Cocoa Cultivation

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 the 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 underplanting coconut and rubber provided suitable soils exist. The 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 of Criollo, Forastero, and Trinitario. Sri Lanka had the fame of having “Criollo” variety which produces 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 are underlain by slab rock or hard laterite are unsuitable.

Climate

Altitude: up to 600MSL

Temperature: Most suitable temperature is between 210 – 320 C


Rainfall: 1150 -2500mm is recommended.


pH: 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 be 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 gliricidia 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 an equal mixture of topsoil, cow dung, and sand. 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 onset of monsoon rains. After the land preparation seedlings are planted in pits of 1 1/2’ x1 1/2’ in size and filled with topsoil 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 once or twice a year is sufficient.

Fertilizer application

Recommended mixture - 770 kg / ha at the density of 1100 plants/ha

Pruning

Removal of water shoots is essential for success 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 the shade is high, shade trees should be pruned and light shade should be maintained.

Crop Protection

Diseases

Pod 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. The 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 cocoa 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 are developed. The notable physical change at the end of the fermentation is the change of deep purple color into chocolate brown in the Forastero 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 for 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.

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