This document summarizes a seminar presentation on the interaction between the environment and plant pathogens in plant diseases. It discusses how climate change impacts the three elements of the disease triangle: the host, pathogen, and environment. It describes how increased carbon dioxide and temperatures can influence pathogen growth and disease development. Specifically, it provides examples of how higher temperatures and carbon dioxide levels can increase the severity of certain diseases in crops like wheat, citrus, and soybean, while decreasing other diseases. The document also reviews historical developments in the field of plant disease epidemiology.
The document discusses the gene-for-gene hypothesis and concepts of vertical and horizontal resistance. It provides background on the gene-for-gene hypothesis proposed by Flor, which states that for each resistance gene in the host there is a corresponding avirulence gene in the pathogen. Vertical resistance is conferred by single major genes and is race-specific, while horizontal resistance is polygenic and provides more durable, race-non-specific resistance against a pathogen. The document explores the biochemical basis and implications of the gene-for-gene hypothesis.
In this slide you will get all the important information of epidemiology.
For more information you can see my youtube channel
https://www.youtube.com/channel/UCUsmJMc2xvL3O3UkDh8knrA
This document discusses disease forecasting models that use weather data to predict outbreaks. It provides examples of models for rice blast, potato late blight, wheat yellow rust, and more. The potato late blight model for India, JHULSACAST, is specifically discussed. Disease forecasting is useful for giving advance warning to apply protective chemicals before infection starts and help control economically important crop diseases. Both empirical and fundamental forecasting systems are covered, along with their components and requirements for developing useful forecasting.
This document provides an introduction to the course PPATH 503: Epidemiology and Forecasting of plant disease. It defines key epidemiological concepts such as epidemic, epidemiology, monocyclic and polycyclic pathogens. It discusses how host, pathogen and environmental factors influence disease development. It also examines the history of epidemiology from ancient times to modern developments. Disease progress curves and mathematical modeling of epidemics are introduced.
The document discusses several topics related to climate change and plant breeding:
1. It outlines natural and human causes of climate change such as changes in the sun's energy output and increasing greenhouse gas emissions.
2. It describes how plants may respond to climate change through extinction, range shifts, habitat fragmentation, genetic differentiation, migration, and phenotypic plasticity.
3. It discusses strategies for improving crop resilience through crop diversification, ideotype breeding, and mutation breeding. Crop diversification involves mixing varieties to reduce pest and disease impacts. Ideotype breeding develops optimized crop models. Mutation breeding enhances genetic variability.
Breeding for resistance to disease and insect pests(biotic stress)Pawan Nagar
Breeding for resistance to plant diseases and insect pests (biotic stress) involves targeting six main groups of pests: airborne fungi, soil-borne fungi, bacteria, viruses, nematodes, and insects. Plant breeders develop strategies to breed cultivars resistant to these types of biotic stress through an understanding of the biology and damage caused. Breeding can involve improving vertical/qualitative resistance to specific pathogen races or strains, as well as horizontal/partial resistance effective against all pathogen variants. Strategies include using differential varieties to identify pathogen races, planned release of resistance genes, gene pyramiding, combining vertical and horizontal resistance, and utilizing wild plant germplasm.
The broadest definition of plant disease includes anything that damages plant health. This definition can include such diverse factors as pathogens, insufficient nitrogen, air pollution, lawnmower damage, and deer damage.
The concept of gene for gene hypothesis was first developed by Flor in 1956 based on his studies of host pathogen interaction in flax, for rust caused by Melampsora lini. The gene for gene hypothesis states that for each gene controlling resistance in the host, there is corresponding gene controlling pathogenicity in the pathogen. The resistance of host is governed by dominant genes and virulence of pathogen by recessive genes. The genotype of host and pathogen determine the disease reaction. When genes in host and pathogen match for all loci, then only the host will show susceptible reaction. If some gene loci remain unmatched, the host will show resistant reaction. Now gene – for –gene relationship has been reported in several other crops like potato, sorghum, wheat, etc. The gene for gene hypothesis is also known as “Flor Hypothesis.”
The document discusses the gene-for-gene hypothesis and concepts of vertical and horizontal resistance. It provides background on the gene-for-gene hypothesis proposed by Flor, which states that for each resistance gene in the host there is a corresponding avirulence gene in the pathogen. Vertical resistance is conferred by single major genes and is race-specific, while horizontal resistance is polygenic and provides more durable, race-non-specific resistance against a pathogen. The document explores the biochemical basis and implications of the gene-for-gene hypothesis.
In this slide you will get all the important information of epidemiology.
For more information you can see my youtube channel
https://www.youtube.com/channel/UCUsmJMc2xvL3O3UkDh8knrA
This document discusses disease forecasting models that use weather data to predict outbreaks. It provides examples of models for rice blast, potato late blight, wheat yellow rust, and more. The potato late blight model for India, JHULSACAST, is specifically discussed. Disease forecasting is useful for giving advance warning to apply protective chemicals before infection starts and help control economically important crop diseases. Both empirical and fundamental forecasting systems are covered, along with their components and requirements for developing useful forecasting.
This document provides an introduction to the course PPATH 503: Epidemiology and Forecasting of plant disease. It defines key epidemiological concepts such as epidemic, epidemiology, monocyclic and polycyclic pathogens. It discusses how host, pathogen and environmental factors influence disease development. It also examines the history of epidemiology from ancient times to modern developments. Disease progress curves and mathematical modeling of epidemics are introduced.
The document discusses several topics related to climate change and plant breeding:
1. It outlines natural and human causes of climate change such as changes in the sun's energy output and increasing greenhouse gas emissions.
2. It describes how plants may respond to climate change through extinction, range shifts, habitat fragmentation, genetic differentiation, migration, and phenotypic plasticity.
3. It discusses strategies for improving crop resilience through crop diversification, ideotype breeding, and mutation breeding. Crop diversification involves mixing varieties to reduce pest and disease impacts. Ideotype breeding develops optimized crop models. Mutation breeding enhances genetic variability.
Breeding for resistance to disease and insect pests(biotic stress)Pawan Nagar
Breeding for resistance to plant diseases and insect pests (biotic stress) involves targeting six main groups of pests: airborne fungi, soil-borne fungi, bacteria, viruses, nematodes, and insects. Plant breeders develop strategies to breed cultivars resistant to these types of biotic stress through an understanding of the biology and damage caused. Breeding can involve improving vertical/qualitative resistance to specific pathogen races or strains, as well as horizontal/partial resistance effective against all pathogen variants. Strategies include using differential varieties to identify pathogen races, planned release of resistance genes, gene pyramiding, combining vertical and horizontal resistance, and utilizing wild plant germplasm.
The broadest definition of plant disease includes anything that damages plant health. This definition can include such diverse factors as pathogens, insufficient nitrogen, air pollution, lawnmower damage, and deer damage.
The concept of gene for gene hypothesis was first developed by Flor in 1956 based on his studies of host pathogen interaction in flax, for rust caused by Melampsora lini. The gene for gene hypothesis states that for each gene controlling resistance in the host, there is corresponding gene controlling pathogenicity in the pathogen. The resistance of host is governed by dominant genes and virulence of pathogen by recessive genes. The genotype of host and pathogen determine the disease reaction. When genes in host and pathogen match for all loci, then only the host will show susceptible reaction. If some gene loci remain unmatched, the host will show resistant reaction. Now gene – for –gene relationship has been reported in several other crops like potato, sorghum, wheat, etc. The gene for gene hypothesis is also known as “Flor Hypothesis.”
