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11,127,515 | https://en.wikipedia.org/wiki/Arthuriomyces%20peckianus | Arthuriomyces peckianus is a fungal plant pathogen, which causes orange rust on members of the genus Rubus, and various species of berries. It is found in central and eastern North America, and Eurasia.
References
Fungal plant pathogens and diseases
Small fruit diseases
Pucciniales
Fungi described in 1873
Fungi of Asia
Fungi of Europe
Fungi of North America
Fungus species | Arthuriomyces peckianus | [
"Biology"
] | 77 | [
"Fungi",
"Fungus species"
] |
11,127,518 | https://en.wikipedia.org/wiki/Chow%27s%20lemma | Chow's lemma, named after Wei-Liang Chow, is one of the foundational results in algebraic geometry. It roughly says that a proper morphism is fairly close to being a projective morphism. More precisely, a version of it states the following:
If is a scheme that is proper over a noetherian base , then there exists a projective -scheme and a surjective -morphism that induces an isomorphism for some dense open
Proof
The proof here is a standard one.
Reduction to the case of irreducible
We can first reduce to the case where is irreducible. To start, is noetherian since it is of finite type over a noetherian base. Therefore it has finitely many irreducible components , and we claim that for each there is an irreducible proper -scheme so that has set-theoretic image and is an isomorphism on the open dense subset of . To see this, define to be the scheme-theoretic image of the open immersion
Since is set-theoretically noetherian for each , the map is quasi-compact and we may compute this scheme-theoretic image affine-locally on , immediately proving the two claims. If we can produce for each a projective -scheme as in the statement of the theorem, then we can take to be the disjoint union and to be the composition : this map is projective, and an isomorphism over a dense open set of , while is a projective -scheme since it is a finite union of projective -schemes. Since each is proper over , we've completed the reduction to the case irreducible.
can be covered by finitely many quasi-projective -schemes
Next, we will show that can be covered by a finite number of open subsets so that each is quasi-projective over . To do this, we may by quasi-compactness first cover by finitely many affine opens , and then cover the preimage of each in by finitely many affine opens each with a closed immersion in to since is of finite type and therefore quasi-compact. Composing this map with the open immersions and , we see that each is a closed subscheme of an open subscheme of . As is noetherian, every closed subscheme of an open subscheme is also an open subscheme of a closed subscheme, and therefore each is quasi-projective over .
Construction of and
Now suppose is a finite open cover of by quasi-projective -schemes, with an open immersion in to a projective -scheme. Set , which is nonempty as is irreducible. The restrictions of the to define a morphism
so that , where is the canonical injection and is the projection. Letting denote the canonical open immersion, we define , which we claim is an immersion. To see this, note that this morphism can be factored as the graph morphism (which is a closed immersion as is separated) followed by the open immersion ; as is noetherian, we can apply the same logic as before to see that we can swap the order of the open and closed immersions.
Now let be the scheme-theoretic image of , and factor as
where is an open immersion and is a closed immersion. Let and be the canonical projections.
Set
We will show that and satisfy the conclusion of the theorem.
Verification of the claimed properties of and
To show is surjective, we first note that it is proper and therefore closed. As its image contains the dense open set , we see that must be surjective. It is also straightforward to see that induces an isomorphism on : we may just combine the facts that and is an isomorphism on to its image, as factors as the composition of a closed immersion followed by an open immersion . It remains to show that is projective over .
We will do this by showing that is an immersion. We define the following four families of open subschemes:
As the cover , the cover , and we wish to show that the also cover . We will do this by showing that for all . It suffices to show that is equal to as a map of topological spaces. Replacing by its reduction, which has the same underlying topological space, we have that the two morphisms are both extensions of the underlying map of topological space , so by the reduced-to-separated lemma they must be equal as is topologically dense in . Therefore for all and the claim is proven.
The upshot is that the cover , and we can check that is an immersion by checking that is an immersion for all . For this, consider the morphism
Since is separated, the graph morphism is a closed immersion and the graph is a closed subscheme of ; if we show that factors through this graph (where we consider via our observation that is an isomorphism over from earlier), then the map from must also factor through this graph by construction of the scheme-theoretic image. Since the restriction of to is an isomorphism onto , the restriction of to will be an immersion into , and our claim will be proven. Let be the canonical injection ; we have to show that there is a morphism so that . By the definition of the fiber product, it suffices to prove that , or by identifying and , that . But and , so the desired conclusion follows from the definition of and is an immersion. Since is proper, any -morphism out of is closed, and thus is a closed immersion, so is projective.
Additional statements
In the statement of Chow's lemma, if is reduced, irreducible, or integral, we can assume that the same holds for . If both and are irreducible, then is a birational morphism.
References
Bibliography
Theorems in algebraic geometry
Zhou, Weiliang | Chow's lemma | [
"Mathematics"
] | 1,201 | [
"Theorems in algebraic geometry",
"Theorems in geometry"
] |
11,127,521 | https://en.wikipedia.org/wiki/Ascochyta%20tarda | Ascochyta tarda or Phoma tarda is a fungal plant pathogen that causes dieback and leafspot on coffee and was first observed in Ethiopia in 1954 (Stewart, 1957). It poses a potentially serious threat to coffee crops, but climate change may reduce the prevalence of environmental conditions favorable to its spread.
Importance
Die-back is a condition in which a tree or shrub begins to die from the tip of its leaves or roots backwards, owing to disease or an unfavorable environment). Necrosis of both flowers and rosettes is also observed with this pathogen and this can significantly reduce crop yield. Researchers once thought that the pathogen would not be able to infect in regions such as north of the Minas Gerais state and northeast of the Brazilian states, but the prevalence of this disease has then since been reported many times (De C. Alves, M., de Carvalho, L.G., Pozza, E.A., Sanches, L., de S. Maia. J.C., 2011). While Ascochyta tarda does not usually present as an epidemic, it can explode as such if the environmental conditions create enough damage on the leaf for the pathogen to have opportunities to enter the leaf tissue. Cold climate, heavy rain, strong wind, and hail are all aggressive weather conditions that increase probability of infection. The optimal temperature for production of conidia, germination of conidia and growth of mycelia is 25 C for this pathogen. (Lorenzetti, E.R., Pozza, E.A., de Souza, P.E., 2014).
In the 1400s, the coffee plant became popular after people realized it could be roasted. By the 1500s it was popular in Arab coffeehouses and shortly thereafter became a popular beverage in Europe. The popularity of coffee had an impact on the rise of business and made coffeehouses a hub for the exchange of ideas addition to enjoying a cup in the company of another person. Coffee gained its popularity in the United States after the Boston Tea Party of 1773; drinking tea had become unpatriotic. Both the French and American Revolution were said to have been planned in coffeehouses. The coffee being produced during this time was a product of slavery in what is now known as Haiti; in Brazil slavery was legal until 1888 and this the economic benefits encouraged a slash and burn culture in Europe that depleted the nutrients in the soil (Zuraw, 2013). The effects of A. tarda have not yet been felt by coffee drinkers in developed countries, but the potential magnitude of an epidemic of such a fungus can be extrapolated based on the coffee’s role in history. Other diseases such as coffee rust (Hemeilia vastatrix) destroyed coffee plantations in Sri Lanka, making England a tea-drinking country in the 19th century (Keim, 2013).
Hosts and symptoms
Ascochyta tarda is known as a noxious pathogen of Arabian or arabica coffee in Ethiopia, Kenya, and Cameroon and some countries in South-east Asia. Leaf necrosis and die back on young branches are the most apparent symptoms. The necrotic spotting in young leaves expands to form brown leaf lesions largely covering the lamina. Pycnidia are found in the necrotic tissue and tarda refers to the late appearance of septa in conidia and the slow maturing habit of pycnospores (Stewart, 1957). The pycnidia are 70-110 microns in diameter. The mature spores have oval and cylindrical shapes with dimensions of 2-3X9-14 microns and straight septa. Immature spores are oval shaped with dimensions 2-3X 4-9 microns may be predominantly or entirely aseptate (Boerema, G.H., de Gruyter, J., Noordeloos, M.M., Hamers, M.E.C., 2004 & Stewart, 1957).
The primary infection of plants is by airborne ascospores that enter the coffee leaves via the stomata. Primary infection presents as lesions in the coffee leaf; the pycnidia develop in the lesions. Secondary spread of pycnidia occurs via contact and rain dispersal and this leads to more development of pycnidia in newly infected leaves with lesions. The pathogen overwinters as mycelium and pycnidia on crop debris, autumn sown crops and volunteer hosts.
Environment
Ascochyta tarda is a major disease of coffee plants with specific temperature and humidity conditions. The effect has been studied on a broad range of temperatures combined with leaf wetness durations on fungal infection and severity of disease. It was determined that fungus growth, conidial production, and germination were optimal at 22.9, 29.8, and 25.1 degrees respectively in vitro. In vivo, pathogen infection is favored anywhere from 15 to 20 degrees Celsius; this was suggested by the increased germs tube length. Using a disease progress curve, this temperature range with increasing periods on leaf wetness duration increased sporulation in vivo. As low temperatures are favorable, global climate change and temperature increase will decrease the number of areas where this pathogen can thrive (Lorenzetti et al., 2014). Based on studies of the distribution of temperatures in Brazil, the prevalence of phoma leaf spot during its period of greatest risk will decrease in future decades because of climate change (Bucker Moraes W., Cintra de Jesus, W.J, de Azevedo Peixoto, L., Bucker Moraes, W., Morra Coser, S., Cecílio, R.A, 2012). This will also be an issue in Ethiopia where coffee farming is the source of income for approximately 15 million farmers in Ethiopia and as much as 60% of the current growing area can become affected (Moat, J., Williams, J., Baena, S., Wilkinson, T., Gole, T.W., Challa, Z.K., Demissew, S., David, A.P., 2017)
See also
List of Ascochyta species
References
De C. Alves, M., de Carvalho, L.G., Pozza, E.A., Sanches, L., de S. Maia. J.C. (2011). Ecological zoning of soybean rust, coffee rust and banana black sigatoka based on Brazilian climate changes. Procedia Environmental Sciences, 6, 35-49.
Boerema, G.H., de Gruyter, J., Noordeloos, M.M., Hamers, M.E.C. (2004). Phoma Identification Manual: Differentiation of Specific and Infra-specific Taxa in Culture. Location: CABI International North America
Bucker Moraes, W., Cintra de Jesus, W.J, de Azevedo Peixoto, L., Bucker Moraes, W., Morra Coser, S., Cecílio, R.A. (2012) Impact of climate change on the phoma leaf spot of coffee in Brazil. Interciencia, 37, 272-278
Keim, B. (2013, June 11). Disease outbreak threatens the future of coffee.
Lorenzetti, E.R., Pozza, E.A., de Souza, P.E. (2014). Effect of temperature and leaf wetness on Phoma tarda and leaf spot in coffee seedlings. Coffee Science, 1, 1-9.
Moat, J., Williams, J., Baena, S., Wilkinson, T., Gole, T.W., Challa, Z.K., Demissew, S., David, A.P. (2017) Resilience potential of the Ethiopian coffee sector under climate change. Nature: Plants, 3, 17081
Zuraw, L. (2013, April 14). How Coffee Influenced The Course of History.
tarda
Fungi described in 1957
Fungi of Africa
Fungal plant pathogens and diseases
Coffee diseases
Fungus species | Ascochyta tarda | [
"Biology"
] | 1,693 | [
"Fungi",
"Fungus species"
] |
11,127,532 | https://en.wikipedia.org/wiki/Ascochyta%20tritici | Ascochyta tritici is a fungal plant pathogen that causes Ascochyta leaf spot on barley, wheat and maize.
See also
List of Ascochyta species
References
tritici
Fungal plant pathogens and diseases
Barley diseases
Wheat diseases
Maize diseases
Fungus species | Ascochyta tritici | [
"Biology"
] | 56 | [
"Fungi",
"Fungus species"
] |
11,127,545 | https://en.wikipedia.org/wiki/Microdochium%20bolleyi | Microdochium bolleyi is a fungal plant pathogen that causes root rot in flax and wheat.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Wheat diseases
Xylariales
Fungus species
Fungi described in 1957 | Microdochium bolleyi | [
"Biology"
] | 54 | [
"Fungi",
"Fungus species"
] |
11,127,553 | https://en.wikipedia.org/wiki/Aureobasidium%20pullulans | Aureobasidium pullulans is a ubiquitous and generalistic black, yeast-like fungus that can be found in different environments (e.g. soil, water, air and limestone). It is well known as a naturally occurring epiphyte or endophyte of a wide range of plant species (e.g. apple, grape, cucumber, green beans, cabbage) without causing any symptoms of disease. A. pullulans has a high importance in biotechnology for the production of different enzymes, siderophores and pullulan. Furthermore, A. pullulans is used in biological control of plant diseases, especially storage diseases.
Chronic human exposure to A. pullulans via humidifiers or air conditioners can lead to hypersensitivity pneumonitis (extrinsic allergic alveolitis) or "humidifier lung". This condition is characterized acutely by dyspnea, cough, fever, chest infiltrates, and acute inflammatory reaction. The condition can also be chronic, and lymphocyte-mediated. The chronic condition is characterized radiographically by reticulonodular infiltrates in the lung, with apical sparing. The strains causing infections in humans were reclassified to A. melanogenum.
A. pullulans can be cultivated on potato dextrose agar, where it produces smooth, faint pink, yeast-like colonies covered with a slimy mass of spores. Older colonies change to black due to chlamydospore production. Primary conidia are hyaline, smooth, ellipsoidal, one-celled, and variable in shape and size; secondary conidia are smaller. Conidiophores are undifferentiated, intercalary or terminal, or arising as short lateral branches. Endoconidia are produced in an intercalary cell and released into a neighboring empty cell. Hyphae are hyaline, smooth, and thinwalled, with transverse septa. The fungus grows at 10–35 °C with optimum growth at 30 °C.
A. pullulans is notable for its phenotypic plasticity. Colony morphology may be affected by carbon source, colony age, temperature, light and substrate, with colonies ranging from homogeneous to sectored, yeast-like to filamentous growth, and from small to large. These changes, potentially influenced by epigenetic factors, and the particular developmental sequences that the colonies proceed through may be observed with the naked eye. Besides these morphological plasticity A. pullulans is also adaptable to various stressful conditions: hypersaline, acidic and alkaline, cold, and oligotrophic. Therefore, it is considered to be polyextremotolerant.
The morphology-based taxonomy of the species is complicated by the large morphological variability between strains and even within a single strain. Based on molecular analyses, four varieties of the species A. pullulans were recognised: var. pullulans from substrates with low water activity and the phyllosphere and a variety of other habitats; var. melanogenum from aquatic habitats; var. subglaciale from glacial habitats; and var. namibiae, which was described on the basis of only one strain isolated from dolomitic marble in Namibia. However, when the genome sequences of these varieties became available, the differences between them were considered as too large to be accommodated in a single species. Therefore, the varieties were reclassified as new species: A. pullulans, A. melanogenum, A. subglaciale, and A. namibiae.
The genome of A. pullulans s. str. contains large numbers of genes of gene families that can be linked to the nutritional versatility of the species and its stress tolerance. The genome also contains a homothallic mating-type locus. Further genome sequencing of fifty A. pullulans s. str. strains showed that the population of the species is homogeneous, with high levels of recombination and good dispersal. The species A. pullulans was thus recognised as a true generalist, able to inhabit a wide variety of habitats with no specialization to any of these habitats at the genomic level. Despite the presence in the genome of a putative mating locus, and the observation of high recombination rates, no sexual cycle has yet been reported in this organism.
Due to the relatively recent redefinition of the species, most published work does not yet distinguish between the new species belonging to the previously recognised A. pullulans species complex. It is therefore not clear to what extent this knowledge is valid for A. pullulans s. str. and what should be attributed to the three new species.
See also
Aureobasidium melanogenum
Aureobasidium namibiae
Aureobasidium subglaciale
Yeast in winemaking
References
Further reading
Themis J. Michailides.
External links
Genome Page on Mycocosm
Fungi described in 1884
Yeasts
Dothideales
Nepenthes infauna
Epiphytes
Fungal plant pathogens and diseases
Apple tree diseases
Fungal grape diseases
Vegetable diseases
Fungus species | Aureobasidium pullulans | [
"Biology"
] | 1,074 | [
"Yeasts",
"Fungi",
"Fungus species"
] |
11,127,559 | https://en.wikipedia.org/wiki/Cochliobolus%20spicifer | Cochliobolus spicifer is a fungal plant pathogen.
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Cochliobolus
Fungi described in 1964
Fungus species | Cochliobolus spicifer | [
"Biology"
] | 44 | [
"Fungi",
"Fungus species"
] |
11,127,570 | https://en.wikipedia.org/wiki/Cephalosporium%20gramineum | Cephalosporium gramineum syn. Hymenula cerealis is a plant pathogen that causes cephalosporium stripe of wheat and other grasses. It was first reported in Japan in 1930. The disease can cause yield losses of up to 50% by causing death of tillers and reducing seed production and seed size. The disease causes broad yellow or brown stripes along the length of the leaf and discolouration of the leaf veins. The fungus spreads through the soil, and enters the plant through wounds in its roots. Early planting of winter wheat when the soil is warm gives a greater root system more subject to root breakage when the soil heaves affording more infection sites. Phosphate fertilizer and high moisture further exacerbate this condition. The symptoms are caused by the fungus invading the plants' vascular tissue. The fungus also produces a toxin which causes stunting of the plant and interferes with development. A glucopolysaccharide also appears to inhibit fluid movement in wheat.
Very little natural resistance to the disease is seen in wheat. Control measures include crop rotation for 2–3 years in areas where the disease has become a particular problem. Currently, no options exist for controlling the disease through the use of fungicides.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Wheat diseases
Enigmatic Ascomycota taxa
Taxa named by Benjamin Matlack Everhart
Fungi described in 1894
Fungus species | Cephalosporium gramineum | [
"Biology"
] | 297 | [
"Fungi",
"Fungus species"
] |
11,127,582 | https://en.wikipedia.org/wiki/Ceratobasidium%20cereale | Ceratobasidium cereale is a plant pathogen.
References
Fungal plant pathogens and diseases
Cantharellales
Fungi described in 1984
Fungus species | Ceratobasidium cereale | [
"Biology"
] | 31 | [
"Fungi",
"Fungus species"
] |
11,127,586 | https://en.wikipedia.org/wiki/Mycosphaerella%20coffeicola | Mycosphaerella coffeicola is a sexually reproducing fungal plant pathogen. It is most commonly referred to as the asexual organism Cercospora coffeicola.
Host and symptoms
There are 40 species in the genus Coffea (family Rubiaceae) that are susceptible to the disease caused by M. coffeicola, but only a few that are commercially relevant. Arabica coffee (Coffea arabica L.) is the most significant of the susceptible species, affecting 70% of the world's coffee production. Coffea arabica ranges in growth habit from a shrub to a small tree and has ovate, shiny, pointed leaves, with clustered white flowers. The fruits begin as green berries which ripen to a deep red color. These are often called the coffee "cherries". Each fruit contains two seeds (i.e. coffee beans) in a drupe.
Symptoms of M. coffeicola vary depending on the plant organ affected. These differing symptoms help explain the various common names for the disease: Cercospora "Leaf Spot" and Cercospora "Berry Blotch" (Cercospora is reference to the deuteromycete stage). On leaves, lesions begin as chlorotic (yellow) spots that expand to become deep brown and necrotic on the upper leaf surface. These spots often have a discolored, light center where sporulation can occur, and many have a yellow "halo" around the margins. This halo is caused by the toxin cercosporin, produced by Cercospora species. Not all lesions have distinct edges or a halo, however, and some occur in concentric rings. In general, lesions of this species are able to fuse, and can form large irregular areas of necrotic tissue. Leaves may drop in extreme cases. Fruit symptoms typically appear 90 days after flowering. On green berries, this includes irregularly shaped brown, sunken lesions that are surrounded by a purple halo. Infected red cherries also have large, dark areas of sunken flesh. At this stage, fruit is susceptible to attack by opportunistic bacteria and fungi (such as Colletotrichum gloeosporioides), though symptoms from these organisms should not be falsely attributed to M. coffeicola.
Environment
Disease is often affected by the environment and the changing conditions. M. coffeicola is a tropically adapted pathogen due to its host narrow geographical range around the equator. Favorable environmental conditions around the equator are warm and humid wet seasons followed by a warm and dry season. The highest disease pressure occurs when the temperature is and continuous environmental wetness for 36–72 hours. Mornings where temperatures reach the dew point (>98% humidity) are perfect conditions for conidia to disperse. A nitrogen-deficient plant as well as a plant with excess nitrogen favors disease prevalence, making well-timed fertilizer applications important. Other factors that can increase disease incidence are insufficient shade, herbicide injury, plant stress, and other diseases caused by nematodes. The reason for increased disease is that stressed plants are more susceptible.
