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RUBBER
(Hevea brasiliensis)
Rubber
can be grown from sea level up to an altitude of 500
m in areas of well distributed annual rainfall of not
less than 200 cm and a warm, humid equatorial climate
(21-35ºC). The soils of main rubber tracts in India,
confined to a narrow belt on the west of the Western
Ghats, running parallel to it for about 400 km, are
mostly laterite in nature. Well-drained alluvial and
red loam soils are also suitable for rubber cultivation.
Propagation
(i)
By clonal seeds collected from approved poly-clonal
seed gardens in the country and abroad.
(ii) By budded plants.
(iii) By tissue culture plants.
The
clones may be planted as follows:
Category
1
Budded clone of RRII 105 and PB 260 may be planted
to cover only 50% of the total area of any estate
or small holding.
Category
2
Budded clones of RRIM 600, Gl 1, PB 28/59, PB 217
and RRIM 703. Three or more of these may be planted
to cover up to 50% of the total area of any estate
or small holding.
Category
3
Budded clones of RRII 5, RRII 203, PR 255, PR 261,
PB 235, PB 280, PB 311 Tjir 1, PB 86, GL 1, PR 107,
RRIM 605, RRIM 623, RRIM 628, RRIM 701, PB 6/9, PB
5/51, RRII 118, RRII 208 and polyclonal seeds of approved
sources may be planted in very small scale not to
exceed 15% of the total area in aggregate.
Nursery
Nurseries
are maintained for raising seedlings, budded plants
and bud wood. Beds are prepared 60-120 cm wide and
of convenient length with path ways laid in between
to facilitate manuring, watering, weeding etc.
Spacing
in the nursery according to the type of planting materials
is as follows:
For
raising seedling stumps: 23 x 23, 30 x 30 or 34 x
20 cm
For budded stumps: 30 x 30 cm
For stumped buddings: 60 x 60 cm
For bud wood nurseries: 90 x 90 or 60 x 120 cm
Intensive
care may be exercised in the nursery than in the field
for the rapid production of healthy planting materials
by adopting proper mulching, weeding, manuring, pest
and disease control measures.
Planting
techniques
Rubber plantations in India are mostly situated on
sloppy and undulating lands. On such lands and hilly
areas, adequate soil conservation measures should
invariably be resorted to.
Planting
distance
The planting density recommended is 450 to 500 plants
per hectare.
Pitting
and refilling
The standard pit size recommended is 75 x 75 x 75
cm. Slight variations may be made depending on the
nature of the soil. While digging the pit, topsoil
should be placed on one side and subsoil on the other
side. Filling should be done with topsoil as far as
possible. Apply manure thoroughly mixed with the top
20 cm of the soil in the pit.
Type
of planting
i. Seed-at-stake planting: Planting seeds in situ
is not found very successful in the country.
ii. Stump planting: Seedlings raised in nurseries
are transplanted after pruning the stem at a height
of 45-60 cm from the collar.
iii. Polybag plants: These plants are raised in two
ways.
(a) Raise stock seedlings in polybags and afterwards
green bud them at the appropriate stage and transplant.
(b) Green budded stumps are planted in polybags of
appropriate size and transplanted.
In both the cases, transplanting can be done when
the plants attain either 2-3 whorls or 6-7 whorls
of leaves.
iv. Budded stump planting: Seedlings raised in nurseries
are budded and transplanted after pruning the stem
at about 8 cm from the bud patch.
Cover
crop
It is strongly recommended to have ground cover crops
particularly of leguminous creepers. The most common
cover crop used is Pueraria phaseoloides and Mucuna
bracteata. Since the seeds of cover crops often have
very hard seed coats, it is advisable to have certain
pre-sowing seed treatment such as acid treatment,
hot water treatment, and abrasion treatment to obtain
a high percentage of germination.
Mulching
This is recommended from early stage of plants using
dry leaves, grass cutting, cover crop lopping etc.
around the plants. Usually November is the ideal time
for mulching to protect the plant from the adverse
effect of drought.
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Manuring
of plants is done in three important stages of growth
namely nursery, young plants and mature trees.
Seedling
nursery
Apply 25 kg of compost and 3.5 kg of rock phosphate
per 100 m2 of the nursery bed as basal dressing.
Application
of 2500 kg of 10:10:4:1.5 N:P2O5: K2O:MgO mixture
per effective hectare (i.e. 25 kg per 100 m2 of the
nursery bed), 6-8 weeks after planting is recommended.
