Litchi Fruit Production Part -2
January 23, 2013
Vegetative propagation : Air layering is also called “marcotting” in china and “gootee” in Pakistan About 2 cm wide ring of bark is removed just below a bud from a healthy and vigorous twig about one year old and 2.5-4.0 cm across. The cut is then surrounded with a mud ball containing sphagnum moss (2 parts of damp moss and 1 part of soil from the foot of old litchi tree is best suited) and wrapped with a polythene sheet. Both ends are tied with fine rope or rubber bands to make it practically air tight. When sufficient roots are formed in about 2 months, the branch is cut below the soil or sphagnum moss and potted in a nursery. July and August is the most appropriate time. After removing the air layers (marcotts) from the mother plant, it is desirable to provide some moist or humid atmosphere by sprinkling water mist for further 2 or 3 weeks. It is necessary to cut back the top of the branch, so as to secure a proper proportion of leaves to root. At least 6 months old marcotted (air layered) plants should be planted in the permanent field preferably in monsoon (rainy season).
Indole Buteric Acid (2-10 g/litre of water) is the most effective in root promotion in air layering of litchi.
Planting is not advisable when the weather is either too dry or too wet.
The details of planting operations are given below :
|Planting Time||March –April, July AugustPlanting may be done in spring and early summer if irrigation facility is available|
|Planting Distance||12 m (both between the plants and rows)8 m (when the climate is comparatively dry and the soil is not so fertile).Average no. of plants- 200 per ha.|
|Size of pits||1x1x1 m (pits are dug a few weeks prior to planting)|
|Filling of pits||Pits are left undisturbed initially for a period of 15-20 days.Filled with top soil mixed with manures and fertilizers @ 20-25 kg FYM, 2 kg bonemeal and 300 g muriate of potash per pitA basket of soil taken from old litchi orchard is added to each pit to ensure mycorrhizal association with litchi roots.Pits are then watered so that the soil settles down.|
|Planting||Square system of planting is usually followed.A small hole is made at the center of the pit and the desired material is planted. Water is applied immediately after planting|
Training and pruning
Training young litchi plants for making a good framework is necessary. Once the desired shape and a strong framework is achieved, pruning is not required, except removing dead or diseased branches and damaged shoots. If trees become too old and produce small sized fruits, pruning heavily improves the yield and quality of fruits.
Manuring and fertilization
In India, litchi is grown mostly in natural fertile soil. A little of no manure is given. The acute shortage of N, P and K seems to stunt all forms of litchi growth, including floral initiation. The fertilizer schedule recommended for litchi for north Indian plains is given in tables 1 and 2.
Fertilizer schedule for litchi in north India
|Age of plant||Fertilizers /plant /year (kg)|
|Farmyard manure||Calcium ammonium nitrate||Superphosphate||Muriate of potash|
|1-3years4-6years7-10 yearsAbove 10 years||10-2025-4040-5060||0.3-1.001.0-2.002.0-3.003.50||0.2-0.60.75-1.251.50-2.002.25||0.05-0.150.20-0.300.30-0.500.60|
Aftercare : Maintenance of good sanitary conditions is must to keep litchi orchards healthy and disease free. Litchi is a deep rooted tree with most of its feeding roots occurring 20-30 cm deep. Therefore, deep tillage is harmful for its plant since it may cause injury to its roots. Tillage operations should be limited up to upper 7-10cm soil layers, whereas deep tillage up to 15 cm during inactive growth phase is advised.
Since litchi is a slow growing tree taking at least 6years to come to flowering and fruiting, intercropping vegetables, pulses and berseem is advised. Some quick growing fruit plants like phalsa and papaya can also be grown in early years of its plantation. The intercrops should be manured separately and protected from pests and diseases.
Weeds are controlled mainly by hand weeding or hoeing which is very laborious and expensive. Applying pre-emergence herbicides diuron or atrazine @ 2 kg /acre at one month interval keeps weeds under control. Use of black polythene mulch also controls weeds more effectively than organic mulch.
Irrigation : January end to the onset of monsoon is a critical period for irrigation since vegetative growth and fruit development take place. Four months prior to normal floral initiation period (December-January) in northern India, the plants should not be irrigated. Though litchi is a deep rooted, perennial fruit crop, the absorbing roots mostly occur in the upper topmost soil layer between 20 and 30cm depths. Therefore, this zone should have 50% soil moisture during the critical period. Young trees should be irrigated by the basin system. As the tree grows, the basin should be gradually enlarged. The fully grown trees are irrigated by flooding or by furrow irrigation, depending on the availability and source of water as per their requirement. The frequency of irrigation ordinarily depends on soil type. Generally weekly irrigation should be given in summer. No irrigation is required during winter in fruiting trees before fruit set.