Disease cycle
Conidia of Mycosphaerella coffeicola are produced year-round and enter the coffee plant through stomata on the underside of a leaf, or through the epidermal cuticle on the upper leaf surface. Inter- and intracellular hyphal growth creates vegetative lesions where sporulation occurs. Conidiophores and conidia are formed here, and then dispersed by wind or by water. Conidiophores emerge in bundles of 3–30 and are often septate and branched. Conidia are elongated, multiseptate, and either straight or slightly curved. They appear glassy and have a conspicuous hilum. The spores can splash from one leaf to another, or onto flowers and berries causing secondary infections. The continuous production of conidia guarantees infection at multiple stages of plant development (in leaves, flowers, and fruit). The fungus can overwinter (i.e. survive a dry season) as conidia in dropped, infected leaves for up to two months. Once humid conditions return, conidia infect new plants or plant parts.
Management
Prevention is the most effective method of managing M. coffeicola. Risk factors for this pathogen include: prolonged (24–72 hours) humid environment, poor soil nutrition, and plant stress caused by increased planting density, herbicide injury, weeds, drought, and over irrigation. To manage humidity a farmer can prune to allow for air circulation and ensure the soil has proper drainage. In order to maintain proper plant nutrition, soil testing and a fertilization regiment are essential for combating this pathogen. Plant symptoms such as chlorosis, leaf curling, and bronzing along the edges of leaves can be used to diagnose specific nutrient deficiencies. For example, if a plant has leaves bronzed along edges, cupped down-ward; new leaves dead; eventual die back of shoot tips, then it is likely the plant has a calcium deficiency. To reduce plant stress, a farmer can use herbicides to combat weeds but must be careful not to damage the plant in process. Also to minimize competition between adjacent crops, it is important to properly space coffee plants in 8 ft. by 8 ft. areas. Stress can further be minimized if post and pre-harvest damage by machinery or laborers is avoided. To avoid wilting stress plants should be properly irrigated . However, if a crop already has M. coffeicola, copper fungicide is effective. In Hawaii, farmers often spray tri-annually, using 1.5–6 lbs of fungicide per 50–100 gallons water, containing 30–80% copper hydroxide. "Sprays should coincide with dry weather and calm winds. Three spray applications per season should suffice (occurring approximately once per month), beginning at flowering. Thorough coverage of the plant canopy is very important. Large farms in Hawai‘i utilize tractor-mounted mist blowers."
Importance
Coffee is the 15th most valuable traded commodity in the world. There are approximately 25 million farmers and coffee workers in over 50 countries involved in producing coffee around the world. M. coffeicola is present throughout the world and can account for yield losses as high as 15% annually. In parts of Puerto Rico nearly 50% of cultivated coffee acres are affected by this disease, resulting in yield losses around 15%. Due to the fact Mycosphaerella coffeicola proliferates in a sustained warm, humid environment, M. coffeicola is most prevalent in the low-elevation Central American farms where high daily average temperatures and high humidity are observed. Literature suggests that M. coffeicola is not a significant problem in Ethiopia and Uganda, Africa's top coffee-producing countries. Conversely, M. coffeicola is common in Hawaii but not economically important due to proper management practices and the environment does not have the prolonged humid environment necessary for proliferation.
Pathogenesis
The genus Cercospora shows a wide variety of infection processes; even a single species can show different patterns on different hosts. One unifying factor is that species of Cercospora produce a photoactivated perylenequinone called cercosporin. In the dark, cercosporin lacks toxicity but when exposed to light, it is converted into a toxic form of activated oxygen. This damages membrane lipids resulting in cell death and nutrient leakage. The pathogen uses the leaked nutrients as an energy source. M. coffeicola is a wind-borne pathogen that utilizes cercosporin to infect both the berries and leaves of the coffee plant. Lesions on infected berries produce conidia 17 days after inoculation. If on the leaves, conidia are produced 38 days after inoculation.
After the spores land on the plant surface, one to several germ tubes are produced. The germ tubes aggregate and penetrate the plant via the stomata or cracks in the leaf surface. The fungus can survive 36 days as conidia and 218 days as mycelium, which suggests that M. coffeicola overwinters in lesions. On berries, the lesions are tan and sunken and can occur while the berry is green. As the lesion matures, it becomes deeply depressed with an ashy center and may penetrate down to the coffee bean to affect the bean quality and taste. If on mature fruits, the lesion measures 1–4 mm in diameter.
There is conflicting information if fungal strains on berries can infect leaves and vice versa.
See also
List of Mycosphaerella species
References
Fungi described in 1880
Fungi of Africa
Fungi of Central America
Fungi of North America
Fungal plant pathogens and diseases
coffeicola
Fungus species | Mycosphaerella coffeicola | [
"Biology"
] | 1,810 | [
"Fungi",
"Fungus species"
] |
11,127,599 | https://en.wikipedia.org/wiki/Mycosphaerella%20gossypina | Mycosphaerella gossypina is a plant pathogen.
See also
List of Mycosphaerella species
References
gossypina
Fungal plant pathogens and diseases
Fungi described in 1883
Fungus species | Mycosphaerella gossypina | [
"Biology"
] | 43 | [
"Fungi",
"Fungus species"
] |
11,127,600 | https://en.wikipedia.org/wiki/Mycosphaerella%20confusa | Mycosphaerella confusa is a fungal plant pathogen.
See also
List of Mycosphaerella species
References
confusa
Fungal plant pathogens and diseases
Fungi described in 1876
Fungus species | Mycosphaerella confusa | [
"Biology"
] | 42 | [
"Fungi",
"Fungus species"
] |
11,127,604 | https://en.wikipedia.org/wiki/Cercosporella%20rubi | Cercosporella rubi is a plant pathogenic fungus which causes blackberry rosette, a disease that is also known as double blossom or witches' broom of blackberry. In infected plants, the symptoms that C. rubi causes are double blossoms as well as witches' brooms. Diseased canes do not produce fruit, and as a result, this pathogen poses one of the largest threats to commercial blackberry production. The disease is most prevalent in the southeast United States.
Hosts and Range
The hosts of C. rubi are limited to the genus Rubus, which encompasses blackberries (both erect and trailing varieties), raspberries, dewberries, and boysenberries. Blackberries are the most common host of this disease, though it's possible for boysenberries to serve as hosts as well. Blackberry cultivars with thorns are much more susceptible to rosette than thornless varieties.
In the United States, rosette disease of blackberry is commonly found in the southeast parts of the country encompassed by New Jersey, Illinois, and Texas. The disease spreads to new areas through infected nursery stock or the dispersion of wind borne spores.
Life Cycle
The life cycle of C. rubi follows the biennial life cycle of blackberry canes. The first-year non-flowering canes, known as primocanes, are infected by conidia that are dispersed by C. rubi fruiting bodies. These fungal bodies lie within the infected flowers of second-year canes, which are known as floricanes. C. rubi overwinters within axillary buds of the primocanes until the springtime when they become floricanes and flower. At this stage, conidia are released, they infect new primocanes, and the cycle begins anew.
Control
Preventative Control
The most reliable way to control C. rubi and prevent the spread of rosette disease is to use disease-free planting stock and plant resistant cultivars. Root stocks or cutting from roots can be used, as the disease is not systemic. The spread of C. rubi can also be mitigated by removing wild blackberries or dewberries from an area prior to planting crop blackberries. This is because these wild plants can also serve as hosts for C. rubi, and if left alone will grow vigorously and spread the disease to cultivated blackberry plants in the area.
Sanitation & Pruning
Low to Moderate Infections
Plants with low to moderate levels of C. rubi infection should be pruned to remove infected biomass. Diseased canes can be identified by the presence of witches' brooms or elongated flower buds that are a deeper pink color than healthy flowers. Ideally, the biomass should be removed before the blossoms open to prevent further spread of the fungus. Once removed, the infected biomass should be destroyed with a controlled burn to prevent the spread of the fungus post-pruning.
Severe Infections
In the case of severely infected plants, one can cut both the primocanes and floricanes down to the ground immediately after harvest. This removes infected tissue and fungal bodies. This practice works best for blackberry varieties that grow vigorously as opposed to those that are slower growing, as it heavily reduces fruit production.
Fungicides
Fungicides in the strobilurin group, such as pyraclostrobin or azoxystrobin, as well as those in the anilinopyrimidine group can control C. rubi. For fungicides to work properly, they must be applied when infected flowers are open. Therefore, they should be applied from the time when buds start to swell up until all flowers are spent.
References
Fungal plant pathogens and diseases
Small fruit diseases
Mycosphaerellaceae
Fungi described in 1937
Fungus species | Cercosporella rubi | [
"Biology"
] | 774 | [
"Fungi",
"Fungus species"
] |
11,127,608 | https://en.wikipedia.org/wiki/Graphyllium%20pentamerum | Graphyllium pentamerum is a species of fungus in the family Hysteriaceae. It is a plant pathogen infecting wheat.
References
Hysteriales
Fungi described in 1872
Fungal plant pathogens and diseases
Wheat diseases
Fungus species | Graphyllium pentamerum | [
"Biology"
] | 47 | [
"Fungi",
"Fungus species"
] |
11,127,611 | https://en.wikipedia.org/wiki/Discostroma%20corticola | Discostroma corticola is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Xylariales
Fungi described in 1976
Fungus species | Discostroma corticola | [
"Biology"
] | 41 | [
"Fungi",
"Fungus species"
] |
11,127,616 | https://en.wikipedia.org/wiki/Colletotrichum%20kahawae | Colletotrichum kahawae is a fungal plant pathogen that causes coffee berry disease (CBD) on Coffea arabica crops. The pathogen is an ascomycete that reproduces asexually. The asexual spores (conidia) are stored within acervuli. This disease is considered to be one of the major factors hampering C.arabica production in the African continent, which represents the current geographic range of the fungus. Coffee berry disease causes dark necrosis in spots and causes the green berries of the coffee to drop prematurely. High humidity, relatively warm temperatures, and high altitude are ideal for disease formation. Given the severity of the disease and the lack of effective control measures, there is great concern that the fungus may spread to other coffee producing continents, such as South America, which could have catastrophic consequences.
Taxonomy
Until recently, the taxonomic description and position of C. kahawae was a subject of great confusion. From the range of Colletotrichum spp. that are isolated from coffee plants, four groups were initially described based on their morphological traits: CCM (C. coffeanum mycelial), CCA (C. coffeanum acervuli), CCP (C. coffeanum pink) and the Coffee berry disease (CBD) strain. The three former groups were later recognized as C. gloeosporioides Penz (CCM and CCA) and C. acutatum Simmonds (CCP), and proved to be non-pathogenic in green coffee berries. Only the fourth group was able to infect both wounded and unwounded green berries and was formerly referred to as C. coffeanum. However, C. coffeanum was described in 1901 based on Colletotrichum isolated from coffee in Brazil, where CBD does not exist, and was probably synonymous with C. gloeosporioides, which occurs as a saprophyte or weak pathogen of ripe berries and damaged coffee tissue worldwide. Several authors attempted to emend this anomaly but it was not until 1993 that Waller and Bridge described C. kahawae as the causal agent of CBD and as a distinct species based on morphological, cultural and biochemical characters and more recently on multi-locus datasets. According to the American Phytopathological Society, C. kahawae is also a causal agent of the bacterial disease Brown Blight
Host and symptoms
Areca catechu (betelnut palm), Citrus reticulata (mandarin), Coffea arabica (arabica coffee), Coffea canephora (robusta coffee), Coffea liberica (Liberian coffee tree), Cyphomandra betacea (tree tomato), Eruca vesicaria (purple-vein rocket), Liquidambar styraciflua (Sweet gum), and Malus domestica (apple) are all hosts of C. kahawae. Infection can occur on all stages of the plant, from unopened inflorescences to ripe berries and occasionally leaves. The defining characteristic of C. kahawae is its ability to infect green berries; between 4–14 weeks after flowering it is most susceptible. There are two distinct symptoms of berry infections termed "active" and "scab" lesions. The common symptoms of the active lesions are dark brown, slightly sunken spots that begin small and eventually enlarges in area consuming the entire berry to become black. Consequently, the pulp becomes brown, hard, and brittle while the surface of the berry remains smooth (except for the fungal fruiting structures). Under humid conditions, the fruiting structures on the lesions may produce pink spore masses that become white with age. The scab lesions can be found on both young and mature berries in which the lesions are corky, pale tan in color, and slightly sunken. These lesions form stagnantly until the fruit begins to ripen creating a more beneficial environment for the fungus to grow. Secondary inoculum may be produced by the pathogen as seen by concentric rings that are surrounded by emerging black acervuli within the lesion. The active lesions will result in the arrest of berry development depending on favorable weather conditions. This process will in turn result in berry mummification on the branch, and when the berry begins to ripen anthracnose will develop causing the bean to then become infected.
Disease cycle and epidemiology
The polycyclic disease cycle of Colletotrichum kahawae is heavily dependent on rain/water for conidial production, dispersion, germination and infection. The timing of infection is regulated by the seasons and rainfall. Coffee growing regions of Africa receive two seasons of rain: long rains and short rains with relatively dry weather in between. The long rains are what induce initial flowering and therefore, initial infection. Short rains induce secondary flowering, but do not contribute to the severe infections of CBD. C. kahawae is an ascomycete that produces conidia from simple hyphae for which its perfect state is still unknown. Mummified berries and twig bark are considered to be primary sources of inoculum for the disease. The spores are covered in a gelatinous coat which expands under wet conditions to facilitate in spore dispersal during rain. Spore movement is downward in tree canopies due to movement being controlled by water films. This characteristic is a reason why coffee crowns are important sources of inoculum in coffee berry disease (CBD). Spores are laterally dispersed between trees and branches by wind and rain, yet localized, downward movement is the prototypical inoculum movement. Common vectors of long and medium-distance dispersal are: Birds, Coffee harvesters, and sometimes insects.
Colletotrichum conidium germination can occur 24 hours after contact with the host plant tissue. Then follows elongation of the germ tube, whose apical section differentiates into a melanised appressorium. This structure will then function to penetrate the plant cell cuticle directly via turgor pressure. C. kahawae is a hemibiotroph that exhibits a transient post-penetrative asymptomatic biotroph phase followed by a necrotrophic phase in which symptoms of CBD are seen. During the biotroph phase, the pathogen invades the host cells without killing them. The fungus then feeds on the living tissue for a period of 48–72 hours post inoculation depending on the isolate aggressiveness. The second phase of feeding, the nectrotrophic phase, involves the increased activity of cell-wall degrading enzymes to function in C. kahawae pathogenicity. The colonization is associated with severe cell wall alterations and death of the host protoplast.
Origin and distribution
The first report of coffee berry disease caused Colletotrichum kahawae dates back to 1922 in western Kenya when it led to the destruction and abandon of C. arabica plantations in some regions. Soon after, the fungus has quickly spread throughout most of the African continent, being reported in Angola (1930), Democratic Republic of the Congo (1938), Cameroon (1955), Tanzania (1964), Ethiopia (1971), Malawi and Zimbabwe (1985), and eventually most of the Arabic coffee areas in the continent were affected. Until 2018, the disease remained constrained to the African continent, but reported occurrence now includes Colombia and Cuba in the Americas with Hainan island in Asia.
Environment
CBD has a high incidence of occurring in highland regions and there is only disease beyond 1000 meters above sea level (m.a.s.l.) (altitude to which C. arabica is grown). The disease is highly dependent upon climatic factors: humidity, rainfall, and temperature. As stated above, rainfall is necessary for spore germination and dispersal for C. kahawae. Temperatures of are optimal for germination and mycelial growth. Appressorium formation occurs at the same temperatures and at a high relative humidity.
Management
Current methods for control of coffee berry disease are resistance and fungicide applications. A study found that there are major genes on three different loci controlling resistance to CBD. The major cultivars being grown with high resistance to the disease are C. arabica L. var. Rume Sudan and the spontaneous hybrid Hibrido de Timor (HdT). Plants bred from these varieties (Catimor, Ruiru 11, etc.) are being used to develop better resistance through gene stacking approaches. This process is made more difficult when a variety that has been bred for high resistance develops undesirable traits ( low yield, poor bean profile, etc.) for commercially produced products, as seen in the Catimor variety. Coffee growing regions outside of Africa are in the process of developing new coffee varieties or increasing the level of resistance in current commercial varieties to CBD as a precaution to the spread of the pathogen. This process is undertaken using artificial methods of screening to detect CBD in young coffee crops (commonly seed hypocotyls) to speed up the resistance screening process.
Fungicide applications are the primary management tactic carried out. Different copper-based fungicides, organic fungicides, as well as mixtures of the two are recommended to control CBD. Copper-based fungicides are used the most due to their low-cost compared to organic fungicides; yet they become expensive when disease intensity requires 7-8 applications per year. This process can become laborious, expensive, and destructive to the soil ecology. CBD's chemical control may account for up to 45% of the annual cost of production in some fields. Despite such elaborate control measures, losses as high as 50% of the potential crop may still occur under unfavorable weather conditions.
Cultural practices are suggested to be interwoven in conventional management tactics. These methods include pruning infected branches, destruction of infected material, removal of mummified berries, minimizing optimal microclimatic conditions for pathogen growth, and the use of competitive and antagonistic microorganisms in the plant phyllosphere. Colletotrichum kahawae has been shown to produce less disease when shaded by fruit trees, as the fruit trees prevent rainfall from falling on berries, thus preventing dispersal of conidia. It has also been noted that the use of the fungus Fusarium stilboides Wollenv and Epicoccum nigrum Link and some yeasts could function in limiting CBD progression. A recent publication has identified and characterized Streptomyces species with strong antagonism towards C. kahwae. These potential biocontrol tactics would then need to be balanced with the use of fungicides due to observations that repeated fungicide applications increased CBD by removal of fungal biocontrols.
Impact
There are limited control options once CBD has established on a host. The use of fungicides on susceptible varieties can be extremely costly especially as the disease progresses. In Kenya, it is estimated that it would cost $500 per hectare to manage CBD with chemical control. Because coffee berry disease can become very severe and there is a lack of effective control measures, there is great concern that the fungus may spread to coffee growing areas in other continents, such as South America, which could have catastrophic consequences. Currently, however, the disease is only prevalent in areas Africa at high elevations and with high relative humidity. The disease has been recorded to cause up to 80% yield loss.
References
kahawae
Fungal plant pathogens and diseases
Coffee diseases
Fungi described in 1993
Fungus species | Colletotrichum kahawae | [
"Biology"
] | 2,404 | [
"Fungi",
"Fungus species"
] |
11,127,621 | https://en.wikipedia.org/wiki/Colletotrichum%20gossypii | Colletotrichum gossypii is a plant pathogen. This fungus is affiliated with cotton plants where it causes anthracnose. Its reproduction in the plants is asexual. The conidia have only one nucleus. Before conidia germination fusion by mean of conidial anastomosis tube could happen. The conidia could germinate in media plates.
References
gossypii
Fungi described in 1981
Fungal plant pathogens and diseases
Cotton diseases
Fungus species | Colletotrichum gossypii | [
"Biology"
] | 101 | [
"Fungi",
"Fungus species"
] |
11,127,629 | https://en.wikipedia.org/wiki/Gymnopus%20dryophilus | Gymnopus dryophilus is a mushroom commonly found in temperate woodlands of Europe and North America. It is generally saprophytic, but occasionally also attacks living wood. It belongs to section Levipedes of the genus, being characterized by a smooth stem having no hairs at the base (in contrast to section Vestipedes). Until recently it was most frequently known as Collybia dryophila.
Description
The cap is in diameter, convex, and reddish-brown to ochre (fading to tan with dryness); they become more irregular in shape with age. The gills, which are only thinly attached to the stem (detaching with age), are whitish and crowded. The spore powder is white; the buff spores do not react in Melzer's reagent. The bald stem ranges from long by 3–6 mm in diameter, sometimes thicker at the base. The taste is palatable.
Microscopically the spores are 6×3 μm in size and slightly tear-shaped, there are lobed club-shaped cystidia (15–50 μm × 2–6 μm), and the hyphae on the cap cuticle can also have lobes.
It is contended that G. dryophilus in fact consists of a complex of different species and that several new species (including G. brunneolus, G. earleae and G. subsulphureus) should be split off from it. However these species are not generally recognized at present.
One similar species is Rhodocollybia butyracea, which has a pinkish spore deposit, and some of the spores turn reddish-brown in Melzer's reagent.
