The development of resistance to insecticides has been documented since 1914.  Insect resistance to inorganic insecticides, to organic insecticides, and to Bacillus thuringiensis (Bt) sprays has developed within 2 - 20 years of being applied against target insects.  Sound insect resistance management (IRM) programs require methods for monitoring insect populations for the onset of resistance.  Current methods of resistance monitoring include genetic, biochemical, and morphological assays.  However, whole-insect bioassays prevail as the most user-friendly and informative from the standpoint of practicality and timely pest-management decision-making.  Indeed, in the case of Plant-Incorporated Protectants (Bt cotton) and Lepdioptera, EPA requires registrants to conduct bioassays to monitor cotton bollworm, tobacco budworm, and pink bollworm for development of resistance to Cry1Ac, Cry1F, and Cry2Ab2 protein toxins.  Each of three currently-used insecticide resistance bioassays for Lepidoptera has limitations.  The adult vial test is limited to contact insecticides; and, the absence of a nectar source during the assay period may enhance moth susceptibility.  The larval feeding disruption test (FDT) field-kit requires significant time and effort to collect eggs or larvae from the field.  The F₂ screen likewise requires extensive resources to establish and test laboratory isolines based on field-collected gravid females.  Thus, we have worked to develop an economical alternative bioassay based on trap-collected adults and marker detection.