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.
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
In a computer simulation of an epidemic, the computer is given data describing the various sub components of the epidemic and control practices at specific points in time (such as at weekly intervals).Computer simulation of epidemics is extremely useful as an educational exercise for students of plant pathology and also for farmers so that they can better understand and appreciate the effect of each epidemic sub component on the final size of their crop loss.Simulators serve as tools that can evaluate the importance of the size of each epidemic sub component at a particular point in time of the epidemic by projecting its effect on the final crop loss.Computer simulation are expert systems,that try to equal and suppress the logic and ability of an expert professional in solving problems.Systems are used in plant pathology frequently for diagnosis of plant diseases.Systems can advice growers in making decisions on disease management in respect of kind, amount and time of application of pesticides etc.Simulators can decompose disease progress so they are used now to develop forecaster.
Effect of environment and nutrition on plant disease developmentparnavi kadam
BRIEF AND PRECISE POINTS ON PLANT DISEASE DEVELOPMENT. IT MOSTLY FOCUSES ON HOW THE FACTORS AFFECT THE MICROBES AND THEN THEIR MICROBIAL EFFECT ON DISEASE DEVELOPMENT.
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
In a computer simulation of an epidemic, the computer is given data describing the various sub components of the epidemic and control practices at specific points in time (such as at weekly intervals).Computer simulation of epidemics is extremely useful as an educational exercise for students of plant pathology and also for farmers so that they can better understand and appreciate the effect of each epidemic sub component on the final size of their crop loss.Simulators serve as tools that can evaluate the importance of the size of each epidemic sub component at a particular point in time of the epidemic by projecting its effect on the final crop loss.Computer simulation are expert systems,that try to equal and suppress the logic and ability of an expert professional in solving problems.Systems are used in plant pathology frequently for diagnosis of plant diseases.Systems can advice growers in making decisions on disease management in respect of kind, amount and time of application of pesticides etc.Simulators can decompose disease progress so they are used now to develop forecaster.
Effect of environment and nutrition on plant disease developmentparnavi kadam
BRIEF AND PRECISE POINTS ON PLANT DISEASE DEVELOPMENT. IT MOSTLY FOCUSES ON HOW THE FACTORS AFFECT THE MICROBES AND THEN THEIR MICROBIAL EFFECT ON DISEASE DEVELOPMENT.
Seed borne diseases are caused by micro-organisms infecting seeds. Seeds are attacked by various fungi, bacteria and viruses at various stages viz., in the field ,during processing, at the time of transportation, and during storage.
This ppt illustrates and describes the two bacterial diseases included in the BSc Hons Program Syllabys Core Course III or DSC 3- Citrus canker and angular leaf spot of cotton
Seed borne diseases are caused by micro-organisms infecting seeds. Seeds are attacked by various fungi, bacteria and viruses at various stages viz., in the field ,during processing, at the time of transportation, and during storage.
This ppt illustrates and describes the two bacterial diseases included in the BSc Hons Program Syllabys Core Course III or DSC 3- Citrus canker and angular leaf spot of cotton
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:
---
**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.
---
**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:**
Role of epidemiology in plant disease management^L.pptxaishnasrivastava
Plant disease epidemiology is the quantitative study of disease spread in plant populations, incorporating biological, statistical, agronomic, and ecological perspectives. It involves modeling and understanding factors influencing disease spread over time and space. While rooted in efforts to control plant disease, it now extends to predicting the impact of climate change on diseases like rice leaf blast, oak disease, grape downy mildew, and various forest diseases using weather data from climate change models.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
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This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
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http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2. Epidemic
Gr. Epi=upon, among and Demons=people
Epidemic What is among people
"Change in disease intensity in a host population over time and
space."
Change: often increase -- a dynamic process
Disease: dealing with diseases, not just the pathogen (or plant/crop)
Host: Organism infected (or potentially infected) by another organism
Population: a population phenomenon
Time and space: two physical dimensions of interest.
3. 3
Epiphytotic Unger (1833), Whetzel (1920's)
However, equally valid meaning from Greek:
"what is in (or among) a population" ("demio")
"Epidemic" used for plants for a long time…..
•1728: Duhamel 1691,1842: book titles
•1858: Kuhn 1901: Ward
Thus, no valid reason to use "epiphytotic“
Therefore the issue has been resolved!!!
NOTE:
If one used epiphytotic
(instead of
epidemic), then one
should use
epiphytotiology instead
of epidemiology!
-(Epiphytology is the
study of epiphytes).
4. Epidemiology
• Study of epidemics.
• Science of disease in populations. Vanderplank (1963)
• Ecology of disease.
• 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.
• The science of populations of pathogens in populations of host plants, and the
diseases resulting therefrom under the influence of the environment and human
interferences.
4
5. History (ancient to modern times)
Disease
5
Hippocrates (~400 BC): First use of "epidemic", widespread disease (human diseases
Theophrastus (~340 BC): Plant diseases in fields, Environmental influences
Pliny (~50 AD): Plant diseases; soil; climate
Duhamel de Monceau (1728 AD): Disease progress curves, Comparison of plant and
animal epidemics
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 leadin
to an epidemic, -'Infection Chain' (= disease cycle), -compare with medicine (diseases
of humans)
6. 6
Large (1952, and others)
-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 the Atmosphere"
-spore dispersal, disease spread
Aerobiology
Vanderplank (1963) (used to 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), The Netherlands
Kranz (1968-1995), Germany
Waggoner (1960-mid --1980s), USA
S. Nagaranjan 1983-India
Note: many developments in other fields…
Ecology, medical epidemiology,
Biomathematics, etc.
7. 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.
