| Erysiphe heraclei | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Leotiomycetes |
| Order: | Erysiphales |
| Family: | Erysiphaceae |
| Genus: | Erysiphe |
| Species: | E. heraclei |
| Binomial name | |
| Erysiphe heraclei | |
| Synonyms [2] | |
List
| |
Erysiphe heraclei is a plant pathogen that causes powdery mildew on several species including dill, carrot and parsley. [3]
It was originally found in 1815, on the leaves of a species of Heracleum in France. [2] It was found in Australia in New South Wales in 2007 then it spread to Tasmania and South Australia in 2008. [4]
Erysiphe heraclei is no different than your typical powdery mildew as it shares many of the important traits that make it a plant disease worth paying attention too. In the case of powdery mildew of carrots yield loss is a very typical result of an infection, as well as the reduction of the ability to mechanically pull carrots from the ground during harvest due to leaf damage. [5] The effects of yield lost are felt most with early infections, for carrots there has been a noted difference in disease expression and harshness across growing operations. In some experimental trials carrots who had no control measures against Erysiphe heraclei experience yield losses of 20%. Powdery mildew of carrots can also infect other plants as well. It has shown to infect certain celery, parsley, dill, chervil and parsnip strains as well. [6] [7]
Erysiphe heraclei causes powdery mildew of carrots. It closely follows the standard life cycle of powdery mildews. Erysiphe heraclei is considered an obligate biotroph, which means it needs a living host to survive and feeds on living plant tissue. This characteristic is an important part for why the powdery mildew life cycle is what it is. The first stage in the disease cycle starts in the spring where the overwintering inoculum become exposed to ideal conditions. The inoculum overwinter in fungal fruiting bodies called cleistothecia (OSU, 2008). [6] The cleistothecia then releases airborne spores called ascospores into the environment, which will serve as the primary inoculum during the growing season. The ascospores are then dispersed by the wind, or water where they then germinate on any leaf tissue they can find. It enters the plant by the use of a germ tube, giving the spore access to the inside of the plant. Once on the host plant another type of spore called, conidia are produced (McGrath, Cornell). The conidia then serve as the “secondary inoculum” for the disease and infect the plant further or other nearby plants for the rest of the growing season. Due to having this “secondary inoculum” this makes powdery mildew of carrots a polycyclic disease since it is able to infect further on in the growing season past the primary inoculum. The surviving conidia then overwinter and serve as primary inoculum in the spring to start the cycle all over again.
Multiple management strategies are used for the control of Erysiphe heraclei. Chemical controls are the most popular method of control and include a variety of fungicides. Common fungicides used by growers include Bravo, which provides contact control of the disease. While other fungicides provide mobile control such as Quilt, Endura, Tilt, and others (McGrath, 2013). [5] The most important aspect when it comes to applying fungicides is timing. In order for the fungicides to be as effective as possible they should be applied very early in the season and when conditions for Erysiphe heraclei are ideal (high temp, high moisture). Another key tip to remember when using fungicides is proper rotation of fungicides in order to prevent disease resistance. Aside from chemical control, mulching can also be used to minimize drought stress the plant may get during the growing season, by reducing the stress on the plant it makes it less susceptible to diseases overall. [4]
Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, as its symptoms are quite distinctive. Infected plants display white powdery spots on the leaves and stems. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant. As the disease progresses, the spots get larger and denser as large numbers of asexual spores are formed, and the mildew may spread up and down the length of the plant.
Uncinula necator is a fungus that causes powdery mildew of grape. It is a common pathogen of Vitis species, including the wine grape, Vitis vinifera. The fungus is believed to have originated in North America. European varieties of Vitis vinifera are more or less susceptible to this fungus. Uncinula necator infects all green tissue on the grapevine, including leaves and young berries. It can cause crop loss and poor wine quality if untreated. The sexual stage of this pathogen requires free moisture to release ascospores from its cleistothecia in the spring. However, free moisture is not needed for secondary spread via conidia; high atmospheric humidity is sufficient. Its anamorph is called Oidium tuckeri.
Grape black rot is a fungal disease caused by an ascomycetous fungus, Guignardia bidwellii, that attacks grape vines during hot and humid weather. “Grape black rot originated in eastern North America, but now occurs in portions of Europe, South America, and Asia. It can cause complete crop loss in warm, humid climates, but is virtually unknown in regions with arid summers.” The name comes from the black fringe that borders growing brown patches on the leaves. The disease also attacks other parts of the plant, “all green parts of the vine: the shoots, leaf and fruit stems, tendrils, and fruit. The most damaging effect is to the fruit”.
Erysiphales are an order of ascomycete fungi. The order contains one family, Erysiphaceae. Many of them cause plant diseases called powdery mildew.
Blumeria graminis is a fungus that causes powdery mildew on grasses, including cereals. It is the only species in the genus Blumeria. It has also been called Erysiphe graminis and Oidium monilioides or Oidium tritici.
Powdery mildew is a fungal disease of barley caused by Blumeria graminis f. sp. hordei. The disease has a worldwide distribution and is most damaging in cool, wet climates. The host range of the form species hordei is restricted to barley and other Hordeum species.
