PLANT PATHOGENS TRANSMITTED BY ARTHROPODS HAVE DEVASTATING EFFECTS ON CROP YIELD AND QUALITY IN MANY AGROECOSYSTEMS. IN THE PACIFIC NORTHWEST (PNW) US, POTATO PSYLLIDS (BACTERICERA COCKERELLI) VECTOR A BACTERIAL PATHOGEN, CANDIDATUS LIBERIBACTER SOLANACEARUM ("CLSO") THAT CAUSES SEVERE YIELD LOSSES IN POTATO CROPS AND MAKES TUBERS UNMARKETABLE. MANAGEMENT OF POTATO PSYLLID AND CLSO IS EXTREMELY CHALLENGING BECAUSE PSYLLIDS ARE GENERALISTS THAT USE MULTIPLE CROP AND NON-CROP HOSTS; WEEDY HOSTS ACT AS SOURCES OF PSYLLIDS AND LSO INTO POTATO FIELDS. HOWEVER, THE ENVIRONMENTAL TRIGGERS THAT MEDIATE MOVEMENT BETWEEN THESE CROP AND NON-CROP HOSTS REMAIN LARGELY UNKNOWN. OUR PROJECT WILL ADDRESS THIS KNOWLEDGE GAP BY COMPLETING TWO COMPLEMENTARY OBJECTIVES THAT WILL EXPLORE HOW ENVIRONMENTAL STRESS AND HOST IDENTITY AFFECTS (1) PSYLLID HOST USE AND MOVEMENT; AND (2) ACQUISITION AND TRANSMISSION OF CLSO. OUR RESEARCH WILL BE CONDUCTED IN COLLABORATION WITH A NETWORK OF COOPERATING POTATO GROWERS IN THE PNW TO FACILITATE THESE GOALS. OUR PROJECT ADDRESSES TWO AFRI FARM BILL PRIORITY AREAS: PLANT HEALTH AND PRODUCTION AND BIOENERGY, NATURAL RESOURCES, AND ENVIRONMENT BY INCREASING OUR UNDERSTANDING OF THE ROLE OF NON-CROP HOST PLANTS AND ENVIRONMENTAL STRESSORS ON MEDIATING THE DYNAMICS OF A VECTOR AND VECTOR-BORNE PATHOGEN, WHICH WILL HAVE BROAD APPLICABILITY TO MANY AGROECOSYSTEMS.