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.

scholarly journals The occurrence of Fusarium poae (Peck) Wollenw. on oat (Avena sativa L.) panicles and its harmfulness

2012 ◽  
Vol 65 (4) ◽  
pp. 169-178 ◽  
Author(s):  
Irena Kiecana ◽  
Małgorzata Cegiełko ◽  
Elżbieta Mielniczuk ◽  
Juliusz Perkowski
Keyword(s):  
Plant Breeding ◽  
Avena Sativa ◽  
Growing Season ◽  
Field Observations ◽  
Breeding Line ◽  
Head Blight ◽  
Fusarium Poae ◽  
Group A ◽  
Group B ◽  
The City

Field observations of oat panicles carried out in the fields of Danko Plant Breeding Company in the period 2006–2007 and in the fields of Strzelce Plant Breeding Company in 2008 showed the occurrence of panicles with <em>Fusarium </em>head blight symptoms in each growing season. In 2006 the percentage of such panicles ranged from 0.25 to 1.5%, in 2007 from 2.0 to 9.0%, whereas in 2008 from 0.5 to 8.0%. The species <em>Fusarium poae </em>was the main causal agent of <em>Fusarium </em>head blight. A study on inoculation of panicles of 12 genotypes of oats with <em>Fusarium poae </em>strain no. 35, which was conducted in 2008 in experimental fields near the city of Zamość, determined the number of kernels per panicle, grain yield from 40 panicles (4×10 panicles), and 1000-kernels weight (TKW) after the harvest of the crop at full grain maturity. Compared to the control, the lowest reduction in the number of kernels per panicle was found in the case of the cultivar 'Krezus' (88.69% of the control), while the highest one in 'Szakal' (22.46% of the control). As a result of inoculation of panicles with <em>F. poae</em>, the breeding line STH 8107 was characterized by the lowest decrease in kernels yield (69.76% of the control), whereas the highest decrease was found in the breeding line CHD 1430/02 (14.26% of the control). Compared to the control, the lowest reduction in TKW was observed in the breeding line STH 8107 (96.46% of the control), whereas the highest one in the breeding line CHD 1430/02 (45.06% of the control). The presence of secondary metabolites of <em>F. poae </em>and group A trichothecene compounds: HT-2 toxins (from 0 to 0.013 mg × kg<sup>-1</sup>), diacetoxyscirpenol (DAS) (from 0 to 0.002 mg × kg<sup>-1</sup>), T-2 tetraol (from 0.001 to 0.014 mg x g<sup>-1</sup>), and scirpentriol (from 0.008 to 0.074 mg × kg<sup>-1</sup>), was found in infected oat kernels. Group B trichothecenes: nivalenol (from 0 to 0.157 mg × g<sup>-1</sup>), deoxynivalenol (DON) (from 0 to 0.127 mg × kg<sup>-1</sup>) as well as its acetylated derivatives: 3-AcDON (from 0 to 0.059 mg × kg<sup>-1</sup>) and 15-Ac DON (from 0 to 0.288 mg × kg<sup>-1</sup>), were also present in oat kernels obtained from panicles artificially infected with <em>Fusarium poae</em>.

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.

Interruption and Reduction of Erysiphe necator Chasmothecia Development Utilizing Fungicidal Oil

2018 ◽  
Vol 19 (2) ◽  
pp. 153-155
Author(s):  
L. D. Thiessen ◽  
T. M. Neill ◽  
W. F. Mahaffee
Keyword(s):  
Powdery Mildew ◽  
Disease Incidence ◽  
Growing Season ◽  
Management Option ◽  
Erysiphe Necator ◽  
Grape Powdery Mildew

Grape powdery mildew epidemics, caused by Erysiphe necator, are initiated by the release and subsequent germination of ascospores from mature chasmothecia. Interrupting the development of chasmothecia prior to overwintering may reduce or prevent the overwintering of E. necator in vineyards, thereby reducing initial disease incidence observed the following growing season. At the end of the grape growing season in 2014 and 2015, one application of Organic JMS Stylet Oil (Vero Beach, FL) at a rate of 10 ml/liter was applied on four treatment dates using an air-assisted backpack sprayer onto Chardonnay grapevines within a vineyard. Leaves were collected weekly and chasmothecia enumerated from the first observation of chasmothecia primordia development until the onset of rains (approximately 5 weeks). In 2014, all stylet oil treatment plots developed significantly fewer chasmothecia than nontreated control plots in 2014 (P = 0.04), and there were no differences in treatment date observed. No treatment differences were observed in 2015. Because chasmothecia were still produced despite stylet oil treatment, a single post-véraison stylet oil application to interrupt chasmothecia development would not be an economical management option for reduction of grape powdery mildew.

