MIAMI OtCH TIMES
UNIVERSITY OF FLORIDA
State-wide Sponsor of the Florida Writers' Project
FEDERAL WORKS AGENCY
JOHN M. CARMODY, Administrator
WORK PROJECTS ADMINISTRATION
HOWARD (). HUNTER, Acting Commissioner FLORENCE KERR, Assistant Commissioner WILBUR E. HARKNESS, State Administrator
As early as 1860, Florida pineapples were being shipped to many northern markets where, because of fheir exceptional qualities, they brought top prices. By the early 1900's the area along the east coast from Indian River to Miami was producing 1,000,000 crates annually. Disease and adverse tariffs gradually put an end to the enterprise, and within the next decade thousands of acres were abandoned.
Recent experiments conducted by the U. S. Bureau of Plant Industry in co-operation with the State Department' of Agriculture, have developed improved methods of cultivation, the planting of hardier varieties, eradication of pests, and the perfection of new fertilizers. Through these efforts Florida seems destined to regain its former importance in the growing of this delicious and healthful tropical fruit.
ROLLA A. SOUTHWORTH, Director Division of Community Service Programs
CARITA DOGGETT CORSE, Supervisor
Florida Writers' Project Work Projects Administration
Production in Florida i860 to 1920 .................. 2
Selecting a Site................................. 5
Varieties ..................................... 7
Propagation .................................... 8
Cultivation ..................................... 10
Fertilizers ...................................... i2
Shed Culture................................... 14
Harvesting and Marketing...................... 15
Yields and Returns .............................. 17
Pests and Diseases............................. 19
PINEAPPLE GROWING IN FLORIDA
The pineapple is regarded as a native of tropical South America. It is said, however, that early Spanish explorers in the West Indies found the natives had long been cultivating a remarkably luscious fruit, which they called the anana. Seeing in the fruit some resemblance to a huge pine cone the Spaniards named it the "pine."
The restless explorers of the New World brought this fruit to Europe where it found immediate favor and became widely cultivated in private gardens. The earliest recorded mention of the pineapple in English literature occurs in the Diary of John Evelyn (1620-1706) who states that he first tasted the fruit at the table of Charles II.
In temperate zones this fruit was for some time produced under glass but the practice was abandoned with the advent of improved transportation facilities, when its cultivation spread to more favorable regions. Although the principal fields are now in the Hawaiian Islands and the West Indies, the fruit is also a valuable crop in the Azores, northern Africa, Queensland, and 'in Florida.
PRODUCTION IN FLORIDA 1860 to 1920
The pineapple was one of the first tropical fruits to become important in Florida agriculture. It was introduced in i860 by Benjamin Baker of Key West, who secured slips from Cuba and made an experimental planting on Plantation Key. His efforts were so successful and his profits so amazing that others entered the industry and the chain of keys became dotted with thriving plantations.
Some of the larger plantations were equipped with tram-roads for the transportation of supplies and fruit. During harvest season lines of chanting Negroes with wide, flat baskets heaped high with fragrant pines, fried across the beach to small boats which plied back and forth to the waiting schooners.
Cultivation as practiced on the keys was simple but wasteful. It was at first supposed that the land needed to be "hot." Accordingly, forests were cut down, the wood burned and slips were planted in the ashes without being fertilized. Although the fields were weeded but once or twice a year a heavy crop was produced.
The humus was depleted in time and the shallow soils became unproductive. The plantations were abandoned and their equipment left to rot under a tangle of vines which overran the neglected fields.
Meanwhile the industry had been introduced into other parts of Florida. Shed-plantings spread through the central counties. These were gradually abandoned when it was found that the sand-dune area along the east coast could be successfully cultivated.
By 1890 pineapple production was largely centered in this section which developed rapidly when the Florida East Coast Railway was extended to the lower counties. Despite natural disadvantages the industry made phenomenal strides and by 1910, more than 5,000 acres of the white sandy ridge extending from Oslo to Miami, were devoted to pineapples. At that time
this area was producing more than a million crates annually, the largest crop harvested in the State. It is claimed that at the peak of the season, from 5o to 70 freight cars were required each day to move the pineapple crop. Production was heaviest along the Indian River where plantings extended for miles in an unbroken expanse.
