Characterisation of the first Stemphylium vesicarium isolates resistant to strobilurins in Italian pear orchards

Alberoni, Giulia; Cavallini, Damiano; Brunelli, A.

doi:10.1007/s10658-009-9559-3

Cited by 22 publications

(7 citation statements)

References 5 publications

(9 reference statements)

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“…Alberoni et al (2008) reported the high effectiveness of QoI fungicides to control S. vesicarium brown spot of pear (of which trifloxystrobin and pyraclostrobin were used in the present study). However, the risk of resistance evolution in this group is estimated to be high according to the Fungicide Resistance Action Committee ( FRAC, 2016 ) and, after several years of treatment, S. vesicarium has already developed resistance to these fungicides ( Alberoni et al, 2010 ).…”

Section: Discussionmentioning

confidence: 99%

Stemphylium Leaf Blight of Garlic (Allium sativum) in Spain: Taxonomy and In Vitro Fungicide Response

Gálvez¹,

Gil-Serna²,

García³

et al. 2016

The Plant Pathology Journal

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The most serious aerial disease of garlic is leaf blight caused by Stemphylium spp. Geographical variation in the causal agent of this disease is indicated. Stemphylium vesicarium has been reported in Spain, whereas S. solani is the most prevalent species recorded in China. In this study, Stemphylium isolates were obtained from symptomatic garlic plants sampled from the main Spanish production areas. Sequence data for the ITS1–5.8S–ITS2 region enabled assignation of the isolates to the Pleospora herbarum complex and clearly distinguished the isolates from S. solani. Conidial morphology of the isolates corresponded to that of S. vesicarium and clearly discriminated them from S. alfalfae and S. herbarum on the basis of the size and septation pattern of mature conidia. Conidial morphology as well as conidial length, width and length:width ratio also allowed the Spanish isolates to be distinguished from S. botryosum and S. herbarum. Control of leaf blight of garlic is not well established. Few studies are available regarding the effectiveness of chemical treatments to reduce Stemphylium spp. incidence on garlic. The effectiveness of nine fungicides of different chemical groups to reduce Stemphylium mycelial growth in vitro was tested. Boscalid + pyraclostrobin (group name, succinate dehydrogenase inhibitors + quinone outside inhibitors), iprodione (dicar-boximide), and prochloraz (demethylation inhibitors) were highly effective at reducing mycelial growth in S. vesicarium with EC50 values less than 5 ppm. In general, the effectiveness of the fungicide was enhanced with increasing dosage.

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Section: Discussionmentioning

confidence: 99%

Stemphylium Leaf Blight of Garlic (Allium sativum) in Spain: Taxonomy and In Vitro Fungicide Response

Gálvez¹,

Gil-Serna²,

García³

et al. 2016

The Plant Pathology Journal

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“…As mentioned above, fungicides vary in efficacy and with disease pressure [2]. Moreover, repeated use of some types of fungicides has been restricted by the emergence of fungicide-resistant strains [46]. Thus, there is a need for the search of new strategies to control S. vesicarium.…”

Section: In Vivo Antifungal Activity Of Propolis Extracts Against Stementioning

confidence: 99%

Potential Application of Propolis Extracts to Control the Growth of Stemphylium vesicarium in “Rocha” Pear

et al. 2020

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Stemphylium vesicarium (Wallr.) E. G. Simmons is the pathogen responsible of brown spot disease in pear and has become one of the main concerns for European pear producers. In Portugal, S. vesicarium is responsible for significant yield reduction and economic losses in “Rocha” pear (Pyrus communis L. cv Rocha) production. Considering the antimicrobial potential of propolis, the high incidence of brown spot in pears and the emergence of fungicides resistance in S. vesicarium, this study aimed to evaluate the potential of Portuguese propolis as an alternative strategy to control brown spot disease in “Rocha” pear. In vitro assays showed that propolis extracts were able to inhibit up to 90% the S. vesicarium mycelial growth. In vivo assays in artificially wounded and inoculated “Rocha” pears showed that, compared to the control, the disease incidence decreased up to 25% and the lesions diameter up to 57%, in fruits treated with propolis. Moreover, propolis seems to be more efficient in reducing the disease incidence when applied after pathogen inoculation (curative assay) than when applied before pathogen inoculation (prophylactic assay). Thus, the results suggest that propolis extracts have potential to be applied as part of an integrated approach for the control of brown spot of pear.

