Western corn rootworm is an important agricultural pest of corn. Transgenic corn producing toxins derived from the bacterium Bacillus thuringiensis Bt has been rapidly adopted by farmers. These Bt crops control many key agricultural pests such as corn rootworm. Thus, it is important to understand the durability of Bt crops. In order to delay pest resistance, farmers must plant a refuge (Box 1). Non-Bt corn is used with Bt corn as part of a refuge strategy (Figure 1). This study focuses on studying the durability of Bt corn as either a stacked event (SmartStax) or a single event (VTTriple Pro) in controlling the Western corn rootworm.