-By- AMOL VIJAY SHITOLE

1. WELCOME
“SUSTAINABLE MANAGEMENT OF SOIL-
BORNE PLANT DISEASES “

3.  Sustainable management to be defined as 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
 It create the ability to keep a system running indefinitely
without depleting resources the decision of making
sustainable management help to sustain our immediate
surrounding and environment.
 One important result is that farmers are able to minimize their
use of pesticides and fertilizers, thereby saving money and
protecting future productivity, as well as the environment
INTRODUCTION

4.  Intensive production in agriculture ,horticulture or forestry
increases the opportunity for disease to develop comparing to
other ecosystem,
 As plants and soils become sickers, growers have responded with
newer and more powerful chemicals in an effort to kill off the
pathogens, chemical intervention only serves to make things
worse over time.
 In this condition sustainable management of soil borne plant
disease is very important to minimize the activity that cause
damage to our environment .

5. PREDOMINANT SOILBORNE PATHOGENS:
Fungi: Sclerotium rolfsii,Rhizoctonia solani,Fusarium sp,
Pythium, Phytophthora etc.
Bacteria: Erwinia, Raltsonia, Rhizomonas, Agrobacterium,
Streptomyces etc.
Virus: Wheat soil borne Mosaic virus
Nematodes: Meloidogyne, Heterodera, Longidorus,
Paratrichodorus , Trichodorus etc.
Parasitic plants: Orobanche, striga

6. WHYTHEPLANTDISEASE?

7. PRINCIPLES OF PLANT DISEASE
MANAGEMENT
• Avoidance of pathogen
• Pathogen exclusion
• Pathogen eradication and reduction of inoculum
• Plant protection
• Resistant Varieties
• Therapy

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

9. 1) CULTURAL METHOD
It is an integral part of subsistence agriculture in
developing countries.
Cultural practices are now being consider as essential
back up procedure for management of resistant
varieties and also for chemical protected crops.
Cultural practices involves the principles of :
 Avoidance
 Eradication
 Exclusion

10. Cultural methods includes
Crop
rotation
Date of
sowing
Nutrient
management
Organic
amendment
Cover cops
Depth of
sowing
Management
of top soil

11. • Many diseases build up in the soil when the same
crop is grown in the same field year after year.
Rotation to a non-susceptible crop can help break
this cycle by reducing pathogen levels.
• The susceptible crop, related plants, and alternate
host plants for the disease must be kept out of the
field during the rotation period.
• it help control pathogens that can survive long
periods in the soil without a host.
• Example : Fusarium sp
CROP ROTATION AND DISEASE
SUPPRESSION

12. VEGETABLES DISEASE YEAR OF ROTATION
Asperagus Fusarium rot 8
Beans Root rot 3-4
Cabbage Club root 7
Cabbage Black leg 3-4
Cabbage Black rot 2-3
Muskmelon Fusarium wilt 5
Parsnip Root canker 2
Peas Root rot 3-4
Peas Fusarium wilt 5
Pumpkin Black rot 2
Radish Club root 7
Rotation periods to reduce vegetable soil-borne diseases

13. BENIFICAL CROPS PATHOGEN REDUCED PRECEDING CROP
(host)
Rice Verticillium dahliae Cotton
Peas Gaeumannomyces graminis Wheat
Maize , Wheat,
Sorghum
Ralstonia solanacearum Tomato and
potato
Legume crops Streptomyces scabis Potato
Ground nut Meloidogyne incognita Tomato
Effect of short term rotation on some pathogens

14. Date of sowing
 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.

15. PLANT NUTRIENT AND DISEASE CONTROL
• All essential plant nutrients influence the health of
plants and their susceptibility to disease. Plants
suffering a nutrient stress will be more susceptible
to diseases, while adequate crop nutrition makes
plants more tolerant of or resistant to disease.
• The nutrient status of the soil and the use of
particular fertilizers and amendments can have
significant impacts on the pathogen’s environment.

16. • One of the most widely recognized associations
between fertility management and a crop disease is
the effect of soil pH on potato scab.
• Potato scab is more severe in soils with pH levels
above 5.2. Below 5.2 the disease is generally
suppressed.
• Sulfur and ammonium sources of nitrogen acidify
the soil, also reducing the incidence and severity of
potato scab.

