Monday, September 29, 2014

Mango cultivation in srilanka


Introduction
Mango, popularly known as the king of fruit, belongs to Anacardeaceae family of trees. Taste, flavor and fragrance of mango is very characteristic to the same.

Mango was originated in India. Though it is not endemic to Sri Lanka, it is seen growing in many parts of the country. It is very rare to find a home garden without a mango tree in our country except in certain upcountry areas. Present extent under mango in Sri Lanka is about 27,500 Ac. Predominately, it is grown in Kurunegala, Anuradhapura, Hambanthota, Puttalam, Moneragala, Jaffna districts and in Mahaweli Systems H & C. As a fresh fruit, mango has a high demand in local markets. Likewise, a considerable amount of foreign exchange could be earned by exporting both fresh and processed mango products.

At present Sri Lanka export about 80,000 Mt. Therefore, plans are under way to increase the extent under mango to about 17, 481 Ac by year 2000.

Nutritional Aspects
Nutrient level per 100g of mango flesh
Water 
81.0 g
Energy 74 k cal
Protein 0.6 g
Lipids  0.4 g
Carbohydrates 16.9 g
Calcium 14 mg
Phosphorus 16 mg
Iron 1.3 mg
Carotene 2743 micro g
Thiamin 80 micro g
Riboflavin 90 micro g
Niacin 0.9 mg
Vitamin C 16 mg
Consumption of a medium size mango could provide the daily requirement of Vitamins A and C. The level of various nutrients may vary depending on the cultivar, ripeness of the fruit and area of cultivation.

Mango is consumed as ripe and unripe fresh fruit as well as various processed products. Pickles and chutneys are made from unripe mango. Different types of drinks, jams, jellies are prepared using ripe fruit. Likewise, dried and dehydrated mango pieces and mango powder is also seen in the market.

Medicinal properties

Both unripe and ripe mango has medicinal properties. A drink made out of unripe mango is used as a remedy to prevent various body ailments caused by a raise in ambient air temperature. Unripe mangoes are also used in treating stomach problems and to stimulate bile formation and in treatment of blood related diseases.

Ripe mango has many medicinal properties. Consumption of ripe mango is useful to overcome night blindness and to protect health of skin. There is a common belief that consumption of ripe mango with cows milk helps gain weight.

Mango seeds, leaves and bark are used in the treatment of diarrhea and disorders in reproductive system of women.

Recommended Varieties
There are a wide range of mango cultivars presently grown in Sri Lanka. Out of these, a number of best cultivars have been identified for cultivation under various agro-ecological regions of the country. Use of such adaptable varieties is necessary to get a higher yield from a mango tree. Fruit of different varieties have its own characteristic flavor and taste.

Cultivars recommended for various agro-climatic regions of the country
Dry Zone Karuthakolomban
Willard Vellaicolomban,
Ambalavi,
Chembatan,
Malwana(Underground)
Intermediate Zone Karuthakolomban
Vellaicolomban
Willard
Bettiamba
Malwana(Underground)
Wet Zone Vellaicolomban
Gira amba
Peterprasand
Dampara

Preparation of budded plants

Rootstocks must be raised first to produce budded mango plants. It is much better to use seeds extracted from ripe fruit of cultivars Kohu amba, Wal amba, Walu amba and Gira amba etc..

At first, remove the husk of the seed. Make a small cut at the distal end of the seed and pull the husk away to get the seed inside without any damage to it. When the cut is made at the distal end of the seed with husk, even if it cuts the seed inside, it does not damage the embryo.

Extracted seeds may have mango weevils inside. When such seeds are planted, whole seed may be destroyed. Therefore, dip the seeds in an insecticide solution such as 'Dimethoate' before planting for a few minutes. Use of fungicides such as 'Captan' at this time is helpful to protect the seeds from fungal infections at the nursery.

Seeds treated with insecticide and fungicide solution must be planted in a sandy seed bed. For the seed bed, use a 15-20 cm thick layer of sand. Sand beds must be laid out in a place with slight shade. However, never under trees such as mango or avocado. Then it is easy to protect the seedlings from certain fungal diseases.

In the sand bed plant seeds in a row spaced 15-20 cm apart. Curved side of the seed must be downward at planting. Spacing of 2-3 cm is allowed between two seeds in a row.

