Management of Alternaria alternata of blond Psyllium (Plantago ovata L.) through fungicides in vitro and natural condition

Abstract

The experiments were conducted at Department of Plant Pathology, S.K.N. College of Agriculture, Jobner (Rajasthan). Alternaria alternata was isolated from leaves of isabgol and observed to be pathogenic under artificial conditions. An attempt was more find out the efficacy of different fungicides were against in Alternaria alternata in vitro and in vivo condition. Among five fungicides mancozeb + carbendazim was found most effective against Alternaria alternata in vitro conditions followed by mancozeb and carbendazim. In potted plant minimum disease intensity were obtained in mancozeb + carbenxazim and mancozeb followed by carbendazim + difencozole. All treatments as foliar sprays were able to reduce disease severity over untreated control of 0.2% followed by 0.25% concentration. Carbendazim + mancozeb, and mancozeb were found effective in management of leaf blight of isabgol by Alternaria alternata in vitro and in vivo conditions.

Full text

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International Journal of Chemical Studies 2017; 5(3): 473-476
P-ISSN: 2349–8528
E-ISSN: 2321–4902
IJCS 2017; 5(3): 473-476
© 2017 JEZS
Received: 17-03-2017
Accepted: 18-04-2017
Sajjan Choudhary
Department of Plant Pathology,
S.K.N. College of Agriculture,
Jobner, Sknau, Jobner (Jaipur),
India
RP Ghasolia
Department of Plant Pathology,
SKNAU, Jobner, India
AL Yadav
Department of Plant Pathology,
S.K.N. College of Agriculture,
Jobner, Sknau, Jobner (Jaipur),
India
GL Kakraliya
Department of Plant Pathology,
S.K.N. College of Agriculture,
Jobner, Sknau, Jobner (Jaipur),
India
R Nasanwa
Department of Plant Pathology,
C.O.A. Bikaner, Skrau, Bikaner,
India
Correspondence
Sajjan Choudhary
Department of Plant Pathology,
S.K.N. College of Agriculture,
Jobner, Sknau, Jobner (Jaipur),
India
Management of Alternaria alternata of blond
Psyllium (Plantago ovata L.) through fungicides in
vitro and natural condition
Sajjan Choudhary, RP Ghasolia, AL Yadav, GL Kakraliya and R
Nasanwa
Abstract
The experiments were conducted at Department of Plant Pathology, S.K.N. College of Agriculture,
Jobner (Rajasthan). Alternaria alternata was isolated from leaves of isabgol and observed to be
pathogenic under artificial conditions. An attempt was more find out the efficacy of different fungicides
were against in Alternaria alternata in vitro and in vivo condition. Among five fungicides mancozeb +
carbendazim was found most effective against Alternaria alternata in vitro conditions followed by
mancozeb and carbendazim. In potted plant minimum disease intensity were obtained in mancozeb +
carbenxazim and mancozeb followed by carbendazim + difencozole. All treatments as foliar sprays were
able to reduce disease severity over untreated control of 0.2% followed by 0.25% concentration.
Carbendazim + mancozeb, and mancozeb were found effective in management of leaf blight of isabgol
by Alternaria alternata in vitro and in vivo conditions.
Keywords: Alternaria alternata, fungicide, leaf blight and plantago ovate, isabgol
1. Introduction
Blond psyllium (Plantago ovata Forsk.) commonly known as isabgol, is an annual herb with
narrow linear rosette like leaves belonging to the family Plantaginaceae. Isabgol is an
important cash crop cultivated for its export and being of important medicinal value is reported
to have larger demands and is traded in major medicinal markets of the world. Isabgol has
pharmaceutical importance to treat dysentery, chronic constipation and chronic diarrhoea and
as laxative demulcents, emollients and diuretics. India commands nearly monopoly in the
production and export of the seed and husk to the world market. India is earning about Rs.
1600 million as foreign exchange from the export of blond psyllium products to countries like
USA, Germany, France, England, Spain and Belgium [1].
In India, the isabgol crop is mainly grown as commercial crop in Gujarat, Rajasthan and
Madhya Pradesh. However, the crop is spreading to other non-traditional parts of the country
such as Haryana, Uttar Pradesh and Karnataka. In Rajasthan, it is being cultivated in 190081
hectares area with a total production of 99950 tonnes of seeds with an average productivity of
525 kg/ha [2]. In Rajasthan, lsabgol mainly cultivated in Barmer, Jalore, Nagaur, Jodhpur and
Jaisalmer districts. Presently, Rajasthan is on the top in productivity in India.
[3] reported a number of pathogens viz., Fusarium wilt (Fusarium oxysporum), damping off
(Pythium ultimum trow), leaf blight (Alternaria alternata (Fr.) Keissler), downy mildews
(Peronospora plantaginis) and powdery mildew (Erysiphe cichoracearum D.C.) affecting this
crop. Alternaria blight has become a serious problem in recent years. It has been found that
downy mildew affected crop is more prone to be attacked by A. alternata. It causes
considerable damage every year and sometimes become very severe which results in total loss
of yield [4]. Hence, present investigations were carried out to test the efficacy of plant extracts
and fungicides against leaf blight of isabgol incited by A. alternata.
2. Material and methods
Efficacy of different fungicides were evaluated against Alternaria alternata.
Efficacy of fungicides against Alternaria alternata (in vitro and in vivo)
The efficacy of five systemic and non-systemic fungicides against mycelial growth of
Alternaria alternata was tested by Poisoned Food Technique (PFT) suggested by [5].

