Introduction to pathology by muhammad asif

PLANT PATHOLOGYPLANT PATHOLOGYINTRODUCTIONINTRODUCTION

By Muhammad AsifBy Muhammad Asif

INTRODUCTIONINTRODUCTION

Plants make up the majority of earths Plants make up the majority of earths living environmentliving environment

Plants are the only organisms that convert Plants are the only organisms that convert the suns energy to foodthe suns energy to food

All animals including humans depend on All animals including humans depend on plants for foodplants for food

Plants as do people get “sick”Plants as do people get “sick”

The causal agents are similar to humanThe causal agents are similar to human


Disease causing organisms include;Disease causing organisms include;

VirusesViruses

BacteriaBacteria

FungiFungi

ProtozoaProtozoa

NematodesNematodes

Or unfavorable environmental conditionsOr unfavorable environmental conditions


Plant pathology is the study of Plant pathology is the study of microorganisms and environmental factors microorganisms and environmental factors that cause plant diseasethat cause plant diseaseThe way they workThe way they workThe way they are avoided or controlledThe way they are avoided or controlledThe cost of control must be less than the The cost of control must be less than the profitprofit

Environment friendly materials must be Environment friendly materials must be usedused


A plant is considered healthy if it functions A plant is considered healthy if it functions to the best of its genetic abilityto the best of its genetic ability

When a plant function is interfered with by When a plant function is interfered with by a microorganism or environmental factor a microorganism or environmental factor the plant is diseasedthe plant is diseased

The visible changes are the symptomsThe visible changes are the symptoms

Some pathogens affect only one variety of Some pathogens affect only one variety of plant while others affect many speciesplant while others affect many species

History of Plant DiseaseHistory of Plant Disease

The Romans were so aware of famine The Romans were so aware of famine they created a special rust god, Robigo they created a special rust god, Robigo who was responsible to protect people who was responsible to protect people from faminefrom famine

These beliefs lasted about 2000 yearsThese beliefs lasted about 2000 years

The compound microscope was invented The compound microscope was invented in the 1600’sin the 1600’s

CLASSIFICATION OF CLASSIFICATION OF DISEASESDISEASES

Infectious diseaseInfectious disease Diseases caused by fungiDiseases caused by fungi Diseases caused by prokaryotes (bacteria & Diseases caused by prokaryotes (bacteria &

mollicutesmollicutes Diseases caused by parasitic plantsDiseases caused by parasitic plants Diseases caused by viruses and viroidsDiseases caused by viruses and viroids Diseases caused by nematodesDiseases caused by nematodes Diseases caused by protozoaDiseases caused by protozoa

Non Infectious diseasesNon Infectious diseases

Diseases caused by low or high temperatureDiseases caused by low or high temperature

Diseases caused by lack or excess soil HDiseases caused by lack or excess soil H22OO

Diseases caused by lack or excess lightDiseases caused by lack or excess light

Diseases caused by lack of oxygenDiseases caused by lack of oxygen

Diseases caused by air pollutionDiseases caused by air pollution

Diseases caused by nutrient deficienciesDiseases caused by nutrient deficiencies

Diseases caused by mineral toxicitiesDiseases caused by mineral toxicities

Non infectious plant diseasesNon infectious plant diseases

Diseases caused by soil acidity or Diseases caused by soil acidity or alkalinityalkalinity

Diseases caused by toxicity of pesticidesDiseases caused by toxicity of pesticides

Diseases caused by improper cultural Diseases caused by improper cultural practicespractices

The Birth of Plant PathologyThe Birth of Plant Pathology

The fungus found on potatoes was first The fungus found on potatoes was first described by Dr. C Montagne, a French described by Dr. C Montagne, a French doctor with Napoleon’s armydoctor with Napoleon’s armyHe shared his observation with Rev. M. J. He shared his observation with Rev. M. J. Berkely who thought it might be connected Berkely who thought it might be connected with the diseasewith the diseaseDr. John Lindley, a rival did not believe Dr. John Lindley, a rival did not believe there was a connectionthere was a connection


