1 Project Report On Studies on the use of Plant Activator and Silicon nutrient for the management of Powdery mildew of Black gram (Vigna mungo L. Hepper) Submitted by S.Parthasarathy, Reg. No. 08281 Final B.Sc. (Agri.) Department of Plant Pathology Faculty of Agriculture Annamalai University Annamalai nagar – 608 002.
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1
Project Report On
Studies on the use of Plant Activator and Silicon nutrient for the management of Powdery mildew of Black gram (Vigna mungo L. Hepper)
Submitted by
S.Parthasarathy, Reg. No. 08281 Final B.Sc. (Agri.)
Department of Plant Pathology
Faculty of Agriculture
Annamalai University
Annamalai nagar – 608 002.
2
ANNAMALAI UNIVERSITY FACULTY OF AGRICULTURE
DEPARTMENT OF PLANT PATHOLOGY
RES 423 – RESEARCH PROJECT
CERTIFICATE
IV B.Sc.(Agri.) 2011-2012 Final Semester
Certified that Selvan S.Parthasarathy,Reg.No.08281 of IV B.Sc. (Agri.) class has duly completed and submitted a research project entitled “Studies on the use of plant activator and silicon nutrient for the management of Powdery mildew of Black gram (Vigna mungo L. Hepper) ” under my supervision during the final semester of 2011-2012.
Date : Examiners Guide
Place:
3
Acknowledgement
4
ACKNOWLEDGEMENT
Above all, I submit my thoughts and actions to the Almighty who always guides me in the path of righteousness and whose blessings have enabled me to complete this work successfully.
I have immense pleasure in placing in record my indebtedness and profound sense of gratitude to my guide Dr.V.Jaiganesh, Assistant Professor (Plant Pathology), Faculty of Agriculture, Annamalai University for suggesting this project and for his keen interest, constant encouragement, precise guidance, and constructive criticisms throughout the tenure of this study and the preparation of this dissertation.
I wish to express my heartful thanks to Dr. V. Kurucheve, Ph.D., Professor and Head, Department of Plant Pathology for his generous encouragement during my course of study.
I proudly record my sincere thanks to Dr. RM. Kathiresan, Ph.D.,D.Sc., Dean, Faculty of Agriculture, Annamalai University for allotting my project work in the Department of Plant Pathology and his guidance.
I convey my special thanks to Dr .L.D.C. Henry, and also each and every staff of department of Plant pathology.
On a personal note, I also express my special thanks to Dr.C.Kannan for his immense help during crucial times of need.
With abundance of my heart, I express my affectionate gratitude to my Parents Mr. P.Seethapathy and Mrs. S.Gandhimathi who always stand beside me with moral support and fathomless love in every step of my life.
Place: Annamalai Nagar (S.PATHASARATHY)
Date:
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CONTENTS
Chapter No.
Title
Page No.
1.
2.
3.
4.
5.
6.
7.
8.
Introduction
Review of literature
Materials and Methods
Experimental Results
Discussion
Summary
References
7
12
23
28
37
39
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Introduction
7
INTRODUCTION
Pulses have been cultivated as protein sources, under low input
agriculture for thousands of years. Pulses constitute the main sources of
essential protein and for predominantly vegetarian population of India.
Among these black gram or urd bean (Vigna mungo L. Hepper) is pulse crop
of many Asian countries and it belongs to tribe phaseolus family
leguminoseae with chromosome number 2n=22. Urd is said to have
originated in India when it is most widely grown and highly esteemed grain
legume (Chatterjee and Bhattacharya, 1986). Black gram attracts high price
among all pulses and it is highly rich in phosphoric acid. It is more often
used for preparing pappad which is a very popular side dish with any kind
of meal, routine or special. Urd bean occupies about 14 per cent of the total
area under pulse in the country and ranks fourth in area and production
after chickpea, pigeonpea and mungbean.
In India alone it occupies about 3.17 million hectare and annual
production of urd bean in India is about 1.33 million tonnes. Urd is highly
prized pulse and cultivated under a wide range of predominantly rain fed
farming system in dry and intermediate agro ecological zones on marginal
lands with low moisture and fertility conditions. Besides it is a important
protein source for people in the cereal-based society because it is rich in
phosphoric acid among pulses, rich in source of vegetable protein (20- 25%)
with some essential minerals and vitamins for the human body.
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Pulses has been under cultivation from time immemorial, being grown
under varying climatic conditions in different parts of the country. It is
widely affected by quite a number of diseases caused by fungi, bacteria,
viruses and mycoplasma which results in higher yield losses (Rangaswami
and Mahadevan, 2005).
