Please help improve this article or section by expanding it. Further information might be found on the talk page or at requests for expansion. This article has been tagged since January 2007.

Phytopathology (plant pathology) is the scientific study of plant diseases caused by pathogens (infectious diseases) and environmental conditons (non-infectiousness). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are insects, mites, vertebrate or other pests that affect plant health. Phytopathology also involves the study of the identification, etiology, disease cycle, economic impact, epidemiology, pathosystem genetics and management of plant diseases. Image File history File links Wiki_letter_w. ...

The "Disease Triangle" is a central concept of plant pathology for infectious diseases^[1] . It is based on the principle that disease is the result of an interaction between a host, a pathogen, and environment confition.

Infectious diseases

Fungi

Powdery mildew, a Biotrophic Fungi

Rice blast, a necrotrophic fungi

There are over 10,000 fungal pathogens of plants. The fungal plant pathogens themeselves fall into two major groups, the biotrophs which feed from living plant tissue and the necrotrophs which kill plant cells and then live off the nutrients released. However, many plant pathogens adopt a hybrid lifestyle, initially acting as biotrophs before converting to a nectrophic lifestyle. These are called hemibiotrophs. Image File history File linksMetadata Size of this preview: 800 × 600 pixel Image in higher resolution (2560 × 1920 pixel, file size: 1. ... Image File history File linksMetadata Size of this preview: 800 × 600 pixel Image in higher resolution (2560 × 1920 pixel, file size: 1. ... Powdery mildew Powdery mildew is a fungal disease that affects a wide range of plants. ... Lesions caused by the rice blast fungus, Magnaporthe grisea, on rice plant leaves. ... Lesions caused by the rice blast fungus, Magnaporthe grisea, on rice plant leaves. ... Binomial name Magnaporthe grisea (T.T. Hebert) M.E. Barr Synonyms Magnaporthe grisea, also commonly know as rice blast fungus, is a plant-pathogenic fungus that causes a disease affecting rice, and can also infect a number of other agriculturally important cereals including wheat, rye and barley, causing diseases called... Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... A pathogen (literally birth of pain from the Greek παθογένεια) is a biological agent that can cause disease to its host. ... Nutrients and the body A nutrient is any element or compound necessary for or contributing to an organisms metabolism, growth, or other functioning. ...

The majority of phytopathogenic fungi belong to the Ascomycetes and the Basidiomycetes. Classes Archaeascomycetes Hemiascomycetes Euascomycetes Neolectomycetes Pezizomycotina Pneumocystidomycetes Saccharomycotina Schizosaccharomycetes Taphrinomycetes mitosporic Ascomycota Members of the Division Ascomycota are known as the Sac Fungi and are fungi that produce spores in a distinctive type of microscopic sporangium called an ascus (Greek for a bag or wineskin). This monophyletic grouping was formerly... Classes Subdivision Teliomycotina    Urediniomycetes Subdivision Ustilaginomycotina    Ustilaginomycetes Subdivision Hymenomycotina    Homobasidiomycetes - mushrooms The Division Basidiomycota is a large taxon within the Kingdom Fungi that includes those species that produce spores in a club_shaped structure called a basidium. ...

The fungi reproduce both sexually and asexually via the production of spores. These spores may be spread long distances by air or water, or they may be soil bourne. Many soil bourne spores, normally zoospores and capable of living saprophytically, caring out the first part of their lifecycle in the soil. This article is about sex, meaning the different sexes; male, female, etc. ... Asexuality is a designation or self-designation for people who lack feelings of sexual attraction and/or sexual desire. ... The term spore has several different meanings in biology. ... A zoospore is a motile asexual spore utilizing a flagellum for locomotion. ... A Saprotroph (or saprobe) is an organism that obtains its nutrients from non-living organic matter, usually dead and decaying plant or animal matter, by absorbing soluble organic compounds. ... For the American hard rock band, see Soil (band). ...

Fungal dieases can be controlled through the use of fungicides in agriculture, however new races of fungi often evolve that are resistant to various fungicides. Fungicides are pesticides for destruction or development prevention of fungi. ... This article is about race as an intraspecies classification. ... This article is about biological evolution. ...