The species may carry the parasite Syzygospora mycetophila, which causes pale growths on the mushroom surface.
Distribution and habitat
This fungus is very common in northern hemisphere temperate woodlands (so much so that it is sometimes considered a "weed" mushroom). It fruits from April to December and is often seen when there are few other fungi in evidence. Although the Greek epithet dryophilus means "lover of oak trees", it is also found with other broad-leaved trees and with conifers.
Grows in arcs and fairy rings in oak and pine woods, or as clusters on wood chip mulch from May to October.
Edibility
Gymnopus dryophilus contains toxins which may cause severe gastrointestinal issues. However, it has been listed as edible by some sources, though not worthwhile. It is recommended not to eat the stem, which is tough.
It has been found to contain anti-inflammatory beta-glucans.
The mushroom has a sweet nutty flavor and should not be eaten in contaminated places like industrial or near roads due to its capacity to take up mercury. It is edible but may cause gastrointestinal issues in some people.
References
External links
Index Fungorum
USDA ARS Fungal Database
“Gymnopus dryophilus” by Robert Sasata, Healing-Mushrooms.net, December, 2007.
Kuo, M. (2008, May) Gymnopus dryophilus at the MushroomExpert.Com Web site
Fungal plant pathogens and diseases
Fungi of Europe
Omphalotaceae
Taxa named by Jean Baptiste François Pierre Bulliard
Fungus species | Gymnopus dryophilus | [
"Biology"
] | 686 | [
"Fungi",
"Fungus species"
] |
11,127,650 | https://en.wikipedia.org/wiki/Erythricium%20salmonicolor | Erythricium salmonicolor is a species of fungus in the family Corticiaceae. Basidiocarps are effused, corticioid, smooth, and pinkish and grow on wood. The fungus is a commercially significant plant pathogen which has become a serious problem, especially in Brazil. Erythricium salmonicolor causes Pink Disease, most commonly in Citrus, although E. salmonicolor has a wide host range including rubber and cacao trees. Pink Disease causes branch and stem die-back due to canker formation. The cankers are recognizable by gum exudation and longitudinal splitting of the bark.
Hosts and symptoms
Erythricium salmonicolor has a very broad host range. The host plants of greatest importance include rubber, tea, coffee, cacao, grapefruit, orange, nutmeg, mango, apple, coca, and kola. Pink Disease can cause heavy losses including individual branch death to the loss of the whole tree in cases where the main stem or several branches are affected. E. salmonicolor causes girdling cankers which prevent the normal function of some physiological processes, eventually leading to defoliation and die-back of outer branches. On rubber trees, initial stages of infection appear as drops of latex and silky-white mycelial growth on the bark surface. In black pepper plants, sterile pink to white pustules approximately 1 mm in diameter appear on young green stems. In citrus trees, sterile pustules may appear first, and in some cases the trees may have oozing sap or gum. In cacao trees, first symptoms of infection usually present as a sparse white mycelium on the bark surface, which can be easily overlooked. Trees are most susceptible in areas with high levels of rainfall, such as tropical rainforests. Diagnosis of Pink Disease is typically achieved through the use of light microscopy and scanning electron microscopy to observe sporulation of the pathogen.
Management and control
Management of E. salmonicolor and Pink Disease can be very difficult given its wide host range, making cross-infection a concern. Cultural control can be implemented by pruning frequently and burning any infected branches removed. This is effective when the disease can be recognized in the earliest stages, but it is most effective when performed concurrently with fungicide application. The encrustation and conidial pustules are able to remain functional for a period of time after the infected branches have been removed from the tree. Fungicide use varies among countries affected by the disease. In India, pre- and post-monsoon application of fungicides directly on the trunk and branches of cocoa or rubber trees effectively prevented the disease, while application of a sulphur-lime slurry to tea shrubs worked best in Kalimantan in Borneo, and Validamycin A was found to be the most effective means of control on rubber trees in Vietnam. The use of fungicides prevents the basidiospores from germinating and causing infection.
Importance
Erythricium salmonicolor is of particular importance in areas such as Colombia, China, or Thailand that rely on the export of globally important crops like coffee, tea, or rubber respectively. In cocoa, there have been reported losses of 80% or more in Western Samoa. Young trees are particularly affected by the disease, as Pink Disease typically does not kill mature trees it infects. in citrus trees in Brazil, E. salmonicolor has been shown to be responsible for reduction of citrus production by up to 10%.
See also
List of cacao diseases
List of citrus diseases
List of coffee diseases
List of mango diseases
List of tea diseases
References
External links
USDA ARS Fungal Database
Fungal tree pathogens and diseases
Cacao diseases
Fungal citrus diseases
Coffee diseases
Mango tree diseases
Tea diseases
Corticiales
Fungus species
Fungi described in 1875
Taxa named by Miles Joseph Berkeley
Taxa named by Christopher Edmund Broome | Erythricium salmonicolor | [
"Biology"
] | 798 | [
"Fungi",
"Fungus species"
] |
11,127,661 | https://en.wikipedia.org/wiki/Nectria%20radicicola | Nectria radicicola is a plant pathogen that is the causal agent of root rot and rusty root. Substrates include ginseng and Narcissus. It is also implicated in the black foot disease of grapevine. It is of the genus Nectria and the family Nectriaceae. N. radicicola is recognizable due to its unique anatomy, morphology, and the formation of its anamorph Cylindrocarpon desructans.
Distribution and habitat
N. radicicola is currently distributed evenly alongside its primary substrates American ginseng, Panax quinquefolius, and Korean ginseng, Panax ginseng. It occurs throughout North America and continental Asia, primarily Korea and China. It can alternate between growing with a host or remaining dormant as chlamydospores for years at a time if none is present. Because the spores are able to effectively overwinter in plant debris and soil, N. radicicola is not limited by seasonally colder climate conditions.
Life cycle
N. radicicola is a species complex of organisms which target the roots of various species of ginseng, grapevines, and some young trees as their primary substrate. The primary vector of infection are the chlamydospores which might survive for years in the soil before detecting and subsequently infecting a new host organism. Upon infecting the host organism hyphae begin to grow inter and intracellularly which subsequently causes the plant tissues to begin to rot. More chlamydospores will form once the hyphae reach the surface of the host tissue where micro and macronidia will sprout and release the spores.
Symptoms of infection of host plants
Root rot
After contracting root rot from N. radicicola, the plant will begin to wilt and eventually become discolored, transitioning from red-orange to brown-black with an accompanying strong odor resulting from the rot. The discoloration and odor may be localized only to lesions on the base of the stem and roots or spread across most of the plant. The roots will eventually dry out and become scaly and shriveled. In time the infection may invite secondary infections to take hold in addition to that from the N. radicicola from non-pathogenic sources.
Rusty root
Rusty root usually presents as slightly raised rust-colored spots at the crown of the taproot which will then spread to cover part or all of the root. The symptoms are only present on the surface of the root however and the discolored spots can be scraped off to reveal healthy tissue beneath. Rusty root is a less severe disease than root rot, with a much lower chance of inflicting serious long-lasting damage or death on the host plant and is associated with the less aggressive strains of the N. radicicola complex.
Newly burgeoning research
Double-stranded RNA makeup and virality
Research has shown that the virality of the N. radicicola is variable and highly dependent on the makeup of the double stranded RNA within the genotype. Phenotypic features which were closely related to virality such as laccase activity and sporulation were highly dependent on the amount and type of dsRNA present in the genome. This may indicate that the size of dsRNA present in a strain is a key indicator for viral success in different strains of the N. radicicola population.
Possible species separation between rusty root and root rot development
It has been observed that rusty root and root rot may either be inflicted on host plants, specifically various forms of ginseng, after contracting N. radicicola. Due to the increased severity of a root rot infection over rusty root, the strains which cause root rot are considered to be the more aggressive of the variations. New research suggests that the symptoms may actually arise from two different species rather than just the N. radicicola but rather that It has been observed that rusty root and root rot may either be inflicted on host plants, specifically ginseng, after contracting N. radicicola and due to the added severity, the strains which cause root rot are considered the more aggressive of the variations. Research suggests that the symptoms may actually arise from two different species rather than just the N. radicicola. Ilyonectria mors-panacis may be responsible for the root rot while the N. radicicola might only result in the observed rusty root. As the name suggests, Ilyonectria mors-panacis is closely related to Nectria radicicola, also known as Ilyonectria radicicola, but the genetic discrepancies between plants observed with root rot and rusty root are significant enough that what was thought to be merely different strains might actually be classified as arising from two different species of fungus.
References
Bibliography
Fungal plant pathogens and diseases
Food plant pathogens and diseases
Grapevine trunk diseases
radicicola
Fungi described in 1963
Fungus species | Nectria radicicola | [
"Biology"
] | 1,025 | [
"Fungi",
"Fungus species"
] |
11,127,674 | https://en.wikipedia.org/wiki/Cylindrocarpon%20ianthothele | Cylindrocarpon ianthothele is a fungal plant pathogen in the family Nectriaceae. It was described as a new species in 1917 by the German mycologist Hans Wilhelm Wollenweber. The type specimen was collected from rotten bulbs of Cyclamen persicum and on stems of Rubus idaeus growing in Denmark and Switzerland. Although some varieties and a form of the fungus have been proposed, they are now not considered to have independent taxonomic significance and have been folded into synonymy with the nominate variety.
References
Nectriaceae
Fungal plant pathogens and diseases
Fungi described in 1917
Fungus species | Cylindrocarpon ianthothele | [
"Biology"
] | 125 | [
"Fungi",
"Fungus species"
] |
11,127,681 | https://en.wikipedia.org/wiki/Rosellinia%20necatrix | Rosellinia necatrix is a fungal plant pathogen infecting several hosts including apples, apricots, avocados, cassava, strawberries, pears, hop. citruses and Narcissus, causing white root rot.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Apple tree diseases
Stone fruit tree diseases
Pear tree diseases
Avocado tree diseases
Root vegetable diseases
Fungal strawberry diseases
Food plant pathogens and diseases
Fungal citrus diseases
Fungi described in 1904
Xylariales
Fungus species | Rosellinia necatrix | [
"Biology"
] | 111 | [
"Fungi",
"Fungus species"
] |
11,127,691 | https://en.wikipedia.org/wiki/Diaporthe%20perniciosa | Diaporthe perniciosa a species of fungus in the family Diaporthaceae. It is a plant pathogen.
The names Phoma prunorum Cooke, Phomopsis prunorum (Cooke) Grove, and Phomopsis mali Roberts have been used for its asexual (anamorph) form.
It causes bark cankers on trees in the genera Malus (apples), Pyrus (pears) and Prunus (plums, cherries, peaches and other similar fruits). It has also been implicated in dieback disease of plums. One study in the late 1980s was able to isolate the fungus from several trees with die-back symptoms but inoculation of healthy trees with the fungus did not result in disease.
References
perniciosa
Fungi described in 1921
Fungal plant pathogens and diseases
Fungus species | Diaporthe perniciosa | [
"Biology"
] | 177 | [
"Fungi",
"Fungus species"
] |
11,127,700 | https://en.wikipedia.org/wiki/Diaporthe%20tanakae | Diaporthe tanakae is a plant pathogen.
References
Fungal plant pathogens and diseases
tanakae
Fungi described in 1982
Fungus species | Diaporthe tanakae | [
"Biology"
] | 27 | [
"Fungi",
"Fungus species"
] |
11,127,719 | https://en.wikipedia.org/wiki/Dilophospora%20alopecuri | Dilophospora alopecuri is a plant pathogen infecting rye and wheat.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Rye diseases
Wheat diseases
Dothideales
Fungi described in 1849
Taxa named by Elias Magnus Fries
Fungus species | Dilophospora alopecuri | [
"Biology"
] | 59 | [
"Fungi",
"Fungus species"
] |
11,127,724 | https://en.wikipedia.org/wiki/Diplocarpon%20coronariae | Diplocarpon coronariae is a plant pathogen that causes Marssonina blotch on apple.
Marssonina blotch
Marssonina blotch is a fungal disease of apple leaves and fruit that is caused by Diplocarpon coronaria.
Distribution
Marssonina blotch was historically an important apple disease in Japan and China. In the 1990s it became an important apple disease in India, and Korea. Marssonina blotch was detected in Europe by the early 2000s where it caused widespread disease, especially on organically managed apples. In the United States Marssonina blotch was first observed as a serious disease in 2017.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal tree pathogens and diseases
Apple tree diseases
Helotiales
Fungi described in 1903
Fungus species | Diplocarpon coronariae | [
"Biology"
] | 167 | [
"Fungi",
"Fungus species"
] |
11,127,730 | https://en.wikipedia.org/wiki/Botryosphaeria%20stevensii | Botryosphaeria stevensii (Apple sphaeropsis) is a fungal plant pathogen that causes cankers on several tree species including apple and juniper as well as causing cankers on grape vines. It causes branch dieback, possibly affecting a large portion of the tree canopy, and if severe it can kill entire plants.
It was originally found on fallen fruit of Malus pumila in Great Britain and published and described by Berk as Sphaeropsis malorum in 1836 . With the epithet 'malorum' derived from the Latin for Apple.
It is first seen as multiple very small, black pimples or pustules under the fruit skin before they break through the covering. Then a black conical protuberance appears, which is the spore-case of the fungus. Then a cluster of pale spores appears, on a short stem or pedicel. Later they turn black or black/brown and break off the pedicels. The spores then leave the spore-case by a small aperture at the top of the case. Infections can occur in winter or spring in the US.
Its anamorph was revealed to be Diplodia mutila.
It has been found on Rocky Mountain juniper (Juniperus scopulorum) in windbreak and ornamental plantings in the US.
Multiple, coalescing cankers resulted in branch dieback and sometimes tree mortality. The fungus also was pathogenic to and caused canker formation on eastern redcedar (Juniperus virginiana) and Chinese juniper (Juniperus chinensis)
Prevention efforts may include careful selection of plants, including resistant cultivars, planting in well-draining loose soils, exposure to light and plant spacing to reduce moisture retention.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Apple tree diseases
Grapevine trunk diseases
stevensii
Fungi described in 1964
Fungus species | Botryosphaeria stevensii | [
"Biology"
] | 383 | [
"Fungi",
"Fungus species"
] |
11,127,741 | https://en.wikipedia.org/wiki/Drechslera%20campanulata | Drechslera campanulata is a plant pathogen.
References
External links
USDA ARS Fungal Database
Pleosporaceae
Fungal plant pathogens and diseases
Taxa named by Joseph-Henri Léveillé
Fungi described in 1841
Fungus species | Drechslera campanulata | [
"Biology"
] | 49 | [
"Fungi",
"Fungus species"
] |
11,127,746 | https://en.wikipedia.org/wiki/Pyrenophora%20tritici-repentis | Pyrenophora tritici-repentis (teleomorph) and Drechslera tritici-repentis (anamorph) is a necrotrophic plant pathogen of fungal origin, phylum Ascomycota. The pathogen causes a disease originally named yellow spot but now commonly called tan spot, yellow leaf spot, yellow leaf blotch or helminthosporiosis. At least eight races of the pathogen are known to occur based on their virulence on a wheat differential set.
The tan (yellow) spot fungus was first described by Nisikado in 1923 in Japan. and was later identified in Europe, Australia and the US, in the mid 1900s. The disease is one of the most important fungal disease on wheat and the fungal pathogen is found to infect in all parts of the world wherever wheat and other susceptible host crops are found. P. tritici-repentis overwinters on stubble, and due to recent heavily no-till/residue retention cultural practices, increased incidence and yield loss of up to 49% has been witnessed if ideal conditions occur. It forms characteristic, dark, oval-shaped spots of necrotic tissue surrounded by a yellow ring. It is responsible for losses that account for up to 30% of the crop, due to its effects reducing photosynthesis. Pathogenesis and toxicity in P. tritici-repentis is controlled by a single gene, transformations of this gene cause the pathogen to become benign when interacting with wheat. This has major implications for those in agriculture seeking to combat the effects of this fungus.
Hosts and symptoms
Tan spot is found primarily on wheat, but is also found to infect other cereals and grasses including triticale, barley, and rye, but are less frequently affected. Other grass species affected by the pathogen include Siberian wheat grass, sand bluestem, meadow brome, sheep fescue, June grass, little bluestem, green foxtail, needle and thread, and tall wheatgrass. While these are not necessarily agriculture crop hosts such as wheat, the pathogen is able to form and survive on many grass hosts, which can eventually venture into wheat fields. Other important grass susceptible hosts include smooth brome which can be found in pastures, as well as quack grass that is found in the environment and considered a weed in many agricultural crops. Lesions typically appear on both upper and lower leaf surfaces, and initially are tan to brown specks. Eventually, the tan to brown specks expand to larger irregular, oval, lens-shaped, ellipse, tan blotches with a yellow ring around them. The yellow ring is often referred to as a halo, yellow discoloration as chlorosis, and browning/death of leaf tissue as necrosis. The development of a dark brown to black spot in the center the lesion is characteristic of the disease. If warmer temperatures and moist conditions persist, spores known as conidia will move up plant as secondary inoculum and can also infect head/spikes. Symptoms on the head are indistinct, but can cause brownish glumes, and grains can have a reddish appearance similar to the pathogen Fusarium.
Disease cycle
P. tritici-repentis survives and overwinters as pseudothecia on stubble from the previous year's infected crop. The pseudothecia contain ascospores (sexual spores). Such ascospores produced are large and typically dispersed by wind, but do not travel far due to their size. The ascospores land on leaf surfaces and begin to produce lesions by infection from appressorium and infection peg. The lesions initially formed by ascospores, known as condo, form atop of conidiophores, and can serve as primary inoculum to new plant/host via long distance wind dispersal. Condo can also serve as primary inoculum via rain splash to further more up primary host and re-infect. During and after maturation of the wheat crop, fungus can grow saprophytically as mycelium from the infected leaf blade, down the leaf sheath, and on to the stem where it will later form a pseudothecia. The disease develops over a wide temperature range, but is favored by warmer temperatures along with or followed by long rains, dew, or irrigation.
Environment
The fungus requires 6-24+ hours of moisture to infect a leaf. This means that rain, significant dew or high canopy humidity are factors that can lead to infection. Optimal temperatures for symptom development range from .
Control
Since this disease can cause considerable yield loss, effective control is very important. The most effective method of long term control is crop rotation. There is a considerable difference in the fungal population after one year of rotation. Examples of non-host crops include mustard, flax, and soybean. Some other control options include tillage. Foliar fungicides can also be used as control methods. Since the top two leaves contribute the most to yield, it is important to protect them. Some effective fungicides include, but are not limited to, Headline, Quilt, and Stratego. There are however, resistant varieties that make most methods of control unnecessary. There is research to suggest that plant height may also influence the amount of disease able to form due to the pathogen. It suggests that shorter plants will have a lowered chance of infection. This research has only been conducted in Canada however, and should lead to more research before being used as a control technique.
Out of all wheat pathogens, Ptr is among the best studied. Among all necrotrophic pathogen of this crop, Ptrs and Parastagonospora nodorums effectors have become the best studied.
Host resistance
Some resistance genes – especially against races 1 and 5, the most problematic in Kazakhstan – have been identified.
Importance
This disease is considered to be a very important one. According to the University of Nebraska, losses of 50 percent have been documented. This negatively impacts the profitability a farmer can hope to achieve within one year. Tan spot is recognized as "one of the major constraints of wheat production. This is also a very significant disease in Canada, creating similar yield losses annually. Tan spot is important enough and causing large enough yield losses to continually prompt new research. P. t-r. has caused serious epidemics in Kazakhstan since the 1980s with nearly half the national harvest being lost when there is an epidemic.
References
External links
Tan Spot, Kansas State University
tritici-repentis
Fungal plant pathogens and diseases
Wheat diseases
Fungi described in 1923
Fungus species | Pyrenophora tritici-repentis | [
"Biology"
] | 1,357 | [
"Fungi",
"Fungus species"
] |
11,127,754 | https://en.wikipedia.org/wiki/Drechslera%20wirreganensis | Drechslera wirreganensis is a plant pathogen causing Platyspora Leaf Spot.
Distribution
Argentina, Australia, Canada, Egypt, New Zealand, South Africa, and the United States of America.
Life cycle
D. wirreganensis is a seedborne pathogen.
References
Fungal plant pathogens and diseases
Pleosporaceae
Fungus species
Fungi described in 1992 | Drechslera wirreganensis | [
"Biology"
] | 77 | [
"Fungi",
"Fungus species"
] |
11,127,759 | https://en.wikipedia.org/wiki/Elsino%C3%AB%20veneta | Elsinoë Veneta is a plant pathogen, the causal agent of the anthracnose of raspberry.
