Principles of Integrated Disease Management (2).pdf

Principles of Integrated Disease Management by Ranjeet Maurya

1. Principles of Integrated Disease Management
3
rd
semester
Created by – Ranjeet Kumar Sir
Lecture - 1
Categories of Plant Diseases
Plant diseases can be broadly categorized based on the type of pathogen or cause:
1. Fungal Diseases:
o Caused by: Fungi and fungal-like organisms.
o Examples: Powdery Mildew, Rust, Blight, Root Rot.
o Characteristics: Fungi often thrive in warm, moist conditions and can affect various
parts of the plant, including leaves, stems, and roots.
2. Bacterial Diseases:
o Caused by: Bacteria.
o Examples: Bacterial Wilt, Fire Blight, Bacterial Leaf Spot.
o Characteristics: Bacterial infections often cause wilting, spots, or galls and can spread
through water, soil, and contaminated tools.
3. Viral Diseases:
o Caused by: Viruses.
o Examples: Tobacco Mosaic Virus (TMV), Tomato Yellow Leaf Curl Virus, Cucumber
Mosaic Virus.
o Characteristics: Viral diseases typically cause mottling, discoloration, and stunted
growth and are often spread by insect vectors like aphids or by contact.
4. Nematode Diseases:
o Caused by: Nematodes (microscopic worms).
o Examples: Root Knot Nematodes, Cyst Nematodes.
o Characteristics: Nematode infestations often lead to root damage, resulting in stunted
growth, wilting, and reduced yields.
5. Phytoplasma and Spiroplasma Diseases:

2. o Caused by: Phytoplasmas and Spiroplasmas (bacteria-like organisms).
o Examples: Aster Yellows, Lethal Yellowing.
o Characteristics: These diseases often cause yellowing, phyllody (where flowers turn
into leaf-like structures), and stunting of plants.
6. Parasitic Plant Diseases:
o Caused by: Parasitic plants.
o Examples: Dodder, Mistletoe, Broomrape.
o Characteristics: These parasites attach to the host plant, extracting water and nutrients,
which can lead to the decline of the host.
7. Abiotic Diseases:
o Caused by: Non-living factors such as environmental stress, nutrient deficiencies, or
chemical injuries.
o Examples: Drought stress, Frost damage, Nutrient deficiencies (e.g., Iron chlorosis).
o Characteristics: Abiotic diseases do not spread from plant to plant and often result from
unfavorable growing conditions.
Integrated Disease Management (IDM) in Plants
Integrated Disease Management (IDM) in plants is a strategy that involves using a
combination of practices and tools to manage plant diseases in an environmentally and
economically sustainable way. IDM is based on the principles of Integrated Pest Management
(IPM) but focuses specifically on plant diseases.
Principles of IDM in Plants
1. Prevention:
o Focus: Preventing the occurrence of diseases through practices such as selecting resistant
plant varieties, using certified disease-free seeds, and practicing crop rotation.
o Examples: Choosing cultivars resistant to specific pathogens, sanitizing tools and
equipment, and ensuring proper field drainage to avoid waterlogging.
2. Monitoring and Early Detection:
o Focus: Regularly monitoring plants for signs of disease and identifying problems early to
prevent their spread.

3. o Examples: Regular field scouting, using disease forecasting models, and employing
diagnostic tests to detect pathogens.
3. Cultural Practices:
o Focus: Modifying cultivation practices to reduce disease risk.
o Examples: Adjusting planting times to avoid peak periods of disease pressure, spacing
plants to improve air circulation, and using mulches to reduce soil-borne pathogens.
4. Biological Control:
o Focus: Utilizing natural enemies or beneficial organisms to manage plant diseases.
o Examples: Applying biocontrol agents like Trichoderma or Bacillus species to suppress
soil-borne pathogens, using beneficial insects to control disease vectors, and promoting
healthy soil microbiomes.
5. Chemical Control:
o Focus: Using fungicides, bactericides, or nematicides as part of a broader IDM strategy,
and only when necessary.
o Examples: Applying chemicals in a targeted manner to avoid resistance, using systemic
fungicides to protect plants during vulnerable stages, and following proper application
protocols.
6. Genetic Resistance:
o Focus: Breeding and using plant varieties that are resistant or tolerant to specific
diseases.
o Examples: Growing genetically resistant cultivars of wheat to combat rust or using
grafted plants that are resistant to root diseases.
7. Legislation and Quarantine:
o Focus: Implementing and adhering to regulations that prevent the spread of plant
diseases.
o Examples: Enforcing quarantine measures for infected areas, regulating the movement of
plant materials, and adhering to international phytosanitary standards.
8. Education and Training:
o Focus: Educating farmers, extension workers, and the agricultural community on IDM
practices.
o Examples: Conducting workshops on disease identification, providing training on safe
chemical use, and distributing guidelines on best management practices.

