Nursery Management in Litchi
Authors: Amrendra Kumar, S.D. Pandey, R.K. Patel and Vishal Nat
ICAR- NRC on Litchi, Musahari, Muzaffarpur, Bihar


Introduction:

Litchi is the specialty fruit of Bihar with highest area 42% and production 55% in the country. The litchi fruit is called queen of the fruit because of its highly attractive red pink fruit on the lush evergreen trees. Litchi is a humid subtropical fruit known for its fragrance, juicy and quality aril. Despite the second highest in acreage and production in the world, it has not been exploited fully in many areas of the country. Amongst the number of factors affecting the production and productivity at present level and key factor for future area expansion programme is timely availability of quality planting material of selected variety in sufficient quantity.

Propagation of healthy and genuine planting material is combination of art and science, which needs advanced technique and requires technological knowledge, capital investment to create required infrastructure, recurring cost and inputs to run the nursery. A successful plant propagator (nurseryman or growers) wants to propagate best quality planting materials at a cheaper and economical rate. During the short span of plants in the nursery, every aspect of cultural practices needs to be followed to develop disease free healthy stock. Because the plants are the first and foremost input required for any successful and profitable orchard. Huge investment in respect of wealth and labour on development of litchi orchards will go waste if the planting material is of inferior variety and or quality. The air layered saplings in the nursery also require high care for final establishment. The planting of layers in container with the media should be rich in organic matter content, moisture holding capacity, drainage and should be kept in propagation structures for better plant health. In recent past, few advancement have been made particularly with respect to better propagation techniques, the substrate for nursery plants, the growing environment for plants and over all the understanding for use of genuine and disease free planting material in litchi which is dealt in details.

Quality planting material production

Litchi saplings can be propagated by seed, air-layering grafting and cutting. In China, vegetative method of propagation particularly though air-layering is in practice from the time immemorial and is the most popular and commercial method of propagation till date. Presently the plant propagation period in case of litchi takes about 8-10 months for air-layers and 1-2 years right from sowing of seeds to grafting in case of grafted plants. The varieties or types which has ideal characters and suited to particular conditions needs to be propagated at large scale in litchi to ensure uniform quality fruit production. To enhance the propagation of horticultural crops in general and litchi in particular in order to propagate healthy vigorous planting materials, it requires manipulation of environment and other conditions for propagules.

• Microclimatic conditions (light, water relative humidity, temperature and gases)
• Edaphic factors (propagation medium or soil, mineral nutrition and water)
• Biotic factors- interaction of propagules with other organisms(such as beneficial bacteria, mycorrhizal fungi, pathogens, insect-pests, etc.).

Standards of Mother block

Location of the mother is one of the most important aspects and requires very careful selection. Every nursery should have its own mother block of selected plant variety/ superior clones. The mother block should be nearer to the nursery for raising the quality planting material. The size of the mother block should be as much as it can sustain the business.

Characteristics of mother plants:

1. It should be of known identity (Shahi, China,)

2. It should have production potential

3. It should have commercial acceptance

4. It should be free from pest and diseases.

Nursery structures and their Management:

A number of structures may be necessary for raising a nursery as per the norms to make quality planting material propagation at commercial scale. To begin with, the following structures need to be constructed: corrhizal fungi, pathogens, insect-pests, etc.).

1. Working platform or work-shed
2. Net house/ mist house
3. Store-cum-office
4. Fencing
5. Water source
6. Substrate/ medium

Potting mixtures/ media for growing air layers

Detached air-layers of litchi are directly planted in the field but the tradition changes and started planting in container having blended mixtures. Now container mixtures become important for planting the propagules in them as an alternative for field planting to growers. To buy a pre blended potting mixtures is costly affairs for the nursery man so it would be proper to prepare media from locally available substrates as per the regional availability.

A good nurseryman can prepare their own substrate mixtures by adding different proportions of the basic materials in bulk with loam soil, and make their own enriched potting mixtures. You can buy some of these materials from markets and after through mixing prepare the potting media at nursery site and you will save some money in doing this. Most of potting media involve variations on 4 primary components viz. Coarse Materials; Water-Retaining Materials; Bulk Nutritional Materials and Concentrated Organic Soil Amendments

Characteristics of ideal potting media: Various substrates and mixtures of different minerals are used for growing saplings and for good results the potting media should have following characteristics-

a) The medium must be sufficiently firm and hard to hold the air-layers with minimum exchange in volume when wet or dry. Excessive shrinkage after drying and expansion after wetting are undesirable as they damage of root tip of air layers.

b) It must be easy to wet and retain sufficient moisture to reduce frequent watering.

c) The medium should be stable and fully decomposable (CN ratio>20:1) to prevent N immobilization with minimum shrinkage.

d) The medium should be porous to drain excess water and permit adequate aeration (oxygen) to the roots and should have high CEC (cation exchange capacity) for retention of nutrients for longer period during propagation.

e) It should be free from pest, diseases, weeds and nematodes.

f) It should be locally available, cheaper and economical.

