Blumeria graminis (powdery mildew of grasses and cereals).

2021 ◽  
Author(s):  
Christina Cowger ◽  
James K. M. Brown
Keyword(s):  
Powdery Mildew ◽  
Northern Hemisphere ◽  
Cropping System ◽  
Limiting Factor ◽  
Yield Losses ◽  
Powdery Mildews ◽  
Cereal Species ◽  
The World ◽  
Cereal Production ◽  
Tropical Areas

Abstract Powdery mildew is one of the most common and destructive diseases of cereals. Actual losses depend on the time of disease epidemic onset and its severity, and can at the extreme reach up to 60% (James et al., 1991; Oerke et al., 1994). Although it occurs in most, if not all, parts of the world where cereals are grown, powdery mildew is not considered to be a major problem in every region. This disease can be very destructive, but generally seems to cause most damage in temperate latitudes, especially in the northern hemisphere, where wheat and barley are more frequently cultivated (see map in Cowger et al., 2012). However, powdery mildew can also be a limiting factor for cereal production in subtropical and tropical areas. Yield losses by powdery mildews are generally complex to estimate and depend on several factors such as climate, year, cropping system, cereal species and cultivar.

scholarly journals Blumeria graminis (powdery mildew of grasses and cereals).

2021 ◽  
Author(s):  
Christina Cowger ◽  
James K. M. Brown
Keyword(s):  
Powdery Mildew ◽  
Northern Hemisphere ◽  
Cropping System ◽  
Limiting Factor ◽  
Yield Losses ◽  
Powdery Mildews ◽  
Cereal Species ◽  
The World ◽  
Cereal Production ◽  
Tropical Areas

Abstract Powdery mildew is one of the most common and destructive diseases of cereals. Actual losses depend on the time of disease epidemic onset and its severity, and can at the extreme reach up to 60% (James et al., 1991; Oerke et al., 1994). Although it occurs in most, if not all, parts of the world where cereals are grown, powdery mildew is not considered to be a major problem in every region. This disease can be very destructive, but generally seems to cause most damage in temperate latitudes, especially in the northern hemisphere, where wheat and barley are more frequently cultivated (see map in Cowger et al., 2012). However, powdery mildew can also be a limiting factor for cereal production in subtropical and tropical areas. Yield losses by powdery mildews are generally complex to estimate and depend on several factors such as climate, year, cropping system, cereal species and cultivar.

scholarly journals Taxonomy and phylogeny of the Erysiphe lonicerae complex (Helotiales, Erysiphaceae) on Lonicera spp.

2020 ◽  
Author(s):  
M. Bradshaw ◽  
U. Braun ◽  
M. Götz ◽  
S. Takamatsu
Keyword(s):  
Powdery Mildew ◽  
Northern Hemisphere ◽  
Phylogenetic Analyses ◽  
Lonicera Japonica ◽  
Separate Species ◽  
New Name ◽  
Powdery Mildews ◽  
Wide Range ◽  
The World

The phylogeny and taxonomy of powdery mildews, belonging to the genus Erysiphe, on Lonicera species throughout the world are examined and discussed. Phylogenetic analyses revealed that sequences retrieved from Erysiphe lonicerae, a widespread powdery mildew species distributed in the Northern Hemisphere on a wide range of Lonicera spp., constitutes a complex of two separate species, viz., E. lonicerae (s. str.) and Erysiphe ehrenbergii comb. nov. Erysiphe lonicerae occurs on Lonicera spp. belonging to Lonicera subgen. Lonicera (= subgen. Caprifolium and subgen. Periclymenum), as well as L. japonica. Erysiphe ehrenbergii comb. nov. occurs on Lonicera spp. of Lonicera subgen. Chamaecerasus. Phylogenetic and morphological analyses have also revealed that Microsphaera caprifoliacearum (≡ Erysiphe caprifoliacearum) should be reduced to synonymy with E. lonicerae (s. str.). Additionally, Erysiphe lonicerina sp. nov. on Lonicera japonica in Japan is described and the new name Erysiphe flexibilis, based on Microsphaera lonicerae var. flexuosa, is introduced. The phylogeny of Erysiphe ehrenbergii and E. lonicerae as well as other Erysiphe species on honeysuckle is discussed, and a survey of all species, including a key to the species concerned, is provided.

scholarly journals Resistance Potential to Powdery Mildew (Microsphaera diffusa Cooke and Peck) of Several Yellow and Black Soybean (Glycine max (L.) Merr) Genotypes

2017 ◽  
Vol 2 (6) ◽  
pp. 270 ◽  
Author(s):  
Endah Yulia ◽  
Fitri Widiantini ◽  
Agung Karuniawan ◽  
Rudolf Comoc
Keyword(s):  
Powdery Mildew ◽  
Block Design ◽  
Limiting Factor ◽  
Yield Losses ◽  
Black Soybean ◽  
Potential Source ◽  
Randomized Block Design ◽  
Soybean Genotypes ◽  
Glycine Max L ◽  
Soybean Resistance