4. Tools of IDM in Plants
1. Disease-Resistant Varieties: Development and deployment of crop varieties that are
resistant or tolerant to specific pathogens.
2. Crop Rotation: Changing the types of crops grown in a field over time to break disease
cycles.
3. Sanitation: Cleaning tools, equipment, and plant debris to prevent the spread of
pathogens.
4. Biocontrol Agents: Introduction or encouragement of beneficial microorganisms that
inhibit or destroy pathogens.
5. Chemical Applications: Targeted use of fungicides, bactericides, and other chemical
controls, following guidelines to avoid resistance and environmental harm.
6. Soil Management: Improving soil health through organic amendments, cover cropping,
and proper irrigation to reduce soil-borne diseases.
7. Physical Barriers: Using row covers, mulches, or other physical barriers to protect
plants from pathogen exposure.
8. Diagnostic Tools: Use of molecular diagnostics, disease forecasting models, and remote
sensing technologies to monitor and predict disease outbreaks.
Lecture -2
Introduction to Integrated Disease Management (IDM) in Plants
Integrated Disease Management (IDM) in plants is a holistic approach that combines multiple
strategies to prevent, monitor, and control plant diseases. Unlike traditional methods that may
rely heavily on chemical treatments, IDM incorporates a variety of practices—including cultural,
biological, chemical, and environmental controls—into a comprehensive plan that reduces
disease impact while promoting sustainability. IDM aims to optimize plant health, minimize
environmental impact, and ensure economic viability for farmers.
History of Integrated Disease Management in Plants

5. The concept of IDM has evolved over several decades, particularly in response to the challenges
posed by the overuse of chemical pesticides in agriculture. During the Green Revolution in the
mid-20th century, the widespread use of chemical inputs, including pesticides, led to significant
increases in crop yields. However, this approach also brought about unintended consequences,
such as the development of pesticide-resistant pathogens, environmental pollution, and harm to
non-target organisms.
In response to these issues, the 1960s saw the emergence of Integrated Pest Management
(IPM), a strategy that emphasized the use of multiple control methods to manage pests in an
environmentally and economically sustainable manner. IDM emerged as an extension of IPM,
with a specific focus on managing plant diseases. Over time, IDM has become a key component
of sustainable agriculture, integrating modern scientific advances with traditional farming
practices.
Importance of Integrated Disease Management in Plants
IDM is critical for several reasons:
1. Sustainability: IDM promotes the sustainable use of resources by reducing the reliance
on chemical pesticides and encouraging environmentally friendly practices. This helps
preserve ecosystems and biodiversity.
2. Resistance Management: By integrating multiple disease control methods, IDM reduces
the likelihood of pathogens developing resistance to treatments, thereby maintaining the
effectiveness of control measures over time.
3. Economic Viability: IDM can be more cost-effective in the long term, as it reduces the
need for expensive chemical treatments and minimizes crop losses due to disease.
4. Environmental Protection: IDM supports the protection of natural resources by
minimizing the use of harmful chemicals and promoting practices that improve soil
health and reduce pollution.
5. Food Security: By managing plant diseases more effectively, IDM contributes to stable
and increased crop yields, thereby supporting global food security.
Concepts of Integrated Disease Management in Plants

6. 1. Holistic Approach: IDM considers the entire agricultural ecosystem, including the
interactions between plants, pathogens, and the environment. This approach helps in
designing effective, long-term disease management strategies.
2. Prevention First: IDM emphasizes preventive measures to reduce the likelihood of
disease outbreaks, such as selecting resistant plant varieties and improving soil health.
3. Integration of Methods: IDM integrates various disease control methods, including
cultural, biological, chemical, and environmental practices, into a coordinated strategy.
4. Monitoring and Early Detection: Regular monitoring of crops for signs of disease
allows for early detection and timely intervention, which is crucial for preventing the
spread of diseases.
5. Adaptability: IDM strategies are flexible and can be adapted to changing conditions,
such as climate variations, new disease strains, or shifts in agricultural practices.
Principles of Integrated Disease Management in Plants
1. Prevention and Exclusion:
o Focus: Preventing the introduction and spread of diseases by using certified
disease-free seeds, practicing crop rotation, and implementing quarantine
measures.
o Examples: Selecting resistant plant varieties, ensuring proper sanitation of tools
and equipment, and practicing crop rotation to disrupt disease cycles.
2. Cultural Controls:
o Focus: Modifying agricultural practices to create conditions that are less
favorable for disease development.
o Examples: Adjusting planting dates to avoid peak disease periods, using proper
spacing to improve air circulation, and managing irrigation to avoid excessive
moisture.
3. Biological Control:
o Focus: Utilizing natural predators, parasites, or beneficial microorganisms to
control plant pathogens.
o Examples: Applying biocontrol agents like Trichoderma to suppress soil-borne
pathogens or encouraging beneficial insects that prey on disease vectors.

