scholarly journals Fungicide strategies and resistance of Ramularia collo-cygni to demethylation and succinate dehydrogenase inhibitors in Austrian winter barley (Hordeum vulgare)

2021 ◽  
Author(s):  
Thomas Assinger ◽  
Stefano F. F. Torriani ◽  
Salvatore Accardo ◽  
James Fountaine ◽  
Siegrid Steinkellner
Keyword(s):  
Succinate Dehydrogenase ◽  
Fungicide Resistance ◽  
Growth Parameters ◽  
Field Trials ◽  
Low Frequencies ◽  
Resistance Strategies ◽  
Growing Seasons ◽  
Ramularia Leaf Spot ◽  
Application Frequency ◽  
Succinate Dehydrogenase Inhibitors

AbstractRamularia collo-cygni B. Sutton and J.M. Waller is a major disease in Austrian barley-growing regions. To date, fungicide application is the most effective method to manage the disease; however, fungicide resistance to demethylation and succinate dehydrogenase inhibitors has developed over the last few years. In the growing seasons 2016/2017 and 2017/2018, field trials were carried out to analyze the efficiency of fungicide strategies based on different fungicide classes. Disease development, growth parameters and monitoring of CYP51 and sdh mutations were determined. Fungicide treatments resulted in higher disease control, green leaf area and grain yield. In Austrian R. collo-cygni field populations, the frequency of the mutations CYP51-I325T and CYP51-I328L was low to moderate. Frequency of mutations sdhC-H146R and sdhC-H153R was low. Frequencies of CYP51-I325T and -I328L were similar and increased following DMI application. Frequency of sdhC-H146R was higher compared to sdhC-H153R. The SDHI benzovindiflupyr showed a higher selection rate for sdh mutations compared to bixafen. These sdh mutations were not selected if chlorothalonil was used as mixing partner, leading to a stable composition of sdh resistance alleles over the last two years. Chlorothalonil was proven to be an effective tool for anti-resistance strategies. Currently, SDHIs and DMIs are the backbone of Ramularia leaf spot control in Austria; however, the level of resistance is likely to increase in absence of suitable anti-resistance strategies and following the ban of chlorothalonil.

scholarly journals Fungicide Resistance Evolving in Ramularia Collo-Cygni Population in Estonia

2021 ◽  
Vol 9 (7) ◽  
pp. 1514
Author(s):  
Riinu Kiiker ◽  
Marite Juurik ◽  
Andres Mäe
Keyword(s):  
Disease Control ◽  
High Resistance ◽  
Fungicide Resistance ◽  
Spring Barley ◽  
Point Mutations ◽  
Ramularia Leaf Spot ◽  
Entire Collection ◽  
Dmi Fungicides ◽  
Fungicide Target ◽  
Succinate Dehydrogenase Inhibitors

Ramularia leaf spot caused by the fungus Ramularia collo-cygni, has recently become widespread in Estonian barley fields. Currently, disease control in barley fields relies on SDHI and DMI fungicides, which might be threatened by R. collo-cygni isolates that are well-adapted to fungicide pressure. In a two-year study, 353 R. collo-cygni isolates were collected from spring barley fields in Estonia. A total of 153 R. collo-cygni isolates were examined for sensitivity to azoles (DMIs; prothioconazole-desthio, epoxiconazole, mefentrifluconazole) and succinate dehydrogenase inhibitors (SDHIs; boscalid, fluxapyroxad). Epoxiconazole was the least effective and a new fungicide mefentrifluconazole was the most effective DMI. Among SDHIs, fluxapyroxad was more effective than boscalid. Also, single R. collo-cygni isolates with high resistance to tested fungicides occurred, which could affect fungicide control of the pathogen. The entire collection of R. collo-cygni was analysed for mutations in fungicide target proteins. Six mutations were identified in CYP51 gene, the most dominant being I381T, I384T, and S459C. Also, numerous point mutations in the SdhC gene were present. The mutation G143A in strobilurin target protein CytB dominates in over 80% of the R. collo-cygni population, confirming the low efficacy of strobilurin fungicides in barley disease control.

