Fungicide Resistance Among Botrytis cinerea Isolates from California Strawberry Fields

2010 ◽  
Vol 11 (1) ◽  
pp. 12 ◽  
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.

scholarly journals First Report of Thiophanate-Methyl Resistance in Botrytis cinerea on Strawberry from South Carolina

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1700-1700 ◽  
Author(s):  
D. Fernández-Ortuño ◽  
G. Schnabel
Keyword(s):  
South Carolina ◽  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Pathogenic Fungi ◽  
Gray Mold ◽  
Resistant Isolate ◽  
Conidial Suspension ◽  
Strawberry Fruit ◽  
Single Spore ◽  
Thiophanate Methyl

Botrytis cinerea Pers.:Fr. is the causal agent of gray mold disease and one of the most important plant-pathogenic fungi affecting strawberry (Fragaria× ananassa). Control of gray mold mainly depends on fungicides, including the methyl benzimidazole carbamate (MBC) thiophanate-methyl. In 2011, strawberries with gray mold symptoms were collected from commercial fields near Chesnee, Florence, Lexington, McBee, Monetta, and North Augusta, all in South Carolina. MBC fungicides were used in most of these fields for gray mold control during the last 3 years. A total of 124 single spore B. cinerea isolates were obtained, each from a different fruit. Resistance to thiophanate-methyl (Topsin M 70WP, Cerexagri-Nisso LLC, King of Prussia, PA) was determined using a conidial germination assay as described previously (1). The majority of isolates (81.4%) were resistant; the rest were sensitive. Resistant isolates were found in all locations with some populations (Chesnee, McBee, and Lexington) revealing no sensitive isolates. Genomic DNA from 35 resistant isolates (representing all locations) and 10 sensitive isolates (from Chesnee, Monetta, and North Augusta, SC) was extracted, and the molecular basis of MBC fungicide resistance was determined as described previously (2). All MBC-resistant isolates possessed the E198A mutation known to confer high levels of MBC fungicide resistance in many fungi, including B. cinerea (2,3). Disease was assessed using a detached strawberry fruit assay. Commercially grown strawberry fruit (24 in total for each isolate and fungicide treatment) were rinsed with water, dried, and sprayed 4 h prior to inoculation with either water or 2.4 g/liter of Topsin M to runoff using a hand mister. Fruit was stab-wounded with a sterile syringe and inoculated with a 30-μl droplet of a conidial suspension (106 spores/ml) of either a sensitive or resistant isolate. After inoculation, the fruit were kept at 22°C for 4 days. The sensitive isolate developed gray mold disease in untreated but not Topsin M-treated fruit. The resistant isolate developed gray mold disease of equal severity in both, the control and fungicide-treated fruit. This experiment was repeated once. The results of the study show that resistance to MBC fungicides is common and widespread in B. cinerea from strawberry in South Carolina. Prior to this study, resistance to MBCs has only been reported in B. cinerea from ornamental crops grown in greenhouses in South Carolina (4). References: (1) J. E. Luck and M. R. Gillings. Mycol. Res. 99:1483, 1995. (2) R. W. S. Weber and M. Hahn. J. Plant Dis. Prot. 118:17, 2011. (3) O. Yarden and T. Katan. Phytopathology 83:1478, 1993. (4) L. F. Yourman and S. Jeffers. Plant Dis. 83:569, 1999.

scholarly journals Resistance to Increasing Chemical Classes of Fungicides by Virtue of “Selection by Association” in Botrytis cinerea

2016 ◽  
Vol 106 (12) ◽  
pp. 1513-1520 ◽  
Author(s):  
Meng-Jun Hu ◽  
Kerik D. Cox ◽  
Guido Schnabel
Keyword(s):  
Data Analysis ◽  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Low Risk ◽  
Single Site ◽  
Thiophanate Methyl ◽  
Specific Location ◽  
Multiple Chemical ◽  
Chemical Class ◽  
Over Time

Previous research has shown that Botrytis cinerea isolates with resistance to multiple chemical classes of fungicides exist in eastern strawberry fields. In this study, the fungicide resistance profiles of 2,130 isolates from flowers of commercial strawberry fields located in multiple states was determined over four consecutive strawberry production seasons. Producers were asked to alternate single-site fungicides that were considered low risk in their specific location based on resistance monitoring results in their fields. This recommendation led to an increase of chemical class diversity used in the spray programs. Results indicated that simultaneous resistance in individual isolates to two, three, four, five, six, and seven classes of fungicides increased over time. The increase in chemical class resistances within isolates was likely due to a process we termed “selection by association”, where fungicide resistance traits were often linked to the trait being selected rather than the selectable trait itself. Data analysis also indicated that the odds were highest for isolates resistant to one chemical class (1CCR) to be resistant to thiophanate-methyl; for 2CCR isolates to be resistant to thiophanate-methyl and pyraclostrobin; and for 3CCR isolates to be resistant to thiophanate-methyl, pyraclostrobin, and either cyprodinil or fenhexamid. We hypothesize that the more chemical classes are used in a spray program, the faster isolates will be selected with increasing numbers of chemical class resistances by virtue of selection by association if such isolates preexist in the population.

