• Mango, Mangifera indica Linnaeus. the king of fruits. has a premier status among the commercial fruits grown in India.
• It covers an area of approximately 1.01 m hectares. which is about one-third of the total area under fruit production in the country.
• Though India produces nearly 60 per cent of the world mango. i.e. 9.5 million tonnes. it stands fourth In the export of fresh and processed fruits.
• Unfortunately, this crop suffers regularly a colossal loss due to malformation, a serious threat to mango Industry .
• This malady is one of the most destructive in nature because the economic losses faced each year vary between 5-30 per cent.
• This malady has a special significance, as there is a restriction on the export of mango saplings from India.
• Considering the magnitude of losses and a number of causes listed, quite a few of entomologists. plant pathologists. physiologists and horticulturists have attempted to study the causes and control of this malady.
• Mango malformation is the production of thick vegetative shoots at the growing tip and transformation of floral parts Into a compact mass of sterile flowers.
• Two types of malformation have been observed namely. vegetative and floral malformation.

Vegetative Malformation

• This usually occurs in the young seedlings though some- times on grown up trees too, both grafted as well as seedling type.
• The numerous small shootlets, arising from apex of shoot or leaf axil, thickened and clustered together, giving the twig a broom like appearance commonly known as 'Bunchy Top'.
• If the seedlings are attacked apically at an early stage (3-4 month-old) they remain stunted and eventually dry up.
• But when the attack is at later stage the seedlings may continue to produce healthy as well as malformed growths.
• These malformed bunches dry up after a few months but the branches or twigs bearing them continue to grow in spite of the disease.
• Trees between 4 to 8 years age suffer the most (90.9 %) from vegetative malformation.
• The miniature leaves get crowded to the extent that shootlets and their branches are not distinguishable at a1l and they look like a bunch.
• The infected seedlings bearing bunchy outgrowth at apex remain stunted and die ultimately.
• In the older seedling plants, usually normal growth appears above the infected region.
• This structure is called as witches broom.
• The axillary buds get swollen and persist on mother tree for a longer time as dry masses.
• They also observed growth is produced again in the next growing season.
• They severely restrict the growth and appearance of inflorescence.

Floral Malformation

• This is an abnormal development of inflorescence in which individual flowers in a panicle get greatly enlarged with large discs and the peduncle bearing the flower is also much thickened.
• The affected panicles continue to bear flower buds even after the fruit setting in the normal panicles is over.
• The malformed flowers remain green for longer period and hang on the trees even after the fruiting season.
• The percentage of hermaphrodite flowers in a malformed panicle is very low and, therefore, such panicles rarely bear the fruits and if fruit setting takes place, at all, the fruits drop down at the pea stage size.
• The malformed panicles may be loose or compact.

(i) Loose

• The panicles are larger in size but open in shape.
• Main and secondary axes continue to grow and produce leafy scales or flowers.
• Normal flowers are suppressed and replaced by tiny, leafy structures or scaly leaves.
• The peduncle and its main secondary branchlets are much thickened and the whole mass takes the shape of a 'Witches' Broom or 'Bunchy Top'.

(ii) Compact

• The panicle is much stunted, the peduncle is thick and short with secondary branches crowded closely on it.
• The flowers are compact in the form of a bunch.
• This compactness is again of three types

(a) Heavy

• Panicles are very compact. due to crowding of flowers and keep growing, forming a heavy panicle.
• The head sometimes looks like cauliflower.
• This usually persists on the tree, with low percentage of perfect flowers (below one per cent) and no fruit setting.

(b) Medium

• Panicles are slightly less compact, the growth is not continuous though re greening may start after sometime.
• They persist on trees longer than the normal panicles.
• The percentage of perfect flowers varies between one and five.

(c) Light

• Panicles are difficult to distinguish from normal ones at a later stage though during development, they can be recognized by their compactness.
• In some varieties they may even bear fruits.
• The percentage of perfect flowers ate almost half that of the normal panicle.
• Fruit setting is appreciable.
• The pistils in malformed hermaphrodite flowers are usually non-functional and pollens exhibit poor visibility.
• The thickened rachis of panicle produces large number of flowers, but most of them remained unopened.
• The hermaphrodite, malformed flowers have 1 to 4 ovaries per flower as against 1 to 2 in normal flowers.
• The affected flowers showed hypertrophied development of stigma, style and ovary.
• These flowers show high degree of embryo degeneration.
• Both healthy and malformed panicles appear at a single growing point and the healthy ones bear normal fruits.

• Since then it has been reported from almost all the mango growing regions of India.
• It is widely prevalent in the north. while in south its incidence is rather sporadic.
• It has been reported from Bombay (Maharashtra, Gujarat), Uttar Pradesh and Punjab.
• The disease has also been recorded from Egypt, Pakistan, Middle East, South Africa, Israel. USA.
• Central. America and Mexico, Sudan, Cuba, Australia, Bangladesh and from United Arab Emirates.

