LITCHI CULTIVATION: CONSTRAINTS & SOLUTIONS

Production:-

(a)     Specific Climate Requirement: Litchi flourishes well in the sub-tropical humid climate, free from heavy frost during winter and hot desiccating winds in summer. A temperature range of 4-7 degree Celsius before flowering is essential for good flower initiation. This restricts the Litchi cultivation in humid sub-tropical climate.

(b)     Specific Soil requirement: Litchi prefers deep and well drained loamy soils rich in organic matter. Calcareous soil (Bhatt) with a pH range between 7.5 to 8.5 is well suited for Litchi cultivation. Proper “Mycorrhizal” build up in the soil is helpful for better establishment and productivity.

(c)    Narrow Genetic Base: Litchi is an introduced crop in India and is commonly propagated through air layering in the country. These two factors are responsible for narrow genetic base. Hardly 10 varieties are available in different regions. An ideal Litchi variety should have following characteristics:

 

i.       Bearing :- Short statured, precocious and prolific bearing;

ii.      Foliage :- Dense foliage, so that fruits are not exposed to sun strokes;

iii.     Fruits :- Large size fruits, attractive red flush, good shelf life, retentive flavor, high pulp and low seed content.

Varieties like Rose Scented, Calcuttia, Dehra Rose, Late Seedless etc. are well adapted to western part and China and Shahi to eastern part of the country.

Efforts should be made for breaking the barrier of narrow genetic base. This can be achieved either by introducing more varieties from China, Philippines, Thailand, South Africa, Hawaii or by creating variability in the available sources (seed propagation, induction of Polyploidy, mutation and hybridization) through various breeding techniques.

(d)    Non Availability of Elite Planting Material: Non-availability of planting material is one of the major constraints in the spreading area of Litchi cultivation. It is advisable to encourage establishment of model Litchi nursery at State Agricultural/ Horticultural Universities, Research Stations and also with private entrepreneurs. It is also advisable to encourage the establishment of separate “Mother Block” of elite clones obtained from known sources. After the initial establishment for 3 – 4 years, vigorous shoots with better root ability for air layering. Rooted shoots should be shifted in poly bags/ Root Trainer before selling for planting for better establishment.

 

(e)   Poor Initial Establishment: Poor initial establishment and slow growth in early years of plantation is the main hindrance in Litchi cultivation. In comparatively warmer, on transplanting in field, general mortality of the plants is very heavy. The young trees suddenly shed all their leaves in hot weather and these cannot be saved later on. There is a common practice of transplanting the rooted air layered plants under dense shade for initial establishment. These plants are delicate and hence they die when exposed directly to scorching sun. It is advisable that instead of dense shade, air layered plants should be transplanted in partial shade or polybags or in Root trainers which ensure almost cent percent establishment.

 

(f)    Long Gestation Period: Air- layered Litchi plants start bearing after 5- 6 years of plantation and attains commercial bearing after 10- 12 years onwards. Other methods of propagation viz. grafting, budding, have been tried experimentally in China, Hawai and Philippines. There is need to select out rootstock/ scion combination through which plant vigour and gestation period could be reduced. Role of growth regulators viz. Paclobutrazol and other chemicals also need to be evaluated. In order to ensure some income, efforts need to be initiated to standardized inter cultivation with high value inter and filler crops.

Protection:-

(a)  Wind Breaks: Hot and desiccating winds in summer and cold winds in winter adversely affected the growth of Litchi. So, for proper establishment of Litchi plantation, a suitable wind break/ shelter belt should be planted around the orchard boundary. A thick row of tall growing trees with dense foliage viz. seedling Jamun, Mango, Jack Fruit, Teak, alternating with low headed trees such as mulberry, subabool etc. should be planted two to three years before establishment of Litchi orchard. This will improve the microclimate and will be helpful in minimising the incidence of fruit cracking and fruit growth.

