Managing soil-borne plant pathogens by means of biological agents is become widely popular and practical nowadays to avoid getting problems from synthetic control measures, this ppt clear describes various important bioagents in the management of soil-borne plant pathogens

1. Presented by
M. Surya
2nd year M.Sc. Agri.
Dept. of Plant Pathology
Annamalai University
28-Nov-21
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2. INTRODUCTION
Soilborne pathogens are most destructive pathogen in crop
production.
Soilborne pathogens such as Rhizoctonia spp., Fusarium
spp., Verticillium sp., etc causes yield loss.
Often survive for long period in plant debris , soil organic
matter , resistent structures like microsclerotia , sclerotia,
chlamydospores and oospores.
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3. What is soilborne disease?
The diseases that are caused
by pathogens which persist
(survive) in the soil matrix and
in residues on the soil surface.
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4. Biology of Soil borne Pathogen
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Soil inhabitants: Pathogen can survive for longer periods (> 5
years).
Soil invaders : Pathogen can survive for shorter periods (< 5
years.

5.  Many factors in the soil that influence the activity of
soilborne pathogens and diseases : Soil type, Texture, pH,
moisture, temperature and nutrient levels are among them.
 Soils that drain poorly , tend to favour the survival and
distribution of soilborne pathogens.
 Similarly, soilborne pathogen can also be more severe in
wet soils than in dry soils .
 Only a few root diseases are favored by drier soils.
FACTORS THAT INFLUENCE
THE DISTRIBUTION
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6. Predominant Soil borne Pathogens
Fungal Soil-borne Pathogens
 Fusarium spp. (Fusarium culmorum, F. fujikuroi, Fusarium equiseti,
F. graminearum, F. heterosporum , F. langsethiae, F. proliferatum, F.
solani , F. sporotrichoides, F. virguliformae, F. oxysporum f. sp.
cucumerinum, Fusarium oxysporum f. sp. cubense)
 Phytophthora spp. (P
. cactorum, P
. cinnamomi, P
. capsici, P
.
drechscleri, P
. myriotylum, P
. nicotianae, P
. parasitica and
P
. ramorum)
 Pythium spp. (Phythium aphanidermatum, P
. delicensi, P
. spinosum
and P
. debaryanum)
 Sclerotium spp. (S. cepivorum, S. rolfsii and S. sclerotiorum)
 Macrophomina phaseolina 28-Nov-21
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7. FUSARIUM
B
A
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8. PHYTOPHTHORA
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9. PYTHIUM
A B
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10. SCLEROTIUM SPP
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11. MACROPHOMINA PHASEOLINA
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12. RHIZOCTONIA SOLANI
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13.  Aphanomyces cochlioides and A. eutichus
 Didymella bryoniae
 Corynespora cassiicola
 Gaeumannomyces graminis var. tritici
 Cylindrocladium crotalariae
 Heterobasidium annosum
 Monilochaetes infustans
 Phomopsis asparagi
 Phymatotricum omnivorum
 Pyrenochaeta lycopersici
 Ridigoporus microporus
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14. Bacterial Soil-borne Pathogen
 Agrobacterium tumefaciens
 Ralstonia solanacaerum
 Burkholderia cepacia
 Streptomyces scabies
 Rhizomonas suberifaciens
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15. CULTURAL
METHOD
BIOLOGICAL
METHOD
CHEMICAL
METHOD
COMBINED
METHOD
INTEGRATED
MANAGEMENT
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16. SOILLESS
CULTURE
SANITATION
LEGAL METHODS
SOIL SOLARIZATION
SOIL STEAM
STERILIZATION
CROP ROTATION
SEAWEED
FERTILIZERS
BIOFUMIGATION
SOILLESS CULTURE
ANAEROBIC SOIL DISINFESTATION
SANITATION
LEGAL METHODS
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17. PROVIDING GOOD SOIL
DRAINAGE AND GOOD AIR
CIRCULATION AMONG PLANTS
 Removal of dead or infected plants .
 Good soil drainage reduces the number and activity
of certain Oomycetes pathogens.
 Flooding fields for long periods or dry fallowing may
also reduce the disease.
 Irrigation also helps to reduce the soil borne disease.
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18. Sanitation
 To remove the plant debris.
 Wash soil off the farm equipment.
 Avoid working in fields when plants are wet .
 Ploughing under infected crop debris.
Gurel et
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19. Legal Methods
 The long distance transfer of soil borne plant pathogens
may occur through packing materials, containers, plant
material, seeds, plant products, soil, animals or even
humans.
Pathogen
Phytophthora ramorum, P
. drechsleri, P
. hedraianta,
P
. hibernalis, P
. nicotianae, P
. palmivora and P . syringae
Goss et
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20. SOIL SOLARIZATION
 The primary commercial use of solarization involved sunny
and warm lands.
