Characterization of Resistance to Six Chemical Classes of Site-Specific Fungicides Registered for Gray Mold Control on Strawberry in Spain

Botrytis cinerea, causal agent of the gray mold disease, is one of the most economically important fungal pathogens of strawberry worldwide. In Spain, as in other parts of the world, management of gray mold control primarily involves the application of fungicides. To determine the fungicide resistance of the Spanish strawberry field population, 367 B. cinerea isolates were examined from one organic and 13 conventional strawberry fields in Huelva (Spain) in 2014 and 2015. The sensitivities of these isolates to six fungicides used for gray mold management in Spain were examined using a spore germination assay based on previously published discriminatory doses. The frequency of resistance to pyraclostrobin, boscalid, cyprodinil, fenhexamid, iprodione, and fludioxonil was 74.6, 64.8, 37.0, 23.7, 14.7, and 0.8%, respectively. The majority of isolates (35.1%) were resistant to three different fungicides classes. Within these isolates, the most prevalent resistance profile (55.8%) was resistance to pyraclostrobin, boscalid, and cyprodinil, followed by the resistance profile (30.2%) of resistance to pyraclostrobin, boscalid, and fenhexamid. One isolate collected in 2015 was resistant to all six fungicide classes. Resistance to boscalid, fenhexamid, iprodione, and pyraclostrobin was found to be caused by amino acid substitutions on target proteins, including H272R/Y in SdhB, F412I/S/V in Erg27, I365 N/S in Bos1, and G143A in Cytb, respectively. The presence of multifungicide resistance phenotypes in B. cinerea isolates from strawberry fields in Spain must be considered in the development of future resistance management practices.

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Characterization of Botrytis cinerea From Commercial Cut Flower Roses

Plant Disease ◽

10.1094/pdis-09-18-1623-re ◽

2019 ◽

Vol 103 (7) ◽

pp. 1577-1583 ◽

Cited By ~ 7

Author(s):

M. Muñoz ◽

J. E. Faust ◽

G. Schnabel

Keyword(s):

Botrytis Cinerea ◽

Fungicide Resistance ◽

Management Practices ◽

Cultural Practices ◽

Disease Incidence ◽

Resistance Management ◽

Gray Mold ◽

Economic Losses ◽

Cut Flower ◽

Aspergillus Brasiliensis

Botrytis cinerea Pers. infects cut flower roses (Rosa × hybrida L.) during greenhouse production and gray mold symptoms are often expressed in the postharvest environment, resulting in significant economic losses. Disease management is based on cultural practices and preventative chemical treatments; however, gray mold outbreaks continue to occur. Rose tissues from six commercial shipments from two greenhouses in Colombia were evaluated to determine the Botrytis species composition as well as identify other pathogens present, gray mold incidence and severity, and fungicide resistance profiles. Botrytis isolates (49 total) were grouped into six morphological phenotypes, and all were identified to be B. cinerea sensu stricto. Disease incidence was higher in the petals than in the stem, stamen, ovary, sepal, or leaf tissues. Other fungi were isolated infrequently and included Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Penicillium citrinum, Aspergillus brasiliensis, and Diplodia sp. Fungicide resistance profiles were determined using previously established discriminatory doses. Isolates resistant to thiophanate-methyl, iprodione, boscalid, and cyprodinil were found frequently in all shipments and in both greenhouses. The frequency of resistance to penthiopyrad, fenhexamid, fluopyram, isofetamid, and fludioxonil varied between shipments and greenhouses. No resistance to pydiflumetofen was observed at the discriminatory doses tested. Isolates with resistance to multiple chemical classes were commonly found. These results indicate that fungicide resistance management practices may improve preharvest and postharvest gray mold control of cut flower roses.

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Succinate dehydrogenase inhibitor (SDHI) fungicide resistance prevention strategy

New Zealand Plant Protection ◽

10.30843/nzpp.2011.64.5972 ◽

2011 ◽

Vol 64 ◽

pp. 119-124 ◽

Cited By ~ 4

Author(s):

A.H. McKay ◽

G.C. Hagerty ◽

G.B. Follas ◽

M.S. Moore ◽

M.S. Christie ◽

...

