The document summarizes sustainable approaches for managing soil-borne plant pathogens. It discusses various methods including cultural, physical, biological and chemical controls. Cultural controls involve practices like crop rotation, mixed cropping, nutrient management, and cover crops which help reduce pathogen populations in the soil over time. Physical controls use factors like solarization and flooding to raise soil temperatures and kill pathogens. Biological controls utilize beneficial organisms like Trichoderma that compete with or inhibit pathogens through various mechanisms. An integrated approach applying several control methods together can provide effective sustainable management of soil-borne diseases.

2. CREDIT SEMINAR
ON
A SUSTAINABLE APPROACH FOR
MANAGEMENT OF SOIL BORNE PATHOGENS
PRESENTED BY;
PRAKASH MANI KUMAR
M.Sc. (Ag), 3rd sem
M/PP/94/2016-17
Deptt. of Plant Pathology

3. CONTENTS
INTRODUCTION
WHY PLANT DISEASE OCCURS?
PRINCIPLES OF PLANT DISEASE MANAGEMENT
CULTURAL METHOD OF DISEASE CONTROL
PHYSICAL METHOD OF DISEASE CONTROL
BIOLOGICAL METHOD OF DISEASE CONTROL
CHEMICAL METHOD OF DISEASE CONTROL
CONCLUSION
HOST RESISTANCE IN DISEASE MANAGEMENT

4. INTRODUCTION

5. Environmental
sustainability
Social
sustainability
Financial
sustainability
The application of sustainable practice in the category of Agriculture,
business, society, environment and in personal life by manage them in
the way that will be benefit current and future generation

6. PREDOMINANT SOILBORNE PATHOGENS
 FUNGI- Sclerotium rolfsii, Rhizoctonia solani, Fusarium sp, Pythium, Phytophthora etc.
 BACTERIA- Erwinia, Raltsonia, Rhizomonas, Agrobacterium, Streptomyces etc.
 VIRUS- Wheat mosaic virus
 NEMATODES- Meloidogyne, Heterodera, Longidorus, Paratrichodorus, Trichodorus etc.
(Veena et al., 2014)

7. WHY PLANT DISEASE OCCUR..?

8. ENVIRONMENT
TIME
favourable
ENVIRONMENT
HOST
Susceptible
PATHOGEN
Virulent

9. PRINCIPLES OF PLANT DISEASE
MANAGEMENT

10. PATHOGEN EXCLUSION
AVOIDANCE OF PATHOGEN
PATHOGEN ERADICATION OR REDUCTION OF
INNOCULUM
PLANT PROTECTION
RESISTANT VARIETY
THERAPY

11. 45 %
28%
8%
4%
15%
Chemical method
Cultural method
Physical method
Biological method
Host resistance
Practices for sustainable management
of soil borne plant disease

12. 1.CULTURAL PRACTICES

13. Cultural practices involves all the activities carried out on
the farm before, during and after planting of crops. They are
grouped into: pre-planting, planting and post-planting operation.
Cultural practices involves the principle of:
 Avoidance
 eradication
 exclusion

14. Crop rotation
Date of
sowing
Nutrient
management
Organic
amendment
Cover cops
Depth of
sowing
Mix
cropping
CULTURAL METHODS INCLUDES

15. CROP ROTATION

16.  Crop rotation is the practice of growing a series of dissimilar or
different types of crops in the same area in sequenced seasons.
 When the same crop is grown in the same field year after year then
many diseases build up in the soil.
 Rotation to a non-susceptible crop can break this cycle by reducing
pathogen levels.
 It help in the control of those pathogens which are survive long time
in the soil without a host.
Eg- Fusarium Sp

