scholarly journals Influence of selected fungicides registered in the Czech Republic for winter oilseed rape on in vitro Sclerotinia sclerotiorum mycelial growth

2018 ◽  
Vol 54 (No. 2) ◽  
pp. 101-110 ◽  
Author(s):  
Poslušná Jana ◽  
Plachká Eva ◽  
Mazáková Jana
Keyword(s):  
Czech Republic ◽  
Oilseed Rape ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Winter Oilseed Rape ◽  
Baseline Sensitivity ◽  
The Czech Republic ◽  
Dose Rates ◽  
The Mean

The baseline sensitivity of 55 isolates of Sclerotinia sclerotiorum, collected from oilseed rape in 6 regions of the Czech Republic, to selected fungicides was determined during the period 2013–2015. One single-component fungicide – Horizon (tebuconazole), and four multicomponent fungicides – Pictor (boscalid, dimoxystrobin), Efilor (boscalid, metconazole), Prosaro 250 EC (prothioconazole, tebuconazole), and Propulse (fluopyram, prothioconazole), were chosen as these are commonly used locally. The effect of each fungicide on the in vitro pathogen radial mycelial growth and EC<sub>50 </sub>values for the respective fungicides were determined. The following MIC values were estimated; for the fungicides Horizon 250 EW, Efilor, and Propulse the mean MIC values ranged between 0.125 and 0.250 µl/ml, for Prosaro 250 EC ranged between 0.0625 and 0.125 µl/ml, and for Pictor ranged from 0.00781 to 0.01562 µl/ml. No strains of S. sclerotiorum resistant to the tested fungicides were detected and the growth of all isolates was fully inhibited at concentrations corresponding to their registered dose rates. The highest fungicidal efficacy on the collected S. sclerotiorum isolates was recorded for Pictor, followed by Prosaro 250 with an EC<sub>50</sub> value 0.05856 µl/ml and then the remaining fungicides Propulse, Efilor, and Horizon 250 EW (EC<sub>50</sub> values 0.07277, 0.07221, and 0.08519 µl/ml, respectively).

scholarly journals Resistance behaviour of Septoria tritici to some fungicides in the territory of the Czech Republic

2012 ◽  
Vol 58 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Ludvik Tvaružek ◽  
P. Horáková ◽  
L. Ji
Keyword(s):  
Czech Republic ◽  
Septoria Tritici ◽  
Resistance Development ◽  
The Czech Republic ◽  
Colony Diameter ◽  
Dmi Fungicides ◽  
The Mean ◽  
Different Parts ◽  
Pathogen Strains

Reduction of colony diameter using two DMI-fungicides and one strobilurine fungicide was evaluated in the <i>Septoria tritici</i> population. In an <i>in vitro</i> assay, 57 strains of <i>S. tritici</i> originating from different parts of the Czech Republic were grown on agar plates containing different concentrations of fungicides. The mean EC<sub>50</sub> values of strains were analysed for flusilazole (Capitain), metconazole (Caramba) and one strobilurine fungicide: azoxystrobin (Amistar). ED 50 values for metconazole were low. There were highly significant correlation in reaction of pathogen strains to metconazole and flusilazole. Some isolates showed significant higher level of resistance to azoxystrobin. The data will be used in a continuing survey of resistance development in the <i>S. tritici</i> population originating from the territory of the Czech Republic.

scholarly journals Baseline Sensitivity of Guignardia citricarpa Isolates from Florida to Azoxystrobin and Pyraclostrobin

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 780-789 ◽  
Author(s):  
Martha Hincapie ◽  
Nan-Yi Wang ◽  
Natalia A. Peres ◽  
Megan M. Dewdney
Keyword(s):  
Mycelial Growth ◽  
Control Measure ◽  
Black Spot ◽  
Conidial Germination ◽  
Baseline Sensitivity ◽  
Qoi Fungicides ◽  
Resistance Risk ◽  
Guignardia Citricarpa ◽  
The Mean

