** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** BUMBLE BEES ARE IMPORTANT NATIVE POLLINATORS OF BOTH WILD AND AGRICULTURAL PLANTS AND ARE COMMONLY MANAGED FOR THEIR POLLINATION SERVICES. MOST BUMBLE BEES MANAGED IN NORTH AMERICA ARE USED TO POLLINATE TOMATOES IN GREENHOUSES. GREENHOUSE-GROWN CROPS ARE AN IMPORTANT ELEMENT OF THE NATIONAL FOOD SUPPLY, PROVIDING YEAR-ROUND PRODUCTION OF ECONOMICALLY VALUABLE CROPS. THE 2019 UNITED STATES DEPARTMENT OF AGRICULTURE CENSUS OF HORTICULTURE SPECIALTIES REPORTED A NATIONAL PROFIT OF AROUND $703 MILLION FOR CROPS GROWN IN GREENHOUSES, 49% OF WHICH WAS FROM TOMATOES ($345 MILLION). NINETY FIVE PERCENT OF COMMERCIAL BUMBLE BEE COLONIES ARE EMPLOYED IN TOMATO GREENHOUSES, AND SO THERE ARE CLEAR ECONOMIC INCENTIVES TO SECURE THE CONTINUED SUCCESS OF THEIR POLLINATION SERVICES. HOWEVER, ENVIRONMENTAL FACTORS WITHIN GREENHOUSES MAY LIMIT MAXIMUM POLLINATION POTENTIAL. IN PARTICULAR, HEAVY FUNGICIDE USE MAY HAVE STRONG EFFECTS ON BUMBLE BEE POLLINATION AND COLONY LONGEVITY IN THE GREENHOUSE. THERE IS EVIDENCE IN BOTH THE LITERATURE AND IN MY PRELIMINARY WORK THAT SUGGESTS FUNGICIDE EXPOSURE IS A STRONG PREDICTOR OF DECREASED POLLINATION ACTIVITY AND COLONY HEALTH. THERE IS ALSO EVIDENCE THAT COMMERCIAL BUMBLE BEES HAVE HIGH RATES OF PATHOGEN INFECTION, WITH POTENTIAL PATHOGEN SPILLOVER INTO WILD POPULATIONS. IT IS UNCLEAR HOW THE COMBINED EFFECTS OF FUNGICIDE EXPOSURE COUPLED WITH COMMON PARASITE INFECTION IMPACTS BUMBLE BEE FORAGING BEHAVIOR AND POLLINATION SERVICES.I PROPOSE TO INVESTIGATE THE SEPARATE AND SYNERGISTIC EFFECTS OF FUNGICIDE EXPOSURE AND INFECTION OF THE GUT PARASITE CRITHIDIA BOMBI ON THE POLLINATION EFFICIENCY OF THE COMMON EASTERN BUMBLE BEE (BOMBUS IMPATIENS). I WILL COMPLETE THIS WORK BY (1) CONTINUING TO MONITOR BUMBLE BEE POLLINATION BEHAVIOR IN A COMMERCIAL TOMATO GREENHOUSE, AND (2) EXPERIMENTALLY TEST THE EFFECTS OF FUNGICIDE AND GUT PARASITES ON BUMBLE BEE FORAGING IN CONTROLLED OUTDOOR FLIGHT CAGES.THIS WORK WILL PROVIDE ESSENTIAL INFORMATION IN OUR UNDERSTANDING OF BUMBLE BEE POLLINATION OF TOMATOES AND SHED LIGHT ON THE EFFECTS OF COMMON BUMBLE BEE STRESSORS ENCOUNTERED IN GREENHOUSE SYSTEMS. ESTABLISHING A CAUSAL LINK BETWEEN FUNGICIDES AND BUMBLE BEE POLLINATION HAS HISTORICALLY BEEN DIFFICULT TO ESTABLISH BECAUSE OF CONFOUNDING FACTORS PRESENT IN LANDSCAPE STUDIES. GREENHOUSES OFFER AN UNIQUE OPPORTUNITY TO ADDRESS THIS QUESTION, AND LESSONS LEARNED HEREIN CAN GENERATE TESTABLE HYPOTHESES FOR FIELD SYSTEMS WITH WILD POLLINATORS. AN UNDERSTANDING OF FUNGICIDE'S IMPACTS ON BUMBLE BEE HEALTH IS OF HIGH IMPORTANCE BECAUSE BUMBLE BEES ARE EXPERIENCING DECLINES ON THE GLOBAL SCALE. BOTH FUNGICIDE EXPOSURE AND GUT-PATHOGEN INFECTION ARE NOT THOUGHT TO DIRECTLY CONTRIBUTE TO MORTALITY IN BUMBLE BEES, HOWEVER THEY EACH HAVE NOTABLE SUBLETHAL CONSEQUENCES. MY PROPOSED WORK WILL CONTRIBUTE ESSENTIAL PIECES TO THE PUZZLE OF THE CONSERVATION OF BUMBLE BEES AND THE VITAL ECOSYSTEM SERVICES THEY PROVE.I WILL PRESENT THE FINDINGS FROM THI,S RESEARCH AT PROFESSIONAL CONFERENCES, INCLUDING THE ENTOMOLOGICAL SOCIETY OF AMERICA, AND THE ECOLOGICAL SOCIETY OF AMERICA. I WILL ALSO PRESENT THE RESULTS OF MY FINDINGS AT THE CONTROLLED ENVIRONMENT AGRICULTURE RESEARCH CENTER (CEARC) ANNUAL CONFERENCE. I WILL PUBLISH MY RESULTS IN PEER REVIEWED JOURNALS, AND I WILL CREATE FACT SHEETS TO BE PUBLISHED WITH OSU'S EXTENSION OFFICE DETAILING MY FINDINGS AND TO BE EASILY SHARED WITH GROWERS AND OTHER STAKEHOLDERS IN THE INDUSTRY. THE RESULTS OF THIS STUDY CAN INFORM MANAGEMENT DECISIONS IN CONTROLLED ENVIRONMENT AGRICULTURE AND POTENTIALLY EXTEND TO THE USE OF FUNGICIDES IN AGRICULTURAL AND URBAN SETTINGS.