17. VEGETABLES DISEASE YEAR OF ROTATION
Asperagus Fusarium rot (F. proliferatum) 8
Beans Root rot (F. phaseoli) 3-4
Cabbage Club root (Plasmodiophora brassicae) 7
Cabbage Black leg (Phoma lingum) 3-4
Cabbage Black rot (X. compestris) 2-3
Muskmelon Fusarium wilt (F. melonis) 5
Parsnip Root canker (Itersonilia pastinacae) 2
Peas Root rot (Aphanomyces euteiches f. sp.
Pisi)
3-4
Peas Fusarium wilt (F. oxysporium) 5
Pumpkin Black rot (Didymella bryoniae) 2
Radish Club root (Plasmodiophora brassicae) 7
ROTATION PERIODS TO REDUCE VEGETABLE SOIL-BORNE DISEASES

18. MIXED CROPPING

19. PATHOGEN MAIN CROP SECOND CROP EFFECCT REFERENCE
Fusarium oxysporum
f. sp. ciceris
Chick pea Linseed Reduce disease
incidence
Agrawal et al.,
2002
Otten et al., 2005
Rhizoctonia solani Radish Mustard Reduce disease
progress
Gaeumannomyces
graminis var. tritici
Wheat Grasses Reduce disease
severity and
incidence in bioassay
Gutteridge et al.,
2006
Fusarium oxysporum
f. sp. niveum
Watermelon Rice Reduced wilt Renet et al., 2007

20. DATE OF SOWING

21.  Early and delayed sowing of crops enables it escape critical period
of disease incidence.
 Peas and chickpea sown in October usually suffer heavily from root
rot and wilt (a complex of Fusarium, Rhizoctonia and Sclerotium).
When these crops are sown late, the diseases are not so severe or
almost absent.
 Avoiding cool and cloudy days for planting will help to reduce red
rot of sugarcane. Late sowing of winter wheat and barley is
considered to be the most effective measures in reducing take all
disease of wheat.

22. Effect of planting dates on days to first symptoms appearances, vine mass and tuber yield of
potato at Chitwan, Nepal.
DATE OF PLANTING DAYS TO 1ST
SYMPTOMS
APPEARANCE
(DAP)
VINE MASS(t ha-1) TUBER YIELD(t ha-1)
25th October 40.33 6.77 16.65
4th November 30.00 4.28 9.171
14th November 26.33 3.01 6.695
24th November 24.92 2.66 5.457
(Gaire et al., 2014)

23. NUTRIENT MANAGEMENT

24.  It play an important role in supreesion of disease.
 It influence the health of plants and their susceptibility to disease.
 Plants suffering a nutrient stress will be more susceptible to disease.
 It makes plant more tolerant or resistant to disease.
 The nutrient status of the soil and the use of particular fertilizers and
ammendments can have significant impacts on the pathogen’s
environment.

25. HOW CAN MINERAL NUTRITION PREVENT PLANT DISEASE.?
Mineral nutrition can affect two primary resistance mechanism:
a) Formation of mechanical barrier
Eg- thickness of cell wall
b) Synthesis of natural defence compounds
Eg- phytoalexins, antioxidants and flavanoids

26. Effect of form of ‘N’ on Plant Diseases
CROP DISEASE NO3-N NH4-N
Corn
Stalk rot (Fusarium) Increase Decrease
Root rot (Pythium) Increase Decrease
Soybean
Root rot (Aphanomyces) Decrease Increase
Cyst nematode (Heterodera) Increase Decrease
Wheat
Root rot (Fusarium) Decrease Increase
Take all (Ophiobolus) Increase Decrease
Cotton Root rot (Phymatotrichum) Increase Decrease
Wilt (Fusarium) Decrease Increase
(Huber et al., 2007)

27. PATHOGEN HOST/DISEASE FACTOR EFFECT
Phytophthora infestans Potato late blight
K Decrease
High K
High N
Increase
P. capsici Pepper blight K Decrease
P. drechsleri Pigeon pea blight High K
Low N
Decrease
P. parasitica Citrus gummosis High K
Low Ca
Increase
(Paul, 1983)
EFFECT OF ‘K’, ‘N’ AND ‘Ca’ ON SEVERITY OF PHYTOPHTHORA DISEASE

