Sensitivity of Cercospora beticola to fungicides in Slovakia

The fungus Cercospora beticola Sacc. is the one of the most important pathogens on the sugar beet. The frequent application of fungicides with the same mode of action increase a risk of development of resistant strains of the pathogen. Occurrence of C. beticola resistant strains has been never researched in Slovakia. In this work, C. beticola isolates were collected from 10 localities of Slovakia and analysed for fungicide resistance in laboratory conditions. Nine fungicides with different mode of action were tested – trifloxystrobin + cyproconazole, kresoxim-methyl + epoxiconazole, azoxystrobin + cyproconazole, thiophanate-methyl + tetraconazole, thiophanate-methyl, prochloraz + propiconazole, picoxystrobin, tetraconazole, and difenoconazole. The results confirmed, that occurrence of fungicide resistance in C. beticola population was established in Slovakia. Different criteria of assessment of fungicide resistance (based on EC50 and on growth rate – inhibition percentage) showed slightly different results, but both criteria confirmed resistant C. beticola strains to thiophanate-methyl, picoxystrobin and difenoconazole. Fields with higher frequency of application of these fungicides significantly supported the development of resistant strains. Assessment of any C. beticola strains have not confirmed reduced sensitivity to active ingredients tetraconazole and prochloraz + propiconazole. The lowest level of risk of fungicide resistance was confirmed in the locality Oslany. It is very important to focus on anti-resistant strategy and reduce of using fungicides on localities, where the occurrence of resistant C. beticola strains was confirmed – Dolné Saliby (thiophanate-methyl and picoxystrobin) and Senec (picoxystrobin and difenoconazole).

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Cercospora beticola Strains from Sugar Beet Tolerant to Triphenyltin Hydroxide and Resistant to Thiophanate Methyl

Plant Disease ◽

10.1094/pd-80-0103b ◽

1996 ◽

Cited By ~ 12

Keyword(s):

Sugar Beet ◽

Cercospora Beticola ◽

Thiophanate Methyl

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Sensitivity of Botrytis cinerea from Connecticut Greenhouses to Benzimidazole and Dicarboximide Fungicides

Plant Disease ◽

10.1094/pdis.1997.81.7.729 ◽

1997 ◽

Vol 81 (7) ◽

pp. 729-732 ◽

Cited By ~ 46

Author(s):

J. A. LaMondia ◽

S. M. Douglas

Keyword(s):

Growth Rate ◽

Botrytis Cinerea ◽

Fungicide Resistance ◽

Fungicide Sensitivity ◽

Thiophanate Methyl ◽

Dicarboximide Resistance

Botrytis cinerea was isolated from infected plants in six greenhouses in Connecticut. Forty-five isolates were evaluated in vitro to determine fungicide sensitivity to benzimidazole (benomyl and thiophanate-methyl) and dicarboximide fungicides (vinclozolin and iprodione). B. cinerea isolates with fungicide resistance were recovered from each greenhouse sampled. Benzimida-zole resistance was more common than dicarboximide resistance (74 to 76% versus 36 to 43%, respectively). Multiple fungicide resistance was common. Nineteen isolates were resistant to both a benzimidazole and a dicarboximide fungicide. The level (EC50) of resistance to dicer-boximides was low compared with resistance to benzimidazoles. Isolate growth rate was not correlated to fungicide sensitivity or EC50. Fungicide resistance was apparently unrelated to the patterns of fungicide use in greenhouses sampled.

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Fungicide Resistance Among Botrytis cinerea Isolates from California Strawberry Fields

Plant Health Progress ◽

10.1094/php-2010-0806-01-rs ◽

2010 ◽

Vol 11 (1) ◽

pp. 12 ◽

Cited By ~ 6

Author(s):

Julien Mercier ◽

Mansun Kong ◽

Fred Cook

Keyword(s):