Mulching : Moisture conservation through mulching using dried weeds or black polythene sheet has been found useful. Trials have also been conducted to conserve moisture using farm residues and polythene sheets. Through adoption of mulching, frequency of irrigation is reduced. In a trial conducted at Ranchi mulching with 3 irrigations was effective in reducing cracking and enhancing yield and quality of fruits (Singh, 1986). To check fruit cracking mulching with 3-4 irrigations during fruit growth has been found to be satisfactory.
Fruit drop : Although fruit drop is not a serious problem in litchi, yet growers have to face a great deal of loss due to fruit drop at different stages of growth and development. Maximum fruit drop occurs during second and third week after fruit set. Fruit drop is varietal character too. The variety ‘Calcutta Late’ bears, the highest number of fruits .I to maturity while ‘Dehradun’ the least. Apart from the I competition among fruits for water and nutrients, strong l winds signifiControl
i. Irrigate bearing litchi trees twice a week from April onwards.
ii. Give protection to trees from strong and desiccating winds by planting the rows of windbreaks.
iii. Spray of NAA 10 ppm will be very effective in reducing fruit drop.
Filler plant and intercropping :Lychee is a slow growing plant and takes about 15-16 years to develop canopy and cover the area. During the initial period of establishment, the space between the plants can be utilized for planting of filler plants/intercrops. The planting of guava, lemon in the centre, between and within the rows of lychee have been found to give additional income in the initial stage of planting without competing with the main crop. Papaya is also planted as filler plant at the spacing of 2.5 x 2.5 m. In between the plants in the initial stage, cowpea, french bean, okra, brinjal or other suitable crops of the regions are grown as intercrops. In the mature lychee orchards, cultivation of partial shade loving plants (ginger, turmeric, ) is practiced successfully, which provides additional income.
Pests of Litchi
Lychee mite (Aceria litchi) is a serious pest in all the lychee growing regions in the country. The tiny nymph and adults stick to the under-surface of the leaf and suck the cell sap. Consequently, the young leaf turns yellow to greyish-yellow and a velvety growth develops on lower surfaces, which subsequently turn brown. The affected mature leaf develops continuous to scattered brown patches with curling, twisting and leathery structure, which ultimately result in blister-like gall formations. It spreads fast under favourable conditions and reduces the photosynthesis activity and increases leaf drop. As a result the tree becomes weak, and yield and quality of the fruit is severely affected. The pest is well studied. It is suggested to prune the affected twigs/branches and burn to avoid spread. Two sprays of karathene 0.05 percent at 7-10 days interval during the attack of the insect has been found to effectively control the pest. Application of neem cake has also been found to reduce the incidence of this pest.
In lychee orchards incidence of shoot borer is reported. The caterpillar bore inside the newly growing shoot and feed on inner parts resulting in drying of the twigs. In the case of severe infestation the sap movement is interrupted and the tree ceases to flush. Pruning and burning of affected twigs minimize the infestation.
Bark eating caterpillar and trunk borer
The caterpillar (Inderbela sp.) bore inside the trunk/main stem. During the night they come out and feed on the bark protected by the large silken webs usually during July-September. The branch ceases growth and the stem becomes weak and may ultimately fall to the ground. The presence of the insect can be known by seeing the excreta and silky web.. Cleaning of the infested area and plugging holes with petrol, nuvacron or formaline soaked material is advocated.
This pest becomes serious especially in humid conditions at the time of ripening. The small caterpillars bore through the stalk end of the fruit, and feed on the seed and skin. As a result fruits become unfit for consumption. The excreta of the caterpillar is seen near the stalk end of the fruit. High humidity and intermittent rains favour the infestation.
Besides the important pests described above, lychee are often affected by leaf eating caterpillars, leaf miners, bugs and aphids.
Birds, bats and bees damage ripe fruits on the trees in China and sometimes a stilt house is built beside a choice lychee tree for a watchman to keep guard and ward off these predators, or a large net may be thrown over the tree. In Florida, birds, squirrels, raccoons and rats are prime enemies. Birds have been repelled by hanging on the branches thin metallic ribbons which move, gleam and rattle in the wind. Grasshoppers, crickets, and katydids may, at times, feed heavily on the foliage.
