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Septoria tritici blotch (STB), caused by Zymoseptoria tritici, is one of the most important foliar wheat diseases worldwide. Current control strategies of STB rely mainly on fungicides, whereby triazoles (demethylation inhibitors; DMIs) have been the backbone in the control of Z. tritici in the last decades. However, in recent years a gradual loss of sensitivity of Z. tritici to several active ingredients of the triazole group has been reported in several European wheat-growing areas. Nevertheless, a new triazole fungicide, namely, mefentrifluconazole, has recently become available in disease management of STB, which belongs to a completely new triazole subclass, the so-called isopropanol triazoles. In this study, the trend in sensitivity development of Z. tritici towards older triazoles (tebuconazole, prothioconazole, and propiconazole) and the new isopropanol triazole mefentrifluconazole was determined in microtiter assays using Z. tritici field populations isolated in 1999, 2009, 2014, and 2020 in a high-disease-pressure and high-fungicide-input area in northern Germany in order to investigate whether the loss of sensitivity of Z. tritici to older triazoles also applies to mefentrifluconazole. For the three triazole fungicides tebuconazole, prothioconazole and propiconazole, a significant shift towards decreasing sensitivity of Z. tritici field populations was observed from 1999 to 2020, whereas the efficacy of mefentrifluconazole in reducing the in vitro fungal growth by 50% (EC50) remained unchanged over the investigated period, demonstrating a stable sensitivity of Z. tritici towards mefentrifluconazole. Although older triazoles are suffering from a loss of sensitivity of Z. tritici field populations due to the selection and spread of less triazole sensitive strains within the Z. tritici population, the efficacy of the new triazole mefentrifluconazole with its unique isopropanol unit was not affected by these changes within the Z. tritici population. Thus, the introduction of such new molecular units could also represent an important contribution for older groups of active ingredients, which previously suffered from a loss of sensitivity.
Holger Klink; Joseph-Alexander Verreet; Mario Hasler; Tim Birr. Will Triazoles Still Be of Importance in Disease Control of Zymoseptoria tritici in the Future? Agronomy 2021, 11, 933 .
AMA StyleHolger Klink, Joseph-Alexander Verreet, Mario Hasler, Tim Birr. Will Triazoles Still Be of Importance in Disease Control of Zymoseptoria tritici in the Future? Agronomy. 2021; 11 (5):933.
Chicago/Turabian StyleHolger Klink; Joseph-Alexander Verreet; Mario Hasler; Tim Birr. 2021. "Will Triazoles Still Be of Importance in Disease Control of Zymoseptoria tritici in the Future?" Agronomy 11, no. 5: 933.
Septoria tritici blotch (STB; Zymoseptoria tritici), one of the most important foliar diseases in wheat, is mainly controlled by the intensive use of fungicides during crop growth. Unfortunately, Z. tritici field populations have developed various extents of resistance to different groups of fungicides. Due to the complete resistance to quinone outside inhibitors (QoIs), fungicidal control of STB relies mainly on demethylation inhibitors (DMIs) and succinate dehydrogenase inhibitors (SDHIs) as well as multi-site inhibitors. In this study, temporal changes in the sensitivity of Z. tritici to selected DMIs (tebuconazole, propiconazole, prothioconazole, prochloraz), SDHIs (boscalid, bixafen), and multi-site inhibitors (chlorothalonil, folpet) were determined in microtiter assays using Z. tritici field populations isolated in 1999, 2009, 2014, and 2020 in a high-disease-pressure and high-fungicide-input area in Northern Germany. For the four tested DMI fungicides, a significant shift towards decreasing sensitivity of Z. tritici field populations was observed between 1999 and 2009, whereby concentrations inhibiting fungal growth by 50% (EC50) increased differentially between the four DMIs. Since 2009, EC50 values of tebuconazole, propiconazole, and prochloraz remain stable, whereas for prothioconazole a slightly increased sensitivity shift was found. A shift in sensitivity of Z. tritici was also determined for both tested SDHI fungicides. In contrast to DMIs, EC50 values of boscalid and bixafen increased continuously between 1999 and 2020, but the increasing EC50 values were much smaller compared to those of the four tested DMIs. No changes in sensitivity of Z. tritici were observed for the multi-site inhibitors chlorothalonil and folpet over the last 21 years. The sensitivity adaptation of Z. tritici to both groups of single-site inhibitors (DMIs, SDHIs) mainly used for STB control represents a major challenge for future wheat cultivation.
