Mango (Mangifera indica L.) is the most important fruit of India. It is grown over an area of 1.23 million hectares in the country producing 10.99 million tonnes. It accounts for 22.1 per cent of total area (5.57 million ha) and 22.9 per cent of total production of fruits (47.94 million tonnes) in the country. Though Uttar Pradesh has the largest area of 0.27 million hectares under mango, Andhra Pradesh has the highest productivity of 12 tonnes per hectare. While Andhra Pradesh produces 3.07 million tonnes of mango, U.P., Bihar and Karnataka produce 2.39, 1.79 and 0.92 million tonnes, respectively. India ranks first among world’s mango producing countries accounting for 52.63 per cent of the total world’s mango production of 19 million tonnes.
Mango is very well adapted to tropical and subtropical climates. It thrives well in almost all the regions of the country from sea level to an altitude of 1500 m, i.e., from Cape Comerin to Himalayas. However, it cannot be grown commercially in areas above 600 m. Temperature, rainfall, wind velocity and altitude are the main climatic factors which influence its growth and fruiting. It cannot stand severe frost, especially when the tree is young. High temperature by itself is not so injurious to mango, but in combination with low humidity and high winds, affects the trees adversely.
Most of the mango varieties thrive in places with good rainfall (75 to 375 cm per annum) and dry season. The distribution of rainfall is more important than its amount. Dry weather before blossoming is conducive to profuse flowering. Rain during flowering is detrimental to the crop as it interferes with pollination. However, rain during fruit development is good but heavy rains cause damage to ripening fruits. Strong winds and cyclones during the fruiting season can play havoc as they cause excessive fruit drop.
Mango grows well on wide variety of soils, such as lateritic, alluvial, sandy loam and sandy. Although it grows very well in high to medium fertility soils, its cultivation can be made successful even in low fertility soils by appropriate management especially during early stages of growth. Very poor and stony soils on hill slopes should, however, be avoided. The loamy, alluvial, well drained, aerated and deep soils rich in organic matter with a pH range of 5.5 to 7.5 are most for mango cultivation. The extremely sandy, shallow, rocky, water-logged, heavy textured and alkaline or calcareous soils are not suitable for mango cultivation.
There are more than thousand mango varieties in India. However, only about 30 varieties are grown on commercial scale in different states.Important mango varieties cultivated in different states of India
Banganpalli, Bangalora,Cherukurasam, Himayuddin, Suvarnarekha
Bombai, Langra, Fazri, Himsagar, Kishen Bhog, Sukul, Bathua
Fernandin, Mankurad, Alphonso
Alphonso, Kesar, Rajapuri, Vanraj
Dashehari, Langra, Bombay Green
Alphonso, Bangalora, Mulgoa, Neelum, Pairi
Mundappa, Olour, Pairi
Alphonso, Bombai, Langra and mostly seedling types
Alphonso, Kesar, Mankurad, Mulgoa, Pairi
Baneshan, Langra, Neelum, Suvarnarekha and mostly seedling types
Dashehari, Langra, Chausa
Banganpalli, Bangalora, Neelum, Rumani, Mulgoa
Bombay Green, Dashehari, Fajri, Langra, Safeda Lucknow, Chausa
Bombai, Himsagar, Kishan Bhog, Langra
Characteristics of important Indian varieties
1. Alphonso : This is the leading commercial variety of Maharashtra state and one of the choicest varieties of the country. This variety is known by different names in different regions, viz. Badami, Gundu, Khader, Appas, Happus and Kagdi Happus. The fruit of this variety is medium in size, ovate oblique in shape and orange yellow in colour. The fruit quality is excellent and keeping quality is good. It has been found good for canning purpose. It is a mid season variety
2. Bangalora : It is a commercial variety of south India. The fruit size is medium to large, its shape is oblong with necked base and colour is golden yellow. Fruit quality is poor. Keeping quality is very good. It is widely used for processing. It is a mid season variety.
3. Banganpalli: It is a commercial variety of Andhra Pradesh and Tamil Nadu and also known as Chapta, Safeda, Baneshan and Chaptai. Fruit is large in size and obliquely oval in shape. The colour of the fruit is golden yellow. Fruit quality and keeping quality are good. It is a mid season variety and is good for canning.
4. Bombai : It is a commercial variety from Bihar state. It is also known as Malda in West Bengal and Bihar. Fruit size is medium, shape ovate-oblique and colour yellow. Fruit quality and keeping quality are medium. It is an early season variety.
5. Bombay Green : It is commonly grown in north India due to its early ripening habit. It is also called Malda in Northern India. Fruit size is medium, shape ovate oblong and fruit colour is spinach green. Fruit quality is good and keeping quality is medium. It is a very early variety.
6. Dashehari : This variety derives its name from the village Dashehari near Lucknow. It is a leading commercial variety of north India and one of the best varieties of our country. The fruit size is medium, shape is oblong to oblong oblique and fruit colour is yellow. Fruit quality is excellent keeping quality is good. It is a mid season variety and is mainly used for table purpose.
7. Fajri : This variety is commonly grown in the states of Uttar Pradesh, Bihar and West Bengal. Fruit is very large, obliquely oval in shape. Fruit colour is light chrome. Fruit quality and keeping quality are medium. This is a late season variety.
8. Fernnadin : This is one of the oldest varieties of Bombay. Some people think that this variety originated in Goa. Fruit size is medium to large, fruit shape is oval to obliquely oval and fruit colour is yellow with a red blush on shoulders. Fruit quality and keeping quality are medium. It is a late season variety mostly used for table purpose.
9. Himsagar : This variety is indigenous to Bengal. This is one of the choicest varieties of Bengal and has gained extensive popularity. Fruit is of medium size, ovate to ovate oblique. Fruit colour is yellow. Both fruit and keeping quality are good. It is an early variety.
10. Kesar : This is a leading variety of Gujarat with a red blush on the shoulders. Fruit size is medium, shape oblong and keeping quality is good. It is an early variety.
11. Kishen Bhog : This variety is indigenous to Murshidabad in West Bengal. Fruit size is medium, fruit shape is roundish oblique and fruit colour is yellow. Fruit quality and keeping quality are good. It is a mid season variety.
12. Langra : This variety is indigenous to Varanasi area of Uttar Pradesh. It is extensively grown in northern India. Fruit is of medium size, ovate shape and lettuce green colour. Fruit quality is good. Keeping quality is medium. It is a mid season variety.
13. Mankurad : This variety is of commercial importance in Goa and in the neighbouring Ratnagiri district of Maharashtra. The variety develops black spots on the skin in rainy season. Fruit is medium in size, ovate in shape and yellow in colour. Fruit quality is very good. Keeping quality is poor. It is a mid season variety.
14. Mulgoa : This is a commercial variety of southern India. It is quite popular among the lovers of mango owing to high quality of its fruit. Fruit is large in size, roundish oblique in shape and yellow in colour. Fruit quality is very good. Keeping quality is good. It is a late season variety.
