Blight is a specific
symptom
Signs and symptoms are diagnostic indications of an illness, injury, or condition.
Signs are objective and externally observable; symptoms are a person's reported subjective experiences.
A sign for example may be a higher or lower temperature ...
affecting
plant
Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...
s in response to infection by a
pathogenic organism
An organism is any life, living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have be ...
.
Description
Blight is a rapid and complete
chlorosis, browning, then death of plant
tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this symptom are called blights. Several notable examples are:
*
Late blight of potato, caused by the
water mold ''
Phytophthora infestans'' (Mont.) de Bary, the disease which led to the
Great Irish Famine
* Southern corn leaf blight, caused by the
fungus
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
''
Cochliobolus heterostrophus'' (Drechs.) Drechs,
anamorph ''
Bipolaris maydis'' (Nisikado & Miyake) Shoemaker, incited a severe loss of corn in the United States in 1970.
*
Chestnut blight, caused by the fungus ''Cryphonectria parasitica'' (Murrill) Barr, has nearly completely eradicated mature
American chestnuts in North America.
*
Citrus blight, caused by an unknown agent, infects all citrus
scions.
*
Fire blight of pome fruits, caused by the
bacterium ''
Erwinia amylovora'' (Burrill) Winslow et al., is the most severe disease of
pear
Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosaceae, bearing the Pome, po ...
and also is found in
apple
An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...
and
raspberry
The raspberry is the edible fruit of several plant species in the genus ''Rubus'' of the Rosaceae, rose family, most of which are in the subgenus ''Rubus#Modern classification, Idaeobatus''. The name also applies to these plants themselves. Ras ...
, among others.
* Bacterial leaf blight of
rice
Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
, caused by the bacterium ''
Xanthomonas oryzae'' (Uyeda & Ishiyama) Dowson.
* Bacterial seedling blight of rice (''Oryza sativa''), caused by pathogen ''
Burkholderia plantarii''
* Early blight of potato and tomato, caused by species of the ubiquitous fungal genus ''
Alternaria
''Alternaria'' is a genus of Deuteromycetes fungi. All species are known as major Phytopathology, plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead t ...
''
* Leaf blight of the grasses e.g. ''
Ascochyta'' species and ''
Alternaria triticina'' that causes blight in wheat
*
Bur oak blight, caused by the fungal pathogen ''Tubakia iowensis''.
* South American leaf blight, caused by the
ascomycete ''
Pseudocercospora ulei'',
also called ''Microcyclus ulei'', ended the cultivation of the rubber tree (''
Hevea brasiliensis'') in South America.
On leaf tissue, symptoms of blight are the initial appearance of lesions which rapidly engulf surrounding tissue. However,
leaf spots may, in advanced stages, expand to kill entire areas of leaf tissue and thus exhibit blight symptoms.
Blights are often named after their causative agent. For example, ''Colletotrichum'' blight is named after the fungus ''
Colletotrichum capsici'', and ''Phytophthora'' blight is named after the water mold ''
Phytophthora parasitica''.
When blights have been particularly vast and consequential in their effects, they have become named historical events, such as the 19th Century
Potato Blight, also known locally from its primary consequence as the ''Great famine'', the
Great Famine of Ireland, and
Highland Potato Famine, and the near extinction of the
Bermuda cedar during the 1940s and 1950s in the event described as ''The Blight'' or ''The Cedar Blight''.
Gallery
File:Chestnut blight.jpg, Chestnut blight
File:Brown Felt Blight.jpg, Brown felt blight
File:Late blight on potato leaf 2.jpg, Potato late blight
File:Fire blight appletree fruit closeup.JPG, Fire blight appletree fruit
File:Three dead Bermuda cedars (Juniperus bermudiana) at Prospect Camp, Bermuda in 2019.jpg, Three dead Bermuda cedars in 2019
References
External links
*Berg A. 1926. Tomato Late Blight and its Relation to Late Blight of Potato.
*Bonn WG, Zwet TVD. Distribution and economic importance of fire blight. Fire blight: the disease and its causative agent, Erwinia amylovora.:37–53.
*Erskine JM. 1973. Characteristics of Erwinia amylovora bacteriophage and its possible role in the epidemiology of fire blight. Canadian Journal of Microbiology; 19(7):837–845.
*Johnson KB, Stockwell VO. 1998. MANAGEMENT OF FIRE BLIGHT: A Case Study in Microbial Ecology. Annual Review of Phytopathology 36:227–248.
*M. N. Schroth, S. V. Thomson, D. C. Hildebrand, W. J. Moller. 1974. Epidemiology and Control of Fire Blight. Annual Review of Phytopathology, 12:1, 389-412.
*Mcmanus PS. 1994. Role of Wind-Driven Rain, Aerosols, and Contaminated Budwood in Incidence and Spatial Pattern of Fire Blight in an Apple Nursery. Plant Disease 78:1059.
*Puławska J, Sobiczewski P. 2011. Phenotypic and genetic diversity of Erwinia amylovora: the causal agent of fire blight. Trees 26:3–12.
*Rico A, Ortiz-Barredo A, Ritter E, Murillo J. 2004. Genetic characterization of Erwinia amylovora strains by amplified fragment length polymorphism. Journal of Applied Microbiology; 96(2):302–310.
*Ritchie DF. 1977. Isolation of Erwinia amylovora Bacteriophage from Aerial Parts of Apple Trees. Phytopathology 77:101.
*Steiner PW. 1996. What We Don’t Know About Fire Blight. Acta Horticulture; (411):3–6.
*Thomas TM. 1992. Severity of Fire Blight on Apple Cultivars and Strains in Michigan. Plant Disease 76:1049.
*Vanneste JL. What is fire blight? Who is Erwinia amylovora? How to control it? Fire blight: the disease and its causative agent, Erwinia amylovora.:1–6.
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