Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/15/2004
Publication Date: 12/16/2004
Citation: Schisler, D.A., Zhang, S., Michael, B.J., Lipps, P.E. 2004. USDA-ARS, Ohio State University cooperative research on biological control of fusarium head blight 1: Use of diatomaceous earth as a carrier for formulations of the antagonist Cryptococcus nodaensis OH 182.9. National Fusarium Head Blight Forum Proceedings, December 11-15, Orlando, FL. p. 369-373.
Technical Abstract: Extensive field testing has demonstrated the efficacy of patented yeast Cryptococcus nodaensis OH 182.9 NRRL Y-30216) against Fusarium head blight (FHB) of wheat across a wide range of field environments. After discovery of this yeast, we developed optimized liquid culture, biomass production protocols and produced an efficacious frozen biomass concentrate. Because the development of a dried biocontrol product would have potential advantages of ease of handling, convenience in transportation, favorable economics and acceptance by consumers and commercial developers, studies were initiated to test a variety of diatomaceous earth (DE) formulants on the survival and efficacy of OH 182.9 after air-drying. For 6 different formulants, OH 182.9 CFU's on average were virtually unchanged over the course of 21 weeks of storage at 4 deg C (10.4 x 1010 to 11.5 x 1011 CFU/g). DE formulant MN 51 was selected for pilot plant-scale production of a dried OH 182.9 product. Field performance of this OH 182.9 DE product was variable across sites and wheat cultivars. Although disease level was relatively low in Peoria, IL, wheat cultivar Freedom treated with rehydrated cells of OH 182.9 in DE (MN 51) had significantly lower disease severity compared to the untreated check and was similar to the Folicur fungicide treatment. In Wooster, OH, where FHB severity was higher, the dried product did not reduce disease symptoms on either wheat cultivar tested, while freshly produced cells of OH 182.9 significantly reduced severity on cultivars Freedom and Elkhart by as much as 56% and performed statistically better and worse than Folicur on Freedom and Elkhart, respectively. Testing of rehydration activators and stickers should clarify the potential efficacy of dried DE formulations of OH 182.9.