15. Neelum : This is a commercial variety indigenous to Tamil Nadu. It is an ideal variety for transporting to distant places owing to its high keeping quality. Fruit is medium in size, ovate oblique in shape and saffron yellow in colour. Fruit quality is good and keeping quality is very good. It is a late season variety.
16. Chausa : This variety originated as a chance seedling in the orchard of a Talukadar of Sandila district Hardoi, U.P. It is commonly grown in northern parts of India due to its characteristic flavour and taste. Fruit is large in size, ovate to oval oblique in shape and light yellow in colour. Fruit quality is good keeping quality is medium. it is a late variety.
17. Suvarnarekha : This is a commercial variety of Visakhapatnam district of Andhra Pradesh. Other synonyms of this variety are Sundari, Lal Sundari. Fruit is medium in size and ovate oblong in shape. Colour of the fruit is light cadmium with a blush of jasper red. Fruit quality is medium and keeping quality is good. It is an early variety.
18. Vanraj : It is a highly prized variety of Vadodra district of Gujarat and fetches good returns. Fruit is medium in size, ovate oblong in shape and colour is deep chrome with a blush of jasper red on the shoulders. Fruit quality and keeing quality good. It is a mid season variety.
19. Zardalu : This variety is indigenous to Murshidabad in West Bengal. Fruit size is medium, oblong to obliquely oblong and golden yellow in colour. Fruit quality is very good. Keeping quality is medium. It is a mid season variety.
i) Amarapali : This hybrid is from a cross of Dashehari x Neelum. It is dwarf, regular bearing and late maturing variety. The variety is suitable for high density planting as about 1600 plants may be planted in a hectare. It yields on an average 16 tonnes / hectare.
ii) Mallika : It is from a cross of Neelum x Dashehari. Its fruit is large in size, oblong elliptical and in shape cadmium yellow in colour. Fruit and keeping quality are good. It is a mid season variety.
iii) Arka Aruna : It is a hybrid between Baganpalli and Alphonso. It is dwarf regular bearing, precocious. Fruits are large having attractive skin colour with red blush free from spongy tissue.
iv) Arka Puneet : It is a hybrid between Alphonso and Banganpalli. It regular and prolific bearer. Fruits are medium sized having attractive skin colour with red blush and free from spongy tissue. Excellent keeping quality.
v) Arka Anmol : This hybrid is from a cron of Alphonso and Janardhan Pasand. It is regular bearer and good yielder. Fruits are medium sized having uniform yellow peel colour, excellent keeping quality and free from spongy tissue.
vi) Arka Neelkiran : It is a hybrid between Alphonso and Neelum. It is , regular bearering late season variety with medium sized fruits having attractive red blush free from spongy tissue.
vii) Ratna : This hybrid is from a cross of Neelum x Alphonso. Tree vigorous, precautions, fruits are medium sized, attractive in colour and free from spongy tissue.
viii) Sindhu : It is from a cross of Ratna x Alphonso. It is regular bearer, fruits medium sized, free from spongy tissue with high pulp to stone ratio and very thin and small stone.
ix) Au Rumani : It is from a cross of Rumani x Mulgoa. It is precocious, heavy and regular bearing with large fruits having yellow cadmium skin colour.
x) Manjeera : This hybrid is from a cross of Rumani x Neelum. It is dwarf, regular and prolific bearer with firm and fibre less flesh.
Other hybrid varieties released are Alfazali, Sundar Langra, Sabri, Jawahar, Neelphonso, Neeleshan, Neeleshwari and PKM2.
Mangoes are raised from seed or propagated vegetatively. Propagation from seed, though easy and cheap, is unable to perpetuate characters of the parent tree because most commercial varieties in India are cross-pollinated and monoembryonic. Plants also take more time to bear fruit. Accordingly, several methods of vegetative propagation have been tried with varying degree of success. However, it is essential to raise seedlings to be used as rootstocks. For this purpose, stones should be sown in June-July in beds mixed with well decomposed farm yard manure at the rate of 8-10 tonnes per hectare. Alternatively, 25 kg nitrogen (N) per ha may be applied in the form of urea, CAN or any other available inorganic source in two split doses at about two months interval after the leaves have become green. When the seedlings attain the age of 2-3 months, they should be transplanted well in prepared beds or pots one transplanting should be given in well prepared beds or pots. In this season, proper care should be exercised in irrigating the young transplanted seedlings. The seedlings should also be protected from frost by putting the pots under big trees or thatching the young seedlings in the field.
Plants are generally propagated using random seedling rootstocks. The polyembryonic rootstocks, however, have shown a promise in producing plants of uniform size and vigour. Moreover, these rootstocks have indicated possibility of inducing dwarfing and earlier bearing and are under test. Various methods employed in vegetative propagation of mango are described below :
a) Inarching : The method of inarching or approach grafting is quite cumbersome and time consuming, but it is still the leading method for commercial propagation of mango plants. The method consists of uniting the selected shoot (scion) of a desired parent tree (mother plant) with the potted or transplanted seedling (rootstock) by approach grafting. For this purpose, about one-year-old seedlings are most suitable when they attain a height of about 30-45 cm and thickness ranging from 0.75 to 1.5 cm. These seedlings are either grown in pots or under the mother plant from which the grafts are to be prepared, depending upon the availability of suitable branches. Generally, a one-year-old twig of the scion tree about 60 cm in length and nearly of the same thickness as that of the stock is chosen for grafting. Young and non-bearing trees should not be selected as mother plants.
Inarching should be done during the growing period when the tree is in active sap flow condition termed as active growth period. A hot and very dry period, as well as heavy rainfall during the inarching period is not suitable. The end of the monsoon in heavy rainfall areas and early monsoon in the light rainfall areas is the best period for inarching. In north India, July is the best month for inarching. In the more equitable climate of south India, the operation can be done any time between July and February.
A thin slice of bark and wood, about 5 cm in length, 7.5 mm width and 2 mm deep, is removed by means of a sharp grafting knife from the stem of the stock as well as from the scion branch. The dimensions can be proportionately increased or decreased according to the thickness of the stock and scion. The cuts thus made should be absolutely flat, clean, boat shaped, even and smooth. The ends of these cuts should be round and not angular. The cut surfaces of both, i.e., stock and scion are made to coincide facing each other so that there remains no hollow space between the two. These are then tightly tied by polythene / alkathene strips of about 1.5 cm in width and preferably of 200 gauge thickness, which has proved to be a good tying material.
After about one month of operation, the scion below the graft union and stock above the graft union should be given light ‘V’ shape cuts at weekly intervals such that grafts can finally be detached while giving the fourth cut. In the last stage, the top of the stock above graft union should also be removed completely.
b) Veneer grafting : This method of propagation possesses promise for mass scale commercial propagation. The method is simple and can be adopted with success. The rootstocks as mentioned, for inarching are suitable for this method also. For conducting this grafting operation, a downward and inward 30-40 mm long cut is made in the smooth area of the stock at a height of about 20 cm. At the base of cut, a small shorter cut is given to intersect the first so as to remove the piece of wood and bark. The scion stick is given a long slanting cut on one side and a small short cut on the other so as to match the cuts of the stock. The scion is inserted in the stock so that the cambium layers come on the longer side. The graft union is then tied with polythene strip as recommended for inarching. After the scion takes and remains green for more than 10 days the rootstock should be clipped in stages.