The document discusses plant disease resistance genes (R-genes) and their importance in crop breeding for disease resistance. It contains the following key points:
1. R-genes encode receptors that recognize pathogen effector proteins and trigger plant immune responses. Most R-genes contain nucleotide binding and leucine-rich repeat domains.
2. Dozens of R-genes have been cloned from various plants using map-based cloning, transposon tagging, or a new method called MutRenSeq that enriches for R-gene sequences.
3. Introducing R-genes from wild crop relatives into domestic crops can provide natural and sustainable resistance to diseases while avoiding pesticide use and potential environmental damage.
impact of climate change on disease developement and managementprakash mani kumar
climate play an important role in the disease developement in plant. the effects of changes in temperature, CO2 and ozone concentrations, precipitation, and drought on the biology of pathogens and their ability to infect plants and survive in natural and agricultural environments. The climate influences the incidence as well as temporal and spatial distribution of plant diseases. Climate affects all life stages of the pathogen and host and clearly poses a challenge to many pathosystems.
This document summarizes key events and discoveries in the development of virology from the 16th century to present day. Some of the highlights include:
- In 1892, Dmitri Ivanovsky discovered that the causal agent of tobacco mosaic disease could pass through bacteria-proof filters, showing that it was smaller than bacteria.
- In 1898, Martinus Beijerinck coined the term "virus" and described the liquid containing the infectious agent as "contagium vivum fluidum", establishing viruses as a new category of disease-causing agents.
- In the 1930s and 1940s, scientists including Wendell Stanley, F. Bawden and N. Pirie began pur
Plant pathology is the study of diseases that affect plants. It examines the microorganisms and environmental factors that cause plant diseases, as well as methods for preventing and controlling diseases. Plant pathogens include viruses, bacteria, fungi, nematodes, and other microbes that infect plants and cause damage. A key goal of plant pathology is minimizing crop losses from diseases, which globally account for 36.5% of annual losses. Understanding plant diseases and their causes is crucial for improving global food security.
breeding for biotic, abiotic stress ,yield, stability and adaptation traitsNugurusaichandan
This document discusses breeding for biotic stress resistance, specifically disease resistance in crops. It defines key terms related to diseases, pathogens, and disease resistance mechanisms in plants. It describes different types of disease resistance including disease escape, tolerance, genetic resistance, and immunity. It explains the genetic basis of disease resistance, including oligogenic, polygenic, and cytoplasmic inheritance. Sources of disease resistance and methods for breeding for disease resistance like introduction, selection, hybridization, and mutation breeding are also summarized.
This document summarizes the movement and physiology of virus-infected plants. It discusses three types of virus movement: intracellular, intercellular, and long-distance. Intracellular movement relies on the endoplasmic reticulum and cytoskeleton, while intercellular movement occurs through plasmodesmata connecting adjacent cells. Long-distance movement involves viruses entering the vascular system and moving systemically through the plant. It also examines effects on the infected plant's photosynthesis, respiration, membrane permeability, translocation, and transcription/translation, such as reduced chlorophyll and sucrose content as well as increased respiration and permeability.
Variability arises in plant pathogens through various genetic mechanisms such as mutation, hybridization, and recombination. This variability allows pathogens to evolve new races or strains that can infect resistant host varieties and overcome plant resistance. The document discusses several mechanisms that generate variability in fungi, bacteria, and viruses, including mutation, transformation, transduction, conjugation, heterokaryosis, parasexualism, and recombination, which allow pathogens to adapt to new environments and hosts. Understanding pathogen variability is important for breeding disease-resistant crop varieties.
Impact of climate change on plant diseases.pptxPRAVINABARDE
Climate change is affecting plant diseases in several ways. Rising temperatures and changing precipitation patterns are altering the spread and severity of existing diseases while also introducing new disease threats. Pathogen virulence and survival rates are increasing under warmer conditions, while host resistance and disease management practices are becoming less effective. Successful disease management will require strategies adapted to the new climatic conditions, including developing resistant crop varieties and validating forecasting models under a changing climate.
i) Breeding crops for resistance to insects, diseases, and abiotic stresses like drought is important to reduce yield losses and costs of control measures.
ii) Mechanisms of resistance include non-preference, antibiosis, tolerance, avoidance, and physiological or biochemical traits like hairiness, toxins, or proline accumulation.
iii) Sources of resistance come from cultivated varieties, germplasm collections, and related wild species, and screening is done under field or controlled conditions.
Gene for-gene hypothesis & its validty in the present scenarioDr. Nimit Kumar
This document summarizes a seminar on disease development and resistance. It discusses the disease triangle, types of resistance, components of disease resistance including R and Avr genes, and Flor's gene-for-gene hypothesis. Molecular models of direct and indirect R-Avr gene interaction are presented. Examples of characterized R genes in crops like maize, rice, and tobacco are provided. Past work on disease resistance in flax at the university is summarized, as is current molecular characterization work in the department.
Drought stress and tolerance mechanisms in cropsMohaned Mohammed
Drought stress accounts for more crop production losses than any other factor. The presentation discusses the causes and effects of drought stress on plants and various tolerance mechanisms. It outlines that drought avoidance mechanisms include increased water absorption and transport, deep root systems, and reduced transpiration. Physiological responses include osmolyte accumulation, antioxidant production, and hormonal changes. Developing crops with drought tolerant traits through both conventional and molecular breeding approaches will be important for improving productivity under increasing drought conditions from climate change.
1) The gene for gene hypothesis states that for each resistance gene in the host plant, there is a corresponding avirulence gene in the pathogen. When the two match, the plant is resistant and disease does not occur.
2) When a new resistant variety is developed and widely grown, it creates a "boom and bust cycle" - as the variety booms in popularity, it puts selection pressure on the pathogen population that favors strains that can overcome its resistance, leading to an epidemic that causes the variety's popularity to bust.
3) The "Vertifolia effect" occurs when a variety's resistance is overcome by new pathogen strains, as happened with the potato variety Vertifolia - its resistance
1. What is pathogen variability?
2. Significance of pathogen Variability
3. Stages of variation
4. Mechanism of Variability in fungi
5. Characterization of variability among plant pathogens
The document discusses the development of Phytophthora and Pythium databases to support the identification and monitoring of these major plant pathogen groups. It describes the objectives of building a cyberinfrastructure to archive genotype, phenotype and distribution data on Phytophthora species/isolates. The Phytophthora Database provides tools for sequence analysis, phylogenetic analysis and molecular identification. Future directions include expanding to other plant pathogen databases and integrating genomic and geospatial data.
Effects of climate change on plant disease scenarioShamsher Alam
The document discusses the effects of climate change on plant diseases. It describes how increased greenhouse gas emissions and global warming are altering weather patterns and affecting plant-pathogen interactions. Specifically, it notes that higher carbon dioxide levels and temperatures are increasing canopy sizes and disease susceptibility. Changes in moisture levels and precipitation patterns are also influencing the spread and prevalence of various fungal and bacterial diseases. The document concludes by calling for more sustainable agricultural practices and novel disease management strategies that can help address plant health challenges under continuing climate change.
This presentation gives the insight idea about drought and its effect on the plant system also talks about development of drought-tolerant variety for ensuring food security.
plant drought effects, mechanisms and managementG Mahesh
This presentation provides an overview of plant drought stress, including its effects, mechanisms, and management strategies. Drought stress can impact plant growth, yield, water relations, photosynthesis, nutrient uptake, and cause oxidative damage. Plants have developed morphological, physiological and molecular mechanisms to tolerate drought, such as escaping dry conditions, reducing water loss through stomatal control, antioxidant production, and accumulating compatible solutes. The presentation also discusses strategies to manage drought, including improving crop genotypes and optimizing agronomic practices to enhance drought resistance.
