GLOBALLY APPROXIMATELY 16% OF CROPS ARE LOST A YEAR DUE TO DISEASE CAUSED BY PATHOGENS. IN ORDER TO SPREAD, PLANT PATHOGENS CAN MANIPULATE CHEMICAL SIGNALS EMITTED FROM THEIR HOSTS TO ATTRACT POTENTIAL VECTORS. POLLINATOR INSECTS RELY HEAVILY ON THESE CHEMICAL CUES, SUCH AS ODORS, WHEN SELECTING WHICH PLANTS TO VISIT AND THERE IS EVIDENCE THAT POLLINATORS CAN CONTRIBUTE TO PATHOGEN SPREAD IN AGRICULTURAL SYSTEMS. POLLINATION IS WIDELY USED IN AGRICULTURAL SYSTEMS AND EVEN CROPS THAT ARE NOT COMMERCIALLY SUPPLIED WITH POLLINATORS ARE OFTEN EXPOSED TO SOME LEVEL OF NATURALLY OCCURRING POLLINATION. HOWEVER, LITTLE IS KNOWN ABOUT THE EFFECTS OF PATHOGENS ON POLLINATOR BEHAVIOR OR THE ROLE OF POLLINATORS IN PATHOGEN TRANSMISSION IN AGRICULTURAL SYSTEMS. THE PURPOSE OF THIS PROPOSAL IS TO EXAMINE THE EFFECT OF PATHOGEN INFECTION ON PLANT CHEMICAL CUES AND THE ASSOCIATED EFFECTS ON POLLINATOR BEHAVIOR. THIS PROPOSAL WILL FOCUS ON ERWINIA AMYLOVORA, A WIDELY SPREAD PATHOGEN THAT CAUSES FIRE BLIGHT DISEASE IN ROSACEOUS PLANTS (I.E. APPLE AND PEAR). EFFECTS OF ERWINIA ACROSS PLANT SPECIES WILL BE EXPERIMENTALLY TESTED USING A SYNTHETIC NECTAR REPRESENTATIVE OF ROSACEOUS PLANTS TO EXAMINE EFFECTS OF INFECTION ON NECTAR CHEMISTRY AND VOLATILES. ADDITIONALLY, THE ABILITY OF POLLINATORS TO DETECT INFECTED NECTAR (NEUROPHYSIOLOGICAL RESPONSES) AND ASSOCIATED BEHAVIORAL RESPONSES WILL BE EXAMINED. PATHOGEN EFFECTS IN NATURAL SYSTEMS WILL BE EXAMINED IN PEAR, AN AGRICULTURAL CROP VALUED AT $429 MILLION IN 2018 IN THE UNITED STATES. VARIATION IN NECTAR CHEMISTRY AS WELL AS NECTAR/FLORAL VOLATILES WILL BE CHARACTERIZED THROUGH THE ASYMPTOMATIC PHASE OF BLOSSOM INFECTION. POLLINATOR BEHAVIORAL RESPONSES AND CONTRIBUTION TO PATHOGEN TRANSMISSION WILL BE ASSESSED THROUGH FIELD EXPERIMENTS. THIS PROPOSAL WILL PROVIDE AN INCREASED UNDERSTANDING OF PATHOGEN EFFECTS ON POLLINATION IN AGRICULTURAL SYSTEMS AND ENHANCE CURRENT POLLINATOR MANAGEMENT STRATEGIES IN ORCHARDS.