Botrytis Cinerea ◽

Mode Of Action ◽

Fungicide Resistance ◽

Gray Mold ◽

Single Site ◽

Widespread Occurrence ◽

Thiophanate Methyl ◽

Inhibition Zones ◽

Agar Diffusion Assay ◽

Diffusion Assay

The resistance to four fungicides used for the management of Botrytis rot (gray mold) in strawberry was evaluated among 65 isolates of Botrytis cinerea from coastal California. Fungicide resistance was tested by agar diffusion assay on Czapek-Dox agar. Isolates not showing inhibition zones around wells at a discriminatory concentration were considered resistant. Concentrations of active ingredients for detecting resistance were 50 mg a.i./liter for thiophanate-methyl, 10 mg a.i./liter for fenhexamid, 50 mg a.i./liter for cyprodinil and fludioxonil (Switch pre-mix), and 100 mg a.i./liter for boscalid and pyraclostrobin (Pristine pre-mix). Most isolates (92%) in all fields surveyed were resistant to thiophanatemethyl. Resistance to the more recent products was also widespread and occurred in most fields. Overall, incidence of resistance among isolates was 25% for fenhexamid, 28% for cyprodinil/fludioxonil, and 66% for bocalid/pyraclostrobin. Resistant isolates remained uninhibited by higher concentrations, suggesting that they had become insensitive to these products when re-tested at twice and four times the discriminatory concentration. Among isolates of B. cinerea,85% were resistant to at least two products. This widespread occurrence of resistance to single site mode of action fungicides suggests that their effectiveness to control Botrytis rot might become impaired. Accepted for publication 21 June 2010. Published 6 August 2010.

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Fungicide Resistance Action Committee's (FRAC) Classification Scheme of Fungicides According to Mode of Action

EDIS ◽

10.32473/edis-pi131-2009 ◽

2009 ◽

Vol 2009 (2) ◽

Author(s):

Frederick M. Fishel

Keyword(s):

Mode Of Action ◽

Fungicide Resistance ◽

Classification Scheme ◽

Active Ingredients ◽

Modes Of Action ◽

Trade Names ◽

Cross Reference

Revised! PI-94, a 9-page guide by Frederick M. Fishel, addresses resistance to pesticides and describes the Fungicide Resistance Action Committee’s (FRAC) classification of fungicides and bactericides registered for use in Florida by their modes of action. A cross reference of common names for active ingredients — with corresponding examples of their trade names — is also provided. Includes sources of additional sources. Published by the UF Department of Agronomy, January 2009. PI94/PI131: Fungicide Resistance Action Committee's (FRAC) Classification Scheme of Fungicides According to Mode of Action (ufl.edu)

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Monitoring Fungicide Sensitivity of Cercospora beticola of Sugar Beet for Disease Management Decisions

Plant Disease ◽

10.1094/pdis-07-09-0471 ◽

2010 ◽

Vol 94 (11) ◽

pp. 1272-1282 ◽

Cited By ~ 48

Author(s):

Gary A. Secor ◽

Viviana V. Rivera ◽

M. F. R. Khan ◽

Neil C. Gudmestad

Keyword(s):

United States ◽

Disease Management ◽

Sugar Beet ◽

Leaf Spot ◽

Fungicide Resistance ◽

The United States ◽

Economic Damage ◽

Cercospora Beticola ◽

Cercospora Leaf Spot ◽

Cooperative Effort

Cercospora leaf spot, caused by the fungus Cercospora beticola Sacc., is the most serious and important foliar disease of sugar beet (Beta vulgaris L.) wherever it is grown worldwide. Cercospora leaf spot first caused economic damage in North Dakota and Minnesota in 1980, and the disease is now endemic. This is the largest production area for sugar beet in the United States, producing 5.5 to 6.0 million metric tons on approximately 300,000 ha, which is 56% of the sugar beet production in the United States. This Plant Disease feature article details a cooperative effort among the participants in the sugar beet industry in this growing area and represents a successful collaboration and team effort to confront and change a fungicide resistance crisis to a fungicide success program. As a case study of success for managing fungicide resistance, it will serve as an example to other pathogen–fungicide systems and provide inspiration and ideas for long-term disease management by fungicides.