Was the fungi the cause or the effect?Was the fungi the cause or the effect?Grain was used as an export to raise $Grain was used as an export to raise $Sir Robert Peel used the blight as an Sir Robert Peel used the blight as an excuse to repeal the protectionist trade excuse to repeal the protectionist trade laws to import corn from America to feed laws to import corn from America to feed the starving Irish. It was called Peel’s the starving Irish. It was called Peel’s Brimestone” because the recipients were Brimestone” because the recipients were considered ungratefulconsidered ungrateful


During a 15 year period 1 million Irish died of During a 15 year period 1 million Irish died of disease and starvation and another 1.5 million disease and starvation and another 1.5 million left to go to the U.S. or Canadaleft to go to the U.S. or Canada

The scientist of the time were unable to save the The scientist of the time were unable to save the crops but there came an understanding of plant crops but there came an understanding of plant diseasedisease

Anton deBary, a German Botanist performed Anton deBary, a German Botanist performed experiments that proved the role of fungus in the experiments that proved the role of fungus in the blightblight


For 200 years people thought the disease For 200 years people thought the disease causing organisms were the result , not the causing organisms were the result , not the causecause

The theory of spontaneous generation was The theory of spontaneous generation was abandoned for the germ theory in 1863abandoned for the germ theory in 1863

It was originally named It was originally named Botrytis infestansBotrytis infestans by by Montagne but was changed to Montagne but was changed to Phytophthora Phytophthora infestansinfestans by deBary because he realized they by deBary because he realized they were not relatedwere not related


Phyto= plantPhyto= plant

Phthora =destroyerPhthora =destroyer

Phytophthora= plant destroyerPhytophthora= plant destroyer

Infestans=devastating infestationInfestans=devastating infestation

Usual microorganisms do not have Usual microorganisms do not have common names since only scientist talk common names since only scientist talk about themabout them

Proof of pathogenicityProof of pathogenicityKoch’s postulatesKoch’s postulates

The symptoms and any evidence of the The symptoms and any evidence of the pathogen in the diseases host are carefully pathogen in the diseases host are carefully describeddescribed

The suspected pathogen is isolated from the The suspected pathogen is isolated from the host, a description is made.host, a description is made.

A healthy host is inoculated, describedA healthy host is inoculated, described

The pathogen is isolated and must be the same The pathogen is isolated and must be the same as originalas original

When all four steps are complete= proofWhen all four steps are complete= proof


Even though the cause was discovered, Even though the cause was discovered, they did not know how to treat itthey did not know how to treat it

The last major famine was 1916The last major famine was 1916

Copper was then known to protect crops Copper was then known to protect crops but it was needed to make bullets for the but it was needed to make bullets for the warwar

700,000 Germans died from starvation700,000 Germans died from starvation

Arrival of the potato in EuropeArrival of the potato in Europe

The potato was from the highlands of The potato was from the highlands of South America’s, Lake TiticacaSouth America’s, Lake Titicaca

It was discovered by the Spanish It was discovered by the Spanish Conquistadors while looking for goldConquistadors while looking for gold

The crop dates back to 400 B.C.The crop dates back to 400 B.C.

The first potatoes reached Europe about The first potatoes reached Europe about 15701570


New cultivars were developed New cultivars were developed

The potato was resistant for a few yearsThe potato was resistant for a few years

Then the blight returnedThen the blight returned

The blight develops a new race to attack The blight develops a new race to attack each new cultivareach new cultivar

The boom and bust cycle is the resultThe boom and bust cycle is the result

Lessons from the potato famineLessons from the potato famine

The disease triangle, plant, pathogen, The disease triangle, plant, pathogen, environmentenvironment

Disease

Susceptible Host

Favo

rabl

e env

ironm

ent

Virulent

Pathogen

HISTORY OF PLANT HISTORY OF PLANT PATHOLOGYPATHOLOGY

Tribes settled and began farmingTribes settled and began farming

In wet or dry years, small crops led to In wet or dry years, small crops led to faminefamine

Plant diseases are mentioned in the Bible Plant diseases are mentioned in the Bible (c750B.C.)(c750B.C.)

