Differences in the efficacy of carboxylic acid amide fungicides against less sensitive strains of Plasmopara viticola

2015 ◽  
Vol 72 (8) ◽  
pp. 1537-1539 ◽  
Author(s):  
Irene Maja Nanni ◽  
Alessandro Pirondi ◽  
Daniela Mancini ◽  
Gerd Stammler ◽  
Randall Gold ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Acid Amide ◽  
Plasmopara Viticola ◽  
Carboxylic Acid Amide

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 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 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

A time-course investigation of resistance to the carboxylic acid amide mandipropamid in field populations of Plasmopara viticola treated with anti-resistance strategies

2018 ◽  
Vol 74 (12) ◽  
pp. 2822-2834 ◽  
Author(s):  
Silvia L Toffolatti ◽  
Giuseppe Russo ◽  
Paola Campia ◽  
Piero A Bianco ◽  
Paolo Borsa ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Time Course ◽  
Acid Amide ◽  
Plasmopara Viticola ◽  
Carboxylic Acid Amide ◽  
Resistance Strategies

scholarly journals Mutagenesis of Phytophthora infestans for Resistance Against Carboxylic Acid Amide and Phenylamide Fungicides

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 675-683 ◽  
Author(s):  
Avia (Evgenia) Rubin ◽  
Dror Gotlieb ◽  
Ulrich Gisi ◽  
Yigal Cohen
Keyword(s):  
Carboxylic Acid ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Uv Light ◽  
Acid Amide ◽  
Late Blight Resistance ◽  
Plasmopara Viticola ◽  
Carboxylic Acid Amide ◽  
In Planta

The carboxylic acid amide (CAA) fungicides mandipropamid, dimethomorph, iprovalicarb, and the phenylamide fungicide mefenoxam (MFX, the active enantiomer of metalaxyl) are anti-oomycete fungicides effective against downy mildews and late blight. Resistance against MFX was reported in nature in several oomycetes including Phytophthora infestans and Plasmopara viticola, whereas resistance against CAAs was reported in P. viticola but not in P. infestans. In this study the mutability of P. infestans for resistance against CAAs and MFX (as a control) was explored under laboratory conditions. UV light or chemical mutagens (e.g., ethyl methan sulfonate [EMS]) were applied to sporangia, and the emergence of mutants resistant to CAAs or MFX, or with altered mating type, was followed. Many mutants resistant to CAAs developed at generation 0 after mutagenesis, but all showed erratic, instable resistance in planta, diminishing after 1 to 8 asexual infection cycles, and failed to grow on CAA-amended medium. In contrast, 19 mutants resistant to MFX were obtained: 6 with UV irradiation (in isolates 28 or 96) and 13 with EMS (in isolates 408, 409, and 410). In three experiments, a shift in mating type, from A1 to A2, was detected. To elucidate whether or not resistance to CAAs is recessive and therefore might emerge only after sexual recombination, A1 and A2 mutants were crossed and the F1 and F2 progeny isolates were tested for resistance. Offspring isolates segregated for resistance to MFX, with resistant isolates maintaining stable resistance in vitro and in planta, whereas all progeny isolates failed to show stable resistance to CAAs in planta or in vitro. The data suggest that P. infestans could be artificially mutated for resistance against MFX, but not against CAAs.

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