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 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
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.
SURVIVAL AND DISPERSAL OF PHYTOPATHOGENIC BACTERIA.pdfOm Prakash
SURVIVAL OF PHYTOPATHOGENIC BACTERIA
Phytopathogenic bacteria have the ability to survive both for longer & shorter periods including soil, seed, diseased crop debris, weed host, and insect vectors.
DISPERSAL OF PLANT PATHOGENIC BACTERIA
To make a healthy plant diseased, the first requirement of a pathogen is to spread its inoculum (primary as well as secondary) from the source of survival to the susceptible parts of a healthy plant. The spread of a plant pathogen within the general area in which it is already established is called “dispersal” or “dissemination”.
Moving the inoculum only a few inches and transporting it for hundreds of miles both constitute its dispersal or dissemination. However, pathogen dispersal is not necessary only for the spread of diseases but also for the continuity of the life-cycle and evolution of the pathogen. Detailed knowledge of pathogen-dispersal is essential to find out effective control measures for diseases because the possibilities of preventing dispersal and thereby breaking the infection chain always exist.
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.
SURVIVAL AND DISPERSAL OF PHYTOPATHOGENIC BACTERIA.pdfOm Prakash
SURVIVAL OF PHYTOPATHOGENIC BACTERIA
Phytopathogenic bacteria have the ability to survive both for longer & shorter periods including soil, seed, diseased crop debris, weed host, and insect vectors.
DISPERSAL OF PLANT PATHOGENIC BACTERIA
To make a healthy plant diseased, the first requirement of a pathogen is to spread its inoculum (primary as well as secondary) from the source of survival to the susceptible parts of a healthy plant. The spread of a plant pathogen within the general area in which it is already established is called “dispersal” or “dissemination”.
Moving the inoculum only a few inches and transporting it for hundreds of miles both constitute its dispersal or dissemination. However, pathogen dispersal is not necessary only for the spread of diseases but also for the continuity of the life-cycle and evolution of the pathogen. Detailed knowledge of pathogen-dispersal is essential to find out effective control measures for diseases because the possibilities of preventing dispersal and thereby breaking the infection chain always exist.
Environment is the factors surrounding plants from heat - Humidity - light - soil ...., and these factors may help the spread of the disease and the incidence and severity of the disease if it is suitable for the growth and reproduction of pathogens or work to increase the resistance to diseases and the disease does not occur if it is suitable for the growth of host plants .Plant disease is only an interaction between the three pillars of the disease triangle
(host plant - pathogen - environmental conditions).
This includes detailed explanation with examples on diseases, disease cycle, its importance to study, types of disease cycle and pathogenesis including its components, like, means of survival, dispersal of the plant pathogens, inoculation, type of inoculum, pre-penetration, penetration including different means of entry of pathogens, post-penetration activities of the pathogens inside the plant host and its exit from the host.
Thirty soil borne viruses or virus like agents are transmitted by five species of fungal vectors i.e soil inhibiting fungi or protists.
Known vectors are from members of class Plamodiophoromycetes in the division Myxomycota & class Chytridiomycetes in the division Eumycota.
CHAPTER 15Smith, T. M., & Smith, R. L. (2015). Elements of Ecolo.docxcravennichole326
CHAPTER 15
Smith, T. M., & Smith, R. L. (2015). Elements of Ecology (9th ed.). Boston, MA: Pearson.
15.1 Parasites Draw Resources from Host Organisms
Parasitism is a type of symbiotic relationship between organisms of different species. One species—the parasite—benefits from a prolonged, close association with the other species—the host—which is harmed. Parasites increase their fitness by exploiting host organisms for food, habitat, and dispersal. Although they draw nourishment from the tissues of the host organism, parasites typically do not kill their hosts as predators do. However, the host may die from secondary infection or suffer reduced fitness as a result of stunted growth, emaciation, modification of behavior, or sterility. In general, parasites are much smaller than their hosts, are highly specialized for their mode of life, and reproduce more quickly and in greater numbers than their hosts.
