CROP HUSBANDRY-NUTMEG CULTIVATION PRACTICES IN KERALA

NUTMEG (Myristica fragrans)


Nutmeg requires a hot, humid climate without pronounced dry season. The soil should be rich in organic matter and well drained. The tree prefers partial shade. Sheltered valleys are the best suited. It can be grown up to about 900 m above MSL.

Variety: IISR-Viswashree

Seeds and sowing
Fully ripened tree-burst fruits are selected for raising seedlings. The fleshy rind and the mace are removed before sowing. The seeds should be sown immediately after collection. If there is any delay in sowing, the seeds should be kept in baskets filled with damp soil. The seedbeds of 100-120 cm width, 15 cm height and of convenient length may be prepared in cool and shady places. A mixture of garden soil and sand in the ratio 3:1 may be used for preparing nursery beds. Over this, sand is spread to a thickness of 2-3 cm and the seeds dibbled 2 cm below the surface at a spacing of about 12 cm on either side. Seeds germinate within 50-80 days after sowing. When the plumule produces two elongated opposite leaves, the seedlings are to be transferred from beds to polybags.

Planting
Since the nutmeg trees require shade, suitable fast growing shade trees like Albizia, Erythrina etc. are planted in advance. Banana can also be grown as a shade crop in the early stages. Pits of 90 x 90 x 90 cm are dug at a spacing of 8 x 8 m with the onset of southwest monsoon. The pits are filled with topsoil and compost or well-decomposed cattle manure and seedlings are planted.

Manuring
Apply 10 kg cattle manure or compost per seedling during the first year. Increase the quantity gradually till a well-grown tree of 15 years and above receives 50 kg of organic manures per year. Apply N:P2O5:K2O @ 20:18:50 g/plant during the first year. This may be doubled in the next year. Gradually increase the N:P2O5:K2O dose to 500:250:1000 g/plant/year to obtain full dose from 15th year onwards.

Harvesting
Fruits are available throughout the year, but the peak period of harvest is from December to May. When fruits are fully ripe, the nuts split open. These are either plucked from the tree or allowed to drop. The two major products are nutmeg and mace. Dried nutmeg and mace are directly used as spice and also for the preparation of their derivatives.

After de-rinding the nutmeg fruit, red feathery aril (mace) is separated from pericarp. The mace is detached, flattened and dried in sun on mats for 3-5 days.

The nuts are dried in the sun for six to eight days till they rattle in their shell. They are stored in warm dry place prior to shelling.

Oleoresin
Nutmeg and mace oleoresins are prepared by extracting the ground spice with organic solvents. Yield of oleoresin is 10-12 per cent for nutmeg and 10-13 per cent for mace. Mace oleoresin possesses a fine, fresh fruity character.

Nutmeg butter
Nutmeg contains 25-40 per cent of fixed oil that can be obtained by pressing the crushed nuts between plates in the presence of steam or by extracting with solvents. The product, known as nutmeg butter, is a highly aromatic, orange coloured fat with the consistency of butter at ambient temperature.

Nutmeg oil
This is obtained as pale yellow to white volatile liquid possessing a fresh warm aromatic odour. The yield ranges from 7 to 16 %. The unshelled nuts are coarsely crushed in a mechanical cracker and steam distilled.

Mace oil
The mace yields 4-17 % colourless to pale yellow liquid possessing organoleptic properties similar to nutmeg oil. Nutmeg and mace oil are also used for flavouring.

Pests
The hard scale Saissetia nigra occurs on the pencil thick branches and desaps the tissues. The infested shoots invariably develop sooty mould cover. It can be controlled by spot spraying with quinalphos 0.025%.

Diseases

Leaf spot and shot hole (Colletotrichum gloeosporioides)
Sunken spots surrounded by a yellow halo are the initial symptoms. Subsequently the central portion of the necrotic region drops off resulting in shot hole symptoms. Dieback symptoms are also observed in some of the mature branches. On young seedlings drying of the leaves and subsequent defoliation are seen. The disease can be controlled by spraying 1% Bordeaux mixture two or three times during rainy season.

Fruit rot
This is caused by Colletotrichum gloeosporioides and Botryodiplodia theobromae. Water soaked lesions are seen on the fruits, the tissues of which become discoloured and disintegrated. Premature splitting of the pericarp and rotting of mace and seed are the main symptoms of the disease. The internal tissues are found rotten. The fallen fruits become enveloped with the growth of the organism. The disease can be controlled by spraying 1% Bordeaux mixture.

The other diseases include leaf blight (Botryodiplodia theobromae), leaf spot (Alternaria citri), sooty mould (Phragmocapnius sp.) and the algal leaf spot (Cephaleuros sp.).