Puccinia thaliae | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Basidiomycota |
Class: | Pucciniomycetes |
Order: | Pucciniales |
Family: | Pucciniaceae |
Genus: | Puccinia |
Species: | P. thaliae |
Binomial name | |
Puccinia thaliae Dietel | |
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 (clustered sporangia), 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 (3 to 5mm) developing in older leaves. These infected leaves eventually become dry and prematurely fall. [1]
When canna rust first appears, the affected foliage should be removed and discarded, otherwise the fungi will propagate and destroy the whole plant. The affected foliage should not be composted, as that will simply spread the fungus further.
Because canna rust thrives in warm, moist conditions (~20 °C), it is best to reduce irrigation or implement methods to reduce standing water, such as mulch and planting in the sun.
Commercially, a liquid copper-based spray can be sprayed on the stems and both sides of the leaves to prevent fungal problems before they occur. Although used commercially, copper is not recommended for home use because of its heavy metal toxicity.
Other practices include, reducing plant material or debris and reducing foliage from the plant. This practice can increase the aeration of the canopy, permitting more light and allowing fungicide sprays (if used) to reach the plant. [2] This method disrupts the uredospores stage from persisting.
Puccinia thaliae is a systemic pathogen, in that symptoms will affect a greater part or all of the plant. [3]
The disease cycle for canna rust has not been fully discovered, but there are several known pieces. Urediniospores (or uredospores), asexual rust spores, have been discovered on the leaf surface. [4] The color of the urediniospore can range from a golden to a yellow-orange, and are egg or pear shaped. [4] The uredospores are responsible for the spread of the rust to new leaf tissue. Uredospores are subglobose to ovoid or pyriform, echinulate, and measure 25.74 to 37.18 x 17.16 to 27.17 μm, with thickened walls apical walls (1.3 to 1.6 μm) and one to two equatorial germ pores. In addition, the overwintering spores that produce basidiospores, also known as teliospores, have been located on the leaf surface. [4] The teliospores range from cylindrical, clavate to club shaped, with rounded apex and sized from 50−83 × 14−21 μm. [5] [4] Basidiospores are the sexual spores of rusts. There have been no pycnia or aecia located on Canna Rust. [4] However, P. thaliae has been known to cause rust on several cannabis species and on arrowroot which are other uredial hosts. [6] The pathogen is likely mobile in the plant leaf allowing it to spread across the leaf surface. The overwintering stage occurs during the wet and cold seasons.
The canna rust fungus grows best under high relative humidity and extended periods of leaf wetness (roughly ≥20 °C). This type of environment can be caused by high soil moisture, tall weeds surrounding the Canna, and dense shading that prevents moisture from evaporating from the leaf surface. [4] The fungus can survive in most tropical environments where the canna lily grows due to the tropics high relative moisture throughout the growing season. [4] P. thaliae has been reported throughout Europe and extends throughout the northern hemisphere. [7] [8] In North America, P. thaliae has been reported to cause rust in Canna indica in Florida and C. × generalis in Texas. Also reported throughout Hawaii since the 1970s. The host range of P. thaliae includes Canna indica (syn. C. edulis) and some hybrids of C. × generalis and other plants of the order Zingiberales. Moreover, P. thaliae on Canna lily was reported in South Africa. [9] [10]
Canna is a very versatile plant that has both ornamental and agronomic uses. In tropical parts of the world Canna achira , the agricultural breed of Canna, is grown for starch production in its rhizomes and fiber production in the shoots. Countries like Ecuador and Peru used to rely on Canna as a staple crop. [4] In Thailand Puccinia thaliae is listed as a medium threat to biosecurity and agriculture. [11] The Canna rust damages the crop and can impact all of its potential uses by damaging photosynthetic material and reducing plant productivity and value. In the United States it is a popular ornamental for home gardens. The rust lowers the value of lilies for sale and can kill canna plants that home gardeners are trying to grow themselves.
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.
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.
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.
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.
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.
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.
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.
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.
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