To make 100 kg of the above mixture, use 48.5 kg ammonium
sulphate (20.6% N) or 22 kg urea (46% N), 34.5 kg
rock phosphate (29.0% P2O5), 7 kg muriate of potash
(60% K2O) and 10 kg commercial magnesium sulphate
(16% MgO) or 4 kg magnesite (40% MgO). Use a filler
to adjust the total weight of the mixture to 100 kg.
Bud
wood multiplication nursery
1.
Incorporate 150 kg powdered (100 mesh) rock phosphate
per hectare i.e. 1.5 kg per 100 m2 of the nursery
bed as a basal dressing at the time of preparing the
nursery bed.
2.
Apply of 250 g of 10:10:4:1.5 NPKMg mixture, the composition
of which is given earlier, per plant in two equal
split applications for the first crop of bud wood.
The first application should be made 2-3 months after
planting the budded stumps or cutting back if budding
is carried out in situ. The second application should
be made 8-9 months after planting.
3.
Apply 125 g of 10:10:4:1.5 NPKMg mixture, per plant
in one single application 2-3 months after cutting
back for the second and subsequent crops of bud wood
from the nursery.
Immature
rubber trees
Apply compost / FYM @ 12 kg/pit and rock phosphate
175 g/pit at the time of filling the pit.
From
first to fourth year, 10:10:4:1.5 NPKMg mixture may
be applied @ 225, 450, 450, 550, 550, 450 and 450
g / plant at the 3rd, 9th, 15th 21st, 27th, 33rd and
39th months, respectively.
From
5th year, till tapping begins, where cover crops were
grown and mulching was practiced during the initial
years, 12:12:12 N:P2O5:K2O mixture may be applied
@ 125 kg/ha during April-May and September-October.
To make 100 kg of the above mixture, 26 kg urea, 54
kg rock phosphate and 20 kg muriate of potash are
required. Whereas, in plantation without cover crops
and where mulching was not practiced during the initial
years, 15:10:6 N:P2O5:K2O mixture may be applied @
200 kg/ha during April-May and Sept-October. Mix 33
kg urea, 50 kg rock phosphate, 10 kg muriate of potash
and 7 kg filler to get 100 kg of this mixture.
Mature
rubber under tapping
N:P2O5:K2O (10:10:10) mixture @ 300 kg/ ha or 900
g/tree may be applied every year as a single dose
during April-May or in two splits during April-May
and September-October. To make 100 kg of this mixture,
use 22 kg urea, 50 kg rock phosphate, 17 kg muriate
of potash and 11 kg filler.
Instead
of the above fertilizer mixture, any of the complex
fertilizers of the grades 15:15:15 or 17:17:17 or
19:19:19 N:P2O5: K2O may also be used. The quantities
of these being 200 kg, 175 kg and 160 kg/ha, respectively.
Ammophos (20:20) @ 150 kg mixed with 50 kg of muriate
of potash can also be used for one hectare. For mature
rubber, it will be desirable to follow discriminatory
fertilizer recommendation based on soil and leaf analysis.
This facility is available at the Rubber Research
Institute of India, Kottayam and also at the Regional
Laboratories at Adoor, Kanjirapally, Pala, Muvattupuzha,
Thrissur, Kozhikode and Nedumangadu .
Note: Plantations where rubber trees exhibit magnesium
deficiency symptoms (interveinal yellowing of leaves
during September-October) addition of 50 kg of commercial
magnesium sulphate per ha besides the above NPK mixture
is recommended.
The
weeds commonly found in the rubber plantations are Chromolaena
odorata (eupatorium), Pennisetum sp., Lantana aculeata,
Mimosa pudica and Imperata cylindrica. Growing ground
cover crop is the most efficient practice for weed control
in rubber in early stages. In rubber plantations, the
weeds can be controlled either by manual or chemical means.
The
following weedicides are used in rubber plantations:
Pre-emergent:
Diuron, Simazine, Cotoran, Lasso
Post-emergent: Paraquat, 2,4-D, Glyphosate
Most
of the weedicides have adverse effect on growth of cover
crops. Hence it may be used only on the platforms (planting
lines).
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Abnormal
leaf fall (Phytophthora meadii)
Symptoms
During southwest monsoon period, the fruits rot. Later,
infected leaves fall in large number prematurely either
green or after turning coppery red with a drop of latex
often coagulated in the centre of a black lesion on
the petiole.