Tim Birr; Mario Hasler; Joseph-Alexander Verreet; Holger Klink. Temporal Changes in Sensitivity of Zymoseptoria tritici Field Populations to Different Fungicidal Modes of Action. Agriculture 2021, 11, 269 .
AMA StyleTim Birr, Mario Hasler, Joseph-Alexander Verreet, Holger Klink. Temporal Changes in Sensitivity of Zymoseptoria tritici Field Populations to Different Fungicidal Modes of Action. Agriculture. 2021; 11 (3):269.
Chicago/Turabian StyleTim Birr; Mario Hasler; Joseph-Alexander Verreet; Holger Klink. 2021. "Temporal Changes in Sensitivity of Zymoseptoria tritici Field Populations to Different Fungicidal Modes of Action." Agriculture 11, no. 3: 269.
Forage maize is often infected by mycotoxin-producing Fusarium fungi during plant growth, which represent a serious health risk to exposed animals. Deoxynivalenol (DON) and zearalenone (ZEN) are among the most important Fusarium mycotoxins, but little is known about the occurrence of their modified forms in forage maize. To assess the mycotoxin contamination in Northern Germany, 120 natural contaminated forage maize samples of four cultivars from several locations were analysed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) for DON and ZEN and their modified forms deoxynivalenol-3-glucoside (DON3G), the sum of 3- and 15-acetyl-deoxynivalenol (3+15-AcDON), α- and β-zearalenol (α-ZEL, β-ZEL). DON and ZEN occurred with high incidences (100 and 96%) and a wide range of concentrations, reaching levels up to 10,972 and 3910 µg/kg, respectively. Almost half of the samples (46%) exceeded the guidance value in complementary and complete feeding stuffs for ZEN (500 µg/kg), and 9% for DON (5000 µg/kg). The DON related mycotoxins DON3G and 3+15-AcDON were also present in almost all samples (100 and 97%) with amounts of up to 3038 and 2237 µg/kg and a wide range of concentrations. For the ZEN metabolites α- and β-ZEL lower incidences were detected (59 and 32%) with concentrations of up to 423 and 203 µg/kg, respectively. Forage maize samples were contaminated with at least three co-occurring mycotoxins, whereby 95% of all samples contained four or more mycotoxins with DON, DON3G, 3+15-AcDON, and ZEN co-occurring in 93%, together with α-ZEL in 57% of all samples. Positive correlations were established between concentrations of the co-occurring mycotoxins, especially between DON and its modified forms. Averaged over all samples, ratios of DON3G/DON and 3+15-AcDON/DON were similar, 20.2 and 20.5 mol%; cultivar-specific mean ratios ranged from 14.6 to 24.3 mol% and 15.8 to 24.0 mol%, respectively. In total, 40.7 mol% of the measured DON concentration was present in the modified forms DON3G and 3+15-AcDON. The α-ZEL/ZEN ratio was 6.2 mol%, ranging from 5.2 to 8.6 mol% between cultivars. These results demonstrate that modified mycotoxins contribute substantially to the overall mycotoxin contamination in forage maize. To avoid a considerable underestimation, it is necessary to analyse modified mycotoxins in future mycotoxin monitoring programs together with their parent forms.
Tim Birr; Tolke Jensen; Nils Preußke; Frank Sönnichsen; Marthe De Boevre; Sarah De Saeger; Mario Hasler; Joseph-Alexander Verreet; Holger Klink. Occurrence of Fusarium Mycotoxins and Their Modified Forms in Forage Maize Cultivars. Toxins 2021, 13, 110 .
