Definition and History of plant pathology

Definition:- it is the science which deals with the study of living entities and environment conditions that cause diseases in plants, mechanism by which these factors produce disease in plant, interaction between disease causing agent and diseased plants and method of preventing or managing disease and alleviating the damage it cause.

Symptom:-  external or internal reaction or alteration of a plant as a result of a disease  is called symptom e.g. wilting, curling, puckering.

Sign :- pathogen or its part or product (i.e. vegetable or fruiting structure of the pathogen) seen on a host plant e.g. rust, smut , spore etc is called sign.

Disease:- According to E.C. Stakman and J.George Harrar in 1957. A plant disease is the physiological disorder or structural abnormality i.e. deleterious to the plant or of its part or its products that reduces its economic value.

                  According to Agrios (2005) “Disease is a malfunctioning process. He defined it as the series of visible and invisible responses of plant cells and tissues to a pathogenic organism or environmental factor that result in adverse change in the form, function or integrity of plant and may lead to the partial impairment or death of plant part or entire plant’’  

History of plant pathology

Year period	scientist	contribution
1871	kuhn	Used carbon disulfide to control sugar beet cyst nematodes
1667	Hooke	First to observe spores of rust fungus with the help of compound microscope in england
1884	H.C. Gram	Gram staining
1885	Millardet	Discovered Bordeaux mixture for the control of downy mildew of grapevine and later, used against many diseases including late blight of potato.
1743 AD	Needham	First plant parasitic nematode- Anguina tritici on wheat.
1886	E.J. Butler	Father of Modern plant pathology-detailed studies on Indian fungi and disease for 20 years in ‘The imperial agri. Institute’ at Pusa.
1875	Robert Koch	Establishment pathogenicity rules known as ‘koch’s Postulates; known as the ‘Father of microbial techniques for his outstanding contributions in microbiology
1892	Lwanowski	Demonstrated that TMV could pass through the filters which retain bacterial cells; stated that viruses are smaller than bacteria.
1918	E.J. Butler	Father of modern plant pathology in India-authored ‘fungi and disease in plants; a monograph on pythiaceous and allied fungi; scientific study of several plant diseases
1950	J.C. Luthra	Developed solar treatment of wheat seeds to control loose smut in india
1963	Vanderplank	Establishment epidemiology as a major factor in plant disease development in book plant diseases; Epidemics and control, also reported the occurance of vertical and horizon resistance, in plants against pathogens.
1966	Kassanis	Discovery of satellite virus.
1967-1971	T.O. Diener and Raymer	First to report viroid as a causal agent of potato spindle tuber diseases.