Guava Cultivation
Scientific name: Psidium
guajava
Family:
Myrtaceae
"The guava tree, which gives so much and asks for so little, surely
deserves greater attention and cultivation."
Betty Molesworth Allen,
Malayan Fruits
Introduction
The
guava is normally cultivated for its fruits. However, guava fruit is
very delicate and highly perishable, making its marketing as a fresh
fruit very difficult. Present uses of guava are associated with the
processing into a wide range of canned products such as fruit slices in
syrup, guava jelly, jams, juice and nectar.
The potential for a
guava industry in Malaysia is excellent. Present tariff on imported
fruits is high and the public has developed the taste for local fruits
as substitutes. The guava is by far a more nutritious fruit than most
of the imported ones in terms of vitamin A and C content. Although
canned guava may lose about 50% of its vitamin C during heat
sterilization, the products still contain higher vitamin C than most
imported fresh fruits. Dehydrated guava juice powder was used as a
source of vitamin C to fortify rations of Allied troops during the
Second World War.
Varieties
A brief description of some of the promising varieties is given in
Table 1.
TABLE 1. Some
Promising Guava Varieties
| Variety |
Fruit size |
Appearance |
Flesh colour |
Seed |
Taste |
Products |
| GU
3 |
large |
Oblate,
grooved |
white |
abundant |
non-acidic |
fresh
fruit, juice |
| GU
4 |
medium |
elongate,
smooth |
white |
abundant |
non-acidic |
fresh
fruit, juice |
| GU
5 |
large |
smooth,
round |
red |
abundant |
acidic |
juice |
| Bentong
seedless |
medium |
irregular |
white |
absent |
non-acidic |
fresh
fruit, canned slices |
Cultivation
Soil and
Climate
Guava
can be grown in a wide range of soils, but does best in deep fertile
and well-drained loams. It can tolerate a wide range of pH from 4.5 -
8.2. Waterlogging, however, adversely affects the growth. Although
guava can tolerate drought conditions much better than other tropical
fruits, an annually even distribution of 100 - 200 cm of rainfall is
preferred for good growth. The tropical climate of Malaysia is
considered excellent for guava cultivation.
Field
Preparation
Forested
areas should be cleared of all shrubs and trees and the ground ploughed
in. In areas where the earth is extremely firm, deep cultivation using
tractor tines is recommended to break up the subsoil. Drains have to be
constructed where the water table is high.
The recommended
planting distance is 15' x 15'. This gives about 193 trees/acre. The
field should be limed and the planting distance measured out before
digging the holes. The holes should be at least 1.0 cu. ft. in size
depending on the firmness of the soil. In planting very large acreages,
tractor-operated augers should be used for digging the holes.
Propagation
Guava
is a cross-pollinated crop and as such, propagation by seeds will not
breed true. Vegetative propagation for this crop is relatively easy and
is a common practice in ensuring true-to-type progenies. Three
techniques are normally used for guavas, namely, cuttings, air layering
or marcotting and budgrafting.
Cuttings
This
method is simple in technique but variable in success. The shoots are
partially pruned of leaves and cut to lengths of six to eight inches.
The cuttings are inserted (proximal ends) into sand beds. The soil
medium should be kept constantly moist. Rooting should occur after 12
weeks.
Air layering
or marcotting
A
young shoot of about 1.0 cm in diameter is selected and a ring of the
bark tissue (3.0 - 4.0 cm wide) is removed at the base of the shoot.
Hormone dust is applied to the wound for induction of root formation. A
handful of moist top soil is then placed around the wound and a
polythene sheet and strings are used to secure the ball of soil around
it. Rooting occurs within three to five weeks in successful marcots.
The shoot can then be cut and the plastic sheet removed before
planting. In Malaysia, marcotting for guava has been limited in success
and is not commonly used.
Budgrafting
This
method is most commonly used under local conditions. The advantage of
this is that a higher percentage of success can be obtained and more
plants can be produced from limited parental materials. However, there
is a need to prepare the rootstocks for budding. Guava seeds can be
easily germinated in 8" x 12" perforated black polybags for this
purpose. Three seeds are sown into each bag to ensure that at least one
plant will survive. The plants are ready for budding when the stem at
the base is as thick as a pencil.
A 1.0 cm x 3.0 cm incision is
first made on the bark of the rootstock and the flap gently peeled
away. A similar size bud patch from the scion is then inserted into the
cut. The scion patch is firmly secured with transparent budgrafting
tapes.