Keyword(s):

New Zealand ◽

High Risk ◽

Succinate Dehydrogenase ◽

Fungicide Resistance ◽

Fungal Pathogens ◽

Resistance Management ◽

Resistance Development ◽

Development Of Resistance ◽

Action Committee ◽

Succinate Dehydrogenase Inhibitor

Succinate dehydrogenase inhibitor (SDHI) fungicides are currently represented in New Zealand by eight active ingredients bixafen boscalid carboxin fluaxapyroxad fluopyram isopyrazam penthiopyrad and sedaxane They are either currently registered or undergoing development in New Zealand for use against a range of ascomycete and basiodiomycete pathogens in crops including cereals ryegrass seed apples pears grapes stonefruit cucurbits and kiwifruit These fungicides are considered to have medium to high risk of resistance development and resistance management is recommended by the Fungicide Resistance Action Committee (FRAC) in Europe Guidelines are presented for use of SDHI fungicides in New Zealand to help avoid or delay the development of resistance in the fungal pathogens that they target

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Fungicide resistance characterised across seven chemical classes in a Botrytis cinerea population isolated from Australian vineyards

10.1101/2021.03.31.437981 ◽

2021 ◽

Author(s):

Lincoln A. Harper ◽

Scott Paton ◽

Barbara Hall ◽

Suzanne McKay ◽

Richard P. Oliver ◽

...

Keyword(s):

Adverse Effect ◽

Botrytis Cinerea ◽

Fungicide Resistance ◽

Chemical Control ◽

Management Strategies ◽

Resistance Management ◽

Gray Mold ◽

Chemical Groups ◽

Important Disease ◽

Selection Of

AbstractGray 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), Os1 (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 Mrr1 (S611N, D616G) and Cyp51 (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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Determination of Fungicide Resistance in Botrytis cinerea from Strawberry in the Central Coast Region of California

Plant Health Progress ◽

10.1094/php-rs-15-0053 ◽

2016 ◽

Vol 17 (1) ◽

pp. 30-34 ◽

Cited By ~ 6

Author(s):

Andrew Pokorny ◽

Joseph Smilanick ◽

Chang-Lin Xiao ◽

James J. Farrar ◽

Anil Shrestha

Keyword(s):

Fungicide Resistance ◽

Resistance Management ◽

Gray Mold ◽

Central Coast ◽

Production Region ◽

Management Measures ◽

Highly Sensitive ◽

Diseased Fruit ◽

Grey Mold ◽

Coast Region

Grey mold, caused by Botryis cinerea, is one of the most important diseases of strawberry in California. Management of grey mold typically relies on repeated fungicide applications. The occurrence of fungicide resistance in B. cinerea was examined in the Central Coast strawberry production region of California. In mid-May 2013, 59 samples consisting of a single diseased fruit or plant part with gray mold symptoms were collected from six different strawberry fields. Single hyphal tip cultures were then used for mycelial growth assays to compare sensitivities to four different fungicides—boscalid, fenhexamid, iprodione, and pyraclostrobin. Each isolate was tested against discriminatory doses of each of the fungicides. In addition, representative highly sensitive and highly resistant isolates were tested against a range of fungicide concentrations to determine EC50 values. Although all of the 59 isolates were sensitive to iprodione, 37%, 31%, and 29% of the isolates were resistant to pyraclostrobin, fenhexamid, and boscalid, respectively. In some instances the isolates were dual and triple-resistant to these fungicides. EC50 values were often higher than 100 mg/liter, which was the highest concentration used. Therefore, appropriate fungicide resistance management measures should be employed in strawberry growing areas of the Central Coast region of California. Accepted for publication 19 February 2016. Published 2 March 2016.

