Unit 1 - IDM | Principles of Integrated Disease Management

Syllabus 

IDM: Introduction, history, importance, concepts, principles and tools of IDM.

IDM

Introduction to Integrated Disease Management (IDM):

Integrated Disease Management (IDM) is a holistic and sustainable approach used in agriculture to control plant diseases effectively while minimizing adverse environmental impacts and ensuring long-term productivity. It is a science-based strategy that integrates various disease management tactics to achieve the best possible outcome. IDM aims to strike a balance between economic feasibility, environmental conservation, and social well-being. IDM emphasizes prevention, early detection, and the use of a variety of tools to maintain healthy plant populations and achieve optimal yields. This approach is particularly crucial in modern agriculture, where minimizing chemical inputs and promoting sustainable practices are paramount.

“Disease management system that in the context of associated environment and population dynamics of microorganisms, utilizes all suitable techniques and methods in a manner as compatible as possible and maintains the disease below economic level”.

History of Integrated Disease Management:

The history of Integrated Disease Management (IDM) can be traced back to the evolution of agricultural practices and the understanding of plant diseases. While the concept of integrating various approaches for disease management has ancient origins, the formalization and development of IDM as a systematic approach began to take shape in the 20th century. Early Agricultural Practices: Throughout history, farmers have employed various practices to manage plant diseases, often unknowingly practicing elements of what we now consider IDM. Crop rotation, intercropping, and selecting disease-resistant plants were common practices used to reduce disease impact.

Emergence of Modern Plant Pathology: The late 19th and early 20th centuries marked the development of modern plant pathology as a scientific discipline. Researchers began to study the causes, mechanisms, and control of plant diseases systematically.

Shift from Chemical Control to Integrated Approaches: In the mid-20th century, the widespread use of synthetic pesticides for disease control gained momentum. However, the drawbacks of solely relying on chemical control, such as pesticide resistance and environmental concerns, became evident.

1960s-1970s: Early Formulation of IDM: • During this period, researchers and practitioners started recognizing the limitations of chemical control and the need for a more holistic approach. • The term "Integrated Pest Management" (IPM) emerged as a concept that aimed to combine multiple strategies, including biological, cultural, and chemical, for pest and disease management. It originated from the concept of "integrated control" proposed by entomologists from the University of California.

1980s-1990s: Expansion of IDM: • Integrated Disease Management began to be recognized as a distinct subset of IPM, focusing specifically on managing plant diseases. • Researchers and agricultural extension services began to promote the integration of various approaches, such as resistant cultivars, cultural practices, and biological control, to manage plant diseases effectively.

21st Century: Advancements and Emphasis on Sustainability: • The 21st century witnessed increased attention to sustainable agriculture and the role of IDM in achieving it. • Global concerns about the environment, food safety, and the impact of chemicals led to a renewed emphasis on integrated approaches for disease management.

Current State and Future Directions: • Today, IDM has become a standard approach in modern agriculture, emphasizing the importance of combining various strategies to manage plant diseases effectively while minimizing negative impacts on the environment and human health. • Ongoing research and technological advancements continue to contribute to the development of new tools and techniques for integrated disease management.

In summary, Integrated Disease Management has evolved over time from traditional agricultural practices to a scientifically based and holistic approach that recognizes the complexity of plant-disease interactions. It emphasizes combining multiple strategies for disease management, with the ultimate goal of achieving sustainable and environmentally friendly agriculture.

