scholarly journals Head Blight Gradients Caused by Gibberella zeae from Area Sources of Inoculum in Wheat Field Plots

1997 ◽  
Vol 87 (4) ◽  
pp. 414-421 ◽  
Author(s):  
W. G. D. Fernando ◽  
T. C. Paulitz ◽  
W. L. Seaman ◽  
P. Dutilleul ◽  
J. D. Miller
Keyword(s):  
Fusarium Head Blight ◽  
Disease Incidence ◽  
Gibberella Zeae ◽  
Head Blight ◽  
Direction Parallel ◽  
Inoculum Source ◽  
Inoculation Method ◽  
Short Period ◽  
Corn Kernels ◽  
Disease Foci

The spread of Fusarium head blight of wheat from a small area inoculum source was examined in wheat plots (100, 625, or 2,500 m2) inoculated in the center with Gibberella zeae-colonized corn kernels or macro-conidia sprayed on heads at anthesis. With the first inoculation method, disease foci were produced from ascospores released from perithecia formed on inoculated kernels. With the second inoculation method, disease foci were produced by macroconidia directly applied to the heads. Some plots were misted during anthesis. Plots were divided into grids, and disease incidence on spikelets and seeds was assessed at the grid intersections. Isopath contour maps were constructed using an interpolation procedure based on a weighted least squares method. Disease gradients were constructed from the isopath contours in the direction parallel to average nightly wind vectors using an exponential model. This study was conducted over a 3-year period at two sites: one in Quebec and one in Ontario. Both inoculation methods resulted in a discrete, primary focus of head blight in each plot, with one or two smaller secondary foci in some plots. The highest incidence of disease on spikelets or seed was commonly displaced somewhat from the inoculum source, usually downwind. The gradient slopes of seed and spikelet infection ranged from −0.10 to −0.43 m−1 in plots with ascospore inoculum and from −0.48 to −0.79 m−1 in plots inoculated with macroconidia. Seed infection declined to 10% of the maximum within 5 to 22 m from the focal center in asco-spore-inoculated plots, and within 5 m in a macroconidia-inoculated plot. Gradients were usually steeper upwind compared with downwind of the inoculum source. In misted plots, incidence of disease was higher and more diffuse than in nonirrigated plots. Based on gradients and dispersal patterns, disease foci in plots inoculated with G. zeae-colonized corn kernels probably arose from airborne ascospores rather than from splash-borne macroconidia and were the result of infection events that occurred over a short period of time. Comparison of conidial- and ascospore-derived disease gradients indicated a lack of secondary infection, confirming that Fusarium head blight is primarily a monocyclic disease.

scholarly journals Anthesis, the infectious process and disease progress curves for fusarium head blight in wheat

2016 ◽  
Vol 42 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Erlei Melo Reis ◽  
Cristina Boareto ◽  
Anderson Luiz Durante Danelli ◽  
Sandra Maria Zoldan
Keyword(s):  
Fusarium Head Blight ◽  
Disease Incidence ◽  
Weather Conditions ◽  
Gibberella Zeae ◽  
Head Blight ◽  
Infectious Process ◽  
Disease Progress ◽  
Winter Cereals ◽  
Aggregation Pattern ◽  
Adverse Weather

ABSTRACT Fusarium head blight of wheat (Triticum aestivum), caused by the fungus Gibberella zeae, is a floral infecting disease that causes quantitative and qualitative losses to winter cereals. In Brazil, the sanitary situation of wheat has led to research in order to develop strategies for sustainable production, even under adverse weather conditions. To increase the knowledge of the relationship among the presence of anthesis, the infectious process, the disease progress and the saprophytic fungi present in wheat anthers, studies were conducted in the experimental field of University of Passo Fundo (UPF), using the cultivar Marfim, in the 2011 growing season. The disease incidence in spikes and spikelets was evaluated. The presence of exserted anthers increased the spike exposure time to the inoculum. The final incidence of fusarium head blight, in the field, was dependent on the presence of exserted anthers. The disease followed an aggregation pattern and its evolution increased with time, apparently showing growth according to secondary cycles. The fungi isolated from exserted anthers (Alternaria sp., Fusarium sp., Drechslera spp. and Epicoccum sp.) did not compete for the infection site of fusarium head blight in wheat, not interfering with the incidence of F. graminearum.

scholarly journals Fusarium Head Blight Severity and Deoxynivalenol Concentration in Wheat in Response to Gibberella zeae Inoculum Concentration

