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EFFECT OF SOME BIOLOGICAL CONTROL AGENTS IN REDUCING THE DISEASE INCIDENCE AND SEVERITY OF WHITE MOLD DISEASE ON EGGPLANT CAUSED BY SCLEROTINIA SCLEROTIORUM

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The study aimed to isolating and diagnosing the pathogen of white mold on eggplant and evaluating the efficiency of some plant extracts and biological agents against pathogens under field conditions. The results of isolation and diagnosis showed three isolates of Sclerotinia sclerotiorum. The results of the field experiment showed that all the treatment used in the experiment, which included P. fluorescens, Effective Microorganism EM-1 and the Water hyacinth extract, reduced the negative effects of S. sclerotiorum and clearly protected eggplant plants from white mold disease. Resulted in a significant reduction in the percentage of infection and the severity of infection and in different rates compared with the treatment of S. sclerotiorum disease alone, which had a treatment rate of 100% and severity of infection 56.67%, where the treatment of integration between the biological product EM-1 and P. fluorescens and Aqueous extract of Water hyacinth in the reduction of infection rate, amounting to 16.67% and the severity of the injury 10.00%. Which was positively reflected in the increase in the rate of plant height, wet and dry weight of eggplant plants and the superiority of the treatment of interference between the extract of Water hyacinth and bacteria. P. fluorescens and EM-1 increased plant rate of 152.00 cm and wet dry weight 626.67 and 160.42 g, respectively. The total increase of eggplant was 29.96 kg compared with S. sclerotiorum, which gave a weight of 11.77 kg.
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Plant Archives
Vol. 19, Supplement 2, 2019 pp. 646-652 e-ISSN:2581-6063 (online), ISSN:0972-5210
EFFECT OF SOME BIOLOGICAL CONTROL AGENTS IN REDUCING THE DISEASE
INCIDENCE AND SEVERITY OF WHITE MOLD DISEASE ON EGGPLANT CAUSED
BY SCLEROTINIA SCLEROTIORUM
Samah K.M. Al-Tameemi and Ahed Abd Ali Hadi Matloob
Al-Mussaib Technical College, University of Al-Furat Al-Awsat Technical, 51009, Babylon, Iraq.
Corresponding author: ahad_20071980@yahoo.com Mob.07805378490
Abstract
The study aimed to isolating and diagnosing the pathogen of white mold on eggplant and evaluating the efficiency of some plant extracts and
biological agents against pathogens under field conditions. The results of isolation and diagnosis showed three isolates of Sclerotinia
sclerotiorum. The results of the field experiment showed that all the treatment used in the experiment, which included P. fluorescens,
Effective Microorganism EM-1 and the Water hyacinth extract, reduced the negative effects of S. sclerotiorum and clearly protected
eggplant plants from white mold disease. Resulted in a significant reduction in the percentage of infection and the severity of infection and
in different rates compared with the treatment of S. sclerotiorum disease alone, which had a treatment rate of 100% and severity of infection
56.67%, where the treatment of integration between the biological product EM-1 and P. fluorescens and Aqueous extract of Water hyacinth
in the reduction of infection rate, amounting to 16.67% and the severity of the injury 10.00%. Which was positively reflected in the increase
in the rate of plant height, wet and dry weight of eggplant plants and the superiority of the treatment of interference between the extract of
Water hyacinth and bacteria. P. fluorescens and EM-1 increased plant rate of 152.00 cm and wet dry weight 626.67 and 160.42 g,
respectively. The total increase of eggplant was 29.96 kg compared with S. sclerotiorum, which gave a weight of 11.77 kg.
Keywords: Eggplant, white mold, Sclerotinia sclerotiorum, Effective Microorganism, Plant extracts.
