scholarly journals First Report of Carboxylic Acid Amide Fungicide Resistance in Plasmopara viticola (Grapevine Downy Mildew) in North America

2018 ◽  
Vol 19 (2) ◽  
pp. 139-139 ◽  
Author(s):  
Xuewen Feng ◽  
Anton Baudoin
Keyword(s):  
North Carolina ◽  
Carboxylic Acid ◽  
North America ◽  
Downy Mildew ◽  
Acid Amide ◽  
Plasmopara Viticola ◽  
Carboxylic Acid Amide ◽  
Grapevine Downy Mildew ◽  
Grape Downy Mildew ◽  
Caa Fungicides

This report documents the first known occurrence in North America of resistance in grape downy mildew (Plasmopara viticola) to the carboxylic acid amide (CAA) fungicides mandipropamid and dimethomorph. These fungicides (FRAC group 40) have been an important component of downy mildew management programs for the past decade. Resistant isolates were obtained at three locations in Virginia and one in North Carolina, at considerable distances from each other. Resistance was documented by bioassay and the presence of the G1105S mutation, which has been associated with CAA resistance of P. viticola in other areas. Further survey is needed to determine the geographic extent of this resistance.

scholarly journals Detection and Characterization of Carboxylic Acid Amide-Resistant Plasmopara viticola in China Using a TaqMan-MGB Real-Time PCR

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2338-2345
Author(s):  
Xiaoqing Huang ◽  
Xina Wang ◽  
Fanfang Kong ◽  
Theo van der Lee ◽  
Zhongyue Wang ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Real Time ◽  
Downy Mildew ◽  
Real Time Pcr ◽  
Fungicide Resistance ◽  
Management Strategies ◽  
Acid Amide ◽  
Plasmopara Viticola ◽  
Carboxylic Acid Amide ◽  
Caa Fungicides

Grape production is increasing globally and so are problems with downy mildew, one of the main constraints in grape production. Downy mildew on grape is caused by Plasmopara viticola, an obligate biotrophic pathogen belonging to the oomycetes. Control of the disease is usually performed by fungicide applications, of which carboxylic acid amide (CAA) fungicides represent one of the most widely used groups of fungicides. Our previous research showed that the extensive application of CAA fungicides can result in fungicide resistance and in China, CAA-resistant isolates of P. viticola were collected from the field in 2014. To monitor the distribution and spread of CAA fungicide resistance, we developed a TaqMan-minor groove binder (MGB) real-time PCR-based method designed on a functional mutation in the PvCesA3 gene that allows efficient identification of CAA fungicide resistant and sensitive genotypes. The assay was validated on 50 isolates using Sanger sequencing and fungicide bioassays and exploited in a comprehensive survey comprising 2,227 single-sporangiophore isolates from eight major grapevine regions in China. We demonstrate that CAA fungicide resistance in P. viticola is widespread in China. On average, 53.3% of the isolates were found to be resistant, but marked differences were found between locations with percentages of resistant isolates varying from 0.3 to 96.6%. Furthermore, the frequency of CAA-resistant isolates was found to be significantly correlated with the exposure to CAA fungicides (P < 0.05). We further discussed the possibilities to apply the TaqMan-MGB real-time PCR assay to assess the frequency of fungicide-resistant P. viticola isolates in each region or vineyard, which would facilitate the correct choice of fungicide for grape downy mildew and resistance management strategies.

scholarly journals Inheritance of resistance to carboxylic acid amide (CAA) fungicides in Plasmopara viticola

2007 ◽  
Vol 56 (2) ◽  
pp. 199-208 ◽  
Author(s):  
U. Gisi ◽  
M. Waldner ◽  
N. Kraus ◽  
P. H. Dubuis ◽  
H. Sierotzki
Keyword(s):  
Carboxylic Acid ◽  
Acid Amide ◽  
Plasmopara Viticola ◽  
Inheritance Of Resistance ◽  
Carboxylic Acid Amide ◽  
Caa Fungicides

scholarly journals Monitoring of a Single Point Mutation in the PvCesA3 Allele Conferring Resistance to Carboxylic Acid Amide Fungicides in Plasmopara viticola Populations In Yamanashi Prefecture, Japan

2015 ◽  
Vol 16 (2) ◽  
pp. 84-87 ◽  
Author(s):  
Yoshinao Aoki ◽  
Yumi Kawagoe ◽  
Nozomi Fujimori ◽  
Sayumi Tanaka ◽  
Shunji Suzuki
Keyword(s):  
Carboxylic Acid ◽  
Point Mutation ◽  
Fungicide Resistance ◽  
Single Point ◽  
Acid Amide ◽  
Plasmopara Viticola ◽  
Single Point Mutation ◽  
Carboxylic Acid Amide ◽  
Grapevine Downy Mildew ◽  
Quinone Outside Inhibitor

The use of the carboxylic acid amide (CAA) fungicide mandipropamid to manage grapevine downy mildew in vineyards in Japan has been increasing since 2010, because of widespread quinone outside inhibitor fungicide resistance in the Plasmopara viticola population. However, CAA fungicide resistance in P. viticola is becoming a serious problem worldwide. In 2013, we monitored for the presence of a single point mutation at codon 1105 of the cellulose synthase gene PvCesA3, which confers resistance to mandipropamid in P. viticola samples collected from four vineyards in Yamanashi prefecture in Japan. Five out of 157 samples were found to be heterozygotes, carrying both the mutated and nonmutated PvCesA3 alleles. Although CAA fungicide-resistant P. viticola isolates have not been reported yet in Japan, the emergence of heterozygous P. viticola populations indicates the potential risk of emergence of resistant homozygotes. Accepted for publication 14 March 2015. Published 1 May 2015

scholarly journals Geographic Distribution of Cryptic Species of Plasmopara viticola Causing Downy Mildew on Wild and Cultivated Grape in Eastern North America