The tapes are removed three weeks after grafting. In
another three weeks, the grafts are inspected and where the bud patch
survives, the rootstocks are cut back or 'dehorned' to about 4.0 - 5.0
cm away from the bud patch. This is to stimulate the bud to 'break'.
The plants can be field transplanted two or three months later. Lateral
shoots originating from the rootstocks should be removed in the
meanwhile.
Field Management
Fertilizer
The
fertilizer schedule for guavas suitable for local conditions is
indicated in Table 2 (after Kementerian Pertanian dan Pembangunan Luar
Bandar). The compound fertilizer recommended is a 28:9:9 composition of
N:P:K. In addition, guavas have been known to respond well to farmyard
manure and composts, and an application of 50 lb. per acre prior to
planting is recommended.
Fertilizer application should
preferably be made every four months to coincide with the stages of
heavy nutrient demand. There are normally three peak harvests over one
year and it is recommended that the timing of the application be
scheduled at one month prior to the new flush of flowering. The dosage
of fertilizer per annum must be equally split into three parts for each
application.
TABLE 2.
Fertilizer Application for Guava Over 15 Years
| Plant age |
lb/tree/annum |
N/tree/annum (lb.) |
P,K/tree/annum (lb.) |
| 1 |
1.0 |
0.28 |
0.09 |
| 2 |
2.0 |
0.56 |
0.18 |
| 3 |
3.5 |
0.98 |
0.32 |
| 4 |
4.5 |
1.26 |
0.41 |
| 5 |
5.5 |
1.54 |
0.50 |
| 6 |
6.5 |
1.82 |
0.59 |
| 7 |
7.5 |
2.10 |
0.68 |
| 8 |
8.5 |
2.38 |
0.77 |
| 9 |
9.5 |
2.66 |
0.86 |
| 10 |
11.0 |
3.08 |
0.99 |
| 11 |
13.0 |
3.64 |
1.17 |
| 12 |
15.0 |
4.20 |
1.35 |
| 13 |
17.0 |
4.76 |
1.53 |
| 14 |
19.0 |
5.32 |
1.71 |
| 15 |
21.0 |
5.88 |
1.89 |
Training and
Pruning
It
is an important practice to train the trees into establishing a
desirable bush-shaped canopy on a single erect stem to control the
height and spread of the tree for convenience of harvesting and also to
increase the size and quality of the fruits. Pruning is done from time
to time on water shoots and suckers arising from the base of the
rootstocks, as they are not of the desired material.
Guava is
best trained in an open-centre system. The main erect trunk of the
young plant is cut back to about 50 cm above the ground at a point just
below a bud. Three or four shoots (laterals) are permitted to grow from
the main stem just below the cut end and they will form the basis of
future branches. These laterals are allowed to develop to about 25 - 30
cm long and then pruned, inducing production of the secondary branches
which will carry most of the fruits. Guavas trained on the open-centre
system in India have significant increase in yield and fruit quality as
compared to unpruned trees.
Yield
Budgrafted
trees often begin to bear about six months after transplanting in the
field. The trees at this stage should not be allowed to be overly heavy
in bearing, as this will have adverse effects on their vegetative
development in the later years. Pruning of fruitlets and flower buds is
recommended for reduction of the crop in the first year of bearing. In
the second and subsequent years of cropping however, fruit thinning is
not necessary. Under favourable conditions, the yield increases until
the trees reach full bearing at eight years and from then on,
production continues for fifteen years or more.
Yield taken on
two-year old trees in Serdang of three varieties of guava indicated
that there are three main peaks in the annual cropping pattern.
Although generally regarded as a non-seasonal crop, the yield in
between the peaks are low and often negligible. Preliminary
observations showed that flushes of flowers appear at the decline of
each peak of bearing, the fruits of which contribute to the following
season's harvest.
The most promising varieties are GU 4 and GU
5. Two-year old trees of these varieties produce fruits close to 10
tons/ha/year. GU 3 yields only about half as much. In addition, the
seasonality of fruit production for GU 5 has a wider spread than the
other varieties. indicating that fruits of the GU 5 are more often
available. This is an important criterion in considering cultivars for
processing to ensure continuity of supply of fruits to the factory.
Diseases and
Pests
Fruit Scabs
This
disease on young guava fruits is especially common on trees which are
poorly managed and are weed infested. Round, brown and raised corky
scabs caused by Pestalotia
sp. are found on the surface of the fruit, giving it a mottled,
unattractive appearance. In less severe cases, the fungi does not cause
very extensive damage to the fruit and it may still be consumed after
removal of the skin. In serious infestations, however, the young fruits
remain underdeveloped and may eventually abort.