Among the fungal diseases, powdery mildew incited by
Erysiphe polygoni DC is a major disease occurring in almost all the black
gram growing areas of the world and is the most destructive fungal disease
of black gram causing yield loss up to 20-40 per cent (Reddy et al., 1994)
despite decades of research towards its management.
The management of powdery mildew disease is done by using
The statistical analysis of the experimental results was performed employing the
computer software package ‘IRRISTAT’, version 90-1, developed by Department of
Statistics, International Rice Research Institute, Philippines and as per the procedure of
Gomez and Gomez (1976).
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Field trail Pod formation stage
First spraying
28
Salicylic acid treated plants
Medium Preparation
Powdery mildew – Grade 9
Phytotoxicity symptoms
29
Results and discussion
30
Results and Discussion
Evaluation of Silicon based nutrients against powdery mildew of black gram
(Pot culture experiment)
The results of pot culture experiments showed that all the silicon based nutrients
reduced the powdery mildew disease incidence over control. Among them, sodium
silicate at one per cent level was the most effective (7.21 %) over the other nutrients
followed by potassium silicate at one per cent in reducing disease incidence (9.52 %) as
compared to 32.40per cent observed in control. Calcium silicate at 0.25 per cent was the
least effective (Table 1).
In general, yield was significantly higher in silicon nutrient treated plots when
compared to test fungicide Mancozeb treated and control plots. Sodium silicate at 1 per
cent level recorded maximum black gram pod yield, followed by sodium silicate @ 0.50
per cent level. There is no significant difference in hundred gram yield among the
treatments. Also, phytotoxicity symptoms observed in potassium and calcium silicate
treated plants.
In the present study the results of pot culture experiments also showed that all
the silicon based nutrients reduced the disease incidence over control (Table 1). The
yield was significantly higher in silicon nutrient treated plots when compared to test
fungicie treated and control plots. Sodium silicate at one per cent level recorded
maximum grain yield and minimum disease incidence.
31
Silicon is considered as a beneficial nutrient element in plant biology (Anser, 2009).
It is incontestably an essential requirement for the normal growth of many plants and must be
called as “Quasi essential” (Epstein, 1999). Rice is a best silicon accumulator and its uptake
is about twice that of nitrogen (Savant et al., 1997). Wagner (1940) first reported that Si
application effectively reduced powdery mildew in cucumber.
A review by Epstein (1999), discussed the role of silicon on plant disease control.
Foliar application of soluble Si reduced the powdery mildew severity in cucumber (Lee et al.,
2000), common beans (Rodrigues et al., 2005a) and soybeans (Rodrigues et al., 2005b).
Potassium silicate applications have resulted in reduced severities of powdery mildew on
grape (Yildirim et al., 2002) and strawberry (Kanto et al., 2006). Foliar application of
potassium silicate, as a source of soluble silicon, decreased angular leaf spot severity on
beans (Rodrigues et al., 2005a). Calcium silicate was effective in the reduction of Frog eye
spot, downy mildew and Asian rust in soybean (Nolla et al., 2006) and anthracnose in beans
(Moraes et al., 2009).
A possible effect of foliar application of Si sources on diseases control might be
explained by the establishment of a physical barrier on the host tissue (Bowen et al., 1992).
Silicates act as a bioactive element and are associated with beneficial effects on the
mechanical and physiological properties of plants (Epstein, 2001).
Rodrigues et al. (2004) reported that plant’s defense mechanisms have been triggered
by silicon. Liquid potassium silicate may play a role not only as a physical barrier, but also as
resistance inducer in plants (Ghanmi et al., 2004). Si application might not yield a direct
measurable effect on crop growth, but its positive role on disease suppression may lead to
better plant productivity (Guevel et al., 2007).
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Thus, increased plant resistance to diseases through Si treatment is associated with
active and/or passive mechanisms (Datnoff et al., 2007).
Several studies have demonstrated that the severity of foliar diseases of various crops
including cereals and pulses can be reduced through foliar or soil applications of potassium
silicate (Rodrigues et al., 2005a; Moraes et al., 2006; Guevel et al., 2007; Buck et al., 2008;
Dallagnol et al., 2009).
Rodrigues et al. (2003) stated that silicon fertilization to rice crop reduced the
incidence of sheath blight. Martinati et al. (2008) proved that potassium silicate treated coffee
plants improved the production, productivity and increased the resistance against coffee rust
caused by Hemileia vastatrix.
