Disease management

1. CROP DISEASE MANAGEMENT
AND CONSERVATION
AGRICULTURE

2. THREE MAIN GOALS ARE AT THE HEART OF THIS EFFORT
A Global Commitment to Sustainable Agriculture
Help farmers
DOUBLE YIELDS
by 2030
REDUCE inputs
required per unit of
output by 1/3
IMPROVE LIVES of farmers around
the world
Hunger and food
security
Environment &
climate change
Poverty and stable income

3. • Traditionally in India, only organic farming was practiced.
• No chemical fertilizers and pesticides were used.
• During 1950s and 1960s the ever increasing population of India
lead to a food scarcity.
• The government was forced to import food grains from foreign
countries.
• And also forced to increase a food grain production of India to
increase food security
“The Green revolution”
w as introduced in late sixties

5.  Unsustainable high yields
 Over exploitation of Natural resources
 Indiscriminate use of agricultural chemicals
Above practices for two decades resulted in deterioration of
soil health (soil sickness)
• Reduction in natural fertility of soil or Nutritional imbalances
• Disturbed natural hydrology or Ground water pollution and
depletion
• Resurgence of pests & diseases and Killing of beneficial
microbes and insects
• Destruction of soil structure and Erosion and soil loss
• Soil salinity/alkalinity

12. CA includes ICM

14. Principles of Organic Farming

15. Developmental phases of Plant Disease Management
 Limited intervention in ancient farming systems;
 Mechanical and temporal disease suppression approaches
(rogueing, ploughing, rotations).
 Widespread use of major gene resistances and pesticides
before and following the first Green Revolution.
 Integrated pest/diseases management and ecological
management emphasizing synergic effects on the economy,
society and both the agricultural and natural
environments.

16. Solution to improve healthy condition of plant population in agro-ecological system.
Sustainable plant disease management that aims at improving plant health at population
level can be achieved through a comprehensive understanding the mechanisms of plant
disease epidemics, and multi-functions of agro-ecosystems, and interactions among
biotic and abiotic conditions, marketing and societal demands. “Knowledge of disease
triangles” means plant-pathogen-environment interaction and plant population biotic
factors-abiotic factors interaction. “Ten principles” mean soil, nutrition, water, seed,
population density, plant protection, field management, farming machine technique, light
and air

17. Understanding Disease
Weather Pathogen
Crop
Disease

18. The core of Ecological plant disease management
The core of ecological plant disease management is to
manipulate the environments of host-pathogen
interactions in the favor of hosts through the balanced
application of RAER strategy:
 Resistance
 Avoidance
 Elimination
 Remedy

19. Organic Disease Management
1. Importance of diseases varies among crops,
locations
2. Prevention is the best strategy
3. Options are fewer once disease is present
4. Management requires an integrated
[systems] approach
Approach
Target overall plant/crop health rather than a
specific disease

20. The Rational management of plant disease:
Changes in the philosophy of plant disease Management: shift the
focus of plant disease management from managing pathogens (or insect
vectors) to managing host plants and from the sole goal of high productivity
to multiple goals of high yield, efficiency, good quality and safety.
Ecological management of plant disease: The key to sustainable plant
disease management is to establish an agro-ecological system that is
favorable to plant growth and development at the population level and
adverse to pathogen evolution and epidemic development based on
interactions among plants, pathogens, vectors and environments
This integrated approach shows great promise in overcoming the problems
and challenges associated with current strategies of plant disease
management to optimize its economic, ecological and social benefits.

21. Conventional v/s Organic
How disease control is different for the organic grower ?

22. Control strategies can be divided into two groups based on their effect
on the development of resistance to the control measure by the
pathogen:
1. Eradicative control measures — designed to eliminate the entire
pathogen population – e.g.: protection by pesticides, vertical or
complete resistance - These tend to select for resistant variants of the
pathogen.
2. Management control measures — designed to reduce the pathogen
population by destroying a portion of the population – e.g.: horizontal or
partial resistance, biological or antagonism, cultural practices, exclusion
through quarantine, inspection and certification - These do not apply
heavy selection pressure to the pathogen.
* Of the two, we prefer to use management strategies.