Significant fungal plant pathogens

• Ascomycetes
  • Fusarium spp.
  • Thielaviopsis spp. (Causal agents of: canker rot, black root rot, Thielaviopsis root rot)
  • Verticillium spp.
  • Magnaporthe grisea (T.T. Hebert) M.E. Barr; causes blast of rice and gray leaf spot in turfgrasses
• Basidiomycetes
  • Rhizoctonia spp.
  • Phakospora pachyrhizi Sydow; causes Soybean rust
  • Puccinia spp.; causal agents of severe rusts of virtually all cereal grains and cultivated grasses

Fusarium is a large genus of filamentous fungi widely distributed in soil and in association with plants. ... Species Thielaviopsis is a small genus of fungi in the order Microascales. ... It has been suggested that this article or section be merged with Verticillium lecanii. ... Binomial name Magnaporthe grisea (T.T. Hebert) M.E. Barr Synonyms Pyricularia grisea Magnaporthe grisea, also commonly know as rice blast fungus, is a plant-pathogenic fungus that causes a disease affecting rice, and can also infect a number of other agriculturally important cereals including wheat, rye and barley, causing... Species Phakopsora meibromiae Phakopsora pachyrizi Soybean rust, sometimes also called Asian soybean rust, is a disease that affects soybeans and other legumes. ...

Oomycetes

Leaf death caused by the oomycete P. ramorum

The oomycete are fungal like organisms that until recently used to be mistaken for fungi. They include some of the most destructive plant pathogens including the genra Phytopthora which includes the casual agents of potato blight and sudden oak death. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Orders Lagenidiales Leptomitales Peronosporales Pythiales Rhipidiales Saprolegniales Sclerosporales Water moulds or Oomycetes are a group of filamentous protists, physically resembling fungi. ... Orders Lagenidiales Leptomitales Peronosporales Pythiales Rhipidiales Saprolegniales Sclerosporales Water moulds or Oomycetes are a group of filamentous protists, physically resembling fungi. ... Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... Omega is a fictional character from the Dead or Alive video game series, acting as the final boss of Dead or Alive 3. ... Potato blight (Phytophthora infestans) is a serious disease of the potato plant. ... Binomial name Phytophthora ramorum Werres et al. ...

Despite not being closely related to the fungi, the oomyctes have developed very similar infection strategies and so many plant pathologists group them with fungal pathogens.

Significant oomycete plant pathogens

• Pythium spp.
• Phytophthora spp.; including the causal agent of the Irish Potato Famine

A genus of fungi within the phylum Oomycota, class Oomycetes, order Peronosporales, family Pythiaceae, the water mold pythium is known for its role as a plant parasite. ... Species Phytophthora arecae Phytophthora botryosa Phytoohthora cactorum Phytophthora cajani Phytophthora cambivora Phytophthora capsici Phytophthora cinnamomi Phytophthora citricola Phytophthora citrophthora Phytophthora clandestina Phytophthora colocasiae Phytophthora cryptogea Phytophthora drechslera Phytophthora erythroseptica Phytophthora fragariae Phytophthora gonapodyides Phytophthora heveae Phytophthora humicola Phytophthora idaei Phytophthora ilicis Phytophthora infestans Phytophthora inflata Phytophthora iranica Phytophthora katsurae Phytophthora... An 1849 depiction of Bridget ODonnell and her two children during the famine. ...

Bacteria

Crown gall disease caused by Agrobacterium

Most bacteria that are associated with plants are actually saprophytic, and do no harm to the plant itself. However, a small number, around 100 species, are able to cause disease. Bacterial diseases are much more prevalent in sub-tropical and tropical regions of the world. Agrobacterium tumefaciens causes gall fomration on roots. ... Agrobacterium tumefaciens causes gall fomration on roots. ... Species Agrobacterium tumefaciens Agrobacterium rhizogenes Agrobacterium is a genus of bacteria that causes tumors in plants. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... A saprotroph (or saprobe) is an organism that obtains its nutrients from non-living organic matter, usually dead and decaying plant or animal matter, by absorbing soluble organic compounds. ... Subtropical (or semitropical) areas are those adjacent to the tropics, usually roughly defined as the ranges 23. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ...

