| Puccinia sorghi | |
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Pucciniomycetes |
| Order: | Pucciniales |
| Family: | Pucciniaceae |
| Genus: | Puccinia |
| Species: | P. sorghi |
| Binomial name | |
| Puccinia sorghi | |
| Synonyms | |
Puccinia sorghi, or common rust of maize, is a species of rust fungus that infects corn and species from the plant genus Oxalis .
Puccinia sorghi often first appears after silking in maize. The first early symptom includes chlorotic specks on the leaf. The obvious sign of this plant pathogen is golden-brown pustules or bumps on the above-ground surface of the plant tissue. [5] These bumps are urediniospores which can spread to other plants and cause further infection. They are circular and powdery, which result from spores breaking through the leaf surface. While they are only about 1–2 mm each, they are very numerous with equal frequencies on upper and lower leaf surfaces. Over time, these blister-like bumps can change from brown to black, changing from urediniospores to teliospores. [6] The most common place to find these spores is on the plant leaf, but they can develop on husks, tassels, and stalks as well. P. sorghi has two hosts making it a heteroecious rust. Maize and Oxalis are the two hosts for P. sorghi. In comparison, the other common type of maize rust is southern corn rust ( Puccinia polysora ) and it has a higher variety of hosts including maize, silver plumegrass, eastern gamagrass , Tripsacum lanceolatum , T. laxum , and T. pilorum . [6]
There are five spore stages in P. sorghi. The spore types are teliospores, basidiospores, pycniospores, aeciospores, and urediniospores. Every year, viable urediniospores must travel to the north from the warmer southern climate. Since P. sorghi is an obligate parasite, it requires living plant tissue in order to survive. Therefore, this disease cannot overwinter in northern US states. The severity of the disease depends largely on weather conditions and how many spores are carried north each season. [7] Urediniospores infect leaves and produce more spores to create a secondary inoculum and polycyclic disease cycle. Once the urediniospores mature on the plant tissue and turn black they become teliospores. Urediniospores measure 22-33 × 20-28 μm. Teliospores are two-celled and measure 27-53 μm. [8] Teliospores overwinter in the southern climate and germinate in the spring. Teliospores produce basidiospores which spread by wind to infect Oxalis. They infect Oxalis and produce sexual spores (pycniospores) and aeciospores. Aeciospores are windblown to maize and infect the plant.
The use of resistant maize hybrids is the best way to manage P. sorghi. There are two types of resistance that exist. [9] The first is partial resistance which results in fewer rust spots by reducing germination rate. This type of resistance makes P. sorghi less severe by slowing down development of number of urediniospores. The other type of resistance is qualitative. This type relies on a single gene which provides total resistance to the plant. Other management tactics include foliar application of fungicide and cultural control. [10] For fungicide application, plants should be monitored throughout the season, spraying when there are six or more pustules per leaf. Fungicide groups that can be used include mixed modes of action, DMI Triazoles (Group 3), and QoI Strobilurins (Group 11). [11] Cultural control can be more effective in areas where the spores can overwinter. Debris should be collected and destroyed by burning along with eradication of Oxalis in surrounding areas. In northern areas where the spores can't overwinter, early planting time can help avoid P. sorghi. Younger leaves are more susceptible to infection, by planting earlier the crop will be more mature and more resilient by the time the spores arrive.
Rusts are fungal plant pathogens of the order Pucciniales causing plant fungal diseases.
Stem rust, also known as cereal rust, black rust, red rust or red dust, is caused by the fungus Puccinia graminis, which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat, durum wheat, barley and triticale. These diseases have affected cereal farming throughout history. The annual recurrence of stem rust of wheat in North Indian plains was discovered by K.C. Mehta. Since the 1950s, wheat strains bred to be resistant to stem rust have become available. Fungicides effective against stem rust are available as well.
Wheat leaf rust is a fungal disease that affects wheat, barley, rye stems, leaves and grains. In temperate zones it is destructive on winter wheat because the pathogen overwinters. Infections can lead up to 20% yield loss. The pathogen is a Puccinia rust fungus. It is the most prevalent of all the wheat rust diseases, occurring in most wheat-growing regions. It causes serious epidemics in North America, Mexico and South America and is a devastating seasonal disease in India. P. triticina is heteroecious, requiring two distinct hosts.
Teliospore is the thick-walled resting spore of some fungi, from which the basidium arises.
Gymnosporangium juniperi-virginianae is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (Malus) and eastern red cedar coexist, cedar apple rust can be a destructive or disfiguring disease on both the apples and cedars. Apples, crabapples, and eastern red cedar are the most common hosts for this disease. Similar diseases can be found on quince and hawthorn and many species of juniper can substitute for the eastern red cedars.
Phragmidium violaceum is a plant pathogen native to Europe, Africa, and the Middle East. It primarily infects Rubus species.