After seeding, keep the sand bed moist at all times. Seeds germinate and seedlings emerge 10-14 days after planting. About three weeks after emergence, seedlings are suitable for transplanting in polyethylene pots or any other secondary nursery.

If a media such as coir dust is used for germination of seeds, care must be taken to maintain the appropriate moisture level. At high moisture levels, seedling may be infected with fungal diseases. Plants hardened in the seed bed may be transferred to polyethylene pots filled with a suitable media. Else plants may be transplanted well prepared secondary nursery.

Planting in polyethylene pots

Use pots made out of 200 gauge polyethylene to a dimension of 20 cm (8?) diameter and 30 cm (1 ft) height.

Potting mixture is prepared by mixing equal parts of topsoil, sand and well composted cow dung or leaf litter together. Use of one part of coir dust to four parts of above mixture is helpful to improve the water holding capacity of the potting media.

Fill the polyethylene containers with the above mixture. Fill media only to leave 2-3 cm from the top of the container. This is necessary to prevent overflow of water when pots are irrigated.

Planting in a secondary nursery

If seedlings are not directly transplanted on a pot, it must be transferred to a secondary nursery. To make a secondary nursery, prepare beds about 20 cm in height filled with a mixture of top soil and well composted cow dung. Have a drain between two beds to improve drainage.

Double row system of planting must be adopted in the secondary nursery. In a single bed, two double rows are planted (four rows of seedlings). A spacing of 45 cm is allowed between two double rows 30 cm is recommended within the double row with triangular system of planting.

Plants in secondary nursery of polyethylene pots become ready for grafting 7-8 months after transplanting. The stem of the stock plant must attain pencil thickness before grafting.

Selection of scion

Take scions only from mother trees having good fruit quality characteristics. For this purpose use trees giving fruit with quality specific to the cultivar and that bears well annually.

Scion wood must be collected from branches bearing fruit. Avoid use of water shoots.

As for budding, a bud just below the apical bud of the scion wood is used. Grafting is done with a piece of shoot with apical bud.

Methods of budding

Both patch budding and grafting can be adopted for mango. Patch budding is more suitable for the wet zone while grafting is suitable for the dry zone.

For grafting, shoots with mature leaves around apical bud is the most suitable. Before grafting, the shoots must be conditioned.

One week before grafting, remove all the leaves in the selected scion wood. Then cut the defoliated scion stick to about 10-15 cm length. The basal end is axed to form a wedge. In the rootstock, cut back the plant at a place where stem thickness is equal to that of the scion wood. Then carefully split the stock stem stump down and insert the scion and tightly wrap the union with a polyethylene tape.

To prevent drying off of the scion wood, cover it with a polyethylene bag. Or else keep the grafted plants inside a propagator. These kind of measures will ensure a high success rate of grafting.

For budding, use a piece of bark with a single bud collected from a fruit bearing shoot of a selected mother tree.

Remove a rectangular shaped piece of bark at 20-25 cm height of the stock plant. Then insert the scion with the bud into the stock plant and tightly wrap with a polyethylene tape.

For success of budding it is essential that the size and shape of the scion wood and that of the cut made on the stock plant match closely.

When stock plants taken from seedbed is transplanted into polyethylene pots directly and grafted, a plant ready for field planting can be produced in 7-8 months. However, when stock plants are transferred to a secondary nursery and graft, it takes about 16 months to produce a plant ready for field planting. Thus the cost of production of such plants increase invariably.  

Climatic requirements

Mango tree is well adopted to tropical and subtropical environmental conditions. It can be cultivated until up to 1300 m above mean sea level. However, commercial cultivations are limited to areas below 600 m above mean sea level.

Optimum temperature for mango cultivation is 27-30C. Mango is successfully cultivated in areas where annual rainfall range from 500-2500 mm. For a successful crop, most important thing is the distribution of rainfall rather than the amount.

A dry period of 3-4 months is an essential prerequisite for successful flowering of mango. Rains at flowering may affect yield due to pollen wash off.

Soil

Mango can be cultivated in a wide range of soil conditions. A well drained soil with 2 M depth is the best. Soil pH must be 5.5-6.5. Soils with high clay content or with frequent water logging is not suitable for successful cultivation of mango.