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International Journal of Chemical Studies
Four different concentrations viz., 100, 300, 500 and 700 ppm
of each fungicide were tested in vitro. Required quantities of
each fungicides were added separately in to molten and
cooled PDA so as to get the desired concentration of the
fungicides later on 20 ml of poisoned medium was poured
sterilie petern plated mycelial rises of 5 mm size from gets
very growing culture of the fungus were cut by a sterlle cork
borer and one such rise was placed at the centre of each agar
plate then such plates were incubated 25 + 1 0C for 7 days and
radial growth was measured. The mycelial growth of the test
fungus was recorded and per cent growth inhibition was
calculated by [6] formula given below. The experiment was
conducted in completely randomized design with three
replications. C-T
Per cent growth inhibition = ------------------ x 100
C
Where,
C=Diameter of colony in check (Average of both diagonals)
T=Diameter of colony in treatment (Average of both
diagonals)
Efficacy of fungicides (in vivo):
The field experiments of the fungicides was conducted during
2013-14 in mini plots (1x1 m) of Department of Plant
Pathology, SKN COA, Jobner, Jaipur in RBD manner with
four replication plots during rabi season to know the efficacy
of fungicide against leaf blight of isabgol under natural
condition. All the recommended agronomic practices were
followed to raise the crop. The fungicides viz., thiophanate
methyl (0.2%), carbendazim *0.1%), mancozeb (0.25%),
carbendazim + mancozeb (0.2%) and difenoconazole (0.2%)
were tested by applying as foliar spray (40 DAS). The middle
two rows of each plot were rated for disease incidence (the
presence or absence of one or more lesions) at 60 DAS by
examining five leaves from five adjacent plants at 5 random
sites within each plot for a total of 25 leaves per plot. The per
cent disease intensity (PDI) was assessed for each plot on a
disease rating scale of 1-9 [7] based on the percentage of leaf
area symptomatic (1= 0% tissue symptomatic, 2= up to 1%,
3= 2-5%, 4= 6-10%, 5= 11-20%, 6= 21-30%, 7= 31-40%, 8=
41-50%, and 9= over 50%). The intensity was calculated by
using the formula of [8].
Sum of individual ratings
PDI = x 100
Number of leaves observed x Maximum disease rating
The per cent disease control was calculated by using the
following formula:
Disease in control – Disease in treatment
PDC = x 100
Disease in control
3. Result and discussion
Efficacy of fungicides in vitro
The data (table 1) suggested that increase in concentrations of
the fungicides caused increased inhibition of mycelial growth
of the fungus. Among five fungicides tested,
carbendazim+mancozeb (Companion) was found most
effective which was showing 66.66, 79.99, 87.77 and 94.44
per cent inhibition of mycelial growth of Alternaria alternata
at 100, 300, 500 and 700 ppm concentrations, respectively