2009 ◽  
Vol 99 (6) ◽  
pp. 759-764 ◽  
Author(s):  
J. M. Stein ◽  
L. E. Osborne ◽  
K. D. Bondalapati ◽  
K. D. Glover ◽  
C. A. Nelson
Keyword(s):  
Fusarium Head Blight ◽  
Disease Incidence ◽  
Field Studies ◽  
Gibberella Zeae ◽  
Linear Functions ◽  
Head Blight ◽  
Fusarium Head Blight Severity ◽  
Negative Exponential Function ◽  
Inoculum Concentration ◽  
Inoculum Dose

The relationship between inoculum dose and resulting disease levels and deoxynivalenol (DON) accumulation in the Fusarium head blight (FHB) of wheat pathosystem was examined under controlled conditions. Greenhouse-grown spring wheat plants were inoculated at flowering with suspensions that varied in Gibberella zeae macroconidia concentration. The spikes were bagged for 72 h to promote infection and plants were then kept under ambient greenhouse conditions and disease allowed to develop. Spikes were rated at 15 days after inoculation for disease incidence and severity, removed from the greenhouse, and dried. DON concentration was determined in grain-only and whole-spike samples for each inoculation treatment. Regression analysis was used to evaluate the mathematical relationship between inoculum dose and the (i) disease metrics or (ii) DON concentration. Both disease incidence and severity were found to increase sharply in relation to inoculum concentration until an asymptote was reached. In both instances, a negative exponential function was found to best explain this relationship. By contrast, DON concentration in both grain-only and whole-spike tissues increased with additional inoculum. These relationships were best explained with linear functions for both sample types, although DON accumulation increased at a greater rate in whole-spike tissue. The functions were evaluated further using data collected from unrelated field studies and, although not particularly consistent, provided reasonably accurate predictions in growing seasons when the environment was only moderately favorable for FHB.

Comparing Genetic Variation within Red Winter Wheat Populations with and without Image-Based Optical Sorter Selection

2019 ◽  
Vol 9 (2) ◽  
pp. 266-277
Author(s):  
Hussein M. Khaeim ◽  
Anthony Clark ◽  
Tom Pearson ◽  
Dr. David Van Sanford
Keyword(s):  
Genetic Variation ◽  
Fusarium Head Blight ◽  
Heading Date ◽  
Fusarium Head Blight Resistance ◽  
Gibberella Zeae ◽  
Mass Selection ◽  
Head Blight ◽  
Red Winter Wheat ◽  
Two Populations ◽  
Head Scab

Head scab is historically a devastating disease affecting not just all classes of wheat but also barley and other small grains around the world. Fusarium head blight (FHB), or head scab, is caused most often by Fusarium graminearum (Schwabe), (sexual stage – Gibberella zeae) although several Fusarium spp. can cause the disease. This study was conducted to determine the effect of mass selection for FHB resistance using an image-based optical sorter. lines were derived from the C0 and C2 of two populations to compare genetic variation within populations with and without sorter selection. Our overall hypothesis is that sorting grain results in improved Fusarium head blight resistance. Both of the used wheat derived line populations have genetic variation, and population 1 has more than population 17. They are significantly different from each other for fusarium damged kernel (FDK), deoxynivalenol (DON), and other FHB traits. Although both populations are suitable to be grown for bulks, population 1 seems better since it has more genetic variation as well as lower FDK and DON, and earlier heading date. Lines within each population were significantly different and some lines in each population had significantly lower FDK and DON after selection using an optical sorter. Some lines had significant reduction in both FDK and DON, and some others had either FDK or DON reduction. Lines of population 1 that had significant reduction, were more numerous than in population 17, and FDK and DON reduction were greater.

scholarly journals Screening of Durum Wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.) Italian Cultivars for Susceptibility to Fusarium Head Blight Incited by Fusarium graminearum

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 68
Author(s):  
Gaetano Bentivenga ◽  
Alfio Spina ◽  
Karim Ammar ◽  
Maria Allegra ◽  
Santa Olga Cacciola
Keyword(s):  
Durum Wheat ◽  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Triticum Turgidum ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Conidial Suspension ◽  
Head Blight ◽  
Italian Origin

In 2009, a set of 35 cultivars of durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.) of Italian origin was screened for fusarium head blight (FHB) susceptibility at CIMMYT (Mexico) and in the 2019–20 cropping season, 16 of these cultivars, which had been included in the Italian National Plant Variety Register, were tested again in southern and northern Italy. Wheat cultivars were artificially inoculated during anthesis with a conidial suspension of Fusarium graminearum sensu lato using a standard spray inoculation method. Inoculum was a mixture of mono-conidial isolates sourced in the same areas where the trials were performed. Isolates had been characterized on the basis of morphological characteristics and by DNA PCR amplification using a specific primer set and then selected for their virulence and ability to produce mycotoxins. The susceptibility to FHB was rated on the basis of the disease severity, disease incidence and FHB index. Almost all of the tested cultivars were susceptible or very susceptible to FHB with the only exception of “Duprì”, “Tiziana” and “Dylan” which proved to be moderately susceptible. The susceptibility to FHB was inversely correlated with the plant height and flowering biology, the tall and the late heading cultivars being less susceptible.