23. Four basic types of management measures:
a. Biological control
b. Cultural control
c. Legislative and regulatory control
d. Chemical control

24. Manipulation of biotic entities; host and antagonistic
microorganisms
1. Host resistance - control based on the genes and the
resistance mechanisms they control
a. Van der Plank described two types of resistance (1960s;
these are the "classics‘’):
i. Vertical resistance — effective against some, but not all, races
of a pathogen; decreases the effective amount of incoming
inoculum (avirulent races can't infect), but does not reduce the
rate of disease development (virulent races are not affected)
ii. Horizontal resistance — effective against all races of the
pathogen; decreases the rate of disease development for all
races

26. b. Resistance has been defined in many other ways since
Van der Plank, including systems based on:
epidemiologic effects, number of genes involved,
how long the resistance lasts under field conditions;
additional terms are:
i. tolerance — plants are diseased, but they do not
yield less than healthy plants
ii. induced resistance — a normally susceptible plant
treated with an avirulent strain of a pathogen
gives a resistant reaction when challenged later
with a strain that is virulent

27. 2. Antagonists — control using microorganisms that inhibit the
growth, development or reproduction of pathogens
Four types of activity:
i). Antibiosis — inhibition of pathogen through antibiotics produced by the
antagonist - examples: streptomycin (antibacterial, from actinomycete),
penicillin (antibacterial, from fungus)
ii). Competition — two organisms attempt to utilize the same limiting factors
(nutrients, oxygen); supply not large enough to support both antagonist
and pathogen
iii). Amensalism — antagonist makes the environment unsuitable for the
pathogen (modifies pH, temperature, moisture)
iv). Parasitism & predation — antagonist directly attacks the pathogen e.g.:
nematode-trapping fungi

28. BIOLOGICAL METHODS
Aims to conserve and use natural enemies
INTRODUCTION OF BIO-AGENTS
– Trichoderma spp. and Pseudomonas for controlling soil
borne diseases in pulses and vegetables
• Aspergillus niger (AN 27) seed treatment @ 5g per kg of
seed check the Fusarium wilt in many crops.
• Use of NPV’s for controlling pod borer
• Tricograma for management of Parthenium
GENETIC APPROACH
• Use of resistant varieties helps in managing
many plant diseases like rust, smut etc.
e.g. PBW 644, PBW 725, HD-3086, HD-3226,
HD-3237, WH-1105, WH-1142 etc.

29. Cultural (physical) control — manipulation of the environment
There are many types of cultural control. Few selected examples:
1. Crop rotation — rotate crops and varieties over seasons to reduce
pathogen inoculum levels * This is probably the most widely employed
control measure in agriculture! e.g.: rotate soybean with corn to control
soybean cyst nematode
2. Selection of planting date or planting location — choose a time/place
favorable for the host, rather than the pathogen: avoid pathogen or its
vector example: (time) plant cotton late to control damping-off caused
by Pythium (warm soil)
3. Seeding rate and canopy density — adjust within-row and between-row
spacing to open the canopy and reduce diseases that spread in the
humid, protected canopy environment

30. Cultural (physical) control — manipulation of the environment
4. Irrigation
a. Pathogens can be spread in irrigation water or favored by wet soils-e.g.: late blight
(Phytophthora)
b. Pathogens can be controlled by flooding – e.g.: Fusarium wilt of banana
5. Control insects and weeds — insects vector viruses and other pathogens; weeds
serve as alternate hosts for pathogens or vectors and increase canopy density
6. Sanitation -- keep area free of diseased plant material by pruning diseased
branches (fireblight), plowing under or burning debris, washing and sterilizing
harvesting and processing equipment (Rhizopus soft rot); poor sanitation
contributed to the late blight outbreak that caused the Irish famine
7. Heat or refrigeration -- hot air, hot water, or steam treatments are used to kill
pathogens in seed or propagation materials; harvested fruits and vegetables are
kept refrigerated
8. Biofumigation—practice of using plant based chemicals to supress soil borne
pathogens. Brassica is widely utilized for biofumigant activity and it improves soil
structure, assists in weed control, reduces soil erosion and provides organic
matter

31. CULTURAL METHODS
• Tillage
– Deep ploughing is beneficial for
exposing the eggs and inoculum which
is picked by birds or may die because
of desiccation.
– Deep ploughing also helps in checking
soil borne pathogens e.g. Sclerotinia
sclerotiorum causing stem rot
disease.
• Clean seeds
– Use of clean seeds helpful in
managing many diseases e.g. False
smut of paddy, ear cockle disease in
wheat.
– Removal of balls/galls

