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Rubber is a material having varied industrial, technological and domestic uses. It has
high export potentials and is rated as one of the most profitable agri-industrial
ventures in the country.' The prospects of the natural rubber industry in the
Philippines can be gauged by the domestic and export market requirements, Despite
the threat of synthetic rubber, the market for natural rubber still remains healthy
and attractive due to an ever increasing demand for rubber products. Added to this ,
is the unique technical properties of natural rubber making @ suitable for varied
purposes and well favored compared to synthetic rubber. Therefore, the natural
rubber industry will continue to be of greater importance.


In general, rubber is grown within the geographical zones lying 10 degrees to 15
degrees on ether side of the equator. Warm humid climate with temperatures
ranging from 20 to 35 degrees centigrade is required and an annual rainfall pattern
that is fairly distributed and without morning rains is best needed by the crop.

Rubber is suitable in a wide range of soil types provided that drainage, soil reaction
and soil depth are not limiting. Slightly rolling lands with deep surface soil are ideal
for rubber growing. Rubber can be planted in steep slopes provided that contour
planting is observed. Well-drained flat or level lands maybe good also for rubber.
Soils planted to rubber in the Philippines is moderately to slightly acidic (pH ranging
from 4.5 to 6.5) on the standard scale.

Clone selection should be given importance in order to have a successful rubber
plantation. Optimum yields cannot be attained even with a favorable environment I
the clone used is not of high yielding variety.

In most plantations, RRIM 600 occupies at least 70% of the area. The remaining
30% is planted to any of the following: PB 330, RRIM 712, RRIM 703 and PB 235.


Raise seedlings in nurseries for almost a year before transplanting to the field. This
technique is more economical and convenient than direct planting.

Prepare germination beds. The length depends on the number of seeds to be sown.
The width should be about one (1) meter for convenience in cultivation. Use fine
river sand as germinating medium for minimum root damage when the seedlings are
pulled out prior to transplanting. Aged sawdust or dried cogon can also be used.

About 2, 000 seeds can be sown per square meter of germination bed. Overcrowding
of seeds can cause distortion of the roots which may cause difficulty during pricking.
The seeds are closely laid on the surface with the top of the seeds on the level with
the surface of the medium. They start to germinate in one week time. Continue
watering until all viable seeds have germinated. Generally, survival rate from seeds
to seedlings ranges from 80% to 90%.

During the months of August to October, rubber seedlings can be easily obtained
from fresh, large, heavy and shiny seeds. For rootstocks, seeds of Tjir 1 are ideal
because of the vigorous seedlings produced. Other clones are recommended for use
except for PB-86 which produces albino seedlings.

Germination in seedbeds shall be done. It takes seven (7) days before transferring
them to the polybag nursery, if green budding is going to be employed or in the
ground seedlings nursery for brown budding. In which, after six (6) months, the
seedlings are to be budded for 35 days and bagged afterwards. After a period of 4-6
months in the polybag nursery, the seedlings can be planted to the field.

Fertilize the seedlings with balanced fertilizer mixtures starting on the first month
after planting of pre-germinated seedlings. Apply 10-15 grams per seedling or one
teaspoon per application of NPK fertilizer mixtures, in two or three split dosages.
Broadcast the fertilizer about 10cm away from the base of the plant.


The maintenance program of the existing production area will basically involve the
following major activities: fertilization, disease and pest control, ring weeding, cogon
wiping and lining. Said maintenance program will give due consideration to:
attainment of the highest possible yields, minimization of the loss/destruction of
trees due to pests and/or diseases, and proper development of tree girth size.

For areas to be developed yet, the following practices shall be followed:


Plow and harrow the field which was previously planted with annual crops. If
cultivation is needed, a tractor or an animal-drawn plow can be used. Plowing twice
in cross direction during summer to expose and dry the rhizomes of weeds.


The avenue/hedge system is most suitable for hilly areas (10 m x 2 m). The
rectangular or square method (4 m x 5 m) is recommended for flat or slightly
undulating areas. For cash cropping and intercropping purpose, 2 m x 10 m or 2 m x
3 m x 21 m are recommended.