Control
Prophylactic spraying of the foliage prior to the onset
of southwest monsoon with 1% Bordeaux mixture (3000-4000
l/ha) or oil based copper oxychloride (30-40 litres
of CDC-oil mixture / ha mixed in 1:5 proportion) is
recommended.
Powdery
mildew (Oidium heveae)
Symptoms
Prominently noticed on newly formed tender flush during
the defoliation period of January-March. Tender leaves
with ashy coating curl, crinkle, edges roll inwards
and fall off leaving the petioles attached to the twigs
giving a broom stick appearance. In later stages on
older leaves white patches appear. Infected flowers
and fruits shed.
Control
For young plants, spray wettable sulphur (0.2%) or carbendazim
(0.05%) at fortnightly intervals. For mature trees,
dust with sulphur 3-5 rounds at weekly to fortnightly
intervals. Sulphur mixed with an inert material like
talc (70:30 mixture) is generally used @ 11-13 kg/ha/round.
Corynespora
leaf disease (Corynespora cassiicola)
Symptom
The disease is prevalent in nurseries (Nov-May) and
mature plantations (Jan-May). Large spots with brown
margin and pale centre are formed, which later fall
off forming shot holes. On mature trees, light green
leaves during refoliation are more susceptible. Defoliation
and dieback of twigs are also noticed.
Control
Shading in nursery reduces incidence. Spraying mancozeb
(0.2%) or carbendazim (0.05%) or Bordeaux mixture 1%
is recommended. In mature rubber, micronized spraying
with oil-dispersible copper oxy chloride dispersed in
spray oil (1:5 proportion) at light green stage of leaves
is effective.
Pink
disease (Corticium salmonicolor)
Symptom
Trees in the age group 3-12 years are highly susceptible.
The seat of infection is usually at the fork region.
White or pink coloured cobweb mycelial growths form
on the surface of the bark with streaks of latex oozing
out from the lesion; resulting in rotting, drying up
and cracking up of the affected bark. The distal portions
of affected branches dry and dried leaves remain on
these branches.
Control
In high disease prone areas, the highly susceptible
clones can be treated as a prophylactic measure with
Bordeaux mixture or Bordeaux paste. In the early stages
of infection, apply Bordeaux paste up to 30 cm above
and below the affected region. Tridemorph (2%) incorporated
in 1% ammoniated field latex is also effective. Tridemorph
(1%) or Thiram (0.75%) in pidivyl, china clay and water
mixed in the proportion 1:2:4 by volume is very effective
for control. Thiram (0.75%) mixed in petroleum wound-dressing
compounds like rubberkote, sopkote, etc. is also effective.
Regular
inspection of trees during July to September for detecting
the infection is recommended. In severe cases, prune
off and burn the dried up branches.
Bark
rot (Phytophthora spp.)
Symptoms
During rainy season, when trees are tapped, depressions
are formed in the tapping panel due to localized rotting
and drying bark. Black vertical lines running downward
into the tapping bark and upwards into the renewed bark
are noticed. The bark when renewed becomes highly uneven.
Control
The tapping cut and nearby bark should be washed with
mancozeb (0.375%) or phosphorous acid (0.08%) at weekly
intervals. The rotten bark may be scraped off and applied
with fungicide and then covered with petroleum wound-dressing
compound.
Other diseases are patch canker, dry rot, Colletotrichum
leaf disease, bird's eyespot, shoot rot, brown root
etc.
The pests associated with rubber are scale insect, mealy
bug, termite, cockchafer grub, mite, snail, rat, etc.
Appropriate control measures may be adopted after identifying
the pest.
Hevea
latex found in the latex vessels contains 30-40% rubber
in the form of particles. Latex is obtained from the
bark of the rubber tree by tapping
Tapping
It is generally economic to begin tapping when 70% of
the trees in the selected area attain the standard girth
of 50 cm at a height of 125 cm from the bud union for
budded trees. For seedling trees, 55 cm at height of
50 cm for BO1 panel and at 100 cm for subsequent panels
is the standard.
Time
and interval of tapping
The best month to open new areas for tapping is March.
It is necessary to commence tapping early in the morning
as late tapping reduces the exudation of latex. In general,
budded trees are tapped on half spiral alternate daily
(1/2S d/2) and seedling plants on half spiral third
daily (1/2S d/3). In the case of high yielding clones
like RRII 105, third daily tapping frequency (1/2S d/3)
has to be followed to reduce the incidence of tapping
panel dryness.
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