Rusts are fungal plant pathogens of the order Pucciniales causing plant fungal diseases.
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.
Apple scab is a common disease of plants in the rose family (Rosaceae) that is caused by the ascomycete fungus Venturia inaequalis. While this disease affects several plant genera, including Sorbus, Cotoneaster, and Pyrus, it is most commonly associated with the infection of Malus trees, including species of flowering crabapple, as well as cultivated apple. The first symptoms of this disease are found in the foliage, blossoms, and developing fruits of affected trees, which develop dark, irregularly-shaped lesions upon infection. Although apple scab rarely kills its host, infection typically leads to fruit deformation and premature leaf and fruit drop, which enhance the susceptibility of the host plant to abiotic stress and secondary infection. The reduction of fruit quality and yield may result in crop losses of up to 70%, posing a significant threat to the profitability of apple producers. To reduce scab-related yield losses, growers often combine preventive practices, including sanitation and resistance breeding, with reactive measures, such as targeted fungicide or biocontrol treatments, to prevent the incidence and spread of apple scab in their crops.
Hemileia vastatrix is a multicellular basidiomycete fungus of the order Pucciniales that causes coffee leaf rust (CLR), a disease affecting the coffee plant. Coffee serves as the obligate host of coffee rust, that is, the rust must have access to and come into physical contact with coffee in order to survive.
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.
Urediniospores are thin-walled spores produced by the uredium, a stage in the life-cycle of rusts.
Ug99 is a lineage of wheat stem rust, which is present in wheat fields in several countries in Africa and the Middle East and is predicted to spread rapidly through these regions and possibly further afield, potentially causing a wheat production disaster that would affect food security worldwide. In 2005 the noted green revolution pioneer Norman Borlaug brought great attention to the problem, and most subsequent efforts can be traced to his advocacy. It can cause up to 100% crop losses and is virulent against many resistance genes which have previously protected wheat against stem rust.
Glomerella graminicola is an economically important crop parasite affecting both wheat and maize where it causes the plant disease Anthracnose Leaf Blight.
Alternaria japonica is a fungal plant pathogen. It is a cause of black spot disease in cruciferous plants. It is not a major source of crop loss, but is considered dangerous for plants during the seedling stage.
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 horiana is a species of fungus that causes chrysanthemum white rust, is a disease of plant species of the genus Chrysanthemum.
Puccinia jaceae var. solstitialis is a species of fungus in the Pucciniaceae family. It is a plant pathogen that causes rust. Native to Eurasia, it is the first fungal pathogen approved in the United States as a biological control agent to curb the growth of the invasive weed yellow starthistle.
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.
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.
Puccinia sorghi, or common rust of maize, is a species of rust fungus that infects corn and species from the plant genus Oxalis.
Colletotrichum fioriniae is a fungal plant pathogen and endophyte of fruits and foliage of many broadleaved plants worldwide. It causes diseases on agriculturally important crops, including anthracnose of strawberry, ripe rot of grapes, bitter rot of apple, anthracnose of peach, and anthracnose of blueberry. Its ecological role in the natural environment is less well understood, other than it is a common leaf endophyte of many temperate trees and shrubs and in some cases may function as an entomopathogen.
Bitter rot of apple is a fungal disease of apple fruit that is caused by several species in the Colletotrichum acutatum and Colletotrichum gloeosporioides species complexes. It is identified by sunken circular lesions with conical intrusions into the apple flesh that appear V-shaped when the apple is cut in half through the center of the lesion. It is one of the most devastating diseases of apple fruit in regions with warm wet weather.
Thecaphora frezzii, commonly referred to as peanut smut, is a species of smut fungus of the genus Thecaphora and the family Glomosporiaceae. It is a basidiomycete fungus that infects peanut plants. It is currently only found in South America, more specifically in Argentinian peanut farms.