In the propagation of horticultural crops like litchi potting media used should consist of mixture of organic and inorganic components in different proportion and to be complementary to each other.

Steps for making potting mixtures:

While preparing the potting mixture, the media should be sieved for uniformity to remove large particles. The material should be light moistened. The various substrates/ingredients may be arranged in layers in a pile and turned with shovel/ spade. Power operated mixture machine may be also be used in preparation of large scale potting medium required for planting operations. The mixtures should be preferably prepared a day before prior to use because during this period the media is equally moistened throughout mixtures.

Enriched potting mixture for litchi propagules:

Till date there is no such single ideal mixtures are available for litchi air-layers/ propagules. Hence appropriate mixtures for location and plant specific keeping in view propagation method is identified which is locally available and comparatively cheaper and economical.

It can be prepared by mixing peat, vermiculite vermin-compost, soil and other organic/ inorganic substrate. For propagating litchi air-layers a substrate mixture having 2 part RBS (river bed soil), 1 part VC (Vermi-compost), 1part coconut pit and small proportion of vermiculite (50g per kg of mixture of each substrate) has been standardized at National Research Centre for Litchi Muzaffarpur.

Containers for growing saplings:

Different types of containers for growing young litchi plants have been developed with a view to have easy survival and transport. For propagating litchi plants polyethylene bags, pots of different sizes, shape and colour is being used. They are non porous, reusable, light weight and take little storage space. The containers are made of plastic, fiber and paper pots. For commercial propagation of litchi air-layers poly bags of 25x10x13 cm size are more suitable, because of its light weight and reusable nature and cheaper costs. A container having 3.5-4.0 kg of potting mixtures of soil, sand, FYM is considered ideal for use. The containers are usually of black colour, but some are black inside and light coloured out side. The lighter colour reflects heat and lowers the root temperature. Major drawback of these poly-bags are they do not prohibit root spiraling or allow air pruning.

Root trainer:

Root trainers of different volumes and geometrical arrangement are available in market. These can be used for raising seedling rootstock of litchi as well as for initial establishment of air-layers in the nursery. The root trainer of 500 ml capacity arranged in combined tray having 12 conical holes has been found better for litchi. These root trainers fitted on the iron stand of appropriate width of 30-45 cm height while planting the saplings in the root trainers, the medium should be light with better water holding capacity and nutrients to support the plants. The root trainers are designed in such a manner that the developing roots are guided towards the base of the cone. If they are fitted on the stand, the root coming out of the root trainer in the bottom are self pruned by the air pressure which facilitate the development of secondary and tertiary root fabrics around the entire medium in side the root trainers. After one or two flush, complete web of root developed in the saplings and the plant can be shifted to the other container having larger size and amount of substrates. With the help of root trainers more number of plants can be accommodate in mix chamber/ green house.

Aftercare of nursery plants:

An appropriate and timely feeding, watering and plant health management programme is required for vigorous and healthy growth of the litchi saplings in the nursery.

Nutrient Management :

Among the nutrients, nitrogen has the most impact on the amount of vegetative shoot growth, Phosphorus is very important for formation of secondary and tertiary root system, plant energy reactions and photosynthesis. Potassium is important for plant water relation and enhanced drought resistance. It has been observed that for healthy and vigorous growth of litchi saplings throughout the period in nursery there is need to maintain 10-15 ppm of phosphorus in the potting media. As phosphorus is leached very rapidly so in order to maintain the nutrient level controlled release fertilizers is to be used or in small quantity soluble phosphorous to be applied periodically.

Water management:

To maintain the turgidity of the plant and optimum moisture level in the growing medium, the plants in the nursery should be watered regularly with the automatic sprinkling system or manually during the dry period. The excess water which may cause the rooting of root system in the litchi plants should be avoided. As practice the plant should be irrigated twice during winter season where as during summer 3-4 time light irrigation would be required in the nursery of litchi.

Plant Health:

A number of pests and disease may harm the growing plants under the nursery. There are many foliar disease pest however sometimes soil borne disease/nematode and termites may affect the nursery plants.

Management of Insect pest of litchi plants

Leaf miner

• Infestation occurs at new flush emergence and larvae damage the tender leaves

• Timely removal of affected twigs/ leaves

• Two sprays of Imidachlorpid (0.5ml/l water) or Neem based pesticides (5ml/l water) at 7-10 days interval during new flush significantly reduced the damage

Litchi leaf roller (Platypeplus aprobola Meyer)

• The incidence takes place from July to February in grown up tree and during new flush emergence in the newly planted litchi.
• Excessive growth can be avoided.
• Litchi leaf roller successfully can be managed by spraying Diemethoate (0.03%)/ Imidachlorpid (0.5ml/l water) twice at 7 days interval when there is high population.