References
External links
USDA ARS Fungal Database
Elsinoë
Fungal plant pathogens and diseases
Small fruit diseases
Fungi described in 1917
Raspberry diseases
Fungus species | Elsinoë veneta | [
"Biology"
] | 58 | [
"Fungi",
"Fungus species"
] |
11,127,761 | https://en.wikipedia.org/wiki/Eremothecium%20coryli | (originally ) is a plant pathogen that causes stigmatomycosis.
Description
It is cultivated on potato dextrose agar and grows as yeast-like oval or spherical budding cells either isolated or in short chains and has few hyphae which are septate at maturity. In addition to buds, the yeast produces many asci (or sporiferous sacs or sporangia) that are cylindrical to naviculate, with two to eight needle-like ascospores arranged lengthwise. Ascospores are apiculate to fusiform, with a distinct septum at or near the center and the upper cell slightly broader at the septum, and after liberation are held together in a mass by long appendages. colonies are creamy and perfectly round. The yeast grows at 10–37 °C, with an optimum range of 30–35 °C. More asci form at 15–20 °C than 25–35 °C.
See also
List of soybean diseases
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Saccharomycetes
Soybean diseases
Fungus species
Fungi described in 1995 | Eremothecium coryli | [
"Biology"
] | 234 | [
"Fungi",
"Fungus species"
] |
11,127,769 | https://en.wikipedia.org/wiki/Gibberella%20zeae | Gibberella zeae, also known by the name of its anamorph Fusarium graminearum, is a fungal plant pathogen which causes fusarium head blight (FHB), a devastating disease on wheat and barley. The pathogen is responsible for billions of dollars in economic losses worldwide each year. Infection causes shifts in the amino acid composition of wheat, resulting in shriveled kernels and contaminating the remaining grain with mycotoxins, mainly deoxynivalenol (DON), which inhibits protein biosynthesis; and zearalenone, an estrogenic mycotoxin. These toxins cause vomiting, liver damage, and reproductive defects in livestock, and are harmful to humans through contaminated food. Despite great efforts to find resistance genes against F. graminearum, no completely resistant variety is currently available. Research on the biology of F. graminearum is directed towards gaining insight into more details about the infection process and reveal weak spots in the life cycle of this pathogen to develop fungicides that can protect wheat from scab infection.
Life cycle
F. graminearum is a haploid homothallic ascomycete. The fruiting bodies, perithecia, develop on the mycelium and give rise to ascospores, which land on susceptible parts of the host plant to germinate. The fungus causes fusarium head blight on wheat, barley, and other grass species, as well as ear rot on corn. The primary inocula are the ascospores, sexual spores which are produced in the perithecia. Spores are forcibly discharged and can germinate within six hours upon landing on the plant surface. The scab disease is monocyclic; after one cycle of infection with ascospores, the fungus produces macroconidia by asexual reproduction. These structures overwinter in the soil or in plant debris on the field and give rise to the mycelium in the next season.
Host and symptoms
The pathogen is capable of causing a variety of diseases: head blight or 'scab' on wheat (Triticum), barley (Hordeum), rice (Oryza), oats (Avena), and Gibberella stalk and ear rot disease on maize (Zea). Additionally, the fungus may infect other plant species without causing any disease symptoms.
Maize
In Gibberella stalk rot, the leaves on early-infected plants will turn a dull greyish-green, and the lower internodes will soften and turn a tan to dark-brown. A pink-red discoloration occurs within the stalks of diseased tissue. Shredding of the pith may reveal small, round, black perithecia on the stalks. Gibberella (red) ear rot can have a reddish mold that is often at the ear tip. The infection occurs by colonizing corn silk and symptoms first occur at the ear's apex. The white mycelium turns from pink to red over time, eventually covering the entire ear. Ears that become infected early do not fully develop the reddish mold near the ear tip, as the mold grows between the husks and ear.
Rice
Gibberella zeae can turn affected seeds red and cause brown discoloration in certain areas on the seed or the entire seed surface. The surface of husks develop white spots that later become yellow and salmon or carmine. Infected grains are light, shrunken and brittle. Stem nodes begin to rot and wilt, eventually causing them to turn black and disintegrate when they are infected by the fungal pathogen.
Wheat
Brown, dark purple-black necrotic lesions will form on the outer surface of the spikelets, what the wheat ear breaks up into. The lesions may be referred to as scabs, but this is not to be confused and associated with other scab diseases such as those with different host and pathogen. Head blight is visible before the spikes mature. Spikelets begin to appear water-soaked before the loss of chlorophyll, which gives a white straw color. Peduncles that are directly under the inflorescence can become discolored into a brown-purple color. Tissues of the inflorescence typically become blighted into a bleached tan appearance, and the grain within it atrophies. The awn will become deformed, twisted and curve in a downward direction.
Barley
Infections on barley are not always visible in the field. Similar to wheat, infected spikelets show a browning or water-soaked appearance. The infected kernels display a tan to dark brown discoloration. During long periods of wetness, pink to salmon-orange spore masses can be seen on the infected spikelets and kernels. The cortical lesions of infected seeds become a reddish-brown in cool, moist soil. Warm soil can cause head blight to occur after emergence, and crown and basal culm rot can be observed in later plant development.
Infection process
F. graminearum infects wheat spikes from anthesis through the soft dough stage of kernel development. The fungus enters the plant mostly through the flowers; however, the infection process is complex and the complete course of colonization of the host has not been described. Germ tubes seem not to be able to penetrate the hard, waxy surface of the lemma and palea which protect the flower. The fungus enters the plant through natural openings such as stomates, and needs soft tissue such as the flowers, anthers and embryo to infect the plant. From the infected floret, the fungus can grow through the rachis and cause severe damage in a short period of time under favorable conditions. Upon germination of the spores on the anthers and the surface of the developing kernel, hyphae penetrate the epicarp and spread through the seed coat. Successively, the different layers of the seed coat and finally the endosperm are colonized and killed.
Management
The control of this disease can be achieved using a combination of the following strategies: fungicide applications, resistance breeding, proper storage, crop rotation, crop residue tillage, and seed treatment. The correct usage of fungicide applications against fusarium head blight (FHB) can reduce the disease by 50 to 60 percent. Fusarium refers to a large genus of soil fungi that are economically important due to the profound effects they have on crops. Application of fungicides is necessary at early heading date for barley and early flowering for wheat, where the early application can limit the infection of the ear. Barley and wheat differ in fungicide application because of their differences in developmental traits. Some biofungicides control FHB. Scaglioni et al., 2019 extract phenols from Spirulina spp. and demonstrate growth retardation by 25% (per weight). The disease generally develops late in the season or during storage, so fungicide use is only effective in the early season. Management against insect pests such as ear borers, for corn, will also reduce the infection of the ear from wounds caused by insect feeding.
Cultivating a variety of hosts that are resistant to FHB is one of the most evidence-based and cost-effective ways to manage the disease. Using varieties that have looser tusks that cover the ear are less vulnerable to FHB. Once the crop has been harvested, it is essential to store it at low moisture, below 15%, as this will reduce the appearance of Gibberella zeae and Fusarium species in storage.
Avoiding the planting of small grain crops following other small grain crops or corn and tillage of crop residue minimizes the chances of FHB in environmentally favorable years. The rotation of small grains with soybean or other non-host crops has proven to reduce FHB and mycotoxin contamination. Crop rotation with the tillage of residue prevents crops from remaining to infect on the soil surface. Residues can provide an overwintering medium for Fusarium species to cause FHB. As a result, the chances of infection are greatly improved in the succeeding small grain crop. If minimal or no tillage occurs, the residue spreads and allows the fungus to overwinter on stalks and rotted ears of corn and produce spores.
The seeds (kernels) that colonize with the fungus have less resistance because of poor germination. Planting certified or treated seeds can reduce the amount of seedling blight, which is caused by the seeds colonized with the fungus. If it is necessary to replant seeds that were harvested from a FHB infected field, then the seeds should be treated to avoid reoccurrence of the infection.
Importance
The loss of yield and contamination of seed with mycotoxins, alongside reduced seed quality, are the main contributions to the impact of this disease. Two mycotoxins, the trichothecene deoxynivalenol (DON), a strong biosynthesis inhibitor, and zearalenone, an estrogenic mycotoxin, can be found in grains after FHB epidemics. DON is a type of vomitoxin and, as its name states, is an antifeedant. Livestock that consume crops contaminated with vomitoxin become sick and refuse to eat anymore. Zearalenone is a phytoestrogen, mimicking mammals' estrogen. It can be disastrous if it gets into the food chain, as zearalenone causes abortions in pregnant females and feminization of males.
In 1982, a major epidemic affected of the spring wheat and barley growing in the northern Great Plains of North Dakota, South Dakota, and Minnesota. The yield losses exceeded worth approximately $826 million, with total losses related to the epidemic near one billion dollars. Years that followed this epidemic, reported losses that have been estimated between $200-$400 million annually. Losses in barley because of FHB are large in part due to the presence of DON. Barley prices from 1996 in Minnesota fell from $3.00 to $2.75 per bushel if the mycotoxin was present and another $0.05 for each part per million of DON present.
DON chemotypes of F. graminearum include .
See also
Ascomycota
Ascospore
Fusarium graminearum genome database
Homothallic
References
External links
Interactive Science Experiment Showcasing the Growth of Gibberella zeae (GCSE/A-level)
Fusarium graminearum Database
Index Fungorum
USDA ARS Fungal Database
zeae
Fungal plant pathogens and diseases
Barley diseases
Wheat diseases
Fungi described in 1822
Taxa named by Lewis David de Schweinitz
Fungus species | Gibberella zeae | [
"Biology"
] | 2,223 | [
"Fungi",
"Fungus species"
] |
11,127,776 | https://en.wikipedia.org/wiki/Gibberella%20stilboides | Gibberella stilboides is a nectriacine fungus. It is a plant pathogen, and causes collar rot in coffee seedings.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
stilboides
Fungi described in 1924
Fungus species | Gibberella stilboides | [
"Biology"
] | 58 | [
"Fungi",
"Fungus species"
] |
11,127,782 | https://en.wikipedia.org/wiki/Fusicoccum%20aesculi | Fusicoccum aesculi is a fungus and a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Botryosphaeriales
Fungus species | Fusicoccum aesculi | [
"Biology"
] | 43 | [
"Fungi",
"Fungus species"
] |
11,127,792 | https://en.wikipedia.org/wiki/Fusicoccum%20amygdali | Fusicoccum amygdali is a plant pathogen, which often releases a toxin known as fusicoccin that causes the stomata of the plant to open.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Botryosphaeriaceae
Fungi described in 1905
Fungus species | Fusicoccum amygdali | [
"Biology"
] | 64 | [
"Fungi",
"Fungus species"
] |
11,127,815 | https://en.wikipedia.org/wiki/Gaeumannomyces%20graminis%20var.%20graminis | Gaeumannomyces graminis var. graminis is a plant pathogen. This fungal pathogen produces extensive damage on the sheath of rice, causing black spots which protrude from the infected. This pathogen also generates a discoloration in the foliage of a plant which tends to show a straw orange colouration.
References
External links
Index Fungorum
USDA ARS Fungal Database
Further reading
Fungal plant pathogens and diseases
Rice diseases
Magnaporthales
Fungus species
Taxa named by Pier Andrea Saccardo | Gaeumannomyces graminis var. graminis | [
"Biology"
] | 103 | [
"Fungi",
"Fungus species"
] |
11,127,821 | https://en.wikipedia.org/wiki/Ganoderma%20philippii | Ganoderma philippii is a plant pathogen infecting cacao, tea and coffee trees.
References
Fungal plant pathogens and diseases
Cacao diseases
Coffee diseases
Tea diseases
philippii
Fungi described in 1891
Fungus species | Ganoderma philippii | [
"Biology"
] | 44 | [
"Fungi",
"Fungus species"
] |
11,127,825 | https://en.wikipedia.org/wiki/Geastrumia%20polystigmatis | Geastrumia polystigmatis is an ascomycete fungus that is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Enigmatic Ascomycota taxa
Fungus species
Fungi described in 1960 | Geastrumia polystigmatis | [
"Biology"
] | 56 | [
"Fungi",
"Fungus species"
] |
11,127,829 | https://en.wikipedia.org/wiki/Gibberella%20xylarioides | Gibberella xylarioides (Fusarium xylarioides) is a species of fungus in the family Nectriaceae. It is the causative agent of coffee wilt disease (CWD). The disease caused a severe problem in several countries in West and East Africa during the 1940s and 1950s. CWD was first seen in Coffea liberica.
Hosts
Main hosts
Coffea arabica (arabica coffee)
Coffea canephora (robusta coffee)
Coffea liberica (Liberian coffee tree)
Other hosts
Gossypium (cotton)
Musa × paradisiaca (plantain)
Signs and symptoms
Similar to other vascular wilt pathogens, the fungus colonizes the xylem and causes the flow of water to be cut off. It can be diagnosed by several visual signs. The leaves can wilt, have vein necrosis, and abscission. The coffee bark, when scraped with a knife, will have a blue-black coloration. The berries will appear as though they are ripening prematurely but will stay on the coffee plant after the leaves have fallen off. Necrosis can often be seen near the collar of the plant.
Young trees can be killed within a few days of infection while more mature coffee plants can survive up to 8 months.
Gibberella xylarioides (Sexual form) will make purple perithecia and ascospores, but resting structures are rarely found in the soil. Fusarium xylarioides (Asexual form) make sickle shaped conidia and are spread by wind, rain, and human activities like weeding and harvesting.
Management
Other methods of management include:
Removal of diseased trees and burning is the most successful method of eradication of Coffee Wilt. Coffea sp. should not be replanted in soil for six months to avoid infection of seedlings.
Care when weeding around coffee plants to avoid injuring the bark as the fungus can enter the bark through wounds
Using planting tools that are free of disease
Spraying the soil surface with 2.5% copper (II) sulphate
Breeding resistance—"The results of greenhouse inoculation experiments proved that there was important diversity in coffee populations (within and among the forest sites) in reaction to G. xylariodies infection."
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
xylarioides
Fungi described in 1948
Fungus species | Gibberella xylarioides | [
"Biology"
] | 503 | [
"Fungi",
"Fungus species"
] |
11,127,834 | https://en.wikipedia.org/wiki/Gibellina%20cerealis | Gibellina cerealis is a fungal plant pathogen. It is a pathogen of wheat and similar species, causing white foot rot or basal stem rot.
References
Fungal plant pathogens and diseases
Magnaporthales
Fungus species | Gibellina cerealis | [
"Biology"
] | 45 | [
"Fungi",
"Fungus species"
] |
11,127,840 | https://en.wikipedia.org/wiki/Clonostachys%20rosea%20f.%20rosea | Clonostachys rosea f. rosea, also known as Gliocladium roseum, is a species of fungus in the family Bionectriaceae. It colonizes living plants as an endophyte, digests material in soil as a saprophyte and is also known as a parasite of other fungi and of nematodes. It produces a wide range of volatile organic compounds which are toxic to organisms including other fungi, bacteria, and insects, and is of interest as a biological pest control agent.
Biological control
Clonostachys rosea protects plants against Botrytis cinerea ("grey mold") by suppressing spore production. Its hyphae have been found to coil around, penetrate, and grow inside the hyphae and conidia of B. cinerea.
Nematodes are infected by C. rosea when the fungus' conidia attach to their cuticle and germinate, going on to produce germ tubes which penetrate the host's body and kill it.
Biofuels
In 2008 an isolate of Clonostachys rosea (NRRL 50072) was identified as producing a series of volatile compounds that are similar to some existing fuels, including diesel. However, the taxonomy of this isolate was later revised to Ascocoryne sarcoides.
See also
Entomopathogenic fungus
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Fungi described in 1999
Bionectriaceae
Anaerobic digestion
Forma taxa | Clonostachys rosea f. rosea | [
"Chemistry",
"Engineering"
] | 321 | [
"Water technology",
"Anaerobic digestion",
"Environmental engineering"
] |
11,127,846 | https://en.wikipedia.org/wiki/Phyllachora%20pomigena | Phyllachora pomigena is a plant pathogen responsible for Sooty blotch and flyspeck disease, a disease affecting apples and pears. It appears as a brown or black blotch ( in diameter) on the fruit. Spots may coalesce to cover the entire fruit. During the summer these diseases develop during cool rainy weather, particularly in dense, unpruned trees with poor air circulation. Although unsightly, the fruit is still edible. The sooty blotch will wipe off of the fruit.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Apple tree diseases
Pear tree diseases
Phyllachorales
Fungus species
Taxa named by Lewis David de Schweinitz | Phyllachora pomigena | [
"Biology"
] | 152 | [
"Fungi",
"Fungus species"
] |
11,127,857 | https://en.wikipedia.org/wiki/Sydowiella%20depressula | Sydowiella depressula is a fungal plant pathogen infecting caneberries.
References
Fungal plant pathogens and diseases
Small fruit diseases
Fungi described in 1873
Fungus species | Sydowiella depressula | [
"Biology"
] | 36 | [
"Fungi",
"Fungus species"
] |
11,127,861 | https://en.wikipedia.org/wiki/Gnomonia%20rubi | Gnomonia rubi is a fungal plant pathogen that causes cane canker on Rubus.
References
Fungal plant pathogens and diseases
Small fruit diseases
Gnomoniaceae
Fungi described in 1885
Fungus species | Gnomonia rubi | [
"Biology"
] | 42 | [
"Fungi",
"Fungus species"
] |
11,127,866 | https://en.wikipedia.org/wiki/Gymnoconia%20nitens | Gymnoconia nitens is a species of rust fungus in the Phragmidiaceae family. It is a plant pathogen, and causes orange rust on various berries. The species was originally described in 1822 by mycologist Lewis David de Schweinitz as Aecidium luminatum.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Pucciniales
Fungi described in 1822
Fungus species | Gymnoconia nitens | [
"Biology"
] | 87 | [
"Fungi",
"Fungus species"
] |
11,127,872 | https://en.wikipedia.org/wiki/Hapalosphaeria%20deformans | Hapalosphaeria deformans is an ascomycete fungus. It is the causal organism of Stamen Blight of caneberry. It is a common disease in Pacific Northwest of North America (especially west of the Cascades, especially in Oregon), elsewhere in Canada, Denmark, Germany, Great Britain, Ireland, and Spain. It affects the commercial harvest of Oregon dewberries, and boysenberries and cascadeberries in British Columbia. It is not commercially significant in red raspberry in Scotland.
Hosts
Caneberries are hosts. Among cane species, known domesticated hosts are blackberry, boysenberry, cascadeberry, evergreen blackberry, loganberry, red raspberry, and youngberry, and nine wild Rubus including wild red raspberry.
See also
List of caneberries diseases
References
External links
Index Fungorum
USDA ARS Fungal Database
Enigmatic Ascomycota taxa
Fungal plant pathogens and diseases
Fungus species
Fungi described in 1907 | Hapalosphaeria deformans | [
"Biology"
] | 196 | [
"Fungi",
"Fungus species"
] |
11,127,880 | https://en.wikipedia.org/wiki/Helicobasidium%20purpureum | Helicobasidium purpureum is a species of fungus in the subdivision Pucciniomycotina. Basidiocarps (fruit bodies) are corticioid (patch-forming) and are typically violet to purple. Microscopically they have auricularioid (laterally septate) basidia. Helicobasidium purpureum is an opportunistic plant pathogen and is one of the causes of violet root rot of crops and other plants. DNA sequencing suggests that it is a complex of more than one species. The species has a conidia-bearing anamorph in the Tuberculina persicina complex that is a parasite of rust fungi.
Taxonomy
Helicobasidium purpureum was first described from France in 1885 by French mycologist Narcisse Patouillard to accommodate a species with an effused, purple, corticioid fruit body and unusual curved or helicoid basidia. Patouillard described it as the only species in his new genus Helicobasidium. Patouillard was apparently unaware that Edmond Tulasne had described the same or a similar species under the name Hypochnus purpureus in 1865. Initial molecular research, based on cladistic analysis of DNA sequences, indicates that at least two species occur in the H. purpureum complex in Europe.
Persoon had described a sclerotia-forming anamorph in 1801 as Sclerotium crocorum, moved by de Candolle in 1815 to his new genus Rhizoctonia. Subsequent authors described a number of additional species in Rhizoctonia which are currently considered synonyms of R. crocorum (later called Thanatophytum crocorum). DNA evidence indicates that at least two species occur in the Thanatophytum crocorum complex in Europe, one of which is an anamorph of a species in the H. purpureum complex, the other a species in the Helicobasidium longisporum complex.
The rust parasite Tuberculina persicina is a further anamorph linked to Helicobasidium purpureum, but again represents a complex of at least four species, two of which are linked to H. longisporum.