17. • Fungi penetrate the surface cells (epidermis), by passing
between the cells or through them. The cell walls present
a physical resistance to the fungus and stronger cell walls
can prevent the infection. Certain nutrients, like Calcium,
play a major role in the ability of the plant to develop
stronger cell walls and tissues.
Example
• Bacteria invade the plant tissue through wounds, sucking
insects and through the stomata. Then they spread within
the intercellular spaces. The bacteria release enzymes
that dissolve the plant tissue. Calcium is known in its
ability to inhibit such enzymes.

18. How can mineral nutrition prevent plant disease?
Mineral nutrition can affect two primary
resistance mechanisms:
A) Formation of
mechanical
barrier (eg.
Thickness of cell
wall )
B ) Synthesis of natural
defence compounds
(eg: phytoalexins ,
antioxidants and
flavanoids)

19. NUTRIENT SUPPRESSING DISEASE CROPS
Calcium 1)Clubroot
2)Fusarial wilt
3)Damping off
1) Curcifiers
2) Tomato,Watermelon and
cotton.
3) Peanut
,Soybean,Pepper,Tomato,
onion,Bean and Wheat.
Nitrate Fusarium wilt Tomato,Celery, crysanthimum and
Carnation.
Sulfer Scab Potato
Pottassium Verticillum wilt Cotton
Phosphate Fusarial wilt Cotton and Muskmelon
EFFECT OF NUTRITION IN PLANT DISEASE SUPPRESSION

20. COMPOST AND DISEASE SUPPRESSION
Compost encourages
healthy plants that are
better equipped to fight
off disease and increase
in yield are often an
added benefit of
improving soil and
plant health.

21. HOW DOES COMPOST SUPPRESS DISEASE?
• Adding compost to soil improves soil physical and
chemical properties and increases the number and
diversity(different types) of bacteria and fungi in soil.
• Root rots caused by Pythium and Phytophthora are generally
suppressed by the high numbers and diversity of beneficial
microbes found in the compost.

22. Vegetable Pathogen/Disease Treatment Comments
Alfalfa
.
“Clover tiredness” Four years of treating fields
with high-quality compost
Stand thickness and yield doubled,
weeds crowded out .
Barley/Wheat Drysiphe graminis/
Powdery mildew
Compost added to soil. Disease incidence suppressed 95%
when 1:1 soil:compost mixes used
.
Beans
(CA blackeye
No. 5)
Rhizoctonia sp. Compost added to soil
at varying rates (36-72
tons/acre).
Disease reduced 80% in areas with
highest compost rates, 40% where
intermediate rates applied. Control
plots yielded 75 bushels/acre,
compost plots yielded 200 bu/acre
Soybeans . Phytophthora sp 40 tons of compost per
acre.
Control achieved
Compost Treatment and Disease Management

23. Vegetable Pathogen/Disease Treatment Comments
Cucumber Sphaerotheca sp./
Powdery mildew
Young cucumber plants
grown in soil/compost
mix of variable rates.
1:1 soil:compost mix
decreased PM by 20% over
control; 1:3 mix decreased
infection by 40%
Pea
(Pisum
sativum)
Pythium
sp./Damping off
Seed treatment; seeds
soaked in dilute
compost extract, dried
before sowing.
Peas seed-treated with
compost extract
germinated significantly
better than untreated seed
in soil artificially inoculated
with Pythium ultimum
Peppers Phytophthora sp. 40 tons of compost per
acre.
Compost in combination
of hilling plant rows is best
practice to reduce
Phytophthora

24. Management of top soil
1. Covering of soil with organic residue helps in
reducing plant diseases ,but it should be unrelated
material to the host’
2. Shaping the top soil into ridges will be helpful to
keeping the soil dry which is in direct contact with
collar region it help to reduce the pathogens like
sclerotium rolfsii, pythium fruit rot and sclerotiana
sclerotium

25. Cover cropping
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.
Growing of cover crops:
 Mustard and Brassicasp (Broccoli) helps to reduce the
load of soilborne pathogens.
 Cover crops will increase soil microbial diversity by
enhancing the soil microflora.
 Create unfavorable conditions.