32. • Water management
– Flooding of fields is recommended for reducing the attack of cut
worms, army worms and termite etc.
– Alternate wetting and drying is helpful in management of bacterial
blight in paddy.
• Fertilizers management
– Balance use of fertilizer is helpful in management of Brown spot
and Bacterial blight in paddy.
• Spacing
– Proper crop spacing reduces the attack of many Soil borne
pathogens as it avoids the moist chamber effects e.g. Wilt and stem
rot incidence in grams.
• Crop rotation
– Crop rotation with non preferred host helps in management of many
insect pests and diseases especially Soil borne pathogens

33. Effect of N level on disease severity
Nitrogen is the most important nutrient for plant growth and there is an extensive
literature about the effect of N on diseases, because its role in disease resistance is
quite easily demonstrated

34. Effect of Phosphorus level on
disease severity
• Phosphorus is the second most commonly applied nutrient in most
crops and is part of many organic molecules of the cell deoxyribonucleic
acid (DNA), ribonucleic acid (RNA), adenosine triphosphate (ATP) and
phospholipids) and is also involved in many metabolic processes in the
plant and also in the pathogen.
• Its role in resistance is variable and seemingly inconsistent. P has been
shown to be most beneficial when it is applied to control seedlings and
fungal diseases where vigorous root development permits plants to
escape disease.
• Phosphate fertilization of wheat can have a significant effect and almost
eliminate economic losses from Pythium root rot. Similarly, in corn P
application can reduce root rot.
• A number of other studies have shown that P application can reduce
bacterial leaf blight in rice, downy mildew, blue mold, leaf curl virus
disease in tobacco, Pod and stem blight in soybean, yellow dwarf virus
disease in barley, brown stripe disease in sugarcane and blast disease in
rice

35. Effect of K level on disease
severity
• Potassium decreases the susceptibility of host plants up to the
optimal level for growth further increase in resistance which
can be achieved by increasing the supply of K and its contents
in plants
• The high susceptibility of the K-deficient plant to parasitic
disease is due to the metabolic functions of K in plant
physiology.
• Also, K may promote the development of thicker outer walls in
epidermal cells, thus preventing disease attack.

36. Effect of K level on disease severity
of several diseases

37. Powdery mildew (Erysiphe cichoracearum) with an extensive
growth of white, powdery fungal mycelium on the upper leaf
surface of sunflower (Helianthus annuus).
Damage caused by safflower rust (Puccinia carthami).
Light gray lesions with a dark border in sugar beet (Beta
vulgaris) leaves caused by Cercospora beticola.
Lesions caused by bacterial blight (Xanthomonas
campestris pv malvacearum) in cotton (Gossypium hirsutum).

38. • Intercropping
– Intercropping groundnut with bajra reducing the incidence of thrips,
jassids & leaf minor.
• Time of sowing
– Early sowing of rice i.e. early June is helpful in protecting it from
borer.
– Early sowing of gram results in wilt disease
• Field sanitation
– Removal and destruction crop residue manages many diseases
eg;Potato blight.
– Clipping of lower leaves in sarson helps in reduction of Alternaria
blight
– Deep burial of trash recommended for diseases on crop debris eg;
Blackleg or Club root of crucifers

39. Soil Solarization
• Soil solarization is a method of controlling soil
borne pests and pathogens by raising the
temperature of the soil through application of
transparent polyethylene sheet to a moist soil
surface.

40. A flow chart explaining multicital effect of solarization and
integrated management of crop health

41. Soil Fertility and Crop Nutrient
Residue Management
Cropping practices will improve soil
organic matter and reduce pest
pressure.
Mulching
Cover Crop

44. Improve Soil Quality
• Reduce diseases by soilborne pathogens
• Enhance composition of “beneficial” organisms
– Increase the abundance and diversity of the soil
microbial community
• Increase soil organic matter
• Cover crops/Green manures
• Composts/Animal manures

45. Effects of Compost on Plant Health
• Increases soil suppressiveness to diseases
• Induces disease resistance (“healthier plants”)
• Improves soil tilth
• Improves soil moisture-holding capacity