2014 ◽  
Vol 104 (7) ◽  
pp. 692-701 ◽  
Author(s):  
Mélanie Rouxel ◽  
Pere Mestre ◽  
Anton Baudoin ◽  
Odile Carisse ◽  
Laurent Delière ◽  
...  
Keyword(s):  
North America ◽  
Cryptic Species ◽  
Downy Mildew ◽  
Geographic Distribution ◽  
Host Species ◽  
Large Scale ◽  
Plasmopara Viticola ◽  
Eastern North America ◽  
Grape Downy Mildew ◽  
Parthenocissus Quinquefolia

The putative center of origin of Plasmopara viticola, the causal agent of grape downy mildew, is eastern North America, where it has been described on several members of the family Vitaceae (e.g., Vitis spp., Parthenocissus spp., and Ampelopsis spp.). We have completed the first large-scale sampling of P. viticola isolates across a range of wild and cultivated host species distributed throughout the above region. Sequencing results of four partial genes indicated the presence of a new P. viticola species on Vitis vulpina in Virginia, adding to the four cryptic species of P. viticola recently recorded. The phylogenetic analysis also indicated that the P. viticola species found on Parthenocissus quinquefolia in North America is identical to Plasmopara muralis in Europe. The geographic distribution and host range of five pathogen species was determined through analysis of the internal transcribed spacer polymorphism of 896 isolates of P. viticola. Among three P. viticola species found on cultivated grape, one was restricted to Vitis interspecific hybrids within the northern part of eastern North America. A second species was recovered from V. vinifera and V. labrusca, and was distributed across most of the sampled region. A third species, although less abundant, was distributed across a larger geographical range, including the southern part of eastern North America. P. viticola clade aestivalis predominated (83% of isolates) in vineyards of the European winegrape V. vinifera within the sampled area, indicating that a single pathogen species may represent the primary threat to the European host species within eastern North America.

Carboxylic Acid Amide (CAA) Fungicides

2012 ◽  
pp. 807-830 ◽  
Author(s):  
Ulrich Gisi ◽  
Clemens Lamberth ◽  
Andreas Mehl ◽  
Thomas Seitz
Keyword(s):  
Carboxylic Acid ◽  
Acid Amide ◽  
Carboxylic Acid Amide ◽  
Caa Fungicides

Fungicide Sensitivity Survey of Plasmopara viticola Populations in Georgia Vineyards

2020 ◽  
Vol 21 (4) ◽  
pp. 256-261
Author(s):  
Sarah E. Campbell ◽  
Phillip M. Brannen ◽  
Harald Scherm ◽  
Marin T. Brewer
Keyword(s):  
Downy Mildew ◽  
Acid Amide ◽  
Leaf Disc ◽  
Plasmopara Viticola ◽  
Survey Period ◽  
Resistance Development ◽  
Grapevine Downy Mildew ◽  
Quinone Outside Inhibitor ◽  
History Of ◽  
Qoi Resistance

Grapevine downy mildew, caused by Plasmopara viticola, is among the most damaging diseases of grapes globally and in the viticultural regions of Georgia (U.S.A.). Although management of this disease typically involves fungicide applications, resistance development in P. viticola can render chemical management ineffective. The objective of this study was to survey fungicide sensitivities of P. viticola populations in vineyards across three regions in Georgia. Samples were collected from eight vineyards in 2017 and four in 2018 and tested phenotypically for sensitivity to quinone outside inhibitor (QoI), carboxylic acid amide (CAA), and phenylamide (PA) fungicides using leaf disc bioassays. In addition, DNA was extracted from P. viticola samples collected from 2015 through 2018 in these 12 vineyards and six others for a total of 18 vineyards sampled. All available DNA samples were tested for the presence of the known resistance-causing mutations G143A (QoI) and G1105S (CAA) using polymerase chain reaction (PCR). This study documented widespread occurrence of QoI resistance in P. viticola in Georgia, with 83.0% of isolates collected in 2017 and 2018 testing positive for QoI resistance based on bioassay and 82.9% of isolates collected from 2015 to 2018 testing positive for QoI resistance through PCR testing. In total, 94.4% (17/18) of surveyed vineyards had confirmed QoI resistance by the conclusion of the survey period. No reduced sensitivity to CAA or PA fungicides was identified. Due to widespread QoI resistance, these fungicides should not be relied upon for downy mildew management in Georgia vineyards with a long history of their use.

Resistance mechanism to carboxylic acid amide fungicides in the cucurbit downy mildew pathogen Pseudoperonospora cubensis

2011 ◽  
Vol 67 (10) ◽  
pp. 1211-1214 ◽  
Author(s):  
Mathias Blum ◽  
Maya Waldner ◽  
Gilberto Olaya ◽  
Yigal Cohen ◽  
Ulrich Gisi ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Downy Mildew ◽  
Acid Amide ◽  
Resistance Mechanism ◽  
Pseudoperonospora Cubensis ◽  
Carboxylic Acid Amide ◽  
Cucurbit Downy Mildew
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