For the most part this region was originally covered with sterile sand supporting a growth of scattered pines, but with the application of fertilizers it became exceedingly productive. The crops produced were so great and the returns so lucrative that a few acres were reputed to yield a comfortable income.
The bonanza did not last. Following the extension of the Florida East Coast Railway to Key West a car-ferry was established between that city and Havana. Soon solid trainloads of pines produced by cheap island labor were poured into northern markets to compete with those grown in Florida. After the annexation of the Hawaiian Islands an extensive pineapple canning industry was developed there and its products, duty free m the United States, combined with the West Indian pines, to make further reductions in the profits of Florida growers.
At this time, plants in the old established east coast plantations began to decrease in vigor and production. Crop expectations diminished fo a point where returns no longer justified the labor expended on the fields. By 1917 when the decline became general, thousands of acres were abandoned. During the same year two heavy frosts destroyed most of the remaining fields. A few replantings were effected but by 1920 only two or three acres remained.
On the west coast, in the vicinity of Charlotte Harbor, quality fruit had been grown under sheds. The industry was considered promising in 1915, when 6o acres were under cultivation in this manner. This, too, failed and in the Florida Agriculture Statistical Report for 1936-37 no plantings are recorded for the area.
The sharp decline of pineapple production in the State is
reflected in statistics which show a recession from 38,793,343 plants in 1910, to 1,375,655 in 193o. Of these, 1,002,895 were bearing plants, the principal production areas being in east coast counties. The yield for that year was given as 11,906 crates. A further decrease in production is indicated in the figures for 1936-1937 which show a yield of but 8,172 crates of which 5,5o5 crales were produced from 76 acres in Palm Beach County.
The decline of the industry has been variously ascribed to competition from foreign growers, to the depletion of soil fertilizer and humus, and to the attack of pests. As early as 1921 the United States Bureau of Plant Industry became interested in the problems confronting Florida growers and in Farmers Bulletin No. 1 237, suggested methods by which pineapple growing might be re-established.
Nof until recent years has a rejuvenation of the industry been attempted. The renewal of plantings has been accompanied by a partial shift from the hardy Red Spanish variety, which formerly accounted for 90 per cent of all Florida crops. A few plantations exist in lower central Florida, but the most extensive fields lie along the east coast. One 85-acre plantation near Boynton is devoted to Abachis.
SELECTING A SITE
General Requirements. The pineapple is most successful ill regions of alternating dry and rainy seasons where an equitable temperature, averaging from 70 to 80c F., prevails. The annual rainfall should be 50 inches, or more if the soil is well drained.
Like most plants native to the tropics, the pineapple is susceptible to injury by frosts. Temperatures lower than 30 F. are likely to result in a decreased yield or complete destruction of the plant. The locality for the cultivation of pineapples, therefore, should be one which is known to be free, or practically free, from heavy frosts. Although the extreme southern portion of the Florida peninsula most nearly meets this condition, yet the most extensive plantings are found somewhat north of this area in localities where topographical conditions exert a benign influence on the climate.
Such factors as elevation and the presence of large bodies of water combine to furnish comparative freedom from dangerous temperatures. These factors occur conjunctively in several parts of the state, notably in the ridge section around Avon Par., and paricularly in the region adjacent to the Indian River, commonly known as the east coast pineapple belt. Plantations in the latter area are, with one important exception, located on an ancient sand dune 25 to 50 feet above the back country and extending in a narrow strip about two miles in width, for 150 miles.
Even within the limits of established plantation areas many sections are not adapted for successful planting. In addition to regional advantages, local conditions of air drainage and water protection should be thoroughly examined before determining on a particular site. Good roads and nearness to a shipping point or market are important. Besides the immedht; expense involved, long hauls over poor roads are likely to result in injury to the fruit. Accessibility to labor sources and community facilities are likewise desirable.
The Soil. It is the physical condition rather than the fertility of the soil which determines its adaptability for pineapples,
Drainage and aeration are essential; humus and plant foods may be made available by the grower. Pineapples are sensitive to excess lime, whch results in a yellowing of the leaves and the production of smaller, o.f-color fruit.