Sin was blamed for plant diseasesSin was blamed for plant diseases

The Greek philosopher Theophrastus (c The Greek philosopher Theophrastus (c 300B.C.)was the first to study and write 300B.C.)was the first to study and write about plant diseaseabout plant disease

History of Plant PathologyHistory of Plant Pathology

Nomadic tribes had to find enough Nomadic tribes had to find enough healthy foodhealthy food

Homer (c.1000 B.C.) mentioned the Homer (c.1000 B.C.) mentioned the therapeutic properties of sulfur on plant therapeutic properties of sulfur on plant diseasediseaseDemocritus (c. 470 B.C.) mentioned the Democritus (c. 470 B.C.) mentioned the control of blight by sprinkling olive grounds control of blight by sprinkling olive grounds on plantson plantsMost control was festivals and sacrificesMost control was festivals and sacrifices


Magnus A.D. 1200, Germany, proposed Magnus A.D. 1200, Germany, proposed that mistletoe was a parasitic plant but no that mistletoe was a parasitic plant but no one followed up on this.one followed up on this.French farmers (1600’s) and Connecticut French farmers (1600’s) and Connecticut farmers (1700’s) noticed that wheat rust farmers (1700’s) noticed that wheat rust was worse near barberry bushes.was worse near barberry bushes.(Alternate hosts)(Alternate hosts)Around 1667, Hooke (England) observed Around 1667, Hooke (England) observed the spores with a microscope.the spores with a microscope.


In Italy, Micheli (1729) described the In Italy, Micheli (1729) described the structures of fungi and noted that when he structures of fungi and noted that when he put the structure on fresh cut melon, they put the structure on fresh cut melon, they reproduced the same. He proposed that reproduced the same. He proposed that fungi arose from their own spores but no fungi arose from their own spores but no one believed him.one believed him.


In 1775 Tillet, in France showed that;In 1775 Tillet, in France showed that;

Wheat smut increased with the addition of Wheat smut increased with the addition of spores to the seeds spores to the seeds

The smut was reduced in seeds treated The smut was reduced in seeds treated with copper sulfatewith copper sulfate

He thought it was a poison rather than a He thought it was a poison rather than a microorganismmicroorganism


Provost, 1807 repeated Tillet’s work and Provost, 1807 repeated Tillet’s work and determined it was the spores that caused determined it was the spores that caused the fungus but the Science Academy the fungus but the Science Academy would not believe himwould not believe him

The thought they were the result rather The thought they were the result rather than the causethan the cause


Nematodes were first associated with Nematodes were first associated with disease by Needham in 1743disease by Needham in 1743

In 1855 the second nematode was In 1855 the second nematode was observed in cucumber root gallsobserved in cucumber root galls

Several more were discovered in the next Several more were discovered in the next 4 years4 years


In 1876 Pasteur and Koch in France showed In 1876 Pasteur and Koch in France showed that anthrax was caused by a bacteriumthat anthrax was caused by a bacterium

In 1878 Burill showed that fire blight was caused In 1878 Burill showed that fire blight was caused by bacteriumby bacterium

Acceptance was slow Acceptance was slow

In 1890’s Smith showed crown gall to be caused In 1890’s Smith showed crown gall to be caused by bacteriumby bacterium

In 1980 the process of crown gall was finally In 1980 the process of crown gall was finally explained, excessive hormone produce growthexplained, excessive hormone produce growth


Viruses Viruses

In1886 Mayer reproduced tobacco mosaic In1886 Mayer reproduced tobacco mosaic by injecting juice from a diseased plant by injecting juice from a diseased plant into a healthy one, he thought it was a into a healthy one, he thought it was a bacteriabacteria