• Since malformed inflorescence fails to produce fruits.
• The damage per affected tree may vary from 50-80% and in severe cases the loss may be almost total.
• The intensity is higher in western districts of Uttar Pradesh than in eastern districts.
• The highest incidence is recorded from Punjab.
• Delhi and western Uttar Pradesh where almost 50% plants were affected, whereas in eastern Uttar Pradesh, Maharashtra, Andhra Pradesh, Telangana and Tamil Nadu the incidence was hardly 10 %.
• While in Mysore it was only 5% and in Kerala as also around Kanyakumari typical malformation was not found at all.
• The incidence varies from season to season depending upon the climatic conditions.
• The temperature plays a major role as a rise in temperature reduces the disease incidence.
• 50-70% trees were attacked in north-western. North-Eastern and North-Southern India.
• A disorder causing deformation and blackening of the panicles and swelling of vegetative buds. With gall formation is reported for the first time from Florida.
• It resembles the malformation described in S.E. Asia but has not been reproduced under controlled conditions.
• In Jammu, 21-45% floral malformation was recorded.
• There was an increase in incidence of malformation in Telangana and Andhra Pradesh and more than 50% damage in Punjab.
• Delhi and western Uttar Pradesh. Due to this losses are as high as 86% in UP terrain.
• The region beyond Hyderabad is free from this malady.
• Malformed plants in the Varanasi district of Uttar Pradesh are surveyed and found that malformed plants were shorter and had shallower root systems than healthy plants and younger plants were more affected by the disease than older trees.
• It is suggested that pollution may be an important-factor.
• The relative susceptibility in 8 CVS and found that Bombay Green.
• Dashehari. Lucknow Safeda and Chausa bear high percentage of malformation (10.8-24.2%). while in CV Baramasi, it was 0.32-1.92%.
• They also found trees of age 6-15 years were highly susceptible than older trees of 16- 26 years age.
• They observed that CV Bhadauran was free from this malady.
• Studies conducted at CISH, Lucknow during 1978 and 1979 under conditions of natural infection in India on 122 CVS revealed that Lucknow Safeda had (98.0%), Dashehari (84.0%). Langra (72.0%).
• Malda (68.0%). Totapari (60.0%) and Baramasi (20.0%) infection.
• The CV Ilaichi is however, found free from this malady, as observed by the scientists of CISH. Lucknow.
• The most resistant cultivars to malforn1ation viz. Alib, Cherumani, Malda Handle and Dudhia Langra can be exploited for plantation in the area where severe malformation is there.
• These cultivars will also help in the development of new mango hybrids resistant to malformation.

• It is very difficult to understand the spread and transmission of this malady.
• General spread is from infected plants to the healthy seedlings/trees in nursery or orchards.
• It is on this context there is a quarantine problem in the export of grafted plants to many countries.
• Spread is by the vegetative propagation by Veneer grafting.
• The intensity of malformation in four zones from 500 to 850 metres height in Kangra, Hamirpur, Una, Bilaspur and part of Sirmour and Solan areas of Himachal Pradesh.
• It was observed that disease intensity varied considerably in different varieties.
• Maximum floral malformation was observed in cv Dashehari followed by Malda, Chausa and Langra.
• It was further observed that disease intensity was maximum in mango trees aged below 10 years and there was subsequent decline in the disease intensity as the age of tree increased.
• It was also observed that seedling mangoes showed minimum intensity of floral malformation.
• Infected rootstock was employed on healthy scion and vice-versa and found that involvement of certain malformation inducing principle in the infected plant parts.
• The effect of malformation on grafting success was studied and healthy stock on scion gave success up to 73-93 per cent while infected stock on scion gave success up to less than 50 per cent.
• The growth of such plants was found to be restricted.

• The causes of mango malformation are still a matter of controversy.
• There are a number of schools of thoughts and accordingly virus, fungus, mites, nutrients, role of C/N ratio.
• Carbohydrates, nucleic acids, amino acids, proteins, phenolic compounds, enzymatic activity in plants, phytohormones and occurrence of malformin like substances etc. are reported to play major role in the occurrence of the malady.