Biological management of Fusarium head blight and mycotoxin contamination in wheat

2009 ◽  
Vol 2 (2) ◽  
pp. 193-201 ◽  
Author(s):  
A. Xue ◽  
H. Voldeng ◽  
M. Savard ◽  
G. Fedak
Keyword(s):  
Fusarium Head Blight ◽  
Field Experiments ◽  
Control Measure ◽  
Field Trials ◽  
Management Program ◽  
Gibberella Zeae ◽  
Head Blight ◽  
Wheat Field ◽  
Mycotoxin Contamination ◽  
Better Than

Fusarium head blight (FHB), caused by Gibberella zeae is a harmful disease of wheat. To manage FHB and mycotoxin contamination in wheat, field experiments were conducted from 2007 to 2008 to evaluate a total of 20 selected bioagents for their ability to inhibit perithecial production of G. zeae and for the control of FHB and deoxynivalenol (DON) contamination, in comparison with the registered fungicide Folicur (tebuconazole). All 20 bioagents significantly reduced the perithecial production compared to the untreated control. Clonostachy rosea strain ACM941 was the most effective treatment, reducing the production of perithecia by 63.7% in 2007 and 67.5% in 2008. These effects were significantly better than Folicur fungicide, which reduced perithecial production by 30.4% and 20.5%, for 2007 and 2008, respectively. When sprayed on to wheat heads, seven of the 20 bioagents significantly reduced the FHB index, one reduced Fusarium damaged kernels (FDK), and six reduced DON content in grains in 2007. ACM941 was the only treatment that significantly reduced FHB index, FDK, and DON, by 46.4%, 29.0% and 28.7%, respectively. Among the six bioagents and three formulated products evaluated in two separate field trials in 2008, ACM941 and its formulated product ACM941-CU were the only treatments that significantly reduced FHB index, FDK, and DON. The treatments reduced FHB index by 30.8% and 31.4%, FDK by 17.8% and 43.8%, and DON by 30.8% and 37.1%, for ACM941 and ACM941-CU, respectively. These effects were less marked than those of the Folicur fungicide that reduced FHB index by 98.8%, FDK by 94.2%, and DON by 92.1%. Results of this study suggest that ACM941 is a promising bioagent against G. zeae and may be used as a control measure in organic farming and in an integrated FHB and DON management program for wheat production.

scholarly journals Characterizing Heterogeneity of Disease Incidence in a Spatial Hierarchy: A Case Study from a Decade of Observations of Fusarium Head Blight of Wheat

2012 ◽  
Vol 102 (9) ◽  
pp. 867-877 ◽  
Author(s):  
A. B. Kriss ◽  
P. A. Paul ◽  
L. V. Madden
Keyword(s):  
Spatial Heterogeneity ◽  
Fusarium Head Blight ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Disease Incidence ◽  
Geographical Location ◽  
Disease Status ◽  
Link Function ◽  
Head Blight ◽  
Growing Seasons

A multilevel analysis of heterogeneity of disease incidence was conducted based on observations of Fusarium head blight (caused by Fusarium graminearum) in Ohio during the 2002–11 growing seasons. Sampling consisted of counting the number of diseased and healthy wheat spikes per 0.3 m of row at 10 sites (about 30 m apart) in a total of 67 to 159 sampled fields in 12 to 32 sampled counties per year. Incidence was then determined as the proportion of diseased spikes at each site. Spatial heterogeneity of incidence among counties, fields within counties, and sites within fields and counties was characterized by fitting a generalized linear mixed model to the data, using a complementary log-log link function, with the assumption that the disease status of spikes was binomially distributed conditional on the effects of county, field, and site. Based on the estimated variance terms, there was highly significant spatial heterogeneity among counties and among fields within counties each year; magnitude of the estimated variances was similar for counties and fields. The lowest level of heterogeneity was among sites within fields, and the site variance was either 0 or not significantly greater than 0 in 3 of the 10 years. Based on the variances, the intracluster correlation of disease status of spikes within sites indicated that spikes from the same site were somewhat more likely to share the same disease status relative to spikes from other sites, fields, or counties. The estimated best linear unbiased predictor (EBLUP) for each county was determined, showing large differences across the state in disease incidence (as represented by the link function of the estimated probability that a spike was diseased) but no consistency between years for the different counties. The effects of geographical location, corn and wheat acreage per county, and environmental conditions on the EBLUP for each county were not significant in the majority of years.