The scion wood to be used for veneer grafting requires proper preparation. The desired shoots should be defoliated at least one week prior to grafting so that the dormant buds in the axis of leaves become swollen. The best time for this method is the same for different regions as for inarching.
c) Budding : Although success of budding in mango was reported in the beginning of this century, budding still continues to remain in experimental stage as far as commercial mango propagation is concerned.
d) Stone Epicotyl grafting : Mango is generally propagated by inarchig and veneer grafting. These methods are time consuming. Stone epicotyl grafting is a new technique of mango propagation. This method is simple, cheap and quick. Fresh mango stones are sown in the nursery beds. After germination, seedlings with tender stems having coppery leaves are lifted with stones still attached. The roots and stones are dipped in 0.1 per cent Bavistin solution for 5 minutes after washing the soil. The seedling stems are headed back leaving 6-8 cm long stem. A 4-6 cm longitudinal cut is made running down through the middle of the stem. A wedge shaped cut starting on both sides is made on the lower part of scion stick. The scion stick should be 4-6 months old and 10-15 cm long containing plumpy terminal buds. The scion stick is then inserted in the cleft of the seedlings and tied with polythene strips. The grafts are then planted in polyethylene bags containing potting mixture. The bags are then kept in the shade protecting from heavy rain. When the scion sprouts and the leaves become green, the grafted plants should be planted in nursery beds. July is the most suitable month for stone grafting.
e) Soft-wood grafting : The technique of soft-wood grafting is similar to that of cleft or wedge grafting. In this case, grafting is done on newly emerged flush having bronze coloured leaves and stem. This method is useful in in-situ grafting. The scion wood to be used should be defoliated 10 days prior to the frafting and having same thickness as that of terminal shoot. The graft should be secured firmly using 1.5 cm wide and 4.5 cm long, 200 gauge polythene strip. July and August are the best months for soft-wood grafting.
f) Air layering : Air layering can be done successfully in mango using IBA or NAA 10,000 ppm in lanolin paste. Success up to 50 per cent has also been obtained by using Seradix-B as root promoter. The air-layers can be used for permanent planting or for raising uniform rootstocks.
Prior to planting, field should be deeply ploughed, harrowed and leveled. Pits of proper size should be dug at appropriate distances and filled by adding sufficient quantity of farm yard manure. The grafts to be planted should be procured from reliable nurseries few days before actual transplanting.
a) Time of planting : The best time for planting all over India is during the monsoon when there is sufficient moisture in the atmosphere. In the area, of heavy rainfall, the best time of planting mango is the end of the rainy season. In tracts where the rainfall is less, the planting can be done in the early part of the monsoon for better establishment. The planting should be done in the evening, otherwise if the day turns out to be unusually hot or dry, the plants may wither due to excessive loss of water. If the sky is overcast, planting can be done during day time also.
b) Planting distance : The planting distance varies according to variety, the fertility level of the soil and general growth conditions in the area. Where the growth is excessive, the distance should be 12 x 12 m, but in the dry zones where the growth is less, it can be regulated to about 10 x 10 m. For high density planting, the distance can be 5 x 3 or 5 x 2.5 or 3 x 2.5 or 2.5 x 2.5 meter.
c) Size of pits : In locations where the soil is loamy and deep, pits of 0.5 x 0.5 x 0.5 m be dug at desired distances. However, in shallow and hill soils, the pits should at last be of 1 x 1 x 1 m size.
d) Filling of pits : The pits should be filled with the original soil mixed with 50 kg well rotten farm yard manure. In the top two-third portion, the proportion of the manure and soil may be kept as 1:3. If the soil is having infestation of white ants, 200-250 g of aldrex or BHC dust may also be mixed.
In case of stony soils, it is better to remove all the stones from the excavated material and remaining soils should be mixed with soil scrapped from the left over area and FYM. The pits should invariably be filled before the rainy season, so that there is maximum settling down before the advent of heavy rainfall and much before planting.
e) Planting of grafts : The plant with its ball of earth intact should be taken out of the soil or pot. The plant can then be placed with the help of a planting board in the centre of the pit by excavating as much soil as necessary to accommodate the root-ball. The moist soil of the pit is then pressed all around the root ball to complete the the planting process. A small basin is then made and the plant is properly watered. The planting should not be done so deep as to bury the graft-union in the soil or so high as to expose the upper roots. It is always better to adjust it at the same height/depth at which it was in the pot or the nursery bed.
f) Training and pruning : Normally, mango trees require very less or no pruning. However, the training of the plants in the initial stages is very essential to give them proper shape. Specially when the graft has branched too low, the process of training becomes very important. At least 75 cm of the main stem should be kept free from branching and the first leader / main branch may be allowed after that. The main branches should be spaced in such a way that they grow in different directions and are at least 20-25 cm apart, otherwise there are chances of breakage due to smaller crotch angles and heavy top.
The branches which exhibit tendency of crossing and rubbing each other should be removed in the pencil thickness stage, otherwise they break by rubbing each other at a later stage and create complications. Secondly, if the centre is closed the fruits produced are of poor quality having less colouration in the absence of sufficient sunlight.
By following the above practice and after giving proper shape to the trees, there will be very less scope for future pruning except removal of diseased, pest infested or dried shoots / wood.
Nutrient uptake in mango is from large volume of soils. Therefore, it is able to sustain growth even in low fertility soils. But, its efficient management involves the replenishment of the nutrients used-up by the tree for its growth and maintenance, harvested produce and natural losses from soils through leaching and run of. Even the under-nourished trees can be revived by suitable supplementation of nutrients through fertilizers. The idea of manuring bearing trees is also to secure regular fruiting. Recommendations based on very limited research and also on experience gained by the orchardists are given below.
a) Quantity of fertilizer : Manuring mango plant starts right from planting operation in the orchard. First application is made at the time of filling of the pits (refer item 6 d). Fertilizer application during the first year of planting may be given as 100 g N, 50 g P2O5 and 100 g K2O per plant.
Above dose should be increased every year up to 10 years in the multiple of first year’s dose. Accordingly, a 10-year-old tree should receive 1 kg N, 500 g P2O5 and 1 kg K2O. This dose should be continued to be applied in subsequent years also. Application of 50 kg well-decomposed organic manure should be given four yearly to create proper soil physical environment. For trench application of fertilizers, 400 g each of N and K2O and 200 g of P2O5 per plant should be given.