Acarological Approach

• The association of mites (Aceria mangiferae syn. Eriophyes mangiferae Sayed) with malformation of mango was first reported from Egypt.
• The association of this mite to cause both vegetative and floral malformation.
• In India, the malformation was not caused by any insect or mite.
• For the first time recorded a species of Eriophyid mite occurring in the malformed shoots from Poona and claimed it to be the disease inciting organism.
• These mites produce various types of galls and wooly excrescences on plants and in malformed inflorescences. the mites are present in large numbers in the meristematic regions and tender portion of the peduncle.
• The anatomy of the cortex and stele of the inflorescence is considerably transformed accompanied by the development of hyper-plastic cells.
• These mites are inter and intracellularly, inciting cell enlargement and rapid multiplication of undifferentiated type of tissue of the axially buds after the flowering season was over.
• Besides A. mangiferae, two more species of mites, namely, Typhlodromus castellanii Hirst and Typhlodromus sp. (probably asiaticus) causing both vegetative and floral malformation. Irritation is caused by T. castellanii leads to abnormal growth.
• Since Typhlodromus spp. are predatory mites these could not be associated with the malformation. A. mangiferae and four other predatory mites. viz. Typhlodromus rosanlali. T. rhenwnus. T. nesbitti and Chaloetogenes omatus. male lays 250.00.212.50 and 160.50 eggs in F. moniliforme.
• Larva From the egg hexapod feeding larva emerges which is glossy white in colour.
• After some time the larva had become inactive and reached to quiescent stage.
• The larval period lasted for 2.41, 2.83 and 3.00 days in F. moniliforme.
• PDA media and mango buds and leaves, respectively.
• Protonymph The protonymph later acquired a fourth pair of legs.
• This possesses a rudiment genital opening.
• The period lasted for 2.17, 2.67 and 2.84 days in F. moniliforme.
• PDA media and mango buds and leaves. respectively.
• Tritonymph From the resting protonymph emerged the tritonymph, closely resembling the adult.
• The tritonymph is globular and glossy white with contracted legs.
• This period lasts for 1.50, 1.75 and 2.33 days in F. moniliforme, PDA media and mango buds and leaves. respectively.
• Adult The male and female were identical without any visible differences.
• The female was opaque, white in colour and larger than the male.
• The females lived longer than males (18, 17 and 15 days in F. moniliforme.
• PDA media and mango buds and leaves, respectively).
• The body of the male was more slender with a smooth skinning cuticle.
• It lived 12.25, 11.75 and 10.67days F. moniliforme. PDA media and mango buds and leaves respectively.
• The life cycle is completed from egg to adult in 8.33 days in F. moniliforme. 9.75 days in PDA media and 11.75 days on mango leaves and buds.

Viral Approach

• A virus is the causal agent and this malady is either of viral in origin or due to any physiological disorder.
• Mites are acting as vector for transmitting this virus.
• Successful transmission of malformation by grafting or budding has been reported.
• However results from electron microscopy transmission, cultural and serological studies in India and Egypt have convincingly disapproved the involvement of a virus or mycoplasmal association.
• Seedlings did not show any development of disease symptoms.
• Also, they employed heat pretreatment (50-60⁰C) of bud woods before budding.
• However, no significant effect could be reported in making It free of the pathogen as in case of other infected planting materials.

Fungal Approach

Malformed inflorescence

The fungus, Fuswiwn moniliforme was found associated with the malformed tissues of mango. The malformed shoots appeared after 1 1/2 month of inoculation in the leaf axil reisolation of the same fungus could be made.

• This fungus is obtained from both floral buds and floral axis of the malformed plants.
• The author further observed that mites carry fungus on their bodies and that the injury caused by these mites provides a mechanism for the entry of pathogen into the tissues of the host plant.
• Mites plated on potato-dextrose-agar (PDA) media showed the presence of fungus.
• This fungus is internally localized in malformed areas and does not spread systematically all over the plant and that is why healthy and malformed branches can be seen on the same tree.
• The injury to the host plant may not however, be caused by the mites alone: other agencies, such as hail storms, lashing rains, birds, insects and even human beings may also injure the plants and provide entry of the pathogen.
• F. moniliforme is isolated from 61% of the mites from malformed parts of mango, which gives an indication of the, possibility of mites disseminating the disease.
• In old shoots of severely affected branches, the infection is systemic.
• The fungus is found in all the scars, infected twigs, inflorescence axis and flowers.
• In affected twigs, it is detected only in cortex and not in xylem or pith.
• These authors pointed out that presence of the mite is not essential and further referred that the disease is temperature sensitive.
• The fungus F. moniliforme. subglutinans has been identified as the one associated with malformation.
• The role of Fusarium moniliforme or F. oxysporum appears to be significant as symptoms were produced by fungal inoculation.
• It is also round that polypeptide-like symptoms (malformline) in malformed tissues while such substances were absent in healthy tissues and malformation symptoms by the use of pachlobutrazol and ethephon in mango trees and seedlings and in high density Dashehari plantation malformation was reduced significantly after six years from over 50% to 0.02%.
• A hypothesis is also proposed that the Fusarium produces malformine and causes malformation in mango which can be controlled by annual pruning soon after crop harvest followed by pachlobutrazol or a similar trizole application.

