USWBSI Abstract Viewer

2023 National Fusarium Head Blight Forum


FHB Management (MGMT)

Invited Presenter

A Network Meta-Analysis of Results from Over a Quarter-Century of Uniform Fungicide Trials in the U.S.

Authors & Affiliations:

L.V. Madden1, W.B. Moraes1, and P.A. Paul1
1Ohio State University, Department of Plant Pathology, Wooster, Ohio
Corresponding author: Laurence V. Madden, madden.1@osu.edu

Corresponding Author:

Laurence Madden
madden.1@osu.edu

Abstract:

Early research by Marcia McMullen and colleagues starting in 1995 showed that a single application of a triazole (DMI) fungicide had the potential to reduce FHB index (field severity). This led to the establishment of the Uniform Fungicide Trials (UFTs) by the USWBSI, with field studies commencing in 1998. Early trials focused on propiconazole (trade name Tilt) and tebuconazole (Folicur). Metconazole (Caramba) was first tested in 2000, and tebuconazole+prothioconazole (Prosaro) in 2002. Starting in 2008, strobilurins were tested in the UFTs, and different application timings for DMIs were evaluated starting in 2009. A series of network meta-analyses of over 300 separate trials from 1995 through 2013 definitively showed the benefits of a well-timed single application of a DMI fungicide at or shortly after anthesis. Prosaro and Caramba were clearly more efficacious than other fungicides, with an average percent control (percentage reduction relative to the untreated check) of 48-54% for disease index and 37-44% for DON.  Results gave final verification that an application of a strobilurin-based fungicide between flag leaf stage and anthesis resulted in substantially higher levels of DON than the check, and thus should be avoided. Recommendations for management of FHB with fungicides were generally well established based on the results through 2013. However, with the registration of the new SDHI fungicide pydiflumetofen combined with the DMI propiconazole (Miravis Ace), there was the opportunity to reassess the best fungicide treatments for FHB. Based on a new network meta-analysis of 68 trials from 2018-2021, Miravis Ace applied at anthesis had higher mean percent control for index (~65%) and DON (~50%) than Prosaro or Caramba applied at anthesis or Miravis Ace applied around heading (~55% for index and ~30% for DON). A late application of Miravis Ace (4-6 days post-anthesis) was equally effective as an application at anthesis for DON control, but was not as effective for control of disease index. Treatments with two sequential fungicide applications had substantially greater percent control for index and DON. By pooling all UFTs from 2000-2021, stability of the efficacy of Caramba and Prosaro was also characterized. Using novel methods in network meta-analysis, heterogeneity of efficacy was characterized through empirical BLUPs, and time trends were represented with natural cubic splines. Although there were significant changes in percent control with Prosaro and Caramba over the years, there was no evidence of a loss of efficacy or change in sensitivity to the fungicides.  


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