The definition of parasitism just presented may appear unambiguous. But as with predation the term parasitism is often used in a more general sense to describe a much broader range of interactions (see Section 14.1). Interactions between species frequently satisfy some, but not all, parts of this definition because in many cases it is hard to demonstrate that the host is harmed. In other cases, there may be no apparent specialization by the parasite or the interaction between the organisms may be short-lived. For example, because of the episodic nature of their feeding habits, mosquitoes and hematophagic (blood-feeding) bats are typically not considered parasitic. Parasitism can also be used to describe a form of feeding in which one animal appropriates food gathered by another (the host), which is a behavior termed cleptoparasitism (literally meaning “parasitism by theft”). An example is the brood parasitism practiced by many species of cuckoo (Cuculidae). Many cuckoos use other bird species as “babysitters”; they deposit their eggs in the nest of the host species, which raise the cuckoo young as one of their own (see Chapter 12 opening photograph). In the following discussion, we use the narrower definition of parasite as given in the previous paragraph, which includes a wide range of organisms—viruses, bacteria, protists, fungi, plants, and an array of invertebrates, among them arthropods. A heavy load of parasites is termed an infection, and the outcome of an infection is a disease.
Parasites are distinguished by size. Ecologically, parasites may be classified as microparasites and macroparasites. Microparasites include viruses, bacteria, and protists. They are characterized by small size and a short generation time. They develop and multiply rapidly within the host and are the class of parasites that we typically associate with the term disease. The infection generally lasts a short time relative to the host’s expected life span. Transmission from host to host is most often direct, although other species may serve as carriers.
Macroparasite ...
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
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Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
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How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Survival and dispersal of important plant pathogen
1. SURVIVAL AND DISPERSAL OF IMPORTANT
PLANT PATHOGENS
Department of Plant Pathology
Bihar agricultural university
Sabour , Bhagalpur (813210)
SUBMITED BY
RAM NIWAS
Registration no.-
BAC/M/PPLPATH/00
8/2017-18
SUBMITTED TO
Dr. Amarendra Kumar
Dr.Gireesh Chand
Dr .A.Anwer
Dr.S.N.Raghavan
Dr.A.Ghattak
2. INTRODUCTION
In the absence of their cultivated host, the pathogens
must be find some alternates source of their survival
to maintain the infection chain.
The means of survival are the first link in the
infection chain or the disease cycle. The initial
infection that occurs from these sources in the crop
are called primary infection and the propagules are
called primary inoculum.
After initiation of the disease in the crop, the spores
or cells or other structures of the pathogen are
sources of secondary inoculums and cause secondary
infection. The primary infection initiate the disease
and secondary infection spread the disease.
3.
4. SURVIVAL OF PLANT PATHOGENS
1.Infected host as
reservoir of primary
inoculum
2.Saprophytic
survival of fungal
pathogens
3.Dormant organs
of fungal pathogens
as source of survival
and primary
inoculum
SURVIVAL OF FUNGAL
PATHOGEN
5. 1.
(a)CULTIVATED
HOST
Eg. Mostly
pathogens of
fruit trees,
plasmopara,
pyricularia,
drechslera,
erysiphe etc.
(b)COLLATERAL
HOST
Eg. Yellow rust
pathogen in
wheat, bromus
spp. And
agropyron.
(c)ALTERNATES
HOST
Eg. Stem rust-
barberis and
thalictrum-leaf
rust.
INFECTED HOST AS
RESERVOIR OF PRIMARY
INOCULUM
6. In the absence of the living host ,the facultative parasites
are capable of surviving as saprophytes. Soil and plant
debris serve as media for this saprophytic survival. Spp.
Of Pythium, Sclerotium etc. resting structure like oospores
and sclerotia .In Pythium aphanidermatum( foot rot of
papaya), the fungus rapidly forming oospores. S. rolfsii,
Sclerotia are formed and these can germinate under
decaying residues.
P. aphanidermatum Sclerotia
7. DORMANT ORGANS OF FUNGAL PATHOGENS AS SOURCE OF SURVIVAL AND PRIMARY
INOCULUM
(1)Soil borne fungi:-a.dormant
spores(conidia,chlamydospores,oospores,perithesia etc.)
b.other dormant structure such as thickened hyphae and
sclerotia.
