2007 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 report documents research conducted under a specific cooperative agreement between ARS and North Dakota State University. Additional details of research can be found in the report for the in-house associated project 5442-21220-023-00D, “Sclerotinia Diseases.” 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 in canola. Three field trials were established at NDSU experimental stations in Langdon and Carrington. These trials evaluated the impact of using three different water volumes (10, 15, and 20 gallons per acre), two ground delivery methods (conventional and air-propelled sprayers) and three row spacings on control of Sclerotinia stem rot. These trials were artificially inoculated with ascospores that were sprayed at approximately 50% bloom. A misting system helped provide moisture for infection. Canopy coverage by the spraying mix was evaluated using water sensitive paper that was placed at the bottom of each experimental plot. The best coverage was provided by the higher water levels delivered using the air-propelled sprayer. However, in spite of operating a misting system, disease did not develop to measurable amounts due to the high temperature that prevailed during the flowering stage at both locations. These trials have been established in the summer of 2007. ADODR monitoring activities to evaluate research progress included phone calls, meetings with the cooperator, and an annual meeting held each year in January. Publications: Bradley, C. A., R. A. Henson, P. M. Porter, D. G. LeGare, L. E. del Río, and S. D. Khot. 2006. Response of canola cultivars to Sclerotinia sclerotiorum in controlled and field environments. Plant Dis. 90:215-219. del Río, L. E., C. A. Bradley, R. A. Henson, G. J. Endres, B. K. Hanson, K. McKay, M. Halvorson, P. M. Porter, D. G. LeGare, and H. A. Lamey. 2007. Impact of Sclerotinia stem rot on yield of canola. Plant Dis. 91:191-194. Harikrishnan, R. and L. E. del Río. 2006. Influence of temperature, relative humidity, ascospore concentration, and length of drying of colonized dry bean flowers on white mold development. Plant Dis. 90:946-950. Harikrishnan, R. and L. E. del Río. 2007. Influence of sand and moisture contents and sclerotial size on carpogenic germination of Sclerotinia sclerotiorum. (submitted to Plant Disease for publication in March 2007).