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Fungicide Resistance Profiling in Botrytis cinerea Populations from Blueberry in California and Washington and Their Impact on Control of Gray Mold

Plant Disease ◽

10.1094/pdis-02-16-0229-re ◽

2016 ◽

Vol 100 (10) ◽

pp. 2087-2093 ◽

Cited By ~ 25

Author(s):

S. Saito ◽

T. J. Michailides ◽

C. L. Xiao

Keyword(s):

Botrytis Cinerea ◽

Fungicide Resistance ◽

Resistance Management ◽

Central Valley ◽

Gray Mold ◽

Postharvest Disease ◽

Quinone Outside Inhibitor ◽

Development Of Resistance ◽

Western Washington ◽

Moderately Resistant

Gray mold caused by Botrytis cinerea is a major postharvest disease of blueberry grown in the Central Valley of California and western Washington State. Sensitivities to boscalid, cyprodinil, fenhexamid, fludioxonil, and pyraclostrobin, representing five different fungicide classes, were examined for 249 (California) and 106 (Washington) B. cinerea isolates recovered from decayed blueberry fruit or flowers. In California and Washington, 7 and 17 fungicide-resistant phenotypes, respectively, were detected: 66 and 49% of the isolates were resistant to boscalid, 20 and 29% were moderately resistant to cyprodinil, 29 and 29% were resistant to fenhexamid, and 66 and 55% were resistant to pyraclostrobin. All isolates from California were sensitive to fludioxonil, whereas 70% of the isolates from Washington showed reduced sensitivity to fludioxonil. In California, 26 and 30% of the isolates were resistant to two and three classes of fungicides, respectively. In Washington, 31, 14, 16, and 9% of the isolates were resistant to two, three, four, and five classes of fungicides, respectively. Inherent risk of the development of resistance to quinone outside inhibitor (QoI) fungicides was assessed by detecting the presence of the Bcbi-143/144 intron in gene cytb. The intron was detected in 11.8 and 40% of the isolates in California and Washington, respectively, suggesting that the risk of QoI resistance is higher in California than in Washington. On detached blueberry fruit inoculated with 11 isolates exhibiting different fungicide-resistant phenotypes, most fungicides failed to control gray mold on fruit inoculated with the respective resistant phenotypes but the mixture of cyprodinil and fludioxonil was effective against all fungicide-resistant phenotypes tested. Our findings would be useful in designing and implementing fungicide resistance management spray programs for control of gray mold in blueberry.

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Resistance to the SDHI Fungicides Boscalid, Fluopyram, Fluxapyroxad, and Penthiopyrad in Botrytis cinerea from Commercial Strawberry Fields in Spain

Plant Disease ◽

10.1094/pdis-01-17-0067-re ◽

2017 ◽

Vol 101 (7) ◽

pp. 1306-1313 ◽

Cited By ~ 23

Author(s):

Dolores Fernández-Ortuño ◽

Alejandro Pérez-García ◽

Manuel Chamorro ◽

Eduardo de la Peña ◽

Antonio de Vicente ◽

...

Keyword(s):

Amino Acid ◽

Botrytis Cinerea ◽

Fungicide Resistance ◽

Mycelial Growth ◽

Growing Season ◽

Gray Mold ◽

Effective Concentration ◽

Site Specific ◽

Resistance Patterns ◽

Succinate Dehydrogenase Inhibitors

Gray mold, caused by the necrotrophic fungus Botrytis cinerea., is one of the most economically important diseases of strawberry. Gray mold control involves the application of fungicides throughout the strawberry growing season; however, B. cinerea isolates resistant to multiple classes of site-specific fungicides have been recently reported in the Spanish gray mold population. Succinate dehydrogenase inhibitors (SDHI) constitute a relatively novel class of fungicides registered for gray mold control representing new alternatives for strawberry growers. In the present study, 37 B. cinerea isolates previously characterized for their sensitivity to boscalid and amino acid changes in the SdhB protein were used to determine the effective concentration that reduces mycelial growth by 50% (EC50) to fluopyram, fluxapyroxad, and penthiopyrad. The present study was also conducted to obtain discriminatory doses to monitor SDHI fungicide resistance in 580 B. cinerea isolates collected from 27 commercial fields in Spain during 2014, 2015, and 2016. The EC50 values ranged from 0.01 to >100 μg/ml for fluopyram, <0.01 to 4.19 μg/ml for fluxapyroxad, and, finally, <0.01 to 59.65 μg/ml for penthiopyrad. Based on these results, as well as findings from a previous publication, the discriminatory doses chosen to examine sensitivities to boscalid, fluopyram, fluxapyroxad, and penthiopyrad were 100, 15, 1, and 6 μg/ml, respectively. Over the course of the 3-year monitoring period, the overall frequencies of resistance to the four SDHI were 56.9, 6.9, 12.9, and 24.6%, respectively. The frequency of boscalid-resistant isolates decreased from 73 to 41% over the years; however, the fluopyram-resistant isolates increased from 5 to 10% after 1 year of registration. Four SDHI resistance patterns were observed in our population, which included patterns I (30%; resistance to boscalid), II (13.8%; resistance to boscalid and penthiopyrad), III (5.7%; boscalid, fluxapyroxad, and penthiopyrad), and IV (7.9%; resistance to boscalid, fluopyram, fluxapyroxad, and penthiopyrad). Patterns I and II were associated with the amino acid substitutions H272R and H272Y; pattern III was associated only with the H272Y mutation; and, finally, pattern IV was associated with the N230I allele in the SdhB subunit. For gray mold management, it is suggested that the simultaneous use of boscalid and penthiopyrad should be limited to one application per season; however, fluxapyroxad and, especially, fluopyram could be used as valid SDHI alternatives for gray mold control, although they should be applied with caution.