Physiological and Biochemical Approach

(a) C/N Ratio

• In general it is observed that during or after rainy season mobility of starch and nitrogen in the panicles begins and this induces new growth and fruit set in plants if appropriate C/N ratio is attained.
• C/N ratio was responsible for off season fruiting in malformed panicles.
• At right stage of C/N ratio, the pollen and stigma becomes viable; pollination occurs and fruits are set.
• These fruits ripen from November to February.
• Nitrogen and carbohydrate are mobile during active root growth.
• Certain changes take place in the physiology of the mango tree at the time of fruit bud differentiation, which induced the trees to become malformed during the next flowering year.
• It was observed that percentage of male flowers was high in malformed inflorescence.
• The amount of carbohydrate in the shoots bearing malformed inflorescence was invariably higher as compared to healthy ones.
• The pith cells were deformed and are packed with starch in the malformed panicles.
• The abnormal panicles contain more nitrogen.
• In Hemsagar variety, nitrogen was 4.7% in normal panicles and 13.6% in abnormal ones.
• This disturbed sex ratio in flowers could be attributed to the disturbed C/N ratio in the trees.
• The malformation may be responsible for deflating the auxin balance.
• The higher C/N ratio in diseased shoots than in healthy ones in Bombay Green mango.
• The higher C/N ratio is present in the leaves of healthy shoots than in those from malformed shoots in Dashehari mango.
• The lower C/N ratio is noticed in malformed panicles at all the stages and shoots bearing malformed panicles at all the developmental stages.
• They also observed that the malformed seedlings also showed lower C/N ratio than the healthy ones.

(b) Nutrients

• Various workers have worked on the effects of exogenous application of macro- and micro-nutrients on the reduction of malformation malady.
• The disease is not caused by the deficiency of micro-nutrients like nitrogen, phosphorous and potassium.
• The foliar spray of urea at monthly intervals during winter was helpful in reducing the intensity of the disease.
• The lowest levels of phosphorous and potassium coupled with increasing levels of' nitrogen were found and there was a commensurate decrease in the percentage of malformed panicles.
• Application of nitrogen (220 g/tree) reduce floral malformation.
• Application of higher levels of N (200 g/tree) and K (200 g/tree) reduced malformation from 80 to 40 per cent.
• The addition of K₂SO₄ to the soil around the roots. plus a trunk injection of monocrotophos (to combat but mite- infestation), inhibited floral malformation and reduced fruit drop. Insecticidal treatment alone was ineffective.
• The potassium metabisulphite (600 ppm), ascorbic acid (1100 ppm), naphthalene acetic acid (NAA at 200 ppm) and bavistin (carbendazim, 200 ppm) sprayed on 15-year-old Dasheharl and Samar Bahist Chausa mangoes effectively controlled malformation but to different extents.
• Bavistin proved to be most effective, with 95 and 91.3% disease reduction, respectively and ascorbic acid, the least (77.7 and 65.1 %).
• The enhanced nitrogen rates i.e. 300 g/tree half of which applied in March and the remaining half in October and found that floral malformation was reduced. He further observed that addition of phosphorus and potassium significantly increased the malady.
• The intensity of malformation was more in Mallika followed by Amarpali in comparison to Dashehari mango.
• Exotic cultivar Kensington was most susceptible to floral malformation.
• They also observed the lower rate of photosynthesis.
• lower leaf saccharides contents and higher rate of respiration in malformed mangoes.

(c) Pruning of Malformed Parts

• Pruning the malformed portion reduced the malformation intensity.
• By pruning the shoots 30-60 cm below the malformed panicles during July and observed that malformation is reduced in the subsequent years.
• The pruning as was done in Rajapuri cultivar in July or August and observed 98% control of malformation.
• The local disturbances in the metabolism of the shoot could be controlled by simply pruning the malformed panicles.
• When the panicles pruned along with 30cm of the shoot in July, there is reduction in malformation.
• Shoots of 22cm below the malformed inflorescence during flowering season and found that it reduced the incidence.
• The cutting scion sticks for grafting during August and September increased the incidence of malformation.
• Some experiments were conducted wherein pruning was done combined with foliar sprays of insecticides and fungicides and the results obtained were found to be encouraging.

(d) Chlorophyll

• The higher amounts of chlorophyll a, b and total chlorophyll were recorded in the leaves from both healthy and malformed shoots.
• The total chlorophyll contents in the leaves and shoots bearing malformed panicles was lower in comparison to shoots of healthy panicles.

