identical. Valencia (Valencia Late). Frs. medium to large, oval or rounded, juicy, nearly seedless, very late. A prolific variety, largely grown in Calif. and held in cold storage until early autumn. There are many other Medit. varieties of nearly or quite as much value as some of the above, such as, Centennial, Du Roi, Joppa, Paper Rind, Prata, Saul Blood, St. Michael (Blood), etc.—The navel oranges all show a second smaller more or less included fr. formed at the tip of the main fr. Many varieties are of foreign origin. Washington (Bahia, Washington Navel). Fr. large, rounded slightly, pointed at apex; flesh firm, juicy; skin very tough; seedless: early midseason. The most famous variety of oranges intro. from Bahia, Brazil, by Wm. Saunders of the U. S. Dept. of Agric. in 1870. Its cult. has steadily extended in Calif. until it is the principal variety grown there. It does not succeed well in Fla. Thompson (Thompson's Improved Navel). A smooth-skinned hard-fleshed variety found by A. D. Shamel to arise as a mutation from the preceding, to which it is inferior in quality though better in appearance. Australian. Frs. large, coarse: tree vigorous, but a shy bearer. Also found by Shamel as a variation of the Washington Navel (Bahia). Surprise. Fr. medium-sized, rounded or even slightly flattened, juicy, early, seedless. A variety originated by E. S. Hubbard, of Fla. Double Imperial. Fr. small or medium-sized, navel hidden: pulp firm; seeds few or none. A Brazilian variety, said to fruit well in Fla. when budded on trifoliate orange stock. There are many other varieties of navel oranges occasionally grown on a commercial scale. In Calif., among others, Golden Nugget and Navelencia; in Fla., Egyptian, Melitensis, and Sustain are known. There are doubtless many more navel oranges which should be tested. See Orange. Hybrids: Citranges are hardy hybrids between the common sweet orange and the trifoliate orange, Poncirus trifoliata. The principal varieties are the Rusk, Morton, Colman, Savage, Cunningham and Saunders. See description under Citrange.CH
- McPhee, John. Oranges (1966) - focuses on Florida groves.
- Sackman, Douglas Cazaux. Orange Empire: California and the Fruits of Eden (2005) comprehensive, multidimensional history of citrus industry in California
- Train, John. Oranges (2006)
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