In 1892 Ivanowski showed that it was not In 1892 Ivanowski showed that it was not a bacteria because it could go through a a bacteria because it could go through a bacteria sievebacteria sieve


In 1898 Beijerinck concluded that the In 1898 Beijerinck concluded that the mosaic was caused by a living fluid which mosaic was caused by a living fluid which he called a virushe called a virusIn 1935 Stanley separated the virus as In 1935 Stanley separated the virus as sediment in a flasksediment in a flaskThe first virus was seen with an electron The first virus was seen with an electron microscope in 1939 by Kauschemicroscope in 1939 by KauscheIn 1956, Gierrer and schramm removed In 1956, Gierrer and schramm removed protein from the virus and showed RNAprotein from the virus and showed RNA


In 1971 Diener discovered that potato In 1971 Diener discovered that potato spindle tuber disease was a naked single spindle tuber disease was a naked single strand circular molecule of infectious RNA strand circular molecule of infectious RNA which he called a viroidwhich he called a viroidAn even smaller infectious agent was An even smaller infectious agent was discovered by Prusiner in 1982 which he discovered by Prusiner in 1982 which he called a prioncalled a prionThree human diseases are caused by Three human diseases are caused by prions, non so far discovered in plantsprions, non so far discovered in plants


Protozoa were observed in Euphorbiaceae Protozoa were observed in Euphorbiaceae by Lafont in 1909by Lafont in 1909

1931 Stahel found flagellates in coffee 1931 Stahel found flagellates in coffee treestrees

1963 Vermeulen found evidence of 1963 Vermeulen found evidence of pathogenicity of flagellates in coffee trees pathogenicity of flagellates in coffee trees and coconutand coconut


Mollicutes were discovered in 1967Mollicutes were discovered in 1967

Doi and assoc observed wall-less Doi and assoc observed wall-less mycoplasmic bodies infecting plant mycoplasmic bodies infecting plant exhibiting witches broomexhibiting witches broom


There are many severe diseases for which There are many severe diseases for which no cause has been foundno cause has been found

Forest declineForest decline

Citrus blightCitrus blight

Spear rot of oil palmSpear rot of oil palm

Mango malformationMango malformation

All have unknown causesAll have unknown causes

History of Plant PathologyHistory of Plant Pathologythe experimental phasethe experimental phase

The importance of plant pathology was The importance of plant pathology was realized and added to the USDA offices in realized and added to the USDA offices in the late 1800’sthe late 1800’s

As knowledge accumulated, As knowledge accumulated, experimentation grew rapidly on ways to experimentation grew rapidly on ways to control or avoid plant diseasecontrol or avoid plant disease

History of Plant PathologyHistory of Plant Pathologythe etiological phasethe etiological phase

Involved observation and experiments to Involved observation and experiments to prove the causes of plant diseaseprove the causes of plant disease

This developed techniques for pure This developed techniques for pure cultures to satisfy Koch’s postulatescultures to satisfy Koch’s postulates

This phases depended on the This phases depended on the development of instrumentation and development of instrumentation and methodologymethodology

History of Plant PathologyHistory of Plant PathologyThe search for disease controlThe search for disease control

Even though the early people made Even though the early people made sacrifices to the gods , they did choose sacrifices to the gods , they did choose plants that were more resistant to diseaseplants that were more resistant to disease Recommendations for disease control Recommendations for disease control have been found as early as 1000B.C. have been found as early as 1000B.C. Homer, Democritus 470 B.C., and Homer, Democritus 470 B.C., and Theophrastus 300 B.C.Theophrastus 300 B.C.The 1600’s show the first reports of The 1600’s show the first reports of resistant varietiesresistant varieties


There were a lot of worthless cures There were a lot of worthless cures recommended but a few actually worked recommended but a few actually worked such as sulfursuch as sulfur