Importance of epidemics in mono and poly cyclic diseases caused by various plant pathogens and the mathematical models for studying the strategy of those epidemics
Introduction importance scope and objectives of plant pathologyAnurAg Kerketta
This document provides an introduction to the field of plant pathology by defining it as the study of plant diseases, their causes, and management. It discusses how plant pathology relates to other sciences and its key objectives, which include studying the etiology, pathogenesis, epidemiology, and control of plant diseases. The document emphasizes the importance of plant pathology, noting that diseases cause billions in annual crop losses worldwide. It provides examples of historical famines and epidemics caused by plant diseases. Finally, it outlines the broad scope of plant pathology in surveying, identifying, assessing, and developing management strategies for economically important plant diseases.
Effect of climate change on crop pest interactions, area shift, food producti...Sunil Kumar
This document summarizes the effects of climate change on the interactions between crop pests and diseases. It discusses how higher temperatures and altered precipitation patterns may favor the proliferation of insect pests and change the spread of plant diseases. Climate change can influence host-pathogen interactions and affect disease management. It may also lead to range shifts of pests and the northward expansion of some diseases. Increased focus is needed on how climate change will affect the evolution of hosts and pathogens over time.
Climate change is altering plant disease development through its effects on the disease triangle of pathogens, hosts, and the environment. Rising CO2 levels can both increase pathogen growth and modify plant defenses. Higher temperatures can influence pathogen virulence and host resistance. Changes in precipitation patterns impact moisture levels and thus disease occurrence. Climate change is modifying the effectiveness of disease management approaches like fungicides. More research is still needed to fully understand and address the impacts of climate change on plant health.
The document discusses plant disease resistance genes (R-genes) and their importance in crop breeding for disease resistance. It contains the following key points:
1. R-genes encode receptors that recognize pathogen effector proteins and trigger plant immune responses. Most R-genes contain nucleotide binding and leucine-rich repeat domains.
2. Dozens of R-genes have been cloned from various plants using map-based cloning, transposon tagging, or a new method called MutRenSeq that enriches for R-gene sequences.
3. Introducing R-genes from wild crop relatives into domestic crops can provide natural and sustainable resistance to diseases while avoiding pesticide use and potential environmental damage.
impact of climate change on disease developement and managementprakash mani kumar
climate play an important role in the disease developement in plant. the effects of changes in temperature, CO2 and ozone concentrations, precipitation, and drought on the biology of pathogens and their ability to infect plants and survive in natural and agricultural environments. The climate influences the incidence as well as temporal and spatial distribution of plant diseases. Climate affects all life stages of the pathogen and host and clearly poses a challenge to many pathosystems.
This document summarizes key events and discoveries in the development of virology from the 16th century to present day. Some of the highlights include:
- In 1892, Dmitri Ivanovsky discovered that the causal agent of tobacco mosaic disease could pass through bacteria-proof filters, showing that it was smaller than bacteria.
- In 1898, Martinus Beijerinck coined the term "virus" and described the liquid containing the infectious agent as "contagium vivum fluidum", establishing viruses as a new category of disease-causing agents.
- In the 1930s and 1940s, scientists including Wendell Stanley, F. Bawden and N. Pirie began pur
Plant pathology is the study of diseases that affect plants. It examines the microorganisms and environmental factors that cause plant diseases, as well as methods for preventing and controlling diseases. Plant pathogens include viruses, bacteria, fungi, nematodes, and other microbes that infect plants and cause damage. A key goal of plant pathology is minimizing crop losses from diseases, which globally account for 36.5% of annual losses. Understanding plant diseases and their causes is crucial for improving global food security.
breeding for biotic, abiotic stress ,yield, stability and adaptation traitsNugurusaichandan
This document discusses breeding for biotic stress resistance, specifically disease resistance in crops. It defines key terms related to diseases, pathogens, and disease resistance mechanisms in plants. It describes different types of disease resistance including disease escape, tolerance, genetic resistance, and immunity. It explains the genetic basis of disease resistance, including oligogenic, polygenic, and cytoplasmic inheritance. Sources of disease resistance and methods for breeding for disease resistance like introduction, selection, hybridization, and mutation breeding are also summarized.
This document summarizes the movement and physiology of virus-infected plants. It discusses three types of virus movement: intracellular, intercellular, and long-distance. Intracellular movement relies on the endoplasmic reticulum and cytoskeleton, while intercellular movement occurs through plasmodesmata connecting adjacent cells. Long-distance movement involves viruses entering the vascular system and moving systemically through the plant. It also examines effects on the infected plant's photosynthesis, respiration, membrane permeability, translocation, and transcription/translation, such as reduced chlorophyll and sucrose content as well as increased respiration and permeability.
Variability arises in plant pathogens through various genetic mechanisms such as mutation, hybridization, and recombination. This variability allows pathogens to evolve new races or strains that can infect resistant host varieties and overcome plant resistance. The document discusses several mechanisms that generate variability in fungi, bacteria, and viruses, including mutation, transformation, transduction, conjugation, heterokaryosis, parasexualism, and recombination, which allow pathogens to adapt to new environments and hosts. Understanding pathogen variability is important for breeding disease-resistant crop varieties.
Impact of climate change on plant diseases.pptxPRAVINABARDE
Climate change is affecting plant diseases in several ways. Rising temperatures and changing precipitation patterns are altering the spread and severity of existing diseases while also introducing new disease threats. Pathogen virulence and survival rates are increasing under warmer conditions, while host resistance and disease management practices are becoming less effective. Successful disease management will require strategies adapted to the new climatic conditions, including developing resistant crop varieties and validating forecasting models under a changing climate.
i) Breeding crops for resistance to insects, diseases, and abiotic stresses like drought is important to reduce yield losses and costs of control measures.
ii) Mechanisms of resistance include non-preference, antibiosis, tolerance, avoidance, and physiological or biochemical traits like hairiness, toxins, or proline accumulation.
iii) Sources of resistance come from cultivated varieties, germplasm collections, and related wild species, and screening is done under field or controlled conditions.
Gene for-gene hypothesis & its validty in the present scenarioDr. Nimit Kumar
This document summarizes a seminar on disease development and resistance. It discusses the disease triangle, types of resistance, components of disease resistance including R and Avr genes, and Flor's gene-for-gene hypothesis. Molecular models of direct and indirect R-Avr gene interaction are presented. Examples of characterized R genes in crops like maize, rice, and tobacco are provided. Past work on disease resistance in flax at the university is summarized, as is current molecular characterization work in the department.
Drought stress and tolerance mechanisms in cropsMohaned Mohammed
Drought stress accounts for more crop production losses than any other factor. The presentation discusses the causes and effects of drought stress on plants and various tolerance mechanisms. It outlines that drought avoidance mechanisms include increased water absorption and transport, deep root systems, and reduced transpiration. Physiological responses include osmolyte accumulation, antioxidant production, and hormonal changes. Developing crops with drought tolerant traits through both conventional and molecular breeding approaches will be important for improving productivity under increasing drought conditions from climate change.
1) The gene for gene hypothesis states that for each resistance gene in the host plant, there is a corresponding avirulence gene in the pathogen. When the two match, the plant is resistant and disease does not occur.
2) When a new resistant variety is developed and widely grown, it creates a "boom and bust cycle" - as the variety booms in popularity, it puts selection pressure on the pathogen population that favors strains that can overcome its resistance, leading to an epidemic that causes the variety's popularity to bust.