Most Florida plantings have been located on light, sandy soils. In their original state such soils are deficient in humus, a necessary environment for soil organisms so essential to successful pineapple culture.
Pineapples have been successfully grown on four general types of soil; scrub-pine land, "hickory scrub," flatwood pine-land, and hammock. Scrub-pine land, especially that found in the east coast belt, is chiefly composed of light, whitish sand. Beneath it, at a depth of five or six feet, is a subsoil of yellow sand. These are, for the most part, ridge lands and not generally retentive of moisture.
"Hickory scrub," somewhat Finer in texture than the scrub-pine, also contains more humus. It is likewise underlain by a subsoil of yellow sand at a depth of 5 to 10 inches. In the native state it supports a growth of hickory, oak, and other hard woods and is the type of soil preferred by experienced growers.
Flatwood pineland. usually level and damp, is composed of a whitish grayish sand underlain by a hardpan sub-soil which prevents the ready escape of water. It is found from Pinellas to lower Collier County and in eastern Palm Beach County. When properly drained it is satisfactory for pineapples. Practically all the plantings in Palm Beach County are on this type of soil.
Hammock land is richest in humus and fertility but it occurs in small tracts in those areas where pineapples are grown. In its original state this land is marked by vigorous growths of live oaks and cabbage palmettos.
Although 5o or more varieties of pineapples have been developed only a few have been found satisfactory for commercial cultivation in Florida. In former years the Spanish, or Red Spanish, was the most widely cultivated. The Smooth Cayenne, extensively cultivated for canning purposes in Hawaii, was second in importance and became a favorite for shed culture. Other varieties included the Black Ripley, Egypt.an, Golden Pernam-buco, and the Abachi. Breeding experiments produced a hybrid pink variety and from Natal came a small, but exceedingly sweet fruit which, it' was thought, might find appeal as an "individual pine." Of all these varities only three have considerable commercial importance.
The Spanish is probably the best variety for the average grower who practices open cultivation. It is hardier than other common varieties, and since it withstands adverse conditions of soil and climate to a greater degree, is easiest to grow. It also produces an abundance of slips, a trait which obviates many problems of propagation. The Spanish is inferior in quality to other varieties produced in the State but when carefully handled is much more satisfactory for shipping. The fruit is of medium size.
The Abachi is the leading variety in Palm Beach County which produces most of the pineapples grown on the east coast. Since the fruits attain great size and are of excellent quality, this variety is well adapted for special markets. It is, however, less hardy than the Spanish and requires great care and skill for successful production. The Abachi has two undesirable qualities. An abundance of slips are produced but frequently they grow so close to the fruit that it is difficult to secure them without damage. Another fault lies in the tendernesss of the fruit which must be harvested and handled with utmost care to avoid loss in shipping.
The Cayenne, known a the Smooth Cayenne because its broad leaves are free from spines, is a vigorous plant bearing large fruits of excellent flavor and quality. Its fruits, like those of the Abachi, are tender and require careful handling to prevent injury and loss in shipping. Increased acreage is difficult to obtain since the plant produces less than one slip and only one or two suckers.
The pineapple yields but few seeds and since they cannot be depended upon to reproduce the variety, are used chiefly for experimental purposes. Vegetative parts of the plant not only reproduce the variety but mature much more rapidly than plants developed from seeds. In commercial practice if is more prac-ical to use asexual methods in propagating. This is usually accomplished by means of slips and suckers, but ratoons, crowns, and even the stump of the plant may be used.
The stump is the common name for the stem of the plant which attains a height of from two to four feet. When used for planting purposes, they may be either half buried or entirely covered in furrows. Since the stump contains a large store of plant food it produces a vigorous growth. For propagating purposes the stump is serviceable chiefly on manganiferous soils.
In Florida, slips and suckers are the usual means of propagation. These miniature plants begin to develop before the fruit matures. Slips grow from buds which appear on the fruit stalk at the base of the fruit. Suckers develop in the axils of the leaves which are arranged spirally along the stem. Ratoons are suckers which develop from that portion of the stem which is below the ground.
The central part of the plant begins to die slowly after the fruit matures. Before this process is completed, the suckers which have been nourished by the parent plant, send out aerial root systems that penetrate the ground and sustain them. The ratoons likewise develop independent root systems.