AMA StyleTim Birr, Tolke Jensen, Nils Preußke, Frank Sönnichsen, Marthe De Boevre, Sarah De Saeger, Mario Hasler, Joseph-Alexander Verreet, Holger Klink. Occurrence of Fusarium Mycotoxins and Their Modified Forms in Forage Maize Cultivars. Toxins. 2021; 13 (2):110.
Chicago/Turabian StyleTim Birr; Tolke Jensen; Nils Preußke; Frank Sönnichsen; Marthe De Boevre; Sarah De Saeger; Mario Hasler; Joseph-Alexander Verreet; Holger Klink. 2021. "Occurrence of Fusarium Mycotoxins and Their Modified Forms in Forage Maize Cultivars." Toxins 13, no. 2: 110.
Fusarium head blight (FHB) is one of the most important diseases of wheat, causing yield losses and mycotoxin contamination of harvested grain. A complex of different toxigenic Fusarium species is responsible for FHB and the composition and predominance of species within the FHB complex are determined by meteorological and agronomic factors. In this study, grain of three different susceptible winter wheat cultivars from seven locations in northern Germany were analysed within a five-year survey from 2013 to 2017 by quantifying DNA amounts of different species within the Fusarium community as well as deoxynivalenol (DON) and zearalenone (ZEA) concentrations. Several Fusarium species co-occur in wheat grain samples in all years and cultivars. F. graminearum was the most prevalent species, followed by F. culmorum, F. avenaceum and F. poae, while F. tricinctum and F. langsethiae played only a subordinate role in the FHB complex in terms of DNA amounts. In all cultivars, a comparable year-specific quantitative occurrence of the six detected species and mycotoxin concentrations were found, but with decreased DNA amounts and mycotoxin concentrations in the more tolerant cultivars, especially in years with higher disease pressure. In all years, similar percentages of DNA amounts of the six species to the total Fusarium DNA amount of all detected species were found between the three cultivars for each species, with F. graminearum being the most dominant species. Differences in DNA amounts and DON and ZEA concentrations between growing seasons depended mainly on moisture factors during flowering of wheat, while high precipitation and relative humidity were the crucial meteorological factors for infection of wheat grain by Fusarium. Highly positive correlations were found between the meteorological variables precipitation and relative humidity and DNA amounts of F. graminearum, DON and ZEA concentrations during flowering, whereas the corresponding correlations were much weaker several days before (heading) and after flowering (early and late milk stage).
Tim Birr; Mario Hasler; Joseph-Alexander Verreet; Holger Klink. Composition and Predominance of Fusarium Species Causing Fusarium Head Blight in Winter Wheat Grain Depending on Cultivar Susceptibility and Meteorological Factors. Microorganisms 2020, 8, 617 .
AMA StyleTim Birr, Mario Hasler, Joseph-Alexander Verreet, Holger Klink. Composition and Predominance of Fusarium Species Causing Fusarium Head Blight in Winter Wheat Grain Depending on Cultivar Susceptibility and Meteorological Factors. Microorganisms. 2020; 8 (4):617.
Chicago/Turabian StyleTim Birr; Mario Hasler; Joseph-Alexander Verreet; Holger Klink. 2020. "Composition and Predominance of Fusarium Species Causing Fusarium Head Blight in Winter Wheat Grain Depending on Cultivar Susceptibility and Meteorological Factors." Microorganisms 8, no. 4: 617.