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

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.

scholarly journals First Report of Fenhexamid-Resistant Botrytis cinerea Causing Gray Mold on Heurchera in a North American Greenhouse

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 147-147 ◽  
Author(s):  
G. W. Moorman ◽  
A.-S. Walker ◽  
S. May
Keyword(s):  
Botrytis Cinerea ◽  
Mode Of Action ◽  
Gray Mold ◽  
North Central ◽  
First Report ◽  
Group I ◽  
Central Pennsylvania ◽  
Commercial Operation ◽  
Penn State ◽  
Botryotinia Fuckeliana

Greenhouse-grown Heuchera plants, treated with fenhexamid (Decree, SePRO, Carmel, IN; FRAC group 17 hydroxyanilide), with active gray mold were submitted to the Penn State Plant Disease Clinic in December 2010 from a commercial operation in north-central Pennsylvania. Genetic and phenotypic analyses identified the isolate as Botrytis cinerea Pers. (teleomorph Botryotinia fuckeliana (de Bary) Whetzel), HydR3 phenotype (2) and not B. pseudocinerea (previously Botrytis group I) (4), naturally resistant to fenhexamid (phenotype HydR1) (1). While 0.2 μg of fenhexamid per ml or less is required to slow mycelial growth and germ tube elongation of sensitive isolates by 50% (EC50), the radial growth EC50 of the Heuchera isolate was approximately 2,000 μg of fenhexamid per ml in culture. Five cucumber seedlings receiving 25 μl of 0.1 M dextrose containing the label rate of Decree (1,800 μg/ml) on the growing tip were inoculated with colonized agar in the drop. Five check plants received 25 μl of 0.1 M dextrose. B. cinerea from silica gel storage since 1988 was also tested. This experiment was repeated three times. The 1988 isolate killed all fungicide-free but no fenhexamid-treated plants. The Heuchera isolate killed all fungicide-free and fenhexamid-treated plants within 4 days. To our knowledge, this is the first report of B. cinerea from a greenhouse in North America with fenhexamid resistance. Resistance occurs in U.S. fields (3). The Heuchera isolate's HydR3 resistance phenotype (2) has been detected in Germany, Japan, and France and has mutations affecting the 3-keto reductase protein, encoded by the erg27 gene, the specific target of fenhexamid and involved in Botrytis sterol biosynthesis. The Decree label states that it is to be used only twice on a crop before switching to a different mode of action. Greenhouses have resident Botrytis populations that are likely to be exposed to any fungicide applied in the structure. Growers should consider using fenhexamid only twice in a particular greenhouse, rather than on a particular crop, before switching to a different mode of action. References: (1) P. Leroux et al. Crop Prot. 18:687, 1999.(2) P. Leroux et al. Pest Manag. Sci. 58:876, 2002. (3) Z. Ma and T. J. Michailides. Plant Dis. 89:1083, 2005. (4) A.-S. Walker et al. Phytopathology 101:1433, 2011.

scholarly journals Characterization of Botrytis cinerea From Commercial Cut Flower Roses

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1577-1583 ◽  
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.

scholarly journals Population Genetics and Fungicide Resistance of Botrytis cinerea on Vitis and Prunus spp. in California

2020 ◽  
Vol 110 (3) ◽  
pp. 694-702 ◽  
Author(s):  
Jeffery A. DeLong ◽  
Seiya Saito ◽  
Chang-Lin Xiao ◽  
Rachel P. Naegele
Keyword(s):  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Gray Mold ◽  
Broad Host Range ◽  
Multilocus Genotype ◽  
Postharvest Diseases ◽  
High Genetic Diversity ◽  
Action Committee ◽  
Vitis Sp ◽  
Prunus Spp

Botrytis cinerea, the causal agent of gray mold, has high genetic diversity and a broad host range. In Vitis sp. and Prunus spp., B. cinerea causes pre- and postharvest diseases, and fungicides are routinely applied to prevent yield loss. In total, 535 isolates of B. cinerea collected from Vitis sp. and Prunus spp. in 2012, 2016, and 2017 were genotyped using 18 microsatellite markers and the transposable elements (TEs) Boty and Flipper. Only nine of the polymorphic markers and the two TEs were considered informative and retained for the final analyses. Of the 532 isolates, 297 were tested for resistance to seven fungicides representing six Fungicide Resistance Action Committee classes. After clone correction, 295 multilocus genotype groups were retained across the 3 years in 326 individuals, and four genetic subpopulations were detected. High levels of clonality were observed across the dataset. Significant pairwise differentiation was detected among years, locations, and TE composition. However, most of the diversity observed was within a subpopulation and not among subpopulations. No genetic differentiation was detected among resistant and sensitive isolates for individual fungicide classes. When resistance to the total number of fungicides was compared, regardless of the fungicide class, significant differentiation was detected among isolates that are resistant to two fungicide classes and those resistant to three or four fungicide groups. Fungicide resistance frequencies were stable for most chemistries evaluated with the exception of fluopyram, which increased from 2012 to 2016/2017.