Powdery mildew caused by Microsphaera diffusa has recently received more attention because of yield losses caused by the disease and has even been reported as a limiting factor on soybean production in a certain soybean plantation areas. The aim of the research was to examine resistance potential of several yellow and black soybean genotypes in order to develop powdery mildew-resistant soybean varieties. The experiment was conducted in rainy season of 2013 at the Ciparanje Experimental Station, Faculty of Agriculture, Universitas Padjadjaran, Jatinangor, West Java, using a Randomized Block Design with 61 soybean genotypes as treatments that replicated two times. Each genotype was planted in plot (5 m long) consisted of 25 plants from which 6 plants per plot were sampled randomly. The disease intensity and soybean yield were assessed. The result showed that 15 genotypes were not infected by the disease, namely UP-104, UP-106, UP-108, UP-111, UP-112, UP-113, UP-114, UP-125, UP-127, UP-130, UP-136, UP-137, Argomulyo, Arjasari and Mintani, whereas other 46 genotypes were infected with the highest disease intensity of around 40%. Genotypes showing resistance potential are considered as a potential source of resistance genes that valuable in the disease-resistant soybean breeding. Keywords: Soybean; resistance; powdery mildew; Microsphaera diffusa

scholarly journals First Report of Powdery Mildew Caused by Golovinomyces asterum var. solidaginis on Invasive Weed Solidago gigantea in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1120-1120 ◽  
Author(s):  
S. E. Cho ◽  
J. H. Park ◽  
S. H. Hong ◽  
H. D. Shin
Keyword(s):  
North America ◽  
Powdery Mildew ◽  
Morphological Characteristics ◽  
Width Ratio ◽  
Limiting Factor ◽  
Indigenous Plants ◽  
Invasive Weed ◽  
First Report ◽  
Solidago Gigantea ◽  
Powdery Mildews

Solidago gigantea Aiton (syn. S. serotina Aiton), known as giant goldenrod, is native to North America and has been invasive in Europe and Asia. In Korea, this plant was accidentally introduced around the 1960s and has become widely naturalized by replacing indigenous plants and disrupting the native ecosystem (3). In October 2012, hundreds of giant goldenrod plants growing wild in riverine areas and roadsides were found affected by a powdery mildew in Busan, Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Symptoms first appeared as circular to irregular white patches, which subsequently showed abundant hyphal growth on both sides of the leaves. Appressoria on the mycelium were nipple-shaped to moderately lobed. Conidiophores measured 120 to 240 × 10 to 12.5 μm, were arising laterally from hyphal mother cells, and produced 2 to 6 immature conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells in conidiophores were 42 to 70 μm long and characterized by a distinctly curved base. Conidia were hyaline, ellipsoid to ovate, measured 28 to 42 × 17 to 24 μm (length/width ratio = 1.4 to 2.1), contained small oil drops, lacked distinct fibrosin bodies, and produced germ tubes on the subterminal position. No chasmothecia were observed. The morphological characteristics described above were typical of the Euoidium type anamorph of the genus Golovinomyces, and the fungus measurements and structures were consistent with those of G. asterum var. solidaginis U. Braun (1). To confirm the identity of the causal fungus, the complete ITS region of rDNA from isolate KUS-F27219 was amplified with primers ITS5 and P3 (4) and sequenced. The resulting 508-bp sequence was deposited in GenBank (Accession No. KC513763). A GenBank BLAST search of this sequence revealed >99% similarity with the ITS sequences of G. cichoracearum from Australia (GQ183940 ex Solidago sp.) and Japan (AB077625 ex S. altissima L. and AB077627 ex S. virgaurea subsp. asiatica Kitam. ex Hara). The G. cichoracearum isolates on Solidago spp. listed above are now placed in G. asterum var. solidaginis (1). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of five healthy potted giant goldenrods. Five non-inoculated plants served as controls. Plants were maintained in a greenhouse at 24 to 30°C. Inoculated plants developed signs and symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on inoculated plants was morphologically identical to that originally observed, fulfilling Koch's postulates. Association of S. gigantea with Golovinomyces powdery mildews has been known in North America, South America, Europe, New Zealand, Central Asia (Iran, Kazakhstan, and Kyrgyzstan), and Japan (2). To our knowledge, this is the first report of powdery mildew caused by G. asterum var. solidaginis on S. gigantea in Korea. Our field observations suggest that the powdery mildew could be a limiting factor to suppress the expansion of this invasive weed in Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved January 22, 2013. (3) S. M. Oh et al. Kor. J. Weed Sci. 22:280, 2002. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

scholarly journals Genome-wide identification of the oat MLO family and identification of a candidate AsMLO associated with powdery mildew susceptibility

