THE US GOVERNMENT VIEWED THE INSECTICIDAL PROPERTIES OF BACILLUS THURINGIENSIS (BT) AS A "PUBLIC GOOD" AND TOOK ACTION TO ENSURE THAT BT TRANSGENES MOVED INTO CROPS WERE USED IN A MANNER THAT DECREASED THE RISK OF PESTS EVOLVING RESISTANCE. FURTHERMORE, THE US-EPA AND USDA CONCLUDED THAT MONITORING FOR RESISTANCE COULD IMPROVE RESISTANCE MANAGEMENT PRACTICES. DESPITE THESE RECOMMENDATIONS, MEASURABLE FIELD-EVOLVED RESISTANCE TO BT CRY TOXINS HAS BEEN DESCRIBED FOR 8 MAJOR AGRICULTURAL PEST SPECIES, DEMONSTRATING THAT CURRENT MONITORING PRACTICES ARE INADEQUATE. WE RECENTLY APPLIED A NEW GENOMIC MONITORING APPROACH TO ARCHIVED, FIELD-COLLECTED POPULATIONS OF HELIOTHIS (CHLORIDEA) VIRESCENS AND HELICOVERPA ZEA. USING THIS APPROACH, WE IDENTIFIED DOZENS OF RAPIDLY CHANGING GENOMIC REGIONS IN H. VIRESCENS AND H. ZEA IN THE YEARS FOLLOWING BT CROP COMMERCIALIZATION. IN THE CASE OF H. VIRESCENS, OUR APPROACH DISCOVERED THE DECLINE OF A PYRETHROID RESISTANCE ALLELE AFTER BT-EXPRESSING COTTON REPLACED PYRETHROID SPRAYS AS THE PRIMARY H. VIRESCENS MANAGEMENT TACTIC BETWEEN 1997 AND 2012. WE ALSO DISCOVERED MAJOR CHANGES AT MARKERS THROUGHOUT THE GENOME OF H. ZEA BETWEEN 2012 AND 2016, YEARS DURING WHICH FIELD DAMAGE TO CRY1 AND CRY2 EXPRESSING BT CORN CULTIVARS INCREASED. AS WITH ANY RESISTANCE MONITORING APPROACH, GENOMIC MONITORING LIKELY HAS STRENGTHS AND WEAKNESSES. OUR PROPOSED RESEARCH AIMS TO SHED LIGHT ON THESE STRENGTHS AND WEAKNESSES USING A COMBINATION OF GENOMIC APPROACHES AND LABORATORY ASSAYS. WE WILL COMPARE THE RESULTS OF OUR PROPOSED RESEARCH WITH THOSE OF OUR PREVIOUS GENOMIC MONITORING EXPERIMENTS TO QUANTIFY THE TRUE POSITIVE, FALSE POSITIVE, AND FALSE NEGATIVE DISCOVERY TO RATES THAT CAN BE EXPECTED FOR GENOMIC MONITORING APPROACHES. OUR WORK WILL PROVIDE A QUANTITATIVE ASSESSMENT OF THE USE OF GENOMIC MONITORING APPROACHES FOR IDENTIFYING FIELD-EVOLVED RESISTANCE PRIOR TO YIELD LOSSES. WHILE THE PROPOSED RESEARCH PRIMARILY FOCUSES ON CRY RESISTANCE, OUR GOAL IS TO EXAMINE THE UTILITY OF THIS APPROACH FOR RESISTANCE MONITORING OF ANY PLANT-INCORPORATED INSECTICIDAL TRAIT.