Both the ratoons and the suckers will, if undisturbed, become full-fledged fruiting plants and, in turn, give rise to other ratoons and suckers which thus perpetuate the plantation. The number of suckers and ratoons produced vary. Usually not more than two should be left to bear fruit; others may be removed and used, together with slips and suckers, for new plantings.
In countries where the pineapple is canned, the crown is frequently used for propagating. The crown is the clustered leaf-growth which develops at the top of the fruif. Slips that appear at the base of the crown are known as crown slips.
Plant's grown from suckers selected at the proper stage of development will bear fruit in from 15 to 18 months, somewhat longer if slips are used. Plants grown from crowns require nearly two years to ripen their fruit.
Althought extravagant claims have been made regarding the superior qualifies of Cuban-grown slips, those selected from healthy Florida plants will give results equal to any foreign slips. Failure to secure profitable plantings is, in many instances, due to the indiscriminate use of propagating materials.
The use of all slips and suckers, regardless of size, form or condition of the parent plant, results in the perpetuation of many undesriable types of plants and fruits. There is also the probability that disease may be transferred to the new planting. Small malformed slips, and those taken from weak plants grow slowly, and rarely produce vigorous plants.
Care and judgment are essential in the selection of propagation materials. Well-developed slips and suckers taken from large productive parent plants are not only more resistant to disease but come into bearing sooner and produce fruit of greater size and quality.
The merits and characteristics of plants are most apparent when in bearing. Outstanding plants shou'd be marked at this time to insure the selection of suitable slips and suckers. Some convenient method, stakes or whitewash applied to a few leaves, should be adoped to identify healthy parent plants. If a sufficient number have not been marked, the needed slips should be collected only from the strongest remaining plants. In either case close supervision is advised if the desired improvement is to be obtained.
Maturity of slips and suckers for planting purposes is indicated by the brownish color of their stems. Choice specimens are broken off, thrown into the aisles, and later collected into piles. To encourage rooting in dry soils the hard basal end is cut off and the lower leaves are removed. Some Florida growers allow the cut end to cure before planting, but this practice has not shown any beneficial results.
Both slips and suckers may be collected two or three weeks in advance of planting. In Florida this work is usually done during August and planting continues until the middle of September to secure the benefit of autumn rains. The young plants are not seriously injured if the soil remains dry for some time; they take root and begin to grow when sufficient' rain falls.
Depending on size, slips are set two to four inches deep and suckers three to five inches, or to such a depth that the bud is approximately one inch above ground. In planting, some growers make a hole with a dibble, while others raise the soil slightly with a garden trowel and push the slip into the loosened earth.
Experienced growers prefer virgin land. Trees and other growth are cut down, and the roots grubbed out. All debris is burned but not on land to be planted, since fire destroys humus which in most cases is lacking in sufficient quantity. Pine stumps are sometimes left because they decay rapidly. After deep plowing, disking, and leveling, such land is ready to be marked off for planting.
The wide-bed system is commonly followed in Florida. A handdrawn marker is used to lay out the field in rows 22 inches apart. The marker is then drawn across the field at right angles to the first course to fix the distance between plants which, in this case, is also 22 inches. Each bed consists of six rows. The seventh row, left as an aisle between beds, is not planted. After three beds have been planted, two rows are skipped to serve as a roadway. This system requires approximately 10,000 slips an acre.
In the narrow-bed, or Cuban system, plants are set 10 inches apart in two 12-inch rows with a space of six feet between each bed. Larger fruits are produced where this system is followed, and wide spacing permits the use of cultivating machinery which eliminates much expensive hand labor. This system, however, has two disadvantages: a greater number of sunburned fruit are produced and because more soil is exposed to the sun there is rapid depletion of humus.
The use of flatwoods soil for the cultivation of pineapples was considered as early as 1916, but extensive commercial production on these lands is comparatively new, the largest development being in Palm Beach County.
Since flatwoods land is generally low, level and underlaid with hardpan, drainage is necessary. When the land is laid out a "ditch buster" is used to open drains 16Y2 feet apart and a sufficient depth to effect adequate drainage. The soil, thrown up by the ditcher, is leveled off with a device especially adapted for this purpose: a heavily constructed V-shaped frame attached to the axle of a carriage provided with two wheels spaced 16Yi feet' apart, or wide enough to follow the open drain bottoms. Cross ditches may also be opened at frequent intervals. These may be used for irrigation during prolonged dry periods.