Citrus black spot (CBS), caused by Guignardia citricarpa, is an emerging disease in Florida. Fungicide applications are the main control measure worldwide. The in vitro activity and baseline sensitivity of G. citricarpa isolates to quinone outside inhibitor (QoI) fungicides (azoxystrobin and pyraclostrobin) were evaluated. The effective concentration needed to reduce mycelial growth or spore germination by 50% (EC50) was determined for 86 isolates obtained from Florida counties where CBS is found. The effect of salicylhydroxamic acid (SHAM) plus azoxystrobin and pyraclostrobin was also assessed for mycelial growth and conidial germination. The mean EC50 for mycelial growth for azoxystrobin was 0.027 μg/ml and that for pyraclostrobin was significantly lower at 0.007 μg/ml (P < 0.0001). Similarly, the mean EC50 for conidial germination for azoxystrobin was 0.016 μg/ml and that for pyraclostrobin was significantly lower at 0.008 μg/ml (P < 0.0001). There was no effect of SHAM on inhibition of mycelial growth or conidial germination by the QoI fungicides but SHAM slightly affected mycelium inhibition by pyraclostrobin. Cytochrome b was partially sequenced and three group 1 introns were found. One intron was immediately post G143, likely inhibiting resistance-conferring mutations at that site. It is surmised that the QoI resistance risk is low in the Florida G. citricarpa population.

scholarly journals Baseline Sensitivity and Control Efficacy of Various Group of Fungicides against Sclerotinia sclerotiorum in Oilseed Rape Cultivation

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1758
Author(s):  
Nazanin Zamani-Noor
Keyword(s):  
Oilseed Rape ◽  
Sclerotinia Sclerotiorum ◽  
Fungicidal Activity ◽  
Management Strategies ◽  
Sclerotinia Stem Rot ◽  
Baseline Sensitivity ◽  
Cultural Management ◽  
Significant Yield ◽  
And Control

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum, is a devastating disease of oilseed rape that may cause significant yield losses if not controlled by cultural management strategies and fungicide applications. Studies were conducted to evaluate the efficacy of different group of fungicides as well as a biopesticide, including azoxystrobin, boscalid, fludioxonil, prothioconazole, tebuconazole, azoxystrobin/tebuconazole, boscalid/pyraclostrobin, prothioconazole/fluopyram and Bacillus amyloliquefaciens, on baseline sensitivity of S. sclerotiorum isolates under in-vitro conditions as well as control of SSR in the field. Artificial inoculation and mist irrigation prompt to reproducible SSR infection in oilseed rape cultivation. All compounds significantly reduced 36.7% to 86.9% SSR severity and increased 55.2% to 98.7% yield, 1.5% to 7.0% thousand grain-weight, 1.5% to 5.9% oil and 0.1% to 1.3% protein content. Fludioxonil, boscalid/pyraclostrobin and fluopyram/prothioconazole achieved strongest fungicidal activity against SSR. The biopesticide provided 36% of disease control. Under in vitro conditions, B. amyloliquefaciens not only strongly inhibited mycelial growth but also the formation of sclerotia in all concentrations. Boscalid and fludioxonil exhibited the highest level of fungicidal activity against S. sclerotiorum, with mean EC50 values of 1.23 and 1.60 μg a.s. mL−1. The highest variability of EC50 values between isolates was observed towards prothioconazole and azoxystrobin.

scholarly journals Baseline Sensitivity of Pyraclostrobin and Toxicity of SHAM to Sclerotinia sclerotiorum

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Jin-Li Li ◽  
Hong You ◽  
Fu-Xing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Inhibitory Effect ◽  
Oxidase Inhibitor ◽  
Cross Resistance ◽  
In Planta ◽  
Baseline Sensitivity ◽  
Vitro Assay ◽  
Quinone Outside Inhibitor

Sclerotinia sclerotiorum is a cosmopolitan plant pathogen notable for its wide host range. The quinone outside inhibitor (QoI) fungicide pyraclostrobin has not been registered for control of S. sclerotiorum in China. In this study, baseline sensitivity of pyraclostrobin was established based on effective concentration for 50% inhibition of mycelial growth (EC50) values of 153 isolates of S. sclerotiorum collected from five provinces of China and toxicity of alternative oxidase inhibitor salicylhydroxamic acid (SHAM) to S. sclerotiorum was determined. Results showed that the frequency distribution of EC50 values of the 153 isolates was unimodal but with a right-hand tail. The mean EC50 value was 0.1027 μg/ml and the range of EC50 values was 0.0124 to 0.6324 μg/ml. Applied as a preventive fungicide in pot experiments, pyraclostrobin at 5, 15, and 45 μg/ml provided control efficacies of 61, 77, and 100%, respectively. There was no positive cross-resistance between pyraclostrobin and carbendazim or dimethachlon. EC50 values for SHAM against four isolates of S. sclerotiorum were 44.4, 51.8, 54.4, and 68.7 μg/ml. SHAM at 20 μg/ml could significantly increase not only the inhibitory effect of pyraclostrobin on mycelial growth on potato dextrose agar media but also the control efficacy in planta. These results indicated that SHAM should not be added into artificial media in in vitro assay of S. sclerotiorum sensitivity to pyraclostrobin. This has broad implications for assay of sensitivity of fungal pathogen to QoI fungicides.