Importance of Integrated Disease Management:

1. Sustainable Agriculture: IDM promotes sustainable agricultural practices by reducing reliance on chemical pesticides and encouraging the use of environmentally friendly disease management strategies. This helps preserve natural resources, biodiversity, and the overall health of agroecosystems.
2. Resilience to Disease Outbreaks: By combining multiple disease management tactics, IDM creates a resilient and robust agricultural system that can withstand disease outbreaks more effectively. Crop diversity and cultural practices help mitigate the impact of specific diseases on entire crops.
3. Reduced Chemical Use: By integrating cultural practices, biological controls, and resistant plant varieties, IDM can significantly reduce the need for chemical pesticides. This minimizes chemical residues in crops, soil, water, and the environment, benefiting both human health and ecosystems.
4. Economic Viability: IDM aims to optimize disease management strategies, reducing the overall cost of controlling diseases while maintaining or improving crop yields and quality. This enhances the economic viability of farming operations.
5. Reduced Environmental Impact: By minimizing the use of chemical pesticides, IDM contributes to reducing environmental pollution and the harmful effects on beneficial organisms, such as pollinators and natural enemies of pests.
6. Public Health and Safety: IDM emphasizes the safe and judicious use of pesticides, thereby reducing potential risks to farm workers, consumers, and the environment.
7. Innovation and Research: The implementation of IDM encourages research and innovation in disease management, leading to the development of new technologies, biological control agents, and resistant crop varieties.
8. Adaptation to Climate Change: IDM promotes a diversified and adaptable agricultural system, which is essential in coping with the challenges posed by climate change and emerging diseases.
9. Preserving Beneficial Organisms: Biological control methods used in IDM preserve natural enemies of pests and diseases, maintaining a balanced ecosystem. This can lead to a reduction in secondary pest outbreaks and a more resilient agroecosystem.
10. Integrated Approach: IDM recognizes the complexity of disease interactions and addresses them with a holistic strategy. Rather than relying on a single control method, IDM combines various tools to tailor disease management strategies to specific crops, regions, and situations.

Concepts of Integrated Disease Management (IDM):

Integrated Disease Management (IDM) is a comprehensive and sustainable approach used in agriculture to effectively control plant diseases while minimizing negative impacts on the environment and ensuring long-term productivity. It involves combining multiple disease management tactics to achieve the best possible outcome. The key concepts of IDM are:

1. Holistic Approach: IDM takes a holistic approach that considers the entire agroecosystem, including crops, soil, climate, pests, beneficial organisms, and cultural practices. It addresses the underlying causes of diseases rather than focusing solely on symptoms.
2. Disease Management Tactics: IDM integrates various disease management tactics, such as cultural practices, resistant crop varieties, biological control, chemical control (if necessary), and monitoring systems, to create a synergistic effect in controlling diseases.
3. Sustainable Practices: IDM emphasizes sustainable agricultural practices that minimize reliance on chemical pesticides and promote environmentally friendly disease management strategies.
4. Crop Diversification: Crop diversification is a fundamental aspect of IDM, as it helps reduce the risk of large-scale disease outbreaks and enhances the resilience of the agricultural system.
5. Economic Viability: IDM aims to optimize disease management strategies to reduce costs while maintaining or improving crop yields and profitability for farmers.
6. Adaptability: IDM encourages adaptability in disease management approaches, as different crops, regions, and environmental conditions may require tailored solutions.
7. Prevention and Early Detection: IDM emphasizes preventing disease outbreaks through measures like crop rotation, sanitation, and planting disease-resistant varieties. Early detection of diseases through regular monitoring allows for timely intervention.
8. Diverse Strategies: IDM integrates various strategies, including cultural practices, biological controls, resistant plant varieties, chemical interventions, and monitoring techniques, to effectively manage and control diseases.
9. Site-Specific Management: IDM considers local conditions such as climate, soil, and cropping systems. Disease management plans are tailored to the specific needs of each location.
10. Stakeholder Collaboration: IDM often involves collaboration among researchers, extension services, farmers, and other stakeholders.