7. 4. Chemical Control:
o Focus: Using fungicides, bactericides, or other chemical treatments judiciously
and as part of a broader IDM strategy.
o Examples: Applying targeted fungicides during critical growth stages and
following integrated pest management (IPM) guidelines to minimize resistance.
5. Genetic Resistance:
o Focus: Breeding and using plant varieties that are resistant or tolerant to specific
diseases.
o Examples: Growing resistant cultivars of tomatoes to combat Fusarium wilt or
using grafted plants with resistant rootstocks.
6. Legislation and Quarantine:
o Focus: Implementing and adhering to regulations that prevent the spread of plant
diseases across regions.
o Examples: Enforcing quarantine measures for affected areas and adhering to
international phytosanitary standards.
7. Education and Training:
o Focus: Educating farmers, extension workers, and the agricultural community on
IDM practices.
o Examples: Conducting workshops on disease identification and management,
providing training on safe chemical use, and distributing guidelines on best
practices.
Tools of Integrated Disease Management in Plants
1. Disease-Resistant Varieties: Development and deployment of crop varieties that are
resistant or tolerant to specific pathogens.
2. Crop Rotation: Alternating different crops in the same field over successive seasons to
disrupt the life cycles of pathogens.
3. Sanitation: Cleaning tools, equipment, and removing plant debris to prevent the spread
of pathogens.
4. Biocontrol Agents: Introducing or encouraging beneficial microorganisms, such as
Trichoderma, Bacillus, or mycorrhizal fungi, that inhibit or destroy pathogens.

8. 5. Chemical Applications: Targeted use of fungicides, bactericides, and other chemical
controls, applied according to guidelines to minimize resistance and environmental
impact.
6. Soil Management: Improving soil health through organic amendments, cover cropping,
and proper irrigation practices to reduce soil-borne diseases.
7. Physical Barriers: Using row covers, mulches, or other physical barriers to protect
plants from pathogen exposure.
8. Diagnostic Tools: Utilizing molecular diagnostics, disease forecasting models, and
remote sensing technologies to monitor and predict disease outbreaks.

Lecture -3
Economic Importance of Plant Diseases
Plant diseases have a profound economic impact on agriculture, affecting crop yields, quality,
and marketability. The economic importance of plant diseases can be summarized as follows:
1. Yield Losses:
o Impact: Plant diseases can cause significant reductions in crop yields, leading to lower
productivity and economic losses for farmers. Some diseases, like rusts or blights, can
devastate entire fields if not properly managed.
o Example: Late blight in potatoes, caused by Phytophthora infestans, led to the Irish
Potato Famine in the 19th century, resulting in massive crop failure and economic
collapse.
2. Quality Reduction:
o Impact: Even if the overall yield is not severely affected, plant diseases can reduce the
quality of the produce, making it less marketable. Diseased crops may have blemishes,
discoloration, or deformities that reduce their market value.
o Example: Apple scab, caused by Venturia inaequalis, can cause blemishes on fruit,
reducing its commercial value in fresh markets.
3. Increased Production Costs:

9. o Impact: Farmers often need to invest in additional inputs, such as pesticides, fungicides,
or resistant crop varieties, to manage plant diseases. These added costs can reduce profit
margins.
o Example: The cost of managing Fusarium wilt in banana plantations includes frequent
applications of fungicides and the use of resistant cultivars, which increases production
costs.
4. Trade Restrictions:
o Impact: The presence of certain plant diseases can lead to trade restrictions or quarantine
measures, limiting the export potential of affected crops. This can result in economic
losses for producers and exporters.
o Example: Citrus greening disease (Huanglongbing) has led to strict quarantine
regulations and trade restrictions on citrus products from affected regions.
5. Supply Chain Disruptions:
o Impact: Large-scale disease outbreaks can disrupt supply chains, leading to shortages of
raw materials for food processing industries, price fluctuations, and food insecurity.
o Example: The outbreak of wheat stem rust, caused by Puccinia graminis, in major
wheat-producing regions can lead to global supply chain disruptions, affecting food
prices worldwide.
6. Long-Term Soil Health Decline:
o Impact: Certain soil-borne diseases can degrade soil health over time, reducing the land's
productivity and leading to long-term economic consequences.
o Example: Continuous cropping of tomatoes in the same field can lead to the buildup of
soil-borne pathogens like Verticillium and Fusarium, reducing soil fertility and crop
yields over time.
Methods of Detection and Diagnosis of Plant Diseases
Accurate detection and diagnosis of plant diseases are crucial for effective management. Various
methods are employed to identify diseases in plants, ranging from traditional visual inspections
to advanced molecular techniques.
1. Visual Inspection and Field Diagnosis
 Method:

