scholarly journals The Perfect Stage of Powdery Mildew of Grapevine Caused by Erysiphe necator Found in Peru

Plant Disease ◽  
2012 ◽  
Vol 96 (5) ◽  
pp. 768-768 ◽  
Author(s):  
M. V. Bendezú-Euribe ◽  
L. A. Alvarez
Keyword(s):  
Powdery Mildew ◽  
Genetic Recombination ◽  
First Record ◽  
Vitis Vinifera L ◽  
Erysiphe Necator ◽  
Host Genus ◽  
Table Grapes ◽  
Grapevine Powdery Mildew ◽  
New Races ◽  
Grape Varieties

Grapevine (Vitis vinifera L.) has been cultivated in Peru since the sixteenth century to produce wine and grape brandy called “Pisco”. Grapevine powdery mildew caused by Erysiphe necator (Schwein.) (formerly Uncinula necator [Schw.] Burr.; anamorph Oidium tuckeri) is currently the most important disease of grapevine in Peru. Table grape producers rely heavily on fungicide applications to manage powdery mildew infections. In Peru, the pathogen is normally found in the anamorphic state, except for one report of the teleomorphic state in 1972 (2) on wine grape varieties. In July 2011, ascomata were observed on table grapevine leaves cv. Sugraone in a commercial field near Huaral in the central coast of Peru. Abundant, mature (black) and immature (brown), globose ascocarps were visible on the abaxial leaf surfaces covered by the anamorphic state of the fungus. The chasmothecia were epiphyllous and ranged from 93.3 to 157.5 μm in diameter. The appendages were hyaline, variable in number (9 to 17), septate, with the apex helicoid when mature, and measuring 310 to 480 μm long. Each ascocarp contained four to seven subglobose asci (55.3 to 76.7 × 36.3 to 52.0 μm) with two to six (mostly three) ascospores. The ascospores were elliptical, hyaline, and measured 20.2 to 25.0 μm long by 11.1 to 17.3 μm wide. The pathogen was identified as E. necator on the basis of the host genus and morphology of the teleomorph (1). The teleomorphic state of E. necator could be a source of primary inoculum before infection by anamorphic conidia occurs, provide the basis for genetic recombination, and lead to more frequent appearance of new races. This could have serious implications for managing fungicide resistance in the pathogen population and may also result in the development of virulence to the resistance of some grape varieties tolerant to powdery mildew infections. In South America, the teleomorph of E. necator has been recently detected in Chile (3), and has caused great concern among grape producers. To our knowledge, this finding represents a first record of the presence of the ascigenous state of the pathogen on table grapes in Peru. References: (1) U. Braun. A Monograph of the Erysiphales (powdery mildews). J. Cramer, Berlin-Stuttgart, 1987. (2) S. L. Dongo and M. E. Arestegui. Fitopatologia 8:35, 1973. (3) F. Riveros et al. Aconex 83:24, 2004.

scholarly journals Genetic Structure and Aggressiveness of Erysiphe necator Populations during Grapevine Powdery Mildew Epidemics

2008 ◽  
Vol 74 (20) ◽  
pp. 6327-6332 ◽  
Author(s):  
Josselin Montarry ◽  
Philippe Cartolaro ◽  
François Delmotte ◽  
Jérôme Jolivet ◽  
Laetitia Willocquet
Keyword(s):  
Powdery Mildew ◽  
Latency Period ◽  
Growing Season ◽  
Spore Production ◽  
Erysiphe Necator ◽  
Genetic Groups ◽  
Grapevine Powdery Mildew ◽  
Temporal Differentiation ◽  
Group A ◽  
Group B

ABSTRACT Isolates of the causal ascomycete of grapevine powdery mildew, Erysiphe necator, correspond to two genetically differentiated groups (A and B) that coexist on the same host. This coexistence was analyzed by investigating temporal changes in the genetic and phenotypic structures of E. necator populations during three epidemics. Group A was present only at the start of the growing season, whereas group B was present throughout all three epidemics. Group A was less aggressive in terms of germination and infection efficiency but was more aggressive than group B in terms of the latency period, lesion diameter, and spore production. Our results are consistent with a temporal differentiation of niches, preventing recombination, and suggest an association between the disease level and the frequencies of genetic groups.

