Cocoa crop diseases

Cocoa pods are affected by frosty pot rot caused by Moniliophthora roreri and black pod disease caused by Phytophthora palmivora.

Black pot rod disease affects the cocoa pods seriously in all countries inducing average losses above 30%.

The attack by disease may result in a direct loss of crops as with Phytophthora pod rod and other pod diseases, or the tree may be debilitated , as with vascular –streak dieback.

In West Africa the best known virus disease of cocoa crops is swollen shoot.

The first recognizable symptoms of the disease are swellings on the branches and twigs and leaves become asymmetrical. Later chlorosis takes the form of blotching or spotting.

Water plays an important role in the spreading of the fungus from one pod to another and in the actual infection of the pod itself. The best known fungal disease also effects cocoa. This is black pod whose severity has been known to be closely related to the intensity of rainfall, particularly in the months of July and August.

To counter diseases it is first necessary to identify the cause, then to assess the damage likely to be caused; possible control measures should be examined.

Some diseases such as the virulent forms of virus are very difficult to control, and the diseased trees have to be cut down but even then it is difficult to eradicate the disease.
Cocoa crop diseases 

Cocoa tree

Cocoa, Theobroma cacao L., is a perennial crop, originally from the South and Central America and normally cultivated in the tropics from latitude 18 ° N to 15 ° S, mainly in small farms, under the shade of native trees.

The plant is grown for its fruits known as cocoa pods. When ripe, these pods are cut down and opened and the beans are removed. The pods contain seeds, which are fermented with mucilage surrounding them and then dried to give fermented dried cocoa, the raw material used in food industry.

Cocoa is now widely grown in the tropics, usually at altitudes less than 300 m above sea-level, where it needs a fairly high rainfall and good soil.

Rainfall must be plentiful and well distributed, with average monthly rainfalls in excess of 1500 mm.

Cocoa tress can take up to four years from planting before producing enough fruit to merit harvesting. They may live for 80 years or more, although the fully-productive period is usually about 20 years.

Cocoa trees do not reach full production capacity until they are roughly 10 years of age.

The cocoa beans are the major ingredients for the cocoa industry, for the manufacturing the chocolate and derivatives, cosmetics and medicines.

Cocoa processing takes place mainly in importing countries. The processes include shelling, roasting and grinding the beans. Almost half of each bean after shelling consists of a fat called cocoa butter.

In the manufacture of cocoa powder for use as a beverage this fat is largely removed.
Cocoa tree

Purple cocoa beans

Purple beans refer to low quality beans with purple color. The main reason for purple bean is a lack of adequate fermentation.

When harvested, cocoa beans are recovered from the pod and enveloped by a pulp that needs to be removed.

Then cocoa is fermented and over the course of five days, the fermentation process induces biochemical changes in the beans. The rich aroma develop, and the beans change from purple to chocolate brown. If the cocoa is under-fermented then the beans retain bitter flavors and appear slaty or purple in color.

Purple bean produce bitter and astringent flavors. However they are not usually classified as defective because there is a wide range in degrees of purple color and it is appreciate to define the various category precisely.

Unfermented cocoa has a lower value compared with fermented beans. The precursor to the chocolate flavor are not formed and such cocoa has limited uses.

The industry standard for well fermented cocoa beans is 85%, measured by sampling 20 bean from sack and finding that more than 17 are not purple.

Purple cocoa beans