Seed saved from a ship wreck (1600’s)had Seed saved from a ship wreck (1600’s)had less smut disease than other plants so less smut disease than other plants so they started a seed pre-treat with brinethey started a seed pre-treat with brine

Later this was changed to copper sulfateLater this was changed to copper sulfate

This is still used todayThis is still used today


In the 1800’s lime sulfur was discovered.In the 1800’s lime sulfur was discovered.The story is a grape farmer made the The story is a grape farmer made the mixture to look like bird drops which he mixture to look like bird drops which he sprayed on his grapes so people walking sprayed on his grapes so people walking by the edge of the field would not eat by the edge of the field would not eat them.them.He soon noticed the plants that were He soon noticed the plants that were sprayed would not get diseased so he sprayed would not get diseased so he sprayed everythingsprayed everything


In 1913 organic mercury compounds were In 1913 organic mercury compounds were developed as seed treatments until developed as seed treatments until mercury was banned in the 1960’smercury was banned in the 1960’s

1934 a series of fungicides were 1934 a series of fungicides were developed; ferbam, zineb, manebdeveloped; ferbam, zineb, maneb

1965 the first systemic, carboxin was 1965 the first systemic, carboxin was discovereddiscovered

Antibiotics were discovered in 1950 & ‘67Antibiotics were discovered in 1950 & ‘67


In 1954 resistant bacteria strains were In 1954 resistant bacteria strains were discovereddiscovered

1963 resistant fungi were discovered1963 resistant fungi were discovered

1970’s new races of fungal pathogens 1970’s new races of fungal pathogens appearedappeared


Public concern developed in the 1950’sPublic concern developed in the 1950’sSome pesticides such as DDT were found Some pesticides such as DDT were found to be harmful to animals, especially birdsto be harmful to animals, especially birdsIt did not break down into harmless It did not break down into harmless materials as did most other pesticidesmaterials as did most other pesticidesIt and many others have since been It and many others have since been bannedbannedA book, The Silent Spring by Rachel A book, The Silent Spring by Rachel Carson raised public awarenessCarson raised public awareness


By the 1960’s all mercury was bannedBy the 1960’s all mercury was banned

DDT and chlorinated hydrocarbonsDDT and chlorinated hydrocarbons

Since 1980’s 80% of previous materials Since 1980’s 80% of previous materials have been bannedhave been banned

Damages, research, supply have raised Damages, research, supply have raised costscosts

Alternative controlsAlternative controls

Cultural practicesCultural practices Clean up debrisClean up debris Use certified seedUse certified seed Remove infected plant partsRemove infected plant parts Rotate cropsRotate crops Destroy weedsDestroy weeds Irrigate, etcIrrigate, etc I.P.M.I.P.M.

Alternative controlsAlternative controls

1928 Fleming reported that certain soil 1928 Fleming reported that certain soil borne fungi (Penicillium) inhibited the borne fungi (Penicillium) inhibited the growth of other fungi and bacteriagrowth of other fungi and bacteria

1930’s it was found if you inoculated a 1930’s it was found if you inoculated a plant with a mild form of virus, it would plant with a mild form of virus, it would protect the plant from the severe strainprotect the plant from the severe strain

1972 inoculation with non pathogenic 1972 inoculation with non pathogenic forms of bacteria and fungi prevent the forms of bacteria and fungi prevent the infection by pathogenic formsinfection by pathogenic forms

1980’s genetic engineering replaced the 1980’s genetic engineering replaced the former methodformer method

A new method is the use of A new method is the use of microorganisms or chemicals to form microorganisms or chemicals to form lesions which stimulate natural defenselesions which stimulate natural defense

Interest in the Mechanisms by Interest in the Mechanisms by Which Pathogens Cause DiseaseWhich Pathogens Cause Disease

Once it was realized the fungi etc caused Once it was realized the fungi etc caused the disease instead of the result, the the disease instead of the result, the mechanisms were studiedmechanisms were studied