Rezende et al. (2009) proved that root and foliar application of potassium silicate can
decrease the intensity of brown spot of rice. Rodrigues et al. (2010) mentioned that bean
plants treated with potassium silicate induced defense mechanism and reduced the severity of
angular leaf spot of beans caused by Pseudocerspora griseola.
The ability of soluble silicon (Si) to reduce the impact of plant diseases has been
sufficiently described in rice and various crops (Belanger et al., 1995; Fawe et al., 2001;
Rodrigues et al., 2003; Kim et al., 2002). Liang et al., (2005) suggested that disease reduction
caused by foliar sprays of potassium silicate was the result of an osmotic effect on spores
germinating at the leaf surface.
It has been reported that potassium fertilizer application can decrease brown spot
severity on rice (Carvalho et al., 2010). The brown spot disease of rice is usually associated
with an imbalance of K (potassium) and N (nitrogen) in rice leaf tissue and K is able to
reduce disease intensity (Baba et al., 1958). The potassium content in potassium silicate
could have also contributed to the enhanced disease suppression. Further, silicon, in the form
33
of silicic acid, would act locally by inducing defense reactions in elicited cells and would also
contribute to systemic resistance by enhancing the production of stress hormones (Fauteux et
al., 2005). Thus, the above reasons could be attributed for the efficacy of foliar sprays of
silicon fertilizers, in reducing the powdery mildew incidence of rice.
Table 2. Evaluation of certain plant activators against powdery mildew of black gram
(Pot culture experiment)
Among the various resistance inducing chemicals, salicylic acid @ 50 ppm was
the most effective (5.30 %) in reducing the powdery mildew incidence followed by
plots sprayed with Acetyl Salicylic acid @ 50 ppm level (7.55 %). It was followed by
Nicotinic acid & Benzoic acid (1000 ppm). Benzoic acid at 10 ppm was least effective.
The test fungicide, Mancozeb was also found to be effective (12.15 %) in reducing the
powdery mildew incidence as against control (34.20 %) (Table 2).
In general, yield was significantly higher in all plant activator treated plots when
compared to test fungicide Mancozeb treated and control plots. Salicylic acid at 50 ppm
level recorded maximum black gram pod yield. There is no significant difference in
hundred gram yield among the treatments. Also, phytotoxicity symptoms observed in all
the chemical inducer treated plants except Salicylic acid.
All the resistance inducing chemicals were found effective in reducing the brown
spot incidence and enhancing the yield when compared to control in pot culture as well
as field studies (Table 8 and Table 12). Among the various resistance inducing
chemicals, salicylic acid (SA) was found as the most effective when compared to other
resistance inducing chemicals.
NAA has been reported to reduce Fusarium wilt of tomato (Corden and Dimond,
1959) and Verticillium wilt of potato (Corsini et al., 1989) through induction of host
34
resistance. Colson et al. (2000) reported that, Bion 50 WG reduced the incidence of
Alternaria microspora on cotton. 2,4-D was found effective against root rot of peanuts
caused by Pythium myriotylum through their effect on root lipids and root lipid
exudation patterns (Hale et al., 1981). Bokshi et al. (2006) indicated that INA increased
chitinase and peroxidase activities and reduced powdery mildew and downy mildew on
leaves of melons. Acibenzolar-S-methyl was effective against blue mould caused by
Peronospora tabacina (Perez et al., 2003; LaMondia, 2009). Foliar application of ASM at
pre flowering period to manage the post harvest rots of rock melon and Hami melons
(Huang et al., 2000) has also been reported. Likewise, the chemical inducer, 2,6-
dichloroisonicotinic acid provided good levels of protection against pear fire blight
(Kessmann et al., 1994) and against apple scab (Ortega et al., 1998). Vechet et al. (2009)
observed that foliar application of salicylic acid increased the resistance in wheat plants
against powdery mildew pathogen. The present findings on the efficacy of resistance
inducing chemicals are also in line with these earlier reports.
Further, resistance inducers when applied exogenously induced the expression of PR
(pathogenesis related) genes, increased the growth characters and also conferred resistance
against various pathogens of viral, bacterial and fungal origin in monocot plants (Morris et
al., 1998; Pasquer et al., 2005; Makandar et al., 2006). Thus, induced resistance may provide
an alternative approach to plant protection especially for problems not satisfactorily
controlled by fungicides (Schoenbeck 1996).
Foliar application of the resistance inducing chemicals at low conc. along with their
non-hazardous nature, simple application procedure, systemic effect and low cost marks this
approach as an effective, feasible and an eco-friendly alternative to conventional chemical
management (Eswaran et al., 2011).