Puccinia schedonnardii is a basidiomycete fungus that affects cotton. More commonly known as a “rust,” this pathogen typically affects cotton leaves, which can decrease the quality of the boll at time of harvest. As large percentages of cotton in the United States are resistant to various rust varieties, there is little economic importance to this disease. In places where rust is prevalent, however, growers could see up to a 50% reduction in yield due to rust infection.
Puccinia asparagi is the causative agent of asparagus rust. It is an autoecious fungus, meaning that all stages of its life cycle – pycniospores, aeciospores, and teliospores – all develop upon the same host plant . Rust diseases are among the most destructive plant diseases, known to cause famine following destruction of grains, vegetables, and legumes. Asparagus rust occurs wherever the plant is grown and attacks asparagus plants during and after the cutting season. Asparagus spears are usually harvested before extensive rust symptoms appear. Symptoms are first noticeable on the growing shoots in early summer as light green, oval lesions, followed by tan blister spots and black, protruding blisters later in the season. The lesions are symptoms of Puccinia asparagi during early spring, mid-summer and later summer to fall, respectively. Severe rust infections stunt or kill young asparagus shoots, causing foliage to fall prematurely, and reduce the ability of the plant to store food reserves. The Puccinia asparagi fungus accomplishes this by rust lowering the amounts of root storage metabolites. The infected plant has reduced plant vigor and yield, often leading to death in severe cases. Most rust diseases have several stages, some of which may occur on different hosts; however, in asparagus rust all the life stages occur on asparagus. Because of this, many observers mistake the different stages of the Puccinia asparagi life cycle as the presence of different diseases. The effects of Puccinia asparagi are present worldwide wherever asparagus is being grown. Asparagus rust is a serious threat to the asparagus industry.
Puccinia helianthi is a macrocyclic and autoecious fungal plant pathogen that causes rust on sunflower. It is also known as "common rust" and "red rust" of sunflower.
Puccinia menthae is a fungal plant pathogen that causes rust on mint plants. It was originally found on the leaves of Mentha aquatica.
Uromyces viciae-fabae var. viciae-fabae is a plant pathogen commonly known as faba-bean rust. The rust is distinguished by the typical rust-like marks on the stem and leaves, causing defoliation and loss of photosynthetic surface along with reduction in yield. The disease is fungal and is autoecious meaning it has one plant host. The rust of faba beans is macrocyclic, or contains 5 spores during its life cycle.
Melampsora lini is a species of fungus and plant pathogen found in Ireland and commonly known as flax rust.
Phakopsora pachyrhizi is a plant pathogen. It causes Asian soybean rust.
Puccinia horiana is a species of fungus that causes chrysanthemum white rust, is a disease of plant species of the genus Chrysanthemum.
Austropuccinia is a monotypic genus of rust native to South America with the only species Austropuccinia psidii, commonly known as myrtle rust, guava rust, or ʻōhiʻa rust. It affects plants in the family Myrtaceae. It is a member of the fungal complex called the guava rust group. The spores have a distinctive yellow to orange colour, occasionally encircled by a purple ring. They are found on lesions on new growth including shoots, leaves, buds and fruits. Leaves become twisted and may die. Infections in highly susceptible species may result in the death of the host plant.
Telium, plural telia, are structures produced by rust fungi as part of the reproductive cycle. They are typically yellow or orange drying to brown or black and are exclusively a mechanism for the release of teliospores which are released by wind or water to infect the alternate host in the rust life-cycle. The telial stage provides an overwintering strategy in the life cycle of a parasitic heteroecious fungus by producing teliospores; this occurs on cedar trees. A primary aecial stage is spent parasitizing a separate host plant which is a precursor in the life cycle of heteroecious fungi. Teliospores are released from the telia in the spring. The spores can spread many kilometers through the air, however most are spread near the host plant.
Phragmidium is a genus of rust fungus that typically infects plant species in the family Rosaceae. It is characterised by having stalked teliospores borne on telia each having a row of four or more cells. All species have a caeoma which is a diffuse aecidium lacking a peridium.
Puccinia libanotidis, common name moon carrot rust, is a species of rust that infects the moon carrot, Seseli libanotis. It is restricted to the same range as its host plant across Eurasia.
Phakopsora euvitis is a rust fungus that causes disease of grape leaves. This rust fungus has been seen in regions including: Eastern Asia, Southern Asia, Southwestern Brazil, the Americas, and northern Australia. It is widely distributed in eastern and southern Asia but was first discovered on grapevines in Darwin, Australia in 2001 and was identified as Asian grapevine leaf rust by July 2007.
Puccinia porri is a species of rust fungus that causes leek rust. It affects leek, garlic, onion, and chives, and usually appears as bright orange spots on infected plants.
| Authority control databases: National |
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