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A wilt disease is any number of
disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
s that affect the vascular system of
plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...
s. Attacks by
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
,
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...
, and
nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
s can cause rapid killing of plants, large
tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
branches or even entire trees. Wilt diseases in woody plants tend to fall into two major categories, those that start with the branches and those that start with the roots. Those that start with the branches most often start with pathogens that feed on the leaves or bark, those that start with the roots start with wounding or direct entry by the pathogen into the roots, some are spread from one plant to another by way of root grafts.
Pathogen 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 g ...
s that cause wilting diseases invade the vascular vessels and cause the
xylem Xylem is one of the two types of transport tissue in vascular plants, the other being phloem. The basic function of xylem is to transport water from roots to stems and leaves, but it also transports nutrients. The word ''xylem'' is derived from ...
to fail to transport water to the foliage, thus causing wilting of stems and leaves.


Wilt diseases

Wilt diseases include:


Bacterial wilt of cucurbits

Bacterial wilt of cucurbits is cause by the bacteria '' Erwinia tracheiphila'', it affects cucumber, squash, muskmelon, pumpkin, gourds; certain varieties of cucumber and squash have different degrees of resistance. Once a plant is infected, the bacteria spread through the xylem vessels from the area of infection to the main stem, and the entire plant wilts and dies. Initial symptoms may include the wilting of single leaves and smaller stems. Infected plants may produce a creamy white bacterial ooze when cut. The bacteria survive winter in the digestive tract of striped cucumber beetles and spotted cucumber beetles. In the spring when the beetles are feeding on susceptible plants, the bacteria, which are contained in the fecal matter of the beetles enters the plant through wounds in the
epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rel ...
. The bacteria need a film of water to facilitate infection. The bacteria can also be transmitted from one plant to another when beetles feed on an infected plant and the bacteria becomes attached to the beetles mouthparts. The bacteria ''
Ralstonia solanacearum ''Ralstonia solanacearum'' is an aerobic non-spore-forming, Gram-negative, plant pathogenic bacterium. ''R. solanacearum'' is soil-borne and motile with a polar flagellar tuft. It colonises the xylem, causing bacterial wilt in a very wide range ...
'' and related species cause bacterial wilt of
banana A banana is an elongated, edible fruit – botanically a berry – produced by several kinds of large herbaceous flowering plants in the genus ''Musa''. In some countries, bananas used for cooking may be called "plantains", disting ...
s and plantains. The same bacteria also cause wilt diseases of potatoes ('' Solanum tuberosum''), tomatoes ('' Solanum lycopersicum''), aubergine (eggplant) ('' Solanum melongena''), banana (''
Musa Musa may refer to: Places *Mūša, a river in Lithuania and Latvia * Musa, Azerbaijan, a village in Yardymli Rayon * Musa, Iran, a village in Ilam Province * Musa, Chaharmahal and Bakhtiari, Iran * Musa, Kerman, Iran * Musa, Bukan, West Azerbaija ...
'' species), geranium (''
Pelargonium ''Pelargonium'' () is a genus of flowering plants that includes about 280 species of perennials, succulents, and shrubs, commonly called geraniums, pelargoniums, or storksbills. ''Geranium'' is also the botanical name and common name of a separa ...
'' species), ginger ('' Zingiber officinale''), tobacco (''
Nicotiana tabacum ''Nicotiana tabacum'', or cultivated tobacco, is an annually grown herbaceous plant of the ''Nicotiana'' genus. The plant is tropical in origin, is commonly grown throughout the world, and is often found in cultivation. It grows to heights be ...
''), sweet peppers (''
Capsicum ''Capsicum'' () is a genus of flowering plants in the nightshade family Solanaceae, native to the Americas, cultivated worldwide for their chili pepper or bell pepper fruit. Etymology and names The generic name may come from Latin , me ...
'' species), olive ('' Olea europea''), and others.


Dutch elm disease

Dutch elm disease Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into America, Europe ...
is caused by the
fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
'' Ophiostoma ulmi'', it affects elm trees.


Elm yellows

Elm yellows sometimes called elm phloem necrosis, affects elm trees and is caused by a
Mycoplasma ''Mycoplasma'' is a genus of bacteria that, like the other members of the class '' Mollicutes'', lack a cell wall around their cell membranes. Peptidoglycan ( murein) is absent. This characteristic makes them naturally resistant to antibioti ...
like organism. It is spread by the white-banded leafhopper.