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Characterization of the Field Fludioxonil Resistance and Its Molecular Basis in Botrytis cinerea from Shanghai Province in China

Microorganisms ◽

10.3390/microorganisms9020266 ◽

2021 ◽

Vol 9 (2) ◽

pp. 266

Author(s):

Weizhen Wang ◽

Yuan Fang ◽

Muhammad Imran ◽

Zhihong Hu ◽

Sicong Zhang ◽

...

Keyword(s):

Amino Acid ◽

Botrytis Cinerea ◽

Fungicide Resistance ◽

Molecular Basis ◽

Resistance Mechanisms ◽

Gray Mold ◽

Amino Acid Sequences ◽

Necrotrophic Pathogen ◽

Moderate Resistance

Botrytis cinerea is a destructive necrotrophic pathogen that can infect many plant species. The control of gray mold mainly relies on the application of fungicides, and the fungicide fludioxonil is widely used in China. However, the field fungicide resistance of B. cinerea to this compound is largely unknown. In this study, B. cinerea isolates were collected from different districts of Shanghai province in 2015–2017, and their sensitivity to fludioxonil was determined. A total of 65 out of 187 field isolates (34.76%) were found to be resistant to fludioxonil, with 36 (19.25%) showing high resistance and 29 (15.51%) showing moderate resistance. Most of these resistant isolates also showed resistance to iprodione, and some developed resistance to fungicides of other modes of action. AtrB gene expression, an indicator of MDR1 and MDR1h phenotypes, was not dramatically increased in the tested resistant isolates. Biological characteristics and osmotic sensitivity investigations showed that the fitness of resistant isolates was lower than that of sensitive ones. To investigate the molecular resistance mechanisms of B. cinerea to fludioxonil, the Bos1 amino acid sequences were compared between resistant and sensitive isolates. Resistant isolates revealed either no amino acid variations or the mutations I365S, I365N, Q369P/N373S, and N373S.

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Isolation and molecular characterization of ginger soft rot pathogenic fungi in Aizawl district of Mizoram, India

Science Vision ◽

10.33493/scivis.18.04.02 ◽

2018 ◽

Vol 18 (4) ◽

pp. 111-119

Author(s):

G. Rosangkima ◽

Vanramliana ◽

H. Lalthanzara ◽

Lalringngheti ◽

H.C. Lalramnghaki

Keyword(s):

Fungal Pathogens ◽

Pathogenic Fungi ◽

Soft Rot ◽

Management Programme ◽

Fusarium Spp ◽

Soft Rot Disease ◽

The World ◽

Causative Agents ◽

Rot Disease

Ginger soft rot disease caused by fungal pathogens have become one of the most serious problems causing reduced production around the world. It has also caused a major problem among farmers of Mizoram state in India resulting in a huge decline in rhizome yield. However, the exact causative agents of this disease have not been identified in the state. Therefore, the present study was undertaken to isolate and characterized the causative agents of ginger soft rot disease from the diseased plants collected from five different villages of Aizawl district, Mizoram. Isolated fungi were cultured and morphological and molecular identification were done using internal transcribed spacer of rDNA. Fusarium oxysporum, F. solani and Plectosphaerella cucumerina were identified in ginger samples from five villages. Fusarium spp. were the most common and seem to be the major causative agents. It is suggested that further investigation is required to explore the diversity of ginger soft rot pathogenic fungi in the whole state which could be helpful in introducing effective and eco-friendly disease management programme.