For hilly lands, the practice of contour lining/terracing is recommended. To minimize
soil erosion, cutting of planting terraces is necessary. Cut the soil 20 centimeters in
front of the line of the planting row back into the hillside to give a width of 40 to 150
centimeters with a backward inclination from the horizontal of 2.5 centimeters per 30

A few weeks before transplanting, prepare the holes to condition the soil for quick
growth of young shoots. The size of the hole depends on the nature of the soil and
the planting materials to be used. In most cases, around 60 centimeters is being
practice. Back filling is done at about 5 centimeters above the ground level.


Budded planting materials with at least two fully developed leaf whorls are
recommended for field planting. In planting, remove carefully the bottom of the
polybag using a sharp knife before placing the planting material in the hole. Make a
vertical cut on the polybag starting from the bottom up to its upper surface. Fill the
hole with loose soil until 3/4 full before pulling out totally the polybag. Tamper the
soil around lightly with a wooden pole until about 2 inches of the ground surface is
fully covered.


The three most common cover crops are Pueraria, Calopogonium and Centrosema.
These are established either before or after field planting of rubber.

During the unproductive period, small growers can grow cashcrops. These can be
planted between the rows of rubber to generate supplementary income such as
cereals, legumes, vegetables and selected perennial crops.


Replace vacant or dead hills with planting materials of similar age with that of the
original stand for uniformity.


This should be done during the third year to eliminate the less vigorous trees. This is
the time when the branches and shoots start to close in.


To produce high quality rubber, supply the crop with a balanced amount of essential
nutrients, Nitrogen (N), Phosphorous (P205), Potassium (K20) and Magnesium (Mg).
Nitrogen is commonly needed during seedling stage. This nutrient is essential for cell
production for an increased growth and development of vegetative parts.
Phosphorous is essential for cell division and development of growing tissues.
Potassium (K) nutrients are needed especially by mature rubber trees. Bark
regeneration is encouraged for a positive response to latex yield. For latex flow
stability, Magnesium (Mg) nutrients are required.

For young rubber trees, (3 to 12 months after transplanting), the use of 65 grams of
complete (14-14-14) fertilizer per tree is recommended. During the second year, 125
grams of 14-14-14 applied every six months is sufficient. From third year onward,
higher rates can be applied yearly depending on the needs of the tree.
Fertilizer is applied on the soil layer within the 7.5 centimeters depth range. Distance
from the base may range from 15 to 40 centimeters depending on the age and size
of the tree.

Average fertilizer recommendation per tree are as follows: Nitrogen - 40 grams;
Phosphorous 40 grams; and Potassium-30 to 135 grams.


Start prunning the side branches that developed within the height of 2.75 meters
above the point of scion stock union three weeks after planting until before tapping.


Control of termites, root-feeding grubs and bark borers can be done through the use
of recommended insecticides by pouring the diluted solution in the infested area.
Sucking insects such as mealy bugs and aphids on the other hand, are controlled by
spraying with soap emulsion especially if the infestation is heavy and spreading.

Rats and wild pigs destroying germinating seedlings and young plants can be
controlled by baiting, trapping, hunting or by setting a barbed wire fence with wire
netting about one meter high.


Diseases, particularly those caused by fungi, may infect rubber from
seedling stage to maturity. Rubber diseases and their control are as follows:

1. Bird's Eye Spot (Helminthosporium hevea) Control: weekly spraying of Dithane M-
45 (10% solution of 6 tbsp/4 gal knapsack sprayer) on fully expanded leaves.

2. Collectotrichum Leaf Disease and Anthracnose (Collectotrichum gloeosporoides)
Control: spraying the expanding leaves with Vitigran Blue, Daconil, or Cupravit at the
rate of O.2% or 2. a.i. per lt. of water (IO-Il Tbsp/4gal.) at least 4 rounds at weekly

3. Pink Disease (Corticium salmonicolor) Control: Bordeaux mixture (Lime, 0.36 kg;
copper sulfate, 0.18 kg. or 0.4 lb., water, 15 lt. or 4 gal.) is sprayed on the infected
parts but not advisable for trees in tapping.

4. White root Disease (Rigidoporus lignosos) Control: Regular inspection of tree.
Those with foliar symptoms should be dried up and burned. Adjacent trees should be
treated by carefully removing the earth from around the collar and the first 15 cm of
the lateral roots. Cut and burn any infected wood. Application of Fomac 2 is also

5. Stem Bleeding - There is no known control measure.

6. Black Stripe (Phytophthora palmivora) Control: Regular application of Aliette,
provided the disease is detected early enough. For newly established diseases, a
mixture of 10 gms per lt. of water at 20 ml per tree is applied every four days of
tapping. For serious infection, a mixture of 20 gms per liter of water is used.

