The introduction of Litchi:
Litchi (Litchi chinensis Sonn) is an important subtropical fruit crop of the country. It is known as the queen of the fruit due to its attractive deep pink/red colors and fragrant aril. It has high nutritive value and suitable for a geotropic weak person.
Litchi is an important commercial fruit crop in India due to its high demand in the season and export potentiality. Cultivation of litchi is widely spread in eastern India covering approx. 100 km width from foothills of Himalaya from Bengal to Punjab which provides livelihood opportunities to millions of people in the region. In India, the bulk of the litchi growing area lies in Bihar; other areas are sub-mountain tracts of Uttar Pradesh, West Bengal, Punjab, Assam, Tripura, and Odisha.
Scientific name-Litchi Chinensis.
Area and Production Required for Litchi:
In India, about 73000 ha area is under litchi plantation which produces approximately 5,00,000 MT fruits every year. Although synonymity exists more than 20 cultivars have been listed under cultivation. The important varieties are Shahi, China, Bedana, Rose Scented, Bombai, Purbi, Saharanpur, Muzaffarpur, and Kasba. Bihar is the premier state in litchi production and marketing. Litchi is being cultivated in the vast area of Bihar (30, 500 ha) with an annual production of about 2, 50,000 MT of fruits having a productivity of around 7-8 tons/ha. It accounts for nearly 52 percent of litchi production from 50 percent of the total area under litchi at the country level.
The area and production of litchi are increasing, but at a very slow pace, however, the productivity is declining due to the plantation of new orchards in recent years and reduction in realizable yield in old senile orchards. The harvesting of litchi fruits starts from last week of April in Tripura to end of July in Himachal Pradesh and foothills of Uttarakhand. In Bihar, the harvesting period lies between 2nd week of May to 3rd week of June for different cultivars like Early Bedana, Shahi, Mandraji, China, Purbi, Rose Scented, Longia, etc
Soil required for Litchi:
Litchi can grow in a variety of soil provided they be well drained. The ideal soil for litchi cultivation is deep well- drained loam soil rich in organic matter. The water table should be at least 1.25 m deep. It cannot stand water-logging for long. Litchi prefers slightly acidic to neutral soil. The trees grow best in a pH range of 6.0 to 6.5. The roots of litchi trees are found to have a symbiotic association with mycorrhizal fungi which improves the nutrient uptake and availability in root zone. Before planting, it is worthwhile to inoculate the soil in pit by mixing some soil collected from the root zone of litchi orchards.
Climate requirement for Litchi:
Litchi prefers moist subtropical climate. Winter frost and dry heat in summer considerably damage the growth of the plants. Although it can grow up to an altitude of 800 m above the sea level, the best growth and yield was, however, found at lower elevations. Seasonal variation in temperature is necessary for proper fruiting. The temperature should not go beyond 40.50 C in summer and below the freezing point in winter. A good rain or adequate supply of irrigation water is essential for litchi cultivation. A constant rainfall at the time of flowering, however, interferes with pollination.
Improved Varieties of Litchi:
In India, about 50 cultivars are under cultivation. However, Shahi, China, and Purbi are ruling commercial varieties for North Bihar and eastern Uttar Pradesh. Rose Scented for Uttaranchal and adjoining area, Shahi, Ajhauli, China, Swarna Roopa and Purbi for Jharkhand and Bombai, Bedana and Rose Scented in Eastern parts of West Bengal are other commercial varieties of importance. Few varieties (Table 3) have been found promising for high yield with quality fruits and have been well adopted in the region. The description of few important varieties suitable for growing in different parts of the country has been given below.
Shahi
This is the most popular cultivar of Noth Bihar, Jharkhand, Uttaranchal and Uttar Pradesh. The fruits have a distinct rose aroma and hence called as Rose Scented. It is known as “Shahi” in Uttaranchal and “Muzaffarpur” in Western Uttar Pradesh. This is an early season maturing cultivar ripens during the second week of May to the first week of June at various locations. It matures 12-15 May in Jharkhand,25th May in North Bihar and by the end of May in Tarai region of Uttaranchal.