Introduction
Eggplant. Solanum melongena L is strongly affected by
the white mold disease caused by Sclerotinia sclerotiorum
Bary de (Lib), especially in greenhouses, that attacks the
vegetative and causes significant losses of many crops
(Barros et al., 2015). Despite the use of specialized
fungicides to control it, the efforts of researchers in plant
protection have focused recently on the search for less
dangerous and safer ways to the environment and human
health and an alternative to the use of chemical pesticides
(Nutsugah et al., 2004; Siddiqui and Shaukat, 2003;
Rothmann and McLaren, 2018; Smolińska and Kowalska,
2018). The microorganisms that inhibit plant pathogens are
also used to increase production. These organisms are a
group of bacteria called plant growth promoters
Rhizobacteria (Pseudomonas, Bacillus, etc.) Increase plant
growth due to nitrogen, nutrient uptake in soil solution, effect
on root growth, ability to resist or reduce the effect of
pathogens, formation of Siderophores and some enzymes
such as Chitinase and other compounds such as antigens And
the ability to build or change the concentration of growth
regulators and the ability of bacteria to build the enzyme
ACC deaminase, which reduces the concentration of ethylene
and then stimulate growth. The bacteria build B-1-3-
glucanase enzyme and improve the absorption of nutrients
and accelerate the start of stress resistance (Ding et al., 2001;
Al-whaib, 2006; Tozlu et al., 2016; Hernández-Salmerón et
al., 2017; Manasa et al., 2017; Joshi et al., 2018). Previous
studies have demonstrated the efficacy of the effective
Micro-Organisms (EM-1) against bacterial and fungal
pathogens due to the fact that it contains microbiological
organisms that compete with the pathogen and produce
secondary metabolites, antifungal substances and growth
regulators that help to improve growth. (Nira, 2012; Nia,
2015). Researchers are increasingly interested in using plant
extracts to control many pathogenic pathogens of plants
because they contain these extracts from Merck It is an
effective secondary metabolite with desirable properties in
the environment such as rapid degradation, high
specialization and low toxicity of the organism (Lokendra
and Sharma, 1978). Because of the importance of white mold
disease on eggplant and to try to control it with using some
plant extracts and biological control agent, the study aimed to
isolate and diagnose the cause of white mold on eggplant.
And evaluation of the efficiency of some plant extracts and
biological control agent against the cause of white mold
disease on eggplant.
Materials and Methods
Isolation and diagnosis of Sclerotinia sclerotiorum
Isolation of S. sclerotiorum from the samples of
eggplant plants infected with white mold disease collected
from the agricultural areas in the province of Babylon/district
Mahaweel (Abu Jassim, Al-Badaa and Mussaib), parts of the
stem and branches was took, which showed the symptoms of
white mold disease and then planted 4 pieces of plants on
Potato Dextrose Agar (PDA) medium supplemented with
tetracycline at 200 mg/L and then incubated at 25±1 °C for 3
days. S. sclerotiorum colonies were purified.
Molecular diagnosis of Sclerotinia sclerotiorum using
Polymerase Chain Reaction (PCR) technology
(i) DNA extraction of fungus
The genetic material of the fungus (DNA) was isolated
after the growth of the S. sclerotiorum in petri dishes
containing the PDA. The ZR-Fungal/Bacterial DNA
MiniPrep
TM
kit was used by Zymo Research company.
(ii) Measuring the concentration and purity of DNA
Measure the DNA concentration and purity extracted in
the previous manner using a photovoltaic Nanodrop device
based on optical absorption.
647
(iii) Electrolysis of DNA on Agarose gel electrophoresis of
DNA
DNA was transferred to the Agarose gel to confirm its
quality after extraction or after polymerase chain reaction
(PCR) using different concentrations of gel according to the
target of the migration. Concentration of 1.5% of the gel to
detect PCR reaction results. The PCR reaction products were
carried out with the presence of a volume guide of DNA
known as the DNA ladder produced by Kapa USA, With the
following molecular weights: 100, 150, 200, 300, 400, 500,
600, 800, 1000, 1200, 1600, 2000, 4000, 5000, 6000, 8000,
1000 When the migration was complete, the beams were
observed and photographed using a UV transilumintor device
at a 360 nm wavelength. 1XTBE of dilution 10 mL of
10XTBE solution (base solution) in 90 ml sterile distilled
water to obtain 1XTBE concentration.