10. o Traditional method where symptoms like leaf spots, wilting, discoloration, and
mold are observed by trained personnel.
o Field diagnosis relies on comparing observed symptoms with known disease
symptoms to identify the pathogen.
 Advantages:
o Quick and inexpensive.
 Disadvantages:
o Subjective and can be inaccurate, especially for diseases with similar symptoms
or in the early stages of infection.
 Tools:
o Hand lenses, field guides, and diagnostic keys.
 Example:
o Identifying powdery mildew on crops based on the characteristic white, powdery
spots on leaves.
2. Microscopic Examination
 Method:
o Plant tissues are examined under a microscope to identify the presence of
pathogens like fungi, bacteria, or nematodes.
o Fungal spores, bacterial colonies, or nematode structures can often be seen under
magnification.
 Advantages:
o Provides more detailed information about the pathogen.
 Disadvantages:
o Requires specialized equipment and expertise.
 Tools:
o Compound microscopes, staining agents.
 Example:
o Detecting nematodes in root samples by observing their microscopic structures.

11. 3. Culturing Techniques
 Method:
o Pathogens are isolated from plant tissues and cultured in specific growth media to
identify them based on their morphology and growth characteristics.
o Commonly used for bacterial and fungal pathogens.
 Advantages:
o Allows for precise identification and further study of the pathogen.
 Disadvantages:
o Time-consuming and requires sterile conditions.
 Tools:
o Petri dishes, growth media (e.g., potato dextrose agar), incubators.
 Example:
o Isolating and identifying Fusarium species from infected plant roots by culturing
them in a lab.
4. Serological Methods (e.g., ELISA)
 Method:
o Use of antibodies to detect specific proteins or antigens associated with a
particular pathogen.
o Enzyme-Linked Immunosorbent Assay (ELISA) is one of the most common
serological tests.
 Advantages:
o High specificity and sensitivity, suitable for large-scale screening.
 Disadvantages:
o Requires specific antibodies and equipment.
 Tools:
o ELISA plates, spectrophotometers.
 Example:
o Detection of viruses like Tobacco Mosaic Virus (TMV) in plant tissues using
ELISA.

12. 5. Molecular Techniques (e.g., PCR)
 Method:
o Polymerase Chain Reaction (PCR) and other DNA-based techniques are used to
detect the genetic material of pathogens, allowing for highly specific
identification.
 Advantages:
o Extremely sensitive and specific, can detect pathogens at low levels and in early
stages.
 Disadvantages:
o Requires specialized equipment and expertise.
 Tools:
o PCR machines, gel electrophoresis, DNA extraction kits.
 Example:
o Detecting Phytophthora infestans (cause of late blight) in potatoes using PCR to
amplify specific DNA sequences.
6. Immunofluorescence
 Method:
o Uses fluorescent-labeled antibodies to detect specific pathogens in plant tissues.
The pathogen's presence is indicated by fluorescence under UV light.
 Advantages:
o High specificity and allows for the localization of pathogens within tissues.
 Disadvantages:
o Requires fluorescence microscopy and specific reagents.
 Tools:
o Fluorescence microscope, fluorescent antibodies.
 Example:
o Identifying bacterial pathogens like Xanthomonas in infected leaf tissues using
immunofluorescence.

13. 7. Remote Sensing and Imaging
 Method:
o Use of aerial or satellite imagery, drones, and multispectral cameras to detect
disease symptoms in crops over large areas. Differences in reflectance can
indicate stress caused by diseases.
 Advantages:
o Allows for large-scale monitoring and early detection of disease outbreaks.
 Disadvantages:
o Requires advanced technology and data analysis skills.
 Tools:
o Drones, multispectral cameras, remote sensing software.
 Example:
o Using NDVI (Normalized Difference Vegetation Index) to detect areas of a crop
field affected by disease.
8. Biochemical Tests
 Method:
o Involves testing plant tissues for specific biochemical markers, such as toxins or
enzymes produced by pathogens.
 Advantages:
o Can provide insights into the metabolic activity of the pathogen.
 Disadvantages:
o May require complex lab procedures and specialized knowledge.
 Tools:
o Chromatography, mass spectrometry.
 Example:
o Detecting mycotoxins produced by fungal pathogens in grains using
chromatography.

14. Lecture – 4
Economic Injury Level (EIL) and Economic Threshold Level (ETL) in
Integrated Disease Management (IDM)
1. Economic Injury Level (EIL):
The Economic Injury Level (EIL) is the lowest population density of a pest or disease that will
cause economic damage—i.e., the cost of managing the pest equals the revenue loss due to the
damage it causes. In simpler terms, it is the point where the cost of damage exceeds the cost of
control.
Calculation of EIL: The EIL can be calculated using the following formula:
EIL=
C
V×I×D×K

Where:
 C = Cost of control measures (e.g., pesticide application, labor)
 V = Market value of the crop per unit area
 I = Injury units per pest or disease unit (e.g., damage per insect or disease severity per
unit area)
 D = Damage per unit injury (the relationship between pest population and yield loss)
 K = Proportionate reduction in pest or disease population achieved by the control
measure
2. Economic Threshold Level (ETL):
The Economic Threshold Level (ETL), also known as the action threshold, is the pest or disease
density at which control measures should be applied to prevent an increasing population from
reaching the EIL. The ETL is typically set below the EIL to ensure that the pest or disease does
not exceed the level where economic damage occurs.