Real-time identification of the occurrence of dangerous pathogens is of crucial importance for the rapid execution of countermeasures. For this purpose, spatial and temporal predictions of the spread of such pathogens are indispensable. The R package papros developed by the authors offers an environment in which both spatial and temporal predictions can be made, based on local data using various deterministic, geostatistical regionalisation, and machine learning methods. The approach is presented using the example of a crops infection by fungal pathogens, which can substantially reduce the yield if not treated in good time. The situation is made more difficult by the fact that it is particularly difficult to predict the behaviour of wind-dispersed pathogens, such as powdery mildew (Blumeria graminis f. sp. tritici). To forecast pathogen development and spatial dispersal, a modelling process scheme was developed using the aforementioned R package, which combines regionalisation and machine learning techniques. It enables the prediction of the probability of yield- relevant infestation events for an entire federal state in northern Germany at a daily time scale. To run the models, weather and climate information are required, as is knowledge of the pathogen biology. Once fitted to the pathogen, only weather and climate information are necessary to predict such events, with an overall accuracy of 68% in the case of powdery mildew at a regional scale. Thereby, 91% of the observed powdery mildew events are predicted.
Wolfgang B. Hamer; Tim Birr; Joseph-Alexander Verreet; Rainer Duttmann; Holger Klink. Spatio-Temporal Prediction of the Epidemic Spread of Dangerous Pathogens Using Machine Learning Methods. ISPRS International Journal of Geo-Information 2020, 9, 44 .
AMA StyleWolfgang B. Hamer, Tim Birr, Joseph-Alexander Verreet, Rainer Duttmann, Holger Klink. Spatio-Temporal Prediction of the Epidemic Spread of Dangerous Pathogens Using Machine Learning Methods. ISPRS International Journal of Geo-Information. 2020; 9 (1):44.
Chicago/Turabian StyleWolfgang B. Hamer; Tim Birr; Joseph-Alexander Verreet; Rainer Duttmann; Holger Klink. 2020. "Spatio-Temporal Prediction of the Epidemic Spread of Dangerous Pathogens Using Machine Learning Methods." ISPRS International Journal of Geo-Information 9, no. 1: 44.
The selective and sensitive analysis of mycotoxins in highly complex feed matrices is a great challenge. In this study, the suitability of OrbitrapTM-based high-resolution mass spectrometry (HRMS) for routine mycotoxin analysis in complex feeds was demonstrated by the successful validation of a full MS/data-dependent MS/MS acquisition method for the quantitative determination of eight Fusarium mycotoxins in forage maize and maize silage according to the Commission Decision 2002/657/EC. The required resolving power for accurate mass assignments (A), intra-day precision (RSDr), and inter-day precision (RSDR) of measurements were in the range of 94 to 108%, 2 to 16%, and 2 to 12%, whereas the decision limit (CCα) and the detection capability (CCβ) varied from 11 to 88 µg/kg and 20 to 141 µg/kg, respectively. A set of naturally contaminated forage maize and maize silage samples collected in northern Germany in 2017 was analyzed to confirm the applicability of the HRMS method to real samples. At least four Fusarium mycotoxins were quantified in each sample, highlighting the frequent co-occurrence of mycotoxins in feed.
Tolke Jensen; Marthe de Boevre; Nils Preußke; Sarah de Saeger; Tim Birr; Joseph-Alexander Verreet; Frank Sönnichsen. Evaluation of High-Resolution Mass Spectrometry for the Quantitative Analysis of Mycotoxins in Complex Feed Matrices. Toxins 2019, 11, 531 .
AMA StyleTolke Jensen, Marthe de Boevre, Nils Preußke, Sarah de Saeger, Tim Birr, Joseph-Alexander Verreet, Frank Sönnichsen. Evaluation of High-Resolution Mass Spectrometry for the Quantitative Analysis of Mycotoxins in Complex Feed Matrices. Toxins. 2019; 11 (9):531.
Chicago/Turabian StyleTolke Jensen; Marthe de Boevre; Nils Preußke; Sarah de Saeger; Tim Birr; Joseph-Alexander Verreet; Frank Sönnichsen. 2019. "Evaluation of High-Resolution Mass Spectrometry for the Quantitative Analysis of Mycotoxins in Complex Feed Matrices." Toxins 11, no. 9: 531.
