To follow the seasonal and geographic development of pyrethroid resistance in Heliothis virescens, populations of H. virescens were monitored for pyrethroid resistance in Arkansas, Louisiana, and Mississippi during 1987. A total of 24,726 adult males were tested for susceptibility to cypermethrin via the treated vial technique. Results indicated that the frequency of pyrethroid resistant individuals declined in some areas of the Mid-South from May to June. In other areas, the frequency of resistant individuals increased through the growing season. Susceptibility varied with geographic location. Although insecticide usage is difficult to measure, entomologists think that most growers followed the resistance management strategy proposed for the Mid-South during 1986. Pyrethroid resistance appears to be manageable and further use of the resistance management strategy is encouraged.