Puccinia schedonnardi ist eine Ständerpilzart aus der Ordnung der Rostpilze (Pucciniales). Der Pilz ist ein Endoparasit von Malvengewächsen sowie diverser Süßgräser. Symptome des Befalls durch die Art sind Rostflecken und Pusteln auf den Blattoberflächen der Wirtspflanzen. Sie ist in Amerika und Ostasien verbreitet.
Puccinia schedonnardi ist mit bloßem Auge nur anhand der auf der Oberfläche des Wirtes hervortretenden Sporenlager zu erkennen. Sie wachsen in Nestern, die als gelbliche bis braune Flecken und Pusteln auf den Blattoberflächen erscheinen.
Das Myzel von Puccinia schedonnardi wächst wie bei allen Puccinia-Arten interzellulär und bildet Saugfäden, die in das Speichergewebe des Wirtes wachsen. Die systemisch wachsenden Aecien des Pilzes besitzen 20–24 × 16–19 µm große, ellipsoide bis kugelige, hyaline Aeciosporen mit runzliger Oberfläche. Die zimtbraunen Uredien der Art wachsen beidseitig auf den Blättern der Wirtspflanze. Ihre hell zimtbraunen Uredosporen sind 21–26 × 18–24 µm groß und fein stachelwarzig. Die beidseitig wachsenden Telien der Art sind schwärzlich, pulverig und früh offenliegend. Die hell haselnussbraunen Teliosporen des Pilzes sind zweizellig, selten vertikal septiert, in der Regel langellipsoid bis ellipsoid und 28–26 × 18–25 µm groß. Ihr Stiel ist meist farblos und bis zu 125 µm lang.
Das bekannte Verbreitungsgebiet von Puccinia schedonnardi reicht von Argentinien bis in die nördlichen USA und umfasst zudem Japan und die Philippinen.
Die Wirtspflanzen von Puccinia schedonnardi sind für den Haplonten vor allem Hibiscus-Arten und andere Malvengewächse (Malvaceae spp.) sowie Süßgräserd er Gattungen Lycurus, Melica, Muhlenbergia, Schedonnardus, Sporobolus und Diplasis für den Dikaryonten. Der Pilz ernährt sich von den im Speichergewebe der Pflanzen vorhandenen Nährstoffen, seine Sporenlager brechen später durch die Blattoberfläche und setzen Sporen frei. Die Art verfügt über einen Entwicklungszyklus mit Telien, Uredien, Spermogonien und Aecien und macht einen Wirtswechsel durch.
Puccinia schedonnardi ist eine Ständerpilzart aus der Ordnung der Rostpilze (Pucciniales). Der Pilz ist ein Endoparasit von Malvengewächsen sowie diverser Süßgräser. Symptome des Befalls durch die Art sind Rostflecken und Pusteln auf den Blattoberflächen der Wirtspflanzen. Sie ist in Amerika und Ostasien verbreitet.
Puccinia schedonnardii is a basidiomycete fungus that affects cotton.[1] 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.
For Puccinia schedonnardii the host range is specific to cotton, but is not specific to a certain cotton species. Alternate hosts are necessary to complete the life cycle, and include many types of gramma grasses. Symptomology is similar to that of other rust species. First appearing as small yellow pustules on leaves, bolls, and stems, the spots will then transform into larger, orange/red pustules[2] which release aeciospores.[3] Rust lesions can cause leaves or stems to become weak and break or fall off, resulting in decreased photosynthetic ability and extreme difficulty during harvest. Symptoms on the alternate host grasses are small ovular red/brown (rust colored) powdery lesions, which release uredospores.
The disease cycle of Puccinia schedonardii does not vary from other rust disease cycles. This pathogen is heteroecious and exhibits a polycyclic disease cycle. Puccinia schedonnardii overwinters as teliospores that are produced in telia on the alternate host. In the spring, the teliospores germinate to produce basidiospores. The basidiospores are then windblown to the cotton host where they enter via stomata. When basidiospores germinate, they produce a mycelium from which flask-shape pycnia as well as receptive hyphae are formed. From here, nothing happens until the pycniospores produced by the pycnia fertilize receptive hyphae of a different mating type. Over a period of five to ten days the dikaryotic mycelia formed by the joining of the receptive hyphae and the pycniospore grows through the cotton leaf to produce aecia. Aecia are the pustules seen on the leaves of the cotton. When conditions are right, and adequate moisture is achieved, aeciospores are released from the aecia. These aeciospores land on the alternate grass host and infect it via a germ tube.[4] Eventually, a uredium is formed from this germ tube. The uredospores released by the uredium are then able to do one of two things. As a polycyclic disease, the uredospores present an opportunity for secondary infection in a single season. The spores can either reinfect grasses by spreading uredospores that become uredia which leads to more uredospores and a likely epidemic; or they can become overwintering teliospores, thus preparing for the cycle to begin again in the spring.[5]
Rust infections can proliferate under humid conditions and periods of prolonged wetness. Ideally, periods of 1 inch (25 mm) or more of rain followed by at least 12 hours of high humidity are needed for the disease to develop.[4] It is the moisture on the leaf surfaces that leads to disease and spore release/germination, so even well drained soils are susceptible to rust outbreaks. However, evidence has shown that poorly-drained soils may have increased incidence of fungal pathogens like rust, due to the increased relative humidity underneath the canopy.[6]
Disease management can be difficult as it would be impossible to eliminate the alternate host grass species. However, the utilization of non-susceptible crops in a rotation can decrease infection rate in future cotton crops. An application of Mancozeb foliar fungicide can be used to prevent the disease,[4] but little can be done after infection. This is not effective as a treatment, only as a prevention tool. Similarly, growers are proactive in their prevention of the disease, ensuring the proper fungicide applications.
As previously stated, the importance of this disease can be severe, but growers tend to plant resistant varieties in areas where rust has been prevalent. One common cultivar with transferred resistance is Gossypium hirsutum, which was transferred from G. arboretum and G. anomalum.[7] Without resistance, Puccinia schedonnardii can cause a 50% yield loss, which is why generally resistant varieties are so widely used. Cotton is one of the most important textile fibers, and the United States is ranked third in cotton production.[8] It is for that reason that such a large focus of agronomic research funding has gone to cotton research to develop solutions to cotton rust.
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 schedonnardii je grzib[3], co go ôpisoł Kellerm. & Swingle 1888. Puccinia schedonnardii nŏleży do zorty Puccinia i familije Pucciniaceae.[4][5] Żŏdne podgatōnki niy sōm wymianowane we Catalogue of Life.[4]
Wikispecies mo informacyje ô Puccinia schedonnardii.Puccinia schedonnardii je grzib, co go ôpisoł Kellerm. & Swingle 1888. Puccinia schedonnardii nŏleży do zorty Puccinia i familije Pucciniaceae. Żŏdne podgatōnki niy sōm wymianowane we Catalogue of Life.
