It is the study of weeds, their biology and their control, whether it be manual, mechanical, cultural, biologival, chemical or ecological.

The following are the areas of weed science research, except:

Greek "pathos"

Greek "logos"

;It is the mechanisms by which these factors induce disease in plants ;and of the methods of preventing or controlling disease and reducing the damage it causes.

It looks into the characteristics of diseases, their causes, plant-pathogen interactions, factors affecting disease development in individual plants and in populations, and the various means of controlling diseases.

It deals with the application of the knowledge gained from studying the science.

The raison d'etre or ultimate objective of plant pathology:

Disease that cause famine and death of more than a million people in Ireland.

it is the nemesis of corn

Whetzel (1929) called the malfunctioning caused by nonliving or inanimate agents as:

Any agent (biotic or abiotic) that causes a disease.

An organism which depends wholly or partly on another living organism for its food. Most of these kind of organisms are pathogens.

An organism that is restricted to subsist on living organisms and attacks only living tissues.

An organism which has the ability to become a parasite although it is a saprophyte.

An organism that lives on dead organic or inorganic matter.

An organism that has the ability to become a saprophyte but is ordinarily a parasite.

A plant being attacked by a parasite. A food relationship with a parasite (pathogen) is implied.

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

the capacity of a pathogen to cause disease.

disease development in the plant.