This document discusses plant pathology, which is the scientific study of plant diseases caused by pathogens and environmental conditions. It addresses the causes of plant diseases, including living organisms like fungi, bacteria, viruses and nematodes, as well as non-living factors. The disease cycle and factors affecting disease development are also examined. Plant diseases can cause significant economic losses by reducing crop yields and quality. Understanding plant pathology is important for preventing diseases and maintaining food supply.
Prayers and sacrifices to gods for control of plant diseases
The mid-1600s, a species or variety was reported to be more resistant to a disease than another related species or variety.
Selection of resistant plants as a control of plant diseases.
This is likely to have occurred not only because seeds from resistant and therefore healthier plants looked bigger and better than those from infected susceptible plants, but also because in severe disease out breaks, resistant plants were the only ones surviving and, therefore, their seeds were the only ones available for planting.
Prayers and sacrifices to gods for control of plant diseases
The mid-1600s, a species or variety was reported to be more resistant to a disease than another related species or variety.
Selection of resistant plants as a control of plant diseases.
This is likely to have occurred not only because seeds from resistant and therefore healthier plants looked bigger and better than those from infected susceptible plants, but also because in severe disease out breaks, resistant plants were the only ones surviving and, therefore, their seeds were the only ones available for planting.
05 Introduction to Plant Pathology_0.pdftejendrakar76
Pathology is the study of disease and injury. It involves the examination of organs, tissues, and whole bodies to diagnose diseases. This field is divided into subdisciplines, with anatomical pathology being concerned with the diagnosis of disease based on the gross
Home Vegetables: Organic Controls for Insects
`
For more information, Please see websites below:
`
Organic Edible Schoolyards & Gardening with Children
http://scribd.com/doc/239851214
`
Double Food Production from your School Garden with Organic Tech
http://scribd.com/doc/239851079
`
Free School Gardening Art Posters
http://scribd.com/doc/239851159`
`
Increase Food Production with Companion Planting in your School Garden
http://scribd.com/doc/239851159
`
Healthy Foods Dramatically Improves Student Academic Success
http://scribd.com/doc/239851348
`
City Chickens for your Organic School Garden
http://scribd.com/doc/239850440
`
Simple Square Foot Gardening for Schools - Teacher Guide
http://scribd.com/doc/239851110
A detailed project on plant diseases,causes, symptoms and control measures with illustrations. The project explains in brief fungal and bacterial and and their control measures.Blast disease, citrus canker and leaf mosaic disease of tapioca are explained in detail. Non - infectious diseases are also mentioned.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
05 Introduction to Plant Pathology_0.pdftejendrakar76
Pathology is the study of disease and injury. It involves the examination of organs, tissues, and whole bodies to diagnose diseases. This field is divided into subdisciplines, with anatomical pathology being concerned with the diagnosis of disease based on the gross
Home Vegetables: Organic Controls for Insects
`
For more information, Please see websites below:
`
Organic Edible Schoolyards & Gardening with Children
http://scribd.com/doc/239851214
`
Double Food Production from your School Garden with Organic Tech
http://scribd.com/doc/239851079
`
Free School Gardening Art Posters
http://scribd.com/doc/239851159`
`
Increase Food Production with Companion Planting in your School Garden
http://scribd.com/doc/239851159
`
Healthy Foods Dramatically Improves Student Academic Success
http://scribd.com/doc/239851348
`
City Chickens for your Organic School Garden
http://scribd.com/doc/239850440
`
Simple Square Foot Gardening for Schools - Teacher Guide
http://scribd.com/doc/239851110
A detailed project on plant diseases,causes, symptoms and control measures with illustrations. The project explains in brief fungal and bacterial and and their control measures.Blast disease, citrus canker and leaf mosaic disease of tapioca are explained in detail. Non - infectious diseases are also mentioned.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
2. Plant pathology
deals with the nature, causes and control of
plant diseases. It is a science which looks into
the characteristics of the diseases, their causes,
plant-pathogen interactions, factors affecting
disease development in individual plants and in
populations, and various means of controlling
diseases.
is the scientific study of diseases in plants
caused by pathogens (infectious organisms) and
environmental conditions (physiological factors).
3. Plant pathology
• The art of plant pathology deals with the
application of the knowledge gained from
studying it as a science. This includes the
following:
a. diagnosis or recognizing particular diseases by
their symptoms and sign; diseases assessment
and forecasting;
b. recommendation of appropriate control
measures; and
c. field application of suitable of control measures
4. Plant pathology
The ultimate objective of plant pathology is to
prevent or minimize plant diseases not only
to increase food production but also to
maintain the quantity and quality of the
harvested fresh commodity until it reach the
final consumer. We also need to protect and
preserve plant used for fiber, drugs and
aesthetics.
5. ECONOMIC IMPORTANCE OF PLANT DISEASES
• It has been said that men and animals exist on
earth as guests of the plant kingdom because
only the green plant can convert the energy
from the sun into food. We depend on plants
not only for food but also for our clothing and
shelter needs and for numerous luxuries.