1886 deBary noticed that host cells of 1886 deBary noticed that host cells of SclerotiniaSclerotinia died in advance of the died in advance of the pathogenpathogen

This was the discovery of toxins and This was the discovery of toxins and enzymes produced by the pathogenenzymes produced by the pathogen


1905 cytolytic enzymes were reported by 1905 cytolytic enzymes were reported by L.R. JonesL.R. Jones

1925 it was suggested that Pseudomonas 1925 it was suggested that Pseudomonas tabaci produced a toxin which caused tabaci produced a toxin which caused wildfire disease of tobaccowildfire disease of tobacco

1934 it was confirmed1934 it was confirmed

It was the first toxin to be isolated 1950’sIt was the first toxin to be isolated 1950’s


Many toxins and enzymes have since Many toxins and enzymes have since been foundbeen found

There have been many studies about the There have been many studies about the mechanisms by which the toxins or mechanisms by which the toxins or enzymes affect plants and,enzymes affect plants and,

Many studies about the defense Many studies about the defense mechanismsmechanisms


1939 IAA was discovered, a growth 1939 IAA was discovered, a growth regulator produced by a fungus regulator produced by a fungus GibberellaGibberella

It is now used in plant propagationIt is now used in plant propagation

1970’s-80’s Agrobacterium tumefaciens 1970’s-80’s Agrobacterium tumefaciens induces crown gall which does a natural induces crown gall which does a natural DNA transplantDNA transplant

It is now used in research and the It is now used in research and the production of pharmaceuticals production of pharmaceuticals

Genetic inheritance of Resistance Genetic inheritance of Resistance and Pathologyand Pathology

1894 Eriksson discovered different 1894 Eriksson discovered different biological races of Puccinia graminisbiological races of Puccinia graminis

They cannot be differentiated by sight but They cannot be differentiated by sight but by their hostsby their hosts

1905 Biffen reported inherited resistance1905 Biffen reported inherited resistance

1909 Orton distinguished between disease 1909 Orton distinguished between disease escape, endurance, and resistanceescape, endurance, and resistance


1911 Barrus showed genetic variability 1911 Barrus showed genetic variability within a pathogen specieswithin a pathogen species

1914 Stakmen et al explain resistance and 1914 Stakmen et al explain resistance and susceptibility of the same species in susceptibility of the same species in different geographical areasdifferent geographical areas

1946 Flor showed that for each gene in 1946 Flor showed that for each gene in the host for resistance there was a gene in the host for resistance there was a gene in the pathogen for virulence (gene-for-gene)the pathogen for virulence (gene-for-gene)


1963 Vanderplank described vertical 1963 Vanderplank described vertical resistance resistance Few genes, strong but only effect against a Few genes, strong but only effect against a

few racesfew races

Horizontal resistance, weaker but effective Horizontal resistance, weaker but effective against all racesagainst all races


1946 Gaumann proposed hypersensitivity 1946 Gaumann proposed hypersensitivity whereas and area around the site dies and whereas and area around the site dies and protects the rest of the plantprotects the rest of the plant

1960’s anti microbial substances was 1960’s anti microbial substances was proposed to existproposed to exist

Epidemiology of Plant Disease Epidemiology of Plant Disease Comes of AgeComes of Age

1944 Mills developed a table showing rain 1944 Mills developed a table showing rain and temperature and hoe it affected the and temperature and hoe it affected the development of apple scabdevelopment of apple scab

1963 Vanderplank wrote Plant Diseases: 1963 Vanderplank wrote Plant Diseases: Epidemics and Control, establishing and Epidemics and Control, establishing and important field of studyimportant field of study

It is now possible to predict epidemics by It is now possible to predict epidemics by keeping recordskeeping records

Epidemiology of Plant Disease Epidemiology of Plant Disease Comes of AgeComes of Age

1969 first computer simulation for early 1969 first computer simulation for early blight of tomato and potatoblight of tomato and potato