Description
Basidiocarps are corticioid smooth, membranaceous, purple to purple-brown. Microscopically the hyphae are easily visible, 5–8 μm diam., brownish-purple, and lack clamp connections. Basidia are tubular, curved or crook-shaped, and auricularioid (laterally septate). Basidiospores are oblong and often weakly curved, mostly 8–13 x 4.5–6 μm.
Distribution
Helicobasidium purpureum has been recorded mainly from temperate areas of America, Asia, and Europe. It is reported to cause violet root rot of various crops.
References
Fungal plant pathogens and diseases
Vegetable diseases
Fungi described in 1885
Taxa named by Narcisse Théophile Patouillard
Fungi of Europe
Fungus species | Helicobasidium purpureum | [
"Biology"
] | 658 | [
"Fungi",
"Fungus species"
] |
11,127,883 | https://en.wikipedia.org/wiki/Helicobasidium%20longisporum | Helicobasidium longisporum is a species of fungus in the subdivision Pucciniomycotina. Basidiocarps (fruit bodies) are corticioid (patch-forming) and are typically violet to purple. Microscopically they have auricularioid (laterally septate) basidia. Helicobasidium longisporum is an opportunistic plant pathogen and is one of the causes of violet root rot of crops and other plants. DNA sequencing suggests that it is a complex of more than one species.
Taxonomy
Helicobasidium longisporum was first described from Uganda in 1917 by British mycologist Elsie Wakefield to accommodate a species similar to Helicobasidium purpureum but with elongated basidiospores. It was found parasitizing roots of cocoa (Theobroma cacao). A similarly long-spored Japanese taxon was described as H. mompa f. macrosporum and a further long-spored species was subsequently described from Indonesia as H. compactum. All three were considered conspecific in a 1999 study.
In 1955 Japanese mycologist Seiya Ito synonymized H. mompa f. macrosporum and H. compactum with a short-spored species, Helicobasidium mompa. As a result, at least some subsequent references to H. mompa refer to a long—spored species.
Initial molecular research, based on cladistic analysis of DNA sequences, indicates that at least two species occur in the H.longisporum complex, one in Europe (together with its Tuberculina anamorph) and one in Africa and the Americas (also with its anamorph).
Description
Basidiocarps are corticioid smooth, membranaceous, purple to purple-brown. Microscopically the hyphae are easily visible, 5–8 μm diam., brownish-purple, and lack clamp connections. Basidia are tubular, curved or crook-shaped, and auricularioid (laterally septate). Basidiospores are elongated clavate, mostly 16–25 x 4.5–6 μm.
Distribution
Helicobasidium longisporum has been recorded from both temperate and tropical areas of Africa, America, Asia, Australia, and Europe. It is reported to cause violet root rot of various crops and a similar collar rot or collar canker of coffee trees.
References
Fungal plant pathogens and diseases
Fungi described in 1917
Fungi of Africa
Pucciniomycotina
Fungus species | Helicobasidium longisporum | [
"Biology"
] | 540 | [
"Fungi",
"Fungus species"
] |
11,127,891 | https://en.wikipedia.org/wiki/Helminthosporium%20papulosum | Helminthosporium papulosum is a fungal plant pathogen that causes blister canker on pear and apple.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal tree pathogens and diseases
Apple tree diseases
Pear tree diseases
Pleosporaceae
Fungus species
Fungi described in 1934 | Helminthosporium papulosum | [
"Biology"
] | 63 | [
"Fungi",
"Fungus species"
] |
11,127,900 | https://en.wikipedia.org/wiki/Hemileia%20coffeicola | Hemileia coffeicola is a plant pathogen which infects coffee plantations in central to western Africa, particularly in Cameroon and São Tomé and Príncipe.
Description
Hemileia coffeicola is a grey or orange rust fungus whose urediniospores are ornamented with warts or spines. Its sori are found scattered over leaf surfaces particularly on the entire underside of the leaf giving it the appearance of powdery blotches. It can be distinguished from the very similar Hemileia vastatrix by the way in which the sori are scattered over the leaf surface rather than being found in distinct patches. The presence hyphae measuring up to 20–30 μm in diameter can also be used to distinguish H. coffeicola from H. vastatrix. It was first recorded on Coffea arabica in Cameroon in 1932. Infected leaves eventually turn yellow and are desiccated.
References
External links
Index Fungorum
USDA ARS Fungal Database
Pucciniomycotina
Coffee diseases
Fungus species
Fungi described in 1934 | Hemileia coffeicola | [
"Biology"
] | 218 | [
"Fungi",
"Fungus species"
] |
11,127,907 | https://en.wikipedia.org/wiki/Hypochnus%20ochroleucus | Hypochnus ochroleucus is a fungal plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Thelephorales
Fungus species | Hypochnus ochroleucus | [
"Biology"
] | 41 | [
"Fungi",
"Fungus species"
] |
11,127,912 | https://en.wikipedia.org/wiki/Kuehneola%20uredinis | Kuehneola uredinis is a plant pathogen. Kuehneola uredinis is a fungal pathogen that causes cane and leaf rust only in Rubus cultivars or wild and ornamental blackberry species.
References
External links
USDA ARS Fungal Database
Kuehneola uredinis In: DrfpLib
Pucciniales
Fungal plant pathogens and diseases
Fungi described in 1824
Galls
Taxa named by Johann Heinrich Friedrich Link
Fungus species | Kuehneola uredinis | [
"Biology"
] | 93 | [
"Fungi",
"Fungus species"
] |
11,127,922 | https://en.wikipedia.org/wiki/Lasiodiplodia%20theobromae | Lasiodiplodia theobromae is a plant pathogen with a very wide host range. It causes rotting and dieback in most species it infects. It is a common post harvest fungus disease of citrus known as stem-end rot. It is a cause of bot canker of grapevine. It also infects Biancaea sappan, a species of flowering tree also known as Sappanwood.
On rare occasions it has been found to cause fungal keratitis, lesions on nail and subcutaneous tissue.
It has been implicated in the widespread mortality of baobab (Adansonia digitata) trees in Southern Africa. A preliminary study found the deaths to have a complex set of causes requiring detailed research.
Host and symptoms
L. theobromae causes diseases such as dieback, blights, and root rot in a variety of different hosts in tropical and subtropical regions. These include guava, coconut, papaya, and grapevine. Botryosphaeria dieback, which is formerly known as bot canker, is characterised by a range of symptoms that affect grapevine in particular. These symptoms affect different areas on the plant and can be used to diagnose this disease along with other factors. In the trunk and cordon of the plant symptoms include cankers coming out of the wounds, wedge shaped lesions when cut in cross sections and dieback. Dieback is characterized as a ‘dead arm’ and a loss of spur positions. More symptoms include stunted shoots in the spring, delay or lack of growth in the spur positions of the bud burst, bleached canes and necrotic buds. Bud necrosis, bud failure, and the dieback of arms are all a result of the necrosis of the host's vascular system.
It can also affect the fruit of durians such as Durio graveolens.
Disease cycle
The fungus over-winters as pycnidia on the outside of diseased wood. The pycnidia produces and releases two-celled, dark brown, striated conidia. The conidia are then dispersed by wind and rain splash, spreading the fungi to other vines, and from one part of the vine to another. Disease develops when conidia land on freshly cut or damaged wood. The conidia germinate the tissue of the wood and start causing damage to the vascular system. Cankers begin to form around the initial infection point and eventually complete damage of the vascular system causes necrosis and dieback of the wood. In some instances, pseudothecia form on the outside of cankers and produce ascospores which are then dispersed like conidia and infect surrounding wounds.
Management
There are many different procedures that can be implemented to manage dieback in a vineyard. These can either be done to prevent further infection by breaking the disease cycle or to recover plants after initial infection. Good hygiene must be practiced when removing infection sources in order to prevent further infection to the rest of the vineyard as well as to avoid cross contamination. Strategies that can be used for prevention and recovery are listed in the table below:
References
External links
USDA ARS Fungal Database
Botryosphaeriaceae
Fungal tree pathogens and diseases
Cacao diseases
Fungal citrus diseases
Grapevine trunk diseases
Fungus species | Lasiodiplodia theobromae | [
"Biology"
] | 666 | [
"Fungi",
"Fungus species"
] |
11,127,931 | https://en.wikipedia.org/wiki/Lepteutypa%20cupressi | Lepteutypa cupressi is a plant pathogen which causes a disease ("Cypress canker") in Cupressus, Thuja, and related conifer types.
The name Seiridium cupressi (formerly Coryneum cupressi) is for the anamorph of this fungus, that is, it is used for the asexual form. Now that it is known to have a sexual stage the genus name Lepteutypa should take precedence.
References
External links
USDA ARS Fungal Database
Xylariales
Fungal tree pathogens and diseases
Fungi described in 1973
Fungus species | Lepteutypa cupressi | [
"Biology"
] | 127 | [
"Fungi",
"Fungus species"
] |
11,127,949 | https://en.wikipedia.org/wiki/Phaeosphaeria%20herpotrichoides | Phaeosphaeria herpotrichoides is a fungal plant pathogen that infects the commercial crops rye and wheat.
It is common in Iceland where it infects a range of host species, including the wood of Betula pubescens, and the leaves of Dactylis glomerata, Deschampsia caespitosa, Kobresia myosuroides, Leymus arenarius, Luzula spicata, Milium effusum, Phleum pratense, Poa alpina, Poa glauca and Poa nemoralis.
References
Fungal plant pathogens and diseases
Rye diseases
Wheat diseases
Phaeosphaeriaceae
Fungi described in 1863
Taxa named by Giuseppe De Notaris
Fungus species | Phaeosphaeria herpotrichoides | [
"Biology"
] | 154 | [
"Fungi",
"Fungus species"
] |
11,127,956 | https://en.wikipedia.org/wiki/Phaeosphaeria%20microscopica | Phaeosphaeria microscopica is a fungal plant pathogen that infects wheat.
References
Fungal plant pathogens and diseases
Wheat diseases
Phaeosphaeriaceae
Fungi described in 1872
Taxa named by Petter Adolf Karsten
Fungus species | Phaeosphaeria microscopica | [
"Biology"
] | 49 | [
"Fungi",
"Fungus species"
] |
11,127,965 | https://en.wikipedia.org/wiki/Leptosphaerulina%20trifolii | Leptosphaerulina trifolii is a plant pathogen.
See also
List of soybean diseases
References
Fungal plant pathogens and diseases
Pleosporaceae
Soybean diseases
Fungi described in 1959
Fungus species | Leptosphaerulina trifolii | [
"Biology"
] | 48 | [
"Fungi",
"Fungus species"
] |
11,127,975 | https://en.wikipedia.org/wiki/Leucocytospora%20leucostoma | Leucocytospora leucostoma is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Diaporthales
Fungal plant pathogens and diseases
Fungus species | Leucocytospora leucostoma | [
"Biology"
] | 42 | [
"Fungi",
"Fungus species"
] |
11,127,982 | https://en.wikipedia.org/wiki/Leveillula%20taurica | Leveillula taurica is an obligate fungal pathogen, from the phylum Ascomycota, which causes powdery mildew on onion. This disease prefers warm, dry environments. It is rare in the United States, and is currently restricted to western states. Globally, it is also a minor problem with limited occurrences in the Middle East, Europe, and South America. L. taurica causes powdery mildew of onions, but is also known to infect other allium, solanaceous, and cucurbit species. The disease has appeared in parts of the Middle East, the Mediterranean, and South and North America. Currently, it is not a cause for major concern in the U.S. and throughout the world, as its geographic extent is sparse. In addition, it is relatively easy to control through basic sanitation and reducing water stress.
Hosts and symptoms
L. taurica is the pathogen responsible for powdery mildew on onions, but it can also infect peppers, tomatoes, eggplant, cotton, and garlic. While L. taurica can infect many different plants it is actually very host specific. Different races of L. taurica can only infect certain crops, and even specific cultivars within the same crop. An accurate way to describe its host specificity is that this disease is, “a composite species consisting of many host-specific races." Symptoms of Onion Powdery Mildew (OPM) are usually seen as circular or oblong lesions that are 5 to 20 mm and have a chlorotic or necrotic appearance. The lesions appear on older leaves before the bulb of the onion begins to form, but also can occur on the younger leaves towards the end of the season. As the disease progresses signs of OPM can also be seen. On the lesions white mycelium can be found with conidiophores bearing either lanceolate or rounded condia.
Disease cycle
The polycyclic disease cycle of L. taurica is similar to that of other powdery mildew species. It overwinters (as chasmothecia) in crop residues above the soil surface. Under favorable climatic conditions, the chasmothecia open and release ascospores, which are wind-dispersed. The ascospores enter the host through its stomata, germinate, and colonize the host’s tissues with its mycelia. The pathogen then begins to produce its asexual conidia, either singly or on branched conidiophores. The conidia exit through the host’s stomata and serve as a secondary inoculum to spread disease after initial infection. In the fall, the pathogen undergoes sexual reproduction and again produces chasmothecia, its dormant, overwintering structure.
Environment
The genus Leveillula is distributed in warm, arid areas of Africa, Asia, South America, southern Europe, and the western parts of North America. Species within the genus are adapted to xerophytic conditions, exemplified by the ability of their conidia to germinate rapidly and at any relative humidity.
L. taurica is primarily a disease of allium species—it has been documented on onions and garlic in Israel and southeastern Europe—but can also infect other species, including cucumbers, peppers, eggplants and tomatoes. It was first reported in the western United States in 1985, infecting onions in the state of California. It has since appeared in Idaho, the state of Washington, and Utah.
Management
OPM tends to appear near the end of the growing season. The best way to control L. taurica is to remove all crop residue from the previous onion crop before subsequent planting. Two methods to accomplish this include deep tillage, and rotating to a non-host crop the year following an onion crop. Controlling volunteer onion sprouting (or the emergence of the previous year's onion plants) will also assist in prevention of the pathogen from carrying-over from one year to the next.
Irrigation practices can also be used to limit the development of OPM. Moisture stress has been noted to increase the susceptibility of host species to L. taurica. Onions with adequate moisture will be more resistant to the pathogen, and onion crops with overhead irrigation rarely see powdery mildew development in the field.
The fungicide Cabrio (produced by BASF Chemical) is labeled for the control of L. taurica on onions, but the disease rarely progresses enough to justify the use of a fungicide. Considerations of economic benefit should be made before the fungicide is applied, and all labeling directions followed.
Resistant varieties have been found in some studies, Jahn et al. found powdery mildew resistance to be extremely beneficial in cucurbits, reducing the need for fungicide, and reducing agricultural losses due to powdery mildew pathogens. Although a truly resistant variety has not been found for onion plants, some onion genotypes with glossy leaves had selective susceptibility to L. taurica. Onions with the glossiest leaves were found to be most susceptible, while onions with less glossy leaves showed limited susceptibility. However, the study was unable to come to a conclusion on which variety was best suited for L. taurica resistance.
Importance
The economic importance of OPM is limited, as the disease is sporadic, and it rarely progresses enough to make fungicide treatment necessary. Because of the limited importance of OPM, data on incidence rates are not well documented. Simple cultural controls, as mentioned above, are usually effective in controlling losses associated with the disease. The disease geography within the United States is limited to Idaho, Utah, California, and the Pacific Northwest. Findings have also occurred in Israel, Italy, Iran, Sudan, Brazil, and Southeastern Europe.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Vegetable diseases
Cotton diseases
Fungi described in 1851
Leotiomycetes
Taxa named by Joseph-Henri Léveillé
Fungus species | Leveillula taurica | [
"Biology"
] | 1,231 | [
"Fungi",
"Fungus species"
] |
11,127,998 | https://en.wikipedia.org/wiki/Linochora%20graminis | Linochora graminis is a fungal plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Phyllachorales
Fungal plant pathogens and diseases
Fungus species | Linochora graminis | [
"Biology"
] | 40 | [
"Fungi",
"Fungus species"
] |
11,128,003 | https://en.wikipedia.org/wiki/Macrophomina%20phaseolina | Macrophomina phaseolina is a Botryosphaeriaceae plant pathogen fungus that causes damping off, seedling blight, collar rot, stem rot, charcoal rot, basal stem rot, and root rot on many plant species.
Hosts, symptoms, and signs
One of the most harmful seed and soil borne pathogens, Macrophomina phaseolina is a fungus that infects nearly 500 plant species in more than 100 families. The hosts include: peanut, cabbage, pepper, chickpea, soybean, sunflower, sweet potato, alfalfa, sesame, potato, sorghum, wheat, and corn, among others. The identification of isolates of M. phaseolina is usually based on morphology and efforts to divide the pathogen into subspecies, but because there are wide intraspecific variations in the phenotype of the isolates, these criteria are often not reliable. The failure to correctly detect and identify M. phaseolina using conventional culture-based morphological techniques has led scientists to develop nucleic acid-based molecular approaches, such as highly sensitive and specific polymerase chain reaction-based methods. Researchers have also recently created species-specific oligonucleotide primers and digoxigenin-labeled probes in hopes of better identifying and detecting M. phaseolina.
The pathogen M. phaseolina affects the fibrovascular system of the roots and basal internodes of its host, impeding the transport of water and nutrients to the upper parts of the plant. As a result, progressive wilting, premature dying, loss of vigor, and reduced yield are characteristic symptoms of M. phaseolina infection. The fungus also causes many diseases like damping off, seedling blight, collar rot, stem rot, charcoal rot, basal stem rot, and root rot. Although brown lesions may form on the hypocotyls or emerging seedlings, many symptoms occur during or after flowering, including grey discoloration of the stem and taproots, shredding of plant tissue in the stem and top of the taproot, and hollowing of the stem. Small black dots may form beneath the epidermis of the lower stem and in the taproot, giving the stems and roots a charcoal-sprinkled appearance. When the epidermis is removed, small and black microsclerotia (a sign of the disease) may be so numerous that they give a greyish-black tint to the plant tissue. In addition, reddish-brown discoloration and black streaks can form in the pith and vascular tissues of the root and stem.
Disease cycle
Macrophomina phaseolina has a monocyclic disease cycle.
Survival
The M. phaseolina fungus has aggregates of hyphal cells, which form microsclerotia within the taproots and stems of the host plants. The microsclerotia overwinter in the soil and crop residue and are the primary source of inoculum in the spring. They have been shown to survive in the soil for up to three years. They are black, spherical or oblong structures that allow the persistence of the fungus under poor conditions, such as low soil nutrient levels and temperatures above 30 C. However, in wet soils, microsclerotia survival is significantly lower, often surviving no more than 7 to 8 weeks, and mycelium cannot survive more than 7 days. Additionally, infected seeds can carry the fungus in their seed coats. These infected seeds either do not germinate or produce seedlings that die soon after emergence.
Infection
Macrophomina phaseolina is a heat- and drought-favoring disease, producing large quantities of microsclerotia under relatively low water potentials and relatively high temperatures. In soybeans especially, charcoal rot typically occurs when the plants are experiencing significant drought stress.
When conditions are favorable, hyphae germinate from these microsclerotia. Germination of the microsclerotia occurs throughout the growing season when temperatures are between 28 and 35 C. Microsclerotia germinate on the roots' surface, and germ tubes on the end of the microsclerotia form appresoria that penetrate the hosts' epidermal cell walls using turgor pressure or through natural openings.
The hyphae infect the roots of the host plant. Initially, the hyphae enter the cortical tissue and grow intercellularly, then infect the roots and the vascular tissue. Within the vascular tissue, mycelia and sclerotia are produced and plug the vessels. This causes the greyish-black color often observed in plants infected by M. phaseolina, and it also prevents water and nutrients from being transported from the roots to the upper parts of the plant. Thus, due to this systemic infection, diseased plants often wilt and die prematurely.
Management
Understanding the monocyclic disease cycle of M. phaseolina can help plant pathologists better understand the pathogen itself, it can help horticulturalists develop disease-resistant crops, and it can help farmers understand at what point during the growing cycle to apply fungicides or implement other management techniques.
There are several techniques currently used to manage M. phaseolina fungal infections. Often, fungicides are used to inhibit mycelial growth. These include thiram, iprodione, carbendazim, pyraclostrobin, fluquinconazol, tolyfluanid, and metalaxyl and penflufen + trifloxystrobin. The active ingredients carbendazim and penflufen + trifloxystrobin were shown to be the most powerful to control M. phaseolina. In this same study, the M. phaseolina isolate showed insensitivity to the active ingredients fluquinconazole, metalaxyl, thiram and tolyfluanid. Thus, fungicides are not necessarily an effective way to manage this fungal pathogen.
