From the Manual Of
Tropical And Subtropical Fruits
by Wilson Popenoe
The Cashew
Anacardium occidentale L.
The Brazilians are the only people who fully appreciate the cashew.
Father J. S. Tavares, whose studies of Brazilian fruits are probably
the most exhaustive as well as the most interesting which have been
published, says of this tree: "It furnishes food and household remedies
to the poor, a refreshing beverage to the sick, a sweetmeat for tables
richly served, and resin and good timber for industrial uses."
The
readiness with which the cashew grows and fruits in a semi-wild state
has kept it from receiving the horticultural attention which other and
more delicate species have enjoyed. In nearly all regions where it is
grown, it is more common as a naturalized plant than in the fruit
garden. It does not object to such treatment, but multiplies rapidly,
grows vigorously, and yields abundantly of its handsome fruit.
To
see the cashew at its best, one must visit the markets of Bahia or some
other city of the Brazilian coast. Here, during the short season in
which they ripen, immense heaps of cashews are piled up on every side.
Its brilliant shades of color, varying from yellow to scarlet, and its
characteristic and penetrating aroma combine to make this one of the
most enticing of all tropical fruits.
The cashew is a spreading
evergreen tree growing up to 40 feet in height. One of the early
voyagers, Father Simam de Vasconcellos, speaks of it as "the most
handsome of all the trees of America," for which extravagant statement
Father Tavares takes him to task. The cashew cannot fairly be called
handsome; indeed, it is oftentimes awkward or ungainly in habit, with
crooked trunk and branches. The leaves, which are clustered toward the
ends of the stiff branchlets, are oblong-oval or oblongobovate in form,
rounded or sometimes emarginate at the apex, and acute to cuneate at
the base. They vary between 4 and 8 inches in length, and 2 and 3
inches in breadth.
FIG. 22. Foliage, flowers, and fruit of the cashew (Anacardium occidentale).
The
kidneyshaped seed (properly speaking, the fruit) contains an edible
kernel of delicious flavor, while the fleshy portion (fruit-stalk)
above it is filled with aromatic juice, and may be used in many ways.
The
flowers are produced in terminal panicles 6 to 10 inches long. The
cashew, like the mango, is polygamous; that is, some of the flowers are
unisexual (staminate) and others bisexual, both types being produced on
the same panicle. The calyx is five-partite, the corolla 1/3 inch
broad, with five linearlanceolate, yellow-pink petals. The stamens are
usually nine in number, all fertile. The ovary is obovoid, with the
style placed to one side.
The fruit is peculiar. The part which
would be taken for the fruit at first glance is in reality the swollen
peduncle and disk, while the fruit proper is the kidney-shaped
cashew-nut attached to its lower end. The fleshy portion may be termed
the cashew-apple, in order to distinguish it from the true fruit, or
cashewnut. It differs in size, being sometimes as much as 3i inches in
length, while it may be less than 2 inches. The surface is commonly
brilliant yellow or flame-scarlet in color. The skin is a thin
membrane, easily broken ; the flesh light yellow in color and very
juicy. The kidney-shaped nut which is attached to its lower end
contains the single oblong seed.
The cashew was formerly
thought, by some writers at least, to be indigenous both in America and
Asia. It has been shown, however, that it was originally confined to
America, whence it was carried to Asia and Africa by early Portuguese
voyagers. Jacques Huber 1 considered it indigenous on
the campos (plains) and dunes of the lower Amazon region and the north
Brazilian coast in general. It spread very early to other parts of the
tropical American seacoast, and probably was introduced into the West
Indies by the Indians who reached those islands from the South American
mainland before the arrival of Europeans. Gabriel Soares de Souza, one
of the earliest chroniclers of Brazil, found the tree growing both wild
and cultivated on the coast of Bahia in the sixteenth century. He
mentions a "fragrant and delicious wine" which the Indians prepared
from the fruit.
At the present time the cashew is common on the
mainland of tropical America from Mexico to Peru and Brazil. It is
abundant also in the West Indies. In Africa it is found on both the
east and west coasts, and in Madagascar. In southern India it has
become thoroughly naturalized in many of the coastal forests. It is
grown in the Malay Archipelago, and is said to be abundant in Tahiti.
In Hawaii it is not very common.
Regarding its occurrence in India, Dymock, Warden, and Hooper (Pharmacographia Indica) say:
"It
was not known in Goa A.D. 1550; but Christopher a Costa saw it in
Cochin shortly after this. ... In 1653 only a few trees existed on the
Malabar coast; since then it has become completely naturalized on the
western coast, but is nowhere so abundant as in the Goa territory,
where it yields a very considerable revenue. It is planted upon the low
hilly ridges which intersect the country in every direction, and which
are too dry and stony for other crops. The cultivation gives no
trouble, tne jungle being simply cut down to make room for the plants."
In
the United States the culture of this tree is limited to the coast of
Florida, south of Palm Beach and Punta Gorda, approximately. There are
sturdy fruiting trees both at Palm Beach and Miami. In California all
experiments up to the present time have indicated that the climate is
not warm enough for it.
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 mombiri) 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 2 mentions a fungus parasite which attacks the branchlets, leaves, and flowers at Bahia, Brazil. The redbanded 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 1 1/2 to 1 3/4 inches long; insert the bud in the
stock at a point of approximately the same age and appearance as the
cion."
1 Boletim do Museu Goeldi, 1904.
2 In Broteria, xiv, January, 1916.
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