Topical bioassays of cypermethrin, endosulfan, methomyl, profenofos, and sulprofos were conducted with the LSU laboratory colony (LSU-LAB) and field-collected colonies of tobacco budworm from Louisiana, Mississippi and Texas. The field-collected colonies exhibited low to high levels of resistance to cypermethrin (1-42x), low to moderate levels of resistance to profenofos and sulprofos (1-6x) and low to high levels of resistance to methomyl (2-12x) compared to the LSU-LAB colony. Conversely, LD(50) values for endosulfan were lower for the field-collected colonies than for the LSU-LAB colony. Spray chamber bioassays indicated reduced efficacy of cypermethrin, endosulfan, profenofos and thiodicarb against the field-collected colonies of tobacco budworms tested in comparison to insecticide efficacy against the Stoneville laboratory colony.