Litchi bug:

• The nymphs and adults can be seen on fruits during April-May.
• Avoid crowding in the orchards
• Nymphs and adults can be collected and destroyed
• In case of severe attack a single spray of Sevin 0.02% takes care of the litchi bug.

Leaf cutting weevil: (Myllocerus discolor Boh. and M. undecimpustulstus Faust.)

• Population of the weevil was highest during November-February.
• On noticing the infestation shakes the plants.
• Collect the fallen weevil and destroy.
• In case of severe infestation apply Diemethoate (0.03%) twice at 7-10 days interval.

Litchi mite

• Incidence of mite take place during Oct.-Nov. and March- April
• The affected plant parts shown symptom of velvety growth on lower surface/ twigs/ panicles/ fruits.
• Removal of affected parts from plants and burning
• The mite population can be suppressed by application of miticide like Omite or Kernel S (3.5ml/ l water) twice at 7-10 days interval.

Disease incidence observed in nursery

Anthracnose disease (Botryodiplodia theobromae) : Visual; appearance of brown to black irregular spots on few leaves.

Leaf spot disease (Pestalotia pauciseta) Visual; appearance of circular brown to black irregular spot on leaf.

Dieback disease (Diplodia spp) Visual; appearance of brown lesion on shoots, premature leaf drop and drying from the top.


Nutrient deficiency observed in nursery

Detection and Diagnosis

• N - Yellowing of leaves and stunted growth
• K - Leaf tip drying extending to leaf margin
• Cu - Reverse cup shaped, narrow elongated, abnormal leathery leaf growth appearance on young leaves.
• Zn - Leaf vain clearance and drying of leaf from margins all along.


Standards of planting materials:

To ensure the genuine planting material and avoid spurious/sub standard planting material, certain standards for establishing litchi nursery has been prescribed below.

Information regarding parent material

Age of the elite mother tree - > 8 years and above, should be a stable yielder and free from pest and diseases.
Type of planting material used for propagation - Vegetative shoot
Method of propagation - Vegetative (air layering)


      i) Age of the shoot - > 8-10 months old.

      ii) Diameter of the shoot - 1.0-1.25 cm

      iii) Length of the shoot - 25-35 cm

      iv) Age of the rooted air-layers - 2.0-2.5 months (date of air- layering and planting in the nursery)

      v) Height of the air layered plants - 40-50cm (minimum)

      vi) Diameter of the air layered plants - 1.5-2 cm

      vii) Growth of the plants - Vigorous and healthy (5-7 months old)

      viii) Root system - Well developed

      ix) Condition of the earth ball - Intact and moist

      x) Varietal purity - Should be maintained

Labeling:

While supplying the plants the details of the crop and plants should be printed on label and it is the duty of the nursery to provide detailed information on the tag to the customer. The tag should contain following information.

Contents of label

Crop : Litchi
Variety : Shahi/ China/.........
Type : Air layer
Age : one year
Planting time : June- July on onset of monsoon
Bearing : Regular
Exp. Yield : 2-2.5 q/ plant (20 yr)

Troubleshooting in pot or propagated plants

PROBLEM: Potting mix shrinks away from sides of pot, water rushes through gap and out the bottom of the pot, instead of sinking into soil.

This problem happens most frequently in earthen terra cotta, ceramic, and single-walled plastic pots, where the sides heat up during the day, but it can happen in any type of container, especially with faulty or old potting mixes or root bound plants. It's made worse by haphazard watering, so making sure the plant gets regular light water and hoeing of the pot before watering is part of the solution.

Stop gap or crack formation in pot/container: Use a hand cultivator to go around the inside edge of the pot, where the potting soil has pulled away from the pot. Claw to break up the crust. Push the loose material into the gap, and water. Watered the plant more frequently to prevent the recurring problem of moisture loss.

Better substrate mixture: Riverbed soil, Vermi-compost and coconut pith (2:1:1) with 50g Vermiculite and coconut coir each per kg of mixture is a great band-aid for container gardening problems. Rehydrate the pot with water and spread a 1" layer of vermi-compost over the surface of the pot. Press some down into the gap between the pot and the soil, but don't pack it tightly. Go around the inside edge of the pot with a hand cultivator, clawing the moistened coir down into the surface crust and water thoroughly.

The solids as non-edible oilcakes can be mixed into potting mixes for plants, or added to containers as a top dressing. Top Dressing involves applying small amounts of organic soil amendments to the soil surface, cultivating them lightly into the soil, mulching, and watering.

Variation: Mix some neem/ karanj oil cakes and grounds into the container mixtures when the saplings become 2 months old as it is contain small amount of NPK with insecticidal properties and a slight acidifying effect on the soil.




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