 

(b)   Mulching: Maintenance of optimum moisture regime is one of the key factors for successful Litchi cultivation. Mulching may be an ideal tool for maintaining optimum soil moisture. The use of mulch will encourage the development of better root systems of young Litchi plants at a much faster rate than in case of plants growing in bare soil.

 

(c)   Physiological Disorders: Sun burn and cracking of fruits are the serious problems. Cracking of fruit is promoted by variation in temperature and humidity, prolonged drought and inadequate/ fluctuating in soil moisture during the early period of fruit growth, high Nitrogen, deficiency of B and Ca and hormonal imbalance. Varietal reaction to this disorder is also there. Few varieties viz. Deshi, Shahi, Rose Scented are more susceptible than China, Calcuttia and Late Bedana. To check this problem, it is advisable to maintain 40-50 percent available soil moisture in root zone during the fruit development Mulching round the trees, maintenance of thick wind break, frequent spray of water and Auxin have also been recommended to be helpful in reducing the problem. Spray NAA (100 ppm) and GA₃ (100-120 ppm) during fruit growth period. Spray borax (0.8%) is equally useful in checking the fruit cracking.

 

(d)   Micro Nutrient Deficiency: Zinc and Boron deficiencies have been recorded in old Litchi plantation. Zinc deficiency is characterized by general bronzing of the Litchi leaves. The leaflets become small, pointed and inter-nodes remain short. Zinc deficiencies may be corrected by spraying of 4 Kg hydrated lime in 500 litres of water and the trees should be sprayed in spring as soon as they put out new leaves. Fruit cracking and necrosis of aril is because of boron deficiency. Incorporation of 2 Kg boron will take care of boron deficiency.

 

(e)    Pest and Disease: No Serious disease on Litchi has been reported, but insect pests cause considerable loss. Most serious pest include mite (Acaria Litchi), Bark eating caterpillar (Inderbela tetraonis), shoot borer (Chiumentia transversa).

             i. Mite: - Nymphs and adult of Acaria mite suck the sap of leaf lamina, which become thickened, leathery, forming velvety structure and curl up. New flush is very vulnerable to the infestation. Clean cultivation (i.e. remove the infested leaves and destroy them), incorporation of neem cakes @ 5- 6 Kg per tree, destruction of infested leaves and twigs and spraying of miticides are helpful in minimizing the incidence. For Mite control, Phosphamidon (0.05%) or Dicofol 18.5% EC (0.05%) i.e. @ 1080- 1020 ml in 400- 1000 litre of water per acre and observe the waiting period of 15- 20 days. It can be sprayed during February, March and May. One spray can be done in September- October. Spray of wettable sulphur @ 100 gm in 20 litre of water in May- June after harvest of fruits and again in winter (December- January), when trees are dormant and mites are torpid with cold.

                 ii. Shoot borer: - Shoot borer can be controlled by spraying Dimethoate 30 EC @ 1 ml per litre of water at 20 days interval during August month.

               iii. Bark eating caterpillar: - Clean the ribbon made by caterpillars and stir with the sharp metal wire. Then put the fumigants, such as petrol/ formalin/ carbon disulphide dipped cotton into the holes and plug with soil paste/ mud.

              iv.  Fruit & Nut Borer: - A severe attack of insect larvae (Lepidoptera) between fruit peduncle and the seed has been noticed. As a result, the pulp turns brown near seed, the taste is badly affected and there are insect dejecta. In some cases, almost 90 percent fruits were observed to be infested. This appears to be a serious problem, which requires immediate attention. Collect and destroy the infested fruits. Rake the orchard soil to destroy the pupae during March, but before April to expose the pupae to high temperature and natural enemies. Spray of Quinlphos (0.05%) at 15 days interval starting from fruit formation stage is effective.

Literature consulted:- Article written by R.K. Pathak in Hortivision-2020, published by Department of Horticulture, Himachal Pradesh, Shimla 171002 and Fruit Production: Problem and solutions book by R.R. Sharma.