In Mexico and Central America the cashew is common on the seacoast but is rarely found at elevations higher than 3000 feet. At altitudes of 5000 or 6000 feet the climate appears to be too cool for the tree.
The English name cashew is an adaptation of the Portuguese caju. The latter was taken by the earliest settlers in Brazil from the Tupi name acaju. In the Spanish-speaking countries of tropical America the usual name is maranon, presumably from the Brazilian state of Maranhao. The name pajuil is used in Porto Rico, while in Guatemala the similarity of the cashew to its relative the mombin (Spondias Mombin) is recognized in the common name jocote maranon (the mombin being called simply jocote). In India the form kaju (gajus in the Malayan region) has appeared, in addition to a number of names not derived from the American caju. In French the cashew-apple is called pomme d'acajou, and the nut noix d'acajou. The latter is termed castanha (chestnut) in Brazil.
In many regions the nut is more extensively used than the apple or fleshy portion. In Brazil this is not the case.
The cashew-apple is soft, juicy, acid, and highly astringent before maturity, retaining sufficient astringency when fully ripe to lend it zest. Owing to its remarkably penetrating, almost pungent aroma, the jam or sweetmeat made from it possesses a characteristic and highly pleasing quality. It is also used to supply both a wine and a refreshing beverage, similar to lemonade, which the Brazilians know as cajuada. The wine, which is manufactured commercially in northern Brazil, retains the characteristic aroma and flavor of the fresh fruit. The preserved fruit in various forms also is an article of commerce.
In several countries the cashew-nut is produced commercially and exported to Europe and North America. According to Consul Lucien Memminger, shipments to the United States from the Madras Presidency in India during the year 1915 totaled 2288 cwt., valued at $28,063. "About 15,000 cwt. of these nuts are now exported in an average season to England, France, and America, the principal port of shipment being Mangalore."
The cashew-nut is kidney-shaped, and about an inch in length. The soft, thick, cellular shell or pericarp incloses a slightly curved, white kernel of fine texture and delicate flavor. To prepare the nuts for eating, they are roasted over a charcoal fire. The shell contains cardol and anacardic acid substances which severely burn the mouth and lips of any one who attempts to bite into a fresh nut. Since these principles are decomposed by heat, the roasted nut can be eaten without the slightest inconvenience or danger. The kernel is said to contain: fats 47.13 per cent, nitrogenous matter 9.7 per cent, and starch 5.9 per cent. An analysis made in Hawaii by Alice R. Thompson showed the presence of protein to the amount of 14.43 per cent, ash 2.58 per cent, fat 4.56 per cent, and fiber 1.27 per cent.
The cashew is not particular in regard to the soil on which it grows, but it is intolerant of frost and can only be cultivated successfully in regions where temperatures much below the freezing point are rarely experienced. An account of its culture in southwestern India is given in the Daily Consular and Trade Reports for November 3, 1914:
"Cashew-nut trees can be grown successfully on any soil. They thrive in sandy places as well as on stone, and are not fastidious in point of soil, but are generally grown where no other crop can be produced. In this district there are many sand hills, especially below Ghats, which are utilized for this crop. Along seacoasts which are exposed to severe gusts of wind, the plants never attain the form of a tree, but keep along the ground, producing small branches.
"Seeds . . . are usually planted in the month of June, at a distance of about 15 feet each way. In many cases this distance proves to be insufficient. The plants are watered the first year only. No other care is taken of them. The plantation is usually inclosed by walls.
"The plants begin to bear from the third year and continue till the age of about fifteen, at which stage the trees exude a gummy substance in large quantities and then die."
In other regions the trees live to a greater age than fifteen years. Reports from many parts of the world indicate that they may come into bearing the second or third year. P. W. Reasoner recommended the cashew for cultivation in northern greenhouses, because of its habit of bearing at an early age.
In Brazil the cashew flowers in August and September and ripens its fruit from November to February. In southern India the flowering season is December and January, and the fruit ripens in March. An Indian writer estimates the yield of a mature tree at 115 to 150 pounds of fruit yearly. "To get one maund (28 pounds) of kernels about 1 1/2 candies (115 pounds) of seed nuts are required."
Very few pests have been reported as affecting the cashew. Father Tavares 1 mentions a fungus parasite which attacks the branchlets, leaves, and flowers at Bahia, Brazil. The red-banded thrips (Heliothrips rubrocinctus Giard.) sometimes attacks the tree in the West Indies. H. Maxwell-Lefroy mentions two other species of thrips which have been found on the cashew in Mysore, India : these are Idolothrips halidaji Newm. and Phloeothrips anacardii Newm. (?).
Seedling cashew trees differ in the character and quantity of fruit they yield. In Brazil the trees which produce the largest and finest fruits are distinguished with varietal names. Some of these trees acquire local reputations.
Recently P. J. Wester has shown that the cashew can be shield-budded. By employing this method, it is easily possible to propagate choice varieties originating as chance seedlings. The reader is referred to Wester's publication "Plant Propagation in the Tropics," 2 one of the most valuable contributions which have been made to tropical pomology.
The method of budding the cashew is essentially the same as that described in the chapter on the avocado. Wester says in brief: "Use nonpetioled, mature budwood which is turning grayish; cut the bud l½ to 1¾ inches long; insert the bud in the stock at a point of approximately the same age and appearance as the cion."