Thursday, May 21, 2020

HISTORY OF PLANT PATHOLOGY











 




HISTORY OF PLANT PATHOLOGY:
 

Ancient period:
A literature of European and vedic eras will give us some information on the plant 
diseases and their control measures. Greek philosopher Theophrastus recorded some 
observations on the plant diseases in his book enquiry into plants. His experiences were 
mostly based on imagination and observation but not on experimentation. He had 
mentioned that plants of different groups have different diseases which were autonomous 
or spontaneous, i.e., no external cause was associated. 
In India, the information on plant diseases is available in ancient literature such as 
rigveda, atharveda (1500-500BC), arthasashtra of Kautilya (321-186 BC), Sushruta 
sanhita (200-500AD), Vishnupuran (500AD), Agnipuran (500-700AD), Vishnu 
dharmottar (500-700AD), etc. In Rigveda, not only the classification of plant diseases has 
been given but the germ theory of disease was also advocated. 
Vriksha ayurveda by Surpal in ancient India is the first book in which lot of 
information on plant diseases is available. In this book, plant diseases were categorized 
into two groups, internal (probably physiological diseases) and external (probably 
infectious diseases). External diseases were supposed to be due to attack of 
microorganisms and insects. In this book, a mention of treatments for different diseases 
caused by different agencies was prescribed which were based on superstition as well as 
scientific observation. Hygiene, tree surgery, protective covering with pastes and special 
culture of plants are practices which are still recommended. In chemical treatments, use 
of honey, ghee, milk, barley flour, pastes made from herbs, plant extracts, etc., were 
recommended. For the control of root diseases, oilcakes of mahuva, mustard, sesame, 
castor, etc., were used. 
Symptoms of plant diseases such as rust, downy mildew, powdery mildew and blight are 
often mentioned in the bible, Shakesphere’s poems and dramas of other Christian 
literature. In Jataka of Buddhism, Raghuvansh of Kalidas there was also a mention about 
different symptoms of plant diseases. 
In Europe and other western countries, after the time of Theophrastus (about 286 BC) no 
definite opinion could be formed about plant disease for the next 2000 years. In ancient 
period, the plant diseases were attributed to many causes which include divine power, 
religious belief, superstition, effect of stars and moon, bad wind and wrath of god, etc.


PRE-MODERN PERIOD

1) PIER ANTONIO MICHELLI (Italian):


  • He was an Italian botanist.
  • He was the founder and father of Mycology. 
  •  He was the first person who observed fungal spores for the first time and conducted many spore germination studies (by growing fungus organisms on 
    freshly cut pieces of melons and pears).
  •  He was the first person who observed Cystidia on the lamellar edge or hymenial layer of Agaricales. 
  • In 1729 he published a book “Nova Plantarum Genera” in which he gave descriptions about 1900 species in Latin out of which 900 were fungi. The important genera are Aspergillus niger, Botrytis sps., Polyporus sps. etc. 

2) TILLET (French) 
  • In 1755, he published a paper on bunt or stinking smut of wheat.

   
  •  By well planned experiments he proved that wheat seeds that contained black powder on their surface produced more diseased plants than clean seeds. 
  •  He emphasized that bunt was an infectious disease and it was closely related with fungus. However, he believed that the disease was caused by some toxin produced by the black powder. He did not know that the black powder contained the spore mass of the fungus. 
  • He reported that the chemical treatment of seeds with common salt and lime inhibited the contagious activity. 


MODERN PERIOD

1) BENEDICT PREVOST (French):
  • He proved that diseases are caused by micro-organisms.
  •  He studied wheat bunt disease for about 10 years and in 1807, he published his findings in the paper “memoir on the immediate cause of bunt or smut of wheat and of several other diseases of plants and on preventives of bunt” 
  • He proved that the bunt of wheat was caused by the fungus Tilletia caries
  • Studied and observed the germination of bunt species. He confirmed the findings of Tillet by mixing the spores of fungus with clean seeds. 
  •  Discovered the life cycle of bunt fungus
  •  He showed that the solution containing copper sulphate prevented the germination of bunt spores and can be used for control of bunt diseases. 
  •  He mentioned the fungicidal and fungistatic properties of chemical treatments 
2) CHRISTIAN HENDRICK PERSOON (1761-1831): 
  • Person first published observations Mycologicae. 
  •  In 1801, he published “Synopsis methodica fungorum” for nomenclature of Ustilaginales, Uredinales and Gasteromycetes. 
  •  He also published Mycologica Europica in 1822. 
  • He gave the name to rust pathogen of wheat as Puccinia graminis. 
3) ELIAS MAGNUS FRIES (1821): 
  • He published three volumes of “Systema Mycologium” for nomenclature of hymenomycetes. 
  • Person and fries first time introduced binomial system of nomenclature to classify the fungal organisms. 
During 1830-1845, when late blight of potato was fast spreading in England, Ireland and 
continental Europe, there was no one opinion among the scientists about the disease-fungus relationship. 