However, there are alternatives to fungicides that are especially preferred by organic farmers, such as a combination of soil solarization and organic amendment. Soil solarization is a method of using solar power for controlling pathogens in the soil by mulching the soil and covering it with a large, usually transparent polyethylene tarp to trap solar energy and heat the soil. In studies, this method has proven to be as effective as fungicides. Additionally, crop rotation can be an effective management practice. According to researchers, "Rotation out of soybeans for three years may effectively reduce microsclerotia numbers and is useful for managing charcoal rot" because "corn is not as good of a host to M. phaseolina as soybean so rotation with corn for three years may help reduce populations but not eliminate the pathogen from the soil." Finally, tillage practices can reduce moisture in the soil and make the environment less favorable for the pathogen.
Human infection
This organism has been reported to cause infection in humans, particularly in immunosuppressed patients. The infection may present as a cutaneous cellulitis or as an ocular keratitis.
References
Fungal conifer pathogens and diseases
Maize diseases
Botryosphaeriaceae
Fungi described in 1947
Soybean diseases
Fungus species | Macrophomina phaseolina | [
"Biology"
] | 1,511 | [
"Fungi",
"Fungus species"
] |
11,128,010 | https://en.wikipedia.org/wiki/Massarina%20walkeri | Massarina walkeri is a plant pathogen fungi. It attacks medicago sativa and has been found in Queensland, Australia.
References
External links
Index Fungorum
USDA ARS Fungal Database
Pleosporales
Fungal plant pathogens and diseases
Fungi described in 1987
Fungus species | Massarina walkeri | [
"Biology"
] | 57 | [
"Fungi",
"Fungus species"
] |
11,128,015 | https://en.wikipedia.org/wiki/Monochaetia%20mali | Monochaetia mali is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Xylariales
Fungi described in 1902
Taxa named by Benjamin Matlack Everhart
Fungus species | Monochaetia mali | [
"Biology"
] | 49 | [
"Fungi",
"Fungus species"
] |
11,128,028 | https://en.wikipedia.org/wiki/Mucor%20piriformis | Mucor piriformis is a plant pathogen that causes a soft rot of several fruits known as Mucor rot. Infection of its host fruits, such as apples and pears, takes place post-harvest. The fungi can also infect citrus fruits.
References
External links
Index Fungorum
USDA ARS Fungal Database
Mucor Rot - post-harvest diseases of apples and pears
Mucoraceae
Fungal plant pathogens and diseases
Apple tree diseases
Pear tree diseases
Fungi described in 1772
Fungus species | Mucor piriformis | [
"Biology"
] | 100 | [
"Fungi",
"Fungus species"
] |
11,128,038 | https://en.wikipedia.org/wiki/Mycena%20citricolor | Mycena citricolor is a species of mushroom-forming fungus in the family Mycenaceae. It is a plant pathogen producing leaf spots on coffee plants. This fungus causes the disease commonly known as American Leaf Spot. Mycena citricolor affects coffee plants, primarily in Latin America, but can grow on other plants as well. This fungus can grow on all parts of the coffee plant including the leaves, stems and fruits. When grown on the leaves, Mycena citricolor results in leaves with holes that often fall from the plant.
Description
The Mycena fungus can be identified growing on somewhat circular, brown spots on coffee leaves. The brown spots are caused by the presence of the parasitic fungus and by looking at the leaves closely, small mushrooms with luminescence can be seen. The fungi's luminescence is active in the presence and absence of light. Its luminescence is also affected by the temperature of its environment.
See also
List of bioluminescent fungi
References
citricolor
Fungi described in 1868
Bioluminescent fungi
Fungal plant pathogens and diseases
Taxa named by Miles Joseph Berkeley
Taxa named by Moses Ashley Curtis
Fungus species | Mycena citricolor | [
"Biology"
] | 244 | [
"Fungi",
"Fungus species"
] |
11,128,043 | https://en.wikipedia.org/wiki/Mycoleptodiscus%20terrestris | Mycoleptodiscus terrestris is a fungal plant pathogen.
Host and symptoms
Mycoleptodiscus terrestris is an ascomycete with a wide host range that includes several types of popular aquatic weeds that have become invasive in their problem states – mainly southern states. But aside from them the pathogen also infects several types of alfalfa and legumes and have been seen to infect plants all the way up to Minnesota. This disease is known to cause several symptoms in affected hosts including: leaf spot, crowning, and lots of root rot. These symptoms are what cause major yield loss and is why this pathogen is so important to our agricultural systems.
Importance
This pathogen affects a large amount of very important crops from our legume families to the less important crops in other countries that don't support the economy. In America the crops of interest are the legumes and alfalfa we grow, but in other countries like Asia and Australia it affects a wider range like some Lotuses, Psium, and fabaceae just to name a few. What is truly important about this pathogen is that it has been studied since the 1970s in order for it to be used as a viable control of aquatic weeds like watermilfoil that is invasive in warmer wet regions of America. What has been found is that it can and will infect these pest plants and could be used as a viable control since they cause plant killing symptoms in target plants after being treated with just some hyphae and fungal material in the water.
Disease cycle
The disease cycle of Mycoleptodiscus terrestris is very dependent on it being able to spread its sclerotia. This pathogen mainly overwinters in these strong structures which then begin to affect the next year's crop in the form of damping off or late germination infection which targets the roots and stem first of the young plants. In fact the sclerotia of this pathogen are so highly developed and sturdy that they are collected as the inoculum in many experiments involving the pathogen and they are often viable through several different conditions including different levels of moisture and temperature. They can often be collected and dried chemically and they will still be viable for inoculation or study.
See also
List of soybean diseases
References
Magnaporthales
Fungal plant pathogens and diseases
Fungi described in 1953
Soybean diseases
Fungus species | Mycoleptodiscus terrestris | [
"Biology"
] | 492 | [
"Fungi",
"Fungus species"
] |
11,128,048 | https://en.wikipedia.org/wiki/Mycosphaerella%20areola | Mycosphaerella areola is a plant pathogen infecting cotton.
See also
List of Mycosphaerella species
References
areola
Fungi described in 1932
Cotton diseases
Fungal plant pathogens and diseases
Fungus species | Mycosphaerella areola | [
"Biology"
] | 45 | [
"Fungi",
"Fungus species"
] |
11,128,057 | https://en.wikipedia.org/wiki/Zymoseptoria%20tritici | Zymoseptoria tritici, synonyms Septoria tritici, Mycosphaerella graminicola, is a species of filamentous fungus, an ascomycete in the family Mycosphaerellaceae. It is a wheat plant pathogen causing septoria leaf blotch that is difficult to control due to resistance to multiple fungicides. The pathogen today causes one of the most important diseases of wheat.
In 2011, Quaedvlieg et al. introduced a new combination for this species: Zymoseptoria tritici, as they found that the type strains of both the genus Mycosphaerella (linked to the anamorph genus Ramularia) and the genus Septoria (linked to the genus Septoria, an extensive clade of very distinct septoria-like species within the Mycosphaerellaceae) clustered separately from the clade containing both Zymoseptoria tritici and Z. passerinii. Since 2011, a total of eight Zymoseptoria species have been described within the genus Zymoseptoria; Z. tritici (the type of the genus Zymoseptoria), Z. pseudotritici, Z. ardabiliae, Z. brevis, Z. passerinii, Z. halophila, Z. crescenta and Z. verkleyi (Named after Gerard J.M. Verkleij, for the contribution that he has made to further the understanding of the genus Septoria).
Description
This fungus causes septoria tritici blotch of wheat, a disease characterized by necrotic blotches on the foliage. These blotches contain asexual (pycnidia) and sexual (pseudothecia) fructifications.
Asexual state (anamorph, asexual stage was previously named as Septoria tritici): Pycnidiospores are hyaline and threadlike and measure 1.7-3.4 x 39-86 μm, with 3 to 7 indistinct septations. Germiniation of pycnidiospores can be lateral or terminal. Cirrhi are milky white to buff. Sometimes in culture nonseptate, hyaline microspores, measuring 1-1.3 × 5-9 μm, occur outside pycnidia by yeastlike budding.
Sexual state (teleomorph): Pseudothecia are subepidermal, globose, dark brown, and 68-114 μm in diameter. Asci measure 11-14 × 30-40 μm. Ascospores are hyaline, elliptical, and 2.5-4 × 9-16 μm, with two cells of unequal length.
Genetics
Zymoseptoria tritici represents an intriguing model for fundamental genetic studies of plant-pathogenic fungi. It is haploid plant-pathogenic fungus. Many fungi are haploid, which greatly simplifies genetic studies.
Zymoseptoria tritici was the first species, in 2002, of the family Mycosphaerellaceae to have a linkage map created.
The first report of fully sequenced genome of Zymoseptoria tritici from 2011 was the first genome of a filamentous fungus to be finished according to current standards. The length of the genome is 39.7 Mb, that is similar to other filamentous ascomycetes. The genome contains 21 chromosomes, that is the highest number reported among ascomycetes. Furthermore, these chromosomes have an extraordinary size range, varying from 0.39 to 6.09 Mb.
A striking aspect of Zymoseptoria tritici genetics is the presence of many dispensable chromosomes. Eight of chromosomes could be lost with no visible effect on the fungus and thus are dispensable. Dispensable chromosomes have been found in other fungi but they usually occur at a low frequency and typically represent single or a few chromosomes. Dispensable chromosomes have originated by ancient horizontal transfer from an unknown donor, that was followed by extensive genetic recombination, a possible mechanism of stealth pathogenicity and exciting new aspects of genome structure.
A surprising feature of the Zymoseptoria tritici genome compared to other sequenced plant pathogens was that it contained very few genes for enzymes that break down plant cell walls, which was more similar to endophytes than to pathogens. Goodwin et al. (2011) suggested, that the stealth pathogenesis of Zymoseptoria tritici probably involves degradation of proteins rather than carbohydrates to evade host defenses during the biotrophic stage of infection and may have evolved from endophytic ancestors.
Evolution
The fungus Zymoseptoria tritici has been a pathogen of wheat since host domestication 10,000–12,000 years ago in the Fertile Crescent. The wheat-infecting lineage emerged from closely related Mycosphaerella pathogens infecting wild grasses. It has coevolved and spread with its host globally. Zymoseptoria tritici shows a significantly higher degree of host specificity and virulence in a detached leaf assay.
The emergence and "co-domestication" of Zymoseptoria tritici was associated with an adaptation to wheat and an agricultural environment. Endemic descendants of the progenitor of Zymoseptoria tritici are still found on wild grasses in the Middle East; however these "wild" pathogens show a broader host range than the "domesticated" wheat pathogen. The closest known relative of Zymoseptoria tritici is named Z. pseudotritici B. Zymoseptoria pseudotritici was isolated in Iran from the two grass species Agropyron repens and Dactylis glomerata growing in close proximity to fields planted to bread wheat (Triticum aestivum). Although Z. tritici is a frequent pathogen of wheat in Iran, no evidence of gene flow between Z. pseudotritici and Z. tritici was detected based on sequence analysis of six nuclear loci.
Life cycle
Zymoseptoria tritici overwinters as fruiting bodies on crop debris, mostly as pseudothecia (sexual fruiting bodies) but sometimes also some pycnidia (asexual fruiting bodies). The sexual spores are quantitatively the more significant spores involved in primary inoculum of the disease, while the asexual spores are more significant in the secondary cycle. In early spring, ascospores, the sexual spores of the fungus, are released from the pseudothecia. Ascospores are wind-dispersed and eventually land on the leaves of a host plant (bread wheat or durum wheat). Unlike most other plant pathogens, Zymoseptoria tritici uses a germ tube to enter the host leaf through stomata rather than by direct penetration. There is a long latent period of up to two weeks following infection before symptoms develop. The fungus evades host defenses during the latent phase, followed by a rapid switch to necrotrophy immediately prior to symptom expression 12–20 days after penetration. The period between infection and formation of sporulating structures (latent period) was estimated to be 20.35 ± 4.15 days for Zymoseptoria tritici in Northern Germany and decreased with increasing temperature. Such a switch from biotrophic to necrotrophic growth at the end of a long latent period is an unusual characteristic shared by most fungi in the genus Mycosphaerella. Very little is known about the cause or mechanism of this lifestyle switch even though Mycosphaerella is one of the largest and most economically important genera of plant-pathogenic fungi.
Primary inoculum requires wet conditions and cool temperatures of 50-68 °F. Under appropriate environmental conditions, lesions are able to develop on infected leaves, and soon pycnidia begin to develop on the lesions. The pycnidia appear as small dark dots on the lesions. From the pycnidia, conidiospores, the asexual spores of the fungus, are released. These asexual spores are dispersed via rain splash and are response for the secondary inoculum of this polycyclic disease cycle. When the conidiospores are splashed onto leaves, they act similarly to ascospores and cause the development of foliar lesions. In addition to pycnidia, pseudothecia also develop within these lesions. Pycnidia and pseudothecia are the structures in which the fungus overwinters, and the cycle begins again.
Disease Management
Zymoseptoria tritici is a difficult fungus to control because populations contain extremely high levels of genetic variability and it has very unusual biology for a pathogen. Z. tritici has an active sexual cycle under natural conditions, which is an important driver of septoria tritici blotch epidemics and results in high genetic diversity of populations in the field.
The most effective, economical, and simple method of Z. tritici management is planting resistant cultivars. Twenty-one resistant genes have been named, mapped, and published. Mikaberidze and McDonald 2020 found a fitness tradeoff between genes for Septoria tolerance and Septoria resistance in wheat. Some cultivars are resistant in one region but susceptible in another; it depends on the local pathogen population. All varieties of bread wheat and durum wheat are susceptible to the disease to some extent, but planting varieties that have at least partial resistance to the local population of Zymoseptoria tritici can greatly improve yield.
There are also cultural management strategies that may be effective, including regular rotation of crops, deep plowing, and late planting. More specifically, rotating a recently infected field to any non-host crop can be useful in minimizing the amount of fungus present in the field. Planting winter wheat after the first ascospore flights in September is a way to reduce primary inoculum of winter wheat.
Fungicide use often simply is not economical for Septoria Leaf Blotch. The rapid evolution of pathogen resistance to fungicides is a major barrier. Zymoseptoria tritici has resistance to multiple fungicides, because it has number of substitutions of CYP51. CYP51 substitutions include Y137F which confers resistance to triadimenol, I381V which confers resistance to tebuconazole and V136A that confers resistance to prochloraz. Chemical control of the pathogen (using fungicides) now relies on the application of SDHIs, azole fungicides which are demethylase inhibitors that inhibit lanosterol 14 alpha-demethylase (CYP51) activity.
The last method of control for Zymoseptoria tritici is biological control using bacteria. Bacillus megaterium has been shown to cause about an 80% decrease in disease development in the trials done so far. Pseudomonads are also a promising bacterial control option. A benefit to using pseudomonads or bacillus is that they are not harmed by most fungicides, so they can be used in combination with chemical controls. However, a lack of commercial availability limits the use of biological controls.
Disease Importance
The ascomycete fungus Zymoseptoria tritici causes septoria tritici blotch, a foliar disease of wheat that poses a significant threat to global food production. It is the primary foliar disease of winter wheat in most western European countries. Zymoseptoria tritici infects wheat crops throughout the world and is also currently a big problem in Iran, Tunisia, and Morocco. Severe epidemics of the disease have decreased wheat yields by 35-50%. In the United States, Septoria leaf blotch is a very important disease in wheat, second only to wheat rust. An estimated $275 million is lost per year in the US due to this disease. In Europe the annual losses are equivalent to over 400 million USD.
Different areas of the world are currently trying different management strategies. For example, in the Nordic-Baltic region, one of the largest wheat-producing regions of the world, the use of fungicides has substantially increased wheat yields. The fungicides that have been shown to be effective include quinone outside inhibitors (QoIs), which, like most fungicides, are expensive to apply in large quantities. As climate change begins to increase temperatures around the globe, Zymoseptoria tritici, along with many other fungal pathogens, is likely to show increased overwintering survival and therefore more substantial primary inocula. The need for effective management techniques will become even more important as the prevalence of Septoria leaf blotch increases with climate change.
References
This article incorporates CC-BY-2.5 text from references
External links
USDA ARS Fungal Database
Orton E. S., Sian Deller S. & Brown J. K. M. (2011). "Mycosphaerella graminicola: from genomics to disease control". Molecular Plant Pathology 12(5): 413-424. .
Mycosphaerellaceae
Fungal plant pathogens and diseases
Wheat diseases
Fungi described in 1842
Taxa named by John Baptiste Henri Joseph Desmazières
Fungus species | Zymoseptoria tritici | [
"Biology"
] | 2,813 | [
"Fungi",
"Fungus species"
] |
11,128,064 | https://en.wikipedia.org/wiki/Sclerotinia%20borealis | Sclerotinia borealis or snow scald is a psychrophilic necrotrophic plant pathogen with wide host range, including crop plants, such as barley, rye and wheat, and thus causing much economical damage.
Physiology
Temperature
Minimum growth temperature is below . Optimal growth range is . Maximum growth temperature , whereupon irregular mycelial growth occurs and oxygen consumption is far above healthy level; does not survive above. Sclerotia germination optimal at four weeks of daily thermal cycles of followed by . Frost is necessary during life cycle.
Enzymes
Produces polygalacturonase; variant with maximum activity between and only 30% of max activity at . Activity preserved at beyond two years, but inactivated by overnight at room temperature, or by 30 minutes of . A crude extract of cultured bran contained a particular low mass molecule which maintained activity at low temperature.
Antifreeze proteins
Necessitated by its lifestyle, S. borealis produces its own antifreeze proteins. One of these is homologous to Atlantic winter flounder type I antifreeze protein. Extracellular presence of its AFPs is not necessary.
Life cycle
Upon the spring snowmelt, wet leaves develop S. borealis growth. Sclerotia and mycelia grow on sheaths, crowns, surfaces, and interiors of leaves. It has dramatically more growth – and damage to its hosts – in growth seasons following winters with greater depth of soil freezing but less snow cover. S. borealis is very soil-frost-dependent.
Morphology
Sclerotia are long and wide when formed (i.e. before desiccation).
Apothecia cup-shaped pale yellow to pale brown, cup diameter , stalks high.
Mycelia gray.
Hosts
Grasses and trees. Economically significant grasses include winter cereals and forages. Conifer seedlings in the Volga and Ural regions Russia.
Distribution
S. borealis is found in cool temperate areas, frigid zone areas and into the Arctic, including northern Japan, Russia (Siberia, middle course of Volga, Ural, Russian Far East), northern Scandinavia, and North America. Specifically including Arctic areas of Alaska, the Yukon, Greenland, Finnmark county in Norway, Finnish Lapland, Swedish Lapland, Svalbard. It was unexpectedly not found in the similar climate of Iceland. Southernmost limit is Iwate, northern Japan, the Altai Mountains in central Siberia, and possibly the Xinjiang Province of China. Not found in any temperate region which also receives snowfall, except Japan.
Laboratory culture
Lab culture must simulate the freezing cycle of the natural range. Can grow on relatively low water potato dextrose agar if twice the normal PDA concentration, sucrose, KCl, and -mannitol. Higher mycelial growth and lower optimal mycelial growth temp (to ) if increased intracellular osmosis. Able to utilize nutrients from partially thawed low-water PDA. Vegetative hyphae do not accumulate sclerotinial proteins when cultured at but do at , and mycelial proteins cultured at are decreased by switch to incubation at . These may be the/one of the reasons for irregular growth, progressing to lethality, at these higher temperatures.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Barley diseases
Rye diseases
Wheat diseases
Sclerotiniaceae
Fungi described in 1917
Fungus species | Sclerotinia borealis | [
"Biology"
] | 700 | [
"Fungi",
"Fungus species"
] |
11,128,069 | https://en.wikipedia.org/wiki/Myrothecium%20roridum | Myrothecium roridum is a fungal plant pathogen. Myrotoxin B has been isolated from it.
References
Fungal plant pathogens and diseases
Stachybotryaceae
Fungi described in 1790
Fungus species | Myrothecium roridum | [
"Biology"
] | 46 | [
"Fungi",
"Fungus species"
] |
11,128,077 | https://en.wikipedia.org/wiki/Myrothecium%20verrucaria | Myrothecium verrucaria is a species of fungus in the order Hypocreales. A plant pathogen, it is common throughout the world, often found on materials such as paper, textiles, canvas and cotton. It is a highly potent cellulose decomposer.
It has been formulated into a biopesticide for control of nematodes and weeds. The pesticide's active ingredient is a mixture of the killed fungus, M. verrucaria, and the liquid in which the fungus was grown. The dead fungus kills specific parasitic microscopic pests called nematodes, which attack plants, usually through their roots. The active ingredient is specific, being effective only against nematodes that parasitize plants; it does not harm free-living nematodes. Because the mixture may be toxic to aquatic organisms, it is not approved for use in or near bodies of water.