scholarly journals Detecting Pathogens of Verticillium Wilt in Winter Oilseed Rape Using ELISA and PCR – Comparison of the Two Methods and With Visual Stand Evaluation

2017 ◽  
Vol 65 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Tomáš Spitzer ◽  
Pavel Matušinsky
Keyword(s):  
Czech Republic ◽  
Oilseed Rape ◽  
Verticillium Wilt ◽  
Evaluation Methods ◽  
Winter Oilseed Rape ◽  
Visual Evaluation ◽  
The Czech Republic ◽  
Verticillium Longisporum ◽  
Main Species ◽  
Match Rate

During 2013–2015, oilseed rape samples from various locations in the Czech Republic were analysed for the presence of Verticillium wilt. Samples were evaluated in the lab using ELISA and PCR as well as by visual evaluation during the samples collection. A comparison of detection match in individual methods also was made. ELISA and PCR matched in detecting Verticillium wilt in 60 % of cases. For practical use, a higher match rate would be necessary in cases where samples were to be analysed in various laboratories using only one of these techniques. The possibility was demonstrated to use kits as well as primers not targeted specifically to just Verticillium longisporum but recording both main species on oilseed rape (V. longisporum and V. dahliae). The match rates of lab analyses with visual evaluation of stand infection were surprisingly high at 62 % for ELISA and 77 % for PCR. All three stand evaluation methods matched in 56 % of cases.

scholarly journals Meteorological Variables That Affect the Beginning of Flowering of the Winter Oilseed Rape in the Czech Republic

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1444
Author(s):  
Lenka Hájková ◽  
Martin Možný ◽  
Veronika Oušková ◽  
Lenka Bartošová ◽  
Petra Dížková ◽  
...  
Keyword(s):  
Czech Republic ◽  
Brassica Napus ◽  
Oilseed Rape ◽  
Air Temperature ◽  
Meteorological Variables ◽  
Base Temperature ◽  
Winter Oilseed Rape ◽  
Climatic Zones ◽  
The Czech Republic ◽  
Beginning Of Flowering

Winter oilseed rape (Brassica napus) is one of the most cultivated oilseeds in the Czech Republic and belongs among major pollen allergens. Pollen allergies have an extensive clinical impact worldwide, and as well as in the Czech Republic. In this paper, meteorological variables such as mean air temperature, maximum and minimum air temperature, precipitation total and number of rainy days in the period 1991–2012 were studied using the PhenoClim phenological model to find the best predictor of the beginning of flowering of the Brassica napus in the Czech Republic. In addition, temporal and spatial evaluations of the beginning of flowering of the Brassica napus were examined at individual stations in different climatic zones within the same period. In total, three phenological stations at altitudes from 270 m asl to 533 m asl located in warm (W2), medium warm (MW7) or cold (C7) climatic zones were used for detailed evaluation. Based on the observation results at selected stations, the beginning of flowering of the Brassica napus advanced progressively in timing (nearly −15 days) in the 1991–2012 period. The base temperature and temperature sums were calculated for the beginning of flowering of the winter oilseed rape using the PhenoClim computer tool. As the most accurate predictor for the beginning of flowering of the Brassica napus, the mean air temperature was determined. The optimal start day for calculation was 30th January, the threshold (base temperature) was 6.0 °C and the temperature sum was 157.0 °C. The RMSE value was 4.77 and the MBE value was −3.00. The simulated data had a good correlation with the real observed data (the correlation coefficients were within the range from 0.56 to 0.76), and the PhenoClim model results indicate using them in the forecast modeling of the beginning of flowering of the Brassica napus in the Czech Republic.

scholarly journals Sensitivity to fungicides in the isolates of Phytophthora infestans (Mont.) de Bary in the Czech Republic from 2003 to 2008

