|Boehm, Michael -|
|Paul, Pierce -|
Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 5, 2009
Publication Date: August 10, 2009
Citation: Schisler, D.A., Boehm, M.J., Paul, P.P. 2009. Variants of Antagonist Cryptococcus flavescens OH 182.9 with Improved Efficacy in Reducing Fusarium Head Blight in Greenhouse and Field Environments. Phytopathology 99:S115. Technical Abstract: The inclusion of biological control agent Cryptococcus flavescens OH 182.9 in the integrated management of Fusarium head blight (FHB) has potential for significantly contributing to the reduction of FHB and deoxynivalenol (DON) in wheat. Experiments were conducted to determine if liquid culture growth conditions could be modified to promote the production of stable variants of OH 182.9 with improved efficacy compared to the wild type progenitor strain. A protracted exposure of OH 182.9 to conditions adverse to cell growth resulted in the isolation of variants OH 182.9 3C and OH 182.9 4C. In greenhouse tests, variant 4C reduced head blight severity by 83% compared to 36% for the wild type (WT) strain. In two field trials on susceptible winter wheat, variants 3C and 4C reduced severity by 34% and 42% compared to the control (P<0.05, Bonferroni) in one trial and 21% and 24% in another (NSD) while the WT strain had no consistent effect. For both field trials, treating flowering wheat heads with the fungicide Proline® and variant 3C after 24 hours was the most successful treatment in reducing FHB severity (control vs. treated averages of 10.0% vs. 1.4%, respectively) and DON (10.0 vs 2.3 ppm, respectively). Similar trends, though to a lesser degree, were observed in field trials on a moderately FHB-resistant winter wheat. Enhanced efficacy variants of antagonist OH 182.9 warrant further study regarding their inclusion in the integrated management of FHB.