3) The "Vertifolia effect" occurs when a variety's resistance is overcome by new pathogen strains, as happened with the potato variety Vertifolia - its resistance
1. What is pathogen variability?
2. Significance of pathogen Variability
3. Stages of variation
4. Mechanism of Variability in fungi
5. Characterization of variability among plant pathogens
The document discusses the development of Phytophthora and Pythium databases to support the identification and monitoring of these major plant pathogen groups. It describes the objectives of building a cyberinfrastructure to archive genotype, phenotype and distribution data on Phytophthora species/isolates. The Phytophthora Database provides tools for sequence analysis, phylogenetic analysis and molecular identification. Future directions include expanding to other plant pathogen databases and integrating genomic and geospatial data.
Effects of climate change on plant disease scenarioShamsher Alam
The document discusses the effects of climate change on plant diseases. It describes how increased greenhouse gas emissions and global warming are altering weather patterns and affecting plant-pathogen interactions. Specifically, it notes that higher carbon dioxide levels and temperatures are increasing canopy sizes and disease susceptibility. Changes in moisture levels and precipitation patterns are also influencing the spread and prevalence of various fungal and bacterial diseases. The document concludes by calling for more sustainable agricultural practices and novel disease management strategies that can help address plant health challenges under continuing climate change.
This presentation gives the insight idea about drought and its effect on the plant system also talks about development of drought-tolerant variety for ensuring food security.
plant drought effects, mechanisms and managementG Mahesh
This presentation provides an overview of plant drought stress, including its effects, mechanisms, and management strategies. Drought stress can impact plant growth, yield, water relations, photosynthesis, nutrient uptake, and cause oxidative damage. Plants have developed morphological, physiological and molecular mechanisms to tolerate drought, such as escaping dry conditions, reducing water loss through stomatal control, antioxidant production, and accumulating compatible solutes. The presentation also discusses strategies to manage drought, including improving crop genotypes and optimizing agronomic practices to enhance drought resistance.
Importance of epidemics in mono and poly cyclic diseases caused by various plant pathogens and the mathematical models for studying the strategy of those epidemics
Introduction importance scope and objectives of plant pathologyAnurAg Kerketta
This document provides an introduction to the field of plant pathology by defining it as the study of plant diseases, their causes, and management. It discusses how plant pathology relates to other sciences and its key objectives, which include studying the etiology, pathogenesis, epidemiology, and control of plant diseases. The document emphasizes the importance of plant pathology, noting that diseases cause billions in annual crop losses worldwide. It provides examples of historical famines and epidemics caused by plant diseases. Finally, it outlines the broad scope of plant pathology in surveying, identifying, assessing, and developing management strategies for economically important plant diseases.
Effect of climate change on crop pest interactions, area shift, food producti...Sunil Kumar
This document summarizes the effects of climate change on the interactions between crop pests and diseases. It discusses how higher temperatures and altered precipitation patterns may favor the proliferation of insect pests and change the spread of plant diseases. Climate change can influence host-pathogen interactions and affect disease management. It may also lead to range shifts of pests and the northward expansion of some diseases. Increased focus is needed on how climate change will affect the evolution of hosts and pathogens over time.
Climate change is altering plant disease development through its effects on the disease triangle of pathogens, hosts, and the environment. Rising CO2 levels can both increase pathogen growth and modify plant defenses. Higher temperatures can influence pathogen virulence and host resistance. Changes in precipitation patterns impact moisture levels and thus disease occurrence. Climate change is modifying the effectiveness of disease management approaches like fungicides. More research is still needed to fully understand and address the impacts of climate change on plant health.
Avs impact of climate change on plant diseasesAMOL SHITOLE
Climate change is impacting plant diseases in several ways. Rising temperatures and changing precipitation patterns are altering the environment in which plant pathogens develop. Higher temperatures can increase the number of pathogen generations per season, while changes in rainfall can make plants more susceptible to infection. These changes are interfering with plant resistance and affecting the efficacy of disease management strategies. Adaptation will require improved understanding of host-pathogen interactions under varying climate conditions, as well as long-term monitoring of pathogen and disease distributions as the climate continues to change.
INOCULUM DYNAMICS, POPULATION BIOLOGY OF PATHOGENsunilsuriya1
**Inoculum Dynamics and Population Biology of Plant Pathogens:**
The study of inoculum dynamics and the population biology of plant pathogens is integral to understanding the patterns of disease spread, severity, and persistence in agricultural ecosystems. Here's a closer look at these concepts:
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**1. Inoculum Dynamics:**
- **Definition:** Inoculum refers to the source of pathogenic organisms that initiate disease. This can include spores, mycelium, seeds, or any other form of the pathogen that can infect a susceptible host.
- **Sources:** Inoculum can come from various sources, including infected plant debris, soil, seeds, insects, and other infected plant material. Understanding the sources and availability of inoculum is crucial for predicting disease outbreaks.
- **Seasonal Fluctuations:** Inoculum levels often fluctuate seasonally due to changes in environmental conditions. For instance, certain pathogens may produce more spores during periods of high humidity or temperature.
- **Survival and Dispersal:** Pathogens have evolved various strategies for survival and dispersal. Some pathogens can survive for extended periods in soil or on plant debris, while others rely on wind, water, insects, or human activity for dispersal to new host plants.
- **Quantification:** Methods for quantifying inoculum levels include spore trapping, soil sampling, and molecular techniques such as PCR (Polymerase Chain Reaction) assays.
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**2. Population Biology of Plant Pathogens:**
- **Population Growth:** Pathogens exhibit characteristic population growth patterns influenced by factors such as host availability, environmental conditions, and pathogen biology. The growth rate of a pathogen population depends on the rate of reproduction, dispersal, and host infection.
- **Epidemiological Patterns:** Pathogen populations often follow classic epidemiological patterns, including exponential growth, peak incidence, and decline. This is influenced by factors such as host susceptibility, pathogen virulence, and environmental suitability.
- **Host-Pathogen Interactions:** The dynamics of pathogen populations are shaped by interactions with host plants. Host resistance mechanisms, such as genetic resistance or induced systemic resistance, can reduce pathogen populations, while susceptible hosts can fuel pathogen growth.
- **Genetic Diversity:** Pathogen populations can exhibit genetic diversity, leading to differences in virulence, pathogenicity, and the ability to overcome host resistance. This genetic variability influences disease dynamics and the effectiveness of control measures.
- **Adaptation and Evolution:** Pathogens have the ability to adapt to changing environmental conditions and host defenses through natural selection. This can lead to the emergence of new strains or races with increased virulence or the ability to overcome resistant plant varieties.
---
**Significance and Applications:**
- **Disease Prediction:**
Effect of Climatic Change on Harmful insect pests and Beneficial insectsmogiliramaiah
This document discusses the effects of climate change on insect pests. It notes that increasing temperatures can lead to insects expanding their geographical ranges, having additional generations per year, and higher survival rates. This allows pests to invade new areas and potentially outbreak. The document also discusses how fluctuating temperatures specifically can impact insect development times, overwintering patterns, and survival. Higher temperatures often result in faster development and reduced overwintering mortality.
EFFECT OF WEATHER FACTORS ON PLANT DISEASE DEVELOPMENTBalamurugan K
This document discusses the epidemiology of disease development and the effects of various weather factors. It summarizes that disease is caused by biotic and abiotic factors, including temperature, moisture, wind, rainfall and light. Each weather factor can influence pathogens and disease development in different ways. For example, higher temperatures can increase pathogen aggressiveness while also affecting plant resistance. Moisture is important for spore germination and spread of pathogens. Wind aids in dispersal of fungal spores and bacteria over long distances. Certain diseases are more prevalent in areas with high rainfall. Light levels can increase or decrease plant susceptibility depending on the pathogen.