(e) Carbohydrates

• The contents of carbohydrates in malformed panicles were usually found higher as compared to healthy panicles.
• The findings of earlier workers but they stated that this higher carbohydrate content was due to poor hydrolysis in to sugars.
• The lower carbohydrate contents are observed at all levels of malformed panicle development.
• The lower level of saccharides are noticed in malformed tissues and lower levels of reducing and non-reducing sugars while higher level of non-reducing sugars.

(f) Nucleic Acids, Amino Acids and Proteins

• The leaves of malformed shoots contain higher amounts of free and less amount of bound acids.
• The higher levels of RNA, DNA, soluble proteins, total amino acids and amides are reported in the healthy panicles in comparison to malformed ones.
• The lower levels of free amino acids in the leaves of malformed shoots of Dashehari and in malformed tissues higher amount of protein, RNA and DNA was found.
• Malformed panicles and shoots have lower DNA and basic amino acids.
• The neutral and aromatic amino acids were higher in malformed panicles at swollen bud differentiation stage.
• They also contained lower levels of arginine but higher values of tryptophan and aspartic acid at all stages of development.
• At fully grown stages there was a sharp decline in cysteine and methionine.

(g) Phenolic Compounds

• The higher levels of total phenols and reducing sugars in malformed and healthy shoots are observed.
• The higher levels of total phenol and ortho-dihydroxyphenols are reported in malformed shoots than the healthy ones.
• Mangiferin, elagic acid, gallic acid and galloyl derivatives of glucose were isolated in both malformed and healthy shoots and found a higher level of phenol in flowers than in rachis.
• The level of mangiferin was sub-supraoptimal in malformed panicles than in shoots and leaves.
• The higher levels of mangiferin had reported in the malformed panicles.
• It is said that the accumulation of mangiferin resulted in an excessive vegetative growth which subsequently leads to continued emergence of rudimentary leaves and leafy inflorescence bearing florets.
• They also reported the accumulation of mangiferin in the buds and the translocation of it caused malformed or healthy inflorescence.

(h) Enzymatic Activity

• The increase peroxidase and poly-phenoloxidases in malformed panicles was observed.
• The activity of IAA-oxidase, peroxidase and polyphenoloxidases were observed to be 350, 118 and 32% higher in malformed tissues respectively.
• An acceleration in action of oxidative enzymes was observed due to phenolic substances and it gave a positive correlation with enhanced enzymatic activity.
• The IAA-oxidase extracted from both malformed and normal inflorescence showed different mobility patterns in electrophoresis.
• The accumulation of mangiferin (1,3,6,7 - tetrahydroxyxanthone-C-B-D-glucocide) a natural metabolite of Mangifera indica was observed at the site of differentiating buds influences the change from reproductive to vegetative growth.
• Mangiferin induced physiological changes in M. indica have been studied and a link established between the metabolic deviations and the observed effects of mangiferin accumulation in healthy and malformed mango plants.
• Mangiferin in high concentration suppressed the activity of peroxidase, catalase, a -amylase and lAA-oxidase.
• Polyphenolaxidase and invertase showed increased activity.
• Mangiferin accumulation increased the rate of photosynthesis but decreased those of transpiration and respiration.
• Mangiferin treatment increased the contents of chlorophyll, carbohydrates, total nitrogen, protein nitrogen, nucleic acids (RNA and DNA) and indole-3-acetic acid (IAA).
• The lower nitrate reductase activity is observed in malformed buds and panicles.
• The influx of mangiferin into differentiating flower buds and developing panicles caused by biotic and abiotic stress factors tilted the hormonal balance in favour of vegetative growth causing malformation.
• Mangiferin metabolite of mango induced changes in isolates of F. moniliforme [Gibberella fujikuroi] from maize cobs and banana fruits.
• These included the production of more aerial hyphae but less pigment and an increase in parasitic ability but reduced saprophytic growth.
• The significance of mangiferin induced changes in evolving the host specific stress of the pathogen on mango is discussed.

(i) Phytohormones

(a) Auxins

• In general it is observed that the symptoms of this malady are linked with an imbalance between growth promoters and inhibitors.
• The higher level of inhibitors and lower level of all the four fractions of auxins are observed viz. free neutral, free acidic, bound-neutral and bound-acidic in malformed panicles of Dashehari cultivar.
• The lower levels of abscissic acid and higher promoter activity were observed in malformed panicles.
• The enhanced activity of auxins (acidic) is present in malformed buds.
• The decreased levels (98.4 and 9.26%) of IAA and 3-Indoleacetonitrite (IAN) were recorded.

(b) Gibberellic Acid

• The gibberellin like substance are increased in malformed panicles and they induced production of male flowers and in due course the growth of malformed panicles increased tremendously.
• Gibberellin content in malformed panicles is very low, and its activity was noted to be decreased at rapid growth stage of panicle.

