This document discusses plant pathology and the importance of plant diseases. It begins by defining plant pathology as the scientific study of plant diseases caused by pathogens and environmental conditions. It then lists common pathogens like fungi, bacteria, viruses, and nematodes. The document emphasizes that plant diseases are paramount to humans because they damage crops essential for food, clothing, shelter and more. For millions globally still dependent on their own crops, diseases can mean the difference between comfortable living and starvation or death. Examples given include the Irish Potato Famine and ongoing hunger in developing nations today. The document also notes economic losses to growers in food-secure nations and the effects of increased prices on consumers, as well as environmental pollution from pesticides used to control

1. Presenter: Saeed Mohaned Nor
Student at Benadir university, Somalia.
Faculty of Agriculture.
Email: saciidroyal@gmail.com

2.  Introduction
 Losses caused by plant diseases
 Disease triangel.

3.  Plant pathology is the scientific learning of
diseases in plants caused by
pathogenes (infectious organisms) and
environmental conditions (physiological
factors).
Organisms that cause infectious disease include:
fungi, oomycetes, bacteria, viruses,
viroids,Phytoplasmas,protozoa, nematodes and
parasitic plants.

4. Key terms
Pathogen: An agent that causes disease.
Host: an organism that has been infected by a
pathogen.
Pathogenicity: the ability to cause a disease.

5.  Plant diseases are of paramount importance to
humans because they damage plants and plant
products on
which humans depend for food, clothing,
furniture, the environment, and, in many cases,
housing. For millions of people all over the
world who still depend on their own plant
produce for survival, plant diseases can make
the difference between a comfortable life and a
life haunted by hunger or even death from
starvation.

6.  Death from starvation of one and a quarter
million Irish people in 1845 and much of the
hunger of the underfed millions living in the
developing countries today are examples of the
consequences of plant diseases. For countries
where food is plentiful, plant diseases are
significant primarily because they cause
economic losses to growers.
Plant diseases, however, also result in increased
prices of products to consumers;

7.  they sometimes cause direct and severe
pathological effects on humans and animals
that eat diseased plant products; they destroy
the beauty of the environment by damaging
plants around homes, along streets, in parks,
and in forests; and, in trying to control the
diseases, people release billions of pounds of
toxic pesticides that pollute the water and the
environment.

8.  Plant Diseases Reduce the Quantity and
Quality of Plant Produce.
 Plant Diseases May Limit the Kinds of Plants
and Industries in an Area.
 Plant Diseases May Make Plants Poisonous to
Humans and Animals.
 Plant Diseases May Cause Financial Losses.