IMPACT OF CLIMATIC PARAMETERS ON PATHOGEN, INSECT PESTS AND CROP PRODUCTIVITY santosh banoth
Plant diseases occur in all parts of the world where plants grow. For a disease to occur and to develop optimally, a combination of three factors must be present. susceptible plant, infective pathogen and favorable environment.
This document provides an introduction to the course PPATH 503: Epidemiology and Forecasting of plant disease. It defines key epidemiological terms like epidemic, defines the basic components of a disease epidemic including the host, pathogen, environment and how they interact. It discusses different types of pathogen cycles including monocyclic, polycyclic and polyetic. It explains disease progress curves and how to measure disease severity and incidence. The importance of epidemiology for disease management is highlighted. New molecular tools for epidemiological studies are also introduced.
Effect of climate change on plant diseaseKrishna Shah
Climate change is affecting plant diseases in several ways. Rising carbon dioxide levels can encourage denser plant canopies that favor certain diseases. Higher temperatures can increase pathogen growth and aggressiveness for some diseases. Increased moisture from more frequent rainfall or humidity provides favorable conditions for many fungal and bacterial pathogens. Wind can help spread spores and pathogens over longer distances. Climate change is also shifting the ranges of some pathogens. Adaptation strategies include integrated disease management, early warning systems, breeding more resistant varieties, and preventing invasive pathogens. The impacts on individual plant diseases from climate change may be positive, negative, or neutral, making predictions of future outbreaks more difficult.
The document provides an overview of plant disease epidemiology and summarizes key concepts. It defines an epidemic as "a change in disease intensity in a host population over time and space" and explains that epidemiology is the study of disease in populations, including the spread and factors influencing epidemic occurrence. It discusses different types of pathogens like monocyclic, polycyclic, and polyetic pathogens and how they impact disease cycles. Elements that influence epidemics like the host, pathogen, environment, time, and human factors are presented. Disease progress curves and methods of measuring disease in populations are also summarized.
Effect of climate change on crop pest interactionversha kumari
Climate change also disrupts and alters the distribution of pests and diseases, which poses a threat to agriculture. Climate change will also modify host physiology and resistance, and alter the stages and rates of the development of pests. IPM provide enough flexibility by which we will able to deal with many of the pests.
The document discusses the role of enzymes, toxins, and growth regulators in plant pathology and disease development. It defines plant pathology and describes how diseases develop through a complex process influenced by environmental factors and stress. The summary is:
1) Plant pathology studies plant diseases and their causes and controls. Disease develops through interactions between pathogens, hosts, and the environment.
2) Key stages of disease development include inoculation, penetration, infection, pathogen growth and reproduction, and dissemination. Disease occurs when conditions are suitable for the pathogen but not the host.
3) Factors like temperature, moisture, light, soil properties, and wind influence disease development by affecting the pathogen, host, or their interaction. Understanding
Climate change is causing rising global temperatures which can affect vectors and the diseases they transmit in several ways. Higher temperatures can increase vector populations, shorten pathogen incubation periods in vectors, and expand the transmission seasons or geographic ranges of certain diseases. Changes in precipitation patterns from climate change can also impact vectors by altering larval habitats or humidity levels. Models project that 5-30% of parasite species could face extinction due to climate-driven habitat loss, with potentially profound effects on ecosystems since vectors play important regulatory roles and support biodiversity. Diseases spread by mosquitoes, ticks, and other arthropods already cause millions of cases annually worldwide. Climate change may further drive emergence and reemergence of certain vector-borne diseases as temperatures rise
This document provides compiled lecture notes on plant disease epidemiology for a graduate program at Haramaya University in Ethiopia. It covers various topics related to plant disease epidemiology including factors of epidemics, modeling and temporal analysis of epidemics, and spatial analysis of epidemics. The introduction defines plant disease epidemiology and discusses its relevance to disease management. Subsequent sections discuss factors that influence epidemics including host, pathogen, environmental, and human factors. The document emphasizes the importance of monitoring and quantifying these different factors. Later sections cover modeling temporal and spatial changes in epidemics and assessing crop losses.
This document discusses the impacts of climate change on insect pests. It begins with definitions of climate change and its causes, including both natural factors and human activities that increase greenhouse gases. Sections then examine how rising temperatures, CO2 levels, and changes in precipitation patterns can indirectly and directly affect insect populations, ranges, development, and interactions with plants. Specifically, climate change may lead to faster insect growth, expanded ranges, altered life cycles, and increased outbreaks. The conclusion states that predicting climate change impacts is complex, as some factors may help or harm different insects, requiring further research on species' sensitivities.
This document discusses key concepts in plant disease epidemiology. It defines epidemics as widespread disease affecting many individuals over a large area in a short time. Endemic diseases constantly occur year after year, while pandemics involve mass mortality over continents. Sporadic diseases occur irregularly over limited areas. Epidemics follow disease progress curves from an initial destructive phase to a decline phase. They are influenced by factors like the pathogen, host, environment, and human activities. The interaction of these factors forms the basis of disease triangles and tetrahedrons.
This document provides an overview of plant disease epidemiology. It defines epidemiology as the study of disease outbreaks (epidemics) in plant populations over time and space, influenced by the interaction of pathogens, hosts, and environments. Key concepts covered include epidemic patterns (slow vs. fast), factors influencing epidemics (host susceptibility, pathogen quantity/type, environment), measurement of disease progression through curves, and historical examples of major epidemics like the Irish potato famine. The document emphasizes that understanding epidemiology is important to predict disease spread and impact.
This document provides course materials for a plant pathology epidemiology course, including:
- 7 topics that will be covered in the course ranging from introduction to epidemiology to forecasting plant diseases.
- Details on course materials which will include recent books, journal articles, and PowerPoint presentations.
- Evaluation criteria including analyzing disease parameters, article reviews, and a written examination.
Aelsdeep Singh Mann Impact of Global Warming On insects THES.docxnettletondevon
Aelsdeep Singh Mann
Impact of Global Warming On insects
THESIS- Global warming is a great concern throughout the world. In nature insects are greatly affected by changing temperature. Insect will experience additional life cycles with rapid growth rate. Because of changes in the population dynamics including distribution and migration the reliability on current insect pest ETL will be reduced. Increased insect pests outbreak will affect agricultural production. Research on basic biology of insect, population dynamics and behavior patterns should be focused to ascertain the effect of global warming on insect behavior Because the insects serve as a warning for other global warming effects.