Release, germination, and pathogenicity of ascospores of Uncinula necator under controlled conditions

1998 ◽  
Vol 76 (5) ◽  
pp. 777-781 ◽  
Author(s):  
F Jailloux ◽  
T Thind ◽  
M Clerjeau
Keyword(s):  
Powdery Mildew ◽  
Vitis Vinifera ◽  
Storage Conditions ◽  
Vitis Vinifera L ◽  
Uncinula Necator ◽  
Grapevine Powdery Mildew ◽  
Germination Ability ◽  
Ascospore Release ◽  
Probable Role ◽  
Leaf Disks

A laboratory technique was standardized for studying the release, maturation, germination, and pathogenicity of ascospores of Uncinula necator (Schw.) Burr. Surface disinfestation and wetting of grape (Vitis vinifera L.) leaf disks bearing cleistothecia collected in the vineyard before incubation in a humid chamber for 48 h at 20°C were found essential for obtaining the release of ascospores (8 ascospores/cm2). Storage conditions involving periodic wetting treatments of cleistothecia at 5°C during 110 days were necessary to induce both ascospore release (80 ascospores/cm2) and germination ability (62%). The matured ascospores were pathogenic on healthy leaf disks at 20°C indicating their probable role as a primary inoculum source. This technique can be helpful in studying the inheritance of characteristics such as pathogenicity and fungicidal resistance.Key words: cleistothecia, ascospores, maturation, germination, pathogenicity, Uncinula necator, grapevine, powdery mildew.

scholarly journals No Indication of Strict Host Associations in a Widespread Mycoparasite: Grapevine Powdery Mildew (Erysiphe necator) Is Attacked by Phylogenetically Distant Ampelomyces Strains in the Field

2012 ◽  
Vol 102 (7) ◽  
pp. 707-716 ◽  
Author(s):  
Alexandra Pintye ◽  
Zsolt Bereczky ◽  
Gábor M. Kovács ◽  
László G. Nagy ◽  
Xiangming Xu ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Environmental Fate ◽  
Phylogenetic Analyses ◽  
Inter Simple Sequence Repeat ◽  
Issr Markers ◽  
Genetic Distances ◽  
Nuclear Ribosomal Dna ◽  
Erysiphe Necator ◽  
Grapevine Powdery Mildew ◽  
Powdery Mildew Fungi

Pycnidial fungi belonging to the genus Ampelomyces are common intracellular mycoparasites of powdery mildews worldwide. Some strains have already been developed as commercial biocontrol agents (BCAs) of Erysiphe necator and other powdery mildew species infecting important crops. One of the basic, and still debated, questions concerning the tritrophic relationships between host plants, powdery mildew fungi, and Ampelomyces mycoparasites is whether Ampelomyces strains isolated from certain species of the Erysiphales are narrowly specialized to their original mycohosts or are generalist mycoparasites of many powdery mildew fungi. This is also important for the use of Ampelomyces strains as BCAs. To understand this relationship, the nuclear ribosomal DNA internal transcribed spacer (ITS) and partial actin gene (act1) sequences of 55 Ampelomyces strains from E. necator were analyzed together with those of 47 strains isolated from other powdery mildew species. These phylogenetic analyses distinguished five major clades and strains from E. necator that were present in all but one clade. This work was supplemented with the selection of nine inter-simple sequence repeat (ISSR) markers for strain-specific identification of Ampelomyces mycoparasites to monitor the environmental fate of strains applied as BCAs. The genetic distances among strains calculated based on ISSR patterns have also highlighted the genetic diversity of Ampelomyces mycoparasites naturally occurring in grapevine powdery mildew. Overall, this work showed that Ampelomyces strains isolated from E. necator are genetically diverse and there is no indication of strict mycohost associations in these strains. However, these results cannot rule out a certain degree of quantitative association between at least some of the Ampelomyces lineages identified in this work and their original mycohosts.