Field preparation
Mango is cultivated both as a home garden crop and a commercial scale crop. Before establishment of a commercial cultivation, clear the land and plow and harrow. At the same time, take steps to adopt appropriate soil conservation measures.

Spacing

- Within row (m) Between row (m)
For Willard  7 10
For Other Cultivars  10 10

For the particular cultivar of interest, stake out land accordingly. In a land with a loose soil, a planting hole measuring 60 cm x 60 cm x 60 cm is sufficient. For heavy soils use of 90 cm x 90 cm x 90 cm planting holes recommended.

Fill the planting hole with well composted organic materials and top soil two weeks before planting. Heap the soil to about 6 inches above the ground level over the planting hole.

Planting materials

Budded planting materials are recommended for planting. Use of these planting materials ensure the preservation of fruit quality characteristics of the cultivar, early bearing and ease of crop husbandry in the mango cultivation.

It is advisable to use planting materials certified by the Department of Agriculture. Those planting materials are sold with a label indicating the cultivar name and a number of identification on it.

Whenever seedlings are used as planting materials, it takes along time to bear. Also it is difficult to guarantee the fruit quality characteristics of the cultivar.

Time of planting

Planting can be commenced with the onset of Maha rains in the dry zone. In intermediate and wet zones, planting is possible with onset of Maha or Yala rains.

For a home garden, planting is possible at any time of the year except during periods of heavy rains. If a prolonged dry condition exists, plants must be irrigated as and when necessary.

Use only very vigorous plants for field planting. Minimize the stress during field planting by hardening plants exposing to direct sunlight and with less water application. This hardening held improve the success rate of field establishment.

At planting remove the cover. Cut around the edge of the bottom of the pot and remove the intermingled roots by pruning tap root.

  • Place the plant in such a way that the base of the plant in the pot is aligned with the ground level. Then remove the polyethylene bag with two longitudinal cuts from bottom up.
  • After removing the polyethylene cover, fill the planting hole with soil and slightly tighten the soil. These steps help reduce root damage due to breaking and splitting of potting media block.
  • Allow the plant to grow directly up. Use a stick closer to the plant and tighten it into the stick carefully. - To minimize water loss under dry weather conditions, remove half of each mature leaf.
  • Use a mulch around the plant using easily available mulching material such as dry grass or salvenia. Mulching helps to reduce soil temperature in the root zone. Weed control also become easy. It also reduce drying of soil and wind erosion of soil.
  • After planting watering is an essential requirement. Construct a basin around plants to control runoff of applied water.
  • Provide shade appropriately to protect plants from heavy sunlight.

Crop Management

Training of treesTraining gives a tree good appearance, management of the tree becomes easy, high yields with quality fruit is possible and pest and disease incidence minimized. Training of trees must be started right from the early stages of growth. Pay special attention to train trees from the time of planting.

Allow a plant to grow as a single stem up to about 1/2 M. Let the first branch form at 1/2 M height. Then at about 15-20 cm spacing allow to grow 3-4 branches around the tree. Let these branches to grow in opposite directions to give a tree a good appearance. This is also important to minimize break of branches at latter stages of growth. Natural shading of branches also minimized when branches are equally well distributed around the tree.

Shoots that do not receive sufficient sunlight do not produce enough food reserves for the tree. Thus, fruit set in such branches are not satisfactory. Such branches must be removed. Also diseased, dead and intermingling branches must be removed. In removing branches the cut must be very close to the main stem or limb when pruned. Prune trees under dry weather conditions. Apply a paint mixed with a fungicide to the cut surface.

Weed Control

It is not essential to weed the whole land area in a mango cultivation. Most important thing is to keep the area around the base of the tree weed free. Thus keep only the area under canopy cover weed free by use of a mamoty. However until the end of first year after planting, it is important to have an area extending up to about 60 cm away from the tree without weeds. During this period use dry grass as a dead mulch.

Use a slasher to move down the weeds among trees. In doing so the grass in this area can be maintained as a live mulch. Then erosion due to wind and rain can be countered.

IrrigationSpecially in areas when prolonged dry periods exist, it is imperative to irrigate the plants in the first three years after planting. Frequency and amount of irrigation depend on rainfall and soil properties.