Most plant pathogenic bacteria are rod shaped (bacilli). In order to be able to colonise the plant they have specific pathogenicity factors. There are 4 main bacterial pathogenicity factors: Orders Bacillales Lactobacillales The term bacilli (singular bacillus) is used to refer to any rod-shaped bacteria. ...

1. Cell Wall Degrading Enzymes - used to break down the plant cell wall in order to release the nutrients inside. Used by pathogens such as Erwinia to cause soft rot. A cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, that provides the cell with structural support, protection, and a filtering mechanism. ... Species Candidatus Erwinia dacicola Erwinia amylovora Erwinia aphidicola Erwinia billingiae Erwinia chrysantum Erwinia mallotivora Erwinia papayae Erwinia persicina Erwinia psidii Erwinia pyrifoliae Erwinia rhapontici Erwinia toletana Erwinia tracheiphila Erwinia is a genus of Enterobacteriaceae bacteria containing mostly plant pathogenic species, for example Erwinia amylovora causes fireblight on crops. ...

2. Toxins. These can be non-host specific, and damage all plants, or host specific and only cause damage on a host plant. For a list of biologically injurious substances, including toxins and other materials, as well as their effects, see poison. ...

3. Phytohormones - for example Agrobacterium changes the level of Auxin to cause tumours. Plant hormones (or plant growth regulators, or PGRs) are internally-secreted chemicals in plants that are used for regulating the plants growth. ... Species Agrobacterium tumefaciens Agrobacterium rhizogenes Agrobacterium is a genus of bacteria that causes tumors in plants. ... IAA appears to be the most active Auxin in plant growth. ...

4. Exopolysaccharides - these are produced by bacteria and block xylem vessels, often leading to the death of the plant. In vascular plants, xylem is one of the two types of transport tissue in plants, phloem being the other one. ...

Bacteria control the production of pathogenicity factors via Quorum sensing. Quorum sensing is the ability of bacteria to communicate and coordinate behavior via signaling molecules. ...

Significant bacterial plant pathogens

• Proteobacteria
  • Xanthomonas spp.
  • Pseudomonas spp.

Species P. aeruginosa P. fluorescens P. putida etc. ...

Phytoplasmas ('Mycoplasma-like organisms') and spiroplasmas

Vitis vinifera with "Ca. Phytoplasma vitis" infection

Phytoplasma and Spiroplasma are a genre of bacteria that lack cell walls, and are related to the mycoplasmas which are human pathogens. Together they are referred to as the mollicutes. They also tend to have smaller genomes than true bacteria. They are normally transmitted by sap-sucking insects, being transferred into the plants phloem where it reproduces. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Binomial name Vitis vinifera L. For thousands of years, the fruit and plant of Vitis vinifera, the European grapevine, have been harvested for both medicinal and nutritional value; its history is intimately entwined with the history of wine. ... Species Candidatus Phytoplasma allocasuarinae Candidatus Phytoplasma asteris Candidatus Phytoplasma australiense Candidatus Phytoplasma castaneae Candidatus Phytoplasma cynodontis Candidatus Phytoplasma japonicum Candidatus Phytoplasma mali Candidatus Phytoplasma morrenia Candidatus Phytoplasma oryzae Candidatus Phytoplasma persicae Candidatus Phytoplasma pini Candidatus Phytoplasma prunorum Candidatus Phytoplasma pyri Candidatus Phytoplasma rhamni Candidatus Phytoplasma spartii Candidatus Phytoplasma trifolii Candidatus... To meet Wikipedias quality standards and make it more accessible, this article may require cleanup. ... Myocoplasmas, the smallest known free-living organisms are able to grow in very simple culture media. ... Orders Mycoplasmatales Entoplasmatales Anaeroplasmatales Acholeplasmatales The Mollicutes are an unusual group of bacteria distinguished by the absence of a cell wall; a cell wall is found in most other groups. ... Genome is also a popular science book by Matt Ridley. ... Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets... In vascular plants, phloem is the living tissue that carries organic nutrients, particularly sucrose, to all parts of the plant where needed. ...