Keeping weeds under control is an effective means of reducing the
incidence of this disease.
Algae 'rusts'
The
symptoms of the disease appear mainly on the leaves as reddish-brown,
round, powdery colonies. This occurs most frequently in damp,
poorly-ventilated areas where weed management is poor. The causal agent
is the Cephaleuros algae and may not be the cause of alarm if the
infestation is slight. However, in more severe cases, premature leaf
fall will occur, resulting in a marked decrease in yield.
Regular
pruning of the dense foliage and effective weed control will provide
ventilation that checks the incidence of the disease. Coprantol with
Arbolineum (white oil) mixed in the proportion of 1:80 sprayed at 0.2%
bi-weekly until infestation disappears is recommended.
Oriental
fruit fly
The
fruit fly is the most important pest that results in insurmountable
damage on guava fruits. The species that is commonly found in Serdang
is Dacus dorsalis
Hend. Another damaging fruit fly, Anastrepha
striata, which is widespread in Surinam and some parts of
the United States has not been recorded in Malaysia.
The
damage is caused by the adult female flies, which deposit the eggs in
the maturing fruits. The point of deposition is noticeably marked by
the small dark depressions on the surface of the fruits. Development of
the larvae when the fruit ripens causes extensive damage and soft rot
of the fruit.
To control the infestation, in part at least,
fruits should be picked green, when they are still very firm. It is not
probable that the fruits are infested at this stage, but even if so,
immediate processing will destroy the eggs before the larvae can
develop. Over-ripe fruits should not be littered in the orchards as
these act as food base for the larvae development of the flies.
Sanitation of the orchard at all times is important in reducing the
population of the pest. Fenthion (Lebacid) at 0.1% sprayed four weeks
before fruit ripening gives very good control.
Spilonota
damage
The
larvae of this Lepidopteran feed on young shoots and leaves and form a
webbing at the terminus of the shoot before maturing into the adult.
The infestation is observed to be seasonal and can be extensive if
uncontrolled.
Rogor 40 at 0.1% concentration is very effective in the control. A
bi-weekly spray until infestation disappears is recommended.
Mealy bugs
Mealy
bugs are whitish, fluffy insects that cause damage to young supply
shoots and leaves by sucking the sap, resulting in the dieback of the
tender shoots. The damage is not normally alarming. Control however,
can be effected with the use of Malathion or Arbolineum at 0.1% spray.
Helopeltis s. damage
The
symptoms of damage are angular necrotic patches on leaves and shoots
caused by the secretion of insect toxins in the feeding punctures.
Control measure using Rogor 40 is very effective.
Fruit
'ringing'
The
symptom is a dry rot appearing as a band around the lower half of the
fruit, often accompanied by splitting of the skin. Pestalotia has been
isolated from the infected area, but this was believed to be a
secondary infestation. There appears to be some varieties, particularly
an Indonesian cultivar with pyriform fruits, which are very susceptible
to this disorder. The cause of this phenomenon is not clearly
understood at present, but is currently under investigation. The
contemporary belief is that it is caused by water stress.
References:
Allen. B.M. (1967) Malayan Fruits. Donald
Moore. Singapore. 245 pp.
Chan, Y.K. and T.S. Tee (1976). The cultivation
of guava (Psidium guajava
L.) Malaysia. Mardi Report No. 45. 23 pp.
Kementerian Pertanian dan Prembangunan Luar
Bandar (1975). Report of the Committee on Fruits and Vegetables. Vol.
1. 246 pp.
Mallik, P.C. and D.L. Singh (1960). Deficiency
symptoms of nitrogen. phosphorus and potassium in guava. Indian Agric.
4: 44-9
Singh, R.G. and S.N. Dafe (1971). Micronutrient
deficiency in Mango (M.
indica L.) and guava (P.
guajava L.) Allahabad Fmr. 45 : 479-83.
Tingwa, P.O. and S. Abbadi (1968). The
vegetative propagation of tropical guava (P. guajava L.) in
the Sudan. Sudan Agric. J., 3: 12-20.
Van Brussel. E.W. and G. Van Vreden (1969).
Studies on the biology, damage caused and control of the guava fruit
fly, Anastrepha striata
in Surinam. Surinam Landb. 16: 110-22.
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