Trees are very vigorous (7.6 m height and 8.2m canopy spread), and high yielder (90-100 kg/tree) but mature fruits are prone to cracking. Fruits are medium to large (3.2 cm length and 3.1 cm diameter), medium in weight (20.49 g/fruit), globules-heart or obtuse in shape having rose madder and fuchsia purple background with red tubercles at ripening. Pulp grayish-white, soft moderately juicy (54.8%) and sweet with 200 Brix TSS, 12.79% total sugar and 0.33% total acidity. Seeds are small (1.89 cm length,1.32 cm diameter and 2.07 g weight), smooth, shining round-ovate in shape and blackish-chocolate in color. Rind: pulp: seed ratio by weight is 12.22: 75.93:11.85. The fruits are known for excellent aroma and quality aril.
Early Bedana
It is also known as Early Seedless because of its early ripening and small seeds. The cultivar is very much popular in Uttar Pradesh and Punjab. Trees are medium, attaining an average height of 5.0 m and spread of 6.2 m. It is a medium yielder cultivar (50-60 kg/tree) but bears fruits regularly. Fruits are medium in size (3.2×3.0 cm) and weight (16.33g) having oval or heart shape, rough surface with uranium green skin covered with carmine red tubercles at maturity. Aril is creamy white, soft, juicy (69.0%) and sweet containing 19.8% TSS, 13.6% total sugar and 0.54% titrable acidity. Seed is very small, shrunken, glamorous, dirty chocolate in color with an average weight of 0.82g. The rind: pulp: seed ratio by weight is 13.06: 83.19:3.75. The overall fruit quality of the cultivar is good.
Late Bedana
This cultivar is also known as Late Seedless. Late bedana is a late maturing variety which usually ripens in the third week of June in Uttaranchal and end of May in Jharkhand. The trees are vigorous having an average height of 5.5 m and spread of 7.0m. It is a high yielder cultivar giving an annual yield of 80-100 kg/ tree.
Although the fruit size is medium (3.2x 2.9 cm) but average weight is 25.0 g. The fruits are conical in shape with vermilion to carmine in color having dark blackish brown tubercles at maturity. The pulp is creamy white, soft, juicy (65.4%), sweet having 20.0% TSS, 13.8% total sugar and 0.44% acidity. Seeds are very small (1.8×0.9 cm in size and 0.85 g in weight), shrunken, glamorous, chocolate in color having a fusiform shape similar to the canine of dog. The rind: pulp: seed ratio (by weight) of late seedless is 14.76:81.89:3.35. Overall quality of fruits is very good.
Ajhauli
This is another early maturing variety becomes ready for harvest by 15-18 May and yields about 80-100 kg from a sixteen-year-old tree. The tree is vigorous in growth. It bears red fruits with an average weight of 17.3 g and contains 59.3 mg/100 vitamin C. The TSS of the cultivar is 20% with 0.4% acidity and 12.37 g/100 g sugar. The full grown up tree yields 70-95 kg fruits every year.
China
This in one of the best cultivar of litchi for North India. It is tolerant to hot waves and fluctuations in soil moisture which escapes to fruit cracking. It is also known by the names of Calcutta in West Bengal.
This is a medium-late season cultivar, and fruits ripen during the end of May in West Bengal, the first week of June in Jharkhand and during the second week of June in North Bihar. Trees of cultivar China are dwarf (4.0 m height, and 6.0m spread) and high yielder (80-100 kg/tree) but prone to alternate bearing. It bears fruits in a cluster of 12-18. The plants bear less fruit in southern direction.
Fruits are large (3.86 cm length and 3.26cm diameter), medium in weight (22.0g/fruit), oblong in shape and tyrant rose in color with dark tubercles at maturity. Aril is creamy-white, soft, Juicy, sweet having 18.17% TSS, 11.0% total sugar and 0.430 Brix titrable acidity. Seeds are glaucous, dark chocolate in color, oblong to concave or Plano-convex in shape, medium in size (2.9 cm length and 1.5 cm diameter average in weight (3.49 g/seed). The ratio of rind: pulp: seed by weight is 16.42: 69.22:14.36.
Bombaiya
This is an outstanding cultivar of West Bengal. It is a vigorous cultivar attaining a height of 6-7 m and spread 7-8 m. The variety matures early (first to the second week of May) and gives 80-90 kg yield per tree. Fruits are large (3.5 cm long and 3.2 cm diameter), obliquely heart shaped, weighing 15-20 g. The color of ripe fruit is attractive carmine red with uranium green skin background.This cultivar also has a small, tiny under developed fruit attached to the fruit stalk of each fully developed fruit. The pulp is grayish-white, soft, juicy, sweet containing 170 Brix TSS, 11.0% total sugar and 0.45% acidity. The elongated, smooth and shining seed of litchi cultivar Bombaiya light chocolate color is 2.3 cm long with 1.6 cm diameter and weighs 3.4g. The ratio of rind: pulp: seed in this variety is 12.1: 70.1:16.8.
