2008 Annual Report 1a.Objectives (from AD-416) Optimize fungicide applications for control of Sclerotinia stem rot of canola. 1b.Approach (from AD-416) We will evaluate the role that three different plant population densities, row spacings, water volumes, two canopy heights, and nozzle configurations play in canopy penetration and target coverage by the fungicide spraying mixtures. 3.Progress Report This project was initiated on June 1, 2006, and research is ongoing. The overall objective is to develop and test novel field-based chemical control options for Sclerotinia stem rot (SSR) in canola. ADODR monitoring activities to evaluate research progress included phone calls, meetings with the cooperator, and an annual meeting held each year in January. Field experiments were installed at the Langdon, ND Research station in the summer of 2008. By the end of July 2008, some of the plots had been inoculated with ascospores produced in the laboratory while others were inoculated with ascospores produced by apothecia in the field. Data loggers placed within the canopy record soil moisture, relative humidity, leaf wetness and precipitation daily. Disease developed in all plots and data were collected by the end of August, but has not been analyzed yet. Sclerotial mats were buried in the upper inch of soil at four locations in North Dakota (Carrington, Fargo, Langdon, and Minot) during the summer of 2008. Soil temperature and moisture sensors were placed to the side of the mats. Sclerotia in the mats produced apothecia in Langdon but not in the other locations. The information generated by this study has been collected but not analyzed yet. This information along with data generated in growth chamber studies currently in progress will be used to develop a model that relates soil moisture and temperature to apothecia formation. The National Sclerotinia Initiative contributes to the goals of ARS National Program 303 – Plant Diseases.