| Puccinia helianthi | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Pucciniomycetes |
| Order: | Pucciniales |
| Family: | Pucciniaceae |
| Genus: | Puccinia |
| Species: | P. helianthi |
| Binomial name | |
| Puccinia helianthi Schwein. (1822) | |
Puccinia helianthi is a macrocyclic and autoecious fungal plant pathogen that causes rust on sunflower. [1] [2] It is also known as "common rust" and "red rust" of sunflower. [3]
P. helianthi is the main causal agent of sunflower rust, but four other Puccinia species can also cause rust on cultivated and wild sunflower species. Although they rarely appear, it can be difficult to distinguish them from P. helianthi on sunflower. Both P. enceliae and P. massalis produce uredia and telia that can only be differentiated from those produced by P. helianthi using teliospore morphology. P. xanthii, also known as cocklebur rust, is microcyclic and only forms telia. P. canaliculata, known as nutsedge rust, only produces uredia and telia on its alternate host, nutsedge. [4]
When environmental conditions are favorable for disease development, a substantial reduction in sunflower seed quality and yield can occur. These conditions include:
P. helianthi produces these symptoms on sunflower:
The most identifiable sign of P. helianthi is the uredinia which forms rust-colored pustules on leaves, stems, petioles, and bracts. These darken into black, telial resting pustules once temperatures decrease. Flask-shaped pycnia appear as yellow-orange spots, 6mm or less, on the upper side of leaves in early spring. Collections of similarly-sized aecia are visible as orange cups directly below on the underside of leaves. [5]
P. helianthi produces five distinct spore stages during its life cycle. The uredinial stage is the repeating stage consisting of uredinia as red-brown, cinnamon-colored pustules containing thousands of urediniospores. During fall, these pustules turn black and begin producing overwintering teliospores in the telial stage. In early spring, the teliospores germinate to produce basidiospores, which disperse to infect sunflower seedlings. These infections elicit the pycnial and aecial spore stages, where flask-shaped pycnia is found embedded in the upper surfaces of leaf tissues, and aecia is seen directly below the pycnia on the dorsal side of leaves. Aeciospores that develop in the aecia reinfect sunflowers and reset the cycle by creating new uredinia. [2]
Cultural control recommendations for P. helianthi include:
Genetic control consists of planting rust-resistant hybrid varieties. [8]
Chemical management can be applied using fungicides on both oilseed and confection type sunflowers and is most effective during the (R5) flowering stage or when the disease severity reaches 1% on the upper four, fully expanded leaves. [9] [10]
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 coronata is a plant pathogen and causal agent of oat and barley crown rust. The pathogen occurs worldwide, infecting both wild and cultivated oats. Crown rust poses a threat to barley production, because the first infections in barley occur early in the season from local inoculum. Crown rusts have evolved many different physiological races within different species in response to host resistance. Each pathogenic race can attack a specific line of plants within the species typical host. For example, there are over 290 races of P. coronata. Crops with resistant phenotypes are often released, but within a few years virulent races have arisen and P. coronata can infect them.
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.
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.
Gymnosporangium sabinae is a species of rust fungus in the subdivision Pucciniomycotina. Known as pear rust, European pear rust, or pear trellis rust, it is a heteroecious plant pathogen with Juniperus sabina as the main primary (telial) host and Pyrus communis as the main secondary (aecial) host.
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 monoica is a parasitic rust fungus of the genus Puccinia that inhibits flowering in its host plant and radically transforms host morphology in order to facilitate its own sexual reproduction.
Puccinia horiana is a species of fungus that causes chrysanthemum white rust, is a disease of plant species of the genus Chrysanthemum.
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.
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 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.