Cocoa
Theobroma cacao
Family: Sterculaceae
History
The
cocoa tree is thought to have originated in the Amazon basin and
spreading to Central America particularly to Mexico. It was known and
used by the natives in the region, such as Olmec and Mayas, and they
considered it as the “food of gods”. Cocoa seeds were used as currency
by the Aztecs who also enjoyed a type of bitter chocolate drink.
Christopher Columbus discovered cocoa beans in America but only after 20
years later, Hernando Cortes discovered the bitter drink used by the
Aztecs and sent the beans and recipes back to King Charles V of Spain.
The Spanish refined the recipes adding sugar and heating the ingredients
to improve the taste. By 1828 the cocoa press was developed, allowing
the extraction of cocoa butter. Later around 1879 The Swiss developed
both milk chocolate and solid chocolate. By 1800’s European Colonial
rulers introduced cocoa to their colonies and after that it was
developed in Africa and Asia as commercial plantations.
Products and Uses
Seeds
are the source of commercial cocoa and the main final product is the
chocolate. Intermediate cocoa products are cocoa butter, cocoa liquor,
cocoa powder and cocoa cake. Cocoa Powder is used in Chocolates, Sweets,
Ice creams Bakery items and Beverages. Besides the traditional uses in
chocolates and confectionaries, cocoa butter is also used in
manufacture of tobacco, soap and cosmetics in some countries.
Major Growing Areas
Suitable
conditions for growing cocoa are found in the Central, North Western,
Sabaragamuwa, Uva, Western and Southern provinces of Sri Lanka. Cocoa
can be considered as the most important tree crop for under planting
coconut and rubber provided suitable soils exist. Total extent of cocoa
is 2472ha and Kandy, Kaluthara , Badulla Kurunegala, Kegalle and
Monaragala districts are the main cocoa growing districts.
Varieties
There
are three main varieties as Criyollo, Forastero and Trinitario. Sri
Lanka had the fame of having “criollo” variety which produce fine and
flavor cocoa but currently most of the cocoa found in Sri Lanka are
crosses of above three main varieties.
Soils and Climatic needs
Soil
The best soils for cocoa are deep, well drained clay loams rich in organic matter. Scattered stones are pebbles are tolerable up to 40% of the surface of such soils. Coarse gravelly soils, sandy soils, shallow soils and soils underlain by slab rock or hard late rite are unsuitable.
Climate
Altitude : up to 600MSL
Temperature : Most suitable temperature is between 21 0 – 32 0 C
Rain fall: 1150 -2500mm is recommended.
P.H.: 5-6.5 is recommended
Atmospheric humidity: thrives best under moist humid conditions
Frequent winds are harmful as it decreases humidity
Shade: Relatively dense overhead shade (40-50%) is essential at the time of harvesting and during first 03 years of growth. Thereafter the shade can de removed with the spread of canopy and 25-30% shade is adequate for grown up cultivations. Where no shade from old rubber, coconut or forest trees is available quick growing trees such as banana, papaya or glyricidia should be established for temporary shade and dadap for permanent shade.
The best soils for cocoa are deep, well drained clay loams rich in organic matter. Scattered stones are pebbles are tolerable up to 40% of the surface of such soils. Coarse gravelly soils, sandy soils, shallow soils and soils underlain by slab rock or hard late rite are unsuitable.
Climate
Altitude : up to 600MSL
Temperature : Most suitable temperature is between 21 0 – 32 0 C
Rain fall: 1150 -2500mm is recommended.
P.H.: 5-6.5 is recommended
Atmospheric humidity: thrives best under moist humid conditions
Frequent winds are harmful as it decreases humidity
Shade: Relatively dense overhead shade (40-50%) is essential at the time of harvesting and during first 03 years of growth. Thereafter the shade can de removed with the spread of canopy and 25-30% shade is adequate for grown up cultivations. Where no shade from old rubber, coconut or forest trees is available quick growing trees such as banana, papaya or glyricidia should be established for temporary shade and dadap for permanent shade.
Crop establishment
Planting material
Seeds are normally used for planting. Pods, taken from selected cocoa lines, are opened to get fresh seeds and then seeds are thoroughly washed to remove the mucilage. Seeds can be sown in a sand bed or can be directly planted in a poly bag filled with equal mixture of top soil, cow dung and san. If sown in a sand bed, seedlings should be replanted in a poly bag.
Bud grafted cocoa plants are also used as planting material especially in multiplying high yielding varieties.
Spacing:
For monoculture 10’x10’ (1100 plants/ha)
Intercropping with rubber – 12’x20’
Intercropping with coconut – 26’x26’
Field Planting
Planting is done with the on set of monsoon rains. After the land preparation seedlings are planted in pits of 11/2’x11/2’ in size and filled with top soil and cow dung. Temporary shade should be provided if there is no adequate shade in the field.
Crop management
Weeding
When the cocoa plants are young regular weeding (4-5 times a year) is necessary. When cocoa trees are grown weeding in once or twice a year is sufficient.
Fertilizer application
Recommended mixture - 770 kg / ha at the density of 1100 plants/ha
Seeds are normally used for planting. Pods, taken from selected cocoa lines, are opened to get fresh seeds and then seeds are thoroughly washed to remove the mucilage. Seeds can be sown in a sand bed or can be directly planted in a poly bag filled with equal mixture of top soil, cow dung and san. If sown in a sand bed, seedlings should be replanted in a poly bag.
