This document discusses plant diseases, their importance, causes, and principles of disease control. It notes that plant diseases have impacted humanity throughout history, causing famines from crop losses of 30-50% in some areas. Environmental factors like temperature, humidity, soil properties, and nutrients can influence disease development. Control methods aim to exclude, eradicate, or protect against pathogens using practices like sanitation, crop rotation, and regulating the environment, along with developing host resistance. The key message is that prayer and respecting one's mother are more protective than any security.
This Presentation includes various tactics of IDM like Cultural control, Physical control, Chemical control, Biological control of plant disease. Useful for UG, PG Botany and Agriculture students
This Presentation includes various tactics of IDM like Cultural control, Physical control, Chemical control, Biological control of plant disease. Useful for UG, PG Botany and Agriculture students
This power-point provides general knowledge on the major wheat disease as
Common bunt of wheat
Fusarium head blight of wheat
Loose smut of wheat
Stagonospora nodorum blotch of wheat
Bacterial streak of wheat
Barley yellow dwarf virus of wheat
Leaf rust of wheat
Stem rust of wheat
Stripe rust of wheat
Powdery mildew of wheat
Septoria tritici blotch of wheat
Stagonospora nodorum blotch
Tan spot
Wheat soilborne mosaic
Wheat spindle streak mosaic
Wheat streak mosaic
Cephalosporium stripe
Common root rot
Fusarium root,
crown, and foot rots
Take-all of wheat
Manipulation of cultural practices at an appropriate time for reducing or avoiding disease damage to crops
The cultural practices make the environment less favorable for the plant pathogen and or more favorable for its bio control agents.
According to Stevens(1960) , the cultural methods of disease control involve agricultural cropping, harvesting and storage, tillage, crop rotation, soil management, growing of resistant varieties, planning of land use, and other related practices.
list of cultural practices
1.Soil solarization
2.Deep summer ploughing
3.Organic and inorganic amendments
4.Fallowing
5. Crop rotation
6. Green manure crops
7.Irrigation practices
and others Roughing
Strip farming
Trap and decay crops
Burning crop residue
Fertilizers usage
Time of sowing
Sanitation
This power-point provides general knowledge on the major wheat disease as
Common bunt of wheat
Fusarium head blight of wheat
Loose smut of wheat
Stagonospora nodorum blotch of wheat
Bacterial streak of wheat
Barley yellow dwarf virus of wheat
Leaf rust of wheat
Stem rust of wheat
Stripe rust of wheat
Powdery mildew of wheat
Septoria tritici blotch of wheat
Stagonospora nodorum blotch
Tan spot
Wheat soilborne mosaic
Wheat spindle streak mosaic
Wheat streak mosaic
Cephalosporium stripe
Common root rot
Fusarium root,
crown, and foot rots
Take-all of wheat
Manipulation of cultural practices at an appropriate time for reducing or avoiding disease damage to crops
The cultural practices make the environment less favorable for the plant pathogen and or more favorable for its bio control agents.
According to Stevens(1960) , the cultural methods of disease control involve agricultural cropping, harvesting and storage, tillage, crop rotation, soil management, growing of resistant varieties, planning of land use, and other related practices.
list of cultural practices
1.Soil solarization
2.Deep summer ploughing
3.Organic and inorganic amendments
4.Fallowing
5. Crop rotation
6. Green manure crops
7.Irrigation practices
and others Roughing
Strip farming
Trap and decay crops
Burning crop residue
Fertilizers usage
Time of sowing
Sanitation
MANAGEMENT OF SOIL BORNE PATHOGENS OF VEGETABLE CROPS UNDER PROTECTED CULTIVA...Mayur Thesiya
MANAGEMENT OF SOIL BORNE PATHOGENS OF VEGETABLE CROPS UNDER PROTECTED CULTIVATION
Soilborne pathogens and nematodes are very destructive in vegetables crops and one of the most limiting factors to farmers income. Soil fumigation has been an essential component of greenhouses crops since the 1960s. Growing vegetables without soil fumigants has remained a challenge, in part because commercially acceptable eggplant cultivars produced through conventional breeding lack resistance to many soil borne plant pathogens. Grafting cultivars with high quality and productivity on rootstocks that are resistant to soil pests and diseases is a method known for years ago, but which was improved and quickly spread in the last years. The objective of the researches was to evaluate the performance of the eggplant grafting on the some rootstocks in greenhouse conditions, alone and in combination with soil fumigation using metham sodium. Data obtained in the combinations scion/rootstock and not grafted eggplants were compared with data recorded where the metham sodium fumigant was used and as well as with the combinations grafted eggplants planted in soil disinfested with metham sodium. The marketable yield, fruits quality, frequency and root galling index of soilborne disease and nematodes, in the experimental variants were determined and calculated. Grafting process combined with the metham sodium soil disinfestation led to significant reduction in the incidence of attack produced by soilborne disease (Fusarium oxysporum f. sp. melongenae, Verticillium dahlia) and nematodes (Meloidogine incognita).
