CROP HUSBANDRY- ARECANUT CULTIVATION PRACTICES IN KERALA

ARECANUT (Areca catechu)

The arecanut palms grow under a variety of climatic and soil conditions. It grows well from almost sea level up to an altitude of 1000 m in areas of abundant and well-distributed rainfall or under irrigated conditions. It is grown in a variety of soils such as laterites, red loams and alluvial.

Varieties
Mangala, Sumangala, Sreemangala and Mohitnagar.

Selection of site
Select sites with deep well drained soil without high water table. Provide adequate irrigation facilities.

Selection of mother palms
Select mother palms showing earliness and regularity in bearing, high percentage of fruit set and semi-tall to dwarf in stature.

Selection of seed nuts
Select fully tree-ripe nuts from middle bunches during midseason. Discard nuts, which are undersized, malformed and low in weight.

Nursery techniques

Sow selected seed nuts soon after harvest in nursery bed with stalk-end up and with a spacing of 5-6 cm. Cover the seed nuts with sand and irrigate daily.

Transplant 90 day old sprouts having 2-3 leaves to the secondary nursery. Prepare secondary nursery beds of 150 cm width and of convenient length. Apply cattle manure @ 5 t/ha as basal dose. Transplant sprouts at a spacing of 30 x 30 cm. Provide shade by growing banana, Coccinia indica etc or by means of artificial pandal. Plant banana in advance at a spacing of 2.7 x 3.6 m when it is grown as a shade crop. Provide irrigation during hot and dry periods and drainage during monsoon. Periodical weeding and mulching are necessary.

Selection of seedlings

Select good seedlings for transplanting in the main field when they are 12-18 months old. Selection of seedlings can be based on the selection index. Multiplying leaf number by 40 and subtracting the seedling height gives the selection index. Select seedlings with higher selection index values.

Example:

Seedling height = 90 cm, Leaf number = 5.
Selection index (5 x 40)-90 = 110
(If for instance, index values range between 50 and 150, select seedlings with higher values to the extent possible). Remove seedlings with the ball of earth attached to them for transplanting.

Note: Plant characters such as girth at the collar one year after transplanting and number of nodes two years after transplanting are highly correlated with yield. Removal of plants with poor collar girth and lesser number of nodes one and two years after planting respectively, will help to increase the yield potential of plantations.

Field planting

Plant tall, quick growing shade trees on the southern and western sides of the plantation to provide protection from sun scorching.

Plant seedlings in pits at a spacing of 2.7 m x 2.7 m with north-south alignment, the rows being deflected at an angle of 35º towards west. Dig pits of size 60 x 60 x 60 cm and fill up with rich topsoil to a level of 15 cm from the bottom. Plant seedlings at the centre of pit, cover with soil up to collar level and press around.

The planting is to be done during May-June in well-drained soils and during August-September in clayey soils. Banana may be planted between rows to provide shade in the initial stages up to 4-5 years.

Manuring
Apply green leaf and compost, each at the rate of 12 kg per palm per year from first year of planting onwards, during September-October.

Apply N:P2O5:K2O for adult palms @ 100: 40:140 g / palm / year.

Apply 1/3 dose during first year, 2/3 dose during second year and full dose from third year onwards. Under irrigated conditions, apply fertilizers in two split doses, the first during September-October and the second during February. Under rainfed conditions, apply the second dose during March-April after the receipt of summer rains. Apply manures and fertilizers during September-October in circular basins of 15-20 cm depth and with a radius of 0.75-1.0 m from the palm. Apply the second dose of fertilizers around the base of palm after weeding and mix into soil by light forking. In acidic soils, broadcast lime at the rate of 0.5 kg per palm once in two or three years and incorporate into soil by forking during March-April.

Irrigation and drainage

Irrigate the palms during hot and dry periods at regular intervals of 3-5 days depending upon the soil type.

The palms should be irrigated once in four to seven days depending on the soil type and climatic factors. In west coast, where major area of arecanut gardens are irrigated, watering the garden once in seven or eight days during November-December, once in six days during January-February and once in three to five days during March-April-May is recommended. In each irrigation, give about 175 litres of water per palm. Where there is shortage of water, follow drip irrigation. Application of organic mulch to the garden helps conservation of soil moisture.

Construct drainage channels (25-30 cm deep from the bottom of pits) between the rows and drain out water during periods of heavy rainfall to prevent waterlogging.

Cultural operations

Keep the garden free of weeds and break up surface crust by light forking or digging after cessation of monsoon during October-November. In slopes, prevent soil erosion by terracing. Sow seeds of green manure-cum-cover crops such as Mimosa invisa, Stylosanthes gracilis and Calapagonium muconoides in April-May with the onset of pre-monsoon rains. Cut and apply them to the palms in September-October.

Intercropping and mixed cropping
Crops such as elephant foot yam, pineapple, pepper, betel vine, banana, guinea grass, cocoa, ginger and cardamom can be grown in arecanut gardens. While planting cocoa, a spacing 2.7 x 5.4 m is recommended. In all cases, the intercrops should be manured adequately and separately.

Plant protection

Pests

Mites
Orange coloured mites can be controlled by spraying the bunches with dimethoate at 0.05 per cent.

Spindle bug (Carvalhoia arecae)

The feeding injury is caused on the lamina and petiole. The affected leaves show dry brown patches.