Dehra Rose
This is an outstanding cultivar of Uttar Pradesh, Uttaranchal, and Punjab. Fruits start ripening by the third week of June. Medium vigorous trees (5 m height and 7m spread) produce medium to high yield (80-90kg/ tree). Fruits are medium to large measuring 3.7 cm length, 3.5cm diameter, 15.2 g weight having oblique-heart to a conical shape. Carmine red colored fruits of Dehra Rose look very attractive at ripening. The pulp of this cultivar is grayish-white, soft, moderately juicy (61.9%), with 17% TSS,10.4% sugar and 0.44% acidity. Seeds remain small (2.4cm length, 1.4 cm diameter, and 2.4 g weight), shrunken, mostly oblong in shape and dark chocolate in color. The rind: pulp: seed ratio is 18.4: 64.4: 17.2. The primary defect of the cultivar lies in its susceptibility to sunburn and cracking.
Plant Propagation and Nursery Management for Litchi:
Litchi is commercially propagated through vegetative method. The plants raised from seed have slow growth, long juvenile period (8-12 years) and do not produce true-to-type fruit. Therefore it is recommended that only vegetatively propagated genuine planting material should be used for commercial production. The methods for plant propagation are being described:
Sexual propagation:
Seeds are mainly used to raise rootstocks for grafting. Litchi seeds have short viability period. If these are exposed to air in the shade under normal humidity conditions, they start shriveling within 24 hours and in five days become inviable. For raising plants from seed, only mature and bold seeds should be selected. Small seeds in which embryo have aborted never be used for raising rootstocks.
After being separated from the fruits, the seeds are cleaned and sown horizontally to a depth of to 2.5 cm in a well-drained sowing medium in a partially shady well-irrigated location. The planting medium may be a mixture of sand, soil, and compost which can provide sufficient food and aeration to the newly germinated seeds. Incorporation of soil from old plantations of litchi has been found to encourage germination. Seed germination takes place within three days under normal conditions. Seeds can also be sown in the trays and transplanted into individual bags after attaining a height of 10 to 15 cm for the development of healthy root stock. In this case, to facilitate transplanting, the seeds should be sown at a distance of double to the length of the seed. Seeds are extremely slow to grow and therefore nourished properly so that it can be used as rootstock for grafting.
Vegetative propagation:
Vegetatively propagated plants are true to type in nature and start early bearing in the commercial litchi orchard. The different methods of vegetative propagation in litchi are given below.
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Air layering
Among the various methods of vegetative propagation, air-layering is commercially one. Air layering can successfully be done just after fruit harvest (June-July) when plants are in the active phase of growth. The best season for air layering is monsoon season. In mother trees maintained exclusively for propagation purposes, the layering can also be done during the spring with optimum water and nutrient management. Usually, Sphagnum moss is used as rooting media.
For the preparation of air layers, healthy terminal branch receiving good sun shine with a thickness of about 1.2-1.5 cm is selected. Better the branch used for layering, better the root system obtained. The branches must be selected on the periphery of the tree so that they can easily be worked on. The newly flowered/fruited shoot which has exhausted its food material produces poor roots, thus should not be selected for air layering. On a selected branch, 2.5 cm ring of bark is removed about 45-60 cm below the tip of
On a selected branch, 2.5 cm ring of bark is removed about 45-60 cm below the tip of the shoot. The cambium layer is rubbed off, and a woody portion is exposed properly. For early and proper rooting pasting of 1000ppm, IBA may be done immediately. Applying 5000 ppm IBA in lanolin paste at the upper end of the ring also improves the root formation in air layers. A layer of moist sphagnum moss is placed and wrapped with a piece (20x25cm) of 400 gauge polythene sheet and tied properly on both end to ensure supply of proper moisture and facilitates the development of roots.
In the place of sphagnum moss, a decomposed mixture containing pond silt 40 kg, FYM 40 kg, well rotten jute bag or leaf mould 10kg, castor/ karanji/ neem cake 2kg, urea 200g, 200g SSP/ bone meal and 100g Chloropyriphos dust can used as ideal media for root initiation, development and better survival of the plants.