When diseases kill plant, all other form of life
on earth is adversely affected.
6. ECONOMIC IMPORTANCE OF PLANT
DISEASES
• The study of plant diseases is important as they cause
loss to the plant as well as plant produce. The various
types of losses occur in the field, in storage or any time
between sowing and consumption of produce. The
diseases are responsible for direct monitory loss and
material loss. Plant diseases still inflect suffering on
untold millions of people worldwide causing an
estimated annual yield loss of 14% globally with an
estimated economic loss of 220 billion U. S. dollars.
Fossil evidence indicates that plants were affected by
different diseases 250 million year ago. The Plant
disease has been associated with many important
events in the history of mankind of the earth
7. Diseases that had caused enormous economic
losses
The following are examples of plant diseases in the Philippines that have caused
enormous economic losses:
• Cadang-cadang disease of coconut
first observed in 1918; have caused the country a loss of over $200M.
• Downy mildew of corn
the nemesis of corn; loss can be as high 95% amounting to over P170M
annually; now controlled by chemical seed treatment using metalaxy, discovered in
1978; caused by the fungus Peronosclerospora philippinensis (weston) shaw.
• Rice tungro disease
affected 70,000 has in 1971; 1.22M cavans rough rice lost valued at
P30,357,000
• Coffee rust
destroyed the coffee industry in Batangas province.
• Citrus decline
destroyed citrus plantations in Batangas.
8. Types of Crop Losses
• Reduction in yield
-Leaf spots/blight reduce photosynthetic capacity of plants
-Root pathogens
-Fruit rots and fruit spots – reduce quantity of harvestable and marketable
fruits
• Losses from deterioration during storage, marketing or transport
-The amount of lost food daily is enough to feed the world’s population
• Reduction in quality of produce
-Citrus fruits with scabs
-Moldy cereals and other commodities
-Reduced strength and undesirable discoloration in wood pulp
-Poor germination of infected seeds Losses from produce contaminated with
toxins that cause various disorders and/or death to animals including man.
Aflatoxin
-Produced by Aspergillus flavus; carcinogenic to animals and man;
commonly found in stored corn, sorghum, copra, root crops etc.
9. Types of Crop Losses
Ochratoxin
-A mycotoxin produced by A. ochraceous causes cancer of the liver.
Yellow rice toxins
-Formed by Penicillium spp.; caused several deaths in Japan.
Estrogenic factor in corn
-Produced by Fusarium graminearum; causes testes of young male swine to
have atrophy and to have uterus of female pigs to enlarge and abort.
Fumonisins
-Formed by Fusaruim spp. In corn grains; caused esophageal cancer in man
and toxic to animals like horses. Losses due to predisposition of host to attack by other
pathogens
Example:
Nematode injuries on roots serve as point of entry to other pathogens.
Leaf pathogens weaken plants which can become a host susceptible to root-rotting
pathogens.
Severely defoliated trees can be readily attacked Armillaria mellea and other fungi.
10. Types of Crop Losses
• Losses from increased cost of production and handling
Cost of disease control is an added cost.
Cost of culling disease commodities for marketing and processing.
Infected and stained wood chips need longer time to bleach to
obtain white paper product.
• Vital Processes Affected
root absorption
uptake of water and minerals
photosynthesis
respiration
transport of photosynthates
reproduction
11. Importance of Plant Diseases
Plant diseases damage plants and plant products
therefore it is directly related to importance of
plant as:
• Food
• Shelter
• Clothing
• Medicine
• Aesthetics
• Improving environment
• Luxuries
12. Negative Impact of Plant Diseases
• Plant diseases endanger food supply
• Reduce the quantity and quality of plant produce
• Cause financial losses
• Limits the kind of plants and industries in an area
• Make plants poisonous to human
• Increase cost of production due to control
measures
13. CONCEPTS OF PLANT DISEASES
Disease – abnormal condition that negatively affects the
structure of function of all part of organism
- dis order of structures/functions of an organism
- is a common occurrence but a wholly satisfactory
definition of the term has eluded plant pathologists for so
long.
• Important Role of the Environment-
A favorable environment is critically important for
disease development – even the most susceptible
plants exposed to huge amounts of a pathogen will not
develop disease unless environmental conditions are
favourable.
15. FACTORS FOR SUCCESSFUL DISEASE
DEVELOPMENT
1. Properties of pathogen
• Level of virulence
• Adaptability
• Dispersal efficiency
• Survival efficiency
• Reproductive fitness
2. Properties of host
• Susceptibility
• Growth stage and form
• Population density and structure
• General health
3. Properties of environment
• Temperature
• Rainfall/dew
• Leaf wetness period
• Soil properties
• Wind
16. CAUSES OF PLANT DISEASES
• Plant Disease Agents
1. Living Organisms - includes fungi, bacteria,
viruses and nematodes
2. Non-living agents – including unbalanced soil
fertility, toxic chemicals, air pollution, frost,
drought, sunburn, wind and hail.