15. Importance of ETL in IDM:
 Preventive Measure: ETL acts as a preventive measure, signaling when to initiate
control actions before economic losses occur. This helps in minimizing unnecessary use
of pesticides or other control measures, thus reducing costs and environmental impact.
 Sustainability: By following ETL guidelines, growers can adopt more sustainable pest
and disease management practices, focusing on long-term control strategies rather than
just reactive measures.
 Resource Efficiency: Utilizing ETL ensures that resources (e.g., labor, chemicals) are
used efficiently, only when necessary, which also contributes to reducing the overall cost
of production.
3. Dynamics of EIL and ETL:
 Fluctuations: EIL and ETL are not static; they can change based on factors such as crop
value, environmental conditions, pest or disease virulence, and the effectiveness of
control measures.
 Decision-Making: The dynamic nature of EIL and ETL requires regular monitoring of
pest populations and disease incidence to make timely and accurate decisions regarding
control measures.
 Adaptation: Integrated Disease Management (IDM) strategies must be flexible to adapt
to changing EIL and ETL values, ensuring that control measures remain effective and
economically viable.
Lecture -5
Host plant resistance, cultural, mechanical, physical, and legislative
1. Host Plant Resistance
 Description: This is the use of plant varieties that are naturally resistant or tolerant to
specific pests or diseases. These plants possess genetic traits that reduce the likelihood of
infestation or disease.

16.  Example: Developing and planting bajra (pearl millet) varieties that are resistant to
downy mildew or rust diseases.
2. Cultural Control
 Description: These are agricultural practices that reduce pest and disease incidence by
manipulating the environment, crop practices, or the timing of activities.
 Examples:
o Crop rotation: Changing the type of crop grown in a field each season to break the
life cycle of pests and diseases.
o Proper spacing: Planting crops at appropriate distances to reduce humidity levels
and the spread of fungal diseases.
o Sanitation: Removing plant debris that can harbor disease pathogens or pests.
3. Mechanical Control
 Description: This involves the physical removal or destruction of pests or infected plant
parts to reduce their numbers and impact.
 Examples:
o Handpicking: Manually removing pests like caterpillars or beetles from plants.
o Pruning: Cutting away diseased branches or leaves to prevent the spread of
pathogens.
o Tillage: Plowing the soil to disrupt the life cycle of soil-borne pests.
4. Physical Control
 Description: This method involves using physical barriers or environmental
modifications to prevent or reduce pest and disease problems.
 Examples:
o Mulching: Using organic or synthetic materials on the soil surface to prevent
weed growth and retain moisture.
o Row covers: Using fabrics to protect crops from insects and environmental
conditions like frost.

17. o Solarization: Using plastic sheets to cover the soil and trap solar energy, heating
the soil to kill pathogens and pests.
5. Legislative Control
 Description: This involves the use of laws and regulations to prevent the introduction
and spread of pests and diseases. It often includes quarantine measures, import
restrictions, and mandatory control practices.
 Examples:
o Quarantine: Restricting the movement of plants or plant products from areas
known to have certain diseases or pests.
o Phytosanitary certificates: Requiring documentation that plants or seeds are free
from pests and diseases before they can be transported across borders.
o Banning certain pesticides: Legislating the use of specific chemicals to protect
beneficial organisms and human health.
Lecture -6
Biological and chemical control
1. Biological Control
 Description: Biological control involves using living organisms, such as natural
predators, parasites, or pathogens, to suppress or control plant diseases. The goal is to
reduce the population of disease-causing organisms (pathogens) without the use of
chemical pesticides.
 Mechanisms of Action:
o Predation/Parasitism: Beneficial organisms, such as certain insects or
nematodes, directly attack and consume or parasitize pathogens.
o Competition: Beneficial microbes compete with pathogens for nutrients or space,
reducing the pathogens' ability to infect plants.

