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Epidemiology and Management of Turmeric (Curcuma longa L.) Leaf Spot [Colletotrichum gloeosporioides (Penz. and Sacc.)]

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Title Epidemiology and Management of Turmeric (Curcuma longa L.) Leaf Spot [Colletotrichum gloeosporioides (Penz. and Sacc.)]
 
Creator CHAWDA, SHEHULKUMAR K.
 
Contributor SABALPARA, A.N.
 
Subject dna, topping, vegetables, adp, physical control, humus, plant extracts, livestock
 
Description Turmeric (Curcuma longa L.) is one of the most
important spice crops. During the survey, occurrence of
leaf spot disease in turmeric (cv. Sugandham and Local)
was observed in serious proportion inflicting heavy losses
in south Gujarat. Considering the seriousness of the
disease, the present investigation was carried out on
various aspects to generate scientific information on this
important pathological problem and to develop suitable
management strategies to prevent the crop losses.
The pathogen involved to cause the leaf spot in
the area was identified as Colletotrichum gloeosporioides
earlier by Patel (2000) which was confirmed by
microscopic observations, study of symptomatology of the
disease, morphology and cultural characters of the
pathogen.
The pathogen found to be attacking upper leaves
of crop. The disease manifested in the form of elliptic or
oblong spots of variable size. In the initial stage, the spots
were pin head dot like in appearance. These spots
increased in size and coalesced to form large patches
involving major portion of the leaf. The centre of the spots
were grayish white with numerous black dots like acervuli
on both the surfaces. Sometime acervuli could be seen on
the midrib too. When the intensity of the disease was
severe, most of the leaves became yellowish, dried up and
the field presented a blighted appearance.
The leaf spot was found in severe proportion in
both the popular varieties viz., Sugandham and Local in
Navsari, Dangs, Surat and Tapi districts of south Gujarat.
Losses due to the leaf spot was estimated up to 31.70 per
cent.
Due to leaf spot of turmeric, losses were found
in all the growth parameters and ultimately affected in
reduction of rhizome weight (24.63%). However, curcumin
content was recorded to be increasing in diseased plants
as compared to healthy plants in different genotypes.
Phenol content was also recorded to be increasing due to
the disease. Genotypes resistant to leaf spot contained
higher amount of phenol as compared to the susceptible
one.
Non-reducing, reducing and total sugar content
was recorded to be lower in diseased leaves as compared
to the healthy leaves in all the genotypes.
Young crops (2 to 5 months) were mostly
remained free from the infection of the leaf spot. The
infection was started during August and attained its peak
on completion of major rainfall i.e. after 37th MSW. During
the major progress (37th to 40th MSW), average
temperature remained around 28 0C and 80 per cent
relative humidity with moderate rainfall.
Correlation coefficient study between weather
parameters and disease intensity indicated that all the
parameters jointly played an important role in the
development of disease. The multiple regression equation
[Ŷ = 77.39 + 1.04 (X1) – 3.69 (X2) – 0.0000000007 (X3) +
17.32 (X4) + 17.89 (X5) - 35.16 (X6) - 0.014 (X7) – 1.51 (X8)
where X1 = Maximum temperature, X2 = Minimum
temperature, X3 = Average temperature, X4 = Morning
relative humidity, X5 = Evening relative humidity, X6 =
Average relative humidity, X7 = Rainfall, X8 = Rainy days]
was developed for the forecasting (R=0.81).
Effect of lateral spacing and fertigation rate on
leaf spot revealed that the disease was not significantly
affected by lateral spacing but it was significantly affected
by different levels of fertigation during both the years.
Minimum disease intensity was recorded with full RDF
(22.00) followed by 80 per cent RDF fertigation (24.50).
Turmeric sown on the raised bed with 3 rows
and applied bio-compost @ 25 t/ha or bio-compost @ 12.5
t/ha + gypsum @ 2 t/ha proved better for the management
of leaf spot in turmeric as well as for getting higher
rhizome yield.
Amongst, 22 genotypes of turmeric screened
against leaf spot disease, the genotypes viz., NVST-1,
NVST-4, NVST-39, NVST-40 and NVST-50 showed
resistance reaction. Genotype NVST-2, NVST-5, NVST-34,
NVST-36, NVST-38, NVST-41, NVST-42, NVST-43, NVST45,
NVST-47, NVST-48 and NVST-49 showed moderately
resistant reaction. The rest of the varieties/genotypes
proved susceptible including Kesar and Sugandham.
The extract of Parthenium (Parthenium
hysterophorus L.), Garlic (Allium sativum L.) and Acacia
(Acacia nilotica L.) showed the strong inhibition of the
pathogen.
Among different isolates of Psuedomonas spp.
tested in pot condition, P. aeruginosa (PaWS) showed
maximum control (72.30%) of leaf spot followed by P.
aeruginosa (PaWP) and P. fluorescens (PfWN).
Among all the tested fungicides, carbendazim
(0.5 g/l) and propiconazole (1 ml/l) proved better for the
management of the disease as well as for getting higher
rhizome yield.
 
Date 2016-04-19T15:36:06Z
2016-04-19T15:36:06Z
2011-09
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/65489
 
Language en
 
Format application/pdf
 
Publisher Navsari Agricultural University, Navsari