scholarly journals First Report of Resistance to Pyraclostrobin, Boscalid, and Thiophanate-methyl in Colletotrichum gloeosporioides from Blueberry in Georgia

2019 ◽  
Vol 20 (4) ◽  
pp. 261-262
Author(s):  
Md Emran Ali ◽  
Owen Hudson ◽  
Will H. Hemphill ◽  
Timothy B. Brenneman ◽  
Jonathan E. Oliver
Keyword(s):  
Fungicide Resistance ◽  
Colletotrichum Gloeosporioides ◽  
Single Site ◽  
Fruit Rot ◽  
Growth Inhibition Assay ◽  
Thiophanate Methyl ◽  
Real Risk ◽  
Sensitivity Tests ◽  
Southern Highbush ◽  
Succinate Dehydrogenase Inhibitor

Colletotrichum gloeosporioides causes anthracnose fruit rot and leaf spot on blueberries. For controlling anthracnose, blueberry growers mostly rely on pre- and postharvest fungicide applications in addition to orchard sanitation. Single-site fungicides including quinone outside inhibitors (QoIs), such as pyraclostrobin and azoxystrobin as well as fungicides containing the succinate dehydrogenase inhibitor (SDHI) boscalid are used frequently to control anthracnose rots and other diseases on blueberry; however, development of fungicide resistance is a real risk because a limited number of fungicides are now available for blueberry disease management. In 2019, three isolates of C. gloeosporioides were cultured from blueberry fruit collected from southern highbush blueberry cultivar ‘Farthing’ in two commercial blueberry fields in Pierce County, Georgia, where ripe rot had been a problem. Fungicide sensitivity tests were conducted using a mycelial growth inhibition assay as described previously. A total of nine fungicides were evaluated to determine the sensitivity of these C. gloeosporioides isolates. All three isolates were resistant to thiophanate-methyl, the QoI fungicide pyraclostrobin, and the SDHI fungicide boscalid. These findings suggest that continuous monitoring of fungicide resistance is necessary to avoid the unwarranted application of single-site fungicides.

Gray mold in strawberries in the Paraná state of Brazil is caused by Botrytis cinerea and its isolates exhibit multiple-fungicide resistance

2021 ◽  
Vol 140 ◽  
pp. 105415
Author(s):  
Juliana Nicolau Maia ◽  
Giovana Beger ◽  
Wagner Vicente Pereira ◽  
Louise Larissa May De Mio ◽  
Henrique da Silva Silveira Duarte
Keyword(s):  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Gray Mold

scholarly journals Resistance to Thiophanate-Methyl in Botrytis cinerea Isolates From Californian Vineyards and Pistachio and Pomegranate Orchards

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1069-1075
Author(s):  
Hervé F. Avenot ◽  
David P. Morgan ◽  
Joel Quattrini ◽  
Themis J. Michailides
Keyword(s):  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Gray Mold ◽  
Fitness Components ◽  
Thiophanate Methyl ◽  
Significant Difference ◽  
Shoot Blight ◽  
Growth Assay ◽  
Free Media ◽  
Weak Resistance

In this study, a mycelial growth assay was used to evaluate the sensitivity to thiophanate-methyl of 144 Botrytis cinerea isolates (collection A) from Californian vineyards and pistachio and pomegranate orchards. Based on the effective concentration that inhibits 50% of growth (EC50) values for mycelial growth inhibition on fungicide-amended media, 3, 28, 10, and 58% of the isolates showed sensitivity (SS; EC50 < 1 µg/ml), low resistance (LR; 1 < EC50 < 10 µg/ml), weak resistance (WR; 10 < EC50 < 50 µg/ml), and high resistance (HR; EC50 > 100 µg/ml) toward thiophanate-methyl, respectively. The LR and HR phenotypes were observed in pistachio and pomegranate orchards, even though pomegranate was not sprayed with thiophanate-methyl. Sensitivity to thiophanate-methyl of a historical collection of 257 B. cinerea isolates (collection B) isolated from pistachio orchards in 1992, 2005, and 2006 was assessed on potato dextrose agar amended with thiophanate-methyl at the discriminatory concentration of 10 µg/ml. Average percentages of thiophanate-methyl–resistant isolates were 50, 72, and 64% in the orchards in 1992, 2005, and 2006, respectively. A study of fitness components of selected thiophanate-methyl–resistant (LR, WR, and HR) and –sensitive (SS) isolates from collection A did not reveal any significant difference between them with respect to mycelial growth on fungicide-free media and pathogenicity on cultivar Crimson Seedless berries. Comparison of β-tubulin sequences from resistant and sensitive phenotypes revealed that a glutamic acid at position 198 was changed to alanine in all HR isolates and three LR isolates. The occurrence of thiophanate-methyl resistance in B. cinerea populations should be considered when designing spray programs against blossom and shoot blight of pistachio and gray mold of grape.

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

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2087-2093 ◽  
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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