Trends in consumption and prospects Indonesia apart, there is no evidence of any great growth in the clove market over the past 50 years. In spite of the partial recovery in 1954-8 in comparison with the 1950-3 figures, which must have been influenced at least to some extent by the after-effects of the Second World War, trade sources confirm that clove consumption is not increasing significantly in the long term.

Not much is known about the structure of Madagascar’s export trade, but it seems to have been more centralized than was the case in pre-revolution Zanzibar, and in any case the price of cloves from Madagascar had always tended to follow that of Zanzibar cloves, a situation which continued to apply after 1964.

These figures apply to present-day usage and in the past the proportion attributable to culinary usage was much higher; oleoresin extraction is a comparatively new departure and it is only during the past 25 years that the mass markets for cosmetics and for many various prepared foods have really come into their own.

Cloves thrive best in insular maritime climates at low altitudes in the tropics. They are seldom grown above 200-300 in above sea level, but Yegna Narayan Aiyer (1960) records them at over 900 m in India, and Sheffield (1950) at 600 in in the Seychelles. In their original home in Banda in the Moluccas, which is practically on the Equator and where the trees are semi-wild, the rainfall varies from 2 210-3 607 mm per annum, with no pronounced dry period, and temperatures ranging from 24 to 30 C in the south-east monsoon and from 27 to 33 C in the north-west monsoon. Some drier weather is desirable for harvesting and drying of the crop. The continuously humid climate of Singapore was not as successful for cloves as was Penang.

Upright hardwood poles, for which clove saplings are sometimes used, are placed 2.5 in apart along the side of each path. On these are placed horizontal cross-members; in Zanzibar these are commonly mangrove poles which are weather-resistant. These support the screens, which can be rolled back in wet cloudy weather or when hardening off the seedlings prior to lifting.

If we accept the separation, the correct scientific name for the clove is Syzygium aromaticum (L.) Merr. & Perry. The most common synonyms are Catyophyllus arotnatica L., Eugenia aromatica Kuntze, E. caryophyllata Thunb., and E. caryophyllus (Sprengel) Bullock & Harrison.

A Zanzibar Arab, Harameli bin Saleh, said to have been banished by the Sultan for the crime of murder, is thought to have been the servant of a French officer and to have obtained the seeds in Reunion. These he presented to the Sultan, Sayyid Said bin Sultan, and so obtained his pardon. The first plants were grown near the royal palace of Mtoni, 6 km north of the town of Zanzibar, with later and more extensive plantings at Kizimbani.

On the founding of Penang by Captain Light in 1786, clove trees seem to have been sent from the Seychelles, but they did not survive. The East India Company’s botanist, Christopher Smith, who was trained at Kew, was sent to the Moluccas, of which the British had obtained possession, to obtain plants of cloves and nutmegs.

Unthrifty exposed trees are often attacked by white fly, Aleurodicus pimentae Laing. The eggs are laid on the surfaces of the leaves and hatch in 6-9 days. The larval stage, which secretes’ honeydew, lasts 22-26 days and the pupal stage 12-25 days.The pest is attacked by the fungus Aschersonia aleurodis, particularly in shady places in damp weather, and artificial inoculation is possible. Red-banded thrips, Selenothrips rubrocinctus (Giard) sometimes infest pimento trees, the damage appearing as silvery-white scale on the undersurface of the leaves, mostly along the midribs. Badly infested trees may fall. It can be controlled by malathion or demethoate.

Bagworm caterpillars of the species Oeceticus abbottii will feed on the leaves of pimento, sometimes denuding small plants. It can be controlled by a stomach poison.

The symptoms of die-back, which rarely attacks immature trees, resemble that caused by C. fimbriata on other tree crops. The disease usually starts on one limb as a result of branch breaking or other injury and spreads over the tree in a period of years. If the primary infection is below the crotch of the tree, death may occur within a few months. Bark canker and dark streaking of the wood of the infected parts occur, together with drying out of the leaves as the die-back progresses from limb to limb.

Recently, it was established at the Institut de la Recherche Agronomiques de Madagascar (a Government organization), that the dark colour of the oil was due to iron eugenates.

It was recommended that the iron swan necks, condensers and separators should be replaced by similar equipment made of aluminium; it was later reported that private distillers had ‘invested in modern apparatus which produces a very light-coloured oil of perfect quality’. It has been found in many cases in Madagascar that distillation of leaves leads to over-harvesting for present gain at the cost of subsequent clove harvests.

The eugenol content of the oil is dependent upon the time taken to distil the charge. A rapid distillation provides an oil with a high eugenol content, and Belcher (1965) recommends this procedure if the oil is to be used purely as a source of eugenol.