For mango the most critical periods of moisture requirements from flowering to fruit maturity and leaf bud burst to leaf maturity.

From leaf maturity up to flower bud burst irrigation must be withheld. Irrigation during this period adversely affect flowering.

Fertilizer application
Wet Zone

Un-bearing trees
Annual dose of fertlizer per plant (g)
- Urea      Rock Phosphate MOP   
At planting  115 230 105
A year later 115 230 105

Thereafter, until the bearing stage, use the above mixture with annual increments of 60g urea, 115g rock phosphate and 55g of muriate of potash.

Bearing treesAnnual fertilizer dose per plant (g)
- Urea Rock Phosphate MOP
At fruiting 215 325 380

Thereafter, until the bearing stage, use the above mixture with annual increments of 110g urea, 165g rock phosphate and 190g of muriate of potash.

After several years the maximum recommended dose per tree is 870g urea, 1295g rock phosphate and 1515g of MOP.

Dry and Intermediate Zones

Unbearing trees
Annual dose per plant (g)
- Urea TSP MOP
At planting 160 195 90
A year later 160 195 90

Thereafter, until the bearing stage, use the above mixture with annual increments of 80g urea, 100g rock phosphate and 45g of muriate of potash.

Bearing trees

Annual dose per plant (g)
- Urea TSP MOP
At fruiting 235 160 515

Thereafter, until the bearing stage, use the above mixture with annual increments of 120g urea, 80g TSP and 260g of muriate of potash.
After several years the maximum recommended dose per tree is 945g urea, 630g rock phosphate and 2055g of MOP.

Other cultural practices
Wind breaks

Before establishment of a large cultivation, plant trees like gliriceedia or ipil-ipil along the border of the land. This is particularly important in areas where heavy winds prevail.

Termite damage

During dry periods, termites may damage underground parts of the tree. To overcome this problem apply a band of engine oil on the base of the stem up to about 45 cm height.

Fire protection

In the dry zone heavy winds blow July through August. Most cultivated lands are damaged by fire at this time of the year. To protect the mango cultivation by spreading fire, have a 5-10 M wide fire belt around the orchard plowed and harrowed to remove dry grass. Also during the dry months of the year keep an area of about 3 M around the base of trees weed free. This might protect trees even if a fire spread over the orchard.

Removal of stock shoots and flower buds

After planting grafted trees, never allow to grow buds from any other area except from the grafted bud or shoot. If allowed, the growth of the grafted shoot will become weak and may die back latter.

All flower buds that emerge at early stages of growth must also be removed. This is particularly important for trees showing poor growth. In such trees, continually remove flower buds up to the end of third year. This precocious flowering is mostly seen in cultivar Willard.

Thinning out of fruit

A tree can sustain a certain number of fruit depending on its size. If more fruit are set than this, those fruit may drop naturally. In certain instances, however, even after natural fruit drop, a large number of fruit may remain on the tree and due to this only a few fruit will set in the following year. For a commercial cultivation, this is not a good thing to happen.

For varieties like Karuthakolomban and Vellaicolomban, leave only one fruit a panicle while cultivar Willard can have 4-5 fruit per panicle and remove all other excess fruit. This is important to minimize yield variation over the years. Also it is helpful to obtain a higher proportion of well grown high quality fruit every year.

Insect pest control
Fruit fly (Bactocera dorsalis)
Adult is brown in color. Dark yellow spot seen on the thorax. It is 8 mm long and wing span is about 15 mm.
Female fruit fly lay eggs inside the peel of fruit after piercing it. Developing larvae use the fruit flesh as food. As a result fruit flesh melts and become unsuitable for consumption. Fungi causing fruit rot may also enter the fruit from the pierced whole adults made to lay eggs.
Infested fruit develop brownish rotting spots on fruit surface. Such fruit drop quickly.

Control:

  • Remove all dropped fruit and destroy.
  • Before dispatch fruit to the market, dip fruit in 40C water for 20 min.
  • Use methyl eugenol traps to trap and destroy fruit flies. Use traps fro flowering through harvesting stage

Five traps are sufficient per acre. Remove all trapped insects fortnightly. Also replace the chemical occasionally.
Spray a suitable pesticide from time of flowering . Fenthion is recommended at 30 ml in 10 l of water. Stop spraying at two weeks before harvesting.