Spray crowns with carbaryl 50 WP. The spray should reach the leaf axils. Repeat spraying after 30-35 days if pest incidence continues. Placement of 2 g phorate 10G sachets on the top most two leaf axils prevents the pest attack.

Inflorescence caterpillar (Batachedra sp.)
Force open the inflorescence out of the enclosing spathe and spray malathion 50 EC (250 ml in 100 litres of water). Control slugs, which predispose inflorescence to the attack of caterpillar, by using bait of metaldehyde.

Root grub (Leucopholis burmeisteri)
Loosen soil around the base of palms to a depth of 10-15 cm and drench with chlorpyrifos 0.04% suspension twice, one in May just before the onset of southwest monsoon and again in September-October towards the close of the monsoon. Repeat application for 2 or 3 years consecutively to secure a complete eradication of the pest. Root grubs can also be controlled by soil application of phorate 10G around the palms.

Diseases
Koleroga (Mahali or fruit rot) (Phytophthora palmivora)
Spray Bordeaux mixture 1% on all bunches three times in a year, one just before the onset of southwest monsoon and the rest at 40 days intervals. If monsoon season is prolonged give a third spray. Use rosin soda adhesive to ensure tenacity of the spray deposit on treated substrate. Remove and burn all fallen and infected nuts.

Bud rot (Phytophthora palmivora)
Remove and destroy affected spindle and leaves. In early stages of infection, scoop out affected rotten tissues by making longitudinal side splits and apply Bordeaux paste on the exposed healthy tissues or drench crown with 1% Bordeaux mixture.

Basal stem rot (Anabe) (Ganoderma lucidum)
1. Isolate affected palms by digging trenches 60 cm deep and 30 cm wide around, one metre away from the base and drench with captan (0.3%), calixin (0.1%) or copper oxychloride (0.3%)
2. Remove and destroy all severely affected palms and stumps of dead palms.
3. Drench the soil with 1% Bordeaux mixture before planting healthy seedlings.
4. Discourage growing of collateral hosts of fungus such as Delonix regia and Pongamia glabra in the vicinity of gardens.
5. Apply 2 kg neem cake per palm.
6. Avoid flood irrigation and water flowing from infected palms to healthy palms.

Yellow leaf disease
Maintain the garden properly to keep affected palms in a healthy condition by adopting recommended manurial, cultural, plant protection and other management practices. Improve drainage conditions in the garden.

Disease management

1. Apply the recommended dose of fertilizers.
2. In addition to the above, apply 160 g of rock phosphate per palm in the affected garden.
3. Apply organic manure @ 12 kg each of compost and green leaves per palm per year.
4. Provide irrigation during summer months
5. Avoid water stagnation in the garden by providing drainage facilities.
6. Grow cover crops in the garden.
7. When only a few palms are affected in a garden, remove them to prevent further spread of the disease.
8. Adopt need based plant protection measures against pests and diseases.

Band disease
Improve soil conditions by loosening hard soil strata, if present, by providing good drainage. Adopt adequate control measures against spindle bug, mealy bugs, scales and mites. Where the results of the above treatments are not found satisfactory, apply powdered mixture of copper sulphate and lime in equal quantities @ 225 g/palm twice a year at the base of affected palms. Application of borax @ 25 g/palm has been found to have an ameliorative effect.

Collar rot of seedlings
Improve drainage conditions in nursery beds and gardens. Drench spindle and base of seedlings with 1% Bordeaux mixture in disease affected nursery or garden.

Dieback of inflorescence
Remove affected inflorescence immediately. Spray zineb (4 g in 1 litre of water) or mancozeb (3 g/l) twice, once just after female flowers are set and again 15-28 days later. Aureofungin sol at 50 ppm concentration is also effective in controlling the disease.

Stem bleeding
Palms in the age group of 10-15 years are more prone to this disease. Symptoms appear on the basal portion of the stem as small discoloured depression. Later, these spots coalesce and cracks develop on the stem leading to disintegration of the fibrous tissues inside. With the progress of the disease, a brown exudate oozes out from these cracks. High water table predisposes the palm to this disease.
Improvement of drainage and root feeding of 125 ml tridemorph (1.5%) is suggested as control measure against this disease.

Sun scorch
Protect palms from southwest sun by wrapping stems with areca sheath or white-wash the exposed portion. Provide reinforcement to palms showing stem fissures. Grow tall, quick growing trees on southern and western sides of garden.

Nut splitting
This can be considered as a physiological disorder than a disease. Palms in the age group of 10-25 years are more susceptible. Symptoms are premature yellowing of the nuts when they are half to three-fourth mature. Later splits develop at the tips, which extend longitudinally exposing the kernel. Sometimes kernel also show splitting and malformation. Rarely the kernel inside may exhibit splitting without visual symptoms on the husk, resulting in nut fall. Hyper nutrition or sudden flush of water after a period of drought or insufficient moisture in the soil is the probable cause (s) of the disease.

Improvement of drainage in ill drained gardens and spraying of borax @ 2 g/litre of water are found effective in reducing the disease incidence.

Post-harvest technology
A simple de-husking device has been standardized by the CPCRI, Kasaragod. The out turn with this device is 60 kg of husked nuts in the case of dry nuts and 30 kg in the case of green nuts. The cost of the device is about Rs 250.