28. HOST PLANT DISEASES EFFECT OF ‘S’
Cotton, tomato Fusarium wilt, Verticillium wilt Decrease
Crucifers Club root Decrease
Potato Common scab, late blight, Stem
canker
Decrease
Soybean Rhizoctonia root rot Decrease
(Huber et al., 2015)
EFFECT OF ‘S’ ON DIFFERENT DISEASES

29. (Kausadikar et al., 2006)
ROLE OF MICRONUTRIENT DEFICIENCY ON SOIL-BORNE DISEASES
MICRONUTRIENT
DIFFICIENCY
DISEASE PATHOGEN
Boron(Bo)
Tomato Wilt Verticillium alboatrum
Beans Root rot Fusarium solani
Zinc(Zn)
Take all of wheat G. Graminis var. tritici
Rhizoctonia Root rot Rhizoctonia solani
Manganese(Mn) Take all of wheat G. Graminis var. tritici

30. SOIL AMENDMENT
(COMPOST)

31.  Compost increase the chemical and physical quality of the soil.
 It also increase the diversity of bacteria and fungi in the soil.
 Compost encourages healthy plants that are better equipped to
fight off disease and increase in yield.
 Root rot caused by Pythium and Phytophthora are generally
supressed by the high numbers and diversity of beneficial
microbes found in the compost.

32. SOME CASE STUDY OF SUPRESSION OF SOIL BORNE PATHOGEN BY
USING DIFFERENT TYPES OF COMPOST
COMPOST
MATERIAL
DISEASE SUPRESSION OBSERVED EFFECT REFERENCES
Hardwood
bark
Pythium ultimum in
cucumber plant
Hardwood bark centre pile(high
temperature, >60°C) was conducive and
after 3-4 days at 25°C became
suppressive. Suppression was due to
mesophilic organism, great microbial
activity and low levels of nutrients,
importance of microbiostasis.
Chen et al., 1988
Compost
municipal
waste
Phytophthora
nicotianae in citrus
seedling
Disease decreased increasing
proportions of one CMW(20% v/v)
Widmer et al.,
1998
Grape marc
compost
(GMC), Cork
compost(CC)
Fusarium oxysporum
f.sp. Lycopersici
(Fusarium wilt of
tomato)
GMC was the most suppressive, CC
was intermediate and peat and
vermiculite were conducive media.
Heated GMC was still moderately
suppressive. Importance of pH,β-
glucosidase activity and microbial
populations.
Borrero et al.,
2004

33. COMPOST
MATERIAL
DISEASE SUPRESSION OBSERVED EFFECT REFERENCES
Mature bio
solid compost
(sewage
sludge and
yard waste)
Sclerotina rolfsii in
bean plant
Prolonged compost curing negates
suppressiveness. Combination of
microbial populations and the chemical
environment were responsible for
pathogen suppression.
Danon et al., 2007
Cork compost
and light peat
Verticillium wilt of
tomato
Cork compost was suppressive in
comparision with peat. This compost had
higher microbial activity and biomass.
Borrero et al., 2002
Grape marc +
extracted
olive press
cake
(GM+EPC),
Olive tree
leaves+olive
mill waste
water
(OL+OMW)
and spent
mushroom
compost(SMC)
Fusarium oxysporium
f.sp. radices
lycopersici in tomato
plants
The three composts were highly
suppressive and suppression is related to
the presence of specific microorganism
Ntougias et al.,
2008; Kavroulakis
et al., 2010

34. COVER CROPS

35.  They are non-host crops sown with the purpose of
making soil borne pathogens waste their infection
potential before the susceptible main crop is grown.
 It will increase soil microbial diversity by enhancing
the soil microflora
 Create unfavourable environment
 Mustard and Brassica (Broccoli) helps to reduce the load of soil
borne pathogens.
(Divyarani et al., 2013)

36. DEPTH OF SOWING

37.  The depth of sowing has important effect on pathogen that
attack seedling.
 By delaying the emergence of seedling, deep sowing may
help to increase the resistance of a susceptible crop to
pathogen
 Deep sowing is advisable in case of disease caused by
Fusarium and Rhizoctonia sp.