Mango leaf hopper

Amritordes brevistylis
Ideoscorpus clipealis
Ideoscorpus neveaspardis

This plant hopper is about 4 mm in size and is a very active insect. It lives all year round among leaves and in stem crevices and the population explode during the dry season. At this time if a person goes under a infested mango tree, a characteristic sound can be heard due to the activation of hoppers.

Adults lay eggs on flower buds and on developing young leaves. Instars suck plant sap and due to this flowers and leaves dry off. This affect the fruit set and fruit yield severely.

Hoppers excrete a sticky sugar rich solution and when that falls on leaves and other parts of the tree, a black mold grows on such surfaces. Affected leaves and flower panicles turn black in color. Nor fruit set on such panicles too. When the mold grows on fruit, their marketability drops. Under heavy infestation total crop failure is a possibility.

Management:

Train trees properly and prune excessive foliage and branches. Then penetration of light inside of the canopy checks the growth of hopper population.
At flushing and flowering use one of the following chemical sprays.
Dimethoate 30 ml in 10 l water
Imidacloprid 10 ml in 10 l water

Mango seed weevil (Sternocatus mangiferae)

An insect of about 1 cm long and reddish brown to ash in color. It is a nocturnal insect and it can fly. Adults lay eggs on immature fruit under the peel. Larvae cross the fruit flesh and enter into the seed of the developing immature fruit and use the developing seed as the source of food. Weevil comes out of the husk after seeds left out of fruit after consumption and live inactively on stem crevices and other dark places of the tree.

Path crossed by the larvae through the fruit flesh is not discernible at ripening stage. This is however affect the germination of the seed and thus it is a pest of primary importance to nurserymen.

Control:

Remove and destroy all dropped fruit at various stages of growth. At flowering spray Dimethoate at 30 ml/10 l water in such a way that all leaves and developing fruit get wet.

Leaf cutting weevil

Adult insect is ash brown-black in color. It is about 5 mm long and 2 mm wide. Weevil cuts the leaf on tree leaving about 1/4 of it on the tree. The fallen leaf pieces can be seen under the tree. Adult insect eats the other remaining leaves on the tree. This create wholes on leaf blade. Due to this damage, growth of plants may be affected.

Control:

  • Remove and destroy all fallen pieces of leaves.
  • Spray Dimethoate at 30 ml in 10l water at the time when damage is first observed.

Disease control

Anthracnose

Colotritricum gloesporiodes is the causative agent of this disease.

This disease is prevalent in every mango growing area of Sri Lanka. Leaves, flower panicles and all stages of developing fruit may be affected by this disease. During hot humid weather conditions, the severity of the disease is higher. Different varieties may have ability to resist this disease.

SymptomsOn developing leaves the emergence of small dark brown or black spots is the first stage of infection. With the passage of time, these spots will grow and unite each other to form irregular shaped brownish black spots. Newly emerged leaves are more susceptible to Antracnose. If severely infected, die back of shoots possible. This is frequently observed on mango nurseries.

When flowers contract Antracnose, panicle will turn black in color and dry off. Due to this all flowers in the panicle may be lost.

Small developing fruit turn black in color, dried off and fall. Mature fruit shows small dark brownish spots at the beginning . As the fruit mature these spots grow in size and turn into black irregular shaped patches. Infected fruit shows rotting at the surface. Such fruit are unmarketable.

Fungal spores on infected fruit and flowers wash off during rains and get deposited on developing fruit which cause formation of small disease spots. After harvesting, as the fruit ripens its natural resistance to the disease fades away. Therefore, fungus present on unripe fruit as a latent infection begins to develop rapidly as the fruit ripens.

However, after harvesting it is very rare to observe spread of disease to a fruit by another infected fruit.

Management of Antracnose
  • Prune excess foliage to allow penetration of sun light inside of the canopy.
  • Use on of the fungicides listed below just before and after flowering. For effective spray penetration onto leaves and flowers, use a nozzle connected to a rubber tube fixed to a wooden pole.
Fungicide Mixture
Benlate 6g /10 l water
Daconil    20g/10 l water
Maneb    20g/10 l water

Dip fruit at least with in 24 hr. after harvesting in hot water at 50C for 5 minutes. For this purpose mix 100g Benomil per 100 l of water. However, care must be taken to control water temperature properly to avoid any damaged to fruit.