The application of micronutrients is not recommended as a routine. Need based supplimentations are essential when these become limiting factor for production. It is advisable to apply micronutrients through foliar sprays.
b) Time of fertilizer application : Fertilizers may be applied in two split doses, one half immediately after the harvesting of fruits in June / July and the other half in October, in both young and old orchards, followed by irrigation if there are no rains. Foliar application of 3 per cent urea in sandy soils is recommended before flowering.
c) Method of fertilizer application : First of all, the weeds should be removed from basins. The mixture of recommended dose of fertilizers should be broadcast under the canopy of plant leaving about 50 cm from tree trunk in old trees. The applied fertilizer should be amalgamated well up to the dept of 15 cm soil.
To increase fertilizer use efficiency, fertilizers should be applied in 25 cm wide and 25-30 cm deep trenches dug around the tree 2 m away from trunk.
Amount and frequency of irrigation depends upon the type of soil, prevailing climatic conditions, especially rainfall to be given, and its distribution and age of trees. No irrigation is required during the monsoon months unless there are long spells of drought. During the first year when the plants are very young with shallow root system, they should be watered every 2-3 days in the dry season. Trees in the age group of 2-5 years should be irrigated at 4-5 days interval. The irrigation interval could be increased to 10-15 days for 5-8 years old plants during dry season. When trees are in full bearing stage, generally 2-3 irrigations are given after the fruit set. Profuse irrigation during 2-3 months proceeding the flowering season is not advisable. Irrigation should be given at 50 per cent field capacity.
Generally, intercrops are grown during the early years of plantation and hence frequency and method of irrigation has to be adjusted accordingly. It is advisable to irrigate the mango plants in basins around them which can be connected in series or to the irrigation channel in the center of rows. The intercrops need to be irrigated independently as per their specific requirements. In monocropping of mango also, basin irrigation is preferable with a view to economise water use.
Interculture in orchards is necessary for the proper upkeep of mango plantation. The removal of weeds not only avoids the competition for essential nutrients but also creates better physical soil environment for plant growth, particularly root development. It also helps in water movement in soil and in controlling some of the insect pests. Moreover, it ensures proper incorporation of the applied plant nutrients in soil and reduces their loss. Frequency and the time of interculture operations vary with age of the orchards and existence of intercrops.
Immediately after planting the mango, the weed problem may not exist, but it is advisable to break the crust with hand hoe each time after 10-15 irrigations. However, subsequent hoeing may be done depending on weed growth in the basin. If the intercrops are not being raised in the pre-bearing stage due to some reasons, the area between the basins should be ploughed at least three times a year, i.e., pre-monsoon, post-monsoon and in the last week of November.
Interculture operations are equally important for the bearing mango orchards. First ploughing should be done before the onset of rains. This will help in checking run-off losses and facilitate maximum retention of water in the soil. Orchard may be ploughed again after the rainy season is over in order to supress weed growth and to break capillaries. Third ploughing may be done in the last week of November or first week of December with a view to checking the population of mango mealy bugs.
Mango orcharding provides an opportunity for utilizing the land space to its maximum during initial years (up to 8-10 years) of establishment. Due to wide spacing and developing root patterns, the large unutilized interspace can be exploited for growing inter and mixed crops successfully. The soil fertility can also be maintained / enhanced by careful selection of intercrops and adequate management of the orchard. This enables the orchardists to raise extra income during the years when the main crop yields no / low returns. However, selection of intercrops depends on agroclimatic region, marketing facilities, levels of inputs and other local considerations. It is always advisable to avoid tall growing exhaustive crops like maize, sugarcane, bajara, etc. Some fertility restoring crops like legumes and leguminous cover crops should be included into the intercropping patterns. The partial shade loving crops like pineapple, ginger, turmeric, etc. can be grown in fully grown orchards. In addition to field crops, some short duration, less exhaustive and dwarf type inter-fillers like papaya, guava, peach, plum, etc. can also be grown till these do not interfere with the main mango crop. These inter-fillers can be selected depending on region and other considerations. Leguminous crops of like greengram, blackgram, gram; etc., cereals like wheat; oilseeds like mustard, sesame and groundnut and vegetables crops such as cabbage, cauliflower, tomato, potato, brinjal, cucumber, pumpkin, bittergourd, tinda, lady’s finger, etc. and spices like chillies can be successfully grown as intercrops. Some of important crop rotations recommended are as follows :
1.Cowpea-potato, 2.Greengram-wheat, 3.Blackgram-wheat, 4. Greengram-gram, 5.Blackgram-gram, 6.Cowpea-wheat, 7.Cowpea-gram
Maximum monetary return can be obtained from cowpea-potato rotation.
REJUVENATION OF MANGO ORCHARD
In general, 40-45 years old mango trees exhibit decline in fruit yield because of dense and overcrowded canopy. The trees do not get proper sunlight resulting in decreased production of shoots. New emerging shoots are weak and are unsuitable for flowering and fruiting. the population of insects and pests builts up and the incidence of diseases increases in such orchards. These unproductive trees can be converted into productive ones by pruning with the technique developed at the Institute.
Intermingling, diseased and dead branches are removed. Thereafter undesirable branches of unproductive trees are marked. At the end of December, these marked branches are beheaded at 1.5 to 2.0 meter from distal end and the cut portions are pasted with copper oxychloride solution. During March-April, a number of new shoots emerge around cut portions of the pruned branches. Only 8 to 10 healthy and outward growing shoots are retained at proper distance so that a good frame-work is developed in the following years. These rejuvenated trees are fertilized with 2.5 kg urea, 3.0 kg single superphosphate and 1.5 kg muriate of potash per plant. The half dose of fertilizers is applied in the month of February and the other half at the end of June. the plants are irrigated at an interval of 15 days especially in the months of April, May and June for healthy growth of new shoots. In the first week of July 150 kg of compost per tree is also applied. Unwanted emerging new shoots are regularly removed to maintain the tree canopy and avoiding recrowding of the branches. It also helps in getting proper rourishment to retained shoots. After two years of pruning new shoots come into bearing and the yield of fruit increases gradually. Thus, old and unproductive trees are convered in to productive ones.
Mango suffers from several diseases at all stages of its life. All the parts of the plant, namely, trunk, branch, twig, leaf, petiole, flower and fruit are attacked by a number of pathogens including fungi, bacteria and algae. They cause several kinds of rot, die back, anthracnose, scab, necrosis, blotch, spots, mildew, etc. Some of these diseases like powdery mildew are of great economic importance as they cause heavy losses in mango production. Major diseases of mango and their control measures are discussed below.
a) Powdery mildew (Oidium mangiferae Berthet) : Powdery mildew is one of the most serious diseases of mango affecting almost all the varieties, It occurs up to latitude of 40o North and South of the equator. It may persist for longer period at an elevation of 600-1200 meters, in many African countries, south of the Sahara, the middle East, Southern Asia and America : from the Southern United States to Peru and Brazil.
The disease is reported to cause approximately 20 per cent crop loss in Maharashtra state alone. Sometimes, as high as 70-80 per cent crop loss has been recorded on individual plant basis.
The characteristic symptom of the disease is the white superficial powdery fungal growth on leaves, stalks of panicles, flowers and young fruits. The affected flowers and fruits drop pre-maturely reducing the crop load considerably or might even preven the fruit set. Rains or mists accompanied by cooler nights during flowering are congenial for the disease spread. The fungus parasitizes young tissues of all parts of the inflorescence, leaves and fruits.