(iv) Polymerase chain reaction
Specialized initiator was used to detect the ITS region
of the ITS, the reverse strip called ITS4, which was obtained
from the Canadian Integrated Technologies Company,
Canada, as shown in table (1). The gene was multiplied by
the use of several polymerase reactions from the Korean
company INTRON, which consists of the reaction mixture
provided by the same company (Table 2) and the reaction
program as shown in Table (3).
Table 1 : Sequence of the specialized initiator for detection of the ITS gene in the Sclerotinia sclerotiorum.
Primer Sequence Tm (C) GC (%) Product size
Forward 5- TCCGTAGGTGAACCTGCGG -3 60.3 50 %
Reverse 5 TCCTCCGCTTATTGATATGC-3 57.8 41 %
500-650
base pair
Table 2 : Mixture of the specific interaction for diagnosis
gene.
Components Concentration
Taq PCR PreMix l
Forward primer
10 picomols/µl (1 µ l )
Reverse primer
10 picomols/µl (1 µ l )
DNA 1.5µl
Distill water 16.5 µl
Final volume 25µl
Table 3 : The optimum condition of detection
No.*
Phase Tm (ºC)
Time
No. of cycle
1- Initial Denaturation
95ºC 3 min.
1 cycle
2- Denaturation -2 95ºC 45sec
3- Annealing 52ºC 1 min
4- Extension-1 72ºC 1 min
35 cycle
5- Extension -2 72ºC 7 min.
1 cycle
*Each primer (Primers set supplied by IDT (Integrated DNA
Technologies company, Canada.). The PCR amplification was
performed in a total volume of 25µl containing 1.5µl DNA, 5 µl
Taq PCR PreMix (Intron, Korea) was dissolved separately with
sterile deionized distilled water as recommended by the company
for a concentration of 100 pmol/ ml (base solution). The primers
were then diluted to 10 µM / ml by adding 10 bicomol from the base
solution to 90 mL distilled deionized sterilized water and then
stored in the refrigerator until -20 °C. Transfer 5 microliters of PCR
product to 1.5% Agarose gel (90 min under 75 volt and 65 current)
using the DNA gel electrophoresis. After completion of the
migration, the gel was imaged at UV wavelength at 365 nm.
(v) Determination of sequences of nitrogenous bases
sequencing rules
Sequences of the nitrogenous bases of the polymerase
chain reaction (ITS) products were determined by sending
PCR reaction products with only the front-end stripe (ITS1)
to the Korean company Macrogen for the purpose of
knowing the DNA sequence of the fungus and determining
the fungus.
(vi) Analysis of nucleotide sequence data for fungus
genome
The sequences obtained from the Korean company
Macrogen were analyzed using the National Center for
Biotechnology Information (NCBI) in the search was
conducted using Basic Local Alignment Search Tool
(BLAST) program which is available at the National Center
Biotechnology Information (NCBI) online at
(http://www.ncbi.nlm.nih.gov) and BioEdit program and the
secondary Nucleotide blast was selected.
Test the pathogenicity
(i) Detection of pathogenic isolates using eggplant seeds
The pathogenecity of the Sclerotinia sclerotiorum
isolated from the affected stems of eggplant was tested
according to method of Bolkan and Butler (1974) using water
agar medium (20 agar, 1 liter distilled water). Place the
inoculated dishes in the incubator at a temperature of 25 ± 1
°C for 2 to 3 days. The seeds of the eggplant are sterile and
25 seeds / plate are placed in a circular manner near the edge
of the dish. 3 dishes were used for each isolation as
replicates, as well as the treatment of the control without
adding the fungus, incubated the dishes under 25 ± 1 °C and
the results were taken after 7 days. The percentage of
germination was calculated.
