** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE PROJECT SEEKS TO MORE FULLY UNDERSTAND (THROUGH FIELD TESTING) THE OFF-SITE MOVEMENT OF PESTICIDES APPLIED IN ORCHARDS/VINEYARDS WHEN USING AIRBLAST SPRAYERS AND TO UTILIZE THE LEARNING IN DEVELOPING A COMPREHENSIVE MECHANISTIC MODEL TO PROVIDE ACCURATE AND RELIABLE SPRAY DRIFT ESTIMATES. THE SPECIFIC OBJECTIVES ARE TO: 1) DEVELOP A MECHANISTIC SPRAY DRIFT MODEL, BASED ON AN EXISTING DEPOSITION MODEL; 2) CONDUCT SPRAYER DISPLACEMENT FIELD TRIALS TO EXAMINE AND INTEGRATE INTO THE MODEL THE EFFECTS (ON DRIFT) OF MOVING SPRAYER TO DIFFERENT DRIVE LANES OF ORCHARD/VINEYARD; AND 3) VALIDATE THE DEVELOPED MODEL UTILIZING PREVIOUSLY GENERATED CANOPY, METEOROLOGICAL, AND DRIFT DATA FROM MULTIPLE CROPS (ALMOND, CITRUS, AND GRAPE). THE USE OF THE MODEL WILL ALSO INCREASE OUR KNOWLEDGE OF BEST PRACTICES FOR MINIMIZING DRIFT WHICH WILL TRANSLATE INTO RECOMMENDATIONS THAT WILL BE DISSEMINATED THROUGH EXTENSION PUBLICATIONS TO MAINTAIN OR IMPROVE THE USE OF SAFE, EFFECTIVE, SUSTAINABLE PEST MANAGEMENT PRACTICES IN CALIFORNIA AND OTHER TREE/VINE CROP PRODUCTION AREAS BOTH WITHIN AND BEYOND THE PROJECT PERIOD. THE MODEL WILL ALSO PROVIDE A BASIS FOR EVALUATING/INCORPORATING THE BENEFITS OF PRECISION APPLICATION INTO RISK ASSESSMENT AND RISK MITIGATION OF PESTICIDES. THIS FOCUS ON IMPROVING ENVIRONMENTAL SUSTAINABILITY WILL REDUCE PUBLIC HEALTH IMPACTS FROM HIGH-RISK PESTICIDES OF HIGH REGULATORY CONCERN.