Control : Following three sprays of fungicides at 15 days interval recommended for effective control of the disease :
Wettable sulphur 0.2 per cent (2 g Sulfex / lit. water).
Tridemorph 0.1 per cent ( 1 ml Calixin / lit. water).
Dinocap 0.1 per cent (1 ml / g Karathane / lit. water).
b) Anthracnose (Colletotrichum state of Glomerella cingulata Ston, Spaull and Schrenk) : The anthracnose disease is of widespread occurrence. The disease causes serious losses to young shoots, flowers and fruits under favourable climatic conditions of high humidity, frequent rains and a temperature of 24-32oC. It is also affects fruits during storage. The disease produces leaf spot, blossom blight, withertip, twig blight and fruit rot symptoms. Tender shoots and foliage are easily affected which ultimately cause ‘die back’ of young branches. Older twigs may also be infected through wounds which in severe cases may be fatal.
Depending on the prevailing weather conditions blossom blight may vary in severity from slight to a heavy infection of the panicles. Black spots develop on panicles as well as on fruits. Severe infection destroys the entire inflorescence resulting in no setting of fruits. Young infected fruits develop black spots, shrivel and drop off. Fruits infected at mature stage carry the fungus into storage and cause considerable loss during storage, transit and marketing. The fungus perpetuates on twigs and leaves of mango or other hosts. Varietal differences in susceptibility have been noted in India. In Kerala, maximum damage was observed on Neelum, whereas variety Edward was reported to be resistant. Since the fungus has a long saprophytic survival ability on dead twigs, the diseased twigs should be pruned and burnt along with fallen leaves for reducing the inoculum potential.
Control: Trees may be sprayed twice with Bavistin (0.1%) at 15 days interval during flowering to control blossom infection. Spraying of copper fungicides (0.3%) is recommended for the control of foliar infection.
c) Die back (Botryodiplodia theobromae Pat.) : Die back is one of the serious diseases of mango. The disease is prevalent in Rajasthan, Delhi, Tamil Nadu, Punjab, Haryana, Orissa, Gujrat, Maharashtra and Uttar Pradesh. The disease on the tree may be noticed at any time of the year but it is most conspicuous during Oct.-Nov. The disease is characterized by drying of twigs and branches followed by complete defoliation, which gives the tree an appearance of scorching by fire. The onset of die back becomes evident by discolouration and darkening of the bark. The dark area advances and young green twigs start withering first at the base and then extending outwards along the veins of leaf edges. The affected leaf turns brown and its margins roll upwards. At this stage, the twig or branch dies, shrivels and falls. This may be accompanied by exudation of gum. In old branches, brown streaking of vascular tissue is seen on splitting it longitudinally. The areas of cambium and phloem show brown discolouration and yellow gum like substance is found in some of the cells.
Control : (i) Prune the diseased twigs and spray with copper oxychloride (0.3%) on infected trees. Pruning should be done in such a way that the twigs are removed 2-3 inches below the affected portion. (ii) In small plants, pruning of twigs is followed by pasting of copper oxychloride.
d) Phoma blight (Phoma glomerata (Cords) Woll. Hochapf)
Phoma blight, a new disease of mango, was first reported at Central Mango Research Station, Lucknow. The disease was later detected in mango growing belt around Lucknow region. It is now gaining economic importance.
The symptoms of the disease are noticeable only on old leaves. Initially, the lesions are angular, minute, irregular, yellow to light brown, scattered over leaf lamina. As the lesions enlarge, their colour changes from brown to cinnamon and they become almost irregular. Fully developed spots are characterized by dark margins and dull grey necrotic centres. In case of severe infection such spots coalesce forming patches measuring 3.5-13 cm in size, resulting in complete withering and defoliation of infected leaves.
Control : The disease could be kept under control by spray of copper oxychloride (0.3%) just after the appearance of the disease and subsequent sprays at 20 day intervals.
e) Bacterial canker (Xanthomonas campestris pv. mangiferaeindicae) : Canker disease of mango, caused by a bacterium, is prevalent in Andhra Pradesh, Maharashtra, Karnataka, Kerala, Tamil Nadu, U.P., Bihar, Delhi, Haryana, Madhya Pradesh and probably in several other mango growing areas. Besides being pathogenic on several varieties of mango, the organism is capable of infecting wild mango, cashew nut and weeds as well. The disease causes fruit drop (10-70%), yield loss (10-85%) and storage rot (5-100%). Many commercial cultivars of mango including Langra, Dashehari, Amrapali, Mallika, and Totapuri are susceptible to this disease.
The disease is found on leaves, petioles, twigs, branches and fruits, initially producing water-soaked lesions and later turning into typical cankers. The disease first appears as minute water-soaked irregular lesions on any part of leaf or leaf lamina. The lesions are light yellow in colour but with age, enlarge and turn dark brown to black. They become angular, cankerous and raised, and are surrounded by chlorotic halos. Several lesions coalesce to form irregular necrotic cankerous patches. In severe infections the leaves turn yellow and drop off. Cankerous lesions appear on petioles, twigs and young fruits. The water soaked lesions also develop on fruits which later turn dark brown to black. They often burst open, releasing a highly contagious gummy ooze containg bacterial cells. The fresh lesions on branches and twigs are water soaked which later become raised and dark brown in colour with longitudinal cracks but without any ooze.
Seedling certification, inspection and orchard sanitation.
Three sprays of streptocycline (100 ppm) or Agrimycin-100 (100 ppm) after first visual symptom at 10-days intervals.
Monthly sprays of Bavistin (1000 ppm) or copper oxychloride (3000 ppm) were also found effective.
Precautions: Do not wait for appearance of the disease. The key to success for full control is to start application of fungicides before the infection has established.
f) Red rust ( Cephaleuros virescens Kunze) : Red rust disease, caused by an alga, has been observed in mango growing areas. The algal attack causes reduction in photosynthetic activity and defoliation of leaves thereby lowering vitality of the host plant.
The disease can easily be recognized by the rusty red spots mainly on leaves and sometimes on petioles and bark of young twigs and is epiphytic in nature. The spots are greenish grey in colour and velvety in texture. Later, they turn reddish brown. The circular and slightly elevated spots sometimes coalesce to form larger and irregular spots.
The disease is more common in closely planted orchards. Fruiting bodies of the alga are formed in humid atmosphere. The zoospores formed by the sporangia initiate fresh infections. Stem entry is achieved by way of cracks. The affected areas crack and scale off. In severe infection the bark becomes thickened, twigs get enlarged but remain stunted and the foliage becomes sparse and finally dries up.
