Concepts of Plant Disease

CONCEPTS OF
PLANT DISEASE

Plant Pathology :

AgSci 03- Crop Protection

Prepared by: Rachelle Ann F. Gamueda

LEARNING OBJECTIVES

At the end of the lesson, students should be able to:

• Describe the disease triangle;

• Explain the importance of plant disease concept;

• List the required conditions for a plant disease to

occur.

Multiple Choice

A host that do not show Irrespective of environment

• Symptom-less Carrier
• Asymptomatic Carrier

GAME!
Guess the word
by filling the box

Open Ended

What is Plant Pathology?

PLANT PATHOLOGY

Plant Pathology is the study of plant
diseases including: Causes,Mechanisms by which diseases occur,Interactions between plants and disease- causing agents, and Controlling diseases.

Word Cloud

Who is the Father of Plant Pathology?

Father of Plant Pathology

Heinrich Anton de Bary
is known as the Father of mycology and Father of Plant pathology (Phytopathology).

Open Ended

What is Plant Disease?

PLANT DISEASE

Plant disease is a
condition of plant deterioration and damage
caused by various abiotic and biotic factors.

ABIOTIC

Non-living Components

Consisting of Living Organisms

BIOTIC

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Plant Disease Diagnosis

Plant Disease Diagnosis

The identification of symptoms and signs helps determine the type of pathogen involved and the appropriate control measures to take.

A physiological malfunctioning

caused by animate

Any deviation from normal growth or structure of plants that is sufficiently pronounced and
permanent to produce visible symptoms or to impair quality or economic value impair quality or economic value.

(Stakman and Harrar, 1975).

(Whetzel, 1972)

A dynamic interaction between an organisms and

its environment which results in abnormal

physiology an often morphological or neurological

changes in the organisms

A malfunctioning process cause

by continuous irritation.

(Horsfall and Dimond, 1975).

(Merril)

Any disturbance brought about by a pathogen or an

environmental factor which interferes with manufacture,
translocation, or utilization of food, mineral nutrients and

water in such a way that the affected plant of the same

variety

It is a harmful alteration of the normal

physiological and biochemical development

of a plant.

(National Academy of Science, 1976)

(Agrios, 1978).

The salient points in most definition of

diseases are:

a) The present of physiological disorders
that are generally detrimental; and

b) Morphological abnormalities result
from the physiological malfunctioning

Open Ended

What is Plant Disease Triangle?

PLANT DISEASE

TRIANGLE

DISEASE TRIANGLE

DISEASE

Word Cloud

What are the component to form a disease?

Definition and Terminology

in

PLANT PATHOLOGY

Multiple Choice

Is any agent that causes a disease is generally referred to as living organisms such as fungus or bacterium that causes disease

• PATHOGEN

• PARASITE

Is any agent that
causes a disease is

generally referred to as
living organisms such
as fungus or bacterium

that causes disease

PATHOGEN

Multiple Choice

An organism which depend wholly or partly on other living organisms for its food

• PARASITE

• HETEROTROPH

PARASITE

An organism which
depend wholly or

partly on other living

organisms for its

food.

Obligate parasite

Is an organisms that is restricted to subsist on
living organisms and attacks only living tissues.

Facultative parasite

Is organisms, which has the faculty or ability to

be a parasite although it is ordinarily a

saprophyte

Multiple Choice

 Is organism that lives on dead or inorganic matter.

• SAPROPHYTE

• Decomposer

Is organism that lives on dead
or inorganic matter.

SAPROPHYTE

Multiple Choice

Refers to a plant that is attacked by a parasite

• Parasitic plant
• Host plant

HOST

refers to a plant

that is attacked by

a parasite

Multiple Choice

Those environmental factors that are able to cause plant diseases.

• PHYSIOPATHOGEN

• PATHOGEN

Those environmental factors
that are able to cause plant

diseases.

Ex. Temperature, Humidity, Moisture,
Light, Soil conditions.

PHYSIOPATHOGEN

Multiple Choice

The capacity of the pathogen to cause disease

• PATHOGENICITY

• PATHOGENESIS

PATHOGENICITY

The capacity of the
pathogen to cause

disease

Multiple Choice

Is the chain of interrelated events of disease development.

• Etiology
• Pathogenesis

Events of disease Is the chain of interrelated events of disease development.

PATHOGENESIS

Multiple Choice

A plant that is susceptible to a disease whether or not the pathogen is parasitic

• SUSCEPT

• SUSCEPTABLE

SUSCEPT

A plant that is

susceptible to a disease

whether or not the

pathogen is parasitic

Multiple Choice

Refers to the quantitative amount of disease that can isolate of a given pathogen can cause in a given group of plants in terms of size of lesions or number of lesions.

• VIRULENCE

• AGGRESSIVENESS

Refers to the quantitative
amount of disease that can
isolate of a given pathogen can cause in a given group of plants in terms of size of

lesions or number of lesions.

VIRULENCE

Multiple Choice

Measures the rate at which virulence is expressed by a given pathogenic

Isolate.

• AGGRESSIVENESS

• WEAKNESS

AGGRESSIVENESS

Measures the rate at which
virulence is expressed by a

given pathogenic

Isolate.

Multiple Choice

Inherent ability of an organism to overcome in any degree the effects

of a pathogen

• Immunity
• Disease resistance

Inherent ability of an

organism to

overcome in any
degree the effects

of a pathogen

DISEASE RESISTANCE

Multiple Choice

The inability to overcome the effects of a pathogen

• Immunity
• Susceptibility

SUSCEPTIBILITY

The inability to

overcome the effects

of a pathogen

Multiple Choice

Ability of plant to withstand the severe effects of the pathogen without experiencing a severe reduction in yield

• TOLERANCE

• Disease resistance

Ability of plant to

withstand the severe

effects of the pathogen
without experiencing a

severe reduction in

yield

TOLERANCE

Multiple Choice

Symptoms not expressed due to unfavorable condition

• TRAITS

• MASKED SYMPTOMS

MASKED SYMPTOMS

Symptoms not

expressed due to

unfavorable condition

Open Ended

What is Disease Triangle

Word Cloud

What are required conditions for a plant disease to occur?

Word Cloud

List or give the terms that we discussed this afternoon.

ASSIGNMENT

1.What are the symptoms and signs of plant diseases?

2. Search for 10 common symptoms and signs of plant diseases here in the Philippines.

Evaluation

Explain the Plant Disease Triangle

in your own words.

THANK YOU!

I hope you learn something new today!