Rusts are fungal plant pathogens of the order Pucciniales causing plant fungal diseases.
Asparagus is a genus of flowering plants in the family Asparagaceae, subfamily Asparagoideae. It comprises up to 300 species. Most are evergreen long-lived perennial plants growing from the understory as lianas, bushes or climbing plants. The best-known species is the edible Asparagus officinalis, commonly referred to as just asparagus. Some other members of the genus, such as Asparagus densiflorus, are grown as ornamental plants.
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 first found in Beijing China in 2009 by an Italian scientist, and Ken Deng. 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.
Asparagus asparagoides, commonly known as bridal creeper, bridal-veil creeper, gnarboola, smilax or smilax asparagus, is a herbaceous climbing plant of the family Asparagaceae native to eastern and southern Africa. Sometimes grown as an ornamental plant, it has become a serious environmental weed in Australia and New Zealand.
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.
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 recondita is a fungus species and plant pathogen belonging to the order of Pucciniales and family Pucciniaceae.
Puccinia thaliae is the causal agent of canna rust, a fungal disease of Canna. Symptoms include yellow to tan spots on the plant's leaves and stems. Initial disease symptoms will result in scattered sori, eventually covering the entirety of the leaf with coalescing postulates. Both leaf surfaces, although more predominant on the underside (abaxial) of the leaf, will show yellow to brownish spore-producing these pustulate structures, and these are the signs of the disease. Spots on the upper leaf-surface coalesce and turn to brown-to-black as the disease progresses. Infection spots will become necrotic with time, with small holes developing in older leaves. These infected leaves eventually become dry and prematurely fall.
Puccinia horiana is a species of fungus that causes chrysanthemum white rust, is a disease of plant species of the genus Chrysanthemum.
Wheat yellow rust, also known as wheat stripe rust, is one of the three major wheat rust diseases, along with stem rust of wheat and leaf rust.
Austropuccinia psidii, commonly known as myrtle rust, guava rust, or ʻōhiʻa rust; is a rust native to South America that 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.
Ruth Florence Allen (1879–1963) was an American botanist and plant pathologist and the first woman to earn her Ph.D. in botany from the University of Wisconsin. Her doctorate research focused on the reproduction and cell biology of ferns, particularly the phenomenon of apogamy. Later in her career, Allen shifted her focus to plant pathology. Her major contribution to the field of mycology was furthering the understanding of rust fungi, a group of economically important plant pathogens. Allen completed many studies on Puccinia graminis, once considered a catastrophically damaging disease-causing agent in cereal crops before the discovery of current management measures.
Edwin Butterworth Mains (1890–1968) was an American mycologist. He was known for his taxonomic research on the rust fungi (Pucciniomycetes), the genus Cordyceps, and the earth tongues (Geoglossaceae).
Margaret Brown Newton was a Canadian plant pathologist and mycologist internationally renowned for her pioneering research in stem rust Puccinia graminis, particularly for its effect on the staple Canadian agricultural product wheat.
Puccinia myrsiphylli is a rust fungus in the genus Puccinia, family Pucciniaceae, and is native to South Africa. It has been tested, introduced, and targeted in Australia and New Zealand as an effective biocontrol agent for Asparagus asparagoides, also known as bridal creeper.
Diane G. O. Saunders is a British biologist and group leader at the John Innes Centre and an Honorary Professor in the School of Biological Sciences at the University of East Anglia. Her research investigates plant pathogens that pose a threat to agriculture. She was awarded the Rosalind Franklin Award by the Royal Society in 2022.