Effect of S. sclerotiorum pathogen isolates on eggplant
seedlings under the conditions of the wooden canopy
The pathogenicity of S. sclerotiorum isolates, which
included Ss-1, Ss-2, Ss-3, was tested on eggplant seedlings
under the conditions of the plastic house at the Technical
College/ Mussaib for 2017. In this experiment, a mixture of
soil was used after sterilization. The soil was distributed on
plastic pots with 1 kg of soil per pot. It was planted with
eggplant seedlings 6 weeks old and 3 replicates per isolate
with 2 plants per replicate. The agricultural operations of
fertilizer and irrigation for a 45 days was carried out. the S.
sclerotiorum grown on the PDA medium. They wounds were
worked a 1 cm long and 1 mm deep on the main stems and
branches of each plant and placed a pieces of the fungus
isolates on the wound taken from the 7-day fungal colony at
an 8 mm diameter, Polyethylene bags was used to covered
the plants to maintain moisture and prevent any external
contamination, while three replicates remained without
inoculated by pathogenic fungi as a control. The readings
were followed after the inoculation process. The disease
incidence was calculated in the light of the symptoms shown
Samah K.M. Al-Tameemi and Ahed Abd Ali Hadi Matloob
648
on the plant after approximately one month and according to
the following equation:
Disease incidence = No. infected plants\ sum of plants×100.
The severity of the infection was calculated according to the
following skill which included six degrees as follows:
0 No injuries,1 rot injury does not exceed 2 mm
longitudinal length of the wound., 2 Rot exceeds the length
of 2 mm to 4 mm longitudinally from the wound, 3 Rot
exceeds 4 mm to 6 mm longitudinally from the wound. 4 The
rot extends to more than 6-8 mm longitudinally on the wound
but is not completed round stem, 5 Rot more than 8 mm
longitudinally from the wound with full round the stem. The
upper part is sometimes wilt.
The percentage of severity was calculated according to the
Mckinney equation (1923) as follows:
Severity (%) = ((Plants in 1 degree ×1+… Plants in 5 degree
×5)/ all plants ×5) ×100%.
Evaluation of the efficacy of micro-organisms EM-1,
Pseudomonas fluorescens, and Nile flower extracts in the
protection of eggplant from S. sclerotiorum, causes white
mold under field conditions.
The field experiment was carried out in one of the fields
of Al-Mahawil district-Al-Azawia area (at the farm of Mr.
Hakim Shamran Atallah) on 27/10/2017. After the soil was
plowed, cleared and settled well, it was divided into 3 sectors
and to 3 m. Experiment treatments that included the
following: 1. Sclerotinia sclerotiorum (Sc-2). 2. Sc-2+
Pseudomanas fluorescens (Pf). 3- Sc-2+ EM-1. 4- Sc-2+
Water hyacinth extract (wh). 5- Sc-2+Pf+EM-1. 6- Sc-
2+Pf+wh. 7- Sc-2+EM-1+wh. 8- Sc-2+Pf+EM-1+wh. 9- Sc-
2+Topsin. 10- Control. 11- Pf alone. 12- EM-1 alone. 13- wh
alone. 14- Pf+EM-1. 15- Pf+wh. 16- EM-1+wh. 17- Pf+EM-
1+ wh. The soil was irrigated and planted with seedlings of
eggplant (Barcelona variety) at the age of 20 days at the rate
of 10 seedlings per replicate and the distance between plant
40 cm repeated 3 replicates per treatment. P. fluorescens 5-
day-old colony were added at 25 ml on plant before 5 days of
cultivating. EM-1 has been added to the soil at 25 mL for
treatments that need to be added during cultivation. The
chemical pesticide Topsin was added at a concentration of 1
ml/liter a day after the addition of the fungus. The S.
sclerotiorum, grown on the PDA medium was added where
worked a wound length of 1 cm and depth of 1 mm on the
main stem of each plant. The treatment of the water extract of
the Water hyacinth plant was added by spraying the seedlings
after a day of adding the fungus at a concentration of 15%.
The soil of the experiment was irrigated according to the
need of the plant. Crop Service Operations and fertilization
(20 g / m
2
) as the first batch after two weeks of seedling and
a second batch after 30 days of adding the first batch. The
results were calculated by calculating the disease incidence
and severity of infection after 190 days of planting with 3
randomly selected plants from each replicate and three
replicates / treatment. It also calculated the lengths of plants
and the wet and dry weight of plants and the yield weight of
the crop.