18. o Antibiosis: Some beneficial microbes produce substances that are toxic to
pathogens, inhibiting their growth or killing them.
o Induced Resistance: Certain beneficial organisms can trigger a plant's natural
defense mechanisms, making it more resistant to disease.
 Examples:
o Trichoderma spp.: Fungi used to control soil-borne pathogens like Fusarium and
Rhizoctonia by competing for nutrients and space.
o Bacillus subtilis: A bacterium used to control fungal diseases like powdery
mildew and downy mildew through antibiosis and competition.
o Mycorrhizal fungi: These fungi form symbiotic relationships with plant roots,
improving nutrient uptake and enhancing resistance to root pathogens.
o Entomopathogenic nematodes: These nematodes attack insect pests that act as
vectors for certain plant diseases.
2. Chemical Control
 Description: Chemical control involves the use of synthetic or natural chemical
substances, known as pesticides or fungicides, to kill or inhibit the growth of pathogens.
This method is often used when rapid control is necessary, or when other methods are not
effective.
 Types of Chemical Controls:
o Fungicides: Chemicals specifically designed to kill or inhibit the growth of fungi.
o Bactericides: Chemicals used to control bacterial diseases.
o Nematicides: Chemicals that target nematodes, which can cause plant diseases or
damage.
 Modes of Action:
o Contact: These chemicals kill pathogens on contact. They must be applied
directly to the affected area.
o Systemic: These chemicals are absorbed by the plant and move within its tissues,
providing protection from the inside. They can target pathogens within the plant.
o Protective: Applied before the pathogen infects the plant, these chemicals create
a protective barrier on the plant surface.

19. o Curative: Applied after infection has occurred, these chemicals can stop or
reduce the spread of the disease.
 Examples:
o Mancozeb: A contact fungicide used to control a wide range of fungal diseases
like blights, rusts, and leaf spots.
o Copper-based fungicides: These are broad-spectrum and used to control fungal
and bacterial diseases such as downy mildew, anthracnose, and bacterial leaf
spots.
o Carbendazim: A systemic fungicide effective against diseases like powdery
mildew, leaf spot, and rust.
o Streptomycin: An antibiotic used to control bacterial diseases like fire blight in
apple and pear trees.
Integrated Use of Biological and Chemical Controls
 In many cases, a combination of biological and chemical controls is used as part of an
Integrated Disease Management (IDM) approach. This strategy minimizes the reliance on
chemicals, reduces the risk of resistance development in pathogens, and helps maintain
environmental sustainability.

Lecture -7
Survey surveillance and fore casting of plant diseases
1. Survey of Plant Diseases
 Description: Surveys involve systematic data collection on the presence, prevalence, and
distribution of plant diseases within a specific area or crop. They help in identifying
disease hot spots, understanding disease dynamics, and guiding management strategies.
 Example:

20. o Wheat Rust Survey in India: In India, surveys are regularly conducted to
monitor wheat rust (Puccinia spp.), a serious fungal disease affecting wheat crops.
Field inspectors visit wheat-growing regions to assess rust incidence and severity.
They collect samples of infected plants, which are then analyzed in laboratories to
identify the rust races present. The data gathered helps in understanding the
spread and evolution of rust races, guiding the development of resistant wheat
varieties.
2. Surveillance of Plant Diseases
 Description: Surveillance involves ongoing, systematic monitoring of plant diseases to
detect new outbreaks, track disease progression, and assess the effectiveness of control
measures. It provides real-time data that can inform timely interventions.
 Example:
o Late Blight Surveillance in Potatoes: In regions where potatoes are a major
crop, such as Ireland, active surveillance systems are in place to monitor late
blight (Phytophthora infestans), a devastating disease. Surveillance networks,
including farmers, extension workers, and researchers, regularly monitor fields
and report any signs of the disease. Mobile apps and GIS tools are used to map
disease outbreaks, providing real-time alerts to farmers. This allows for quick
action, such as applying fungicides or removing infected plants, to prevent
widespread damage.
3. Forecasting of Plant Diseases
 Description: Disease forecasting involves predicting the likelihood, timing, and severity
of disease outbreaks based on historical data, current surveillance information, and
environmental factors such as weather conditions. Forecasts help in making proactive
decisions, such as when to apply fungicides or adopt other control measures.
 Example:
o Apple Scab Forecasting: Apple scab (Venturia inaequalis) is a common fungal
disease in apple orchards. Forecasting models have been developed to predict

21. scab outbreaks based on weather conditions, such as temperature and leaf
wetness. In the northeastern United States, these models are used to forecast scab
risk during the growing season. By analyzing weather data, the models predict
when conditions are favorable for scab infection, allowing growers to time
fungicide applications precisely to prevent the disease. This reduces the need for
unnecessary treatments, saving costs and minimizing environmental impact.
Integration of Survey, Surveillance, and Forecasting
 Collaborative Example:
o Rice Blast Disease Management in Asia: In many rice-growing regions of Asia,
such as the Philippines and Vietnam, integrated programs for managing rice blast
(Magnaporthe oryzae) are in place. Regular surveys are conducted to monitor the
presence and severity of the disease in different regions. Surveillance systems,
including local farmers, extension workers, and research institutions, provide
continuous data on disease occurrence. Forecasting models, which incorporate
weather data and disease history, predict the risk of outbreaks. These predictions
guide farmers on when to apply fungicides or adopt other control measures,
helping to reduce crop losses and improve yield.
Benefits of Integration:
 Early Detection: Surveys and surveillance enable the early identification of disease
outbreaks, which can be critical in preventing widespread damage.
 Timely Interventions: Forecasting provides actionable insights, allowing for timely and
targeted disease management practices.
 Resource Optimization: By combining data from surveys, surveillance, and forecasting,
farmers and agricultural managers can optimize the use of resources, such as fungicides,
labor, and time, while minimizing environmental impact.

