Changes

*Cocoa, cacao (En). *Cacaoyer (plant), cacao (product) (Fr)

* "fine" or flavour Criollo, Trinitario and the Nacional (Ecuador) cocoa, which account for less than 5% of the total production, and

* "bulk" or ordinary cocoa produced worldwide from Forastero cultivars.

* Criollo: rather weak-growing tree with relatively low yields, very susceptible to diseases and pests; pods longish and pointed, usually deeply furrowed and warty, thin and soft husk without lignification; green or red immature pods, ripening to yellow or red; 20-40 beans per pod; beans large and almost round in cross-section, requiring 2-3 days fermentation only; white to pale purple cotyledons.

* Forastero of lower Amazon basin (LA): mostly the Amelonado populations; large trees coming into bearing late, but high yielding; immature pods light green ripening to yellow, spherical shape with rounded or very bluntly pointed ends, generally smooth surface with shallow ridges, husk thick and hard with some lignification; beans flat and dark purple, about 40 per pod.

* Forastero of upper Amazon basin (UA): highly variable wild populations from the centres of genetic diversity; sources of plant vigour, productivity and resistance to diseases and pests; pod size and shape variable, but often rather small, pointed, sometimes with a narrow neck, often deeply furrowed and warty surface, but sometimes also smooth; husk comparatively thick and hard, often with distinct layer of sclerenchyma; immature pods always green, ripening to yellow; 30-60 beans per pod; beans small and flat; cotyledons dark purple, but occasionally light red or white.

* Trinitario: natural hybrid between Criollo and Amelonado Forastero; very heterogeneous population but generally much more vigorous and hardy than Criollo; pods variable in shape and husk thickness, smooth to warty surface; immature pods whitish, green, red or purple, ripening to yellow, orange or red; beans plump to flat; cotyledons white to dark purple.

Botanically, ''T. cacao'' has been subdivided into subsp. ''cacao'' (with 4 formas) and subsp. ''sphaerocarpum'' (Chevalier) Cuatr. The former covers the Criollo group, the latter the Forastero and Trinitario groups. For cultivated plants, however, a classification into cultivar groups and cultivars would be more appropriate, but no such classification yet exists. The great cultivars of the older cocoa-growing areas, i.e. the Criollo of Central America and the Caribbean, the Forastero-Amelonados of Brazil and West Africa, the "Nacional" of Ecuador and Trinitarios of Cameroon and Papua New Guinea, are gradually being replaced by hybrid populations obtained by crossing accessions of UA Forasteros with local selections. These hybrids accounted for 40% of the world cocoa area in the late 1990s, including 5% clonal plantings. The expansion of cocoa in Malaysia (Sabah) during the 1980s and more recently in Indonesia (Sulawesi and Sumatra)is almost entirely based on such hybrids, propagated as seedling populations or selected clones.

Every year about 40% of the world cocoa crop is lost due to diseases. Black pod caused by ''Phytophthora palmivora'' is of worldwide significance, but the more aggressive ''P. macrokarya'' is restricted to West Africa. ''P. palmivora'' is also the pathogen of bark canker, which is of particular importance in Papua New Guinea. Witches' broom disease ( ''Crinipellis perniciosa'' ) and moniliasis or frosty pod rot ( ''Moniliophthora theobromae'' ) are two fungal diseases that have co-evolved with the crop in Latin America but have not been observed outside that continent. After large areas of cocoa were established in Africa, the trees became infected by the swollen shoot virus, transmitted by mealybugs from several indigenous tree species. Swollen shoot had a devastating effect on the cocoa industry in Ghana. A fungal disease specific to South-East Asia is vascular streak dieback caused by ''Oncobasidium theobromae'' . It causes dieback of branches, especially in young trees. The disease was first reported in Papua New Guinea in 1960 but is now also present in Malaysia, the Philippines and Indonesia, where it is particularly severe in areas of high rainfall. A combination of chemical control with fungicides (e.g. triazoles) and sanitation pruning is recommended, but the existence of high levels of host resistance in certain Forastero accessions offers opportunities for a more effective way of combating this disease. In South-East Asia, especially Trinitario type cocoa is also susceptible to anthracnose ( ''Colletotrichum gloeosporioides'' ).

Mirids are the most important insect pest of cocoa on a world scale. All regions have their specific mirids, causing severe damage to twigs, branches and young pods. In West Africa the most important pests are mirids of the genera ''Distantiella'' and ''Sahlberghella'' . In South-East Asia, mirids of the genus ''Helopeltis'' are a major pest. Biological control with the ant-mealybug complex has been successfully re-introduced to regulate ''Helopeltis'' .

The cocoa pod-borer, the larva of a small moth ( ''Conopomorpha cramerella'' ), is the most serious insect pest of cocoa in South-East Asia. It bores into the cocoa pod and by feeding on the placental tissues it reduces or prevents normal bean development. During most of its life, the insect is protected within the pod and so is difficult to control. At the beginning of the 20th Century, the cocoa pod-borer largely destroyed the early cocoa industries of North Sulawesi and Java. The current decline of cocoa production in Malaysia can be partly attributed to this pod-borer. It is increasingly a problem in Indonesian (Java, Sumatra, Moluccas, Sulawesi) and Philippine (Mindanao) cocoa.

A variety of insect pests are important during crop establishment, because they destroy the apical bud and delay or prevent canopy formation. Larvae of the moth ''Tirocola plagiata'' , the cocoa army-worm, cause extensive damage to young plants, especially in Papua New Guinea. Both rats and squirrels can account for a considerable part of total crop losses in South-East Asia. The only effective control measures are baiting and trapping.

Priorities in national cocoa breeding have shifted to host resistance to the globally important black pod and regionally important diseases, such as witches' broom in Brazil, swollen shoot virus in Ghana and vascular-streak dieback in South-East Asia. Disease resistance has to be a component of a fully integrated breeding programme, as resistance is only meaningful to the cocoa grower in combination with acceptable agronomic characteristics. In the case of vascular-streak dieback, high levels of host resistance have been found in some UA Forastero accessions (e.g. SCA and NA) and progress in breeding resistant hybrid cultivars is good. Host resistance to black pod exists in UA Forastero germplasm (e.g. SCA, PA and P) but levels are usually low, making it necessary to accumulate resistance genes in recombination crosses between progenitors prior to integration in the main breeding programme. Recent development of early preselection tests by artificial inoculation of leaf disks (Trinidad, Ivory Coast) should accelerate selection. An ecologically acceptable solution to the serious menace of the pod borer to the South-East Asian cocoa industry may be found in an integrated approach including biological control (e.g. egg parasitoids of the genus ''Trichogrammatoidea'' ) and breeding for partial resistance or for a preventive mechanism, such as the presence of a sclerotic layer in the husk barring penetration of the borer in the pods of certain UA Forastero accessions.