Results and Discussion
Isolate and diagnose the pathogen of white mold disease
on eggplant plant
The results of isolating and diagnosis showed three
isolates of the Sclerotinia sclerotiorum on the PDA medium.
These were taken from the samples of plants that showed the
symptoms of white mold disease. The isolation of Sc-1, Sc-2,
Sc-3 isolates of Abu Jassem, Al-Badaa and Mashroa Al-
Mussaib respectively. The whole of the dish was covered
with fungal white growth after 4-5 days of inoculation. Note
that the composition of the fungus was attached to the dish
cover from the inside. The formation of the sclerotia was
observed after 7 days of fertilization with the fungus
collecting in the form of white blocks (Figure1), and then to
the black color as the composition of the sclerotia at the edge
of the dish and marked the These results are consistent with
the results of several studies that showed the importance of
fungus as a cause of white mold (Paret and Olson, 2010).
Fig. 1 : The cultural and Microscopic characteristics of Sclerotinia sclerotiorum on the PDA medium.
Molecular identification
The results of the electrophoreses of the DNA on the
Agarose gel 0.8% concentration of the ZR-Fungal/ Bacterial
DNA MiniPrep
TM
kit showed good result in DNA extraction.
The results of the PCR transfer on the Agarose gel showed a
1.5% concentration with a package size of 650 bp (Fig. 2).
These results correspond to the study carried out by the
researchers (Grabicoski et al., 2015; Tok et al., 2016; Ali and
Aljarah, 2018). The users are the same as the primer of the
fungus and got molecular identified of Sclerotinia
Effect of some biological control agents in reducing the disease incidence and severity of white mold disease
on eggplant caused by Sclerotinia sc lerotiorum
649
sclerotiorum. After the results of the nucleotides sequences
of the fungus genome were obtained with the use of the
Korean frontal stripe (ITS1) from the Korean company
Macrogen, they were matched with the sequential S.
sclerotiorum isolate recorded in the National Center for
Biotechnology Information (NCBI) for determine the species
using the https://blast.ncbi.nlm.nih.gov/Blast.cgi window
located on the official website of the World Web (NCBI).
The results of the analysis of the nucleotide sequences of
PCR interaction showed the presence of the S. sclerotiorum.
The results showed that the Iraqi isolate were identical with
LC318720 by 100%. These results were similar to the results
of Ali and Aljarah (2018) which appeared the sequences
analysis revealed that the four isolates shared 99-100%
identities with the equivalent sequences of the fungal isolates
conserved international Gen Bank. The results of the
molecular diagnosis in this study are the first of its kind in
Iraq and which describe the diagnosis of this fungus based on
the molecular characteristics of the fungus.
Fig. 2 : Results of the electrical relay of the PCR products of the ITS initiator, which reveals the genetic area confined between the regions
ITS1 and ITS4 on the 1.5% Agarose gel (60 min, 70 V, 65 amp current) The beams were seen using a trans illuminator On the ultraviolet
light in work, such as M = DNA Marker.
Detection of pathogenic isolates of the Sclerotinia
sclerotiorum using eggplant seeds
The results showed that the tested isolates of S.
sclerotiorum showed a significant decrease in the percentage
of eggplant seeds germination. It was noted that there was a
difference in the pathological potential of fungus isolates
(Table 4). Sc-2 isolates isolated from the Badaa district by
their pathogenicity to isolate Sc-1 and Sc-3. The effect of
reducing the percentage of germination as the number of
seeds was 0.67, the percentage of germination was 2.66%.
Sc-1 and Sc-3 isolates achieved 53.33% and 65.33%
respectively. The reason for the variation of isolates in their
effect on the percentage of eggplant seed germination may be
due to the genetic difference between the isolates collected
from different regions. The decrease in the percentage of
eggplant germination in S. sclerotiorum treatment is due to
its ability to produce the host cell walls, Proteases Pectinases,
Hemicellulases, Endo Polygalacturonases, Oxalic Acid (OA)
and the toxicity of this acid to host tissues (Riou, 1991,
Poussereau et al., 2001; Girard et al., 2004).
Table 4 : Effect of Sclerotinia sclerotiorum isolates on the
eggplant seed germination rate.