(c) Cytokinins

• Cytokinins, Zeatin and Iso-pentenecyladenosine (2-IP) are present in the tissues.
• Generally the levels of cytokinins were observed higher in malformed panicles.
• Three schools of thoughts are proposed i.e. (i) production of 2-IP by the fungus F. moniliforme var. sub- gtutinans. (ii) increased production of Ribosyl Zeatin (AR) and Glycosyl-O-Zeatin (ZOG) in malformed tissues and (iii) blockade of the production of the Dihydrozeatin (D HZ) like compounds.

(d) Ethylene

• The high levels of ethylene are observed in both floral and vegetative malformation.
• It is observed that ethylene suppresses apical dominance, isodiametric growth of rachis and shortening and thickening of secondary panicles.

(e) Abscissic Acid

• The higher levels of abscissic acid was reported in both floral and vegetative malformation.
• It is observed that lower levels of IAA and GA and higher levels of Zeatin.
• Abscissic Acid and Ethylene caused inhibition of apical growth and appearance of bunchy top like symptoms.

(j) Malformin-Like Substances

• Malformin is a substance called cyclic-pentapeptlde produced by Asper-gitlus niger which is also reported to cause malformation in plant parts.
• Three types of mango inflorescence are studied viz. healthy (H) naturally malformed (N) and morphactin-induced malformed (M) of Dashehari, Mallika, Benazir and Taimuria cultivars, Morphactin (500 mg1-1) treatment drastically reduced the growth as well as the fresh weight of the panicles IAA oxidase activity was significantly different in the three types of panicles and ranged from 6.5m moles IAA/g tissue/h in Taimuria to 39.4 in Benazir for H. while it was from 25.5 in Taimuria to 51.0 in Mallika for N. However, for M it was more than double that for H. Catalase activity was the lowest for M followed by N and then H. Amylase activity did not exhibit any difinite trend.
• The lAA oxidase had a significant negative correlation with catalase and growth parameters.
• The increase in the activity of IAA oxidase by morphactin treatment which caused malformation-like symptoms. and the observed high activity of the enzyme in naturally malformed panicles suggest that malformation might be due to decreased levels of auxins or to hormonal imbalance.
• Malformin-A compound was recorded from the culture of F. moniliforme var .subglutinans from the strain isolated from mango plants.
• Some bioassay and chromatographic studies found three morphines viz. M1, M2 and M3.
• They further observed that morphine-A is similar to M3 and the roots and stem contain higher level of M3 and other morphines.
• The total chlorophyll, carbohydrate and protein contents and found that they were significantly more in malformed panicles of mango with a slow rate of respiration than healthy panicles.
• Morphactin Induced malformed panicles tended to result in a comparable level of biochemical constituents to that of naturally malformed panicles.
• There was strong correlation between degree of malformation and malformin contents.
• The corn root curvature bioassay for malformin was also found sensitive to ethephon and pachlobutrazole. suggesting malformin like affect of these chemicals along with possibility of utilization of this test for estimation of ethephon and pachlobutrazole activity.
• Malformation of mango panicles could not be controlled by iron, zinc nutrition. spray of growth regulators (NM, GA3, G1ycocel, Ethephon, 2,4-D. ABA, Anti-malformins. Antiethylene. Antibiotics, etc.
• The multiple buds identified either at the initial stage of growth (balloon) or bud-burst stage terminated invariably into malformed panicles in cvs. Amrapali and Dashehari.
• The extent of malformation increased in simple and multiple buds with their increased diameter at the initial bud growth and bud-burst stages in Dashehari and Amrapali.
• Multiple buds which 1ater terminated into malfom1ed panicles contained higher level of ABA, IAA, oxidise, ethylene, total phenols. total protein. nitrogen,potassium and magnesium and lesser content of IAA, GA3, C/N ratio. phosphorus, calcium, iron, Manganese, copper, zinc, sodium and polyphenol oxidase activity as compared to simple bud.
• Ruellia tuberosa L. Leaf extract applied at the time of flower bud differentiation in October significantly reduced floral malformation in cv. Dashehari.
• This reduction was found to be associated with an increase in IAA and p0lyphenol oxidase activity and decreased IAA oxidase activity, total phenol and ABA in the bud.
• NAA alone or in combination with irrigation applied in October did not reduced floral malformation in Dashehari, Chausa and Amrapali.
• However the mechanism as to how these malformin-like substances synthesized in the plant system is not fully known and hence it requires immediate attention.

• Since there are different schools of thoughts regarding the causes of this malady. attempts have been made by various workers to control it by application of plant growth regulators, nutrients, pesticides, phenolics, anti-malformins and malformin-antagonists. deblossoming with or without growth regulators and pruning without or in combination with pesticides.

