What is Plant What is Plant PathologyPathology

ororPhytopathology?Phytopathology?

Plant Pathology Plant Pathology or

PhytopathologyPhytopathology is the

study of plant

diseases.

Did you know that plantsDid you know that plants

have diseases and gethave diseases and get

sick just like people andsick just like people and

animals do?animals do?

Most people don’t realizethat plants are affected byinfectious diseasescaused by livingorganisms (called PlantPlantPathogensPathogens).

Infectious plantpathogens include fungi, fungi, bacteria, nematodes,bacteria, nematodes,viruses, and parasiticviruses, and parasiticplants.plants.

Plant Diseases are also

caused by non-living or

abiotic causes such as

air pollution, nutrientair pollution, nutrient

deficiencies and variousdeficiencies and various

environmental factors.environmental factors.

Are Plant Diseases Are Plant Diseases Important?Important?

YOU BET THEY ARE!!!

All of our food, much of

our clothing, building

materials, and much of

the beauty in nature is

provided by plants.

Plant diseases are aconstant threat to theworld’s food and fibercrops, forests, andlandscape plants.

Throughout history, plant

diseases have been

responsible for the death and

suffering of millions of people

and countless animals.

A few examples of devastating

diseases are: 1. Potato Late BlightPotato Late Blight 2. Ergot of RyeErgot of Rye 3. Black Stem Rust of WheatBlack Stem Rust of Wheat 4. Southern Corn Leaf BlightSouthern Corn Leaf Blight 5. Dutch Elm DiseaseDutch Elm Disease 6. Bacterial Canker on CitrusBacterial Canker on Citrus 7. Plum Pox Virus on Stone Fruit Plum Pox Virus on Stone Fruit

All of these are infectious diseases

caused by plant pathogens.

Let’s take a closer look at a few of these important important plant diseasesplant diseases

Late Blight of PotatoLate Blight of PotatoCaused by the fungus Phytophthora infestans

• The fungus killed most of the potatoes grown in Ireland during the mid 1800’s.

• 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 died1.5 million people left Ireland

Late Blight on Potato TubersLate Blight on Potato Tubers

Ergot of RyeErgot 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 ErgotismErgotism. .

ERGOTISM OFTEN RESULTS IN DEATH.ERGOTISM OFTEN RESULTS IN DEATH.

Ergot of RyeErgot of Rye(note dark sclerotia)(note dark sclerotia)

Ergot of RyeErgot of RyeThe scelotia also contains hallucinogenic

compounds. People that eat ergot often see FireFire.

In the middle ages, people called the vision of fire induced by Ergot

Holy Fire or St. Anthony’s FireHoly Fire or St. Anthony’s Fire

Ergotism can also cause abortions and gangrene.

THIS PLANT DISEASE IS STILL KILLING PEOPLE IN THE WORLD TODAY

Black Stem Rust of WheatBlack Stem Rust of Wheat1916 - Destroyed 300 million

bushels of wheat in the United States and Canada

1935 - Destroyed 135 millionbushels in Dakotas and Minnesota

SPORATIC EPIDEMICS STILL COST NORTHAMERICAN FARMERS BILLIONS OF

DOLLARS

Black Stem Rust of WheatBlack Stem Rust of Wheat

Southern Corn Leaf BlightSouthern 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

Southern Corn Leaf BlightSouthern Corn Leaf Blight

SusceptibleSusceptiblePlantsPlants

ResistantResistantPlantsPlants

Plum Pox VirusPlum Pox VirusPlum PoxPlum 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.

Plum Pox VirusPlum Pox Virus

Plum Pox VirusPlum Pox VirusIn 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.

Plant diseases cause an

estimated loss of 8 billion8 billion

dollarsdollars per year in the

United States alone.

What Can We Do What Can We Do About Plant About Plant Diseases?Diseases?

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

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

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

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

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

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

Most Plant Pathologists are members of

The American The American

Phytopathological SocietyPhytopathological Society

(APS)(APS)

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

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

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

We should all remember that we need HEALTHY HEALTHY PLANTSPLANTS in order to have HEALTHY AND HAPPY HEALTHY AND HAPPY PEOPLEPEOPLE.