22. Lecture -8
Safety issues in fungicide uses
1. Human Health Risks
 Description: Fungicides can pose risks to human health if not used properly. Exposure to
fungicides can occur through direct contact, inhalation, or ingestion, leading to acute or
chronic health effects.
 Issues:
o Acute Toxicity: Some fungicides can cause immediate health effects such as skin
irritation, respiratory problems, dizziness, or nausea if they are inhaled or come
into contact with skin.
o Chronic Health Effects: Prolonged or repeated exposure to certain fungicides
has been linked to long-term health issues, including cancer, reproductive harm,
and endocrine disruption.
 Example:
o Carbendazim: This fungicide, used to control a wide range of fungal diseases in
crops, has been associated with reproductive toxicity and potential carcinogenic
effects. Improper handling or excessive use can lead to harmful exposure for
farmworkers and consumers, especially if residue levels in food exceed safety
limits.
2. Environmental Impact
 Description: Fungicides can have significant effects on the environment, affecting non-
target organisms, contaminating water bodies, and disrupting ecosystems.
 Issues:
o Non-Target Toxicity: Fungicides can harm beneficial organisms, including
pollinators like bees, natural predators of pests, and soil microbes that contribute
to soil health.

23. o Water Contamination: Runoff from agricultural fields can carry fungicides into
rivers, lakes, and groundwater, affecting aquatic life and contaminating drinking
water sources.
o Persistence and Bioaccumulation: Some fungicides persist in the environment
for long periods and can accumulate in the tissues of plants, animals, and humans,
leading to ecological imbalances and health risks.
 Example:
o Chlorothalonil: A commonly used fungicide in various crops, Chlorothalonil has
been found to be highly toxic to aquatic organisms. Its runoff from agricultural
fields can lead to contamination of water bodies, negatively impacting fish and
other aquatic life.
3. Development of Resistance
 Description: Overuse or misuse of fungicides can lead to the development of resistance
in pathogens, making the fungicides less effective over time and requiring higher doses or
new chemicals to achieve control.
 Issues:
o Resistance Development: Pathogens exposed to sub-lethal doses of fungicides
can develop resistance, reducing the efficacy of the fungicide and making disease
management more challenging.
o Increased Use of Chemicals: As resistance develops, farmers may need to apply
fungicides more frequently or use higher doses, exacerbating the health and
environmental risks associated with fungicide use.
 Example:
o Powdery Mildew in Grapes: The repeated use of fungicides like DMI
(demethylation inhibitors) to control powdery mildew in grapevines has led to
resistance in some regions. This resistance forces growers to use alternative or
higher doses of fungicides, increasing costs and potential risks.
4. Residue Concerns in Food Products

24.  Description: Fungicide residues on crops can pose health risks to consumers if levels
exceed the maximum residue limits (MRLs) established by regulatory agencies.
 Issues:
o Food Safety: Consuming food with high levels of fungicide residues can lead to
health risks, particularly for vulnerable populations such as children, pregnant
women, and individuals with compromised immune systems.
o Trade Barriers: Countries have different MRLs, and crops exceeding these
limits can be rejected in international trade, leading to economic losses for
farmers and exporters.
 Example:
o Captan Residues in Apples: Captan is a fungicide commonly used in apple
orchards to control fungal diseases like scab. However, if not applied correctly, it
can leave residues on apples that exceed regulatory limits, posing risks to
consumers and leading to trade restrictions.
5. Regulatory and Compliance Issues
 Description: Fungicide use is regulated by national and international bodies to ensure
safety for humans and the environment. Non-compliance with these regulations can lead
to legal issues, fines, and loss of market access.
 Issues:
o Regulatory Compliance: Farmers and agricultural companies must adhere to
guidelines on fungicide application, including timing, dosage, and safety
precautions. Non-compliance can result in penalties and harm to public health and
the environment.
o Worker Protection: Regulations often require the use of personal protective
equipment (PPE) for farmworkers handling fungicides. Failure to comply can lead
to worker exposure and health risks.
 Example:
o Banned Fungicides: Some fungicides, such as certain formulations of Mancozeb,
have been banned or restricted in various countries due to their potential health

25. and environmental risks. Farmers using these chemicals in non-compliant ways
may face legal consequences and export restrictions.
Mitigation Strategies
 Use of Integrated Pest Management (IPM): Combining cultural, biological, and
mechanical controls with judicious use of fungicides to minimize reliance on chemicals.
 Proper Training and PPE: Ensuring that farmworkers are trained in safe fungicide
handling and application, and that they use appropriate protective equipment.
 Monitoring and Regulation: Regular monitoring of fungicide residues in food and the
environment, and strict enforcement of regulations to ensure safe use.
 Development of Resistant Varieties: Breeding and using plant varieties resistant to
diseases to reduce the need for fungicides.

