From the Archives
of the Rare Fruit Council of Australia
by Allan King
The Sugar Apple
Scientific
name: Annona
squamosa
Family:
Annonaceae
The Sugar Apple, or what is more commonly
known in Australia as the
Custard Apple is native to Central and South America, but now is common
throughout the world's tropical areas. Of the Annonas, it is the
most widely-distributed species.
It
is a small semi-deciduous tree reaching 4 to 6 metres in height. The
bark is light-brown and of an even texture. The tree often produces
multiple stems and responds well to pruning.
The leaves, which
are from 50 to 100 millimetres long, are light green and smooth in
texture. The flowers, which are produced on the woody stems and
branches, are singular or in clusters of two to four. They are
greenish-yellow in colour, about 20 millimetres long, the three, thick
outer petals are oblong, rounded at the ends; the inner petals are
minute, ovate. A highly purgative tea can be made from the roots and a
mildly laxative and tonic tea from the leaves. The crushed leaves and
seeds are considered to have insecticidal properties.
The fruit
is highly esteemed in many countries and ranks amongst the finest
dessert fruit in the world. It is round to heart-shaped, between 50 -
125 millimetres in diameter and pale green in colour. The fruit is what
is technically known as a syncarp, which means that it is a compound
fruit consisting of numerous fleshy carpels which are fused together
within the skin. Many of these carpels contain brown seeds about the
size of an average bean.
The pulp is of a smooth custard-like
texture and the flavour is excellent. It is delicate, sweet, subacid,
and tastes similar to blanc-mange. The Sugar Apple or Custard apple as
we know it, is rarely seen on our local markets, and should not be
confused with the Atemoya custard apple which is grown commercially in
N.S.W. and Queensland and often available here. The Atemoya is a larger
fruit, has less seeds and is more aromatic in flavour.
The Sugar
Apple is a common sight in many Top End gardens and has been here since
early settlement. Because the ripe fruit is relished by some of our
native animals, namely birds, flying-foxes and possums, it is now
naturalized here, due to the wide spreading of seed. The main crop
comes late wet season, however the tree will continue cropping
throughout the year if watering is maintained. The fruit should be
picked before it has ripened fully, as in the later stages, it ripens
very quickly, and thus gives the birds the upper hand.
After
flowering, as the fruit forms, the many bumps which cover the carpels
and form the skin, become more and more defined. When the fruit reaches
full size, the green bumps become separated by a creamy-yellow colour
between them. The fruit is ready for harvest when it reaches this stage
and when it feels slightly spongy in comparison to previously being
rock hard. Once picked, the fruit should be left in a cool place to
ripen, then it becomes soft and is ready to eat within a couple days.
If desired, this process can be slowed down by refrigeration.
This
tree is a very hardy species, it can withstand drought for a
considerable period of time, but cannot withstand frost or long cold
periods. It is a good choice for our climate and termite attack is
rare, although some instances have been recorded. It is tolerant of
most soil conditions, although like most trees, it succeeds best in
rich, sandy loam, and likes to be well-drained. The tree prefers an
'open forest' situation, not being over-shaded, and an annual light
pruning is beneficial. Application of manure and fertiliser assists
cropping and is essential in attaining large fruit. Insect pests which
affect the sugar apple are few and usually only occur if the tree is in
a poor state of health or growing in a position which is adverse to its
requirements.
Most common of these pests are Whitefly and
Mealybugs. Whitefly is seen under the leaves in the pre-adult stage,
the small, black, scale-like creatures are only 3 millimetres long and
have scattered soft spines on their upper surface. Mealybugs are white,
fluffy, from 3 to 6 millimetres long and covered with a waxy secretion.
They are yellow when squashed, and if there are only a few present this
is the best method of control. Both Whitefly and Mealybugs can be
controlled by spraying with a mixture of Pyrethrum and White Oil, or
preferably Summer Oil, and the operation should be done in the late
afternoon to prevent leaf-burn. Squirting the undersides of the leaves
with the hose is an effective method of deterring these sort of insects.
Sugar
apples are mostly propagated by seed, although some grafted cultivars
do exist. Seedlings can fruit in 2 to 3 years and such a hardy tree
with such delicious fruit should find itself in every Top End home
orchard.
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