The above mixture is heaped after proper mixing and covered with black/white UV stabilized polythene for 45 to 60 days under the open sun.
The soil lump is prepared by adding sufficient quantity of water at the time of air layering, and a ball of approximately 200g is prepared for each air layers. The ball of rooting media is placed over the ringed portion covering about 2 cm from the upper end of the ring. After about 50-60 days the adequate root system is developed from the upper end of the ring which is visible through the polyethylene film. The layer is removed by giving sharp cut about 5 cm below the lower end of the ring. The air layers should only be removed when 6 to 8 roots can be seen through the polyethylene which is changing from white to creamy brown.
Special care must be taken to avoid damaging the young root system while transplanting the layers. The detached layers are planted in partial shade, and at the time of planting, excess vegetative growth should be removed to maintain a balance between the top and newly developed root system. The young plants must be planted in individual bags (15x15x25 cm) filled with a good mixture of soil, vermicompost, sand and Vermiculite. Two or three vegetative flushes must appear before the plants hardened off in the open air before final planting. Planting of detached air layers in the root trainer of 350 ml cup size facilitates the better root development in the litchi air layers.
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Wedge grafting
This is a detached method of grafting in which grafting operation is performed on about one-year-old seedling. The 3-6-month-old scion stick is taken from the shoots. The best time for grafting is rainy season and spring season. For rainy season grafts, short (3-4 buds), round scions of green but completely mature wood (just before the opening of new shoots), are preferred while for spring graft, hard and semi-hardwood is selected. It is advisable to take healthy and disease free scion sticks. However, for better success treatment of scion sticks with 0.1% Benomyl is recommended.
Under favorable temperature conditions, the sprouting of buds takes place within 2-3 weeks of grafting. The new plants having 50-100 cm height may be planted after sufficient hardening within a year of grafting. For better success, raise the rootstock in polythene bags of 4-5 kg capacity, and plant successful grafts into bigger sized bags.
Litchi Plant Nursery Management:
A high rate of mortality in the newly planted litchi layers in nursery beds/ polythene bags is quite often which is attributed to several post planting factors in the nursery. The details of the nursery management operations to be carried out are as follows.
Preparation of potting mixture:
The mix of rever bed soil, FYM or vermi compost (2:1) with vermiculite/perlite 50g/kg mixture should be prepared in the proportion. Preferably the soil from old litchi orchard should be incorporated in the mixture to improve the mycorrhizal colonization in the root which helps in the development of better root system and plant growth. The areas having the infestation of termites in the nursery, use of anti termite, pesticides and Karanj /neem cake in the potting mixture or fumigating the potting mix with appropriate soil fumigant is recommended. The addition of phosphorus in the potting mix has given encouraging result. Therefore, single super phosphate/ bone meal @10g/bag should be added while planting the air layers.
After care of the newly planted air layers in the nursery:
The newly planted air layers should be given the utmost care in the initial period of establishment. Maintenance of optimum temperature and humidity in the mist chamber and proper irrigation under shade after shifting should be ensured for better success. Control of foliage pest and diseases through appropriate pesticide/ fungicide should be done. New flushes of litchi layers encounter the attack of litchi mite, leaf cutting weevil, shoot borer and leafminer pests.
Litchi mite can be managed by spraying 1.25ml / liter Phosphamidon or Kelthane thrice whereas for other pests two to three sprays of Nuvan (1.25ml/liter) should be made after noticing the pest. Litchi layers do not get infected by foliar diseases. However, soil borne pathogens do to the newly developing secondary and tertiary root system of the layers. Sometimes, excessive water stagnation in the bag/bed leads to rotting of collar region leading to mortality of the plants. Which can be managed by drenching of soil with Bavistin (2g/ltr) and avoid excessive moisture in the root zone.
The main reason for the high mortality in the nursery plants has reduced the formation of secondary roots. While planting two months old air layers in the bed/bag, the formation of a secondary root is restricted. This can be improved by planting the layers in root trainers (350ml size) for initial two months under mist chamber (Temp30+20C and RH 90% ). While planting in root trainers, a mixture containing two-part FYM, one part sand a small amount of SSP (1 tea spoon/cup) and a small amount of soil (20g/cup) from old litchi orchard should be used for filling the containers.