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 Diagnostic Potential of Evaluation of SDF-1αand sRAGE Levels in Threatened Premature Labor

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Rafał Rzepka ◽  
Barbara Dołęgowska ◽  
Aleksandra Rajewska ◽  
Daria Sałata ◽  
Marta Budkowska ◽  
...  
Keyword(s):  
Preterm Birth ◽  
Latency Period ◽  
Neonatal Morbidity ◽  
Diagnostic Value ◽  
Cervical Length ◽  
Ultrasound Measurement ◽  
Premature Labor ◽  
Diagnostic Potential ◽  
Group A ◽  
Group B

Preterm birth remains the most prevalent cause of neonatal morbidity. This study aimed to evaluate the diagnostic value of SDF-1α, resistin, secretory RAGE (sRAGE), and endogenous secretory RAGE (esRAGE) in preterm labor. A total of 211 pregnant women participated in the study. Group A contained 72 women between 22 and 36 weeks of gestation, with premature labor, who finally had preterm birth. Group B contained 66 women in labor between 37 and 41 weeks of gestation. Women in group A had lower SDF-1αand sRAGE levels than those in group B. Moreover, in group A, SDF-1αand sRAGE levels were correlated with the latency period from the occurrence of premature labor symptoms until delivery. Sensitivity and specificity of studied parameters for prediction of preterm birth were 95% and 40% for SDF-1αand 51.3% and 93.5% for sRAGE, respectively. The prognostic value of plasma SDF-1αand sRAGE levels was comparable with that of cervical length ultrasound measurement and serum C-reactive protein levels. We conclude that SDF-1αand sRAGE appear to play a major role in the diagnosis of preterm birth and its evaluation could be convenient and useful for predicting preterm birth.

Use of Petroleum Derived Spray Oils in Washington Grapevine Powdery Mildew Management Programs

2005 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
G. G. Grove ◽  
J. Lunden ◽  
S. Spayd
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Initial Treatment ◽  
Visual Detection ◽  
Titratable Acidity ◽  
Growing Season ◽  
Soluble Solids ◽  
Fungicide Treatment ◽  
Grapevine Powdery Mildew ◽  
Eastern Washington

The effects of petroleum-derived spray oils (PDSO) on powdery mildew control and selected berry characteristics were evaluated in vineyards in eastern Washington during 2001 and 2002. Up to seven PDSO applications were made during each growing season between the 15-to-30-cm shoot stage and veraison. The use of oil decreased total soluble solids (TSS) at harvest by 0.17% per application but had no significant effects on berry weight, pH, or titratable acidity. Because of their documented eradicant and antisporulant properties, PDSO were also utilized as the initial treatment in fungicide treatment sequences initiated upon the first visual detection of powdery mildew signs in the vineyard. When used in this fashion very early in powdery mildew epidemics, PDSO helped to reduce fungicide usage and input costs without compromising disease control. Accepted for publication 15 February 2005. Published 17 March 2005.

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 Grapevine powdery mildew (Erysiphe necator): a fascinating system for the study of the biology, ecology and epidemiology of an obligate biotroph

2011 ◽  
Vol 13 (1) ◽  
pp. 1-16 ◽  
Author(s):  
DAVID M. GADOURY ◽  
LANCE CADLE-DAVIDSON ◽  
WAYNE F. WILCOX ◽  
IAN B. DRY ◽  
ROBERT C. SEEM ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Erysiphe Necator ◽  
Grapevine Powdery Mildew ◽  
Obligate Biotroph
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