followed by mancozeb (48.88, 71.11, 83.33 and 87.77,
respectively). Thiophanate methyl was found to be least
effective in inhibiting mycelial growth. This experiment
shows that carbendazim+mancozeb is highly effective in
inhibiting the mycelial growth of Alternaria alternata in vitro.
Similar observations were observed by earlier worker [9].
Efficacy of fungicides in reducing disease intensity (in
vivo)
On the basis of performance of fungicide in vitro all five
fungicdies viz. mancozeb, carbendizim+mancazeb,
thiophanate methyl and difenoconazole each of 0.25, 0.2 and
0.2 per cent were evaluated in field conditions through foliar
sprays against blight disease of isabgol. The results (Table 2)
revealed that there was clear reduction disease in intensity
when fungicides were applied as foliar spray maximum per
cent efficacy of disease control was observed at 0.2 % (31.07
per cent) foliar spray of carbenxazim + mancozeb) which was
followed by foliar spray of mancozeb 0.25% (20.71 per cent)
carbenxazim 0.1% (19.93 per cent) difenconazole 0.25%
(13.94 per cent) and thiophonate 0.1% (11.95 per cent)
efficacy of disease control respectively.
These studied will be helpful in controlling the blight
incidence in the field effectively. Present results are in
accordance with [10, 11, 9, 12].
Similar results were obtained by [12, 9, 13].
Table 1: Comparative efficiacy of different fungicides on mycelial growth of Alternaria alternata in vitro after 7 days of incubation at 25 + 1 0C
Fungicides
Per cent growth inhibition at various concentration (ppm)*
Mean
100
300
500
700
Mancozeb
48.88 (44.36)
71.11 (57.49)
83.33 (65.90)
87.77 (69.53)
73.33 (59.32)
Carbendazim
42.22 (40.52)
48.88 (44.36)
54.44 (47.55)
60.00 (50.77)
51.39 (45.80)
Thiophanate methyl
19.00 (25.84)
42.22 (40.52)
51.11 (45.64)
65.00 (53.73)
44.71 (41.43)
Carbendazim+mancozeb
66.66 (54.73)
79.99 (63.43)
87.77 (69.53)
94.44 (76.36)
82.21 (66.01)
Difenoconazole
40.00 (39.23)
44.44 (41.81)
51.11 (45.64)
70.00 (56.79)
49.72 (45.86)
Check
0.00
0.00
0.00
0.00
0.00
SEm+
CD (p=0.05)
F
0.60
1.72
C
0.49
1.40
FxC
1.21
3.44
* Average of 4 replications
Figures given in parentheses are angular transformed values

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International Journal of Chemical Studies
Table 2: Effect of fungicidal foliar spray on disease intensity (in vivo)
S. No.
Fungicides
Dose (%)
Per cent disease intensity*
Per cent disease intensity reduction over control
1
Carbendazim+ mancozeb
0.2
43.25 (41.12)
31.07
2
Mancozeb
0.25
49.75 (44.86)
20.71
3
Carbendazim
0.1
52.75 (46.58)
19.93
4
Thiophanate methyl
0.2
55.25 (47.29)
11.95
5
Difenoconazole
0.2
54.25 (47.44)
13.94
6
Control
-
62.75 (52.39)
-
SEm+
1.44
CD (p=0.05)
4.21
Figures given in parentheses are angular transformed values
* Average of four replications

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International Journal of Chemical Studies
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