Since 1998, the United States Department of Agriculture, Agricultural Research Service (ARS) has experimented with using M. verrucaria as a biologically based herbicide against kudzu vines. A spray based on M. verrucaria works under a variety of conditions (including the absence of dew), causes minimal injury to many of the other woody plants in kudzu-infested habitats, and takes effect fast enough that kudzu treated with it in the morning starts showing evidence of damage by mid-afternoon. Initial formulations of the herbicide produced toxic levels of trichothecene as a byproduct, though the ARS discovered that growing M. verrucaria in a fermenter on a liquid instead of a solid diet limited or eliminated the problem.
See also
Diacetylverrucarol
References
Fungi described in 1805
Fungal plant pathogens and diseases
Stachybotryaceae
Taxa named by Lewis David de Schweinitz
Taxa named by Johannes Baptista von Albertini
Fungus species | Myrothecium verrucaria | [
"Biology"
] | 398 | [
"Fungi",
"Fungus species"
] |
11,128,108 | https://en.wikipedia.org/wiki/Oidiopsis%20gossypii | Oidiopsis gossypii is a plant pathogen.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Erysiphales
Fungus species
Fungi described in 1920 | Oidiopsis gossypii | [
"Biology"
] | 43 | [
"Fungi",
"Fungus species"
] |
11,128,111 | https://en.wikipedia.org/wiki/Podosphaera%20tridactyla | Podosphaera tridactyla is a plant pathogen infecting almonds.
References
Fungal tree pathogens and diseases
Fruit tree diseases
tridactyla
Fungi described in 1833
Fungus species | Podosphaera tridactyla | [
"Biology"
] | 40 | [
"Fungi",
"Fungus species"
] |
11,128,117 | https://en.wikipedia.org/wiki/Olpidium%20brassicae | Olpidium brassicae is a plant pathogen, it is a fungal obligate parasite. In 1983, the Alsike, Alberta area's clover (which is a major part of horses' diet) was struck by a fungus epidemic of Olpidium brassicae, previously not seen in Canada.
Vector
O. brassicae is the fungal vector for most, if not all, necroviruses.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Plant pathogens and diseases by vector
Chytridiomycota
Fungi described in 1878
Fungus species | Olpidium brassicae | [
"Biology"
] | 125 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
11,128,134 | https://en.wikipedia.org/wiki/Penicillium%20expansum | Penicillium expansum is a psychrophilic blue mold that is common throughout the world in soil. It causes Blue Mold of apples, one of the most prevalent and economically damaging post-harvest diseases of apples.
Though primarily known as a disease of apples, this plant pathogen can infect a wide range of hosts, including pears, strawberries, tomatoes, corn, and rice. Penicillium expansum produces the carcinogenic metabolite patulin, a neurotoxin that is harmful when consumed. Patulin is produced by the fungus as a virulence factor as it infects the host. Patulin levels in foods are regulated by the governments of many developed countries. Patulin is a particular health concern for young children, who are often heavy consumers of apple products. The fungus can also produce the mycotoxin citrinin.
Hosts and disease development
Penicillium expansum has a wide host range, causing similar symptoms on fruits which include apples, pears, cherries, and citrus . Initial infection most often occurs at sites of fruit injury, such as bruises or puncture wounds. Although infections may start in the field, infected spots often become evident post-harvest, and expand while fruit is in storage. Infected areas are clearly delineated and light brown, and soft decaying tissue can be easily "scooped" out of the surrounding healthy tissue.,
Spore masses later appear on the surfaces of infected fruit, initially appearing as white mycelium, then turning blue to blue-green in color as the asexual spores mature. Fruit affected by P. expansum typically has an earthy, musty odor. Lesions measure 1–1.25 inches in diameter eight to ten weeks after infection if kept under cold storage conditions. Age factors into P. expansum infection, in that overripe or mature fruits are most susceptible to infection, while those picked underripe are less likely to become infected.
In apples, the colors of the lesions may vary with variety, from lighter-brown on green and yellow apple varieties to dark-brown on the deeper-red and other darker-color varieties. Varieties particularly susceptible to P. expansum infection include McIntosh, Golden Supreme, and Golden Delicious.
Both sweet and sour cherries are affected by P. expansum. Cherry varieties found to be particularly susceptible to P. expansum infection were mainly early varieties, including Navalinda and Burlat.
Diagnosis
Penicillium expansum can be identified by its morphological characteristics and secondary metabolites in fruit or in axenic culture. The presence of the secondary metabolite patulin can suggest P. expansum infection, but this method is not species-specific as a number of different Penicillium species and their allies produce patulin. Patulin presence can be assayed using high-performance liquid chromatography with ultraviolet detection. Molecular methods based on species-specific genes can speed identification.
Environment
Penicillium expansum grows best in wet, cool (<25C) conditions. P. expansum was found to grow most efficiently in a temperature range of 15–27 degrees Celsius, with slower growth at lower and higher temperatures. P. expansum grows best in wet conditions; growth rate was fastest at a relative humidity of 90%. P. expansum infection acidifies host tissues via the secretion of organic acids, and that acidification enhances fungal development, indicating a link between environmental acidity and P. expansum virulence.
Disease cycle
P. expansum infects a fruit via wounds through which the conidia are able to enter. Usually, puncturing, bruising, and limb rubs occur during harvesting, packaging, and processing of the fruit, all of which provide sites through which spores can enter the fruit. Conidia can be found in soil, decaying debris, and tree bark, and can survive cold temperatures. Conidia may be isolated from the air of the orchard and packaging house, on the walls of the packaging houses, and from the water and fungicide solution into which harvested fruits are dunked before packaging or storage. Exposure to conidia at any step of growth, harvesting, processing, shipping, and storage can lead to inoculation and disease. Conidia that have gained access via a wound can germinate to form a germ tube. This germ tube will continue to grow as hyphae which colonize the fruit, killing fruit cells in an expanding infection.
If the fungus has colonized the fruit with mycelium, the formation of conidiophores occurs on the surface or subsurface of the hyphae. The conidiophores are mostly smooth-walled terverticillate penicilli. A terverticillate pencilii has multiple branch points below the phialides, the cells that the conidia are attached to. However, at times, the penicilli may be rough or biverticillate (only two levels of branching). The phialides are packed close together with nearly a cylindrical shape. The conidia are dry, smooth, elliptical, and "dull-green" in color and are often disseminated by wind currents.
Sexual reproduction has not been observed in nature for P. expansum.
Management
Due to the susceptibility to infection of mature and overripe fruit, post-harvest treatment of fruit with fungicides is the most common method of combating P. expansum. Proper sanitation and careful handling of the fruit are two non-chemical methods that can help control the disease. Good sanitation reduces contact with orchard soil either on the fruit or in transportation containers. And since the fungus needs a wound to infect, careful handling can reduce infection even when the fungus is present. Chemical treatment with a chlorine bath can be effective in killing spores. Biofungicides using active ingredients such as bacteria and yeast have been successful in preventing infection but are ineffective against existing infections.
Importance
Penicillium expansum produces the mycotoxin patulin, a neurotoxin that can enter the food supply via apples and apple products such as juice and cider. Considering the size of the apple product industry and the large number of people that may come into contact with infected fruits, control of P. expansum is vitally important.
References
External links
USDA ARS Fungal Database
Food microbiology
Fungal plant pathogens and diseases
Apple tree diseases
expansum
Taxa named by Johann Heinrich Friedrich Link
Fungi described in 1809
Fungus species | Penicillium expansum | [
"Biology"
] | 1,351 | [
"Fungi",
"Fungus species"
] |
11,128,138 | https://en.wikipedia.org/wiki/Peniophora%20sacrata | Peniophora sacrata is a species of fungus in the family Peniophoraceae. A plant pathogen, the fungus causes Peniophora root and stem canker on apple trees.
See also
List of apple diseases
References
Fungi described in 1955
Fungi of New Zealand
Fungal tree pathogens and diseases
Apple tree diseases
Russulales
Taxa named by Gordon Herriot Cunningham
Fungus species | Peniophora sacrata | [
"Biology"
] | 78 | [
"Fungi",
"Fungus species"
] |
11,128,155 | https://en.wikipedia.org/wiki/Peronospora%20trifoliorum | Peronospora trifoliorum, commonly known as downy mildew of alfalfa, is an oomycete plant pathogen infecting alfalfa.
Hosts and symptoms
Peronospora trifoliorum commonly infects numerous strains and varieties of alfalfa. On alfalfa, the primary symptoms of Peronospora trifoliorum are chlorotic leaf blotches that range from light green to yellow-green to gray-green; rolled or downturned leaves; and thickened, stunted stems ending in rosette-like growths. The main method of identifying the disease is by the moldy, downy growth on the underside of leaves that appears white, gray, or light purple as this is a diagnostic sign of downy mildew of alfalfa (Davis, Frate, and Putnam, 2017). Only seedlings and young tissue are susceptible to infection which, with proper cultural controls, can limit the development and progression of the disease. There is also the potential for secondary infection, which can occur every five days during ideal conditions (Goldberg, 2000).
Peronospora trifoliorum has been reported from Trifolium repens but it is uncommon.
Environment
Peronospora trifoliorum prefers high humidity and moderate to warm temperatures. Peak spore production and infection occurs around 65 °F, though the pathogen is active in temperatures between 40 and 85 °F (Goldberg, 2000). This means that Peronospora trifoliorum is primarily seen during cool, wet periods in the summer or warmer, dry periods in the spring and fall, and is usually found in the midwestern and southern United States (UW-Extension, 2006). Since Peronospora trifoliorum is an oomycete, free moisture is needed for the disease to spread as well as to infect tissue (Goldberg, 2000). The disease may overwinter in dead leaf debris, in crown buds, or in seeds (UW-Extension, 2006: Pacific Northwest Extension, 2019).
Management
Growing resistant varieties of alfalfa is the most common form of control used against Peronospora trifoliorum (Samac, Rhodes, and Lamp, 2015). A form of cultural control, resistant varieties limit the ability of the disease to infect and survive in the plant. Another cultural control is to cut the alfalfa crop early, which removes the infectious conidia (Samac, Rhodes, and Lamp, 2015) while limiting the amount of foliage lost, removing the infected tissue, and decreasing the moisture and humidity through increased air circulation (Pacific Northwest Extension, 2019). While cultural controls are believed to be the most effective form of control against Peronospora trifoliorum, the use of chemical control in the form of metalaxyl and mefenoxam is common and effective for alfalfa seedlings (Samac, Rhodes, and Lamp, 2015). These systemic fungicides are used to suppress the infectious stage of the disease. Additionally, there have been attempts to find alternative methods to control Peronospora trifoliorum: a 2011 study used various biotic and abiotic compounds to test the use of bio- and chemical controls on different alfalfa diseases. The study found that to some degree, salicylic acid, potassium phosphite, neem oil, Bio-Arec, and Bio-Zaid betaine all protect against downy mildew and numerous other alfalfa diseases (Mohamed Morsy, Fawzy Abdel-Monaim, and Mamoud Mazen, 2011).
References
Peronosporales
Protists described in 1863
Water mould plant pathogens and diseases
Pulse crop diseases
Medicago
Plant pathogens and diseases
Oomycete species | Peronospora trifoliorum | [
"Biology"
] | 785 | [
"Plant pathogens and diseases",
"Plants"
] |
11,128,173 | https://en.wikipedia.org/wiki/Phaeosphaeria%20nodorum | Phaeosphaeria nodorum (syn. Stagonospora nodorum, synonym and correct taxonomic name: Parastagonospora nodorum) is a major fungal pathogen of wheat (Triticum aestivum), causing the disease Septoria nodorum blotch. It is a member of the Dothideomycetes, a large fungal taxon that includes many important plant pathogens affecting all major crop plant families.
Disease cycle
The infection occurs in repeated cycles of both asexual and sexual infection throughout the growing season. New rounds of infection are initiated by rain-splash or wind dispersal of spores. Infection begins when spores land on leaf tissue. The spores rapidly germinate to produce long, branching threadlike structures, called hyphae. The hyphae invade the leaf, using specialised branches to gain entry to the outermost layer of cells on the leaves. They can also grow directly through pores in the leaves. The hyphae rapidly colonize the leaves and begin to produce asexual fruiting bodies.
Management
Seed treatment
Seed treatment with fungicide - already used for bunts and smuts - has been discovered to eliminate seed transmission in wheat.
Model organism
Parastagonospora nodorum is an experimentally tractable organism, which is easily handled in defined media. It was one of the first fungal pathogens to be genetically manipulated. Parastagonospora nodorum has been a model for fungicide development and emerged as a model for dothideomycete pathology.
Genetics and genomics
Genomic resources
Parastagonospora nodorum has been sequenced and annotated by the Broad Institute.
Genetics
Genes for signal transduction factors are vital to the infection process. Functional genomics investigations by the Solomon group have dissected the roles of several, by disabling them and observing how they fail. In Solomon et al., 2005 & Solomon et al., 2006 they demonstrate how sporulation, pathogenicity, and stress tolerance are centrally related to several kinases, (a MAP kinase) and , , and (calmodulin kinases).
Taxonomy
In 2013, Quaedvlieg et al. introduced a new combination for this species: Parastagonospora nodorum (Berk.) Quaedvlieg, Verkley & Crous.
In the article named "Sizing up Septoria" they showed that the type of the fungal genus Stagonospora (Stagonospora paludosa) actually clustered inside the Massarinaceae and not in the Phaeosphaeriaceae as was previously assumed. They also showed that the type of the genus Phaeosphaeria (P. oryzae) does not cluster near Stagonospora nodorum. This means that both the Phaeosphaeria and Stagonospora names for this species are wrong. This caused that the Phaeosphaeriaceae located genus previously known as Stagonospora, incorporating several important pathogens on grasses (e.g. Stagonospora nodorum and S. avenae), was subsequently renamed into Parastagonospora with Parastagonospora nodorum being the type of this genus.
References
External links
Sizing up Septoria (Studies in Mycology 75: 307–390).
Phaeosphaeriaceae
Wheat diseases
Fungal plant pathogens and diseases
Fungi described in 1845
Taxa named by Miles Joseph Berkeley
Fungus species | Phaeosphaeria nodorum | [
"Biology"
] | 717 | [
"Fungi",
"Fungus species"
] |
11,128,183 | https://en.wikipedia.org/wiki/Phakopsora%20gossypii | Phakopsora gossypii is a plant pathogen and causal agent of cotton rust.
References
Fungal plant pathogens and diseases
Cotton diseases
Pucciniales
Fungus species | Phakopsora gossypii | [
"Biology"
] | 36 | [
"Fungi",
"Fungus species"
] |
11,128,190 | https://en.wikipedia.org/wiki/Cadophora%20malorum | Cadophora malorum is a saprophytic plant pathogen that causes side rot in apple and pear and can also cause disease on asparagus and kiwifruit. C. malorum has been found parasitizing shrimp and other fungal species in the extreme environments of the Mid-Atlantic Ridge, and can be categorized as a halophilic psychrotrophic fungus and a marine fungus.
Taxonomy
Cadophora malorum was first described as Sporotrichum malorum in 1924 by Mary Nest Kidd and Albert Beaumont, from a specimen collected on an apple tree in Britain, but in 2000 was transferred to the genus, Cadophora, by Walter Gams, a German mycologist. Extensive gene analysis has been done confirming the work of Walter Gams and categorizing C. malorum in the genus of Cadophora and distinguishing it from the previously named genus Phialophora.
Description
C. malorum is classified as a part of the Ascomycota division, because of the presence of asci and ascospores in its sexual reproductive lifecycle. C. malorum also shares typical morphological qualities with the Leotiomycetes class, Helotiales order, and the Ploettnerulaceae family. The Capophora genus has also been shown to be classified as ectomycorrhizal fungi (ECM fungi) and as dark septate endophytes (DSE).
Pathogenicity
C. malorum has been observed to infect pears during the post-harvest stage. C. malorum does not however infect pears until after some decay has already occurred. The source of inoculum for C. malorum has been shown to be in the soil, where the spores can overwinter and survive all year round off of nutrients released into the soil from decaying fruit. C. malorum can infect wounded bark and cause cankers to form in the trunk of the infected tree. C. malorum also can cause dieback in the leaves and fruit through wilting, yellowing, and necrosis of the plant. This has been known to happen on sunflower plants and kiwi trees.
Research has been conducted with isolation of C. malorum from shrimp and other fungal species, but research was not specific about how C. malorum infects organisms outside of the plantae kingdom. There is a lot of potential for further research in this area as it is rare for fungal species to be able to infect both plants and animals.
Geographical Distribution
C. malorum has been documented to be found parasitizing organisms all over the globe, showing up in research done in Slovenia, Russia, Chile, United States, Germany, Italy, along with various other countries. C. malorum has also been found in moderate to extreme environments such as the Mid-Atlantic Ridge and Antarctica.
Future research potential
Marine-derived fungi, like C. malorum, have been used to research biotechnological advances for a long time. Fungi have been used to create many modern products that are still used today, such as: dyes, flavors, fragrances, hallucinogens, poisons, and pesticides.
Medical
Marine fungi produce valuable secondary metabolites that can lead to innovations in potential drug-therapies. The secondary metabolites in C. malorum give an advantage for its own pathogenicity, but can also be used in developing beneficial pharmaceuticals, different food additives, and types of perfumes.
Biotechnological
C. malorum was discovered to possess these secondary metabolites along with genes encoding for carbohydrate-active enzymes, signifying that these genes have been adapted to extreme environments and thus have high biotechnological potential. C. malorum secondary metabolites can be used to develop various pesticides such as insecticides. Using living organisms as a pest control mechanism has been proven to be a useful, environmentally conscious, and sustainable method rather than the typical chemicals used.
References
Fungal fruit diseases
Fungi described in 2000
Helotiales
Fungus species | Cadophora malorum | [
"Biology"
] | 835 | [
"Fungi",
"Fungus species"
] |
11,128,197 | https://en.wikipedia.org/wiki/Phoma%20glomerata | Phoma glomerata is a fungus pathogen with several hosts. It mainly spoils wool because it badly alters the fibers.
See also
List of mango diseases
List of hemp diseases
List of elm diseases
List of wheat diseases
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Fungal tree pathogens and diseases
Mango tree diseases
Wheat diseases
glomerata
Fungi described in 1936
Fungus species | Phoma glomerata | [
"Biology"
] | 87 | [
"Fungi",
"Fungus species"
] |
11,128,198 | https://en.wikipedia.org/wiki/Nearly%20neutral%20theory%20of%20molecular%20evolution | The nearly neutral theory of molecular evolution is a modification of the neutral theory of molecular evolution that accounts for the fact that not all mutations are either so deleterious such that they can be ignored, or else neutral. Slightly deleterious mutations are reliably purged only when their selection coefficient are greater than one divided by the effective population size. In larger populations, a higher proportion of mutations exceed this threshold for which genetic drift cannot overpower selection, leading to fewer fixation events and so slower molecular evolution.
The nearly neutral theory was proposed by Tomoko Ohta in 1973. The population-size-dependent threshold for purging mutations has been called the "drift barrier" by Michael Lynch, and used to explain differences in genomic architecture among species.
Origins
According to the neutral theory of molecular evolution, the rate at which molecular changes accumulate between species should be equal to the rate of neutral mutations and hence relatively constant across species. However, this is a per-generation rate. Since larger organisms have longer generation times, the neutral theory predicts that their rate of molecular evolution should be slower. However, molecular evolutionists found that rates of protein evolution were fairly independent of generation time.
Noting that population size is generally inversely proportional to generation time, Tomoko Ohta proposed that if most amino acid substitutions are slightly deleterious, this would increase the rate of effectively neutral mutation rate in small populations, which could offset the effect of long generation times. However, because noncoding DNA substitutions tend to be more neutral, independent of population size, their rate of evolution is correctly predicted to depend on population size / generation time, unlike the rate of non-synonymous changes.
In this case, the faster rate of neutral evolution in proteins expected in small populations (due to a more lenient threshold for purging deleterious mutations) is offset by longer generation times (and vice versa), but in large populations with short generation times, noncoding DNA evolves faster while protein evolution is retarded by selection (which is more significant than drift for large populations) In 1973, Ohta published a short letter in Nature suggesting that a wide variety of molecular evidence supported the theory that most mutation events at the molecular level are slightly deleterious rather than strictly neutral.