Clove leaf oil is produced in the Malagasy Republic and, to a lesser extent, Indonesia. In Madagascar the oil is distilled in the clovecool spring water for the condensers is freely available.

The harvested clusters are taken to the plantation headquarters where the cloves are removed from the stems consisting of peduncles and pedicels. Portions of stems remaining on the buds will spoil the grade of the sample.

They concluded that it is not advantageous for cloves and suggested that clean-weeding, plus a mulch, was the best form of management. Where there is adequate rainfall, inter-row planting of the three cover crops recommended for Hevea rubber (Purseglove, 1968) offer good possibilities. These are Calopogonium mucunoides Desv., which grows quickly, gives good early cover in the sun and lasts 18 months; Centrosema pubescens Benth., which makes slow early growth, but persists under shade; and Pueraria phaseoloides, which is the most vigorous when well established with little overhead shade. They are planted in the proportion of 2 : 2 : 1. The seed should be treated with concentrated sulphuric acid or mechanically scarified before sowing to speed up germination and inoculated with the correct Rhizobiurn. They can be sown in drills at a seed rate of 5-7 kg/ha, preferably with some phosphatic fertilizer, and kept free from weeds during early growth. They should be prevented from encroaching on the clove trees.

When the spice is intended for distillation of pimento berry oil, the appearance is not of great importance and the principal criterion for quality is a high content of volatile oil which possesses a desirable aroma and flavour. The volatile-oil content and the aroma/flavour properties of the spice are governed by the intrinsic chemical characteristics of the cultivar grown.

Jamaican pimento sets the standard for quality and it possesses the best appearance, aroma and flavour, and volatile-oil content 4-4.5 per cent). The dried berries range in size from about 6.5 to 9.5 mm in diameter and there are approximately 13 berries per gram. The spice from this source is the only type which is used for distillation of pimento berry oil.

The stage of maturity of the berries at harvest is also of great influence on the quality of the final dried product. Harvesting should be undertaken when the berries are fully developed but still green in colour. Ripe berries have a rather lower volatile-oil content and also dry to a black colour, which detracts from their appearance.

The extensive method of growing the crop in Jamaica usually entails very little care and attention to the pimento trees. The larger weeds in the pasture in which it grows may be controlled from time to time by cutlassing. The branches cut from the trees during harvesting may be put round the trees as a rough mulch.

Pucciniapsidii was originally described by Winter in Brazil on Psidium pomiferum L., which is usually regarded as a form of the common guava, P. guajava L., and which is attacked by the disease in Puerto Rico. The guava seems to be immune from both the strains of the disease which occur in Jamaica.

With the provision of seedlings, and later of vegetatively propagated clonal material, improved attention should be paid to the cultivation of the crop. By the use of the correct spacing the trees should he given enough space to develop low branches and some early training of the trees should be possible. Care during the early years of growth is essential if good trees which yield early and abundantly are to be produced. The trees should be circle-weeded and mulching may be an advantage.

The most important disease of clove trees in Zanzibar and Pemba is sudden-death disease. It has been known in Zanzibar for over a century and the periodical waves of incidence have culminated in losses which, since 1930, are said to have accounted for the destruction of about half the mature trees of Zanzibar Island and very numerous small outbreaks in Pemba.

Various die-backs have been described, including the sudden-death fungus, Valsa eugeniae, when entering the branches as a wound parasite. An extremely serious condition, however, is caused by the fungus Cryptosporella eugeniae Nutman & Roberts (syn. Endothia eugeniae (Nutman & Roberts) Reid & Booth). This is always associated with some form of injury to the tree, particularly when branches are broken during harvesting. The branch slowly dies back, the leaves turning brown, and the fungus proceeds downwards.

The dried unripe fruits of Pimenta dioica,,a,smallish, evergreen tree, provides the culinary spice pimento of commerce. It belongs to the Myrtaceae, the same family as the clove. Pimento is also called allspice, as the flavour is said to resemble a mixture of cinnamon, clove and nutmeg. It is sometimes known as Jamaica pepper.

The first record of pimento being exported to London seems to be in 1601, when what appears to be pimento was given to Clusius by Garret, a London druggist. It must have reached Spain at a much earlier date.

An oil is extracted from the leaves which has been in commercial production in Jamaica since 1920. There was a considerable export of pimento saplings towards the end of the nineteenth century for use as walking sticks and umbrella sticks.

Patrick Browne (1775) records that the export of pimento had reached 438000 pounds, valued at 21925 by 1755, that by that time it was cultivated with great care and was planted in regular groves or `walks’. He also gives what appears to be the first record of barren trees.