Control : Two to three sprays of copper oxychloride (0.3%) is effective in controlling the disease.
g) Sooty mould (Meliola mangiferae) : The disease is common in the orchards where mealy bug, scale insect and hopper are not controlled efficiently. The disease in the field is recognis by the presence of a black velvety coating, i.e., sooty mould on the leaf surface. In severe cases the trees turn completely black due to the presence of mould over the entire surface of twigs and leaves. The severity of infection depends on the honey dew secretion by the above said insects. Honey dew secretions from insects sticks to the leaf surface and provide necessary medium for fungal growth. The fungus is essentially saprophytic and is non-pathogenic because it does not derive nutrients from the host tissues. Although no direct damage is caused by the fungus, the photosynthetic activity of the leaf is adversely affected due to blockage of stomata.
Pruning of affected branches and their prompt destruction prevents the spread of the disease.
Spraying of 2 per cent starch is found effective.
It could also be controlled by spray of Nottasul + Metacin + gumacasea (0.2% + 0.1% + 0.3%).
B. Postharvest Diseases : The mango fruit is susceptible tomany postharvest diseases caused by anthracnose (C. gloeosporioides) and stem end rot (L. theobromae) during storage under ambient condtions or even at low temperature. Aspergillus rot is another postharvest disease of mango.
Control : Preharvest sprays of fungicides could control the diseases caused by latents infection of these fungi. Postharvest dip treatment of fruits with fungicides could also control the diseases during storage. The following treatments are suggested.
(i) Three sprays of carbendazim (0.1%) orthiophante-methyl (0.1%) at 15 days interval should be done in such a way that the last spray falls 15 days prior to harvest.
(ii) Postharvest dip treatment of fruits in carbendazim (0.1%) in hot water at 52+1oC for 15 minutes.
More than 492 species of insects, 17 species of mites and 26 species of nematodes have been reported to be infesting mango trees, about 45 per cent of which have been reported from India. Almost a dozen of them have been found damaging the crop to a considerable extent causing severe losses and, therefore, may be termed as major pests of mango. These are hopper, mealy bug, inflorescence midge, fruitfly, scale insect, shoot borer, leaf webber and stone weevil. Of these, insects infesting the crop during flowering and fruiting periods cause more severe damage. The insects other than those indicated above are considered as less injurious to mango crop and are placed in the category of minor pests. A brief description of the biology and control of major pests of mango is given below.
a) Hopper : Of all the mango pests, hopper is considered as the most serious and widespread pest throughout the country. Idioscopus clypealis Lethierry,Idioscopus nitidulus (Walker)and Amritodus atkinsoni Lethierry are the most common and destructive species of hoppers which cause heavy damage to mango crop. Large number of nymphs and adult insects puncture and suck the sap of tender parts, thereby reducing the vigour of the plants. Heavy puncturing and continuos draining of the sap cause curling and drying of the infested tissue. They also damage the crop by secreting a sweet sticky substance which encourages the development of the fungus Maliola mangiferae, commonly known as sooty mould which affects adversely the photosynthetic activities of the leaves. A low population of hoppers has been recorded in mango orchards throughout the year but it shoots up during February-April and June-August. Shade and high humidity conditions are favourable for their multiplication. Such conditions usually prevail in old, neglected and closely planted orchards.
The female hoppers lay 100-200 eggs on mid rib of tender leaves, buds and inflorescence. In summers the total life cycle occupies 2-3 weeks.
a) Chemical : Three sprays of 0.15 per cent Carbaryl or 0.04 per cent Monocrotophos or 0.05 per cent Phosphomidon or 0.05 per cent Methyl Parathion have been found very useful in controlling the pest population. First spray should be given at the early stage of panicle formation. The second spray at full length stage of panicles but before full bloom and the third spray after the fruits are set and have attained pea stage are recommended.
b) Biological : Biological control agents such as the predators Mallada boninensis and Chrysopa lacciperda, the egg parasite Polynema sp. and a preparation of the fungus Beauveria bassiana are the important useful bioagents to control this pest.
c) Integrated Pest Management (IPM)
The continuous use of pesticides though control the pests but pose some other serious problems like killing of pollinators and natural enemies, development of resistance to insecticides and residues which are on fruits hazardous to human population. Besides, the high cost of pesticides, labour and maintenance of equipments are other limiting factors in pest control. Integrated pest management is gaining momentum to take care of these problems. To manage mango hopper pest, avoid dense planting and keep the orchard clean by regular ploughing and removal of weeds. Pruning of overcrowding and over lapping branches should be done in the month of December. Chemical spray is to be minimized necessary. Neem products may be included in the management schedule of the pest. The use of insect growth regulator Buprofezin (0.0125 %) is also suggested as one of the sprays.
Mealy bug : It is another major pest of mango in India and is widely distributed all along the Indo-gangetic plain. Drosicha mangiferae Green is the most common mealy bug and causes severe damage to mango crop throughout the country. Nymphs and adults suck the plant sap and reduce the vigour of the plant. Excessive and continuous draining of plant sap causes wilting and finally drying of infested tissue. They also secrete honey dew, a sticky substance, which encourages the development of a fungus Maliola mangiferae, termed as sooty mould.
The adult male is winged and small, female is bigger and wingless. The female, after copulation, crawl down the tree in the month of April-May and enter in the cracks in the soil for laying eggs in large numbers encased in white egg sacs. The eggs lie in diapause state in the soil till the return of the favourable conditions in the month of November – December. Just after hatching, the minute newly hatched pink to brown coloured nymphs crawl up the tree. After climbing up the tree they start sucking the sap of tender plant parts. They are considered more important because they infest the crop during the flowering season and if the control measures are not taken timely , the crop may be destroyed completely.
(i) Mechanical : Polythene (400 gauge) bands of 25 cm width fastened around the tree trunk have been found effective barrier to stop the ascent of nymphs to the trees. The band should be fastened well in advance before the hatching of eggs, i.e., around November – December.
(ii) Chemical : Application of 250 g per tree of Methyl Parathion dust 2 per cent or Aldrin dust 10 per cent in the soil around the trunk kills the newly hatched nymphs which come in contact with the chemical.
Spraying of 0.05 per cent Monocrotophos or 0.2 per cent Carbaryl or 0.05 per cent Methyl Parathion have been found useful in controlling early instar nymphs of the mealy bug.
(iii) Biological : Menochilus sexmaculatus, Rodolia fumida and Sumnius renardi are important predators in controlling the nymphs. The entomogenous fungusBeauveria bassiana is found to be an effective bioagent in controlling the nymphs of the mealy bug.
(iv) Integrated Pest Management (IPM) : The IPM schedule of mealy bug is very important and useful if timely operations are done. Flooding of orchards with water in the month of October kills the eggs. Ploughing the orchards in the month of November exposes the eggs to sun’s heat. In the middle of December, 400 gauge alkathene sheet of 25 cm width may be fastened to the tree trunk besides raking the soil around the tree trunk and mixing of 2 per cent Methyl Parathion dust. The dust may also be sprinkled below the atkathene band on the tree. The congregated nymphs below the band may be killed by any of the suggested insecticides. The above IPM schedule holds promise to control the mealy bug but spraying of neem product and the spores of the fungusBeauveria bassiana will further ensure the reduction of the pest population.