scholarly journals Assessing crop performance in maize field trials using a vegetation index

2018 ◽  
Vol 3 (1) ◽  
pp. 250-263
Author(s):  
Carl-Philipp Federolf ◽  
Matthias Westerschulte ◽  
Hans-Werner Olfs ◽  
Gabriele Broll ◽  
Dieter Trautz
Keyword(s):  
Vegetation Index ◽  
Growth Parameters ◽  
Field Trials ◽  
Growth Stages ◽  
Growing Seasons ◽  
Cropping Season ◽  
Application Techniques ◽  
Series Of Experiments ◽  
Growth Differences ◽  
Different Growth Stages

Abstract New agronomic systems need scientific proof before being adapted by farmers. To increase the informative value of field trials, expensive samplings throughout the cropping season are required. In a series of trials where different application techniques and rates of liquid manure in maize were tested, a handheld sensor metering the red edge inflection point (REIP) was compared to conventional biomass sampling at different growth stages and in different environments. In a repeatedly measured trial during the 2014, 2015, and 2016 growing seasons, the coefficients of determination between REIP and biomass / nitrogen uptake (Nupt) ascended from 4 leaves stage to 8 leaves stage, followed by a decent towards tasseling. In a series of trials in 2014, and 2015, the mean coefficients of determination at 8 leaves stage were 0.65, and 0.67 for biomass and Nupt, respectively. The predictability of biomass or Nupt by REIP however, is limited to similar conditions (e.g. variety). In this study, REIP values of e.g. ~721, represent Nupt values from ~8 kg ha-1 to ~38 kg ha-1. Consequently, the handheld sensor derived REIP used in this series of experiments can show growth differences between treatments, but referential samples are necessary to assess growth parameters.

Fungicide sensitivity of Colletotrichum species causing bitter rot of apple in the Mid-Atlantic United States

Plant Disease ◽  
2021 ◽  
Author(s):  
Phillip L. Martin ◽  
Teresa Krawczyk ◽  
Kristen Pierce ◽  
Catherine Anne Thomas ◽  
Fatemeh Khodadadi ◽  
...  
Keyword(s):  
United States ◽  
Fungicide Resistance ◽  
Single Mode ◽  
The United States ◽  
Field Trials ◽  
In Vitro Tests ◽  
Atlantic Region ◽  
Low Frequencies ◽  
Bitter Rot

Apple growers in the Mid-Atlantic region of the United States have reported increased losses to bitter rot of apple. We tested the hypothesis that this increase is because the Colletotrichum population has developed resistance to commonly used single-mode-of-action (single-MoA) fungicides. We screened 220 Colletotrichum isolates obtained from 38 apple orchards in the Mid-Atlantic region for resistance to 11 fungicides in FRAC (Fungicide Resistance Action Committee) groups 1, 7, 9, 11, 12, and 29. Eleven (5%) of these isolates were resistant to FRAC group 1 with confirmed beta-tubulin E198A mutations, and two (< 1%) were also resistant to FRAC group 11 with confirmed cytochrome-b G143A mutations. Such low frequencies of resistant isolates indicate that fungicide resistance is unlikely to be the cause of any regional increase in bitter rot. A subsample of isolates was subsequently tested in vitro for sensitivity to every single-MoA fungicide registered for apple in the Mid-Atlantic US (22 fungicides; FRAC groups 1, 3, 7, 9, 11, 12, and 29), and thirteen fungicides were tested in field trials. These fungicides varied widely in efficacy both within and between FRAC groups. Comparisons of results from our in vitro tests with results from our field trials and other field trials conducted across the Eastern US suggested that EC₂₅ values (concentrations that reduce growth by 25%) are better predictors of fungicide efficacy in normal field conditions than EC₅₀ values. We present these results as a guideline for choosing single-MoA fungicides for bitter rot control in the Mid-Atlantic US.