46. Crop Rotation
Continuous cropping most likely to allow
disease build up
Back-to-back cereals NOT recommended
Minimum of 3 years between crops to
encourage total breakdown of crop residue
that can harbour disease material, spores,
etc.
Specific diseases can require longer
periods

50. 1. Quarantine — detention and associated practices for preventing the
entry of diseased materials or pathogens into an area; relatively
inexpensive; can be at federal or state level.
a. APHIS (Animal and Plant Health Inspection Service) — agency
within USDA that runs:
i. PPQ (Plant Protection and Quarantine) — agency responsible
for federal quarantines -established by the Plant Quarantine Act
(1912
b. Pest and Disease Survey — national database; all pests on major crops in
each state
c. Action programs -- eradicate or contain pests that get past quarantine
worked for: citrus canker .

51. 1. Quarantine —
2. Inspection and certification programs — state level;
plants/seeds grown under conditions unfavorable for
pathogens and are inspected to be sure that pests are not
transported along with packing material
3. Pesticide labeling and applicator certification — these
activities are under the control of the EPA (Environmental
Protection Agency)

52. Permitted substances
 Number of products can be used
 Can be costly so mostly applied to fruit and
vegetable crops
 Copper sulphate used to control bacterial
diseases- Bacterial blight on beans
 Sulphur products help reduce mildew infections
 Vinegars, compost teas, seaweed products
available
 Always check if product use permitted ?

53. Name Source Trade names Uses
Strobilurin Strobilurus tenacellus Amitsar,
Flint, Sovran
Headline
Fungicide
Blasticidin S Streptomyces
griseochromogens
Bla-S, Cytovirin Bactericide
Rotenone Lonchocarpus utilis Chem-Fish,
Cuberol, Fish Tox,
Noxfire, Rotacide,
Sinid, Tox-R
Pisicide
Kasugamycin Streptomyces
kasugaensis
Kasumin Bactericide
Griseofulvin Penicillium
griseofulvum
Dermonor, Fluvin,
Fungivin, Geovin,
Gris O.D
Fungicide
Pesticides of Natural Origin

54. Botanical & Application Method Pathogen Controlled
Dhdatura water extract (5%) F. oxysporum f. sp. zingiberi
Calotropis (5%)
Neem leaf extract (2:5) Alternaria
Neem oil (4l oil +1000l water + 1 kg detergent)
Neem (leaf extract 2:10 w/v) Fruit rot of cucurbits
Neam cake (@ 500 g/m2) Soil borne disease of ginger
Aloevera leaf extract (1:10)
Calotropis
Cassia auriculata
Diseases of onion
Botanical Pesticides

55. Commercial Botanicals
 Dasparni (Leaves fermented in cow urine)
-Foliar spray @5-10%
 Azadirectin 0.03% (Neem oil based pesticide)
 Zetron (Acaciasin1%+Hexuronic Acid2%)
-Foliar Spray @ 0.5% against Tomato fruit rot
 Wanis 20EC(Cymbopogan extract)
-Foliar Spray @ 0.5%
 Safe

56. Commercial Botanical Pesticides
 Biogrill (Alkaloid18%+Surfectant82%)
-Host defense modulator/Antiviral
 Biosmart (Botanical extract16.4%+Surfectant83.6% )
-Biofungicides for Leaf spot, blight, DM and leaf curl
 Velvet
-Natural PR protein synthesizing agent/antviral
 Tafacin & Allexin (Live cells Pvt. Ltd.)
-Natural plant resistance activator

57. Synthetic Substances allowed for
use in Organic Farming
• Copper fixed- Copper hydroxide, copper oxide, copper
oxychloride- must be used in a manner that minimizes
accumulation of copper in soil, and shall not be used as
herbicide
• Copper sulfate- must be used in a manner that minimizes
accumulation of copper in soil
• Hydrated lime
• Hydrogen peroxide
• Lime sulfur
• Horticultural oils
• Peracetic acid- for fire blight
• Potassium bicarbonate
• Elemental sulfur
• Streptomycin- for fire blight control only
• Tetracycline- for fire blight control only

58. CONCLUSION
• Through natural disease management
practices we can grow crops, following the
natural law and adopt Natural Organic and
Biological Farming Systems that :
 Self sustaining,
 Cost effective and
 Environment friendly.

59. Thank You