Viruses, viroids and virus-like organisms

Pepper mild mottle virus

There are many types of plant virus, and some are even asymptomatic. Normally plant viruses only cause a loss of yield. Therefore it is not economically viable to try to control them, the exception being when they infect perennial species, such as fruit trees. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Look up pepper in Wiktionary, the free dictionary. ... Plant viruses are viruses affecting plants. ... In medicine, a disease is asymptomatic when it is at a stage where the patient does not experience symptoms. ... Yield may mean: In economics, yield is a measure of the amount of income an investment generates over time (related to return on investment). ... Red Valerian, a perennial plant. ...

Most plant viruses have small, single stranded RNA genomes. These genomes may only encode 3 or 4 proteins: a replicase, a coat protein, a movement protein to allow cell to cell movement and sometimes a protein that allows transmission by a vector. This article or section does not adequately cite its references or sources. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...

Plant viruses must be transmitted from plant to plant by a vector. This is normally an insect, but some fungi, nematodes and protozoa have been shown to be viral vectors. Look up vector in Wiktionary, the free dictionary. ... Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... Classes Adenophora    Subclass Enoplia    Subclass Chromadoria Secernentea    Subclass Rhabditia    Subclass Spiruria    Subclass Diplogasteria The roundworms (Phylum Nematoda) are one of the most common phyla of animals, with over 20,000 different described species. ... Wikisource has an original article from the 1911 Encyclopædia Britannica about: Protozoa Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. ...

Nematodes

Root-knot nematode galls

Nematodes are small, multicelluar wormlike creatures. Many leave freely in the soil, but there are some species which parasitize plant roots. They are mostly a problem in tropical and subtropical regions of the world, where they may infect crops. Root knot nematodes have quite a large host range, whereas cyst nematodes tend to only be able to infect a few species. Nematodes are able to cause radical changes in root cells in order to facilitate their lifestyle. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Larva of root-knot nematode, Meloidogyne incognita, magnified 500X, shown here penetrating a tomato root Root-knot nematodes are plant-parasitic nematodes from the genus Meloigogyne. ... Classes Adenophora    Subclass Enoplia    Subclass Chromadoria Secernentea    Subclass Rhabditia    Subclass Spiruria    Subclass Diplogasteria The roundworms (Phylum Nematoda) are one of the most common phyla of animals, with over 20,000 different described species. ... Roots is: The plural of Root Roots (album) Roots (TV miniseries), a mini-series based on a novel by Alex Haley Roots: The Saga of an American Family, a novel by Alex Haley Roots Canada Ltd. ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... Subtropical (or semitropical) areas are those adjacent to the tropics, usually roughly defined as the ranges 23. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

Protozoa

There are a few examples of plant diseases caused by protozoa. They are transmitted as zoospores which are very durable, and may be able to survive in a resting state in the soil for many years. They have also been shown to transmit plant viruses. Wikisource has an original article from the 1911 Encyclopædia Britannica about: Protozoa Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. ... A zoospore is a motile asexual spore utilizing a flagellum for locomotion. ... Stop editing pages god ...

When the motile zoospores come into contact with a root hair they produce a plasmodium and invade the roots. Interior structure of a trichome. ... Roots is: The plural of Root Roots (album) Roots (TV miniseries), a mini-series based on a novel by Alex Haley Roots: The Saga of an American Family, a novel by Alex Haley Roots Canada Ltd. ...

Parastic plants

Parasitic plants such as mistletoe and dodder are include in the study of phytopathology. Families Santalaceae(Viscaceae) Loranthaceae Mistletoe is the common name for various parasitic plants of the families Santalaceae (in the section of the family formerly separated as Viscaceae) and Loranthaceae. ... Species About 100 species, including: Cuscuta americana Cuscuta applanata Cuscuta approximata Cuscuta attenuata Cuscuta boldinghii Cuscuta brachycalyx Cuscuta californica Cuscuta campestris Cuscuta cassytoides Cuscuta ceanothi Cuscuta cephalanthi Cuscuta compacta Cuscuta coryli Cuscuta corylii Cuscuta cuspidata Cuscuta decipiens Cuscuta dentatasquamata Cuscuta denticulata Cuscuta epilinum Cuscuta epithymum Cuscuta erosa Cuscuta europaea Cuscuta...