Stem End Rot

A disease of importance in harvested fruit. A number of fungi including Ladiodiplodia theobromea, Coletritricum gloeosporiodes and Fotogercis mangiferea cause the stem end rot disease in mango. Disease symptoms develops around the stem end of the fruit as it begins to ripen after harvesting.

Fungal spores are prevalent on dead leaves and twigs in orchards. As the spores spread on to flowers and fruit before harvesting, the fungi may form latent infection on fruit.

Symptoms

Symptoms become clear as the fruit ripens. At the stem end of the fruit, brownish patches begins to develop. Due to this both the peel and the inside flesh begins to rot. Infected fruit also gives a bad smell.

Management

In cultivations where this disease is severe, adopt a spray program from the time of flowering. Use Benlate at the rate of 6g in 10 l water. Sprays must be repeated in 14 day intervals. In addition,

Never let leaves and twigs to fall and rot near the trees.
Avoid harvesting fruit that is not sufficiently mature.
Use hot Benlate dips as recommended for Antracnose control above.
Store harvested fruit at a low temperature.

Harvesting & Post-harvest Technology
Harvesting

Grafted plants commence bearing 3-4 years after planting. Fruit need to be harvested only after it mature sufficiently, but before ripening. In most cultivars, when fruit is mature enough, the color of peel change from dark green to light greenish yellow in color. However, to ascertain the level of maturity a number of fruit should be picked randomly, cut and inspected. If fruit show a yellow color around the seed, they are mature and ready for harvest. If the flesh color is white, it is not yet ready for harvest.

Hand pick fruit if possible. Else, use a wooden pole with a hook or knife attached with a cloath bag or net below. This prevent bruising and fruit injury. Never let fruit fall on the ground.

There is a simple device for harvesting as given above. As shown in the figure, it is fabricated with 1 mm galvanized iron and below the tooth-shaped ring is a pouch made out of fish net or cloath. Pedancle of the fruit is inserted in between the teeth and make sure the fruit is inside the pouch and pull the pole. Detached fruit is then fall into the pouch.

To minimize sap exudation, harvest fruit between 9 AM - 3 PM. Avoid humid rainy weather conditions at harvesting.

Yield

Age of tree Fruit Number per tree
5-8 450
9-10 800
11-25 1250

Handling harvested fruitNever leave harvested fruit under direct sun. Take those to the pack house safely. Thereafter, sort fruit to remove damaged, cut and bruised, immature and over-ripe fruit.

Wash sorted fruit in a water bath with Benomyl or Thiobendazol. This is important to remove sap on the fruit and to give it a good appearance. Due to the action of fungicide, development of diseases like Antracnose is checked.

However, for effective control of post harvest diseases, 1-3 min. dip in 52C water is more suitable. This can be done with or without fungicide. If a fungicide is not mixed with hot water, spray a solution of 1% fungicide on washed fruit.

Packing

Before packing fruit may be sorted again. At this time if there are any unmarketable fruit, those are discarded.

For export purposes, selected fruit is packed according to size. For European markets, high demand exist for fruit weighing 200-250g. However, sort and pack fruit according to the requirements of the buyer.

Pack fruit in cardboard boxes as a single layer of fruit to about 4-5 Kg in weight per box. Each fruit should be wrapped to polyethylene or shredded paper and pack in the box.

Storage

At ambient air temperature, mangoes harvested at correct stage of maturity can be stored for about 8-12 days. Under cold conditions at 12C , storage life can be further extended up to 25 days without loosing fruit quality.

Transport For local markets, damages caused at shipping is not duly taken care of. Therefore, losses are very high. Hence, it is important to pack fruit in appropriate containers and transport safely.

For export, air freight is the most common method of transport. The reason for this is that fruit can not be stored for a long time.

Economics & Marketing
Labor requirements

Labor requirement for the first year to establish 1 Acre of systematic mango cultivation.
Item Man days
Land preparation/Soil conservation 14
Staking and holing  04
Application of manure and basal fertilizer    04
Planting  02
Shading    01
Fertilizer application/weed control  01
Irrigation  12
Orchard maintenance  04

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