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Rapid Detection of Cercospora beticola in Sugar Beet and Mutations Associated with Fungicide Resistance Using LAMP or Probe-Based qPCR

Plant Disease ◽

10.1094/pdis-09-19-2023-re ◽

2020 ◽

Vol 104 (6) ◽

pp. 1654-1661 ◽

Cited By ~ 3

Author(s):

Subidhya Shrestha ◽

Jonathan Neubauer ◽

Rebecca Spanner ◽

Mari Natwick ◽

Joshua Rios ◽

...

Keyword(s):

Sugar Beet ◽

Fungicide Resistance ◽

Rapid Detection ◽

Lamp Assay ◽

Qpcr Assay ◽

Cercospora Beticola ◽

Lamp Method ◽

In Planta ◽

Cercospora Leaf Spot

Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is the most destructive disease of sugar beet worldwide. Although growing CLS-tolerant varieties is helpful, disease management currently requires timely application of fungicides. However, overreliance on fungicides has led to the emergence of fungicide resistance in many C. beticola populations, resulting in multiple epidemics in recent years. Therefore, this study focused on developing a fungicide resistance detection “toolbox” for early detection of C. beticola in sugar beet leaves and mutations associated with different fungicides in the pathogen population. A loop-mediated isothermal amplification (LAMP) method was developed for rapid detection of C. beticola in infected sugar beet leaves. The LAMP primers specific to C. beticola (Cb-LAMP) assay was able to detect C. beticola in inoculated sugar beet leaves as early as 1 day postinoculation. A quinone outside inhibitor (QoI)-LAMP assay was also developed to detect the G143A mutation in cytochrome b associated with QoI resistance in C. beticola. The assay detected the mutation in C. beticola both in vitro and in planta with 100% accuracy. We also developed a probe-based quantitative PCR (qPCR) assay for detecting an E198A mutation in β-tubulin associated with benzimidazole resistance and a probe-based qPCR assay for detection of mutations in cytochrome P450-dependent sterol 14α-demethylase (Cyp51) associated with resistance to sterol demethylation inhibitor fungicides. The primers and probes used in the assay were highly efficient and precise in differentiating the corresponding fungicide-resistant mutants from sensitive wild-type isolates.

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Occurrence of Kasugamycin-resistant strains of Cercospora beticola in sugar beet.

Japanese Journal of Phytopathology ◽

10.3186/jjphytopath.50.637 ◽

1984 ◽

Vol 50 (5) ◽

pp. 637-640 ◽

Cited By ~ 1

Author(s):

Yoshiaki CHIKUO ◽

Toshiya SUGIMOTO ◽

Katsuichi KANZAWA ◽

Hirokatsu UCHINO

Keyword(s):

Sugar Beet ◽

Cercospora Beticola ◽

Resistant Strains

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Storage of primed pelleted sugar beet seed with minimal loss of seed vigour and active ingredients

Sugar Industry ◽

10.36961/si20315 ◽

2019 ◽

pp. 89-92

Author(s):

Martijn van Overveld ◽

Martijn Leijdekkers ◽

Noud van Swaaij

Keyword(s):

Sugar Beet ◽

Storage Temperature ◽

Seed Storage ◽

Cold Test ◽

Test Plant ◽

Active Ingredients ◽

Seed Vigour ◽

Plastic Bag ◽

Commercial Sugar ◽

Storage Methods

Different seed storage methods, varying in storage temperature, moisture and/or oxygen content, were applied to commercial sugar beet seed lots from four breeding companies. After storage for 10–11 months, germination of the seed was tested in the laboratory (cold test, 10°C). In addition, the contents of active ingredients (fungicides and insecticide) were analyzed and compared with the initial contents before storage. Based on these results, a selection of the most promising storage methods was made to test plant emergence in a field experiment. This research was performed in 2015/16 and in 2016/17. In both years, two storage treatments outperformed the others: these were storage in a closed jar with the addition of moisture absorber (i.e. silica gel) at room temperature and storage at –18°C in a closed plastic bag. Using these two storage methods, seed vigour and contents of active ingredients were comparable to those in seed that had not been stored for one year. Based on the results from this study, the advice to growers for a successful storage of residual sugar beet seed was adjusted in 2017, after including some practical guidelines and considerations.

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