Germination
(%)
Number of
germinated seeds Treatments
53.33 13.33 Sc-1
2.66 0.67 Sc-2
65.33 16.33 Sc-3
100 25.00 Control
6.522 1.630 L.S.D. (P<0.05)
Sc= Sclerotinia sclerotiorum The number near the symbol
represents the isolate number.
Effect of S. sclerotiorum isolates on eggplant seedlings
under the conditions of the wooden canopy
The results of Table 5 indicate that all tested isolates
were pathogenic to eggplant seedlings with a high infection
rate of 100% with a difference in the severity of infection for
each isolate, causing a significant increase in the severity of
S. sclerotiorum infection compared with the control
treatment, which had a zero disease incidence of infection.
The results showed that isolate Sc-2 achieved the highest
values of the percentage severity of eggplant seedlings
infection at 82.22%, followed by the isolation of Sc-1, with
42.22% of the severity of infection. These results are in line
with the results of detection of the pathogenicity of isolates S.
sclerotiorum on eggplant seeds under laboratory condition.
Table 5 : Effect of S. sclerotiorum pathogen isolates on
eggplant seedlings.
Severity
(%)
Disease
incidence
(%)
Treatments
42.22 100 Sc-1
82.22 100 Sc-2
31.11 100 Sc-3
0.00 0.00 Control
3.134 6.656 LSD (P<0.05)
The pathogenic fungus produces a group of plant-cell
wall degraded enzymes such as Proteases and Pectinases that
play an important role in pathogenicity of S. sclerotiorum.
The hydrolysis of the pectin acts to weaken the cell wall,
facilitating the penetration and colonization of the host and
Samah K.M. Al-Tameemi and Ahed Abd Ali Hadi Matloob
650
supplying the fungus with the sources of carbon necessary
for growth (Agrios, 2005). The result of this experiment was
the selection of isolate Sc-2, which achieved the highest
percentages of the intensity of the infection of eggplant
plants for subsequent experiments.
Evaluation of the efficiency of some biological control
agents in reducing the disease incidence and severity of
white mold disease on eggplant caused by Sclerotinia
sclerotiorum and some growth criteria under field
conditions.
The results of the field experiment (Table 6) showed
that all the treatments used in the experiment, which included
the P. fluoresescens, EM-1 and the water extract of the Water
hyacinth plant, reduced the negative effects of the S.
sclerotiorum and clearly protected the eggplant from
infection by white mold disease, which resulted in a
significant reduction in the percentage of infection and
severity and in varying rates compared with the treatment of
S. sclerotiorum disease alone, which had a treatment rate of
100% and severity of infection 56.67%, where the treatment
of integration between the biological product EM-1 and P.
fluorescens and Water hyacinth extract decreased the disease
incidence rate into 16.67% and the severity was 10.00%. The
treatment P. fluorescens significantly reduced the infection
rate by 50.00% and the severity was 33.33%. Regarding the
addition of single or integrated biological agents. The results
showed the efficiency of the water extract of the Water
hyacinth plant and the EM-1 significantly reduced the disease
incidence and severity of infection by 33.33% and 26.67%
respectively. approach of treatment of overlap between the
water extract of the Water hyacinth and P. fluorescens was
33.33% and 23.33%. The interaction between P. fluorescens
and EM-1 has demonstrated a high efficiency in reducing the
disease incidence and severity compared with the treatment
of single fungus. The results showed that the efficiency of the
chemical pesticide Topsin in reducing the incidence of
pathogenic fungi, thus reducing the disease incidence and
severity of infection.
Table 6 : Effect of some biological control agents on
Sclerotinia sclerotiorum causing of white mold disease on
eggplant c under field conditions.
