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Influence of Rainfall Patterns on the Development of Fusarium Head Blight, Accumulation of Deoxynivalenol and Fungicide Efficacy

Andersen, Kelsey F
http://rave.ohiolink.edu/etdc/view?acc_num=osu1385989033

Abstract Details

2013, Master of Science, Ohio State University, Plant Pathology.
Fusarium head blight (FHB) is a disease of wheat and other small grains primarily caused by the fungal pathogen Fusarium graminearum. It has been well established that moisture around anthesis is critical for FHB development and wheat grain contamination with deoxynivalenol (DON), a mycotoxin produced by F. graminearum. First, two field and two mist chamber experiments were conducted to quantify the effects of pre-anthesis rainfall and post-anthesis mist, respectively, on FHB index (IND) and DON. For both sets of experiments, four rainfall or mist treatments, one continuous and three intermittent, were applied during a 7- or -8 -day window before or after anthesis, plus an untreated check. Based on results from linear mixed model analyses, rainfall and mist treatment had significant effects on arcsine-transformed IND (arcIND) and log-transformed DON (logDON) in all experiments. The continuous 7- or 8-day moisture treatments consistently had the highest mean IND and DON levels, but several of the 4-day intermittent moisture treatments were not significantly different from the continuous moisture treatment. Mixed model regression analyses showed that there was a significant, positive relationship between IND and logDON in all experiments. Moisture treatment did not have a significant effect of the regression slopes (rate of logDON increase per unit increase in IND), but affected the intercepts in all cases. The height of the regression line (level of logDON at a fixed level of IND) was consistently higher for one of the intermittent rainfall/mist treatments (two days of mist or rainfall at the beginning and end of the treatment window) than the continuous moisture treatment. Generalized linear mixed models were used to estimate the risk of IND and DON exceeding critical thresholds, showing similar results in terms of estimated probabilities. Several of the intermittent treatments has comparable estimated probabilities of infection, IND > 10% and DON > 2, 5, and 10 ppm to the continuous rainfall and mist treatments. Second, Three field experiments were conducted during 2012 and 2013 in Wooster, Ohio. Simulated rainfall of a fixed intensity and duration was applied to separate plots at five different times after the fungicide treatment (0, 60, 105, 150, and 195 minutes). Spike samples were collected at 4-day intervals after fungicide application and assayed for tebuconazole residue. A similar set of greenhouse experiments were conducted using six post-fungicide-application rainfall timing treatments (0, 15, 30, 60, 120, and 180 minutes). All experiments were inoculated at anthesis with spores of F. graminearum, and FHB index (IND) and DON were quantified. In four of the five experiments, all fungicide-treated experimental units (EUs) had significantly lower mean IND and DON than the untreated check, regardless of rainfall treatment. Among rainfall treatments, EUs that received the earliest rains tended to have the highest mean IND and DON, but were generally not significantly different from EUs that received later rain or fungicide without rain. In both years, fungicide residue on wheat spikes decreased rapidly with time after application, but the rate of reduction varied between years. Rainfall treatment did not have a significant effect on the rate of residue reduction or the level of residue at a fixed sampling time after fungicide application. In this study, 19% tebuconazole + 19% prothioconazole was fairly rainfast for a fixed set of rainfall characteristics, and tebuconazole residue did not persist very long after application on wheat spikes.
Pierce Paul (Advisor)
Anne Dorrance (Committee Member)
Laurence Madden (Committee Member)
Clay Sneller (Committee Member)
136 p.
Plant Pathology
Fusarium graminearum, Gibberella zeae, triazole

Recommended Citations

Citations

  • Andersen, K. F. (2013). Influence of Rainfall Patterns on the Development of Fusarium Head Blight, Accumulation of Deoxynivalenol and Fungicide Efficacy [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385989033

    APA Style (7th edition)

  • Andersen, Kelsey. Influence of Rainfall Patterns on the Development of Fusarium Head Blight, Accumulation of Deoxynivalenol and Fungicide Efficacy. 2013. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1385989033.

    MLA Style (8th edition)

  • Andersen, Kelsey. "Influence of Rainfall Patterns on the Development of Fusarium Head Blight, Accumulation of Deoxynivalenol and Fungicide Efficacy." Master's thesis, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385989033

    Chicago Manual of Style (17th edition)

osu1385989033
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This open access ETD is published by The Ohio State University and OhioLINK.