A quick dip of air layer’s ball in IBA solution (1000ppm) help increased secondary root formation. The root trainers should be kept at the height of 1.5-2.0 feet from the ground level on the iron frame so that air can blow beneath the root trainer. During the process, the primary roots growing through the root trainers are naturally pruned. Natural air pruning of the roots in root trainers helps in the formation of secondary and tertiary roots in the root trainers. After two months, when the first flush gets matured, the individual saplings should be transferred to polythene bags (25x15x15cm size and 400 gauge thickness) containing the standard mixture. Along with SSP (10g/bag) and kept under partial shade. Regular maintenance of the plants should be done to facilitate better establishment and growth after shifting from root trainer.
Planting and Orchard Establishment:
Litchi plant starts bearing after 5-6 years and attains commercial production stage after 10-12 years. The performance of orchard depends upon the proper layout, pit preparation, planting system, care and maintenance of young and bearing trees. Scientific management of the orchard including water and nutrient management, stature and canopy management of plants, pruning, treatment of shoots for flowering and fruiting and use of plant growth regulators to optimize the quality production. The suitability of a cultivar is the factor of the ecological condition of the site, availability of genuine planting material, and consumers and market preference.
Selection of site for Litchi:
Selection of the location for litchi orchard is vital for optimum production owing to its specific climatic requirement. Frost free climate with mild cold (8-140C minimum temperature) and the dry period before flowering during autumn-winter, moderate temperature and humidity during flowering, fruit setting and fruit maturity and absence of high-speed wind during fruit development and maturity are considered ideal for litchi orchards. Litchi plants are also specific to their soil requirement. Therefore, the site should have deep, mild calcareous, well-drained soils with high organic matter.
However, litchi can be cultivated in almost all kind of soil, starting form sandy to clay loam with good drainage and rich in organic matter. Well drained deep sandy loam soil having high moisture holding capacity, rich in organic matter and calcium content has been found ideal for litchi cultivation. The fertile soil with good moisture holding capacity facilitates better growth and fruiting. The well-drained soil of north Bihar rich in calcium content have been observed to be suitable for better growth and quality fruits. The rolling uplands of Chotanagapur and organic matter rich Tarai regions of Uttaranchal have also been found to be highly appropriate for the proper crop of litchi. It has been observed that mild acid soil is ideal for
The rolling uplands of Chotanagapur and organic matter rich Tarai regions of Uttaranchal have also been found to be highly suitable for the good crop of litchi. It has been observed that mild acid soil is ideal for an association of mycorrhiza in the litchi rhizosphere. The soil having pH from 6.0 to 8.5 with the abundance of soil moisture is suitable for proper growth and fruiting in litchi. Soils of poor physical condition, lacking in available nutrients can be improved for litchi cultivation by adding sufficient quantity of rotten FYM/ compost and green manuring. Apart from above ecological features, adequate infra structure facilities like cold storage, transport, electricity, etc. must be available near the production sites.
Land Preparation and Layout for Litchi:
Before layout, the land should be cleared of bushes, weedy vegetation and ploughed deeply. Further the surface to be leveled with a mild slope in the opposite direction of the water source. To improve the fertility of the soil organic matter should be added, green manure crop such as dhaincha (Sesbania aculeate) or sun hemp (Crotalaria junta) may be grown and incorporated into the soil which will improve the fertility, moisture holding capacity and physical condition of the soil.
Planting techniques and pit preparation for Litchi:
Litchi is an evergreen, spreading plant which attains the height of about 10-12 m at its full grown stage. The light penetration on its canopy is also desirable for proper fruiting, hence planting in a square system at the distance of 9-12 m. Within and between the rows has been advised. This will also help in cultural operations to be performed conveniently. However, planting of litchi in double hedge row system at a distance of 4.5×4.5×9 m accommodating 329 plants/ha and medium density at 6×6 m accommodating about 278 plants/ha have been suggested.
Before planting, a pit of 90x90x90 cm dimension to be dug at a marked place during the summer season in the month of April-May and soil should be spread on the ground. During this process, the harmful insect and pest will be minimized/controlled. Further, the pit should be filled with top soil mixed with about 40kg decomposed FYM/ compost, 2 kg neem/ karanji cake, 1 kg bone meal/ single super phosphate, 200-300 g muriate of potash, 20 g carbofuran 3G just before the onset of monsoon. About two baskets of soil from the root zone of old litchi tree also added which will be helpful for the mycorrhiza growth. Then the soil may be allowed to settle properly during first few spots of rain and get leveled properly.
