2008 Annual Report 1a.Objectives (from AD-416) Optimize multiple treatment factors to enhance biocontrol of Fusarium Head Blight. 1b.Approach (from AD-416) Optimize biocontrol of wheat scab incited by Gibberella zea (anamorph, Fusarium graminearum) as follows. Using greenhouse and field plant bioassays, evaluate the effects on biocontrol efficacy of multiplexing applications of superior biocontrol agents of scab of wheat that were discovered in previous cooperative research between ARS and The Ohio State University. Determine the feasibility of combining biocontrol agents with top fungicides, UV protectants, and resistant cultivars to acquire additive or synergistic levels of scab disease control. Improve bioreactor liquid culture media and incubation conditions to increase the quantity, efficacy, and amenability to formulation and shelf-life of biocontrol agent biomass produced. Through the use of molecular and bioassay techniques, determine the molecular basis of enhanced stress tolerance of biocontrol strains improved through production and selection techniques. 3.Progress Report A research priority of both The Ohio State University and the Agricultural Research Service is to develop new pest management technologies that reduce our dependence on chemical pesticides. Microorganisms naturally present in agricultural ecosystems have the potential to be utilized as environmentally compatible alternatives for controlling disease or as supplements to reduce levels of traditional chemicals. Our specific collaborative research interest is biocontrol of Fusarium head blight (FHB). Considerable research effort by private, government, and university research laboratories in this country and around the world demonstrates that no one control measure from among pesticides, biological control, cultural control, disease forecasting, and the use of resistant varieties is likely to be single-handedly consistent in reducing FHB to economically acceptable levels. Because the chemical prothioconazole recently has been approved for field use against FHB on wheat, the potential of combining this fungicide with a yeast biocontrol agent was studied on several levels. Research concentrated first on selecting for naturally occurring prothioconazole-tolerant variants of a yeast antagonist of FHB, Cryptococcus flavescens OH 182.9, grown in liquid medium containing sublethal concentrations of the fungicide. Putative fungicide-tolerant variants were then characterized for growth habit in liquid culture as compared to the progenitor antagonist strain. Tolerant strains with similar growth habit to the wild-type were tested in greenhouse bioassays and determined to be identical to the wild-type strain in efficacy reducing FHB in greenhouse trials and more effective than the wild-type when combined with the fungicide prothioconazole at label rates. Results of field trials conducted in Peoria, Illinois, and Wooster, Ohio, generally confirmed these trends and supported the concept of enhancing the level of FHB reduction on wheat by combining the pest management tools of fungicides and biocontrol agents. Monitoring activities took place within this project in the form of telephone calls and emails on at least a monthly basis. Personal visits with the collaborator took place two times in the last year when field trials were established and later monitored at the Wooster, OH, field facilities of the collaborator. In all types of communication, research plans, progress, and results were discussed and formal and informal reports exchanged as appropriate. This research is conducted under NP 303, Component 4, Problem Statement 4a and Problem Statement 4c.