** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** MOVEMENT OF PATHOGENS BETWEEN ECOSYSTEMS IS A MAJOR DRIVER OF PATHOGEN EMERGENCE IN HUMANS, ANIMALS, AGRICULTURAL CROPS, AND NATURAL ECOSYSTEMS. INVASIVE PLANTS SPAN NATURAL, DISTURBED, AND AGRICULTURAL SYSTEMS, PROVIDE A NOVEL, ABUNDANT HOSTFOR NOVEL GROUPS OF MICROBES, AND CAN HAVE AN OUTSIZED ROLE IN PATHOGEN TRANSMISSION BECAUSE INVASIVE PLANTS OCCUR IN HIGH DENSITY AND CREATE CONDUCIVE ENVIRONMENTS FOR DISEASE. THIS RESEARCH WILL EXAMINE THE ROLE OF INVASIVE PLANTS IN THE ECO-EVOLUTIONARY DYNAMICS OF TRANSMISSION ACROSS ECOSYSTEMS BOUNDARIES AND CROP DISEASE EMERGENCE, AND CAPTURE INITIAL EPIDEMIC DYNAMICS OF AN EMERGING PATHOGEN ON A NOVEL HOST IN REAL TIME. THE SHARP CONTRASTS BETWEEN AGRICULTURAL AND WILD HOSTS IN SPATIAL AND COMMUNITY STRUCTURE, PHENOLOGY, INDIVIDUAL HETEROGENEITY, AND MICROBIOMES PROVIDE AN IDEAL MODEL SYSTEM FOR EMPIRICAL AND THEORETICAL INVESTIGATION OF THE INTERPLAY OF THESE FACTORS ON ECOLOGICAL AND EVOLUTIONARY DYNAMICS OF INFECTIOUS DISEASES AT AND ACROSS ECOSYSTEM BOUNDARIES. OUR RESULTS WILL ADVANCE UNDERSTANDING OF ECOLOGICAL AND EVOLUTIONARY DRIVERS OF PATHOGEN SPILLOVER AND ADAPTATION TO A NOVEL HOST, INFORM MORE GENERAL THEORY IN INFECTIOUS DISEASE ECOLOGY, AND ULTIMATELY IMPROVE PREDICTION AND MANAGEMENT OF EMERGING DISEASES.