1) ANTON De BARY (Germany):


  •  He was the father and founder of modern Mycology
  •  He was the founder of modern experimental plant pathology.
  •  In 1863, he studied the epidemics of late blight and renamed the casual organism as Phytophthora infestans.
  •  He discovered heteroecious nature of rust fungi (1865). 
  • He gave detailed account on life cycles of downy mildew genera. 
  • He studied about vegetable rotting fungi and damping off fungi
  •  He wrote a book named “Morphology and Physiology of fungi, lichens and Myxomycetes” (1866). 
  • He reported the role of enzymes and toxins in tissue disintegration caused by Sclerotinia sclerotiorum

Students of De Bary

1. Marshal Ward (UK) - Studied coffee rusts and its epidemics 

2. M.S. Woronin (USSR) - Studied about life cycle of club root fungi, 
 i.e, Plasmodiophora brassica.

3. Farlow - Fungi and bibliography. He established 
 Farlow cryptogamic herbarium. Farlow, 
 first introduced independent course of plant 
 pathology at Harward University. 
 
4. Millardet - Discovered Bordeaux mixture for the 
 control of downy mildew of grapevine.

Oscar Brefeld, a colleague of De Bary (Germany) -Pioneer in pure culture techniques.


2) E. J. Butler (Edwin John Butler):


  •  He was the father of modern plant pathology and father of Indian Mycology.
  •  He worked at IARI for 20 years from 1901 to 1920. 
  • He was the founder and first director of imperial Mycological institute, Kew, England (1920-35). 
  • Monograph: Pythiaceous and allied fungi. 
  • Books: a) Fungi and Disease in Plants (1918)                                                           b) Fungi in India (with B.R.Bisby) and 
           c)  Plant Pathology (with S.G.Jones). 

3) E.C. STAKMAN :


  • He studies the variability in rust fungus. Contributed valuable information on physiological races of pathogen 
  •  He concluded that due to continuous evolution of races and biotypes in the species of the rust fungus its pathogenic capability goes on changing and as a result the resistant capability of the host also changes. 
4) T. J. BURRUILL (USA): 
He proved for the first time that fire blight of apple and 
pear was caused by a bacterium (now known as Erwinia amylovora).

5) E.F.SMITH (U.S.A):


  • He gave the final proof of the fact that bacteria could be incitants of plant diseases. 
  •  He also worked on the bacterial wilt of cucurbits and crown gall disease. He is also called as "Father of Phytobacteriology". 
  •  In 1981, he demonstrated for the first time that budding or grafting could be another method of transmission of plant viruses. 
  •  He showed the contagious nature of peach yellows. 
6) DOI AND ISHIE (JAPANESE):
  •  They found that mycoplasma like organisms (MLO) could be responsible for the disease of the yellows type. 
  •  Doi observed that MLO's are constantly present in phloem while Ishie observed MLO's temporarily disappeared when the plants are treated with tetracycline antibodies. 
7) BEIJERINCK (Dutch):


  •  Founder of virology 
  •  He proved that the virus inciting tobacco mosaic is not a living microorganism. 
  •  He believed it to be contagium vivum fluidum (infectious living fluid) 
8) W.H.STANLEY:



  • In 1935, he proved that viruses can be crystallised. He got Nobel Prize. 
  • He treated the sap from diseased leaves of tobacco with ammonium sulphate and obtained a crystalline protein which, when placed on healthy tobacco leaves, could reproduce the disease. 
  •  He finally proved that viruses are not living micro-organisms because no living form can be chemically treated and crystallized and still remain viable. 
9) BAWDEN F.E. and PIRIE (Britain): 

They found that the crystalline nature of the 
virus contains nucleic acid and protein. 

10) DIENER and RAYMER discovered the potato spindle tuber was caused by small 
naked ssRNA which he called viroid.


INDIAN SCIENTISTS

1) B.B MUNDKUR:


  •  He worked on the control of cotton wilt diseases. 
  • He is responsible for the identification and classification of large number of Indian smut fungi
  • He started Indian Phytopathological Society in 1948 and published a journal Indian Phytopathology
  • His book – Fungi and Plant diseases
2) J.F.DASTUR:


  • First Indian plant pathologist who was credited for his detailed studies on fungi and plant diseases. 
  • He studied the characters of Phytophthora and Phytophthora diseases of potato and castor. 
  •  He established Phytophthora parasitica from castor. 
3) K.C. MEHTA – Life cycle of cereal rusts in India 

4) T.S. SADASIVAN:


  • Started the studies on bio-chemistry of host-parasite relationship at University of Madras 
  •  Contributed to the concept of vivotoxins 
  • Studied on mechanism of wilting in cotton by Fusarium vasinfectum. The production of fusaric acid by this fungus outside the host was demonstrated.










 

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