Principles of Integrated Disease Management:

1. Prevention First: The primary principle of IDM is prevention. Emphasize preventive measures such as using disease-resistant crop varieties, precising crop rotation, and maintaining proper sanitation to reduce disease incidence.
2. Diversity and Resilience: Encourage crop diversification to reduce the risk of disease outbreaks and enhance the resilience of the agroecosystem.
3. Threshold-Based Control: Use monitoring systems to set economic injury thresholds, where intervention is triggered only when disease levels exceed a certain economic threshold.
4. Integration of Tactics: Integrate multiple disease management tactics, such as cultural practices, biological control, and chemical control, to create a synergistic effect and maximize disease control.
5. Environmentally Friendly Practices: Preferentially use environmentally friendly and less-toxic disease management strategies to minimize harm to non-target organisms and the environment.
6. Regular Monitoring: Regularly monitor crops for disease incidence and severity to identify potential problems early and make timely management decisions.

Principles of Plant Disease Control 
1. Avoidance—prevents disease by selecting a time of the year or a site where there is no inoculum or where the environment is not favorable for infection. 
2. Exclusion—prevents the introduction of inoculum. 
3. Eradication—eliminates, destroy, or inactivate the inoculum. 
4. Protection—prevents infection by means of a toxicant or some other barrier to infection. 
5. Resistance—utilizes cultivars that are resistant to or tolerant of infection. 
6. Therapy—cure plants that are already infected

Tools of Integrated Disease Management:

Integrated Disease Management (IDM) employs a variety of tools and techniques to effectively manage and control plant diseases while promoting sustainable agriculture. These tools encompass different strategies and methods to address disease-related challenges. Here are some key tools used in IDM:

1. Resistant Host Plant Varieties: • Using plant varieties that are naturally resistant to specific diseases is a fundamental tool in IDM. Breeding for resistance involves selecting and developing cultivars with genetic traits that provide protection against pathogens. • Resistant varieties can be the simple, practical, effective and economical method of plant disease control. • Apart from ensuring protection from diseases, they can also save time, money and energy spent on other methods of control and avoid environmental pollution with chemicals. • They are the only practical method of controlling such diseases as wilts, rusts and others caused by viruses in which chemical control is very expensive and impractical. • In low value crops, where other methods are often too expensive, development of varieties resistant to common and important diseases can be an acceptable recommendation for the farmers. • Disease resistance in plants is also governed by their genetic constitution and can be monogenic, oligogenic or polygenic. Source 2. Cultural Practices: Cultural practices are essential tools for disease prevention. These practices include crop rotation, proper spacing, optimizing planting density, adjusting irrigation practices, and implementing good sanitation practices.

Deep ploughing • Deep ploughing of the field results in exposure of propagules to elevated temperatures and physical killing of the pathogen. This can be regarded as dry soil solarization. • Summer ploughing was effective at reducing populations of cyst nematodes and increasing wheat yield.

Flooding of the field Flooding of the field somewhat resembles soil disinfestation Long-term summer soil flooding, with or without paddy culture found to be decreased populations of soil borne pathogens.

Crop Rotation and Diversification: Alternating the types of crops grown in a field can disrupt the life cycle of pathogens, reducing disease pressure. Diversification promotes a balanced ecosystem and reduces the buildup of specific pathogens.

Residue Management: Practices such as removing and disposing of infected plant debris, plowing under crop residues, and practicing crop rotation can help reduce the survival and spread of pathogens.

Other good culture practices
• In order to reduce dispersal of soil borne pathogens between fields, stakes and farm equipment should be decontaminated before moving from one field to the next.
• Avoid soil movement from one site to another to reduce the risk of moving pathogens.
• Weed control is important for the management of viral diseases.
• Some pathogens can only enter the host through wounds, situations that promote plant injury should be avoided.
• The pathogen inoculum can be reduced by removing plant material (infected and healthy) after harvest.

3. Biological Control Agents: Beneficial organisms like predators, parasitoids, and beneficial microbes are used to control disease-causing organisms. These natural enemies help keep disease populations in check, promoting a balanced ecosystem.
• Biocontrol agents are used as a core component of integrated disease management system. (Example: Bacillus subtilis, Pseudomonas fluorescens, Gliocladium spp., and more)

Biopesticides: Biopesticides are derived from natural sources such as fungi, bacteria, and plant extracts. They provide an alternative to synthetic chemical pesticides and can be effective in controlling diseases.

