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 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.

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 Sexual state of grape powdery mildew (Erysiphe necator) newly recorded for New Zealand

2014 ◽  
Vol 67 ◽  
pp. 324-324
Author(s):  
P.R. Johnston ◽  
J.A. Cooper ◽  
D. Park ◽  
P.W. Sutherland ◽  
P.N. Wood
Keyword(s):  
New Zealand ◽  
Powdery Mildew ◽  
Sexual Recombination ◽  
Group A ◽  
Sexual State ◽  
Group B ◽  
Asexual Populations ◽  
The Impact ◽  
First Time ◽  
Grape Powdery Mildew

Grape powdery mildew first reported in New Zealand in 1901 is widespread in New Zealand grape growing regions causing significant losses in some seasons In the summer of 2014 the sexual stage of this fungus was observed for the first time in New Zealand Subsequent surveys showed the sexual state as widespread in Gisborne Hawkes Bay and Marlborough Internationally two E necator populations are recognised Group A being asexual while Group B undergoes sexual recombination DNA was obtained from a sexual isolate from Hawkes Bay and from an asexual isolate from Canterbury and they matched Group B and Group A respectively Asexual populations overwinter in dormant buds and develop new infections at budbreak whereas sexual populations overwinter as cleistothecia (sexual fruiting bodies) with primary infections following ascospore release In Europe where both sexual and asexual populations are widespread overwintering through cleistothecia is considered most important for between season transmission The impact of this newly introduced powdery mildew population is as yet unknown but with the additional source of new season inoculum coupled with greater genetic diversity increasing the risk of fungicide resistance future control of the disease may become more difficult

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.

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

Chrysomyxa rhododendri (European rhododendron rust).

2021 ◽  
Author(s):  
Keyword(s):  
Invasive Species ◽  
Life Cycle ◽  
New Zealand ◽  
Rust Fungus ◽  
Ornamental Plants ◽  
Sexual Stage ◽  
The Usa ◽  
Asexual Form ◽  
The Uk ◽  
Accidental Introduction

Abstract C. rhododendri is a heteroecious rust fungus; an obligate parasite completing stages of its life cycle on different plants. Mating of haploid strains occurs on species of Picea, followed by the production of asexual aeciospores that infect Rhododendron species. Another asexual form producing urediniospores occurs on Rhododendron, followed by the production of teliospores (the sexual stage). All stages are known from Europe. The fungus was reported in 1954 on Rhododendron in the northwestern USA, but the aecial form has not been found in North America. The fungus is a Regulated Pest for the USA; it has been introduced into the UK, New Zealand and Australia. As an invasive species, this rust is damaging on species of Picea and Rhododendron. As latent infections on Rhododendron can be overlooked, accidental introduction of the rust may occur through the importation of these popular ornamental plants (Savile, 1973).

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