Squirrels: These cute and highly adaptable tree dwelling rodents are a fun addition to any back yard, unless you have fruit trees. You forever will be in competition with squirrels for your fruit. Squirrels are great fans of lychees and they will plunder all of the fruit in your tree if this situation is allowed to go unchecked. They have a very annoying tendency whereby they take one or two bites out of the fruit and toss them on the ground, where they end up feeding the soil food web and not you.
You can hang “Just One Bite” in the canopy of your tree(s), being very careful to make sure that this peanut butter based rodenticide does not fall on the ground and tempt your household pets. This can be accomplished by wiring chunks of the bait into upper branches. On the other hand you can use “Hav-A-Hart” animal traps to catch squirrels and re-locate them to another more squirrel loving neighborhood.
Weeds : Weeds Compete for water and nutrients during the initial year of growth. Depending upon location more than 25 species of weeds are reported to be present in lychee orchards. Inter-culture operation and mulching suppress the weeds. Herbicides, although found effective for the control, are rarely applied. In mature orchards the weed problem is not encountered due to heavy shade and natural mulching by falling leaves.
Diseases :Lichens and algae commonly grow on the trunks and branches of lychee trees.The main post-harvest problem is spoilage by the yeast-like organism, which is quick to attack warm, moist fruits. It is important to keep the fruits dry and cool, with good circulation of air. When conditions favor rotting, dusting with fungicide will be necessary.
Maturity standard : During maturity acidity declines and TSS increases which corroborate the appearance and colour on the fruit. Thus, the colour of fruit is an important criteria to decide the harvesting stage). The red pigmentation in lychee is associated with anthocyanin pigments which develop better in the direction of good light penetration. Invariably pericarp colour and smoothness of pubicles are the best indicators ,Depending upon the cultivar, 65-80 days are taken for maturity from fruit set.
Harvesting and post harvest management
individually to avoid skin rupturing at the stem end and quick rotting of fruits. They are harvested in bunches along with a portion of the branch and a few leaves. It prolongs the storage life of fruits. Harvesting of litchi is usually done in May and June.
Grading and Packing
After harvesting, fruits should be packed as quickly as possible, as their quality deteriorates markedly, if they are exposed to sun even for a few hours. In packed litchi fruits, air should circulate freely. The damaged, sun burnt and cracked fruits should be sorted and graded properly. There should be only fruits of one grade in a box. Fruits of different varieties should be packed separately. It is better if the box or container is tagged having name of variety and grade. These are lined with litchi leaves or other soft packing material as paper shavings, wool etc. Grading is done according to the size of the fruits. The damaged, sun-burnt and cracked fruits are sorted out before packing. The fruits are graded and packed in shallow baskets or crates lined with leaves of litchi, soft dry grass or banana leaves.
The fruits cannot be stored at room temperature for more than a few days. It loses its bright red colour and turns brown within 2 – 3 days after harvesting. Mature litchi fruits can be stored for a period of 8 to 12 weeks at the temp. of 1.6 to 1.70C and relative humidity ranging between 85 to 90%
The fruit along with twigs is packed and transported by truck to the wholesalers and retailers of the nearest towns. During transit care should be taken to avoid crushing of fruits and damage of the skin. Litchi being a highly perishable fruit, its marketing should be done as early as possible.
Physiological disorder :
Sun burn and skin cracking in developing fruits are two serious problems in litchi. High temperature, low humidity and soil moisture conditions during fruits development promote these disorders.
Inadequate moisture during early period of fruit growth results in the skin becoming hard and sun burnt. It may crack when it is subjected to increased internal pressure as a result of rapid aril growth following irrigation or rain. Fruit cracking in litchi is also favoured if temperature goes above 38`C and relative humidity less than 60%.
Although effective control measures have not been recommended, frequent and adequate irrigation to bearing trees during fruit growth and development period is most useful.
Growth regulators NAA ( 20mg/ liter of water), GA ( 40 mg/ liter of water), 2,4-D (10mg/ liter of water), Spraying with Zinc Sulphate ( 1. 5%) weekly or Calcium Nitrate (1.5%) fortnightly from pea size to harvesting of fruit is an effective method to reduce cracking.