Erysiphe cruciferarum is a plant pathogen of the family Erysiphaceae, which causes the main powdery mildew of crucifers, including on Brassica crops, such as cauliflower, cabbage, broccoli, and Brussels sprouts. E. cruciferarum is distributed worldwide, and is of particular concentration in continental Europe and the Indian subcontinent. E. cruciferarum is an ascomycete fungus that has both sexual and asexual stages. It is also an obligate parasite that appears to have host specificity; for example, isolates from turnip will not infect Brussels sprout, and vice versa. While being a part of the family Erysiphaceae, it belongs to those members in which the conidia are formed singly and whose haustoria are multilobed.
Erysiphe betae is a fungal plant pathogen. It is a form of powdery mildew that can affect crops of sugar beet, that could cause up to a 30% yield loss. The fungus occurs worldwide in all regions where sugar beet is grown and it also infects other edible crops, e.g. beetroot.
Leptosphaeria coniothyrium is a plant pathogen. It can be found around the world.
Leveillula taurica is an obligate fungal pathogen, from the phylum Ascomycota, which causes powdery mildew on onion. This disease prefers warm, dry environments. It is rare in the United States, and is currently restricted to western states. Globally, it is also a minor problem with limited occurrences in the Middle East, Europe, and South America. L. taurica causes powdery mildew of onions, but is also known to infect other allium, solanaceous, and cucurbit species. The disease has appeared in parts of the Middle East, the Mediterranean, and South and North America. Currently, it is not a cause for major concern in the U.S. and throughout the world, as its geographic extent is sparse. In addition, it is relatively easy to control through basic sanitation and reducing water stress.
Podosphaera leucotricha is a plant pathogen that can cause powdery mildew of apples and pears.
Podosphaera macularis is a plant pathogen infecting several hosts including chamomile, caneberrie, strawberries, hop, hemp and Cineraria. It causes powdery mildew of hops.
Podosphaera pannosa is a plant pathogen. It produces a powdery mildew on members of the rose family.
Ascochyta is a genus of ascomycete fungi, containing several species that are pathogenic to plants, particularly cereal crops. The taxonomy of this genus is still incomplete. The genus was first described in 1830 by Marie-Anne Libert, who regarded the spores as minute asci and the cell contents as spherical spores. Numerous revisions to the members of the genus and its description were made for the next several years. Species that are plant pathogenic on cereals include, A. hordei, A. graminea, A. sorghi, A. tritici. Symptoms are usually elliptical spots that are initially chlorotic and later become a necrotic brown. Management includes fungicide applications and sanitation of diseased plant tissue debris.
Oidium mangiferae is a plant pathogen that infects mango trees causing powdery mildew. Powdery mildew of mango is an Ascomycete pathogen of the Erysiphales family that was initially described by Berthet in 1914, using samples collected from Brazil. O. mangiferae is found in all areas where mangoes have been raised long term, but is particularly widespread in India where both the host and the pathogen are native. Currently no teleomorph stage has been identified, but due to certain morphological characteristics it has been suggested that O. mangiferae belongs in the Erysiphe polygony group. Mango is the only known host for this pathogen, though O. mangiferae appears to be identical to fungi responsible for powdery mildew diseases on various other plant species, particularly oak, though some differences may be observed. In particular, the number of cells in conidiophores varies from 2 on mango to 3-5 on oak. O. mangiferae has been known to infect oak leaves in the laboratory, however due to the lack of a known teleomorph stage O. mangiferae is still considered to only be a pathogen of mango. Recent analysis of its ribosomal DNA suggests it is conspecific with Erysiphe alphitoides, the causative agent of powdery mildew in European oaks.
Podosphaera fuliginea is a plant pathogen that causes powdery mildew on cucurbits. Podosphaera fuliginea and Erysiphe cichoracearum are the two most commonly recorded fungi causing cucurbit powdery mildew. In the past, Erysiphe cichoracearum was considered to be the primary causal organism throughout most of the world. Today, Podosphaera fuliginea is more commonly reported.
Dibotryon morbosum or Apiosporina morbosa is a plant pathogen, which is the causal agent of black knot. It affects members of the Prunus genus such as; cherry, plum, apricot, and chokecherry trees in North America. The disease produces rough, black growths that encircle and kill the infested parts, and provide habitat for insects.
Ampelomyces quisqualis is an anamorphic fungus that is a hyperparasite of powdery mildews. This parasitism reduces growth and may eventually kill the mildew. These mycoparasites can live up to 21 days on mildew-free host plant surfaces, attacking powdery mildew structures as soon as they appear. A. quisqualis is used as the active ingredient in a commercial fungicide.
Cherry leaf spot is a fungal disease which infects cherries and plums. Sweet, sour, and ornamental cherries are susceptible to the disease, being most prevalent in sour cherries. The variety of sour cherries that is the most susceptible are the English morello cherries. This is considered a serious disease in the Midwest, New England states, and Canada. It has also been estimated to infect 80 percent of orchards in the Eastern states. It must be controlled yearly to avoid a significant loss of the crop. If not controlled properly, the disease can dramatically reduce yields by nearly 100 percent. The disease is also known as yellow leaf or shothole disease to cherry growers due to the characteristic yellowing leaves and shot holes present in the leaves upon severe infection.
Golovinomyces orontii is a species of fungus that causes powdery mildew disease and it is in the family Erysiphaceae. It is an obligate biotroph that infects plants in several families including Acanthaceae, Asteraceae, Brassicaceae, Cucurbitaceae, and Lamiaceae.
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