scholarly journals Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

2017 ◽  
Vol 57 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Nujoud Alimad ◽  
Walid Naffaa ◽  
Fawaz Azmeh
Keyword(s):  
Powdery Mildew ◽  
Winter Season ◽  
Causal Agent ◽  
Bud Break ◽  
Erysiphe Necator ◽  
First Report ◽  
Primary Inoculum ◽  
Grapevine Powdery Mildew ◽  
Histopathological Studies ◽  
Grapevine Buds

AbstractThe main aims of this study were to determine the overwintering form and the primary inoculum ofErysiphe necator,the causal agent of grapevine powdery mildew in southern Syria. Eleven vineyards located at five different geographical sites were visited every week from March to November in 2014 and 2015. The results of field and histopathological studies showed thatE. necatorsurvived as mycelium in dormant grapevine buds during the winter season. The first flag shoots were observed shortly after bud break in spring. The number of flag shoots varied greatly according to vineyards, cultivars and years, being present on 27.4 to 61.9% of the grapevines in 2014, and on 5.2 to 40% of the grapevines in 2015. The percentage of flag shoots on the same grapevine also varied according to the year, cultivar and location. It was between 4.3 to 9.4% in 2014, and 2.1 to 3.6% in 2015. The disease was observed only on Balady and Black cultivars. Conidia were released from the second week of May to early September. The first conidia were trapped around mid-May, and the first secondary symptoms were observed on leaves from mid-May to early June according to the site. Chasmothecia were observed on leaves in 45.5% of the studied vineyards. The first observation of chasmothecia on leaves was in July, and their numbers varied greatly between vineyards and years. Chasmothecia were not detected on bark, nor were ascospores trapped at the beginning of the season. These results confirmed that the ascospores did not have any role in the initiation of spring infection. To the best of our knowledge, this is the first report of the overwintering form ofE. necatorin Syria.

scholarly journals Testing of paraffin oil efficiency against grape powdery mildew in Eger wine region

2016 ◽  
pp. 73-80
Author(s):  
Xénia Pálfi ◽  
Dénes Bisztray ◽  
Szabolcs Villangó ◽  
Zita Pálfi ◽  
Tamás Deák ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Downy Mildew ◽  
Plasmopara Viticola ◽  
Field Trials ◽  
Intensity Of Infection ◽  
Erysiphe Necator ◽  
Regular Treatment ◽  
Paraffin Oil ◽  
Wine Region ◽  
Grape Varieties

The aim of the present study was to examine the efficiency of paraffin oil against powdery mildew in Eger wine region. The experiment has been carried out in 2013 and 2014 with Chardonnay and Kékfrankos grape varieties, which have different resistance against powdery mildew. The effectiveness of the oil was examined on leaves and clusters (frequency and intensity). This oil was effective against Erysiphe necator infection on field trials in Chile and Brazil. The spread of downy mildew (Plasmopara viticola) was also inhibited by this material in some experiments conducted in Spain and France. The differences between oil treatments represented the sensitivity of the grape varieties in accordance with the applied dosages. The oil was effective against powdery mildew with different extent as a result of the so called ”vintage effect”. In 2013, the treatment of the highest dosage (D3) didn’t differed significantly in frequency and intensity of infection from the regular treatment (clusters of Kékfrankos, leaves of Chardonnay). In 2014, the oil was not so effective against powdery mildew compared to 2013. No remarkable differences were detected between the treatments due to the strong pressure of powdery mildew. Furthermore, no any effect of the lowest dosage (D1) was detected in the case of the sensitive clusters of Chardonnay and leaves of Kékfrankos in both experimental years. In summary, the oil treatment has an effect against powdery mildew, however this efficiency largely depends on the vintage characteristics and the pressure of powdery mildew. Further investigations are neccessary, for example field trials with combinations of other sprays. The oil can be useable as fungicide with proper care in eco-friendly integrated and bio (ecological) viticulture.