Two hand-drawn markers are used to lay out the beds. One, with drags 20 inches apart, is used at right angles to the beds; the other, with drags 14 Yi inches apart, is drawn lengthwise to mark eight rows on the crown of each bed. The slips are planted at the intersection of the drag marks.
Single-wheel hand cultivators and shuffle hoes are the chief implements used in three or four annual cultivations to keep the fields clear from weeds. Pineapple leaves are brittle and injured leaves lose moisture to such extent that serious damage to the plant may follow.
To prevent sand blowing into and smothering the bud, young plants are protected by dropping a fablespoonful of cottonseed meal into the bud where it forms a hard core. The meal is sometimes mixed with an equal amount of tobacco dust and applied at the same rate to control attacks of the red spider, a practice known as budding.
Beginners are advised to follow fertilizing practices used by experienced growers in their immediate vicinit / and conduct experiments fo determine the combinations of ingredients which give the best results on their own soil. Tankage, cottonseed meal, and commercial "pineapple fertilizers," are used in varying amounts by successful growers. Some apply 1,500 pounds of standard fertilizer an acre in February, a like amount after harvest, and from 1,000 to 1,200 pounds of tobacco stems in early winter. Others use only tankage, 2,000 pounds an acre in one application after harvest followed by a dress.ng of tobacco stems a few months later.
For the first six months after the slips have been set out, nitrate of soda may be used but best results are thereafter secured by the use of organic sources of nitrogen. Tankage, cottonseed meal, and dried blood are recommended.
Experiments conducted at the Universitv of Florida Agricultural Experiment Station indicate that growing plants see red to thrive best when the formula was: nitrogen 4 per cent, phosphoric acid 6 per cent, and potash 6 per cent. For bearing plants a formula approximately 5-5-10 appeared to give the most satisfactory results, but the price of potash sources is a determining factor in its use.
The palatability of pineapples is not affected by the type of fertilizer applied fo the plants but with heavier applications of plant food larger fruits are produced. These contain less acid and more sugar than smaller ones.
The best sources of nitrogen are dried blood, blood and bone, cottonseed meal, and castor pomace. These materials, named in order of their usefulness, are not injurious to pineapple plants but "spike" may result from the us; of excessive quantities of cottonseed meal.
Nitrate of soda is rarely used on older plants because of its caustic action on the foliage, and the use of sulphate of ammonia is also extremely detrimental.
Bone meal is the most satisfactory source of phosphoric acid with Thomas slag a close second. Dissolved bone black, if genuine, is a good source of this element but acid phosphate did not give good results unless its application was followed by approximately 75o pounds of air-slaked lime an acre.
Magnesium potassium carbonate is the best source of potash. Sulphate of potash and potassium magnesium sulphate or double manure salts is almost as good. Kainit and muriate are detrimental fo the plants and are not recommended.
Protecting sheds for pineapple culture have been used in sections subject to frequent frosts, and in warmer sections because their partial shade protects against sunburn and conserves moisture which aids in producing larger and better flavored fruit.
Methods of construction vary but the usual plan calls for the placement of pine posts set 9 by 14 feet apart and braced with one-by-eight-inch stringers running the nine-foot way. Additional firmness is secured by providing additional narrower stringers across the nine-foot intervals. The height should be sufficient to permit ample clearance for men fo work. The roof may be of one by three material, 18 feet long, spaced three inches apart. For additional protection during heavy frosts the sides are enclosed with cloth or wood. Although shed culture, under favorable conditions, produces fancy, high-priced pineapples, many growers claim that the returns do not justify the large investment and upkeep.
HARVESTING AND MARKETING
A few pineapples are ripened throughout the year but the major part of the Florida crop is produced from June to mid-July. The fruit should be harvested by experienced men who can judge depth of color and ripeness. Pickers wearing heavy canvass gloves to protect their hands, break the fruit from the stems and toss it fo laborers who catch the fruit and place it in baskets or field crates which are loaded on trucks for transportation to the packing houses.