During planting time a hole of about the size of earth ball to be made in the center of the pit at marked point and planting is done. After proper fixing of the plants, preparation of ring and watering is done immediately for proper establishment of the plant. The further plant is regularly irrigated till it is properly established.
Time of Planting:
Litchi should be planted during the rainy season which provides optimum soil moisture and better atmospheric humidity for a survival of the plants. Litchi is an evergreen plant, and atmospheric humidity helps in better establishment and survival of the plants. Hence in North India planting may be done from mid-June to end of August avoiding peak rainy period, if there is a problem with water logging in the field. Early planting provides longer rainy period for the initial establishment and growth. About one-year-old air-layered plants are ideal for planting in the field.
Protection of young plants:
During the winter months, excessive exposure to low temperature and in summers, exposure to scorching sun, lead to mortality of the newly planted litchi saplings. Thatching of plants from three sides leaving the east side open with locally available weeds/paddy straw supported on 1.5m long three bamboo sticks during the October-February and March-June is essential for the ensured establishment of the saplings. Mulching with paddy straw or local weed in the rings of the plants also improves establishment by maintaining proper moisture conditions near the root zone. Care should be taken for control of white ants, leaf cutters, etc. immediately after notice.
Intercropping:
Litchi is one of the fascinating fruit crops. In pre-bearing orchards up to 7-8 years, sufficient space is available in between the plants, that can be used for growing intercrops. Vegetable and flower crops have ample scope for cultivation in such interspaces. Moreover, these plants fit well in crop rotation to get more return per unit area and time. The crop rotation of cowpea-gladiolus is the best, followed by okra-potato-cowpea and cowpea-cabbage-onion. These intercrops are beneficial as they provide additional income to farmers, improving the growth of litchi. In the adult and junior adult bearing litchi orchard, there is vacant area among the litchi plants which can be well utilized for partial shade loving plants like Amorphophallus, turmeric
Water requirement for litchi:
Optimum soil moisture and humid microclimate in the orchard is of utmost importance for growth development and fruit production in Evergreen litchi plants. For the places receiving about 1000 mm annual rainfall distributed for a longer period, litchi can be grown successfully, and supplementary irrigation is required only during fruit development and maturity of the crop. However, during the initial 3-4 years of the establishment of the plant, much care is needed to protect the plants from extreme weather conditions. Protection of young plants from extreme temperature during summer and winter months is very essential in the initial stage of establishment. The young litchi plant must be irrigated at weekly interval for better establishment. Desiccating winds during summer and frost during winter months are most damaging.
The young litchi plant must be irrigated at weekly interval for better establishment. Desiccating winds during summer and frost during winter months are most damaging. Further, the young plants should be watered during the dry period and winter months at the interval of 10-15 days. In the basin, weed should be removed, and soil should be loosened. Mulching with dry local weeds in the basins help in better moisture conservation in young plants. In situ water harvesting through full-moon- terrace during the rainy season and mulching with paddy straw in October helps in maximum soil water retention and improves the fruit yield and quality in grown up plants. The land should be ploughed time to time to minimize the weeds and to improve the soil physical condition.
Irrigation at the interval of 2-5 days to maintain the atmospheric humidity during fruit development and maturity is pre-requisite for successful litchi cultivation. Irrigation of plants at alternate days interval, six weeks before harvesting improves fruit retention and fruit development, and reduces fruit cracking and improves the fruit quality. Moisture conservation through mulching using dried weed or black polythene sheet has been found useful. Certain physiological disorders like poor sex ratio, reduced fruit set, dark fruit drop and high fruit cracking, besides sun burning of the fruits can be minimized with proper water and nutrient management.
In the first week of April, when fruit development starts, water management becomes essential. Thus, light irrigation at an interval of 4-5 days during April and May promotes aril development and checks fruit cracking. Irrigation of litchi tree through drip system from fruit set stage has been found highly beneficial in minimizing cracking and improving the fruit quality.
Insect pest and disease management for Litchi:
The litchi is prone to attack by pests and diseases, which are one of the major limiting factors in its successful production of temperate fruits. Estimates of yield losses caused by pests and diseases attack range from 10 to 30 percent in various parts of the country during different seasons of the year. Unlike agriculture crops, litchi is grown as a monoculture, the pest and disease problems are entirely different and complex in nature. Such pest and disease situations have led to repeated and excessive use of chemical pesticides. This has resulted in the development of resistance in the pest species, contamination of fruits, environmental pollution as well as the rejection of export produce.