Field testing of antagonists of Fusarium head blight incited by Gibberella zeae

2004 ◽  
Vol 29 (2) ◽  
pp. 245-255 ◽  
Author(s):  
N.I Khan ◽  
D.A Schisler ◽  
M.J Boehm ◽  
P.E Lipps ◽  
P.J Slininger
Keyword(s):  
Fusarium Head Blight ◽  
Field Testing ◽  
Gibberella Zeae ◽  
Head Blight

Fusarium head blight development and trichothecene accumulation in point inoculated Fusarium infected wheat heads

2012 ◽  
Vol 5 (1) ◽  
pp. 45-55 ◽  
Author(s):  
P. Gautam ◽  
R. Dill-Macky
Keyword(s):  
Fusarium Head Blight ◽  
Gibberella Zeae ◽  
Growth Stages ◽  
Wheat Cultivars ◽  
Yield Losses ◽  
Head Blight ◽  
Moderately Resistant ◽  
Dough Stage ◽  
Different Growth Stages ◽  
Important Disease

Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein) Petch] is the predominant causal agent of Fusarium head blight (FHB), an economically important disease of wheat, in North America. Warm and humid environments at and shortly after anthesis favour FHB. FHB results in yield losses and quality losses in infected grain due to the accumulation of mycotoxins produced by the invading fungus. The objective of this study was to characterise the influence of different F. graminearum isolates and host resistance on FHB development and mycotoxin accumulation. A series of two greenhouse experiments were established where five single isolates of F. graminearum were tested. Three wheat cultivars were examined: Alsen (moderately resistant), 2375 (moderately susceptible) and Wheaton (susceptible). In the point-inoculation experiments, ca. 1000 conidia were placed into a central spikelet of spikes at anthesis. Point-inoculated spikelets were sampled at different growth stages up to soft dough stage. Samples from both experiment series were analysed for mycotoxins. The susceptible cultivar Wheaton had both the highest FHB severity and mycotoxin accumulation. The spread of symptoms both below and above the inoculated central spikelet was significantly higher in 2375 and Wheaton than Alsen. Though deoxynivalenol (DON) did not peak and decline in all experiments, when a peak in the DON content was present it was earlier in 2375 (early milk) than in either Alsen (early dough) or Wheaton (late milk). Though the isolates did not rank similarly in all experiments and in all cultivars, generally isolates Butte86Ada-11 and B63A were more aggressive and isolates 49-3 and B45A were less aggressive in terms of disease severity and mycotoxin accumulation.

scholarly journals Assessments of Fusarium Head Blight of Wheat and Barley in Response to Fungicide Treatment

Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 1021-1030 ◽  
Author(s):  
R. K. Jones
Keyword(s):  
Fusarium Head Blight ◽  
Host Response ◽  
Disease Incidence ◽  
Kernel Weight ◽  
Head Blight ◽  
Fungicide Treatment ◽  
Head Weight ◽  
Weight Test ◽  
Key Variables

Benomyl and tebuconazole reduced head blight incidence, head blight severity, and the percentage of visually scabby kernels (VSK) in harvested grain when applied to the susceptible spring wheat cv. Norm at anthesis. Deoxynivalenol (DON) concentration was also reduced. Fungicide treatment increased head weight, test weight, thousand kernel weight, and yield. Fludioxonil reduced certain parameters associated with the disease in barley, including incidence, severity, and deoxynivalenol concentration, while increasing the percentage of plump kernels and yield. In vitro, isolates of Fusarium graminearum were sensitive to fludioxonil, benomyl, tebuconazole, and mancozeb (concentrations that give 50% growth inhibition of 7.4 × 10-3, 3.5 × 10-1,9.9 × 10-1, and 7.3 mg a.i./liter, respectively). No evidence for insensitivity (resistance) was found. Prospects for chemical control of Fusarium head blight (FHB), however, remain limited. The repeatability of assessment methods used in evaluating host response to fungicides and to the damage caused by F. graminearum is discussed. Disease incidence, disease severity, VSK, and DON were identified as key variables that best measure the effects of FHB.

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