Inflorescence midge : The mango inflorescence midge, Erosomyia indica Grover Diptera : cecidomyiidae) is another major pest of mango. Recently, this pest has become very serious in certain pockets of Uttar Pradesh causing serious damage to mango crop by attacking both the inflorescence and the small fruits. The adult midge are harmless minute flies which are short lived and die within 24 hours of emergence after copulation and oviposition. The flies lay eggs singly on floral parts like tender inflorescence axis, newly set fruit or tender leaves encircling the inflorescence. The eggs hatch within 2-3 days. Upon hatching, the minute maggots penetrate the tender parts on which the eggs have been laid and feed on them. The floral parts finally dry up and are shed. The larval period varies from 7-10 days. The mature larvae drop down into the soil for pupation. The pupal period varies from 5-7 days. There are 3-4 overlapping generations of the pest spread over the period from January-March. Thereafter, as the weather conditions turn unfavourable, the mature larvae undergo diapause in the soil instead of pupating. They break diapause on the arrival of favourable conditions in following January.
The midge infests and damages the crop in three different stages. The first attack is at the floral bud burst stage. The eggs are laid on newly emerging inflorescence, the larvae tunnel the axis and thus destroy the inflorescence completely. The mature larvae make small exit holes in the axis of the inflorescence and slip down into the soil for pupation. The second attack of the midge takes place at fruit set. The eggs are laid on the newly set fruits and the young maggots bore into these tender fruits, which slowly turn yellow and finally drop. The third attack is on tender new leaves encircling the inflorescence. The most damaging one is the first attack in which the entire inflorescence is destroyed even before flowering and fruiting. The inflorescence shows stunted growth and its axis bends at the entrance point of the larvae. It finally dries up before flowering and fruit setting.
As the larvae pupate in the soil, ploughing of the orchards expose pupating as well as diapausing larvae to sun’s heat which kills them.
Soil application of Methyl Parathion also kills pupating as well as diapausing larvae in the soil. The insecticide in the soil should be applied after monitoring larval population on white sheet below the tree.
Spraying of 0.05 per cent Fenetrothion or 0.045 per cent Dimethoate or 0.04 per cent Diazinon at the bud burst stage of the inflorescence has been found effective in controlling the pest population.
In addition to the inflorescence midge, Erosomyia indica, two other gall-midges Dasineura amramanjarae Grover and Procystiphora mangiferae Felt have been found damaging the mango inflorescence. They infest and damage the floral buds of the inflorescence. The mature larvae of D. amramanjarae are red, whereas those of P. mangiferae are orange in colour. The larvae of the former species pupate in buds itself. The infested buds of D. amramanjarae have red coloured petals and hence can be identified easily. The infested buds of P. mangiferae swell and look bigger than normal buds. The control measures used for E. indicawere also found effective against these midges.
Fruitfly : The oriental fruitfly is one of the most serious pests of mango in the country which has created problem in the export of fresh fruits. Daccus dorsalis, D. zonatus and D. correctus are the most common fruitflies which cause serious damage to mature mango fruits. The adult flies are dark brown in colour and measure 7 mm in length and 4 mm across the wings. The females have tapering abdomen which ends in an ovipositor. The female punctures the outer wall of the mature fruits with the help of its pointed ovipositor and insert eggs in small clusters inside the mesocarp of mature fruits. After hatching, the larva feeds on the pulp of fruit which appears normal from outside, but drops down finally. The mature maggots fall down into the soil for pupation. The emergence of fruitfly starts from April onwards and the maximum population is recorded during May-July which coincides with fruit maturity. The population declines slowly from August to September after which it is non-existent up to March.
(i) Chemical : The adult fruitflies can be controlled by bait sprays of carbaryl (0.2%) + protein hydrolysate (0.1%) or molasses starting at pre-oviposition stage (first week of April), repeated once after 21 days. Another method to control these flies is to hang traps containing a 100 ml water emulsion of methyl euginol (0.1%) + Malathion (0.1%) during fruiting (April to June). About 10 such traps are sufficient for one hectare of orchard.
(ii) Integrated pest management (IPM)
Collection and proper disposal of the infested and dropped fruits.
Ploughing the orchards and exposing the diapausing pupae to sun’s heat. Releasing of parasite and predator during December to February are helpful in reducing the pest population.
Monitoring and destruction of emerging adult with methyl euginol traps.
Early harvesting of mature fruits.
Selective and need based bait spray.
Hot water treatment or vapour heat treatment (VHT) of fruits before storage and ripening for killing the larvae.
Scale insects : Scale insects were not considered serious pest on mango in any part of the country till recently, but of late, they have assumed the status of serious pest in certain parts of the country. Pulvinaria polygonata, Aspidiatus destructor, Ceroplastis sp. and Rastococus sp. are some of the most common scale insects infesting mango crop. The nymphs and adult scales suck the sap of the leaves and other tender parts and reduce the vigour of the plants. They also secrete honeydew which encourages the development of sooty mould on leaves and other tender parts of the mango plant. In case of severe scale infestation, growth and fruit bearing capacity of the tree is affected adversely. Among the above scale insects, P. polygonata is posing a serious threat to mango industry of western Uttar Pradesh.
Control : Pruning of the heavily infested plant parts and their immediate destruction followed by two sprays of Monocrotophos (0.04 %) or Diazinon (0.04 %) or Dimethoate (0.06 %) at an interval of 20 days have been found very effective in controlling the scale population.
f) Shoot borer (Chlumetia transversa) : This pest is found all over the country. Larvae of this moth bore into the young shoot resulting in dropping of leaves and wilting of shoots. Larvae also bore into the inflorescence stalk. The adult moths are shining grey in colour and measure about 17.5 mm with expanded wings. Hind wings are light in colour. Female moths lay eggs on tender leaves. After hatching, young larvae enter the midrib of leaves and then enter into young shoots through the growing points by tunnelling downwards. The full grown larva is dark pink in colour with dirty spots and measures about 22 mm in length. There are four overlapping generations of the pest in a year and it overwinters in pupal stage.
Control : The attacked shoots may be clipped off and destroyed. Spraying of Carbaryl (0.2%) or Quinalphos (0.05%) or Monocrotophos (0.04%) at fortnightly intervals from the commencement of new flush gives effective control of the pest. A total of 2-3 sprays may be done depending on the intensity of infestation.
Bark-eating caterpillar (Ludarbella quadrinotata) : This pest is found damaging a variety of plants including a number of fruit trees, forest trees and ornamentals all over India. The old, shady and neglected orchards are more prone to attack by this pest. Larvae of this moth feed on the bark and weaken the tree. The moth is light grey in colour with dark brown dots and measures about 35-40 mm with expanded wings. A single female lays about 300-400 eggs in batches on the bark. The full grown caterpillar is dirty brown in colour and is about 35-45 mm in length. The caterpillar spins brown silken web on the tree which consists of their excreta and wood particles. Larvae also make shelter tunnels inside the stem in which they rest. Larvae actually feed from April to December. There is only one generation in a year.