The effect of seed rate and growing season on four oat cultivars: II. Culm morphology and panicle conformation

1968 ◽  
Vol 70 (3) ◽  
pp. 405-410 ◽  
Author(s):  
I. T. Jones ◽  
J. D. Hayes
Keyword(s):  
Relative Length ◽  
Field Trials ◽  
Grain Weight ◽  
Seed Rate ◽  
Total Height ◽  
Growing Seasons ◽  
Length Increase ◽  
Total Plant ◽  
Oat Cultivars ◽  
1000 Grain Weight

SUMMARYThe effects of low and high seed rates on height, culm and panicle morphology of four oat cultivars grown in field trials in two growing seasons were investigated. Significant differences were detected between cultivars in the number of extended culm internodes, panicle whorls initiated, total height, length of panicle and individual internodes. Differences in seed rate had no effect on the number of culm internodes, but high seed rate significantly reduced the whorl number in the panicle, total plant height, length of panicle and the three upper internodes. The fourth internode remained unaffected, but the lowermost internode showed a relative length increase at high seed rate. The interaction of cultivar x seed rate was significant for total height, and for the length of the central internodes, but the length of the panicle was similarly affected in all cultivars.Panicle conformation was markedly affected by seed rate; high population density caused a reduction in number of grain-bearing whorls, and reduced the number of spikelets and total grain weight per whorl, and 1000 grain weight particularly in the lowermost whorls. The percentage of husk in the grain was increased slightly at high seed rate. The effect of seed rate on culm and panicle morphology is discussed in relation to the development of stiffer-strawed oats.

Expanding the Chemical Space of Succinate Dehydrogenase Inhibitors via the Carbon–Silicon Switch Strategy

2021 ◽  
Vol 69 (13) ◽  
pp. 3965-3971
Author(s):  
Ge Wei ◽  
Ming-Wei Huang ◽  
Wen-Jie Wang ◽  
Yuan Wu ◽  
Shu-Fen Mei ◽  
...  
Keyword(s):  
Succinate Dehydrogenase ◽  
Chemical Space ◽  
Switch Strategy ◽  
Succinate Dehydrogenase Inhibitors

scholarly journals Wheat Grain Protein Content under Mediterranean Conditions Measured with Chlorophyll Meter

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 374
Author(s):  
Marta Aranguren ◽  
Ander Castellón ◽  
Ana Aizpurua
Keyword(s):  
Protein Content ◽  
Stem Elongation ◽  
Field Trials ◽  
Grain Protein Content ◽  
Grain Protein ◽  
Bread Making ◽  
High Quality ◽  
Chlorophyll Meter ◽  
Growing Seasons ◽  
Different Sources

Adequate N fertilisation is crucial to increase the grain protein content (GPC) values in wheat. The recommended level of GPC needed to achieve high-quality bread-making flour should be higher than 12.5%. However, it is difficult to ensure the GPC values that the crop will achieve because N in grain is derived from two different sources: N remobilized into the grain from N accumulated in the pre-anthesis period, and N absorbed from the soil in the post-anthesis period. This study aimed to (i) evaluate the effect of the application of N on the rate of stem elongation (GS30) when farmyard manures are applied as initial fertilisers on GPC and on the chlorophyll meter (CM) values at mid-anthesis (GS65), (ii) establish a relationship between the CM values at GS65 and GPC, and (iii) determine a minimum CM value at GS65 to obtain GPC values above 12.5%. Three field trials were performed in three consecutive growing seasons, and different N fertilisation doses were applied. Readings using the CM Yara N-TesterTM were taken at GS65. The type of initial fertiliser did not affect the GPC and CM values. Generally, the greater the N application at GS30 is, the higher the GPC and CM values are. CM values can help to estimate GPC values only when yields are below 8000 kg ha−1. Additionally, CM values at GS65 should be higher than 700 to achieve high-quality bread-making flour (12.5%) at such yield levels. These results will allow farmers and cooperatives to make better decisions regarding late-nitrogen fertilisation and wheat sales.

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