38. 2. PHYSICAL METHODS

39.  It inactivate and immobilized the pathogen
 It creat a barrier in between pathogen and host plant and also their
vector.
 Plastic or net covering of row crops may protect the crop from
infection by preventing pathogens or vectors from reaching the
plants.
 Most commonly used physical agents for controlling plant diseases
are;
 Temperature (high and low)
 Dry air
 Light wavelength

40. SOIL SOLARIZATION

41.  Soil solarisation is a method of heating soil by
covering it with transparent polythene sheet during
hot period to control soil borne diseases.
 It trap solar energy and this energy cause physical,
chemical and biological changes in soil.
 Eg- control of Verticillium and Fusarium diseases in
vegetable crops in Israel, control of Verticillium
dahlias in orchard in California, USA and control of
chickpea and pigeonpea wilt in India.

42. SOME DISEASES ARE CONTROL BY SOIL SOLARIZATION
CROP DISEASE PATHOGEN
Tomato Didymello stem rot Didymella lycopersici
Cucumber Fusarium wilt Fusarium oxysporium
Cotton Fusarium wilt Fusarium oxysporium
Onion Pink root Plosmodiophoro brassicae
Peanut Pod rot Pythium myrothecium
Tomato Canker Clavibacter michiganensis
Potato Scab Streptomyces scabies
(Vegetable research and information centre, University of California)

43. HEAT STERILIZATION

44.  is a farming technique that sterilizes soil with steam in open fields or
greenhouses.
 Soil sterilization provides secure and quick relief of soils from
substances and organisms harmful to plants such as:
 It can generally achieved by heat produced electrically than supplied
by steam or hot water.
 bacteria
 viruses
 fungi
 Nematodes
Eg- 50°C- Nematode and some Oomycetes are killed
60°-70°C- most pathogenic bacteria and fungi

45. FLOODING

46.  Prolonged water logging leads to lack of oxygen
and accumulate CO2.
 Flooding the field to eliminate soil borne
plant pathogen in both physical and cultural
method.

47. PLANT DISEASE CONTROLLED BY FLOODING
PATHOGEN DISEASE
Alternaria porri f.sp. solani Alternaria blight of tomato and potato
Alternaria dauci Blight of carrot
Aphelenchoides besseyi White tip of rice
F. Oxysporium f. sp. cubens Wilt of banana
Verticillium dahlia Wilt of cotton
Phytophthora parasitica var. nicotianae Black shank of tobacco
Meloidogyne sp. Root knot of celery
Sclerotiana sclerotiorum White mold of vegetables
Pyrenophora teres Canker and blight of barley
(Stover, 1955: Rotein and Palti, 1969: Tarr, 1972: Palti, 1981)

48. 3. BIOLOGICAL CONTROL

49. TWO WAYS OF DISEASE SUPRESSION
By
Antagonistic
association
By
Symbiotic
association

50. Bio control agents suppress disease causing organism in
following ways;
 Competition: Beneficial organism out-compete disease causing plant
pathogens in the search for nutrients or colonization space in specific
habitats such as the root zones. Increased competition prevents
pathogens from becoming established and multiplying to levels that
cause plant disease.
 Antibiotics and secretions: produced by some microorganisms inhibit the
growth of plant pathogen.
Eg- Antibiotic production is common in soil-dwelling bacteria and fungi. For
example, zwittermicin a production by B. cereus against Phytophthora Root
rot in alfalfa
 Predation and parasitism: of plant pathogen by bio control agents (where
beneficial microbes use pathogen as a food)
Antagonistic
association

51. Hyphae of the beneficial fungus
Trichoderma wrap around the
pathogenic fungus Rhizoctonia.

52. USE OF TRICHODERMA IN DISEASE CONTROL
CROP DISEASE PATHOGEN
Elephant foot yam Collar rot Sclerotium rolfsii
Chilli, Tomato, Brinjal Damping off Pythium, Phytopthora,
Fusarium
Ginger, Turmeric, Onion Rhizome rot Pythium, Phytopthora,
Fusarium
Banana, Cotton, Tomato,
Brinjal
Wilt Fusarium oxysporium
(Ranasingh et al., 2006)