Generally global warming refers to an increase in average global temperatures. There are many gases like nitrous oxide, methane, nitrogen in atmosphere which keeps the earth warm and cause global warming or greenhouse effect. Global warming is caused by natural as well as human activities. There are number of natural factors responsible for climate change. Some of the most prominent are volcanoes, ocean currents, forest fires etc. Among human activities, emissions of greenhouse gases, industrialization, deforestation, fuel burning, etc. are most important factor contributing towards global warming. It is not new that global warming can affect agriculture through their direct and indirect effects on the crops, soils, livestock, and pests. So, because of global warming insects are effected in many ways. Increased temperature has resulted in increased northward migration of some insects, insect development rate and oviposition, potential for insect outbreaks, invasive species introductions and insect extinctions because, insects are able to respond rapidly to climate changes and adapt to the changing environment due to high reproductive potential and relatively short generation time. Here are some examples of researches conducted in ISRAEL of the species of insects named (Orius). These are the bugs which are mostly generalist predators commonly found in flowers of herbaceous vegetation In this study, there was a Comparison of the relative abundance of Orios species revealed significant differences among years (G12= 1060.2, P,0.0001). The relative abundance of O. laevigates has decreased from 50%, 38% and 60% during 1940–59, 1960–79 and 1980–99, respectively, to 4–6% during 2001–2 and the present survey. In contrast, the relative abundance of O. abidingness has increased gradually from 9% and 1% during 1940–59 and 1960–79, respectively, to 26% during 1980–99 and 65% and 62% in 2001–2 and in the present survey, respectively. There are other effect on the insects listed below
· Effect of global warming on insect biology: Temperature is probably the single most important abiotic factor influencing insect biology. Pests may become more active than they currently are, thus posing the threat of greater economic losses to farmers. It has been estimated that wit.
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2. INTRODUCTION
• Climate change is a major environmental challenge worldwide. Green house
gases (GHG) viz., water vapour (H2O), carbon dioxide (CO2), Methane (CH4),
nitrous oxide (N2O), hydrofluorocarbons (HFCs) and Ozone (O3) in the
atmosphere trap reflected radiation to warm the earth surface (Mahato, 2014).
• Human activities are widely involved in increasing global climate changes that
directly influences the ecology (Pachauri and Reisinger, 2007 and Ahanger et al.,
2013).
• According to Inter-govenrmental Panel on Climate Change (IPCC, 2007); the
planet earth is experiencing a climate change and atmospheric CO2 is a major
GHG, which increased by nearly 30% and temperature by 0.3- 0.6°C.
3. • This global climate changes by various factors (Pachauri and Reisinger, 2007 and
Pachauri et al., 2014) and change or influence all the 3 major elements of disease
triangle, viz., host, pathogen and environment (Legreve and Duveiller, 2010).
• Crop growth and production can be significantly affected due to high atmospheric
CO2 concentration, temperature, changes in precipitation patterns and frequency
of extreme weather phenomena and diseases presence will altered under these
condition (Rosenzweig and Tubiello, 2007, Ghini et al., 2008 and Chakraborty,
2011).
• When the host present pathogens with short life cycles, reproduction rates is high
and dispersion mechanisms respond quickly and adapt faster to climate change
(Coakley et al., 1999).
4. • Climate change would affect plant diseases together with anthropogenic
processes such as air, water and soil pollution, long-distance introduction of
exotic species and urbanization (Regniere, 2012).
• These factors contribute to the spread of diseases viz. sudden oak death
(Prospero et al., 2009). Elevated temperature and CO2 concentration have
impact on plant-disease interaction (Lopez et al., 2012) and posing a higher
threat perception of late blight (Phytophthora infestans) of potato and blast
(Magnaporthe grisea) and sheath blight (Rhizoctonia solani) of rice (Kobayashi
et al., 2006).
5.
6. EPIDEMIC Change in disease intensity in a host
population over time and space.
EPIPHYTOTIC
Unger (1833), Whetzel (1920's)
Being a plant disease that tends to recur
sporadically and to affect large numbers of
susceptible plants.
EPIDEMIOLOGY Science of disease in populations.
Vanderplank(1963)
• Study of the spread of diseases, in space
and time, with the objective to trace factors
that are responsible for, or contribute to,
epidemic occurrence.
7. HISTORY (ANCIENT TO MODERN TIMES)
Hippocrates (~400 BC) : First use of "epidemic", widespread disease (human
disease.
Theophrastus (~340 BC) : Plant diseases in fields, Environmental influences
Pliny (~50 AD) : Plant diseases; soil; climate.
Duhamel de Monceau : Disease progress curves.
(1728 AD)
Late 19th Century and forward…
Kuhn (1858) - 1st textbook of plant pathology.
Ward (1901): Book "Diseases in Plants" emphasized ecology
(populations) of disease.
Jones (1913) - Role of the environment.
Gaumann (1946): "Principles of Plant Infection” -Disease spread, -
Conditions leading to an epidemic, -'Infection Chain' (=
disease cycle),-compare with medicine (disease of
humans).
8. Large(1952, andothers)
-Disease progress curves
-Crop losses
-Disease assessment (measurement)
Horsfall & Dimond (1960)- "Plant Pathology,
Volume 3"
-Populations
-Inoculum density:disease relations
-Spore dispersal
-Analysis (mathematics)
-Forecasting, prediction
-Traditional definition ---> Modern
definition
Gregory(1963, 1973)
"The Microbiology of theAtmosphere"
-spore dispersal, disease spread
Aerobiology
Vanderplank (1963) (usedto be van
der Plank)
"Plant Diseases: Epidemics and
Control"
-Populations
-Rates (dynamic processes)
-Analysis, mathematics
-Models, theory
-Link epidemiology and control
-Established the science of plant
disease epidemiology
Other pioneers:
Zadoks (1960-1995), TheNetherlands
Kranz (1968-1995),Germany
Waggoner (1960-mid --1980s),USA
S. Nagaranjan1983-India
9. ELEMENTS OF AN EPIDEMIC
1) Host
2) Pathogen
3) Environment
Interactions of the 3 main
components are described by
the disease triangle.
The Disease Triangle
Disease development is also affected by
4. Time
5. Humans
Disease Tetrahedron
Interactions of the 5
components are described by
the disease pyramid.
10.
11.
12. HOST FACTORS
All plants can be considered hosts.
o Degree of genetic uniformity.
o Age – affects disease development depending on plant-pathogen
interaction.
There are different levels of susceptibility, which include:
o Immune - cannot be infected.
o Susceptible - can be infected.
o Resistant - may or may not be infected.
13. ENVIRONMENTAL FACTORS
i. Moisture
-Rain, dew, high humidity.
-Dominant factor in diseases
caused by oomycetes, bacteria &
nematodes.
ii.Temperature
- Affects disease cycles of
pathogens
Diseasedevelopment is also
affected by
Time factors
• Season of the year
• Duration & frequency of
favorable temp. & rains
• Appearance of vectors, etc.
Humans
How HumansAffect Development of
Epidemics
• Site Selection & Preparation.
• Selection of Propagative Material.
• Introduction of Exotic Pathogens.
• Cultural Practices.
• Disease control measures.
14. CLIMATE CHANGE & MICROBIAL INTERACTIONS
i. Nitrogen deposition level, CO2 concentration and temperature are
important factors affecting soil microbial communities (Garret et al.,
2006).
ii. Increased CO2 levels in the atmosphere have major consequences on
carbon cycling and the functioning of various ecosystems.
iii. Short-term and long-term changes in the abiotic conditions not only
affect plant growth and productivity but also the populations of
microorganisms living on plant surfaces.
iv. Any change in phyllosphere microflora, affects plant growth and
plants’ ability to withstand aggressive attack of pathogens.
15. EFFECT OF TEMPERATURE
Certain minimum temperature is required by both plants and
pathogens to grow. Temperature affects the chain of events in
disease cycles such as survival, dispersal, penetration,
development and also reproduction rate for many pathogens.
Generally high moisture and temperature favours and initiate
disease development, as well as germination and
proliferation of fungal spores of diverse pathogens (Agrios,
2005).
16. EFFECT OF TEMPERATURE
• Plants, as well as pathogens, require certain minimum temperatures to
growandcarryout their activities.
• At higher temperatures, pathogens become active and, they can infect
plants andcausedisease.