Yield : The yield varies with the cultivar, age, weather, presence of pollinators, and cultural practices. In India, a 5-year-old tree may produce 500 fruits, a 20-year-old tree 4,000 to 5,000 fruits–160 to 330 lbs (72.5-149.6 kg). Exceptional trees have borne 1,000 lbs (455 kg) of fruit per year. One tree in Florida has borne 1,200 lbs (544 kg). In China, there are reports of 1,500 lb crops (680 kg). In South Africa, trees 25 years old have averaged 600 lbs (272 kg) each in good years; and an average yield per acre is approximately 10,000 lbs annually (roughly equivalent to 10,000 kg per hectare).
Processing of lychee is done in different forms. Canning of pulp, aseptic packing and ready to serve lychee juice are common. Dried lychee processing is not in practice. Pulp of lychee is aseptically packed and stored at 2-3°C for preparing lychee juice.
A substantial amount of lychee produced in the country is consumed locally. Lychee, being highly perishable, is available for very short duration. Marketing of fruits is done in different forms. Growers rent their orchards to contractors, who in turn harvest and sell to local markets.
POTENTIAL FOR LYCHEE PRODUCTION DEVELOPMENT
With increased market base, there is an ample opportunity for increasing the area under lychee as prevailing agro-climatic conditions have not been fully exploited. Extended area under different situations could be exploited for extended harvest. Based on the fruiting behaviour, quality development and area under cultivation, the lychee growing districts could be grouped in a manner to take full advantage of climatic variability. However, to increase production and productivity, concerted efforts would be required for technological support and development of infrastructure. CONSTRAINTS IN LYCHEE PRODUCTION DEVELOPMENT
Despite the fact that the lychee is one of the finest fruits and has a growing demand in national and international markets, productivity continues to be low and a gap exists between potential and existing yield. The ratio in yield between the best managed orchards and national productivity ranges between 2 to 4 times at different locations. The probable reasons for low yield are the narrow genetic base of the crop, non-availability of suitable superior cultivars, traditional production systems, poor technological support and incidence of insect pests, coupled with poor post-harvest management. The shortage of genuine planting material coupled with the long juvenile period of lychee are also the constraints. The low female/male flower ratio, premature fruit drop, and fruit cracking due to non scientific water and nutrient management also add to low productivity and production of poor quality fruits.
The lychee tree has luxuriant vegetative growth, which causes problems in harvesting. Thus, canopy management to achieve the required plant architecture is essential. Lack of scientific information on critical stages for flower bud differentiation, and requirements of water and nutrients also significantly reduces the yield. The lychee has a short shelf-life. Practices that can enhance post-harvest life of fruits would be useful to achieve higher productivity.
. The following points need due consideration:
- Lychee has a very narrow genetic base, which needs to be widened through selection of genotypes from the existing population. Target oriented programmes must be launched so that germplasm is conserved and used.
- A systematic approach for the description of cultivars is needed. Thus, a lychee descriptor needs to be developed.
- Faster multiplication techniques for the production of quality planting material need attention.
- There is need to develop propagation technology for faster multiplication of quality plants.
- The development of nutrition management to maintain tree health and encourage successful flowering, fruiting and quality in sustainable manner, requires attention.
- Monitoring of nutrition in lychee through leaf analysis would be an approach for efficient fertilizer use.
- Integrated management of nutrient and water with efficient monitoring mechanisms would improve input use efficiency.
- Through effective recycling of residues coupled with organic manure, it is possible to improve soil health. Thus, there is an immense potential for organic production of lychee through effective management.
- Integrated management of insect pests and diseases is required to improve productivity and reduce the cost of production.
- Infrastructure for post-harvest management requires emphasis to reduce risk.
- The lychee product range has to be widened for effective utilization.
- Cooperation among lychee growing countries for the exchange of information and cultivars is vital. Starting of a network programme on lychee would boost the production and ensure livelihood security of the people.
The major sources for technology, as well as quality planting material are:
Uses : The fruits may be eaten fresh, frozen or dried in the skin and eaten like raisins. Besides an excellent fruit source in a subtropical orchard, lychee is an attractive, slow-growing evergreen tree. Varieties that mature to shorter heights are particularly good as a small shade ornamental tree in yards. Research into the many varieties of lychee presents options for espaliers, container plantings or for growing in conservatories or sunny atriums. Fruit flavors and sizes also differ according to variety.
Drying of Lychees : The best quality and light color of flesh instead of dark-brown is achieved by first blanching in boiling water for 5 minutes, immersing in a solution of 2% potassium metabisulphite for 48 hours, and dipping in citric acid prior to drying.
Dried fruits can be stored in tins at room temperature for about a year with no change in texture or flavor.
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