17. LIVING ORGANISMS - PLANT
PATHOGENS
1. Fungi-Fungi can cause a variety of symptoms including leaf
spots and blights, root rots, seedling blights, seed
discoloration, wilts, and stem rots
18. LIVING ORGANISMS - PLANT
PATHOGENS
2. Bacteria- Typical symptoms of bacterial diseases include leaf
spots, water soaking, and soft rots of plant tissues
19. LIVING ORGANISMS - PLANT
PATHOGENS
3. Viruses- Typical viral symptoms include mosaic patterns on
leaves, deformation of plant tissues, stunting, seed discoloration,
and reduced yield.
20. LIVING ORGANISMS - PLANT
PATHOGENS
4. Nematodes- Most important plant‐parasitic nematodes feed on plant roots
and directly interfere with water and nutrient uptake by the plant. Root injury
causes aboveground symptoms similar to those produced by other conditions
that damage root systems
21. DISEASE CYCLE
STAGES OF PLANT DISEASES
1. INOCULATION
-the arrival of pathogen on the host
-initial contact of a pathogen with a site of plant where infection is
possible
• Inoculum – any part of the pathogen that can initiate infection
Examples: Fungi – Spores, sclerotia or hyphae
Bacteria - Mollicutes, protozoa, viruses or viroids: whole individual
Nematodes: Adults, juveniles or eggs
Sources of inoculum
• Branches, trunks, roots of plant
• Plant debris, soil in the field
• Seeds, transplants, tubers, other propagative organs
• Sources outside the field (nearby plants or fields)
• Perennial weeds, alternate hosts
22. DISEASE CYCLE
2. PENETRATION -initial invasion of the host on the
pathogen
• Direct penetration through intact plant surfaces –
Fungi and Nematodes
• Penetration through natural openings – E.g.:
Stoma, hydathode (open pores at margins and
tips of leaves), nectarthode & lenticels (openings
on fruits, stems & tubers – Fungi & Bacteria
• Penetration through wounds – Fungi, bacteria,
mollicutes, viruses & viroids
23. DISEASE CYCLE
3. INFECTION – establishment of pathogen with
vulnerable cells or tissues of the host and obtain
the nutrients from them. Successful infection will
produce symptoms.
4. GROWTH AND REPRODUCTION
• colonization
• the pathogen will grow and multiply within the
infected host
• Successful colonization results in the appearance
of symptoms
24. DISEASE CYCLE
5. DISSEMINATION OF PATHOGEN – transport of spores
of infectious bodies from one host to another host at
various distance resulting in the spread of the disease
Pathogens are disseminated by several way:
• By air
• By water
• By insects, nematodes, and other vectors (during
feeding)
• By seed and transplanting process
• By human
25. Epidemiology
Epidemic
(Layman’s view) is a wide spread, explosive disease
outbreak.
Van der Plank (19630) – Epidemic is an increase in
disease incidence within the population with time.
Epiphytotics
Refer to epidemics of plant disease
Endemic
Disease is one that is native or indigenous to a
particular place.
26. Terminology
Pandemic disease
It is one of worldwide or widespread
occurrence throughout a cotenant or a region.
Sporadic disease
Occur at irregular intervals.
Exotic disease
it is one which had been introduced from
some other area.
27. Factors Affecting the Development of
Epidemics
1. Plant susceptibility
2. Pathogen virulence
3. The duration and intensity of the various
environmental factors
28. Variability in Plant Pathogens
Plant pathogen that causes plant diseases varies from fungi,
bacteria, virus, and others. And these pathogens can be further
classified according to taxonomy
Terminology
Physiological specialization – within the species of a pathogen
there exist certain individuals that are morphologically similar but
differs with respect to their physiology, biochemical characters and
pathogenicity and are differentiated on the basis of their reaction
on certain host genera or cultivars
Physiologic race – individuals within the species of a pathogen that
morphologically similar but differ with respect to their
pathogenicity on particular set of host varieties.
29. Variability in fungi
1. Mutation
2. Recombination
3.Heterokaryosis
4.Parasexualism - is the process by which
genetic recombination can occur within fungal
heterokaryon
5. Heteroploidy
30. Variability in Bacteria
1. Conjugation- Transfer of DNA from one
bacterial cell to another
2. Transformation- DNA taken up from external
environment by absorption
3. Transduction - Transfer of bacterial genes
with a bacteriophage
32. Variability - it is the property of an organism to change its
characters from one generation to the other. Variation -
when progeny of an individual show variation in
characters from parents such a progeny is called a variant.
Pathotype - A pathotype is a population of a parasite
species in which all individuals have a stated pathosystem
character (pathogenicity or parasitic ability) in common.
Biotype - progeny developed by variant having similar
heredity is called a biotype or a subgroup of individuals
within the species, usually characterized by the
possession of single or few characters in common.