 It is based on the increased soil temperature at soil depth of 5
cm, transparent polyethylene sheet causes plant pathogens .
 The reduction in soil borne pathogens, soil solarization also
leads to increased growth response of plants.
 Soil solarization also integrates with other techniques such as
mulching , soil amendments to enhance its overall
effectiveness against pathogen and increase crop yield.
Harsimran et al. (2017)
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21. 28-Nov-21
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22. Soil Steam Sterilization
 To sterilize the soil by
using hot steam in the
open field , high
tunnels or greenhouses.
 It involves the injection
of hot water vapors in
the soil using boilers
and conductors.
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23. Anaerobic soil disinfestations
 Decomposable amendments rice bran, fresh crop residues,
soybean flour and vineasses, covering it with plastic film and
irrigating to saturation .
 Anaerobic soil disinfestations results in decreased in soil redox
potential and composition of soil microbiome.
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24. 28-Nov-21
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25. Crop Rotation
Crop rotation is associated
with enhanced soil fertility ,
improvement in soil
chemical, and physical
properties, good soil water
management and soil
erosion control.
PATHOGEN HOST REFERENCE
F. virguiliforme Soyabean Harbach et al.(2017)
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26. Black rot ( Ceratocystis fimbriata)
Stem rot (F. oxysporum)
Scurf (Monilochaetes infuscans) disease of sweet
potato can be controlled by crop rotation.
Crop sequences with oat - potato, Annual Rye grass-
potato , clover-potato.
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27. Seaweed Fertilizers
 The high fiber content of seaweed act as a
soil conditioner and moisture retention , the
mineral content is useful of fertilizer and
trace elements.
Sea Weed Mode of action REFERENCE
Soleria robusta Suppress the root rotting growth
of fungus
Sultana et al.
(2011)
Ecklonia
maxima
Reduced the root knot infestation
and increased the growth of
tomato plants
Ara et al .(2005)
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28. Sea weeds were also effective on egg
plant, which is highly susceptible to root
knot nematode under field condition.
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29. Biofumigants
 Biochemical compounds are
directly control the harmful
soilborne plant pathogens .
 Biofumigant is incorporating
the soil amendment into the
soil , which in turn produces
organic compounds during the
development of succeeding
crop species. Helps to defend
against pests and pathogens.
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30. Pathogen Cover Crop
Suppressio
n (%)
Reference
Aphanomyces
eutieches
Sinapis alba 32
Muehlchen et al .
(1990)
Pyrenochaeta
lycopersici
Brassica rapa
12-52
Amenduni et al.(2004)
Brassica oleracea 23-43
Stephens et al. (1999)
Pythium sp.
Brassica napus 0
Brassica juncea 0
Ralstonia
solanacearum
Brassica juncea 62
Akiew and Trevorrow.
(1999)
Rhizoctonia solani Brassica juncea 25 Van Os et al . (2004)
Sclerotinia minor
Brassica juncea 68
Daugovish et al
Sinapis alba 91
Streptomyces scabies Brassica oleracea 90
Gouws and Wehner.
(2004)
Verticillium dahliae Brassica oleracea 35 Subbarao (1996)
Cover crops with effective against soil borne pathogen
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31. 28-Nov-21
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32. Soilless Culture
 Soilless culture is an
effective alternative
to soil systems and
replace methyl
bromide.
 Degradation of soil
due to erosion and
accumulation of salts
can cause the plant
growth.
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33. SOILLESS CULTURE
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34. 28-Nov-21
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35. Soil Fertility and Plant
Nutrients
 Adequate nutrition can make the plant
more tolerant or resistant to disease .
 Mineral nutrients regulate the metabolic
activity is related with plant resistance
pathogen virulence.
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36. Nutrient Disease Causal
Organism
Crop Presence Of
Nutrient
Reference
A. PRIMARY NUTRIENT
Nitrogen Gummy
stem
blight
Didymella
bryoniae
Watermelo
n
Severity
increased dose
N
Santos et al.
(2009)
Potassium Sheath
blight
Rhizoctonia
solani
Rice Resistance
increased with K
Schurt et al.
(2015)
Phosphorus Root rot Rhizoctonia
solani
Faba bean Severity of
infection
decrease with P
supply
Mousa (2016)
B. SECONDARY NUTRIENT
Calcium Stem rot Phytophthora
sojae
Soyabean Resistance
increased with
Sugimoto
(2011)
Sulphur Potato Streptomyces
scabies
Potato Possibility in
reduction in
severity by S
application
Huber (1980)
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37. C. MICRONUTRIENT
Zinc Banana wilt F. oxysporum
f.sp.cubense
Banana Resistance
increase with Zn
Sanjeev and
Eswaran (2008)
Pythium rot Pythium
deliense
Cucumb
r
Resistance
increase with Zn
Kucukyumuk et
al.(2014)
Chlorine Root rot Cochliobolus
sativus
Barley Reduction with Cl
fertilizer
Timm et al.