Bud grafted cocoa plants are also used as planting material especially in multiplying high yielding varieties.
Spacing:
For monoculture 10’x10’ (1100 plants/ha)
Intercropping with rubber – 12’x20’
Intercropping with coconut – 26’x26’
Field Planting
Planting is done with the on set of monsoon rains. After the land preparation seedlings are planted in pits of 11/2’x11/2’ in size and filled with top soil and cow dung. Temporary shade should be provided if there is no adequate shade in the field.
Crop management
Weeding
When the cocoa plants are young regular weeding (4-5 times a year) is necessary. When cocoa trees are grown weeding in once or twice a year is sufficient.
Fertilizer application
Recommended mixture - 770 kg / ha at the density of 1100 plants/ha
| Components of the mixture |
Parts by weight |
Nutrient in the mixture |
| Urea (46%N) | 4 | 14%N |
| Rock phosphate ( 28 % P2O5) | 5 | 11% P2O5 |
| Muriate of potash (60% K2O) | 3.5 | 14% K2O |
| Kieserite (24%MgO) | 1 | 2%MgO |
| Age of plantation |
Maha Season (mixture Kg/ha.) |
Yala Season (mixture Kg./Ha.) |
| 1st Year (kg) | 137.5 | 137.5 |
| 2nd Year (kg) | 275 | 275 |
| 3rd Year and onwards (kg) | 385 | 385 |
Pruning
Removal of water shoots is essential for successful in cocoa All water shoots, which develop from the main stem, should be removed when they are small as they depress the yield if allowed to mature. All dead branches and dry twigs should also be removed.
If shade is high shade trees should be pruned and light shade should be maintained.
Crop Protection
DiseasesPod rot disease
Initial symptoms are small brown lesions with water soaked appearance. If the humidity remains high brown lesions spread very fast. As the disease develops a light bloom of sporangia is produced about 1cm behind the advancing margin of the lesion. To control remove all infected pods and destroy them, spray 1% Bordeaux mixture or any other copper fungicide. Excess shade and water shoots as well as unwanted branches should be removed.
Swollen Shoot Disease
A characteristic symptom of the disease is the swelling of branches and production of leaves with mosaic symptoms. It is caused by a virus and transmitted by mealy bugs. However in Sri Lanka disease is caused by a mild strain hence the economic loss is negligible. Disease can be controlled by removing infected plants and, controlling mealy bugs and avoiding the use of planting material from infected plants.
Pests
Cocoa capsid bug and Cocoa Mealy bugs are the important pests in cocoa cultivation. Nymphs and adults of cocoa capsid bug feed on coca pods, tender leaves and stems. They suck juice from plant tissues resulting in small water soaked areas on the pods. Lesions are circular and rapidly turn back. Damage can be controlled by removing the excess shade and if serious, by applying chemicals.
Harvesting and Post Harvest practices
Harvesting
Trees start bearing in the 4th year. Fruits take about 5 months to develop into maturity. Only fully ripened fruits, which are in yellow to orange in color, are harvested using a sharp knife. Open the pods as soon as possible after picking, preferably using a wooden mallet and seeds should be collected into gunny bags.
Processing
Cocoa beans have little commercial value if they are not properly fermented and cured. The principle behind the fermentation is to kill the embryo and only after that process the flavor and aroma is developed. The notable physical change at the end of the fermentation is the change of deep purple color in to chocolate brown in the forestaro type and yellow to cinnamon brown in the criollo type. There are several methods of fermentation which can produce well fermented cocoa. Those are sweat box fermentation, heap fermentation, tray fermentation and box fermentation. The selected method will depend on the scale of production, cost and the availability of labor. The time of fermentation is varying from 2-6 days which depend on the variety of cocoa. Fermented cocoa beans are sun dried using artificial dryers.
Standard quality specifications
The international cocoa standards require cocoa of merchantable quality to be fermented, thoroughly, dry, free from smoky beans, free from abnormal or foreign odors and free from any evidence of adulteration.
Trees start bearing in the 4th year. Fruits take about 5 months to develop into maturity. Only fully ripened fruits, which are in yellow to orange in color, are harvested using a sharp knife. Open the pods as soon as possible after picking, preferably using a wooden mallet and seeds should be collected into gunny bags.
Processing
Cocoa beans have little commercial value if they are not properly fermented and cured. The principle behind the fermentation is to kill the embryo and only after that process the flavor and aroma is developed. The notable physical change at the end of the fermentation is the change of deep purple color in to chocolate brown in the forestaro type and yellow to cinnamon brown in the criollo type. There are several methods of fermentation which can produce well fermented cocoa. Those are sweat box fermentation, heap fermentation, tray fermentation and box fermentation. The selected method will depend on the scale of production, cost and the availability of labor. The time of fermentation is varying from 2-6 days which depend on the variety of cocoa. Fermented cocoa beans are sun dried using artificial dryers.
Standard quality specifications
The international cocoa standards require cocoa of merchantable quality to be fermented, thoroughly, dry, free from smoky beans, free from abnormal or foreign odors and free from any evidence of adulteration.
Grade I Grade II Gabling
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