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.
The disease which develops on harvested parts of the plants like seeds, fruits and also in vegetables are called post-harvest disease. It leads to measurable qualitative and quantitative food loss along the supply chain, starting at the time of harvest till its
consumption or other end uses. In Nepal, different studies have shown the postharvest losses of fruits and vegetables are 20-50% (Gautam and Bhattarai, 2012) and 6-12% losses in worldwide.
This slide tries to address status of Postharvest diseases of different vegetables, fruits, cereals and legumes, their symptoms, losses and
integrated management .
The disease which develops on harvested parts of the plants like seeds, fruits and also in vegetables are called post-harvest disease. It leads to measurable qualitative and quantitative food loss along the supply chain, starting at the time of harvest till its consumption or other end uses. In Nepal, different studies have shown the postharvest losses of fruits and vegetables are 20-50% (Gautam and Bhattarai, 2012) and 6-12% losses in worldwide.
Food hygiene is more than cleanliness ......
Protecting food from risk of contamination, including harmful bacteria, poison and other foreign bodies.
Preventing any bacteria present multiplying to an extent which would result in the illness of consumers or the early spoilage of the food.
Destroying any harmful bacteria in the food by thorough cooking
or processing.
Discarding unfit or contaminated food.
T-Cell Activation
• Concept of immune response
• T cell-mediated immune response
• B cell-mediated immune response
I. Concept of immune response
• A collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules in the immune system.
II. T cell-mediated immune response
• Cell-mediated immunity is the arm of the adaptive immune response whose role is to combat infection of intracellular pathogens, such as intracellular bacteria (mycobacteria, listeria monocytogens), viruses, protozoa, etc.
Major Histocompatibility Complex
MHC:
• Major Histocompatibility Complex
– Cluster of genes found in all mammals
– Its products play role in discriminating self/non-self
– Participant in both humoral and cell-mediated immunity
• MHC Act As Antigen Presenting Structures
• In Human MHC Is Found On Chromosome 6
– Referred to as HLA complex
• In Mice MHC Is Found On Chromosome 17
– Referred to as H-2 complex
• Genes Of MHC Organized In 3 Classes
– Class I MHC genes
• Glycoproteins expressed on all nucleated cells
• Major function to present processed Ags to TC
– Class II MHC genes
• Glycoproteins expressed on macrophages, B-cells, DCs
• Major function to present processed Ags to TH
– Class III MHC genes
• Products that include secreted proteins that have immune functions. Ex. Complement system, inflammatory molecules
Antigen Processing and Presentation MID
Antigens and “foreignness”
• Antigens (or, more properly, immunogens) have a series of features which confer immunogenicity.
• One of these features is “foreignness.”
• So, we can infer that – most often – antigens – ultimately – originate externally.
• (There are exceptions, of course. Some cells become transformed by disease [e. g., cancer] or by aging. In such instances, the antigens have an internal origin.)
Extinction of a particular animal or plant species occurs when there are no more individuals of that species alive anywhere in the world - the species has died out. This is a natural part of evolution. But sometimes extinctions happen at a much faster rate than usual. Natural Causes of Extinction.
