Project Number: 3620-22410-011-04
Project Type: Trust

Start Date: Aug 04, 2008
End Date: Dec 31, 2008

Objective:
(1) Determine the efficacy of fungicide-tolerant variants of yeast Cryptococcus flavescens NRRL Y-30216 (developed in previous research conducted at NCAUR, USDA-ARS) in reducing FHB in greenhouse trials; (2) determine compatibility of wild-type OH 182.9 and fungicide-tolerant variants with essential oil surfactants; and (3) field test the most effective fungicide-tolerant variant(s), wild-type OH 182.9, best surfactant, and fungicide in various combinations in a field trial to be conducted at OSU¿s Ohio Agricultural Research and Development Center in Wooster, OH.

Approach:
Established methods for submerged, liquid culture fermentation of C. flavescens will be utilized to produce wild-type and fungicide-tolerant variants of OH 182.9. Fungicide-tolerant variants will be compared for identity with wild-type OH 182.9 using Biolog microplate typing and other biochemical and physiological tests of taxonomic utility as needed. After confirmation of variant identity with the wild-type, fungicide-tolerant variants will be bioassayed on wheat plants for efficacy in reducing FHB. Wild-type and fungicide-tolerant variants of OH 182.9 will be combined with the fungicide and used to treat wheat plants in greenhouse tests to determine what levels of fungicide, if any, result in greater levels of FHB control than found with antagonist or fungicide use alone. Plants will be scored for disease incidence, severity and 100 kernel weights as determinants of treatment efficacy. Concurrently, the compatibility of wild-type OH 182.9 and fungicide-tolerant variants with essential oils that could be useful as surfactants in formulations of OH 182.9 and/or fungicide-tolerant variants will be tested. A field test of the most effective fungicide-tolerant variant(s), wild-type OH 182.9, essential oil surfactant, and fungicide in various combinations will be conducted at OSU's Ohio Agricultural Research and Development Center in Wooster, OH, using the essential oil decided on by MOI and microbial biomass supplied by ARS.