Control : Remove the webs from tree trunks and put emulsion of Monocrotophos (0.05%) or DDVP (0.05%) in each hole and plug them with mud.
Stem borer (Batocera rufomaculata)
Stem borer is widely distributed in India and attacks a variety of fruit trees including mango. Damage is caused by the grub of this beetle as it feeds inside the stems boring upward resulting in drying of branches and in severe cases attained stem also dies. Adult beetles, 35-50 mm in size, are stout and greyish brown in colour with dark brown and black spots. Eggs are laid either in the slits of tree trunk or in the cavities in main branches and stems covered with a viscous fluid. Full grown grubs are cream coloured with dark brown head and 90 x 20 mm in size. Pupation takes place within the stem. Beetle emerges in July-August. There is only one generation of the pest in a year.
Control : The pest can be effectively controlled by following the recommendations given for the control of bark eating caterpillar.
Shoot gall psylla (Apsylla cistellata) : It is a very serious pest of mango in many parts of India, particularly in Terai region of U.P., north Bihar and West Bengal. This pest creates green conical galls in leaf axis. The activity of the pest starts from August. The galls dry out after emergence of psyllid adults in March. The females lay eggs in the midribs as well as in lateral axis of new leaves. Nymphs emerge from eggs during August-September and crawl to the adjacent buds to suck cell sap. As a result of feeding, the buds develop into hard conical green galls. The galls are usually seen during September-October. Consequently, there is no fruit set.
Eggs are white while nymphs are flat and of pale yellow in colour. Adults are 3-4 mm long with black head and thorax and light brown abdomen. Female lays approx. 150 eggs during March-April and nymphs pass the winter inside the galls. There is only one generation of the pest in a year.
Control : The galls with nymphs inside should be collected and destroyed to prevent carryover of the pest. The pest can effectively be controlled by spraying Monocrotophos (0.05%) or Dimethoate (0.06%) or Quinalphos (0.05 %) at 2 week intervals starting from the middle of August. The use of same chemical for every spray should be avoided.
j) Leaf webber (Orthaga euadrusalis): The pest is attaining serious proportions. Its infestation starts from the month of April and goes up to December. Eggs are laid singly or in clusters within silken webbings on leaves. Upon hatching, the caterpillars feed on leaf surface by scrapping. Later, they make web of tender shoots and leaves together and feed within. Generally, 1-9 larvae are found in a single web. Pupation takes place inside the webs in silken cocoons. However, the last generation (December-January) pupates in the soil. The adult moths are medium sized and sombre coloured. Fully grown caterpillar measures 2.5 to 3 cm. They are brownish in colour with brown spots and whitish striation on the dorsal surface. The pupae diapause for about five to six months. The infestation is severe in shady conditions. Old orchards with lesser space between tree canopy have more infestation than open orchards.
Control : Pruning of infested shoots and their burning in the month of April to July is found effective. Raking of the soil around the base of the trees in January, after the last generation has pupated, helps in checking the pest population. Three sprays starting from the last week of July at 15 days interval with Carbaryl (0.2%) or Monocrotophos (0.05%)) or Quinalphos (0.05%) have been found effective in controlling the pest.
Stone weevil (Sternochetus mangiferae) : This insect is widely distributed in tropics. It is a common pest of mango in southern India. Another species, S. frigidus,of the pest is found in Assam and Bengal. Sweeter varieties such as Alphonso, Bangalora, Neelum, etc. are more prone to attack by this pest.
Female lays eggs on the epicarp of partially developed fruits or under the rind of ripening fruits. Newly emerged grubs bore through the pulp, feed on seed coat and later cause damage to cotyledons. Pupation takes place inside the seed. Discolouration of the pulp adjacent to the affected portion has been observed.
Eggs are minute and white in colour. Adult weevils are 5 to 8 mm long, stout and dark brown in colour. Life-cycle is completed in 40 to 50 days during June-July. Adults hibernate until the next fruiting season. There is only one generation in a year.
Destroying the affected fruits and exposing the hibernating weevils by digging the soil
Spraying the trees with Fenthion (0.01%)
a) Mango malformation : Malformation is widely prevalent in northern India, particularly in the states of Punjab, Delhi and western U.P. where more than 50 per cent of the trees suffer from this malady. The malformed panicles remain unproductive and are characterised by a compact mass of male flowers, greenish in colour and stunted in growth. The main and secondary rachis are thick and short and bear flowers with relatively larger bracts, sepals and petals as compared to normal flowers. The malformed panicles remain intact on the trees for a considerable period. Though research efforto made hitherts have not been able to ascertain its etiology, the complexity of the disorder is attributed cultural practices, nutritional, to many factors like, mites, fungal, viral, etc. hormonal imbalance. The exact cause and control of the malady is yet to be established. However, some remedial measures are recommended as follows :
Pruning of shoots bearing malformed panicles
Deblossoming of early emerged / infested panicles.
b) Biennial bearing : The term biennial, alternate or irregular bearing generally signifies the tendency of mango trees to bear a heavy crop in one year (On year) and very little or no crop in the succeeding year (Off year). Most of the commercial varieties of north India, namely, Dashehari, Langra and Chausa are biennial bearers, while south Indian varieties like Totapuri, Red Small, Neelum and Bangalora are known to be regular bearers. When a tree produces heavy crop in one season, it gets exhausted nutritionally and is unable to put forth new flush thereby failing to yield in the following season. The problem has been attributed to the causes like genetical, physiological, environmental and nutritional factors. For overcoming biennial bearing, deblossoming is recommended to reduce the crop load in the ‘On’ year such that it is balanced in in the ‘Off’ year. Proper maintenance of orchard by way of effectively controlling pests and diseases and regular cultural operations may also result in better performance of the tree every year. Soil application of Paclobutrazol (PP333) or @ 4 – 5 g per tree in the month of September resulted in early flowering with higher fruit set and yield. It may be applied every year for regular fruiting, particularly in young trees. The time of application may vary according to fruit bud differentiation.
Insecticides should not be sprayed at full bloom to avoid killing of pollinators.
Pests and diseases should be controlled in time by spraying the recommended pesticides only.
Introduction of beehives in the orchards during flowering season for increasing the number of pollinators.
The practice of monoculture of a particular variety may be avoided. In case of Dashehari, 5-6 per cent of other varieties should be planted in new plantations. In old orchards, where monoculture of a particular variety like Dashehari is followed, a few branches may be top worked with pollinizing varieties.
Pruning of old trees may be done to open the canopy.
Spraying of 300 ppm NAA may be done during October-November.
MATURITY, HARVESTING, PACKAGING AND STORAGE
(v) Mango Leather or Aam Papad : Homogenized mango pulp is taken and potassium metabisulphite is added to it @ 2 g per kg of pulp. The pulp is then spread on trays smeared without and kept for drying in solar dehydrator or sun. After drying of one layer, another layer is spread over it and kept for drying. The process is repeated as per desired thickness. Finally they are cut into pieces and wrapped in butter paper or polythene cellophane sheet.