Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 2007
Publication Date: July 26, 2008
Citation: Schisler, D.A., Slininger, P.J., Boehm, M.J. 2008. Development of co-cultivated mixtures of antagonists active against Fusarium head blight of wheat [abstract]. American Phytopathological Society Abstracts. p. 97:S104. Technical Abstract: Multistrain mixtures of biocontrol agents can foster greater and more consistent reductions of plant disease. Several different mixtures of Agricultural Research Service/Ohio State University-discovered antagonists reduced Fusarium head blight (FHB) in field studies. Microbial mixtures commonly are produced by blending separately produced fermentation products but co-cultivation of strains to equivalent biomass yields in a single fermentation would provide mixture advantages without incurring the cost disadvantages of multiple fermentation and processing protocols. To determine the feasibility and efficacy of co-cultured fermentor products, three strains of Cryptococcus spp. were grown in bi- and tripartite fermentations. Growth rate inequalities between co-cultured strains were overcome via establishing consistent initial culture optical densities using weighted ratios of each component strain. Growth curves of each component were determined by plating on a melezitose-based medium that produced colonies of individually distinguishable sizes. After 48 hours, co-cultures of Cryptococcus flavescens OH 182.9 and Cryptococcus aureus OH 71.4 had near equivalent cell counts that in preliminary trials reduced FHB disease severity by as much as 54 percent compared to 40 percent and no effect, respectively, for OH 182.9 and OH 71.4 tested separately in greenhouse studies. Further evaluation of co-cultured biocontrol products is justified.