• Cankerdiseasesof perennial plants causedby:
fungi Nectria, Leucostoma (Cytospora), the oomycete
Phytophthora
bybacteriasuchas Pseudomonas,
• Infections beginanddevelop primarily in earlyspring or in thefall.
• During these periods the temperatures are high enough for these fungi
to growwell but aretoo low to allow optimum hostdevelopment.
17. TEMPERATURE AFFECTS:
1. The number of spores formed in aunit plant
area.
2. The number of spores released in a given time
period.
18. • Due to changes in temperature and precipitation, climate change may
alter the growth stage, development rate, pathogenicity of infectious
agents, and the physiology and resistance of the host plant
(Charkraborty and Datta, 2003).
• Sunlight affects pathogens due to the accumulation of phytoalexins or
protective pigments in host tissue.
• Host plants such as wheat and oats become more susceptible to rust
diseases with increased temperature; but some forage species become
more resistant to fungi with increased temperature (Coakley et al.,
1999).
19. • With increasing temperature spore germination of rust fungus Puccinia substriata
increases (Tapsoba and Wilson, 1997).
• In southern Germany, a northward shift of Cercospora beticola, leaf spot of sugar
beeet was due to increasing annual mean temperature by 0.8-1°C (Richerzhagen
et al., 2011).
• Altered temperatures favour over-wintering of sexual propagules which increased
the evolutionary potential of a population (Pfender and Vollmer (1999).
• Conidia of powdery mildew have the ability to germinate even at 0% relative
humidity (RH) (Yarwood, 1978).
• Conidia of Erisiphe cichoracearum germinate at temperature from 7 to 32°C with a
RH of 60 to 80% (Khan and Khan, 1992); and spores of Erysiphe necator germinate
at temperatures from 6 to 23°C with a RH from 33 to 90 % (Bendek et al., 2007).
20. • Phytophthora infestans, late blight of potato and tomato, infects and
reproduces most successfully at high moisture when temperatures
are between 7.2°C and 26.8°C.
• Infection of Eucalyptus sp. by Phytophthora cinnamomi due to
increased soil temperature of 12-30°C (Podger et al., 1990).
• Even the incidence of virus and other vector borne diseases also alter.
Mild and warmer winters make aphids easy to survive thus
spreading Barley yellow dwarf virus (BYDV) and also increase viruses
of potato and sugar beet (Thomas, 1989; Mackerron et al., 1993).
21. RISK ANALYSIS STUDIES ON THE EFFECTS OF CLIMATE CHANGE
STUDY RESULT REFERENCE
• In the UK, the effects of climate
change on Phoma (Leptosphaeria
maculans) were assessed.
Epidemics will not only increase in
severity but also spread northwards by
the 2020s.
Evans et al., 2007
• Future scenarios of downy mildew
on grapevine (Plasmopara viticola)
were simulated from the results of
two climate change models. The
results suggested that the incidence
of disease would increase and the
production of grapes in
northwestern Italy would decrease.
Predicted an increase of the disease
pressure in each decade to
consequence of more favorable
temperature conditions.
Salinari et al., 2006
• A model to assess the severity of
Phytophthora infestans under
climate change was developed
A marked shift of the disease in the
infestation pressure to higher altitude
Kocmankova et al., 2007
22. STUDY RESULT REFERENCE
The effects of elevated levels
of CO2 and temperature on
the incidence of four major
chili pepper diseases
(Anthracnose
(Colletotrichum acutatum)
Phytophthora blight
(Phytophthora capsici))
and
• two bacterial diseases
(bacterial wilt (Ralstonia
solanacearum) and
bacterial spot
(Xanthomonas campestris
pv. vesicatoria)) were
determined.
Elevated CO2 and
temperature significantly
increased the incidence of
two bacterial diseases.
Anthracnose decreased and
Phytophthora blight slightly
increased.
Shin and Yun, 2010
23. A summary of the influence of elevated Temperature on some Host and Pathogen Interaction
CROP/HOST DISEASE/PATHOGEN CLIMATE CHANGE CHANGE IN DISEASE
SEVERITY
AUTHOR/REFERENCE
Wheat Stripe rust – Puccinia
striiformis
Elevated average annual
temperature
Decrease Yang et al., 1998
Wheat Dwarf bunt- Tilletia
controversa
Elevated temperatures Increase Boland et al., 2005
Wheat Wheat Stripe rust –
Puccinias triiformis
Higher Temperature Increase Milus et al., 2006
Citrus Anthracnose-
Colletotrichum acutatum
Elevated Temperatures Increase Jesus Junior et. al., 2007
Potato Late blight – Phytophthora
infestans
Elevated temperatures
causing earlier seasons
Increase Hannukkala et al., 2007
Papaya Asperisporium caricae Elevated temperatures and
lower relative humidity
Decrease Jesus Junior et. al., 2007
Pineapple Fusarium subglutinans Elevated temperatures Decrease Matos et al., 2000
Coffee Meloidogyne incognita Elevated temperatures Increase Ghini et al., 2008
24. EFFECT OF CO2
a. Increased size of plant organs, leaf area, leaf thickness, more numbers of leaves,
higher total leaf area/plant, stems and branches with greater diameter are
resulted from increased CO2 levels (Bowes, 1993 and Pritchard et al., 1999).
b. Dense canopy favours the incidence of rust, powdery mildew, Alternaria blight,
Stemphylium blight and anthacnose diseases.
c. Higher CO2 concentrations induce greater fungal spore production. Increased
CO2 also enhances photosynthesis, increased water use efficiency and reduced
damage from ozone (von Tiedmann and Firsching, 2000); and leaf area, plant
height and crop yield are increased at higher doses of CO2 (Eastburn et al., 2011).
d. The physiological changes on the host plant due to increased CO2 can conversely
result in increase host resistance to pathogens (Coakley et al., 1999).
25. EFFECT OF C02
i. Under elevated CO2 conditions, potential of dual mechanism i.e., reduced
stomata opening and altered leaf chemistry results in reduced disease
incidence and severity in many plant pathosystems where the pathogen targets
the stomata (Mcelrone et al., 2005).
ii. In soybean, elevated concentration of CO2 and O3 altered the expression of 3
soybean diseases, downy mildew (Perenospora manshurica), brown spots
(Septoria glycines) and sudden death syndrome (Fusarium virguliforme)
(Eastburn et al., 2010).
iii. Elevated CO2 also leads to production of papillae and accumulation of silicon
by barley plants at the site of appressorial penetration of Erysiphe graminis
and changed leaf chemistry that decrease susceptibility to the powdery
mildew pathogen (Hibberd et al., 1996).
26. EFFECT OF INCREASED CO2 CONCENTRATIONS ON PATHOGENS
STUDY RESULT REFERENCE
• The effect of elevated concentrations
of CO2 on the infection of barley by
Erysiphe graminis was determined.
The percentage of conidia that progressed
to produce colonies was lower in plants
grown in 700 than in 350ppm CO2.
Hibberd et al. (1996)
• Interactive effects of elevated CO2 and
O3 levels on wheat leaves infected
with leaf rust fungus Puccinia triticina
were described.
Elevated CO2 increased the
photosynthetic rates of the diseased
plants by 20 and 42% at the ambient and
elevated ozone concentrations,
respectively.
Tiedemann and Firstching (2000).
• The effects of elevated CO2
concentrations on the development of
Phytophthora parasitica (root rot) in
tomato were evaluated.
The extra CO2 completely
counterbalanced the negative effect of
the pathogenic infection on overall plant
productivity.
Jwa and Walling (2001).
• Pyricularia oryzae Cavara and
Rhizoctonia solani Kühn were
evaluated.