53. Symbiotic association
 In this association beneficial microorganism
protect the host plant from pathogen by
keeping an association with the host plant of
pathogen.
Example:- Mycorrhiza

54. MYCORRHIZAL FUNGI AND
DISEASE SUPPRESSION
MYCORRHIZA : it is an association between fungi and root
of higher plants
It is considered as the most
beneficial root-inhabiting organisms,
which forms a fungal mat over the
root and protect the root of plant
from the attack of soil borne
pathogen.

56. Protection from the pathogen Fusarium oxysporum was shown in a field
study using a cool-season annual grass and mycorrhizal fungi. In this
study the disease was suppressed in mycorrhizae-colonized grass
inoculated with the pathogen.
(Newsham et al., 1995)
in field studies with eggplant, fruit numbers went from an average of
3.5 per plant to an average of 5.8 per plant when inoculated with
Gigaspora margarita mycorrhizal fungi. Average fruit weight per plant
went from 258 grams to 437 grams.
(Matsubara et al., 1995)
EXAMPLE

57. SOIL SUPPRESSIVE

58. EXAMPLES OF DIFFERENT PLANT PATHOGENS CONCEALED BY DISEASE SUPPRESSIVE SOILS
PATHOGEN INVOLVED REFERENCE
Cyst nematode Heterodera sp. Kerry 1988; Westphal & Becker, 1999
Streptomyces scabies Menzies, 1959
Fusarium oxysporum Stotzky & Martin, 1963; Scher & Baker, 1980
Gaeumannomyces graminis var. tritici Cook & Rovira, 1976
Phytophthora cinnamomi Broadbent & Baker, 1974
Plasmodiophora brassicae Murakami et al., 2000
Pythium sp. Hancock, 1977
Rhizoctonia solani Henis et al., 1978, 1979

59. 4. CHEMICAL CONTROL

60.  A few chemical treatments, however, are aimed at eradicating or greatly
reducing the inoculum before it comes in contact with the plant. They include
soil treatments (such as fumigation), disinfestation of warehouses, sanitation of
handling equipment, and control of insect vectors of pathogens
 Chemicals in plant disease are used to create the toxic barrier between the
host surface and pathogen.
 These are applied in the soil as pre and post plant applications. Generally these
treatments are being given
in high value cash crops.
 Applied as soil fumigation, soil drenching and seed treatment.
 Fungicides like prothiocarb, propamocarb and metalaxyl are useful to control
the Oomycetes pathogens.
 Fosetyl – Al is the fungicide which controls the soilborne pathogens when it is
used as foliar spray.
 Chemical pesticides are generally used to protect plant surfaces from infection
or to eradicate a pathogen that has already infected a plant.

61. 5. HOST PLANT RESISTANCE

62. Growing of resistance plants is one of the
most effective and economical method.
Host plant resistance not only reduces
the crop losses but lessens the
expenditure incurred on disease control
as well as reduces the pollution hazards.
Resistance is of two types:
i) Monogenic (Vertical)
ii) Polygenic (Horizontal)

63. RESISTANT VARIETIES OF SOME CROPS
CROP VARIETIES DISEASE
Tomato Big beef, Celebrity tomato,
Sweet Chelsea
Wilt, Nematode, Tobacco
mosaic
Potato
Elba Late blight(highly resistant)
Kennbee, Sebago, Rosa Late blight (Moderate
resistant)
Meris bard Scab
Brinjal Arka anand Wilt

64.  Management of soil-borne diseases is most successful and
economical when all the required information pertaining to the crop,
disease affecting it, history of these in the previous years, resistant
levels of the host and environmental conditions to prevail is
available.
 Combination of disease management practices may have additive or
synergistic effects and such an approach is especially desirable in
the case of soilborne diseases which are entirely different
epidemiologically.
 All the management practices will be adopt in a proper way to
minimize the soil borne pathogens.