8. Elements of an Epidemic (cont’)
i. Genetic resistance or susceptibility of Host
–Vertical Resistance
–Horizontal Resistance
ii. Degree of genetic uniformity of host in a particular field
–Monoculture, especially Clones
–Natural, Intermingled Populations
iii. Type of crops
- Annual crops & foliar or fruit diseases develop much
more rapidly (in weeks)
- Perennial woody diseases take longer time to develop
(in years)
iv. Age of host plants
- Some plants are susceptible only during growth period
& become resistant during mature period
8
How the Plant Affects Development of Epidemics
9. How Pathogens Affect Development of Epidemics
i. Levels of virulence
–Faster Production of Larger # Inoculum
ii. Quantity of inoculum near hosts
iii. Type of reproduction of the pathogen
–Monocyclic
–Polycyclic
•Responsible for most Sudden, Catastrophic Epidemics
–Polyetic
iv. Ecology of the pathogen
–Reproduce on Surface of Aerial Parts of Plant
–Reproduce inside Plant
–Reproduce on Infected Plant Parts in Soil
v. Mode of spread of the pathogen
–Breezes or Strong Winds
•Most Sudden & Widespread Epidemics
–Inoculum Carried by Airborne Vectors
–Wind-Blown Rain
–Carried on Seed, Tubers, Bulbs
–Beetles
–Pathogens Spreading through Soil
•Usually Local, Slow-Spreading Diseases of Considerable Severity
Elements of an Epidemic (cont’)
10. Elements of an Epidemic (cont’)
3. Environmental factors
i. Moisture
- Rain, dew, high humidity
- Dominant factor in diseases caused by
oomycetes, fungi, bacteria & nematodes
ii. Temperature
- Affects disease cycles of pathogens
Disease development is also
affected by
4. Time
Time factors
Season of the year
Duration & frequency of favorable temp. &
rains
Appearance of vectors, etc.
5. Humans
Site Selection & Preparation
Selection of Propagative Material
Introduction of Exotic Pathogens
Cultural Practices
Disease control measures
I ntroduction of new pathogens or disease
How Humans Affect Development
of Epidemics
11. Monocyclic pathogen
A monocyclic pathogen completes
just one disease cycle per season.
primary inoculum is the only
inoculum available for the entire
season, and there is no secondary
inoculum and no secondary
infection.
Examples of Monocyclic
Diseases: Blackleg of potato
(Erwinia caratovora),
Verticilliumwilt, Cereal Cyst
Nematode.
11
Can you think of some examples
of monocyclic pathogens?
12. Monocyclic Disease
12
• Examples: smuts, rusts, which require two alternate hosts,
many soil-borne diseases, root rots and vascular wilts
• In general, there are three types of plant diseases that tend
to produce only one infection cycle per host cycle (1)
postharvest diseases, (2) diseases caused by soil-borne
plant pathogens, and (3) rusts without a urediniospore
stage.
13. Polycyclic pathogens/Disease
13
Pathogens that produce more than one (2 to 30) infection cycle per
crop cycle
Disseminate primarily by air or airborne vectors (insects)
Responsible for epidemics on most crops
downy mildews, late blight of potato, powdery mildews, leaf
spots and blights, grain rusts, and insectborne viruses.
15. Polyetic(multiyear) pathogens
In some diseases of trees,fungal vascular
wilts,phytoplasmal declines, and viral
infections, pathogen may not complete
a disease cycle, it may not produce
inoculum that can be disseminated and
initiate new infections, until at least the
following year and some may take
longer.
• Several rusts of trees and the
mistletoes,they attak several years to go
through all the stage sof their life cycle
and to initiate new infections. Dutch elm
disease, cedar apple rust, white pine
blister rust, and citrus tristeza
15
16. Disease Progress Curve
• The representation of plant disease over time is
referred to as a “Disease Progress Curve”.
16
WHY?
Compare control measures
‐ Compare effect of environment on disease development
‐ Predict future disease development
‐ Disease forecasting for improved control
21. 21
Measuring Disease in a Population
Disease incidence
Actual number or proportion of plants diseased
Number diseased out of total number of plants
observed
Disease severity
•Area of plant tissue affected by disease
•For many diseases, severity is the area of plant surface covered by lesions
•Measured using assessment scales or by determining the area under a disease
progress curve (AUDPC)
3. Yield loss
•The proportion of yield that the grower will not be able to harvest due to disease
•Results in economic loss
23. Epidemic Manganement
• Ways to reduce disease
(inoculum) at beginning (xo)
• Affects monocyclic and polycylic
diseases
• Fumigation Certified seed
• Sanitation Seed treatments
• Quarantine Host plant
resistance
• Ways to decrease the rate of disease
development (infection rate) (r)
• Change the environment
• Fertilizer application
• Pesticide Application
• Host plant resistance
• Ways to change t
• Harvest early before disease becomes
severe.
• Plant early (cereal cyst nematode)
23
24. Importance of Epidemiology
• The epidemiological study is essential for the formulation of control
measures for which no resistant variety is available and the farmers have to
rely of the chemicals and other sanitary measures.
• It undergirds the technology to disease management through understanding
disease behaviour over time and space.
• It accomplishes perspective governing disease management scheme.
• It protects bases for evaluating for an general disease management
scheme.
24
25. 25
1. Molecular tools
Polymerase Chain Reaction (PCR), Enzyme
Linked Immunosorbant Assay (ELISA), DNA
Fingerprinting, etc.
For rapid & accurate detection & identification
of pathogens
2. Data management
Geographic Information System (GIS), Global
Positioning System (GPS), Remote Sensing, etc.
To assist in disease control strategies
3. Disease modeling & forecasting
To predict the probability of outbreaks
New Tools in Epidemiology