scholarly journals Disease Risk, Spatial Patterns, and Incidence-Severity Relationships of Fusarium Head Blight in No-till Spring Wheat Following Maize or Soybean

Plant Disease ◽  
2015 ◽  
Vol 99 (10) ◽  
pp. 1360-1366 ◽  
Author(s):  
Pierri Spolti ◽  
Denis A. Shah ◽  
José Maurício C. Fernandes ◽  
Gary C. Bergstrom ◽  
Emerson M. Del Ponte
Keyword(s):  
Fusarium Head Blight ◽  
Large Scale ◽  
Disease Risk ◽  
Random Pattern ◽  
Southern Brazil ◽  
Head Blight ◽  
Previous Crop ◽  
Regional Sources ◽  
Epidemiological Surveys ◽  
The Relationship

The first large-scale survey of Fusarium head blight (FHB) in commercial wheat fields in southern Brazil was conducted over three years (2009 to 2011). The objectives were to: (i) evaluate whether increased FHB risk is associated with within-field maize residue; (ii) determine the spatial pattern of FHB incidence; and (iii) quantify the relationship between FHB incidence and severity. FHB was assessed in a total of 160 fields between early milk and dough. Incidence ranged from 1.0 to 89.9% (median = 25%) and severity from 0.02 to 18.6% (median = 1.3%). FHB risk was neither lower nor higher in wheat following maize than in wheat following soybean. Only 18% of fields were classified as having aggregated patterns of FHB-symptomatic spikes. A binary power law description of the variances was consistent with an overall random pattern of the disease. These results conform with the hypothesis that FHB epidemics in southern Brazil are driven by sufficient atmospherically-transported inoculum from regional sources. The incidence-severity relationship was coherent across growing season, growth stage, and previous crop; one common fitted curve described the relationship across all observations. Estimating severity from incidence may be useful in reducing the workload in epidemiological surveys.

scholarly journals Meso- and Microscale Patterns of Fusarium Head Blight in Spring Wheat Fields in Minnesota

Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 474-479 ◽  
Author(s):  
K. P. Wilhelm ◽  
R. K. Jones
Keyword(s):  
Spatial Distribution ◽  
Fusarium Head Blight ◽  
Spring Wheat ◽  
Disease Incidence ◽  
Optimal Number ◽  
Random Pattern ◽  
Head Blight ◽  
Frequency Distributions ◽  
Previous Crop ◽  
Regional Disease

Several techniques were used to study the spatial distribution of Fusarium head blight (FHB) in spring wheat fields in the Red River Valley of Minnesota in 2001 and 2002. Four scales of study were analyzed, ranging from countywide comparisons down to adjacent heads. Agreement to frequency distributions and the departure from randomness, along with the autocorrelation of FHB clusters, were calculated at each scale. Regression analysis also was used to describe any edge affects that might exist. Finally, the optimal number of samples to adequately assess a 32.4-ha (80-acre) field was determined to a precision of ±5% disease incidence (DI). The analysis showed that DI had a random pattern at scales smaller than 32.4-ha fields, including quadrats of 6,561, 729, and 9 m2, as well 0.8-m transects involving consecutive heads within drill rows. There was no difference in DI associated with edges of fields compared with the incidence of FHB in transects within fields. Analysis of the spatial distribution at the mesoscale (county and township) showed no association in FHB DI between fields based on proximity. Differences were attributed to previous crop and in-field residue. Disease incidence was most accurately assessed on a field-by-field basis. The optimal sampling size (with <5% error) for surveying for the incidence of FHB in a standard commercial field was seven 20-head samples. Regional disease estimates would improve from including more fields at the expense of fewer samples per field.

Quantification of the relationship between the environment and Fusarium head blight, Fusarium pathogen density, and mycotoxins in winter wheat in Europe

2012 ◽  
Vol 133 (4) ◽  
pp. 975-993 ◽  
Author(s):  
Alissa B. Kriss ◽  
Pierce A. Paul ◽  
Xiangming Xu ◽  
Paul Nicholson ◽  
Fiona M. Doohan ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Fusarium Head Blight ◽  
Head Blight ◽  
The Relationship

scholarly journals Deoxynivalenol and nivalenol in commercial wheat grain related to Fusarium head blight epidemics in southern Brazil

2012 ◽  
Vol 132 (2) ◽  
pp. 1087-1091 ◽  
Author(s):  
Emerson M. Del Ponte ◽  
Jaqueline Garda-Buffon ◽  
Eliana Badiale-Furlong
Keyword(s):  
Fusarium Head Blight ◽  
Southern Brazil ◽  
Wheat Grain ◽  
Head Blight

scholarly journals Variation Among Isolates of Fusarium graminearum Associated with Fusarium Head Blight in North Carolina