Since 1970’s many disease modeling and Since 1970’s many disease modeling and computer simulations have been computer simulations have been developed for many diseasesdeveloped for many diseases

Molecular Plant PathologyMolecular Plant Pathology

Since 1980’s most functions of genes Since 1980’s most functions of genes have been mapped and gene transfers have been mapped and gene transfers have been made to provide resistancehave been made to provide resistance

Early beginnings from 1956 when RNA of Early beginnings from 1956 when RNA of tobacco mosaic virus was shown to be tobacco mosaic virus was shown to be responsible for plant cell infectionresponsible for plant cell infection

1960’s study showed full genetic code for 1960’s study showed full genetic code for a certain amino acida certain amino acid


It was shown that two genes could be It was shown that two genes could be removed and replaced and expressed by removed and replaced and expressed by the plant cellsthe plant cells

Whole plants could be produced from a Whole plants could be produced from a single cellsingle cell

This is called tissue culture or propagationThis is called tissue culture or propagation


Foreign DNA can be moved to another Foreign DNA can be moved to another plant by using a virus or bacteria as a plant by using a virus or bacteria as a vectorvectorSince 1980’s segments of DNA have been Since 1980’s segments of DNA have been marked with radioactive isotopes and marked with radioactive isotopes and trackedtrackedWe now have many genetically We now have many genetically engineered plants such as corn and engineered plants such as corn and soybeanssoybeans

Development of Plant Pathology Development of Plant Pathology WorldwideWorldwide

Origins in late 1800’sOrigins in late 1800’s

1891Netherlands Society of Plant 1891Netherlands Society of Plant PathologyPathology

1895 Netherlands Journal of Plant 1895 Netherlands Journal of Plant PathologyPathology

1911 International journal named 1911 International journal named PhytopathologyPhytopathology


1916 Phytological Society of Japan1916 Phytological Society of Japan

Began publishing 1918Began publishing 1918

Canada 1930Canada 1930

India 1947India 1947


1968 International Society of Plant 1968 International Society of Plant Pathology was foundedPathology was founded

Most parts of the world have plant Most parts of the world have plant pathologists but a few parts have none pathologists but a few parts have none and do not practice controls so losses are and do not practice controls so losses are greatgreat

1940’s Rockefeller foundation started to 1940’s Rockefeller foundation started to help Mexican government help Mexican government


With great success in the program many With great success in the program many were soon to followwere soon to follow

It was impossible to have such It was impossible to have such foundations in every country so foundations in every country so international centers were formedinternational centers were formed


International Rice Institute, 1960 International Rice Institute, 1960 PhilippinesPhilippines

International Maize and Wheat International Maize and Wheat Improvement Center, 1966 MexicoImprovement Center, 1966 Mexico

International Institute of Tropical International Institute of Tropical Agriculture, 1968 NigeriaAgriculture, 1968 Nigeria

International Center of Tropical International Center of Tropical Agriculture, 1969 ColumbiaAgriculture, 1969 Columbia


More foundations were needed so a More foundations were needed so a consortium of donors was set up with the consortium of donors was set up with the World Bank…Consultative Group on World Bank…Consultative Group on International Agriculture ResearchInternational Agriculture Research

Numerous centers were established in Numerous centers were established in many countriesmany countries

Tropical countries are in special need Tropical countries are in special need because the weather promotes pathogensbecause the weather promotes pathogens

Trends in Teaching and Training in Trends in Teaching and Training in Plant PathologyPlant Pathology

First course in Plant Pathology was offered at First course in Plant Pathology was offered at Harvard by M.A. Farlow in 1875Harvard by M.A. Farlow in 1875Textbooks became common Textbooks became common Duggar 1906Duggar 1906Stevans and Hall 1921Stevans and Hall 1921Heald 1926 & ‘43Heald 1926 & ‘43Walker 1950Walker 1950Many specialized books appearedMany specialized books appearedB.S., M.S., and Ph.D. are available in Plant PathB.S., M.S., and Ph.D. are available in Plant Path

Education and Information Education and Information Technology in Plant PathologyTechnology in Plant Pathology

Many advances have been made in Many advances have been made in developing, collecting, organizing and developing, collecting, organizing and transmitting information by researchers, transmitting information by researchers, teachers etc.teachers etc.

