Project Summary: Plant disease is a limiting factor in agricultural production in Latin America. Plant pathogens cause losses estimated to be as high as $30 billion per year in the tropics alone. The risk of new introductions of Phytophthora species with trade requires continued monitoring and improved diagnostic capabilities. We have produced a platform of tools needed to detect, identify, and ultimately prevent the spread of species of Phytophthora (with a major focus on common and high threat species of Phytophthora) on horticultural crops from Central America. In this Immediate Impact Project, we deployed a series of diagnostic technologies to 23 diagnosticians from 9 countries at a Phytophthora diagnostics workshop held in San Jose Costa Rica in June 2010. These technologies included a protocols book, a computer based Lucid key to the species of Phytophthora, molecular and digital diagnostic identification systems to identify Phytophthora species and improve the diagnostic capabilities for important plant disease clinics in the region. Our work has had impact in the region and beyond as we trained a network of diagnosticians to survey Phytophthora diseases on horticultural crops and expanded the network into South America through the inclusion of participants from Peru and Chile. This workshop also built important connections and relationships as many of the participants had never met one another previously. We plan to continue a survey of Phytophthora species on horticultural crops in the region and link diagnosticians via a web‐based Latin American Phytophthora Diagnostic Network (LAPDN). These funds also allowed us to complete the “Key to the Common Phytophthora species” which will soon be available by the American Phytopathological Society Press (APS Press). We presented a poster and demonstration on the diagnostic tool at the APS meeting in Hawaii in August 2011 and expect the tool to be useful for plant disease clinics around the world.