| Erysiphales | |
|---|---|
 | |
| Powdery mildew | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Leotiomycetes |
| Order: | Erysiphales H.Gwynne-Vaughan, 1922 |
| Family: | Erysiphaceae Tul. & C.Tul., 1861 |
| Genera [1] | |
Genera (See Text) | |
Erysiphales are an order of ascomycete fungi. The order contains one family, Erysiphaceae. Many of them cause plant diseases called powdery mildew.
The order contains one family (Erysiphaceae), 28 genera and around 1000 species. [2] Many imperfect fungi (fungi whose sexual reproduction is unknown) belong here, especially the genus Oidium . Recent molecular data have revealed the existence of six main evolutionary lineages. Clade 1 consists of Erysiphe , Microsphaera , and Uncinula , all of which have an Oidium subgenus Pseudoidium mitosporic state. Clade 2 consists of Erysiphe galeopsidis and Erysiphe cumminsiana (anamorphs in Oidium subgenus Striatoidium). Clade 3 consists of Erysiphe species with anamorphs in Oidium subgenus Reticuloidium. Clade 4 consists of Leveillula and Phyllactinia, which have Oidiopsis and Ovulariopsis mitosporic states, respectively. Clade 5 consists of Sphaerotheca , Podosphaera, and Cystotheca, which have Oidium subgenera Fibroidium and Setoidium mitosporic states. Clade 6 consists of Blumeria graminis , which has an Oidium subgenus Oidium mitosporic state. Several morphological characters have been analysed and found not to conflict with the molecular data.
The cleistothecia are minute, usually not much more than 0.1 millimetres (1⁄256 in) in diameter. From the outer wall of the cleistothecium specialised hyphae (appendages) grow out. The number of asci per ascoma varies, and is important in discriminating between genera.
The infection of the host plant begins with the sexual ascospores, or the asexual conidia germinating on the surface of the plant's leaf or stem, resulting in septate mycelium of uninucleate cells. In most powdery mildews only the epidermal cells are attacked. The external mycelium gives rise to short, erect conidiophores, each of which bears a single row of barrel-shaped spores, the youngest being at the base (the affected parts become thus covered with a forest of conidiophores assuming a white powdery appearance). The ripe spores become detached and are readily dispersed by the wind, causing fresh infection. In autumn the sexual cleistothecia are produced. The cleistothecia represent the resting (hibernating) stage of the pathogen. The ascospores remain dormant all winter to germinate in spring. When the asci expand they rupture the cleistothecia wall, throwing the ascospores into the air.
Erysiphales are obligate parasites on leaves and fruits of higher plants, causing diseases called powdery mildews. Most attempts to grow them in culture have failed. [3]
Erysiphales have a nearly cosmopolitan distribution, [4] and have developed fungicide resistance just as widely. [5] Total loss of function has resulted in some cases. [5] Resistance management planning, use of multi-mode of action fungicides, and altered frequency and quantity of application are needed to slow the progress of resistance. [5]
As accepted by Wijayawardene et al. 2020 (with amount of species); [2]
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 the signs of the causal pathogen are quite distinctive. Infected plants display white powdery spots on the leaves and stems. This mycelial layer may quickly spread to cover all of the leaves. 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.
Oidium is a genus of Deuteromycetes, where traditionally most anamorphs of the order Erysiphales are included. Most of them are plant pathogens causing different forms of powdery mildew, for example:
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.
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.
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.
Brasiliomyces malachrae is a species of fungus in the family Erysiphaceae. It is a plant pathogen that grows on Gossypium, Lavatera assurgentiflora, Malachra capitata, Malvastrum coromandelianum, and species of Malvaceae. It is found in South America.
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.
Phyllactinia guttata is a species of fungus in the family Erysiphaceae; the anamorph of this species is Ovulariopsis moricola. A plant pathogen distributed in temperate regions, P. guttata causes a powdery mildew on leaves and stems on a broad range of host plants; many records of infection are from Corylus species, like filbert and hazel. Once thought to be conspecific with Phyllactinia chorisiae, a 1997 study proved that they are in fact separate species.
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.
Erysiphe is a genus of fungi in the family Erysiphaceae. Many of the species in this genus are plant pathogens which cause powdery mildew.
Uncinula is a genus of fungi. Its species are plant pathogens that cause powdery mildew diseases on various plant hosts. The genus is characterized by its dark chasmothecia which bear filamentous, hyaline appendages with hooked tips. Over one hundred species have been described from mostly dicotyledenous hosts. Braun and Takamatsu (2000) suggested that Uncinula should be considered a later synonym of Erysiphe; not all subsequent researchers have accepted their conclusions.
Phyllactinia is a genus of fungi in the family Erysiphaceae. The type species was Phyllactinia suffulta, which is now the synonym for Phyllactinia guttata.
Erysiphe alphitoides is a species of fungus which causes powdery mildew on oak trees.
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.
Podosphaera filipendulae is a fungal species that belongs to the genus Podosphaera and the order Erysiphaceae. It was first described with meadowsweet as the host plant.
Erysiphe azerbaijanica is a species of powdery mildew in the family Erysiphaceae. It is found in Azerbaijan, where it grows on the leaves of sweet chestnut trees.
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.