Many data bases have been establishedMany data bases have been established

Plant Disease ClinicsPlant Disease Clinics

Most states have plant disease clinics Most states have plant disease clinics operated by plant pathology departments operated by plant pathology departments and county extension agentsand county extension agents

Since 1970 every state has at least one Since 1970 every state has at least one plant disease clinicplant disease clinic

Most are run by M.S. or Ph.D.’sMost are run by M.S. or Ph.D.’s

Most are run by the state department of Most are run by the state department of agricultureagriculture

Plant Pathology: The PracticePlant Pathology: The Practice

Most discoveries were and are made by Most discoveries were and are made by graduate students working on advance graduate students working on advance degreesdegreesThe actual practice of plant pathology is The actual practice of plant pathology is carried out at a lower level by technicians carried out at a lower level by technicians etc. who use the knowledge and etc. who use the knowledge and techniques of the researcherstechniques of the researchersThe knowledge etc. is transferred through The knowledge etc. is transferred through the county extension agentsthe county extension agents


Most growers receive limited informationMost growers receive limited informationIn the last 20 years, pesticide licensing In the last 20 years, pesticide licensing has increased the professional level of the has increased the professional level of the landscaperlandscaperThe author of your textbook predicts there The author of your textbook predicts there will be plant doctors on the same level as will be plant doctors on the same level as medical doctors. medical doctors. We have plant doctors now but are We have plant doctors now but are basically Ph.D’sbasically Ph.D’s


In the 1960’s-70’s licensing beganIn the 1960’s-70’s licensing began

Many horticulture/landscape associations Many horticulture/landscape associations have established certification programshave established certification programs

There is an American Registry of Plant There is an American Registry of Plant Pathologists governed by a board of Pathologists governed by a board of directorsdirectors


To be a certified plant pathologist you To be a certified plant pathologist you must have:must have:

B.S. + 5 years professional experienceB.S. + 5 years professional experience

M.S. + 3 years of professional experienceM.S. + 3 years of professional experience

Ph.D. + 1 year of professional experiencePh.D. + 1 year of professional experience

Or complete a recommended course of Or complete a recommended course of studystudy

Kinds and amounts of lossesKinds and amounts of losses

Plant disease is important because of the Plant disease is important because of the losses of food, fiber and other productslosses of food, fiber and other products

Plant loss affects the economyPlant loss affects the economy

People may starve to deathPeople may starve to death

Damage parks, recreational areas and Damage parks, recreational areas and buildingbuilding

Billions of pounds of pesticides are Billions of pounds of pesticides are produced and appliedproduced and applied


Plant diseases may limit the kinds of Plant diseases may limit the kinds of plants and industry in an areaplants and industry in an areaChestnut eliminated by blightChestnut eliminated by blightElm eliminated by Dutch elm diseaseElm eliminated by Dutch elm diseaseWhite birch only does well in the northWhite birch only does well in the northEuropean grape cannot be grown in European grape cannot be grown in southern U.Ssouthern U.SPlant disease has created whole new Plant disease has created whole new industry of pesticides and other businessindustry of pesticides and other business


Some plant disease makes the plant Some plant disease makes the plant poisonous to humans and animals such as poisonous to humans and animals such as ergot of rye and wheatergot of rye and wheatSeveral fungi will make hay poisonousSeveral fungi will make hay poisonousMay contain nematodes which carry virusMay contain nematodes which carry virusPlant disease causes great financial loss Plant disease causes great financial loss from a few % to total cropfrom a few % to total cropThe cost of disease control must be less The cost of disease control must be less than cost of crop lossthan cost of crop loss