Mimosa wilt

Mimosa wilt is caused by the fungus '' Fusarium oxysporum''. It enters through the roots and spreads into the vascular system through the tree's sap. As it grows it clogs the vascular tissue leading to yellowing leaves and defoliation.


Oak wilt

Oak wilt is a fungal caused by ''
Bretziella fagacearum Oak wilt is a fungal disease caused by the organism ''Bretziella fagacearum'' that threatens ''Quercus'' spp. The disease is limited to the Midwestern and Eastern United States; first described in the 1940s in the Upper Mississippi River V ...
'', is a disease originating in eastern Russia. It can slowly or quickly kill an
oak tree An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
when the tree reacts to the fungus by plugging its own cambial tissue while attempting to block the spread of the fungus. This plug prevents the cambium vascular tissue from delivering nutrients and water to the rest of the plant, which eventually kills it.
Red oaks The genus ''Quercus'' contains about 500 species, some of which are listed here. The genus, as is the case with many large genera, is divided into subgenera and sections. Traditionally, the genus ''Quercus'' was divided into the two subgenera '' ...
are very susceptible.


Persimmon wilt

Persimmon wilt attacks persimmons and is caused by '' Acromonium diospyri'', a fungus. In the United States it has nearly eliminated persimmons from the central basin of Tennessee. Because of its lethality to persimmons, it was proposed as a biological control agent to eliminate unwanted native persimmons.


Pine wilt

Pine wilt is caused by the North American native pinewood nematode (''
Bursaphelenchus xylophilus ''Bursaphelenchus xylophilus'', commonly known as pine wood nematode or pine wilt nematode (PWN), is a species of nematode that infects trees in the ''Pinus'' genus of coniferous trees and causes the disease pine wilt.indigenous it is not major pathogen of native pine species, but in North America it causes wilt in a few non-native North American pine species. It has been introduced into Japan and China, where it has become a troubling disease of Japanese red pines ('' Pinus densiflora'') and black pines ('' Pinus thunbergii''). Over 46 million cubic meters of trees have been lost alone in Japan over a 50-year period. It is spread among conifers by pine sawyer beetles ('' Monochamus'' spp). The nematodes can reproduce quickly in the sapwood under favorable conditions within susceptible pine species, causing wilting and death, sometimes in only a few weeks. North America lumber products are under export restrictions because of the nematode. In the Midwest United States it has killed many Scots pines ('' Pinus sylvestris''), and this attractive tree is no longer recommended for landscaping uses there.


Stewart's wilt

Stewart's wilt is caused by the bacteria ''Pantoea stewartii'' and affects corn plants especially
sweet corn Sweet corn (''Zea mays'' convar. ''saccharata'' var. ''rugosa''), also called sugar corn and pole corn, is a variety of maize grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring recessive muta ...
. It is a problem in the production of sweet corn in the Northeastern US.


Verticillium wilt

Verticillium wilt Verticillium wilt is a wilt disease affecting over 350 species of eudicot plants. It is caused by six species of ''Verticillium'' fungi: ''V. dahliae'', ''V. albo-atrum'', ''V. longisporum'', ''V. nubilum'', ''V. theobromae'' and ''V. tricor ...
affects over 300
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
of
eudicot The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dico ...
plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...
s caused by one of two species of ''
Verticillium ''Verticillium'' is a genus of fungi in the division Ascomycota, and are an anamorphic form of the family Plectosphaerellaceae. The genus used to include diverse groups comprising saprobes and parasites of higher plants, insects, nematodes, moll ...
'' fungus, ''V. dahliae'' and ''V. albo-atrum''. Many economically important plants are susceptible including
cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor pe ...
,
tomato The tomato is the edible berry of the plant ''Solanum lycopersicum'', commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word ...
es,
potato The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern Uni ...
es,
eggplant Eggplant ( US, Canada), aubergine ( UK, Ireland) or brinjal (Indian subcontinent, Singapore, Malaysia, South Africa) is a plant species in the nightshade family Solanaceae. ''Solanum melongena'' is grown worldwide for its edible fruit. Mo ...
s, peppers and ornamentals, as well as others in natural vegetation communities.


Chilli wilt

Chilli wilt is caused by fungus ''Fusarium oxysporum'' f. sp. ''capsici''. The affected plant dies suddenly as a result of toxins produced by the fungus or by the choking of vascular tissues by the fungal structures.


See also

* Forest pathology


References

{{Reflist Plant pathogens and diseases