Between then and the early 1990s, many studies of molecular evolution used a "shift model" in which the negative effect on the fitness of a population due to deleterious mutations shifts back to an original value when a mutation reaches fixation. In the early 1990s, Ohta developed a "fixed model" that included both beneficial and deleterious mutations, so that no artificial "shift" of overall population fitness was necessary. According to Ohta, however, the nearly neutral theory largely fell out of favor in the late 1980s, because the mathematically simpler neutral theory for the widespread molecular systematics research that flourished after the advent of rapid DNA sequencing. As more detailed systematics studies started to compare the evolution of genome regions subject to strong selection versus weaker selection in the 1990s, the nearly neutral theory and the interaction between selection and drift have once again become an important focus of research.
Theory
The rate of substitution, is
,
where is the mutation rate, is the generation time, and is the effective population size. The last term is the probability that a new mutation will become fixed. Early models assumed that is constant between species, and that increases with . Kimura’s equation for the probability of fixation in a haploid population gives:
,
where is the selection coefficient of a mutation. When (completely neutral), , and when (extremely deleterious), decreases almost exponentially with . Mutations with are called nearly neutral mutations. These mutations can fix in small- populations through genetic drift. In large- populations, these mutations are purged by selection. If nearly neutral mutations are common, then the proportion for which is dependent on
The effect of nearly neutral mutations can depend on fluctuations in . Early work used a “shift model” in which can vary between generations but the mean fitness of the population is reset to zero after fixation. This basically assumes the distribution of is constant (in this sense, the argument in the previous paragraphs can be regarded as based on the “shift model”). This assumption can lead to indefinite improvement or deterioration of protein function. Alternatively, the later “fixed model” fixes the distribution of mutations’ effect on protein function, but allows the mean fitness of population to evolve. This allows the distribution of to change with the mean fitness of population.
The “fixed model” provides a slightly different explanation for the rate of protein evolution. In large populations, advantageous mutations are quickly picked up by selection, increasing the mean fitness of the population. In response, the mutation rate of nearly neutral mutations is reduced because these mutations are restricted to the tail of the distribution of selection coefficients.
The “fixed model” expands the nearly neutral theory. Tachida classified evolution under the “fixed model” based on the product of and the variance in the distribution of : a large product corresponds to adaptive evolution, an intermediate product corresponds to nearly neutral evolution, and a small product corresponds to almost neutral evolution. According to this classification, slightly advantageous mutations can contribute to nearly neutral evolution.
The "drift barrier" theory
Michael Lynch has proposed that variation in the ability to purge slightly deleterious mutations (i.e. variation in ) can explain variation in genomic architecture among species, e.g. the size of the genome, or the mutation rate. Specifically, larger populations will have lower mutation rates, more streamlined genomic architectures, and generally more finely tuned adaptations. However, if robustness to the consequences of each possible error in processes such as transcription and translation substantially reduces the cost of making such errors, larger populations might evolve lower rates of global proofreading, and hence have higher rates of error. This may explain why Escherichia coli has higher rates of transcription error than Saccharomyces cerevisiae. This is supported by the fact that transcriptional error rates in E. coli depend on protein abundance (which is responsible for modulating the locus-specific strength of selection), but do so only for high-error-rate C to U deamination errors in S. cerevisiae.
See also
History of molecular evolution
References
External links
The Nearly Neutral Theory of Molecular Evolution - Perspectives on Molecular Evolution
Molecular evolution
Population genetics
Neutral theory | Nearly neutral theory of molecular evolution | [
"Chemistry",
"Biology"
] | 1,306 | [
"Evolutionary processes",
"Molecular evolution",
"Neutral theory",
"Molecular biology",
"Non-Darwinian evolution",
"Biology theories"
] |
11,128,203 | https://en.wikipedia.org/wiki/Phoma%20costaricensis | Phoma costaricensis is a plant pathogen infecting coffee. It is a soil fungus that infects the leaves and fruits of the coffee plant prior to the fruit ripening.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Coffee diseases
costaricensis
Fungi described in 1957
Fungus species | Phoma costaricensis | [
"Biology"
] | 69 | [
"Fungi",
"Fungus species"
] |
11,128,217 | https://en.wikipedia.org/wiki/Phoma%20insidiosa | Phoma insidiosa is a plant pathogen infecting wheat.
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Wheat diseases
insidiosa
Fungi described in 1884
Fungus species | Phoma insidiosa | [
"Biology"
] | 45 | [
"Fungi",
"Fungus species"
] |
11,128,225 | https://en.wikipedia.org/wiki/Leptosphaeria%20sacchari | Leptosphaeria sacchari (teleomorph—Phyllosticta sp) is a plant pathogenic fungus which causes a disease called ring spot on Saccharum officinarum. This species was originally described in 1890 by Kruger and in 1892 by Van Breda de Haan after it was discovered in the Dominican Republic. L. sacchari is the applied name, whereas Epicoccum sorghinum is the accepted name.
Disease symptoms and control
Hosts and symptoms
Leptosphaeria sacchari is an ascomycete fungus whose only known host is sugarcane. The infection occurs on the leaves of lower canopy of the crop and starts out as small bronze spots. The spots elongate to become longer, irregular-shaped lesions (2.5 to 5 mm x 10 to 18 mm) with red-brown borders. The spots can merge and cause leaf chlorosis and later necrosis. In older lesions, L. sacchari can form small, black dots, but usually only on older leaves. These black dots can be identified as perithecia and pynidia.
Prevention methods
Due to its effect on older parts of the crop, ring spot is considered to be a minor disease with no economic importance. Therefore, prevention and control methods are not well established for L. sacchari and are instead aimed at more influential diseases such as brown rust (Puccinia melanocephala), orange rust (Puccinia kuehnii), smut (Sporisorium scitamineum) and others. One control method includes examining genotypes of sugarcane in order to select for more resistant species to prevent ring spot in future generations of the crop. Those which show high susceptibility to ring spot and other diseases are discarded. Calcium silicate slag, a soil amendment, has been shown to drastically impact sugarcane yield as well as lessen any impact ring spot may have on the crop.
Microscopic characteristics and dispersal methods
Leptosphaeria sacchari produces globose to subglobose ascomata which can be up to 200 μm in size. Asci have an oblong-cylindric shape and are 40-60 X 8-12 μm. The ascospores are yellow to light brown in color and 18-23 X 3-5.5 μm and have a fusiform shape. Ring spot disease is spread through spores that are wind and rain-dispersed. This fungus has a preference for humid, tropical environments and can appear in sugarcane which has been planted in sandy or stony soils with low fertility. A hurricane in September 1928 was apparently responsible for bringing it to Florida from Puerto Rico.
Importance
Although ring spot is currently only a minor disease with little to no known impact on crop yield, with the changing climate, worsening of plant diseases may occur in the near future. Some reports show that on occasion L. sacchari can cause leaf blight in sugarcane seedlings, which can cause water stress and other symptoms which are more likely to affect yield. In general, climate change is capable of turning any minor disease into a major one and can greatly affect communities which rely on particular crops for consumption or income purposes. In 1926, ring spot caused growth retardation on the island of Oahu and was responsible for serious outbreaks in susceptible varieties in multiple other tropical regions. Therefore, there is a need to study L. sacchari and other seemingly minor plant pathogens before they become dangerous and have larger and more devastating effects on environmental and human ecology.
Geographical distribution
This fungal plant pathogen has been found in multiple continents including North America, Africa and Asia. L. sacchari has been cited in The United States (Florida), Cuba, Puerto Rico, Mexico, Dominican Republic, American Samoa, Sudan, Iraq, Thailand, India and multiple cities in China (Anhui, Guangdong, Fujian, Guangxi, Jiangxi).
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Pleosporales
Fungus species
Fungi described in 1892 | Leptosphaeria sacchari | [
"Biology"
] | 834 | [
"Fungi",
"Fungus species"
] |
11,128,231 | https://en.wikipedia.org/wiki/Phomopsis%20coffeae | Phomopsis coffeae is a plant pathogen infecting coffee.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Coffee diseases
coffeae
Fungus species
Fungi described in 1936 | Phomopsis coffeae | [
"Biology"
] | 42 | [
"Fungi",
"Fungus species"
] |
11,128,235 | https://en.wikipedia.org/wiki/Phomopsis%20prunorum | Phomopsis prunorum is a plant pathogen infecting apples.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Apple tree diseases
prunorum
Fungus species | Phomopsis prunorum | [
"Biology"
] | 39 | [
"Fungi",
"Fungus species"
] |
11,128,237 | https://en.wikipedia.org/wiki/Phomopsis%20tanakae | Phomopsis tanakae is a fungal plant pathogen infecting apples.
References
External links
USDA ARS Fungal Database
Fungal tree pathogens and diseases
Apple tree diseases
tanakae
Fungus species | Phomopsis tanakae | [
"Biology"
] | 38 | [
"Fungi",
"Fungus species"
] |
11,128,241 | https://en.wikipedia.org/wiki/Phragmidium%20violaceum | Phragmidium violaceum is a plant pathogen native to Europe, Africa, and the Middle East. It primarily infects Rubus species.
It has been used in the biological control of invasive blackberry species in Chile, Australia, and New Zealand. In 2005, it was discovered growing on Himalayan blackberry plants in Oregon. This accidental introduction does not appear to be infecting native vegetation, so it offers hope for reducing the impact of invasive blackberries in the Pacific Northwest.
Symptoms
The foliar symptoms that can be found include purple leaf spots along with yellow and tan centers. These can be found on the upper surface of the leaf and can resemble Septoria leaf spot. On the lower surface of the leaf yellow to orange pustules will be surrounded by a purple tinge. These can resemble cane and leaf rust. The leaves that are severely infected can start to dehydrate as well as start to curl. The leaves that are older and closer to the cane will get infected first and can die as well. The flowers and the fruits that are infected may fail to ripen. Stem infections as well as the continuous defoliation may cause the dieback of the canes. During the summer and fall the infected leaves can start to develop black pustules otherwise known as telia among the uredinia.
Disease cycle
The pathogen is a macrocyclic, autoecious rust fungus, and produces five different spore states that represent the asexual and sexual components of the life cycle. Dikaryotic urediniospores are released during the summer as well as the spring while teliospores represent the overwintering stage. When the sexual outcrossing occurs the dikaryotic aeciospores and urediniospores are initiated. The teliospores in the spring will then undergo meiosis in order to produce haploid basidiospores. This follows the insect-mediated transfer of spermatia from the spermogonia of the different types of mating to the receptive hyphae. The spores are spread very easily and can be spread by wind.
Management
Cultural tactics along with dormant season lime sulfur can help to reduce the initial inoculums source. The chemical tactics function to protect the healthy younger plant tissues. By removing the old fruiting canes early, after the harvest it will prevent the spreading of the infection. Chemical controls can be effective as well. Chemical protection will need to start by applying lime sulfur to the leaves that are infected. Fungicide application during fall, in the month of September, is the most beneficial for the health of the plant. There may be development of fungal resistance if there is overuse of any single product. The fungicides are primarily protectants therefore, cannot eradicate the disease after it becomes established. The biological control works when an uncharacterized population and or a mixture of strains of a pathogen from the native range of the target weed is released in the area into which the weed is introduced. The strain F15 was released as a biological control agent in 1991 and 1992. The release of the additional strains can originate the potential to increase the genetic diversity of the population of P. violaceum. The occurrence through recombination or the increase in the effective population size can in turn improve the impact of the biological control agent. Biological control agent is likely to be successful, however there is a high potential for the failure of additional strains due to the amount of inoculums involved in the pathogen strain recruitment. The amount of inoculums released is small when compared with the well-adapted pathogen that exists in the population
References
External links
Oregon Department of Agriculture
Fungal plant pathogens and diseases
Small fruit diseases
Pucciniales
Fungi of Africa
Fungi of Asia
Fungi of Europe
Fungi described in 1806
Fungus species | Phragmidium violaceum | [
"Biology"
] | 779 | [
"Fungi",
"Fungus species"
] |
11,128,256 | https://en.wikipedia.org/wiki/Phyllosticta%20carpogena | Phyllosticta carpogena is a fungal plant pathogen infecting caneberries.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Small fruit diseases
carpogena
Fungus species | Phyllosticta carpogena | [
"Biology"
] | 43 | [
"Fungi",
"Fungus species"
] |
11,128,261 | https://en.wikipedia.org/wiki/Phyllosticta%20coffeicola | Phyllosticta coffeicola is a fungal plant pathogen infecting coffee.
References
External links
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Coffee diseases
coffeicola
Fungi described in 1896
Fungus species | Phyllosticta coffeicola | [
"Biology"
] | 47 | [
"Fungi",
"Fungus species"
] |
11,128,270 | https://en.wikipedia.org/wiki/Phyllosticta%20solitaria | Phyllosticta solitaria is a fungal plant pathogen infecting apples.
References
External links
USDA ARS Fungal Database
Fungal tree pathogens and diseases
Apple tree diseases
solitaria
Fungi described in 1895
Taxa named by Benjamin Matlack Everhart
Fungus species | Phyllosticta solitaria | [
"Biology"
] | 55 | [
"Fungi",
"Fungus species"
] |
11,128,289 | https://en.wikipedia.org/wiki/Physoderma%20alfalfae | Physoderma alfalfae is a species of fungus in the family Physodermataceae. A plant pathogen, it causes crown wart of alfalfa.
References
Fungal plant pathogens and diseases
Fungi described in 1895
Blastocladiomycota
Fungus species | Physoderma alfalfae | [
"Biology"
] | 57 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
11,128,317 | https://en.wikipedia.org/wiki/Plenodomus%20meliloti | Plenodomus meliloti is a plant pathogen infecting alfalfa and red clover.
References
Fungal plant pathogens and diseases
Pleosporales
Fungus species
Fungi described in 1930 | Plenodomus meliloti | [
"Biology"
] | 41 | [
"Fungi",
"Fungus species"
] |
11,128,321 | https://en.wikipedia.org/wiki/Pleospora%20alfalfae | Pleospora alfalfae is a plant pathogen infecting alfalfa.
References
Fungal plant pathogens and diseases
Pleosporaceae
Fungi described in 1986
Fungus species | Pleospora alfalfae | [
"Biology"
] | 38 | [
"Fungi",
"Fungus species"
] |
11,128,326 | https://en.wikipedia.org/wiki/Pleospora%20herbarum | Pleospora herbarum is a species of fungus in the family Pleosporaceae. It is a plant pathogen infecting several hosts including alfalfa, apples, asparagus, tomatoes, citruses and chickpea. It has a cosmopolitan distribution, and is common in temperate and subtropical regions. The fungus was first described under the name Sphaeria herbarum by Christian Hendrik Persoon in 1801.
References
Fungal plant pathogens and diseases
Apple tree diseases
Vegetable diseases
Tomato diseases
Fungal citrus diseases
Fungi of Africa
Fungi of Australia
Fungi of Asia
Fungi of Europe
Fungi of Central America
Fungi of North America
Fungi of South America
Pleosporaceae
Fungi described in 1801
Taxa named by Christiaan Hendrik Persoon
Fungus species | Pleospora herbarum | [
"Biology"
] | 154 | [
"Fungi",
"Fungus species"
] |
11,128,334 | https://en.wikipedia.org/wiki/Stemphylium%20botryosum | Stemphylium botryosum (family Pleosporaceae, order Pleosporales) is a species of fungi and plant pathogen infecting several hosts including alfalfa, red clover, peanut, soybean, lentils, beet, tomato, lettuce, hemp and carnations.
It was originally found on Medicago sativa (Alfalfa) in Ontario, Canada and named as Pleospora tarda but it was later found to be the anamorph of Stemphylium botryosum .
See also
List of soybean diseases
References
External links
Index Fungorum
USDA ARS Fungal Database
Fungal plant pathogens and diseases
Pulse crop diseases
Tomato diseases
Lettuce diseases
Hemp diseases
Ornamental plant pathogens and diseases
Pleosporaceae
Soybean diseases
Fungi described in 1833
Fungus species | Stemphylium botryosum | [
"Biology"
] | 178 | [
"Fungi",
"Fungus species"
] |
11,128,341 | https://en.wikipedia.org/wiki/Podosphaera%20leucotricha | Podosphaera leucotricha is a plant pathogen that can cause powdery mildew of apples and pears.
Importance
A net-like russeting can cut the value of fruit in half and with some orchards spraying up to 15 times per growing season the economic losses from P. leucotricha are high.
Hosts and symptoms
Powdery mildew, caused by the obligate biotrophic ascomycete Podosphaera leucotricha, is one of the major diseases of cultivated apple throughout the world. The primary host is apple, but other fruit like peaches and quince provide a host for Podosphaera leucotricha. A list of host plants/species affected includes Cydonia oblonga (quince), Malus (apple), Prunus persica (peach), Prunus domestica (plum), Pyrus (pears), and Mespilus germanica (medlar). On apples, the fungus affects twigs, foliage, blossoms, and fruits of current season growth. Infected plants are characterized by reduced photosynthesis and transpiration, resulting suboptimal carbohydrate assimilation and reduced growth.
Podosphaera leucotricha causes a range of symptoms. On stems, symptoms include wilting and discoloration. Wilting and leaf curling occur on leaves. Symptoms of the inflorescence include discoloration (non-graminous plants), dwarfing, stunting, and twisting. On fruit symptoms include net-like russeting and deformed fruit. Depending on the stage in the disease cycle, symptoms vary. The primary blossom mildew emerges at pink bud stage. Flowers are deformed with pale green or yellow petal and are covered in white mycelium and spores. The secondary mildew may have lesions that appear as chlorotic spots on the upper leaf surface. Symptoms of the secondary mildew also included distorted leaves and premature falling of leaves.
Disease cycle
Podosphaera leucotricha has a polycyclic disease cycle. Mycelium overwintering in dormant buds typically produces primary infection on young leaves, which produce inoculum in the form of conidia for the secondary cycles. In spring, the overwintered fungus is evident as 'primary' mildew on leaves emerged from buds infected during the previous growing season. Conidia that are (12 X 20-38 um) and are ellipsoidal, truncate and hyaline are released from the primary mildew during the colonies disperse in air and initiate an epidemic of 'secondary' mildew on growing shoots. Young developing fruitlets may also be infected. Secondary mildew epidemics are effectively continuous from day to day. The infection process does not require surface wetness. Daily infection intensity on leaves is mainly determined by the dose of landed conidia, which is dependent on the concentration of airborne conidia and wind speed. Apple shoots have a long growing season causing the tree to stay susceptible for several months. The pathogen is supposed to spread almost exclusively asexually, although ascospores might be an underrated additional source of infection. Occasionally the sexual state of P. leucotricha occurs as pin-head sized brown/black fruiting bodies (ascocarps) among mycelium on infected shoots or leaves. Although the mycelium can overwinter in dormant buds, overwintering potential is limited primarily by temperature. In severe winters, infected buds are killed as they are more susceptible to the cold than healthy buds.
Management
Intensive applications of fungicides are usually used to control apple powdery mildew. In the UK, most commercial apple orchards receive routine sprays. This is because mildew is always present in the orchard and therefore routine chemical control measures are usually needed. Spraying occurs from green cluster until vegetative growth ceases, and occasionally post-harvest if terminal buds regrow. Once primary mildew levels are high, effective control becomes difficult. Therefore, control strategies depend on maintaining primary mildew at a low level. When levels are high, prompt physical removal of blossoms or shoots may be the only effective way to reduce inoculum levels. In organic orchards, control is based on a combination of cultural levels and fungicide use where possible, but sulphur is the only fungicide active against powdery mildew permitted for use in organic production. Cultural levels are based on removal of primary inoculum by pruning. In winter, prune out silvered shoots. At pink bud and petal fall stages, prune out primary blossom and primary blossom and primary vegetative mildew. There are times when controlling mildew is most important. June is a critical time for monitoring and mildew control as this is the period for rapid extension growth and also when fruit buds are forming and sealing for next spring. Fungicides and cultural controls are the main ways to manage P. leucotricha, however the development of apple varieties displaying durable resistance to the fungi is one of the major aims of apple breeding programs worldwide.
References
External links
Keepers Nursery - Apple and Pear Powdery Mildew
Fungal plant pathogens and diseases
Apple tree diseases
Pear tree diseases
leucotricha
Fungi described in 1887
Fungus species | Podosphaera leucotricha | [
"Biology"
] | 1,086 | [
"Fungi",
"Fungus species"
] |
11,128,348 | https://en.wikipedia.org/wiki/Podosphaera%20tridactyla%20var.%20tridactyla | Podosphaera tridactyla var. tridactyla is a plant pathogen infecting almond.
References
Fungal tree pathogens and diseases
Fruit tree diseases
tridactyla var. tridactyla
Fungus species | Podosphaera tridactyla var. tridactyla | [
"Biology"
] | 47 | [
"Fungi",
"Fungus species"
] |
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