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 Evaluation of Quinoxyfen Resistance of Erysiphe necator (Grape Powdery Mildew) in a Single Virginia Vineyard

Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2586-2591 ◽  
Author(s):  
Xuewen Feng ◽  
Mizuho Nita ◽  
Anton B. Baudoin
Keyword(s):  
United States ◽  
Powdery Mildew ◽  
Disease Control ◽  
Low Dose ◽  
Disease Incidence ◽  
The United States ◽  
Field Trials ◽  
Erysiphe Necator ◽  
Late Season ◽  
Grape Powdery Mildew

The protectant fungicide quinoxyfen has been used against grape powdery mildew (Erysiphe necator) in the United States since 2003. In 2013, isolates of grape powdery mildew with reduced quinoxyfen sensitivity (here designated as quinoxyfen lab resistance or QLR) were detected in a single vineyard in western Virginia, USA. Field trials were conducted in 2014, 2015, and 2016 at the affected vineyard to determine to what extent quinoxyfen might still contribute to disease control. Powdery mildew control by quinoxyfen was similar to, or only slightly less than, that provided by myclobutanil and boscalid in all three years. In 2016, early- versus late-season applications of quinoxyfen were compared to test the hypothesis that early-season applications were more effective, but differences were small. A treatment with two early quinoxyfen applications, at bloom and 2 weeks later, followed by a myclobutanil-boscalid plus a low dose of sulfur rotation provided slightly better control of foliar disease incidence than treatments containing four quinoxyfen applications or two midseason or two late quinoxyfen applications supplemented by myclobutanil and boscalid applications; severity differences were small and nonsignificant. Metrafenone and benzovindiflupyr generally provided excellent powdery mildew control. The frequency of QLR in vines not treated with quinoxyfen slowly declined from 65% in 2014 to 46% in 2016. Further research is needed to explain how, despite this QLR frequency, quinoxyfen applied to grapes in the field was still able to effectively control powdery mildew.

scholarly journals An initial genetic characterisation of the grape powdery mildew (Erysiphe necator) in New Zealand associated with recent reports of the sexual stage

2015 ◽  
Vol 68 ◽  
pp. 389-395 ◽  
Author(s):  
J.A. Cooper ◽  
D. Park ◽  
P.R. Johnston
Keyword(s):  
New Zealand ◽  
Powdery Mildew ◽  
Disease Incidence ◽  
Sexual Stage ◽  
Erysiphe Necator ◽  
Asexual Form ◽  
And Control ◽  
First Time ◽  
Practical Impact ◽  
Grape Powdery Mildew

The asexual form of the grape powdery mildew Erysiphe necator has been present in New Zealand for over 100 years In 2013 the sexual stage was reported for the first time in vineyards in Hawkes Bay associated with increased disease issues This paper presents an initial genetic analysis of New Zealand populations compared to known populations overseas and tentatively identifies two haplotypes new to New Zealand Initial analysis of matingtype ratios indicates only one of these haplotypes is sexually reproducing A better understanding of the fundamental character of the New Zealand populations of Erysiphe necator is needed before an accurate assessment can be made of the practical impact that the introduction of the sexual stage has had on disease incidence and control

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 Adaptive genomic structural variation in the grape powdery mildew pathogen, Erysiphe necator

BMC Genomics ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 1081 ◽  
Author(s):  
Laura Jones ◽  
Summaira Riaz ◽  
Abraham Morales-Cruz ◽  
Katherine CH Amrine ◽  
Brianna McGuire ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Structural Variation ◽  
Erysiphe Necator ◽  
Genomic Structural Variation ◽  
Powdery Mildew Pathogen ◽  
Grape Powdery Mildew

scholarly journals Differential Gene Expression During Conidiation in the Grape Powdery Mildew Pathogen, Erysiphe necator

2011 ◽  
Vol 101 (7) ◽  
pp. 839-846 ◽  
Author(s):  
Laura Wakefield ◽  
David M. Gadoury ◽  
Robert C. Seem ◽  
Michael G. Milgroom ◽  
Qi Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Powdery Mildew ◽  
Differential Gene Expression ◽  
Polymorphism Analysis ◽  
Erysiphe Necator ◽  
Powdery Mildews ◽  
Differential Gene ◽  
Powdery Mildew Pathogen ◽  
Fungal Genes ◽  
Grape Powdery Mildew

Asexual sporulation (conidiation) is coordinately regulated in the grape powdery mildew pathogen Erysiphe necator but nothing is known about its genetic regulation. We hypothesized that genes required for conidiation in other fungi would be upregulated at conidiophore initiation or full conidiation (relative to preconidiation vegetative growth and development of mature ascocarps), and that the obligate biotrophic lifestyle of E. necator would necessitate some novel gene regulation. cDNA amplified fragment length polymorphism analysis with 45 selective primer combinations produced ≈1,600 transcript-derived fragments (TDFs), of which 620 (39%) showed differential expression. TDF sequences were annotated using BLAST analysis of GenBank and of a reference transcriptome for E. necator developed by 454-FLX pyrosequencing of a normalized cDNA library. One-fourth of the differentially expressed, annotated sequences had similarity to fungal genes of unknown function. The remaining genes had annotated function in metabolism, signaling, transcription, transport, and protein fate. As expected, a portion of orthologs known in other fungi to be involved in developmental regulation was upregulated immediately prior to or during conidiation; particularly noteworthy were several genes associated with the light-dependent VeA regulatory system, G-protein signaling (Pth11 and a kelch repeat), and nuclear transport (importin-β and Ran). This work represents the first investigation into differential gene expression during morphogenesis in E. necator and identifies candidate genes and hypotheses for characterization in powdery mildews. Our results indicate that, although control of conidiation in powdery mildews may share some basic elements with established systems, there are significant points of divergence as well, perhaps due, in part, to the obligate biotrophic lifestyle of powdery mildews.

Specific Isolation of RNA from the Grape Powdery Mildew Pathogen Erysiphe necator, an Epiphytic, Obligate Parasite

2010 ◽  
Vol 158 (1) ◽  
pp. 69-71 ◽  
Author(s):  
Lance Cadle-Davidson ◽  
Laura Wakefield ◽  
Robert C. Seem ◽  
David M. Gadoury
Keyword(s):  
Powdery Mildew ◽  
Erysiphe Necator ◽  
Obligate Parasite ◽  
Powdery Mildew Pathogen ◽  
Grape Powdery Mildew

Genetic Variation and Population Structure of the Grape Powdery Mildew Fungus, Erysiphe necator, in Southern France

2005 ◽  
Vol 113 (4) ◽  
pp. 407-416 ◽  
Author(s):  
Jean-Pierre Péros ◽  
Claire Troulet ◽  
Mikaël Guerriero ◽  
Corinne Michel-Romiti ◽  
Jean-Loup Notteghem
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Powdery Mildew ◽  
Powdery Mildew Fungus ◽  
Erysiphe Necator ◽  
Southern France ◽  
Grape Powdery Mildew
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