Over 4100 male tobacco budworm moths were bioassayed from May through October 1989 against 10 and 30 µg/vial doses of cypermethrin. Examination of these data reveal that pyrethroid resistance in tobacco budworm varied with location and date of bioassay. Resistance levels decreased during May and June when pyrethroid use was low and increased dramatically during late July and August when pyrethroids were being used extensively. Overall pyrethroid resistance levels in May and June of 1989 were similar to that observed in 1987 and 1988. However, due to the fact that much of the 1989 cotton crop matured later than the 1987 and 1988 crops (which resulted in greater use of pyrethroids in August and September), pyrethroid resistance levels during August and September of 1989 were much higher than the levels recorded during those same months of 1987 and 1988. Resistance levels were generally highest in areas of extensive cotton production (hence more extensive use of pyrethroids) and lowest in areas with little or no commercial cotton production. overall, the data suggest that the Tri-State (Mid-South) Pyrethroid Resistance Management Plan has been successful in delaying pyrethroid resistance development in tobacco budworm. However low tobacco budworm populations during 1987 and 1988 were no doubt responsible for the virtual absence of field control failures during those years. Despite low tobacco budworm populations during 1989, there were numerous cotton fields in which control of tobacco budworms was less than normally expected and in a few fields, control was unacceptable. These field control failures were related to the higher levels of pyrethroid resistance observed during July, August and September. The higher levels of pyrethroid resistance observed in July, August and September of 1989 as compared to 1987 and 1988 suggest that more restrictions should be placed on use of pyrethroids if their efficacy against tobacco budworm is to be maintained.