Non-Infectious disesaes

Main article: Physiological plant disorders

Significant abiotic disorders can be caused by: It is important to be able to distinguish between plant growth problems that are caused by pathogens, such as a virus or fungus, and those which are caused by non-pathological disorders in the functioning of the plant system, such as poor light, weather damage, water-logging or lack of...

Natural

Drought

Frost damage, and breakage by snow and hail

Flooding and poor drainage

Nutrient deficiency

Salt deposition and other soluble mineral excesses (e.g. gypsum)

Wind (windburn, and breakage by hurricanes and tornados)

Lightning and wildfire (also often man-made)

Man-made (arguably not abiotic, but usually regarded as such)

Soil compaction

Pollution of air and/or soil

Salt from winter road salt application

Herbicide over-application

Poor education and training of people working with plants (e.g. lawnmower damage to trees)

Vandalism

A drought is a period of time when there is not enough water to support agricultural, urban, human, or environmental water needs. ... Frost on black pipes Frost is a solid deposition of water vapor from saturated air. ... Animation of snowcover changing with the seasons Snow is precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. ... This does not adequately cite its references or sources. ... Picture of flooding in Amphoe Sena, Ayutthaya Province, Thailand For other uses, see Flood (disambiguation). ... This article does not cite its references or sources. ... This articles section called Other facts does not adequately cite its references or sources. ... Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O. // Heating gypsum to between 100°C and 150°C (302°F) partially dehydrates the mineral by driving off exactly 75% of the water contained in its chemical structure. ... Wind, tacuinum sanitatis casanatensis (XIV century) Wind is the rough horizontal movement of air (as opposed to an air current) caused by an area of lo pressure and an area of hi pressure near eachother and the wind will blow from the hi pressure point to the lo pressure point... This article is about weather phenomena. ... A tornado in central Oklahoma. ... Double lightning. ... Bitterroot National Forest wildfire A wildfire, also known as a wildland fire, forest fire, vegetation fire, grass fire, brush fire, peat fire (gambut in Indonesia), bushfire (in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources. ... For the American hard rock band, see Soil (band). ... Pollution is the release of environmental contaminants. ... This articles section called Other facts does not adequately cite its references or sources. ... This article or section does not cite its references or sources. ... A caricature of Gustave Courbet taking down a Morris column, published by Le Père Duchêne illustré magazine Vandalism is the conspicuous defacement destruction of a structure or symbol against the will of the owner/governing body. ...

Management

Please help improve this article by expanding this section. Further information might be found on the talk page or at requests for expansion. Please remove this message once the section has been expanded. This article has been tagged since January 2007.

• Quarantine
• Cultural
• Plant resistance
• Chemical
• Biological
• Integrated

Image File history File links Wiki_letter_w. ...

See also

• burl
• Common names of plant diseases
• Stunt
• Pesticide
• Strobilurins
• QoI
• Mycology
• Important publications in phytopathology

This article or section does not adequately cite its references or sources. ... Lists of plant diseases are presented in the following table. ... In botany and agriculture, stunt is term describing a plant disease that results in dwarfing and loss of vigor. ... A cropduster spreading pesticide. ... Strobilurins are a group of chemical compounds used in agriculture as fungicides. ... QoI, or Quinone outside inhibitors are a group of fungicides used in agriculture. ... Mycology (from the Greek mykes, meaning fungus) is the study of fungi, their genetic and biochemical properties, their taxonomy, and their use to humans as a source for medicinals (see penicillin) and food (beer, wine, cheese, edible mushrooms), as well as their dangers, such as poisoning or infection. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

External links

• American Phytopathological Society
• British Society for Plant Pathology
• Plant Health Progress, Online journal of applied plant pathology
• Pacific Northwest Fungi, online mycology journal with papers on fungal plant pathogens