Apply fungicide by brushing with a 5-cm paint, brush to cover the entire infected
area above the tapping cut and a strip just below the cut. Generally, a band 5-10 cm
above and 2.5-5 cm below the cut is satisfactory.

7. Moldy Rot (Caratcystis fimbriata) Control: Moldy rot is spread by tapping knives or
tappers' clothing. As a preventive measure, disinfect tapping knives after each
tapping in the infected area by immersion in a fungicidal solution. The most effective
chemical to control moldy rot is Benlate (Benomyl) at O.5% (5-6 tbsp. per 4 gal)
applied four times at weekly intervals.

8. Brown Bast = Flow of latex in diseased bark finally stops due to coagulation of
latex within the vessels. This cannot be controlled when coagulation has set in.
Occurrence of brown bast can be prevented through proper tapping techniques and


In tapping, a thin shaving of bark is removed from the lower surface of the grove to
open the latex vessels in the bark. The barks are blocked by plugs of coagulated
latex The latex vessels are concentrated in the soft bark and the innermost layer of
the hard bark, In tapping , therefore, the bark should be removed as close as
possible to the cambium to serve the greatest number of latex-bearing vessels.
However, the cambium should not be damaged so as not to hinder future tapping
operations. The following tools are needed in tapping rubber trees: tapping knife,
collection cup, vine cup holder and metal spout, a container for coagulant or anti-
coagulant, and a basket for scraps.

Normal tapping system for rubber has an intensity of 100%. This is the s/2.d/2
tapping system. Intensive tapping has a tapping intensity of more than 100%. Since
tapping intensity depends on the length of the tapping cut and the frequency of
tapping, intensive tapping involves either an increase in the length of the tapping cut
or tapping frequency or both. This system can be applied in old trees which are to be
replanted within 10 years.

The system of double-half circumference cut to form a V-cut tapped once in two days
is applicable on trees which are to be felled within two to three years. For areas to be
replanted within a year, the multiple cut system or slaughter tapping method is

The recommended standards for opening a rubber plantation for tapping

I. At least 7O% of the trees has reached the standard girth.

2. For hall circumference alternate tapping (s/2.d/2; half spiral, tapped every second
day), trees should have attained a girth of at least 50 cm at 150 centimeters from
the union. The girth is measured at the height of the lower end of the opening cut on
the first panel.
A cut from "high left" to "low right" cuts a greater number of latex vessels per unit
length of tapping cut than if the cut is made from "high right " to "low left ". For
budded trees with thin bark, tapping is cut at an angle of 30 degrees to the
horizontal. Normally, tapping is done over a period of two to three days. The
oxidation of latex in the tree is governed by transpiration, hence tapping should be
done early in the morning when transpiration is low to obtain high yield.


Contamination of rubber latex must be avoided in order to maintain absolute
cleanliness during tapping and collection of latex. Latex should be collected three
hours after tapping the last tree in a block and placed in a clean plastic pail because
the longer it stays in the cup, the higher the number of microorganisms that are
introduced from the dirt and bark particles present in the tapping cut, spout. and
collection cup. Containers made of plastic or non-corrosive metals should be used for
this purpose. They should be cleaned and thoroughly washed after each use. If
empty oil or kerosene cans are used, they should be painted with Epicote to prevent
rusting. Containers used for latex collection should never be used for other purposes.


Ethrel is the stimulant which is usually used in rubber due to its availability and
satisfactory effect on rubber trees. Application can be done every two (2) months
with a rest period of two (2) months coinciding with the wintering of trees. The
stimulant is applied at a width of about 2.5 cm immediately below the tapping cut.
This is usually done by slightly scrapping a strip of bark wider enough to be
consumed in two months, e.g. 4 cm (I 1/2 inches) on alternate daily tapping.

The use of ethrel may necessitate reduction in tapping frequency, e.g. s/2, d/3, 67%
half spiral every third day and s/2, d/4, 50% half spiral every fourth day. Application
of complete fertilizer of high potash content is recommended at least once a year
since ethrel stimulation results in excessive drainage of essential nutrients due to
increased latex yield. Application rate must be based on yearly soil/leaf analyses.

Technology-advanced plantations advocate start of the ethrel application
commencing from the eleventh year of tapping to avoid a faster decline in yields.