2011 ◽  
Vol 47 (No. 1) ◽  
pp. 5-12 ◽  
Author(s):  
J. Mazáková ◽  
M. Zouhar ◽  
P. Ryšánek ◽  
V. Táborský ◽  
E. Hausvater ◽  
...  
Keyword(s):  
Czech Republic ◽  
Phytophthora Infestans ◽  
Mycelial Growth ◽  
Leaf Disc ◽  
The Czech Republic ◽  
Growing Seasons ◽  
Leaf Disc Assay ◽  
Disc Assay ◽  
Floating Leaf

In the growing seasons from 2003 to 2008, 547 isolates of Phytophthora infestans from five regions in the Czech Republic were collected and examined for their sensitivity to the active ingredients (metalaxyl, dimethomorph and propamocarb-HCl) of frequently used fungicides. The response of the isolates to each of these substances was examined using the in vitro amended-agar method; in 352 of these isolates, the sensitivity to metalaxyl was also assessed by the floating leaf-disc assay. The majority of the isolates were sensitive (89.8%) to metalaxyl. Resistant isolates were found only in two of the sample years (2003 and 2008); they represented 58% of the samples in 2003 and only 29% in 2008. Four isolates from 2004 were found to be intermediate for their level of resistance. All the isolates that were tested were sensitive to dimethomorph and propamocarb-HCl; these particular substances completely suppressed mycelial growth at 1 &micro;g a.i. per ml.

scholarly journals Influence of application term on effectiveness of some insecticides against brassica pod midge (Dasineura brassicae Winn.)

2008 ◽  
Vol 43 (No. 2) ◽  
pp. 57-62 ◽  
Author(s):  
R. Pavela ◽  
J. Kazda ◽  
G. Herda
Keyword(s):  
Czech Republic ◽  
Oilseed Rape ◽  
Winter Oilseed Rape ◽  
The Czech Republic ◽  
Lambda Cyhalothrin ◽  
Full Flowering ◽  
Dasineura Brassicae

In 2005 we determined the effectiveness of two preparations against gall pod midge in dependence on different terms of application, i.e. at full flowering (BBCH 65) and after flowering (BBCH 67) of winter oilseed rape. The tests were carried out at three localities in the Czech Republic, and the two preparations used were Calypso 480 SC (a.i. thiacloprid) and Karate Zeon 5CS (a.i. lambda-cyhalothrin). It was found that applying the preparations at BBCH 67 was significantly more effective than treatment at BBCH 65.

scholarly journals Stimulatory Effects of Sublethal Doses of Dimethachlon on Sclerotinia sclerotiorum

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1364-1370 ◽  
Author(s):  
Feng Zhou ◽  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Hong You ◽  
Fu-Xing Zhu
Keyword(s):  
Oilseed Rape ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Plant Disease ◽  
Pathogenic Fungi ◽  
Potato Dextrose Agar ◽  
Detached Leaves ◽  
Sublethal Doses ◽  
Fungal Phytopathogens ◽  
Plant Disease Management

Growth and virulence stimulations of sublethal doses of fungicides on plant-pathogenic fungi and oomycetes have been reported and the stimulatory effects are potentially relevant to plant disease management. Sclerotinia sclerotiorum is one of the most devastating and economically important necrotrophic fungal phytopathogens, capable of infecting more than 400 species of plants worldwide. In order to study stimulatory effects of sublethal doses of fungicides on S. sclerotiorum, 55 dimethachlon-sensitive isolates and 3 dimethachlon-resistant isolates of S. sclerotiorum were assayed to determine effects of sublethal doses of dimethachlon on mycelial growth rate on potato dextrose agar (PDA) media and virulence on oilseed rape plants. Results showed that all 3 dimethachlon-resistant isolates and 13 of the 55 sensitive isolates exhibited stimulatory responses to sublethal doses of dimethachlon. Dimethachlon-resistant isolates grew significantly (P < 0.05) faster on PDA media amended with dimethachlon at 0.5 to 4 μg/ml than on fungicide-free PDA media. As for virulence on detached leaves of oilseed rape plants, lesion diameters of dimethachlon-resistant isolates after growth on PDA media amended with dimethachlon at 0.5 to 2 μg/ml were significantly larger (P < 0.05) than the control. The maximum stimulatory effects were 42.40 to 59.80%. In pot experiments, for both dimethachlon-sensitive and -resistant isolates, significant (P < 0.05) virulence stimulations were observed after spraying with dimethachlon at a concentration of 2 μg/ml. After growing on dimethachlon-amended PDA media, H2O2 sensitivity of S. sclerotiorum decreased significantly (P < 0.05) compared with the nonamended PDA control.

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