SCIENTIFIC NAME: Annona cherimola
FAMILY: Annonaceae

Like many tropical fruits, both exotic and familiar including the avocado, abiu, pawpaw, pineapple and perhaps even the coconut, the custard apple is native to Latin America. Its precise source of origin remains unknown, but its representation on pottery found in pre-columbian tombs in Peru and a research expedition of 1951 suggest fairly conclusively that the centre of dispersal of the fruit was the Andes of present day Ecuador and Peru.

From Andean valleys between 1500 and 2200 metres above sea level, it spread throughout much of south and central America. Following the Spanish conquest of the region in the sixteenth century, this sub-tropical species of Annona called chirimoyo* by the Spaniards and known botanically as A. cherimola - was taken to Spain itself, where it was first mentioned in 1757, and thence to other parts of the sub-tropical world.

Other species, the soursop, (A. muricata), the bullock's heart, (A. reticulata) and the sweetsop (A. squamosa) originate from more lowland parts of tropical America and the West Indies, and were adopted elsewhere in low latitudes. Many hybrids have since been bred, of which the atemoya, a natural hybrid of cherimola and squamosa, has become the basis of the north Queensland custard apple industry.

Long neglected in Spain, as elsewhere, the cherimoya has recently emerged as a major commercial fruit along the Costa del Sol between Malaga and Motril on the southern coast of the peninsula. This region has a long history of cultivation that dates back at least to the Moorish period (8th - 15th century A.D.) when sugar cane, fruit trees and vines were important crops. Sugar cane had become the dominant product by the mid-19th century and remained so until falling yields and poor tenancy conditions led to a rapid decline in cultivation of the crop after 1970. By the mid-1980s, the area under cane had declined to about 1275 hectares, surviving mainly on delta and alluvial land around Motril and Salobreña.

West of the remaining area of cane, farmland has been converted to fruit tree cultivation, mainly of avocado and cherimoya, usually grown together on mixed holdings. Cherimoya plantings increased from some 400 hectares (representing about 71,000 trees) in the early 1980s to about 2500 hectares in 1987.

* The origin of the Spanish name, chirimoyo, and its English derivative, cherimoya, is interesting. It has been suggested by Spanish writers that the name comes from the Quechua, the language of a group of Andean people, and means either 'cold seed' (chiri moya) or 'cold bosom' (chiri moyu). The latter interpretation is partly strengthened by the existence of the mammillaris or mamillata variety, a fruit with prominent protuberances and reputedly named 'Teton de Venue' (Venus's breast) by a French horticulturalist (the atemoya, African Pride, is of this botanical variety).

Average annual production per tree is between 60 and 80 kilograms, representing about 10 tonnes per hectare. The trees are concentrated in the vicinities of Almuñecar, Jete, Itrabo and Otivar, and collectively make this coastal district of Granada the leading world producer of fruit. Other world commercial producers include Peru (50 ha), Bolivia (1000 ha), Chile (700 ha), Ecuador (300-400 ha) and California (50 ha). Holdings have commonly been smaller than one hectare, but in recent years larger plantations have been established as new entrepreneurs have entered the industry.

The cherimoya along this coast is found at altitudes varying from a few metres above sea level to over 600 metres, and within 0.2 to 15 kilometres of the seashore. The tree flourishes regardless of exposure, though protection from the strongest prevailing winds off the sea assists greatest development. It grows best on neutral or slightly acid soils (pH7 or less), with organic matter of 1.7 - 2.7% and of sandy clay loam texture.

Deep, loose, light and cool soils with high moisture retention allied with good drainage are ideal, but current plantings are on rather heavy, compact alluvial soils which flood easily and which hinder adequate aeration and drainage. A general lack of potassium in the soils of the Costa del Sol requires its application, along with nitrogen fertilisers. Irrigation is necessary between March, April and September, the long dry Mediterranean summer. The tree is susceptible to attacks from the Mediterranean fruit fly (Ceratitis capitata), the most serious pest which can cause considerable damage, soft brown scale (Coccus hesperidum), which invades shoots and fruits, and citrus mealybug (Pseudococcus citri), which principally attacks the fruit. Root rot occurs especially in those poorly-drained soils subject to the occurrence of standing water in years of high rainfall.

Although over 200 cultivars are held at the local experimental station near Malaga, the main variety grown is the Fine de Jete (Impressa type). This is the most productive variety under Spanish conditions, with the greatest number of fruits setting. It is characterised by slight depressions in the skin like platelets with raised outlines delineating each carpel unit like a series of thumbprints. The average weight of the fruit is about 170g and its skin is yellowish or whitish-green upon ripening. The Fino de Jete is juicy with a semi-acid flavour but has a rather high proportion of seeds, representing about 6.6 per cent of the fruit, and has a high tendency to set small and misshapen fruits. Deficiencies in natural pollination are a major problem with fruit set which can be increased twenty-fold by artificial pollination.

Ripening of the Spanish crop begins early in the autumn and may extend into the new year, though the main season is from about 10th October to 20th November. This relative inflexibility of seasonal supply tends to glut markets in October and November and depress prices. For this reason, the cherimoya is grown alongside the avocado, whose much longer season of production helps maintain stability in farm incomes, and has not become an important export fruit. Fostering of markets outside Spain itself, where 90-95 per cent of the fruit is sold, has proved difficult in the face of the very limited season of supply.

The principal demand at present for the cherimoya in Spain is as a dessert fruit and it is increasingly popular during its short season. Marketing the fresh fruit, which discolours easily, has its problems since it requires a constant temperature of 9° - 12°C, with damage occurring at 8°C, the more common storage temperature for other fruits such as the banana. Processing as yet is poorly developed and might not be profitable to growers, since manufacturers would probably enter the market only at the time of glut. Nevertheless possibilities are seen for the use of the fruit in the preparation of ice-cream, yoghurts, fruit cocktails, jams and manufactured desserts.

The expansion of cherimoya production in Spain depends upon solutions, or at least partial solutions, to a number of problems. These relate to farm practices, especially to better irrigation techniques, and to overcoming the problem of pollination; to the development of varieties which will permit the extension of the harvesting season and which will have fewer seeds (seen as necessary if the fruit is to be popularised in non-olive-eating markets!); and to the development of freezing or manufacturing outlets. The anticipated extension of the European freeway system to Malaga by 1992 is expected to attract larger numbers of tourists from northern Europe to the resorts of the Costa del Sol, some of whom will be potential consumers. The penetration of the wider European market by Spanish cherimoya producers seems likely during the next decade as progress is achieved in improving cultivation and marketing.

Philip Courtenay
James Cook University CAIRNS CAMPUS

DATE: September 1990

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