**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** EACH YEAR INSECTS AND PLANT PATHOGENS ARE RESPONSIBLE FOR THE LOSS OF HUNDREDS OF BILLIONS OF DOLLARS IN AGRICULTURAL PRODUCTIVITY WORLDWIDE. IN ADDITION TO IMMEDIATE DESTRUCTION OF PLANT TISSUES AND PRODUCTS, PATHOGENS INDUCE CHANGES IN PLANT GROWTH AND METABOLISM AND FREQUENTLY INFLUENCE BIOTIC INTERACTIONS IN WAYS THAT CAN INCREASE PATHOGEN TRANSMISSION. DAMAGE TO AGRICULTURAL PRODUCTIVITY AND INCREASED PATHOGEN TRANSMISSION CAN LEAD TO PROBLEMS WITH FOOD SAFETY AND FOOD SECURITY WITH DOMESTIC AND INTERNATIONAL IMPLICATIONS DESPITE THE DIVERSITY OF PATHOGEN LIFE HISTORIES, ONE EMERGING THEME IS THAT PATHOGENS THAT SHARE SIMILAR MODES OF TRANSMISSION ARE LIKELY TO INDUCE SIMILAR CHANGES IN THEIR HOSTS. THIS THEME HAS BEEN CENTRAL TO THE DEVELOPMENT OF A PREDICTIVE FRAMEWORK OUTLINING HOW INSECT-VECTORED PLANT PATHOGENS ARE LIKELY TO INFLUENCE HOST PLANT PHYSIOLOGY. HOWEVER, THIS PREDICTIVE FRAMEWORK IS ALMOST EXCLUSIVELY BASED ON EVIDENCE FROM INSECT-VECTORED PLANT VIRUSES AND HAS LIMITED TESTING IN NON-VIRAL SYSTEMS. THE MAJORITY OF PLANT PATHOGENS ARE FUNGAL. THIS PROJECT AIMS TO EVALUATE THE BENEFIT OF THIS PREDICTIVE FRAMEWORK IN A FUNGAL SYSTEM AND USES A SERIES OF LABORATORY BASED TRANSMISSION ASSAYS, INSECT BEHAVIORAL ASSAYS, MEASUREMENTS OF PLANT GENE EXPRESSION, AND CHEMICAL ANALYSIS OF PLANT METABOLISM TO ADDRESS THREE MAIN OBJECTIVES: 1) IDENTIFY FACTORS INFLUENCING THE TRANSMISSION OF INSECT-VECTORED FUNGAL PATHOGEN; 2) DETERMINE HOW FUNGAL INFECTION STATUS AFFECTS INSECT ATTRACTION TO HOST PLANTS; AND 3) EXAMINE HOW FUNGAL INFECTION ALTERS HOST PLANT QUALITY AND RESISTANCE TO HERBIVORE ATTACK. THESE OBJECTIVES WILL BE ADDRESSED USING A FOCAL PATHOGEN EREMOTHECIUM CORYLI, WHICH IS DISTRIBUTED GLOBALLY AND HAS A HOST-RANGE THAT INCLUDES NUMEROUS PLANT SPECIES OF AGRICULTURAL SIGNIFICANCE (E.G., SOYBEAN AND OTHER LEGUMES, COTTON, TOMATO, TREE NUTS, AND CITRUS). THESE EXPERIMENTS MAY ALSO HELP TO IDENTIFY TARGETS FOR FUTURE MANAGEMENT AND MONITORING OF INSECT VECTORS AND DETERMINE HOW E. CORYLI INFECTION INFLUENCES CROP PLANTS' SUSCEPTIBILITY TO OTHER STRESSORS.