Integrated Use of Tebuconazole and Fusarium Head Blight–Resistant Barley Genotypes

Abstract

All malting barley (Hordeum vulgare L.) cultivars adapted for production in the upper midwestern USA are susceptible to Fusarium head blight (FHB), incited primarily by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein)]. Quality of FHB‐infected barley is reduced due to a mycotoxin called deoxynivalenol (DON) that is produced by the pathogen. Malting barley buyers severely discount or refuse to purchase barley with DON concentrations >0.5 mg kg−1. Individually, use of genetic resistance or fungicides has not successfully reduced DON concentrations to acceptable limits. The objective of this research was to determine if the integrated use of the fungicide tebuconazole (α‐[2‐(4‐chlorophenyl) ethyl]‐α‐(1,1‐dimethylethyl)‐1H‐1,2,4‐triazole‐1‐ethanol) and barley genotypes with partial FHB resistance could reduce DON to acceptable concentrations. Field research, using two rates of tebuconazole (0 and 118 mL a.i. ha−1) and 13 barley genotypes with varying levels of FHB resistance, was conducted in North Dakota from 2000 to 2002. No supplemental inoculum or irrigation was used in any of the environments. Data for FHB severity, DON concentration, foliar disease severity, and kernel color were collected and analyzed. Deoxynivalenol was detected in all environments at concentrations >0.5 mg kg−1. Overall, the response of the FHB‐resistant and moderately resistant genotypes to tebuconazole was inconsistent for FHB severity and DON accumulation. Furthermore, tebuconazole applied to FHB‐resistant or moderately resistant genotype did not consistently result in DON concentration of ≤0.5 mg kg−1 in any of the environments. Thus, the integrated use of FHB‐resistant or moderately resistant genotypes and tebuconazole will not reduce DON.

Efficacy and Stability of Integrating Fungicide and Cultivar Resistance to Manage Fusarium Head Blight and Deoxynivalenol in Wheat

“…Although MS_UT generally had the lowest within-trial rank, there was a collection of environments (trial numbers 9,11,16,17,18,19,20,21,23,24,45, and 46, mostly from Maryland and Missouri) where S_TR had the lowest rank. Many of these trials also had large ranks for MR_UT (which, overall, had an intermediate rank).…”

“…In general, combining an appropriately timed fungicide application with a moderately resistant cultivar usually results in the greatest reductions in disease intensity and toxin accumulation (46). However, the reported efficacy of this approach in terms of percent reduction in FHB and DON has varied among individual integrated management trials (9,45,46). In addition, results from some trials have shown that, under certain conditions, cultivar resistance or fungicide treatment alone may provide levels of FHB and DON reduction comparable with that of the resistance-fungicide management combination (44,46).…”

Effect of harvest date on barley grain contamination with Fusarium spp. and deoxynivalenol in northeastern Ontario

“…The highest DON concentration observed in this study was 0.5 mg kg (McMullen et al 1997;Tekauz et al 2000). The disease reduces yield and results in poor seed quality, which has a negative impact on the market value of the grain and on seed vigour (Horsley et al 2006). In addition, the disease causes kernel contamination with mycotoxins, such as deoxynivalenol (DON) and nivalenol (Campbell et al 2002;Müeller et al 1997), which are harmful to humans and livestock.…”

“…Grain contamination with DON is a food and feed concern in many countries around the world (Campbell et al 2002;Placinta et al 1999). Furthermore, the malting and brewing industries reject grain with even minute amounts of DON because of quality issues with the resulting malt and beer (Beattie et al 1998;Horsley et al 2006).…”

Effects of Integrating Cultivar Resistance and Fungicide Application on Fusarium Head Blight and Deoxynivalenol in Winter Wheat

“…In contrast, Mesterhazy et al (13) found that fungicide efficacy in controlling FHB and DON accumulation was greater in more resistant than in more susceptible winter wheat cultivars. Horsley et al (6) applied tebuconazole to 13 barley genotypes with varying levels of FHB resistance. They found the response to tebuconazole of moderately resistant genotypes to be inconsistent for FHB severity and DON accumulation.…”