2021 ◽  
Author(s):  
Aisling Reilly ◽  
Hesham A.Y. Gibriel ◽  
Sujit Jung Karki ◽  
Tony Twamley ◽  
John Finnan ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Avena Sativa ◽  
Gene Expression Analysis ◽  
Limiting Factor ◽  
Yield Losses ◽  
Loss Of Function ◽  
Genome Wide ◽  
Susceptibility Factors ◽  
Broad Spectrum Resistance ◽  
Disease Pressure

Blumeria graminis f. spp. avenae, is the causal agent of powdery mildew disease in oats (Avena sativa). It is the most significant limiting factor to oat production, with yield losses ranging from 5%-40%, during high disease pressure conditions. Certain members of the Mildew Locus O (MLO) gene family have been shown to act as powdery mildew susceptibility factors in many different plant species. A loss-of-function mutation of specific MLO genes confers broad-spectrum resistance against powdery mildew pathogens. Potential MLO candidates have not yet been identified in oats. In this study, we identified oat MLOs by querying 341 known MLO protein sequences against the publicly available oat genome. 11 MLO-like sequences were identified in oats. Phylogenetic analysis grouped these candidates into four different clades, one of which, AsMLO1 was grouped together with other cereal MLOs functionally known to contribute to powdery mildew susceptibility. AsMLO1 showed the highest similarity to the known powdery mildew-associated MLO proteins from wheat and barley. Gene expression analysis revealed AsMLO1 expression is up regulated at 12 hours post-infection with Bga and was inferred to be a candidate gene associated with powdery mildew susceptibility in oats. These results are an important step towards more durable strategies to control powdery mildew incidence and severity in oats.

Microscopy studies of powdery mildew on summer squash

1991 ◽  
Vol 49 ◽  
pp. 520-521
Author(s):  
John S. Gardner ◽  
W. M. Hess
Keyword(s):  
Powdery Mildew ◽  
Tip Growth ◽  
Hyphal Growth ◽  
Plant Tissues ◽  
Vegetative Hypha ◽  
Powdery Mildews ◽  
Summer Squash ◽  
Conidial Formation ◽  
Polar Tip Growth ◽  
Short Conidiophore

Powdery mildews are characterized by the appearance of spots or patches of a white to grayish, powdery, mildewy growth on plant tissues, entire leaves or other organs. Ervsiphe cichoracearum, the powdery mildew of cucurbits is among the most serious parasites, and the most common. The conidia are formed similar to the process described for Ervsiphe graminis by Cole and Samson. Theconidial chains mature basipetally from a short, conidiophore mother-cell at the base of the fertile hypha which arises holoblastically from the conidiophore. During early development it probably elongates by polar-tip growth like a vegetative hypha. A septum forms just above the conidiophore apex. Additional septa develop in acropetal succession. However, the conidia of E. cichoracearum are more doliform than condia from E. graminis. The purpose of these investigations was to use scanning electron microscopy (SEM) to demonstrate the nature of hyphal growth and conidial formation of E. cichoracearum on field-grown squash leaves.

Incidence of powdery mildew on cucurbit plants in Katsina, Nigeria

2019 ◽  
pp. 05-09
Keyword(s):  
Powdery Mildew ◽  
Low Cost ◽  
Frequency Of Occurrence ◽  
Sphaerotheca Fuliginea ◽  
Causal Organism ◽  
Powdery Mildews ◽  
Powdery Mildew Disease ◽  
Important Disease

The presence study deals with powdery mildews in various cucurbits in Katsina city (Barhim Estate, Kofar Durbi, Kofar Sauri, Kofar Marusa and Low Cost), Nigeria. The finding shows that the areas infested with powdery mildew is one of the important disease of cucurbits. The Sphaerotheca fuliginea was identified to be the causal organism present on all observed cucurbits in the study. Highest frequency of disease was found in Kofar Sauri(79%) fallowed by Kofar Marusa (68%), Kofar Durbi (66%), Barhim Estate (65%) and the lowest frequency of occurrence of disease was found in Low Cost (55%).The intensity of the disease was moderate to severe in general but it was high in many fields, the area-wise variation was also noticed. On vegetables, the highest frequency of occurrence of powdery mildew disease was observed on L. cylindrica (76.4%) followed by C. moschata (60%), C. sativus (59.3%), C. vulgaris (53.9%) and lowest was found on C. melo (44.4%). The highest intensity of disease was found on C. moschata, followed by L. cylindrica, C. sativus, C. vulgaris and C. melo.

