The long-term goal of this research is to develop management strategies for canker pathogens based on sound understandings of pathogen epidemiology across stone fruit orchards. Canker pathogens are difficult to manage because disease symptoms are hard to identify early in disease process, and trees produce a crop in initial phases of infection, and this delays growers' decisions about IPM treatments. Pathogens to spread and result in new economically destructive infections. In Colorado, Cytospora canker is the most damaging disease faced by fruit growers. Several Cytospora spp. are documented to cause disease on peach, apple and cherry, yet management for Cytospora occurs mainly in peach. The importance of host specificity and the role apple and cherry orchards play in the epidemiological cycle has not been demonstrated. The goals of this integrated research and extension CARE project are to: 1. Survey peach, cherry, and apple orchards in Colorado to estimate Cytospora spp. incidence and severity, 2. Delineate Cytospora species distribution in fruit orchards with molecular and morphological techniques and elucidate movement of Cytospora spp. within and among fruit orchards, 3. Perform pathogenicity assays to determine fruit crop host range of each Cytospora species, and 4. Develop conceptual scenarios to illustrate the importance of early implementation of best management practices to reduce Cytospora canker. The project will be completed in collaboration with the Cytospora Working Group and Tri Area Extension. Developing novel methods could revolutionize the sustainable management for canker pathogens in orchards which are an integral part of the culture and economy.