Rice plants grown in an elevated CO2
concentration were more susceptible to
leaf blast than those in ambient CO2.
Kobayashi et al. (2006).
27. STUDY RESULT REFERENCE
• The effects of carbon dioxide (CO2)
and ozone (O3) on three soybean
diseases (downy mildew, Septoria
and sudden death syndrome) were
determined in the field.
Changes in atmospheric composition
altered disease expression. Elevated CO2
reduced downy mildew disease
severity. But increased brown spot
severity and without effect in sudden
death syndrome.
Eastburn et al. (2010).
• The response of tobacco to potato
virus Y was evaluated.
The titre of viral coat-protein was
markedly reduced in leaves under these
conditions at both nitrogen levels. The
accumulation of phenylpropanoids,
may result in an earlier confinement of
the virus at high CO2.
Matros et al. (2006).
• The germination rates of conidia of
C. gloeosporioides were determined.
spore germination was reduced and
extended incubation period was at 700
ppm, and Anthracnose severity was
reduced.
Chakraborty et al. (2002).
28. EFFECT OF MOISTURE
• It influences the initiation and development of infectious plant
diseasesin many interrelatedways.
Moisture is indispensablefor:
The germination of fungalspores
Penetration of the host by the germ tube
Activation of bacterial, fungal, and nematode pathogens
before they caninfect theplant.
The spread of pathogens on the same plant and from one plant to
another
• Moisture increases the succulence of host plants and thus their
susceptibility to certain pathogens, which affects the extent and
severity ofdisease.
29. EFFECT OF MOISTURE
With increased temperature extreme rainfall events and higher atmospheric
water vapour concentrations take place.
i. These encourage the crops to produce healthier and larger canopies that
retain moisture as leaf wetness and RH for longer periods and results in
condition conducive for pathogens and diseases such as late blights and
vegetable root diseases including powdery mildews (Coakley et al., 1999).
ii. High moisture favours foliar diseases and some soil borne pathogens such
Phytophthora, Pythium, R. solani and Sclerotium rolfsii.
iii. Drought stress affect the incidence and severity of viruses such as Maize
dwarf mosaic virus (MDMV) and Beet yellows virus (BYV) (Olsen et al.,
1990 and Clover et al., 1999).
30. EFFECT OF WIND
Wind influences infectious plantdiseases:
• primarily by increasing the spread of plant pathogens and the
number of wounds on host plants.
• to a smaller extent, by accelerating the drying of wet surfaces of
plants.
• fungi, bacteria, and viruses that are spread either directly by the
wind or indirectly by insect vectors that can themselves be
carried over long distances by thewind.
• wind-blown rain helps release spores and bacteria from infected
tissue and then carries and deposits them on wet surfaces of
plants, which, if susceptible, can be infected.
31. EFFECT OF LIGHT
• The intensity and the duration of light may either
increase or decrease the susceptibility of plants to
infection.
• Low light produces etiolated plants, which
increases the susceptibility of plants to non
obligate parasites.
Tomato plants to Botrytis or to Fusarium.
• Reduced light intensity generally increases the
susceptibility of plants tovirus infections.
• Low light intensities following inoculation tend to mask
the symptoms of somediseases.
32. EFFECT OF SOIL pH & SOIL STRUCTURE
• The pH of the soil is important in the occurrence and
severity of plant diseases caused by certain soil borne
pathogens.
Clubroot of crucifers (Plasmodiophorabrassicae)
severe -pH 5.7
drops between pH5.7 -6.2 and
completely checked -pH7.8.
Cotton root rot fungus (Phymatotrichopsis omnivora)
exists only in soils contain relatively high
concentrations of calciumcarbonate.
33. EFFECT OF HOST-PLANT NUTRITION
Nutrition affects the rate of growth and the state of readiness
of plants.
• Nitrogen: abundance results in the production of young,
succulent growth, a prolonged vegetative period, and
delayed maturity of the plant, make the plant more
susceptible topathogens.
• Phosphorus: increase resistance by improving the
balance of nutrients in the plant or by accelerating the
maturity of the crop and to escape infection by
pathogens that prefer younger tissues.
34. Potassium :
• Have a direct effect on pathogen establishment and
development in thehost.
• And an indirect effect on infection by promoting wound
healing.
• Potassium also increases resistance to frost injury.
Calcium: Effects the composition of cell walls and their
resistance to penetrationby pathogens.
Various micronutrients (Fe, Cu,Mn,Mg,Si) showed decreased
infection when levels of nutrients increased.
35. EFFECTOF
HERBICIDES
AND AIR
POLLUTANTS:
i. The direct effects may include
stimulation or retardation of the
growth of the pathogen or in the
susceptibility of the host.
ii. Indirect effects include effect on
activity of soil microflora, elimination
or selection of the pathogen by
certain alternate hosts, or alteration
of the microclimate of the crop plant
canopy.
iii. ozone, can affect a pathogen and
sometimes the disease it causes. The
rate of infection is reduced if the
exposure to ozone is early but is
increased if exposure occurs late.
36. EFFECT OF CLIMATE CHANGE ON VECTOR-
BORNE DISEASES
i. The risk of vector-borne disease at the local and regional level is limited by the
climatic requirements of disease vectors (Malmstrom et al., 2011).
ii. Both host plant and insect-vector populations are affected by climate change
and spread the plant viruses (Jones, 2009).
iii. Climate change influences the primary infection of the host, the spread of the
infection within the host and/or the horizontal transmission of the virus to new
hosts by the vector along with phenology and physiology of the host thereby
affect its virus susceptibility and virus ability to infect.
iv. Climate change has various effects on vectors like modification of vector
phenology, vector’s over-wintering, density, migration and its stability.
49. RESEARCH NEEDS
1. The effectiveness of disease management strategies. Assessing current management strategies
and proposing alternatives will prepare us for the challenge of climate change. This will allow
our mitigation measures to be more efficient and adaptable to change.
2. The risk of disease must be analyzed to determine the geographical distribution and
modification of diseases due to climate change.
3. Plant diseases and crops must be modeled. Mathematical models can be used to perform
quantitative analysis of the phytosanitary problems. They provide a very powerful tool to
understand and represent interactions among weather, crop and disease variables (Allman and
Rhodes, 2004).
4. Mathematical models can help to assess the probability of introduction, reproduction and
dispersion of diseases, and the magnitude of their effects on crops yield and quality in current
scenarios and under climate change.
5. Factors limiting the survival of pathogens should be characterized (e.g., temperature, humidity,
CO2, O3 and radiation).
50. CONCLUSION
• Climate change is an important phenomenon that affects agricultural
production. By anticipating the future, we can prepare ourselves for problems
caused by climate change, especially those related to agricultural activities.
• Global warming may modify areas affected by pests and diseases, studies must be
performed to assess pest and disease stages under the effects of climate
change, determine the magnitude of disease and identify measures to minimize
the risk of infection.
• Exposure to altered atmospheric conditions can modify fungal disease expression.
Studies had shown that exposure at elevated CO2 increases disease incidence or
severity in some cases but in other cases decreased.
51. • These highlight how the host–pathogen interactions make it
difficult to devise general principles that govern changes across
fungal pathosystems. So increase or decrease disease will be in
function of the host and pathogen.
• Climate change may affect the actual, spatial and temporal
distribution of diseases; however, the magnitude of these effects
remains unclear.
• Disease risk analysis based on host-pathogen interactions should
be performed, and research on host response and adaptation
should be conducted to understand how an imminent change in the
climate could affect plant diseases.