1. Application of Plant Growth Regulators and Phenolic Compounds

• Spray of NAA (100 to 200 ppm) during the first week of October has been worked out to reduce floral malformation.
• Later, four sprays of 250 ppm NAA at weekly intervals from 20th October onwards have been suggested to reduce the intensity of malformation to the maximum possible.
• Spraying of 100 ppm NAA in first week of October was more effective.
• Hence. spray of 100 ppm NAA has been suggested instead of 200 ppm NAA.
• They also observed that spraying 200 ppm NAA in first week of October followed by spraying of 500 ppm of ethrel at bud inception stage during February was highly effective in reducing floral malformation.
• Spray of 400 ppm of Ethephon at bud inception stage reduced the floral malformation significantly.
• Increase in floral branches and yield was observed by the spraying of ethrel (250 or 500 ppm). or uniconazole 500 ppm in the month of December.
• The gibberellic acid at 50 ppm causes delayed panicle emergence, increased number of perfect flowers and increased pollen viability.
• Sprays in the months of October and November cause 50% reduction in malformation.
• Spraying of 1000 ppm Paclobutrazol (10-60 gm/tree), prior to FBD, during the first week of October reduced malformation, increased number of healthy flowers and increased the yield.

2. Deblossoming

• Deblossoming at the bud burst stage alone and in combination with the spraying of 200 ppm NAA was reported very effective.
• Deblossoming alone at bud burst stage gives substantial reduction in malformation; and alleviate panicle malformation however there is no effect of deblossoming in reducing the intensity of malformation.
• Malformed and healthy buds prior to deblossoming and found that only those buds which are free from malformation produced normal panicles and those having malformation produced diseased inflorescences and reported that there is no effect of deblossoming.
• The process of deblossoming is very cumbersome and hence it is advisable to develop a chemical for deblossoming purpose.
• The effect of abscission promoting chemicals e.g. ethephon (500 and 1000 ppm). M and B 25105 (250. 500. 1000 and 2000 ppm) and carbaryl (5000 and 10.000 ppm) on chemical deblossoming was studied in Dashehari and Chausa cvs. of mango.
• Ethephon affected almost a total kill of panicles irrespective of initial size at both the concentrations In Dashehari and panicles were completely shed within seven days of the treatment.
• M and B 25105 was slightly effective at lower concentrations while carbaryl was ineffective.
• In case of Chausa various treatments were found to be ineffective in inducing deblossoming.
• However, ethephon caused deblossoming of only smaller panicles.
• Different chemicals were also found to exert profound inhibitory effect on the growth of mango panicles as compared to the control to deblossom chemically.
• The application of 200 and 500 ppm ethrel to get complete control.
• The panicle can be deblossomied by applying 250 ppm of cycloheximide.

3. Use of Antagonists and Anti-Malformins

• These compounds were observed to reduce the activity of malformation and thereby reduced the extent of malformation.
• Glutathione of 2240 ppm and 2110ppm ascorbic acid to be very effective and malformed panicles turned healthy after 15 days of application.
• The chemical may be applied three times after appearance of malformation.
• The application of above compounds when the panicles are 4-6 cm long with the same results as reported.
• The reduced floral malformation was observed when ascorbic acid at 200 ppm was applied in the first week of October.
• The delayed panicle malformation and induced healthy panicles were observed with spraying of glutathione (560 ppm), AgNO₃ (2400 ppm), ascorbic acid (1055 ppm) and K₂S₂O₅ (560 ppm).

4. Application of Nutrients

• Soil application of N:P₂O₅:K₂O (9:3:3) causes high N and low P and K reduced floral malformation.
• Soil application of NPK + FeSO₄ and is noticed a reduction in malformation and increase in yield.
• The N reduced the floral malformation whereas high P and K had similar effect.
• By the spraying of mangiferin Zn2+ and Cu2+, the partial control is achieved and good control by injecting phosetyl-Al+Zn+B in the tree trunk.
• Reduction in floral malformation is achieved by cobalt sulphate ( 1000 ppm) when sprayed in first week of October .

5. Pruning of Malformed Parts

• Pruning reduces malformation.
• There is an increased malformation when cutting of scion sticks were used for grafting during August and September.
• Pruning followed by spraying with the mixture of fungicide (captan 0.1 %) .miticide (Akar 338-0.1 %) and sticker (Tenae) is effective against malformation.
• This spraying helped considerably in controlling at least the spread of the disease.
• Pruning of the diseased parts and spraying with diazinon to control this malady.
• The elimination of affected seedlings is advocated from nurseries.