Grains of the three differentially Fusarium-susceptible winter wheat cultivars “Ritmo” (highly susceptible), “Inspiration” (moderately to highly susceptible) and “Dekan” (lowly to moderately susceptible) from up to eight trial locations in Schleswig-Holstein (Northern Germany) and maize-free crop rotations were analysed for their mycotoxin concentration from 2008 to 2017 (“Inspiration” and “Dekan” since 2012). The deoxynivalenol (DON) and zearalenone (ZEA) concentrations of wheat grain samples differed significantly between individual years and within each year between the trial locations due to weather conditions during flowering. Significant relationships were found between the two weather variables cumulative precipitation (added up by all daily cumulative precipitation) and average temperature (averaged for all daily means of temperature) during the period of wheat flowering and DON and ZEA concentrations in wheat grain at harvest. These relationships were determined for “Ritmo” from 2008 to 2014 (\(R^{2}_{{{\text{adj}} .}}\) = 0.81 for DON; \(R^{2}_{{{\text{adj}} .}}\) = 0.75 for ZEA) and for both “Inspiration” (\(R^{2}_{{{\text{adj}} .}}\) = 0.84 for DON; \(R^{2}_{{{\text{adj}} .}}\) = 0.82 for ZEA) and “Dekan” (\(R^{2}_{{{\text{adj}} .}}\) = 0.78 for DON; \(R^{2}_{{{\text{adj}} .}}\) = 0.77 for ZEA) from 2012 to 2016. Based on this, multiple regression models were developed for the three cultivars for the prediction of DON and ZEA contamination in wheat grain: model 1 = highly susceptible; model 2 = moderately to highly susceptible; model 3 = lowly to moderately susceptible. The models included the covariates cumulative precipitation and average temperature during wheat flowering and the interaction term of precipitation and temperature. The predictive power of the three models was evaluated with data not utilized in the development of the models, i.e. weather conditions during wheat flowering and DON and ZEA concentrations in wheat grain at harvest at the same trial locations in the years 2015 to 2017 for model 1 and in 2017 for model 2 and model 3. The models showed a high predictive power by regressing observed versus predicted values (model 1: R2 = 0.89 for DON, R2 = 0.91 for ZEA; model 2: R2 = 0.91 for DON, R2 = 0.84 for ZEA; model 3: R2 = 0.86 for DON, R2 = 0.89 for ZEA). Model 1 predicted correctly whether the concentrations of DON and ZEA were either lower or higher than the European maximum levels of 1250 µg DON/kg and 100 µg ZEA/kg in 95.2% of the cases. Models 2 and 3 performed 85.7% and 100% correct predictions for DON in 2017, respectively. Model 2 predicted correctly whether the ZEA concentration was either lower or higher than the maximum level of 100 µg ZEA/kg in 100% of the cases in 2017, whereas model 3 performed 85.7% correct predictions. The models are therefore useful for the prediction of DON and ZEA concentrations in wheat grain from maize-free crop rotations based on cumulative precipitation and average temperature during wheat flowering and for differentially susceptible wheat cultivars.
Tim Birr; Joseph-Alexander Verreet; Holger Klink. Prediction of deoxynivalenol and zearalenone in winter wheat grain in a maize-free crop rotation based on cultivar susceptibility and meteorological factors. Journal of Plant Diseases and Protection 2018, 126, 13 -27.
AMA StyleTim Birr, Joseph-Alexander Verreet, Holger Klink. Prediction of deoxynivalenol and zearalenone in winter wheat grain in a maize-free crop rotation based on cultivar susceptibility and meteorological factors. Journal of Plant Diseases and Protection. 2018; 126 (1):13-27.
Chicago/Turabian StyleTim Birr; Joseph-Alexander Verreet; Holger Klink. 2018. "Prediction of deoxynivalenol and zearalenone in winter wheat grain in a maize-free crop rotation based on cultivar susceptibility and meteorological factors." Journal of Plant Diseases and Protection 126, no. 1: 13-27.