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Genome sequence of Venturia carpophila, the causal agent of peach scab

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-11-20-0321-a ◽

2021 ◽

Author(s):

Yang Zhou ◽

Lei Zhang ◽

Fei Fan ◽

Zuo-Qian Wang ◽

Yue Huang ◽

...

Keyword(s):

Genome Sequence ◽

Fungicide Resistance ◽

Causal Agent ◽

Whole Genome Sequence ◽

Single Spore ◽

Host Interaction ◽

Fungal Biology ◽

The World ◽

High Quality Genome

Venturia carpophila, the causal agent of scab disease on peach, is a host-specific fungus which is widely distributed around the world including China. In our previous study, samples were collected from 14 provinces in China and 750 isolates were obtained by single spore separation. Here, we reported the first highly contiguous whole-genome sequence (35.87 Mb) of the V. carpophila isolate ZJHZ1-1-1, which included 33 contigs with N50 value of 2.01 Mb and maximum contig length of 3.39 Mb. The high-quality genome sequence and annotation resource will be useful to study the fungal biology, pathogen-host interaction, fungicide resistance, characterization of important genes, population genetic diversity and development of molecular markers for genotyping and species identification.

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Within-Season Shift in Fungicide Resistance Profiles of Botrytis cinerea in California Strawberry Fields

Plant Disease ◽

10.1094/pdis-03-18-0406-re ◽

2019 ◽

Vol 103 (1) ◽

pp. 59-64 ◽

Cited By ~ 8

Author(s):

Scott D. Cosseboom ◽

Kelly L. Ivors ◽

Guido Schnabel ◽

Patricia K. Bryson ◽

Gerald J. Holmes

Keyword(s):

Botrytis Cinerea ◽

Fungicide Resistance ◽

Mycelial Growth ◽

Target Genes ◽

Resistance Management ◽

Gray Mold ◽

Field Resistance ◽

Early Season ◽

Late Season ◽

Growth Assay

Sensitivity of Botrytis cinerea to seven fungicide chemical classes was determined for 888 isolates collected in 2016 from 47 California strawberry fields. Isolates were collected early season (minimum fungicide exposure) and late season (maximum fungicide exposure) from the same planting block in each field. Resistance was determined using a mycelial growth assay, and variable frequencies of resistance were observed to each fungicide at both sampling times (early season %, late season %): boscalid (12, 35), cyprodinil (12, 46), fenhexamid (53, 91), fludioxonil (1, 4), fluopyram (2, 7), iprodione (25, 8), isofetamid (0, 1), penthiopyrad (8, 25), pyraclostrobin (77, 98), and thiophanate-methyl (81, 96). Analysis of number of chemical class resistances (CCRs) revealed an increasing shift in CCR from the early to late season. Phenotypes of 40 isolates that were resistant or sensitive to different chemical classes were associated with presence or absence of mutations in target genes. Fungicide-resistance phenotypes determined in the mycelial growth assay closely matched (93.8%) the genotype observed. Previously described resistance-conferring mutations were found for each gene. A survey of fungicide use from 32 of the sampled fields revealed an average of 15 applications of gray mold–labeled fungicides per season at an average interval of 12 days. The most frequently applied fungicides (average number of applications during the 2016 season) were captan (7.3), pyraclostrobin (2.5), cyprodinil (2.3), fludioxonil (2.3), boscalid (1.8), and fenhexamid (1.4). Multifungicide resistance is widespread in California. Resistance management tactics that reduce selection pressure by limiting fungicide use, rotating among Fungicide Resistance Action Committee codes, and mixing/rotating site-specific fungicides with multisite fungicides need to be improved and implemented.

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