6. Application of Pesticides

• The application of 0.04% diazinon controls malformation.
• Two sprays of 0.32% diazinon minimize the malformation.
• 99% control of the disease is attained by excising the desired shoots 300-600 mm below the inflorescence and burning them and spraying trees with 0.1% parathion.
• 0.1% thiometon after every three weeks.
• The simple removal of shoots In July and August had given 98% control with no disease for next two years.
• Fumigating of the grafted plants with methyl bromide (30-40 mg/litre) for 1-3 hour kills the adults and nymphs of mite.
• The recovery from malformation saplings is possible after pruning the seedling shoots except a terminal bud and few axillary buds and sprayed with 0.1% diazinon.
• Aphidon chlordane. diazinon. fenitrothion. mecarbam and disulfoton gave 100% kill at 0.03 and fenthion. phosphamidon.
• Phenthoate, azinphos-ethyl, methyl demeton and aldrin at 0.1% were equally effective against mite.
• The percentage of malformed panicles is recorded with lowest (12.9) in swabbing treatment of the out ends with diazinon and highest (40.38) with the pruning alone.
• Aldicarb. apocarb. dImethoate and phorate were most effec- tive against mite at 0.05 9 per plant.
• Pruning is coupled with sprays of an acaricide and a fungicide have shown some promise in reducing the malformation.
• It was found that 0.1% of diazinon, monocrotophos and phosphamidon were comparatively better in checking the infestation of bud mite, Acelia mangiferae.
• It was found that diazinoll was the best followed closely by 0.1% monocrotophos and chlorophenamidine, 0.3% phosphamldon, 0.1% parathion and methyl parathion and 0.25% WP sulphur in reducing the malformation, if sprayed from July to December at 21 days of interval.
• The complete control of the malady is achieved with the spraying of Fytolan (0.2%) once before inoculation followed by two sprays at 5 and 8 days intervals.

7. Effects of Polythylene Film Cover

• Polythylene film covers are used around mango shoot in winter. which controlled malformation.
• It is suggested that malformation can be controlled by raising temperature around the panicles or orchards in winter.
• The temperature can be attained by covering Amrapali mango tree by polythene tent before the onset of flowering.
• They observed that the tree covered with polythene sheet has faster rate of panicles emergence and completed their growth by last week of February whereas open trees had slower growth and completed their growth in the third week of March.
• It was observed that covered trees were observed free from malformation.
• They also suggested that malformation in the panicles takes place in winter and by increasing the temperature in the orchard by some suitable means during winter, malformation can be controlled with the advantage of early crops.
• Polythene cover raises the average temperature by 3°C around the tree as well as internal temperature of the leaf by 1°C concomitantly altered the physiological attributes resulting in early emergence of panicles with faster growth early fruit set and inhibition of malformation in them.

• The author is of the opinion that mango malformation is incited by the eriophyid mites.
• It is the feeding of these mites that leads to physiological disturbances in cell sap resulting in the abnormal growth.
• In addition the injury caused by these mites and also provides entry for the fungus which is often found associated with this malady.
• It has been further observed that the temperature plays a major role and is responsible for the low incidence of malformation in South India.
• In North India, during winter season the bud development remains in diapause and it is during this period that the mites cause severe damage, resulting in malformed growth.
• In South India there is no such diapausing period hence mites though present they are not in a position to cause sufficient damage to result in malformation.
• It has also been established that mites carry spores of the fungus and act as carriers.
• The over all effect of the mite and the fungus may be causing nutritional disbalance in the plant parts.
• The real disbalance of phenolic compounds enzymatic activity. phytohormones and malformin like substances needs to be examined systematically and to arrive at some conclusion.
• The control measures reported are impractical and controversial.
• It is therefore concluded that the orchards may be kept in good hygienic conditions and disease free planting material be used for planting.
• The orchards may be inspected quite frequently and any malady noticed may be removed from time to time.
• Pruning of malformed panicles and parts along with affected shoots (at least 30 cm) may be done regularly.
• It is observed by the author that systematic eradication of affected shoots and inflorescence resulted in gradual decrease in incidence of the disease.
• The Spraying of insecticides and fungicides may be done after pruning operation is over.
• The deblossoming at bud-burst stage alone or in combination with spray of 200 ppm NM prior to bud differentiation has been suggested and met with success, but manual deblossoming in a tree is rather impossible, hence a serious effort towards chemical deblossoming needs immediate attention.

• Survey for the malady and assessment of data for actual losses all over the world may be collected and interpreted.
• Research work on the chemical deblossoming may be strengthened.
• Research work on the role of malformin like substances. phenolic compounds. enzymatic activity. phytohormones needs to be strengthened and conclusion drawn.
• The mango grafts may be supplied after fumigating and treating With
• fungicides and only healthy plants may be transported from one place to another within the country and abroad.
• Role of the fungus and mites needs be evaluated seriously.
• A committee of the scientists from India and abroad. who are working on this project may be formed and the scientists may meet every year to review the progress.
• A multidisciplinary team consisting of Indian and foreign scientists may be constituted to implement the research programme.