2006 Annual Report 4d.Progress report. This report serves to document research conducted under a specific cooperative agreement between ARS and Oregon State University. Additional details of research can be found in the report for the parent project 5358-22000-030-00D, Biology and Control of Foliar and Fruit Diseases of Horticultural Crops. Dr. Kenneth Johnson and collaborators conducted the following research towards the agreements objectives: Fall 2005: A successful fungicide trial in Evergreen blackberry identified fungicide materials with activity against Phragmidium violaceum. Winter 2006: Based on Fall 2005 data, a 24C special local need registration was requested and obtained to allow for use of a 5 oz. per acre rate of myclobutanil for blackberry rust suppression. Spring 2006: Phenology of teliospore germination was determined and compared to similar data from Montpelier, France. A rotational trap study was initiated and completed at two locations in western Oregon. These two studies provide information on. 1)the window for when teliospores are likely to germinate, and. 2)within that window, the field conditions that lead to initial infection by the pathogen. These results compliment Dr. Mahafee’s research to model the effect of environment on infection by P. violaceum Spring/summer 2006: Fields experiments were initiated at two locations in western Oregon to evaluate appropriate timing and application intervals of fungicides. These trials are ongoing. Summer 2006: We are currently studying the effect of lime sulfur on teliospore viability. Field data from spring 2006 suggested that lime sulfur applied as a delayed dormant treatment effectively destroyed overwintering teliospores.