Severity
(%)
Disease
incidence (%) Treatments*
56.67 100.00 Sc-2
33.33 50.00 Sc-2+ Pf
35.00 41.66 Sc-2+ EM-1
28.33 66.67 Sc-2+ wh
13.33 25.00 Sc-2+ Pf+ EM-1
23.33 33.33 Sc-2+ Pf+wh
26.67 33.33 Sc-2+ EM-1+wh
10.00 16.67 Sc-2+Pf+ EM-1+wh
8.33 33.33 Sc-2+Topsin
6.67 8.33 Control
0.00 0.00 Pf
0.00 0.00 EM-1
0.00 0.00 wh
0.00 0.00 Pf+ EM-1
0.00 0.00 Pf+wh
0.00 0.00 EM-1+wh
0.00 0.00 Pf+ EM-1+wh
3.44 * 5.36 LSD (P<0.05).
*Each number represents the rate of 3 replicates. Sc=Sclerotinia
sclerotiorum, Pf = Pseudomonas fluorescens, EM-1 = Effective
microorganisms, wh = water extract of Water hyacinth plant.
These results were consistent with several studies that
showed that the overlap between biological control agents
was more effective in reducing the severity of plant diseases
than if a single factor was used alone (Nandakumar et al.,
2001; Saravanakumar et al., 2007; Young Cheol et al., 2008;
Latha et al., 2009). The efficacy of P. fluorescens is due to
the control of the pathogen and the reduction of the rate and
severity of infection to the ability to produce various types of
antibiotics such as Oomycin, Pyrroles, Phloroglucinal and
Pyrolnitrin against pathogenic fungi (Voisard et al., 1994;
Sharma et al., 2002). This bacteria also stimulate systemic
resistance, The resulting plants produce an inhibitory
pathogenic compounds such as Phytoalexin (Van Peer et al.,
1991; Bakker et al., 2007). The effective effect of EM-1 is to
reduce the severity of the disease because it contains a
corresponding group of beneficial microorganisms that
inhibit the growth of pathogenic fungi (Surgeon, 2011). The
results showed that the efficiency of the use of biological
control agents alone or the interaction between the bacteria P.
fluorescens and EM-1 and the water extract of Water
hyacinth in the protection of eggplant did not show any
infection with pathogen S. sclerotiorum due to the superiority
of control agents in the elimination of injury, The percentage
of severity of infection in all these transactions was 0%. The
results (Table 7) showed the positive effect of the
coefficients on increasing the plant height, wet and dry
weight of the eggplant plants, as all the treatments achieved a
significant increase in the measured growth parameters. The
treatment of the interaction between the Water hyacinth
extract and the biological resistance factors, which included
P. fluorescens and EM-1, was the most effective in
increasing the plant length of 152.00 cm and wet dry weight
626.67 and 160.42 g respectively, compared to the treatment
of pathogenic fungus alone, The average length of the plant
was 94.00 cm and the wet and dry weight was 310.67 and
70.77 g respectively. The ratio of the Water hyacinth extract
and the P. fluorescens was increased in the length which was
143.33 cm while the wet and dry weight was 566.67 and
151.35 g respectively. The treatment of EM1 with the
presence of fungus caused a significant increase in plant
height of 127.00 cm where the wet weight was 455.00 g and
dry weight was 131.00 g. The interaction coefficients
between the Water hyacinth extract and the P. fluorescens
and the EM-1 with S. sclerotiorum showed a significant
increase in plant height Where it was 139.32 cm and the
weight was wet and dry 466.67 and 139.50 g on the relay.
These results show that the bioprotective agents, which
included P. fluorescens and EM1, were highly effective in
protecting eggplant plants from S. sclerotiorum infection and
increased growth parameters. The results agree with Chang et
al. (1986) that the efficiency of P. fluorescens increase in
plant growth is due to the ability to release growth substances
such as organic acids and growth regulators such as Indol
Acetic Acid (IAA), which helps to increase germination rate
and improve plant growth. Bacteria colonize treated plant
roots, thus forming a strong, Stress factors and induced
systemic resistance in plants (Bakker et al., 2003; Vanloon
and Bakker, 2003). P. fluorescens play an important role in
providing additional amounts of N element by means of
various mechanisms such as N air fixation or analysis of
mineral rocks and the release of elements that help the
Effect of some biological control agents in reducing the disease incidence and severity of white mold disease
on eggplant caused by Sclerotinia sc lerotiorum
651
growth of roots and deepening in the soil, and thus increase
its ability to absorb water and nutrients.