Predators and Parasites: Just as predators keep insect populations in check, some insects and mites feed on plant pathogens. For instance, predatory nematodes attack harmful nematodes in the soil, while parasitic wasps lay eggs inside pest insects.

Competition: By introducing non-pathogenic strains of a disease-causing microorganism, you can create competition for resources, making it harder for the harmful strain to establish.

Induced Resistance: Beneficial microorganisms can stimulate the plant's natural defense mechanisms, making them more resistant to diseases.

4. Physical Control: This involves using physical barriers or methods to prevent the spread of diseases. Examples include using row covers, mulching, and sanitation practices to limit disease transmission

Collect and destroy the disease infected plant parts.

Soil solarization • It has been used to control soil borne diseases caused by otherwise difficult to control fungi, e.g., Rhizoctonia solani, Fusarium spp., Sclerotium etc .
• In this the soil beds are first irrigated and then covered with thin (20 µm) transparent mulch in the months of April, May and June.
• It raised the soil temperatures in some cases up to 50°C, which is deleterious to many plant pathogens in the soil. • It has been used in raising disease free nursery in tropical and subtropical climatic areas. It also provides excellent weed control.

Hot water treatment
• Some seed borne diseases can be treated by hot water treatment by immersing infected seeds in hot water at recommended temperature and time.
• Hot water treatment of cabbage seed at 52°C for 15-20 minutes controls black rot disease (caused by Xanthomonas campestris pv. campestris).

Hot air treatment
It is given to remove excess of moisture from plant organs and protect them from fungal and bacterial attack. Several virus infected dormant plants are treated by hot air treatment at a temperature ranging from 35-54°C for 8 h.

Refrigeration (low temperature treatment) is most common method used to prevent postharvest diseases of perishables fruits and vegetables.

Solar heat treatment
• Solar heat treatment of the water soaked wheat seed in May-June for 5-6 hours provides good control of loose smut of wheat.
• Most of the post harvest diseases can be avoided by irradiation, refrigeration, Controlled Atmosphere Storage etc.

5. Chemical Control (As a Last Resort): In situations where other methods are insufficient, carefully selected chemical pesticides can be used. The key is to apply chemicals judiciously, considering factors like target specificity, application timing, and potential impact on non-target organisms.

Types of Chemicals: Chemical control involves the application of various types of chemicals:
• Fungicides: Used to target fungal diseases.
• Bactericides: Target bacterial diseases.
• Insecticides: Target insect pests.
• Nematicides: Target nematode pests.
• Virucides: Target viral diseases (limited options available).

Seed Treatment: Applying fungicides, biological agents, or other treatments to seeds before planting can provide early protection against soilborne diseases.

Disease Thresholds: Disease thresholds determine the point at which intervention is necessary to prevent economic damage. These thresholds help farmers make informed decisions about disease management measures.

6. Quarantine & regulatory measures:
• Preventing the introduction and spread of exotic pathogens through quarantine measures and strict regulations is an important aspect of IDM.
• Plant quarantine is the legally forced restriction on the movement of diseased plant materials or of fungi, bacteria or viruses that cause disease in plants.
• Quarantine & regulatory measures is a tool of Exclusion, one of the Principles of Plant Disease Control

By employing a combination of these tools, IDM aims to create a comprehensive, effective, and sustainable approach to managing and controlling plant diseases while minimizing negative impacts on the environment and human health.

Conclusion:

Integrated Disease Management (IDM) is a comprehensive and sustainable approach that aims to effectively manage plant diseases while preserving the environment and ensuring economic viability. Its historical development and evolution from traditional pest control methods to a more holistic approach underscore its importance in modern agriculture. It combines various disease management tactics to effectively control plant diseases while minimising environmental impact. 

By integrating various disease management strategies, IDM contributes to sustainable agriculture, reduced environmental impact, enhanced resilience to disease outbreaks, and improved overall agricultural productivity and food security.

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