35
Salicylic acid (SA) is a plant-derived compound induced resistance against pathogens
and stimulated plant growth (Nickell, 1983; Vidhyasekaran, 1990). It was also reported that
SA plays an important role in plant defense by the development of SAR against pathogens
(Ryals et al., 1994). SA has been shown to be a signalling molecule involved in both
local defence reactions at infection sites and the induction of systemic resistance
(Durner et al., 1997). SA is a phenolic compound present in many plants and is an
important component in the signal transduction pathway involved in local and systemic
resistance to pathogens (Frey and Carver, 1998).
The findings of Percival et al. (2009) lends support to the present observations on
the use of SA who proved that salicylic acid sprayed at different growth stages in apple and
pear increased the resistance against scab. The use of SA at low conc. is taken up more easily
into crop plants than higher conc. Sometimes, higher conc. of SA treated plants are killed
(Frey and Carver, 1998). In the present study also SA was found very effective at 50 ppm
conc. In this respect, chemicals like salicylic acid may especially be suitably used as inducers
of disease resistance.
Changes in Carbohydrates
Reducing sugars
From the results depicted in table 3, a general reduction was observed in the
quantity of reducing sugars due to treatment with Salicylic acid and Sodium silicate.
Also, decreasing levels of reducing sugar content was observed with increase in time. In
inoculated plants the level of reducing sugar was higher than in control.
36
Non-reducing sugars
Spray with Salicylic acid and Sodium silicate significantly influenced the non-
reducing sugars content when compared to control. In inoculated plants, the non-
reducing sugar content was more in control on 21st day of sampling. The non-reducing
sugars content decreased as the sampling periods increased.
Total sugars
Similar to the trend observed in reducing and non-reducing sugar content, the
treatments with Salicylic acid and Sodium silicate reduced the total sugar content when
compared to control. Maximum total sugar was recorded in control (32.54 mg/g). An
increase in sampling period gradually decreased the total sugar content in all the
treatments (Table 3).
Carbohydrates are the basic building blocks for the synthesis of various defense
chemicals such as phenolics, phytoalexins and lignin. Hence, the quality and quantity of
sugars play an important role in disease resistance (Vidhyasekaran and Kandasamy, 1972;
Vidhyasekaran, 1974). Altering the sugar content of leaves has been shown to be a possible
way to control diseases (Sondeep singh et al., 2009) and interfering with the physiology of
the host could potentially offer an exciting opportunity to control diseases.
Pathogen infection leading to decreased sugar contents has been reported in
sweet corn (Levy and Cohen, 1984). Kalim et al. (2003) reported significant decrease in the
quantity of total soluble sugars in zinc and manganese treated roots of plants inoculated with
Rhizoctonia solani and R. bataticola. The reducing, non and total sugar content were
decreased with increasing conc. of resistance inducing chemicals in H. oryzae infected plants
37
(Vengadesh Kumar, 2005). The exogenous SA application enhanced the carbohydrate content
in maize (Khodary, 2004). Reduction of sugars and accumulation of starch due to the
application of combination of lignite fly ash with potash in blast infected leaves was
reported by Mallika and Ramabadran (1995) and Karpagavalli (1999). These reports
lend support to the present findings.
38
Table 1. Evaluation of Silicon based nutrients against powdery mildew of black gram (Pot culture experiment)
Sl.No. silicon nutrients Disease incidence (%)
Yield (as Kg/ha level)
Hundred black grams weight
(gms)
Phytotoxicity symptoms observed
1. Potassium silicate
0.50 % 13.65 1075 4.2 ---
0.75 % 12.29 1123 4.3 ---
1.0 % 09.52 1216 4.5 observed
2. Calcium silicate 0.50 % 15.47 1081 4.1 ---
0.75 % 13.84 1137 4.2 ---
1.0 % 11.02 1205 4.3 observed
3. Sodium silicate 0.50 % 12.80 1198 4.6 ---
0.75 % 09.92 1306 4.6 ---
1.0 % 07.21 1482 4.8 ---
4. Mancozeb 0.1 % 10.98 1100 4.3 ---
5. Control 32.40 920 4.0
C.D. (p=0.05) 0.243 -- --
39
Table 2. Evaluation of certain plant activators against powdery mildew of black gram (Pot culture experiment)
Sl.No. silicon nutrients Disease incidence
(%)
Yield Hundred black
grams weight
Phytotoxicity
symptoms
observed
1. Acetyl Salicylic
acid
10 ppm 11.79 1222 4.2 ---
20 ppm 09.23 1337 4.3 ---
50 ppm 07.55 1429 4.5 observed
2. Nicotinic acid 10 ppm 14.73 1100 4.3 ---
20 ppm 12.96 1258 4.5 ---
50 ppm 10.08 1330 4.6 observed
3. Salicylic acid 10 ppm 09.83 1285 4.6 ---
20 ppm 07.98 1438 4.8 ---
50 ppm 05.30 1518 5.0 ---
4. Propionic acid 10 ppm 16.72 1092 4.3 observed
20 ppm 14.96 1168 4.4 observed
50 ppm 12.86 1290 4.6 observed
5. Benzoic acid 10 ppm 20.02 1088 4.3 ---
20 ppm 17.95 1143 4.3 ---
50 ppm 15.08 1256 4.4 observed
6. Mancozeb 0.1 % 12.15 1088 4.3 ---
7. Control 34.20 958 4.0 ---
C.D. (p=0.05) 0.371 --- --
40
Table. 3.
