Detection of resistance to sterol demethylation-inhibiting (DMI) fungicides inCercospora beticola and efficacy of control of resistant and sensitive strains with flutriafol

Karaoglanidis, G. S.; Karadimos, D. A.; Ioannidis, P. M.

doi:10.1007/bf02979809

Cited by 10 publications

(9 citation statements)

References 14 publications

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“…) or ‘discriminatory monitoring concentration’ (Karaoglanidis et al. ). We do not consider the SAC to be a discriminatory concentration because the frequency distributions of relative growth data do not identify a critical sensitivity value associated with control failures.…”

Section: Discussionmentioning

confidence: 99%

“…Karaoglanidis et al. () proposed an RG value of 70% at the flutriafol discriminatory concentration of 1 mg a.i./l as a threshold for detection of Cercospora beticola resistant isolates. In our study, the frequency of RG above 70% in the untreated orchard was zero.…”

Section: Discussionmentioning

confidence: 99%

“…Different authors refer to the SAC as 'single discriminatory dose' (Smith et al 1991;K€ oller et al 1997;Henr ıquez et al 2011) or 'discriminatory monitoring concentration' (Karaoglanidis et al 2003). We do not consider the SAC to be a discriminatory concentration because the frequency distributions of relative growth data do not identify a critical sensitivity value associated with control failures.…”

Section: Sensitivity Of Venturia Inaequalis To Difenoconazolementioning

confidence: 99%

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Sensitivity of Venturia inaequalis to Trifloxystrobin and Difenoconazole in Uruguay

Mondino

Casanova

Bentancur

et al. 2014

Journal of Phytopathology

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The sensitivity of Venturia inaequalis to trifloxystrobin and difenoconazole was studied in Uruguay. Populations of V. inaequalis were collected from apple orchards with different histories of trifloxystrobin use. Sensitivity of populations to trifloxystrobin was analysed using a method for testing spore germination published by FRAC, using a discriminatory concentration of 2.0 mg a.i./l. Resistance to trifloxystrobin was widespread in the region of commercial apple production with resistance detected in all orchards examined, the incidences ranging from 3% to 95%. The highest frequencies were found in orchards with the most intensive use of Quinone outside inhibitors (Q o I) fungicides. Sensitivities of isolates of V. inaequalis to difenoconazole were assessed at five concentrations using a mycelial growth assay on isolates (33 isolates per orchard) from one non-commercial (baseline orchard) and two commercial orchards having differing histories of difenoconazole use. Populations in both commercial orchards exhibited reduced sensitivities to difenoconazole compared to the baseline orchard. Resistance factor (RF) values of 6.6 and 11.74 were measured in the orchards with moderate (up to 4 sprays per season) and intensive use (more than 5 sprays per season) of difenoconazole, respectively. A single-assessment concentration (SAC) was identified for assessing difenoconazole sensitivity of V. inaequalis isolates by fitting linear regressions between log 10 EC 50 and relative growth (RG) of the isolates at each fungicide concentration testing, and comparing the goodness-of-fit of the regression lines. Comparable results were obtained based on EC 50 values and RG values at a SAC of 0.05 mg of active ingredient per litre (a.i. per l). Populations from both commercial orchards differed from the baseline population, in that isolates with RG ≥70 were present at substantial levels in the former but absent from the latter.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Sensitivity Of Venturia Inaequalis To Difenoconazolementioning

confidence: 99%

See 1 more Smart Citation

Sensitivity of Venturia inaequalis to Trifloxystrobin and Difenoconazole in Uruguay

Mondino

Casanova

Bentancur

et al. 2014

Journal of Phytopathology

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“…The first sampling was carried out just after the appearance of the first disease symptoms on sugar beet leaves in the control treatments, in order to measure the pretreatment sensitivity of C. beticola population within the experimental field. To determine the resistance frequency to difenoconazole, 0.1 µg ml -1 was used as a discriminatory concentration, which was completely inhibitory for the difenoconazole-sensitive strains of the pathogen while allowing the growth of resistant isolates (19). In the second sampling, fungal isolates were obtained from all the plots of all the treatments.…”

Section: Methodsmentioning

confidence: 99%

“…In Greece, applications of benomyl began in 1971 with excellent results; however, within 2 years, the fungal populations developed resistance and fungicide efficacy was completely lost (11). However, sensitivity monitoring programs showed that even one spray application of benomyl had, as a consequence, a rapid selection of resistant strains (19). In Greece, after the emergence of benzimidazole resistance, the use of benomyl was discontinued.…”

mentioning

confidence: 99%

Control of Benzimidazole- and DMI-Resistant Strains of Cercospora beticola with Strobilurin Fungicides

Karaoglanidis

Bardas

2006

Plant Disease

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The control efficacy of two new strobilurin fungicides, trifloxystrobin and pyraclostrobin, against Cercospora beticola isolates resistant and sensitive to sterol demethylation-inhibiting (DMI) fungicides and benzimidazole fungicides and the effects on evolution of resistance were tested in the current study. Control efficacy of strobilurin fungicides was measured using three C. beticola isolates, one DMI-resistant (DMIR), one benzimidazole-resistant (BENR), and one of wild-type sensitivity (WCB). Both pyraclostrobin and trifloxystrobin provided satisfactory control of all the three isolates used in the study, when applied at 5 μg ml-1 and very high levels of control when applied at 10 μg ml-1. Control was independent of the isolate sensitivity to benomyl and difenoconazole. In contrast, benomyl applied at 10 μg ml-1 failed to control sufficiently the benzimidazole-resistant isolate, whereas difenoconazole applied at either 5 or 10 μg ml-1 failed to provide satisfactory control of the DMI-resistant isolate of the pathogen. The effects of strobilurin fungicide applications on the evolution of resistance to benzimidazole and DMI fungicides were tested under field conditions in a 2-year experiment (2003 to 2004). Applications of either trifloxystrobin or pyraclostrobin provided high levels of disease control during both years of the study, whereas applications of either benomyl or difenoconazole provided a moderate control efficacy. Measurements of resistance frequencies to benomyl and to difenoconazole showed that successive applications of benomyl tended to select for high frequencies of benzimidazole-resistant phenotypes, whereas successive applications of difenoconazole tended to select for high frequencies of DMI-resistant phenotypes. In contrast, applications of either trifloxystrobin or pyraclostrobin prevented an increase of benzimidazole- or DMI-resistant phenotypes compared with the plots treated with benomyl or difenoconazole, respectively, and decreased frequency of resistance compared with untreated control plots.

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Efficacy of azoxystrobin for the control of cucumber downy mildew (Pseudoperonospora cubensis) and fungicide residue analysis

et al. 2014

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Detection of resistance to sterol demethylation-inhibiting (DMI) fungicides inCercospora beticola and efficacy of control of resistant and sensitive strains with flutriafol

Cited by 10 publications

References 14 publications

Sensitivity of Venturia inaequalis to Trifloxystrobin and Difenoconazole in Uruguay

Sensitivity of Venturia inaequalis to Trifloxystrobin and Difenoconazole in Uruguay

Control of Benzimidazole- and DMI-Resistant Strains of Cercospora beticola with Strobilurin Fungicides

Efficacy of azoxystrobin for the control of cucumber downy mildew (Pseudoperonospora cubensis) and fungicide residue analysis

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