MIC 319 FUNDAMENTALS OF

AGRICULTURAL MICROBIOLOGY

CHAPTER 1 INTRODUCTION TO PLANT

PATHOLOGY BY

SITI NORAZURA JAMAL 03 006/ 06 483 2132

norazura6775@ns.uitm.edu.my

Outline

• Plant pathology definition

• Plant disease definition

• Plant diseases classification

PLANT PATHOLOGY

PLANT PATHOLOGY

• Also be referred as “PHYTOPATHOLOGY”.

• A science that study plant disease

• The disease are caused by pathogens (infectious diseases) and environmental conditions (physiological factors)

• Improve the chances of plant survival

PLANT DISEASE

Definition

“ A malfunctioning process that is caused by continuos irritation and produce symptoms”

(Horsfall & Cowling)

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

(Stakman & Harrar)

Definition

Healthy plant

• The ability to carry out normal physiological functions at a acceptable level consistent to genetic potential

Sick/diseased plant

• A multifunctioning process that is caused by continuous irritation and produce symptoms

Healthy plant

• Normal physiological functions include: Normal cell division, differentiation &

development Absorption of water and minerals from the soil

and translocation Photosynthesis and translocation of

photosynthesis Utilization and storage of photosynthates Reproduction

Healthy plant

Sick/diseased plant

• A plant would not have all of these at once.

• Plant disease is any disruption (biotic or abiotic) of the plants normal metabolism.

Sick/diseased plant

“ the malfunctioning of host cells and tissues that results from their continuous irritation by a pathogenic agent or environmental factor and leads to the development of symptoms.

“ disease in a condition involving abnormal changes in the form, physiology, integrity, or behavior of the plant.’

“ such changes may result in partial impairment or death of the plant or its parts’

(George N.Agrios)

Sick/Diseased plant

Healthy plant vs diseased plant

Plant diseases classification

Classification of plant disease

Infectious Non infectious

Infectious disease

• A disease that is caused by a pathogen that can spread from a diseased to healthy plant

• Disease that is caused by living organism .

• E.g. Pectobacterium atrosepticum (potato pathogen)

Non infectious disease

• Disease that is caused by non living organism • Could not be spread to other healthy plant • E.g. factors: Too low/high temperature Lack/excess of soil moisture Air pollution Nutrient deficiencies Mineral toxicities Soil acidity or alkalinity