(2)Seed borne fungi:-a.dormant
spores on seed coat
b.dormant mycelium and spores
under the seed coat or in the
embryo.
8. (3)Dormant fungal structures including dead plant
parts remaining on the trees.
P. brassicae survive through its resting spores lying free
or in crop debris in the soil for upto 10 years. S.
subterranea survive through spores balls.Pythium
,Phytophthora and albugo are produced dormant
structure oospores and conidia
Plasmodiophora plant debries Phytophthora on dead plant
9. SURVIVAL OF
PHYTOPATHOGENIC
BACTERIA
2.IN PLANT
RESIDUE Eg.
Xanthomona
s,
Ralstonia,Pse
udomonas
etc.
3.IN SOIL
Transient visitors and
resident visitors
Eg. Erwinia,Clavibacter.
ralstonia.serratia etc.
Agrobacterium,Streptomys
es etc.
4. WITH INSECT
Eg.
E.trachiphila –
D.undecimpunt
ata
1.IN SEED
Eg.Xanthomon
as,clavibacter,
pseudomonas
etc
No resting spores
or simillar
structures except
in such genera as
bacillus and
clostridium which
form resting
endospores or in
S. scabies which
form conidia
10. Dormant structure(eggs,cysts,galls,cockles etc.).
Quiescence is an adaption for survival of nematodes
under adverse conditions. A. tritici are viable for upto 28
years in cockles, G.rostochiensis viable 7-8 years in absence
of the host.
CYST
S
GALLS
12. DISPERSAL OF PLANT
PATHOGEN
Transport of spores or infectious bodies, acting as
inoculum, from one host to another host at various
distances resulting in the spread of the disease.
OR
Displacement of a plant pathogen from its
place of production or origin to a suitable
place where it can grow/establish.
13. SPORE LIBERATION(TAKE OFF)
Squirt gun mechanism:-Ascus swells at
maturity and brust at the tip in air.
Rounding off mechanism:- Top of
sporophore rounded off and ejected into air.
Mechanical momentum:-Through rain drop
and winds.
Blowing away:-Rust uredospore.
Spash:-Pycnidia.
14. SPORE LANDING(DEPOSITION)
Sedimentation:-Under the influence of gravity.
Impaction:-wind flowing.
Rain deposition.
Dispersal of plant pathogen are mainly consist of two
method viz. active and passive dispersal.
Active dispersal:- No need any type of external
energy for dispersal of plant pathogen.
By soil:-Pythium and phytophthora form zoospores
can swim with water in the soil, Actinomycetes,
Synchytrium and Fusarium can also grow in the soil.
15. By seed:-Cuscuta, sclerotia of ergot fungi,
ear cockle and cyst containing nematode.
Pathogen present in seed coat such as smut
of bajra, karnal bunt of wheat, bunt of rice
and leaf smut of rice ,BLB etc.
Pstv are transmit by pollen.
By plant organ:- Mostly in vegetative
propagated plant such as black wart potato,
late blight of potato, citrus canker etc.
16. Passive dispersal:-This type of dispersal are
done by the help of any type of external energy
such as animals, insects, and nematode etc.
Animals:-Through vegetative propagation such
as late blight of potato, bacterial wilt of banana,
sigatoka disease of banana etc.
Insects:- Cucurbit wilt(E. Trachiephila-spoted
cucumber beetle-Diabrotica undecimpunctata),
dutch elm disease-Ceratostomella ulmi etc.
Nematode:-Yellow ear rot of wheat-
Rathayibacter tritici, grape fan leaf-xiphinema,
nepo-longidorus, tobra-trichodorus etc.
17. Surface running water
after heavy rains
Long distance ------ floods
Ex: The mycelial fragments, spores or sclerotia of
fungi,Colletotrichum , Fusarium, Macrophomina,Pythium,
Phytophthora, Sclerotium, etc.,
DISPERSAL BY WIND
Short distance dissemination
sporangia of downy mildew fungi, conidia of
powdery mildew fungi and basidiospores of rust
fungi
Long distance dessimination
Uredospores of rust fungi, Chlamydospores of
smut fungi conidia of Alternaria, Helminthosporium
and Pyricularia, etc.