Blight refers to a specific

symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showin ...

affecting plants in response to infection by a

pathogenic In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

organism.

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 ''Phytophthora infestans'' is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by ''Alternaria solani'', is also often called "pot ...

, caused by the

water mold Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the result ...

'' Phytophthora infestans'' (Mont.) de Bary, the disease which led to the

Great Irish Famine The Great Famine ( ga, an Gorta Mór ), also known within Ireland as the Great Hunger or simply the Famine and outside Ireland as the Irish Potato Famine, was a period of starvation and disease in Ireland from 1845 to 1852 that constituted a ...

* Southern corn leaf blight, caused by the fungus ''

Cochliobolus heterostrophus ''Cochliobolus heterostrophus'' is a fungal plant pathogen. It can cause southern corn leaf blight in maize. ''Cochliobolus heterostrophus'' is found in many tropical regions and in the southern part of the US. ''Cochliobolus'', although not ...

'' (Drechs.) Drechs,

anamorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

Bipolaris maydis ''Cochliobolus heterostrophus'' is a fungal plant pathogen. It can cause southern corn leaf blight in maize. ''Cochliobolus heterostrophus'' is found in many tropical regions and in the southern part of the US. ''Cochliobolus'', although not c ...

'' (Nisikado & Miyake) Shoemaker, incited a severe loss of corn in the United States in 1970. *

Chestnut blight The pathogenic fungus ''Cryphonectria parasitica'' (formerly ''Endothia parasitica'') is a member of the Ascomycota (sac fungi). This necrotrophic fungus is native to East Asia and South East Asia and was introduced into Europe and North America ...

, caused by the fungus ''Cryphonectria parasitica'' (Murrill) Barr, has nearly completely eradicated mature

American chestnut The American chestnut (''Castanea dentata'') is a large, fast-growing deciduous tree of the beech family native to eastern North America. As is true of all species in genus Castanea, the American chestnut produces burred fruit with edible nuts. ...

s 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 and also is found in apple and

raspberry The raspberry is the edible fruit of a multitude of plant species in the genus ''Rubus'' of the rose family, most of which are in the subgenus '' Idaeobatus''. The name also applies to these plants themselves. Raspberries are perennial with w ...

, among others. * Bacterial leaf blight of rice, caused by the bacterium '' Xanthomonas oryzae'' (Uyeda & Ishiyama) Dowson. * Bacterial seedling blight of rice (''Oryza sativa''), caused by pathogen ''

Burkholderia plantarii ''Burkholderia plantarii'' is a Gram-negative soil bacterium. Its specific name comes from the Latin ''plantarium'' (seedbed).Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005). Bergey's Manual of Systematic Bacte ...

'' * Early blight of potato and tomato, caused by species of the ubiquitous fungal genus '' Alternaria'' * 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 Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defi ...

'' Pseudocercospora

ulei ''Osteomeles anthyllidifolia'', commonly called ''Ūlei'', ''eluehe'', ''uulei'', Hawaiian rose, or Hawaiian hawthorn, is a species of flowering shrub in the rose family, Rosaceae, that is indigenous to Hawaii (all islands but ''Kahoolawe'' and ...

'', also called ''Microcyclus ulei'', ended the cultivation of the rubber tree (''

Hevea brasiliensis ''Hevea brasiliensis'', the Pará rubber tree, ''sharinga'' tree, seringueira, or most commonly, rubber tree or rubber plant, is a flowering plant belonging to the spurge family Euphorbiaceae Euphorbiaceae, the spurge family, is a large fami ...

'') 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 ''Juniperus bermudiana'' is a species of juniper endemic to Bermuda. This species is most commonly known as Bermuda cedar, but is also referred to as Bermuda juniper (Bermudians refer to it simply as ''cedar''). Historically, this tree formed wo ...

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

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.

External links

* * {{Wiktionary-inline Plant pathogens and diseases Mycology