Difference between In-Situ and Ex-Situ conservation
Conservation of biodiversity and genetic resources helps protect, maintain and recover endangered animal and plant species. There are mainly two strategies for the conservation of wildlife: In-situ conservation and Ex-situ conservation. Although, both the strategies aim to maintain and recover endangered species, they are different from each other. Let us see how they differ from each other!
Evolution Of Bacteria
Bacteria have existed from very early in the history of life on Earth. Bacteria fossils discovered in rocks date from at least the Devonian Period (419.2 million to 358.9 million years ago), and there are convincing arguments that bacteria have been present since early Precambrian time, about 3.5 billion years ago. Bacteria were widespread on Earth at least since the latter part of the Paleoproterozoic, roughly 1.8 billion years ago, when oxygen appeared in the atmosphere as a result of the action of the cyanobacteria. Bacteria have thus had plenty of time to adapt to their environments and to have given rise to numerous descendant forms.
Impact of Environment on Loss of Genetic Diversity and Speciation
Genetic variation describes naturally occurring genetic differences among individuals of the same species. This variation permits flexibility and survival of a population in the face of changing environmental circumstances. Consequently, genetic variation is often considered an advantage, as it is a form of preparation for the unexpected. But how does genetic variation increase or decrease? And what effect do fluctuations in genetic variation have on populations over time?
GENE ENVIRONMENT INTERACTION
Subtle differences in one person’s genes can cause them to respond differently to the same environmental exposure as another person. As a result, some people may develop a disease after being exposed to something in the environment while others may not.
As scientists learn more about the connection between genes and the environment, they pursue new approaches for preventing and treating disease that consider individual genetic codes.
How to store food in hot
The Good News
To maximize benefit of preservation, keep your food as fresh as possible for as long as possible. You can do this, even in the heat, by creating a “cooler” made from two basic terra cotta pots, one larger than the other. Put the smaller pot in the larger one, fill the gap with sand, and saturate the sand with water. Then cover it with a cloth. To add additional insulation from the heat, bury the pot up to its rim. The evaporation of moisture from the wet sand will cool the air around the food and help keep it fresh.
What is IUPAC naming?
In order to give compounds a name, certain rules must be followed. When naming organic compounds, the IUPAC (International Union of Pure and Applied Chemistry) nomenclature (naming scheme) is used. This is to give consistency to the names. It also enables every compound to have a unique name, which is not possible with the common names used (for example in industry). We will first look at some of the steps that need to be followed when naming a compound, and then try to apply these rules to some specific examples.
IUPAC Nomenclature
IUPAC nomenclature uses the longest continuous chain of carbon atoms to determine the basic root name of the compound. The root name is then modified due to the presence of different functional groups which replace hydrogen or carbon atoms in the parent structure.
Hybridization describes the bonding atoms from an atom's point of view. For a tetrahedral coordinated carbon (e.g. methane CH4), the carbon should have 4 orbitals with the correct symmetry to bond to the 4 hydrogen atoms.
INTRODUCTION:
Hybrid Orbitals
Developed by Linus Pauling, the concept of hybrid orbitals was a theory created to explain the structures of molecules in space. The theory consists of combining atomic orbitals (ex: s,p,d,f) into new hybrid orbitals (ex: sp, sp2, sp3).