Studies on the changes of biochemical parameters in black gram plants due to the treatment with Salicylic acid and potassium silicate application (on 21st day of observation)
Sl.No. silicon nutrients Reducing sugars (mg/g)
Non reducing sugars (mg/g)
Total sugars (mg/g)
1.
Salicylic acid
10 ppm 27.56 04.29 30.79
20 ppm 27.08 04.23 30.47
50 ppm 25.43 04.16 30.08
2.
Sodium silicate
0.25 % 28.05 04.31 31.19
0.50 % 27.24 04.26 30.94
1.0 % 26.72 04.20 30.56
3. Control 28.76 04.38 32.54
41
Summary
42
Summary
The present study was undertaken to investigate the effect of application of chemical
inducers and silicon based nutrient for the successful management of black gram powdery
mildew disease incidence.
Among the various silicon based nutrients Sodium Silicate @ 1 per cent recorded the
minimum disease incidence and maximum yield.
Among the various plant activators Salicylic acid @ 50 ppm recorded the minimum
disease incidence and maximum yield.
The phytotoxicity symptoms observed in potassium silicate, Calcium silicate, Acetyl
salicylic acid, Nicotinic acid and Benzoic acid at various concentrations in black gram
plants.
43
References
44
Selected References
Abo-Elyousr, K. A. M. , Hussein, M. A. M. , Allam, A. D. A. and Hassan, M. H. (2009). Salicylic
acid induced systemic resistance on onion plants against Stemphylium vesicarium. Archives of
Phytopathol. And Plant Protection, 42: 1042 -1050.
Abreu, M.E. and Munne-Bosch, S. (2009). Salicylic acid deficiency in NahG transgenic lines and
sid2 mutants increases seed yield in the annual plant Arabidopsis thaliana. Journal of
Experimental Botany, 60: 1261-1271.
Achuo, E.A., Audenaert, K., Meziane, H. and Hofte, M. (2004). The salicylic acid-dependant
defense pathway is effective against different pathogens in tomato and tobacco. Plant Pathol.,
53: 63–72.
Anderson, M.D., Chen, Z. and Klessig, D.F. (1998). Possible involvement of lipid peroxidation in
salicylic acid-mediated induction of PR1 gene expression. Phytochemistry, 47: 555–566.
Aziz, T., Gill, M. A. and Rahmatullah, R. (2002). Silicon nutrition and crop production: A review.
Pak. J. Agric. Sci., 39 (3):181-187.
Baysal, O., Gursoy, Y.Z., Ornek, H. and Duru, A. (2005). Induction of oxidants in tomato leaves
treated with DL - Beta-aminobutyric acid (BABA) infected with Clavibacter michiganensis
ssp. michiganensis. Eur. J. Plant. Pathol., 112: 361-369.
Becot, S., Pajot, E., Corre, D.L., Monot, C. and Silue, D. (2000). Phytogard (K2HPO3) induces
localized resistance in cauliflower to downy mildew of crucifers. Crop Protection, 19: 417-
425.
Belanger, R. R., Bowen, P. A., Ehret, D. L. and Menzies, J. G. (1995). Soluble silicon: its role in
crop and disease management of greenhouse crops. Plant Dis., 79: 329–336.
Belanger, R.R., Benhamou, N. and Menzies, J.G. (2003). Cytological evidence of an active role of
silicon in wheat resistance to powdery mildew (Blumeria graminis f.sp. tritici). Phytopathol.,
93: 402–412.
45
Bengtsson, M., Wulff, E., Jorgensen, H.J.L., Pham, A., Lubeck, M. and Hockenhull, J. (2008).
Comparative studies on the effects of a yucca extract and Acibenzolar -S- Methyl on
inhibition of Venturia inaequalis in apple leaves. European J. of Pl. Pathol.,114: 512-518