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 404-410 ◽  
Author(s):  
Scott L. Walker ◽  
Steven Leath ◽  
Winston M. Hagler ◽  
J. Paul Murphy
Keyword(s):  
North Carolina ◽  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Phenotypic Diversity ◽  
In Vitro Growth ◽  
Head Blight ◽  
Potential Threat ◽  
Previous Crop

Fusarium head blight (FHB) can reduce yield of wheat and decrease the value of harvested grain by accumulation of detrimental toxins. Understanding the variability of the fungal population associated with infection could improve disease control strategies. Sixty-six isolates of Fusarium graminearum associated with FHB were collected in North Carolina and tested for in vitro growth rate, in vitro production of deoxynivalenol (DON) and zearalenone, and pathogenicity on three cultivars of soft red winter wheat. Significant differences among isolates were found for all three traits. Randomly Amplified Polymorphic DNA (RAPD) analysis revealed high levels of genotypic diversity among isolates. Isolates of F. graminearum, F. culmorum, and F. avenaceum acquired from the Pennsylvania State University Fusarium Center were included for comparison in all tests. In vivo levels of DON were measured for the five isolates associated with the highest levels of disease and the five isolates associated with the lowest levels of disease, and no significant differences were found. However, all ten isolates produced detectable levels of DON in vivo. Mean disease ratings ranged from 3.4 to 96.4%, in vitro (DON) levels ranged from 0 to 7176.2 ppm, and zearalenone ranged from 0 to 354.7 ppm, among isolates. A multiple regression model using in vitro growth, in vitro DON, and zearalenone production, collection location, wheat cultivar of isolate origin, plot, tillage conditions, and previous crop as independent variables and percent blighted tissue as the dependent variable was developed. The cumulative R2 value for the model equaled 0.27 with in vitro rate of growth making the largest contribution. Analysis of phenotype and genotype among isolates demonstrated diversity in a single plot, in a single location, and in North Carolina. Genotypic and phenotypic diversity were significant under both conventional and reduced tillage conditions, and diversity was high regardless of whether the previous crop had been a host or non-host for F. graminearum. These data indicate a variable pathogen population of F. graminearum exists in North Carolina, and members of this population can be both highly pathogenic on wheat and produce high levels of detrimental toxins, indicating a potential threat for problems with FHB within the state.

scholarly journals The Effect of Previous Crop Residues and Tillage on Fusarium Head Blight of Wheat

Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 71-76 ◽  
Author(s):  
R. Dill-Macky ◽  
R. K. Jones
Keyword(s):  
Fusarium Head Blight ◽  
Crop Residues ◽  
Cultural Practices ◽  
Conservation Tillage ◽  
Head Blight ◽  
Tillage Practices ◽  
Previous Crop ◽  
No Till ◽  
Chisel Plow ◽  
Spring Wheat Cultivar

Effects of previous crop residues and tillage practices on Fusarium head blight (FHB) of wheat were examined. Fusarium head blight was monitored in plots of the FHB-susceptible spring wheat cultivar Norm following crops of corn, wheat, and soybeans in 1995, 1996, and 1997. Moldboard plow, chisel plow, and no-till treatments were imposed perpendicular to crop strips to establish a range of residue levels in each of the previous crop residues. Fusarium head blight incidence and severity were greatest when wheat followed corn and least when wheat followed soybeans. Incidence and severity were lower in moldboard plowed plots than in either chisel plowed or no-till plots, although differences among chisel plow and no-till treatments were not apparent. Yields of wheat were approximately 15% lower in plots where wheat followed corn or wheat than in wheat following soybeans and were 10% greater in moldboard plowed plots than in either chisel plowed or no-till treatments. The deoxynivalenol (DON) content of harvested grain was significantly correlated with FHB incidence and severity. The DON level in wheat following soybeans, averaged across tillage treatments, was 25% lower than in wheat following wheat and 50% of the level in wheat following corn. These findings suggest that changes in regional tillage practices, principally the move toward conservation tillage and reduced-till systems, contributed to the recent FHB epidemics in the Upper Midwest. Because differences in the type and quantity of crop residues in small plots affected disease development, it is likely that local sources of inoculum, such as those within a grower's field, contribute directly to the inoculum load and disease potential. The implication of these findings is that selection of cultural practices aimed to reduce inoculum-borne residues will assist in the control of FHB.

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