Pineapples are often harvested when fully grown but while still hard and green. Although these fruits develop the characteristic color of ripe pineapples they lack flavor and sweetness.
The ripening process of the pineapple differs from that of many fruits. Its sugar is secured from the starch in the stump and stem during ripening period. In the stage when the pineapple is commonly picked, the fruit contains approximately four per cent of sugar while the sugar content of fully ripened fruit ranges from 9 to 14 per cent. Therefore pineapples harvested in the immature state will not have the flavor of plant-ripened fruit.
Before fully ripe the pineapple turns a reddish yellow known as the "ruddy-ripe" stage, when it approaches the desirableness of the fully matured fruit and still posseses the firmness necessary for shipping. Little decay attends such shipments if the fruit is carefully handled and transported without delay in refrigerated cars.
Chief cause of decay in shipment, as shown by investigations of the Bureau of Plant Industry of the United States Department of Agriculture, are the punctures and bruises resulting from harvesting, packing, and shipping operations. The keeping qualities of pineapples, especially in warm weather, depends on the care with which they are handled and the length of time which elapses between picking and shipping. Pineapples should not be packed while damp, since moisture favors decay.
PINEAPPLES AT MATURITY
If pineapples must be picked while immature and shipped without refrigeration, they shou'd be fully grown and have a trace of green showing between the eyes. Immature fruit is not only poorly flavored bit does not stand shipment. Detailed handling and shipping information is contained in Pineapple Culture, a bulletin issued in 1938 by the Florida State Department of Agriculture.
YIELDS AND RETURNS
Yields and profits in the pineapple industry depend on climate, the skill and judgment of the grower, and market condition. Prior to 1917, 200 crates an acre was considered a good average yield but under intensive culture 300 crates and even more have been obtained. During the period when shed culture was at a peak, a return of SI3,000 was had from eight acres of Smooth Cayennes grown at Punta Gorda.
Since 1917, production and profits have been consistently low. According to Bulletin No. 39, published in 1938 by the Florida State Department of Agriculture, 1,375,655 plants produced 11,906 crates of pineapples in 1930. Allowing 10,000 plants to an acre, the average yield for the entire plantings was somewhat under 90 crates an acre. The Florida Agricultural Statistical Report of 1936-3 7 show that 122 acres under cultivation for that period yielded 8,172 crates, an approximate average of 67 crates an acre. The plantings on which these figures are based include both bearing and non-bearing acreage.
In former years plantings on virgin soil bore profitable crops for five years. On land free of disease this period was sometimes extended to 10 years. Since 1915, however, few fields have been profitable after the second or third crop was harvested.
Prior to the decline of the pineapple industry, attempts to replanf old fields were attended by indifferent results. Some were successful but few survived beyond a second crop; in many cases the first crop was disappointing. Since 1917, most re-plantings have failed chiefly because of the prevalence of wilt and the depletion of humus in the soil.
Most soils adapted for pineapple growing in Florida have an insufficient supply of humus. What little they have, even in the virgin state, is soon destroyed by open cultivation and exposure to the sun. Thus the soil is left in an impoverished condition and deficient in those organisms conducive to lusty vegetative growth. The supply of humus in the soil must be replenished to insure successful replantings.
Restoring Humus. Experiments conducted by the Bureau o? Plant Industry of the United States Department of Agriculture showed that Natal grass (Tricholaena rosea Nees) is the most satisfactory green manure for this purpose. It is not only the cheapest to plant but makes the quickest and heaviest growth. The seed is sown at the rate of 8 or 10 pounds fo the acre, usually in the fall when the moisture content of the soil favors germination.
Under ordinary conditions Natal grass will reseed itself from year to year. Two years are required before an effective amount of humus is made available; nearly twice that long where the soil is exceedingly poor.
Some growers object to the use of this grass because it becomes difficult to control, and substitute velvet beans and iron cowpeas. Crotalaria striata and Crotalaria spectabilis appear best suited for flatwood soil. In Palm Beach County where the largest flatwood planting is found, best results were obtained when the seed was sown during October or early November.