Pre-Coagulation and Anti-Coagulants

Normal pre-coagulation occurs if collection and transportation are delayed. Abnormal
pre-coagulation occurs during rainy days, wintering period and in newly opened
young trees and high cut tapping. Normal pre-coagulation can be avoided or
minimized by the addition of anti-coagu-lants such as ammonia and sodium sulfite
Pre-coagulation is manifested by lumps in latex cups. Clots in the latex, coagulation
during transport and fermentation bubbles in the co-agulum.

Dilution, Standardization and Bulking

The separation of fine sand particles and dirt from field latex by straining alone is not
practical due to the high viscosity of the latex. To facilitate separation of fine sand
and dirt, the fluidity of latex must be increased. This is done by diluting it with water.
Allowing the diluted latex to stand in property constructed tanks causes' sand and
other fine particles to settle.

Since the quality of field latex varies considerably from field to field, the latex in a
plantation must be brought daily to a certain standard by diluting the latex to reduce
the dry rubber content (DRC). Generally, a 1: I ratio of water to field latex is used.
The bulking tanks which are usually cylindrical with a conical bottom should have a
drain tap below the level of the outlet to the coagulating tanks. Diluted latex settles
in IO to 30 minutes. The latex flows from the opened outlet cock into a container if
coagulation is done in pans or into a gutter which leads to the coagulating tanks. In
plantations where there are no facilities for bulking and settling, it is essential to run
diluted latex through a sieve to remove the line dirt particles and pre-coagulated
lumps. Unless there is pre-coagulation, there is usually no need to sieve if bulking
and settling are done properly.


To bring the latex into a state suitable for coagulation, dilution is essential.
Coagulation of the latex is carried out in aluminum coagulating tanks or wooden
tanks lined with aluminum. Coagulating tanks are convenient for large plantations.
The most commonly used tanks are 3 meters long, about 90 centimeters wide and
35 to 45 centimeters deep. it is important to provide slope on the bottom of the tank
(l cm per 60 cm length) towards the drain to facilitate the flow of serum and wash
water. Normally, the tanks are designed to contain 75-90 partitions. Both separate
sheeting tanks which can produce separate 75 to 90 globe of coagulum and
continuous tanks which can produce long continuous sheets are used.

For small plantations, rectangular aluminum pans having a capacity of 4.5 liters or
halved kerosene cans may be used. Min-coagulating tanks capable of holding 36
liters of diluted latex to produce 8 sheets can also be used.

Although many substances can be used for coagulation of latex, only acetic and
formic acids can be used as they are the only recognized standard coagulants. In
practice, the acid required is computed and the solution is prepared by diluting it
with water at the rate of 10 milliliter acid to one Liter.

While the acid is added, the latex should be stirred with aluminum or wooden
paddles. Stirring should be done carefully to avoid internal bubbles and reduce
internal surface foam to a minimum. A considerable amount of foam is produced with
the mixing of diluted acid and latex. This should be removed with a. smooth wooden
board or aluminum skinner to avoid the surface pitting of the sheet when the
coagulum is rolled. The tanks or pans are then left as such without disturbing for
complete coagulation.

When coagulation is complete, the tanks or pans should be flooded with water and
left until machining starts. Since coagulum having all desirable qualities is very soft,
it is easily deformed by careless handling. Excessive handling of the coagulum should
be avoided as much as possible. In case of coagulation in tanks, a chute conveys the
coagulum from the tanks to the sheeting battery. The coagulum can be floated
directly from tanks. In other cases, it is to be lifted and placed in the chute, when
pans are used for coagulation, the coagulum should be detached at the edges and
carefully lifted from both sides of the pan.


Hand or power-operated machines can be used for milling coagulum into sheets. One
end of the coagulum is hand kneaded and passed through the first machine three or
four times, the spaces between the rolls slightly decreasing each time. After this, the
sheet is finally passed through the machine with grooved rolls whose nip is adjusted
to give sheets of 2.5 mm thickness.

To handle large sheets, it is desirable to use a battery of rollers with set spacing. The
sheets should successively pass from one machine to another. During machining, the
water must be sprayed liberally over the sheets to remove the serum, excess acid
and other soluble impurities. Sheeting machines are usually provided with water
spray. In case this is not provided, the sheets are placed in a washing tank, and
washed well in running water. The sheets are cut into a uniform length on a cutting

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