26. Depth of sowing:
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 .
Example : Deep sowing is advisable In case of
diseases caused by Fusarium and Rhizoctonia sp

27. 2) PHYSICAL METHODS
 It aims to eradicate the pathogen propagules. It causes
the inactivation and immobilization of the pathogen
 The physical agents used most commonly in
controlling plant diseases are temperature (high or
low), dryair,unfavorable light wavelengths, and various
types of radiation.
 With some crops, cultivation in glass or plastic
greenhouses provides physical barriers to pathogens
and their vectors and in that way protects the crop from
some diseases.
 plastic or net covering of row crops may protect the
crop from infection by preventing pathogens or vectors
from reaching the plants.

28. Soil solarization
Soil solarization is a method of heating soil by covering it with
transparent polythene sheeting during hot periods to control
soilborne diseases. The technique has been commercially
exploited for growing high-value crops in diseased soils in
environments with a hot summer (maximum daily air temperatures
regularly exceeding 35°C).
Examples include control of verticillium and fusarium diseases in
vegetable crops in Israel, control of Verticillium dahlias in
orchards in California, USA and control of chickpea and
pigeonpea wilt in India.

29. Heat sterilization
It is a process of heating up of soil . It can generally
achieved by heat produced electically than supplied by
steam or hot water
Example:
At 50°C – Nematodes and some oomycetes are killed
At 60- 70°C – most plant pathogenic bacteria and
fungi.

30. Flooding
• Flooding the field to eliminate soil borne plant
pathogen is both a physical and cultural method.
• Prolonged water logging leads to lack of oxygen and
accumulate of CO2.
Example : panama wilt of banana can be effectively
controlled by flooding for 4 -6 weeks prior to planting.

31. Two ways of disease suppression:
3) BIOLOGICAL CONTROL
By
Antagonistic
association
By
Symbiotic
association

32. Antagonistic association
Bio control agents suppress disease causing
organism in four main 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.
 Predation and parasitism of plant pathogen by bio control
agents (where beneficial microbes use pathogen as a food)

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

34. 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

35. 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.
MYCORRHIZAL FUNGI AND
DISEASE SUPPRESSION
MYCORRHIZA : consider to be an association between
fungi and root of higher plants

37. IT PROTECT THE PLANT BY:
 By providing antagonistic chemicals.
 By competing with the pathogen.
 By increasing the nutrient uptake ability of plants.
 By changing the amount and type of plant root
exudates.
 It act as a barrier for invading pathogen.

38. 1. 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.
2. 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.
EXAMPLE:

39. 4) Chemical method
 Chemical pesticides are generally used to protect plant
surfaces from infection or to eradicate a pathogen that
has already infected a plant.
 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

40. • 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.

41. • Suppressiveness is linked to the types and
numbers of soil organisms, fertility level, and
nature of the soil itself .
• The response of plants growing in the soil
contributes to suppressiveness. This is
known as “induced resistance“
• The level of disease suppressiveness is
typically related to the level of total
microbiological activity in a soil.
Suppressive soil

42. • limiting available nutrients is a key for general
suppression .
• Virtually any treatment to increase the total
microbial activity in the soil will enhance general
suppression of pathogens by increasing
competition for nutrients.

43. 5) Host Plant Resistance
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):

44. General preventive measures to restrict soil-borne
diseases occurrence
 Select resistant plant cultivars and certified disease-
free stock, then plant them at the right time of year.
 Avoid mechanical damage to plants
 Do not over-fertilize; doing so inhibits proper root
development
 Management of soil pH—raising the soil pH to 6.5–7
by using nitrate nitrogen in place of ammonical
nitrogen, for example will decrease the development of
Fusarial wilt.
 Avoid contamination of the growing medium and
purchase quality seed

45.  Avoid use of low, poorly drained areas for nursery
production
 Restrict use of machinery in infested areas,
particularly when soil is wet
 Prevent movement of soil from infested to non-
infested areas of nursery
 Avoid over watering to puddle or run-off point
 Avoid movement of infected trees within and between
nurseries

46. Conclusion
 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.
 Hopefully, the present situation, which emphasizes the use of
integrated disease management practices, will stimulate the
development of non-chemical methods of disease management to
better manage the soilborne pathogens.