Like Natal grass, crotalaria reseeds itself each year. Since it frequently makes a thick stand five feet or more in height, a ''chopper" is used. This machine, resembling a huge roller, consists of two large, water-filled drums to provide the necessary weight, each drum equipped with wide sharp blades which cut and crush the crotalaria into the soil. The land can be worked later with a disc harrow if necessary.
PESTS AND DISEASES
The most destructive disease of pineapples in Florida is "red wilt," also known as wilt or blight. Its appearance in a field is marked by a change of color noticeable, at first, in the lower leaves which become a dull red. A diseased plant may resist the alt'ack for several months before the foliage assumes the characteristic reddish color and finally droops and dies. Unless the growing conditions are favorable, however, the progress of fhe disease is rapid and death of the plant follows swiftly after the first symptoms appear. Only a few scattered plants may show evidence of infection at first, but it spreads slowly until the whole plantation succumbs.
Red Wilt and Nematodes. For many years the cause of red wilt remained obscure, and various theories were advanced. It was found that either drought or the lack of fertilizer, might produce symptoms of wilt. When plants are attacked however, even in the early stages, the roots are found to be rol'ted.
As early as 1910 Hawaiian pineapple plantations were attacked by a disease known as wilt which caused the roots to rot. The agent, in this case, was supposed to be the mealy bug. The insect was known in Florida but the damage if caused was slight. A close study of the disease led to the belief that" red wilt was generally caused by the atfack of nematodes.
Nematodes(Heterodera radicicola) are microscopic, eellike worms common to the South, particularly in the light Florida soils adapted for pineapples. Boring into plant roots, they form galls or growths somewhat' similar to the nodules which appear on the roots of legumes when nitrogen fixing bacteria are active. A nitrogen-bearing nodule is generally spherical in shape and is attached fo, but not a part of, the root, while a nematode gall is an enlargement of the root itself. This enlargement is frequently club-shaped but various ofher forms have been noted.
Nematodes are parasites. They attack many plants and are difficult to derect in the pineapple field. Being a minute organism makes them inconspicuous and when they enter and destroy the fine feeding roots of the plant', decomposition begins and the root soon rots The characteristic roof galls are therefore not readily observed.
It is probable that nematodes may be carried from infested to non-infested areas in several ways. Their spread is aided by rains which wash soil from one field to another. Slips from affected fields may, if permitted to come in contact with the soil, carry the organisms to new plantings. Similarly, the feet of men or animals, and machinery or implements, which come in contact with soils containing nematodes may carry them to new locations. It has been observed that red wilt usually makes its appearance among plants close to roadways and, when new plantings are made adjacent to diseased areas, the plants closest to the diseased fields are the first to show symptoms of infestation.
Since numerous weeds common to Florida soils are hosts for nematodes it should not be assumed that virgin lands are free from them. Pineapple fields which have been abandoned because of their attacks are also likely to remain infested because the weeds that spring up when cultivation ceases become hosts for this parasite.
Although there is no way to save plants already affected by red wilt, efforts to control the growth and spread of nematodes in the soil have resulted in successful remedial measures. Small amounts of soil may be treated with such chemicals as chloropicrin or carbon bisulphide. One pound of six per cent formaldehyde dust to a bushel of soil is usuallly sufficient to kill all pests. Calcium cyanamid worked into the soil at the rate of one ton or more an acre is successful for field practice but not' practical because of the expense involved.
Before the cause of red wilt was known, it was supposed that slips, imported from distant areas where the disease was not prevalent, might prove resistant'. While importations were not successful, it was found that the Red Spanish was more resistant than the Smooth Cayenne.
During the experiments, it was discovered that certain useful plants were more or less immune to the attacks of nematodes. Investigations by the Bureau of Plant Industry showed that when such plants were permitted exclusively to occupy infested areas for several years, the pests could be practically starved out. Curiously enough, it was Natal grass, crotalaria, and iron cow-peas, crops recommended for the restoration of humus, that seemed best adapted for this purpose.
Natal grass and crotalaria are particularly useful for reconditioning abandoned fields. The former is effective on ridge soils when sown at the rate of 8 to 10 pounds an acre. This work can be done at anv season but conditions of soil moisture are usually more favorable during autumn months. Natal grass should be permitted to grow for two years at least and longer if the soil is markedly deficient in humus or if nematodes, at the end of that' period, are still observed.
