During 1989, a study was conducted to relate the resistance level of tobacco budworm, Heliothis virescens (F.), as measured by the adult vial test (AVT) to field control at a specific site throughout the season. Data were also collected using a neonate larval leaf dip bioassay. LC(50) values from the AVT ranged from a low of 1.78 µg/vial on June 29 to a high of 20.75 µg/vial on August 29. Male and female tobacco budworms did not differ significantly in their response (LC(50) and LC(90) levels) to cypermethrin. Also, the responses of tobacco budworm moths (29% males) hand-collected on August 30 did not differ significantly from the LC(50)'s and LC (90)'s of moths captured in pheromone traps on the same night. LC(50) values from the neonate larval bioassay ranged from 10.6 PPM in June to 34.8 PPM in August. Despite the increased tolerance to cypermethrin late in the season, adequate field control of Heliothis spp. was maintained throughout the test period. However, Heliothis spp. population pressure in the test plots was low, especially during late July and August.