Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales.
Soybean rust is a disease that affects soybeans and other legumes. It is caused by two types of fungi, Phakopsora pachyrhizi, commonly known as Asian soybean rust and Phakopsora meibomiae, commonly known as New World soybean rust. P. meibomiae is the weaker pathogen of the two and generally does not cause widespread problems. The disease has been reported across Asia, Australia, Africa, South America and the United States.
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 Prof. 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, which is exacerbated by dying leaves, which fertilize the fungus. 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 globosum is a fungal plant pathogen that causes cedar-hawthorn rust.
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. Quince and hawthorn are the most common host 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.
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.
Naohidemyces vaccinii is a plant pathogen that affects members of the Vaccinium and Tsuga genera, causing leaf rust on lingonberries, blueberries, and cranberries, and early needle cast on hemlocks. Naohidemyces vaccinii is found on the Vaccinium genus in Canada, the United States, the United Kingdom, Europe, Russia, China, Korea, and Japan, and on hemlock in AK, ID, WA in the United States, BC in Canada, and Japan.
Phakopsora pachyrhizi is a plant pathogen. It causes Asian soybean rust.
Gymnosporangium sabinae is a fungal heteroecious plant pathogen with Juniperus as the primary (telial) host and only Pyrus as secondary (aecial) hosts. It is one of many types of rust fungi affecting plants.
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.
Pine-pine gall rust, also known as western gall rust, is a fungal disease of pine trees. It is caused by Endocronartium harknessii, an autoecious, endocyclic, rust fungus that grows in the vascular cambium of the host. The disease is found on pine trees with two or three needles, such as ponderosa pine, jack pine and scots pine. It is very similar to pine-oak gall rust, but its second host is another Pinus species. The fungal infection results in gall formation on branches or trunks of infected hosts. Gall formation is typically not detrimental to old trees, but has been known to kill younger, less stable saplings. Galls can vary from small growths on branch extremities to grapefruit-sized galls on trunks.
Spruce broom rust or yellow witches' broom rust is a fungal plant disease caused by the basidiomycete fungus known as Chrysomyxa arctostaphyli. It occurs exclusively in North America, with the most concentrated outbreaks occurring in northern Arizona and southern Colorado on blue and Engelmann spruce, as well as in Alaska on black and white spruce. This disease alternates its life cycle between two hosts, with the spruce serving as the primary host and bearberry serving as the secondary or alternate host. The name for the disease comes from the distinctive “witches broom”, commonly yellow in color, which forms on the spruce after young needles have been infected. Management must be carried out through physical or mechanical methods, such as the pruning of brooms or the removal of the secondary host from the area, because no chemical control measures have yet been determined to be economically effective. Generally, spruce broom rust is seen as a mostly cosmetic issue, and it is very rarely the direct cause of tree death; however, research has shown a reduction in overall productivity and health of infected trees, making it an important issue for logging and timber companies.
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.
Melampsora amygdalinae is a fungal pathogen and part of the division Basidiomycota. It is known as a rust fungus that is host specific. M. amygdalinae commonly infects willows of the genus Salix. This fungus was first discovered in 1909 by Heinrich Klebahn who was a professor of soil biology in Hamburg. Neimi at el. explain how the pathogen occurs throughout the whole distribution of the host, and the small natural populations are an area of interest. This rust fungus is annual and autoecious, which references the fungus spending its entire life in a single host.
Puccinia sorghi, or common rust of maize, is a species of rust fungus that infects corn and species from the plant genus Oxalis.