Table 7 : The efficiency of some biological control and
Topsin pesticide in plant length, wet and dry weight and
weight of eggplant yield under field conditions.
Weight (g) Plant
yield
(kg) Dry Wet
Plant
length
(cm)
Treatments
11.77 70.77 310.67
94.00 Sc-2
22.68 122.09
428.67
121.00
Sc-2+ Pf
23.99 131.00
455.00
127.00
Sc-2+ EM-1
21.31 116.91
416.67
115.33
Sc-2+ wh
23.15 124.17
431.67
122.67
Sc-2+ Pf+ EM-1
23.42 132.06
446.67
132.33
Sc-2+ Pf+wh
23.12 128.67
456.67
129.33
Sc-2+ EM-1+wh
24.05 139.50
466.67
139.32
Sc-2+Pf+ EM-1+wh
18.37 93.67 393.33
119.32
Sc-2+Topsin
20.42 89.17 383.33
113.67
Control
23.80 135.49
456.00
134.67
Pf
24.43 143.13
463.00
137.67
EM-1
23.55 131.21
453.33
124.33
wh
28.71 147.96
500 138.00
Pf+ EM-1
26.24 151.35
566.67
143.33
Pf+wh
25.36 138.35
613.33
140.67
EM-1+wh
25.36 160.42
626.67
152.00
Pf+ EM-1+wh
1.481* 4.418*
22.16 *
2.012 *
LSD (P<0.05).
*Each number represents the rate of 3 replicates. Sc=Sclerotinia
sclerotiorum, Pf = Pseudomonas fluorescens, EM-1 = Effective
microorganisms, wh = water extract of Water hyacinth plant.
Table 7 also showed a positive effect on the increase in
the total number of eggplant plants since all the treatments
achieved a significant increase in the weight of the yield
compared to the single fungus treatment. We note that all the
interaction factors between the biological factors and the
presence of pathogen achieved a significant increase in
weight and the treatment of the interaction between the water
extract of the Water hyacinth, EM-1 and the bacteria P.
fluoresescens, where the weight of 29.96 kg compared with
the treatment of fungus S. sclerotiorum, which gave a weight
of 11.77 kg and the results showed the efficiency of
interference coefficients between the factors of biological
control increase growth measures of eggplant plant, which
consisted of wet and dry weight and yield. All biological
control agents gave good results in increasing vegetative
growth parameters. The results are in line with Lavania et al.
(2006) and AL-Kaim (2015), that the EM-1 has increased the
growth parameters of the tested plants in general. The wet
and dry weight. The microorganisms contained in this Bio-
formula are due to several species of aerobic and anaerobic
bacteria such as photosynthesis Rodopseudomonas spp.
Which secrete various substances such as amino acids and
carbohydrates that promote plant growth and increase the
fertility of the soil and contains bacteria capable of
converting sugars to lactic acid, and the formation of lactic
acid to reduce the degree of pH, which helps to dissolve the
nutrients, as well as Lactic acid itself accelerates the
decomposition of complex organic matter and has a strong
inhibitory effect that resists the growth of certain pathogenic
fungi, including S. sclerotiorum.
Samiyappan et al. (2011) suggest that the use of PGPR,
which includes bacteria P. fluorescens leads to a significant
increase in the quality and quantity of production, as P.
fluorescens produce plant growth promoters such as
Gibberellins and Auxins that increase their growth and
productivity (Thomashow and Weller, 1996). P. fluorescens
also have the ability to produce compounds Such as
Siderophores, which have low molecular weight and have
high binding ability to iron ions, which compete with the iron
element and make it unsuitable for other microorganisms,
including plant pathogens, which have been shown to inhibit
many pathogens. (Mavrodi et al., 2001; Landa et al., 2002).
The use of biological control agents, as well as the use of
bacteria, Water hyacinth extracts by adding them to the soil
of the field (without pathogen) showed a significant increase
in aggregate weight. This is due to the fact that these
biological control agents have different mechanisms that
enable and work with them to stimulate the growth of the
plant and then increase the yield of plants.
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Chapter
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