THE WESTERN CORN ROOTWORM, DIABROTICA VIRGIFERA VIRGIFERA, IS THE MOST SERIOUS INSECT PEST OF CORN IN THE US CORN BELT, AND IS RESPONSIBLE FOR OVER $1 BILLION IN ANNUAL ECONOMIC LOSSES TO US FARMERS THROUGH THE COMBINE EFFECT OF YIELD LOSSES AND MANAGEMENT COSTS. ONE OF THE PRIMARY TOOLS USED TO MANAGE WESTERN CORN ROOTWORM IS CORN THAT HAS BEEN GENETICALLY ENGINEERED TO PRODUCE INSECTICIDAL TOXINS DERIVED FROM THE BACTERIUM BACILLUS THURINGIENSIS (BT) OR THROUGH GENE SILENCING VIA RNA INTERFERENCE (RNAI). FIELD-EVOLVED RESISTANCE BY WESTERN CORN ROOTWORM TO ALL AVAILABLE BT TRAITS HAS BEEN DOCUMENTED, AND BT-RESISTANCE BY WESTERN CORN ROOTWORM CAN BE ASSOCIATED WITH HIGH LEVELS OF FEEDING INJURY TO BT CORN IN THE FIELD. HOWEVER, DATA ARE CURRENTLY LACKING ON 1) THE PREVALENCE OF POPULATIONS WITH RESISTANCE TO MULTIPLE BT TRAITS, SPECIFICALLY BT CORN THAT PRODUCES BT TOXINS GPP34/TPP35AB1 AND CRY3BB1, AND 2) THE RISK POSED BY THE CONTINUED EVOLUTION OF RESISTANCE. THIS IS IMPORTANT BECAUSE STRATEGIES TO MANAGE RESISTANCE TO GENETICALLY ENGINEERED CORN BY WESTERN CORN ROOTWORM RELY ON THE PYRAMID/REFUGE STRATEGY. THE PYRAMID/REFUGE STRATEGY INVOLVES THE USE OF MULTIPLE INSECTICIDAL TOXINS (I.E., AN INSECTICIDAL PYRAMID) IN A SINGLE PLANT AND ACTS TO DELAY RESISTANCE BECAUSE INSECTS THAT ARE RESISTANT TO ONE TOXIN IN A PYRAMID ARE KILLED BY THE SECOND AND VICE VERSA. THE NEWEST TRAIT TO MANAGE WESTERN CORN ROOTWORM IS THE RNAI TRAIT, DVSNF7, AND THIS TRAIT WILL PROVIDE A SUBSTANTIAL BENEFIT TO FARMERS BECAUSE IT WILL ALLOW THEM TO MANAGE WESTERN CORN ROOTWORM THAT HAVE EVOLVED RESISTANCE TO AVAILABLE BT TRAITS. HOWEVER, THE RESISTANCE MANAGEMENT STRATEGY FOR DVSNF7 IS BASED ON THE PYRAMID/REFUGE STRATEGY WITH DVSNF7, PLACED IN A PYRAMID WITH GPP34/TPP35AB1 + CRY3BB1. CONSEQUENTLY, TO THE EXTENT THAT WESTERN CORN ROOTWORM POPULATIONS ARE RESISTANT TO GPP34/TPP35AB1 + CRY3BB1, THIS WILL DIMINISH THE BENEFIT OF USING A PYRAMID OF DVSNF7 + GPP34/TPP35AB1 + CRY3BB1, POTENTIALLY LEADING TO THE EVOLUTION OF WESTERN CORN ROOTWORM POPULATIONS THAT ARE RESISTANT TO ALL THREE OF THESE BIOTECHNOLOGY-BASED TRAITS. THROUGH A SERIES OF COMPLEMENTARY OBJECTIVES, I WILL QUANTIFY THE PREVALENCE OF RESISTANCE TO CORN CONTAINING A PYRAMID OF GPP34/TPP35AB1 AND CRY3BB1, AND THE RISK OF CONTINUED RESISTANCE EVOLUTION, BOTH TO GPP34/TPP35AB1 + CRY3BB1 CORN, AND THE NEWLY DEVELOPED DVSNF7 + GPP34/TPP35AB1 + CRY3BB1 CORN. THESE DATA WILL PROVIDE VALUABLE INFORMATION TO FEDERAL REGULATORS, BIOTECHNOLOGY COMPANIES, PUBLIC-SECTOR SCIENTISTS, FARMERS AND OTHER MEMBERS OF THE AGRICULTURAL COMMUNITY ON THE RISKS POSED BY THE EVOLUTION OF RESISTANCE TO GENETICALLY ENGINEERED CORN BY WESTERN CORN ROOTWORM, AND WILL HELP TO IMPROVE PLANS TO MANAGE RESISTANCE FOR THIS SERIOUS AGRICULTURAL PEST. THIS RESEARCH IS ALIGNED WITH BRAG PROGRAM AREA 5I: RESEARCH TO UNDERSTAND THE FREQUENCY AND MECHANISMS BY WHICH PESTS OR DISEASES OVERCOME PLANT PEST OR DISEASE RESISTANCE TRAITS CONFERRED B,Y ENGINEERED GENES.