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Poster: Biology & Disease Mgmt: Chemical Control


Management of Fusarium Head Blight and DON in Alabama
K. BOWEN (1), N. Sharma (1), N. McMaster (2), J. Jones (3), M. Pegues (3) (1) Auburn University, U.S.A.; (2) Virginia Tech, U.S.A.; (3) Alabama Agricultural Experiment Station, U.S.A.

Fusarium head blight of wheat (FHB), caused by Fusarium graminearum, was severe on winter wheat in southern Alabama in the spring of 2015. A fungicide trial with four replications, planted to ‘AGS 2060’, allowed evaluations of demethylation inhibitor (DMI) and DMI plus quinone outside inhibitor (QoI) fungicides for managing FHB and the mycotoxin, deoxynivalenol (DON). Fungicides were applied at Feekes stage 10.5 (inflorescence complete). FHB intensity across plots was rated on a scale of 0 to 9 on 27 Apr, where 0=no disease and 9=severe disease. Plots were machine-harvested 5 Jun and kernel samples assayed for DON content. FHB in non-treated plots was rated at 7.2, which was significantly greater than FHB intensity in plots treated with propiconazole (Prop), tebuconazole (Tebu) plus trifloxystrobin (Trif), or Tebu plus prothioconazole (Proth), while Trif+Proth and metaconazole (Metc) plus pyraclostrobin (Pyra) had intermediate FHB levels. DON concentration, however, was > 5 ppm in grain samples from Trif+Proth- and Metc+Pyra-treated plots; only grain from Tebu+Proth-treated plots had lower DON concentrations, at 3.1 ppm, than from non-treated plots (4.6 ppm). Yield and test weight were low due to heavy disease pressure and lodging, and did not differ due to fungicide. These results confirm that a QoI fungicide, even when applied in combination with a DMI, can increase DON concentration under severe FHB pressure in wheat.