(1986)
Manganes
e
Take all Gaeumannomyc
es graminis var
.tritici
Wheat Resistance
increases with
Carrow et al.
(2001)
Copper Sheath
blight
Rhizoctonia
solani
Rice Resistance
increased with
Khaing et al.
(2014)
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38. Chemical method
Impact of long term fungicide and fumigants on
microbial growth , reduced fertility and the emergence
of fungicide resistance in pathogens.
Chemical Pathogen Reference
Azoxystrobin Rhizoctonia solani Alice (2007)
Cyprodinil and
Fludioxonil
Sclerotinia sclerotiorum and
S. minor
Matheron (2004)
Acibenzolar-S-methyl
and Strobilurins
Corky root of tomato and
Vertillicium wilt
Bubici et al.(2006)
Dicarboximide and
Triazole
Certain fungal soilborne
disease
Budge (2001)
Fosetyl-Al Pythium and phytophthora
Rekanovic et al.
(2017)
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39. Methods of soil treatment
Soil drenching
Broadcasting
Furrow application
Spot application
Strip application
Pits application
Plantation site application
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40. Biological method
 Biological control agents are organisms that
control pathogen and diseases through
antagonistic method.
Characteristics
 Highly effective bio-control agents must be able
to compete and live longer in soil and host
tissue.
 Inexpensive production and formulation agent
must be developed.
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41. Mechanism of Bio-control Agents
MECHANISM
OF
BIOCONTROL
AGENTS
Parasitism
Antibiosis
Competition
of host and
plant
nutrients
Induction
of resistant
in plants
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42. Application methods of
biocontrol agents
 Seed treatment
 Seedling dip
 Seed bio-priming
 Foliar application
 Soil application
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43. Bio-control
Agents
Target Pathogen
Mode of
Action
Reference
Bacillus sp. (B.
subtilis, B.
amyloliquefaciens,
B. firmus and B.
pumilus)
Pythium sp., Fusarium
sp., Rhizoctonia solani,
and Aspergillus flavus
Competition,
Direct antibiosis,
Induced
resistance
Shafi et al.(2017)
Purpureocillium
lilacinum QLP 12
Vertillicium dahlia,
R. Solani
Parasitism Lan et al.(2017)
Pseudomonas spp..
Pythium spp and
R. solani
Production of
antibiotics,
Siderophores and
Volatiles
Howell (1980)
Streptomyces spp.
Phytomatotrichum,
Aphanomyces,
Monosprascus,
Armillaria and
Geotrichum.
Mycoparasitism Franca et al.(2015)
Trichoderma sp.
(T. atroviride,
T. asperellum)
Rhizoctonia, Fusarium,
Alternaria.
Competition
resistance and
hyperparasitism
Pertot (2015)
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44. Bio-control
Agents
Target Pathogen
Mode of
Action
Reference
Bacillus
amyloliquefaciens
Alternaria panax, C.
orbiculare, Botrytis cinera,
Penicillium digitatum, P
.
grisea
Inhibit the
mycelial growth
Ji (2013)
Streptomyces sp. P
. capsica, Corynespora
cassicola , F. oxysporum
Prenylated indole
derivative from
endophytic
bacteria
Zhang (2014)
Coniothyrium
minitans
Sclerotinia sclerotiorum
and S. trifoliorum
Lysis by chitinase
and beta -1,3
glucanase
Smolinska et al.
(2018)
Gliocladium
catenulatum
Didymella and
Cladosporium
Toxin production Ji et al.(2015)
Phlebiopsis gigantea Heterobasidium annosum Competition for
resources
Pertot et al.
(2015)
Pythium
oligoandrum
Gaeumannomyces ,
Ophistoma , Phoma,
Pseudocercosporella
Hyperparasitism Esteve et al.
(2015)
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45. Combined Methods Of Control
 Combining method of control is at the heart of integrated pest
management , may result either additive or synergistic effect.
 The goal of IDM methods is to measures that are more efficient ,
healthier and to reduce the amount of inoculum.
The solar heating of soil , amended with cabbage residues
eliminated F. oxysporum f.sp. conglutinans.
Ramirez (1988)
Combination of Bacillus megaterium and Carbendazim has an
effective control Fusarium crown and Root rot of tomato .
Omar et al.(2006)
Soil amendment with sea weeds with bio-control agents reduced the
root knot nematode .
Sultana et al.(2011)
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46. Conclusion
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