In every case, tests should be made to determine the presence of nematodes before the grass is plowed under. Since they are susceptible to attacks by the organism, peppers are good test plants. If a number of the plants set at intervals throughout the field grow healthily and show no evidence of galls on their roots it is likely that the nematodes have been, for the most part, starved out.
The life of the replanting will be measurably increased If conditions conducive to a vigorous growth are provided: we'I-formed slips, clean cultivation to keep down weeds which may become hosts for nematodes, and precautions to reduce the chances of infestation spreading from diseased fields in the vicinity.
On the flatwoods soil of Palm Beach County, Crotalaria striata, sown as previously described, has been found satisfactory for the control of nematodes. Although not considered as resistant as Natal grass if is preferred for use on these lands. It appears to grow best when sown during October or verv early November.
Mealy Bugs. Although mealy bugs are not the serious pest in Florida that they are in other parts of the world, their prevalence in some sections has led to the adoption of defensive
measures somewhat similar to those used in Hawaii where they are reported to have caused considerable damage. In Florida, as in Hawaii, Che mealy bugs are apparently transported from one plant to another by ants which seem to feed on secretions from the bugs' bodies. The bugs cause damage by feeding on the buds and leaves of the pineapple plant".
Tobacco dust dropped into the bud of the plant affords some relief but oil emulsions have been found more effective. Large-scale growers having the necessary equipment may prefere to make their own emulsions. A satisfactory formula, used by Oscar R. Winchester, of Lake Worth, consists of two gallons of drain oil, two gallons of water and three pounds of kaolin. The kaolin is beaten into the oil for seven minutes with a high speed agitator. Water is added slowly and beating continues for four more minutes or until the oil is completely emulsified. The spray mixture contains one per cent oil, or two gallons of the emulsion in 100 gallons of water. It is applied at the rate of from 300 to 500 gallons an acre using a fine jet under 350 pounds pressure. The jets are directed at the bases of the lower leaves and washes out sand accumulations. No burning or other damage has been observed in the use of this emulsion.
Red Spider. The red spider, which often attacks the basal part of pineapple leaves, can be largely controlled by dropping tobacco dust into the buds. This pest is not considered a serious menace to growing plants but it is reported as having severely injured crated slips in shipment.
Soft Rot. Heavy losses in shipments of ripened fruit, especially during warm, humid weather, frequently result's from attacks of the fungus, Thielaviopsis paradoxa, which enters the fruit through the cut stem end or through cuts and bruises in the skin. Its attacks are characterized by a darkened, fermented, and decayed condition of the fruit', commonly known as soft rot. When conditions are favorable this fungus may pass rapidly from affected fruits to others in the same or near-by crates until the greater par of the shipment is valuless. Losses of this nature may be lessened by following the recommendations for harvesting and hauling fruit outlined on previous pages. Mature fruit, carefully handled, properly packed and promptly shipped, usually escapes serious damage.
Spike. Abnormal growth, marked by the production of thin, slender, elongated leaves, is known as "spike," or "long leaf." It' often appears among pineapples grown in highly cal-ciferous soils and these areas should be avoided when setting out a plantation. In some instances spike has been observed fo foilow excessive applications of fertilizer, especially phosphate, muriate of potash, and those containing inorganic sources of nitrogen.
Pineapple production is an enterprise requiring a great amount of skill, patience, and determination. Success involves knowledge, experience, and considerable capital. 11 is not a business which lends itself to a shoe-string start.
A preliminary investigation is essential. Before investing, the beginner should seek advice of State and County agricultural agencies, and consult established growers who are familiar with restoration methods and current problems. If is due to the tenacious efforts of such men that pineapple production in Florida, despite greaf handicaps, has survived the difficult period since
While the chief difficulty centers around the restoration of humus and the control of nematodes, there are others attracting the attention of experienced growers. One involves the use of certain gases to regulate to some extent the blooming period of pineapple plants in an effort to spread out the harvest season and thus eliminate the tendency to overstocking the market and the consequent lower prices. Another is concerned with attempts to control soft rot caused by attacks of the fungus, Thielaviopsis paradoxa. The solution of these problems has not yet been worked out but the experiments indicate that the pineapple industry, despite statistics, is not decadent.