Adult vial, adult topical, larval vial and larval topical bioassays were conducted on the PEG-US87 strain of tobacco budworm, Heliothis virescens (F.), to determine the relationships between these different tests in describing resistance. No difference was found between sexes in their response to cypeimethrin, although females tested with the adult vial bioassay exhibited a great deal of variability. Adult bioassays were more sensitive to increasing dosages of cypermethrin than were larval bioassays. Larval topical bioassays were dissimilar to both adult and larval vial bioassays. There was no difference between adult and larval vial bioassays. These studies suggest that testing male moths is a valid monitoring procedure, and that results from adult and larval vial bioassays can be directly compared.