Isolation and identification of three new mycoparasites of Erysiphe necator for biological control of grapevine powdery mildew

2019 ◽  
Vol 48 (4) ◽  
pp. 351-367
Author(s):  
Shashikant B. Ghule ◽  
Indu S. Sawant ◽  
Sanjay D. Sawant ◽  
Sujoy Saha ◽  
R. M. Devarumath
Keyword(s):  
Biological Control ◽  
Powdery Mildew ◽  
Isolation And Identification ◽  
Erysiphe Necator ◽  
Grapevine Powdery Mildew

scholarly journals Phenolic profile and biological activity of table grapes (Vitis vinifera L.)

2019 ◽  
Vol 15 ◽  
pp. 04005
Author(s):  
C. Di Lorenzo ◽  
F. Colombo ◽  
E. Sangiovanni ◽  
S. Biella ◽  
L. Regazzoni ◽  
...  
Keyword(s):  
Biological Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Inflammatory Activity ◽  
Array Detector ◽  
Vitis Vinifera L ◽  
Positive Effects ◽  
Table Grapes ◽  
Anti Inflammatory ◽  
Grape Varieties

Table grapes are largely produced and consumed in the Mediterranean area. Furthermore, in the last years, the commercial interest in table grapes and other non-alcoholic grape products has notably increased worldwide. In addition to the nutritional aspects, polyphenol compounds in fresh grapes could exert positive effects on human health. The aim of this study was the characterization of the phenolic pattern of sixteen grape varieties and the evaluation of the associated antioxidant capacity and anti-inflammatory activity at gastric level. The methods used were: 1) Folin-Cocalteau's assay for the quantification of total polyphenol content; 2) High-Performance Liquid Chromatography (HPLC) coupled with Diode-Array Detector (DAD) to perform the quantitative analysis of grapes phenolic fraction 3) DPPH (1,1,-diphenil-2-picrylhydrazyl) spectrophotometric assay for the assessment of radical scavenging activity; 4) assessment of IL-8 release from human gastric epithelial cells to evaluate the anti-inflammatory activity of grape extracts. Some grapes, including seedless varieties, showed that the phenolic pattern was highly correlated with the biological activities, and, in particular, with peel and seeds portion. These results suggest that selected grape varieties could represent, also for consumers who do not drink wine, a source of healthy compounds potentially able to counteract oxidative stress and gastric inflammation.

scholarly journals Phenolic profile and antioxidant activity of different grape (Vitis vinifera L.) varieties

2019 ◽  
Vol 12 ◽  
pp. 04005 ◽  
Author(s):  
C. Di Lorenzo ◽  
F. Colombo ◽  
S. Biella ◽  
F. Orgiu ◽  
G. Frigerio ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
High Performance ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Mediterranean Area ◽  
Alcoholic Beverages ◽  
Vitis Vinifera L ◽  
Ionization Mass ◽  
Table Grapes ◽  
Grape Varieties

In the last years, the interest in non-alcoholic grape products has considerably increased. Table grapes are largely produced in the Mediterranean area and their consumption has raised worldwide. Beside the positive pattern of nutrients, table grapes could provide benefits on human health. Among the health-promoting substances contained in table grapes, flavonoids (mainly anthocyanins, flavan-3-ols and flavonols) seem to be the most interesting. The aim of this study was the characterization of the phenolic pattern of sixteen grape varieties, and the evaluation of the associated antioxidant activity. The methods were: 1) Folin-Cocalteau's assay for the quantification of total polyphenol content; 2) DPPH (1,1,-diphenil-2—picrylhydrazyl) assay and 3) ORAC (Oxygen Radical Absorbance Capacity) spectrophotometric assays for the assessment of radical scavenging activity; 4) High Performance Liquid Chromatography (HPLC) method, coupled with electrospray ionization mass spectrometer (ESI-MS) and DAD detector was developed in order to obtain the phenolic pattern of grape samples. Data obtained in this study underline that some table grape varieties can show interesting phenolic pattern independently from the presence or not of seeds. This observation suggests that selected varieties of seedless grapes could represent an interesting source of healthy compounds, satisfying consumers' preferences and reducing concerns versus alcoholic beverages.

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