Multiple Fungicide Resistance in Botrytis: A Growing Problem in German Soft-Fruit Production

Weber, Roland W.S.; Entrop, Alfred-Peter

doi:10.5772/27199

Cited by 7 publications

(12 citation statements)

References 36 publications

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“…Individual farmers differ strongly in the intensity of their fungicide use, and we have obtained circumstantial evidence that MR strains are most frequent in fields which have been subjected to high fungicide spray intensities for many years (Weber, 2011; Weber and Entrop, 2011). For all strawberry and raspberry fields described here, we know from growers' records that five or more applications of Botrytis fungicides were made annually.…”

Section: Discussionmentioning

confidence: 93%

Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture

Rupp

Weber

Rieger³

et al. 2017

Front. Microbiol.

140

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Botrytis cinerea is a major plant pathogen, causing gray mold rot in a variety of cultures. Repeated fungicide applications are common but have resulted in the development of fungal populations with resistance to one or more fungicides. In this study, we have monitored fungicide resistance frequencies and the occurrence of multiple resistance in Botrytis isolates from raspberries, strawberries, grapes, stone fruits and ornamental flowers in Germany in 2010 to 2015. High frequencies of resistance to all classes of botryticides was common in all cultures, and isolates with multiple fungicide resistance represented a major part of the populations. A monitoring in a raspberry field over six seasons revealed a continuous increase in resistance frequencies and the emergence of multiresistant Botrytis strains. In a cherry orchard and a vineyard, evidence of the immigration of multiresistant strains from the outside was obtained. Inoculation experiments with fungicide-treated leaves in the laboratory and with strawberry plants cultivated in the greenhouse or outdoors revealed a nearly complete loss of fungicide efficacy against multiresistant strains. B. cinerea field strains carrying multiple resistance mutations against all classes of site-specific fungicides were found to show similar fitness as sensitive field strains under laboratory conditions, based on their vegetative growth, reproduction, stress resistance, virulence and competitiveness in mixed infection experiments. Our data indicate an alarming increase in the occurrence of multiresistance in B. cinerea populations from different cultures, which presents a major threat to the chemical control of gray mold.

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Section: Discussionmentioning

confidence: 93%

Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture

Rupp

Weber

Rieger³

et al. 2017

Front. Microbiol.

140

View full text Add to dashboard Cite

show abstract

“…Weekly applications of a single MOA or mixtures of single-site actives appear to have selected for multi-resistant B. cinerea strains in blackberry and strawberry (Li et al 2014a). Resistance to one fungicide in a multi-resistant isolate could be indirectly selected by the application of another fungicide for which resistance already exists, also known as "selection by association" theory (Hu et al 2016;Weber and Entrop 2011). In this report, the characterisation of multi-resistant isolates resistant to boscalid could be an example of this process as recent selection pressure from this fungicide is now essentially non-existent in B. cinerea populations.…”

Section: Discussionmentioning

confidence: 97%

Fungicide resistance characterised across seven modes of action inBotrytis cinereaisolated from Australian vineyards

Harper

Paton²,

Hall

et al. 2021

Preprint

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Gray mold, caused by Botrytis cinerea, is an economically important disease of grapes in Australia and across grape growing regions worldwide. Control of this disease relies heavily on canopy management and the application of single site fungicides. Fungicide application can lead to the selection of fungicide resistant B. cinerea populations, which has an adverse effect on the chemical control of the disease. Characterising the distribution and severity of resistant B. cinerea populations is needed to inform resistance management strategies. In this study, 725 isolates were sampled from 75 Australian vineyards during 2013 – 2016 and were screened against seven fungicides with different MOAs. The resistance frequencies for azoxystrobin, boscalid, fenhexamid, fludioxonil, iprodione, pyrimethanil and tebuconazole were 5, 2.8, 2.1, 6.2, 11.6, 7.7 and 2.9% respectively. Nearly half of the resistant isolates (43.7%) were resistant to more than one of the fungicides tested. The frequency of vineyards with at least one isolate simultaneously resistant to 1, 2, 3, 4 or 5 fungicides was 19.5, 7.8, 6.5, 10.4 and 2.6%. Resistance was associated with previously published genotypes in CytB (G143A), SdhB (H272R/Y), Erg27 (F412S), Mrr1 (D354Y), Bos1 (I365S, N373S + Q369P, I365S + D757N) and Pos5 (P319A, L412F). Expression analysis was used to characterise fludioxonil resistant isolates exhibiting overexpression (6.3 - 9.6-fold) of the ABC transporter encoded by AtrB (MDR1 phenotype). Novel genotypes were also described in CytB (S611N, D616G) and CytB (P357S). Resistance frequencies were lower when compared to most previously published surveys of both grape and non-grape B. cinerea resistance. Nonetheless, continued monitoring of critical chemical groups used in Australian vineyards is recommended.

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“…Weber, unpublished data). Furthermore, it is conceivable that repeated applications of a currently used fungicide might give rise to a co-selection of resistance against a fungicide no longer in use, provided that a large share of a Botrytis population harbours resistance to both compounds (Weber & Entrop 2011). This possibility could explain a striking accumulation of resistance against two such redundant fungicides (thiophanate-methyl and iprodione) in strains possessing quintuple resistance to all current fungicide classes in Northern German soft-fruit fields (Weber 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Whereas MBC fungicides and iprodione had been phased out from these crops since 1976 and 2008, respectively, the other five fungicides were in common use at the time of the survey. In searching for an explanation of such high levels of resistance, Weber & Entrop (2011) found a strong relationship between the number of blossom-time fungicide applications in individual soft-fruit fields and the frequency of resistance in Botrytis infections in the harvest of the same year. Further, these authors confirmed by forced-selection trials that resistance to a specific fungicide may accumulate in a Botrytis population within one vegetation period if this compound is repeatedly sprayed at blossom time, which is the primary infection period for Botrytis in soft fruits.…”

Section: Discussionmentioning

confidence: 99%

Fungicide resistance of Botrytis cinerea on lettuce in Northern Germany

Weber

Wichura

2013

J Plant Dis Prot

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In 2010-2012, a total of 309 isolates of Botrytis cinerea from 23 lettuce fields in Northern Germany was examined for sensitivity to seven fungicides with specific modes of action. Resistance against the frequently used compounds boscalid (45.0% of all isolates), iprodione (37.2%) and quinone-outside inhibitors (strobilurins, 56.3%) was the most common. Isolates combining resistance to two or all three of these fungicides were more frequent than those showing resistance against only one. Strains with cyprodinil (31.4%) or thiophanate-methyl (11.6%) resistance were also observed in the majority of fields. In contrast, resistance against fludioxonil (1 isolate) and fenhexamid (3 isolates) was rare. The abundance of B. cinerea strains with multiple resistance to several currently used fungicides has implications for future lettuce crop management which are discussed.Abbrevations: HR = high resistance, MBC = methyl benzimidazole carbamate, MEA = malt extract agar, MR = moderate resistance, PDA = potato dextrose agar, QoI = quinone outside inhibitor, s = reduced sensitivity, SA = sucrose agar, ss = high sensitivity, TWA = tap water agar, YEA = yeast extract agar

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Multiple Fungicide Resistance in Botrytis: A Growing Problem in German Soft-Fruit Production

Cited by 7 publications

References 36 publications

Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture

Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture

Fungicide resistance characterised across seven modes of action inBotrytis cinereaisolated from Australian vineyards

Fungicide resistance of Botrytis cinerea on lettuce in Northern Germany

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