Changing Composition and Growth Performance of Services Sector in India after Liberalization

2020 ◽  
pp. 432-436
Keyword(s):  
Growth Rate ◽  
Growth Performance ◽  
Direct Investment ◽  
Service Sector ◽  
World Market ◽  
Limiting Factor ◽  
Arunachal Pradesh ◽  
Services Sector ◽  
State Economy ◽  
The World

This present study makes an analysis of changing contribution of sub-sector and composition and growth performance in Indian economy. In addition to that, the contribution of sub-sector of service sector in state economy. The results revealed that the growth rate of Chandigarh was high due to providing especial emphasis on dominating sub-sectors of services and its most preferred destination for technology whereas, Sikkim and Arunachal Pradesh due to geographical and environmental conditions development were higher in floriculture and agriculture, although, tourism emerged as a new profession and have different opportunities. Apart of that, in the wake of some challenges in the form of lack of infrastructure, recent crisis in the world market, foreign direct investment (FDI) restrictions and outsourcing backlash were major limiting factor.

scholarly journals Traditional uses, phytochemistry, pharmacology and toxicity of Arisaema (Areaceae): a review

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Heena Ali ◽  
Ubaid Yaqoob
Keyword(s):  
Skin Irritation ◽  
Clinical Applications ◽  
Human Populations ◽  
Main Body ◽  
Anticancer Activities ◽  
Medicinal Uses ◽  
The World ◽  
Different Types ◽  
Tropical Areas ◽  
Medicinal Properties

Abstract Background The genus Arisaema (Areaceae), popularly known as cobra lilies and jack in pulpit is mainly found in temperate to tropical areas of all continents except South America, Europe and Australia and contain about more than 250 species. Arisaema genus is being used by the different folks of human populations for medicinal as well as food purposes. Arisaema plants are used for the treatment of different types of diseases. There have been several attempts to highlight different aspects of genus Arisaema by describing it in terms of phytochemistry and medicinal uses. The present study is, however, an attempt to put together all the former data available related to the phytochemistry and medicinal uses of genus Arisaema. Main body The phytochemicals of the plant include alkaloids, phenols, terpenes, flavonoids, lectins, saponins, glycosides, triterpenoids, stigmasterols, n-alkanes, n-alkanols sitosterols, campesterol, oxalates, coumarins, tannins etc. Moreover, the properties such as antioxidant, antifungal, antibacterial, insecticidal, antimicrobial, cytotoxic, nematocidal, antiallergic antitumour and anticancer activities are also shown by the plants belonging to genus Arisaema. Arisaema plants have been traditionally used to treat various ailments such as resolving phlegm, dampness, and to treat asthma, bronchitis, cold, cough, and laryngitis etc. It has been found that there are several species which are toxic by nature. The development of clinical applications of arisaematis rhizomes had been seriously constrained due to its toxic properties like, mouth and lingua pain, even respiration slowing and suffocation, mucous membrane and skin irritation etc. and this toxicity of arisaematis rhizomes is due to raphide components. Conclusions The collection of data available on the phytochemistry of genus Arisaema is not sufficient as further work is required to do on phytochemical and medicinal basis. The data available on phytochemistry and medicinal properties of the plants belonging to genus Arisaema throws light on various species of Arisaema which are medicinally important and have been exploited to treat different types of diseases in the world.

scholarly journals Further Support of Conspecificity of Oak and Mango Powdery Mildew and First Report of Erysiphe quercicola and Erysiphe alphitoides on Mango in Mainland Europe

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1086-1093 ◽  
Author(s):  
Marie-Laure Desprez-Loustau ◽  
Marie Massot ◽  
Nicolas Feau ◽  
Tania Fort ◽  
Antonio de Vicente ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Host Range ◽  
Molecular Mechanisms ◽  
Single Copy ◽  
Broad Host Range ◽  
First Report ◽  
Erysiphe Quercicola ◽  
Powdery Mildews ◽  
Mango Leaves ◽  
Practical Implications

Mango leaves and inflorescences infected by powdery mildew in southern Spain were analyzed using multigene sequencing (ITS + 4 single-copy coding genes) to identify the causal agent. Erysiphe quercicola was detected in 97% out of 140 samples, collected in six different orchards in the Malaga region. Among these, a small proportion also yielded E. alphitoides (8% of all samples) and E. alphitoides was found alone in 3% of samples. A phylogenetic approach was completed by cross inoculations between oak and mango, which led to typical symptoms, supporting the conspecificity of oak and mango powdery mildews. To our knowledge, this is the first report of E. quercicola and E. alphitoides causing powdery mildew on mango trees in mainland Spain, and thus mainland Europe, based on unequivocal phylogenetic and biological evidence. Our study thus confirmed the broad host range of both E. quercicola and E. alphitoides. These results have practical implications in terms of the demonstrated ability for host range expansion in powdery mildews. They also open interesting prospects to the elucidation of molecular mechanisms underlying the ability to infect single versus multiple and unrelated host plants since these two closely related powdery mildew species belong to a small clade with both generalist and specialist powdery mildews.

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