The fruit is eaten in many ways, out of hand, sliced with cream, stewed, preserved, and in shortcakes and pies. Commercially it is used to make the well-known guava jelly and other products. When well made, guava jelly is deep wine-colored, clear, of very firm consistency, and retains something of the pungent musky flavor which characterizes the fresh fruit. In Brazil a thick jam, known as goiabada, is manufactured and sold extensively. A similar product is made in Florida and the West Indies under the name of guava cheese or guava paste. An analysis at the University of California showed the ripe fruit to contain: Water 84.08 per cent, ash 0.67, protein 0.76, fiber 5.57, total sugars 5.45 (sucrose none), starch, etc., 2.54, fat 0.95.
The guava succeeds on nearly every type of soil. In Cuba it does well on red clay, in California it has been grown on adobe, and in Florida it thrives on soils which are very light and sandy. While not strictly tropical in its requirements, it can scarcely be called subtropical. It is found in the tropics at all elevations from sea-level to 5000 feet, and it withstands light frosts in California and Florida. Mature plants have been injured by temperatures of 28° or 29°, but the vitality of the guava is so great that it quickly recovers from frosts which may seem to have damaged it severely. Young plants, however, may be killed by temperatures of only one or two degrees below freezing. As regards moisture, writers in India report that the guava prefers a rather dry climate.
The plants may be set from 10 to 15 feet apart, the latter distance being preferable. They should be mulched with weeds, grass, or other loose material immediately after planting. In certain parts of India, where guava cultivation is conducted commercially on an extensive scale, it is the custom to set the plants 18 to 24 feet apart. Holes 2 feet wide and deep are prepared to receive the trees. Occasionally the soil is tilled and once a year each plant is given about 20 pounds of barnyard manure. During the dry season the orchard is irrigated every ten days. Very little pruning is done.
Seedling guavas do not necessarily produce fruit identical with that from which they sprang. It is the custom in most regions to propagate the guava only by seed, but choice varieties which originate as chance seedlings can be perpetuated only by some vegetative means of propagation, such as budding or grafting.
Although the seeds retain their viability for many months, they should be planted as soon after their removal from the fruit as possible. They may be sown in flats or pans of light sandy loam and covered to the depth of 1/4 inch. When the young plants appear they should not be watered too liberally. After they have made their second leaves, they may be transferred into small pots. Since they are somewhat difficult to transplant from the open ground, they had better be carried along in pots until ready to be planted in the orchard. The proper season for planting varies in different regions; in India it is said to be July or August; in California it is April and May; while in Florida October and March are good months.
Both shield-budding and patch-budding are successful with the guava. Shield-budding is the better method of the two. P. J. Wester, who says that the guava was first budded, so far as known, in 1894 by H. J. Webber at Bradentown, Florida, describes the method in the Philippine Agricultural Review for September, 1914. He states that budding should be performed in winter. While it has been done successfully as late as May, the months from November to April are the best (in the southern hemisphere the season would, of course, be at the opposite time of year). The stock-plants should be young; it is best to use them just as soon as they are large enough to receive the bud. When inserted in old stocks the buds do not sprout readily. The method of budding is the same as that described for the avocado and mango. The bud wood should be so far mature that the green color shall have disappeared from the bark. The buds should be cut 1 to 1 1/2 inches long.
Patch-budding has been successful in California when large stock-plants have been used. They should have stems 1 inch in diameter, and the buds should be cut 1 1/2 inches in length, square or oblong in form. Propagation by cuttings is also possible if half-ripened wood is used and bottom-heat is available.
A simple method of propagation, which may be employed when it is desired to obtain a limited number of plants from a bush producing fruits of particularly choice quality, is as follows: With a sharp spade cut into the soil two or three feet from the tree, severing the roots which extend outward from the trunk. Sprouts will soon make their appearance. When they are of suitable size they may be transplanted to permanent positions. They will, of course, reproduce the parent variety as faithfully as a bud or graft.
The guava is a heavy bearer and ripens its fruit during a long season. In some regions guavas are obtainable throughout the year, though not always in large quantities. Seedlings come into bearing at three or four years of age; budded plants may bear fruit the second year after they are planted in the orchard. Indian horticulturists state that the plants bear heavily for fifteen to twenty-five years, and thereafter gradually decline in production. The guava is not a long-lived plant, but may live and bear fruit for forty years or more. The season of ripening in India is November to January; in Florida and the West Indies it is in late summer and autumn.
The guava is subject to the attacks of numerous insect and fungous enemies. The list of scale insects injurious to it is a particularly long one, including numerous species belonging to the genera Aspidiotus, Ceroplastes, Icerya, Pseudococcus, Pulvinaria, and Saissetia. All of these can be held in check by the usual means, i.e., spraying with kerosene emulsion or some other insecticide, but little attention is given to this matter in most tropical countries. The fruit-flies, including species of Anastrepha, Ceratitis, and Dacus, cause serious trouble in many regions. It is said that 80 per cent of the guavas produced in Hawaii have in some seasons been infested with the larvae of the Mediterranean fruit-fly (Ceratitis capitata Wied.). The guava fruit-rot, a species of Glomerella, is a common fungous disease in some places. There are other pests, some of them serious, which the guava-grower may have to combat.
Within the species there evidently exist more or less well-defined races, each of which includes many seedling variations. Of true horticultural varieties, propagated by cutting or grafting, there are as yet practically none. The so-called varieties listed in different regions are presumably seedling races. Indian nurserymen distinguish a number of forms, such as "smooth green," "red-fleshed," Karalia, Mirzapuri, and Allahabad. In the United States, seedlings are offered of the Allahabad guava, and of forms termed Brazilian, Peruvian, lemon, pear, smooth green, snow-white, sour, Perico, and Guinea. The number of such forms which could be listed is considerable. The Guinea variety, a white-fleshed, sweet-fruited guava with few seeds, has been propagated in California by budding, but it has not been planted extensively.