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“…Insensitivity within the S. vesicarium populations from onion in New York to fungicides in multiple FRAC groups was detected using in vitro assays. Resistance to QoI fungicides has been reported for S. vesicarium populations from pear orchards in Italy, where a discriminate dose of 0.5 mg/ml was established, above and below which isolates were considered insensitive or sensitive, respectively (Alberoni et al 2010). In this onion study, a slightly lower discriminatory dose of 0.2 mg of a.i.…”

Section: Discussionmentioning

confidence: 82%

“…Sequencing of cytb. For 105 S. vesicarium isolates, a portion of the cytb gene reported to contain mutations associated with resistance to QoIs was amplified with primers SVCBFw-SVCBRe (Alberoni et al 2010) or KES1999 and 2000 (Graf et al 2016). For each PCR reaction, the final volume (50 ml) contained 37.84 ml of sterile type I water, 5 ml of 10× PCR buffer (New England Biolabs), 1 ml of dNTPs (10 mM), 1 ml of each primer (10 mM), 0.16 ml of 5 U/ml Taq DNA polymerase (New England Biolabs), and 4 ml of DNA.…”

Section: Methodsmentioning

confidence: 99%

Emergence of Stemphylium Leaf Blight of Onion in New York Associated With Fungicide Resistance

et al. 2019

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A complex of foliar diseases affects onion production in New York, including Botrytis leaf blight (Botrytis squamosa), purple blotch (Alternaria porri), Stemphylium leaf blight (SLB; Stemphylium vesicarium), and downy mildew (Peronospora destructor). Surveys were conducted in 2015 and 2016 to evaluate the cause of severe premature foliar dieback in New York onion fields. SLB was the most prevalent disease among fields with the greatest incidence, surpassing downy mildew, purple blotch, and Botrytis leaf blight. Sequencing of the internal transcribed spacer region of ribosomal DNA and the glyceraldedyhe-3-phosphate dehydrogenase and calmodulin genes identified S. vesicarium as the species most commonly associated with SLB. S. vesicarium was typically associated with a broad range of necrotic symptoms but, most commonly, dieback of leaf tips and asymmetric lesions that often extended over the entire leaf. Because of the intensive use of fungicides for foliar disease control in onion crops in New York, the sensitivity of S. vesicarium populations to various fungicides with site-specific modes of action was evaluated. Sensitivity of S. vesicarium isolates collected in 2016 to the quinone outside inhibitor (QoI) fungicide, azoxystrobin, was tested using a conidial germination assay. Isolates representing a broad range of QoI sensitivities were selected for sequencing of the cytochrome b gene to evaluate the presence of point mutations associated with insensitivity to azoxystrobin. The G143A mutation was detected in all 74 S. vesicarium isolates with an azoxystrobin-insensitive phenotype (effective concentrations reducing conidial germination by 50%, EC50 = 0.2 to 46.7 µg of active ingredient [a.i.]/ml) and was not detected in all 31 isolates with an azoxystrobin-sensitive phenotype (EC50 = 0.01 to 0.16 µg a.i./ml). The G143A mutation was also associated with insensitivity to another QoI fungicide, pyraclostrobin. Sensitivity to other selected fungicides commonly used in onion production in New York was evaluated using a mycelial growth assay and identified isolates with insensitivity to boscalid, cyprodinil, and pyrimethanil, but not difenoconazole. The frequency of isolates sensitive to iprodione, fluxapyroxad, and fluopyram was high (93.5 to 93.6%). This article discusses the emergence of SLB as dominant in the foliar disease complex affecting onion in New York and the complexities of management posed by resistance to fungicides with different modes of action.

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Characterisation of the first Stemphylium vesicarium isolates resistant to strobilurins in Italian pear orchards

Cited by 22 publications

References 5 publications

Stemphylium Leaf Blight of Garlic (Allium sativum) in Spain: Taxonomy and In Vitro Fungicide Response

Stemphylium Leaf Blight of Garlic (Allium sativum) in Spain: Taxonomy and In Vitro Fungicide Response

Potential Application of Propolis Extracts to Control the Growth of Stemphylium vesicarium in “Rocha” Pear

Emergence of Stemphylium Leaf Blight of Onion in New York Associated With Fungicide Resistance

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