Integrated Pest Management requires preplanning even before establishing the orchard which includes the selection of suitable site, type, improved and pest/ disease free planting materials, regular pest/disease and weather monitoring in the orchard. Balanced used of fertilizers, water management, proper training and pruning, improved cultural practices, augmentation and conservation of parasitoids and predators, application of biopesticides and neem based formulation and need-based use of particular pesticides. To promote greater IPM implementation, particular emphasis is necessary to generate increased awareness and transfer of available realistic IPM programs. The strategic steps will include determination of farmers pest management knowledge, attitude and practices, IPM trial demonstrations and appropriate training of the extension personnel and farmers.
1.Eriophyde mite/Erinose mite (Aceria litchi )
It is a serious pest of litchi. Nymphs and adults, both infest litchi leaves and inflorescence. The adult insects are small and hardly visible with naked eyes. They live at the base of hairs on the under surface of the leaves. The mites puncture and lacerate the tissues of the leaf with their stout rostrum and suck the cell sap. The affected young leaves develop yellow or greyish-yellow color which later turns brown. On matured leaves, there are continuous or scattered patches of brown to deep-brown depressed regions with the ultimate result of gall formation, curling, twisting, thickening and pitting of the affected leaves. The upper surfaces of the leaves give a characteristic grayish or dried appearance. The leaves may ultimately fall off.
Mites have been found to attack and cause malformation of the inflorescence. The affected flowers or buds show an enormous increase in size is thickened with yellow color. An enlargement up to 4-5 times the average size is not rare. In affected flowers, the calyx is highly enlarged and sharply divided at the top showing the presence of 4 or 5 sepals. The peduncle is highly thickened and elongated. Some affected flowers have been found to develop highly thickened and elongated bracts, though they are usually ebracteate. The ultimate result is extremely low or ‘no’ fruit set.
Management
Prune off the affected plant parts as soon as the mites make their first appearance and burn the wastes fallen on the ground.Deep ploughing of the field and exposing the soil to the sun (May-June and Sept- October) helps in minimizing its incidence.Spraying of dicofol (0.05%) is found most useful to control the mite.
2.Bark eating caterpillar (Inderbela spp.)
The attack of caterpillar can easily be detected by the presence of brownish ribbon –like loose masses of excreta which remain attached to the main scaffold branches at the point of injury. The adult moth lays eggs during May-June in groups of 15-25 which hatch after 8-11 days. The larvae web shelters of wood, silk, and excreta and feed on the surface of the bark till September. After wards, they bore into the bark and underlying tissues in the branches. These become fully grown up by December and pupate in late April.
Caterpillars bore inside the trunk or main stem/branches about 150-250 mm deep. At night they come out and feed on the bark protected by large silken webs that cover the entire affected portion. Later, they eat through the bark into the wood and in the case of severe infestation with and the trees get revitalized and cease to flush.
Management
Orchard sanitation is simple, but important preventive measure in controlling bark eating caterpillar.Clean the affected portions of the tree by removing all the webs and insert the cotton wool into the holes, soaked in petrol or monocrotophos or dichlorvos and then seal the holes with mud.
3.Shoot borer (Chlumetia transversa W.)
The caterpillars bore inside the newly growing shoot and feed inner pats resulting in drying of the twigs. In the case of severe infestation, the sap movement is interrupted, and the tree ceases to flush.
Management
Pruning and burning of affected twigs minimize its infestation.Spraying of carbo sulfane 0.05% or quinalphos 0.05% is sufficient to control this pest.
4.Fruit borer (Conopomorpha cramerella Snaller)
It is a major pest of litchi, causes maximum damage during fruit developmental stage. The small caterpillars bore through the stalk end of the fruit feed on the seed and skin of the fruit. As a result, fruits become stalk end of the fruit. High humidity and intermittent rains favor its infestation. This pest also causes fruit drop.
Management
Regular ploughing, removal of wrapping materials, weed destruction, burying of damaged fruits help in controlling the incidence of this pest. Spray neembicidine or Kamcthenu Keet Niyantrak (4-5 ml/liter) two times at seven days interval. Use it at color break stage to minimize the incidence of the borer.
Application of imidacloprid 0.05% gives a good result. First spraying should be done at pea stage and second, 15-20 days after the first spray.
Source-National Research Centre on Litchi.