1. Why Firefly give light during night?
2. Why atomic mass and Atomic numbers are given to elements ?
3. Why elements have been characterized and classified into different groups?
4. What is the transition of elements and what they play their role in elements stability?
Diabetes is a rapidly and serious health problem in Pakistan. This chronic condition is associated with serious long-term complications, including higher risk of heart disease and stroke. Aggressive treatment of hypertension and hyperlipideamia can result in a substantial reduction in cardiovascular events in patients with diabetes 1. Consequently pharmacist-led diabetes cardiovascular risk (DCVR) clinics have been established in both primary and secondary care sites in NHS Lothian during the past five years. An audit of the pharmaceutical care delivery at the clinics was conducted in order to evaluate practice and to standardize the pharmacists’ documentation of outcomes. Pharmaceutical care issues (PCI) and patient details were collected both prospectively and retrospectively from three DCVR clinics. The PCI`s were categorized according to a triangularised system consisting of multiple categories. These were ‘checks’, ‘changes’ (‘change in drug therapy process’ and ‘change in drug therapy’), ‘drug therapy problems’ and ‘quality assurance descriptors’ (‘timer perspective’ and ‘degree of change’). A verified medication assessment tool (MAT) for patients with chronic cardiovascular disease was applied to the patients from one of the clinics. The tool was used to quantify PCI`s and pharmacist actions that were centered on implementing or enforcing clinical guideline standards. A database was developed to be used as an assessment tool and to standardize the documentation of achievement of outcomes. Feedback on the audit of the pharmaceutical care delivery and the database was received from the DCVR clinic pharmacist at a focus group meeting.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
Micro RNA genes and their likely influence in rice (Oryza sativa L.) dynamic ...Open Access Research Paper
Micro RNAs (miRNAs) are small non-coding RNAs molecules having approximately 18-25 nucleotides, they are present in both plants and animals genomes. MiRNAs have diverse spatial expression patterns and regulate various developmental metabolisms, stress responses and other physiological processes. The dynamic gene expression playing major roles in phenotypic differences in organisms are believed to be controlled by miRNAs. Mutations in regions of regulatory factors, such as miRNA genes or transcription factors (TF) necessitated by dynamic environmental factors or pathogen infections, have tremendous effects on structure and expression of genes. The resultant novel gene products presents potential explanations for constant evolving desirable traits that have long been bred using conventional means, biotechnology or genetic engineering. Rice grain quality, yield, disease tolerance, climate-resilience and palatability properties are not exceptional to miRN Asmutations effects. There are new insights courtesy of high-throughput sequencing and improved proteomic techniques that organisms’ complexity and adaptations are highly contributed by miRNAs containing regulatory networks. This article aims to expound on how rice miRNAs could be driving evolution of traits and highlight the latest miRNA research progress. Moreover, the review accentuates miRNAs grey areas to be addressed and gives recommendations for further studies.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
Natural farming @ Dr. Siddhartha S. Jena.pptxsidjena70
A brief about organic farming/ Natural farming/ Zero budget natural farming/ Subash Palekar Natural farming which keeps us and environment safe and healthy. Next gen Agricultural practices of chemical free farming.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
Characterization and the Kinetics of drying at the drying oven and with micro...
Plant disease and its importance
1. 1
Amjad Khan Afridi
Plant Disease And Its Importance
Plant disease, an impairment of the normal state of a plant that interrupts or modifies its
vital functions.
Plant diseases are known from times preceding the earliest writings.
Plant disease outbreaks with similar far-reaching effects in more recent times include
Late blight of potato in Ireland (1845–60)
Powdery and downy mildew of grape - France (1851 and 1878)
coffee rust - Ceylon (starting in the 1870s);
Sigatoka leaf spot and panama disease of banana - central America (1900–65)
Black stem rust of wheat - (1916, 1935, 1953–54)
Loss of crops from plant diseases may result in hunger and starvation, especially in less
developed countries where access to disease-control methods is limited and annual losses of 30
to 50 percent are common for major crops. In some years, losses are much greater, producing
catastrophic results for those who depend on the crop for food.
Major disease outbreaks among food crops have led to famines and mass migrations throughout
history. The devastating outbreak of late blight of potato (Phytophthora infestans) that began in
Europe in 1845 and brought about the Irish famine caused starvation, death, and mass migration
of the Irish population.
Diseases — a normal part of nature:
Plant diseases are a normal part of nature and one of many ecological factors that help
keep the hundreds of thousands of living plants and animals in balance with one another.
Plant cells contain special signaling pathways that enhance their defenses against insects,
animals, and pathogens.
One such example involves a plant hormone called jasmonate (jasmonic acid).
In the absence of harmful stimuli, jasmonate binds to special proteins, called JAZ proteins, to
regulate plant growth, Pollen production, and other. it also increase the defense mechanism of
plants.
Disease development and transmission
Pathogenesis and saprogenesis
2. 2
Amjad Khan Afridi
Pathogenesis is the stage of disease in which the pathogen is in intimate association with
living host tissue.
