What is Plant Pathology or Phytopathology

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What is Plant PathologyorPhytopathology?

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• Plant Pathology or
• Phytopathology is the
• study of plant
• diseases.

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• Did you know that plants
• have diseases and get
• sick just like people and
• animals do?

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• Most people dont realize
• that plants are affected by
• infectious diseases
• caused by living
• organisms (called Plant
• Pathogens).

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• Infectious plant
• pathogens include fungi,
• bacteria, nematodes,
• viruses, and parasitic
• plants.

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• Plant Diseases are also
• caused by non-living or
• abiotic causes such as
• air pollution, nutrient
• deficiencies and various
• environmental factors.

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Are Plant Diseases Important?YOU BET THEY ARE!!!

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• All of our food, much of
• our clothing, building
• materials, and much of
• the beauty in nature is
• provided by plants.

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• Plant diseases are a
• constant threat to the
• worlds food and fiber
• crops, forests, and
• landscape plants.

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• Throughout history, plant
• diseases have been
• responsible for the death and
• suffering of millions of people
• and countless animals.

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A few examples of devastating diseases are

• 1. Potato Late Blight
• 2. Ergot of Rye
• 3. Black Stem Rust of Wheat
• 4. Southern Corn Leaf Blight
• 5. Dutch Elm Disease
• 6. Bacterial Canker on Citrus
• 7. Plum Pox Virus on Stone Fruit
• All of these are infectious diseases caused by
  plant pathogens.

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• Lets take a closer look at a few of these
  important plant diseases

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Late Blight of PotatoCaused by the fungus
Phytophthora infestans

• The fungus killed most of the potatoes grown in
  Ireland during the mid 1800s.
• Potatoes were the main source of food for the
  Irish people.
• This plant disease resulted in the Irish Potato
  Famine of 1845
• 1 million people died
• 1.5 million people left Ireland

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Late Blight on Potato Tubers
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Ergot of RyeCaused by the fungus Claviceps
purpurea

• The pathogen produces a structure called a
  sclerotium that grows in place of the rye kernel.
  This sclerotium contains poisons that are very
  harmful to man and animals.
• The sclerotium is harvested with the rye grain.
  The grain is ground into flour, made into bread
  and is eaten by people. Eating the contaminated
  bread results in a disease called Ergotism.
• ERGOTISM OFTEN RESULTS IN DEATH.

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Ergot of Rye (note dark sclerotia)
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Ergot of Rye

• The scelotia also contains hallucinogenic
• compounds. People that eat ergot often see
  Fire.
• In the middle ages, people called the vision of
  fire induced by Ergot
• Holy Fire or St. Anthonys Fire
• Ergotism can also cause abortions and gangrene.
• THIS PLANT DISEASE IS STILL KILLING
• PEOPLE IN THE WORLD TODAY

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Black Stem Rust of Wheat

• 1916 - Destroyed 300 million
• bushels of wheat in the United States and
  Canada
• 1935 - Destroyed 135 million
• bushels in Dakotas and Minnesota
• SPORATIC EPIDEMICS STILL COST NORTH
• AMERICAN FARMERS BILLIONS OF DOLLARS

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Black Stem Rust of Wheat
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Southern Corn Leaf Blight

• 1970 - An epidemic caused a 15 loss of the
  U.S. corn crop. This resulted in a one
  billion dollar loss in the United States.
• This was enough corn that, if fed to cattle,
• it would make 30 BILLION HAMBURGERS

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Southern Corn Leaf Blight
Susceptible Plants
Resistant Plants
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Plum Pox Virus

• Plum Pox is caused by a virus and is a very
• serious disease that infects all stone fruit.
• - It is estimated that 100 million stone
  
• fruit trees are infected with the virus in
  
• Europe.
• - Infected trees become nonproductive
• and must be removed. This results in
• tremendous economic losses to stone
• fruit producers.

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Plum Pox Virus
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Plum Pox Virus

• In 1999, the virus was identified on peach trees
  in Pennsylvania. This is the first observation
  of the virus in North America.
• The virus was probably introduced into the U. S.
  in an infected tree or budwood. The disease is a
  major threat to stone fruit production throughout
  North America.
• At present, plant pathologists and regulatory
  agencies are trying to eradicate the virus.

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• Plant diseases cause an
• estimated loss of 8 billion
• dollars per year in the
• United States alone.

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What Can We Do About Plant Diseases?

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• We rely upon Plant Pathologists to provide
  information about plant diseases and how to
  manage them.

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• A Plant Pathologist is a professional who
  specializes in plant health much as a physician
  specializes in human health or a veterinarian in
  animal health.

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• Controlling plant diseases and keeping plants
  healthy is the main objective of a plant
  pathologist.

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• Controlling plant disease requires an
  understanding of the agents that cause disease as
  well as an understanding of how plants are
  affected by disease.

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• Through college courses in botany, microbiology,
  horticulture, crop science, soil science,
  ecology, genetics, biochemistry, molecular
  biology, and physiology, students receive the
  necessary background for exciting careers in the
  interdisciplinary science of plant pathology.

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• Plant pathologists are employed by colleges and
  universities, state and federal agencies,
  industrial firms, international institutes, and
  as private practitioners.

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Most Plant Pathologists are members of

• The American
• Phytopathological Society
• (APS)

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• APS is an international scientific organization
  devoted to the study of plant diseases and their
  control.

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• The society has a membership of nearly 5000
  plant pathologists and other scientists located
  in 80 countries worldwide.

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• The common goal of APS and Plant Pathologists
  worldwide is to develop and promote knowledge
  about plant diseases and their control.

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• We should all remember that we need HEALTHY
  PLANTS in order to have HEALTHY AND HAPPY PEOPLE.