mango malformation
TRANSCRIPT
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Mango malformation
Ningappa Kirasur2014-12-129Dept. of Olericulture COH, Vellanikkara
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Mango
o Mangifera indica L.
o Anacardaceae
o 2n=4x=40
o South East Asia
o Occupies a pre-eminent place among fruit crops in India
o It is ‘King of fruits’ in the country
o Malformation is the most threatening malady
o Causes 50-80% yield loss
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Mango Malformation
o Fusarium moniliforme var. subglutinans
o It was first reported by Watt in 1891 Darbhanga district of Bihar
Types of malformation
o Vegetative Malformation
o Floral Malformation
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Vegetative Malformation
o Is more commonly found on young seedlings
o It is characterised by disrupting of apical growth
resulting in several small flushes
o Quite short internodes at the apical ends of various
branches
o These shoots bear small leafy structures
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Contd…
o The multi-branching of shoot apex with scaly leaves
is known as “Bunchy Top” or “Witche’s Broom”
o The malformed seedlings, becomes remain stunted
and die
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Symptoms of Vegetative malformation
Contd…
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Floral Malformation
o The primary, secondary and tertiary rachises become short, thickened and hypertrophied
o Such panicles are greener and heavier with increased crowded branches
o These panicles have numerous flowers that remain unopened and are predominantly male flowers
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Symptoms of floral malformation
Contd…
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Cultivar susceptibility
o The susceptibility to malformation in mango varieties is
variable
o Is governed by the different factors like temperature, age of
the tree, time
o Amrapalli was found highly susceptible to mango
malformation
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Contd…
o The 60% diseased panicles in cv. Neelum during the flowering of February-March
o whereas the same plant had only 4-5% malformation during off season flowering in June
o Incidence of disease is more in young plants than in older ones
o About 91% incidence in 4-8 years plants 9.6% in older plants was reported
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Abiotic factors
Temperature:o The low temperature at the time of flowering was
correlated with the intensity of malformationo The incidence of disease is most severe in north-
west region of Indiao where mean temperature during flowering remains
between 10-15°C o It is mild where corresponding temperature is
15-20°C, sporadic at 20-25°C
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Nutritional aspects
Micronutrient:
o The micronutrient deficiency, particularly iron and
zinc and copper has been associated with the cause
of malformation
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Ethylene
As some of the symptoms of mango malformation
resemble with those of ethylene effects
The role for ethylene in mango malformation
Significantly higher level
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Other Factors
Malformin:
o The presence of malformin- like substances in fully
grown malformed panicles has been reported
o The stem and root of malformed vegetative seedlings
contain higher level of malformin as compared to
healthy seedlings
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Mangiferin
o Mangiferin is either absent or present. only in traces
in healthy mango panicles but in malformed ones
contains higher concentration
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MANAGEMENT
Plant Growth regulators:
o The application of NAA 100-200 ppm, at flower bud
differentiation stage reduce the malformation
o Spraying of 500 ppm ethrel in February was highly
effective in reducing floral malformation
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Contd…
o Spraying 1000 ppm placlobutrazol prior to FBD,
during the first week of October
o GA3 @ 30ppm reduced incidence of malformation
when sprayed at pre bloom stage
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Deblossoming
o Deblossoming at bud burst stage, spraying of 200
ppm NAA was reported to be very effective in
controlling malformation
o Application of cyclohexamide at 250 ppm was very
effective in deblossoming the panicles
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Pruning
o Prune the malformed branches
o Pruning followed by spraying with the mixture of
fungicide (Captan 0.1%), helps in controlling the
spread of the disease
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Insecticides and fungicides
o Pruning followed by a spray of insecticides follidol or
metasystox as a control measure was recommended
o The control of malformation with spray of
Carbendazim 0.1% at 10, 15 and 30 days interval (Oct.
to Feb.) during the flower bud differentiation stage
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Management through bio-pesticides
o Trichoderma viridae, T. virens and
T. harzianum were used against the malformation
o The best result was obtained from Trichoderma
harzianum followed by T. virens and T. viridae
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Thank you