Three fairly distinct stages are involved:
Inoculation: transfer of the pathogen to the infection court, or area in which invasion of
the plant occurs (the infection court may be the unbroken plant surface, a variety of wounds, or
natural openings.
Incubation: the period of time between the arrival of the pathogen in the infection court
and the appearance of symptoms
Infection: the appearance of disease symptoms accompanied by the establishment and
spread of the pathogen.
Environmental factors affectingdisease development
Temperature:
Each pathogen has an optimum temperature for growth. In addition, different growth
stages of the fungus, such as the production of spores, their germination, and the growth of the
mycelium, may have slightly different optimum temperatures.
Relative humidity :
Relative humidity is very critical in fungal spore germination and the development of
storage rots. High humidity favours development of the great majority of leaf and fruit diseases
caused by fungi and bacteria. Moisture is generally needed for fungal spore germination, the
multiplication and penetration of bacteria, and the initiation of infection.
Soil moisture:
High or low soil moisture may be a limiting factor in the development of certain root rot
diseases. High soil-moisture levels favour development of destructive water mold fungi, such as
species of Aphanomyces, Pythium, and Phytophthora.
Soil pH
Soil pH, a measure of acidity or alkalinity, markedly influences a few diseases, such as
common scab of potato and club root of crucifers (Plasmodiophora brassicae).
Growth of the potato scab organism is suppressed at a pH of 5.2 or slightly below (pH 7
is neutral; numbers below 7 indicate acidity, and those above 7 indicate alkalinity). Scab is not
normally a problem when the natural soil pH is about 5.2.
3. 3
Amjad Khan Afridi
Soil type
Certain pathogens are favoured by loam soils and others by clay soils. Phymatotrichum root
rot attacks cotton and some 2,000 other plants Phymatotrichum fungus is serious only in black
alkaline soils—pH 7.3 or above—that are low in organic matter.
Soil fertility:
Greenhouse and field experiments have shown that raising or lowering the levels of
certain nutrient elements required by plants frequently influences the development of some
infectious diseases.
Disease Symptoms
Plant disease
symptoms
Description and causes Examples
Water-soaking A water-soaked, translucent condition of
tissues caused by water moving from host
cells into intercellular spaces
late blight lesions on potato and tomato
leaves; bacterial soft rot of fleshy
vegetables
Wilting Temporary or permanent drooping of leaves,
shoots, or entire plants from lack of water
bacterial wilt of cucumber; Fusarium
wilt of tomato
Abnormal coloration Yellowing, reddening, bronzing, or purpling
in localized areas of leaves where
chlorophyll has been destroyed; may be due
to a variety of causes
cabbage and aster yellows; halo blight of
beans; potassium or phosphorus
deficiency
Necrotic Localized or general death of cells or
disintegration of tissues
Leaf spot
Blast Sudden blighting or death of young buds,
flowers, or young fruit; failure to produce
fruit or seeds
Botrytis blight of peony buds; oat blast
Blight Sudden or total discoloration and killing of
large numbers of blossoms, leaves, shoots, or
limbs or the entire plant; usually young
tissues are attacked; the disease name is
often coupled with the name of the host and
the part attacked—blossom blight, twig
blight, tip blight
Leaf blight
Canker A definite, dead, often sunken or swollen and Nectria canker of hardwoods
4. 4
Amjad Khan Afridi
cracked area on a stem, limb, trunk, tuber, or
root surrounded by living tissues
Damping-off Decay of seed in soil, rapid death of
germinating seedlings before emergence, or
emerged seedlings suddenly wilting, toppling
over, and dying from rot at or near the soil
line
Nursery
Dieback Progressive browning and death of shoots,
branches, and roots starting at the tips
Diebacks in rose
Firing Drying and dying of leaves
Fleck A small, white to translucent spot or lesion
visible through a leaf
ozone injury
Mummification Final stage in certain fruit rots, in which the
dried, shriveled, and wrinkled fruit is called a
"mummy"
Downy mildew in grapes
Net necrosis An irregular crisscrossing of dark brown to
black lines giving a netted appearance
in potato tubers of plants with virus leaf
roll
Pitting Small dead areas within fleshy or woody
tissue that appears healthy externally;
definite sunken grooves or pits are formed
virus stem-pitting in apple
Rot Decomposition and putrefaction of cells,