Lecture -9
Political, social and legal implication of IDM
1. Political Implications
 Description: IDM practices are influenced by government policies, agricultural
programs, and international agreements. Political decisions can impact the adoption,
funding, and regulation of IDM strategies.
 Issues:
o Policy Support: Governments play a key role in promoting IDM through
agricultural policies, subsidies, and research funding. Lack of political will or
support can hinder the widespread adoption of IDM practices.
o Trade and Market Access: International trade agreements and phytosanitary
standards can affect the implementation of IDM. Countries with stricter disease
management practices may have better access to global markets.

26. o Resource Allocation: Political decisions on resource allocation for agricultural
research, extension services, and farmer education directly impact the success of
IDM programs.
 Example:
o European Union’s Sustainable Use of Pesticides Directive: The EU has
implemented regulations that promote reduced pesticide use and encourage
alternative disease management strategies, including IDM. This policy has
political implications for member states, as they must align their national practices
with EU directives. It also influences international trade, as non-EU countries
exporting to the EU must meet these standards, potentially requiring them to
adopt IDM practices.
2. Social Implications
 Description: IDM practices affect and are affected by social factors, including
community attitudes, farmer knowledge, and cultural practices. Social acceptance and
participation are crucial for the successful implementation of IDM.
 Issues:
o Farmer Participation: The success of IDM depends on farmers’ willingness to
adopt and implement diverse practices. Social factors such as education,
traditional knowledge, and community networks play a role in this adoption.
o Public Perception: The public’s perception of IDM, especially in relation to food
safety and environmental sustainability, can influence consumer demand and
policy support.
o Equity and Access: Social inequalities, such as access to resources, information,
and technology, can affect how different groups benefit from IDM practices.
Small-scale farmers may face challenges in adopting IDM due to limited
resources.
 Example:
o Farmer Field Schools (FFS) in Asia: In many Asian countries, Farmer Field
Schools have been established to educate farmers about IDM practices. These
schools promote community-based learning and empower farmers with

27. knowledge and skills to implement IDM. The social impact includes improved
livelihoods, better crop yields, and enhanced community cooperation. However,
the success of FFS depends on social factors such as community leadership,
gender dynamics, and local cultural practices.
3. Legal Implications
 Description: IDM practices are governed by legal frameworks that regulate pesticide
use, environmental protection, and agricultural practices. Legal issues arise from the need
to ensure compliance, protect intellectual property, and address liability concerns.
 Issues:
o Regulation of Pesticides: IDM promotes reduced reliance on chemical
pesticides, which are subject to stringent regulations. Legal frameworks govern
the registration, use, and disposal of pesticides, impacting how IDM is
implemented.
o Intellectual Property Rights (IPR): The development and use of disease-
resistant crop varieties, a key component of IDM, can be affected by IPR laws.
Patents on certain technologies or seeds can limit access for small-scale farmers.
o Liability and Compliance: Legal responsibilities for disease outbreaks, pesticide
residues, and environmental damage can raise liability concerns. Farmers and
companies must comply with laws related to environmental protection, worker
safety, and food safety.
 Example:
o Pesticide Regulation in the United States: The U.S. Environmental Protection
Agency (EPA) regulates the use of pesticides under the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA). IDM practices must comply with these
regulations, which include restrictions on certain chemicals and mandates for safe
use. Legal issues can arise if farmers or companies violate these regulations,
leading to fines, lawsuits, or loss of certification.
Integrated Example: The Case of Glyphosate

28.  Political: The use of glyphosate, a widely used herbicide, has become a politically
charged issue. Some countries have banned or restricted its use due to concerns about
health risks and environmental impact. This has led to debates over the role of chemical
controls in IDM and the need for alternative strategies.
 Social: Public concern over the potential health risks of glyphosate has influenced
consumer behavior, with some opting for organic products. This shift has pressured
farmers and companies to adopt IDM practices that reduce or eliminate the use of
glyphosate.
 Legal: Numerous lawsuits have been filed against companies producing glyphosate,
alleging that it causes cancer. These legal challenges have prompted stricter regulations
and encouraged the adoption of IDM practices that rely less on chemical controls.
Impact of Political, Social, and Legal Factors on IDM
 Adoption Rates: The success of IDM is closely tied to the political, social, and legal
environment. Supportive policies, social acceptance, and clear legal frameworks
encourage adoption, while barriers in these areas can hinder it.
 Sustainability: By addressing the political, social, and legal implications, IDM can
contribute to more sustainable agricultural practices, balancing the needs of food
production, environmental protection, and social equity.