later of tissues and organs; the rot may be
dry, firm, watery, or mushy and is
characterized by such names as hard rot, soft
rot, dry rot, black rot, and white rot
bacterial soft rot; berry rot; bud rot; bulb
rot
Scald Blanching of young fruit, foliage, and shoot
tissue; generally superficial
sunscald; apple and pear scald
Scorch Sudden death and "burning" of large,
indefinite areas in leaves and fruit
toxicity from pesticides and air
pollutants; drought; wind; lack or excess
of some nutrient
Spot A definite, localized, round to regular lesion,
often with a border of a different colour,
characterized as to location (leaf spot, fruit
spot) and colour (brown spot, black spot); if
numerous or if spots enlarge and merge, a
gray leaf spot of tomato; black spot of
rose; tar spot of maple
5. 5
Amjad Khan Afridi
large irregular blotch or blight may develop
Principles of disease control
Exclusion and avoidance
The principle of exclusion and avoidance is to keep the pathogen away from
the growing host plant. This practice commonly excludes pathogens by disinfection of plants,
seeds, or other parts, using chemicals or heat. Inspection and certification of seed and other
planting stock help ensure freedom from disease.
Plant disease and its importance
Eradication
Eradication is concerned with elimination of the disease agent after it has become
established in the area of the growing host or has penetrated the host. Such measures include
crop rotation, destruction of the diseased plants, elimination of alternate host plants, pruning,
disinfection, and heat treatments.
Protection
The principle of protection involves placing a barrier between the pathogen and the
susceptible part of the host to shield the host from the pathogen. This can be accomplished by
regulation of the environment, cultural and handling practices, control of insect carriers, and
application of chemical pesticides.
Regulation of the environment
Selection of outdoor growing areas where weather is unfavourable for disease is a method of
controlling disease by regulating the environment.
Cultural practices
Selection of the best time and depth of seeding and planting is an effective cultural practice
that reduces disease impact. Adjustment of soil moisture is another cultural practice of wider
spread usefulness. Adjustment of soil pH also leads to control of some diseases.
Regulation of fertility level and nutrient balance:
Potash and nitrogen, and the balance between the two, may affect the incidence of certain
bacterial, fungal, and viral diseases of corn, cotton, tobacco, and sugar beet. Adjusting the soil
6. 6
Amjad Khan Afridi
pH, adding chelated or soluble salts to the soil, or spraying the foliage with these or similar salts
is a corrective measure.
Control of insect vectors
There are many examples in which losses by bacteria, viruses, and mycoplasma-like disease
agents can be reduced by controlling aphids, leafhoppers, thrips, beetles, and other carriers of
these agents.
Biological control:
Biological control of plant diseases involves the use of micro organisms other than humans
to reduce or prevent infection by a pathogen. These organisms are called antagonists; they may
occur naturally within the host’s environment, or they may be purposefully applied to those parts
of the potential host plant where they can act directly or indirectly on the pathogen.
To sum up
The crop loss due to diseases is estimated to be approximately 30-50%. Cultivated plants are
often more susceptible to diseases than are their wild relatives. Important environmental factors
that may affect development of plant diseases are temperature, relative humidity, soil moisture,
soil pH, soil type, and soil fertility. Each pathogen has an optimum temperature for growth .
High soil-moisture levels favour development of destructive water mold fungi, such as species of
Aphanomyces, Pythium, and Phytophthora. High humidity favours development of the great
majority of leaf and fruit diseases caused by fungi and bacteria. Soil pH, a measure of acidity or
alkalinity, markedly influences a few diseases, such as common scab of potato and clubroot
(Plasmodiophora brassicae) of crucifers. Raising or lowering the levels of certain nutrients also
influences the development of some infectious diseases.
Most control measures are directed against inoculums of the pathogen and involve the principles
of exclusion and avoidance, eradication, protection, host resistance and selection, and therapy.
Thousands of securities can not protect you,but There is only the Prayers of your Mother
protect you.
Do not hurt your Mother with your words, Because she learnt you how to speak